Tritium isotopic exchange in air detritiation dryers

International Nuclear Information System (INIS)

Everatt, A.E.; Johnson, R.E.; Senohrabek, J.A.; Shultz, C.M.

1989-02-01

Isotopic exchange between tritiated and non-tritiated water species in a molecular sieve bed has been demonstrated. At high humidities (+6 degrees Celsius dew point) the rate of tritium isotopic exchange in a 2.4 L molecular sieve bed has been demonstrated to be at least 50% of published exchange rates. In an industrial-sized air detritiation dryer, utilizing the pretreatment technique of H 2 O steam washing to elute the residual tritium, a DF of 12 600 has been demonstrated when operating at an inlet vapor tritium concentration of 14 Ci/kg and at inlet and outlet dew points of 4.8 and -54 degrees Celsius, respectively. In the NPD dryer bed studied, which was not optimally designed for full benefit from isotopic exchange, at least one order of magnitude in additional detritiation is attributed to isotopic exchange in the unsaturated zone. The technique of eluting the residual tritium from an industrial sized bed by H 2 O washing at high temperature, high humidity and low bed loading has been demonstrated to be a fast and effective way of removing tritium from a molecular sieve bed during regeneration. The isotopic exchange model accurately predicted the exchange between tritiated and non-tritiated water species in a molecular sieve bed where there is no net adsorption or desorption. The model's prediction of the tritium breakthrough trend observed in the NPD tests was poor; however, a forced fit can be achieved if the exchange rates in the MTZ and the unsaturated zone are manipulated. More experiments are needed to determine the relative rates of tritium exchange in the saturated, mass transfer, and unsaturated zones of a dryer bed

Energy aAnalysis and Kinetics of Mint Leaves Dehydration Using Vibro-Fluidized Bed Heat Pump Dryer

Directory of Open Access Journals (Sweden)

S. M Ataei Ardestani

2015-03-01

Full Text Available Fluidized bed dryers have not yet been used for drying products such as mint leaves. This could be due to high porosity and low mechanical resistance resulting in poor quality of fluidization. Applying vibration has been recommended to overcome problems such as channeling and defluidization, and hence improving the fluidization quality. In this research, a laboratory scale vibro-fluidized bed heat pump dryer was designed and constructed for drying mint leaves. The experiments were conducted at vibration frequency of 80 Hz and amplitude of 3 mm. The velocity and temperature of the inlet air was controlled by an automatic control system. Experiments were carried out at 40, 50 and 60 °C, and two methods: heat pump drying (HPD and non-heat pump drying (NHPD. The results revealed that drying process primarily occurred in the falling rate period. Effective moisture diffusivity of the samples increased with increase in drying air temperature and varied from 4.26656×10-11 to 2.95872×10-10 m2 s-1 for the HPD method, and 3.71918×10-11 to 1.29196×10-10 m2 s-1 for the NHPD method and was within the reported range of 10-9 to 10-11 m2 s-1 for drying of food materials. The activation energy was determined to be 84 kJ mol-1 for the HPD and 54.34 kJ mol-1 for the NHPD, both have very good agreement with the results of other investigators. The coefficient of performance and specific moisture evaporation rate showed the acceptable performance of the heat pump system. Moreover, the energy consumption of the dryer for the NHPD method was more than the HPD method.

Breakage and drying behaviour of granules in a continuous fluid bed dryer: Influence of process parameters and wet granule transfer.

Science.gov (United States)

De Leersnyder, F; Vanhoorne, V; Bekaert, H; Vercruysse, J; Ghijs, M; Bostijn, N; Verstraeten, M; Cappuyns, P; Van Assche, I; Vander Heyden, Y; Ziemons, E; Remon, J P; Nopens, I; Vervaet, C; De Beer, T

2018-03-30

Although twin screw granulation has already been widely studied in recent years, only few studies addressed the subsequent continuous drying which is required after wet granulation and still suffers from a lack of detailed understanding. The latter is important for optimisation and control and, hence, a cost-effective practical implementation. Therefore, the aim of the current study is to increase understanding of the drying kinetics and the breakage and attrition phenomena during fluid bed drying after continuous twin screw granulation. Experiments were performed on a continuous manufacturing line consisting of a twin-screw granulator, a six-segmented fluid bed dryer, a mill, a lubricant blender and a tablet press. Granulation parameters were fixed in order to only examine the effect of drying parameters (filling time, drying time, air flow, drying air temperature) on the size distribution and moisture content of granules (both of the entire granulate and of size fractions). The wet granules were transferred either gravimetrically or pneumatically from the granulator exit to the fluid bed dryer. After a certain drying time, the moisture content reached an equilibrium. This drying time was found to depend on the applied airflow, drying air temperature and filling time. The moisture content of the granules decreased with an increasing drying time, airflow and drying temperature. Although smaller granules dried faster, the multimodal particle size distribution of the granules did not compromise uniform drying of the granules when the target moisture content was achieved. Extensive breakage of granules was observed during drying. Especially wet granules were prone to breakage and attrition during pneumatic transport, either in the wet transfer line or in the dry transfer line. Breakage and attrition of granules during transport and drying should be anticipated early on during process and formulation development by performing integrated experiments on the granulator

Test of a solar crop dryer

Energy Technology Data Exchange (ETDEWEB)

Oestergaard Jensen, S. [Teknologisk Institut. SolEnergiCentret, Taastrup (Denmark); Floejgaard Kristensen, E. [Danmarks JordbrugsForskning, Tjele (Denmark); Forman, T. [Aidt Miljoe A/S, Thorsoe (Denmark)

2001-01-01

One of the major goals of the project 'Test and Research Project into the Drying of Food and Wood Products with Solar Heat' was to develop and test a solar crop dryer for use in Ghana. Based on a survey in Ghana (Jensen, Frank and Kristensen, 1999) it was decided to develop a dryer for drying of maize for seed as the increase in value of the crop due the drying here would be high - the dryer may, however, also be used to dry other crops or other items - one unit will e.g. be erected in Ghana to test drying of fish. The capacity of the dryer was defined to be 500 kg having a collector area of approx 25 m{sup 2}. It was decided to let the dryer consist of 5 separate units each with a transparent collector area of 4.77 m{sup 2} and a capacity of approx. 100 kg. The modulized concept has several benfits: If one drying bed is operated improperly this will not affect the total quantity of crops being dried at that time. It is possible to dry different crops (creating different pressure drop) side by side without risking that the crop with the highest pressure drop will be dried improperly. Small dc fans are often cheaper than larger dc fans. The system will be less complex, and an even air distribution over the drying bed is easier obtainable. Finally it is possible to start with only one unit and then gradually increase the capacity of the solar dryer - this will make it easier to invest in a solar dryer. It was further decided that the fans of the dryer should be powered directly by PV-panels in order to make the dryer independent of an often unreliable, missing or expensive grid. The dryer is going to be erected and tested at Silwood Farms situated close to Accra. Silwood Farms has total land acreage of 210 acres where 176 acres are used for cultivating maize - the rest is used for gowing pineapple. A majority of the maize is processed into seed. The main harvest season for maize at Silwood Farms is August/September with a smaller harvest period in January

Performance Analysis of Solar Assisted Fluidized Bed Dryer Integrated Biomass Furnace with and without Heat Pump for Drying of Paddy

Directory of Open Access Journals (Sweden)

M. Yahya

2016-01-01

Full Text Available The performances of a solar assisted fluidized bed dryer integrated biomass furnace (SA-FBDIBF and a solar assisted heat pump fluidized bed dryer integrated biomass furnace (SAHP-FBDIBF for drying of paddy have been evaluated, and also drying kinetics of paddy were determined. The SA-FBDIBF and the SAHP-FBDIBF were used to dry paddy from 11 kg with moisture content of 32.85% db to moisture content of 16.29% db (14% wb under an air mass flow rate of 0.1037 kg/s within 29.73 minutes and 22.95 minutes, with average temperatures and relative humidities of 80.3°C and 80.9°C and 12.28% and 8.14%, respectively. The average drying rate, specific energy consumption, and specific moisture extraction rate were 0.043 kg/minute and 0.050 kg/minute, 5.454 kWh/kg and 4.763 kWh/kg, and 0.204 kg/kWh and 0.241 kg/kWh for SA-FBDIBF and SAHP-FBDIBF, respectively. In SA-FBDIBF and SAHP-FBDIBF, the dryer thermal efficiencies were average values of 12.28% and 15.44%; in addition, the pickup efficiencies were 33.55% and 43.84% on average, whereas the average solar and biomass fractions were 10.9% and 10.6% and 36.6% and 30.4% for SA-FBDIBF and SAHP-FBDIBF, respectively. The drying of paddy occurred in the falling rate period. The experimental dimensionless moisture content data were fitted to three mathematical models. Page’s model was found best to describe the drying behaviour of paddy.

Variation of the height of the grain bed of an indirect solar bin dryer; Variacion de la altura del lecho del grano en un secador solar indirecto

Energy Technology Data Exchange (ETDEWEB)

Sima, Efrain; Alvarez, Gabriela; Garcia, Saul [CENIDET, Cuernavaca, Morelos (Mexico)

2000-07-01

This paper presents the effect of the variation of the size of the grain bed of an indirect solar bin dryer. This solar dryer was designed and built at the Instituto Tecnologico de Zacatepec and Sima performed the thermal evaluation. The solar bin dryer consists of a bin dryer of 0.92 m diameter and 1 m height (the maximum height of the grain bed is 0.6 m). a 2 m{sup 2} solar collector, a blower and an electronic card to control the inlet air flow of the bin. A load of 36 kg, 45 kg, 52 kg and 64 kg of corn were dried. The heights of the grain were 7.5 cm, 10 cm, 12.5 cm and 17 cm respectively. Solar radiation, inlet air velocity of the solar collector, pressure drop, grain temperature and humidity, ambient temperature and humidity of the drying air were recorded. The initial grain humidity was 27.2% and the final was 11.8%. [Spanish] En este trabajo se presenta el efecto de la variacion del lecho del grano en el proceso de secado de maiz, en un prototipo de secador solar de tipo indirecto. El secador fue disenado y construido en el Tecnologico de Zacatepec y evaluado por Sima, consta de una camara de secado de 0.92 m de diametro y una altura de 1 m. (la altura del lecho maximo de grano posible es de 0.6 m.), un colector solar con un area de 2 m{sup 2}, un extractor de aire y un control electronico para el flujo de aire. El secado de maiz se llevo a cabo con cargas de maiz de 36, 45, 52 y 64 kg. Las alturas en el lecho del grano fueron 7.5, 10, 12.5 y 17 cm. Para cada altura de lecho de grano se realizo una prueba. Durante cada prueba se realizaron mediciones de: radiacion solar, velocidad del aire a la entrada, caida de presion, temperatura del grano, humedad del grano, temperatura del aire ambiente, temperatura y humedad del aire de secado a la entrada y salida del secador. La humedad inicial del grano fue alrededor de 27.2% y la final de 11.8%.

Mathematical Modelling of Drying Kinetics of Wheat in Electron Fired Fluidized Bed Drying System

Science.gov (United States)

Deomore, Dayanand N.; Yarasu, Ravindra B.

2018-02-01

The conventional method of electrical heating is replaced by electron firing system. The drying kinetics of wheat is studied using electron fired fluidized bed dryer. The results are simulated by using ANSYS. It was observed that the graphs are in agreement with each other. Therefore, the new proposed electronic firing system can be employed instead of electrical firing. It was observed that the drop in Relative Humidity in case of Electrical heating is 68.75% for temp reaching up to 70° C in 67 sec for pressure drop of 13 psi while for the electronic Firing system it is 67.6 % temp reaches to 70° C in 70 sec for pressure drop of 12.67 psi. As the results are in agreement with each other it was concluded that for the grains like wheat which has low initial moisture content both systems can be used.

Modelling Condensation and Simulation for Wheat Germ Drying in Fluidized Bed Dryer

Directory of Open Access Journals (Sweden)

Der-Sheng Chan

2018-06-01

Full Text Available A low-temperature drying with fluidized bed dryer (FBD for wheat germ (WG stabilization could prevent the loss of nutrients during processing. However, both evaporation and condensation behaviors occurred in sequence during FBD drying of WG. The objective of this study was to develop a theoretical thin-layer model coupling with the macro-heat transfer model and the bubble model for simulating both the dehydration and condensation behaviors of WG during low-temperature drying in the FBD. The experimental data were also collected for the model modification. Changes in the moisture content of WG, the air temperature of FBD chamber, and the temperature of WG during drying with different heating approaches were significantly different. The thermal input of WG drying with short heating time approach was one-third of that of WG drying with a traditional heating approach. The mathematical model developed in this study could predict the changes of the moisture content of WG and provide a good understanding of the condensation phenomena of WG during FBD drying.

Effect of distributor on performance of a continuous fluidized bed dryer

Science.gov (United States)

Yogendrasasidhar, D.; Srinivas, G.; Pydi Setty, Y.

2018-03-01

Proper gas distribution is very important in fluidized bed drying in industrial practice. Improper distribution of gas may lead to non-idealities like channeling, short circuiting and accumulation which gives rise to non-uniform quality of dried product. Gas distribution depends on the distributor plate used. Gas distribution mainly depends on orifice diameter, number of orifices and opening area of the distributor plate. Small orifice diameter leads to clogging, and a large orifice diameter gives uneven distribution of gas. The present work involves experimental studies using different distributor plates and simulation studies using ASPEN PLUS steady state simulator. The effect of various parameters such as orifice diameter, number of orifices and the opening area of the distributor plate on the performance of fluidized bed dryer have been studied through simulation and experimentation. Simulations were carried out (i) with increasing air inlet temperature to study the characteristics of solid temperature and moisture in outlet (ii) with increasing orifice diameter and (iii) with increase in number orifices to study the solid outlet temperature profiles. It can be observed from the simulation that, an increase in orifice diameter and number orifices increases solid outlet temperature upto certain condition and then after there is no effect with further increase. Experiments were carried out with increasing opening area (3.4 to 42%) in the form of increasing orifice diameter keeping the number of orifices constant and increasing number of orifices of the distributor plate keeping the orifice diameter constant. It can be seen that the drying rate and solid outlet temperature increase upto certain condition and then after with further increase in the orifice diameter and number of orifices, the change in the drying rate and solid outlet temperature observed is little. The optimum values of orifice diameter and number of orifices from experimentation are found to be 5

Evaluation of drying models of apple (var. Ligol) dried in a fluidized bed dryer

International Nuclear Information System (INIS)

Kaleta, Agnieszka; Górnicki, Krzysztof; Winiczenko, Radosław; Chojnacka, Aneta

2013-01-01

Highlights: ► Three new drying models are formulated. ► The developed models are various modifications of the Page model. ► Nineteen models are used to describe the fluidized bed drying of apple. ► The Page model and formulated model is considered as the most appropriate. - Abstract: Three new drying models were formulated. The developed models are various modifications of the Page model. The models were used to describe the drying behaviour of apple (var. Ligol) dried in a fluidized bed dryer. The suitability of new models to describe the drying characteristics were compared to the accuracy of sixteen models available from the literature. The accuracies of the models were measured using the correlation coefficient (R), root mean square error (RMSE), and reduced chi-square (χ 2 ). Three new developed models described the drying characteristics of apple cubes satisfactorily (R > 0.997). The Page model and one of the empirical models formulated by the authors of this study can be considered as the most appropriate (R > 0.9977, RMSE = 0.0094–0.0167, χ 2 = 0.0001–0.0002). The effect of drying air temperature on the drying models parameters were also determined. The shrinkage of apple cubes during drying was measured to assess the changes in quality of dried apples

performance evaluation of a pebble bed solar crop dryer abstract

African Journals Online (AJOL)

Dr Obe

The open-air sun drying is prevalent and very common in the rural areas. Farmers spread their agricultural produce such as maize, cassava, pepper, tomatoes etc. ... drying system. The abundance of solar radiation in. Nigeria could make crop drying with solar dryers very easy and simple. Economic appraisal of solar drying ...

Experimental study of regenerative desiccant integrated solar dryer with and without reflective mirror

Energy Technology Data Exchange (ETDEWEB)

Shanmugam, V. [Department of Mechanical Engineering, Sathyabama University, Chennai, 600 119 (India); Natarajan, E. [Institute for Energy Studies, College of Engineering, Anna University, Chennai, 600 025 (India)

2007-06-15

An indirect forced convection with desiccant integrated solar dryer has been built and tested. The main parts are: a flat plate solar air collector, a drying chamber, desiccant bed and a centrifugal blower. The system is operated in two modes, sunshine hours and off sunshine hours. During sun shine hours the hot air from the flat plate collector is forced to the drying chamber for drying the product and simultaneously the desiccant bed receives solar radiation directly and through the reflected mirror. In the off sunshine hours, the dryer is operated by circulating the air inside the drying chamber through the desiccant bed by a reversible fan. The dryer is used to dry 20 kg of green peas and pineapple slices. Drying experiments were conducted with and without the integration of desiccant unit. The effect of reflective mirror on the drying potential of desiccant unit was also investigated. With the inclusion of reflective mirror, the drying potential of the desiccant material is increased by 20% and the drying time is reduced. The drying efficiency of the system varies between 43% and 55% and the pick-up efficiency varies between 20% and 60%, respectively. Approximately in all the drying experiments 60% of moisture is removed by air heated using solar energy and the remainder by the desiccant. The inclusion of reflective mirror on the desiccant bed makes faster regeneration of the desiccant material. (author)

Thermal decomposition of uranylnitrate by the Spray-Dryer process

International Nuclear Information System (INIS)

Wildhagen, G.R.S.; Silva, G.C. da

1988-01-01

The proposal of this work consist in the thermal decomposition of uranyl nitrate solutions by the Spray-Dryer process aiming the production of highly reactive fluidized UO 3 , adequate for the use in posterior of reduction to UO 2 and hydrofluorination to UF 4 , in a fluidized bed for the obtention of UF 6 in the cicle of nuclear fuels. (author) [pt

Enhancement of Energy Efficiency and Food Product Quality Using Adsorption Dryer with Zeolite

Directory of Open Access Journals (Sweden)

Moh Djaeni

2013-06-01

Full Text Available Drying is a basic operation in wood, food, pharmaceutical and chemical industry. Currently, several drying methods are often not efficient in terms of energy consumption (energy efficiency of 20-60% and have an impact on product quality degradation due to the introduction of operational temperature upper 80oC. This work discusses the development of adsorption drying with zeolite to improve the energy efficiency as well as product quality. In this process, air as drying medium is dehumidified by zeolite. As a result humidity of air can be reduced up to 0.1 ppm. So, for heat sensitive products, the drying process can be performed in low or medium temperature with high driving force. The study has been conducted in three steps: designing the dryer, performing laboratory scale equipment (tray, spray, and fluidised bed dryers with zeolite, and evaluating the dryer performance based on energy efficiency and product quality. Results showed that the energy efficiency of drying process is 15-20% higher than that of conventional dryer. In additon, the dryer can speed up drying time as well as retaining product quality.

Fluid bed dryer and Aeropep solidification system

International Nuclear Information System (INIS)

1975-01-01

Performance measurements were made on the model of the Fluidized-bed Calciner developed by Aerojet Liquid Rocket Co. The measurements were made over the period August 11-19, 1975, at the Sacramento location of the calciner. The purpose of the tests was to evaluate the performance of the ALRC Fluidized Bed Concentrator for the processing of simulated waste containing realistic concentrations and chemical forms of radioiodine. (auth)

Removal of SO2 and NO/sub x/ from flue gas by means of a spray dryer/electron beam combination: a feasibility study

International Nuclear Information System (INIS)

Helfritch, D.J.; Feldman, P.L.; Ray, A.B.; Morgan, J.R.; Hildreth, G.A.

1982-04-01

This study examines the feasibility of adding an electron beam between the spray dryer and the fabric filter of dry scrubber flue gas desulfurization (FGD) systems. The beam promises effective removal of nitrogen oxides (NO/sub x/) and sulfur dioxide (SO 2 ), even at higher coal-sulfur levels than usually economic for dry scrubbers. The beam excites gas molecules, promoting reactions that convert SO 2 and NO/sub x/ to acids that then react with calcium compounds and are removed by the filter. Concerns examined here are feasibility and waste disposal. The cost findings are promising for both manufacture and operation. The system uses commercially available components. The relatively low temperatures and high humidity downstream of the spray dryer favor economic beam operation. The beam removes SO 2 , so the dryer can be run for economy, not high removal. The beam's incidental heating effect reduces reheat cost. Safe landfilling of the nitrate-rich waste appears practical, with leachate carrying no more nitrate than natural rain and dustfall. We expect natural pozzolanic reactions between alumina-silica compounds in the fly ash and lime compounds from the spray dryer to form an impermeable concrete-like material within 10 days after landfilling. Dry scrubber with electron beam appears competitive with commercial FGD systems, and we recommend a pilot scale operation

Test of solar dryers in Ghana

Energy Technology Data Exchange (ETDEWEB)

Oestergaard Jensen, S. [Teknologisk Institut. SolEnergiCentret, Taastrup (Denmark); Floejgaard Kristensen, E. [Danmarks JordbrugsForskning, Tjele (Denmark); Agyei, F. [FAGOD Ltd. (Ghana); Larsen, T. [Clipper Design Ltd. (Ghana); Nketiah, K.S. [FORIG (Ghana)

2002-06-01

The report describes the tests carried out in Ghana on three solar dryers as part of the project 'Test and Research Project into the Drying of Food and Wood Products with Solar Heat' financed by DANIDA. The main objective of the project was to develop and test solar dryers for crop, fish and wood in Ghana. Three dryers were erected: 1. Solar crop dryer: The solar crop dryer was erected at Silwood Farms at Pokuase about 30 km north of Accra. Silwood Farms grows primarily maize for seed and pineapples, 2. Solar fish dryer: The solar fish dryer was erected at Elite Enterprise Ltd. at Tema about 35 km east-north-east of Accra. Elite Enterprise Ltd. buys and dries fish, 3. Solar wood dryer: The solar wood dryers were erected at Clipper Design Ltd. at Mankoadze about 65 km west-south-west of Accra. Clipper Design Ltd. produces mainly doors. (BA)

Performance of indirect solar cabinet dryer

International Nuclear Information System (INIS)

Sreekumar, A.; Manikantan, P.E.; Vijayakumar, K.P.

2008-01-01

In this paper, the development and testing of a new type of efficient solar dryer, particularly meant for drying vegetables and fruit, is described. The dryer has two compartments: one for collecting solar radiation and producing thermal energy and the other for spreading the product to be dried. This arrangement was made to absorb maximum solar radiation by the absorber plate. In this dryer, the product was loaded beneath the absorber plate, which prevented the problem of discoloration due to irradiation by direct sunlight. Two axial flow fans, provided in the air inlet, can accelerate the drying rate. The dryer had six perforated trays for loading the material. The absorber plate of the dryer attained a temperature of 97.2 deg. C when it was studied under no load conditions. The maximum air temperature in the dryer, under this condition was 78.1 deg. C. The dryer was loaded with 4 kg of bitter gourd having an initial moisture content of 95%, and the final desired moisture content of 5% was achieved within 6 h without losing the product colour, while it was 11 h for open sun drying. The collector glazing was inclined at a particular angle, suitable to the location, for absorption of maximum solar radiation. A detailed performance analysis was done by three methods, namely 'annualized cost method', 'present worth of annual savings' and 'present worth of cumulative savings'. The drying cost for 1 kg of bitter gourd was calculated as Rs. 17.52, and it was Rs. 41.35, in the case of an electric dryer. The life span of the solar dryer was assumed to be 20 years. The cumulative present worth of annual savings over the life of the solar dryer was calculated for bitter gourd drying, and it turned out be Rs. 31659.26, which was much higher than the capital cost of the dryer (Rs. 6500). The payback period was calculated as 3.26 years, which was also very small considering the life of the system (20 years). So, the dryer would dry products free of cost during almost its

Performance of indirect solar cabinet dryer

Energy Technology Data Exchange (ETDEWEB)

Sreekumar, A.; Manikantan, P.E.; Vijayakumar, K.P. [Solar Thermal Energy Laboratory, Department of Physics, Cochin University of Science and Technology, Kochi 682 022 (India)

2008-06-15

In this paper, the development and testing of a new type of efficient solar dryer, particularly meant for drying vegetables and fruit, is described. The dryer has two compartments: one for collecting solar radiation and producing thermal energy and the other for spreading the product to be dried. This arrangement was made to absorb maximum solar radiation by the absorber plate. In this dryer, the product was loaded beneath the absorber plate, which prevented the problem of discoloration due to irradiation by direct sunlight. Two axial flow fans, provided in the air inlet, can accelerate the drying rate. The dryer had six perforated trays for loading the material. The absorber plate of the dryer attained a temperature of 97.2 C when it was studied under no load conditions. The maximum air temperature in the dryer, under this condition was 78.1 C. The dryer was loaded with 4 kg of bitter gourd having an initial moisture content of 95%, and the final desired moisture content of 5% was achieved within 6 h without losing the product colour, while it was 11 h for open sun drying. The collector glazing was inclined at a particular angle, suitable to the location, for absorption of maximum solar radiation. A detailed performance analysis was done by three methods, namely 'annualized cost method', 'present worth of annual savings' and 'present worth of cumulative savings'. The drying cost for 1 kg of bitter gourd was calculated as Rs. 17.52, and it was Rs. 41.35, in the case of an electric dryer. The life span of the solar dryer was assumed to be 20 years. The cumulative present worth of annual savings over the life of the solar dryer was calculated for bitter gourd drying, and it turned out be Rs. 31659.26, which was much higher than the capital cost of the dryer (Rs. 6500). The payback period was calculated as 3.26 years, which was also very small considering the life of the system (20 years). So, the dryer would dry products free of cost

Drying of materials in fluidized bed: mathematical modeling

International Nuclear Information System (INIS)

Wildhagen, Gloria Regina S.; Silva, Eder F.; Calcada, Luis A.; Massarani, Giulio

2000-01-01

A three phase mathematical model for drying process in a fluidized bed was established. This model representing a bubble, interstitial gas and solid phase was based on principles of mass and energy conservation and on empirical relations for heat and mass transfer between phases. A fluidized bed dryer was built to test the results of proposed model with those obtained by experiments using alumina particles as a bed charge. A good agreement between the numerical and the experimental results were observed(author)

Integrated drying and incineration of wet sewage sludge in combined bubbling and circulating fluidized bed units.

Science.gov (United States)

Li, Shiyuan; Li, Yunyu; Lu, Qinggang; Zhu, Jianguo; Yao, Yao; Bao, Shaolin

2014-12-01

An original integrated drying and incineration technique is proposed to dispose of sewage sludge with moisture content of about 80% in a circulating fluidized bed. This system combines a bubbling fluidized bed dryer with a circulating fluidized bed incinerator. After drying, sewage sludge with moisture less than 20% is transported directly and continuously from the fluidized bed dryer into a circulating fluidized bed incinerator. Pilot plant results showed that integrated drying and incineration is feasible in a unique single system. A 100 t/d Sewage Sludge Incineration Demonstration Project was constructed at the Qige sewage treatment plant in Hangzhou City in China. The operational performance showed that the main operation results conformed to the design values, from which it can be concluded that the scale-up of this technique is deemed both feasible and successful. Copyright © 2014 Elsevier Ltd. All rights reserved.

Powder bed charging during electron-beam additive manufacturing

International Nuclear Information System (INIS)

Cordero, Zachary C.; Meyer, Harry M.; Nandwana, Peeyush; Dehoff, Ryan R.

2017-01-01

Electrons injected into the build envelope during powder bed electron-beam additive manufacturing can accumulate on the irradiated particles and cause them to repel each other. Under certain conditions, these electrostatic forces can grow so large that they drive the particles out of the build envelope in a process known as “smoking”. In the present work, we investigate the causes of powder bed charging and smoking during electron-beam additive manufacturing. In the first part of the paper, we characterize the surface chemistry of a common feedstock material—gas-atomized Ti-6Al-4V powder—and find that a thick, electrically insulating oxide overlayer encapsulates the particles. Based on these experimental results, we then formulate an analytical model of powder bed charging in which each particle is approximated as a capacitor, where the particle and its substrate are the electrodes and the oxide overlayer is the dielectric. Using this model, we estimate the charge distribution in the powder bed, the electrostatic forces acting on the particles, and the conditions under which the powder bed will smoke. It is found that the electrical resistivity of the oxide overlayer strongly influences the charging behavior of the powder bed and that a high resistivity promotes charge accumulation and consequent smoking. This analysis suggests new quality control and process design measures that can help suppress smoking.

Steam generator with perfected dryers

International Nuclear Information System (INIS)

Fenet, J.C.

1987-01-01

This steam generator has vertically superposed array of steam dryers. These dryers return the steam flow of 180 0 . The return of the water is made by draining channels to the steam production zone [fr

Multi-shelf domestic solar dryer

International Nuclear Information System (INIS)

Singh, Parm Pal; Singh, Sukhmeet; Dhaliwal, S.S.

2006-01-01

The solar dryer described in this paper can be used for drying various products at home under hygienic conditions with the self guarantee of adulteration free product. This solar dryer is of multi-shelf design, consisting of three perforated trays arranged one above the other. The drying air flows through the product by natural circulation. One of its novel features is variable inclination to capture more solar energy in different seasons. Another novel feature is the option to dry product under shade or without shade as per requirement. The rate of drying is uniform in all the trays due to heating of the air by solar energy in between the trays. The maximum stagnation temperature of this solar dryer was found to be 100 deg. C in the month of November at Ludhiana (31 o N). The moisture evaporation on the 1st, 2nd and 3rd drying day for drying fenugreek leaves was 0.23, 0.18 and 0.038 kg/m 2 h. To overcome the problem of reduction in efficiency on the second and third drying day, a semi-continuous mode of loading has been investigated, in which the efficiency remains almost the same on all drying days. The drying rate in the dryer was more than double that in open shade drying. Moreover, the final moisture content of the product was low enough (7.3% wb) for grinding it to a powder form and for good shelf life (1 year). An uncertainty analysis was performed, and the uncertainty in the efficiency was found to be 1.35%. An economic analysis was performed by three methods. The cost of drying fenugreek leaves in the domestic solar dryer turned out to be about 60% of that in an electric dryer. The cumulative present worth of the savings are much higher (18,316 Rupees) than the capital cost of the dryer (1600 Rupees). The payback period is also very low (<2 years) as compared to the life of the dryer (20 years), so the dryer will dry product free of cost during almost its entire life period. The quality and shelf life of the dried products are comparable to those of

Drying of carrot slices in a triple pass solar dryer

Directory of Open Access Journals (Sweden)

Seshachalam Kesavan

2017-01-01

Full Text Available An indirect triple pass forced convection solar dryer was developed and its performance was evaluated for drying of carrot slices. The drying experiments were carried out under the meteorological conditions of Coimbatore city in India during the year 2016. The experimental set-up consists of a blower, triple pass packed bed air collector (using sand with wire mesh absorber plate, and a drying chamber. The air mass flow rate was optimized to 0.062 kg/s. The initial moisture content of the carrot slices was reduced from 87.5% (on wet basis to the final moisture content of 10% (wet basis in 6 h duration. The thin layer drying characteristics were analyzed using twelve mathematical models available in open literature. The results showed that the pick-up efficiency of the dryer was varied in the range between 14 and 43% with an average air collector thermal efficiency of 44% during the experimentation. The drying characteristics of carrot slices was predicted with good degree of accuracy using Wang and Singh drying model.

Simulation of Hybrid Solar Dryer

International Nuclear Information System (INIS)

Yunus, Y M; Al-Kayiem, H H

2013-01-01

The efficient performance of a solar dryer is mainly depending on the good distribution of the thermal and flow field inside the dryer body. This paper presents simulation results of a solar dryer with a biomass burner as backup heater. The flow and thermal fields were simulated by CFD tools under different operational modes. GAMBIT software was used for the model and grid generation while FLUENT software was used to simulate the velocity and temperature distribution inside the dryer body. The CFD simulation procedure was validated by comparing the simulation results with experimental measurement. The simulation results show acceptable agreement with the experimental measurements. The simulations have shown high temperature spot with very low velocity underneath the solar absorber and this is an indication for the poor design. Many other observations have been visualized from the temperature and flow distribution which cannot be captured by experimental measurements.

Recent advances in fluidized bed drying

Science.gov (United States)

Haron, N. S.; Zakaria, J. H.; Mohideen Batcha, M. F.

2017-09-01

Fluidized bed drying are very well known to yield high heat and mass transfer and hence adopted to many industrial drying processes particularly agricultural products. In this paper, recent advances in fluidized bed drying were reviewed and focus is given to the drying related to the usage of Computational Fluid Dynamics (CFD). It can be seen that usage of modern computational tools such as CFD helps to optimize the fluidized bed dryer design and operation for lower energy consumption and thus better thermal efficiency. Among agricultural products that were reviewed in this paper were oil palm frond, wheat grains, olive pomace, coconut, pepper corn and millet.

40 CFR 1065.342 - Sample dryer verification.

Science.gov (United States)

2010-07-01

...-membrane dryer or thermal chiller. (d) Sample dryer verification procedure. Use the following method to... highest sample water content that you estimate during emission sampling. (3) Introduce the humidified gas... sampling system at a temperature at least 5 °C above the local humidified gas dewpoint. For dryers used in...

Evaluation and mitigation of tritium memory in detritiation dryers

International Nuclear Information System (INIS)

Malara, C.; Ricapito, I.; Edwards, R.A.H.; Toci, F.

1999-01-01

In atmospheric detritiation, and other tritium processes, tritium is adsorbed on zeolites (molecular sieves) in the form of tritiated water. Regeneration removes almost all the physically adsorbed water, but a proportion remains permanently in the zeolite and binder structure as chemically bound water or hydroxyl groups. Exchange between adsorbed water and bound water means that tritiated water is retained in the structure after regeneration. At the end of its life, the zeolite therefore constitutes a tritiated waste. Furthermore, if an atmosphere detritiation dryer (ADD) gets highly contaminated from a tritium spill, retained tritium contaminates both the small amount of vapour leaving the bed during the next drying cycle, and the water produced in the subsequent regeneration. This report first describes experiments to measure the tritiated water retained in a 5A zeolite bed after standard regeneration treatments, and then investigates strategies to mitigate the effect: more thorough regeneration and isotope swamping or elution. The effect of zeolite ageing after thermal cycling is also seen. (orig.)

Testing Report: Littleford-Day Dryer Operation: Dryer Operation Impacts of Proposed MIS Mitigation Changes

Energy Technology Data Exchange (ETDEWEB)

Shimskey, Rick W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Buchmiller, William C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Elmore, Monte R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2007-06-01

Pacific Northwest National Laboratory performed a series of tests using the Littleford Day 22-liter dryer during investigations that evaluated changes in the melter-feed composition for the Demonstration Bulk Vitrification System. During testing, a new melter-feed formulation was developed that improved dryer performance while improving the retention of waste salts in the melter feed during vitrification.

Herbal dryer: drying of ginger (zingiber officinale) using tray dryer

Science.gov (United States)

Haryanto, B.; Hasibuan, R.; Alexander; Ashari, M.; Ridha, M.

2018-02-01

Drying is widely used as a method to preserve food because of its convenience and affordability. Drying of ginger using tray dryer were carried out at various drying conditions, such as air-drying flow, air-drying temperature, and sample dimensions, to achieve the highest drying rate. Samples with various dimensions were placed in the tray dryer and dried using various air-drying flow and temperatures. The weights of samples were observed every 3 minutes interval. Drying was stopped after three times of constant weighing. Data of drying was collected to make the drying curves. Drying curves show that the highest drying rate is achieved using highest air flow and temperature.

Thermal Testing Methods for Solar Dryers

DEFF Research Database (Denmark)

Singh, Shobhana

2017-01-01

Solar food drying is a complex heat and mass transfer phenomena which depend on a number of drying process-dependent parameters such as operating conditions and characteristics of the food product to be dried. The variation in these parameters significantly affects the overall performance...... of the dryer system. Since commercial growth and acceptance of any solar dryer system momentously depend on its performance guarantee, the development of a standard methodology for their thermal testing has become necessary. The standard testing method not only provides better performance management...... of the dryer system but allows the manufacturers to achieve competitive efficiency and good product quality by comparing the available designs. In this chapter, an extensive review of solar dryer performance evaluation has been carried out. Furthermore, the chapter describes the existing testing procedures...

BWR Steam Dryer Alternating Stress Assessment Procedures

Energy Technology Data Exchange (ETDEWEB)

Morante, R. J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hambric, S. A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ziada, S. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2016-12-01

This report presents an overview of Boiling Water Reactor (BWR) steam dryer design; the fatigue cracking failures that occurred at the Quad Cities (QC) plants and their root causes; a history of BWR Extended Power Uprates (EPUs) in the USA; and a discussion of steam dryer modifications/replacements, alternating stress mechanisms on steam dryers, and structural integrity evaluations (static and alternating stress).

An experimentally validated simulation model for a four-stage spray dryer

DEFF Research Database (Denmark)

Petersen, Lars Norbert; Poulsen, Niels Kjølstad; Niemann, Hans Henrik

2017-01-01

mathematical model is an index-1 differential algebraic equation (DAE) model with 12 states, 9 inputs, 8 disturbances, and 30 parameters. The parameters in the model are identified from well-excited experimental data obtained from the industrialtype spray dryer. The simulated outputs ofthe model are validated...... is divided into four consecutive stages: a primary spray drying stage, two heated fluid bed stages, and a cooling fluid bed stage. Each of these stages in the model is assumed ideally mixed and the dynamics are described by mass- and energy balances. These balance equations are coupled with constitutive...... equations such as a thermodynamic model, the water evaporation rate, the heat transfer rates, and an equation for the stickiness of the powder (glass transition temperature). Laboratory data is used to model the equilibrium moisture content and the glass transition temperature of the powder. The resulting...

Investigation of the drying airflow at a newly developed dryer geometry for mixed flow grain dryers

Directory of Open Access Journals (Sweden)

Holger Scaar

2016-06-01

Full Text Available The mixed-flow dryer has been a matter of investigation many times regarding drying efficiency, dryer control, and performance enhancement over the past years. However, there is still considerable demand for optimization in terms of energy efficiency and homogeneity of drying. In order to analyze the specific energy consumption and the homogeneity of the drying process, different thermodynamic process conditions have been investigated for the conventional MFD design using numerical and experimental methods. Based on the results obtained, a novel dryer design has been developed. With this, a considerable increase of efficiency is expected. As the fluid dynamic analysis of the first design draft revealed, further development is required until scaling-up and transfer into practice will be possible. While homogeneous airflow conditions could be demonstrated in the core flow region in the center of the dryer, the configuration must be optimized in the near wall regions.

GAS DRYER DESIGN FOR VERMICELLI USING MICROCONTROLLER ATMEGA 8535

Directory of Open Access Journals (Sweden)

Akhmad Mufasil

2013-04-01

Full Text Available The purpose of this research is designing a gas dryer for vermicelli using a microcontroller ATmega 8535 that can overcome the obstacles in the drying department. The microcontroller ATmega 8535 used to regulate the temperature of the drying chamber. This tool design is made to compare between conventional dryer and a theoritical gas dryer in the factory. The method used in this paper is field study in the factory. Based on the experience then theoritical gas dryer design from the factory’s datas. A microcontroller Atmega 8535 is added to the dryer to easier the dryer operation. The result of the theoritical gas dryer design for vermicelli using a microcontroller ATmega 8535, showed a faster time drying for 131,04 kg of vermicelli need 47,72 minutes at a temperature of 40- 55° C.

Heat pump dryers theory, design and industrial applications

CERN Document Server

Alves-Filho, Odilio

2015-01-01

Explore the Social, Technological, and Economic Impact of Heat Pump Drying Heat pump drying is a green technology that aligns with current energy, quality, and environmental concerns, and when compared to conventional drying, delivers similar quality at a lower cost. Heat Pump Dryers: Theory, Design and Industrial Applications details the progression of heat pump drying-from pioneering research and demonstration work to an applied technology-and establishes principles and theories that can aid in the successful design and application of heat pump dryers. Based on the author's personal experience, this book compares heat pump dryers and conventional dryers in terms of performance, quality, removal rate, energy utilization, and the environmental effect of both drying processes. It includes detailed descriptions and layouts of heat pump dryers, outlines the principles of operation, and explains the equations, diagrams, and procedures used to form the basis for heat pump dryer dimensioning and design. The author ...

Hydrodynamics study on drying of pepper in swirling fluidized bed dryer (SFBD)

Science.gov (United States)

Syaif Haron, Nazrul; Hazri Zakaria, Jamal; Faizal Mohideen Batcha, Mohd

2017-08-01

Malaysia is one of the pepper producer with exports quantity reaching more than 90000 tonnes between 2010 until 2016. Drying of pepper is mandatory before their export and at present, pepper was dried by sun drying to reduce cost. This conventional drying method was time consuming and may take four days during rainy season, which retards the production of pepper. This paper proposes the swirling fluidized bed drying (SFBD) method, which was known to have high mixing ability and improved solid-gas contact to shorten the drying time of products. A lab scale SFBD system was constructed to carry out this study. Hydrodynamic study was conducted for three beds loadings of 1.0 kg, 1.4 kg at a drying temperature of 90°C. The SFBD has shown excellent potential to dry the pepper with a relatively short drying time compared to the conventional method. Batch drying for the bed loads studied only took 3 hours of drying time only. It was found that bed higher bed loading of wet pepper requires longer drying time due to higher amount of moisture content in the bed. Four distinct regimes of operation were found during drying in the SFBD and these regimes offer flexibility of operation. The total bed pressure drop was relatively low during drying.

Fluidized bed selective pyrolysis of coal

Science.gov (United States)

Shang, Jer Y.; Cha, Chang Y.; Merriam, Norman W.

1992-01-01

The present invention discloses a process for the pyrolysis of coal which comprises the effective utilization of two zonal inclined fluidized beds, where said zones can be selectively controlled as to temperature and heating rate. The first zonal inclined fluidized bed serves as a dryer for crushed coal and additionally is controlled to selectively pyrolyze said coal producing substantially carbon dioxide for recycle use. The second zonal inclined fluidized bed further pyrolyzes the coal to gaseous, liquid and char products under controlled temperature and heating rate zones designed to economically integrate the product mix. The gas and liquid products are recovered from the gaseous effluent stream while the char which remains can be further treated or utilized in a subsequent process step.

Heat transfer and energy efficiency in infrared paper dryers

Energy Technology Data Exchange (ETDEWEB)

Pettersson, Magnus

1999-11-01

Infrared (IR) dryers are widely used in the paper industry, mainly in the production of coated paper grades. The thesis deals with various aspects of heat transfer and energy use in infrared heaters and dryers as employed in the paper industry. Both gas-fired and electric IR dryers are considered and compared. The thesis also provides an introduction to infrared heaters and infrared drying, including a review of recent literature in the field. The transport of thermal radiation inside a paper sheet was investigated and different IR dryers were compared in terms of their ability to transfer energy to the internal parts of a paper sheet. Although there were evident differences in the absorption of radiation between gas-fired and electric IR dryers, the distinction was found not to be as important as has generally been believed. The main differences appeared to be due to the choice of a one- or a two-sided dryer solution, rather than the spectral distributions emitted by the dryers. A method for evaluating the radiation efficiency of IR heaters was proposed. An electric IR heater was evaluated in the laboratory. The radiation efficiency of the heater was shown to be strongly dependent on the power level. The maximum efficiency, found at high power level, was close to 60 %. A procedure for evaluation of the total energy transfer efficiency of an infrared paper dryer was proposed and used in the evaluation of an electric IR dryer operating in an industrial coating machine. The efficiency of the dryer was roughly 40 %. A model for an electric IR heater was developed. The model includes non-grey radiative heat transfer between the different parts of the heater, as well as conduction in reflector material and convective cooling of the surfaces. Using IR module voltage as the only input, model predictions of temperatures and heat flux were found to agree well with experimental data both at steady state and under transient conditions. The model was also extended to include

Design and testing of solar dryers for processing food wastes

Energy Technology Data Exchange (ETDEWEB)

Nijmeh, M.N.; Ragab, A.S.; Emeish, M.S. [University of Jordan, Amman (Jordan). Mechanical Engineering Dept.; Jubran, B.A. [International Islamic University of Malaysia, Kaula Lumpur (Malaysia). Dept. of Mechanical Engineering

1998-12-01

This paper investigates the potential of using two solar dryers manufactured from locally available materials under Jordanian climatic conditions for drying food wastes for utilization as animal feed. The first dryer is a radiative-convective type, while the second is a solar boiler dryer. Tests were also conducted to investigate the nutritious values of the dried products and their suitability as animal feed. It was found from tests that the solar boiler dryer is more efficient than the radiative-convective dryer for producing animal feed in terms of both quality and quantity. The nutritious values of the end products from the dryers were found to be within the international recommended values used for feeding chickens. (author)

Adaptive control of paste drying in spouted bed using the GPC algorithm

Directory of Open Access Journals (Sweden)

Corrêa N.A.

2000-01-01

Full Text Available Spouted bed is an equipment reasonable investigated for drying of many and different materials ranging from granules to pastes and suspensions. This work presents an implementation and tests of an advanced control strategy (GPC on a spouted bed dryer. Water was used as the ideal paste for tests. A microcomputer PC-486 type was used to maintain humidity and temperature set points of air in the dryer by manipulating electric power of heat exchanger and paste feed flow rate. An instrumentation was set-up with different sensors, interface and final control elements for the process. The tests were carried out with pure water as ideal paste. Stability and performance analysis of the control strategy were accomplished. A stable controller was obtained which encouraged us to investigate this control strategy in the drying of other pastes too.

Operation experiences of biofuel dryers; Drifterfarenheter fraan aangtorkar och direkta roekgastorkar

Energy Technology Data Exchange (ETDEWEB)

Berge, Christian; Dejfors, Charlotte [AaF Energikonsult Stockholm AB (Sweden)

2000-01-01

A study regarding operation experiences of indirect steam dryers and direct flue gas dryers of biofuels has been conducted. In the study, plants with the two types of dryers have been visited and operational experiences have been gathered and analysed. Results show that the well proven technique with flue gas dryers has a higher availability than the steam dryers. Several plants have problem with the feeding and discharge systems. Material selection is very important to prevent corrosion. Indirect steam dryers have more environmental regulations than flue gas dryers because of the generated condensate from the fuel drying process. Future work should concentrate on material selections, refining the feeding and discharge systems and control system.

Low-energy collisions between electrons and BeD+

Science.gov (United States)

Niyonzima, S.; Pop, N.; Iacob, F.; Larson, Å; Orel, A. E.; Mezei, J. Zs; Chakrabarti, K.; Laporta, V.; Hassouni, K.; Benredjem, D.; Bultel, A.; Tennyson, J.; Reiter, D.; Schneider, I. F.

2018-02-01

Multichannel quantum defect theory is applied in the treatment of the dissociative recombination and vibrational excitation processes for the BeD+ ion in the 24 vibrational levels of its ground electronic state ({{X}}{}1{{{Σ }}}+,{v}{{i}}+=0\\ldots 23). Three electronic symmetries of BeD** states ({}2{{\\Pi }}, {}2{{{Σ }}}+, and {}2{{Δ }}) are considered in the calculation of cross sections and the corresponding rate coefficients. The incident electron energy range is 10-5-2.7 eV and the electron temperature range is 100-5000 K. The vibrational dependence of these collisional processes is highlighted. The resulting data are useful in magnetic confinement fusion edge plasma modeling and spectroscopy, in devices with beryllium based main chamber materials, such as ITER and JET, and operating with the deuterium-tritium fuel mix. An extensive rate coefficients database is presented in graphical form and also by analytic fit functions whose parameters are tabulated in the supplementary material.

PADDY DRYING IN MIXED ADSORPTION DRYER WITH ZEOLITE: DRYING RATE AND TIME ESTIMATION

Directory of Open Access Journals (Sweden)

Mochammad Djaeni

2013-11-01

Full Text Available Recently, the main problem of the rice stock and distribution in Indonesia is the quality degradation as indicated in unpleasant odor (smelly, stained, yellowness, and high percentage of broken rice. This is due to the low of paddy quality dried by from either direct sunlight or conventional fluidized bed dryer. As a result, the paddy cracks and breaks easily during milling in which causes the storage life being shorter as the enzymatic degradation by germ or fungi occurs. Air dehumidified with zeolite at drying medium temperature is potential to improve the quality of paddy. Zeolite is a material having high affinity to water vapor. In this case, the paddy and zeolite was mixed and fluidized with the air. The air will evaporate water from paddy, and at same time, the zeolite will adsorb water from air. Hence, the humidity of dryer can be kept low in which improves the driving force for drying. This work discusses the effect of presence of zeolite in the dryer, operational drying temperature, air velocity and relative humidity on drying rate of paddy. The results showed that increasing of zeolite as well as operational temperature increased the drying rate. In addition, using the model, the air dehumidification with zeolite and increase of air velocity can speed up drying time significantly at operational temperature below 80oC. This condition is very suitable for paddy drying since the quality degradation can be avoided.

Evaluation of a dryer in a steam generator

International Nuclear Information System (INIS)

Xue Yunkui; Liu Shixun; Guandao, Xie; Chen Junliang

1998-01-01

The hooked-vane-type dryer is used in vertical, natural circulation steam generators used in PWR-type nuclear power stations. it separates the fine droplets of water carried by steam so that the steam generator outlet steam moisture is below 0.25%. Such low moisture is demanded to ensure a safe and economic operation of the unit. The dryer is composed of hooked vanes and a draining structure. A series of tests to screen different designs were performed using air-water mixture. The paper presents the results of the investigation of the effect of the number of drainage hooks , the bending angle , distance between two adjacent vanes, and other geometrical parameters on the performance of a hooked-vane-type steam dryer. It indicates that the dryer still works effectively when the moisture of the steam at the dryer inlet changes in a wide range, and that the performance of the dryer is closely related to the geometry of the draining structure . On the basis of the results of this program, a draining structure with an original design was selected and it is presented in the paper. The performance of the selected draining structure is better than that of similar structures in China and abroad. (author)

Rotary drum dryers for coal slurries

Energy Technology Data Exchange (ETDEWEB)

Baunack, F

1983-04-01

The suitability, sizing and internal equipment of rotary drum dryers for high-ash coal slurries are discussed. Rotary dryers will handle also difficult slurries; by suitable drum sizes, lifter blades and chains not only high specific evaporation capacities can be achieved but also very high throughputs of up to 400 tons/h of finished product and high evaporation capacities of 60 tons/h.

Affordable Hybrid Heat Pump Clothes Dryer

Energy Technology Data Exchange (ETDEWEB)

TeGrotenhuis, Ward E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Butterfield, Andrew [Jabil, St. Petersburg, FL (United States); Caldwell, Dustin D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Crook, Alexander [Jabil, St. Petersburg, FL (United States)

2016-06-30

This project was successful in demonstrating the feasibility of a step change in residential clothes dryer energy efficiency by demonstrating heat pump technology capable of 50% energy savings over conventional standard-size electric dryers with comparable drying times. A prototype system was designed from off-the-shelf components that can meet the project’s efficiency goals and are affordable. An experimental prototype system was built based on the design that reached 50% energy savings. Improvements have been identified that will reduce drying times of over 60 minutes to reach the goal of 40 minutes. Nevertheless, the prototype represents a step change in efficiency over heat pump dryers recently introduced to the U.S. market, with 30% improvement in energy efficiency at comparable drying times.

CFD analysis for greenhouse effect solar dryer

International Nuclear Information System (INIS)

Wulandani, D.; Abdullah, K.; Hartulistiyoso, E.; Siswantara, I.

2006-01-01

Greenhouse Effect (GHE) solar dryer is a transparent wall structure, consists of absorber plate as solar heat collector, product holders (tray or batch) and fans to discharge moisture from the product. GHE solar dryer is one of the alternative dryer for the farmer and merchants to improve the quality of dried products. Direct sun drying is still popular choice by farmers because it is cheap and simple. However, the method is greatly dependent on the existence of solar irradiation and the product is contaminated very easily by pollution and dirt. The general constraint in designing artificial dryer is the problem of non-uniformity of final moisture content of product, especially for the cabinet of rack type dryer. This condition can be solved by providing uniform distribution of temperature, relative humidity (RH) and airflow velocity of the drying air. Therefore, in this study, such problem was approached by conducting flow simulation within the drying structure by using computational fluid dynamics (CFD) technology to determine the proper position of drying air inlet and outlet, location and capacity of the heat exchanger unit, the position and the capacity of the fan, to produce uniform distribution of the drying air temperature, RH and airflow velocity within the drying chamber.(Author)

Performance of modified greenhouse dryer with thermal energy storage

Directory of Open Access Journals (Sweden)

Om Prakash

2016-11-01

Full Text Available In this attempt, the main goal is to do annual performance, environomical analysis, energy analysis and exergy analysis of the modified greenhouse dryer (MGD operating under active mode (AM and passive mode (PM. Thermal storage is being applied on the ground of MGD. It is applied in three different ways namely barren floor, floor covered with black PVC sheet (PVC and Black Coated. Experimental study of dryers in no-load conditions reveals that floor covered with a black PVC sheet is more conducive for drying purpose than other floors. The MGD under AM is found to be more effective as compared to PM for tomato and capsicum, which are high moisture content crops. For medium moisture content crop (potato chips, both dryers show relatively similar drying performance. Crops dried inside the greenhouse dryer are found to be more nutrient than open sun dried crops. The payback period of the modified greenhouse dryer under passive mode is found to be 1.11 years. However, for the active mode of the modified greenhouse dryer is only 1.89 years. The embodied energy of the passive mode of the dryer is a 480.277 kWh and 628.73 kWh for the active mode of the dryer. The CO2 emissions per annum for passive and active mode greenhouse dryers are found to be 13.45 kg and 17.6 kg respectively. The energy payback time, carbon mitigation and carbon credit have been calculated based type of crop dried. The range of exergy efficiency is 29%–86% in MGD under PM and 30%–78% in the MGD under AM. The variation of Heat utilization factor (HUF for MGD under PM is 0.12–0.38 and 0.26–0.53 for MGD under AM. The range of co-efficient of performances (COP for MGD under PM is 0.55–0.87 and 0.58–0.73 for MGD under AM.

Experimental investigations of a chimney-dependent solar crop dryer

Energy Technology Data Exchange (ETDEWEB)

Afriyie, J.K.; Nazha, M.A.A.; Rajakaruna, H. [School of Engineering and Technology, De Montfort University, Queens Building, The Gateway, Leicester LE1 9BH (United Kingdom); Forson, F.K. [Department of Mechanical Engineering, Kwame Nkrumah University of Science and Technology, Kumasi (Ghana)

2009-01-15

An experimental investigation into the performance of a solar crop dryer with solar chimney and no air preheating is described. Tests were first performed on the cabinet dryer, using a normal chimney. The trials were repeated with a solar chimney. Still with the solar chimney, further trials were carried out with the roof of the drying chamber inclined further to form a tent dryer. The described tests include no-load tests for airflow rate measurements and drying tests, with cassava as the crop. Air velocities, temperatures, ambient relative humidity and the drop in crop moisture contents at different stages of the drying process are also presented. The effects of the various configurations described above on the drying process are deduced and discussed while comparing the experimental results with one another. In addition, the performance of the dryer in relation to other natural convection dryers is discussed. The results show that the solar chimney can increase the airflow rate of a direct-mode dryer especially when it is well designed with the appropriate angle of drying-chamber roof. However, the increase in flow rate only increases the drying rate when the relative humidity (RH) of the ambient air is below a certain mark (60% for cassava). (author)

Silk cocoon drying in forced convection type solar dryer

International Nuclear Information System (INIS)

Singh, Panna Lal

2011-01-01

The thin layer silk cocoon drying was studied in a forced convection type solar dryer. The drying chamber was provided with several trays on which the cocoons loaded in thin layer. The hot air generated in the solar air heater was forced into drying chamber to avoid the direct exposure of sunlight and UV radiation on cocoons. The drying air temperature varied from 50 to 75 o C. The cocoon was dried from the initial moisture content of about 60-12% (wb). The drying data was fitted to thin layer drying models. Drying behaviour of the silk cocoon was best fitted with the Wang and Singh drying model. Good agreement was obtained between predicted and experimental values. Quality of the cocoons dried in the solar dryer was at par with the cocoons dried in the conventional electrical oven dryer in term of the silk yield and strength of the silk. Saving of electrical energy was about 0.75 kWh/kg cocoons dried. Economic analysis indicated that the NPV of the solar dryer was higher and more stable (against escalation rate of electricity) as compare to the same for electrical oven dryer. Due to simplicity in design and construction and significant saving of operational electrical energy, solar cocoon dryer seems to be a viable option.

Development of an Active Solar Crop Dryer: Design Analysis and Performance Evaluation

International Nuclear Information System (INIS)

Itodo, I. N.; Adewole, A.M.; Edemaku, S.K.

2002-01-01

A forced convection indirect solar dryer powered by a PVC module was designed and evaluated. The performance of the dryer was poor; its drying rate, collector and system drying efficiency were 0.74 kg/day, 12% and 10% respectively. The dryer was redesigned and modified into a direct forced convection type- Its design analysis and performance evaluation was undertaken by drying mashed cassava. The drying rate, system drying collector and pick-up efficiencies were 1,6 kg/day (14%/day), 9%, 46% and 29% respectively. Comparatively, the drying rate for sun drying was 0.9 kg/day. The collector efficiency compared very well to the designed value of 48% and may not need further improvement. The pick-up efficiency also compared well with typical averages for this dryer type. The drying rate and system drying efficiency Indicate the need for further development of this dryer. Prediction equations were developed from the results of measured differences in collector, dryer and ambient air temperatures plotted on graphs and applying regression. It is recommended that the volumetric air-flow rate across the drying unit should he improved by affecting the tan speed and air inlet area of the dryer. The improved dryer will subsequently be compared to a natural convection dryer so that an appropriate dryer technology can be recommended for the rural small-scale farmers

Design and performance evaluation of a new hybrid solar dryer for banana

International Nuclear Information System (INIS)

Amer, B.M.A.; Hossain, M.A.; Gottschalk, K.

2010-01-01

A hybrid solar dryer was designed and constructed using direct solar energy and a heat exchanger. The dryer consists of solar collector, reflector, heat exchanger cum heat storage unit and drying chamber. The drying chamber was located under the collector. The dryer was operated during normal sunny days as a solar dryer, and during cloudy day as a hybrid solar dryer. Drying was also carried out at night with stored heat energy in water which was collected during the time of sun-shine and with electric heaters located at water tank. The efficiency of the solar dryer was raised by recycling about 65% of the drying air in the solar dryer and exhausting a small amount of it outside the dryer. Under Mid-European summer conditions it can raise up the air temperature from 30 to 40 deg. C above the ambient temperature. The solar dryer was tested for drying of ripe banana slices. The capacity of the dryer was to dry about 30 kg of banana slices in 8 h in sunny day from an initial moisture content of 82% to the final moisture content of 18% (wb). In the same time it reduced to only 62% (wb) moisture content in open sun drying method. The colour, aroma and texture of the solar dried products were better than the sun drying products.

Assessment of the bacterial contamination of hand air dryer in washrooms.

Science.gov (United States)

Alharbi, Sulaiman Ali; Salmen, Saleh Hussein; Chinnathambi, Arunachalam; Alharbi, Naiyf S; Zayed, M E; Al-Johny, Bassam O; Wainwright, Milton

2016-03-01

The present study was carried out, using standard techniques, to identify and count the bacterial contamination of hand air dryers, used in washrooms. Bacteria were isolated from the air flow, outlet nozzle of warm air dryers in fifteen air dryers used in these washrooms. Bacteria were found to be relatively numerous in the air flows. Bacterially contaminated air was found to be emitted whenever a warm air dryer was running, even when not being used for hand drying. Our investigation shows that Staphylococcus haemolyticus, Micrococcus luteus, Pseudomonas alcaligenes, Bacillus cereus and Brevundimonad diminuta/vesicularis were emitted from all of the dryers sampled, with 95% showing evidence of the presence of the potential pathogen S. haemolyticus. It is concluded that hot air dryers can deposit pathogenic bacteria onto the hands and body of users. Bacteria are distributed into the general environment whenever dryers are running and could be inhaled by users and none-users alike. The results provide an evidence base for the development and enhancement of hygienic hand drying practices.

Sustainability assessment of heat exchanger units for spray dryers

International Nuclear Information System (INIS)

Caglayan, Hasan; Caliskan, Hakan

2017-01-01

In this study, the sustainability assessment is performed to the system known as heat exchanger unit with spray dryer. The five-different dead state temperatures (0-5-10-15-20 °C) are considered. It is found that the heat exchanger has the highest energy efficiency (63.32%), while the overall system has the lowest one (5.56%). So, the combination of the spray dryer with the heat exchanger is more effective. On the other hand, the overall exergy efficiency of the system is lower than the heat exchanger and spray dryer for all of the dead state (environmental) temperatures. The exergy efficiency of the heat exchanger is inversely proportional to the dead state temperature, and the maximum rate is found as 49.65% at 0 °C. Furthermore, the exergy efficiencies of the spray dryer and overall system are directly proportional to the dead state temperatures, and the corresponding maximum rates are found to be 26.41% and 24.32% at 20 °C, respectively. Also, the exergy destruction is directly proportional to the dead state temperatures. The minimum and maximum exergy destruction rates are found at the dead state temperatures of 0 °C and 20 °C, respectively. Furthermore, the most sustainable system is found as the heat exchanger unit. - Highlights: • Thermodynamic analyses of industrial heat exchangers and spray dryers. • Sustainability of heat exchangers for spray dryers. • Dead state temperature effects on exergy efficiencies of heat exchangers and spray dryers.

solar dryer with biomass backup heater for drying fruits

African Journals Online (AJOL)

SOLAR DRYER WITH BIOMASS BACKUP HEATER FOR DRYING FRUITS: DEVELOPMENT AND PERFORMANCE ANALYSIS. ... Journal of Science and Technology (Ghana) ... Most solar dryers rely on only solar energy as the heat source.

The consequences of granulate heterogeneity towards breakage and attrition upon fluid-bed drying

NARCIS (Netherlands)

Nieuwmeyer, Florentine; Maarschalk, Kees van der Voort; Vromans, Herman

High-shear granulated lactose granulates were dried in it fluid-bed dryer at various conditions. Granules were characterized by water content and size analysis. It is shown that the drying process is very dynamic in terms of growth and breakage phenomena. Granular size heterogeneity, composition and

Assessment of the bacterial contamination of hand air dryer in washrooms

OpenAIRE

Alharbi, Sulaiman Ali; Salmen, Saleh Hussein; Chinnathambi, Arunachalam; Alharbi, Naiyf S.; Zayed, M.E.; Al-Johny, Bassam O.; Wainwright, Milton

2016-01-01

The present study was carried out, using standard techniques, to identify and count the bacterial contamination of hand air dryers, used in washrooms. Bacteria were isolated from the air flow, outlet nozzle of warm air dryers in fifteen air dryers used in these washrooms. Bacteria were found to be relatively numerous in the air flows. Bacterially contaminated air was found to be emitted whenever a warm air dryer was running, even when not being used for hand drying. Our investigation shows th...

Development and Evaluation of Solar Tunnel Dryer for Commercial Fish Drying

Science.gov (United States)

Mohod, A. G.; Khandetod, Y. P.; Shrirame, H. Y.

2014-01-01

The local practice of drying fish in open sun drying poses problems such as high moisture content, uncontrolled drying and contamination. These problems can be avoided by proper use of improved methods such as the solar tunnel dryer, which results in faster drying of fish. The semi cylindrical walk-in type natural convection solar tunnel dryer, having drying area of 37.5 m2 was developed and evaluated for the drying of fish products in comparison with the conventional method of open sun drying. The experiments were conducted without fish and with fish to evaluate the performance of solar tunnel dryer. The average rise in temperature inside the solar tunnel dryer was found to be 11.24 °C and 18.29 °C over the ambient temperature during no load test in winter and summer respectively. The average 28 % saving in time was observed for selected fish drying using solar tunnel dryer over open sun drying method with average drying efficiency of 19 %. The economics was calculated for drying of prawns ( Parapaeneopsis stylifera) by solar tunnel dryer and open sun drying system on the basis of business as a whole. The economics of the solar tunnel dryer is presented in term of Net present worth, Benefit-Cost Ratio, Payback period, Profitability index and Internal rate of return. The pay back period for solar tunnel dryer was found to be 2.84 years.

Theoretical and experimental drying of a cylindrical sample by applying hot air and infrared radiation in an inert medium fluidized bed

Directory of Open Access Journals (Sweden)

B. Honarvar

2012-06-01

Full Text Available Drying of a cylindrical sample in a fluidized bed dryer containing inert particles was studied. For this purpose, a pilot-scaled fluidized bed dryer was constructed in which two different heat sources, hot air and infrared radiation were applied, and pieces of carrot were chosen as test samples. The heat transfer coefficient for cylindrical objects in a fluidized bed was also measured. The heat absorption coefficient for carrot was studied. The absorption coefficient can be computed by dividing the absorbed heat by the carrot to the heat absorbed for the water and black ink. In this regard, absorbed heat values by the carrot, water and black ink were used A mathematical model was proposed based on the mass and heat transfer phenomena within the drying sample. The results obtained by the proposed model were in favorable agreement with the experimental data.

Neural network modeling of drying of rice in BAU-STR dryer

Science.gov (United States)

Alam, Md. Ashraful; Saha, Chayan Kumer; Alam, Md. Monjurul; Ashraf, Md. Ali; Bala, Bilash Kanti; Harvey, Jagger

2018-05-01

The experimental performance and artificial neural network modeling of rice drying in BAU-STR dryer is presented in this paper. The dryer consists of a biomass stove as a heat source, a perforated inner bin and a perforated outer bin with annular space for grains, and a blower (1 hp) to supply heated air. The dryer capacity was 500 kg of freshly harvested rice. Twenty experimental runs were conducted to investigate the experimental performance of the dryer for drying of rice. An independent multilayer neural network approach was used to predict the performance of the BAU-STR dryer for drying of rice. Ten sets of experimental data were used for training using back propagation algorithm and another ten sets of data were used for testing the artificial neural network model. The prediction of the performance of the dryer was found to be excellent after it was adequately trained. The statistical analysis showed that the errors (MSE and RMSE) were within and acceptable range of ±5% with a coefficient of determination (R2) of 99%. The model can be used to predict the potential of the dryer for different locations, and can also be used in a predictive optimal control algorithm.

Evaluation of hybrid solar – biomass dryer with no load

Directory of Open Access Journals (Sweden)

Yassen Tadahmun Ahmed

2014-07-01

Full Text Available Experimental study was carried out to investigate the performance of designed and fabricated hybrid solar-biomass dryer without load. The solar side was a natural convection mixed mode, while the biomass side was a hot air produced from a burner/gas to gas heat exchanger. The experiments have been conducted to test the dryer temperature, inlet and outlet relative humidity, outlet velocity, and biomass feeding rate. In the solar mode the maximum dryer temperature was 63°C. Behaviours of the velocity in the dryer was found to follow solar radiation available to the dryer. The velocity was in the range of 0.6 – 1.35 m/s through the 0.0176 m2 area of the outlet when the solar radiation was in the range of 150 – 880 W/m2. Two feeding rates of wood were used to investigate the dryer performance through the night. The results showed that at feeding rate 278 g/hr, the drying air mean temperature was 62 ºC. This temperature was more suitable than the measured drying air temperature at feeding rate 490 g/hr. Also the 62 °C drying environment is more stable and feasible for drying almost all types of products.

Effectiveness of a heat exchanger in a heat pump clothes dryer

Science.gov (United States)

Nasution, A. H.; Sembiring, P. G.; Ambarita, H.

2018-02-01

This paper deals with study on a heat pump clothes dryer coupled with a heat exchanger. The objective is to explore the effects of the heat exchanger on the performance of the heat pump dryer. The heat pump dryer consists of a vapor compression cycle and integrated with a drying room with volume 1 m3. The power of compressor is 800 Watt and the refrigerant of the cycle is R22. The heat exchanger is a flat plate type with dimensions of 400 mm × 400 mm × 400 mm. The results show the present of the heat exchanger increase the performance of the heat pump dryer. In the present experiment the COP, TP and SMER increase 15.11%, 4.81% and 58.62%, respectively. This is because the heat exchanger provides a better drying condition in the drying room with higher temperature and lower relative humidity in comparison with heat pump dryer without heat exchanger. The effectiveness of the heat exchanger is also high, it is above 50%. It is suggested to install a heat exchanger in a heat pump dryer.

New complex-dryers with RE for coatings

International Nuclear Information System (INIS)

Ge, G.

1998-01-01

Full text: The complex coating dryers are produced with good 2-Ethylhexanoic acid, rare earths and other metals. Simply using such a complex drier can get the total effect instead of the traditional dryers such as Co, Mn, Pb, Zn, Ca etc. It has advantages of saving quantity, decreasing cost, simplifying process, making the operation convenient, good quality, good stability and without Pb. Invention patent of China requisition number is 95119867.X

The impact of immersion protection requirements on hair dryer electrocutions in the USA.

Science.gov (United States)

Rodgers, Gregory B; Garland, Sarah

2012-12-01

To evaluate the effectiveness of the immersion protection requirements of a voluntary safety standard for portable handheld hair dryers in preventing electrocution deaths in the USA. The present work was an interrupted time series study design. Data on annual hair dryer-related electrocution deaths resulting from water contact were developed for the 1980-2007 study period. A multivariate Poisson regression model for rate data was used to evaluate the impact of the immersion protection requirements during the post-intervention period. The analysis controlled for the estimated number of hair dryers in use and the estimated number of US homes equipped with ground fault circuit interrupters, safety devices that would address hair dryer electrocutions even in the absence of the immersion protection requirements of the voluntary standard. The implementation of the 1987 and 1991 immersion protection requirements of the voluntary standard for portable handheld hair dryers was the intervention studied. The main outcome measure was the estimated reduction in the hair dryer electrocution rate associated with the immersion protection requirements of the voluntary standard. After controlling for covariates, the immersion protection requirements were estimated to reduce the rate of hair dryer immersion electrocution deaths by 96.6% (95% CI, 90.8% to 98.8%). This suggests the prevention of about 280 immersion electrocution deaths involving hair dryers during the post-intervention period (1987-2007). The immersion protection requirements of the voluntary safety standard for hair dryers have been highly effective in reducing hair dryer electrocutions.

New practical method for evaluation of a conventional flat plate continuous pistachio dryer

Energy Technology Data Exchange (ETDEWEB)

Kouchakzadeh, Ahmad [Agri Machinery Engineering, Ilam University, Ilam (Iran, Islamic Republic of); Tavakoli, Teymur [Agri Machinery Engineering, Tarbyat Modares University, Tehran (Iran, Islamic Republic of)

2011-07-15

Highlights: {yields} Evaluation of a conventional flat plate continuous pistachio dryer with a new feasible method. {yields} Using thermophysical properties of air and matter. {yields} This manner could be utilized in similar dryer for other agricultural products. {yields} Method shows the heat loss and power separately. -- Abstract: Testing a dryer is necessary to evaluate its absolute and comparative performance with other dryers. A conventional flat plate continuous pistachio dryer was tested by a new practical method of mass and energy equilibrium. Results showed that the average power consumption and heat loss in three tests are 62.13 and 18.99 kW, respectively. The ratio of heat loss on power consumption showed that the efficiency of practical pistachios flat plate dryer is about 69.4%.

New practical method for evaluation of a conventional flat plate continuous pistachio dryer

International Nuclear Information System (INIS)

Kouchakzadeh, Ahmad; Tavakoli, Teymur

2011-01-01

Highlights: → Evaluation of a conventional flat plate continuous pistachio dryer with a new feasible method. → Using thermophysical properties of air and matter. → This manner could be utilized in similar dryer for other agricultural products. → Method shows the heat loss and power separately. -- Abstract: Testing a dryer is necessary to evaluate its absolute and comparative performance with other dryers. A conventional flat plate continuous pistachio dryer was tested by a new practical method of mass and energy equilibrium. Results showed that the average power consumption and heat loss in three tests are 62.13 and 18.99 kW, respectively. The ratio of heat loss on power consumption showed that the efficiency of practical pistachios flat plate dryer is about 69.4%.

Development and performance evaluation of forced convection potato solar dryer

International Nuclear Information System (INIS)

Khan, M.A.; Sabir, M.S.; Iqbal, M.

2011-01-01

This research paper deals with the design development and testing of a forced convection solar dryer, for drying and converting to flour of high moisture content vegetables like potatoes. The angle of solar collector was made adjustable for the absorption of maximum solar radiation by the absorber plate. The air flow rate was controlled by adjustable gate valve to find the optimum flow rate for dehydration of the product. The penetration of solar radiation raised the temperature of the absorber plate of the dryer to 110 deg. C during the operation under stagnation or no load conditions. The maximum air temperature attained in the solar air heater, under this condition was 80 deg. C. The dryer was loaded with 12 Kg of blanched potato chips having an initial moisture content of 89.75%, and the final desired moisture content of 6.95% was achieved within five hours without losing the color of potato chips, while the moisture contents reduction was from 89.75% to 33.75% for five hours in open sun drying under shade. The drying cost for 1 Kg of potatoes was calculated as Rs. 245 and it was Rs. 329 in the case of an electric dryer. The life span of the solar dryer was assumed to be 20 years. The cumulative present worth of annual savings over the life of the solar dryer was calculated for blanched potato chips drying, and it turned out be Rs.163177.67/- which was much higher than the capital cost of the dryer (Rs. 25000). The payback period was calculated as 0.89 years, which was also very small considering the life of the system (20 years). (author)

MICROBIOLOGICAL CHARACTERISTICS OF THE AIR BLOWN BY WARM AIR HAND DRYERS

Directory of Open Access Journals (Sweden)

Recai OÐUR; Omer Faruk TEKBAS; Osman HANCI; Umut OZCAN

2005-02-01

Full Text Available The aim of the study was to determine the microbiological characteristics of air blown from warm air hand dryers, and to compare findings with the microbiological characteristics of indoor air in which the dryer settled. Air samples was taken from different public places (shopping centers, restaurants and hospitals and investigated for total viable counts, coagulase negative Staphylococcus, E. Coli, Staphylococcus aureus and enteric pathogens. There were differences between sampling indoor places for some of the microorganisms, but all of the air samples taken from dryers contained more microorganisms than indoor air, and the differences between hand dryers and indoor air were statistically significant (p<0.05 except for enteric pathogens. As a result it could be said that warm air hand dryers could be microbiological contamination sources in restrooms or the other places that they are used. [TAF Prev Med Bull 2005; 4(1.000: 1-7

Integration of thickener underflow into thermal dryer circuit. Final report

Energy Technology Data Exchange (ETDEWEB)

McClaine, A.W.; Breault, R.W.

1998-12-31

A large number of coal preparation plants in the United States are troubled with coal fines and associated plant operation problems. As part of their process, these plants use thermal dryers for producing product coal, cyclones for first-stage recovery of coal fines, and wet scrubbers for the second-stage removal of coal fines carry-over from the dryer exhaust gas. The first challenge for these plants is to recover the clean ultra-fine coal captured in the scrubbers rather than to dispose of it in settling ponds. The second challenge is to mitigate the over-dry fine coal dusting problems in the dryer product. Prior to the completion of this program, the difficulties of the first challenge involving the recovery and use of fine clean coal from the thermal dryer scrubber effluent had not been solved. The second challenge, controlling fine coal dusting, was previously met by applying a solution of surfactants and process water to the over-dry coal fraction. As a result of the demonstration provided by the performance of this program, the implementation of a simple process improvement, involving the use of a thickener in combination with a belt press, simultaneously solved both challenges: the de-dusting and the dryer scrubber effluent recovery issues. The objective of this project was to: (1) Use a clean coal thickener with a squeeze belt press to recover the ultra-fine coal in dryer scrubber effluent; (2) Demonstrate that the coal-water mixture (CWM) produced from scrubber sludge of a thermal dryer can be used as a dust suppressant. The thickener/belt press system has increased the production of JWRI Mine Number 4 by approximately 0.7%. This production increase was accomplished by recovering and re-using 3 metric tons/hr (3.3 tons/hr) of coal fines that were previously sent to holding ponds, returning this as a 50% CWM to de-dust the 430 metric tons/hr (470 tons/hr) of existing dryer production.

Inclined fluidized bed system for drying fine coal

Science.gov (United States)

Cha, Chang Y.; Merriam, Norman W.; Boysen, John E.

1992-02-11

Coal is processed in an inclined fluidized bed dryer operated in a plug-flow manner with zonal temperature and composition control, and an inert fluidizing gas, such as carbon dioxide or combustion gas. Recycled carbon dioxide, which is used for drying, pyrolysis, quenching, and cooling, is produced by partial decarboxylation of the coal. The coal is heated sufficiently to mobilize coal tar by further pyrolysis, which seals micropores upon quenching. Further cooling with carbon dioxide enhances stabilization.

Test and study for dryer used in steam generator

International Nuclear Information System (INIS)

Xue Yunkui; Liu Shixun; Xie Guandao; Chen Junliang

1994-10-01

Dryer used in steam generator is composed of hooked-vanes and draining structure. The influences of the number of drainage hooks on a hooked-vane, bending angle, distance between two adjacent hooked-vanes, etc. on separation effect are introduced. The improving process of draining structure is also described. The test indicates that the hooked-vanes type dryer allows to change inlet moisture in a large range and that the performance of the dryer is closely related to draining structure. A draining structure with original creation which is selected by the test is presented, its drainage effect is better than that of similar structures at home and abroad. (2 tabs., 21 figs.)

Processamento de achocolatado de cupuaçu por spray-dryer Cupuassu chocolate drink powder processed by spray-dryer

Directory of Open Access Journals (Sweden)

Suzana Caetano da Silva Lannes

2003-03-01

Full Text Available O achocolatado de cupuaçu é uma mistura do pó de cupuaçu, açúcar, aroma e outros ingredientes constantes da formulação. Este produto formulado foi processado por spray-dryer, gerando um produto seco, pulverizado e instantaneizado. O achocolatado acrescido de água (concentrado passa pelo spray-dryer formando glóbulos de pequeno diâmetro que são arrastados por uma corrente de ar quente. A rápida evaporação de líquido permite manter baixa a temperatura do ar na secagem, não afetando o produto. O pó de cupuaçu não dispersa prontamente em água devido ao seu conteúdo de óleo. Conseqüentemente, necessita-se de uma forma desengordurada para se obter instantaneização. A secagem por spray-dryer reúne as melhores condições de rendimento técnico em comparação com outros processos. Obtiveram rendimentos de processo acima de 20% e a instantaneização completa do produto.Cupuassu chocolate drink powder is a mixture of cupuassu powder, sugar, flavour and other ingredients of formulation. The product was processed by spray-dryer, leading a dry, pulverized and instantised product. The chocolate drink powder with water (concentrated pass through spray-dryer forming small diameter globules that are arrested by a hot air stream. The rapid evaporation allows keeping low temperature at drying air, and no affecting the product. The process is a set of better conditions of technique and economical efficiency in comparison to other process. Cupuassu powder does not disperse readily in water owing to its oil content. Consequently, a form of cocoa with the oil removed is needed to produce an acceptably instant drink. The results obtained were satisfactory, due to the complete instantisation of the product after processing.

Experimental Investigation on an Energy Efficient Solar Tunnel Dryer

OpenAIRE

M. R. Seshan Ram

2012-01-01

The research determines the effectiveness of the solar tunnel dryer developed and the product dried in the device is superior in quality and also it is compatible with branded products available in the market. The study also determines Acetamide as Phase Key words: Solar Tunnel Dryer, Acetamide as Phase Change Materials, Conversion into Thermal Energy, Thermocouple, and Pyranometer

Control Systems of Rubber Dryer Machinery Components Using Programmable Logic Control (PLC)

Science.gov (United States)

Hendra; Yulianto, A. S.; Indriani, A.; Hernadewita; Hermiyetti

2018-02-01

Application of programmable logic control (PLC) is widely used on the control systems in the many field engineering such as automotive, aviation, food processing and other industries [1-2]. PLC is simply program to control many automatic activity, easy to use, flexible and others. PLC using the ladder program to solve and regulated the control system component. In previous research, PLC was used for control system of rotary dryer machine. In this paper PLC are used for control system of motion component in the rubber dryer machinery. Component of rubber dryer machine is motors, gearbox, sprocket, heater, drying chamber and bearing. Principle working of rubber dryer machinery is wet rubber moving into the drying chamber by sprocket. Sprocket is driven by motors that conducted by PLC to moving and set of wet rubber on the drying chamber. Drying system uses greenhouse effect by making hanger dryer design in the form of line path. In this paper focused on motion control system motors and sensors drying rubber using PLC. The results show that control system of rubber dryer machinery can work in accordance control input and the time required to dry the rubber.

Current development of GHE solar dryer

International Nuclear Information System (INIS)

Kamaruddin Abdullah

2006-01-01

Field tests of the previous GHE solar dryer design had shown that the system can be used effectively to dry various agricultural and marine products. In order to improve further the performance of this dryer, particularly, to reduce dependency on electricity, mechanical energy and on heat generated from non-renewable energy sources, several new prototypes are now in the stage of preliminary testing. These new systems were designed to dry granular products using vibrated drums and for non-granular products such as chili, sliced vegetables and fish products using vibrating racks. The hybrid renewable energy system for drying accommodate Savonius windmill for air moving device as well as vibration generator and simple biomass stove as auxiliary heating unit

Modeling and simulation of milk emulsion drying in spray dryers

Directory of Open Access Journals (Sweden)

V. S. Birchal

2005-06-01

Full Text Available This work aims at modeling and simulating the drying of whole milk emulsion in spray dryers. Drops and particles make up the discrete phase and are distributed into temporal compartments following their residence time in the dryer. Air is the continuous and well-mixed phase. Mass and energy balances are developed for each phase, taking into account their interactions. Constitutive equations for describing the drop swelling and drying mechanisms as well as the heat and mass transfer between particles and hot air are proposed and analyzed. A set of algebraic-differential equations is obtained and solved by specific numerical codes. Results from experiments carried out in a pilot spray dryer are used to validate the model developed and the numerical algorithm. Comparing the simulated and experimental data, it is shown that the model predicts well the individual drop-particle history inside the dryer as well as the overall outlet air-particle temperature and humidity.

Herbs drying using a heat pump dryer

Energy Technology Data Exchange (ETDEWEB)

Fatouh, M.; Metwally, M.N.; Helali, A.B.; Shedid, M.H. [Department of Mechanical Power Engineering, Faculty of Engineering at El Mattaria, Helwan University, P.O. Box 11718, Masaken El-Helmia, Cairo (Egypt)

2006-09-15

In the present work, a heat pump assisted dryer is designed and constructed to investigate the drying characteristics of various herbs experimentally. R134a is used as a working fluid in the heat pump circuit during the experimental work. Experiments have been conducted on Jew's mallow, spearmint and parsley. The effects of herb size, stem presence, surface load, drying air temperature and air velocity on the drying characteristics of Jew's mallow have been predicted. Experimental results show that a high surface load of 28kg/m{sup 2} yields the smallest drying rate, while the drying air with temperature of 55{sup o}C and velocity of 2.7m/s achieves the largest drying rate. A maximum dryer productivity of about 5.4kg/m{sup 2}h is obtained at the air temperature of 55{sup o}C, air velocity of 2.7m/s and dryer surface load of 28kg/m{sup 2}. It was found that small size herbs without stem need low specific energy consumption and low drying time. Comparison of the drying characteristics of different herbs revealed that parsley requires the lowest specific energy consumption (3684kJ/kg{sub H{sub 2}O}) followed by spearmint (3982kJ/kg{sub H{sub 2}O}) and Jew's mallow (4029kJ/kg{sub H{sub 2}O}). Finally, dryer productivity has been correlated in terms of surface load, drying air velocity and drying air temperature. (author)

30 CFR 77.307 - Thermal dryers; location and installation; general.

Science.gov (United States)

2010-07-01

... where the heat, sparks, flames, or coal dust from the system might cause a fire or explosion. (b... LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Thermal Dryers § 77.307 Thermal dryers; location and installation; general...

Hand dryer noise in public restrooms exceeds 80 dBA at 10 ft (3 m

Directory of Open Access Journals (Sweden)

Shari Salzhauer Berkowitz

2015-01-01

Full Text Available High airflow hand dryers are found in many public restrooms today. These dryers offer quick and clean hand drying, and are seen as being an environment-friendly alternative to paper towels. However, many new hand dryers are loud, exposing individuals using the facilities as well as those employees who clean the facilities to potentially dangerous noise. Prolonged exposure to high levels of occupational noise can cause damage to hair cells in the cochlea, resulting in varying degrees of noise-induced hearing loss. This study examined the intensity (in dBA of the noise produced by the air dryers in campus restrooms. Hand dryer peak and average noise was measured with a sound level meter at 2.5 ft, 5 ft, and 10 ft from the dryer. Noise measurements did not decrease as predicted by the inverse-square law, probably because of the reverberative surfaces found in the restrooms. The small sample of hand dryers tested was mostly found to be producing more noise than the manufacturer claimed they would; indeed, none of the dryers would be safe for an 8-h workday exposure. While hand dryers do reduce paper trash, they pose as a different sort of hazard to our environment and population.

Tropical field performance of dual-pass PV tray dryer

Science.gov (United States)

Iskandar, A. Noor; Ya'acob, M. E.; Anuar, M. S.

2017-09-01

Solar Photovoltaic technology has become the preferable solution in many countries around the globe to solve the ever increasing energy demand of the consumers. In line with the consumer need, food processing technology has huge potentials of integration with the renewable energy resources especially in drying process which consumes the highest electricity loads. Traditionally, the solar dryer technology was applied in agriculture and food industries utilizing the sun's energy for drying process, but this is highly dependable on the weather condition and surrounding factors. This work shares some field performance of the new design of portable dual-pass PV tray dryer for drying crops in an enclosed system. The dual-pass PV tray dryer encompass a lightweight aluminium box structure with dimensions of 1.1m (L) x 0.6m (W) x 0.2m (H) and can hold a load capacity of 300g - 3kg of crop depending on the types of the crops. Experiments of field performance monitoring were conducted in October -November 2016 which justifies a considerable reduction in time and crops quality improvement when using the dual-pass PV tray dryer as compared to direct-sun drying.

Solar dryer with thermal storage and biomass-backup heater

Energy Technology Data Exchange (ETDEWEB)

Madhlopa, A. [Department of Physics and Biochemical Sciences, Malawi Polytechnic, P/Bag 303, Blantyre 3 (Malawi); Ngwalo, G. [Department of Mechanical Engineering, Malawi Polytechnic, P/Bag 303, Blantyre 3 (Malawi)

2007-04-15

An indirect type natural convection solar dryer with integrated collector-storage solar and biomass-backup heaters has been designed, constructed and evaluated. The major components of the dryer are biomass burner (with a rectangular duct and flue gas chimney), collector-storage thermal mass and drying chamber (with a conventional solar chimney). The thermal mass was placed in the top part of the biomass burner enclosure. The dryer was fabricated using simple materials, tools and skills, and it was tested in three modes of operation (solar, biomass and solar-biomass) by drying twelve batches of fresh pineapple (Ananas comosus), with each batch weighing about 20 kg. Meteorological conditions were monitored during the dehydration process. Moisture and vitamin C contents were determined in both fresh and dried samples. Results show that the thermal mass was capable of storing part of the absorbed solar energy and heat from the burner. It was possible to dry a batch of pineapples using solar energy only on clear days. Drying proceeded successfully even under unfavorable weather conditions in the solar-biomass mode of operation. In this operational mode, the dryer reduced the moisture content of pineapple slices from about 669 to 11% (db) and yielded a nutritious dried product. The average values of the final-day moisture-pickup efficiency were 15%, 11% and 13% in the solar, biomass and solar-biomass modes of operation respectively. It appears that the solar dryer is suitable for preservation of pineapples and other fresh foods. Further improvements to the system design are suggested. (author)

Experimental silo-dryer-aerator for the storage of soybean grains

Directory of Open Access Journals (Sweden)

Paulo C. Coradi

Full Text Available ABSTRACT This study aimed to verify the capacity of silo-dryer-aerator prototype equipment operating as a silo-storage-aerator for soybean quality analysis. Soybeans with water content of 17% (wet basis – w.b. were dried and stored in a silo-dryer-aerator system that was designed using a drying chamber, four independent storage cells, and a static capacity of 164 kg. Another batch of grains was stored in a silo-storage-aerator with a capacity of 1,200 kg. The experiment was set up in a completely randomized factorial 5 × 4 experimental design including five grain batches stored after being dried at 30, 40, and 50 °C (mixed grains were dried at three temperatures in the silo-dryer-aerator cells and one mixed grain batch stored in the silo-storage-aerator system under ambient air conditions for four storage times (zero, one, two, and three months. There was no difference between the grains stored in the silo-dryer-aerator and silo-storage-aerator at the end of the three-month storage in terms of the physico-chemical quality. The storage time associated with drying at 50 °C caused a reduction in the physical-chemical quality of the grains. The silo-dryer-aerator system was presented as a possible alternative to store soybean (Glycine max L. grains.

Machine & electrical double control air dryer for vehicle air braking system

Science.gov (United States)

Zhang, Xuan; Yang, Liu; Wang, Xian Yan; Tan, Xiao Yan; Wang, Wei

2017-09-01

As is known to all, a vehicle air brake system, in which usually contains moisture. To solve the problem, it is common to use air dryer to dry compressed air effectively and completely remove the moisture and oil of braking system. However, the existing air dryer is not suitable for all commercial vehicles. According to the operational status of the new energy vehicles in the initial operating period, the structure design principle of the machine & electric control air dryer is expounded from the aspects of the structure and operating principle, research & development process.

Model-Based Energy Efficiency Optimization of a Low-Temperature Adsorption Dryer

NARCIS (Netherlands)

Atuonwu, J.C.; Straten, G. van; Deventer, H.C. van; Boxtel, A.J.B. van

2011-01-01

Low-temperature drying is important for heat-sensitive products, but at these temperatures conventional convective dryers have low energy efficiencies. To overcome this challenge, an energy efficiency optimization procedure is applied to a zeolite adsorption dryer subject to product quality. The

Low cost solar dryer for fish

African Journals Online (AJOL)

Administrator

Department of Electrical and Other Energy Sources, College of Agricultural Engineering and Technology, DBSKKV, ... The average solar energy ranged between 450 - 500 ..... classification and selection of dryers, In Handbook of industrial.

76 FR 22324 - Energy Conservation Program: Energy Conservation Standards for Residential Clothes Dryers and...

Science.gov (United States)

2011-04-21

... standards, the current standards for room air conditioners and clothes dryers, and the history of the... Residential Clothes Dryers and Room Air Conditioners AGENCY: Office of Energy Efficiency and Renewable Energy... equipment, including residential clothes dryers and room air conditioners. EPCA also requires the U.S...

Energy Efficient Clothes Dryer with IR Heating and Electrostatic Precipitator

Energy Technology Data Exchange (ETDEWEB)

Weaver, Stanton [GE Global Research, Niskayuna, NY (United States)

2017-12-12

The project goal was to develop a revolutionary energy saving technology for residential clothes drying. The team developed an IR (infrared) heating system and NESP (Nebulizer and Electro-Static Precipitator) for integration into a ventless clothes dryer. The proposed technology addresses two of the major inefficiencies in current electric vented dryers by providing effective energy transfer for the removal of the water and recapture of the vapor latent heat. The IR heaters operating in the mid wave (2.5-10um) are very efficient as they target the 3-micron peak absorption of the water molecule. This allows direct energy absorption, unlike conventional element heaters where heat is transferred by convection. The low power NESP removes water vapor from the exhausted stream and recaptures the latent heat in the ESP (Electro-Static Precipitator) exchanger section. This allows the warm dry air to be recirculated back into the drum for additional efficiency savings. The remaining majority of the dryer hardware stays the same. Summing the efficiency gain from the two subcomponents we anticipated the EF (Efficiency Factor) to exceed the goal of 4.04. EF is obtained by dividing the weight (lbs) of water removed by the energy (kWhr) used, where the test load size is 8.45 lbs of bone dry clothing wetted to 57.5% or 4.8lbs of water, and dried to a remaining moisture content of 2.5-5%. Additional benefits include not having to recondition (heat or cool) the large amounts of make-up air to replace the air exhausted by a vented dryer. It was anticipated that the NESP/heat exchanger would be the most challenging and highest risk element in the program. Therefore, the team focused their efforts during Phase 1 of the program on the design, construction, testing, and optimization of the NESP/heat exchanger. At the end Phase 1, the team compared the performance of the NESP/heat exchanger with the system level requirements and made a Go/No-Go decision on proceeding with the second

Assessment of differences between products obtained in conventional and vacuum spray dryer

Directory of Open Access Journals (Sweden)

Fernanda de Melo RAMOS

Full Text Available Abstract In this work, an experimental unit of a vacuum spray dryer was built. This prototype attempted to combine the advantages of freeze-drying (drying at low temperatures due to vacuum and spray drying (increase of surface area aiming the improvement of heat transfer efficiency. Maltodextrin solutions were dried in the vacuum operated equipment and in conventional spray dryer. The vacuum spray dryer system allowed obtaining powder at low temperatures due to the lowering of pressure conditions (2-5 kPa inside the drying chamber. The products obtained in the two systems were characterized and compared for particle size distribution, moisture content, water activity, bulk density and solubility in water. The processes yields were also evaluated and compared. The vacuum spray dryer system allowed the production of larger, more soluble and less dense particles than those obtained in the conventional configuration of the equipment, resulting in drier and, therefore, with lower water activity particles. Thus, the use of the vacuum spray dryer as a drying technique may be an alternative for the production of powder rich in thermosensitive compounds.

The Design And Development Of Solar Maize Dryer With Subsidiary ...

African Journals Online (AJOL)

A solar Dryer with a subsidiary heating source for drying maize seed is designed and constructed. The dryer is made up a solar collector (heat source), the drying chamber (Product storage), and a subsidiary heating source (local oil). The plant when put in operation by expositing it to the solar rays, is capable of attaining a ...

ENERGY STAR Certified Residential Clothes Dryers

Data.gov (United States)

U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 1.1 ENERGY STAR Program Requirements for Clothes Dryers that are effective as of January...

A greenhouse type solar dryer for small-scale dried food industries: Development and dissemination

Energy Technology Data Exchange (ETDEWEB)

Janjai, Serm [Solar Energy Research Laboratory, Department of Physics, Faculty of Science, Silpakorn University, Nakhon Pathom 73000 (Thailand)

2012-07-01

In this study, a greenhouse type solar dryer for small-scale dried food industries was developed and disseminated. The dryer consists of a parabolic roof structure covered with polycarbonate sheets on a concrete floor. The system is 8.0m in width, 20.0m in length and 3.5m in height, with a loading capacity about 1,000kg of fruits or vegetables. To ensure continuous drying operation, a 100kW-LPG gas burner was incorporated to supply hot air to the dryer during cloudy or rainy days. Nine 15-W DC fans powered by three 50-W PV modules were used to ventilate the dryer. This dryer was installed for a small-scale food industry at Nakhon Pathom in Thailand to produce osmotically dehydrated tomato. To investigate its performance, the dryer was used to dry 3 batches of osmotically dehydrated tomato. Results obtained from these experiments showed that drying air temperatures in the dryer varied from 35 C to 65 C. In addition, the drying time for these products was 2-3 days shorter than that of the natural sun drying and good quality dried products were obtained. A system of differential equations describing heat and moisture transfers during drying of osmotically dehydrated tomato was also developed. The simulated results agreed well with the experimental data. For dissemination purpose, other two units of this type of dryer were constructed and tested at two locations in Thailand and satisfactory results were obtained.

Design and Evaluation of Solar Grain Dryer with a Back-up Heater

OpenAIRE

K.S. Tonui; E.B.K. Mutai; D.A. Mutuli; D.O. Mbuge; K.V. Too

2014-01-01

The aim of the study was to design and construct a solar grain dryer integrated with a simple biomass burner using locally available materials. This was to address the limitations of the natural sun drying for example drying exposure, liability to pests and rodents, over-dependence on sun and escalated cost of mechanical dryers. This became beneficial especially in reducing post-harvest losses as well as helping in the preservation of agricultural product. The dryer is composed of solar colle...

75 FR 27504 - Substantial Product Hazard List: Hand-Held Hair Dryers

Science.gov (United States)

2010-05-17

... immersion during their use. Section 15(a) of the CPSA defines ``substantial product hazard'' to include, a....'' Hand-held hair dryers routinely contain open-coil heating elements that are, in essence, uninsulated..., bathtub, or lavatory). The proposed rule would define ``hand-held hair dryer'' as ``an electrical...

24 CFR 3280.708 - Exhaust duct system and provisions for the future installation of a clothes dryer.

Science.gov (United States)

2010-04-01

...(a)(1) through (5). (c) Provisions for future installation of electric clothes dryers. When wiring is... for the future installation of a clothes dryer. 3280.708 Section 3280.708 Housing and Urban... duct system and provisions for the future installation of a clothes dryer. (a) Clothes dryers. (1) All...

75 FR 7987 - Energy Conservation Standards for Residential Clothes Dryers and Room Air Conditioners: Public...

Science.gov (United States)

2010-02-23

... Conservation Standards for Residential Clothes Dryers and Room Air Conditioners: Public Meeting and... conservation standards for residential clothes dryers and room air conditioners; the analytical framework..., Mailstop EE-2J, Public Meeting for Residential Clothes Dryers and Room Air Conditioners, EERE-2007-BT-STD...

Performance of a Forced-Convection Greenhouse Dryer for Fish Drying

Directory of Open Access Journals (Sweden)

Martunis Martunis

2013-04-01

Full Text Available ABSTRACT. This research present experimental performance of a forced convection greenhouse dryer for drying of fish. The greenhouse dryer was installed at Aceh province, Indonesia. It has a concrete floor with the area of 6×4 m2. The roof of dryer is built in semi-cylindrical shape and covered with transparent polycarbonate sheets. Two axial flow fans powered by a 50-watt solar cell module was used to generate forced convection for ventilating the dryer.To investigate its performance, the dryer was used to dry two batches of fish. The Results showed that to dry 50 kg fish with initial moisture 68 % required 11 hours. Incontrast, to dry the same amount of fish using sun drying take a time about 2 days. The air temperature inside greenhouse dryer at noon in the clear day was 45-55°C. Kinerja Pengering Rumah Kaca Dengan Metode Konveksi Paksa Untuk Pengeringan Ikan ABSTRAK. Penelitian ini memperlihatkan hasil percobaan terhadap kinerja pengering rumah kaca dengan metode konveksi udara secara paksa pada pengeringan ikan. Penelitian pengering rumah kaca ini dilakukan di Propinsi Aceh, Indonesia. Pengering ini berlantaikan beton dengan luas sebesar 6x4 m2. .Atapnya dibuat berbentuk semi-selinder dan ditutup dengan lembaran plastik transparan berbahan polikarbonat. Dua buah kipas dengan aliran udara secara aksial dipasang dengan sumber daya berasal dari panel surya sebesar 50 Watt dan dipakai untuk menghasilkan konveksi udara paksa pada ventilasi pengering. Untuk menginvestigasi kinerja rumah kaca ini, pengering ini digunakan untuk mengeringkan dua tumpukan ikan. Hasilnya menunjukkan bahwa untuk mengeringkan sebanyak 50 kg ikan dengan kadar air awalnya sebesar 68% membutuhkan waktu selama 11 jam. Sebaliknya, dengan menggunakan sinar matahari secara langsung, untuk mengeringkan ikan dengan jumlah yang sama, maka waktu yang dibutuhkan lebih lama yaitu sekitar 2 hari. Suhu udara di dalam rumah pengering tepat pada siang hari yang cerah berkisar antara 45

Construction of a flexible pilot dryer for products such as biofuels and iron ore pellets; Uppbyggnad av flexibel pilottork foer produkter som biobraenslen och jaernmalmspellets

Energy Technology Data Exchange (ETDEWEB)

Karlsson, Erik; Truedsson, Ida; Stenstroem, Stig

2009-02-15

Drying of different products is an operation that requires large amounts of energy in Sweden, a compilation from 2006 indicates a total use of over 32 TWh of thermal energy. A more energy efficient drying process can thus result in significant savings of energy for this process. The interest to use biofuels for heating purposes increases with increasing energy prices and thus also the interest to dewater and dry these products. Often an excess of low-value heat (flue gases, warm water etc.) is available and it would be desirable to use these streams for drying of different products. The goal in this project has been to carry out two subtasks: A Rebuild and modernise the old pilot dryer at the department so that it can be used for studies of drying kinetics for different products in a bed or as separate particles. B Perform a number of drying experiments with two representative bio-fuels which can be used for evaluation of different proposals for drying of these products. The results will mainly be of interest for companies handling biofuels in the forestry sector, for LKAB producing iron ore pellets and for manufacturers of industrial dryers. The constructed pilot dryer can be used for studies of drying kinetics of different types of products such as bark, wood chips, materials in the form of pellets such as iron ore pellets or wood pellets and foods. If the drying cell is designed so that fine particulate materials are not entrained with the gas flow, products such as municipal or industrial sludges can also be handled in the dryer. The results indicate specific energy use figures of between 2500 and 3000 kJ/kg evaporated water, both for different fractions of bark and independently if the origin of the bark was Vaeroe or Iggesund. The drying time to reach a dry matter content of 60 % for a bed with a thickness of 20 cm and an air velocity of 1 m/s is about 5000 seconds at an air temperature of 50 deg C. It increases to 15000 seconds to reach a dry matter content

Cementitious Spray Dryer Ash-Tire Fiber Material for Maximizing Waste Diversion

Directory of Open Access Journals (Sweden)

Charles E. Riley

2011-01-01

Full Text Available Spray dryer absorber (SDA material, also known as spray dryer ash, is a byproduct of coal combustion and flue gas scrubbing processes that has self-cementing properties similar to those of class C fly ash. SDA material does not usually meet the existing standards for use as a pozzolan in Portland cement concrete due to its characteristically high sulfur content, and thus unlike fly ash, it is rarely put to beneficial use. This paper presents the results of a study with the objective of developing beneficial uses for SDA material in building materials when combined with tire fiber reinforcement originating from a recycling process. Specifically, spray dryer ash was investigated for use as the primary or even the sole binding component in a mortar or concrete. This study differs from previous research in that it focuses on very high contents of spray dryer ash (80 to 100 percent in a hardened product. The overarching objective is to divert products that are normally sent to landfills and provide benefit to society in beneficial applications.

76 FR 971 - Energy Conservation Program for Consumer Products: Test Procedures for Clothes Dryers and Room...

Science.gov (United States)

2011-01-06

.... Detergent Specifications for Clothes Dryer Test Cloth Preconditioning 5. Changes To Reflect Current Usage... conservation standard; (3) updated detergent specifications for clothes dryer test cloth preconditioning; (4... detergent specifications for clothes dryer test cloth preconditioning; (7) update the references to external...

DESIGN AND THERMAL PERFORMANCE OF THE SOLAR BIOMASS HYBRID DRYER FOR CASHEW DRYING

Directory of Open Access Journals (Sweden)

Saravanan Dhanuskodi

2014-12-01

Full Text Available Drying of Cashew nut to remove testa is one of the most energy-intensive processes of cashew nut process industry. For this reason a hybrid dryer consisting of a solar flat plate collector, a biomass heater and a drying chamber is designed and fabricated. 40 kg of Cashew nut with initial moisture of 9 % is used in the experiment. The performance test of the dryer is carried out in two modes of operation: hybrid-forced convection and hybrid-natural convection. Drying time and drying efficiency during these two modes of operation are estimated and compared with the sun drying. The system is capable of attaining drying temperature between 50º and 70ºC. In the hybrid forced drying, the required moisture content of 3% is achieved within 7 hours and the average system efficiency is estimated as 5.08%. In the hybrid natural drying, the required moisture content is obtained in 9 hours and the average system efficiency is 3.17%. The fuel consumption during the drying process is 0.5 kg/hr and 0.75 kg/hr for forced mode and natural mode, respectively. The drying process in the hybrid forced mode of operation is twice faster than the sun drying. The dryer can be operated in any climatic conditions: as a solar dryer on normal sunny days, as a biomass dryer at night time and as a hybrid dryer on cloudy days. Based on the experimental study, it is concluded that the developed hybrid dryer is suitable for small scale cashew nut farmers in rural areas of developing countries.

Heat-pump tumble dryers; Waermepumpen-Tumbler

Energy Technology Data Exchange (ETDEWEB)

Bluemig, N.; Gatter, R.

2004-07-01

Commonly available tumble dryers with air-vented or condenser systems in combination with electrical heating have a high specific energy consumption and never fulfil the requirements for Energy Label Class A (<= 0.55 kWh/kg.). The development of a tumbler with a heat pump system has enabled a reduction of almost 50% in the specific energy consumption. In addition to ecological aspects, this means that a significant reduction in energy costs is achieved as well as a beneficial effect on room climate. Other considerations taken into account in the development of the 6.5 kg tumbler were: (i) Compact modular design; integration of the heat pump in the appliance casing; (ii) Long operating life without clogging-up of the heat exchanger by fluff; (iii) Stable process throughout the drying in ambient temperatures of up to 35 {sup o}C. Process stability in particular presented a tough challenge. The solution came in the form of an additional booster condenser that prevents overheating of the compressor towards the end of the process when only negligible amounts of energy are being carried away as a result of the low residual moisture in the laundry. It proved possible to reduce the specific power consumption to less than 0.4 kWh/kg and the leak rate to less 30 %. Thanks to the compact, modular design, the heat pump could be integrated in a housing which has the same size as a conventional 6.5 kg dryer. Clogging-up of the heat exchanger surfaces with fluff was prevented by a multi-stage cascade filtration system. With this heat pump dryer it has been possible for the very first time to develop to series production and launch an appliance in the up to 6.5 kg category that not only fulfils the requirements of Energy Label Class A but also offers a serious alternative to conventional tumble dryers thanks to its compact design, operating safety and ease of operation. Future development opportunities lie in more cost-effective production of the heat pump module, shortening of

PIV measurements of flow structures in a spray dryer

DEFF Research Database (Denmark)

Meyer, Knud Erik; Velte, Clara Marika; Ullum, Thorvald

2011-01-01

Stereoscopic Particle Image Velocimetry (PIV) measurements are made in horizontal planes in a simplified scale model of a spray dryer using water as fluid. The sample rate was sufficient to resolve phenomena at lower frequencies. Data reveal asymmetric velocity fields in both mean fields and dyna......Stereoscopic Particle Image Velocimetry (PIV) measurements are made in horizontal planes in a simplified scale model of a spray dryer using water as fluid. The sample rate was sufficient to resolve phenomena at lower frequencies. Data reveal asymmetric velocity fields in both mean fields...

Review on advanced of solar assisted chemical heat pump dryer for agriculture produce

International Nuclear Information System (INIS)

Fadhel, M.I.; Sopian, K.; Daud, W.R.W.; Alghoul, M.A.

2011-01-01

Over the past three decades there has been nearly exponential growth in drying R and D on a global scale. Improving of the drying operation to save energy, improve product quality as well as reduce environmental effect remained as the main objectives of any development of drying system. A solar assisted chemical heat pump dryer is a new solar drying system, which have contributed to better cost-effectiveness and better quality dried products as well as saving energy. A solar collector is adapted to provide thermal energy in a reactor so a chemical reaction can take place. This reduces the dependency of the drying technology on fossil energy for heating. In this paper a review on advanced of solar assisted chemical heat pump dryer is presented (the system model and the results from experimental studies on the system performance are discussed). The review of heat pump dryers and solar assisted heat pump dryer is presented. Description of chemical heat pump types and the overview of chemical heat pump dryer are discussed. The combination of chemical heat pump and solar technology gives extra efficiency in utilizing energy. (author)

Usage of Heat Pump Dryer in Food Drying Process and Apple Drying Application

Directory of Open Access Journals (Sweden)

Gökhan Gürlek

2015-12-01

Full Text Available In Turkey, drying is achieved natural method by spreading out the material on the ground. In this way, there are many disadvantages like low quality and hygienic problems. The resulting loss of food quality in the dried products may have effect negatively trade potential and economical worth. For preventing the deterioration of the materials different types of drying methods have been developed. Low energy consumption applications are important for drying industry besides high product quality. For this purpose, heat pump dryer is gaining importance day by day in drying applications. In this study, the working principle of the heat pump dryer, heat pump types in the drying process and the heat pump dryer performance criteria will be considered. An example of application will be described using obtained results from apple drying operation that is conducted in the heat pump dryer.

Numerical analysis on centrifugal compressor with membrane type dryer

Science.gov (United States)

Razali, M. A.; Zulkafli, M. F.; Mat Isa, N.; Subari, Z.

2017-09-01

Moisture content is a common phenomenon in industrial processes especially in oil and gas industries. This contaminant has a lot of disadvantages which can lead to mechanical failure DEC (Deposition, Erosion & Corrosion) problems. To overcome DEC problem, this study proposed to design a centrifugal compressor with a membrane type dryer to reduce moisture content of a gas. The effectiveness of such design has been analyzed in this study using Computational Fluid Dynamics (CFD) approach. Numerical scheme based on multiphase flow technique is used in ANSYS Fluent software to evaluate the moisture content of the gas. Through this technique, two kind of centrifugal compressor, with and without membrane type dryer has been tested. The results show that the effects of pressure on dew point temperature of the gas change the composition of its moisture content, where high value lead more condensation to occur. However, with the injection of cool dry gas through membrane type dryer in the centrifugal compressor, the pressure and temperature of moisture content as well as mass fraction of H2O in centrifugal compressor show significant reduction.

Conceptual design of pilot scale solar dryer for seaweeds

International Nuclear Information System (INIS)

Marta Abreu de Las Villas (Cuba))" data-affiliation=" (Departamento de Ingeniería Química, Facultad de Química y Farmacia, Universidad Central Marta Abreu de Las Villas (Cuba))" >Roche-Delgado, Liset; Marta Abreu de Las Villas (Cuba))" data-affiliation=" (Departamento de Ingeniería Química, Facultad de Química y Farmacia, Universidad Central Marta Abreu de Las Villas (Cuba))" >Hernández-Touset, Juan Pedro; Marta Abreu de Las Villas (Cuba))" data-affiliation=" (Departamento de Ingeniería Química, Facultad de Química y Farmacia, Universidad Central Marta Abreu de Las Villas (Cuba))" >García-Rodríguez, Agustín

2017-01-01

Drying algal biomass with the use of solar radiation is an economical and environmentally compatible option. The aim of this work was to design an indirect solar dryer with natural air circulation for seaweeds drying. The equipment supports discrete quantities of wet biomass and is protected from environmental situations that may damage the product; it does not need electricity to operate and the construction and operating costs are low. This comprises a collector made of copper plates for air circulation, heated by solar radiation, a glass cover and drying trays with a wooden structure. The dryer was designed to obtain 0, 3 kg / day of dry biomass. The methodology allows construction and operation of a flexible solar dryer in different operating conditions for research on seaweeds. Correspondingly with environmental and operating conditions the design included estimation of drying time, the determination of drying area, number of trays, air flow from the collector to the trays, collector sizing; heat transfer area, temperature reached by air and collector efficiency. (author)

Natural convection solar dryer with biomass back-up heater

Energy Technology Data Exchange (ETDEWEB)

Bena, B.; Fuller, R.J. [University of Melbourne (Australia). Faculty of Engineering

2002-07-01

A direct-type natural convection solar dryer and a simple biomass burner have been combined to demonstrate a drying technology suitable for small-scale processors of dried fruits and vegetables in non-electrified areas of developing countries. From a series of evaluation trials of the system, the capacity of the dryer was found to be 20-22kg of fresh pineapple arranged in a single layer of 0.01-m-thick slices. The overall drying efficiency of the unit was calculated to be {approx} 9%. During the same trial, the drying efficiency of the solar component alone was found to be 22%. Other trials estimated the efficiency of the burner in producing useful heat for drying to be 27%. Key features of the biomass burner were found to be the addition of thermal mass on the upper surface, an internal baffle plate to lengthen the exhaust gas exit path and a variable air inlet valve. Further modifications to further improve the performance of both the solar and biomass components of the dryer are suggested. (author)

Thin layer drying characteristics of curry leaves (Murraya koenigii in an indirect solar dryer

Directory of Open Access Journals (Sweden)

Vijayan Selvaraj

2017-01-01

Full Text Available In this work, the thin layer drying characteristics of curry leaves (Murraya koenigii has been studied in an indirect forced convection solar dryer with constant air mass flow rate of 0.0636 kg/s. Twelve thin layer drying models were tested for its suitability to describe the drying characteristics of curry leaves. The dryer has reduced the initial moisture content of curry leaves from 67.3% (wet basis to the final moisture content of 4.75% (wet basis in 3.5 hours. The pickup efficiency of indirect solar dryer for drying curry leaves was varied between 4.9% and 23.02%. Based on the statistical parameters, the Modified Henderson and Pabis model and Wang and Singh model were selected for predicting the drying characteristics of curry leaves. The payback period for the solar dryer was evaluated as 8 months, which is found to be much lower when compared with the entire life span of 15 years. The payback evaluation confirms that the solar dryer is economically viable in rural applications.

Design, Development and Performance Evaluation of a Small Scale Solar Assisted Paddy Dryer for on Farm Processing

Directory of Open Access Journals (Sweden)

Sidrah Ashfaq

2016-04-01

Full Text Available With the continued escalation in population growth and the expansion of international food trade and demand of high quality product for food security at low cost has created considerable interest in the development of new post-harvest technologies. This is particularly important for developing countries where post-harvest losses of cereals are between 10-20% and of fruits and vegetables as high as 20- 100% A new solar assisted paddy dryer with central air distribution model (along the length of drying chamber has been developed. Due to this distinct feature of the dryer high drying rate was achieved during the drying processes .Other components of the dryer are perforated drying chamber, blower and flat plat solar air collector. Dryer was evaluated using 100kg of freshly harvested paddy at 23.78% moisture content (wb. Performance evaluation results showed that the mean drying rate of the solar assisted paddy dryer was 0.87kg/hr per for every 100kg, whereas 0.46kg/hr was the sun drying rate comparatively. The faster drying rate of the dryer reveals its suability to dry the paddy for its safe storage moisture content rapidly. By using the solar assisted paddy dryer, approximately 50% saving in time was also achieved as compared with the traditional sun drying method. Solar assisted paddy dryer took 10hr for drying the 100kg paddy up to 14%, while sun drying method dried paddy up to 13.89% in 19 hours. Cost analysis also showed that, by using solar assisted paddy dryer we candry good quality paddy at low cost as compared with the open sun drying method. For development of agriculture in the rural areas, commercial size of the solar assisted paddy dryer can be amplified and produced at community level.

Application of Constrained Linear MPC to a Spray Dryer

DEFF Research Database (Denmark)

Petersen, Lars Norbert; Poulsen, Niels Kjølstad; Niemann, Hans Henrik

2014-01-01

In this paper we develop a linear model predictive control (MPC) algorithm for control of a two stage spray dryer. The states are estimated by a stationary Kalman filter. A non-linear first-principle engineering model is developed to simulate the spray drying process. The model is validated against...... experimental data and able to precisely predict the temperatures, the air humidity and the residual moisture in the dryer. The MPC controls these variables to the target and reject disturbances. Spray drying is a cost-effective method to evaporate water from liquid foods and produces a free flowing powder...

Energetic and economic optimization of solar tunnel dryers with a photovoltaic driven fan

International Nuclear Information System (INIS)

Muehlbauer, W.; Mayer, R.A.; Esper, A.; Reisinger, L.; Linckh, G.; Hensel, O.

1992-02-01

In the recent years the solar tunnel dryer has been used successfully for drying several agricultural products in tropical and subtropical countries. Up to now the dissemination has been limited to electrified areas. Objective of this work has been the improvement of the thermal performance of the tunnel dryer due to a optimization of the plastic film solar air heater as well as optimization work in point of fluid dynamic view to reduce the power requirement of the blower. To improve the efficiency of the blower optimization work had been done by investigating several blower wheels, dc-motors and actuation systems. A PV-System was designed according to these requirements to test the long term behaviour. The remarkable features of the newly designed solar tunnel dryer are the low power requirement for driving the blower and a high efficiency of the actuation. In the range of a power requirement of 80 - 100 W a blower with an efficiency of 48% is now available. The theoretical power requirement of the solar tunnel dryer could be reduced to 11 W. From economic point of view the use of the solar tunnel dryer is possible. (orig.) With 3 refs., 15 tabs., 49 figs [de

A dedicated on-line detecting system for auto air dryers

Science.gov (United States)

Shi, Chao-yu; Luo, Zai

2013-10-01

According to the correlative automobile industry standard and the requirements of manufacturer, this dedicated on-line detecting system is designed against the shortage of low degree automatic efficiency and detection precision of auto air dryer in the domestic. Fast automatic detection is achieved by combining the technology of computer control, mechatronics and pneumatics. This system can detect the speciality performance of pressure regulating valve and sealability of auto air dryer, in which online analytical processing of test data is available, at the same time, saving and inquiring data is achieved. Through some experimental analysis, it is indicated that efficient and accurate detection of the performance of auto air dryer is realized, and the test errors are less than 3%. Moreover, we carry out the type A evaluation of uncertainty in test data based on Bayesian theory, and the results show that the test uncertainties of all performance parameters are less than 0.5kPa, which can meet the requirements of operating industrial site absolutely.

Critical Point Dryer: Tousimis 916B Series C

Data.gov (United States)

Federal Laboratory Consortium — Description:CORAL Name: Critical Point DryerThis system utilizes CO 2to dry fragile suspended and floating structures Specifications / Capabilities:Wafer size up to...

40 CFR 60.734 - Monitoring of emissions and operations.

Science.gov (United States)

2010-07-01

... clay vibrating grate dryer, a bentonite rotary dryer, a diatomite flash dryer, a diatomite rotary... owner or operator of a ball clay rotary dryer, a diatomite rotary dryer, a feldspar fluid bed dryer, a...

Energy and exergy analysis of industrial fluidized bed drying of paddy

International Nuclear Information System (INIS)

Sarker, Md. Sazzat Hossain; Ibrahim, Mohd Nordin; Abdul Aziz, Norashikin; Punan, Mohd Salleh

2015-01-01

This paper presents energy and exergy analysis of industrial fluidized bed paddy drying. The maximum design capacity of the dryer was 22 t/h. Existing energy and exergy models developed applying the First and Second law of Thermodynamics are employed to estimate the amounts of energy used, the ratios of energy utilization, magnitude of exergy losses and exergy efficiencies during the drying process. The analysis shows that energy usage and (EUR) energy utilization ratios vary between 38.91 kJ/s to 132.00 kJ/s and 5.24–13.92 %, respectively while exergy efficiency vary from 46.99 to 58.14%. A simple exergy balance reveals that only 31.18–37.01 % exergy are utilized for drying of paddy and the remaining large amount of exergy are wasted. Exergy can be increased through providing sufficient insulation on dryer body and recycling the exhaust air which need to be studied further for investigating the economic feasibility. - Highlights: • Energy and exergy analysis of industrial fluidized bed paddy drying are presented. • Energy usage varies from 38.91 kJ/s to 132.00 kJ/s. • Energy usage ratio is found to vary between 5.24 and 13.38%. • Exergy efficiency varies from 41.30 to 58.14%. • Only 31.18–37.01 % exergy are utilized in the paddy drying system

75 FR 67623 - Approval and Promulgation of Air Quality Implementation Plans; Illinois; Volatile Organic...

Science.gov (United States)

2010-11-03

... Implementation Plan for Abbott Laboratories AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule... site-specific rulemaking for certain of Abbott Laboratories' (Abbott) tunnel dryers and fluid bed... rulemaking for certain of Abbott Laboratories' (Abbott) tunnel dryers and fluid bed dryers. (i) Incorporation...

Characterization and drying of caja bagasse (Spondias mombin L. in a tray dryer using a factorial planning

Directory of Open Access Journals (Sweden)

Andréia Souto da Silva

2012-03-01

Full Text Available The caja (Spondias mombin L. is used in the manufacture of ice-cream, jams, pulps, beverages being also consumed in natura. One of the most important procedures in food conservation is drying, considering that most fresh fruits contain approximately 80% of water. Food drying is used to obtain two basic aspects: (1 the economic factor; in the shipping and handling of the product; (2 at the manipulation; once dried and grinded, the material is rehydrated, at desirable levels, to formulate a new product as in ice cream, jams, yoghurts and drinks and may also be added to pasta, biscuits and other industrialized products. The aim of this study was to investigate the kinetics of caja bagasse drying in a fixed-bed tray dryer, using central composite factorial planning. The following factors were evaluated: temperature (55, 65 and 75 ºC, dryer inlet air velocity (3.2, 4.6 and 6.0 m.s-1 and cake thickness (0.8, 1.2 and 1.6 cm where the response of the considered variable was caja bagasse moisture content (b.s. and the results showed that the main effects and their interactions were significant at a 95% confidence level being the best condition obtained at temperature of 75 ºC, velocity of 6.0 m.s-1 and cake thickness of 0.8 cm.

Biogas utilization for drying sweet potato chips by using infrared dryer

Science.gov (United States)

Sriharti, Rahayuningtyas, Ari; Susanti, Novita Dwi; Sitompul, Rislima Febriani

2017-11-01

This study aims to utilize biogas, that produced from organic waste, as fuel for infrared dryers. The digester was dome type, which made from fiberglass, 5.5 m3 capacities, gas container made from soft PVC, 5.6 m3 capacities. The infrared dryer was household scale which have dimension 2000 mm x 2000 mm x 2000 mm, it is consist of 2 racks, which have size 1500 mm x 500 mm x 1400 mm, and consist of 44 baking pans (600 mm X 400 mm x 30 mm), the dryer has 36 kg of capacity. The parameters observed include ambient temperature, temperature inside the digester, pH value, biogas production, drying room temperature, moisture content of sweet potato and biogas consumption for drying. Infrared dryer is used to dry the sweet potato slices thickness of 2 mm with total amount 12 kg, at room temperature dryer ± 60 °C. The results showed that the average biogas production was 1.335 m3 per day, at a temperature of 26 - 35 °C and the neutral pH value was 6.99 - 7.7. 12 kg of sweet potato sliced dried for 4 hours, the initial moisture content of 79.68 % decreased to 8.98 %, the consumption of biogas used 4,952 m3. The final result of drying process of sweet potato slices of 3.5 kg, there was a shrinkage of 70.83 %. Characterization of sweet potato slices is 3 % protein, 0,6 % fat, 94 % carbohydrate and 2 % ash. These sweet potato can be used as flour for cookies and cake raw materials, the use of sweet potato flour can reach 50 - 100 %.

Design, development and performance testing of a new natural convection solar dryer

Energy Technology Data Exchange (ETDEWEB)

Pangavhane, D.R. [K.K. Wagh College of Engineering, Nashik (India). Department of Mechanical Engineering; Sawhney, R.L.; Sarsavadia, P.N. [Devi Ahilya Vishwa Vidhyalaya, Indore (India). School of Energy and Environmental Studies

2002-06-01

Mechanical drying of agricultural products is an energy consuming operation in the post-harvesting technology. Greater emphasis is given to using solar energy sources in this process due to the high prices and shortages of fossil fuels. For these purposes, a new natural convection solar dryer consisting of a solar air heater and a drying chamber was developed. This system can be used for drying various agricultural products like fruits and vegetables. In this study, grapes were successfully dried in the developed solar dryer. The qualitative analysis showed that the traditional drying, i.e. shade drying and open sun drying, dried the grapes in 15 and 7 days respectively, while the solar dryer took only 4 days and produced better quality raisins. (author)

Development of a Mini-Freeze Dryer for Material-Sparing Laboratory Processing with Representative Product Temperature History.

Science.gov (United States)

Obeidat, Wasfy M; Sahni, Ekneet; Kessler, William; Pikal, Michael

2018-02-01

The goal of the work described in this publication was to evaluate a new, small, material-sparing freeze dryer, denoted as the "mini-freeze dryer or mini-FD", capable of reproducing the product temperature history of larger freeze dryers, thereby facilitating scale-up. The mini-FD wall temperatures can be controlled to mimic loading procedures and dryer process characteristics of larger dryers. The mini-FD is equipped with a tunable diode laser absorption spectroscopy (TDLAS) water vapor mass flow monitor and with other advanced process analytical technology (PAT) sensors. Drying experiments were performed to demonstrate scalability to larger freeze dryers, including the determination of vial heat transfer coefficients, K v . Product temperature histories during K v runs were evaluated and compared with those obtained with a commercial laboratory-scale freeze dryer (LyoStar II) for sucrose and mannitol product formulations. When the mini-FD wall temperature was set at the LyoStar II band temperature (- 20°C) to mimic lab dryer edge vials, edge vial drying in the mini-FD possessed an average K v within 5% of those obtained during drying in the LyoStar II. When the wall temperature of the mini-FD was set equal to the central vial product temperature, edge vials behaved as center vials, possessing a K v value within 5% of those measured in the LyoStar II. During both K v runs and complete product freeze drying runs, the temperature-time profiles for the average edge vials and central vial in the mini-FD agreed well with the average edge and average central vials of the LyoStar II.

Simulation of energetic- and exergetic performance of microwave-assisted fluidized bed drying of soybeans

International Nuclear Information System (INIS)

Ranjbaran, M.; Zare, D.

2013-01-01

The performance of microwave-assisted fluidized bed drying of soybeans was simulated (using a previously validated mathematical model) and analyzed based on the first- and second law of thermodynamics. The energy and exergy analysis were carried out for several drying conditions. The effects of inlet air temperature, microwave power density, bed thickness and inlet air velocity on the efficiencies and inefficiencies of drying process have been simulated and discussed. Generally, application of microwave energy during fluidized bed drying enhanced the exergy efficiency of drying process. However, the results showed that it was more efficient not to apply microwave energy at the first stage of fluidized bed drying process. The application of higher levels of drying air temperature led in higher exergy efficiencies. The values of mean relative deviations for the predictions of efficiencies and inefficiencies of drying process were less than 14%, compared with those calculated using experimental data. - Highlights: • Introducing a mathematical model to predict the efficiency of microwave-assisted fluidized bed dryers. • Energy and exergy analysis in microwave-assisted fluidized bed drying of grains. • Providing practical recommendations for efficient use of microwave power during drying

Steam generator with integral downdraft dryer

Energy Technology Data Exchange (ETDEWEB)

Hochmuth, F.W.

1992-02-01

On June 30, 1989, a financial assistance award was granted by the United State Department of Energy, the purpose of which was to study and evaluate the technical aspect, the economic viability, and commercial possibilities of a new furnace design for burning high moisture cellulose type fuels. The new design is an invention by F.W. Hochmuth, P.Eng. and has received United States Patents Nos. 4,480, 557 and 4,502,397. It was conceived as a method to improve the general operation and efficiency of waste wood burning boilers, to avoid the use of stabilizing fuels such as oil or gas, and to reduce objectionable stack emissions. A further objective was to obtain such benefits at relatively low cost by integrating all new material requirements within the furnace itself thereby avoiding the need for costly external equipment. The proposed integral down-draft dryer avoids the use of external dryer systems that are very expensive, have high power consumption, and require a large amount of maintenance. This document provides the details of this invention.

PERFORMANCE ASSESSMENT OF SOLAR DRYER WITH INDIRECT HEATING

Directory of Open Access Journals (Sweden)

Boryana Brashlyanova

2014-03-01

Full Text Available The performed tests were designed to identify and analyze the parameters of drying in a authors model solar dryer. They to be the basis for constructing of an improved model. Drying was carried out in a pilot model solar dryer with prunes in two cycles. Both samples were run under steady sunshine in outdoor air temperature ranging between 20-22°C in the morning and 33-35°C in the early afternoon hours. Depending on the ambient conditions, the drying temperature was found in the range of 30 to 50°C. The dried samples had a water activity Aw> 0.9, due to which the storage is at -18°C. The duration of the drying process of prunes was inconstant and lasted from 2 to 3 days, depending on the final moisture content of the product and the external temperature, humidity, and intensity of solar radiation. The obtained two products intermediate moisture prunes, in addition to direct human consumption could be used as a base for incorporation into other products. Prunes with intermediate moisture content 40% could be consumed directly at ambient temperature or after freezing and tempering at -6 to -5ºC. Based on the established parameters we are to design and produce an improved solar dryer model that allows better utilization of heat and shortening the process duration.

Development of heat pump and infrared-convective dryer and performance analysis for stale bread drying

International Nuclear Information System (INIS)

Aktaş, Mustafa; Şevik, Seyfi; Aktekeli, Burak

2016-01-01

Highlights: • Investigation of stale bread drying behaviors by developing the HPD and IRD. • New techniques for the HP and IR dryers are proposed and found to be efficient. • Evaluations on potential uses low temperature applications of the dryers were reported. • 35.6% of energy saving was provided by heat recovery device. • The overall system efficiency of HPD was calculated as 13–60%. - Abstract: This experimental study aims to develop a heat pump dryer (HPD) and an infrared dryer (IRD) also the comparative empirical analyses of these two methods and to analyze the drying kinetic of stale bread sliced 15 mm thickness and effectiveness on the drying kinetics of the stale bread of dryers. Dryers have been developed by using different techniques such as heat recovery unit, proportional control (PC) of drying air temperature, simultaneous control of the relative humidity–temperature–air flow rate, water cycle dehumidifier and closed-loop cycle to increase the drying efficiency of industrial drying applications. The highest coefficient of performance of the whole heat pump system (COP_w_s_,_H_P) was calculated as 3.7 and drying efficiencies of the IRD and HPD systems were calculated as 39% and 25%, respectively. When the HPD and IRD systems were compared in terms of drying time and energy consumption, it was observed that the IRD system did not only shortened the drying time up to 69%, but also decreased the energy consumption of the system by 43.2%. Based on the obtained results the effective moisture diffusivity (D_e) was calculated in the range from 8.3 × 10"−"8 to 3.2 × 10"−"7 m"2/s and mass transfer coefficient (h_m) was varied from 1.17 × 10"−"5 to 4.52 × 10"−"5 m/s. It was concluded that both dryers have significant effect in reduction of water content; the relative humidity controlled HPD can be applied efficiently for dryers and the dried stale bread can be reused as bread crumb by food industry.

Slurry spray distribution within a simulated laboratory scale spray dryer

International Nuclear Information System (INIS)

Bertone, P.C.

1979-01-01

It was found that the distribution of liquid striking the sides of a simulated room temperature spray dryer was not significantly altered by the choice of nozles, nor by a variation in nozzle operating conditions. Instead, it was found to be a function of the spray dryer's configuration. A cocurrent flow of air down the drying cylinder, not possible with PNL's closed top, favorably altered the spray distribution by both decreasing the amount of liquid striking the interior of the cylinder from 72 to 26% of the feed supplied, and by shifting the zone of maximum impact from 1.0 to 1.7 feet from the nozzle. These findings led to the redesign of the laboratory scale spray dryer to be tested at the Savannah River Plant. The diameter of the drying chamber was increased from 5 to 8 inches, and a cocurrent flow of air was established with a closed recycle. Finally, this investigation suggested a drying scheme which offers all the advantages of spray drying without many of its limitations

Proposal for the award of a contract for the design, supply, installation, commissioning and testing at CERN of eight helium dryer units for the LHC

CERN Document Server

2001-01-01

This document concerns the award of a contract for the design, supply, installation, commissioning and testing at CERN of eight helium dryer units for the LHC. Following a market survey carried out among 42 firms in ten Member States, a call for tenders (IT-2722/LHC/LHC) was sent on 10 August 2000 to seven firms and three consortia, consisting of two firms each, in seven Member States. By the closing date, CERN had received five tenders from three firms and two consortia in five Member States. The Finance Committee is invited to agree to the negotiation of a contract with the firm COSMI (IT), the lowest bidder fulfilling the technical requirements, for the design, supply, installation, commissioning and testing at CERN of eight helium dryer units for a total amount of 3 514 779 euros, (5 307 329 Swiss francs), not subject to revision, with options for additional equipment for heating the adsorber bed and additional heat exchanger/condenser equipment, for an additional amount of 80 081 euros (120 923 Swiss fra...

Performance Analysis of a Solar Dryer Equipped with a Recycling Air System and Desiccant Chamber

Directory of Open Access Journals (Sweden)

M.H Aghkhani

2013-09-01

Full Text Available Drying is a high energy consuming process. Solar drying is one of the most popular methods for dehydration of agricultural products. In the present study, the performance of a forced convection solar dryer equipped with recycling air system and desiccant chamber was investigated. The solar dryer is comprised of solar collector, drying chamber, silica jell desiccant chamber, air ducts, fan and measuring and controlling system. Drying rate and energy consumption in three levels of air temperature (40, 45 and 50 oC and two modes of drying (with recycling air and no-recycling with open duct system were measured and compared. The results showed that increasing the drying air temperature decreased the drying time and increased the energy consumption in the mode of non-recycling air system. The dryer efficiency and drying rate were better in the mode of recycling air system than open duct system. The highest dryer efficiency was obtained from drying air temperature of 50 oC and the mode of recycling air system. In general, the efficiency of solar collector and the highest efficiency of the dryer were 0.34 and 0.41, respectively.

Performance of a chevron steam dryer for removal of lead-bismuth droplets

International Nuclear Information System (INIS)

Dostal, Vaclav; Yusibani, Elin; Takahashi, Minoru

2005-01-01

An analysis was performed of a chevron type steam dryer with a trap for the removal of lead-bismuth droplets from steam leaving the Water Boiling Direct Contact Lead or Lead-Bismuth Cooled Reactor. The Lagrangian method was used and is described here. The steam flow field was developed using a CFD code FrontFlow/Red. The simulated dryer performance results were compared to a simple theoretical model from literature. The simulation shown that droplets down to 6 microns in diameter can be completely removed by the steam dryer, which is better than reported earlier in literature. A discrepancy with the theoretical model was found for larger droplets (5 to 10 microns in diameter), where the theoretical model predicted lower removal efficiency. The discrepancy is attributed to be installation of the trap, which is not included in this theoretical model. Some droplets of 1 and 0.5 microns were removed in the dryer as well, which indicates the potential for the fine droplet removal if the trap design is carefully optimized. The investigation of the effect of initial droplet velocity shown that the removal efficiency increases with the increase of the positive velocity components. For larger droplets the effect of initial velocity was found to be minuscule. (author)

Performance studies of solar tunnel dryer for drying aonla (Embilica Officinalis) pulp

International Nuclear Information System (INIS)

Seveda, M. S.

2012-01-01

A solar tunnel dryer was constructed and evaluated the performance for drying aonla pulp. The dryer consists of a transparent UV stabilized plastic covered solar collector cum drying unit. Evaluation parameters are air temperature, solar insolation, moisture content, relative humidity and airflow rate. A minimum of 111.18 m 2 solar collector area is required to dry a batch 1000 kg aonla pulp in 16 hours (two days drying period). The initial and final moisture content considered were 424.93 and 10.08% dry basis, respectively. It was observed that on an average 43 per cent of higher temperature was obtained in solar tunnel dryer over the ambient temperature. The results obtained during the test period denoted that the maximum gained energy occurred at 13 o'clock hour and then gradually declined since the maximum solar radiation occurred at this time. (author)

A study of particle motion in rotary dryer

Directory of Open Access Journals (Sweden)

M. H. Lisboa

2007-09-01

Full Text Available The purpose of this work was to study the performance of a rotary dryer in relation to number of flights. In this work an equationing was proposed to calculate the area used by the solids in two-segment flights of with any angle between the segments. From this area, the flight holdup and the length of fall of the particles were calculated for different angle positions and the results obtained were compared to experimental values. The results show an increase in dryer efficiency with the increase in number of flights up to a limit value, for ideal operational conditions. The experimental data on average residence time were compared to results obtained by calculations using equations proposed in the literature. The equation proposed for predicting flight holdup and length of fall of particles generated very accurate estimations.

Performance of a solar dryer using hot air from roof-integrated solar collectors for drying herbs and spices

Energy Technology Data Exchange (ETDEWEB)

Janjai, S.; Tung, P. [Silpakorn University, Pathom (Thailand). Dept. of Physics

2005-11-01

A solar dryer for drying herbs and spices using hot air from roof-integrated solar collectors was developed. The dryer is a bin type with a rectangular perforated floor. The bin has a dimension of 1.0 m x 2.0 m x 0.7 m. Hot air is supplied to the dryer from fiberglass-covered solar collectors, which also function as the roof of a farmhouse. The total area of the solar collectors is 72 m{sup 2}. To investigate its performance, the dryer was used to dry four batches of rosella flowers and three batches of lemon-grasses during the year 2002-2003. The dryer can be used to dry 200 kg of rosella flowers and lemon-grasses within 4 and 3 days, respectively. The products being dried in the dryer were completely protected from rains and insects and the dried products are of high quality. The solar air heater has an average daily efficiency of 35% and it performs well both as a solar collector and a roof of a farmhouse. (author)

Study on effectiveness of continuous solar dryer integrated with desiccant thermal storage for drying cocoa beans

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Sari Farah Dina

2015-03-01

Full Text Available The main objective is to assess effectiveness of continuous solar dryer integrated with desiccant thermal storage for drying cocoa beans. Two type of desiccants were tested, molecular sieve 13× (Na86 [(AlO286·(SiO2106]·264H2O as an adsorbent type and CaCl2 as an absorbent type. The results revealed that during sunshine hours, the maximum temperature within the drying chamber varied from 40 °C to 54 °C. In average, it was 9–12 °C higher than ambient temperature. These temperatures are very suitable for drying cocoa beans. During off-sunshine hours, humidity of air inside the drying chamber was lower than ambient because of the desiccant thermal storage. Drying times for intermittent directs sun drying, solar dryer integrated with adsorbent, and solar dryer integrated with absorbent were 55 h, 41 h, and 30 h, respectively. Specific energy consumptions for direct sun drying, solar dryer integrated with adsorbent, and solar dryer integrated with absorber were 60.4 MJ/kg moist, 18.94 MJ/kg moist, and 13.29 MJ/kg moist, respectively. The main conclusion can be drawn here is that a solar dryer integrated with desiccant thermal storage makes drying using solar energy more effective in term of drying time and specific energy consumption.

Quantitative real-time monitoring of dryer effluent using fiber optic near-infrared spectroscopy.

Science.gov (United States)

Harris, S C; Walker, D S

2000-09-01

This paper describes a method for real-time quantitation of the solvents evaporating from a dryer. The vapor stream in the vacuum line of a dryer was monitored in real time using a fiber optic-coupled acousto-optic tunable filter near-infrared (AOTF-NIR) spectrometer. A balance was placed in the dryer, and mass readings were recorded for every scan of the AOTF-NIR. A partial least-squares (PLS) calibration was subsequently built based on change in mass over change in time for solvents typically used in a chemical manufacturing plant. Controlling software for the AOTF-NIR was developed. The software collects spectra, builds the PLS calibration model, and continuously fits subsequently collected spectra to the calibration, allowing the operator to follow the mass loss of solvent from the dryer. The results indicate that solvent loss can be monitored and quantitated in real time using NIR for the optimization of drying times. These time-based mass loss values have also been used to calculate "dynamic" vapor density values for the solvents. The values calculated are in agreement with values determined from the ideal gas law and could prove valuable as tools to measure temperature or pressure indirectly.

Temperature Control System for Mushroom Dryer

Science.gov (United States)

Wibowo, I. A.; Indah, Nur; Sebayang, D.; Adam, N. H.

2018-03-01

The main problem in mushroom cultivation is the handling after the harvest. Drying is one technique to preserve the mushrooms. Traditionally, mushrooms are dried by sunshine which depends on the weather. This affects the quality of the dried mushrooms. Therefore, this paper proposes a system to provide an artificial drying for mushrooms in order to maintain their quality. The objective of the system is to control the mushroom drying process to be faster compared to the natural drying at an accurate and right temperature. A model of the mushroom dryer has been designed, built, and tested. The system comprises a chamber, heater, blower, temperature sensor and electronic control circuit. A microcontroller is used as the controller which is programmed to implement a bang-bang control that regulates the temperature of the chamber. A desired temperature is inputted as a set point of the control system. Temperature of 45 °C is chosen as the operational drying temperature. Several tests have been carried out to examine the performance of the system including drying speed, the effects of ambient conditions, and the effects of mushroom size. The results show that the system can satisfy the objective.

Learning sustainability by developing a solar dryer for microalgae retrieval

Directory of Open Access Journals (Sweden)

Benedita Malheiro

2016-01-01

Full Text Available Excessive fossil fuel consumption is driving the search for alternative energy production solutions and, in particular, for sustainable sources of energy such as microalgae, from which biodiesel, among other useful compounds, can be obtained. After producing the microalgae, they must be harvested and dried. Existing drying solutions consume too much energy and are, therefore, expensive and unsustainable. The goal of this EPS@ISEP Spring 2013 project was to develop a solar microalgae dryer for the microalgae laboratory of ISEP. A multinational team of five students from distinct fields of study was responsible for designing and building the solar microalgae dryer prototype. The prototype includes a control system to ensure that the microalgae are not destroyed during the drying process. The solar microalgae dryer works as a distiller, extracting the excess water from the microalgae suspension. This paper details the design steps, the building technologies, the ethical and sustainable concerns and compares the prototype with existing solutions. The proposed sustainable microalgae drying process is competitive as far as energy usage is concerned. Finally, the project contributed to increase the team’s sustainable development awareness, active learning and motivation.

Field measurements of temperature profile for floatovoltaic dryer in the tropics

Science.gov (United States)

Osman, F. A.; Ya'acob, M. E.; Iskandar, A. Noor

2017-09-01

Most of the equator region in a tropical climate zone experiences hot and humid weather but sometimes heavy rain and thunderstorms which occur stochastically in monsoon season. Sunlight which is the energy source can be harvested approximately 8 hours (on average basis) daily throughout the year which leads to the promotion of Solar PV technologies. This works projects the field performance for a new Floatovoltaic Dryer prototype with flexible PV roofing structures covering the top of the dryer system. The field measurements are collected on the lake of Engineering Faculty, UPM supported with 4-parameter weather station. Temperature profile with RH measurements inside the Floatovoltaic Dryer compartments as compared to direct-sun drying mechanism are the main contributions of this work and it projects more than 12 W of convection heat energy could be harvested by using the clean system. The field measurements imply various points of thermocouple and humidity sensor throughout the experiment. Temperature and humidity will be the main elements recorded to analyze the differences under monocrystalline PV panel as compared to natural drying.

Nutritional potential of green banana flour obtained by drying in spouted bed

Directory of Open Access Journals (Sweden)

Carolina Vieira Bezerra

2013-12-01

Full Text Available This study evaluated the chemical composition of peeled and unpeeled green banana Cavendish (AAA flour obtained by drying in spouted bed, aiming at adding nutritional value to food products. The bananas were sliced and crushed to obtain a paste and fed to the spouted bed dryer (12 cm height and T = 80 ºC in order to obtain flour. The flours obtained were subjected to analysis of moisture, protein, ash, carbohydrates, total starch, resistant starch, fiber. The green banana flours, mainly unpeeled, are good sources of fiber and resistant starch with an average of 21.91g/100g and 68.02g/100g respectively. The protein content was found in an average of 4.76g/100g, being classified as a low biological value protein with lysine as the first limiting amino acid. The results showed that unpeeled green banana flour obtained by spouted bed drying can be a valuable tool to add nutritional value to products in order to increase their non-digestible fraction.

DEVELOPMENT OF VACUUM SUBLIMATION DRYERS USING THERMOELECTRIC MODULES

Directory of Open Access Journals (Sweden)

R. A. Barykin

2014-01-01

Full Text Available Summary. The main directions of use of freeze-dryed products and ingredients are revealed. The analysis of sales markets of freeze-dryed products is provided. It is shown that introduction of innovative production technologies will allow to develop dynamically not only to the large companies, but also small firms that will create prerequisites for growth of the Russian market of freeze-dryed products. Tendencies of development of the freeze-drying equipment are analysed. Relevance of development of energy saving freeze-dryers is proved The integrated approach to creation of competitive domestic technologies and the equipment for sublimation dehydration of thermolabile products consists in use of the effective combined remedies of a power supply, a process intensification, reduction of specific energy consumption and, as a result, decrease in product cost at achievement of high quality indicators. Advantages of thermoelectric modules as alternative direction to existing vapor-compression and absorbing refrigerating appliances are given. Researches of process of freeze-drying dehydration with use of thermoelectric modules are conducted. It is scientifically confirmed, that the thermoelectric module working at Peltier effect, promotes increase in refrigerating capacity due to use of the principle of the thermal pump. Options of use of thermoelectric modules in designs of dryers are offered. Optimum operating modes and number of modules in section are defined. Ways of increase of power efficiency of freeze-dryers with use of thermoelectric modules are specified. The received results will allow to make engineering calculations and design of progressive freeze-drying installations with various ways of a power supply.

Development and performance evaluation of a locally fabricated portable solar tunnel dryer for drying of fruits, vegetables and medicinal plants

International Nuclear Information System (INIS)

Munir, A.; Sultan, U.; Iqbal, M.

2013-01-01

The research was conducted to fabricate and develop a portable solar tunnel dryer (STD) for the drying of fruits, vegetables and medicinal plants. The system was designed as a portable system for decentralized applications at various sites to satisfy the drying requirements of small farmers and co-operatives. The cross sectional area of the solar tunnel dryer was trapezoidal in shape having 0.254 m/sup 2/ face area, with length and width of three meters and one meter respectively. It comprises a collector section (1.35 m) long and a drying section (1.65 m long) and two PV powered DC fans to provide the required air flow rate over the perishable agricultural products to be dried. Transparent polythene cover was used to close the dryer on top side to maintain the steady state air flow within the dryer. It has been observed that the drying air temperature was easily raised by some 8-14 degree C above the ambient temperature at air velocity ranges 0-1 m s/sup -1/. The efficiency of the solar tunnel dryer was found to be 40-45%. Psychrometric analysis was also carried out within the dryer and the process curves were drawn. The process curves were found similar to a conventional dryer showing that this dryer can be successfully utilized for the drying of agricultural products using solar energy. (author)

The effect of dryer load on freeze drying process design.

Science.gov (United States)

Patel, Sajal M; Jameel, Feroz; Pikal, Michael J

2010-10-01

Freeze-drying using a partial load is a common occurrence during the early manufacturing stages when insufficient amounts of active pharmaceutical ingredient (API) are available. In such cases, the immediate production needs are met by performing lyophilization with less than a full freeze dryer load. However, it is not obvious at what fractional load significant deviations from full load behavior begin. The objective of this research was to systematically study the effects of variation in product load on freeze drying behavior in laboratory, pilot and clinical scale freeze-dryers. Experiments were conducted with 5% mannitol (high heat and mass flux) and 5% sucrose (low heat and mass flux) at different product loads (100%, 50%, 10%, and 2%). Product temperature was measured in edge as well as center vials with thermocouples. Specific surface area (SSA) was measured by BET gas adsorption analysis and residual moisture was measured by Karl Fischer. In the lab scale freeze-dryer, the molar flux of inert gas was determined by direct flow measurement using a flowmeter and the molar flux of water vapor was determined by manometric temperature measurement (MTM) and tunable diode laser absorption spectroscopy (TDLAS) techniques. Comparative pressure measurement (capacitance manometer vs. Pirani) was used to determine primary drying time. For both 5% mannitol and 5% sucrose, primary drying time decreases and product temperature increases as the load on the shelves decreases. No systematic variation was observed in residual moisture and vapor composition as load decreased. Further, SSA data suggests that there are no significant freezing differences under different load conditions. Independent of dryer scale, among all the effects, variation in radiation heat transfer from the chamber walls to the product seems to be the dominant effect resulting in shorter primary drying time as the load on the shelf decreases (i.e., the fraction of edge vials increases).

Farm level evaluation of biomass energy operated seed dryer at selected sites of Bangladesh

International Nuclear Information System (INIS)

Rahman, S.M.M.; Bhuiyan, M.G.K.; Rahman, M.A.; Baqui, M.A.; Bala, B.K.

2006-01-01

Drying is one of the major problem in post harvest and processing of farm produce specially paddy seed in Bangladesh resulting tremendous shortage of quality seed. Evaluation through demonstrations was undertaken for the resource poor farmers at the selected sites to have practical experience of the IRRI-BRRI seed dryer. Viability of the dried paddy was more than 90% after six months of storage. The farmers were satisfied on the performance of the dryer. 68-100% farmers were motivated to hire the dyer during Boro and Aus seasons. Thus, the farm level evaluation and adoption of seed dryer will give a better alternative, aware and motivate the farmers on producing quality seed through proper drying and will contribute increased production

Feasibility analysis of heat pump dryer to dry hawthorn cake

International Nuclear Information System (INIS)

Wang, D.C.; Zhang, G.; Han, Y.P.; Zhang, J.P.; Tian, X.L.

2011-01-01

Highlights: → A heat pump dryer (HPD) is effectively proposed to dry hawthorn cake-likely materials. → Low drying temperature and high COP of heat pump are obtained in drying beginning. → HPD is more effective, economic than a traditional hot air dryer. → Feasibility of the HPD is also validated by the operation economy estimation. - Abstract: A heat pump dryer (HPD) would be an economic, environmentally friendly, hygienic drying machine used to dry some food, such as hawthorn cakes. Based on the production process of the hawthorn cake, a HPD is proposed and its basic principle is introduced. The experimental drying curves of the hawthorn cake using the heat pump drying method and the traditional hot air drying method are compared and analyzed. The drying process of hawthorn cakes is similar to that of the other drying materials. The higher drying temperature causes a faster drying process. But in the initial stage of the heat pump drying process, the water content of the hawthorn cake is not sensitive to the drying temperature, so a lower drying air temperature can be available in order to get a higher coefficient of performance (COP) of the heat pump (HP). The experimental results and the economic analysis indicate that the HPD is feasibly used to dry hawthorn cakes.

Feasibility analysis of heat pump dryer to dry hawthorn cake

Energy Technology Data Exchange (ETDEWEB)

Wang, D.C., E-mail: wdechang@163.com [College of Electromechanical Engineering, Qingdao University, Qingdao 266071 (China); Zhang, G.; Han, Y.P.; Zhang, J.P.; Tian, X.L. [College of Electromechanical Engineering, Qingdao University, Qingdao 266071 (China)

2011-08-15

Highlights: {yields} A heat pump dryer (HPD) is effectively proposed to dry hawthorn cake-likely materials. {yields} Low drying temperature and high COP of heat pump are obtained in drying beginning. {yields} HPD is more effective, economic than a traditional hot air dryer. {yields} Feasibility of the HPD is also validated by the operation economy estimation. - Abstract: A heat pump dryer (HPD) would be an economic, environmentally friendly, hygienic drying machine used to dry some food, such as hawthorn cakes. Based on the production process of the hawthorn cake, a HPD is proposed and its basic principle is introduced. The experimental drying curves of the hawthorn cake using the heat pump drying method and the traditional hot air drying method are compared and analyzed. The drying process of hawthorn cakes is similar to that of the other drying materials. The higher drying temperature causes a faster drying process. But in the initial stage of the heat pump drying process, the water content of the hawthorn cake is not sensitive to the drying temperature, so a lower drying air temperature can be available in order to get a higher coefficient of performance (COP) of the heat pump (HP). The experimental results and the economic analysis indicate that the HPD is feasibly used to dry hawthorn cakes.

Design, manufacture and modeling of a mixed mode dryer for pistachio in Kerman

Energy Technology Data Exchange (ETDEWEB)

Ameri, Mehran; Zangiabadi, Bijan; Mahmoudabadi, Mehdi [Department of Mechanical Engineering, Shahid Bahonar University, Kerman (Iran, Islamic Republic of)

2006-01-15

Production of high quality nuts that have toxics less than 2-2.5 ppm requires a great attention during growing and post harvest processing. Gravitational or Wagon driver using fossil fuel has been traditionally performed to dry pistachio nuts. However, using of fossil fuel is subject to the noxious effects on nuts such as burning, discoloured and various toxic fumes as well as the biological pollution. In Kerman province in south of Iran, where 60% of pistachio nuts export to all over the world, due to long period of sunshine during harvesting season, solar drying are know to be an excellence alternative to the fossil fuel. A specimen mixed-mode solar-dryer is manufactured to study the feasibility of test and to investigate optimization of the drying process in several conditions. Furthermore this designed dryer for pistachio nuts can be simply used for drying of the various agriculture products like fruits and vegetables. With this proposed multi application solar dryer, one can easily reach to acceptable moisture (7%) in a short period of time. For this system a mathematical model of dryer is also suggested here. the proposed solar dryer includes three main parts as collector, chamber and photocell. Chamber has a glassy cover that permits nut expose beam radiation directly. Collector has ability to circulate air by buoyancy forces or convey air by suction fans due to different operation conditions. Photocells prepare electromotive force for fans.National capacity of the dryer is 50Kg. The maximum temperature inside collector at the end of harvest season is 60 degree centigrade during 8-16 local time. In the mathematical modeling after fitting the drawing curves with the remaining moisture amount in the nuts and temperature per drying time, it was found that the major drop in the moisture content of the nuts occurs during the first 9 hours and then decreases gradually. The final moisture amount of the nuts was about 6% in 42 hours. The accuracy of proposed method

Design, manufacture and modeling of a mixed mode dryer for pistachio in Kerman

International Nuclear Information System (INIS)

Ameri, Mehran; Zangiabadi, Bijan; Mahmoudabadi, Mehdi

2006-01-01

Production of high quality nuts that have toxics less than 2-2.5 ppm requires a great attention during growing and post harvest processing. Gravitational or Wagon driver using fossil fuel has been traditionally performed to dry pistachio nuts. However, using of fossil fuel is subject to the noxious effects on nuts such as burning, discoloured and various toxic fumes as well as the biological pollution. In Kerman province in south of Iran, where 60% of pistachio nuts export to all over the world, due to long period of sunshine during harvesting season, solar drying are know to be an excellence alternative to the fossil fuel. A specimen mixed-mode solar-dryer is manufactured to study the feasibility of test and to investigate optimization of the drying process in several conditions. Furthermore this designed dryer for pistachio nuts can be simply used for drying of the various agriculture products like fruits and vegetables. With this proposed multi application solar dryer, one can easily reach to acceptable moisture (7%) in a short period of time. For this system a mathematical model of dryer is also suggested here. the proposed solar dryer includes three main parts as collector, chamber and photocell. Chamber has a glassy cover that permits nut expose beam radiation directly. Collector has ability to circulate air by buoyancy forces or convey air by suction fans due to different operation conditions. Photocells prepare electromotive force for fans.National capacity of the dryer is 50Kg. The maximum temperature inside collector at the end of harvest season is 60 degree centigrade during 8-16 local time. In the mathematical modeling after fitting the drawing curves with the remaining moisture amount in the nuts and temperature per drying time, it was found that the major drop in the moisture content of the nuts occurs during the first 9 hours and then decreases gradually. The final moisture amount of the nuts was about 6% in 42 hours. The accuracy of proposed method

A study of the drying effect on lemon slices using a closed-type solar dryer

Energy Technology Data Exchange (ETDEWEB)

Ho-Hsien Chen; Hernandez, C.E.; Tzou-Chi Huang [National Pingtung University of Science and Technology (China). Dept. of Food Science

2005-01-01

An experimental closed-type dryer associated with a photovoltaic system (PV) was developed. The transparent drying cabinet was designed with high transmittance glass to decrease the reflection of direct sunlight and to offer extra direct solar heating on the raw material during drying. Parallel wiring with a local electrical grid was necessary for switching purposes if there is insufficient battery backup during peak operation. Lemon slices were dried using the closed-type solar dryer and results were compared with hot air drying at 60{sup o}C. The results indicate that the dried lemon slices using a closed-type solar dryer has better general levels of quality in terms of sensory parameters. (author)

Design and Fabrication of a Direct Natural Convection Solar Dryer for Tapioca

Directory of Open Access Journals (Sweden)

Diemuodeke E. OGHENERUONA

2011-06-01

Full Text Available Based on preliminary investigations under controlled conditions of drying experiments, a direct natural convection solar dryer was designed and fabricated to dry tapioca in the rural area. This paper describes the design considerations followed and presents the results of MS excel computed results of the design parameters. A minimum of 7.56 m2 solar collector area is required to dry a batch of 100 kg tapioca in 20 hours (two days drying period. The initial and final moisture content considered were 79 % and 10 % wet basis, respectively. The average ambient conditions are 32ºC air temperatures and 74 % relative humidity with daily global solar radiation incident on horizontal surface of 13 MJ/m2/day. The weather conditions considered are of Warri (lat. 5°30’, long. 5°41’, Nigeria. A prototype of the dryer so designed was fabricated with minimum collector area of 1.08 m2. This prototype dryer will be used in experimental drying tests under various loading conditions.

Technical and environmental analysis of biofuel dryers; Teknisk och miljoemaessig analys av biobraensletorkar

Energy Technology Data Exchange (ETDEWEB)

Muenter, M; Hagman, U; Harnevie, H; Johansen, H; Kristensson, I; Westermark, M; Viberg, T [Vattenfall Energimarknad, Stockholm (Sweden)

1999-03-01

A study regarding technology and environmental impact of the drying process of biofuels has been conducted. In the study two different types of dryers are analyzed. The result from the study shows that emissions of primarily hydrocarbons is high from the direct technic. The emission can be decreased considerably by improving the burner of the dryer. For the indirect technic the evaporated water give rise to problems in the sewage treatment plant. Studies show that biological treatment will result in an acceptable condensate.

Mushroom dehydration in a hybrid-solar dryer

International Nuclear Information System (INIS)

Reyes, Alejandro; Mahn, Andrea; Cubillos, Francisco; Huenulaf, Pedro

2013-01-01

Highlights: ► Mushrooms (Paris variety) were dehydrated in a hybrid solar dryer. ► Effective diffusivity was estimated by the Constant Diffusivity Model. ► Drying kinetics were adjusted by a semi-theoretical and the empirical Page model. ► Temperature, thickness and air recycle significantly affected critical moisture. ► The input of solar energy resulted in 3.5–12.5% electrical energy saving. - Abstract: Mushrooms (Paris variety) were dehydrated in a hybrid solar dryer (HSD) provided with a 3 m 2 solar panel and electric resistances. Mushrooms were cut in 8 mm or 4 mm thickness slices. At the outlet of the tray dryer 80–90% air was recycled and the air temperature was adjusted to the pre-defined levels (50 or 60 °C). At the outlet of the solar panel the air temperature raised between 2 and 20 °C above the ambient temperature, depending mainly of solar radiation level. Temperature, slices thickness and air recycle level had statistically significant effects on critical moisture content (X c ), as well as on the time necessary to reach a moisture content of 0.1 (wb). The color parameters of dehydrated mushroom indicate a notorious darkening, in all runs. Rehydration assays at 35 °C showed that in less than 30 min rehydrated mushrooms reached a moisture content of 0.8 (wb). Effective diffusivity (D eff ) was estimated by the Simplified Constant Diffusivity Model (SCDM), and it ranged between 6E−10 and 40E−10 m 2 /s, with R 2 higher than 0.98, agreeing with literature. The adjustment of experimental drying kinetics with the empirical Page’s model resulted in R 2 higher than 0.997. Finally, the input of solar energy resulted in 3.5–12.5% energy saving. These values could even be improved by increasing the agro-product load in the HSD

Application of artificial neural network method to exergy and energy analyses of fluidized bed dryer for potato cubes

International Nuclear Information System (INIS)

Azadbakht, Mohsen; Aghili, Hajar; Ziaratban, Armin; Torshizi, Mohammad Vahedi

2017-01-01

Drying the samples was performed in the inlet temperatures of 45, 50, and 55 °C, air velocity of 3.2, 6.8, and 9.1 m s"−"1, and bed depth of 1.5, 2.2, and 3 cm. The effects of these parameters were evaluated on energy utilization, energy efficiency and utilization ratio and exergy loss and efficiency. Furthermore, artificial neural network was employed in order to predict the energy and exergy parameters, and simulation of thermodynamic drying process was carried out, using the ANN created. A network was constructed from learning algorithms and transfer functions that could predict, with good accuracy, the exergy and energy parameters related to the drying process. The results revealed that energy utilization, efficiency, and utilization ratio increased by increasing the air velocity and depth of the bed; however, energy utilization and efficiency were augmented by increasing the temperature; additionally, energy utilization ratio decreased along with the rise in temperature. Also was found that exergy loss and efficiency improved by increasing the air velocity, temperature, and depth of the bed. Finally, the results of the statistical analyses indicated that neural networks can be utilized in intelligent drying process which has a large share of energy utilization in the food industry. - Highlights: • Energy utilization increased by increasing temperature, air velocity and depth of the bed. • Exergy loss increased with increasing the air velocity, temperature and depth of the bed. • Prediction by a trained neural network is faster than usual mathematical models. • ANN it is a suitable method to predict the energy and exergy in various driers.

Improving Dryer and Press Efficiencies Through Combustion of Hydrocarbon Emissions

Energy Technology Data Exchange (ETDEWEB)

Sujit Banerjee

2005-10-31

Emission control devices on dryers and presses have been legislated into the industry, and are now an integral part of the drying system. These devices consume large quantities of natural gas and electricity and down-sizing or eliminating them will provide major energy savings. The principal strategy taken here focuses on developing process changes that should minimize (and in some cases eliminate) the need for controls. A second approach is to develop lower-cost control options. It has been shown in laboratory and full-scale work that Hazardous Air Pollutants (HAPs) emerge mainly at the end of the press cycle for particleboard, and, by extension, to other prod-ucts. Hence, only the air associated with this point of the cycle need be captured and treated. A model for estimating terpene emissions in the various zones of veneer dryers has been developed. This should allow the emissions to be concentrated in some zones and minimized in others, so that some of the air could be directly released without controls. Low-cost catalysts have been developed for controlling HAPs from dryers and presses. Catalysts conventionally used for regenerative catalytic oxidizers can be used at much lower temperatures for treating press emissions. Fluidized wood ash is an especially inexpensive mate-rial for efficiently reducing formaldehyde in dryer emissions. A heat transfer model for estimating pinene emissions from hot-pressing strand for the manufacture of flakeboard has been constructed from first principles and validated. The model shows that most of the emissions originate from the 1-mm layer of wood adjoining the platen surface. Hence, a simple control option is to surface a softwood mat with a layer of hardwood prior to pressing. Fines release a disproportionate large quantity of HAPs, and it has been shown both theo-retically and in full-scale work that particles smaller than 400 µm are principally responsible. Georgia-Pacific is considering green

Design, construction and test run of a two-tonne capacity solar rice dryer with rice-husk-fired auxiliary heater

International Nuclear Information System (INIS)

Iloeje, O.C.; Ekechukwu, O.V.; Ezeike, G.O.I.

1993-09-01

The design and construction details of a two-tonne per batch capacity natural-circulation solar rice dryer and the highlights of the design of its rice-husk-fired auxiliary heating system which is still under construction are presented. The dryer measures approximately 17.7m long by 9.8m wide by 6m high. Preliminary results of a test run on the solar dryer section only is reported. (author). 5 refs, 3 figs

Development of a multi-purpose dryer | Kadurumba | Nigeria ...

African Journals Online (AJOL)

The novel design uses heat sources from electric burners and it is located beneath the product spreading chamber. This prevented the problem of discoloration due to direct heat from the burners. A thermostat was used for its temperature control and light indicators were introduced to monitor the operation of the dryer with a ...

Removal of VOCs by hybrid electron beam reactor with catalyst bed

International Nuclear Information System (INIS)

Kim, Jinkyu; Han, Bumsoo; Kim, Yuri; Lee, J.H.; Park, C.R.; Kim, J.C.; Kim, J.C.; Kim, K.J.

2004-01-01

Electron beam decomposition of volatile organic compounds (VOCs) was studied in order to obtain information for developing effective treatment method of off-gases from industries. We have examined the combination of electron beam and catalyst honeycomb which is either 1% platinum based or ceramic honeycomb- based aluminum oxide, using a hybrid reactor in order to improve removal efficiency and CO 2 formation; and to suppress undesirable by-product formation e.g. O 3 , aerosol, H x C y. , and tar. The experiments were conducted using a pilot-scale treatment system (maximum capacity; 1800 N m 3 /h) that fitted the field size to scale up from the traditional laboratory scale system for VOC removal with electron beam irradiation. Toluene was selected as a typical VOC that was irradiated to investigate product formation, effect of ceramic and catalyst, and factors effecting overall efficiency of degradation. Styrene was selected as the most odorous compound among the VOCs of interest. It was found that VOCs could be destroyed more effectively using a hybrid system with catalyst bed than with electron beam irradiation only

A large-scale solar greenhouse dryer using polycarbonate cover: Modeling and testing in a tropical environment of Lao People's Democratic Republic

Energy Technology Data Exchange (ETDEWEB)

Janjai, Serm; Intawee, Poolsak; Kaewkiew, Jinda; Sritus, Chanoke [Solar Energy Research Laboratory, Department of Physics, Faculty of Science, Silpakorn University, Nakhon Pathom 73000 (Thailand); Khamvongsa, Vathsana [Department of Physics, Faculty of Natural Science, National University of Laos, P O Box 7322, Vientiane (Lao People' s Democratic Republic)

2011-03-15

A large-scale solar greenhouse dryer with a loading capacity of 1000 kg of fruits or vegetables has been developed and tested at field levels. The dryer has a parabolic shape and the dryer is covered with polycarbonate sheets. The base of the dryer is a black concrete floor with an area of 7.5 x 20.0 m{sup 2}. Nine DC fans powered by three 50-W solar cell modules are used to ventilate the dryer. The dryer was installed at Champasak (15.13 N, 105.79 E) in Lao People's Democratic Republic (Lao PDR). It is routinely used to dry chilli, banana and coffee. To assess the experimental performances of the dryer, air temperature, air relative humidity and product moisture contents were measured. One thousand kilograms of banana with the initial moisture content of 68% (wb) was dried within 5 days, compared to 7 days required for natural sun drying with the same weather conditions. Also three hundred kilograms of chilli with the initial moisture content of 75% (wb) was dried within 3 days while the natural sun drying needed 5 days. Two hundred kilograms of coffee with the initial moisture content of 52% (wb) was dried within 2 days as compared to 4 days required for natural sun drying. The chilli, coffee and banana dried in this dryer were completely protected from insects, animals and rain. Furthermore, good quality of dried products was obtained. The payback period of the dryer is estimated to be 2.5 years. A system of partial differential equations describing heat and moisture transfer during drying of chilli, coffee and banana in the greenhouse dryer was developed. These equations were solved by using the finite different method. The simulated results agree well with the experimental data. This model can be used to provide the design data for this type of dryer in other locations. (author)

Thermal decomposition study of uranyl nitrate and cerium hydroxide in a spray dryer

International Nuclear Information System (INIS)

Silva Wildhagen, G.R. da.

1993-05-01

A study, in a spray dryer system based on drying and thermal decomposition of uranyl nitrate solutions aiming the production of uranium trioxide adequate for the use in posterior steps of reduction and hydro fluorination in nuclear fuel cycle; and cerium hydroxide suspensions for the production of cerium oxide with high surface area is presented. Thus, the project and construction of a countercurrent spray dryer was elaborated for capacity of 10 Kg U O 3 /h and 3,5 k Ce O 2 /h. The methodology used in these experiments consisted in the analysis of several parameters (concentration and flow rate of the feed, atomization pressure and inlet temperature of the dryer) over the physical and chemical properties of the products. Using the obtained results, with the help of a mathematical model, it was developed the project of a continuous pilot unity for the production of uranium trioxide or cerium oxide, with capacity of 20 Kg U O 3 /h or 10 Kg Ce O 2 /h, respectively. (author)

A solar assisted heat-pump dryer and water heater

International Nuclear Information System (INIS)

Hawlader, M.N.A.; Chou, S.K.; Jahangeer, K.A.; Rahman, S.M.A.

2006-01-01

Growing concern about the depletion of conventional energy resources has provided impetus for considerable research and development in the area of alternative energy sources. A solar assisted heat pump dryer and water heater found to be one of the solutions while exploring for alternative energy sources. The heat pump system is used for drying and water heating applications with the major share of the energy derived from the sun and the ambient. The solar assisted heat pump dryer and water heater has been designed, fabricated and tested. The performance of the system has been investigated under the meteorological conditions of Singapore. The system consists of a variable speed reciprocating compressor, evaporator-collector, storage tank, air cooled condenser, auxiliary heater, blower, dryer, dehumidifier, and air collector. The drying medium used is air and the drying chamber is configured to carry out batch drying of good grains. A water tank connected in series with the air cooled condenser delivers hot water for domestic applications. The water tank also ensures complete condensation of the refrigerant vapour. A simulation program is developed using Fortran language to evaluate the performance of the system and the influence of different variables. The performance indices considered to evaluate the performance of the system are: Solar Fraction (SF), Coefficient of Performance (COP) and Specific Moisture Extraction Rate (SMER). A COP value of 7.5 for a compressor speed of 1800 rpm was observed. Maximum collector efficiencies of 0.86 and 0.81 have been found for evaporator-collector and air collector, respectively. A value of the SMER of 0.79 has been obtained for a load of 20 kg and a compressor speed of 1200 rpm

Modulating protein release profiles by incorporating hyaluronic acid into PLGA microparticles Via a spray dryer equipped with a 3-fluid nozzle

DEFF Research Database (Denmark)

Wan, Feng; Maltesen, Morten Jonas; Andersen, Sune Klint

2014-01-01

with or without HA were prepared using a spray dryer equipped with a 3-fluid nozzle. The effects of HA on the surface tension and the rheological behavior of the inner feed solution were investigated. The physicochemical properties of the resulting microparticles were characterized using scanning electron......: The present work demonstrates the potential of HA to modulate protein release profile from PLGA microparticle formulations produced via spray drying using 3-fluid nozzle....

Development of Simple Drying Model for Performance Prediction of Solar Dryer: Theoretical Analysis

DEFF Research Database (Denmark)

Singh, Shobhana; Kumar, Subodh

2012-01-01

An analytical moisture diffusion model which considers the influence of external resistance to mass transfer is developed to predict thermal performance of dryer system. The moisture diffusion coefficient, Deff that is necessary to evaluate the prediction model has been determined in terms...... of experimental drying parameters. A laboratory model of mixed-mode solar dryer system is tested with cylindrical potato samples of thickness 5 and 18 mm under simulated indoor conditions. The potato samples were dried at a constant absorbed thermal energy of 750 W/m2 and air mass flow rate of 0.011 kg...

Transformation of carbon tetrachloride in an anaerobic packed-bed reactor without addition of another electron donor

NARCIS (Netherlands)

de Best, JH; Hunneman, P; Doddema, HJ; Janssen, DB; Harder, W; Doddema, Hans J.

1999-01-01

Carbon tetrachloride (52 mu M) was biodegraded for more than 72% in an anaerobic packed-bed reactor without addition of an external electron donor. The chloride mass balance demonstrated that all carbon tetrachloride transformed was completely dechlorinated. Chloroform and dichloromethane were

Transformation of carbon tetrachloride in an anaerobic packed-bed reactor without addition of another electron donor

NARCIS (Netherlands)

Best, J.H. de; Hunneman, P.; Doddema, H.J.; Janssen, D.B.; Harder, W.

1999-01-01

Carbon tetrachloride (52 μM) was biodegraded for more than 72% in an anaerobic packed-bed reactor without addition of an external electron donor. The chloride mass balance demonstrated that all carbon tetrachloride transformed was completely dechlorinated. Chloroform and dichloromethane were

Performance analysis of greenhouse dryer by using insulated north-wall under natural convection mode

Directory of Open Access Journals (Sweden)

Prashant Singh Chauhan

2016-11-01

Full Text Available A prototype north wall insulated greenhouse dryer has been fabricated and tested in no-load conditions under natural convection mode. Experimentation has been conducted in two different cases. Case-I is when solar collector placed inside the dryer and Case-II is North wall insulated greenhouse dryer without solar collector. Coefficient of performance, heat utilisation factor, convective heat transfer coefficient and coefficient of diffusivity have been evaluated in thermal performance analysis. The difference of the highest convective heat transfer coefficient of both cases is 29.094W/m2°C which is showing the effectiveness of insulated north wall and solar collector. The maximum coefficient of diffusivity (0.0827 was achieved during the third day of experiment in Case-II. The inside room temperature of wall insulated greenhouse dryer for Case-I is 4.11%, 5.08 % and 11.61 % higher than the Case-II during the day 1, day 2 and day 3 respectively. This result is also showing the effectiveness of solar collector and insulated north wall. The highest heat utilisation factor (0.616 is obtained during the second day for Case-I while for Case-II it is 0.769 during the third day of experimentation. Maximum coefficient of performance achieved is 0.892 during the third day of the experiment for Case-I whereas 0.953 is obtained on the first day of experimentation for Case-II.

Drying of Rosella (Hibiscus sabdariffa) Flower Petals using Solar Dryer with Double Glass Cover Collector

OpenAIRE

Tjukup Marnoto

2014-01-01

Chemical ingredients in rosella petals are very beneficial for health. Rosella petals needed to be drained for storage and packing purpose. The traditional drying takes 5 days and less healthy. Solar dryer technology can speed up the drying process and protect materials from dust contamination. Solar dryer with double glass covered collector has been designed and made for drying of agricultural products such as rosella flowers. Rosella petals as much as 2300 grams with initial moisture conten...

Steam generator with integral downdraft dryer. Final project report

Energy Technology Data Exchange (ETDEWEB)

Hochmuth, F.W.

1992-02-01

On June 30, 1989, a financial assistance award was granted by the United State Department of Energy, the purpose of which was to study and evaluate the technical aspect, the economic viability, and commercial possibilities of a new furnace design for burning high moisture cellulose type fuels. The new design is an invention by F.W. Hochmuth, P.Eng. and has received United States Patents Nos. 4,480, 557 and 4,502,397. It was conceived as a method to improve the general operation and efficiency of waste wood burning boilers, to avoid the use of stabilizing fuels such as oil or gas, and to reduce objectionable stack emissions. A further objective was to obtain such benefits at relatively low cost by integrating all new material requirements within the furnace itself thereby avoiding the need for costly external equipment. The proposed integral down-draft dryer avoids the use of external dryer systems that are very expensive, have high power consumption, and require a large amount of maintenance. This document provides the details of this invention.

Performance of a convective, infrared and combined infrared- convective heated conveyor-belt dryer.

Science.gov (United States)

El-Mesery, Hany S; Mwithiga, Gikuru

2015-05-01

A conveyor-belt dryer was developed using a combined infrared and hot air heating system that can be used in the drying of fruits and vegetables. The drying system having two chambers was fitted with infrared radiation heaters and through-flow hot air was provided from a convective heating system. The system was designed to operate under either infrared radiation and cold air (IR-CA) settings of 2000 W/m(2) with forced ambient air at 30 °C and air flow of 0.6 m/s or combined infrared and hot air convection (IR-HA) dryer setting with infrared intensity set at 2000 W/m(2) and hot at 60 °C being blown through the dryer at a velocity of 0.6 m/s or hot air convection (HA) at an air temperature of 60 °C and air flow velocity 0.6 m/s but without infrared heating. Apple slices dried under the different dryer settings were evaluated for quality and energy requirements. It was found that drying of apple (Golden Delicious) slices took place in the falling rate drying period and no constant rate period of drying was observed under any of the test conditions. The IR-HA setting was 57.5 and 39.1 % faster than IR-CA and HA setting, respectively. Specific energy consumption was lower and thermal efficiency was higher for the IR-HA setting when compared to both IR-CA and HA settings. The rehydration ratio, shrinkage and colour properties of apples dried under IR-HA conditions were better than for either IR-CA or HA.

Comparison of three control strategies for optimization of spray dryer operation

DEFF Research Database (Denmark)

Petersen, Lars Norbert; Poulsen, Niels Kjølstad; Niemann, Hans Henrik

2017-01-01

controllers for operation of a four-stage spray dryer. The three controllers are a proportional-integral (PI) controller that is used in industrial practice for spray dryer operation, a linear model predictive controller with real-time optimization (MPC with RTO, MPC-RTO), and an economically optimizing...... nonlinear model predictive controller (E-NMPC). The MPC with RTO is based on the same linear state space model in the MPC and the RTO layer. The E-NMPC consists of a single optimization layer that uses a nonlinear system of ordinary differential equations for its predictions. The PI control strategy has...... the production rate, while minimizing the energy consumption, keeping the residual moisture content of the powder below a maximum limit, and avoiding that the powder sticks to the chamber walls. We use an industrially recorded disturbance scenario in order to produce realistic simulations and conclusions...

Laboratory Development of A High Capacity Gas-Fired paper Dryer

Energy Technology Data Exchange (ETDEWEB)

Chudnovsky, Yaroslav [Gas Technology Institute, Des Plaines, IL (United States); Kozlov, Aleksandr [Gas Technology Institute, Des Plaines, IL (United States); Sherrow, Lester [Gas Technology Institute, Des Plaines, IL (United States)

2005-09-30

Paper drying is the most energy-intensive and temperature-critical aspect of papermaking. It is estimated that about 67% of the total energy required in papermaking is used to dry paper. The conventional drying method uses a series of steam-heated metal cylinders that are required to meet ASME codes for pressure vessels, which limits the steam pressure to about 160 psig. Consequently, the shell temperature and the drying capacity are also limited. Gas Technology Institute together with Boise Paper Solutions, Groupe Laparrier and Verreault (GL&V) USA Inc., Flynn Burner Corporation and with funding support from the U.S. Department of Energy, U.S. natural gas industry, and Gas Research Institute is developing a high efficiency gas-fired paper dryer based on a combination of a ribbon burner and advanced heat transfer enhancement technique. The Gas-Fired Paper Dryer (GFPD) is a high-efficiency alternative to conventional steam-heated drying drums that typically operate at surface temperatures in the 300ºF range. The new approach was evaluated in laboratory and pilot-scale testing at the Western Michigan University Paper Pilot Plant. Drum surface temperatures of more than 400ºF were reached with linerboard (basis weight 126 lb/3000 ft2) production and resulted in a 4-5 times increase in drying rate over a conventional steam-heated drying drum. Successful GFPD development and commercialization will provide large energy savings to the paper industry and increase paper production rates from dryer-limited (space- or steam-limited) paper machines by an estimated 10 to 20%, resulting in significant capital costs savings for both retrofits and new capacity.

Drying of Ceramic Hollow Bricks in an Industrial Tunnel Dryer: A Finite Volume Analysis

Directory of Open Access Journals (Sweden)

F Tavares

2016-10-01

Full Text Available This paper aims to study the drying of industrial hollow bricks in a tunnel dryer cross flow type. The theoretical model is based on mass and energy conservation equations applied to air and product. To validate the methodology, numerical and experimental results for the moisture content and the temperature of brick during the drying in an industrial scale are compared and a good correlation was obtained. Results of moisture content and temperature of the product, and temperature, relative humidity and absolute humidity of drying air as a function of drying time and position in the dryer are presented and analyzed.

Improving adsorption dryer energy efficiency by simultaneous optimization and heat integration

NARCIS (Netherlands)

Atuonwu, J.C.; Straten, G. van; Deventer, H.C. van; Boxtel, A.J.B. van

2011-01-01

Conventionally, energy-saving techniques in drying technology are sequential in nature. First, the dryer is optimized without heat recovery and then, based on the obtained process conditions, heat recovery possibilities are explored. This work presents a methodology for energy-efficient adsorption

Design and Testing of a Natural Convection Solar Tunnel Dryer for Mango

Directory of Open Access Journals (Sweden)

Isaac Nyambe Simate

2017-01-01

Full Text Available A natural convection solar tunnel dryer comprising three major units, a solar collector unit, a drying unit, and a vertical bare flat-plate chimney, was constructed. No-load tests with a horizontal configuration of air entry into the collector resulted in a bidirectional air flow in the dryer. To correct this undesirable situation, an air guide at the collector was incorporated to ensure that air entered in a vertical direction. To investigate its performance, drying experiments with mango were carried out at the University of Zambia, Department of Agricultural Engineering. Uncertainties in the parameters measured in the experiment were analysed and quantified. The results showed that, under solar radiation between 568.4 and 999.5 W/m2, air temperature of up to 65.8°C was attained at the collector unit. The average relative humidity values were 30.8%, 6.4%, and 8.4% for the ambient, collector, and drying unit, respectively. Under these conditions, mango with an initial moisture content of 85.5% (wet basis was dried to 13.0% (wet basis in 9.5 hours. The collector, drying, and pick-up efficiencies were found to be 24.7%, 12.8%, and 35.0%, respectively. The average temperature difference between the chimney air and ambient air was 12.1°C, and this was sufficient in driving the flow of air through the dryer.

Novel temperature control technique for a medicinal herb dryer system powered by a photovoltaic array

International Nuclear Information System (INIS)

Abd El-Shafy A Nafeh; Hanaa M Fargali; Faten H Fahmy; Mohamed A Hassan

2006-01-01

Each plant has its own optimal drying temperature, especially for the medicinal herbs, because they are sensitive to heat. If the drying temperature becomes more than the optimal value, some chemical reactions will occur and influence the quality of the dried herb, such as color, taste, and aroma. While if the drying temperature becomes lower than the optimal value, the drying process will slow down; and consequently an expected degradation in the quality of the herb may occur, due to insects and fungi infestation which increase in moist conditions. This paper presents a new temperature control technique for a medicinal herb dryer system. The technique fixes the drying temperature of the medicinal herbs at 40 degree C, even in cases of rapidly changing atmospheric conditions. The control of the dryer temperature is achieved through using the proportional integral (PI) controller. The designed dryer contains two systems, which are the thermal and the electrical systems. The thermal system is designed to heat the drying air by using the solar energy and bio-gas fuel. Whereas, the electrical system, which contains a photovoltaic (PV) modules and a battery, is designed to supply the different electrical loads of the dryer system. The control technique is investigated through simulation work by using MATLAB-SIMULINK. The simulation results indicate the high capability of the proposed technique in controlling the drying temperature, even in cases of rapidly changing atmospheric conditions

Determination of stresses caused by fluctuation of acoustic load in the steam dryers of a BWR

International Nuclear Information System (INIS)

Centeno P, J.; Quezada G, S.; Prieto G, A.; Vazquez R, A.; Espinosa P, G.; Nunez C, A.

2014-10-01

The extended power up-rate (EPU) in a nuclear power plant cause various problems in BWR components also in the steam system. This due to increased steam flow generated in the reactor and is conveyed to the turbine by the four main steam lines (MSL). One of the most serious problems is the generation of acoustic pressure loads in the metal structure of the steam dryer which eventually leads to fatigue failure and even the appearance of cracks, and in turn it causes loose parts that are entrained by the steam and transported in the MSL. This problem is due to the fluctuation of load acoustics caused by the union of the safety or relief valves (SRV) with the MSL, spreading through these to reach the reactor pressure vessel (RPV) where the effect of resonance of the acoustic wave is amplified and impacts directly in the supporting structure of the steam dryer, skirt and the panels where the mixture liquid-steam is dried, by centrifugation effect and runoff of liquid water. Efforts in the steam dryer operating conditions of EPU for two cases will be analyzed in this work, the first is before the installation of Acoustic Side Branch (ASB), and in the second case we consider the installation of said ASB in the standpipes of SRV. The analysis was performed with numerical experiments on a platform for computational fluid dynamics with virtual geometries previously designed based on the actual components of the reactor and steam system. The model to study is delimited by the top of the RPV, the steam dryer and a section of each of the four MSL with ten standpipes of SRV. With the obtained data and considering the mechanical-structural properties of the steam dryer material, we can evaluate the mechanical resistance to impacts by acoustic pressure load and its possible deformation or cracking. (Author)

Modeling of thermal mode of drying special purposes ceramic products in batch action chamber dryers

Science.gov (United States)

Lukianov, E. S.; Lozovaya, S. Yu; Lozovoy, N. M.

2018-03-01

The article is devoted to the modeling of batch action chamber dryers in the processing line for producing shaped ceramic products. At the drying stage, for various reasons, most of these products are warped and cracked due to the occurrence of irregular shrinkage deformations due to the action of capillary forces. The primary cause is an untruly organized drying mode due to imperfection of chamber dryers design specifically because of the heat-transfer agent supply method and the possibility of creating a uniform temperature field in the whole volume of the chamber.

Multivariate statistical process control of a continuous pharmaceutical twin-screw granulation and fluid bed drying process.

Science.gov (United States)

Silva, A F; Sarraguça, M C; Fonteyne, M; Vercruysse, J; De Leersnyder, F; Vanhoorne, V; Bostijn, N; Verstraeten, M; Vervaet, C; Remon, J P; De Beer, T; Lopes, J A

2017-08-07

A multivariate statistical process control (MSPC) strategy was developed for the monitoring of the ConsiGma™-25 continuous tablet manufacturing line. Thirty-five logged variables encompassing three major units, being a twin screw high shear granulator, a fluid bed dryer and a product control unit, were used to monitor the process. The MSPC strategy was based on principal component analysis of data acquired under normal operating conditions using a series of four process runs. Runs with imposed disturbances in the dryer air flow and temperature, in the granulator barrel temperature, speed and liquid mass flow and in the powder dosing unit mass flow were utilized to evaluate the model's monitoring performance. The impact of the imposed deviations to the process continuity was also evaluated using Hotelling's T 2 and Q residuals statistics control charts. The influence of the individual process variables was assessed by analyzing contribution plots at specific time points. Results show that the imposed disturbances were all detected in both control charts. Overall, the MSPC strategy was successfully developed and applied. Additionally, deviations not associated with the imposed changes were detected, mainly in the granulator barrel temperature control. Copyright © 2017 Elsevier B.V. All rights reserved.

Economic Optimization of Spray Dryer Operation using Nonlinear Model Predictive Control

DEFF Research Database (Denmark)

Petersen, Lars Norbert; Poulsen, Niels Kjølstad; Niemann, Hans Henrik

2014-01-01

In this paper we investigate an economically optimizing Nonlinear Model Predictive Control (E-NMPC) for a spray drying process. By simulation we evaluate the economic potential of this E-NMPC compared to a conventional PID based control strategy. Spray drying is the preferred process to reduce...... the water content for many liquid foodstuffs and produces a free flowing powder. The main challenge in controlling the spray drying process is to meet the residual moisture specifications and avoid that the powder sticks to the chamber walls of the spray dryer. We present a model for a spray dryer that has...... been validated on experimental data from a pilot plant. We use this model for simulation as well as for prediction in the E-NMPC. The E-NMPC is designed with hard input constraints and soft output constraints. The open-loop optimal control problem in the E-NMPC is solved using the single...

Electron microscopy and phase analysis of fly ash from pressurized fluidized bed combustion

International Nuclear Information System (INIS)

Maenami, Hiroki; Isu, Norifumi; Ishida, Emile H.; Mitsuda, Takeshi

2004-01-01

The characterization of the typical fly ashes from pressurized fluidized bed combustion system (PFBC) in Japan and Europe was carried out by electron microscopy and phase analysis using energy-dispersive X-ray spectroscopy (EDX). The purity of limestone as in-bed sulfur removal sorbent influences the desulfurization reaction. The high-purity limestone yielded both hydroxyl ellestadite and anhydrite in Japanese PFBC ashes, while dolomite-rich limestone yielded anhydrite in European PFBC ashes. When the high-purity limestone was used, hydroxyl ellestadite particles were observed as the independent particles or the rim around limestone particles. The Al 2 O 3 content in the glassy phase was inversely proportional to the CaO content in the glassy phase, suggesting that the glassy phases were formed from metakaoline and calcite as end members. Since hydroxyl ellestadite, glassy phase and metakaoline are reactive under hydrothermal conditions, PFBC ashes are expected to be used as raw materials for autoclaved products

Performance Evaluation of an Active Solar Dryer Equipped with an Auxilliary Electrical Heater and Heat Recovery System

International Nuclear Information System (INIS)

Pourghasemi Ranjbar, M.; Alavi Naeini, N.; Mortezapour, H.

2016-01-01

Drying is a very sophisticated process which consumes a large amount of energy. Solar energy can be used as an alternative or supplementary energy source to fossil fuels. Solar dryers are common ways for saving fossil fuel consumption during agricultural products drying. In this study, the performance of an active solar dryer equipped with an energy recovery system was investigated at three levels of drying air temperature. The results showed that the energy recovery system was able to increase inlet air temperature by 16.8, 18.5 and 18.9 ° C at drying temperatures of 55, 65 and 75 ℃, respectively. Meanwhile 47.8, 42.9 and 40.9 percents of the dryer exhaust air energy were recovered respectively at these conditions which subsequently led to a reduction of 30.7, 19.2 and 14.7 percents in electrical heater energy consumption.

Development of an active solar crop dryer: design analysis and ...

African Journals Online (AJOL)

The design analysis and performance evaluation of an active solar crop dryer was undertaken by drying marched cassava. The drying rate, system drying, collector and pick-up efficiencies were 1.6kg/day (14%/day), 9%, 46% and 29% respectively. Comparatively, the drying rate for sun drying was 0.9kg/day. The collector ...

Vibration Analysis for Steam Dryer of APR1400 Steam Generator

Energy Technology Data Exchange (ETDEWEB)

Han, Sung-heum; Ko, Doyoung [KHNP CRI, Daejeon (Korea, Republic of); Cho, Minki [Doosan Heavy Industry, Changwon (Korea, Republic of)

2016-10-15

This paper is related to comprehensive vibration assessment program for APR1400 steam generator internals. According to U.S. Nuclear Regulatory Commission, Regulatory Guide 1.20 (Rev.3, March 2007), we conducted vibration analysis for a steam dryer as the second steam separator of steam generator internals. The vibration analysis was performed at the 100 % power operating condition as the normal operation condition. The random hydraulic loads were calculated by the computational fluid dynamics and the structural responses were predicted by power spectral density analysis for the probabilistic method. In order to meet the recently revised U.S. NRC RG 1.20 Rev.3, the CVAP against the potential adverse flow effects in APR1400 SG internals should be performed. This study conducted the vibration response analysis for the SG steam dryer as the second moisture separator at the 100% power condition, and evaluated the structural integrity. The predicted alternating stress intensities were evaluated to have more than 17.78 times fatigue margin compared to the endurance limit.

Performance of mechanically shaken indirect contact atmospheric dryer in drying pastelike materials

Directory of Open Access Journals (Sweden)

K. P. Melo

2004-09-01

Full Text Available Pastelike materials are encountered in many technological processes in chemical, pharmaceutical, foodstuff and natural product industries. The most important factor in the drying of this type of materials is the nature of the moisture bonding that occurs. Because of the different characteristics of pastes, it is impossible to recommend a universal type of dryer for all of these materials. Some of the dryers available provide only indirect contact with the drying agent (heat and also maintain constant moisture with a system of rotating paddles. We evaluated the performance of this type by studying the dryer kinetics curves for ground coffee under a variety of operational conditions of moisture load of material, temperature of the heating plate, intensity of the mechanical mixing of the moisture material, and initial moisture. The effects of these parameters (except for moisture were studied using a 2³ factorial design. According the analyses of the kinetics drying curves, was observed that the increase in the temperature of the plate and rotation as well as the decrease in the load facilitates more effective removal of moisture. In statistical analysis was determined that the load of the material and the heating plate temperature influence the final moisture content of the material and plate temperature modifies the final temperature of the solid. Also, was suggested linear models from the factorial design to describe the process of drying coffee grounds satisfactorily.

Optimization of annatto (Bixa orellana L. drying in fixed bed

Directory of Open Access Journals (Sweden)

Faria L.J.G.

2000-01-01

Full Text Available The drying of annatto seeds (Bixa orellana L., red piave cultivate, was studied in a fixed bed dryer. The best conditions were estimated to minimize the loss of coloring and to obtain final moisture of the seeds in appropriate levels to its conservation and maintenance of quality. The quantification of the influence of entrance variables in the final contents of bixin and moisture seeds and the identification of the optimal point was performed through the techniques of factorial design, response surfaces methodology, canonical analysis and desirability function. It was verified that the final moisture of the seeds may be estimated by a second-order polynomial model and that the final content of bixin is only significantly influenced by the time of drying being described properly by a linear model, for the seeds used in this study.

Life cycle energy metrics and CO 2 credit analysis of a hybrid photovoltaic/thermal greenhouse dryer

OpenAIRE

P. Barnwal; G. N. Tiwari

2008-01-01

In this paper, life cycle energy metrics, such as energy payback time (EPBT), energy production factor (EPF) and life cycle conversion efficiency (LCCE), and mitigation of CO 2 emissions for a hybrid photovoltaic/thermal (PV/T) greenhouse dryer have been analyzed. The hybrid PV/T greenhouse (roof type even span) dryer, designed and constructed at Solar Energy Park, Indian Institute of Technology, New Delhi (28°35′N, 77°12′E, 216 m above MSL), India, has a 2.50 m × 2.60 m floor area, 1.80 m ce...

Natural convection solar crop dryers in Kenya: Theory and practical application. African Energy Programme research report series no. 3

International Nuclear Information System (INIS)

Othieno, H.

1987-01-01

The African Energy Programme (AEP) was established by the Commonwealth Science Council (CSC) to strengthen Africa's scientific and technical capabilities to develop and utilise the continent's enormous renewable energy resources to assist its socio-economic development. The AEP was conceived at a regional workshop held at Arusha, Tanzania in 1979, at which African researchers met to share their experiences of and explored the feasibility of establishing a collaborative regional R and D programme to develop and adapt technologies appropriate to the specific needs of the participating countries. The AEP researchers accorded the highest priority to seeking solutions to the energy problems of Africa's predominantly rural populations and identified eight project areas as the nodes for regional collaborative research and development: 1. Biogas for rural development; 2. Wood/Charcoal production and utilisation; 3. Solar crop drying; 4. Solar thermal heating and cooling; 5. Wind electricity generation; 6. Wind water pumping; 7. Resources Assessments; 8. Energy policy and planning. The primary goal of the AEP activities were to develop indigenous national capabilities to enable the examination and application of technological solutions appropriate to the unique problems and socio-cultural environments of each country. However, the severe limitations on expertise and the broad similarity of many of the critical problems favoured regional R and D cooperation around common techniques and methodologies in each project area. This work has made a significant contribution to Science and Technology. Prior to this work there was no detailed information in natural convection solar dryers. This work has exposed a number of critical design factors which must be considered in order to design an efficient dryer. Buoyancy-induced pressure inside the dryer, problems of multiple radiative heat exchange in the heater and cooling effects of wind have been studied in detail. The final dryer

Natural convection solar crop dryers in Kenya: Theory and practical application. African Energy Programme research report series no. 3

Energy Technology Data Exchange (ETDEWEB)

Othieno, H [Kenyatta University, Nairobi (Kenya)

1987-07-01

The African Energy Programme (AEP) was established by the Commonwealth Science Council (CSC) to strengthen Africa's scientific and technical capabilities to develop and utilise the continent's enormous renewable energy resources to assist its socio-economic development. The AEP was conceived at a regional workshop held at Arusha, Tanzania in 1979, at which African researchers met to share their experiences of and explored the feasibility of establishing a collaborative regional R and D programme to develop and adapt technologies appropriate to the specific needs of the participating countries. The AEP researchers accorded the highest priority to seeking solutions to the energy problems of Africa's predominantly rural populations and identified eight project areas as the nodes for regional collaborative research and development: 1. Biogas for rural development; 2. Wood/Charcoal production and utilisation; 3. Solar crop drying; 4. Solar thermal heating and cooling; 5. Wind electricity generation; 6. Wind water pumping; 7. Resources Assessments; 8. Energy policy and planning. The primary goal of the AEP activities were to develop indigenous national capabilities to enable the examination and application of technological solutions appropriate to the unique problems and socio-cultural environments of each country. However, the severe limitations on expertise and the broad similarity of many of the critical problems favoured regional R and D cooperation around common techniques and methodologies in each project area. This work has made a significant contribution to Science and Technology. Prior to this work there was no detailed information in natural convection solar dryers. This work has exposed a number of critical design factors which must be considered in order to design an efficient dryer. Buoyancy-induced pressure inside the dryer, problems of multiple radiative heat exchange in the heater and cooling effects of wind have been studied in detail. The final dryer

Drying of Rhinacanthus nasutus (Linn. Kurz. using a solar dryer incorporated with a backup thermal energy storage from wood combustion

Directory of Open Access Journals (Sweden)

Perapong Tekasakul

2006-05-01

Full Text Available An indirect, natural convection, solar cabinet dryer incorporated with a backup thermal energy storage from wood combustion was designed and tested with the Thai herb, Rhinacanthus nasutus (Linn. Kurz. Most of Thai herbs are widely used as traditional medicine and drying is an initial step in the production process. Solar dryer with a biomass backup heating system is the most feasible solution to drying in Thailand. In this work, a 4 m x 5 m solar collector was used to absorb solar radiation for heating the incoming air during the daytime, while a biomass burner was used to supply heat when solar energy was not possible. Heat from fuelwood combustion was accumulated in the thermal storage system made of bricks, and was used to heat up the incoming air. Results showed that the herb was dried uniformly and the temperature inside the drying cabinet could be maintained above 50ºC for more than 10 hours. Thermal efficiency when using solar energy was 10.5%, but the value was less than 1% when using the heat from biomass burning. This resulted from the low moisture content of the products after being dried by the solar energy. The dryer is beneficial to the operators, particularly in southern Thailand, where continuous drying is required. This dryer is by no means limited to drying of the herb. Currently, four dryers of the same model have been used by farmer groups in southern Thailand for drying bananas, several types of herbs, fish, and other products. In economic consideration, its payback period is 5.5 years when compared with the LPG-equipped dryer. When the total cost and production capacity are considered, its payback period is about 6 years.

Sanitary condition of electrical hand dryers in toilets of shopping centres in Kraków

Directory of Open Access Journals (Sweden)

Anna Lenart-Boroń

2015-06-01

Full Text Available Introduction. Shopping habits have changed over the past several years and consumers choose shopping centres, where they can spend time and visit restaurants. People usually wash hands before meals, but toilets in shopping centres are visited by hundreds of users every day which makes their cleanliness questionable. Therefore, the aim of this study was to assess the sanitary condition of electrical hand dryers in toilets of the selected shopping centres in Kraków. Material and methods. Air was sampled at the outlet of electrical hand dryers and surface swabs of hand dryers were taken in toilets of five shopping centres. Air sampling was conducted using the MAS-100 impactor. The number of mesophilic bacteria, fungi, actinomycetes, staphylococci and Escherichia coli was determined. The results of air analyses were compared with the limits provided by the Polish Standards on air quality. Results. The number of microorganisms varied between the studied centres. In terms of mesophilic bacteria and fungi the air was unpolluted. The concentration of actinomycetes however significantly exceeded the limits set by the Polish Standards. Numerous Escherichia coli were found both in the air and in swabs in one of the centres. However the number of E. coli and staphylococci did not exceed the minimum infective dose. Conclusions. The studies showed high concentrations of airborne actinomycetes and staphylococci. Also the presence of E. coli in the air and swabs allows the conclusion that legal regulations for concentrations of airborne microorganisms are necessary to make people aware of this problem. However, it was found that using electrical hand dryers does not have impact on human health.

The determination of carbon dioxide concentration using atmospheric pressure ionization mass spectrometry/isotopic dilution and errors in concentration measurements caused by dryers.

Science.gov (United States)

DeLacy, Brendan G; Bandy, Alan R

2008-01-01

An atmospheric pressure ionization mass spectrometry/isotopically labeled standard (APIMS/ILS) method has been developed for the determination of carbon dioxide (CO(2)) concentration. Descriptions of the instrumental components, the ionization chemistry, and the statistics associated with the analytical method are provided. This method represents an alternative to the nondispersive infrared (NDIR) technique, which is currently used in the atmospheric community to determine atmospheric CO(2) concentrations. The APIMS/ILS and NDIR methods exhibit a decreased sensitivity for CO(2) in the presence of water vapor. Therefore, dryers such as a nafion dryer are used to remove water before detection. The APIMS/ILS method measures mixing ratios and demonstrates linearity and range in the presence or absence of a dryer. The NDIR technique, on the other hand, measures molar concentrations. The second half of this paper describes errors in molar concentration measurements that are caused by drying. An equation describing the errors was derived from the ideal gas law, the conservation of mass, and Dalton's Law. The purpose of this derivation was to quantify errors in the NDIR technique that are caused by drying. Laboratory experiments were conducted to verify the errors created solely by the dryer in CO(2) concentration measurements post-dryer. The laboratory experiments verified the theoretically predicted errors in the derived equations. There are numerous references in the literature that describe the use of a dryer in conjunction with the NDIR technique. However, these references do not address the errors that are caused by drying.

Chitosan microspheres loaded with holmium-165 produced by spray dryer for liver cancer therapy: preliminary experiments

International Nuclear Information System (INIS)

Miyamoto, Douglas Massao; Pires, Geovanna; Lira, Raphael A. de; Melo, Vitor H.S.; Nascimento, Nanci; Azevedo, Mariangela de Burgos M. de; Osso Junior, Joao Alberto

2011-01-01

Chitosan is a biopolymer of 2-deoxy-2-amino-D-glucose that is obtained by deacetylation of chitin. It's biocompatible, biodegradable, non toxic and has antitumor activity. Chitosan has many applications, such as their microparticles that can be used to treat prostate cancer, rheumatoid arthritis, and for liver tumor brachytherapy treatment. Our group is developing different biodegradable polymer-based microspheres loaded with holmium-165 for this purpose. The Chitosan microspheres were produced loaded with holmium (III) chloride, and not loaded with it, by Mini Spray Dryer procedure. The microspheres were evaluated by scanning electron microscopy, energy dispersive spectroscopy (EDS), confocal laser scanning microscopy, thermogravimetric analysis, particle size, and X-ray diffraction. The EDS analysis confirmed the holmium chloride presence into the prepared chitosan microparticles. (author)

Chitosan microspheres loaded with holmium-165 produced by spray dryer for liver cancer therapy: preliminary experiments

Energy Technology Data Exchange (ETDEWEB)

Miyamoto, Douglas Massao; Pires, Geovanna; Lira, Raphael A. de; Melo, Vitor H.S.; Nascimento, Nanci; Azevedo, Mariangela de Burgos M. de, E-mail: douglas.miyamoto@usp.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Osso Junior, Joao Alberto [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Radiofarmacia

2011-07-01

Chitosan is a biopolymer of 2-deoxy-2-amino-D-glucose that is obtained by deacetylation of chitin. It's biocompatible, biodegradable, non toxic and has antitumor activity. Chitosan has many applications, such as their microparticles that can be used to treat prostate cancer, rheumatoid arthritis, and for liver tumor brachytherapy treatment. Our group is developing different biodegradable polymer-based microspheres loaded with holmium-165 for this purpose. The Chitosan microspheres were produced loaded with holmium (III) chloride, and not loaded with it, by Mini Spray Dryer procedure. The microspheres were evaluated by scanning electron microscopy, energy dispersive spectroscopy (EDS), confocal laser scanning microscopy, thermogravimetric analysis, particle size, and X-ray diffraction. The EDS analysis confirmed the holmium chloride presence into the prepared chitosan microparticles. (author)

COMMERCIAL DEMONSTRATION OF THE MANUFACTURED AGGREGATE PROCESSING TECHNOLOGY UTILIZING SPRAY DRYER ASH

Energy Technology Data Exchange (ETDEWEB)

Roy Scandrol

2003-10-01

Universal Aggregates, LLC proposes to design, construct and operate a lightweight aggregate manufacturing plant at the Birchwood Power Facility in King George, Virginia. The installation and start-up expenses for the Birchwood Aggregate Facility are $19.5 million. The DOE share is $7.2 million (37%) and the Universal Aggregates share is $12.3 (63%). The project team consists of CONSOL Energy Inc., P.J. Dick, Inc., SynAggs, LLC, and Universal Aggregates, LLC. The Birchwood Facility will transform 115,000 tons per year of spray dryer by-products that are currently being disposed of in an offsite landfill into 167,000 tons of a useful product, lightweight aggregates that can be used to manufacture lightweight aggregates that can be used to manufacture lightweight and medium weight masonry blocks. In addition to the environmental benefits, the Birchwood Facility will create nine (9) manufacturing jobs plus additional employment in the local trucking industry to deliver the aggregate to customers or reagents to the facility. A successful demonstration would lead to additional lightweight aggregate manufacturing facilities in the United States. There are currently twenty-one (21) spray dryer facilities operating in the United States that produce an adequate amount of spray dryer by-product to economically justify the installation of a lightweight aggregate manufacturing facility. Industry sources believe that as additional scrubbing is required, dry FGD technologies will be the technology of choice. Letters from potential lightweight aggregate customers indicate that there is a market for the product once the commercialization barriers are eliminated by this demonstration project.

COMMERCIAL DEMONSTRATION OF THE MANUFACTURED AGGREGATE PROCESSING TECHNOLOGY UTILIZING SPRAY DRYER ASH

Energy Technology Data Exchange (ETDEWEB)

Roy Scandrol

2003-04-01

Universal Aggregates, LLC proposes to design, construct and operate a lightweight aggregate manufacturing plant at the Birchwood Power Facility in King George, Virginia. The installation and start-up expenses for the Birchwood Aggregate Facility are $19.5 million. The DOE share is $7.2 million (37%) and the Universal Aggregates share is $12.3 (63%). The project team consists of CONSOL Energy Inc., P.J. Dick, Inc., SynAggs, LLC, and Universal Aggregates, LLC. The Birchwood Facility will transform 115,000 tons per year of spray dryer by-products that are currently being disposed of in an offsite landfill into 167,000 tons of a useful product, lightweight aggregates that can be used to manufacture lightweight aggregates that can be used to manufacture lightweight and medium weight masonry blocks. In addition to the environmental benefits, the Birchwood Facility will create eight (8) manufacturing jobs plus additional employment in the local trucking industry to deliver the aggregate to customers or reagents to the facility. A successful demonstration would lead to additional lightweight aggregate manufacturing facilities in the United States. There are currently twenty-one (21) spray dryer facilities operating in the United States that produce an adequate amount of spray dryer by-product to economically justify the installation of a lightweight aggregate manufacturing facility. Industry sources believe that as additional scrubbing is required, dry flue gas desulfurization (FGD) technologies will be the technology of choice. Letters from potential lightweight aggregate customers indicate that there is a market for the product once the commercialization barriers are eliminated by this demonstration project.

Development of drying equipment for heat sensitive material : final report

Energy Technology Data Exchange (ETDEWEB)

Schoenau, G.J.; Sokhansanj, S. [Saskatchewan Univ., Saskatoon, SK (Canada)

2003-07-01

This paper described a project in which two types of prototype heat pump dryer systems were designed, constructed and field tested in 2000 to 2002. Performance testing was accomplished through a computer based simulation model for predicting dryer performance. The paper describes the procedures followed and the results obtained. The dryer is used for high value specialty crops such as ginseng, herbs and echinacea which require low temperature drying. The heat pump dryer operates under a closed loop and can dry these crops at low temperatures, independent of ambient conditions. The first prototype was a small fixed bed cabinet dryer suitable for small growers. The other was a full scale prototype moving bed cross flow system suitable for large scale commercial drying of sensitive agricultural crops. The heat pump system is faster and more energy efficient than conventional dryers. The average moisture content of ginseng roots was reduced by 10 per cent in 5 days using 190 kWh of energy. The heat pump dryer is 22 per cent more efficient than a conventional dryer due to its recirculating system. Drying time is reduced by 65 per cent. A computerized simulation validated experimental results. 30 refs., 10 tabs., 29 figs.

Evaluating the parameters of a mobile maize dryer in practice

Directory of Open Access Journals (Sweden)

Josef Los

2013-01-01

Full Text Available The method of drying maize for grain has been recently employed on a large scale in the Czech Republic not only thanks to new maize hybrids but also thanks to the existence of new models of drying plants. One of the new post-harvest lines is a plant in Lipoltice (mobile dryer installed in 2010, storage base in 2012 where basic operational measurements were made of the energy intensiveness of drying and operating parameters of the maize dryer were evaluated. The process of maize drying had two stages, i.e. pre-drying from the initial average grain humidity of 28.55% to 19.6% in the first stage, and the additional drying from 16.7% to a final storage grain humidity of 13.7%. Mean volumes of natural gas consumed per 1 t% for drying in the first and second stage amounted to 1.275 m3 and 1.56 m3, respectively. The total mean consumption of electric energy per 1 t% was calculated to be 1.372 kWh for the given configuration of the post-harvest line.

Impact of flow induced vibration acoustic loads on the design of the Laguna Verde Unit 2 steam dryer

International Nuclear Information System (INIS)

Forsyth, D. R.; Wellstein, L. F.; Theuret, R. C.; Han, Y.; Rajakumar, C.; Amador C, C.; Sosa F, W.

2015-09-01

Industry experience with Boiling Water Reactors (BWRs) has shown that increasing the steam flow through the main steam lines (MSLs) to implement an extended power up rate (EPU) may lead to amplified acoustic loads on the steam dryer, which may negatively affect the structural integrity of the component. The source of these acoustic loads has been found to be acoustic resonance of the side branches on the MSLs, specifically, coupling of the vortex shedding frequency and natural acoustic frequency of safety relief valves (SRVs). The resonance that results from this coupling can contribute significant acoustic energy into the MSL system, which may propagate upstream into the reactor pressure vessel steam dome and drive structural vibration of steam dryer components. This can lead to high-cycle fatigue issues. Lock-in between the vortex shedding frequency and SRV natural frequency, as well as the ability for acoustic energy to propagate into the MSL system, are a function of many things, including the plant operating conditions, geometry of the MSL/SRV junction, and placement of SRVs with respect to each other on the MSLs. Comision Federal de Electricidad and Westinghouse designed, fabricated, and installed acoustic side branches (ASBs) on the MSLs which effectively act in the system as an energy absorber, where the acoustic standing wave generated in the side-branch is absorbed and dissipated inside the ASB. These ASBs have been very successful in reducing the amount of acoustic energy which propagates into the steam dome. In addition, modifications to the Laguna Verde Nuclear Power Plant Unit 2 steam dryer have been completed to reduce the stress levels in critical locations in the dryer. The objective of this paper is to describe the acoustic side branch concept and the design iterative processes that were undertaken at Laguna Verde Unit 2 to achieve a steam dryer design that meets the guidelines of the American Society of Mechanical Engineers, Boiler and Pressure

Impact of flow induced vibration acoustic loads on the design of the Laguna Verde Unit 2 steam dryer

Energy Technology Data Exchange (ETDEWEB)

Forsyth, D. R.; Wellstein, L. F.; Theuret, R. C.; Han, Y.; Rajakumar, C. [Westinghouse Electric Company LLC, Cranberry Township, PA 16066 (United States); Amador C, C.; Sosa F, W., E-mail: forsytdr@westinghouse.com [Comision Federal de Electricidad, Central Nucleoelectrica Laguna Verde, Km 42.5 Carretera Cardel-Nautla, 91680 Alto Lucero, Veracruz (Mexico)

2015-09-15

Industry experience with Boiling Water Reactors (BWRs) has shown that increasing the steam flow through the main steam lines (MSLs) to implement an extended power up rate (EPU) may lead to amplified acoustic loads on the steam dryer, which may negatively affect the structural integrity of the component. The source of these acoustic loads has been found to be acoustic resonance of the side branches on the MSLs, specifically, coupling of the vortex shedding frequency and natural acoustic frequency of safety relief valves (SRVs). The resonance that results from this coupling can contribute significant acoustic energy into the MSL system, which may propagate upstream into the reactor pressure vessel steam dome and drive structural vibration of steam dryer components. This can lead to high-cycle fatigue issues. Lock-in between the vortex shedding frequency and SRV natural frequency, as well as the ability for acoustic energy to propagate into the MSL system, are a function of many things, including the plant operating conditions, geometry of the MSL/SRV junction, and placement of SRVs with respect to each other on the MSLs. Comision Federal de Electricidad and Westinghouse designed, fabricated, and installed acoustic side branches (ASBs) on the MSLs which effectively act in the system as an energy absorber, where the acoustic standing wave generated in the side-branch is absorbed and dissipated inside the ASB. These ASBs have been very successful in reducing the amount of acoustic energy which propagates into the steam dome. In addition, modifications to the Laguna Verde Nuclear Power Plant Unit 2 steam dryer have been completed to reduce the stress levels in critical locations in the dryer. The objective of this paper is to describe the acoustic side branch concept and the design iterative processes that were undertaken at Laguna Verde Unit 2 to achieve a steam dryer design that meets the guidelines of the American Society of Mechanical Engineers, Boiler and Pressure

Process analysis of biofuelled heat and power plants integrated with a flue gas dryer; Processtudie av biobraensleeldade kraftvaermeverk integrerade med roekgastork

Energy Technology Data Exchange (ETDEWEB)

Johansson, Kent; Steinwall, Pontus [Sycon Energikonsult AB, Malmoe (Sweden)

2000-01-01

In this report three different processes for combined heat and power production from biomass have been evaluated and compared. Both economical and technical questions have been investigated. The examined processes are: 1. CFB fuelled with wet biomass; 2. A boiler fuelled with pulverised biomass integrated with a traditional flue gas dryer; and 3. A boiler fuelled with pulverized biomass integrated with a flue gas dryer with a closed loop. All the processes have a district heat output of 80 MW. Calculations have been made at three different loads: 100, 70 and 40 % respectively. The performance characteristics in form of electric efficiency and fuel utilisation are very similar for the processes. To evaluate the thermodynamic differences between the processes, calculations have been made with extreme temperatures in the district heating net, 65 deg C/100 deg C. The process with a closed loop drier has a saturation temperature in the flue gas of 95 deg C. Therefore this process has a high fuel utilization even if the incoming water has a high temperature. The fuel utilization for alternatives 1 and 2 decreases almost down to the efficiency of the furnace. This shows that the temperature of the water is too high to recapture the latent heat in the flue gases. The investment costs for the processes have been estimated. Also these are very similar for the three alternatives. The cost for the process with the CFB is 412 million SEK. The boiler in alternative 2 and 3 is approximately 20 million SEK cheaper than the CFB. The decreased cost for the boiler is compensated by the cost for the dryers. The investment cost for the traditional dryer has been estimated to 20 million SEK and 30 million SEK for the closed loop dryer. The total cost for alternative 2 is then 417 million SEK and 414 million SEK for alternative 3. Operation and maintenance costs for the processes with dryer are supposed to be 1 respectively 1.5 million SEK higher than for alternative 1. The dryers may

A novel rate of the reaction between NaOH with CO2 at low temperature in spray dryer

Directory of Open Access Journals (Sweden)

Yadollah Tavan

2017-03-01

Full Text Available Carbon dioxide (CO2 is an influential greenhouse gas that has a significant impact on global warming partly. Nowadays, many techniques are available to control and remove CO2 in different chemical processes. Since the spray dryer has high removal efficiency rate, a laboratory-scale spray dryer is used to absorb carbon dioxide from air in aqueous solution of NaOH. In the present study, the impact of NaOH concentration, operating temperature and nozzle diameter on removal efficiency of CO2 is explored through experimental study. Moreover, the reaction kinetic of NaOH with CO2 is studied over the temperature range of 50–100 °C in a laboratory-scale spray dryer absorber. In the present contribution, a simple reaction rate equation is proposed that shows the lowest deviation from the experimental data with error less than 2%.

ANALISIS KELAYAKAN TEKNIS DAN FINANSIAL DARI INVESTASI PENGADAAN TRAY DRYER BERBAHAN BAKAR BIOMASSA PADA USAHA ARANG TEMPURUNG KELAPA BERBASIS EKSPOR (Studi Kasus di Tropica Nucifera Industry – Yogyakarta

Directory of Open Access Journals (Sweden)

Fanny Widadie

2013-11-01

Full Text Available The purpose of the study is to assess the technical and financial feasibility of procurement investment Tray Dryer fueled biomass to operations of coconut shell charcoal briquette in PT. Tropica Nucifera Industry. The result showed that investment-Tray Dryer on cocnut shell charcoal briquette bussiness was highly feasibile both the technical and financial aspects. The technical aspect was seen that the quantity-production capabilities of coconut shell charcoal briquettes using a dryer-Tray Dryer could be increased 15 percent compared the previous consdition-used of solar energy. While the quality of the charcoal briquettes produced from Tray Dryer was a much butter quality, moisture content (6.39%; ash (2.65%; carbon-bound (85.83%, compared to using sunlight, water content (15.89; ash (2.57% and carbon-bound (77.32%.The financial aspects of procurement Tray Dryer investment that its value was more feasible than previous, nothing Tray Dryer. Coconut shell charcoal briquet enterprises without using Tray Dryer was feasible to be done with NPV 1,058,928.12, IRR 63%, Payback Period 1 year and 9 moths, Net B/C 2.25 and analysis of swicthcing value reached 20 percent. And after the business using Tray Drayer, the financial analysis was much more feasible with NPV 2,285,500,498.12, IRR 113%, Payback Period 11 months, Net B/C 3.5 and analysis of switching value reached 50 percent.

Experimental investigation and thermodynamic performance analysis of a solar dryer using an evacuated-tube air collector

International Nuclear Information System (INIS)

Lamnatou, Chr.; Papanicolaou, E.; Belessiotis, V.; Kyriakis, N.

2012-01-01

Highlights: ► We evaluate an evacuated-tube solar air collector and use it to develop a novel dryer. ► Apple, carrot and apricot thin-layer drying experiments are conducted. ► Best overall fitting among several available thin-layer drying models is pursued. ► Thermodynamic analysis yields optimal collector area, energy utilization/exergy loss. ► The proposed dryer has a capacity for drying larger quantities of products. -- Abstract: The present work presents a thermodynamic performance analysis of a solar dryer with an evacuated-tube collector. Drying experiments for apples, carrots and apricots were conducted, after a preliminary stage of the investigation which included measurements for the determination of the collector efficiency. These results showed that the warm outlet air of the collector attains temperature levels suitable for drying of agricultural products without the need of preheating. Thus, the present collector was used as the heat source for a drying chamber in the frame of the development of a novel, convective, indirect solar dryer; given the fact that in the literature there are only a few studies about this type of collectors in conjunction with solar drying applications. Thin-layer drying models were fitted to the experimental drying curves, including the recent model of Diamante et al. which showed good correlation coefficients for all the tested products. Drying parameters such as moisture ratio and drying rates were calculated. Furthermore, an energetic/exergetic analysis of the dryer was also conducted and performance coefficients such as pick-up and exergy efficiencies, energy utilization ratio, exergy losses were determined for several configurations such as single and double-trays and several drying air velocities. On the other hand, an optimal collector surface area study was conducted, based on laws for minimum entropy generation. Design parameters such as optimum collector area were determined based on the minimum entropy

Saving energy. [Metal Coating With Infrared Dryers

Energy Technology Data Exchange (ETDEWEB)

Schmid, K

1981-01-01

One way of saving energy in metal coating is by using electrically heated infrared dryers with medium-wave radiation (2 to 3 ..mu..m). The absorbing capacity of varnishes and plastic coatings is >90% in this range so that the radiation energy is almost completely transformed into heat. Medium-wave radiation sources have a much higher service life than short-wave sources (30.000 hours of operation) and do not require cooling; compared with long-wave sources, they have a higher heat transfer and thus much shorter drying times. The main fields of application, a cost example, and practical examples among the customers of Messrs. Eisenmann are presented.

Design and Performance Evaluation of a Solar Assisted Heat Pump Dryer Integrated with Biomass Furnace for Red Chilli

Directory of Open Access Journals (Sweden)

M. Yahya

2016-01-01

Full Text Available The performance of a solar assisted heat pump dryer integrated with biomass furnace has been designed and evaluated for drying red chillies, and drying kinetics of red chillies were evaluated. The red chillies were dried from 22 kg with moisture content of 4.26 db to moisture content of 0.08 db which needed 11 hours, with the average drying chamber temperature, drying chamber relative humidity, and an air mass flow rate of 70.5°C, 10.1%, and 0.124 kg/s, respectively, while the open sun drying needed 62 hours. Compared to open sun drying, this dryer yielded 82% saving in drying time. The drying rate, the specific moisture extraction rate, and thermal efficiency of the dryer were estimated in average to be about 1.57 kg/h, 0.14 kg/kWh, and 9.03%, respectively. Three mathematical models, the Newton, Henderson-Pabis, and Page models, were fitted to the experimental data on red chillies dried by solar assisted heat pump dryer integrated with biomass furnace and open sun drying. The performance of these models was evaluated by comparing the coefficient of determination (R2, mean bias error (MBE, and root mean-square error (RMSE. The Page model gave the best results for representing drying kinetics of red chillies.

Modelling of hot air chamber designs of a continuous flow grain dryer

DEFF Research Database (Denmark)

Kjær, Lotte Strange; Poulsen, Mathias; Sørensen, Kim

2018-01-01

The pressure loss, flow distribution and temperature distribution of a number of designs of the hot air chamber in a continuous flow grain dryer, were investigated using CFD. The flow in the dryer was considered as steady state, compressible and turbulent. It is essential that the grain...... is uniformly dried as uneven drying can result in damage to the end-product during storage. The original commercial design was modified with new guide vanes at the inlets to reduce the pressure loss and to ensure a uniform flow to the line burner in the hot air chamber. The new guide vane design resulted...... in a 10% reduction in pressure loss and a γ-value of 0.804. Various design changes of the hot air chamber were analysed in terms of pressure loss and temperature distribution with the aim of a temperature variation of 5 K at the outlet ducts. An obstruction design was analysed, which improved mixing...

Design aspects of integrated compact thermal storage system for solar dryer applications

International Nuclear Information System (INIS)

Rajaraman, R.; Velraj, R.; Renganarayanan, S.

2000-01-01

Solar energy is an excellent source for drying of crops, fruits, vegetables and other agricultural and forest products. Though the availability of solar energy is plenty, it is time dependent in nature. The energy need for some applications is also time dependent, but in a different pattern and phase from the solar energy supply. This implies that the solar dryer should be integrated with an efficient thermal storage system to match the time-dependent supply and end-use requirements. Based on the studies carried out on Latent Heat Thermal Storage (LHTS) Systems, it is observed that when air is used as the heat transfer fluid in LHTS system, nearly uniform surface heat flux can be achieved. Hence the LHTS systems are most suitable for air based solar drying applications. In the present work some major conclusions arrived from the investigations on LHTS systems and the design considerations for the integrated latent heat thermal storage for the solar dryer are reported. (Author)

Drying of Rosella (Hibiscus sabdariffa Flower Petals using Solar Dryer with Double Glass Cover Collector

Directory of Open Access Journals (Sweden)

Tjukup Marnoto

2014-10-01

Full Text Available Chemical ingredients in rosella petals are very beneficial for health. Rosella petals needed to be drained for storage and packing purpose. The traditional drying takes 5 days and less healthy. Solar dryer technology can speed up the drying process and protect materials from dust contamination. Solar dryer with double glass covered collector has been designed and made for drying of agricultural products such as rosella flowers. Rosella petals as much as 2300 grams with initial moisture content of 90.84 % be dried with this dryer until the moisture content of 7.67 % takes only 2 days, although the weather was less sunny . The temperature in the drying chamber was not more than 50° C, so it was good for drying groceries, not damaging chemical ingredients. The relative humidity in the space dryeris was about 40 % and it was still relative low. Drying rate and drying performance was expressed by the efficiency and Specific Moisture Evaporation Rate ( SMER were influenced by water content of the dried material and weather. Daily efficiency at the first and the second day: 14.931 % and 5.78%, while the daily SMER on the first and the second day: 0.222 and 0.0256 ( kg / kWh .

Final Report: Laboratory Development of a High Capacity Gas-Fired Paper Dryer

Energy Technology Data Exchange (ETDEWEB)

Yaroslav Chudnovsky; Aleksandr Kozlov; Lester Sherrow

2005-09-30

Paper drying is the most energy-intensive and temperature-critical aspect of papermaking. It is estimated that about 67% of the total energy required in papermaking is used to dry paper. The conventional drying method uses a series of steam-heated metal cylinders that are required to meet ASME codes for pressure vessels, which limits the steam pressure to about 160 psig. Consequently, the shell temperature and the drying capacity are also limited. Gas Technology Institute together with Boise Paper Solutions, Groupe Laperrier and Verreault (GL&V) USA Inc., Flynn Burner Corporation and with funding support from the U.S. Department of Energy, U.S. natural gas industry, and Gas Research Institute is developing a high efficiency gas-fired paper dryer based on a combination of a ribbon burner and advanced heat transfer enhancement technique. The Gas-Fired Paper Dryer (GFPD) is a high-efficiency alternative to conventional steam-heated drying drums that typically operate at surface temperatures in the 300 deg F range. The new approach was evaluated in laboratory and pilot-scale testing at the Western Michigan University Paper Pilot Plant. Drum surface temperatures of more than 400 deg F were reached with linerboard (basis weight 126 lb/3000 ft2) production and resulted in a 4-5 times increase in drying rate over a conventional steam-heated drying drum. Successful GFPD development and commercialization will provide large energy savings to the paper industry and increase paper production rates from dryer-limited (space- or steam-limited) paper machines by an estimated 10 to 20%, resulting in significant capital costs savings for both retrofits and new capacity.

76 FR 22453 - Energy Conservation Program: Energy Conservation Standards for Residential Clothes Dryers and...

Science.gov (United States)

2011-04-21

... Mode and Off Mode b. Automatic Cycle Termination c. Ventless Clothes Dryers d. Consumer Usage Habits e... as cooling capacity in British thermal units (Btu) per hour (h) divided by electrical input power in...

Spouted bed drying of Bauhinia forficata link extract: the effects of feed atomizer position and operating conditions on equipment performance and product properties

Directory of Open Access Journals (Sweden)

C. R. F. Souza

2005-06-01

Full Text Available In this paper the effects of feed atomizer position and operating conditions on equipment performance (accumulation rate, product recovery, elutriation and thermal efficiency and product properties (moisture content, size distribution, flavonoid degradation and flow properties during spouted bed drying of Bauhinia forficata Link extract are evaluated. The parameters studied were the position of the atomizer system (top spray or bottom spray, the inlet temperature of the spouting gas (80 and 150oC and the feed mass flow rate of concentrated extract relative to the evaporation capacity of the dryer, Ws/Wmax (15 to 100%. Higher accumulation rate values were obtained with the atomizer placed at the bottom of the bed. In this configuration, the accumulation rate increases with the increase in the Ws/Wmax ratio. The best drying performance was obtained for the top spray configuration.

Reactive collisions of electrons with H2+ , HD+, BeH+, BeD+ and SH+

Science.gov (United States)

Pop, Nicolina; Iacob, Felix; Mezei, János Zsolt; Motapon, Ousmanou; Niyonzima, Sebastien; Kashinski, David O.; Talbi, Dahbia; Hickman, Albert Peet; Schneider, Ioan F.

2017-12-01

In numerous cold ionized gases the dissociative recombination (DR), the elastic collisions (EC), the vibrational excitation (VE) (inelastic collisions) and the vibrational de-excitation (VdE) (super-elastic collisions) of molecular cations with electrons are major elementary processes. Using a stepwise method based on the Multichannel Quantum Defect Theory (MQDT), cross sections and rate coefficients have been obtained for reactions induced on HD+, H2+, BeH+, BeD+ and SH+. Moreover, the relative importance of the different reaction mechanisms, direct vs. indirect and rotational vs. non-rotational, have been studied for these molecular systems.

Evaluation of an industrial gas-fired IR dryer; Utvaerdering av en industriell gaseldad IR-straalare

Energy Technology Data Exchange (ETDEWEB)

Stenstroem, S; Hermodsson, S

1994-11-01

The IR dryer is used in a paper making machine to dry the paper web after it has been coated with a surface layer. In part 1 of the project a mathematical model have been developed, capable of calculating the radiation intensity and other energy flows in the dryer. In part 2 of the project, measurements have been made on the IR radiator mounted in the paper making machine. The calculation model shows the efficiency of the radiator to 39% at full power and 35% at half power. The direct measurements were made at half power and gave an efficiency of 31% for new radiators and 28% for old ones. The conclusion is that the calculation model values corresponds very well compared with direct measurements.

Numerical calculations of heat engineering parameters of a solar greenhouse dryer

International Nuclear Information System (INIS)

Akhatov, Zh.S.; Khalimov, A.S.

2015-01-01

The results of numerical simulation to determine the optimum volume of a thermal storage water heater in a solar greenhouse dryer are presented. A CAD (computer-aided design) model is created for the given installation by simulating the heat transfer processes with the aid of the Solid Works Flow Simulation software. The given CAD model consists of a concrete foundation and a steel frame in which translucent coatings made from two-layer polycarbonate sheets 6 mm in thickness with an air gap between the two layers are attached. The north wall is made of bricks with size and thickness of 2 x 4 m"2 and 0.4 m, respectively. The front surface has an angle of inclination 39.53 degree with respect to the horizontal surface for the maximum incidence of solar radiation to its surface. All the geometrical dimensions of the solar greenhouse dryer were selected on the basis of the allocated platform for the solar drying installation 3 x 4 m"2 in size. It is shown that the optimum volume of the heat storage tank for the present installation is 500 L. (authors)

Effect of brining on the drying rate of tilapia in a solar tunnel dryer

Energy Technology Data Exchange (ETDEWEB)

Kituu, G.M.; Shitanda, D.; Kanali, C.L.; Mailutha, J.T. [Jomo Kenyatta Univ. of Agriculture and Technology, Nairobi (Kenya). BEED

2008-07-01

In addition to being a source of protein, fish is an important source of local and foreign currency earnings in Kenya. A substantial amount of fish production is exported. Approximately 30 per cent is exported to the European Union, the United States, and countries in the Middle East, but nearly half of the total annual fish harvest in Kenya goes to waste due to poor processing and preservation. Measures must be taken to ensure the fish industry is protected and waste is minimized, since the livelihood of over 500,000 people depends on fish as a source of proteins and employment. Therefore, it is necessary to implement appropriate and affordable processing and preservation techniques for fish at the artisanal landing sites in order to reduce the wastage and spoilage of fish during oversupply, and to enhance long storage. This paper presented studies that were conducted to determine the effect of brining on the drying rate of tilapia in a solar tunnel dryer. The paper discussed the materials and methods, including a description of the solar tunnel dryer system; the brining process of fish; the fish drying process; and data analysis. It was concluded that limiting the amount of salt used in brining, and subsequently dehydrating fish with a solar tunnel dryer achieves a more stable and suitable dried fish product than osmotic dehydration or solar drying process separately. 19 refs., 5 figs., 2 appendices.

Analysis and Testing of a Natural Convection Solar Dryer for the Tropics

Directory of Open Access Journals (Sweden)

A. O. Adelaja

2013-01-01

Full Text Available Solar dryers are imperative for the tropical and sub-Saharan African countries, which are faced with the duo challenges of inadequate electrical energy supply, which has severely limited the application of conventional refrigeration as a means of preservation of agricultural produce, and the need to make produce competitive in the international market. In this study, a cost-effective natural convection solar dryer was developed; the thermal and drying analyses were done and tested to obtain some performance evaluation parameters for the system in order to examine its efficiency and effectiveness by drying some plantain fillets. The collector and system efficiencies are found to be 46.4% and 78.73%, respectively, while a percentage moisture removal of 77.5% was achieved at the 20th hour in order to give final moisture contents of 15.75% in the product, which still maintained its integrity. With a cost of about $195.00, it has been affordable for the small- and medium-scale enterprises as well as for private use in domestic applications.

Mathematical modeling of a mixed flow spray dryer

International Nuclear Information System (INIS)

Kasiri, N.; Delkhan, F.

2001-01-01

In this paper a mathematical model has been developed to simulate the behavior of spray dryers with an up-flowing spray. The model is based on mass, energy and momentum balance on a single droplet , and mass and energy balances on the drying gas. The system of nonlinear differential equations thus obtained is solved to predict the changes in temperature, humidity, diameter, velocity components and the density of the droplets as well as the temperature and the humidity changes of the drying gas. The predicted results were then compared with an industrially available set of results. A good degree of proximity between the two is reported

A fluidized bed furnace fired with biomass waste to supply heat for a spray dryer in a plant producing floortiles

Energy Technology Data Exchange (ETDEWEB)

Gulyurtlu, I.; Andre, R.; Mendes, J.; Monteiro, A.; Cabrita, I. [Instituto Nacional de Engenharia e Tecnologia Industrial, Lisboa (Portugal)

1993-12-31

This project has been implemented at a factory producing floortiles for domestic use. The project consists of a fluidized bed combustion system burning coal or wood or a mixture of both to produce hot combustion gases to provide heat for spray drying process. The system was designed by INETI for a maximum output of 8 MW thermal energy and all the engineering calculations were carried out to dimension the furnace to provide this amount of heat. Shallow bed concept was used for complete burning of the biomass particles which contained volatiles up to 75% by weight. The sand bed was used as a flame stabilizer for the combustion of volatiles. The combustion of volatiles in the freeboard was mainly controlled by mixing ashes and other impurities. The combustion temperature had to be maintained in the range 700--800{degrees}C to achieve combustion efficiencies of 85% or more. The combustion efficiency (1) did not increase substantially above 90% of excess air although levels of up to 120% were used during combustion and (2) was found to increase through air staging in the order of 20 to 25%, by simply adding 45 to 55% of the air required to the freeboard zone. No SO{sub 2} was observed in flue gases when burning only biomass but there was some NO{sub x} formed and the level of conversion of fuel-N to NO{sub x} was found to be about 25--30%.

75 FR 40760 - Approval and Promulgation of Air Quality Implementation Plans; Illinois; Volatile Organic...

Science.gov (United States)

2010-07-14

... Implementation Plan for Abbott Laboratories AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule... its SIP. These amendments consist of a site- specific rulemaking for certain of Abbott Laboratories' (Abbott) tunnel dryers and fluid bed dryers. This site-specific rule revision is approvable because it...

Experimental investigation of a solar dryer with natural convective heat flow

Energy Technology Data Exchange (ETDEWEB)

Gbaha, P.; Yobouet Andoh, H.; Kouassi Saraka, J. [Laboratoire d' Energies d' Energies Nouvelles et Renouvelables, Institut National Polytechnique Felix Houphoeuet-Boigny, B.P. 1526 Yamoussoukro (Ivory Coast); Kamenan Koua, B.; Toure, S. [Laboratoire d' Energie Solaire, Universite de Cocody, 22 B.P.: 582, Abidjan 22 (Ivory Coast)

2007-09-15

A direct type natural convection solar dryer is designed. It is constructed in local materials (wood, blades of glass, metals) then tested experimentally in foodstuffs drying (cassava, bananas, mango). It is about an experimental approach which consists in analyzing the behavior of the dryer. The study relates mainly kinetics and establishment of drying heat balances. The influence of significant parameters governing heat and mass transfers, such as solar incident radiation, drying air mass flow and effectiveness, is analyzed in order to evaluate its thermal performances. Experimental data can be represented by empirical correlations of the form M(t)=M{sub i}exp(-kt) for representation of drying process. The resolution of these drying equations makes-possible to predict total drying time of each product. Moreover, this drying process allows to reduce the moisture content of cassava and sweet banana approximately to 80% in 19 and 22 h, respectively to reach the safety threshold value of 13%. This value permits the conservation of these products about one year without deterioration. The determination of parameters, like ambient temperature, drying chamber temperature, drying air mass flow and incident heat fluxes, allow to predict the drying effectiveness for modeling and refining the dimensioning of the elaborate prototype. (author)

Effect of separation and drainage of condensate on dehumidification in a refrigerated dryer; Reito joshitsuki ni okeru gyoshukusui bunri/haishutsu noryoku no joshitsu seino ni oyobosu eikyo

Energy Technology Data Exchange (ETDEWEB)

Goto, H.; Ichinose, T. [SMC Corp., Tokyo (Japan); Tanzawa, Y.; Hashizume, T. [Waseda Univ., Tokyo (Japan). Science and Engineering Research Lab.

1995-11-15

The representative refrigerated dryer as the compressed air dryers is one in which air was cooled at rather low temperature by working medium of refrigerators, and the dew point was decreased with increase of pressure, and air with low relative humility called as the dried air was obtained again by heating. In this paper, for clarifying effect of separation and drainage of condensate on dehumidification in a refrigerated dryer in relation to shape of a main cooler and a precool-reheater and air temperature of each part, calculation and experimental investigation were conducted. In a refrigerated dryer, condensate happened in the precool part of a precool-reheater and a main cooler, and this would give rise to reduce of separation and drainage of condensate and increase of thermal loads of each heat exchange, and would made dehumidification low. For a fact that decrease of separation and drainage of condensate in a main cooler would bring out heat conduction with phase change in the reheating part of a precool-reheater, it has a profitable side, but it is not desirable for ability of dryers. 6 refs., 9 figs., 1 tab.

78 FR 20842 - Energy Conservation Program: Energy Conservation Standards for Residential Clothes Dryers and...

Science.gov (United States)

2013-04-08

... DeLonghi); energy and environmental advocates (American Council for an Energy Efficient Economy (ACEEE... DEPARTMENT OF ENERGY 10 CFR Part 430 [Docket Number EERE-2013-BT-STD-0020] RIN 1904-AC98 Energy Conservation Program: Energy Conservation Standards for Residential Clothes Dryers and Room Air Conditioners...

Preservation of fruits and vegetables using solar dryers. A comparative study for solar and natural drying of grapes, figs, tomatoes and onions. IV. temperature measurements, calculating the generated energy and dryer efficiency during drying

International Nuclear Information System (INIS)

Sehery, A.A.; Gallali, Y.M.; Shoshan, H.

2000-01-01

This study has taken four axis, first, design and construction of the dryer, secondly, microbial load determination, thirdly, chemical and sensory evaluation data. The results of these three parts were published earlier at the International Congress on Application of Solar and Renewable Energy, Food Science and Technology and World Renewable Energy Congress V, Cairo, Egypt, 1992, 1996 and Florence, Italy, 1998, respectively. The whole study was oriented towards comparing the solar (three modes, direct, indirect, and mixed) and natural drying. The fourth part of the study is dealing with some parameters affecting drying as temperature measurement, calculating the generated energy and the dryer efficiency during drying periods. Drying temperature is considered the most important factor in the drying operation, since the accuracy of temperature measurement gives the correct results and right indication for the approval of these scientific methods in the drying operation and the design of solar dryers. In this project, we depended on temperature measurements at different points by means of thermocouples fixed in the heat collector and the drying chamber. The average temperature outside the dryer ranged from 21-41 degree C. That of the heat collector were 40-75 degree C and those of the drying chamber were in the range of 40-73 degree C. The radiation measurements calculated depending on the results recorded by the solar center instruments from 5/8/95 - 16/10/95. The thermal energy existing from the heat collector to the drying chamber during the drying period was measured using the equation of Holland. From the investigation results, we can conclude that in all trials, solar drying was a more efficient method for drying all samples of fruits and vegetables, especially for grapes, figs and onion. Grapes dried using mixed mode from 83 % to 30 % moisture in 4 days at an average temperature of 55 degree C while natural drying reduced the moisture to 57% for the same period

Modelling and simulation of processes by smart sensing : a solar dryer for plant material

Energy Technology Data Exchange (ETDEWEB)

Correa, E.C.; Diezma, B.; Ruiz-Altisent, M. [LPF-TAGRALIA Univ. Politecnica, CENIM-CSIC, Madrid (Spain)

2010-07-01

This paper reported on a study in which as small wood dryer was modelled. Studies have shown that properly designed solar dryers may prove to be energy saving devices for drying processes. The drying rate expressed as -dX/dt=f/X (where X is DB wood moisture content), allows to identify 2 different kinetics, notably for high X values or fibre saturation point (FSP) and for X values under FSP, in which diffusion is the mechanism that governs a decreasing drying rate at this stage. The complex drying rate model developed in this study made it possible the determine the wood and convective mass transfer at the wood-air interface. Validation and application to fruit and plant drying cycles is currently underway. Three different proposed models are used in the software for a smart sensor system, which is based on Sensirion sensors for temperature and relative humidity in the air, and thermocouples for timber temperature.

Alterations in fruit and vegetable beta-carotene and vitamin C content caused by open-sun drying, visqueen-covered and polyethylene-covered solar-dryers.

Science.gov (United States)

Ndawula, J; Kabasa, J D; Byaruhanga, Y B

2004-08-01

This study investigated the effects of three drying methods (open sun drying, visqueen-covered solar dryer and polyethylene-covered solar dryer) on b-carotene and vitamin C content of edible portions of mango fruit (Mangifera indica) and cowpea leaves (Vigna unguiculata). Commercial samples were analysed for vitamin C by titrimetry and b-carotene by spectrophotometry at 450 nm. Differences in vitamin retention and loss associated with the three drying methods were assessed by analysis of variance and least significant difference (LSD) at (pdrying. Open sun drying method caused the greatest b-carotene and vitamin C loss (58% and 84% respectively), while the visqueen-covered solar dryer caused the least loss (34.5% and 71% respectively). Blanching cowpea leaves improved b-carotene and vitamin C retention by 15% and 7.5% respectively. The b-carotene and vitamin C content of fresh ripe mango fruit was 5.9 and 164.3 mg/100g DM respectively. Similar to effects on cowpea leaves, the mango micronutrient content decreased (pdrying. The open sun drying method caused the greatest b-carotene (94.2%) and vitamin C (84.5%) loss, while the visqueen-covered solar dryer caused the least (73 and 53% respectively). These results show that the three solar drying methods cause significant loss of pro-vitamin A and vitamin C in dried fruits and vegetables. However, open sun drying causes the most loss and the visqueen-covered solar dryer the least, making the later a probable better drying technology for fruit and vegetable preservation. The drying technologies should be improved to enhance vitamin retention.

Survey on solar dryers for drying of food and wood in Ghana

Energy Technology Data Exchange (ETDEWEB)

Oestergaard Jensen, S.; Correll Frank, F. [Danish Technological Inst., Taastrup (Denmark); Floejgaard Kristensen, E. [Danish Inst. of Agricultural Sciences, Tjele (Denmark)

1999-11-01

The survey was conducted as a part of the project 'Test and Research Project into the Drying of Food and Wood Products with Solar Heat'. The aim of the survey was to investigate the need for drying of food and wood in Ghana and the already existing experience on solar drying in order to form a basis for the initial decisions within the project concerning the location of three demonstration solar dryers for crops, fish and wood, which species to dry and the type of solar dryers. The project deals with transfer of knowledge in the field of drying of crops and wood and solar air heating systems from Denmark to Ghana. The aim of the survey was, therefore, also to give the Danish experts an impression of the conditions in Ghana in order to facilitate an appropriate design of the solar dryers. Three of the four Danish partners participated in the survey. The fourth Danish partner - the manufacturer of solar heating systems Aidt Miljoe - are already familiar with the conditions in Ghana due to an earlier project in Ghana. The survey was planed by the Energy Commission of Ghana, the Ghanaian partner and consultants: DENG, University of Science and Technology, Kumasi and Econkoad. The time schedules for the survey - one for crops/fish and one for wood - are found in Annex A. The schedules were very well prepared and the sites to visit were well chosen. The visits gave the Danish experts a good overview of the situation in Ghana in the field of post harvesting of crops, handling of fish, drying and manufacturing of wood and existing experience on solar drying. The schedules included a large variety of different information and impressions e.g. ranging from large sawmill to small carpenters and workshops. Despite tight schedules the consultants managed to stick very close to the time schedules shown in Annex A. (au)

"To sleep, perchance to tweet": in-bed electronic social media use and its associations with insomnia, daytime sleepiness, mood, and sleep duration in adults.

Science.gov (United States)

Bhat, Sushanth; Pinto-Zipp, Genevieve; Upadhyay, Hinesh; Polos, Peter G

2018-04-01

The use of mobile device-based electronic social media (ESM) in bed is rapidly becoming commonplace, with potentially adverse impacts on sleep and daytime functioning. The purpose of this study was to determine the extent to which in-bed ESM use is associated with insomnia, daytime sleepiness, mood, and sleep duration in adults. This was a cross-sectional observational study conducted among 855 hospital employees and university students (mean age, 43.6years; 85% female) via an online questionnaire. Nearly 70% of participants indulged in in-bed ESM use, with nearly 15% spending an hour or more a night doing so. The degree of in-bed ESM use did not vary by gender, but higher levels of in-bed ESM use were seen in younger and middle-aged than elderly participants. Compared with participants with no in-bed ESM use and controlling for age, gender, and ethnicity, participants with high in-bed ESM use were more likely to have insomnia, anxiety, and short sleep duration on weeknights, but not depression or daytime sleepiness; low in-bed ESM use only increased the likelihood of short sleep duration on weeknights. In-bed ESM use by a bed partner did not have an adverse association with sleep or mood. In-bed ESM use is associated with sleep and mood dysfunction in adults. These findings are of relevance to clinicians, therapists, and the public at large, as they suggest that limitation of in-bed ESM use is a potential interventional strategy in the overall management of sleep hygiene and mental health. Copyright © 2017 National Sleep Foundation. Published by Elsevier Inc. All rights reserved.

Simulation of exhaust gas heat recovery from a spray dryer

International Nuclear Information System (INIS)

Golman, Boris; Julklang, Wittaya

2014-01-01

This study explored various alternatives in improving the energy utilization of spray drying process through the exhaust gas heat recovery. Extensible and user-friendly simulation code was written in Visual Basic for Applications within Microsoft Excel for this purpose. The effects of process parameters were analyzed on the energy efficiency and energy saving in the industrial-scale spray drying system with exhaust gas heat recovery in an air-to-air heat exchanger and in the system with partial recirculation of exhaust air. The spray dryer is equipped with an indirect heater for heating the drying air. The maximum gains of 16% in energy efficiency and 50% in energy saving were obtained for spray drying system equipped with heat exchanger for exhaust air heat recovery. In addition, 34% in energy efficiency and 61% in energy saving for system with recirculation of exhaust air in the present range of process parameters. The high energy efficiency was obtained during drying of large amount of dilute slurry. The energy saving was increased using the large amount of hot drying air. - Highlights: • We model industrial-scale spray drying process with the exhaust gas heat recovery. • We develop an Excel VBA computer program to simulate spray dryer with heat recovery. • We examine effects of process parameters on energy efficiency and energy saving. • High energy efficiency is obtained during drying of large amount of dilute slurry. • Energy saving is increased using the large amount of hot drying air

The effect of fan speed control system on the inlet air temperature uniformity in a solar dryer

Directory of Open Access Journals (Sweden)

S. F Mousavi

2015-09-01

Full Text Available Introduction: Drying process of agricultural products, fruits and vegetables are highly energy demanding and hence are the most expensive postharvest operation. Nowadays, the application of control systems in different area of science and engineering plays a key role and is considered as the important and inseparable parts of any industrial process. The review of literature indicates that enormous efforts have been donefor the intelligent control of solar driers and in this regard some simulation models are used through computer programming. However, because of the effect of air velocity on the inlet air temperature in dryers, efforts have been made to control the fan speed based ont he temperature of the absorber plate in this study, and the behavior of this system was compared with an ordinary dryer without such a control system. Materials and methods: In this study, acabinet type solar dryer with forced convection and 5kg capacity of fresh herbs was used. The dryer was equipped with a fan in the outlet chamber (the chimney for creating air flow through the dryer. For the purpose of research methods and automatic control of fan speed and for adjusting the temperature of the drying inlet air, a control system consisting of a series of temperature and humidity sensors and a microcontroller was designed. To evaluatethe effect of the system with fan speed control on the uniformity of air temperature in the drying chamber and hence the trend of drying process in the solar dryer, the dryer has been used with two different modes: with and without the control of fan speed, each in twodays (to minimize the errors of almost the same ambient temperature. The ambient air temperature during the four days of experiments was obtained from the regional Meteorological Office. Some fresh mint plants (Mentha longifolia directly harvested from the farm in the morning of the experiment days were used as the drying materials. Each experimental run continued for 9

Analysis of Energy Consumption of "Compression Heat" Pressure Heat Dryer%“压缩热”干燥机能耗分析

Institute of Scientific and Technical Information of China (English)

李申

2015-01-01

作为典型的热质交换设备，吸附干燥器再生能量是被吸水量锁定的。总耗能受到吸附剂本身物理性质的制约，可用“质量守恒”与“能量守恒”两大定律来解释其能耗过程。各类吸附干燥器能耗量都要通过“能量衡算”来确定。“压缩热”干燥器与其他一切加热干燥器一样采取了“长周期”工作循环制，解吸环节无效热损很大。无热再生干燥器则采用了“短周期”工作制，为实际耗气量减少留有了较大的空间。%As the typical heat and mass transfer equipment, the energy of regenerative desiccant dryers is limited by water absorption. The total energy consumption is restricted by the physical properties of the adsorbent, which can be explained through two laws of conservation of mass and energy conservation. The energy consumption in each absorption dryers should be determined by“energy balance”.“Compression heat”dryer adopts“long-period”working cycle system as other heating dryers, in which invalid heat losses are great in desorption process. However, regenerated dryer without heat adopts“short-period”working cycle system, which provides greater space for actual gas consumption reduction.

Intermittent Coffee Drying in Deep Bed with Pulsed Airflow Secado de Café en Lecho Fijo con Intermitencia Térmica y Flujo de Aire Pulsado

Directory of Open Access Journals (Sweden)

Héctor José Ciro Velásquez

2011-12-01

Full Text Available A dryer in deep bed without airflow reversal was adapted to work simultaneously with thermal intermittence and pulsed airflow in the drying of parchment coffee bean. The dryer was operated by cycles of thermal intermittence for a heating temperature of 55 °C and cooling of 40 and 25 °C. The results showed that the increase of temperature in the cycle of cooling tends to increase the water removal and that the increase of the number of air pulses without reversal of the direction of air flow causes an excessive moisture gradient within the batch. Moreover, the specific energy requirement of the dryer was from 15 to 25 MJ/kg, showing the best thermal performance for the condition in which the dryer was operate without pulsed airflow.Un secador de lecho fijo fue adaptado para trabajar de forma simultánea con intermitencia térmica y flujo de aire pulsado sin inversión de flujo de aire, en el secado de granos de café. El secador fue operado con ciclos de intermitencia térmica para una temperatura de calentamiento de 55 °C y enfriamiento de 40 y 25 °C. Los resultados mostraron que el aumento de temperatura en el ciclo de enfriamiento, tiende a incrementar la remoción de agua y que el aumento del número de pulsos de aire sin inversión del flujo de dirección del aire, ocasiona un secado deficiente debido al excesivo gradiente de humedad ocasionado en la capa de producto. Adicionalmente, se encontró que el consumo de energía específica del secador varió entre 15 y 25 MJ/kg de agua evaporada, siendo el mejor rendimiento termo energético para la condición en la cual el secador fue operado sin flujo de aire pulsado.

Modelling the drying kinetics of green peas in a solar dryer and under open sun

Energy Technology Data Exchange (ETDEWEB)

Sunil [Department of Mechanical Engineering, BRCM CET Bahal, Haryana–127028 (India); Varun [Department of Mechanical Engineering, NIT Hamirpur, (H.P.)–177005 (India); Sharma, Naveen [Department of Mechanical and Industrial Engineering, IITR, (U.K.)–247667 (India)

2013-07-01

The drying kinetics of green peas was investigated in an indirect solar dryer and under open sun. The entire drying process took place exclusively in falling rate period. The constant rate period was absent from the drying curves. The rehydration capacity was also determined for peas dried in solar dryer and under open sun. The rehydration capacity of solar dried peas was found higher than open sun dried peas. The drying data obtained from experiments were fitted to eight different mathematical models. The performance of these models was examined by comparing the coefficient of correlation (R2), sum of squares error (SSE), mean squared error (MSE) and root mean square error (RMSE) between observed and predicted values of moisture ratios. Among these models, the thin layer drying model developed by Page showed good agreement with the data obtained from experiments for bottom tray. The Midilli et al. model has shown better fit to the experimental data for top tray and open sun than other models.

Analysis of heat recovery from a spray dryer by recirculation of exhaust air

International Nuclear Information System (INIS)

Golman, Boris; Julklang, Wittaya

2014-01-01

Highlights: • We study a spray dryer with heat recovery by partial recirculation of exhaust air. • We examine effects of process parameters on energy efficiency and energy savings. • Decreasing drying air temperature and flow rate will increase energy efficiency. • Increasing recirculation ratio and slurry feed rate will increase energy efficiency. - Abstract: Model simulations were employed to investigate the influences of process parameters on the energy recovery in spray drying process that partially recycle the exhaust drying gas. The energy efficiency and energy saving were studied for various values of recirculation ratios with respect to the temperature and flow rate of the drying air, slurry feed rate and concentration of slurry in spray drying of advanced ceramic materials. As a result, significant gains in energy efficiency and energy saving were obtained for a spray drying system with high recirculation ratio of exhaust air. The high slurry feed rate and the low slurry concentration, inlet drying air temperature and drying air flow rate enhanced the energy efficiency of spray drying system. However, the high energy saving was obtained in spray dryers operating at low slurry feed rate and high slurry concentration

(2) TAIWO ET AL PAPER ON CASSAVA CHIPS

African Journals Online (AJOL)

Adeyinka Odunsi

and in beds of varying thickness. It would be impractical from both the standpoint of manufacture and customer use, to design and build many different models of crop dryers. (Dorn, 2009). To accomplish the above stated objective, a prototype cabinet dryer developed in a previous research effort was equipped with a ...

A Grey-Box Model for Spray Drying Plants

DEFF Research Database (Denmark)

Petersen, Lars Norbert; Poulsen, Niels Kjølstad; Niemann, Hans Henrik

2013-01-01

Multi-stage spray drying is an important and widely used unit operation in the production of food powders. In this paper we develop and present a dynamic model of the complete drying process in a multi-stage spray dryer. The dryer is divided into three stages: The spray stage and two fluid bed...

Real-time process monitoring in a semi-continuous fluid-bed dryer - microwave resonance technology versus near-infrared spectroscopy.

Science.gov (United States)

Peters, Johanna; Teske, Andreas; Taute, Wolfgang; Döscher, Claas; Höft, Michael; Knöchel, Reinhard; Breitkreutz, Jörg

2018-02-15

The trend towards continuous manufacturing in the pharmaceutical industry is associated with an increasing demand for advanced control strategies. It is a mandatory requirement to obtain reliable real-time information on critical quality attributes (CQA) during every process step as the decision on diversion of material needs to be performed fast and automatically. Where possible, production equipment should provide redundant systems for in-process control (IPC) measurements to ensure continuous process monitoring even if one of the systems is not available. In this paper, two methods for real-time monitoring of granule moisture in a semi-continuous fluid-bed drying unit are compared. While near-infrared (NIR) spectroscopy has already proven to be a suitable process analytical technology (PAT) tool for moisture measurements in fluid-bed applications, microwave resonance technology (MRT) showed difficulties to monitor moistures above 8% until recently. The results indicate, that the newly developed MRT sensor operating at four resonances is capable to compete with NIR spectroscopy. While NIR spectra were preprocessed by mean centering and first derivative before application of partial least squares (PLS) regression to build predictive models (RMSEP = 0.20%), microwave moisture values of two resonances sufficed to build a statistically close multiple linear regression (MLR) model (RMSEP = 0.07%) for moisture prediction. Thereby, it could be verified that moisture monitoring by MRT sensor systems could be a valuable alternative to NIR spectroscopy or could be used as a redundant system providing great ease of application. Copyright © 2017 Elsevier B.V. All rights reserved.

Influence of the process control on the thermal energy requirement of convection dryers in the brick industry; Einfluss der Prozessfuehrung auf den thermischen Energiebedarf von Konvektionstrocknern in der Ziegelindustrie

Energy Technology Data Exchange (ETDEWEB)

Tretau, Anne

2008-06-10

Brick manufacturing demands high amount of energy. The energy flow analysis inside the brick factory shows that the convective drying of green bricks consumes more than half of the total thermal energy required for brick manufacturing. Therefore this paper deals with the theoretical analysis and investigation for the energy requirement of green bricks. For this, a physical-based model has been developed, which describes the dependence of drying-kinetics as well as the energy-requirement interims of the process parameter like mass of the supply air. It turns out that the specific energy requirement substantially depends on temperature and humidity of the ambience air and also supply air mass flow and its temperature. Due to the continuous temperature rise of the green bricks during the second drying section the specific energy requirement increases significantly with the progressive motion of the drying in a chamber dryer. This is due to the fact that the green brick as well as the air conditioning distance more and more from the cooling limit. Just a low part of the dryer exhaust air is saturated. The exhaust air is continuously sucked out and the green bricks are pulled inside the dryer. So the exhaust air has a relatively higher water saturation. On general, continuous dryers have a lower energy requirement than chamber dryer. For the both types of dryers, the mathematical model shows that the increasing of the supply air temperature combined with a commensurate subsidence of supply air mass flow, results in a reduction of drying energy requirement. The change of other essential parameters of drying like green brick thickness, and density as well as the moisture diffusion coefficient, and the vapour diffusity which are only important in the second drying section are of comparatively negligible effect. The developed mathematical model is successfully implemented for the energy investigation in the industrial dryers. The increase in supply air temperature results

The progress of test and study for steam dryer in vertical steam generator

International Nuclear Information System (INIS)

Ding Xunshen

1993-01-01

Constructions, tests and test results are reviewed for three types of steam generator dryer that are concentric vertical corrugated separator, centrifugal conic separator and chevron separator. The last type is considered as the best one in comparison, which has been applied to Qinshan 300 MW steam generator. A number of pertinent remarks to draining scheme, hydraulic loss reduction, and conduct of test are given based on experiences

Temperature and energy consumption for clothing dryer; Temperatura e consumo de energia em secadora de vestuario

Energy Technology Data Exchange (ETDEWEB)

Ribeiro, Jefferson Almeida; Magalhaes Filho, Paulo [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia. Dept. de Energia]. E-mail: pfilho@feg.unesp.br

2000-07-01

The cloth dehumidification is done by hot air circulation through it in dryers. The air circulation is done by a fan, run by an electrical motor, and the air temperature raise, which goes through the cloths aiming their moisture dragging, is gotten by the heat dissipation from electrical resistance. This work shows the results of an experimental modeling, examining the behavior of several kinds of cloth in a vertical suspense-type dryer, such as: polyester, cotton-spandex, flannel, blue-jeans and viscose rayon. It was analyzed the behavior of the moisture content in these cloths related to controlled-temperature-air flows, determining the needed heat to reach the required drying standards. The drying device fans were tested for the determination of their flow rate and energy consumption, establishing a flow rate versus consumption relationship. Comparative results among the various kinds of cloths are presented. (author)

Experimental investigation on energy and exergy analysis of coriander (Coriadrum sativum L.) leaves drying in natural convection solar dryer

International Nuclear Information System (INIS)

Panwar, N.L.

2014-01-01

This study deals with thin layer drying characteristics of Coriandrum sativum L. leaves in a natural convection solar dryer. The Coriandrum sativum L. leaves were dried from a moisture content of 88% (w.b.) to 4.5% (w.b.) in 7.5 hours. The obtained drying data were fitted to eight different drying kinetics models. Of these, the model suggested by Midilli et al. [20] had the best fit with the drying behavior of Coriandrum sativum L. leaves. In addition, the thermodynamic behaviour of a solar dryer was evaluated. The energy efficiency during the study varied from 7.81 to 37.93%. The exergy efficiency of the drying process ranged between 55.35 and 79.39%. (author)

Design of mixed-mode natural convection solar crop dryers: Application of principles and rules of thumb

Energy Technology Data Exchange (ETDEWEB)

Forson, F.K.; Akuffo, F.O. [Department of Mechanical Engineering, Kwame Nkrumah University of Science and Technology, Kumasi (Ghana); Nazha, M.A.A.; Rajakaruna, H. [Department of Mechanical Engineering, De Montfort University, Queens Building, Leicester LE1 9BH (United Kingdom)

2007-11-15

A mixed-mode natural convection solar crop dryer (MNCSCD) designed and used for drying cassava and other crops in an enclosed structure is presented. A prototype of the dryer was constructed to specification and used in experimental drying tests. This paper outlines the systematic combination of the application of basic design concepts, and rules of thumb resulting from numerous and several years of experimental studies used and presents the results of calculations of the design parameters. A batch of cassava 160 kg by mass, having an initial moisture content of 67% wet basis from which 100 kg of water is required to be removed to have it dried to a desired moisture content of 17% wet basis, is used as the drying load in designing the dryer. A drying time of 30-36 h is assumed for the anticipated test location (Kumasi; 6.7 N,1.6 W) with an expected average solar irradiance of 400 W/m{sup 2} and ambient conditions of 25 C and 77.8% relative humidity. A minimum of 42.4 m{sup 2} of solar collection area, according to the design, is required for an expected drying efficiency of 12.5%. Under average ambient conditions of 28.2 C and 72.1% relative humidity with solar irradiance of 340.4 W/m{sup 2}, a drying time of 35.5 h was realised and the drying efficiency was evaluated as 12.3% when tested under full designed load signifying that the design procedure proposed is sufficiently reliable. (author)

Operational Augmentation of Forced Circulation Type Solar Dryer System Using CFD Analysis

OpenAIRE

Atul Patel; Gaurav Patel

2014-01-01

Solar drying is basically heat and mass transfer process in which the liquid water from the surface and the vapour removed by draft. The efficiency of a solar drying system is affected by the properties of drying materials.e.g. size, shape and geometry as well as ambient conditions. In this research article, the authors have done the CFD analysis of a Forced Circulation type Solar Dryer used conventionally for dehydrating vegetables and fruits. Using CFD analysis, the limiting...

Determination of viscosity in recirculating fluidized bed using radioactive tracer

International Nuclear Information System (INIS)

Silva, G.G. da.

1986-01-01

The use of radioactive tracer for measuring viscosity is proposed. The methodology relates the terminal velocity of a radioactive sphere in interior of fluid with the viscosity, which can be a fluidized bed or total flow of solids. The arrangement is composed by two γ detectors placed externally and along the bed. Both detectors are coupled by amplifier to electronic clock. The drop time of sphere between two detectors is measured. The bed viscosity two detectors is measured. The bed viscosity is calculated from mathematical correlations of terminal velocity of the sphere. (M.C.K.)

Theory and measurements of electrophoretic effects in monolith, fixed-bed, and fluidized-bed plasma reactors

International Nuclear Information System (INIS)

Morin, T.J.

1989-01-01

Pressure gradients and secondary flow fields generated by the passage of electrical current in a d.c. gas discharge or gas laser are topics of longstanding interest in the gaseous electronics literature. These hydrodynamic effects of space charge fields and charged particle density gradients have been principally exploited in the development of gas separation and purification processes. In recent characterization studies of fixed-bed and fluidized-bed plasma reactors several anomalous flow features have been observed. These reactors involve the contacting of a high-frequency, resonantly-sustained, disperse gas discharge with granular solids in a fixed or fluidized bed. Anomalies in the measured pressure drops and fluidization velocities have motivated the development of an appropriate theoretical approach to, and some additional experimental investigations of electrophoretic effects in disperse gas discharges. In this paper, a theory which includes the effects of space charge and diffusion is used to estimate the electric field and charged particle density profiles. These profiles are then used to calculate velocity fields and gas flow rates for monolith, fixed-bed, and fluidized-bed reactors. These results are used to rationalize measurements of gas flow rates and axial pressure gradients in high-frequency disperse gas discharges with and without an additional d.c. axial electric field

Tailoring the thermal conductivity of the powder bed in Electron Beam Melting (EBM) Additive Manufacturing.

Science.gov (United States)

Smith, C J; Tammas-Williams, S; Hernandez-Nava, E; Todd, I

2017-09-05

Metallic powder bed additive manufacturing is capable of producing complex, functional parts by repeatedly depositing thin layers of powder particles atop of each other whilst selectively melting the corresponding part cross-section into each layer. A weakness with this approach arises when melting overhanging features, which have no prior melted material directly beneath them. This is due to the lower thermal conductivity of the powder relative to solid material, which as a result leads to an accumulation of heat and thus distortion. The Electron Beam Melting (EBM) process alleviates this to some extent as the powder must first be sintered (by the beam itself) before it is melted, which results in the added benefit of increasing the thermal conductivity. This study thus sought to investigate to what extent the thermal conductivity of local regions in a titanium Ti-6Al-4V powder bed could be varied by imparting more energy from the beam. Thermal diffusivity and density measurements were taken of the resulting sintered samples, which ranged from being loosely to very well consolidated. It was found that the calculated thermal conductivity at two temperatures, 40 and 730 °C, was more than doubled over the range of input energies explored.

Behavior of a portable solar dryer for pineapple fiber Comportamento de um secador solar para fibras de abacaxi

Directory of Open Access Journals (Sweden)

Róger Moya

2012-12-01

Full Text Available In Costa Rica, there has been a growing interest to use pineapple fiber from plant, for which current processes need to be improved or new processes need to be developed, with emphasis on drying methods. This work presents the design and evaluation of the behavior of a prototype portable solar dryer in four sites of Costa Rica. The design describes the main parts of the dryer, as well as how they were constructed. The behavior was evaluated according to temperature and relative humidity inside e outside the chamber, and the influence of direct and indirect solar radiation. In order to achieve improved dryer efficiency, a dehumidifier was used to control relative humidity, and a heating system was implemented during the hours of low temperature, low solar radiation and high relative humidity. Based on drying time, final moisture content of fibers of pineapple leaves from plant, and the varying hours when fibers were put to dry, the evaluation of the dryer revealed that the best fiber-drying interval is from 6h00 to 14h00, and after that, it is convenient to inject hot air and use a dehumidifier in the dryer in order to increase its efficiency.Na Costa Rica, o interesse pelo uso da fibra proveniente da folha de abacaxizeiro. Tem almentado e essa atividade precisa de melhoramento ou implementação de novos processos para alcançar maior eficiência, principalmente na secagem da fibra. O presente trabalho apresenta o design e comportamento de uma protótipo portátil de secadora solar em 4 sites geográficos da Costa Rica. Estão descritas as principais partes do secador, bem como a metodologia de construção. O comportamento foi avaliado de acordo com a temperatura e umidade relativa interna e externa da câmara e a influencia da radiação direta e indireta. Com a finalidade de melhorar a eficiência da secadora, foi usado um desumidificador para controlar a umidade relativa e ainda um sistema de aquecimento durante as horas de baixa temperatura

Evaluation of a fruit solar dryer; Avaliacao de um secador solar de frutas

Energy Technology Data Exchange (ETDEWEB)

Berthier, L.J.; Bittencourt, J.; Queiroz, M.R.

2000-07-01

A study of the Nanica banana drying was carried out in a solar dryer with six trays operating with direct exposure of the product to the solar radiation and internal convection. The solar drying was performed College of Agricultural Engineering of the UNICAMP, Campinas, S.Paulo state, Brazil. The study aimed a 20 to 25 per cent final humidity of the dry product, result obtained in the different trays during a maximum drying period of 147 hours (6 days), in a batch system. During the drying period, the average temperature of the environment air at daylight was of 26 degree Celsius with a maximum of 32 degree Celsius, and 18 degrees Celsius during nocturnal period, with a minimum of 12,6 degree Celsius. In the inward of the dryer reached average values near to 50 degree Celsius, measured at noon. The 29,540 kg initial net weight of peeled banana was reduced to yield of 10,815 kg after the drying process, obtaining an income of 36,61 percent of the total production. With the values of the product weight loss, the curves of the drying in each tray had been built, observing that, in the upper trays reached the desired humidity in a lesser period.

Aging and service wear of air compressors and dryers in nuclear power plants

International Nuclear Information System (INIS)

Moyers, J.C.

1989-01-01

Compressed air systems and their associated compressors and dryers as incorporated in LWR power plants usually are not classified as safety related systems and components because their continued operation is not required to bring the plant to a safe shutdown condition. However, control air is a vital requirement for maintaining stable plant operation and its loss often results in a reactor trip and, on occasion, the actuation of engineered safety feature systems. Concerns caused by repeated instances of failures in air systems resulted in the high-priority ranking of Generic Issue No. 43, ''Reliability of Air Systems'' by the NRC. In support of the Nuclear Plant Aging Research (NPAR) Program, the Oak Ridge National Laboratory is carrying out a Phase I aging assessment of air compressors and dryers used in LWR power plants. The objectives of this study include: (1) determination of the types and ratings of equipment utilized in typical plants; (2) identification of aging and service wear stressors imposed on the machines; (3) evaluation of operating experience with the machines; (4) comparison of user and manufacturer-recommended inspection, surveillance, and monitoring (ISM) methods; and (5) the identification of any improved ISM methods that might lead to longer, more reliable, service. 2 refs

Performance of A Horizontal Cylinder Type Rotary Dryer for Drying Process ofOrganic Compost from Solid Waste Cocoa Pod

Directory of Open Access Journals (Sweden)

Sukrisno Widyotomo

2008-07-01

Full Text Available Cocoa pod husk is the bigest component of cocoa pod, about 70% of total ht of mature pod, and to potentially used as organic compost source. Poten tial solid waste of cocoa pod husk from a cocoa processing centre is about 15— 22 m3/ha/year. A cocoa plantation needs about 20—30 ton/ha/year of organic matters. One of important steps in compos processing technology of cocoa pod solid waste is drying process. Organic compost with 20% moisture content is more easy in handling, application, storage and distribution. Indonesian Coffee and Cocoa Research Institute has designed and tested a horizontal cylinder type rotary dryer for drying process of organic compos from solid waste cocoa pod with kerosene burner as energy sources. The objective of this research is to study performance of a horizontal cylinder type rotary dryer using kerosene burner as energy source for drying process of organic compost from solid waste cocoa pod. The material used was solid waste cocoa pod with 70—75% moisture content (wet basis, 70% size particle larger than 4.76 mm, and 30% size particle less than 4.76 mm, 690—695 kg/m3 bulk density. Drying process temperatures treatment were 60OC, 80OC, and 100OC, and cylinder rotary speed treatments were 7 rpm, 10 rpm, dan 16 rpm. The results showed that dryer had capacity about 102—150 kg/h depend on drying temperature and cylinder rotary speed. Optimum operation condition at 100OC drying temperature, and 10 rpm cylinder rotary speed with drying time to reach final moisture content of 20% was 1,6 h, capacity 136,14 kg/ h, bulk density 410 kg/m3, porocity 45,15%, kerosene consumption as energy source was 2,57 l/h, and drying efficiency 68,34%. Key words : cocoa, drying, rotary dryer, compost, waste

75 FR 37593 - Energy Conservation Program for Consumer Products: Test Procedures for Clothes Dryers and Room...

Science.gov (United States)

2010-06-29

... docket number EERE-2008-BT-TP-0010 and/or RIN 1904-AC02 in the subject line of the message. 3. Mail: Ms... DOE clothes washer test procedure), which is assumed to proportionally impact dryer load sizes. DOE... noted that IEC Standard 62087 specifies methods of measuring the power consumption of TV receivers...

Using multiple bed load measurements: Toward the identification of bed dilation and contraction in gravel-bed rivers

Science.gov (United States)

Marquis, G. A.; Roy, A. G.

2012-02-01

This study examines bed load transport processes in a small gravel-bed river (Béard Creek, Québec) using three complementary methods: bed elevation changes between successive floods, bed activity surveys using tags inserted into the bed, and bed load transport rates from bed load traps. The analysis of 20 flood events capable of mobilizing bed material led to the identification of divergent results among the methods. In particular, bed elevation changes were not consistent with the bed activity surveys. In many cases, bed elevation changes were significant (1 to 2 times the D50) even if the bed surface had not been activated during the flood, leading to the identification of processes of bed dilation and contraction that occurred over 10% to 40% of the bed surface. These dynamics of the river bed prevent accurate derivation of bed load transport rates from topographic changes, especially for low magnitude floods. This paper discusses the mechanisms that could explain the dilation and contraction of particles within the bed and their implications in fluvial dynamics. Bed contraction seems to be the result of the winnowing of the fine sediments under very low gravel transport. Bed dilation seems to occur on patches of the bed at the threshold of motion where various processes such as fine sediment infiltration lead to the maintenance of a larger sediment framework volume. Both processes are also influenced by flood history and the initial local bed state and in turn may have a significant impact on sediment transport and morphological changes in gravel-bed rivers.

Bed Bug Infestations and Control Practices in China: Implications for Fighting the Global Bed Bug Resurgence

Directory of Open Access Journals (Sweden)

Changlu Wang

2011-04-01

Full Text Available The bed bug resurgence in North America, Europe, and Australia has elicited interest in investigating the causes of the widespread and increasing infestations and in developing more effective control strategies. In order to extend global perspectives on bed bug management, we reviewed bed bug literature in China by searching five Chinese language electronic databases. We also conducted telephone interviews of 68 pest control firms in two cities during March 2011. In addition, we conducted telephone interviews to 68 pest control companies within two cities in March 2011. Two species of bed bugs (Cimex lectularius L. and Cimex hemipterus (F. are known to occur in China. These were common urban pests before the early1980s. Nationwide “Four-Pest Elimination” campaigns (bed bugs being one of the targeted pests were implemented in China from 1960 to the early 1980s. These campaigns succeeded in the elimination of bed bug infestations in most communities. Commonly used bed bug control methods included applications of hot water, sealing of bed bug harborages, physical removal, and applications of residual insecticides (mainly organophosphate sprays or dusts. Although international and domestic travel has increased rapidly in China over the past decade (2000–2010, there have only been sporadic new infestations reported in recent years. During 1999–2009, all documented bed bug infestations were found in group living facilities (military dormitories, worker dormitories, and prisons, hotels, or trains. One city (Shenzhen city near Hong Kong experienced significantly higher number of bed bug infestations. This city is characterized by a high concentration of migratory factory workers. Current bed bug control practices include educating residents, washing, reducing clutter, putting items under the hot sun in summer, and applying insecticides (pyrethroids or organophosphates. There have not been any studies or reports on bed bug insecticide

Dry reforming of methane with CO2 on an electron-activated iron catalytic bed.

Science.gov (United States)

Labrecque, Raynald; Lavoie, Jean-Michel

2011-12-01

A preliminary experimental investigation of dry reforming of methane with carbon dioxide, that has been performed on an iron bed activated with an electric current is reported. Operating conditions for the reaction included temperature ranging from 700 to 800° C and pressure close to 1 atm. The reaction, involving an excess of pure methane and carbon dioxide, was performed with and without addition of water vapour, provided by hot water saturation of the gaseous feed. According to syngas compositions, the electron flow has a dramatic effect on the conversion of both methane and carbon dioxide. It was shown also that hot water saturation of the CO(2) and CH(4) mixture allowed very good conversion, giving a syngas with a composition very close to what was expected from equilibrium calculations. Copyright © 2011 Elsevier Ltd. All rights reserved.

The Instituto Nacional de Pesquisas da Amazonia-INPA solar dryer: an economical alternative for wood drying; O secador solar do INPA: uma alternativa economica para secar madeira

Energy Technology Data Exchange (ETDEWEB)

Moraes-Duzat, Rejane; Barbosa, Ana Paula; Vetter, Roland [Instituto Nacional de Pesquisas da Amazonia (INPA), Manaus, AM (Brazil)]. E-mail: duzat@inpa.gov.br; apaula@inpa.gov.br

2000-07-01

As an alternative to the expensive and high energy consuming conventional dryers available at the market, INPA developed a solar wood dryer technically adequate to the climatic conditions of the Amazon region, and economically suitable to an industrial segment that could not afford large investments to dry wood. The dryer has received great acceptance by the industry due to its low cost and good operating efficiency. The prototype was dimensioned with a capacity of 5 to 8 m{sup 3} of sawn wood, which is sufficient for the needs of small sawmills or furniture shops. A total of 20 units have been installed in Brazil and other countries. Research work is underway to improve the performance of the original model, and some modifications are conducted to adapt it to dry other natural products as seeds, nuts, fruits, and herbs. (author)

Drying of mint leaves in a solar dryer and under open sun: Modelling, performance analyses

International Nuclear Information System (INIS)

Akpinar, E. Kavak

2010-01-01

In this study was investigated the thin-layer drying characteristics in solar dryer with forced convection and under open sun with natural convection of mint leaves, and, performed energy analysis and exergy analysis of solar drying process of mint leaves. An indirect forced convection solar dryer consisting of a solar air collector and drying cabinet was used in the experiments. The drying data were fitted to ten the different mathematical models. Among the models, Wang and Singh model for the forced solar drying and the natural sun drying were found to best explain thin-layer drying behaviour of mint leaves. Using the first law of thermodynamics, the energy analysis throughout solar drying process was estimated. However, exergy analysis during solar drying process was determined by applying the second law of thermodynamics. Energy utilization ratio (EUR) values of drying cabinet varied in the ranges between 7.826% and 46.285%. The values of exergetic efficiency were found to be in the range of 34.760-87.717%. The values of improvement potential varied between 0 and 0.017 kJ s -1 . Energy utilization ratio and improvement potential decreased with increasing drying time and ambient temperature while exergetic efficiency increased.

Energy cost of seed drying

Directory of Open Access Journals (Sweden)

Weerachet Jittanit

2017-11-01

Full Text Available In this work, the energy costs of drying corn, rice and wheat seeds between 3 drying options were compared. They consisted of 1 two-stage drying by using fluidised bed dryer (FBD in the 1st stage and in-store dryer (ISD in the 2nd stage, 2 single-stage drying by fixed bed dryer (FXD and 3 two-stage drying by using FXD in the 1st  stage and ISD in the 2nd  stage. The drying conditions selected for comparison were proved to be safe for seed viability by the previous studies. The results showed that the drying options 2 and 3 consumed less energy than option 1. However, the benefits from lower energy cost must be weighed against some advantages of using FBD. Furthermore, it appeared that running the burners of FXD and ISD for warming up the ambient air during humid weather condition could shorten drying time significantly with a little higher energy cost.

Modeling 3D conjugate heat and mass transfer for turbulent air drying of Chilean papaya in a direct contact dryer

Science.gov (United States)

Lemus-Mondaca, Roberto A.; Vega-Gálvez, Antonio; Zambra, Carlos E.; Moraga, Nelson O.

2017-01-01

A 3D model considering heat and mass transfer for food dehydration inside a direct contact dryer is studied. The k- ɛ model is used to describe turbulent air flow. The samples thermophysical properties as density, specific heat, and thermal conductivity are assumed to vary non-linearly with temperature. FVM, SIMPLE algorithm based on a FORTRAN code are used. Results unsteady velocity, temperature, moisture, kinetic energy and dissipation rate for the air flow are presented, whilst temperature and moisture values for the food also are presented. The validation procedure includes a comparison with experimental and numerical temperature and moisture content results obtained from experimental data, reaching a deviation 7-10 %. In addition, this turbulent k- ɛ model provided a better understanding of the transport phenomenon inside the dryer and sample.

Drying characteristics of osmotically pretreated cranberries : Energy and quality aspects

Energy Technology Data Exchange (ETDEWEB)

Grabowski, S.; Marcotte, M. [Agriculture and Agri-Food Canada, St. Hyacinthe, PQ (Canada). Food Research and Development Centre; Poirier, M.; Kudra, T. [Natural Resources Canada, Varennes, PQ (Canada). CANMET Energy Technology Centre

2002-06-01

This paper presents the results of a study in which osmotically pretreated cranberries were dried. The osmotic treatment included dehydration and sugar infusion. The process involved pretreating halved cranberries in a standard osmotic solution followed by freeze-drying, vacuum-drying and air-drying in various dryers, such as cabinet-air-through, fluid bed, pulsed fluid bed, and vibrated fluid bed dryers. The intent was to identify the best drying technology. The comparison criteria selected were energy consumption and product quality. Product quality for freeze-dried berries was quantified based on anthocyanins content, rehydration ratio, color, and taste. Unit heat consumption could be used for selecting the drying method, as all other drying methods yielded similar but slightly lower quality products. The highest energy efficiency was obtained with the vibrated fluid bed and the pulsed fluid bed. It was noted that drying rates were reduced during the second drying period when sugar was infused into the cranberries during osmotic pretreatment, but the total energy consumption was reduced by osmotic dehydration. 22 refs., 1 tab., 5 figs.

Dating the Naisiusiu Beds, Olduvai Gorge, by electron spin resonance

Science.gov (United States)

Skinner, A. R.; Hay, R. L.; Masao, F.; Blackwell, B. A. B.

2003-05-01

The lower beds at Olduvai Gorge are well known for containing early hominid fossils and Oldowan stone tools, and their ages have been established by 40Ar/ 39Ar dating and paleomagnetic stratigraphy. Ages are generally less certain for the upper deposits at Olduvai Gorge because of the scarcity of datable tuffs. The youngest archaeologically significant site at Olduvai is microlithic LSA, which lies in the type section of the Naisiusiu Beds. The age for the site is controversial, with 14C dates of 17,000-17,550 (Hay, R.L., 1976 Geology of Olduvai Gorge, University of California Press, Berkeley) and >42,000 BP (Manega, P.C., 1993. Geochronology, geochemistry, and isotopic study of the Plio-Pleistocene Hominid sites and the Ngorongoro Volcanic Highland in Northern Tanzania. Unpublished Ph.D. Thesis, University of Colorado, Boulder, CO). The tuff bed in the zone with artifacts does not contain materials datable by 40Ar/ 39Ar, and some other dating method was needed. In the summer of 2001, five equid teeth were collected from the type Naisiusiu site. Another tooth had previously been collected. ESR ages have been determined for three teeth from the archaeological level and their ages cluster around 62±5 ka, assuming linear uranium uptake. Another tooth from a level without artifacts and believed to be significantly younger dated to 39±5 ka, again assuming LU. These dates are considerably older than previous estimates and suggest that the East African MSA/LSA transition occurred very early.

Sustainable implementation of solar tunnel dryers, water heaters and cookers in Nepal

Energy Technology Data Exchange (ETDEWEB)

Kovacs, Peter [Danish Energy Management, DEM for Renewable Energy Project, REP, Dhobighat, Lalitpur (Nepal); Shrestha, Niraj; Shakya, Prajwal Raj [Renewable Energy Project, REP, Dhobighat, Lalitpur (Nepal); Pokharel, Govind [Alternative Energy Promotion Centre (AEPC), Lalitpur (Nepal)

2008-07-01

The Renewable Energy Project (REP) is a joint effort of the European Union and the Government of Nepal. Main objectives of the project are to create renewable energy infrastructure and services for the benefit of rural people in remote districts of Nepal. The REP will provide solar energy systems for public services in remote districts, as well as for income generating activities e.g. agro business and tourism. The REP focuses on the installation of institutional PV systems with a total capacity of 0.850 MWp. Concurrently, a number of solar thermal systems are being provided to community organizations (COs) in rural areas of Nepal. The priority applications for the solar thermal part are solar tunnel dryers for small industries drying vegetables. fruits and herbs, solar water heaters for community centers in trekking areas and large scale solar cookers in schools. The paper describes the Renewable Energy Project's implementation program for solar thermal technology and in particular the implications on design and usefulness of the solar tunnel dryer from on-site feasibility studies carried out by the project team. REP provides a framework for a sustainable implementation of these systems by carrying out the whole process from dissemination of information to demand collection, feasibility studies, design, procurement, commissioning and user training. Hand over of ownership will take place once the equipment is installed and successfully commissioned. Monitoring during the first year of operation should conclude the project. REP is co-funded by the European Union and the Government of Nepal. (orig.)

Qualidade fisiológica de sementes de sorgo coletadas em diferentes pontos de um secador Physiological quality of sorghum seeds collected at different points in the dryer

Directory of Open Access Journals (Sweden)

Jadir N. da Silva

2001-12-01

Full Text Available Neste trabalho, avaliou-se a qualidade fisiológica e se quantificaram os possíveis gradientes de umidade de sementes de sorgo BR 601, durante o armazenamento. Utilizaram-se amostras coletadas em secador de camada fixa vertical, com duto central perfurado e distribuição radial de ar. Os pontos amostrais no secador se distanciavam 0,10; 0,30 e 0,50 m em relação à lateral do duto central de ar e nas alturas de 0,85; 2,02 e 3,64 m da base do secador, com capacidade de 8 t, além de uma amostra média (M que representou os três pontos radiais, respectivamente. Armazenou-se o sorgo durante nove meses e se avaliou a germinação, vigor e umidade do produto no terceiro, sexto e nono meses de armazenamento. Não houve diferença na qualidade fisiológica das sementes nas diferentes alturas e distâncias em relação ao duto central de ar do secador, em relação à média (M durante o armazenamento, mas no decorrer deste, a queda de qualidade foi mais evidente no teste de frio, obtida no nono mês de armazenamento.The objective of this work was to evaluate the physiological quality and possible moisture gradients in seeds of sorghum BR 601, during storage. Samples from a vertical fixed-bed dryer with a perforated central duct and radial air distribution were used. In the dryer, the sample points were located at 0.10, 0.30 and 0.50 m distances in relation to the lateral of the central air duct. A composite sample was also collected and used as the control in relation to the others, at the respective heights. These sampling procedures were followed at heights of 0.85; 2.02 and 3.64 m from the dryer base. Within each height and distance relative to the air duct, the collected samples were stored during nine months and evaluated for germination and vigor. At the third, sixth and ninth months after storage, the samples were evaluated for possible differences in quality and seed moisture gradient in comparison to the composite sample. No differences

Design, Construction and Testing of Simple Solar Maize Dryer

Directory of Open Access Journals (Sweden)

Joshua FOLARANMI

2008-12-01

Full Text Available This project reports the design, construction and testing of a simple solar maize dryer. It is design in such a way that solar radiation is not incident directly on the maize, but preheated air warmed during its flow through a low pressure thermosphonic solar energy air heater or collector made up of an insulating material (polystyrene of size 100mmx50mmx25.4mm, absorber plate (aluminium sheet painted black of size 100mmx50mm and a cover glass (5mm thickness measuring 100mmx50mm all arranged in this order contributed to the heating. The test results gave temperature above 45OC in the drying chamber, and the moisture content of 50kg of maize reduced to about 12.5% in three days of 9hours each day of drying.

Test-beds for molecular electronics: metal-molecules-metal junctions based on Hg electrodes.

Science.gov (United States)

Simeone, Felice Carlo; Rampi, Maria Anita

2010-01-01

produced results, are convenient test-beds for molecular electronics and represent a useful complement to physics-based experimental methods.

Drying characteristics of garlic ( Allium sativum L) slices in a convective hot air dryer

Science.gov (United States)

Demiray, Engin; Tulek, Yahya

2014-06-01

The effects of drying temperatures on the drying kinetics of garlic slices were investigated using a cabinet-type dryer. The experimental drying data were fitted best to the Page and Modified Page models apart from other theoretical models to predict the drying kinetics. The effective moisture diffusivities varied from 4.214 × 10-10 to 2.221 × 10-10 m2 s-1 over the temperature range studied, and activation energy was 30.582 kJ mol-1.

Drying of Ceramic Hollow Bricks in an Industrial Tunnel Dryer: A Finite Volume Analysis

OpenAIRE

F Tavares; S Neto; E Barbosa; A Lima; C Silva

2016-01-01

This paper aims to study the drying of industrial hollow bricks in a tunnel dryer cross flow type. The theoretical model is based on mass and energy conservation equations applied to air and product. To validate the methodology, numerical and experimental results for the moisture content and the temperature of brick during the drying in an industrial scale are compared and a good correlation was obtained. Results of moisture content and temperature of the product, and temperature, relative hu...

Investigation of influence of drying agent movement on the drying process effectiveness in the gravitational shelf dryer

Directory of Open Access Journals (Sweden)

N. O. Artyukhova

2017-12-01

Full Text Available The article stands for a research of the drying process efficiency of various approaches of reciprocal movement organization of drying agent and disperse material. It focuses on the results of shelf dryer investigation. The test condition was as follows: backflow of the drying agent and disperse material movement; backflow of the drying agent and disperse material movement with the drying agent recirculation; backflow of the drying agent and disperse material movement with the bypassing of drying agent and it’s putting on separate stage of gravitational shelf dryer. The influence of the drying agent movement organization on the characteristics of disperse material and drying agent, energy costs for this process and its efficiency is shown. The recommendations of usage of represented approaches of flows movement organization depending on the desired final moisture of the material as well as its physical and chemical properties are given. The proposed ways of reciprocal flows movement organization allow to reduce the costs of drying agent heating or to increase the efficiency of moisture removal at constant energy consumption.

Experimental investigation of a novel indirect solar dryer implementing PCM as energy storage medium

Energy Technology Data Exchange (ETDEWEB)

Shalaby, S.M., E-mail: saleh_shalaby@yahoo.com; Bek, M. A.

2014-07-01

Highlights: • The performance of a novel indirect solar dryer is investigated experimentally. • PCM, paraffin wax, is used as energy storage medium. • The novel ISD is suitable for drying medical plants. • Ocimum and Thevetia are dried at their prescribed drying temperatures. • The novel design maintains the desired temperature for 7 consecutive h/day. - Abstract: A novel indirect solar dryer (ISD) design using phase change material (PCM) as energy storage medium was experimentally investigated. The system consists of two identical solar air heaters, drying compartment, PCM storage units and a blower. The ISD was tested under no load with and without PCM at a wide range of mass flow rates (0.0664–0.2182 kg/s). It is found that after using the PCM, the temperature of the drying air is higher than ambient temperature by 2.5–7.5 °C after sunset for five hours at least. In addition, the mass flow rates of 0.1204 and 0.0894 kg/s give the peak values of the drying temperature when the ISD is operated with and without PCM, respectively. The novel design successfully maintains the desired temperature for seven consecutive hours every day. This helps reaching the final moisture content of Ocimum Basilicum and Thevetia Neriifolia after 12 and 18 h, respectively.

Drying kinetics of whole and sliced turmeric rhizomes (Curcuma longa L. in a solar conduction dryer

Directory of Open Access Journals (Sweden)

A. Borah

2015-09-01

Full Text Available Drying of turmeric was carried out in a solar conduction dryer (SCD. Drying air temperature was achieved around 39–51 °C for an ambient temperature in the range of 25–28 °C. Moisture content from 78.65% (wb, was reduced to 6.36% (wb and 5.50% (wb for solid and sliced samples respectively in 12 h effective drying time. Drying curve of sliced samples showed more uniform falling in comparison to that of whole samples. The average effective moisture diffusivity was found to be 1.852 × 10−10 m2 s−1 for slab samples and 1.456 × 10−10 m2 s−1 for solid samples. Out of four models tried for simulation, Page model was found as best fitted thin layer drying model when simulation was done for all the drying data. The overall thermal efficiency of the dryer was found to be 55%. Drying of sliced rhizomes showed better drying kinetics and effective drying time could be reduced by slicing instead of drying in whole form.

Simulation of Solar Heat Pump Dryer Directly Driven by Photovoltaic Panels

Science.gov (United States)

Houhou, H.; Yuan, W.; Wang, G.

2017-05-01

This paper investigates a new type of solar heat pump dryer directly driven by photovoltaic panels. In order to design this system, a mathematical model has been established describing the whole drying process, including models of key components and phenomena of heat and mass transfer at the product layer and the air. The results of simulation at different drying air temperatures and velocities have been calculated and it indicate that the temperature of drying air is crucial external parameter compared to the velocity, with the increase of drying temperature from 45°C to 55°C, the product moisture content (Kg water/Kg dry product) decreased from 0.75 Kg/Kg to 0.3 Kg/Kg.

Infant's bed climate and bedding in the Japanese home.

Science.gov (United States)

Nakamura Ikeda, Rie; Fukai, Kiyoko; Okamoto Mizuno, Kazue

2012-06-01

to assess the bed climate of infants in their homes in Japan. descriptive, exploratory, non-experimental research design. the data were collected at the participants' homes under normal circumstances. nineteen healthy infants between the ages of two and five months. Their mothers, who joined a parenting class organised by a maternity clinic in Okayama, Japan, consented to participate in this study. we visited the infants' homes and interviewed their mothers concerning the types and use of bedding. The temperature and relative humidity of the bed climate at the back and foot of the bedding, and in the room were measured every minute for four consecutive days. Differences among the bed climates measured during three seasons (spring, summer, and autumn) were assessed by one-way analysis of variance. The bed temperature was higher for infants than for adults. No significant difference in temperature was noted among the three seasons. The bed temperature was about 36.0°C when waterproof sheets and futon mattresses for children or adult were used. The average relative humidity of the bed climate at the back was highest in summer, followed by that in spring and autumn; the differences were significant. The use of waterproof sheets and futon mattresses for children in summer increased the relative humidity to 80% or more. The use of infant beds, sunoko drainboards, and cotton futon mattresses in summer was effective in reducing the bed humidity. these results suggest that nurse-midwives should advise the parents on comfortable bed climates for their infants, as well as how to select and use bedding for them. Copyright © 2010 Elsevier Ltd. All rights reserved.

The influence of fine char particles burnout on bed agglomeration during the fluidized bed combustion of a biomass fuel

Energy Technology Data Exchange (ETDEWEB)

Scala, Fabrizio; Chirone, Riccardo [Istituto di Ricerche sulla Combustione, CNR, P.le V. Tecchio, 80-80125 Naples (Italy); Salatino, Piero [Dipartimento di Ingegneria Chimica, Universita degli Studi di Napoli Federico II, P.le V. Tecchio, 80-80125 Naples (Italy)

2003-11-15

The combustion of biomass char in a bubbling fluidized bed is hereby addressed, with specific reference to the influence that the combustion of fine char particles may exert on ash deposition and bed agglomeration phenomena. Experiments of steady fluidized bed combustion (FBC) of powdered biomass were carried out with the aim of mimicking the postcombustion of attrited char fines generated in the fluidized bed combustion of coarse char. Experimental results showed that the char elutriation rate is much smaller than expected on the basis of the average size of the biomass powder and of the carbon loading in the combustor. Samples of bed material collected after prolonged operation of the combustor were characterized by scanning electron microscopy (SEM)-EDX analysis and revealed the formation of relatively coarse sand-ash-carbon aggregates. The phenomenology is consistent with the establishment of a char phase attached to the bed material as a consequence of adhesion of char fines onto the sand particles. Combustion under sound-assisted fluidization conditions was also tested. As expected, enhancement of fines adhesion on bed material and further reduction of the elutriation rate were observed. Experimental results are interpreted in the light of a simple model which accounts for elutriation of free fines, adhesion of free fines onto bed material and detachment of attached fines by attrition of char-sand aggregates. Combustion of both free and attached char fines is considered. The parameters of the model are assessed on the basis of the measured carbon loadings and elutriation rates. Model computations are directed to estimate the effective size and the peak temperature of char-sand aggregates. The theoretical estimates of the effective aggregate size match fairly well those observed in the experiments.

Modification of Indirect Solar Dryer for Simplicia Production

Science.gov (United States)

Purnomo, C. W.; Indarti, S.

2018-03-01

Simplicia is natural ingredient for herbal medicine that has been subjected to drying only. This study aims to develop an appropriate drying equipment to produce dried leaves of sambung nyawa (Gynura procumbens (Lour.) Merr.) or also called “longevity spinach”. Typical indirect solar drier was modified to be able to process more fresh leaves in order to speed up the production. The modification was done using double solar collector and wind powered ventilation. The double solar collector was applied in order to collect more solar energy for larger dimension of drying chamber, while the wind-ventilator was installed to provide forced convection of hot air flow inside the dryer. The drying kinetic including the drying constants were investigated using three common thin layer drying equations to model the drying behavior of the leaves. The moisture ratio (MR) depletion with respect to the drying time (t) of the leaves can be well represented by equation of MR=1.1732exp(-0.0993.t)-0.1732exp(-17.3871.t).

Bed Bugs

Science.gov (United States)

Prevent, identify, and treat bed bug infestations using EPA’s step-by-step guides, based on IPM principles. Find pesticides approved for bed bug control, check out the information clearinghouse, and dispel bed bug myths.

Drying process optimization for an API solvate using heat transfer model of an agitated filter dryer.

Science.gov (United States)

Nere, Nandkishor K; Allen, Kimberley C; Marek, James C; Bordawekar, Shailendra V

2012-10-01

Drying an early stage active pharmaceutical ingredient candidate required excessively long cycle times in a pilot plant agitated filter dryer. The key to faster drying is to ensure sufficient heat transfer and minimize mass transfer limitations. Designing the right mixing protocol is of utmost importance to achieve efficient heat transfer. To this order, a composite model was developed for the removal of bound solvent that incorporates models for heat transfer and desolvation kinetics. The proposed heat transfer model differs from previously reported models in two respects: it accounts for the effects of a gas gap between the vessel wall and solids on the overall heat transfer coefficient, and headspace pressure on the mean free path length of the inert gas and thereby on the heat transfer between the vessel wall and the first layer of solids. A computational methodology was developed incorporating the effects of mixing and headspace pressure to simulate the drying profile using a modified model framework within the Dynochem software. A dryer operational protocol was designed based on the desolvation kinetics, thermal stability studies of wet and dry cake, and the understanding gained through model simulations, resulting in a multifold reduction in drying time. Copyright © 2012 Wiley-Liss, Inc.

Comparison of Linear and Nonlinear Model Predictive Control for Optimization of Spray Dryer Operation

DEFF Research Database (Denmark)

Petersen, Lars Norbert; Poulsen, Niels Kjølstad; Niemann, Hans Henrik

2015-01-01

In this paper, we compare the performance of an economically optimizing Nonlinear Model Predictive Controller (E-NMPC) to a linear tracking Model Predictive Controller (MPC) for a spray drying plant. We find in this simulation study, that the economic performance of the two controllers are almost...... equal. We evaluate the economic performance with an industrially recorded disturbance scenario, where unmeasured disturbances and model mismatch are present. The state of the spray dryer, used in the E-NMPC and MPC, is estimated using Kalman Filters with noise covariances estimated by a maximum...

Design and measured performance of a solar chimney for natural-circulation solar-energy dryers

International Nuclear Information System (INIS)

Ekechukwu, O.V.; Norton, B.

1995-10-01

The design and construction of a solar chimney which was undertaken as part of a study on natural-circulation solar-energy dryers is reported. The experimental solar chimney consists of a 5.3m high and 1.64m diameter cylindrical polyethylene-clad vertical chamber, supported structurally by steel framework and draped internally with a selectively-absorbing surface. The performance of the chimney which was monitored extensively with and without the selective surface in place (to study the effectiveness of this design option) is also reported. (author). 14 refs, 7 figs

Bed agglomeration characteristics of palm shell and corncob combustion in fluidized bed

International Nuclear Information System (INIS)

Chaivatamaset, Pawin; Sricharoon, Panchan; Tia, Suvit

2011-01-01

Bed particle agglomeration was studied experimentally in an atmospheric laboratory scale fluidized bed combustor using quartz sand as bed material. Palm shell and corncob were tested. The objectives of the study were (i) to describe the contributions of the biomass ash properties and the operating conditions on the bed agglomeration tendency in term of the bed defluidization time (t def ) and the extent of potassium accumulation in the bed (K/Bed) and (ii) to further elucidate the ash inorganic behaviors and the governing bed agglomeration mechanisms. Defluidization caused by the bed agglomeration was experienced in all experiments during combustion of these biomasses, as a consequence of the presence of potassium in biomass. The experimental results indicated that biomass ash characteristics were the significant influence on the bed agglomeration. The increasing bed temperature, bed particle size and static bed height and the decreasing fluidizing air velocity enhanced the bed agglomeration tendency. The SEM/EDS analyses on the agglomerates confirmed that the agglomeration was attributed to the formation of potassium silicate liquid enriched on the surface of quartz sand particles in conjunction with the high surface temperature of the burning biomass char particles. Thermodynamic examination based on the phase diagram analysis confirmed that the molten phase formation was responsible for the agglomeration. In this study, the high molten ash fraction resulting from the high potassium content in biomass promoted the agglomeration and thus defluidization. - Highlights: → Palm shell and corncob of Thailand are tested their bed agglomeration behaviors during fluidized bed combustion. → The increase of bed temperature, bed particle size and static bed height and the decrease of air velocity enhance bed agglomeration. → The formation of ash derived potassium silicate melts enriched on sand surface is the key process. → The collision between char and sand

The characteristics of bed agglomeration during fluidized bed combustion of eucalyptus bark

International Nuclear Information System (INIS)

Chaivatamaset, Pawin; Tia, Suvit

2015-01-01

The bed agglomeration behaviors were investigated experimentally when eucalyptus bark was burning tested in a laboratory scale fluidized bed reactor. The focuses of this work were the influences of operating conditions and bed materials on the bed agglomeration tendency and the elucidation in the behaviors of fuel inorganic elements and the governing mode of the agglomeration. It was found that the defluidization caused by the bed agglomeration was clearly detectable from the decrease in measured bed pressure. The growth of bed particle and accumulation of agglomerates during combustion provided the partial to complete defluidization. The defluidization was promoted by the increase of bed temperature and bed particle size, and the decrease of fluidizing air velocity. The SEM-EDS analyses revealed that the bed agglomeration was mainly attributed to the formation of potassium silicate compounds as liquid phase during the combustion. This was initiated by the chemical reaction between the bed particle and the released ash constituents. In this study, the inorganic migration from fuel particle to bed particle was likely dominated by the condensation/reaction. The thermodynamic examination by ternary phase diagram analysis corroborated that the liquid phase formation of the ash derived materials controlled the agglomeration. The alumina sand prevented the bed agglomeration since it was inactive in the formation of viscous molten substances during combustion at the observed temperatures. - Highlights: • The behaviors of bed agglomeration were studied during the fluidized bed combustion of eucalyptus bark. • The increase in bed temperature and sand size, and the decrease of air velocity promoted bed defluidization. • The formation of molten potassium silicate compounds conduced to the bed agglomeration. • Condensation/reaction was the dominant inorganic migration mechanism from fuel particle to bed particle. • The alumina sand prevented effectively the bed

Mushrooms dehydration in a hybrid-solar dryer, using a phase change material

International Nuclear Information System (INIS)

Reyes, Alejandro; Mahn, Andrea; Vásquez, Francisco

2014-01-01

Highlights: • Mushroom slices were dehydrated in a hybrid solar dryer. • Drying and dehydrated kinetics were adjusted with models. • Effective diffusivity, were estimated considering or not shrinkage. • Paraffin wax as a phase change material was used in an accumulator of solar energy. - Abstract: Mushrooms were dehydrated in a hybrid solar dryer provided with a solar panel of a total exposed surface of 10 m 2 , electric resistances and paraffin wax as a phase change material. Mushrooms were cut in 8 mm or 12 mm slices. At the outlet of the drying chamber the air was recycled (70% or 80%) and the air temperature was adjusted to 60 °C. At the outlet of the solar panel the air temperature rose up to 30 °C above the ambient temperature, depending on solar radiation level. The effective diffusivity, estimated by the Simplified Constant Diffusivity Model, considering or not shrinkage, fluctuated between 2.5 · 10 −10 m 2 /s and 8.4 · 10 −10 m 2 /s with R 2 higher than 0.99, agreeing with values reported in literature. The empirical Page’s model resulted in a better adjustment, with R 2 above 0.998. In all runs the dehydrated mushrooms showed a notorious darkening and shrinkage. Rehydration assays at 30 °C showed that in less than 30 min rehydrated mushrooms reached a moisture content of 1.91 (dry basis). Rehydrated mushrooms had a higher hardness compared with fresh mushrooms. The Simplified Constant Diffusivity Model and the Peleg’s model adjusted to the rehydration data with RMSE values below 0.080. Thermal efficiency fluctuated between 22% and 62%, while the efficiency of the accumulator panel varied between 10% and 21%. The accumulator allowed reducing the electric energy input

Analysis of efficiency of a solar dryer tunnel type of mango pulp; Analisis de la eficiencia de un secador solar tipo tunel para pulpa de mango

Energy Technology Data Exchange (ETDEWEB)

Chagoyan Serrano, Jose [Universidad Autonoma de Baja California Sur, La Paz, Baja California Sur (Mexico)

2000-07-01

A new method to assess the performance of a solar dryer is presented. It describes energy efficiency indicators to improve a commercial dryer design. First, a preliminary dryer design procedure is described step by step. Then, two different modes of a tunnel dryer are investigated: Batch and semi-continue operations. The results of the analysis show that, the thermal efficiency is not sufficient to rate de dryer performance. It is necessary to include the productivity of the drying process and the quality of the dried fruit. The drying process and productivity tend to go hand-in-hand but in opposite directions. That is to say, raising the thermal efficiency reduce the process productivity and conversely. The analysis also suggests that an agreement between the efficiency, productivity and the quality must be specified in the drier design. [Spanish] Se presenta un procedimiento nuevo para evaluar la operacion de un secador solar, con el cual se precisan indicadores de la eficiencia que pueden ser utiles para mejorar el diseno del equipo. Se empieza por describir los pasos de un procedimiento de diseno preliminar de un sistema de secado. Despues, se analizan cualitativamente dos secadores: uno que opera por lotes y el otro de modo semicontinuo. Los resultados del analisis muestran que, la eficiencia termica del equipo no es un criterio suficiente para evaluar su operacion; tambien se requiere tomar encuenta la productividad del proceso de secado y la calidad del producto final. Se concluye que la eficiencia termica y la productividad del proceso son conceptos encontrados. Es decir, la eficiencia termica del equipo no es un criterio suficiente para evaluar su operacion; tambien se requiere tomar en cuenta la productividad del proceso de secado y la calidad del producto final. Se concluye que la eficiencia termica y la productividad del proceso son conceptos encontrados. Es decir, la eficiencia termica solo se puede aumentar a costa de la productividad y viceversa

Two-dimensional mathematical model for simulation of the drying process of thick layers of natural materials in a conveyor-belt dryer

Directory of Open Access Journals (Sweden)

Salemović Duško R.

2017-01-01

Full Text Available This paper presents the mathematical model and numerical analysis of the convective drying process of thick slices of colloidal capillary-porous materials slowly moving through conveyor-belt dryer. A flow of hot moist air was used as drying agent. The drying process has been analyzed in the form of a 2-D mathematical model, in two directions: along the conveyor and perpendicular on it. The mathematical model consists of two non-linear differential equations and one equation with a transcendent character and it is based on the mathematical model developed for drying process in a form of a 1-D thin layer. The appropriate boundary conditions were introduced. The presented model is suitable for the automated control of conveyor-belt dryers. The obtained results with analysis could be useful in predicting the drying kinetics of potato slices and similar natural products.

Developing and evaluating a meeting assistant test bed

NARCIS (Netherlands)

Post, W.M.; Lincoln, M.

2008-01-01

A test bed has been developed in which participants are tasked to work in simulated, scenario based, projects in which face-to-face and remote meetings of about 45 minutes have to be held. Measures on performance, team factors and remote aspects are automatically collected with electronic

Assessment of the environmental microbiological cross contamination following hand drying with paper hand towels or an air blade dryer.

Science.gov (United States)

Margas, E; Maguire, E; Berland, C R; Welander, F; Holah, J T

2013-08-01

This study compared the potential for cross contamination of the surrounding environment resulting from two different hand-drying methods: paper towels and the use of an air blade dryer. One hundred volunteers for each method washed their hands and dried them using one of the two methods. Bacterial contamination of the surrounding environment was measured using settle plates placed on the floor in a grid pattern, air sampling and surface swabs. Both drying methods produced ballistic droplets in the immediate vicinity of the hand-drying process. The air blade dryer produced a larger number of droplets which were dispersed over a larger area. Settle plates showed increased microbial contamination in the grid squares which were affected by ballistic droplets. Using the settle plates counts, it was estimated that approx. 1.7 × 10(5) cfu more micro-organisms were left on the laboratory floor (total area approx. 17.15 m(2)) after 100 volunteers used an air blade dryer compared to when paper towels were used. The two drying methods led to different patterns of ballistic droplets and levels of microbial contamination under heavy use conditions. Whilst the increase in microbial levels in the environment is not significant if only nonpathogenic micro-organisms are spread, it may increase the risk of pathogen contamination of the environment when pathogens are occasionally present on people's hands. The study suggests that the risk of cross contamination from the washroom users to the environment and subsequent users should be considered when choosing a hand-drying method. The data could potentially give guidance following the selection of drying methods on implementing measures to minimise the risk of cross contamination. © 2013 The Society for Applied Microbiology.

Bed management team with Kanban web-based application.

Science.gov (United States)

Rocha, Hermano Alexandre Lima; Santos, Ana Kelly Lima da Cruz; Alcântara, Antônia Celia de Castro; Lima, Carmen Sulinete Suliano da Costa; Rocha, Sabrina Gabriele Maia Oliveira; Cardoso, Roberto Melo; Cremonin, Jair Rodrigues

2018-05-15

To measure the effectiveness of the bed management process that uses a web-based application with Kanban methodology to reduce hospitalization time of hospitalized patients. Before-after study was performed. The study was conducted between July 2013 and July 2017, at the Unimed Regional Hospital of Fortaleza, which has 300 beds, of which 60 are in the intensive care unit (ICU). It is accredited by International Society for Quality in Healthcare. Patients hospitalized in the referred period. Bed management with an application that uses color logic to signal at which stage of high flow the patients meet, in which each patient is interpreted as a card of the classical Kanban theory. It has an automatic user signaling system for process movement, and a system for monitoring and analyzing discharge forecasts. Length of hospital stay, number of customer complaints related to bed availability. After the intervention, the hospital's overall hospital stay time was reduced from 5.6 days to 4.9 days (P = 0.001). The units with the greatest reduction were the ICUs, with reduction from 6.0 days to 2.0 (P = 0.001). The relative percentage of complaints regarding bed availability in the hospital fell from 27% to 0%. We conclude that the use of an electronic tool based on Kanban methodology and accessed via the web by a bed management team is effective in reducing patients' hospital stay time.

The Safety of Hospital Beds: Ingress, Egress, and In-Bed Mobility.

Science.gov (United States)

Morse, Janice M; Gervais, Pierre; Pooler, Charlotte; Merryweather, Andrew; Doig, Alexa K; Bloswick, Donald

2015-01-01

To explore the safety of the standard and the low hospital bed, we report on a microanalysis of 15 patients' ability to ingress, move about the bed, and egress. The 15 participants were purposefully selected with various disabilities. Bed conditions were randomized with side rails up or down and one low bed with side rails down. We explored the patients' use of the side rails, bed height, ability to lift their legs onto the mattress, and ability to turn, egress, and walk back to the chair. The standard bed was too high for some participants, both for ingress and egress. Side rails were used by most participants when entering, turning in bed, and exiting. We recommend that side rails be reconsidered as a means to facilitate in-bed movement, ingress, and egress. Furthermore, single deck height settings for all patients are not optimal. Low beds as a safety measure must be re-evaluated.

Energy and exergy analyses of native cassava starch drying in a tray dryer

International Nuclear Information System (INIS)

Aviara, Ndubisi A.; Onuoha, Lovelyn N.; Falola, Oluwakemi E.; Igbeka, Joseph C.

2014-01-01

Energy and exergy analyses of native cassava starch drying in a tray dryer were carried out to assess the performance of the system in terms of energy utilization, energy utilization ratio, energy efficiency, exergy inflow and outflow, exergy loss and exegetic efficiency. The results indicated that for the starch with ash content of 0.76%, 0.85% crude protein, 0.16% crude fat, negligible amount of fiber, average granule size of 14.1 μm, pH of 5.88, amylose content of 23.45% and degree of crystallinity of 22.34%, energy utilization and energy utilization ratio increased from 1.93 to 5.51 J/s and 0.65 to 0.6 as the drying temperature increased from 40 to 60 °C. Energy efficiency increased from 16.036 to 30.645%, while exergy inflow, outflow and losses increased from 0.399 to 2.686, 0.055 to 0.555 and 0.344 to 2.131 J/s respectively in the above temperature range. Exergetic efficiency increased with increase in both drying air temperature and energy utilization and was lower than energy efficiency. Exergetic improvement potential also increased with increase in drying air temperature. Model equations that could be used to express the energy and exergy parameters as a function of drying temperature were established. - Highlights: • Energy and exergy analyses of cassava starch drying in a tray dryer were carried out. • Energy utilization increased with drying temperature. • Energy efficiency was higher than exergy efficiency. • Energy and exergy efficiencies increased with increase in temperature. • Improvement potential increased with increase in temperature

Experimental investigation of an indirect solar dryer integrated with phase change material for drying valeriana jatamansi (medicinal herb

Directory of Open Access Journals (Sweden)

A.K. Bhardwaj

2017-09-01

Full Text Available In this study, an experimental investigation of an indirect solar dryer integrated with phase change material has been carried out for drying Valeriana Jatamansi. The experimentation has been performed under the climatic conditions of Himalayan region, Solan (latitude − 30.91°N, longitude − 77.09°E, Himachal Pradesh (India in the month of October-November 2016. Paraffin RT-42 has been used as a phase change material in the dryer. Using this system, the moisture content of rhizomes reduced from 89% to 9% in 5 days as compared to heat pump drying and shade drying, which took 8 days and 14 days, respectively. Results of present study infer that the drying time using phase change material in this setup has reduced by 37.50% and 64.29% when compared to heat pump drying and shade drying, respectively. The dried rhizomes obtained are of superior quality in terms of colour, texture, aroma and bio-medical constituents. Analyses show that by using present setup, total valepotriates obtained were 3.47% as compared to traditional shade drying which yield 3.31%.

Investigations of a type 316L steam dryer plate material suffering from IGSCC after few years in BWRs

International Nuclear Information System (INIS)

Autio, J.M.; Ehrnsten, U.; Pakarinen, J.; Mouginot, R.; Cocco, M.

2015-01-01

A steam dryer plate material suffered from intergranular stress corrosion cracking after only one and two years of operation in two BWR plants. Numerous indications were observed on the inner roof plates of the steam dryers adjacent to the support beam welds. The material was Type 316L austenitic stainless steel with carbon content below 0.02%. The material was subjected to detailed investigations using optical microscopy, EBSD/SEM, TEM, hardness and nano-indentation. The material showed macro-segregation through the plate thickness. These bands coincided with the location of delta-ferrite islands indicating non-optimal solution heat treatment. α'-martensite was observed deep in the plate indicating cold deformation after solution annealing. A nonhomogeneous distribution of grain orientation was also observed through the plate thickness. Further, surface deformation, although not extending very deep, was observed using EBSD and surface hardness values above 300 HV when measured using small loads. Although the material fulfills the set requirements, the material characteristics have obviously increased the susceptibility of the material to IGSCC. The paper will discuss the possible role of changes in manufacturing over the years and the challenges in quality definitions in material specifications. (authors)

7 CFR 2902.15 - Bedding, bed linens, and towels.

Science.gov (United States)

2010-01-01

... PROCUREMENT Designated Items § 2902.15 Bedding, bed linens, and towels. (a) Definition. (1) Bedding is that... minimum biobased content is 12 percent and shall be based on the amount of qualifying biobased carbon in..., and silk are not qualifying biobased feedstocks for the purpose of determining the biobased content of...

Building solar dryer of tropical woods; Construccion de un secador solar de maderas tropicales

Energy Technology Data Exchange (ETDEWEB)

Hernandez R, J; Flores M, F. E; Cuevas D, O [Universidad de Quintana Roo, Chetumal, Quintana Roo (Mexico); Tolentino E, G [LABINTHAP-SEPI-ESIME-IPN, Mexico, D.F. (Mexico)

2000-07-01

In Quintana Roo, Mexico, several species of wood are used for handicrafts. The most commonly method used in the communities nearby Chetumal is natural drying, with the disadvantage of low quality in their products because the moisture contains in the wood. In this project studied the design of solar dryer for tropical woods in Quintana Roo. [Spanish] En este trabajo, se parte del analisis de las condiciones climatologicas existentes en el estado de Quintana Roo, Mexico, asi como de las necesidades de madera seca de una comunidad, como parametros basicos para el diseno y construccion de un secador solar de maderas tropicales.

Design and performance of a Nafion dryer for continuous operation at CO2 and CH4 air monitoring sites

Directory of Open Access Journals (Sweden)

L. R. Welp

2013-05-01

Full Text Available In preparation for routine deployment in a network of greenhouse gas monitoring stations, we have designed and tested a simple method for drying ambient air to near or below 0.2% (2000 ppm mole fraction H2O using a Nafion dryer. The inlet system was designed for use with cavity ring-down spectrometer (CRDS analyzers such as the Picarro model G2301 that measure H2O in addition to their principal analytes, in this case CO2 and CH4. These analyzers report dry-gas mixing ratios without drying the sample by measuring H2O mixing ratio at the same frequency as the main analytes, and then correcting for the dilution and peak broadening effects of H2O on the mixing ratios of the other analytes measured in moist air. However, it is difficult to accurately validate the water vapor correction in the field. By substantially lowering the amount of H2O in the sample, uncertainties in the applied water vapor corrections can be reduced by an order of magnitude or more, thus eliminating the need to determine instrument-specific water vapor correction coefficients and to verify the stability over time. Our Nafion drying inlet system takes advantage of the extra capacity of the analyzer pump to redirect 30% of the dry gas exiting the Nafion to the outer shell side of the dryer and has no consumables. We tested the Nafion dryer against a cryotrap (−97 °C method for removing H2O and found that in wet-air tests, the Nafion reduces the CO2 dry-gas mixing ratios of the sample gas by as much as 0.1 ± 0.01 ppm due to leakage across the membrane. The effect on CH4 was smaller and varied within ± 0.2 ppb, with an approximate uncertainty of 0.1 ppb. The Nafion-induced CO2 bias is partially offset by sending the dry reference gases through the Nafion dryer as well. The residual bias due to the impact of moisture differences between sample and reference gas on the permeation through the Nafion was approximately −0.05 ppm for CO2 and varied within ± 0.2 ppb for CH4. The

Evaluation of a clay-based acidic bedding conditioner for dairy cattle bedding.

Science.gov (United States)

Proietto, R L; Hinckley, L S; Fox, L K; Andrew, S M

2013-02-01

This study investigated the effects of a clay-based acidic bedding conditioner on sawdust bedding pH, dry matter (DM), environmental pathogen counts, and environmental bacterial counts on teat ends of lactating dairy cows. Sixteen lactating Holstein cows were paired based on parity, days in milk, milk yield, and milk somatic cell count, and were negative for the presence of an intramammary pathogen. Within each pair, cows were randomly assigned to 1 of 2 treatments with 3-wk periods in a crossover design. Treatment groups consisted of 9 freestalls per group bedded with either untreated sawdust or sawdust with a clay-based acidic bedding conditioner, added at 3- to 4-d intervals over each 21-d period. Bedding and teat ends were aseptically sampled on d 0, 1, 2, 7, 14, and 21 for determination of environmental bacterial counts. At the same time points, bedding was sampled for DM and pH determination. The bacteria identified in the bedding material were total gram-negative bacteria, Streptococcus spp., and coliform bacteria. The bacteria identified on the teat ends were Streptococcus spp., coliform bacteria, and Klebsiella spp. Teat end score, milk somatic cell count, and intramammary pathogen presence were measured weekly. Bedding and teat cleanliness, environmental high and low temperatures, and dew point data were collected daily. The bedding conditioner reduced the pH, but not the DM, of the sawdust bedding compared with untreated sawdust. Overall environmental bacterial counts in bedding were lower for treated sawdust. Total bacterial counts in bedding and on teat ends increased with time over both periods. Compared with untreated sawdust, the treated bedding had lower counts of total gram-negative bacteria and streptococci, but not coliform counts. Teat end bacterial counts were lower for cows bedded on treated sawdust for streptococci, coliforms, and Klebsiella spp. compared with cows bedded on untreated sawdust. The clay-based acidic bedding conditioner

Secagem de café em combinação A combined system for coffee drying

Directory of Open Access Journals (Sweden)

Adilio F. de Lacerda Filho

2006-09-01

Full Text Available Objetivou-se avaliar um sistema de secagem de café, com meia-seca em leito fixo e complementação da secagem em secador de lotes, intermitente, de fluxos concorrentes, em um experimento instalado na Área de Pré-processamento e Armazenamento de Produtos Vegetais, DEA-UFV. Utilizou-se delineamento inteiramente casualizado. Fez-se a colheita pelo método de derriça sobre o chão. Os frutos foram pré-processados por via seca, secando-se os frutos verdes, cerejas e passas. Na meia-seca, a umidade inicial dos frutos variou entre 68,9 e 71,3% b.u. e a final entre 44,0 e 47,5% b.u. Na complementação da secagem a umidade final variou entre 12,2 e 13,8% b.u. A temperatura do ar, no secador de leito fixo, variou entre 50,4 e 76 °C, e no de fluxos concorrentes, entre 87,2 e 110 °C. A entalpia específica no secador de leito fixo variou entre 8,4 e 9,1 MJ kg-1 e no de fluxos concorrentes, entre 7,1 e 16,9 MJ kg-1. Relativamente às testemunhas, a qualidade final do produto apresentou melhores características comerciais. Concluiu-se que a meia-seca em leito fixo e a secagem em secador de fluxos concorrentes, além de reduzir o tempo de operação, poderá contribuir para melhor preservar as qualidades que o produto adquire no campo.The general objective of this study was the evaluation of a system for coffee drying, using partial drying in fixed bed dryer and complementary drying in an intermittent concurrent flow batch dryer. The experiment was carried out in the Vegetable Products Processing Area, DEA-UFV. The drying tests were accomplished in completely randomized design. The coffee was harvested on the ground by manual striping process. The fruits were pre-processed by drying of ripe, overripe and greenish cherries. For the preliminary drying, the initial coffee moisture content varied from 68.9 to 71.3% w.b. with the drying being interrupted with moisture content between 44.0 and 47.5% w.b. In the complementary drying phase the final moisture

Evaluation of Heat Shields from RTS Wright Industries Magnesium and Uranium Beds

CERN Document Server

Korinko, P S

2002-01-01

Heat shields from a factory test of the furnaces that will be used to heat the magnesium and uranium beds for the tritium extraction facility (TEF) were examined to determine the cause of discoloration. The samples were examined using visual, optical microscopy, electron microscopy, x-ray spectroscopy, and Auger electron spectroscopy.

Drying wood waste with a pulse combustion dryer

Energy Technology Data Exchange (ETDEWEB)

Buchkowski, A.G. [Spectrum Engineering Corp., Ltd., Peterborough, Ontario (Canada); Kitchen, J.A. [John A. Kitchen, Ltd., Hastings, Ontario (Canada)

1993-12-31

There is a vast amount of wood waste available to be used as an alternate fuel if its moisture could be reduced efficiently. Tests have been conducted to assess an industrial dryer using pulse combustion as a heating source for drying wood waste; specifically sawdust and pulverized wet hog fuel. Pulse combustion offers the advantage of high heat transfer, efficient combustion, and low NO{sub x} emissions. The material is injected into the exhaust gases in the tailpipe of the combustor which uses natural gas or propane as a fuel. The turbulence created by the pulsations enhance the drying process by reducing the boundary layer thicknesses. The materials is further dried in a rotary drum. The material has been dried without scorching or burning in tests where the inlet moisture content has been as high as 60% on a wet basis. The outlet moisture contents achieved have typically been 10%. Analysis of the test data and cost estimates of the equipment indicate that the pulse combustion drying system is at least comparable to existing systems in terms of operating costs, and offers very significant savings in capital costs. Testing with various other materials such as wood pulp, sludges and peat is continuing to further assess the equipment`s performance.

Determination of stresses caused by fluctuation of acoustic load in the steam dryers of a BWR; Determinacion de esfuerzos originados por fluctuacion de carga acustica en los secadores de vapor de un reactor BWR

Energy Technology Data Exchange (ETDEWEB)

Centeno P, J.; Quezada G, S.; Prieto G, A.; Vazquez R, A.; Espinosa P, G. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco No. 186, Col. Vicentina, 09340 Mexico D. F. (Mexico); Nunez C, A., E-mail: javcuami26@hotmail.com [Comision Nacional de Seguridad Nuclear y Salvaguardias, Dr. Jose Ma. Barragan No. 779, Col. Narvarte, 03020 Mexico D. F. (Mexico)

2014-10-15

The extended power up-rate (EPU) in a nuclear power plant cause various problems in BWR components also in the steam system. This due to increased steam flow generated in the reactor and is conveyed to the turbine by the four main steam lines (MSL). One of the most serious problems is the generation of acoustic pressure loads in the metal structure of the steam dryer which eventually leads to fatigue failure and even the appearance of cracks, and in turn it causes loose parts that are entrained by the steam and transported in the MSL. This problem is due to the fluctuation of load acoustics caused by the union of the safety or relief valves (SRV) with the MSL, spreading through these to reach the reactor pressure vessel (RPV) where the effect of resonance of the acoustic wave is amplified and impacts directly in the supporting structure of the steam dryer, skirt and the panels where the mixture liquid-steam is dried, by centrifugation effect and runoff of liquid water. Efforts in the steam dryer operating conditions of EPU for two cases will be analyzed in this work, the first is before the installation of Acoustic Side Branch (ASB), and in the second case we consider the installation of said ASB in the standpipes of SRV. The analysis was performed with numerical experiments on a platform for computational fluid dynamics with virtual geometries previously designed based on the actual components of the reactor and steam system. The model to study is delimited by the top of the RPV, the steam dryer and a section of each of the four MSL with ten standpipes of SRV. With the obtained data and considering the mechanical-structural properties of the steam dryer material, we can evaluate the mechanical resistance to impacts by acoustic pressure load and its possible deformation or cracking. (Author)

Tritium effluent removal system

International Nuclear Information System (INIS)

Lamberger, P.H.; Gibbs, G.E.

1978-01-01

An air detritiation system has been developed and is in routine use for removing tritium and tritiated compounds from glovebox effluent streams before they are released to the atmosphere. The system is also used, in combination with temporary enclosures, to contain and decontaminate airborne releases resulting from the opening of tritium containment systems during maintenance and repair operations. This detritiation system, which services all the tritium handling areas at Mound Facility, has played an important role in reducing effluents and maintaining them at 2 percent of the level of 8 y ago. The system has a capacity of 1.7 m 3 /min and has operated around the clock for several years. A refrigerated in-line filtration system removes water, mercury, or pump oil and other organics from gaseous waste streams. The filtered waste stream is then heated and passed through two different types of oxidizing beds; the resulting tritiated water is collected on molecular sieve dryer beds. Liquids obtained from regenerating the dryers and from the refrigerated filtration system are collected and transferred to a waste solidification and packaging station. Component redundancy and by-pass capabilities ensure uninterrupted system operation during maintenance. When processing capacity is exceeded, an evacuated storage tank of 45 m 3 is automatically opened to the inlet side of the system. The gaseous effluent from the system is monitored for tritium content and recycled or released directly to the stack. The average release is less than 1 Ci/day. The tritium effluent can be reduced by isotopically swamping the tritium; this is accomplished by adding hydrogen prior to the oxidizer beds, or by adding water to the stream between the two final dryer beds

Solar dryers for a non-polluting removal of sewage sludge; Solartrockner fuer eine umweltfreundliche Klaerschlammentsorgung

Energy Technology Data Exchange (ETDEWEB)

Kos, Manfred [Lenze, Hameln (Germany)

2011-06-15

The acceptance of solar drying technology is depending on the quality of the produced dry goods. On local markets as well as for the export market dryed products can only compete if they can meet the quality standards of the food processing industry and consumers. A high added value for operators of solar dryers especially from developing countries can only be achieved if the goods can be exported. Dried sewage sludge shows to have an energy density corresponding to brown coal, burns however carbon dioxide neutrally compared with fossil fuels and grows continuously in water treatment plants on the outskirts of cities. (GL)

Aerosol sampling of an experimental fluidized bed coal combustor

International Nuclear Information System (INIS)

Newton, G.J.; Peele, E.R.; Carpenter, R.L.; Yeh, H.C.

1977-01-01

Fluidized bed combustion of coal, lignite or other materials has a potential for widespread use in central electric generating stations in the near future. This technology may allow widespread use of low-grade and/or high sulfur fuels due to its high energy utilization at low combustion temperature and its ability to meet emission criteria by using limestone bed material. Particulate and gaseous products resulting from fuel combustion and fluidization of bed material are discharged and proceed out the exhaust clean-up system. Sampling philosophy, methodology and equipment used to obtain aerosol samples from the exhaust system of the 18-inch fluidized bed combustor (FBC) at the Morgantown Energy Research Center (MERC) are described. Identification of sampling sites led to design of an aerosol sampling train which allowed a known quantity of the effluent streams to be sampled. Depending on the position, a 15 to 25 l/min sample is extracted from the duct, immediately diluted and transferred to a sampling/aging chamber. Transmission and scanning electron microscope samples, two types of cascade impactor samples, vapor-phase and particulate-phase organic samples, spiral duct aerosol centrifuge samples, optical size measurements and filter samples were obtained. Samples are undergoing physical, chemical and biological tests to help establish human health risk estimates for fluidized bed coal combustion and to provide information for use in design and evaluation of control technologies

Effects of the updated national emission regulation in China on circulating fluidized bed boilers and the solutions to meet them.

Science.gov (United States)

Li, Jingji; Yang, Hairui; Wu, Yuxin; Lv, Junfu; Yue, Guangxi

2013-06-18

The advantage of circulating fluidized bed (CFB) boilers in China is their ability to utilize low rank coal with low cost emission control. However, the new National Emission Regulation (NER) issued in early 2012 brings much more stringent challenges on the CFB industries, which also causes much attention from other countries. Based on the principle of a CFB boiler and previous operating experience, it is possible for the CFB boilers to meet the new NER and maintain the advantage of low cost emission control, while, more influences should be considered in their design and operation. To meet the requirement of the new NER, the fly ash collector should adopt a bag house or combination of electrostatic precipitator and bag filter to ensure dust emissions of less than 30 mg · Nm(-3). For SO2 emission control, the bed temperature should be strictly lower than 900 °C to maintain high reactivity and pores. The limestone particle size distribution should be ranged within a special scope to optimize the residence time and gas-solid reaction. At the same time, the injecting point should be optimized to ensure fast contact of lime with oxygen. In such conditions, the desulfurization efficiency could be increased more than 90%. For lower sulfur content fuels (emissions lower than that of the new NER, 100 mg · Nm(-3). For fuels with sulfur content higher than 1.5%, some simplified systems for flue gas desulfurization, such as flash dryer absorber (FDA), are needed. And the NOx emissions of a CFB can be controlled to less than 100 mg · Nm(-3) without any equipment at a bed temperature lower than 900 °C for fuels with low volatiles content (emission of CFB is very low for the new NER due to its innate property.

Powder stickiness in milk drying: uncertainty and sensitivity analysis for process understanding

DEFF Research Database (Denmark)

Ferrari, Adrián; Gutiérrez, Soledad; Sin, Gürkan

2017-01-01

A powder stickiness model based in the glass transition temperature (Gordon – Taylor equations) was built for a production scale milk drying process (including a spray chamber, and internal/external fluid beds). To help process understanding, the model was subjected to sensitivity analysis (SA...... for nonlinear error propagation was selected as the main UA approach. SA results show an important local sensitivity on the spray dryer, but at the end of the internal fluid bed (critical point for stickiness) minor local sensitivities were observed. Feed concentrate moisture was found as the input with major...... global sensitivity on the glass transition temperature at the critical point, so it could represent a key variable for helping on stickiness control. UA results show the major model predictions uncertainty on the spray dryer, but it does not represent a stickiness issue since the product...

Decreased bed rest post-percutaneous coronary intervention with a 7-French arterial sheath and its effects on vascular complications.

Science.gov (United States)

Wentworth, Laura J; Bechtum, Elizabeth L; Hoffman, Jessica G; Kramer, Robert R; Bartel, David C; Slusser, Joshua P; Tilbury, Ralph Thomas

2018-01-01

To compare the incidence of femoral access puncture site complications in the control group, who underwent 6 hr of bed rest, with patients in the case group, who underwent 4 hr of bed rest. The ideal bed rest length after percutaneous coronary intervention with a 7-French arterial sheath has been investigated by nursing practice. However, in this larger-sheath-size group, best practices have not been determined, and bed rest time continues to vary markedly among institutions. Retrospective study. Data were retrieved from the National Cardiovascular Data Registry and electronic health records in this retrospective study. Sample size was 401 patients: 152 case patients with 4-hr bed rest and 249 controls with 6-hr bed rest. Case group data were obtained from 20 May 2013-31 December 2014; and control group data, 15 June 2011-20 May 2013. National Cardiovascular Data Registry event rates were generally low in both groups: Only three patients in each group had a bleeding event within 72 hr (2% vs. 1%) and no patient and only two controls had arteriovenous fistula (0% vs. 1%). Complications documented in the electronic health records with institutional femoral access puncture site complication definitions identified bleeding at the access site in eight case patients (5%) and nine controls (4%). Haematoma at the access site occurred in 21 case patients (14%) and 25 controls (10%). The practice change of decreasing bed rest from 6-4 hr for patients with 7-French arterial sheaths post-percutaneous coronary intervention was associated with no significant change in femoral access puncture site complications in either National Cardiovascular Data Registry data or institutional electronic health records data. This introduces expanded evidence of safety in decreasing bed rest length in larger (7-French) arterial sheaths post-percutaneous coronary intervention. © 2017 John Wiley & Sons Ltd.

Management bedding : vrijloopstal met composterende bedding van houtsnippers

NARCIS (Netherlands)

Boer, de H.C.; Wiersma, M.; Galama, P.J.; Szanto, G.L.

2015-01-01

In de vrijloopstal liggen de koeien meestal op een organische bedding en scheiden daar mest (feces en urine) uit. Om de bedding voldoende droog en schoon te houden wordt er regelmatig nieuw strooisel aangevoerd en wordt de toplaag bewerkt. Op basis van onderzoek- en praktijkervaringen tot nu toe

Determinación del coeficiente global de transferencia de calor en secaderos rotativos de cáscara de limón Determination of global heat transfer coefficient in lemon peel rotary dryers

Directory of Open Access Journals (Sweden)

Marcos A. Golato

2005-12-01

Full Text Available En la bibliografía consultada no se encontraron trabajos de secado de cáscara de limón en secaderos rotativos. Se realizaron ensayos de medición en secaderos rotativos de cáscara de limón en una instalación agroindustrial del noroeste argentino. Se desarrolló un modelo matemático semiempírico mediante la resolución de los balances de materia y energía. Se obtuvo una correlación estadística para la predicción de los coeficientes globales volumétricos de transferencia de calor aparentes para secaderos rotativos de cáscara de limón.No papers on lemon peel drying in rotary dryers were actually found in the sources consulted. Measurement tests were carried out in the assessment of rotary dryer systems used to dehydrate lemon peel in an agroindustrial plant of Northwestern Argentina. A semiempirical mathematic model was developed solving mass and energy balances. A statistical correlation for predicting global heat transfer coefficient in rotary dryer lemon peel dehydration was obtained.

Effect of bed particles to combustion of gases in fluidized bed

Energy Technology Data Exchange (ETDEWEB)

Raiko, R.; Wallen, V.; Etelaeaho, R.; Correia, S. [Tampere Univ. of Technology (Finland). Energy and Process Engineering

1997-10-01

The objective of this project was to obtain experimental data on effects of sand particles to the combustion of gases. The effect of the surface area of the particles was tested using different sized particles. The fluidized bed reactor used in these experiments was a stainless-steel tube with an internal diameter of 42 mm surrounded by an electric heater. The test rig was built in the Laboratory of Energy and Process Engineering at Tampere University of Technology. In order to elucidate the possible changes of particle surface, microscopic and porosimetric studies were conducted with both fresh bed particles and used bed particles. These measurements indicate that carbon monoxide significantly reacts with oxygen in the particulate or emulsion phase of a fluidized bed, if the residence time is long enough. The reaction rate depends mainly on temperature, air coefficient, residence time and particle size of the solids. It seems that the combustion enhances if the average particle size increases. Whether this is caused by increased free path length or reduced specific surface area of the bed is yet unknown. The first might be more probable cause because the majority of reactions often took place in the freeboard right above the bed. It was clear that the bed hindered proper combustion in several cases. (orig.)

Electron-impact excitation and recombination of molecular cations in edge fusion plasma: application to H2+and BeD+

Science.gov (United States)

Pop, Nicolina; Iacob, Felix; Mezei, Zsolt; Motapon, Ousmanou; Niyonzima, Sebastien; Schneider, Ioan

2017-10-01

Dissociative recombination, ro-vibrational excitation and dissociative excitation of molecular cations with electrons are major elementary process in the kinetics and in the energy balance of astrophysically-relevant ionized media (supernovae, interstellar molecular clouds, planetary ionospheres, early Universe), in edge fusion and in many other cold media of technological interest. For the fusion plasma edge, extensive cross sections and rate coefficients have been produced for reactions induced on HD+, H2+ and BeD+ using the Multichannel Quantum Defect Theory (MQDT). Our calculations resulted in good agreement with the CRYRING (Stockholm) and TSR (Heidelberg) magnetic storage ring results, and our approach is permanently improved in order to face the new generation of electrostatic storage rings, as CSR (Heidelberg) and DESIREE (Stockholm). Member of APS Reciprocal Society: European Physics Society.

Bed retained products in swept fixed bed (SFB) coal hydropyrolysis

Energy Technology Data Exchange (ETDEWEB)

Mastral, A.M.; Perez-Surio, M.J. [CSIC, Zaragosa (Spain). Inst. de Carboquimica

1997-12-31

The hydropyrolysis of a low rank coal in a swept fixed bed (SFB) reactor is carried out by fixing the hydrogen pressure (40 kg/cm{sup 2}), the hydrogen flow (2 l/min) and the residence time (10 min) at increasing temperatures (400 C, 500 C and 600 C) and coal bed heights (h, 1.5h, 2h, 2.5h and 3h). It is shown that the percentages of tars and char directly depend on the coal bed height and that there is not only a quantitative dependence, but also the height of the coal bed is very important and plays a relevant role on the nature of the conversion products. (orig.)

In-bed accountability of tritium in production scale metal hydride storage beds

International Nuclear Information System (INIS)

Klein, J.E.

1995-01-01

An ''in-bed accountability'' (IBA) flowing gas calorimetric measurement method has been developed and implemented to eliminate the need to remove tritium from production scale metal hydride storage beds for inventory measurement purposes. Six-point tritium IBA calibration curves have been completed for two, 390 gram tritium metal hydride storage beds. The calibration curves for the two tritium beds are similar to those obtained from the ''cold'' test program. Tritium inventory errors at the 95 percent confidence level ranged from ± 7.3 to 8.6 grams for the cold test results compared to ± 4.2 to 7.5 grams obtained for the two tritium calibrated beds

Biomass equipments. Dryers. Drying, crushing, agglomeration of agro-industrial products; Materiels pour la biomasse. Les secheurs, sechage, broyage, agglomeration de produits agro-industriels

Energy Technology Data Exchange (ETDEWEB)

Deur, O. [Promill (France)

1997-12-31

This paper describes the French Promill Company activity in the design and manufacturing of complete drying-crushing-agglomerating units for agro-industrial products (pulp of beet, lucerne, etc..). The paper focusses on the thermal and mechanical efficiency of the high temperature dryer and on the pulp granulating squeezer. (J.S.)

Performance of a Big Scale Green House Type Dryer for Coffee Drying Process

Directory of Open Access Journals (Sweden)

Sukrisno Widyotomo

2014-12-01

Full Text Available Dying is one of important steps in coffee processing to produce good quality. Greenhouse is one of artificial drying alternatives that potential for coffee drying method cause of cleans environmental friendly, renewable energy sources and chippers. Indonesian Coffee and Cocoa Research Institute has developed and testing a big scale greenhouse type dryer for fresh coffee cherries and wet parchment coffee drying process. Greenhouse has 24 m length, 18 m width, also 3 m high of the front side and 2 m high of the rear side. The maximum capacity of greenhouse is 40 tons fresh coffee cherries. Fiber Reinforced Plastic (FRP used as greenhouse roof that combined with I and C profile of steel. Fresh coffee cherries and wet parchment coffee from Robusta variety use as main materials in this research. The treatment of this research was 30 kg/m2, 60 kg/m2 and 90 kg/m2 for coffee density. String process has done by manual, two times a day in the morning and in the afternoon. As control, fresh coffee cherries and wet parchment coffee has dried by fully sun drying method. The result showed that a big scale greenhouse has heat drying efficiency between 29.9-58.2% depend on type and density of coffee treatments. On the full sunny day, greenhouse has produced maximum drying air temperature up to 52oC. In radiation cumulative level 4-5 kW-jam/m2 per day, 12.9-38.8 tons fresh coffee cherries or wet parchment coffee with 58-64% moisture content can be dried to 12% moisture content for 6 up to 14 days drying process. Slowly drying mechanism can be avoided negative effect to degradation of quality precursor compound. Capacity of the dryer can be raise and fungi can be reduce with application of controllable mechanical stirring in the greenhouse. Keywords: greenhouse, coffee, drying, quality

Thermal Analysis of Fluidized Bed and Fixed Bed Latent Heat Thermal Storage System

Science.gov (United States)

Beemkumar, N.; Karthikeyan, A.; Shiva Keshava Reddy, Kota; Rajesh, Kona; Anderson, A.

2017-05-01

Thermal energy storage technology is essential because its stores available energy at low cost. Objective of the work is to store the thermal energy in a most efficient method. This work is deal with thermal analysis of fluidized bed and fixed bed latent heat thermal storage (LHTS) system with different encapsulation materials (aluminium, brass and copper). D-Mannitol has been used as phase change material (PCM). Encapsulation material which is in orbicular shape with 4 inch diameter and 2 mm thickness orbicular shaped product is used. Therminol-66 is used as a heat transfer fluid (HTF). Arrangement of encapsulation material is done in two ways namely fluidized bed and fixed bed thermal storage system. Comparison was made between the performance of fixed bed and fluidized bed with different encapsulation material. It is observed that from the economical point of view aluminium in fluidized bed LHTS System has highest efficiency than copper and brass. The thermal energy storage system can be analyzed with fixed bed by varying mass flow rate of oil paves a way to find effective heat energy transfer.

Combustion and regulations. Impacts of new regulations on medium-power thermal equipment (boilers, engines, turbines, dryers and furnaces); Combustion et reglementation. Incidences des nouvelles reglementations sur les equipements thermiques de moyenne puissance (chaudieres, moteurs, turbines, secheurs et fours)

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-12-31

This conference is composed of 20 papers on the influence of French and European new pollution regulations on medium size thermal equipment such as boilers, engines, turbines, dryers and furnaces. It is discussed what is going to change with new regulations, how they will apply to existing plants, what will be the impact on future equipment costs. The evolution of energy suppliers and equipment manufacturers facing these new regulations is also examined: fuel substitution, improvements in turbines and engines with water injection and special chambers, diesel engine control, lean mixtures and electronic control for gas engines... Means for reducing SOx, NOx and ash emission levels in boilers are also examined

Bed care for patients in palliative settings: considering risks to caregivers and bed surfaces.

Science.gov (United States)

Fragala, Guy

2015-02-01

Ensuring patients are comfortable in bed is key to effective palliative care, but when moving and positioning patients in bed, health professionals face an occupational risk of injury. The turning and positioning (TAP) system is a new method of moving patients in bed, that evidence has shown to reduce the risk of injury to caregivers. Providing the correct bed surface is another aspect of bed care essential to the comfort of the palliative patient, and to aid wound prevention and treatment. It is important to take a patient-centred approach when considering the most appropriate bed surface patients. This article provides an overview and discussion of these two aspects of bed care for palliative patients.

Fluid bed porosity equation for an inverse fluidized bed bioreactor with particles growing biofilm

International Nuclear Information System (INIS)

Campos-Diaz, K. E.; Limas-Ballesteros, R.

2009-01-01

Fluid Bed Bioreactor performance is strongly affected by bed void fraction or bed porosity fluctuations. Particle size enlargement due to biofilm growth is an important factor that is involved in these variations and until now there are no mathematical equations that consider biofilm growth. In this work a mathematical equation is proposed to calculate bed void fraction in an inverse fluid bed bioreactor. (Author)

Evaluation and comparing of natural and forced solar dryer for mint drying in Khuzestan province

Directory of Open Access Journals (Sweden)

J Habibi Asl

2017-05-01

Research Center during the years 2011-2013. Materials and Methods In this research an indirect cabinet solar dryer with three trays and grooved collector was constructed. To improve air convection, a chimney was mounted above the dryer. The dryer performance was evaluated by drying mint leaves in three levels of mass density of 2, 3, and 4 kg m-2 at two drying manners of natural and forced convection and compared with drying mint leaves in shade as the traditional method. Results and Discussion The results showed that total drying time required in different solar drier treatments was 3.5 to 15 h, while it was about 5 days in traditional method. Drying time in upper trays was more as the air flow decreased due to increase in mass density. Mean required drying time in forced convection was 29.7% less than that of natural convection. Maximum essences with 0.80% and 0.76% were belonged to "natural convection and 3kg m-2 mass density" and "forced convection and 4 kg m-2 mass density" treatments respectively, while minimum one with 0.30% was for "forced convection and 2 kg m-2 mass density" treatment. Also, the highest and lowest chlorophyll content with 8.51 and 4.18 mg ml-1 were measured in "natural convection and 3 kg m-2 mass density" and "forced convection and 4 kg m-2 mass density" treatments respectively. According to obtained results, 3 and 4 kg m-2 mass density can be suggested for natural and forced convection solar drying of mint leaves in Khuzestan condition respectively. Conclusions In order to reduce vegetable losses and increase Khuzestan vegetable producers income, indirect cabinet solar dryer for drying mint leaves in winter season, could be an appropriate option. For natural and forced convection drying methods, mass density of 3 and 4 kg m-2 is recommended respectively.

Bed agglomeration risk related to combustion of cultivated fuels (wheat straw, red canary grass, industrial hemp) in commercial bed materials; Baeddagglomereringsrisk vid foerbraenning av odlade braenslen (hampa, roerflen, halm) i kommersiella baeddmaterial

Energy Technology Data Exchange (ETDEWEB)

Erhardsson, Thomas; Oehman, Marcus; Geyter, Sigrid de; Oehrstroem, Anna

2006-12-15

The market of forest products is expanding and thus resulting in more expensive biomass fuels. Therefore research within the combustion industry for alternative fuels is needed, for example cultivated fuels. Combustion and gasification research on these cultivated fuels are limited. The objectives of this work was to increase the general knowledge of silicon rich cultivated fuels by study the agglomeration characteristics for wheat straw, reed canary grass and industrial hemp in combination with commercial bed materials. Controlled fluidized bed agglomeration tests was conducted in a 5 kW, bench-scale, bubbling fluidized bed reactor. The tendencies of agglomeration were determined with the three cultivated fuels in combination with various minerals present in natural sand (quarts, plagioclase and potassium feldspar) and an alternative bed material (olivine). During the experiments bed samples and formed agglomerates were collected for further analyses with a scanning electron microscope (SEM) and with X-ray microanalysis (EDS). Wheat straw had the highest agglomeration tendency of the studied fuels followed by reed canary grass and industrial hemp. No significant layer formation was found around the different bed particles. Instead, the ash forming matter were found as individual ash sticky (partial melted) particles in the bed. The bed material mineralogical composition had no influence of the agglomeration process because of the non layer formation propensities of the used silicon rich fuels.

Pebble-bed reactor

International Nuclear Information System (INIS)

Lohnert, G.; Mueller-Frank, U.; Heil, J.

1976-01-01

A pebble-bed nuclear reactor of large power rating comprises a container having a funnel-shaped bottom forming a pebble run-out having a centrally positioned outlet. A bed of downwardly-flowing substantially spherical nuclear fuel pebbles is positioned in the container and forms a reactive nuclear core maintained by feeding unused pebbles to the bed's top surface while used or burned-out pebbles run out and discharge through the outlet. A substantially conical body with its apex pointing upwardly and its periphery spaced from the periphery of the container spreads the bottom of the bed outwardly to provide an annular flow down the funnel-shaped bottom forming the runout, to the discharge outlet. This provides a largely constant downward velocity of the spheres throughout the diameter of the bed throughout a substantial portion of the down travel, so that all spheres reach about the same burned-out condition when they leave the core, after a single pass through the core area

The Safety of Hospital Beds

Science.gov (United States)

Gervais, Pierre; Pooler, Charlotte; Merryweather, Andrew; Doig, Alexa K.; Bloswick, Donald

2015-01-01

To explore the safety of the standard and the low hospital bed, we report on a microanalysis of 15 patients’ ability to ingress, move about the bed, and egress. The 15 participants were purposefully selected with various disabilities. Bed conditions were randomized with side rails up or down and one low bed with side rails down. We explored the patients’ use of the side rails, bed height, ability to lift their legs onto the mattress, and ability to turn, egress, and walk back to the chair. The standard bed was too high for some participants, both for ingress and egress. Side rails were used by most participants when entering, turning in bed, and exiting. We recommend that side rails be reconsidered as a means to facilitate in-bed movement, ingress, and egress. Furthermore, single deck height settings for all patients are not optimal. Low beds as a safety measure must be re-evaluated. PMID:28462302

Fluid-bed combustion

Energy Technology Data Exchange (ETDEWEB)

Hunt, G.; Schoebotham, N.

1981-02-01

In Energy Equipment Company's two-stage fluidized bed system, partial combustion in a fluidized bed is followed by burn-off of the generated gases above the bed. The system can be retrofitted to existing boilers, and can burn small, high ash coal efficiently. It has advantages when used as a hot gas generator for process drying. Tests on a boiler at a Cadbury Schweppes plant are reported.

Apparatus for controlling fluidized beds

Science.gov (United States)

Rehmat, A.G.; Patel, J.G.

1987-05-12

An apparatus and process are disclosed for control and maintenance of fluidized beds under non-steady state conditions. An ash removal conduit is provided for removing solid particulates from a fluidized bed separate from an ash discharge conduit in the lower portion of the grate supporting such a bed. The apparatus and process of this invention is particularly suitable for use in ash agglomerating fluidized beds and provides control of the fluidized bed before ash agglomeration is initiated and during upset conditions resulting in stable, sinter-free fluidized bed maintenance. 2 figs.

Definition of postlumpectomy tumor bed for radiotherapy boost field planning: CT versus surgical clips

International Nuclear Information System (INIS)

Goldberg, Hadassah; Prosnitz, Robert G.; Olson, John A.; Marks, Lawrence B.

2005-01-01

Purpose: To compare the location and extent of the tumor bed as defined by surgical clips and computed tomography (CT) scans, after lumpectomy, for electron boost planning as part of breast radiotherapy. Methods and Materials: Planning CT images of 31 operated breasts in 30 patients who underwent lumpectomy were reviewed. One or more clips were placed in the lumpectomy cavity. Serial CT images were used to measure the depth and transverse and longitudinal dimensions. The area and geometric center of the tumor bed were defined by the clips and CT. Results: The CT and clip measurements were identical for the maximal tumor depth in 27 of 30 patients. The CT bed extended beyond the clips by 0-7 mm medially in the transverse/longitudinal extent (multiclip patients). The median distance between the geometric centers in the coronal plane for the tumor bed center was larger for patients with single clips than for those with multiple clips (p 2 . The CT bed was more readily visible in patients with a shorter interval between surgery and radiotherapy. Conclusion: The maximal depth of the tumor bed was similar using the two methods. The extent and centers of the clip-and CT-determined beds differed significantly. This may indicate an underestimation of the tumor bed as defined by clips only and justifies integration of CT information in boost field planning

Experimental study of flow field characteristics on bed configurations in the pebble bed reactor

International Nuclear Information System (INIS)

Jia, Xinlong; Gui, Nan; Yang, Xingtuan; Tu, Jiyuan; Jia, Haijun; Jiang, Shengyao

2017-01-01

Highlights: • PTV study of flow fields of pebble bed reactor with different configurations are carried out. • Some criteria are proposed to quantify vertical velocity field and flow uniformity. • The effect of different pebble bed configurations is also compared by the proposed criteria. • The displacement thickness is used analogically to analyze flow field characteristics. • The effect of mass flow variation in the stagnated region of the funnel flow is measured. - Abstract: The flow field characteristics are of fundamental importance in the design work of the pebble bed high temperature gas cooled reactor (HTGR). The different effects of bed configurations on the flow characteristics of pebble bed are studied through the PTV (Particle Tracking Velocimetry) experiment. Some criteria, e.g. flow uniformity (σ) and mass flow level (α), are proposed to estimate vertical velocity field and compare the bed configurations. The distribution of the Δθ (angle difference between the individual particle velocity and the velocity vector sum of all particles) is also used to estimate the resultant motion consistency level. Moreover, for each bed configuration, the thickness of displacement is analyzed to measure the effect of the funnel flow zone based on the boundary layer theory. Detailed information shows the quantified characteristics of bed configuration effects on flow uniformity and other characteristics; and the sequence of levels of each estimation criterion is obtained for all bed configurations. In addition, a good design of the pebble bed configuration is suggested and these estimation criteria can be also applied and adopted in testing other geometry designs of pebble bed.

Bed diameter effects and incipient slugging in gas fluidized beds

International Nuclear Information System (INIS)

Agarwal, P.K.

1986-01-01

The coalescence and growth of bubble swarms formed at the distributor of a fluidized bed gives rise to lateral as well as vertical distributions of bubble properties. However, existing models employ average bubble properties obtained largely from semi-empirical considerations. In a recent Paper, the author developed a bubble growth model based on a population balance approach. Analytical expressions were derived for the bubble characteristic distributions and averages. However, the model, developed for unconstrained growth, did not take into account the effect of the bed diameter and the possibility of slugging. In this Paper, the model is extended to take these aspects into account. A slugging criterion is also developed which is expected to be valid for the regime where incipient slugging depends on the bed height as well as the region where bed height does not significantly affect minimum slugging conditions

Effect of bed configuration on pebble flow uniformity and stagnation in the pebble bed reactor

International Nuclear Information System (INIS)

Gui, Nan; Yang, Xingtuan; Tu, Jiyuan; Jiang, Shengyao

2014-01-01

Highlights: • Pebble flow uniformity and stagnation characteristics are very important for HTR-PM. • Arc- and brachistochrone-shaped configuration effects are studied by DEM simulation. • Best bed configurations with uniform flow and no stagnated pebbles are suggested. • Detailed quantified characteristics of bed configuration effects are shown for explanation. - Abstract: Pebble flow uniformity and stagnation characteristics are very important for the design of pebble bed high temperature gas-cooled reactor. Pebble flows inside some specifically designed contraction configurations of pebble bed are studied by discrete element method. The results show the characteristics of stagnation rates, recycling rates, radial distribution of pebble velocity and residence time. It is demonstrated clearly that the bed with a brachistochrone-shaped configuration achieves optimum levels of flow uniformity and recycling rate concentration, and almost no pebbles are stagnated in the bed. Moreover, the optimum choice among the arc-shaped bed configurations is demonstrated too. Detailed information shows the quantified characteristics of bed configuration effects on flow uniformity. In addition, a good design of the pebble bed configuration is suggested

Visualization of bed material movement in a simulated fluidized bed heat exchanger by neutron radiography

International Nuclear Information System (INIS)

Umekawa, Hisashi; Ozawa, Mamoru; Takenaka, Nobuyuki; Matsubayashi, Masahito

1999-01-01

The bulk movement of fluidized bed material was visualized by neutron radiography by introducing tracers into the bed materials. The simulated fluidized bed consisted of aluminum plates, and the bed material was sand of 99.7% SiO 2 (mean diameter: 0.218 mm, density: 2555 kg/m 3 ). Both materials were almost transparent to neutrons. Then the sand was colored by the contamination of the sand coated by CdSO 4 . Tracer particles of about 2 mm diameter were made by the B 4 C, bonded by the vinyl resin. The tracer was about ten times as large as the particle of fluidized bed material, but the traceability was enough to observe the bed-material bulk movement owing to the large effective viscosity of the fluidized bed. The visualized images indicated that the bubbles and/or wakes were important mechanism of the behavior of the fluidized bed movement

Method and apparatus for a combination moving bed thermal treatment reactor and moving bed filter

Energy Technology Data Exchange (ETDEWEB)

Badger, Phillip C.; Dunn, Jr., Kenneth J.

2015-09-01

A moving bed gasification/thermal treatment reactor includes a geometry in which moving bed reactor particles serve as both a moving bed filter and a heat carrier to provide thermal energy for thermal treatment reactions, such that the moving bed filter and the heat carrier are one and the same to remove solid particulates or droplets generated by thermal treatment processes or injected into the moving bed filter from other sources.

Unique concept results in 67% energy saving of dryer. Successful use of a NH3 heat pump for a McCain fried potato dryer; Uniek concept leidt tot een energiebesparing van 67% op de droger. NH3-warmtepomp succesvol toegepast op frietdroger van McCain

Energy Technology Data Exchange (ETDEWEB)

De Leeuw, M. [De Kleijn Energie Consulting, Druten (Netherlands)

2013-07-15

French fries producer McCain Foods installed in the summer of 2012 an ammonia heat pump for a fried potato dryer in Lelystad, Netherlands. After six months it appears that the installation operates without problems and with a very high efficiency [Dutch] Frietproducent McCain Foods installeerde in de zomer van 2012 een warmtepomp op de frietdroger in Lelystad. Na een half jaar kan geconstateerd worden dat de installatie zonder problemen en met een zeer hoog rendement draait.

Fluidised bed combustion system

International Nuclear Information System (INIS)

McKenzie, E.C.

1976-01-01

Fluidized bed combustion systems that facilitates the maintenance of the depth of the bed are described. A discharge pipe projects upwardly into the bed so that bed material can flow into its upper end and escape downwardly. The end of the pipe is surrounded by an enclosure and air is discharged into the enclosure so that material will enter the pipe from within the enclosure and have been cooled in the enclosure by the air discharged into it. The walls of the enclosure may themselves be cooled

WTP Pretreatment Facility Potential Design Deficiencies--Sliding Bed and Sliding Bed Erosion Assessment

Energy Technology Data Exchange (ETDEWEB)

Hansen, E. K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-05-06

This assessment is based on readily available literature and discusses both Newtonian and non-Newtonian slurries with respect to sliding beds and erosion due to sliding beds. This report does not quantify the size of the sliding beds or erosion rates due to sliding beds, but only assesses if they could be present. This assessment addresses process pipelines in the Pretreatment (PT) facility and the high level waste (HLW) transfer lines leaving the PT facility to the HLW vitrification facility concentrate receipt vessel.

WTP Pretreatment Facility Potential Design Deficiencies--Sliding Bed and Sliding Bed Erosion Assessment

International Nuclear Information System (INIS)

Hansen, E. K.

2015-01-01

This assessment is based on readily available literature and discusses both Newtonian and non-Newtonian slurries with respect to sliding beds and erosion due to sliding beds. This report does not quantify the size of the sliding beds or erosion rates due to sliding beds, but only assesses if they could be present. This assessment addresses process pipelines in the Pretreatment (PT) facility and the high level waste (HLW) transfer lines leaving the PT facility to the HLW vitrification facility concentrate receipt vessel.

Thin-layer drying of tomato (Lycopersicum esculentum Mill. cv. Rio Grande) slices in a convective hot air dryer

Energy Technology Data Exchange (ETDEWEB)

Demiray, Engin; Tulek, Yahya [Pamukkale University, Engineering Faculty, Department of Food Engineering, Kinikli, Denizli (Turkey)

2012-05-15

The effects of different drying temperatures on the drying kinetics of tomato slices were investigated using a cabinet-type dryer. The experimental drying data were fitted best to the to the Page and Modified Page models apart from other theoretical models to predict the drying kinetics. The effective moisture diffusivities varied from 1.015 x 10{sup -9} to 2.650 x 10{sup -9} m {sup 2} s {sup -1}over the temperature range studied, and activation energy was 22.981 kJ mol {sup -1}. (orig.)

Controlling in situ crystallization of pharmaceutical particles within the spray dryer.

Science.gov (United States)

Woo, Meng Wai; Lee, May Ginn; Shakiba, Soroush; Mansouri, Shahnaz

2017-11-01

Simultaneous solidification and in situ crystallization (or partial crystallization) of droplets within the drying chamber are commonly encountered in the spray drying of pharmaceuticals. The crystallinity developed will determine the functionality of the powder and its stability during storage. This review discusses strategies that can be used to control the in situ crystallization process. Areas covered: The premise of the strategies discussed focuses on the manipulation of the droplet drying rate relative to the timescale of crystallization. This can be undertaken by the control of the spray drying operation, by the use of volatile materials and by the inclusion of additives. Several predictive approaches for in situ crystallization control and new spray dryer configuration strategies are further discussed. Expert opinion: Most reports, hitherto, have focused on the crystallinity of the spray dried material or the development of crystallinity during storage. More mechanistic understanding of the in situ crystallization process during spray drying is required to guide product formulation trials. The key challenge will be in adapting the mechanistic approach to the myriad possible formulations in the pharmaceutical industry.

Bacillus cereus in free-stall bedding.

Science.gov (United States)

Magnusson, M; Svensson, B; Kolstrup, C; Christiansson, A

2007-12-01

To increase the understanding of how different factors affect the bacterial growth in deep sawdust beds for dairy cattle, the microbiological status of Bacillus cereus and coliforms in deep sawdust-bedded free stalls was investigated over two 14-d periods on one farm. High counts of B. cereus and coliforms were found in the entire beds. On average, 4.1 log(10) B. cereus spores, 5.5 log(10) B. cereus, and 6.7 log(10) coliforms per gram of bedding could be found in the upper layers of the sawdust likely to be in contact with the cows' udders. The highest counts of B. cereus spores, B. cereus, and coliforms were found in the bedding before fresh bedding was added, and the lowest immediately afterwards. Different factors of importance for the growth of B. cereus in the bedding material were explored in laboratory tests. These were found to be the type of bedding, pH, and the type and availability of nutrients. Alternative bedding material such as peat and mixtures of peat and sawdust inhibited the bacterial growth of B. cereus. The extent of growth of B. cereus in the sawdust was increased in a dose-dependent manner by the availability of feces. Urine added to different bedding material raised the pH and also led to bacterial growth of B. cereus in the peat. In sawdust, a dry matter content greater than 70% was needed to lower the water activity to 0.95, which is needed to inhibit the growth of B. cereus. In an attempt to reduce the bacterial growth of B. cereus and coliforms in deep sawdust beds on the farm, the effect of giving bedding daily or a full replacement of the beds was studied. The spore count of B. cereus in the back part of the free stalls before fresh bedding was added was 0.9 log units lower in stalls given daily bedding than in stalls given bedding twice weekly. No effect on coliform counts was found. Replacement of the entire sawdust bedding had an effect for a short period, but by 1 to 2 mo after replacement, the counts of B. cereus spores in the

Astronomical cycle origin of bedded chert: A middle Triassic bedded chert sequence, Inuyama, Japan

Science.gov (United States)

Ikeda, Masayuki; Tada, Ryuji; Sakuma, Hironobu

2010-09-01

Astronomical forcing is one of the main drivers of climate change, and astronomical cyclicity recorded in sediments provides a clue to understand the dynamics of the global climate system. Bedded cherts consist of rhythmic alternations of chert and shale beds. Although previous studies have hypothesized that the origin of bedded chert is related to astronomical cycles (e.g. Fischer, 1976; Hori et al., 1993), conclusive proof remains elusive. To explore this possibility, we established a continuous, high-resolution lithostratigraphy of middle Triassic bedded chert in Central Japan. The average duration of each chert-shale couplet is 20 kyr, similar to that of the precession cycle. Spectral analysis of a bed number series of thickness variations in chert beds was performed assuming that each chert-shale couplet represents a 20-kyr precession cycle. The results reveal cycles involving approximately 200, 20, 5, and 2-3 beds, corresponding to periodicities of approximately 4000, 400, 100, and 40-60 kyr, respectively. By further assuming that the 20-bed cycle represents a 405-kyr eccentricity cycle of constant and stable periodicity, we converted the bed number series to a time series. Spectral analysis of the time series revealed distinct periodicities of 3600, 117, 97, and 38 kyr, in addition to 405 kyr. Besides 3600 kyr, these periodicities agree well with the 120, 95, and 37 kyr periodicities for eccentricity cycles and the obliquity cycle during the Triassic. Moreover, we detected amplitude modulation of the approximately 100-kyr cycle of thickness variations in chert beds with a 405-kyr periodicity, which may correspond to amplitude modulation of 100-kyr climatic precession cycle with the 405-kyr periodicity. The approximately 3600-kyr periodicity described above and 1800-kyr periodicity manifested as the amplitude modulation of the 405-kyr cycle are correlated to present-day long-term eccentricity cycles of 2400 and 4800 kyr evolved by chaotic behavior of solar

Woodpecker-inspired shock isolation by microgranular bed

Energy Technology Data Exchange (ETDEWEB)

Yoon, Sang-Hee [Department of Mechanical Engineering, University of California, Berkeley, CA 94720 (United States); Roh, Jin-Eep; Kim, Ki Lyug, E-mail: shyoon@me.berkeley.ed [Agency for Defense Development, Yuseong PO Box 35, Daejeon 305-600 (Korea, Republic of)

2009-02-07

This paper presents a woodpecker-inspired shock isolation (SI) using a microgranular bed to protect micromachined electronic devices (MEDs) for high-g military applications where mechanical excitations reach up to tens of thousands of gs and several hundreds of kHz. The shock isolating phenomenon in the microgranular bed within a metal housing, biomimetically inspired from a spongy bone within a skull of the woodpecker, controls unwanted high-frequency mechanical excitations so that their adverse effects on the embedded MEDs are kept within acceptable limit. The microgranular bed composed of close-packed microglass beads reduces the mechanical excitations transmitted to the MEDs through kinetic energy absorption. Two kinds of tests, a laboratory test and a 60 mm air-gun test, have been made. The laboratory test using a vibration exciter up to 25 kHz has demonstrated that the cut-off frequency (2.2-15.8 kHz) and roll-off steepness (-155.0 to -78.7 dB decade{sup -1}) are inversely proportional to the diameter of the close-packed microglass beads (68-875 {mu}m), whereas the vibration absorptivity (0.23-0.87) is proportional. The 60 mm air-gun test under high-g environments of up to 60 000 g has verified that the woodpecker-inspired SI is superior in improving the shock survivability of the MEDs to the conventional one using hard resin.

Study of the energy efficiency of coffee drying with different revolving combinations time; Estudo da eficiencia energetica de secagem de cafe com diferentes combinacoes de tempo de revolvimento

Energy Technology Data Exchange (ETDEWEB)

Greco, Marcelo; Campos, Alessandro Torres [Universidade Estadual do Oeste do Parana (UNIOESTE), Marechal Candido Rondon, PR (Brazil). Grupo de Pesquisas em Ambiencia do Oeste do Parana (GPEA)], e-mail: greco.b@bol.com.br; Molin, Roberto Natal dal; Oliveira, Marcos C. Oliveira; Camara, Roberto J; Klein, Jeferson [Universidade Estadual do Oeste do Parana (UNIOESTE), Marechal Candido Rondon, PR (Brazil); Siqueira Filho, Roberto [Universidade Estadual do Oeste do Parana (UNIOESTE), Marechal Candido Rondon, PR (Brazil); Ministerio da Agricultura, Pecuaria e Abastecimento (MAPA), Brasilia, DF (Brazil)

2004-07-01

This work objected to evaluate the energy efficiency in the coffee (Coffea arabica L.) drying with different combinations of revolving time in a fixed bed dryer. The experiment was developed the months of June and July of 2003, in a farm located in the municipal district of Jesuitas-Parana State, Brazil. The product quality evaluations were accomplished in the Consolata Agricultural Cooperative Ltda. (COPACOL). The grains parameters were evaluated at the Seeds Technology Laboratory, at the UNIOESTE Campus Marechal Candido Rondon. A fixed bed model dryer was used, with a metallic drying chamber, of cylindrical format, with an adapted grain revolving system, keeping the air temperature at 75 deg C. It was observed that the energy consumed for burning the fuel (wood) overcame the electric energy consumed by the motors. The air relative humidity and temperature exercised influence in the drying time. The combination that provided larger energy efficiency was the continuous ventilation drying, with revolving times of 40 minutes each 2 hours. (author)

Application of CaO-Based Bed Material for Dual Fluidized Bed Steam Biomass Gasification

Science.gov (United States)

Koppatz, S.; Pfeifer, C.; Kreuzeder, A.; Soukup, G.; Hofbauer, H.

Gasification of biomass is a suitable option for decentralized energy supply based on renewable sources in the range of up to 50 MW fuel input. The paper presents the dual fluidized bed (DFB) steam gasification process, which is applied to generate high quality and nitrogen-free product gas. Essential part of the DFB process is the bed material used in the fluidized reactors, which has significant impact on the product gas quality. By the use of catalytically active bed materials the performance of the overall process is increased, since the bed material favors reactions of the steam gasification. In particular, tar reforming reactions are favored. Within the paper, the pilot plant based on the DFB process with 100kW fuel input at Vienna University of Technology, Austria is presented. Actual investigations with focus on CaO-based bed materials (limestone) as well as with natural olivine as bed material were carried out at the pilot plant. The application of CaO-based bed material shows mainly decreased tar content in the product gas in contrast to experiments with olivine as bed material. The paper presents the results of steam gasification experiments with limestone and olivine, whereby the product gas composition as well as the tar content and the tar composition are outlined.

Agglomeration of ash during combustion of peat and biomass in fluidized-bed reactors. Development of image analysis technique based on scanning electron microscopy; Tuhkan muuntuminen leijukerroskaasutuksessa ja -poltossa. Haitallisten hivenmetallien vapautuminen ja alkalien kaeyttaeytyminen

Energy Technology Data Exchange (ETDEWEB)

Kauppinen, E. [VTT Chemistry, Espoo (Finland); Arpiainen, V.; Jokiniemi, J. [VTT Energy, Espoo (Finland)] [and others

1996-12-01

The objective of the project is to study the behaviour of alkali metals (Na and K) and hazardous trace elements (Sb, As, Be, Cd, Cr, Co, Pb, Mn, Ni, Se and Zn) during fluidized bed combustion and gasification of solid fuels. The areas of interest are the release of elements studied from the bed and the behaviour of gaseous and particle-phase species after the release from the bed. During 1995 combustion and gasification experiments of Polish coal in bubbling bed were carried out with a laboratory scale fluidized bed gasifier in atmospheric pressure. Flue gas samples were drawn from the freeboard of the reactor and cooled quickly using a dilution probe. Ash particle size distributions were determined using low pressure impactors and differential mobility analyser. The morphology of the ash particles was studied with a scanning electron microscope (SEM) and will be further studied with transmission electron microscopy (TEM). The ash matrix elements (Si, Al, Fe, Ca and Mg) and the alkali metals (Na and K) were not significantly vaporized during the combustion process. More than 99 % of each of these elements was found in ash particles larger than 0.4 {mu}m. In Polish coal the alkali metals are bound mainly in silicates. The alkali metals were not released from the silicate minerals during the combustion process. A significant fraction of As, Cd and Pb was vaporized, released as gaseous species from the fuel particle and condensed mainly on the fine ash particles. 20 - 34 % of cadmium was present in fly ash particles smaller than 0.6 {mu}m (during combustion in 950 deg C), whereas only 1 % of the total ash was in this size fraction. All of the hazardous trace elements studied (As, Be, Cd, Co, Cr, Mn and Zn) were enriched in ash size fraction 0.6 - 5 {mu}m. The enrichment of Co, Cr, Mn, Ni, Pb and Sb was more significant during combustion in 950 deg C than in lower temperature (850 deg C)

Biodegradation of phenolic waste liquors in stirred-tank, packed-bed, and fluidized-bed bioreactors

Energy Technology Data Exchange (ETDEWEB)

Holladay, D W; Hancher, G W; Chilcote, D D; Scott, C D

1978-11-01

The biological degradation of phenolic scrub liquors similar to those that arise in coal conversion processes was studied for symbiotic bacterial populations contained in a continuously stirred tank bioreactor, a three-phase packed-bed bioreactor, and a three-phase, fluidized-bed bioreactor. The conversions of phenol compounds were comparable in the three-phase, packed-bed bioreactor and the continuously stirred tank bioreactor; however, the packed-bed bioreactor degradation rates were as much as twice those in the continuously stirred tank bioreactor, and packed-bed bioreactor retention times were as low as one- tenth those of the continuously stirred tank bioreactors (minimum time was 12 hours).

Bed and bed-site reuse by western lowland gorillas (Gorilla g. gorilla) in Moukalaba-Doudou National Park, Gabon.

Science.gov (United States)

Iwata, Yuji; Ando, Chieko

2007-01-01

In this paper we describe bed (nest) and bed-site reuse by western lowland gorillas (Gorilla g. gorilla) in Moukalaba-Doudou National Park, south-eastern Gabon. During an eight-month study 44 bed sites and 506 beds were found. Among these, 38.6% of bed sites and 4.1% of beds were reused. We analyzed the monthly frequency of bed-site reuse in relation to rainfall, fruit abundance, and fruit consumption by the gorillas. The different frequency of bed-site reuse in the rainy and dry seasons was not significant. More bed-site reuse was observed during the fruiting season than during the non-fruiting season. Results from fecal analysis suggested that gorillas ate more fruit in the fruiting season than in the non-fruiting season. The frugivorous diet of western gorillas may possibly cause gorillas to stay in some areas and, consequently, reuse their bed sites. Reuse of bed sites by gorillas suggests their frequent return to an area where preferred fruit is readily available. A higher percentage of arboreal beds may also affect bed-site reuse, because of the shortage of bed material.

Steam atmosphere drying concepts using steam exhaust recompression

Energy Technology Data Exchange (ETDEWEB)

DiBella, F.A. (TECOGEN, Inc., Waltham, MA (United States))

1992-08-01

In the US industrial drying accounts for approximately 1.5 quads of energy use per year. Annual industrial dryer expenditures are estimated to be in the $500 million range. Industrial drying is a significant energy and monetary expense. For the thermal drying processes in which water is removed via evaporation from the feedstock, attempts have been made to reduce the consumption of energy using exhaust waste heat recovery techniques, improved dryer designs, or even the deployment of advanced mechanical dewatering techniques. Despite these efforts, it is obvious that a large amount of thermal energy is often still lost if the latent heat of evaporation from the evaporated water cannot be recovered and/or in some way be utilized as direct heat input into the dryer. Tecogen Inc. is conducting research and development on an industrial drying concept. That utilizes a directly or indirectly superheated steam cycle atmosphere with exhaust steam recompression to recover the latent heat in the exhaust that would otherwise be lost. This approach has the potential to save 55 percent of the energy required by a conventional air dryer. Other advantages to the industrial dryer user include: A 35-percent reduction in the yearly cost per kg[sub evap] to dry wet feedstock, Reduced airborne emissions, Reduced dry dust fire/explosion risks, Hot product not exposed to oxygen thus, the product quality is enhanced, Constant rate drying in steam atmosphere, Reduced dryer size and cost, Reduced dryer heat losses due to lower dryer inlet temperatures. Tecogen has projected that the steam atmosphere drying system is most suitable as a replacement technology for state-of-the-art spray, flash, and fluidized bed drying systems. Such systems are utilized in the food and kindred products; rubber products; chemical and allied products; stone, clay, and glass; textiles; and pulp and paper industrial sectors.

Steam atmosphere drying concepts using steam exhaust recompression

Energy Technology Data Exchange (ETDEWEB)

DiBella, F.A. [TECOGEN, Inc., Waltham, MA (United States)

1992-08-01

In the US industrial drying accounts for approximately 1.5 quads of energy use per year. Annual industrial dryer expenditures are estimated to be in the $500 million range. Industrial drying is a significant energy and monetary expense. For the thermal drying processes in which water is removed via evaporation from the feedstock, attempts have been made to reduce the consumption of energy using exhaust waste heat recovery techniques, improved dryer designs, or even the deployment of advanced mechanical dewatering techniques. Despite these efforts, it is obvious that a large amount of thermal energy is often still lost if the latent heat of evaporation from the evaporated water cannot be recovered and/or in some way be utilized as direct heat input into the dryer. Tecogen Inc. is conducting research and development on an industrial drying concept. That utilizes a directly or indirectly superheated steam cycle atmosphere with exhaust steam recompression to recover the latent heat in the exhaust that would otherwise be lost. This approach has the potential to save 55 percent of the energy required by a conventional air dryer. Other advantages to the industrial dryer user include: A 35-percent reduction in the yearly cost per kg{sub evap} to dry wet feedstock, Reduced airborne emissions, Reduced dry dust fire/explosion risks, Hot product not exposed to oxygen thus, the product quality is enhanced, Constant rate drying in steam atmosphere, Reduced dryer size and cost, Reduced dryer heat losses due to lower dryer inlet temperatures. Tecogen has projected that the steam atmosphere drying system is most suitable as a replacement technology for state-of-the-art spray, flash, and fluidized bed drying systems. Such systems are utilized in the food and kindred products; rubber products; chemical and allied products; stone, clay, and glass; textiles; and pulp and paper industrial sectors.

Breakthrough analysis for water disinfection using silver nanoparticles coated resin beads in fixed-bed column

International Nuclear Information System (INIS)

Mthombeni, Nomcebo H.; Mpenyana-Monyatsi, Lizzy; Onyango, Maurice S.; Momba, Maggie N.B.

2012-01-01

Highlights: ► Performance of silver nanoparticles coated resin in water disinfection is presented. ► Sigmoidal models are used to describe breakthrough curves. ► The performance of the media in water disinfection is affected by process variables. ► Test with environmental water shows the media is effective in water disinfection. - Abstract: This study demonstrates the use of silver nanoparticles coated resin beads in deactivating microbes in drinking water in a column filtration system. The coated resin beads are characterized using X-ray diffraction (XRD), Fourier transform infra-red (FT-IR), scanning electron microscope (SEM), transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS) to confirm the functional groups, morphology and the presence of silver nanoparticles on the surface of the resin. The performance of the coated resin is evaluated as a function of bed mass, initial bacterial concentration and flow rate using Escherichia coli as model microbial contaminant in water. The survival curves of E. coli are expressed as breakthrough curves (BTCs), which are modeled using sigmoidal regression equations to obtain relevant rate parameters. The number of bed volumes processed at breakthrough point and capacity of the bed are used as performance indicators. Results show that performance increases with a decrease in initial bacterial concentration, an increase in flow rate and an increase in bed mass.

The effect of vibration on bed voidage behaviors in fluidized beds with large particles

Directory of Open Access Journals (Sweden)

H. Jin

2007-09-01

Full Text Available The effects of vibration parameters, operating conditions and material properties on bed voidage were investigated using an optical fiber probe approach in a vibrating fluidized bed with a diameter of 148 mm. Variables studied included frequency (0-282 s-1, amplitude (0 mm-1 mm, bed height (0.1 m-0.4 m as well as four kinds of particles (belonging to Geldart's B and D groups. The axial and radial voidage distribution with vibration is compared with that without vibration, which shows vibration can aid in the fluidization behaviors of particles. For a larger vibration amplitude, the vibration seriously affects bed voidage. The vibration energy can damp out for particle layers with increasing the bed height. According to analysis of experimental data, an empirical correlation for predicting bed voidage, giving good agreement with the experimental data and a deviation within ±15%, was proposed.

The microelectronics and photonics test bed (MPTB) space, ground test and modeling experiments

International Nuclear Information System (INIS)

Campbell, A.

1999-01-01

This paper is an overview of the MPTB (microelectronics and photonics test bed) experiment, a combination of a space experiment, ground test and modeling programs looking at the response of advanced electronic and photonic technologies to the natural radiation environment of space. (author)

Equipment selection for atmospheric drying

Energy Technology Data Exchange (ETDEWEB)

Sharma, P D; Bhattacharyya, S [Nuclear Power Corporation, Bhabha Atomic Research Centre, Mumbai (India)

1994-06-01

Heavy water management is a major factor in deciding the economics of the PHWRs. Hence it is necessary to have an efficient recovery system, for the heavy water vapour escaping from various process systems and maintain a dry atmosphere in the recovery areas. While the basic objective of the atmospheric drying system is to maximize recovery and to minimize stack losses, it is equally important to optimally design the system with due consideration to operational and maintenance aspects. At present, heavy water vapour recovery in the existing Nuclear Power Plants (NPPs) is carried out by dryers of dual fixed bed design. While moving bed design could have some advantages, this has not been adopted so far because of the cumbersome mechanical design involved and special requirements for nuclear application. Developmental work done in this direction has resulted in compact alternative designs. In one of the designs, the change over from adsorption to regeneration is achieved by rotating the bed slowly. This concept is further refined in another alternative using a dessicant wheel. This paper contains brief equipment description of different designs; enumerates the design requirements of an atmospheric drying system for reactor building; describes steps for designing fixed bed type D{sub 2}O vapour recovery system, and highlights advances in dryer technology. (author). 2 refs., 4 figs., 1 ill.

Selenate removal in methanogenic and sulfate-reducing upflow anaerobic sludge bed reactors

NARCIS (Netherlands)

Lenz, M.; Hullebusch, van E.D.; Hommes, G.; Corvini, P.F.X.; Lens, P.N.L.

2008-01-01

This paper evaluates the use of upflow anaerobic sludge bed (UASB) bioreactors (30 degrees C, pH = 7.0) to remove selenium oxyanions from contaminated waters (790 mu g Se L-1) under methanogenic and sulfate-reducing conditions using lactate as electron donor. One UASB reactor received sulfate at

Loading and Unloading Weaned Pigs: Effects of Bedding Types, Ramp Angle, and Bedding Moisture

Directory of Open Access Journals (Sweden)

Arlene Garcia

2014-12-01

Full Text Available The use of non-slip surfaces during loading and unloading of weaned pigs plays an important role in animal welfare and economics of the pork industry. Currently, the guidelines available only suggest the use of ramps below 20° to load and unload pigs. Three ramp angles (0°, 10° or 20°, five bedding materials (nothing, sand, feed, wood shavings or wheat straw hay, two moistures (dry or wet bedding; >50% moisture over two seasons (>23.9 °C summer, <23.9 °C winter were assessed for slips/falls/vocalizations (n = 6,000 pig observations. “Score” was calculated by the sum of slips, falls, and vocalizations. With the exception of using feed as a bedding, all beddings provided some protection against elevated slips, falls, and vocalizations (P < 0.01. Providing bedding reduced (P < 0.05 scores regardless of whether the bedding was dry or wet. Scores increased as the slope increased (P < 0.01. Provision of bedding, other than feed, at slopes greater than zero, decreased slips, falls and vocalizations. The total time it took to load and unload pigs was

Experimental studies on the coolability of packed beds. Flooding of hot dry packed beds

International Nuclear Information System (INIS)

Leininger, S.; Kulenovic, R.; Laurien, E.

2013-01-01

In case of a severe accident in a nuclear power plant meltdown of the reactor core can occur and form a packed bed in the lower plenum of the reactor pressure vessel (RPV) after solidification due to contact with water. The removal of after-heat and the long-term coolability is of essential interest. The efficient injection of cooling water into the packed bed has to be assured without endangering the structural integrity of the reactor pressure vessel. The experiments performed aimed to study the dry-out and the quenching (flooding) of hot dry packed beds. Two different inflow variants, bottom- and top-flooding including the variation of the starting temperature of the packed bed and the injection rate were studied. In case of bottom flooding the quenching time increases with increasing packed bed temperature and decreasing injection rate. In case of top flooding the flow pattern is more complex, in a first phase the water flows preferentially toward the RPV wall, the flow paths conduct the water downwards. The flow resistance of the packed bed increases with increasing bed temperatures. The quenching temperatures increase significantly above average.

Environmental protection stability of river bed and banks using convex, concave, and linear bed sills.

Science.gov (United States)

Keshavarzi, Alireza; Noori, Lila Khaje

2010-12-01

River bed scourings are a major environmental problem for fish and aquatic habitat resources. In this study, to prevent river bed and banks from scouring, different types of bed sills including convex, concave and linear patterns were installed in a movable channel bed in a laboratory flume. The bed sills were tested with nine different arrangements and under different flow conditions. To find the most effective bed sill pattern, the scouring depth was measured downstream of the bed sill for a long experimental duration. The scour depth was measured at the middle and at the end of each experimental test for different ratios of the arch radius to the channel width [r/w]. The experimental results indicated that the convex pattern with r/w=0.35 produced minimum bed scouring depth at the center line whereas the concave pattern with r/w=0.23 produced the minimum scour depth at the wall banks. Therefore, the convex pattern was the most effective configuration for prevention of scouring at the center line of the river while the concave pattern was very effective to prevent scouring at the river banks. These findings can be suggested to be used in practical applications.

Experimental study of pistachio drying behavior in a mixed-mode PV operated forced convection solar dryer

Energy Technology Data Exchange (ETDEWEB)

Zangiabadi, B [Univ. of Stavanger, Stavanger (Norway); Ameri, M; Mahmoudabadi, M M [Shahid Bahonar Univ., Kerman (Iran, Islamic Republic of)

2008-07-01

According to FAO statistics, Iran is the largest exporter of pistachios. Kerman province -south east of Iran- has approximately 200000 hectares of pistachio orchards, which provides practically 80% of whole country production of pistachios. After harvesting the pistachio, nuts must be washed to prevent staining. Therefore the nuts have almost 40% moisture content and it must be decreased to storage moisture of 6% or below. Simply decreasing in the moisture content of the products is called drying. In some areas where the environment conditions meet the minimum standard, solar drying can be an alternative approach for drying agricultural products. This work deals with the design, construction and testing a mixed-mode forced convection PV operated solar dryer. (orig.)

Performance of Heat Pump Dryer for Kaffir Lime Leaves and Quality of Dried Products under Different Temperatures and Media

OpenAIRE

N. Poomsa-ad; K. Deejing; L. Wiset

2011-01-01

This research is to study the performance of heat pump dryer for drying of kaffir lime leaves under different media and to compare the color values and essential oil content of final products after drying. In the experiments, kaffir lime leaves were dried in the closed-loop system at drying temperatures of 40, 50 and 60 oC. The drying media used in this study were hot air, CO2 and N2 gases. The velocity of drying media in the drying chamber was 0.4 m/s with bypass ratio o...

Particle size control of detergents in mixed flow spray dryers

Directory of Open Access Journals (Sweden)

Mark Jonathan Crosby

2015-03-01

Full Text Available Particle size is a key quality parameter of a powder detergent as it determines its performance, the bulk density and the look and feel of the product. Consequently, it is essential that particle size is controlled to ensure the consistency of performance when comparing new formulations. The majority of study reported in the literature relating to particle size control, focuses on the spray produced by the atomisation technique. One approach advocated to achieve particle size control is the manipulation of the ratio of the mass slurry rate and mass flow rate of gas used for atomisation. Within this study, ratio control was compared with an automatic cascade loop approach using online measurements of the powder particle size on a small-scale pilot plant. It was concluded that cascade control of the mean particle size, based on manipulating the mass flow rate of gas, resulted in tighter, more responsive control. The effect of a ratio change varied with different formulations and different slurry rates. Furthermore, changes in slurry rate caused complications, as the impact on particle size growth in the dryer is non-linear and difficult to predict. The cascade loop enables further study into the effect of particle size on detergent performance.

Fluidized bed coupled rotary reactor for nanoparticles coating via atomic layer deposition

Energy Technology Data Exchange (ETDEWEB)

Duan, Chen-Long; Liu, Xiao; Chen, Rong, E-mail: rongchen@mail.hust.edu.cn, E-mail: bshan@mail.hust.edu.cn [State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074 (China); Shan, Bin, E-mail: rongchen@mail.hust.edu.cn, E-mail: bshan@mail.hust.edu.cn [State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074 (China)

2015-07-15

A fluidized bed coupled rotary reactor has been designed for coating on nanoparticles (NPs) via atomic layer deposition. It consists of five major parts: reaction chamber, dosing and fluidizing section, pumping section, rotary manipulator components, as well as a double-layer cartridge for the storage of particles. In the deposition procedure, continuous fluidization of particles enlarges and homogenizes the void fraction in the particle bed, while rotation enhances the gas-solid interactions to stabilize fluidization. The particle cartridge presented here enables both the fluidization and rotation acting on the particle bed, demonstrated by the analysis of pressure drop. Moreover, enlarged interstitials and intense gas–solid contact under sufficient fluidizing velocity and proper rotation speed facilitate the precursor delivery throughout the particle bed and consequently provide a fast coating process. The cartridge can ensure precursors flowing through the particle bed exclusively to achieve high utilization without static exposure operation. By optimizing superficial gas velocities and rotation speeds, minimum pulse time for complete coating has been shortened in experiment, and in situ mass spectrometry showed the precursor usage can reach 90%. Inductively coupled plasma-optical emission spectroscopy results suggested a saturated growth of nanoscale Al{sub 2}O{sub 3} films on spherical SiO{sub 2} NPs. Finally, the uniformity and composition of the shells were characterized by high angle annular dark field-transmission electron microscopy and energy dispersive X-ray spectroscopy.

The effect of bed non-uniformities and porosity of particles on dryout in boiling particle beds

International Nuclear Information System (INIS)

Macbeth, R.V.; Mogford, D.J.; Willshire, S.J.

1988-03-01

This report relates to an on-going experimental programme concerned with the coolability of beds of reactor core debris or rubble immersed in a liquid coolant, as might occur in an accident situation. The objectives are to develop experimental techniques, improve the understanding of bed cooling mechanisms, determine dry-out limitations of various bed configurations and particle shapes and sizes and devise ways of improving bed coolability. The report concentrates on a recently discovered effect on bed coolability of particle porosity, such as exists in fragmented UO 2 fuel pellets. It is shown that porosity can lower bed dry-out powers by a factor of 4 or 5. A mechanism which explains the effect is presented. The report also gives results of bed non-uniformities obtained by mixing glass particles with the dielectrically heated 'ferrite' particles used in the experiments. (author)

Stabilizing Effects of Bacterial Biofilms: EPS Penetration and Redistribution of Bed Stability Down the Sediment Profile

Science.gov (United States)

Chen, X. D.; Zhang, C. K.; Zhou, Z.; Gong, Z.; Zhou, J. J.; Tao, J. F.; Paterson, D. M.; Feng, Q.

2017-12-01

Biofilms, consisting of microorganisms and their secreted extracellular polymeric substances (EPSs), serve as "ecosystem engineers" stabilizing sedimentary environments. Natural sediment bed provides an excellent substratum for biofilm growth. The porous structure and rich nutrients allow the EPS matrix to spread deeper into the bed. A series of laboratory-controlled experiments were conducted to investigate sediment colonization of Bacillus subtilis and the penetration of EPS into the sediment bed with incubation time. In addition to EPS accumulation on the bed surface, EPS also penetrated downward. However, EPS distribution developed strong vertical heterogeneity with a much higher content in the surface layer than in the bottom layer. Scanning electron microscope images of vertical layers also displayed different micromorphological properties of sediment-EPS matrix. In addition, colloidal and bound EPSs exhibited distinctive distribution patterns. After the full incubation, the biosedimentary beds were eroded to test the variation of bed stability induced by biological effects. This research provides an important reference for the prediction of sediment transport and hence deepens the understanding of the biologically mediated sediment system and broadens the scope of the burgeoning research field of "biomorphodynamics."

Performance of evaporator-collector and air collector in solar assisted heat pump dryer

International Nuclear Information System (INIS)

Hawlader, M.N.A.; Rahman, S.M.A.; Jahangeer, K.A.

2008-01-01

A solar assisted heat pump dryer has been designed, fabricated and tested. This paper presents the performance of the evaporator-collector and the air collector when operated under the same meteorological conditions. ASHRAE standard procedure for collector testing has been followed. The evaporator-collector of the heat pump is acting directly as the solar collector, and the temperature of the refrigerant at the inlet to the evaporator-collector always remained below the ambient temperature. Because of the rejection of sensible and latent heats of air at the dehumidifier, the temperature at the inlet to the air collector is lower than that of the ambient air. Hence, the thermal efficiency of the air collector also increases due to a reduction of losses from the collector. The efficiencies of the evaporator-collector and the air collector were found to vary between 0.8-0.86 and 0.7-0.75, respectively, when operated under the meteorological conditions of Singapore

Design of a Low Cost Smart Dryer Temperature Measurement System for Tea Factories

Directory of Open Access Journals (Sweden)

Utpal SARMA

2009-09-01

Full Text Available This paper presents the design of a low cost smart dryer temperature measurement system for Tea Factories using K-type Thermocouple implementing linearization polynomial. The thermo emf is amplified by an instrumentation amplifier having high CMRR (106 dB and high input impedance (1012 Ohm. The analog signal is converted to digital form with the help of an SPI compatible 12-bit ADC. Data acquisition and transmission is done with an 8- bit microcontroller. As the dependence of thermo emf on temperature is not linear hence it is fitted with a polynomial. NIST data for K-type TC is taken as a standard for this fitting. The error with linear fit and polynomial fit is also presented. The digital data is corrected according to the polynomial and sent to a PC located at a remote control room for monitoring and data logging via RS232C communication. The performance of the entire system is discussed in the paper.

Modelling and experimental studies on a mixed-mode natural convection solar crop-dryer

Energy Technology Data Exchange (ETDEWEB)

Forson, F.K. [Department of Mechanical Engineering, Kwame Nkrumah University of Science and Technology, Kumasi (Ghana); Nazha, M.A.A.; Rajakaruna, H. [School of Engineering and Technology, De Montfort University, Queens Building, Leicester LE1 9BH (United Kingdom)

2007-03-15

A mathematical model for drying agricultural products in a mixed-mode natural convection solar crop dryer (MNCSCD) using a single-pass double-duct solar air-heater (SPDDSAH) is presented. The model was developed in parallel with experimental work. The model comprises the air-heating process model, the drying model and the technical performance criteria model. The governing equations of the drying air temperature and humidity ratio; the material temperature and its moisture content; and performance criteria indicators are derived. The model requires the solution of a number of interrelated non-linear equations and a set of simultaneous differential equations. Results from experimental studies used for generating the required experimental data for validating the model are presented. Results of simulation runs using the model are presented and compared with the experimental data. It is shown that the model can predict the performance of the MNCSCD fairly accurately and therefore can be used as a design tool for prototype development. (author)

Solar drying system for tropical fruits and a model for drying bananas in a static column dryer; Sistema de secagem solar para frutos tropicais e modelagem da secagem de banana em um secador de coluna estatica

Energy Technology Data Exchange (ETDEWEB)

Costa, Antonio Raimundo da Silva

2008-01-15

An electric solar dryer consisting of a solar collector, a drying chamber, an exhaust fan and a fan to promote forced hot air convection were projected, built and tested . Banana drying experiments were also carried out in a static column dryer to model the drying and to obtain parameters that can be used as a first approximation in the modeling of an electric solar dryer, depending on the similarity of the experimental conditions between the two drying systems. From the banana drying experiments conducted in the static column dryer, we obtained food weight data as a function of aqueous concentration and temperature. Simplified mathematical models of the banana drying were made, based on Fick's and Fourier's second equations, which were tested with the experimental data. We determined and/or modeled parameters such as banana moisture content, density, thin layer drying curves, equilibrium moisture content, molecular diffusivity of the water in banana D{sub AB}, extemal mass transfer coefficient k{sub M}, specific heat C{sub p}, thermal conductivity k, latent heat of water evaporation in the food L{sub food}, time to heat food, and minimum energy and power required to heat the food and evaporate the water. When we considered the shrinkage of radius R of a banana, the calculated values of D{sub AB} and k{sub M} generally better represent the phenomenon of water diffusion in a solid. The latent heat of water evaporation in the food L{sub food} calculated by modeling is higher than the latent heat of pure water evaporation L{sub water}. The values calculated for D{sub AB} and K{sub M} that best represent the drying were obtained with the analytical model of the present paper. These values had good agreement with those assessed with a numeric model described in the literature, in which convective boundary condition and food shrinkage are considered. Using parameters such as C{sub p}, D{sub AB}, k, k{sub M} and L{sub food}, one can elaborate the preliminary

Numerical modelling of multi-pass solar dryer filled with granite pebbles for thermal storage enhancement

International Nuclear Information System (INIS)

Kareem, M W; Habib, K; Ruslan, M H

2015-01-01

In this paper, a theoretical modelling of a cheap solar thermal dryer for small and medium scale farmers with multi-pass approach has been investigated. Comsol Multiphysics modelling tool was employed using numerical technique. The rock particles were used to enhance the thermal storage of the drying system. The local weather data were used during the simulation while parameters and coefficients were sourced from literature. An improvement on efficiency of up to 7% was recorded with error of 10 -5 when compared with the reported double pass solar collector. A fair distribution of hot air within the cabinets was also achieved. Though the modelling tool used was robust but the characterization of the system materials need to be done to improve the system accuracy and better prediction. (paper)

Agglomeration of bed material: Influence on efficiency of biofuel fluidized bed boiler

Directory of Open Access Journals (Sweden)

Ryabov Georgy A.

2003-01-01

Full Text Available The successful design and operation of a fluidized bed combustor requires the ability to control and mitigate ash-related problems. The main ash-related problem of biomass filing boiler is agglomeration. The fluidized bed boiler with steam capacity of 66 t/h (4 MPa, 440 °C was started up at the Arkhangelsk Paper-Pi dp-Plant in 2001. This boiler was manufactured by the Russian companies "Energosofin" and "Belenergomash" and installed instead of the existing boiler with mechanical grate. Some constructional elements and steam drum of existing boiler remained unchanged. The primary air fan was installed past the common air fan, which supply part of the air into 24 secondary airports. First operating period shows that the bed material is expanded and then operator should increase the primary air rate, and the boiler efficiency dramatically decreases. Tills paper presents some results of our investigations of fuel, bed and fly ash chemical compositions and other characteristics. Special experiments were carried out to optimize the bed drain flow rate. The influence of secondly air supply improvement on mixing with the main flow and boiler efficiency are given.

Seaweed beds support more juvenile reef fish than seagrass beds in a south-western Atlantic tropical seascape

Science.gov (United States)

Eggertsen, L.; Ferreira, C. E. L.; Fontoura, L.; Kautsky, N.; Gullström, M.; Berkström, C.

2017-09-01

Seascape connectivity is regarded essential for healthy reef fish communities in tropical shallow systems. A number of reef fish species use separate adult and nursery habitats, and hence contribute to nutrient and energy transfer between habitats. Seagrass beds and mangroves often constitute important nursery habitats, with high structural complexity and protection from predation. Here, we investigated if reef fish assemblages in the tropical south-western Atlantic demonstrate ontogenetic habitat connectivity and identify possible nurseries on three reef systems along the eastern Brazilian coast. Fish were surveyed in fore reef, back reef, Halodule wrightii seagrass beds and seaweed beds. Seagrass beds contained lower abundances and species richness of fish than expected, while Sargassum-dominated seaweed beds contained significantly more juveniles than all other habitats (average juvenile fish densities: 32.6 per 40 m2 in Sargassum beds, 11.2 per 40 m2 in back reef, 10.1 per 40 m2 in fore reef, and 5.04 per 40 m2 in seagrass beds), including several species that are found in the reef habitats as adults. Species that in other regions worldwide (e.g. the Caribbean) utilise seagrass beds as nursery habitats were here instead observed in Sargassum beds or back reef habitats. Coral cover was not correlated to adult fish distribution patterns; instead, type of turf was an important variable. Connectivity, and thus pathways of nutrient transfer, seems to function differently in east Brazil compared to many tropical regions. Sargassum-dominated beds might be more important as nurseries for a larger number of fish species than seagrass beds. Due to the low abundance of structurally complex seagrass beds we suggest that seaweed beds might influence adult reef fish abundances, being essential for several keystone species of reef fish in the tropical south-western Atlantic.

Investigation of heat transfer in bed and freeboard of fluidized bed combustors

International Nuclear Information System (INIS)

Mitor, V.V.; Matsnev, V.V.; Sorokin, A.P.

1986-01-01

Experimental results for heat transfer between immersed bundles of bare tubes and fluidized beds are reported. The experimental results are obtained on industrial boilers with a bed area from 2,5 to 4 m/sup 2/ under conditions of long term operation. The bed temperature range has been 1073 0 K-1233 0 K, gas velocity between 1,8-4,5 m/s, mean particle size from 1,5 mm to 6,0 mm, freeboard furnace height of 2,3 and 5 m. The obtained data are compared with experimental results from literature

Microstructure and Mechanical Properties of Long Ti-6Al-4V Rods Additively Manufactured by Selective Electron Beam Melting Out of a Deep Powder Bed and the Effect of Subsequent Hot Isostatic Pressing

Science.gov (United States)

Lu, S. L.; Tang, H. P.; Ning, Y. P.; Liu, N.; StJohn, D. H.; Qian, M.

2015-09-01

An array of eight long Ti-6Al-4V rods (diameter: 12 mm; height: 300 mm) have been additively manufactured, vertically and perpendicular to the powder bed, by selective electron beam melting (SEBM). The purpose was to identify and understand the challenges of fabricating Ti-6Al-4V samples or parts from a deep powder bed (more than 200-mm deep) by SEBM and the necessity of applying post heat treatment. The resulting microstructure and mechanical properties of these Ti-6Al-4V rods were characterized along their building ( i.e., axial) direction by dividing each rod into three segments (top, middle, and bottom), both before ( i.e., as-built) and after hot isostatic pressing (HIP). The as-built microstructure of each rod was inhomogeneous; it was coarsest in the top segment, which showed a near equilibrium α- β lamellar structure, and finest in the bottom segment, which featured a non-equilibrium mixed structure. The tensile properties varied along the rod axis, especially the ductility, but all tensile properties met the requirements specified by ASTM F3001-14. HIP increased the relative density from 99.03 pct of the theoretical density (TD) to 99.90 pct TD and homogenized the microstructure thereby leading to highly consistent tensile properties along the rod axis. The temperature of the stainless steel substrate used in the powder bed was monitored. The as-built inhomogeneous microstructure is attributed to the temperature gradient in the deep powder bed. Post heat treatment is thus necessary for Ti-6Al-4V samples or parts manufactured from a deep powder bed by SEBM. This differs from the additive manufacturing of small samples or parts from a shallow powder bed (less than 100-mm deep) by SEBM.

Improved lignin pyrolysis for phenolics production in a bubbling bed reactor--Effect of bed materials.

Science.gov (United States)

Li, Dongbing; Briens, Cedric; Berruti, Franco

2015-01-01

Lignin pyrolysis was studied in a bubbling fluidized bed reactor equipped with a fractional condensation train, using nitrogen as the fluidization gas. The effect of different bed materials (silica sand, lignin char, activated lignin char, birch bark char, and foamed glass beads) on bio-oil yield and quality was investigated for a pyrolysis temperature of 550 °C. Results how that a bed of activated lignin char is preferable to the commonly used silica sand: pyrolysis of Kraft lignin with a bed of activated lignin char not only provides a pure char product, but also a higher dry bio-oil yield (with a relative increase of 43%), lower pyrolytic water production, and better bio-oil quality. The bio-oil obtained from Kraft lignin pyrolysis with a bed of activated lignin char has a lower average molecular weight, less tar, more phenolics, and less acidity than when sand is used as bed material. Copyright © 2015 Elsevier Ltd. All rights reserved.

Energetic analysis of a wood fired grain drier; Analise energetica de secador de graos a lenha

Energy Technology Data Exchange (ETDEWEB)

Campos, Alessandro Torres [Universidade Estadual do Oeste do Parana (UNIOESTE), Marechal Candido Rondon, PR (Brazil). Grupo de Pesquisas em Ambiencia do Oeste do Parana], e-mail: atcampos3@yahoo.com.br; Melo, Evandro de Castro; Sousa e Silva, Juarez de [Universidade Federal de Vicosa (UFV), Vicosa, MG (Brazil). Dept. de Engenharia Agricola

2004-07-01

Aiming at the attendance of a small and medium size group of producers a four chambers fixed-bed dryer prototype with a mechanical revolving system was designed, constructed and energy performance tested. During drying for the prototype test, using coffee the revolving operation proceeded in two chambers which were connected to the dryer plenum at different positions and at a regular three-hours intervals; the other chambers remained static. The dryer operated at a drying-air temperature of 43 deg C and an air-flow of 21 m3 min-1 m-2. In the realized test the product moisture content was reduced from 43.1 to 12.7% w.b. over a 42-hours period. The specific energy consumption was 12.752 kJ per kilogram of evaporated water. The obtained results showed that chamber 1 which was submitted to the revolving operation presented the best work conditions due to your plenum connection position. (author)

Uranium bed oxidation vacuum process system

International Nuclear Information System (INIS)

McLeland, H.L.

1977-01-01

Deuterium and tritium gases are occluded in uranium powder for release into neutron generator tubes. The uranium powder is contained in stainless steel bottles, termed ''beds.'' If these beds become damaged, the gases must be removed and the uranium oxidized in order not to be flammable before shipment to ERDA disposal grounds. This paper describes the system and methods designed for the controlled degassing and oxidation process. The system utilizes sputter-ion, cryo-sorption and bellows pumps for removing the gases from the heated source bed. Removing the tritium gas is complicated by the shielding effect of helium-3, a byproduct of tritium decay. This effect is minimized by incremental pressure changes, or ''batch'' processing. To prevent runaway exothermic reaction, oxidation of the uranium bed is also done incrementally, or by ''batch'' processing, rather than by continuous flow. The paper discusses in detail the helium-3 shielding effect, leak checks that must be made during processing, bed oxidation, degree of gas depletion, purity of gases sorbed from beds, radioactivity of beds, bed disposal and system renovation

Practice Hospital Bed Safety

Science.gov (United States)

... Home For Consumers Consumer Updates Practice Hospital Bed Safety Share Tweet Linkedin Pin it More sharing options ... It depends on the complexity of the bed." Safety Tips CDRH offers the following safety tips for ...

Particle fuel bed tests

International Nuclear Information System (INIS)

Horn, F.L.; Powell, J.R.; Savino, J.M.

1985-01-01

Gas-cooled reactors, using packed beds of small diameter coated fuel particles have been proposed for compact, high-power systems. The particulate fuel used in the tests was 800 microns in diameter, consisting of a thoria kernel coated with 200 microns of pyrocarbon. Typically, the bed of fuel particles was contained in a ceramic cylinder with porous metallic frits at each end. A dc voltage was applied to the metallic frits and the resulting electric current heated the bed. Heat was removed by passing coolant (helium or hydrogen) through the bed. Candidate frit materials, rhenium, nickel, zirconium carbide, and zirconium oxide were unaffected, while tungsten and tungsten-rhenium lost weight and strength. Zirconium-carbide particles were tested at 2000 K in H 2 for 12 hours with no visible reaction or weight loss

Which techniques for an additional irradiation of the tumour bed in a breast cancer?

International Nuclear Information System (INIS)

Chenna, H.; Iraqi, M.; Ahmedou, M.M.; Berhil, H.; El Kacemi, H.; Hassouni, K.; Kebdani, T.; Benjaafar, N.; El Gueddari, B.K.

2010-01-01

The authors report a comparison of different techniques for an additional irradiation of the tumour bed, in terms of local control and aesthetic result in the case of a breast cancer. This additional irradiation has been delivered by electron beam in five fractions, high dose rate curie-therapy in two fractions, photon beam in five or six fractions, and low dose rate curie-therapy. The dose increase in the tumour bed allows the local control rate to be increased without compromising aesthetic results. However, the comparison of the different boost techniques does not reveal significant differences. Short communication

Statistical description of flume experiments on mixed-size bed-load transport and bed armoring processes

Science.gov (United States)

Chen, D.; Zhang, Y.

2008-12-01

The objective of this paper is to describe the statistical properties of experiments on non-uniform bed-load transport as well as the mechanism of bed armoring processes. Despite substantial effort made over the last two decades, the ability to compute the bed-load flux in a turbulent system remains poor. The major obstacles include the poor understanding of the formation of armor lays on bed surfaces. Such a layer is much flow-resistible than the underlying material and therefore significantly inhibits sediment transport from the reach. To study the problem, we conducted a flume study for mixed sand/gravel sediments. We observed that aggregated sediment blocks were the most common characters in armor layers - the largest sizes resist hydraulic forces, while the smaller sizes add interlocking support and prevent loss of fine material through gaps between the larger particles. Fractional transport rates with the existing of armor layers were measured with time by sediment trapping method at the end of flume. To address the intermittent and time-varying behavior of bed-load transport during bed armoring processes, we investigated the probability distribution of the fractional bed-load transport rates, and the underlying dynamic model derived from the continuous time random walk framework. Results indicate that it is critical to consider the impact of armor layers when a flow is sufficient to move some of the finer particles and yet insufficient to move all the larger particles on a channel bed.

Chaotic hydrodynamics of fluidized beds

Energy Technology Data Exchange (ETDEWEB)

Van der Stappen, M.L.M. [Unit Process and Systems Engineering, Advanced Manufacturing Technology Group, Unilever Research Laboratorium, Vlaardingen (Netherlands)

1996-12-31

The major goals of this thesis are: (1) to develop and evaluate an analysis method based on techniques from non-linear chaos theory to characterize the nonlinear hydrodynamics of gas-solids fluidized beds quantitatively; and (2) to determine the dependence of the chaotic invariants on the operating conditions and investigate how the chaos analysis method can be profitably applied to improve scale-up and design of gas-solids fluidized bed reactors. Chaos theory is introduced in chapter 2 with emphasis on analysis techniques for (experimental) time series, known from literature at the start of this work (1990-1991). In chapter 3, the testing of existing and newly developed techniques on both model and fluidized bed data is described. This leads to the development of the chaos analysis method to analyze measured pressure fluctuations time series of a fluidized bed. Following, in chapter 4, this method is tested and all choices for the parameters are evaluated. The influence of the experimental parameters and external disturbances on the measurements and analysis results is discussed and quantified. The result is a chaos measurement and analysis protocol, which is further used in this work. In chapter 5, the applications to fluidized beds are discussed. It is shown that the entropy is a good measure for the characterization of the dynamical behavior of gas-solids bubbling/slugging fluidized beds. Entropy is applied to characterize the influence of the operating conditions, to assess regime transitions and to analyze dimensionless similar beds of different scale. Quantitative design correlations that relate entropy to the operating parameters (including the bed diameter) are described. Finally, it is discussed how the results of this work might be used in scaling up the chaotic dynamics of fluidized beds. The overall conclusions and outlook from this work are presented in chapter 6. 182 refs.

Comparison of packed bed and fluidized bed membrane reactors for methane reforming

NARCIS (Netherlands)

Gallucci, F.; van Sint Annaland, M.; Kuipers, J.A.M.

2009-01-01

In this work the performance of different membrane reactor concepts, both fluidized bed and packed bed membrane reactors, have been compared for the reforming of methane for the production of ultra-pure hydrogen. Using detailed theoretical models, the required membrane area to reach a given

Effects of bed-load movement on flow resistance over bed forms

Indian Academy of Sciences (India)

Abstract. The effect of bed-load transport on flow resistance of alluvial channels with undulated bed was experimentally investigated. The experiments were carried out in a tilting flume 250mm wide and 12·5m long with glass-sides of rectan- gular cross-section and artificial dune shaped floor that was made from Plexi-glass.

Staged fluidized-bed combustion and filter system

International Nuclear Information System (INIS)

Mei, J.S.; Halow, J.S.

1994-01-01

A staged fluidized-bed combustion and filter system are described for substantially reducing the quantity of waste through the complete combustion into ash-type solids and gaseous products. The device has two fluidized-bed portions, the first primarily as a combustor/pyrolyzer bed, and the second as a combustor/filter bed. The two portions each have internal baffles to define stages so that material moving therein as fluidized beds travel in an extended route through those stages. Fluidization and movement is achieved by the introduction of gases into each stage through a directional nozzle. Gases produced in the combustor/pyrolyzer bed are permitted to travel into corresponding stages of the combustor/filter bed through screen filters that permit gas flow but inhibit solids flow. Any catalyst used in the combustor/filter bed is recycled. The two beds share a common wall to minimize total volume of the system. A slightly modified embodiment can be used for hot gas desulfurization and sorbent regeneration. Either side-by-side rectangular beds or concentric beds can be used. The system is particularly suited to the processing of radioactive and chemically hazardous waste. 10 figures

On changes in bed-material particles from a 550 MWth CFB boiler burning coal, bark and peat

Energy Technology Data Exchange (ETDEWEB)

Vesna Barisic; Mikko Hupa [Aabo Akademi Process Chemistry Centre, Turku (Finland). Combustion and Materials Chemistry

2007-02-15

This paper presents our observations on coating build up, morphology and the elemental composition of bed-material particles collected from a 550 MWth CFB boiler burning coal, bark and peat fuel/fuel mixture. The special focus was on the changes of the elemental composition of coating layer on bed-material particles when different fuels were burned. The results were obtained using a scanning electron microscope coupled with an energy depressive X-ray analyser (SEM/EDX). The results clearly show that properties of bed-material particles are a result of complex interaction between the fuels burned previously, and the fuels used at the time of sampling. Short communication. 8 refs., 1 fig., 2 tabs.

Bed Bugs and Schools

Science.gov (United States)

Bed bugs have long been a pest – feeding on blood, causing itchy bites and generally irritating their human hosts. They are successful hitchhikers, and can move from an infested site to furniture, bedding, baggage, boxes, and clothing.

Calculation of local bed to wall heat transfer in a fluidized-bed

International Nuclear Information System (INIS)

Kilkis, B.I.

1987-01-01

Surface to bed heat transfer in a fluidized-bed largely depends upon its local and global hydrodynamical behavior including particle velocity, particle trajectory, gas velocity, and void fraction. In this study, a computer program was developed in order to calculate the local bed to wall heat transfer, by accounting for the local and global instantaneous hydrodynamics of the bed. This is accomplished by utilizing the CHEMFLUB computer program. This information at a given location is interpreted so that the most appropriate heat transfer model is utilized for each time increment. These instantaneous heat transfer coefficient for the given location. Repeating the procedure for different locations, a space average heat transfer coefficient is also calculated. This report briefly summarizes the various heat transfer models employed and gives sample computer results reporting the case study for Mickley - Trilling's experimental set-up. Comparisons with available experimental data and correlations are also provided in order to compare and evaluate the computer results

Production of polycrystalline silicon by fluidized-bed-problems and recent progress of study

Energy Technology Data Exchange (ETDEWEB)

Kojima, Toshinori

1988-10-01

Concerning the production of polycrystalline silicon from SiH/sub 4/ by applying fluidized bed reaction, recent progress of study, problems involved, and countermeasures to them were reported. For the experiment, stainless tube with 50mm inside diameter attached with electric heater on the wall as auxillary heat source was used to measure the temperature distribution in the bed. As the diluting gas, hydrogen and argon were used to investigate the effect of diluent gas and it was understood that sort of diluent gas affected on the crogging and reaction rate. It was indicated that, in the fluidized bed reaction which gave large depositing area and high productivity, contamination was easily occurred. Observation of fine powder by electronic-microscope revealed that different diluent caused the difference of fine powder shape and that the higher the reaction temperature the more fine powder was produced. Crogging condition was affected by tower diameter, together with temperature and fluidizing conditions. In addition, two recent patents were introduced. 11 references, 10 figures.

Protecting Your Home from Bed Bugs

Science.gov (United States)

... your home: Inspect the luggage rack in your hotel room for bed bugs. Check secondhand furniture, beds, ... with Bed Bug Problems Discover. Accessibility EPA Administrator Budget & Performance Contracting Grants January 19, 2017 Web Snapshot ...

Solar drying of West Indian ginger (Zingiber officinale Roscoe) rhizome using a wire basket dryer

Energy Technology Data Exchange (ETDEWEB)

Balladin, D.A.; Headley, O. [University of the West Indies (Barbados). Dept. of Chemistry; Chang Yen, I. [University of the West Indies, St. Augustine (Trinidad and Tobago). Dept. of Chemistry; McGaw, D.R. [University of the West Indies, St. Augustine (Trinidad and Tobago). Dept. of Chemical Engineering

1996-09-01

A wire basket dryer (1.8 m x 0.9 m x 0.2 m) was used to dry sliced (0.15 cm) West Indian ginger (Zingiber officinale Roscoe) rhizome to an acceptable moisture content of 10.2% (dry weight basis) over a 3 day period. The optimum charge size was 14.97 kg, with a packing density of 462.04 kg m{sup -3} and a specific drying rate of 0.446 h{sup -1}. The quantities (determined by high-pressure liquid chromatography) of the main pungent principles (ginerol and shogaol) extracted from fresh, non-steam-distilled solar-dried and steam-distilled solar-dried ginger rhizomes showed increases of 0.068, 0.46 and 0.67 g [per 100 g (dry weight basis)], respectively, with a decrease in the oleoresin quality (reflected in pungency profile) of the same order. (author)

Biomass oxygen/steam gasification in a pressurized bubbling fluidized bed: Agglomeration behavior

International Nuclear Information System (INIS)

Zhou, Chunguang; Rosén, Christer; Engvall, Klas

2016-01-01

Highlights: • Dolomite is a superior material in preventing bed agglomeration. • Small molten ash particles deposited on magnesite at bed temperatures above 1000 °C. • The performance, when using magnesite, is sensitive to temperature disturbances. • The anti-agglomeration mechanisms of Ca- and Mg-bearing materials were discussed. - Abstract: In this study, the anti-agglomeration abilities of Ca- and Mg-containing bed materials, including dolomite and magnesite, in a pressurized bubbling fluidized bed gasifier using pine pellets and birch chips as feedstock, is investigated. The most typical bed material—silica sand—was also included as a reference for comparison. The sustainability of the operation was evaluated via analyzing the temperatures at different levels along the bed height. During the performances, the aim was to keep the temperature at the bottom zone of the reactor at around 870 °C. However, the success highly depends on the bed materials used in the bed and the temperature can vary significantly in case of agglomeration or bad mixing of bed materials and char particles. Both Glanshammar and Sala dolomites performed well with no observed agglomeration tendencies. In case of magnesite, the bed exhibited a high agglomeration tendency. Silica sand displayed the most severe agglomeration among all bed materials, even when birch chips with a low silica content was fed at a relatively low temperature. The solid samples of all the bed materials were inspected by light microscopy and Scanning Electron Microscopy (SEM). The Energy Dispersive Spectroscopy (EDS) detector was used to detect the elemental distribution in the surface. The crystal chemical structure was analyzed using X-ray Diffraction (XRD). Magnesite agglomerates glued together by big molten ash particles. There was no coating layer detected on magnesite particles at bed temperatures – below 870 °C. But when the temperature was above 1000 °C, a significant amount of small molten

An Apparatus for Bed Material Sediment Extraction From Coarse River Beds in Large Alluvial Rivers

Science.gov (United States)

Singer, M. B.; Adam, H.; Cooper, J.; Cepello, S.

2005-12-01

Grain size distributions of bed material sediment in large alluvial rivers are required in applications ranging from habitat mapping, calibration of sediment transport models, high resolution sediment routing, and testing of existing theories of longitudinal and cross steam sediment sorting. However, characterizing bed material sediment from coarse river beds is hampered by difficulties in sediment extraction, a challenge that is generally circumvented via pebble counts on point bars, even though it is unclear whether the bulk grain size distribution of bed sediments is well represented by pebble counts on bars. We have developed and tested a boat-based sampling apparatus and methodology for extracting bulk sediment from a wide range of riverbed materials. It involves the use of a 0.4 x 0.4 x 0.2 meter stainless steel toothed sampler, called the Cooper Scooper, which is deployed from and dragged downstream by the weight of a jet boat. The design is based on that of a river anchor such that a rotating center bar connected to a rope line in the boat aligns the sampler in the downstream direction, the teeth penetrate the bed surface, and the sampler digs into the bed. The sampler is fitted with lead weights to keep it from tipping over. The force of the sampler `biting' into the bed can be felt on the rope line held by a person in the boat at which point they let out slack. The boat then motors to the spot above the embedded sampler, which is hoisted to the water surface via a system of pulleys. The Cooper Scooper is then clipped into a winch and boom assembly by which it is brought aboard. This apparatus improves upon commonly used clamshell dredge samplers, which are unable to penetrate coarse or mixed bed surfaces. The Cooper Scooper, by contrast, extracts statistically representative bed material sediment samples of up to 30 kilograms. Not surprisingly, the sampler does not perform well in very coarse or armored beds (e.g. where surface material size is on the

The phenomenon of diminishing –returns in the use of bed nets and ...

African Journals Online (AJOL)

2014-03-01

Mar 1, 2014 ... treated bed nets and prompt malaria therapy in Tororo. Uganda, concluded the .... namely vaccination, cure and quarantine and yet cure for malaria actually ..... It is therefore the anti-malarial medicines given to their children that are .... his great assistance in the preparation of the electronic version of this ...

Power/heat production from biomass in Finland - Two modern Finnish examples

International Nuclear Information System (INIS)

Aeijaelae, M.

1997-01-01

According to this conference paper, Finland is a leading country in the utilization of biomass fuels for power and heat production. One reason is that peat and wood are the only indigenous fuels available in Finland. Other reasons are the strong forest industry and the widely adopted combined heat and power (CHP) production. CHP production is typical of process industry and municipal district heating. The most common boiler type in modern CHP plants is the fluidized bed type. District heating is the cheapest heating in municipalities with a few thousand inhabitants. Electric heating dominates in sparsely populated regions. CHP becomes attractive for populations of more than ten thousand. Two examples are described: (1) Rauhalahti Power Plant produces 140 MW of district heat, 65 MW of industrial steam and 87 MW of electricity. (2) Kuusamo Power Plant produces 6.1 MW electric energy and 17.6 MW district heat; its unique feature is the utilization of the bed mixing dryer for drying of the fuel prior to combustion, this dryer being the first of its kind in the world. 1 figure

Apparatus and process for controlling fluidized beds

Science.gov (United States)

Rehmat, Amirali G.; Patel, Jitendra G.

1985-10-01

An apparatus and process for control and maintenance of fluidized beds under non-steady state conditions. An ash removal conduit is provided for removing solid particulates from a fluidized bed separate from an ash discharge conduit in the lower portion of the grate supporting such a bed. The apparatus and process of this invention is particularly suitable for use in ash agglomerating fluidized beds and provides control of the fluidized bed before ash agglomeration is initiated and during upset conditions resulting in stable, sinter-free fluidized bed maintenance.

Fluidized bed boiler feed system

Science.gov (United States)

Jones, Brian C.

1981-01-01

A fluidized bed boiler feed system for the combustion of pulverized coal. Coal is first screened to separate large from small particles. Large particles of coal are fed directly to the top of the fluidized bed while fine particles are first mixed with recycled char, preheated, and then fed into the interior of the fluidized bed to promote char burnout and to avoid elutriation and carryover.

Fluidized bed incinerator development

International Nuclear Information System (INIS)

Ziegler, D.L.; Johnson, A.J.

1976-01-01

A fluidized bed incinerator is being developed for burning rad contaminated solid and liquid waste materials. In situ neutralization of acid gases by the bed material, catalytic afterburning, and gas filtration are used to produce a clean flue gas without the use of aqueous scrubbing

Effect of interprofessional student-led beds on emergency department performance indicators.

Science.gov (United States)

Meek, Robert; Morphet, Julia; Hood, Kerry; Leech, Michelle; Sandry, Kate

2013-10-01

The study aims to compare ED performance indicators between patients managed by students in an inter-professional learning (IPL) programme and comparable patients receiving usual ED care. An IPL programme ran for five separate 2 week periods during 2012. Four student-led beds were managed by four final year students (two medical, two nursing). Four control beds were matched for patient acuity. Data were gathered electronically from the ED information system. Comparisons of baseline characteristics and a range of ED performance indicators were made between patients managed in the student-led and control beds. Patient satisfaction with student care was surveyed. Characteristics of the 369 study and 365 control patients were similar. Median times to being seen by a nurse and a doctor were not significantly different between student-led and control beds, at 50 (19-103) versus 45 (20-93) min, and 84 (28-162) versus 91 (41-165) min, respectively. Median time to inpatient referral for admitted patients was significantly longer in student-led compared with control beds, being 142 (65-249) versus 101.5 (48-200) min, respectively. Median lengths of stay were similar between the student-led and control groups, being 263 (201-343) versus 303.5 (204-384) min for discharged patients, and 866 (571-1238) versus 745.5 (487-1168) min for inpatient ward admissions. Patients reported high levels of satisfaction with student care. There was little difference in performance indicators between patients managed by student teams as part of an IPL programme and a similar group receiving usual ED care. © 2013 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

Petrology and geochemistry of samples from bed-contact zones in Tunnel Bed 5, U12g-Tunnel, Nevada Test Site

International Nuclear Information System (INIS)

Connolly, J.R.; Keil, K.; Mansker, W.L.; Allen, C.C.; Husler, J.; Lowy, R.; Fortney, D.R.; Lappin, A.R.

1984-10-01

This report summarizes the detailed geologic characterization of samples of bed-contact zones and surrounding nonwelded bedded tuffs, both within Tunnel Bed 5, that are exposed in the G-Tunnel complex beneath Rainier Mesa on the Nevada Test Site (NTS). Original planning studies treated the bed-contact zones in Tunnel Bed 5 as simple planar surfaces of relatively high permeability. Detailed characterization, however, indicates that these zones have a finite thickness, are depositional in origin, vary considerably over short vertical and horizontal distances, and are internally complex. Fluid flow in a sequence of nonwelded zeolitized ash-flow or bedded tuffs and thin intervening reworked zones appears to be a porous-medium phenomenon, regardless of the presence of layering. There are no consistent differences in either bulk composition or detailed mineralogy between bedded tuffs and bed-contact zones in Tunnel Bed 5. Although the original bulk composition of Tunnel Bed 5 was probably peralkaline, extensive zeolitization has resulted in a present peraluminous bulk composition of both bedded tuffs and bed-contact zones. The major zeolite present, clinoptilolite, is intermediate (Ca:K:Na = 26:35:39) and effectively uniform in composition. This composition is similar to that of clinoptilolite from the tuffaceous beds of Calico Hills above the static water level in hole USW G-1, but somewhat different from that reported for zeolites from below the static water level in USW G-2. Tunnel Bed 5 also contains abundant hydrous manganese oxides. The similarity in composition of the clinoptilolites from Tunnel Bed 5 and those above the static water level at Yucca Mountain indicates that many of the results of nuclide-migration experiments in Tunnel Bed 5 would be transferrable to zeolitized nonwelded tuffs above the static water level at Yucca Mountain

Theoretical comparison of packed bed and fluidized bed membrane reactors for methane reforming

NARCIS (Netherlands)

Gallucci, F.; van Sint Annaland, M.; Kuipers, J.A.M.

2010-01-01

In this theoretical work the performance of different membrane reactor concepts, both fluidized bed and packed bed membrane reactors, has been compared for ultra-pure hydrogen production via methane reforming. Using detailed theoretical models, the required membrane area to reach a given conversion

Pleistocene volcanism of Bed I, Olduvai Gorge, Tanzania: chemostratigraphy, sedimentology, and paleoecology

OpenAIRE

Habermann, Jörg

2016-01-01

Chapter 2 addresses correlation difficulties in Bed I that arise from major lateral facies changes combined with discontinuous exposure using the discriminative power of the chemical composition of major juvenile mineral phases (augite, anorthoclase, plagioclase) from tuffs, volcaniclastic sandstones, siliciclastic units, and lavas. These compositions, obtained from electron probe micro-analysis, are statistically evaluated applying principal component analysis and discriminant analysis to de...

Fluid-bed process for SYNROC production

International Nuclear Information System (INIS)

Ackerman, F.J.; Grens, J.Z.; Ryerson, F.J.; Hoenig, C.L.; Bazan, F.; Peters, P.E.; Smith, R.; Campbell, J.H.

1983-01-01

SYNROC is a titanate-based ceramic waste developed for the immobilization of high-level nuclear reactor waste. Lawrence Livermore National Laboratory (LLNL) has investigated a fluid-bed technique for the large-scale production of SYNROC precursor powders. Making SYNROC in a fluid bed permits slurry drying, calcination and reduction-oxidation reactions to be carried out in a single unit. We present the results of SYNROC fluid-bed studies from two fluid-bed units 10 cm in diameter: an internally heated fluid-bed unit developed by Exxon Idaho and an externally heated unit constructed at LLNL. Bed operation over a range of temperatures, feed rates, fluidizing rates, and redox conditions indicate that SYNROC powders of a high density and a uniform particle size can be produced. These powders facilitate the densification step and yield dense ceramics (greater than 95% theoretical density) with well-developed phases and low leaching rates

Evaluation of convective heat transfer coefficient of various crops in cyclone type dryer

International Nuclear Information System (INIS)

Akpinar, E. Kavak

2005-01-01

In this paper, an attempt was made to evaluate the convective heat transfer coefficient during drying of various crops and to investigate the influences of drying air velocity and temperature on the convective heat transfer coefficient. Drying was conducted in a convective cyclone type dryer at drying air temperatures of 60, 70 and 80 deg. C and velocities of 1 and 1.5 m/s using rectangle shaped potato and apple slices (12.5 x 12.5 x 25 mm) and cylindrical shaped pumpkin slices (35 x 5 mm). The temperature changes of the dried crops and the temperature of the drying air were measured during the drying process. It was found that the values of convective heat transfer coefficient varied from crop to crop with a range 30.21406 and 20.65470 W/m 2 C for the crops studied, and it was observed that the convective heat transfer coefficient increased in large amounts with the increase of the drying air velocity but increased in small amounts with the rise of the drying air temperature

Optimizing the energy efficiency of conventional multi-cylinder dryers in the paper industry

International Nuclear Information System (INIS)

Laurijssen, Jobien; De Gram, Frans J.; Worrell, Ernst; Faaij, Andre

2010-01-01

The paper industry is, with about 6% of the total worldwide industrial energy use, an energy-intensive industry. The drying section is with approximately 50% the largest energy consumer in a paper mill, energy use in this section is mainly heat use. Several options to decrease heat use in conventional multi-cylinder drying sections are investigated, calculating the effect on energy use. Optimization measures include a) decreasing the amount of water evaporation by applying additives in higher consistencies and by lowering the water viscosity, b) decreasing the heat use of water evaporation by increasing the dew point temperature of the dryer and c) increasing the amount of heat recovery by using exhaust air to not only pre-heat the incoming air but also to increase process water temperatures. These could all be achieved by retrofitting and/or choosing different processing conditions in existing factories. The combined thermal heat saving potential due to the optimization actions is 1.3 GJ h /t paper (or 32% of the drying section's heat use) as compared to the reference situation.

Evaluation of convective heat transfer coefficient of various crops in cyclone type dryer

Energy Technology Data Exchange (ETDEWEB)

Akpinar, E. Kavak [Mechanical Engineering Department, Firat University, 23279 Elazig (Turkey)]. E-mail: eakpinar@firat.edu.tr

2005-09-15

In this paper, an attempt was made to evaluate the convective heat transfer coefficient during drying of various crops and to investigate the influences of drying air velocity and temperature on the convective heat transfer coefficient. Drying was conducted in a convective cyclone type dryer at drying air temperatures of 60, 70 and 80 deg. C and velocities of 1 and 1.5 m/s using rectangle shaped potato and apple slices (12.5 x 12.5 x 25 mm) and cylindrical shaped pumpkin slices (35 x 5 mm). The temperature changes of the dried crops and the temperature of the drying air were measured during the drying process. It was found that the values of convective heat transfer coefficient varied from crop to crop with a range 30.21406 and 20.65470 W/m{sup 2} C for the crops studied, and it was observed that the convective heat transfer coefficient increased in large amounts with the increase of the drying air velocity but increased in small amounts with the rise of the drying air temperature.

Clinical evaluation of an automated turning bed.

Science.gov (United States)

Melland, H I; Langemo, D; Hanson, D; Olson, B; Hunter, S

1999-01-01

The purposes of this study were to assess client comfort and sleep quality, client physiologic response (skin and respiratory status), the effect on the need for caregiver assistance, and cost when using an automated turning bed. Nonexperimental, evaluative study. Twenty-four adult home or long-term care resident subjects who had a degenerative disease, spinal cord injury, stroke, cerebral palsy, or back surgery. Each subject agreed to use the automated turning bed for four weeks. Researchers completed a demographic survey and skin assessment, and assessed each subject for pressure ulcer risk and for the need of assistance of a care giver for turning before and after the four weeks of using the turning bed. Subjects rated the turning bed in terms of comfort and sleep quality. Subjects rated the turning bed as more comfortable than their own bed and expressed satisfaction at the pain relief attained when on the turning bed. While using the turning bed, there was a significant improvement in sleep quality. No skin breakdown or deterioration in respiratory status occurred. Fewer subjects required the assistance of a caregiver for turning when on the turning bed. This automated turning bed shows great promise in meeting a need for patients with limited mobility whether they are homebound or in a residential community. Future studies that further investigate use of the turning bed for postoperative back patients while still in the acute care setting are indicated. Replicative studies with a larger sample size are also indicated.

Predicting fractional bed load transport rates: Application of the Wilcock‐Crowe equations to a regulated gravel bed river

Science.gov (United States)

Gaeuman, David; Andrews, E.D.; Krause, Andreas; Smith, Wes

2009-01-01

Bed load samples from four locations in the Trinity River of northern California are analyzed to evaluate the performance of the Wilcock‐Crowe bed load transport equations for predicting fractional bed load transport rates. Bed surface particles become smaller and the fraction of sand on the bed increases with distance downstream from Lewiston Dam. The dimensionless reference shear stress for the mean bed particle size (τ*rm) is largest near the dam, but varies relatively little between the more downstream locations. The relation between τ*rm and the reference shear stresses for other size fractions is constant across all locations. Total bed load transport rates predicted with the Wilcock‐Crowe equations are within a factor of 2 of sampled transport rates for 68% of all samples. The Wilcock‐Crowe equations nonetheless consistently under‐predict the transport of particles larger than 128 mm, frequently by more than an order of magnitude. Accurate prediction of the transport rates of the largest particles is important for models in which the evolution of the surface grain size distribution determines subsequent bed load transport rates. Values of τ*rm estimated from bed load samples are up to 50% larger than those predicted with the Wilcock‐Crowe equations, and sampled bed load transport approximates equal mobility across a wider range of grain sizes than is implied by the equations. Modifications to the Wilcock‐Crowe equation for determining τ*rm and the hiding function used to scale τ*rm to other grain size fractions are proposed to achieve the best fit to observed bed load transport in the Trinity River.

DNA profiling of trace DNA recovered from bedding.

Science.gov (United States)

Petricevic, Susan F; Bright, Jo-Anne; Cockerton, Sarah L

2006-05-25

Trace DNA is often detected on handled items and worn clothing examined in forensic laboratories. In this study, the potential transfer of trace DNA to bedding by normal contact, when an individual sleeps in a bed, is examined. Volunteers slept one night on a new, lower bed sheet in their own bed and one night in a bed foreign to them. Samples from the sheets were collected and analysed by DNA profiling. The results indicate that the DNA profile of an individual can be obtained from bedding after one night of sleeping in a bed. The DNA profile of the owner of the bed could also be detected in the foreign bed experiments. Since mixed DNA profiles can be obtained from trace DNA on bedding, caution should be exercised when drawing conclusions from DNA profiling results obtained from such samples. This transfer may have important repercussions in sexual assault investigations.

Utility of Recycled Bedding for Laboratory Rodents

OpenAIRE

Miyamoto, Toru; Li, Zhixia; Kibushi, Tomomi; Okano, Shinya; Yamasaki, Nakamichi; Kasai, Noriyuki

2009-01-01

Animal facilities generate a large amount of used bedding containing excrement as medical waste. We developed a recycling system for used bedding that involves soft hydrothermal processing. In this study, we examined the effects of bedding type on growth, hematologic and serum biochemical values, and organ weights of female and male mice reared on either recycled or fresh bedding from 3 to 33 wk of age. Neither growth nor physiology differed between mice housed on recycled bedding compared wi...

Bed-To-Wall Heat Transfer in a Supercritical Circulating Fluidised Bed Boiler

Directory of Open Access Journals (Sweden)

Błaszczuk Artur

2014-06-01

Full Text Available The purpose of this work is to find a correlation for heat transfer to walls in a 1296 t/h supercritical circulating fluidised bed (CFB boiler. The effect of bed-to-wall heat transfer coefficient in a long active heat transfer surface was discussed, excluding the radiation component. Experiments for four different unit loads (i.e. 100% MCR, 80% MCR, 60% MCR and 40% MCR were conducted at a constant excess air ratio and high level of bed pressure (ca. 6 kPa in each test run. The empirical correlation of the heat transfer coefficient in a large-scale CFB boiler was mainly determined by two key operating parameters, suspension density and bed temperature. Furthermore, data processing was used in order to develop empirical correlation ranges between 3.05 to 5.35 m·s-1 for gas superficial velocity, 0.25 to 0.51 for the ratio of the secondary to the primary air, 1028 to 1137K for bed temperature inside the furnace chamber of a commercial CFB boiler, and 1.20 to 553 kg·m-3 for suspension density. The suspension density was specified on the base of pressure measurements inside the boiler’s combustion chamber using pressure sensors. Pressure measurements were collected at the measuring ports situated on the front wall of the combustion chamber. The obtained correlation of the heat transfer coefficient is in agreement with the data obtained from typical industrial CFB boilers.

Bed Load Variability and Morphology of Gravel Bed Rivers Subject to Unsteady Flow: A Laboratory Investigation

Science.gov (United States)

Redolfi, M.; Bertoldi, W.; Tubino, M.; Welber, M.

2018-02-01

Measurement and estimation of bed load transport in gravel bed rivers are highly affected by its temporal fluctuations. Such variability is primarily driven by the flow regime but is also associated with a variety of inherent channel processes, such as flow turbulence, grain entrainment, and bed forms migration. These internal and external controls often act at comparable time scales, and are therefore difficult to disentangle, thus hindering the study of bed load variability under unsteady flow regime. In this paper, we report on laboratory experiments performed in a large, mobile bed flume where typical hydromorphological conditions of gravel bed rivers were reproduced. Data from a large number of replicated runs, including triangular and square-wave hydrographs, were used to build a statistically sound description of sediment transport processes. We found that the inherent variability of bed load flux strongly depends on the sampling interval, and it is significantly higher in complex, wandering or braided channels. This variability can be filtered out by computing the mean response over the experimental replicates, which allows us to highlight two distinctive phenomena: (i) an overshooting (undershooting) response of the mean bed load flux to a sudden increase (decrease) of discharge, and (ii) a clockwise hysteresis in the sediment rating curve. We then provide an interpretation of these findings through a conceptual mathematical model, showing how both phenomena are associated with a lagging morphological adaptation to unsteady flow. Overall, this work provides basic information for evaluating, monitoring, and managing gravel transport in morphologically active rivers.

Use of bed nets and factors that influence bed net use among Jinuo Ethnic Minority in southern China.

Science.gov (United States)

Xu, Jian-wei; Liao, Yuan-mei; Liu, Hui; Nie, Ren-hua; Havumaki, Joshua

2014-01-01

Insecticide-treated nets (ITNs) are an integral part of vector control recommendations for malaria elimination in China. This study investigated the extent to which bed nets were used and which factors influence bed net use among Jinuo Ethnic Minority in China-Myanmar-Laos border areas. This study combined a quantitative household questionnaire survey and qualitative semi-structured in-depth interviews (SDI). Questionnaires were administered to 352 heads of households. SDIs were given to 20 key informants. The bed net to person ratio was 1∶2.1 (i.e., nearly one net for every two people), however only 169 (48.0%) households owned at least one net and 623 (47.2%) residents slept under bed nets the prior night. The percentages of residents who regularly slept under nets (RSUN) and slept under nets the prior night (SUNPN) were similar (48.0% vs. 47.2%, P>0.05), however the percentage correct use of nets (CUN) was significantly lower (34.5%, Pcash income per person (ACIP) was an independent factor that influenced bed net use (PHigh bed net availability does not necessarily mean higher coverage or bed net use. Household income, house type and knowledge of the ability of bed nets to prevent malaria are all independent factors that influence bed net use among Jinuo Ethnic Minority.

Numerical calculation of wall-to-bed heat transfer coefficients in gas-fluidized beds

NARCIS (Netherlands)

Kuipers, J.A.M.; Prins, W.; van Swaaij, W.P.M.

1992-01-01

A computer model for a hot gas-fluidized bed has been developed. The theoretical description is based on a two-fluid model (TFM) approach in which both phases are considered to be continuous and fully interpenetrating. Local wall-to-bed heat-transfer coefficients have been calculated by the

Ash related bed agglomeration during fluidized bed combustion, further development of the classification method based on CCSEM; CCSEM-luokitusmenetelmaen jatkokehittaeminen tuhkan aiheuttaman agglomeroitumisen tutkimisessa leiju- ja kiertopetipoltossa

Energy Technology Data Exchange (ETDEWEB)

Laitinen, R; Patrikainen, T; Heikkinen, R; Tiainen, M; Virtanen, M [Oulu Univ. (Finland). Inst. of Chemistry

1997-10-01

The scope of this project is to use the information and experience gained from the development of classification method to predict ash related problems like bed agglomeration during fluidised combustion. If boilers have to be shut down due to slagging or agglomeration of the bed material may cause significant economic losses for the entire energy production chain. Mineral classification methods based on the scanning electron microscopy are commonly used for coal ash investigation. In this work different biomass, peat, and peat-wood ash, fluidised-bed materials, and bed agglomerates were analysed with SEM-EDS combined with automatic image analysis software. The properties of ash particles are different depending on the fuel type. If biomass like wood or bark are added to peat the resulting ash has different properties. Due to the low mineral content in the original peat and to the fact that the majority of inorganic material is bound to the organic matrix, the classification has turned out to be less informative than was hoped. However, good results are obtained the by use of quasiternary diagrams. With these diagrams the distribution of particle composition is easily illustrated and thus meaningful prediction can be made of the slagging and agglomerating properties of ash. The content of ten different elements are determined for each particle by SEM-EDS combined with Link AIA software. The composition of the diagram corners can be varied Freely within these ten elements. (orig.)

VA National Bed Control System

Data.gov (United States)

Department of Veterans Affairs — The VA National Bed Control System records the levels of operating, unavailable and authorized beds at each VAMC, and it tracks requests for changes in these levels....

Tritium measurement technique using ''in-bed'' calorimetry

International Nuclear Information System (INIS)

Klein, J.E.; Mallory, M.K.; Nobile, A. Jr.

1991-01-01

One of the new technologies that has been introduced to the Savannah River Site (SRS) is the production scale use of metal hydride technology to store, pump, and compress hydrogen isotopes. For tritium stored in metal hydride storage beds, a unique relationship does not exist between the amount of tritium in the bed and the pressure-volume-temperature properties of the hydride material. Determining the amount of tritium in a hydride bed after desorbing the contents of the bed to a tank and performing pressure, volume, temperature, and composition (PVTC) measurements is not practical due to long desorption/absorption times and the inability to remove tritium ''heels'' from the metal hydride materials under normal processing conditions. To eliminate the need to remove tritium from hydride storage beds for measurement purposes, and ''in-bed'' tritium calorimetric measurement technique has been developed. The steady-state temperature rise of a gas stream flowing through a jacketed metal hydride storage bed is measured and correlated with power input to electric heaters used to simulate the radiolytic power generated by the decay of tritium to 3 He. Temperature rise results for prototype metal hydride storage beds and the effects of using different gases in the bed are shown. Linear regression results shows that for 95% confidence intervals, temperature rise measurements can be obtained in 14 hours and have an accuracy of ±1.6% of a tritium filled hydride storage bed

Equilibrium modeling of gasification: Gibbs free energy minimization approach and its application to spouted bed and spout-fluid bed gasifiers

International Nuclear Information System (INIS)

Jarungthammachote, S.; Dutta, A.

2008-01-01

Spouted beds have been found in many applications, one of which is gasification. In this paper, the gasification processes of conventional and modified spouted bed gasifiers were considered. The conventional spouted bed is a central jet spouted bed, while the modified spouted beds are circular split spouted bed and spout-fluid bed. The Gibbs free energy minimization method was used to predict the composition of the producer gas. The major six components, CO, CO 2 , CH 4 , H 2 O, H 2 and N 2 , were determined in the mixture of the producer gas. The results showed that the carbon conversion in the gasification process plays an important role in the model. A modified model was developed by considering the carbon conversion in the constraint equations and in the energy balance calculation. The results from the modified model showed improvements. The higher heating values (HHV) were also calculated and compared with the ones from experiments. The agreements of the calculated and experimental values of HHV, especially in the case of the circular split spouted bed and the spout-fluid bed were observed

Adult Bed-Wetting: A Concern?

Science.gov (United States)

Adult bed-wetting: A concern? My 24-year-old husband has started to wet the bed at ... of Privacy Practices Notice of Nondiscrimination Manage Cookies Advertising Mayo Clinic is a not-for-profit organization ...

Getting Rid of Bed Bugs

Science.gov (United States)

... Directory Planning, Budget and Results Jobs and Internships Headquarters Offices Regional Offices Labs and Research Centers Bed ... to be careful in how you select a company. Related Information Collaborative Strategy on Bed Bugs - highlights ...

EPA-Registered Bed Bug Products

Science.gov (United States)

... rest or hide in hampers, bed frames, even furniture); Failing to treat adjacent areas where bed bugs ... to work (some pesticides, such as desiccators or growth regulators, may be very effective but take some ...

Control of the Bed Temperature of a Circulating Fluidized Bed Boiler by using Particle Swarm Optimization

Directory of Open Access Journals (Sweden)

AYGUN, H.

2012-05-01

Full Text Available Circulating fluidized bed boilers are increasingly used in the power generation due to their higher combustion efficiency and lower pollutant emissions. Such boilers require an effective control of the bed temperature, because it influences the boiler combustion efficiency and the rate of harmful emissions. A Particle-Swarm-Optimization-Proportional-Integrative-Derivative (PSO-PID controller for the bed temperature of a circulating fluidized bed boiler is presented. In order to prove the capability of the proposed controller, its performances are compared at different boiler loads with those of a Fuzzy Logic (FL controller. The simulation results demonstrate some advantages of the proposed controller.

Magnetic microsperules in Permian and Triassic bedded chert from Southwest Japan

OpenAIRE

Iwahashi,Junko; Yoshida,Masaru; Miono,Shigeyoshi; Santosh,Geetha; Santosh,M.

1991-01-01

Magnetic microspherules collected from the Permian and Triassic bedded cherts in Southwest Japan were studied. The size range, as estimated from 801 microspherules, vary from 3 to 100μm, with a peak size distribution between 10-20μm. Three broad shapes are recognized : spherical-, drop- and rocket-shaped, all categories including hollow particles. The surface textures as studied from scanning electron microscope show five dominant varieties : random mosaic, dendritic mosaic, feather crystal, ...

Expanded-bed chromatography in primary protein purification.

Science.gov (United States)

Anspach, F B; Curbelo, D; Hartmann, R; Garke, G; Deckwer, W D

1999-12-31

Chromatography in stable expanded beds enables proteins to be recovered directly from cultivations of microorganisms or cells and preparations of disrupted cells, without the need for prior removal of suspended solids. The general performance of an expanded bed is comparable to a packed bed owing to reduced mixing of the adsorbent particles in the column. However, optimal operating conditions are more restricted than in a packed bed due to the dependence of bed expansion on the size and density of the adsorbent particles as well as the viscosity and density of the feedstock. The feedstock composition may become the most limiting restriction owing to interactions of adsorbent particles with cell surfaces, DNA and other substances, leading to their aggregation and consequently to bed instabilities and channeling. Despite these difficulties, expanded-bed chromatography has found widespread applications in the large scale purification of proteins from mammalian cell and microbial feedstocks in industrial bioprocessing. The basics and implementation of expanded-bed chromatography, its advantages as well as problems encountered in the use of this technique for the direct extraction of proteins from unclarified feedstocks are addressed.

Fluidization quality analyzer for fluidized beds

Science.gov (United States)

Daw, C.S.; Hawk, J.A.

1995-07-25

A control loop and fluidization quality analyzer for a fluidized bed utilizes time varying pressure drop measurements. A fast-response pressure transducer measures the overall bed pressure drop, or over some segment of the bed, and the pressure drop signal is processed to produce an output voltage which changes with the degree of fluidization turbulence. 9 figs.

Fluidised bed heat exchangers

International Nuclear Information System (INIS)

Elliott, D.E.; Healey, E.M.; Roberts, A.G.

1974-01-01

Problems that have arisen during the initial stages of development of fluidised bed boilers in which heat transfer surfaces are immersed in fluidised solids are discussed. The very high heat transfer coefficients that are obtained under these conditions can be exploited to reduce the total heat transfer surface to a fraction of that in normal boilers. However, with the high heat flux levels involved, tube stressing becomes more important and it is advantageous to use smaller diameter tubes. One of the initial problems was that the pumping power absorbed by the fluidised bed appeared to be high. The relative influence of the fluidising velocity (and the corresponding bed area), tube diameter, tube spacing, heat transfer coefficient and bed temperature on pumping power and overall cost was determined. This showed the importance of close tube packing and research was undertaken to see if this would adversely affect the heat transfer coefficient. Pressure operation also reduces the pumping power. Fouling and corrosion tests in beds burning coal suggest that higher temperatures could be reached reliably and cost studies show that, provided the better refractory metals are used, the cost of achieving higher temperatures is not unduly high. It now remains to demonstrate at large scale that the proposed systems are viable and that the methods incorporated to overcome start up and part lead running problems are satisfactory. The promising role of these heat transfer techniques in other applications is briefly discussed

Suitability of locally constructed solar dryers for vegetable drying

International Nuclear Information System (INIS)

Seidu, J.M.; Tevor, W.J.; Kotei, R.; Mahama, A.A.; Amoah, R.S.

2008-01-01

Indigenous vegetables and spices are usually common and abundant during the rainy season but unfortunately, almost disappear during the dry season due to inadequate processing because of their high moisture content, poor storage and marketing facilities. A study was therefore conducted to find the possibilities of drying vegetables using locally constructed solar dryers at the Mechanisation section of the University of Education, Mampong Campus. The study was done during the months of March to September, 2004 and six designs of solar panels were used. The panels were constructed using hard wood, binding materials (nails), chicken mesh, nylon net, and black and white polythene sheets. Variations in panels resulted from the type of polythene sheet used (white, black or both), drying platform and shape of the roof. The panels with their interior lined with the black polythene sheet recorded higher temperatures than those with their bases covered with only the chicken mesh and nylon nettings. All the designs recorded higher temperatures than the ambient temperature. The drying of vegetables was observed to be faster in the panels with their drying platforms lined with the black polythene sheet than those with their bases covered with only the chicken mesh and nylon net. Appearance of the vegetables after drying in the solar panels was almost the same as before drying as compared to the open sun drying that got mouldy after drying. Those vegetables that were dried directly on the black polythene sheet however were slightly darker in colour. Solar drying with these locally constructed panels would be a better means of drying vegetables by rural folks. (au)

Solid fuel feed system for a fluidized bed

Science.gov (United States)

Jones, Brian C.

1982-01-01

A fluidized bed for the combustion of coal, with limestone, is replenished with crushed coal from a system discharging the coal laterally from a station below the surface level of the bed. A compartment, or feed box, is mounted at one side of the bed and its interior separated from the bed by a weir plate beneath which the coal flows laterally into the bed while bed material is received into the compartment above the plate to maintain a predetermined minimum level of material in the compartment.

Effect of sudden addition of PCE and bioreactor coupling to ZVI filters on performance of fluidized bed bioreactors operated in simultaneous electron acceptor modes.

Science.gov (United States)

Moreno-Medina, C U; Poggi-Varaldo, Hector M; Breton-Deval, L; Rinderknecht-Seijas, N

2017-11-01

The present work evaluated the effects of (i) feeding a water contaminated with 80 mg/L PCE to bioreactors seeded with inoculum not acclimated to PCE, (ii) coupling ZVI side filters to bioreactors, and (iii) working in different biological regimes, i.e., simultaneous methanogenic aeration and simultaneous methanogenic-denitrifying regimes, on fluidized bed bioreactor performance. Simultaneous electron acceptors refer to the simultaneous presence of two compounds operating as final electron acceptors in the biological respiratory chain (e.g., use of either O 2 or NO 3 - in combination with a methanogenic environment) in a bioreactor or environmental niche. Four lab-scale, mesophilic, fluidized bed bioreactors (bioreactors) were implemented. Two bioreactors were operated as simultaneous methanogenic-denitrifying (MD) units, whereas the other two were operated in partially aerated methanogenic (PAM) mode. In the first period, all bioreactors received a wastewater with 1 g chemical oxygen demand of methanol per liter (COD-methanol/L). In a second period, all the bioreactors received the wastewater plus 80 mg perchloroethylene (PCE)/L; at the start of period 2, one MD and one PAM were coupled to side sand-zero valent iron filters (ZVI). All bioreactors were inoculated with a microbial consortium not acclimated to PCE. In this work, the performance of the full period 1 and the first 60 days of period 2 is reported and discussed. The COD removal efficiency and the nitrate removal efficiency of the bioreactors essentially did not change between period 1 and period 2, i.e., upon PCE addition. On the contrary, specific methanogenic activity in PAM bioreactors (both with and without coupled ZVI filter) significantly decreased. This was consistent with a sharp fall of methane productivity in those bioreactors in period 2. During period 2, PCE removals in the range 86 to 97 % were generally observed; the highest removal corresponded to PAM bioreactors along with the

Combustion of peanut shells in a cone-shaped bubbling fluidized-bed combustor using alumina as the bed material

International Nuclear Information System (INIS)

Arromdee, Porametr; Kuprianov, Vladimir I.

2012-01-01

Highlights: ► We propose burning of peanut shells in a conical fluidized bed using alumina sand. ► We examine hydrodynamic, combustion and emission characteristics of the reactor. ► High, over 99%, combustion efficiency is achievable. ► Emissions of CO and NO from the combustor meet the national emission limits. ► Composition of the bed material undergoes significant changes during the combustion. -- Abstract: This paper reports experimental studies on burning peanut shells in the conical fluidized-bed combustor using alumina sand as the fluidizing agent. Prior to combustion tests, hydrodynamic regimes and characteristics of a conical alumina–biomass bed were investigated under cold-state conditions for variable percentage of peanut shells in the mixture and static bed height. With selected particle sizes (300–500 μm) and static bed height (30 cm), alumina ensured bubbling fluidization regime of the bed at operating conditions specified for firing biomass. Combustion tests were performed at 60 kg/h and 45 kg/h fuel feed rates, while ranging excess air from 20% to 80% at a fixed combustor load. Temperature and gas concentrations (O 2 , CO, C x H y as CH 4 , and NO) were measured along radial and axial directions inside the reactor as well as at stack in order to characterize combustion and emission performance of the combustor for the ranges of operating conditions. For firing 60 kg/h peanut shells, excess air of 40% can be selected as an appropriate value ensuring high, about 99%, combustion efficiency and rather low emissions of CO and NO: 520 ppm and 125 ppm, respectively (both on a dry basis and at 6% O 2 ). With reducing combustor load, the combustion efficiency and emission characteristics were improved to a little extent. No evidence of bed agglomeration was found during 30-h combustion tests on this conical fluidized-bed combustor using alumina sand as the bed material. However, the timescale effect on the composition of the bed material was

An investigation of the physical and chemical changes occuring in a Fischer-Tropsch fixed bed catalyst during hydrocarbon synthesis

International Nuclear Information System (INIS)

Duvenhage, D.J.

1990-01-01

Deactivation studies: making use of fixed bed reactors, wet chemical analysis, surface area, pore volume determinations and X-ray diffraction spectrometry, scanning electron microscope spectrometry and secondary ion mass spectrometry techniques; were performed on a low temperature iron Fischer-Tropsch catalyst. It was revealed that this catalyst is mainly deactivated by sulphur poisoning, oxidation of the catalytic reactive phases, sintering of the iron crystallites and to a lesser extent deactivation through fouling of the catalytic surface by carbonaceous deposits. It was found that the top entry section of the catalyst bed deactivated relatively fast, the bottom exit section also deactivated, but not as fast as the top section. The central portion of the catalyst bed was least affected. Sulphur contaminants in the feed gas, even though present in only minute quantities, results in a loss of catalyst performance of the top section of the catalyst bed, while water, produced as a product from the Fischer-Tropsch reaction, oxidized and sintered the catalyst over the bottom section of the catalyst bed. 88 figs., 7 tabs., 224 refs

Coolability of volumetrically heated particle beds

Energy Technology Data Exchange (ETDEWEB)

Rashid, Muhammad

2017-03-22

In case of a severe nuclear reactor accident, with loss of coolant, a particle bed may be formed from the fragmentation of the molten core in the residual water at different stages of the accident. To avoid further propagation of the accident and maintain the integrity of the reactor pressure vessel, the decay heat of the particle bed must be removed. To better understand the various thermo-hydraulic processes within such heat-generating particle beds, the existing DEBRIS test facility at IKE has been modified to be able to perform novel boiling, dryout and quenching experiments. The essential experimental data includes the pressure gradients measured by 8 differential pressure transducers along the bed height as a function of liquid and vapour superficial velocities, the determination of local dryout heat fluxes for different system pressures as well as the local temperature distribution measured by a set of 51 thermocouples installed inside the particle bed. The experiments were carried out for two different particle beds: a polydispersed particle bed which consisted of stainless steel balls (2 mm, 3 mm and 6 mm diameters) and an irregular particle bed which consisted of a mixture of steel balls (3 mm and 6 mm) and irregularly shaped Al{sub 2}O{sub 3} particles. Additionally, all experiments were carried out for different flow conditions, such as the reference case of passive 1D top-flooding, 1D bottom flooding (driven by external pumps and different downcomer configurations) and 2D top-/bottom-/lateral flooding with a perforated downcomer. In this work, it has been observed that for both particle beds with downcomer configurations an open downcomer leads to the best coolability (dryout heat flux = 1560 kW/m{sup 2}, polydispersed particle bed, psys = 1 bar) of the particle bed, mainly due to bottom-flow with enhanced natural convection. It has also been shown that a potential lateral flow via a perforation of the downcomer does not bring any further improvements

Coolability of volumetrically heated particle beds

International Nuclear Information System (INIS)

Rashid, Muhammad

2017-01-01

In case of a severe nuclear reactor accident, with loss of coolant, a particle bed may be formed from the fragmentation of the molten core in the residual water at different stages of the accident. To avoid further propagation of the accident and maintain the integrity of the reactor pressure vessel, the decay heat of the particle bed must be removed. To better understand the various thermo-hydraulic processes within such heat-generating particle beds, the existing DEBRIS test facility at IKE has been modified to be able to perform novel boiling, dryout and quenching experiments. The essential experimental data includes the pressure gradients measured by 8 differential pressure transducers along the bed height as a function of liquid and vapour superficial velocities, the determination of local dryout heat fluxes for different system pressures as well as the local temperature distribution measured by a set of 51 thermocouples installed inside the particle bed. The experiments were carried out for two different particle beds: a polydispersed particle bed which consisted of stainless steel balls (2 mm, 3 mm and 6 mm diameters) and an irregular particle bed which consisted of a mixture of steel balls (3 mm and 6 mm) and irregularly shaped Al 2 O 3 particles. Additionally, all experiments were carried out for different flow conditions, such as the reference case of passive 1D top-flooding, 1D bottom flooding (driven by external pumps and different downcomer configurations) and 2D top-/bottom-/lateral flooding with a perforated downcomer. In this work, it has been observed that for both particle beds with downcomer configurations an open downcomer leads to the best coolability (dryout heat flux = 1560 kW/m 2 , polydispersed particle bed, psys = 1 bar) of the particle bed, mainly due to bottom-flow with enhanced natural convection. It has also been shown that a potential lateral flow via a perforation of the downcomer does not bring any further improvements in

Flow characteristics of counter-current flow in debris bed

International Nuclear Information System (INIS)

Abe, Yutaka; Adachi, Hiromichi

2004-01-01

In the course of a severe accident, a damaged core would form a debris bed consisting of once-molten and fragmented fuel elements. It is necessary to evaluate the dryout heat flux for the judgment of the coolability of the debris bed during the severe accident. The dryout phenomena in the debris bed is dominated by the counter-current flow limitation (CCFL) in the debris bed. In this study, air-water counter-current flow behavior in the debris bed is experimentally investigated with glass particles simulating the debris beds. In this experiment, falling water flow rate and axial pressure distributions were experimentally measured. As the results, it is clarified that falling water flow rate becomes larger with the debris bed height and the pressure gradient in the upper region of the debris bed is different from that in the lower region of the debris bed. These results indicate that the dominant region for CCFL in the debris bed is identified near the top of the debris bed. Analytical results with annular flow model indicates that interfacial shear stress in the upper region of the debris bed is larger than that in the lower region of the debris bed. (author)

Effects of two types of dryer on ADU and UO2 pellet manufacture

International Nuclear Information System (INIS)

Wu Zhiming; He Zhengjie

1995-05-01

The concepts of spray drying process and pebble-bed fluidized drying process for ADU slurry is presented. And the effects of ADU powder and UO 2 powder/pellet by these processes using the statistic results from series production are discussed. It is believed that these drying methods have no influence on structure and shape of ADU particle, and thereby no difference will be made to the properties of UO 2 powder and pellet. Thus, spray drying process can really be replaced by pebble-bed fluidized drying process. (10 figs., 6 tabs.)

Fluidized-bed nuclear reactor

International Nuclear Information System (INIS)

Grimmett, E.S.; Kunze, J.F.

1975-01-01

A reactor vessel containing a fluidized-bed region of particulate material including both a neutron-moderating and a fertile substance is described. A gas flow including fissile material passes through the vessel at a sufficient rate to fluidize the particulate material and at a sufficient density to support a thermal fission reaction within the fluidized-bed region. The high-temperature portion of a heat transfer system is located within the fluidized-bed region of the reactor vessel in direct contact with the fluidized particles. Heat released by fission is thereby transferred at an enhanced rate to a coolant circulating within the heat transfer system. Fission products are continuously removed from the gas flow and supplemental fissile material added during the reactor operation. (U.S.)

Tritium removal from air streams by catalytic oxidation and water adsorption

International Nuclear Information System (INIS)

Sherwood, A.E.

1976-06-01

An effective method of capturing tritium from air streams is by catalytic oxidation followed by water adsorption on a microporous solid adsorbent. Performance of a burner/dryer combination is illustrated by overall mass balance equations. Engineering design methods for packed bed reactors and adsorbers are reviewed, emphasizing the experimental data needed for design and the effect of operating conditions on system performance

2D numerical model of particle-bed collision in fluid-particle flows over bed

Czech Academy of Sciences Publication Activity Database

Lukerchenko, Nikolay; Chára, Zdeněk; Vlasák, Pavel

2006-01-01

Roč. 44, č. 1 (2006), s. 70-78 ISSN 0022-1686 R&D Projects: GA AV ČR IAA2060201 Institutional research plan: CEZ:AV0Z20600510 Keywords : saltation * particle-bed collision * collision angle * bed roughness Subject RIV: BK - Fluid Dynamics Impact factor: 0.527, year: 2006

Fluidized-bed reactors processes and operating conditions

CERN Document Server

Yates, John G

2016-01-01

The fluidized-bed reactor is the centerpiece of industrial fluidization processes. This book focuses on the design and operation of fluidized beds in many different industrial processes, emphasizing the rationale for choosing fluidized beds for each particular process. The book starts with a brief history of fluidization from its inception in the 1940’s. The authors present both the fluid dynamics of gas-solid fluidized beds and the extensive experimental studies of operating systems and they set them in the context of operating processes that use fluid-bed reactors. Chemical engineering students and postdocs as well as practicing engineers will find great interest in this book.

Vibro-fluidized bed heat pump drying of mint leaves with respect to phenolic content, antioxidant activity, and color indices

Directory of Open Access Journals (Sweden)

Ataei Ardestani Seyed Majid

2015-01-01

Full Text Available Because of high porosity and stickiness of mint leaves, they could not be fluidized well during fluidization. In this study, a vibro-fluidized bed dryer assisted heat pump system was designed and fabricated to overcome this problem. The drying experiments were carried out at temperatures of 40, 50 and 60 °C. The quality of the dehydrated samples was assessed based on color indices, antioxidant activity, and total phenolic content. Drying process primarily occurred in falling rate period. The effective coefficient of moisture transfer of the samples was increased with air temperature and varied from 4.26656×10-11 to 2.95872×10-10 m2 s-1 for heat pump drying (HPD method, and 3.71918×10-11 to 1.29196×10-10 m2 s-1 for none-heat pump drying (NHPD method. The color indices for temperatures of 40 and 50 °C were very close to each other, whereas by increasing temperature to 60 °C, a remarkable loss of green color was observed. The highest phenolic content was found in methanolic extract for HPD at 60 °C, and NHPD at 50 °C contained the lowest amount of phenolic compounds. NHPD treatments showed lower antioxidant activity compared to HPD treatments at the same temperature due to the longer drying times.

Effect of various drying bed on thermodynamic characteristics

Directory of Open Access Journals (Sweden)

Ali Motevali

2017-09-01

Full Text Available In this study thermodynamic parameter and energy consumption in drying of two plant dill and mint in three bed drying including fix, semi fix and fluid with using a hot air drying was investigated. Experimental was conducted in three bed drying including fix, semi fix and fluid and four levels temperature (30, 40, 50 and 60 °C. Maximum energy consumption in dill drying at 40 °C and fluid bed to be 16.41 MJ and minimum energy consumption at 30 °C and fix bed to be 2.77 MJ. Also minimum energy consumption in mint drying at 60 °C and fix bed to be 3.64 MJ and maximum energy consumption at 40 °C and fluid bed to be 28.65 MJ. The highest energy, drying and thermal efficiency for both mint and dill was achieved at 60 °C on the fixed bed, whereas the lowest efficiency was at 40 °C and on the fluidized bed. Also the highest power and specific heat consumption for both mint and dill was achieved at 40 °C on the fluid bed, whereas the lowest efficiency was at 30 °C and on the fluidized bed.

Fluidized bed dry dense medium coal beneficiation

CSIR Research Space (South Africa)

North, Brian C

2017-10-01

Full Text Available medium beneficiation using a fluidized bed was investigated. Bed materials of sand, magnetite and ilmenite were used in a laboratory sized cylindrical fluidized bed. The materials were individually tested, as were mixes of sand and heavy minerals. Coal...

Estudo de viabilidade da secagem da biomassa da banana verde em spray dryer rotativo

Directory of Open Access Journals (Sweden)

Ricardo Kenji Oi

2010-01-01

Full Text Available This paper presents a technical feasibility study for drying the biomass of green bananas at a pilot plant spray dryer with rotary atomizer. The biomass of the green banana is a component that can be used industrially in a wide variety of foods, with functional properties, especially the presence of resistant starch. The variables selected in the experimental procedure were the biomass concentration of green banana, feed flow rate and rotation of the atomizer. Responses were obtained as the mass and relative humidity of the dried product. Three levels were used in selected variables, which corresponded to the completion of 27 experiments. In experiments in which they obtained the lowest values of relative humidity, the amounts of mass were also the lowest, while in experiments where they met the higher amounts of the levels of relative humidity ranged from the highest. Considering the industrial application, whose purpose is the low humidity and increased production of the product, test 22 was the most appropriate, and found 11% moisture and 4.33 g in mass.

Aging of control and service air compressors and dryers used in nuclear power plants

International Nuclear Information System (INIS)

Moyers, J.C.

1990-07-01

This report was produced under the Detection of Defects and Degradation Monitoring of Nuclear Plant Safety Equipment element of the Nuclear Plant Aging Research Program. This element includes the identification of practical and cost-effective methods for detecting, monitoring, and assessing the severity of time-dependent degradation (aging) of control and service air compressors and dryers in nuclear power plants. These methods are to provide capabilities for establishing degradation trends prior to failure and developing guidance for effective maintenance. The topics of this Phase 1 assessment report are failure modes and causes resulting from aging, manufacturer--recommended maintenance and surveillance practices, and measurable parameters (including functional indicators) for use in assessing operational readiness, establishing degradation trends, and detecting incipient failure. the results presented are based on information derived from operating experience records, manufacturer-supplied information, and input from plant operators. For each failure mode, failure causes are listed by subcomponent, and parameters potentially useful for detecting degradation that could lead to failure are identified. 13 refs., 9 figs., 16 tabs

Effectiveness of Bed Bug Pesticides

Science.gov (United States)

Before EPA allows a bed bug claim on a label, the product must be supported by data showing it will kill bed bugs when applied according to the label. Also consider factors such as extent of infestation, site preparation, and insect life stages.

Characterization of drying parameters for solid fuels; Kiinteiden polttoaineiden kuivumis-parametrien karakterisointi

Energy Technology Data Exchange (ETDEWEB)

Impola, R; Saastamoinen, J [VTT Energy, Jyvaeskylae (Finland); Fagernaes, L [VTT Energy, Espoo (Finland)

1997-12-01

Drying of solid fuel particles in hot gases (50 - 200 deg C) is studied both theoretically and experimentally. The measurements are carried out by using a thermobalance reactor constructed for drying and pyrolysis studies of particles up to 30 mm by diameter. The model is based on the solution of the conservation equations for mass and energy. The main parameters affecting the drying rate are: particle size, particle shape, initial particle moisture content, gas temperature and gas moisture content, temperature of the reactor walls and slip velocity. Also, the drying of biomass fuel particles in fixed and moving beds with hot gas or steam is considered both experimentally and theoretically. A single particle drying model is coupled with a model describing heat and moisture transfer in the gas phase of the bed. The model can be used in the dimensioning of the drying system in a larger scale. Other study subjects were the movement of wood and peat particles in a pneumatic dryer, and the drying of a single fuel particle in steam under various pressures. The aim of the research work was to present a review of recent studies on emissions from biomass drying. The work covers the emissions from different feedstocks, and from different dryers and drying tests (atmospheric, pressurised, flue gas and steam drying), and the effects of factors, such as feedstock, dryer type and drying conditions, on the emissions. The formation and effects of the emissions, and methods to reduce them are also discussed

Response of bed mobility to sediment supply in natural gravel bed channels: A detailed examination and evaluation of mobility parameters

Science.gov (United States)

T. E. Lisle; J. M. Nelson; B. L. Barkett; J. Pitlick; M. A. Madej

1998-01-01

Recent laboratory experiments have shown that bed mobility in gravel bed channels responds to changes in sediment supply, but detailed examinations of this adjustment in natural channels have been lacking, and practical methodologies to measure bed mobility have not been tested. We examined six gravel-bed, alternate-bar channels which have a wide range in annual...

Torsion testing of bed joints

DEFF Research Database (Denmark)

Hansen, Klavs Feilberg; Pedersen, Carsten Mørk

2008-01-01

This paper describes a simple test method for determining the torsion strength of a single bed joint between two bricks and presents results from testing using this test method. The setup for the torsion test is well defined, require minimal preparation of the test specimen and the test can...... be carried out directly in a normal testing machine. The torsion strength is believed to be the most important parameter in out-of-plane resistance of masonry walls subjected to bending about an axis perpendicular to the bed joints. The paper also contains a few test results from bending of small walls about...... an axis perpendicular to the bed joints, which indicate the close connection between these results and results from torsion tests. These characteristics make the torsion strength well suited to act as substitute parameter for the bending strength of masonry about an axis perpendicular to the bed joints....

Unsteady void measurements within debris beds using high speed X-ray tomography

Energy Technology Data Exchange (ETDEWEB)

Laurien, E., E-mail: Laurien@ike.uni-stuttgart.de; Stürzel, T., E-mail: thilo.stuerzel@stihl.de; Zhou, M., E-mail: mi.zhou@ike.uni-stuttgart.de

2017-02-15

Highlights: • A high speed X-ray tomography facility has been built for the investigation on two-phase flow. • The two-phase flow through beds of packed plastic spheres has been investigated in the facility. • 3D-reconstructions from the measurements show the fluxes in the two-phase flow. • The gas fraction has been calculated from the reconstruction and used for validation of the modeling. • A new bed with closest regular spheres arrangement has been manufactured by 3D-plotter and used in the measurement. - Abstract: Two-phase flow and boiling within debris beds representing a destroyed reactor core after a severe accident with core fragmentation can be simulated by using the porous media approach. In this approach, a local pressure drop and the heat transfer between the solid debris particles and the two-phase flow is modelled with the help flow-pattern maps, in which the boundaries between bubbly, slug, and annular flow are assumed. In order to support further understanding of these flows we have developed a very fast X-ray measurement device to visualize the 3D-void distribution within particle beds or porous media, which are otherwise un-accessible internally. The experimental setup uses a scanned electron beam directed in circles on a tungsten target to generate the X-rays. The particle bed, which has a diameter of 70 mm, is located between this target and a field of 256 X-ray detectors, which are arranged on a circle concentric to the target. The void distribution is reconstructed numerically from the attenuation of signals, which penetrates the particle bed and the two-phase flow inside. A 3D frame rate of up to 1000 Hz can be reached. The spatial resolution is such that bubbles with a diameter > 1.7 mm can be detected. We have investigated two-phase flows air/water through beds of packed plastic spheres (diameter between 3 and 15 mm) as well as through plastic beds, which were manufactured using a ‘3D-plotter’. Flow patterns can be

A low tritium hydride bed inventory estimation technique

Energy Technology Data Exchange (ETDEWEB)

Klein, J.E.; Shanahan, K.L.; Baker, R.A. [Savannah River National Laboratory, Aiken, SC (United States); Foster, P.J. [Savannah River Nuclear Solutions, Aiken, SC (United States)

2015-03-15

Low tritium hydride beds were developed and deployed into tritium service in Savannah River Site. Process beds to be used for low concentration tritium gas were not fitted with instrumentation to perform the steady-state, flowing gas calorimetric inventory measurement method. Low tritium beds contain less than the detection limit of the IBA (In-Bed Accountability) technique used for tritium inventory. This paper describes two techniques for estimating tritium content and uncertainty for low tritium content beds to be used in the facility's physical inventory (PI). PI are performed periodically to assess the quantity of nuclear material used in a facility. The first approach (Mid-point approximation method - MPA) assumes the bed is half-full and uses a gas composition measurement to estimate the tritium inventory and uncertainty. The second approach utilizes the bed's hydride material pressure-composition-temperature (PCT) properties and a gas composition measurement to reduce the uncertainty in the calculated bed inventory.

Semi-dry flue gas desulfurization using Ca(OH)2 in a fluidized bed reactor with bed materials

International Nuclear Information System (INIS)

Park, Young Oak; Roh, Hak Jae; Oh, Chang Sup; Kim, Yong Ha

2010-01-01

The main objective of present work is to reduce sulfur dioxide emission from power plant for the environment protection. The fluidized bed (FB) was used as the reactor with bed materials in a new semi-dry flue gas desulfurization (FGD) process to achieve high desulfurization efficiency (>98%). Fine powder of Ca(OH) 2 as sorbent and water were continuously fed separately to the bed reactor where bed materials (2 mm glass beads) were fluidized vigorously with flue gas (flow 720 Nm 3 / hr) using bench scale plant of stainless steel column. We have investigated different effects of water injection flow rate, Ca/ S molar ratio and weight of bed materials on SO 2 removal. The increments in the Ca/ S molar ratio and water injection flow rate have been resulted higher desulfurization efficiency with certain disadvantages such as higher sorbent cost and lower temperature of the treated flue gas, respectively. (author)

Investigation of the suspected presence of solid hydrocarbon in bedded salt samples from the Palo Duro Basin, Texas

International Nuclear Information System (INIS)

1985-10-01

This report contains laboratory test results for two bedded salt samples from the Grabbe No. 1 (PD-2) Well of the Palo Duro Basin, Texas. This study was commissioned to determine whether or not solid hydrocarbons exist in bedded salt samples in the Palo Duro Basin. Laboratory investigations include electron microprobe examinations on polished thin sections and optical examinations and chemical tests on insoluble residues of the salt samples. No direct evidence was found that identifiable solid hydrocarbons are present in either sample of the bedded salt core. The total carbon content of the two salt samples was measured yielding 0.016 and 0.022 weight percent carbon. Detailed microscopic analyses showed that the carbon in the samples was associated with calcite, clays, and the epoxy resin used in sample preparation

Does Bedding Affect the Airway and Allergy?

Directory of Open Access Journals (Sweden)

RW Siebers

2011-03-01

Full Text Available Various cross-sectional and longitudinal studies have suggested that synthetic bedding is associated with asthma, allergic rhinitis and eczema while feather bedding seems to be protective. Synthetic bedding items have higher house dust mite allergen levels than feather bedding items. This is possibly the mechanism involved although fungal and bacterial proinflammatory compounds and volatile organic compounds may play a role. In this review we present and discuss the epidemiological evidence and suggest possible mechanisms. Primary intervention studies are required to show whether feather bedding is protective for the development of childhood asthma and allergic diseases while secondary intervention studies are required to potentially reduce symptoms and medication use in subjects with established disease.

Does bedding affect the airway and allergy?

Science.gov (United States)

Siebers, R W; Crane, J

2011-04-01

Various cross-sectional and longitudinal studies have suggested that synthetic bedding is associated with asthma, allergic rhinitis and eczema while feather bedding seems to be protective. Synthetic bedding items have higher house dust mite allergen levels than feather bedding items. This is possibly the mechanism involved although fungal and bacterial proinflammatory compounds and volatile organic compounds may play a role. In this review we present and discuss the epidemiological evidence and suggest possible mechanisms. Primary intervention studies are required to show whether feather bedding is protective for the development of childhood asthma and allergic diseases while secondary intervention studies are required to potentially reduce symptoms and medication use in subjects with established disease.

Comparative study between fluidized bed and fixed bed reactors in methane reforming with CO2 and O2 to produce syngas

International Nuclear Information System (INIS)

Jing Qiangshan; Lou Hui; Mo Liuye; Zheng Xiaoming

2006-01-01

Reforming of methane with carbon dioxide and oxygen was investigated over Ni/MgO-SiO 2 catalysts using fixed bed and fluidized bed reactors. The conversions of CH 4 and CO 2 in a fluidized bed reactor were close to thermodynamic equilibrium. The activity and stability of the catalyst in the fixed bed reactor were lower than that in the fluidized bed reactor due to carbon deposition and nickel sintering. TGA and TEM techniques were used to characterize the spent catalysts. The results showed that a lot of whisker carbon was found on the catalyst in the rear of the fixed bed reactor, and no deposited carbon was observed on the catalysts in the fluidized bed reactor after reaction. It is suggested that this phenomenon is related to a permanent circulation of catalyst particles between the oxygen rich and oxygen free zones. That is, fluidization of the catalysts in the fluidized bed reactor favors inhibiting deposited carbon and thermal uniformity in the reactor

Transient quenching of superheated debris beds during bottom reflood

International Nuclear Information System (INIS)

Tutu, N.K.; Ginsberg, T.; Klein, J.; Schwarz, C.E.; Klages, J.

1984-01-01

The experimental data suggest that for small liquid supply rate and low initial particle temperature, the bed quench process is a one-dimensional frontal phenomenon. The bed heat flux is constant during most of the duration of the quench period. The range of conditions which display one-dimensional frontal cooling characteristics is identified as the deep bed regime of bed quenching, and a limiting mathematical model was developed to describe the observed behavior. For large liquid supply rate and high initial bed temperature, the bed quench process is a complex phenomenon. Under these conditions, the bed heat flux displays a nonuniform time dependence. In order to characterize this shallow bed regime, it was necessary to develop a detailed transient model of the coolant-debris interaction. This model, while developed for the shallow bed regime, also applies to the deep bed regime. Numerical computations clearly demonstrate the importance of developing a general reliable model for the solid-fluid heat transfer coefficients

The Importance of Splat Events to the Spatiotemporal Structure of Near-Bed Fluid Velocity and Bed Load Motion Over Bed Forms: Laboratory Experiments Downstream of a Backward Facing Step

Science.gov (United States)

Leary, K. C. P.; Schmeeckle, M. W.

2017-12-01

Flow separation/reattachment on the lee side of alluvial bed forms is known to produce a complex turbulence field, but the spatiotemporal details of the associated patterns of bed load sediment transported remain largely unknown. Here we report turbulence-resolving, simultaneous measurements of bed load motion and near-bed fluid velocity downstream of a backward facing step in a laboratory flume. Two synchronized high-speed video cameras simultaneously observed bed load motion and the motion of neutrally buoyant particles in a laser light sheet 6 mm above the bed at 250 frames/s downstream of a 3.8 cm backward facing step. Particle Imaging Velocimetry (PIV) and Acoustic Doppler Velocimetry (ADV) were used to characterize fluid turbulent patterns, while manual particle tracking techniques were used to characterize bed load transport. Octant analysis, conducted using ADV data, coupled with Markovian sequence probability analysis highlights differences in the flow near reattachment versus farther downstream. Near reattachment, three distinct flow patterns are apparent. Farther downstream we see the development of a dominant flow sequence. Localized, intermittent, high-magnitude transport events are more apparent near flow reattachment. These events are composed of streamwise and cross-stream fluxes of comparable magnitudes. Transport pattern and fluid velocity data are consistent with the existence of permeable "splat events," wherein a volume of fluid moves toward and impinges on the bed (sweep) causing a radial movement of fluid in all directions around the point of impingement (outward interaction). This is congruent with flow patterns, identified with octant analysis, proximal to flow reattachment.

Effects of long-duration bed rest on structural compartments of m. soleus in man

Science.gov (United States)

Belozerova, I.; Shenkman, B.; Mazin, M.; Leblanc, A.; LeBlanc, A. D. (Principal Investigator)

2001-01-01

Magnetic resonance imaging (MRI), histomorphometry and electron microscopy of muscle demonstrate that long-term exposure to actual or simulated weightlessness (including head down bed rest) leads to decreased volume of antigravity muscles in mammals. In muscles interbundle space is occupied by the connective tissue. Rat studies show that hindlimb unloading induces muscle fiber atrophy along with increase in muscle non-fiber connective tissue compartment. Beside that, usually 20% of the muscle fiber volume is comprised by non-contractile (non-myofibrillar) compartment. The aim of the present study was to compare changes in muscle volume, and in muscle fiber size with alterations in myofibrillar apparatus, and in connective tissue compartment in human m. soleus under conditions of 120 day long head down bed rest (HDBR).

Fluid-bed methane proposed

Energy Technology Data Exchange (ETDEWEB)

1981-05-01

The first full scale plant for the production of methane from organic waste could be built in the next few years believes M.J. Nyns of the University of Louvain, Belgium, utilizing either expanded bed or fluidised bed systems, with more than one stage, in a continuous flow arrangement. Up to 8.0 m cubed gas/m cubed digester/day could be produced with residence times reduced to 34 hours.

Thermomechanical interactions of particle bed-structural wall in a layered configuration. Pt. 1. Effect of particle bed thermal expansions

International Nuclear Information System (INIS)

Tehranian, F.

1995-01-01

Materials in the form of particle beds have been considered for shielding and tritium breeding as well as neutron multiplication in many of the conceptual reactor design studies. As the level of effort of the fusion blanket community in the area of out-of-pile and in-pile (ITER) testing of integrated test modules increases, so does the need for modelling capability for predicting the thermomechanical responses of the test modules under reactor environment.In this study, the thermomechanical responses of a particle bed-structural wall system in a layered configuration, subjected to bed temperature rise and/or external coolant pressure, were considered. Equations were derived which represent the dependence of the particle-to-particle and particle-to-wall contact forces and areas on the structural wall deformations and in turn on the thermomechanical loads. Using the derived equations, parametric analyses were performed to study the variations in the thermomechanical response quantities of a beryllium particle bed-stainless steel structural wall when subjected to thermomechanical loads. The results are presented in two parts. In Part I, presented in this paper, the derivation of the analytical equations and the effects of bed temperature rise are discussed. In Part II of this study, also presented in this symposium, the effects of external coolant pressure as well as the combined effects of bed temperature rise and coolant pressure on the thermomechanical responses are given.It is shown that, depending on the stiffness of the structural walls, uniform bed temperature rises in the range 100-400 C result in non-uniform effective thermal properties through the prticle bed and could increase the bed effective thermal conductivity by a factor of 2-5 and the bed-wall interface thermal conductance by even a larger factor. (orig.)

Design and performance of a Nafion dryer for continuous operation at CO₂ and CH₄ air monitoring sites

OpenAIRE

W. Paplawsky; R. F. Weiss; R. F. Keeling; L. R. Welp; S. Heckman

2012-01-01

In preparation for routine deployment in a network of greenhouse gas monitoring stations, we have designed and tested a simple method for drying ambient air to near or below 0.2% (2000 ppm) mole fraction H2O using a Nafion dryer. The inlet system was designed for use with cavity ring-down spectrometer (CRDS) analyzers such as the Picarro model G2301 that measure H2O in addition to their principal analytes, in this case CO2 and CH4. These analyzers report dry-gas mixing ratio...

Estimativa das propriedades térmicas efetivas de grãos em um secador de leito fixo Estimation of effective grain thermal properties in a fixed bed dryer

Directory of Open Access Journals (Sweden)

L. V. Fregolente

2004-06-01

Full Text Available A secagem de grãos em leito fixo é um processo complexo, ocorrendo simultaneamente a transferência de calor e de massa, dificultando a estimativa dos parâmetros térmicos efetivos, pois estes podem sofrer variações significativas no decorrer da secagem em função de alterações no teor de umidade. Neste trabalho, este problema foi contornado estimando-se os parâmetros térmicos efetivos no final da secagem, quando o teor de umidade dos grãos que compõem o leito alcança valores de equilíbrio, deixando de existir a transferência de massa, persistindo apenas a transferência de calor em regime permanente. Nestas condições, o leito possui um teor de umidade constante e a estimativa dos parâmetros térmicos efetivos pode ser efetuada a partir do ajuste de um modelo pseudo-homogêneo bidimensional estático à várias medidas de temperatura no leito de grãos no final da secagem. Os resultados indicam que a estratégia utilizada para estimativa da condutividade térmica efetiva radial e do coeficiente efetivo de transferência de calor parede-leito foi adequada. Além do que, constatou-se que dentre os grãos estudados - soja, feijão, milho e trigo - a soja apresenta os menores valores de condutividade efetiva radial, enquanto o trigo apresenta o maior valor do coeficiente de transferência de calor parede-leito.Fixed bed grain drying is a complex process, where mass and heat transfer occur simultaneously, complicating the estimation of the effective thermal parameters, because they can go through significant variations along the drying process, due to moisture content variations. In this work, this problem was avoided by estimating the effective thermal parameters at the end of the drying process, when the grain moisture content reaches equilibrium, and mass transfer stops, persisting only the steady state heat transfer. In these conditions, the bed has a constant moisture content and the estimation of the effective thermal

Better backs by better beds?

DEFF Research Database (Denmark)

Bergholdt, Kim; Fabricius, Rasmus N; Bendix, Tom

2008-01-01

mattresses have a positive effect on LBP, and especially a hard mattress is commonly believed to have a positive effect. METHODS: One hundred sixty CLBP patients were randomized to 1 of 3 groups, having a mattress/bed mounted in their sleeping room for 1 month. The beds were: (1) waterbed (Akva), (2) body......-conforming foam mattress (Tempur), and (3) a hard mattress (Innovation Futon). At baseline and after 4 weeks, a blinded observer interviewed the patients on LBP levels (0-10), daily function (activities of daily living, 0-30), and on the amount of sleeping hours/night. RESULTS: Because of dropout of 19 patients...... using the probably most relevant "worst case" data. There were no relevant difference between the effects of the water bed and the foam bed. CONCLUSION: The Waterbed and foam mattress' did influence back symptoms, function and sleep more positively as apposed to the hard mattress, but the differences...