Efficient particulate scrubber for glass melter off-gas

International Nuclear Information System (INIS)

Wright, G.T.

1983-01-01

Operation of joule-heated, continuous slurry-fed melters has demonstrated that off-gas aerosols are generated by entrainment of feed slurry and vaporization of volatile species from the melt. Effective off-gas stream decontamination for these aerosols can be obtained by utilizing a suitably designed and operated wet scrubber system. Results are presented for performance tests conducted with an air aspirating-type venturi scrubber processing a simulated melter off-gas aerosol. Mass overall removal efficiencies ranged from 99.5 to 99.8%. Details of the testing program and applications for melter off-gas system design are discussed

Design of off-gas and air cleaning systems at nuclear power plants

International Nuclear Information System (INIS)

1987-01-01

The primary purpose of this report is to describe the current design of air and process off-gas cleaning technologies used in nuclear power plants (NPPs). Because of the large inventory of fission products that are produced in the fuel (i.e. in the range of 5x10 19 Bq per GW(e)·a) and the highly restrictive airborne radionuclide release limits being established by Member States, air and process off-gas cleaning technologies are constantly being improved to provide higher airborne radionuclide recovery efficiencies and a smaller probability of malfunction. For various technologies considered an attempt has been made to provide the following information: (a) Process description in terms of principles of off-gas and air cleaning, operating parameters and system performance; (b) Design for normal and accident situations; (c) Design of components with regard to construction materials, size, shape and geometry of the system, resistance to chemical and physical degradation from the operational environment, safety and quality assurance requirements

Selective Trapping of Volatile Fission Products with an Off-Gas Treatment System

Energy Technology Data Exchange (ETDEWEB)

B.R. Westphal; J.J. Park; J.M. Shin; G.I. Park; K.J. Bateman; D.L. Wahlquist

2008-07-01

A head-end processing step, termed DEOX for its emphasis on decladding via oxidation, is being developed for the treatment of spent oxide fuel by pyroprocessing techniques. The head-end step employs high temperatures to oxidize UO2 to U3O8 resulting in the separation of fuel from cladding and the removal of volatile fission products. Development of the head-end step is being performed in collaboration with the Korean Atomic Energy Research Institute (KAERI) through an International Nuclear Energy Research Initiative. Following the initial experimentation for the removal of volatile fission products, an off-gas treatment system was designed in conjunction with KAERI to collect specific fission gases. The primary volatile species targeted for trapping were iodine, technetium, and cesium. Each species is intended to be collected in distinct zones of the off-gas system and within those zones, on individual filters. Separation of the volatile off-gases is achieved thermally as well as chemically given the composition of the filter media. A description of the filter media and a basis for its selection will be given along with the collection mechanisms and design considerations. In addition, results from testing with the off-gas treatment system will be presented.

ISOLDE Off-line Gas Leak Upgrade

CERN Document Server

Nielsen, Kristoffer Bested

2017-01-01

This study investigates gas injection system of the ISOLDE Off-line separator. A quadrupole mass spectrometer is used to analysis the composition of the gas. Based on these measurements a contamination of the injected gas is found and a system upgrade is purposed. Furthermore a calibration of the leak rate of the leak valve is made.

Microwave off-gas treatment apparatus and process

Science.gov (United States)

Schulz, Rebecca L.; Clark, David E.; Wicks, George G.

2003-01-01

The invention discloses a microwave off-gas system in which microwave energy is used to treat gaseous waste. A treatment chamber is used to remediate off-gases from an emission source by passing the off-gases through a susceptor matrix, the matrix being exposed to microwave radiation. The microwave radiation and elevated temperatures within the combustion chamber provide for significant reductions in the qualitative and quantitative emissions of the gas waste stream.

Concept of off-gas purification in reprocessing plants

International Nuclear Information System (INIS)

Henrich, E.; von Ammon, R.

1986-01-01

Concepts and individual processes for the off-gas purification in reprocessing plants are described which are suited to achieve a better retention of the gaseous and volatile radionuclides 129 I, 85 Kr, 14 C, and tritium. Improved and new process steps have been developed to the cold pilot plant scale. Essential individual process steps are an efficient iodine desorption from the dissolver solution, improved and new off-gas scrubs with nitric acid, a cryogenic as well as a selective absorption process for rare gas recovery plus the required prepurification steps and a process for the continuous and pressure-free fixation and storage of krypton in a metal matrix. Individual facilities have been selected and combined to investigate integrated dissolver off-gas systems. Advanced concepts based on a process using low flows and loads of all off-gas streams including the cell ventilation off-gas are briefly discussed

Studies in the dissolver off-gas system for a spent FBR fuel reprocessing plant

International Nuclear Information System (INIS)

Heinrich, E.; Huefner, R.; Weirich, F.

1982-01-01

Investigations of possible modifications of the process steps of a dissolver off-gas (DOG) system for a spent FBR fuel reprocessing plant are reported. The following operations are discussed: iodine removal from the fuel solution; behaviour of NOsub(x) and iodine in nitric acid off-gas scrubbers at different temperatures and nitric acid concentrations; iodine desorption from the scrub acid; selective absorption of noble gases in refrigerant-12; cold traps. The combination of suitable procedures to produce a total DOG system is described. (U.K.)

Recovery of krypton-85 from dissolver off-gas streams

International Nuclear Information System (INIS)

Law, J.P.; Lamb, K.M.

1988-01-01

The Rare Gas Plant at the Idaho Chemical Processing Plant Recovers fission product krypton and xenon from dissolver off gas streams. Recently the system was upgraded to allow processing of hydrogen rich dissolver off-gas streams. A trickle bed hydrogen recombiner was installed and tested. The Rare Gas Plant can now safely process gas streams containing up to 80% hydrogen

Removal of CO2 in closed loop off-gas treatment systems

International Nuclear Information System (INIS)

Clemens, M.K.; Nelson, P.A.; Swift, W.M.

1994-01-01

A closed loop test system has been installed at Argonne National Laboratory (ANL) to demonstrate off-gas treatment, absorption, and purification systems to be used for incineration and vitrification of hazardous and mixed waste. Closed loop systems can virtually eliminate the potential for release of hazardous or toxic materials to the atmosphere during both normal and upset conditions. In initial tests, a 250,000 Btu/h (75 kW thermal) combustor was operated in an open loop to produce a combustion product gas. The CO 2 in these tests was removed by reaction with a fluidized bed of time to produce CaCO 3 . Subsequently, recirculation system was installed to allow closed loop operation with the addition of oxygen to the recycle stream to support combustion. Commercially marketed technologies for removal of CO 2 can be adapted for use on closed loop incineration systems. The paper also describes the Absorbent Solution Treatment (AST) process, based on modifications to commercially demonstrated gas purification technologies. In this process, a side loop system is added to the main loop for removing CO 2 in scrubbing towers using aqueous-based CO 2 absorbents. The remaining gas is returned to the incinerator with oxygen addition. The absorbent is regenerated by driving off the CO 2 and water vapor, which are released to the atmosphere. Contaminants are either recycled for further treatment or form precipitates which are removed during the purification and regeneration process. There are no direct releases of gases or particulates to the environment. The CO 2 and water vapor go through two changes of state before release, effectively separating these combustion products from contaminants released during incineration. The AST process can accept a wide range of waste streams. The system may be retrofitted to existing Facilities or included in the designs for new installations

Advanced Off-Gas Control System Design For Radioactive And Mixed Waste Treatment

International Nuclear Information System (INIS)

Nick Soelberg

2005-01-01

Treatment of radioactive and mixed wastes is often required to destroy or immobilize hazardous constituents, reduce waste volume, and convert the waste to a form suitable for final disposal. These kinds of treatments usually evolve off-gas. Air emission regulations have become increasingly stringent in recent years. Mixed waste thermal treatment in the United States is now generally regulated under the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards. These standards impose unprecedented requirements for operation, monitoring and control, and emissions control. Off-gas control technologies and system designs that were satisfactorily proven in mixed waste operation prior to the implementation of new regulatory standards are in some cases no longer suitable in new mixed waste treatment system designs. Some mixed waste treatment facilities have been shut down rather than have excessively restrictive feed rate limits or facility upgrades to comply with the new standards. New mixed waste treatment facilities in the U. S. are being designed to operate in compliance with the HWC MACT standards. Activities have been underway for the past 10 years at the INL and elsewhere to identify, develop, demonstrate, and design technologies for enabling HWC MACT compliance for mixed waste treatment facilities. Some specific off-gas control technologies and system designs have been identified and tested to show that even the stringent HWC MACT standards can be met, while minimizing treatment facility size and cost

Cleanable sintered metal filters in hot off-gas systems

International Nuclear Information System (INIS)

Schurr, G.A.

1981-01-01

Filters with sintered metal elements, arranged as tube bundles with backflush air cleaning, are the equivalent of bag filters for high-temperature, harsh environments. They are virtually the only alternative for high-temperature off-gas systems where a renewable, highly efficient particle trap is required. Tests were conducted which show that the sintered metal elements installed in a filter system provide effective powder collection in high-temperature atmospheres over thousands of cleaning cycles. Such a sintered metal filter system is now installed on the experimental defense waste calciner at the Savannah River Laboratory. The experimental results included in this paper were used as the basis for its design

Technology of off-gas treatment for liquid-fed ceramic melters

Energy Technology Data Exchange (ETDEWEB)

Scott, P.A.; Goles, R.W.; Peters, R.D.

1985-05-01

The technology for treating off gas from liquid-fed ceramic melters (LFCMs) has been under development at the Pacific Northwest Laboratory since 1977. This report presents the off-gas technology as developed at PNL and by others to establish a benchmark of development and to identify technical issues. Tests conducted on simulated (nonradioactive) wastes have provided data that allow estimation of melter off-gas composition for a given waste. Mechanisms controlling volatilization of radionuclides and noxious gases are postulated, and correlations between melter operation and emissions are presented. This report is directed to those familiar with LFCM operation. Off-gas treatment systems always require primary quench scrubbers, aerosol scrubbers, and final particulate filters. Depending on the composition of the off gas, equipment for removal of ruthenium, iodine, tritium, and noxious gases may also be needed. Nitrogen oxides are the most common noxious gases requiring treatment, and can be controlled by aqueous absorption or catalytic conversion with ammonia. High efficiency particulate air (HEPA) filters should be used for final filtration. The design criteria needed for an off-gas system can be derived from emission regulations and composition of the melter feed. Conservative values for melter off-gas composition can be specified by statistical treatment of reported off-gas data. Statistical evaluation can also be used to predict the frequency and magnitude of normal surge events that occur in the melter. 44 refs., 28 figs., 17 tabs.

Dynamic performance of power generation systems for off-shore oil and gas platforms

DEFF Research Database (Denmark)

Pierobon, Leonardo; Breuhaus, Peter; Haglind, Fredrik

2014-01-01

%) arises on the prediction of the rotational speed of the high pressure shaft, while the largest deviation (average relative error ~20%) occurs in the evaluation of the pressure at the outlet of the low pressure turbine. As waste heat recovery units (e.g. organic Rankine cycles) are likely...... to be implemented in future off-shore platforms, the proposed model may serve in the design phase for a preliminary assessment of the dynamic response of the power generation system and to evaluate if requirements such as minimum and maximum frequency during transient operation and the recovery time are satisfied......On off-shore oil and gas platforms two or more gas turbines typically support the electrical demand on site by operating as a stand-alone (island) power system. As reliability and availability are major concerns during operation, the dynamic performance of the power generation system becomes...

Off-gas processing method in reprocessing plant

International Nuclear Information System (INIS)

Kobayashi, Yoshihiro; Seki, Eiji.

1990-01-01

Off-gases containing a radioactive Kr gas generated in a nuclear fuel reprocessing plant are at first sent to a Kr gas separator. Then, the radioactive Kr gas extracted there is introduced to a Kr gas fixing device. A pretreatment and a post-treatment are applied by using a non-radioactive clean inert gas except for the Kr gas as a purge gas. If the radioactive Kr gas is contained in the off-gases discharged from the Kr gas fixing device after applying the post-treatment, the off gases are returned to the Kr gas separator. Accordingly, in a case where the radioactive Kr gas is contained in the off-gases discharged from the Kr gas fixing device, it is not necessary to apply the fixing treatment to all of the off gases. In view of the above, increase of the amount of processing gases can be suppressed and the radioactive Kr gas can be fixed efficiently and economically. (I.N.)

High-level waste vitrification off-gas cleanup technology

International Nuclear Information System (INIS)

Hanson, M.S.

1980-01-01

This brief overview is intended to be a basis for discussion of needs and problems existing in the off-gas clean-up technology. A variety of types of waste form and processes are being developed in the United States and abroad. A description of many of the processes can be found in the Technical Alternative Documents (TAD). Concurrently, off-gas processing systems are being developed with most of the processes. An extensive review of methodology as well as decontamination factors can be found in the literature. Since it is generally agreed that the most advanced solidification process is vitrification, discussion here centers about the off-gas problems related to vitrification. With a number of waste soldification facilities around the world in operation, it can be shown that present technology can satisfy the present requirement for off-gas control. However, a number of areas within the technology base show potential for improvement. Fundamental as well as verification studies are needed to obtain the improvements

Statistical methods to monitor the West Valley off-gas system

International Nuclear Information System (INIS)

Eggett, D.L.

1990-01-01

This paper reports on the of-gas system for the ceramic melter operated at the West Valley Demonstration Project at West Valley, NY, monitored during melter operation. A one-at-a-time method of monitoring the parameters of the off-gas system is not statistically sound. Therefore, multivariate statistical methods appropriate for the monitoring of many correlated parameters will be used. Monitoring a large number of parameters increases the probability of a false out-of-control signal. If the parameters being monitored are statistically independent, the control limits can be easily adjusted to obtain the desired probability of a false out-of-control signal. The principal component (PC) scores have desirable statistical properties when the original variables are distributed as multivariate normals. Two statistics derived from the PC scores and used to form multivariate control charts are outlined and their distributional properties reviewed

R and D for an off-gas treatment system for a slagging pyrolysis radioactive waste incinerator. Final report for Phase I

International Nuclear Information System (INIS)

Christian, J.D.; Kirstein, B.E.; Pence, D.T.

1978-01-01

Preliminary evaluations were made of off-gas treatment needs for a slagging pyrolysis incinerator (SPI) of Andco--Torrax design for the treatment of radioactive waste at the INEL. Approximate decontamination factors (DFs) for particulates of 10 7 and for volatilized radionuclides of 10 3 will be required across the off-gas system. If lead is present in the waste at concentrations greater than 25-to-120 g/metric ton, volatilized lead will result in formation of substantial deposits in the off-gas system and regenerative towers. A review was made of radioactive incinerator development. Particulate and volatile component removal mechanisms and devices were reviewed. Three off-gas treatment systems were proposed for the SPI which will provide DFs for particulates of 10 8 . 9 figures, 7 tables

Cryogenic system for collecting noble gases from boiling water reactor off-gas

International Nuclear Information System (INIS)

Schmauch, G.E.

1973-01-01

In boiling water reactors, noncondensible gases are expelled from the main condenser. This off-gas stream is composed largely of radiolytic hydrogen and oxygen, air in-leakage, and traces of fission product krypton and xenon. In the Air Products' treatment system, the stoichiometric hydrogen and oxygen are reacted to form water in a catalytic recombiner. The design of the catalytic recombiner is an extension of industrial gas technology developed for purification of argon and helium. The off-gas after the recombiner is processed by cryogenic air-separation technology. The gas is compressed, passed into a reversing heat exchanger where water vapor and carbon dioxide are frozen out, further cooled, and expanded into a distillation column where refrigeration is provided by addition of liquid nitrogen. More than 99.99 percent of the krypton and essentially 100 percent of the xenon entering the column are accumulated in the column bottoms. Every three to six months, the noble-gas concentrate accumulated in the column bottom is removed as liquid, vaporized, diluted with steam, mixed with hydrogen in slight excess of oxygen content, and fed to a small recombiner where all the oxygen reacts to form water. The resulting gas stream, containing from 20 to 40 percent noble gases, is compressed into small storage cylinders for indefinite retention or for decay of all fission gases except krypton-85, followed by subsequent release under controlled conditions and favorable meteorology. This treatment system is based on proven technology that is practiced throughout the industrial gas industry. Only the presence of radioactive materials in the process stream and the application in a nuclear power plant environment are new. Adaptations to meet these new conditions can be made without sacrificing performance, reliability, or safety

Design and operational experience with the off-gas cleaning system of the Seibersdorf incinerator plant

International Nuclear Information System (INIS)

Patek, P.

1982-05-01

After a description of the design and the construction principles of the incinerator building, the furnace and its attached auxilary devices are explained. The incinerator is layed out for low level wastes. It has a vertical furnace, operates with discontinuous feeding for trashes with heat-values between 600 and 10000 kcal/kg waste. The maximum throughput ammounts 40 kg/h. The purification of the off-gas is guaranteed by a multistage filter system: 2 stages with ceramic candles, an electrostatic filter and a HEPA-filter system. The control of the off-gas cleaning is carried out by a stack instrumentation, consisting of an aerosol-, gas-, iodine- and tritium-monitor; the building is surveilled by doserate- and aerosolmonitors. Finally the experiences of the first year of operation and the main problems in running the plant are described. (Author) [de

Design and operational experience with the off-gas cleaning system of the Seibersdorf incinerator plant

International Nuclear Information System (INIS)

Patek, P.R.M.

1983-01-01

After a description of the design and the construction principles of the incinerator building, the furnace and its attached auxiliary devices are explained. The incinerator is layed out for low level wastes. It has a vertical furnace, operates with discontinuous feeding for trashes with heat-values between 600 and 10,000 kcal/kg waste. The maximum throughput amounts to 40 kg/h. The purification of the off-gas is guaranteed by a multistage filter system: 2 stages with ceramic candles, an electrostatic filter and a HEPA-filter system. The control of the off-gas cleaning is carried out by a stack instrumentation, consisting of an aerosol-, gas-, iodine- and tritium-monitor; the building is surveyed by doserate and aerosolmonitors. Finally the experiences of the first year of operation and the main problems in running the plant are described. (author)

Design, Fabrication, and Shakeout Testing of ATALANTE Dissolver Off-Gas Sorbent-Based Capture System

International Nuclear Information System (INIS)

Walker Jr, Joseph Franklin; Jubin, Robert Thomas; Jordan, Jacob A.; Bruffey, Stephanie H.

2015-01-01

A sorbent-based capture system designed for integration into the existing dissolver off-gas (DOG) treatment system at the ATelier Alpha et Laboratoires pour ANalyses, Transuraniens et Etudes de retraitement (ATALANTE) facility has been successfully designed and fabricated and has undergone shakeout testing. Discussions with personnel from the ATALANTE facility provided guidance that was used for the design. All components for this system were specified, procured, and received on site at Oak Ridge National Laboratory (ORNL). The system was then fabricated and tested at ORNL to verify operation. Shakeout testing resulted in a simplified system. This system should be easily installed into the existing facility and should be straightforward to operate during future experimental testing. All parts were selected to be compatible with ATALANTE power supplies, space requirements, and the existing DOG treatment system. Additionally, the system was demonstrated to meet all of four design requirements. These include (1) a dissolver off-gas flow rate of ?100 L/h (1.67 L/min), (2) an external temperature of ?50°C for all system components placed in the hot cell, (3) a sorbent bed temperature of ~150°C, and (4) a gas temperature of ~150°C upon entry into the sorbent bed. The system will be ready for shipment and installation in the existing DOG treatment system at ATALANTE in FY 2016.

Online gas composition estimation in solid oxide fuel cell systems with anode off-gas recycle configuration

Science.gov (United States)

Dolenc, B.; Vrečko, D.; Juričić, Ð.; Pohjoranta, A.; Pianese, C.

2017-03-01

Degradation and poisoning of solid oxide fuel cell (SOFC) stacks are continuously shortening the lifespan of SOFC systems. Poisoning mechanisms, such as carbon deposition, form a coating layer, hence rapidly decreasing the efficiency of the fuel cells. Gas composition of inlet gases is known to have great impact on the rate of coke formation. Therefore, monitoring of these variables can be of great benefit for overall management of SOFCs. Although measuring the gas composition of the gas stream is feasible, it is too costly for commercial applications. This paper proposes three distinct approaches for the design of gas composition estimators of an SOFC system in anode off-gas recycle configuration which are (i.) accurate, and (ii.) easy to implement on a programmable logic controller. Firstly, a classical approach is briefly revisited and problems related to implementation complexity are discussed. Secondly, the model is simplified and adapted for easy implementation. Further, an alternative data-driven approach for gas composition estimation is developed. Finally, a hybrid estimator employing experimental data and 1st-principles is proposed. Despite the structural simplicity of the estimators, the experimental validation shows a high precision for all of the approaches. Experimental validation is performed on a 10 kW SOFC system.

Off-gas considerations for a vitrification plant in the republic of Korea

International Nuclear Information System (INIS)

Chun, Ung Kyung; Park, Jong Kil; Yang, Kyung Hwa; Song, Myung Jae

1997-01-01

The Republic of Korea is in the process of preparing for its first ever vitrification plant to handle low and intermediate-level radioactive waste from her pressurized water reactors (PWRs). KEPRI, in coordination with her partners, will design, construct, and erect a pilot plant using data from the orientation tests. The pilot plant will be the basis for the development of the final objective, the establishment of an industrial scale vitrification installation in the Republic of Korea. Throughout these projects, the major goal is to minimize the harmful effects of the final waste form to the environment. The gaseous effluents emissions from the facility will need to be managed to meet the environmental regulations concerning gaseous releases into the environment of the Republic of Korea. The focus of this paper is on the considerations for the treatment of the off-gas for a low and intermediate-level radioactive waste treatment vitrification installation in the Republic of Korea. Off-gas considerations will span a wide-range of areas such as waste characteristics, thermal treatment systems, off-gas regulations, off-gas characteristics, assessment of air pollution control devices, systems assessments, numerical modelling, economics etc. Off-gas regulations in Korea are becoming tighter and will likely change from year to year. In terms of both off-gas treatment equipment performance and public protection, the amount and nature (e.g. chemical behavior and morphology) of the species are important. The emissions may be classified as toxic metals, radionuclides, hydrocarbons, particulate matter, and acid gases. Air pollution control technologies are generally classified as wet or dry technologies covering over 40 different air pollution control devices (APCDs) with varying removal efficiencies for the different types of off-gas. In general, the state of the art systems for vitrification technologies incorporate the basic functions such as further oxidation of products

Adsorption Model for Off-Gas Separation

Energy Technology Data Exchange (ETDEWEB)

Veronica J. Rutledge

2011-03-01

The absence of industrial scale nuclear fuel reprocessing in the U.S. has precluded the necessary driver for developing the advanced simulation capability now prevalent in so many other countries. Thus, it is essential to model complex series of unit operations to simulate, understand, and predict inherent transient behavior and feedback loops. A capability of accurately simulating the dynamic behavior of advanced fuel cycle separation processes will provide substantial cost savings and many technical benefits. The specific fuel cycle separation process discussed in this report is the off-gas treatment system. The off-gas separation consists of a series of scrubbers and adsorption beds to capture constituents of interest. Dynamic models are being developed to simulate each unit operation involved so each unit operation can be used as a stand-alone model and in series with multiple others. Currently, an adsorption model has been developed in gPROMS software. Inputs include gas stream constituents, sorbent, and column properties, equilibrium and kinetic data, and inlet conditions. It models dispersed plug flow in a packed bed under non-isothermal and non-isobaric conditions for a multiple component gas stream. The simulation outputs component concentrations along the column length as a function of time from which the breakthrough data is obtained. It also outputs temperature along the column length as a function of time and pressure drop along the column length. Experimental data will be input into the adsorption model to develop a model specific for iodine adsorption on silver mordenite as well as model(s) specific for krypton and xenon adsorption. The model will be validated with experimental breakthrough curves. Another future off-gas modeling goal is to develop a model for the unit operation absorption. The off-gas models will be made available via the server or web for evaluation by customers.

Protection and safety functions of different off-gas treatment systems in radioactive waste incineration

International Nuclear Information System (INIS)

Caramelle, D.; Chevalier, G.; Chevalier, G.

1986-01-01

Gaseous effluent cleaning installations are designed to protect workmen and environment and must be efficient enough to guarantee that the amounts of gases and dusts emitted by a furnace operating normally or accidentally are at an acceptable level in the atmosphere on the incinerator site. The process equipments necessary to operations and the monitoring devices must be reliable. The main risk in normal operation is occupational exposure close to the radioactive products accumulation points. The accidental risks are mainly related to an outage of the off-gas cleaning or a tightness failure with radioactive products dissemination resulting from either internal perturbation (filter tear, exhauster failure, ...) or external incident (electricity cut-off, furnace disarrangements, fire or explosion inside the incinerator). In view of these risks, it is interesting to examine the safety and protection functions of different components of off-gas treatment systems

Assessment of off-design performance of a small-scale combined cooling and power system using an alternative operating strategy for gas turbine

International Nuclear Information System (INIS)

Han, Wei; Chen, Qiang; Lin, Ru-mou; Jin, Hong-guang

2015-01-01

Highlights: • We develop an off-design model for a CCP system driven by gas turbine. • An alternative operating strategy is proposed to improve the system performance. • Off-design performance of the combined cooling and power system (CCP) is enhanced. • Effects of both the different operating strategy are analyzed and compared. • Performance enhancement mechanism of the proposed operating strategy is presented. - Abstract: A small-scale combined cooling and power (CCP) system usually serves district air conditioning apart from power generation purposes. The typical system consists of a gas turbine and an exhaust gas-fired absorption refrigerator. The surplus heat of the gas turbine is recovered to generate cooling energy. In this way, the CCP system has a high overall efficiency at the design point. However, the CCP system usually runs under off-design conditions because the users’ demand varies frequently. The operating strategy of the gas turbine will affect the thermodynamic performance of itself and the entire CCP system. The operating strategies for gas turbines include the reducing turbine inlet temperature (TIT) and the compressor inlet air throttling (IAT). A CCP system, consisting of an OPRA gas turbine and a double effects absorption refrigerator, is investigated to identify the effects of different operating strategies. The CCP system is simulated based on the partial-load model of gas turbine and absorption refrigerator. The off-design performance of the CCP system is compared under different operating strategies. The results show that the IAT strategy is the better one. At 50% rated power output of the gas turbine, the IAT operating strategy can increase overall system efficiency by 10% compared with the TIT strategy. In general, the IAT operating strategy is suited for other gas turbines. However, the benefits of IAT should be investigated in the future, when different gas turbine is adopted. This study may provide a new operating

Corrosion in the off-gas system of a radioactive-waste incinerator

International Nuclear Information System (INIS)

Jenkins, C.F.; Peters, J.J.

1987-01-01

Corrosion in a low-level radioactive-waste incinerator off-gas system at the Department of Energy's Savannah River Plant is discussed. Severe corrosive attack and failure of an alloy 600 part exposed to high-temperature (>1000 0 C) gases was observed. Rapid attack of carbon steel components, and cracking of austenitic stainless steel parts also occurred at locations where lower gas temperatures and periodic condensate exposure occurred. Investigation showed HCl, SO 2 , SO 3 and phosphorus-oxides were present and contributed to the failures. Mechanisms of high-temperature failure include alloy separation and reactions with phosphorus. Coupons placed in the exhaust stream have provided information for selection of future materials of construction for system components. Several nickel- and iron-base alloys, and a stainless steel with an aluminum-diffusion coating were investigated

Fabrication of remote steam atomized scrubbers for DWPF off-gas system

International Nuclear Information System (INIS)

Nielsen, M.G.; Lafferty, J.D.

1988-01-01

The defense waste processing facility (DWPF) is being constructed for the purpose of processing high-level waste from sludge to a vitrified borosilicate glass. In the operation of continuous slurry-fed melters, off-gas aerosols are created by entrainment of feed slurries and the vaporization of volatile species from the molten glass mixture. It is necessary to decontaminate these aerosols in order to minimize discharge of airborne radionuclide particulates. A steam atomized scrubber (SAS) has been developed for DWPF which utilizes a patented hydro- sonic system gas scrubbing method. The Hydro-Sonic System utilizes a steam aspirating-type venturi scrubber that requires very precise fabrication tolerances in order to obtain acceptable decontamination factors. In addition to the process-related tolerances, precision mounting and nozzle tolerances are required for remote service at DWPF

Simulation of gas turbines operating in off-design condition

Energy Technology Data Exchange (ETDEWEB)

Walter, Arnaldo [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Energia]. E-mail: walter@fem.unicamp.br

2000-07-01

In many countries thermal power plants based on gas turbines have been the main option for new investment into the electric system due to their relatively high efficiency and low capital cost. Cogeneration systems based on gas turbines have also been an important option for the electric industry. Feasibility studies of power plants based on gas turbine should consider the effect of atmospheric conditions and part-load operation on the machine performance. Doing this, an off-design procedure is required. A G T off-design simulation procedure is described in this paper. Ruston R M was used to validate the simulation procedure that, general sense, presents deviations lower than 2.5% in comparison to manufacturer's data. (author)

Formation of the ZnFe2O4 phase in an electric arc furnace off-gas treatment system

International Nuclear Information System (INIS)

Suetens, T.; Guo, M.; Van Acker, K.; Blanpain, B.

2015-01-01

Highlights: • EAF dust was characterized with particle size analysis, XRF, and EPMA. • Slag particles showed no sign of reaction with Zn vapor. • Fe 2 O 3 particles showed different degrees of reaction based on their size. • The thermodynamic stability of Zn vapor in EAF off-gas ducts was reevaluated. • In presence of Fe 2 O 3 , Zn vapor reacts to form ZnFe 2 O 4 and ZnO. - Abstract: To better understand the phenomena of ZnFe 2 O 4 spinel formation in electric arc furnace dust, the dust was characterized with particle size analysis, X-ray fluorescence (XRF), electron backscatter diffraction (EBSD), and electron probe micro-analysis (EPMA). Different ZnFe 2 O 4 formation reaction extents were observed for iron oxide particles with different particle sizes. ZnO particles were present as both individual particles and aggregated on the surface of larger particles. Also, the slag particles found in the off-gas were shown not to react with the zinc vapor. After confirming the presence of a ZnFe 2 O 4 formation reaction, the thermodynamic feasibility of in-process separation – a new electric arc furnace dust treatment technology – was reevaluated. The large air intake and the presence of iron oxide particles in the off-gas were included into the thermodynamic calculations. The formation of the stable ZnFe 2 O 4 spinel phase was shown to be thermodynamically favorable in current electric arc furnace off-gas ducts conditions even before reaching the post combustion chamber

Off-gas control project

International Nuclear Information System (INIS)

Torgerson, D.F.; Smith, I.M.

1978-06-01

A program to develop and study off-gas abatement techniques has recently been initiated at Whiteshell Nuclear Research Establishment (WNRE). This report provides information on the properties and expected behaviour of reprocessing plant off-gases, and outlines the experimental program to be undertaken. (author)

DWPF Melter Off-Gas Flammability Assessment for Sludge Batch 9

Energy Technology Data Exchange (ETDEWEB)

Choi, A. S. [Savannah River Site (SRS), Aiken, SC (United States)

2016-07-11

The slurry feed to the Defense Waste Processing Facility (DWPF) melter contains several organic carbon species that decompose in the cold cap and produce flammable gases that could accumulate in the off-gas system and create potential flammability hazard. To mitigate such a hazard, DWPF has implemented a strategy to impose the Technical Safety Requirement (TSR) limits on all key operating variables affecting off-gas flammability and operate the melter within those limits using both hardwired/software interlocks and administrative controls. The operating variables that are currently being controlled include; (1) total organic carbon (TOC), (2) air purges for combustion and dilution, (3) melter vapor space temperature, and (4) feed rate. The safety basis limits for these operating variables are determined using two computer models, 4-stage cold cap and Melter Off-Gas (MOG) dynamics models, under the baseline upset scenario - a surge in off-gas flow due to the inherent cold cap instabilities in the slurry-fed melter.

FY-2001 Accomplishments in Off-gas Treatment Technology Development

Energy Technology Data Exchange (ETDEWEB)

Marshall, Douglas William

2001-09-01

This report summarizes the efforts funded by the Tank Focus Area to investigate nitrogen oxide (NOx) destruction (a.k.a. deNOx) technologies and off-gas scrubber system designs. The primary deNOx technologies that were considered are staged combustion (a.k.a. NOx reburning), selective catalytic reduction, selective non-catalytic reduction, and steam reformation. After engineering studies and a team evaluation were completed, selective catalytic reduction and staged combustion were considered the most likely candidate technologies to be deployed in a sodium-bearing waste vitrification facility. The outcome of the team evaluation factored heavily in the establishing a baseline configuration for off-gas and secondary waste treatment systems.

Development of high performance catalyst for off-gas treatment system in BWR

International Nuclear Information System (INIS)

Kawasaki, Toru; Kawabe, Kenichi; Maeda, Kiyomitsu; Matsubara, Hirofumi; Aizawa, Motohiro; Iizuka, Hidehiro; Kumagai, Naoki

2011-01-01

A high performance catalyst for off-gas treatment system in boiling water reactor (BWR) has been developed. The hydrogen concentration in the outlets of off-gas recombiners increased at several BWR plants in Japan. These phenomena were caused by deactivation of catalysts for the recombiners, and we assumed two types of deactivation mechanisms. The first cause was an increase of the amount of boehmite in the catalyst support due to alternation of the manufacturing process. The other cause was catalysts being poisoned by cyclic siloxanes that were introduced from the silicone sealant used in the upstream of the off-gas recombiners. The catalysts were manufactured by Pt adhering on alumina support. The conventional catalyst (CAT-A) used the aqueous solution of the chloroplatinic acid for adhesion of Pt. A dechlorination process by autoclave was applied to prevent the equipment at the downstream of the recombiners from stress corrosion cracking, but this process caused the support material to transform into boehmite. The boehmite-rich catalysts were deactivated more easily by organic silicon than gamma alumina-rich catalysts. Therefore, the CAT-A was replaced at many Japanese BWR plants by the improved catalyst (CAT-B), and their support was transformed into more stable gamma alumina by heating at 500degC. However, the siloxanes keep being detected in the off-gas though the source of siloxane had been removed and there still remain possibilities to deactivate the catalysts. Therefore, we have been developing high performance catalyst (CAT-C) that has higher activity and durability against poisoning. We investigated the properties of CAT-C by performance tests and instrumental analyses. The dependency of thermal output of nuclear reactor, and durability against siloxane poisoning were investigated. We found that CAT-C showed higher performance and better properties than CAT-B did. Moreover, we have been developing a modeling method to evaluate the hydrogen recombination

The integrated melter off-gas treatment systems at the West Valley Demonstration Project

International Nuclear Information System (INIS)

Vance, R.F.

1991-12-01

The West Valley Demonstration project was established by an act of Congress in 1980 to solidify the high level radioactive liquid wastes produced from operation of the Western New York Nuclear Services Center from 1966 to 1972. The waste will be solidified as borosilicate glass. This report describes the functions, the controlling design criteria, and the resulting design of the melter off-gas treatment systems

Materials performance in off-gas systems containing iodine

International Nuclear Information System (INIS)

Beavers, J.A.; Berry, W.E.; Griess, J.C.

1981-11-01

During the reprocessing of spent reactor fuel elements, iodine is released to gas streams from which it is ultimately removed by conversion to nonvolatile iodic acid. Under some conditions iodine can produce severe corrosion in off-gas lines; in this study these conditions were established. Iron- and nickel-based alloys containing more than 6% molybdenum, such as Hastelloy G (7%), Inconel 625 (9%), and Hastelloy C-276 (16%), as well as titanium and zirconium, remained free of attack under all conditions tested. When the other materials, notably the austenitic stainless steels, were exposed to gas streams containing even only low concentrations of iodine and water vapors at 25 and 40 0 C, a highly corrosive, brownish-green liquid formed on their surfaces. In the complete absence of water vapor, the iodine-containing liquid did not form and all materials remained unaffected. The liquid that formed had a low pH (usually 2 inhibited attack

Enhancing energy recovery in the steel industry: Matching continuous charge with off-gas variability smoothing

International Nuclear Information System (INIS)

Dal Magro, Fabio; Meneghetti, Antonella; Nardin, Gioacchino; Savino, Stefano

2015-01-01

Highlights: • A system based on phase change material is inserted into the off-gas-line of a continuous charge electric arc furnace. • The off-gas temperature profile after scrap preheating is smoothed. • A heat transfer fluid through phase change material containers allows to control overheating issues. • The smoothed off-gas profiles enable efficient downstream power generation. • The recovery system investment cost is decreased due to lower sizes of components. - Abstract: In order to allow an efficient energy recovery from off-gas in the steel industry, the high variability of heat flow should be managed. A temperature smoothing device based on phase change materials at high temperatures is inserted into the off-gas line of a continuous charge electric arc furnace process with scrap preheating. To address overheating issues, a heat transfer fluid flowing through containers is introduced and selected by developing an analytical model. The performance of the smoothing system is analyzed by thermo-fluid dynamic simulations. The reduced maximum temperature of off-gas allows to reduce the size and investment cost of the downstream energy recovery system, while the increased minimum temperature enhances the steam turbine load factor, thus increasing its utilization. Benefits on environmental issues due to dioxins generation are also gained

Peer review panel summary report for technical determination of mixed waste incineration off-gas systems for Rocky Flats

International Nuclear Information System (INIS)

1992-01-01

A Peer Review Panel was convened on September 15-17, 1992 in Boulder, Co. The members of this panel included representatives from DOE, EPA, and DOE contractors along with invited experts in the fields of air pollution control and waste incineration. The primary purpose of this review panel was to make a technical determination of a hold, test and release off gas capture system should be implemented in the proposed RF Pland mixed waste incineration system; or if a state of the art continuous air pollution control and monitoring system should be utilized as the sole off-gas control system. All of the evaluations by the panel were based upon the use of the fluidized bed unit proposed by Rocky Flats and cannot be generalized to other systems

Stabilization of constrained uncertain systems by an off-line approach using zonotopes

Directory of Open Access Journals (Sweden)

Walid Hamdi

2018-01-01

Full Text Available In this paper, stabilization of uncertain systems was established using zonotopic sets. The obtained state feedback control laws are computed by an off-line approach reducing computational burdens. The resolution of a robust model predictive control (MPC allows computing a sequence of state feedback control laws corresponding to a sequence of zonotopic invariant sets. The implemented control laws are then calculated by linear interpolation between the state feedback gains corresponding to the nested pre-computed zonotopic sets. The proposed interpolation with the use of zonotopic sets achieves better control performances.

Design report: An off gas trapping system for a voloxidizer in INL of US

International Nuclear Information System (INIS)

Jung, I. H.; Shin, J. M.; Park, J. J.; Park, G. I.; Lee, H. H.

2006-09-01

This reports on the 'Development of Voloxidation Process for Treatment of LWR Spent Fuel', and it is the second year since it has started from June 2004 as a tripartite cooperation project among KAERI(Korea Atomic Energy Research Institute), INL(Idaho National Laboratory) and ORNL(Oak Ridge National Laboratory). This report is described mainly for the Task B2 accomplished during the second project year. The Task B2 in proposal contains two sub-tasks. The first one is design of an off-gas treatment system for a voloxidizer to be used in HFEF of INL. For this, KAERI team developed the design of INL OTS (Off-gas Treatment System) for hot experiment in the HFEF. INL team modified and completed the design of the INL OTS. The second task is manufacturing and test operation of the INL OTS for a voloxidizer in the INL. Manufacturing of the OTS is accomplished by INL team with co-work of KAERI. KAERI provided four sets of trapping filters needed for conducting hot experiment in the INL HFEF

Modular design of a reprocessing plant dissolver off-gas system. Variations, flexibility and stage of development

International Nuclear Information System (INIS)

Henrich, E.; Huefner, R.

1984-01-01

Simple and economic control of the volatile radionuclides in a reprocessing plant requires two equally important prerequisites: suitable processing in the plant head-end and reliable operation of the dissolver off-gas (DOG) purification system. A small number of DOG purification modules was selected from various alternatives. The major selection criteria are removal efficiency, simplicity, convenient operating conditions and flexibility that provide compatibility with other off-gas treatment steps, subsequent waste treatment and different processing modes in the head-end. The behaviour of noxious materials was investigated in nitric acid off-gas scrubbers of different design and for a wide range of operating modes and conditions. A concentration range of nitric acid from very dilute to hyperazeotropic concentrations and a temperature range from -55 deg. C to above room temperature as well as the use of hydrogen peroxide were studied on an engineering scale. Nitrous gases and iodine can be removed to the trace level at special operating modes. Aerosol and iodine filters are discussed briefly. A selective absorption process using CF 2 Cl 2 solvent for noble gas and 14 C removal was developed on a laboratory scale. It operates at low temperatures and atmospheric pressure. Xe and Kr were separated using two absorption columns. Pilot-plant scale noble gas scrubbers are under construction and are being integrated into the existing test facility. A series of process steps has been chosen for integrated process demonstration runs on an engineering scale. The integrated DOG system consists of several scrubbers and filters operating at atmospheric pressure. The temperature decreases stepwise, without producing large changes in the opposite direction, providing compatibility within the process train

Literature review: Assessment of DWPF melter and melter off-gas system lifetime

Energy Technology Data Exchange (ETDEWEB)

Reigel, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-07-30

A glass melter for use in processing radioactive waste is a challenging environment for the materials of construction (MOC) resulting from a combination of high temperatures, chemical attack, and erosion/corrosion; therefore, highly engineered materials must be selected for this application. The focus of this report is to review the testing and evaluations used in the selection of the Defense Waste Processing Facility (DWPF), glass contact MOC specifically the Monofrax® K-3 refractory and Inconel® 690 alloy. The degradation or corrosion mechanisms of these materials during pilot scale testing and in-service operation were analyzed over a range of oxidizing and reducing flowsheets; however, DWPF has primarily processed a reducing flowsheet (i.e., Fe²⁺/ΣFe of 0.09 to 0.33) since the start of radioactive operations. This report also discusses the materials selection for the DWPF off-gas system and the corrosion evaluation of these materials during pilot scale testing and non-radioactive operations of DWPF Melter #1. Inspection of the off-gas components has not been performed during radioactive operations with the exception of maintenance because of plugging.

Literature review: Assessment of DWPF melter and melter off-gas system lifetime

Energy Technology Data Exchange (ETDEWEB)

Reigel, M. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-07-30

A glass melter for use in processing radioactive waste is a challenging environment for the materials of construction (MOC) resulting from a combination of high temperatures, chemical attack, and erosion/corrosion; therefore, highly engineered materials must be selected for this application. The focus of this report is to review the testing and evaluations used in the selection of the Defense Waste Processing Facility (DWPF), glass contact MOC specifically the Monofrax^® K-3 refractory and Inconel^® 690 alloy. The degradation or corrosion mechanisms of these materials during pilot scale testing and in-service operation were analyzed over a range of oxidizing and reducing flowsheets; however, DWPF has primarily processed a reducing flowsheet (i.e., Fe²⁺/ΣFe of 0.09 to 0.33) since the start of radioactive operations. This report also discusses the materials selection for the DWPF off-gas system and the corrosion evaluation of these materials during pilot scale testing and non-radioactive operations of DWPF Melter #1. Inspection of the off-gas components has not been performed during radioactive operations with the exception of maintenance because of plugging.

Mathematical modelling of heat transfer in dedusting plants and comparison to off-gas measurements at electric arc furnaces

International Nuclear Information System (INIS)

Kirschen, Marcus; Velikorodov, Viktor; Pfeifer, Herbert

2006-01-01

A mathematical simulation tool is presented in order to model enthalpy flow rates of off-gas and heat transfer of cooling systems at dedusting plants in electric steel making sites. The flexibility of the simulation tool is based on a user-defined series of modular units that describe elementary units of industrial dedusting systems, e.g. water-cooled hot gas duct, air injector, drop-out box, mixing chamber, post-combustion chamber, filter, etc. Results of simulation were checked with measurements at industrial electric steel making plants in order to validate the models for turbulence, heat transfer and chemical reaction kinetics. Comparison between computed and measured gas temperature and composition yield excellent agreement. The simulation tool is used to calculate off-gas temperature and volume flow rate, where off-gas measurements are very difficult to apply due to high gas temperatures and high dust load. Heat transfer from the off-gas to the cooling system was calculated in detail for a pressurised hot water EAF cooling system in order to investigate the impact of the cooling system and the dedusting plant operation on the energy sinks of the electric arc furnace. It is shown that optimum efficiency of post-combustion of EAF off-gas in the water-cooled hot gas duct requires continuous off-gas analysis. Common operation parameters of EAF dedusting systems do not consider the non-steady-state of the EAF off-gas emission efficiently

Mathematical modelling of heat transfer in dedusting plants and comparison to off-gas measurements at electric arc furnaces

Energy Technology Data Exchange (ETDEWEB)

Kirschen, Marcus [Institute for Industrial Furnaces and Heat Engineering, RWTH Aachen, Kopernikusstrasse 16, 52074 Aachen (Germany)]. E-mail: kirschen@iob.rwth-aachen.de; Velikorodov, Viktor [Institute for Industrial Furnaces and Heat Engineering, RWTH Aachen, Kopernikusstrasse 16, 52074 Aachen (Germany); Pfeifer, Herbert [Institute for Industrial Furnaces and Heat Engineering, RWTH Aachen, Kopernikusstrasse 16, 52074 Aachen (Germany)

2006-11-15

A mathematical simulation tool is presented in order to model enthalpy flow rates of off-gas and heat transfer of cooling systems at dedusting plants in electric steel making sites. The flexibility of the simulation tool is based on a user-defined series of modular units that describe elementary units of industrial dedusting systems, e.g. water-cooled hot gas duct, air injector, drop-out box, mixing chamber, post-combustion chamber, filter, etc. Results of simulation were checked with measurements at industrial electric steel making plants in order to validate the models for turbulence, heat transfer and chemical reaction kinetics. Comparison between computed and measured gas temperature and composition yield excellent agreement. The simulation tool is used to calculate off-gas temperature and volume flow rate, where off-gas measurements are very difficult to apply due to high gas temperatures and high dust load. Heat transfer from the off-gas to the cooling system was calculated in detail for a pressurised hot water EAF cooling system in order to investigate the impact of the cooling system and the dedusting plant operation on the energy sinks of the electric arc furnace. It is shown that optimum efficiency of post-combustion of EAF off-gas in the water-cooled hot gas duct requires continuous off-gas analysis. Common operation parameters of EAF dedusting systems do not consider the non-steady-state of the EAF off-gas emission efficiently.

Technology survey for real-time monitoring of plutonium in a vitrifier off-gas system

International Nuclear Information System (INIS)

Berg, J.M.; Veirs, D.K.

1996-01-01

We surveyed several promising measurement technologies for the real-time monitoring of plutonium in a vitrifier off-gas system. The vitrifier is being developed by Westinghouse Savannah River Corp. and will be used to demonstrate vitrification of plutonium dissolved in nitric acid for fissile material disposition. The risk of developing a criticality hazard in the off-gas processing equipment can be managed by using available measurement technologies. We identified several potential technologies and methods for detecting plutonium that are sensitive enough to detect the accumulation of a mass sufficient to form a criticality hazard. We recommend gross alpha-monitoring technologies as the most promising option for Westinghouse Savannah River Corp. to consider because that option appears to require the least additional development. We also recommend further consideration for several other technologies because they offer specific advantages and because gross alpha-monitoring could prove unsuitable when tested for this specific application

Iodine Adsorption by Ag-Aerogel under Prototypical Vessel Off-Gas Conditions

Energy Technology Data Exchange (ETDEWEB)

Bruffey, Stephanie H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jubin, Robert Thomas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2016-08-01

U.S. regulations will require the removal of ¹²⁹I from the off-gas streams of any used nuclear fuel (UNF) reprocessing plant prior to discharge of the off-gas to the environment. The required plant decontamination factor for iodine will vary based on fuel burnup, cooling time, and other factors but is very likely to be >1000 and could be as high as 8000. Multiple off-gas streams within a UNF reprocessing plant combine prior to environmental release, and each of these streams contains some amount of iodine. To achieve the decontamination factors (DFs) that are likely to be required by regulations, iodine removal from the vessel off-gas will be necessary. The vessel off-gas contains iodine at very dilute concentrations (ppb levels), and will also contain water vapor. Iodine species present are likely to include both elemental and organic iodides. There will also be solvent vapors and volatile radiolysis products. The United States has considered the use of silver-based sorbents for removal of iodine from UNF off-gas streams, but little is known about the behavior of those sorbents at very dilute iodine concentrations. The purpose of this study was to expose silver-functionalized silica aerogel (AgAerogel) to a prototypical vessel off-gas stream containing 40 ppb methyl iodide to obtain information about organic iodine capture by silver-sorbents at very low iodine concentrations. The design of this extended duration testing was such that information about the rate of adsorption, the penetration of the iodine species, and the overall system DF could be obtained. Results show that CH₃I penetrates into a AgAerogel sorbent bed to a depth of 3.9 cm under prototypical vessel off-gas conditions. An iodine loading of 22 mg I/g AgAerogel was observed in the first 0.3 cm of the bed. Of the iodine delivered to the system, 48% could not be accounted for, and future efforts will investigate this concern. Direct calculation of the decontamination factor is not

In-place testing of off-gas iodine filters

International Nuclear Information System (INIS)

Duce, S.W.; Tkachyk, J.W.; Motes, B.G.

1980-01-01

At the Idaho National Engineering Laboratory, both charcoal and silver zeolite (AgX) filters are used for radioactive iodine off-gas cleanup of reactor systems. These filters are used in facilities which are conducting research in the areas of reactor fuel failure, reactor fuel inspection, and loss of fluids from reactor vessels. Iodine retention efficiency testing of these filters is dictated by prudent safety practices and regulatory guidelines. A procedure for determining iodine off-gas filter efficiency in-place has been developed and tested on both AgX and charcoal filters. The procedure involves establishing sample points upstream and downstream of the filter to be tested. A step-by-step approach for filter efficiency testing is presented

Biological off-gas treatment: let's make things better

NARCIS (Netherlands)

Groenestijn, J.W. van

1998-01-01

Biological off-gas treatment is the most effective cleaning method for many off-gases which contain low concentration of pollutants (<5 g/m3). The world market share in off-gas treatment is a few percent. Potential buyers are reserved because of existing biofilter quality differences and lack of

Gas transfer system

International Nuclear Information System (INIS)

Oberlin, J.C.; Frick, G.; Kempfer, C.; North, C.

1988-09-01

The state of work on the Vivitron gas transfer system and the system functions are summarized. The system has to: evacuate the Vivitron reservoir; transfer gas from storage tanks to the Vivitron; recirculate gas during operation; transfer gas from the Vivitron to storage tanks; and assure air input. The system is now being installed. Leak alarms are given by SF6 detectors, which set off a system of forced ventilation. Another system continuously monitors the amount of SF6 in the tanks [fr

An appraisal of the enzyme stability-activity trade-off.

Science.gov (United States)

Miller, Scott R

2017-07-01

A longstanding idea in evolutionary physiology is that an enzyme cannot jointly optimize performance at both high and low temperatures due to a trade-off between stability and activity. Although a stability-activity trade-off has been observed for well-characterized examples, such a trade-off is not imposed by any physical chemical constraint. To better understand the pervasiveness of this trade-off, I investigated the stability-activity relationship for comparative biochemical studies of purified orthologous enzymes identified by a literature search. The nature of this relationship varied greatly among studies. Notably, studies of enzymes with low mean synonymous nucleotide sequence divergence were less likely to exhibit the predicted negative correlation between stability and activity. Similarly, a survey of directed evolution investigations of the stability-activity relationship indicated that these traits are often uncoupled among nearly identical yet phenotypically divergent enzymes. This suggests that the presumptive trade-off often reported for investigations of enzymes with high mean sequence divergence may in some cases instead be a consequence of the degeneration over time of enzyme function in unselected environments, rather than a direct effect of thermal adaptation. The results caution against the general assertion of a stability-activity trade-off during enzyme adaptation. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Formation of the ZnFe{sub 2}O{sub 4} phase in an electric arc furnace off-gas treatment system

Energy Technology Data Exchange (ETDEWEB)

Suetens, T., E-mail: thomas.suetens@mtm.kuleuven.be; Guo, M., E-mail: muxing.guo@mtm.kuleuven.be; Van Acker, K., E-mail: karel.vanacker@lrd.kuleuven.be; Blanpain, B., E-mail: bart.blanpain@mtm.kuleuven.be

2015-04-28

Highlights: • EAF dust was characterized with particle size analysis, XRF, and EPMA. • Slag particles showed no sign of reaction with Zn vapor. • Fe{sub 2}O{sub 3} particles showed different degrees of reaction based on their size. • The thermodynamic stability of Zn vapor in EAF off-gas ducts was reevaluated. • In presence of Fe{sub 2}O{sub 3}, Zn vapor reacts to form ZnFe{sub 2}O{sub 4} and ZnO. - Abstract: To better understand the phenomena of ZnFe{sub 2}O{sub 4} spinel formation in electric arc furnace dust, the dust was characterized with particle size analysis, X-ray fluorescence (XRF), electron backscatter diffraction (EBSD), and electron probe micro-analysis (EPMA). Different ZnFe{sub 2}O{sub 4} formation reaction extents were observed for iron oxide particles with different particle sizes. ZnO particles were present as both individual particles and aggregated on the surface of larger particles. Also, the slag particles found in the off-gas were shown not to react with the zinc vapor. After confirming the presence of a ZnFe{sub 2}O{sub 4} formation reaction, the thermodynamic feasibility of in-process separation – a new electric arc furnace dust treatment technology – was reevaluated. The large air intake and the presence of iron oxide particles in the off-gas were included into the thermodynamic calculations. The formation of the stable ZnFe{sub 2}O{sub 4} spinel phase was shown to be thermodynamically favorable in current electric arc furnace off-gas ducts conditions even before reaching the post combustion chamber.

LFCM [liquid-fed eramic melter] emission and off-gas system performance for feed component cesium

International Nuclear Information System (INIS)

Goles, R.W.; Andersen, C.M.

1986-09-01

Except for volatile off-gas effluents, overall adequacy of the liquid-fed ceramic melter (LFCM) system depends most upon its effectiveness in dealing with cesium. However, the mechanism responsible for melter cesium losses has proved insensitive to many LFCM operating and processing conditions. As a result, variations in inleakage, plenum temperature, feeding rate and waste loading do not significantly influence melter cesium performance. Feed composition, specifically halogen content, is the only processing variable that has had a significant effect. Due to the submicron nature of LFCM-generated aerosols, melter disengagement design features are not expected to be particularly effective in reducing cesium emission rates. For the same reason, the cesium performance of conventional quench scrubbers is quite low, being dependent only upon the magnitude of melter entrainment losses. Although a deep bed washable filter has been effective in removing submicron aerosols from the process exhaust, high performance has only been achieved under dry operating conditions. The melter's idling state does not appear to place additional demands upon the off-gas treatment system

Off-gas treatment and characterization for a radioactive in situ vitrification test

International Nuclear Information System (INIS)

Oma, K.H.; Timmerman, C.L.

1985-01-01

Effluents released to the off gas during the in situ vitrification (ISV) of a test site have been characterized. The site consisted of a 19 L waste package of soil containing 600 nCi/g transuranic and 30,000 nCi/g mixed fission products surrounded by uncontaminated soil. Radioactive isotopes present in the package were 241 Am, /sup 238/239/Pu, 137 Cs, 106 Ru, 90 Sr, and 60 Co. The ISV process melted the waste package and surrounding soil and immobilized the radionuclides in place, producing a durable, 8.6 metric ton glass and crystalline monolith. The test successfully demonstrated that the process provides containment of radioactive material. No release to the environment was detected during processing or cooldown. Due to the high temperatures during processing, some gases were released into the off-gas hood that was placed over the test site. The hood was maintained at a light negative pressure to contain any volatile or entrained material during processing. Gases passed from the hood to an off-gas treatment system where they were treated using a venturi-ejector scrubber, a tandem nozzle gas cleaner scrubber followed by a condenser, heater, and two stages of HEPA filters. The off-gas treatment system is located in the semi-trailer to allow transport of the process to other potential test sites. Retention of all radionuclides by the vitrified zone was greater than 99%. Soil-to-off-gas decontamination factors (DFs) for transuranic elements averaged greater than 4000 and for fission products, DFs ranged from 130 for 137 Cs to 3100 for 90 Sr

Off-gas adsorption model and simulation - OSPREY

Energy Technology Data Exchange (ETDEWEB)

Rutledge, V.J. [Idaho National Laboratory, P. O. Box 1625, Idaho Falls, ID (United States)

2013-07-01

A capability of accurately simulating the dynamic behavior of advanced fuel cycle separation processes is expected to provide substantial cost savings and many technical benefits. To support this capability, a modeling effort focused on the off-gas treatment system of a used nuclear fuel recycling facility is in progress. The off-gas separation consists of a series of scrubbers and adsorption beds to capture constituents of interest. Dynamic models are being developed to simulate each unit operation involved so each unit operation can be used as a stand-alone model and in series with multiple others. Currently, an adsorption model has been developed within Multi-physics Object Oriented Simulation Environment (MOOSE) developed at the Idaho National Laboratory (INL). Off-gas Separation and Recovery (OSPREY) models the adsorption of offgas constituents for dispersed plug flow in a packed bed under non-isothermal and non-isobaric conditions. Inputs to the model include gas composition, sorbent and column properties, equilibrium and kinetic data, and inlet conditions. The simulation outputs component concentrations along the column length as a function of time from which breakthrough data can be obtained. The breakthrough data can be used to determine bed capacity, which in turn can be used to size columns. In addition to concentration data, the model predicts temperature along the column length as a function of time and pressure drop along the column length. A description of the OSPREY model, results from krypton adsorption modeling and plans for modeling the behavior of iodine, xenon, and tritium will be discussed. (author)

Canadian development program for off-gas management in nuclear facilities

International Nuclear Information System (INIS)

Sridhar, T.S.

1983-01-01

The Canadian program for the development and evaluation of processes and technology for the separation and containment of radioactive species in off-gases is directed towards the following specific aspects: 1) assessment of available treatment technology and evaluation of future clean-up requirements; 2) development and engineering evaluation, under realistic conditions, of promising new processes that would be inherently simpler and safer; and 3) specification of off-gas emission control systems for future nuclear facilities based on the most favourable technology. The program is being carried out by Atomic Energy of Canada Limited in collaboration with the electrical utility, Ontario Hydro, and selected Canadian universities. A brief description is presented of methods for removing tritium and carbon-14 from the moderator systems of CANDU power reactors, methods for removing iodine from the off-gases of a molybdenum-99 production facility at the Chalk River Nuclear Laboratories, and procedures for monitoring the off-gas effluent composition in the Thorium Fuel Reprocessing Experiment (TFRE) facility at the Whiteshell Nuclear Research Establishment

Enhancement of energy performance in a boil-off gas re-liquefaction system of LNG carriers using ejectors

International Nuclear Information System (INIS)

Tan, Hongbo; Zhao, Qingxuan; Sun, Nannan; Li, Yanzhong

2016-01-01

Highlights: • An ejector-enhanced LNG boil-off gas (BOG) re-liquefaction system is proposed. • The new system has an improvement of 28% in COP over the existing system. • The specific energy consumption of the new system is reduced to 0.59 kW h/kg(BOG). • The power consumption of 754.1 kW is saved in the case study. - Abstract: An ejector-enhanced Liquefied Natural Gas (LNG) boil-off gas (BOG) re-liquefaction system is proposed to improve the energy efficiency of the existing system. In the new system, two ejectors are respectively used to reduce the energy loss in the expansion of the pressurized BOG and inject a part of fuel BOG into the compression system, and a recuperator is employed to recover the cold energy of the BOG exited from LNG tank. The performance improvement of the proposed system is analysed on the basis of the simulation in Aspen HYSYS. In the case of the re-liquefaction capacity of 4557.6 kg/h, the coefficient of performance (COP) and exergy efficiency can be increased by 28%, and the specific energy consumption (SEC) reduced from 0.756 to 0.59 kW h/kg(BOG) compared to the conventional BOG re-liquefaction system. Correspondingly, the power consumption of 754.1 kW is saved. This means that applying ejectors can effectively improve the energy efficiency of the existing BOG re-liquefaction system for LNG carriers.

The development and design of the off-gas treatment system for the thermal oxide reprocessing plant (THORP) at Sellafield

International Nuclear Information System (INIS)

Hudson, P.I.; Buckley, C.P.; Miller, W.W.

1995-01-01

British Nuclear Fuels completed construction of its Thermal Oxide Reprocessing Plant (THORP) at Sellafield in 1992, at a cost of 1,850M. After Government and Regulatory approval, active commissioning was initiated on 17 January 1994. From the outset, the need to protect the workforce, the public and the environment in general from the plant's discharges was clearly recognised. The design intent was to limit radiation exposure of members of the general public to As Low as Reasonably Practicable. Furthermore no member of the most highly exposed group should receive an annual dose exceeding 50 microsieverts from either the aerial or marine discharge routes. This paper describes how the design intent has been met with respect to aerial discharges. It outlines the development programme which was undertaken to address the more demanding aspects of the performance specification. This ranged from small-scale experiments with irradiated fuel to inactive pilot plant trials and full-scale plant measurements. The resulting information was then used, with the aid of mathematical models, in the design of an off-gas treatment system which could achieve the overall goal. The principal species requiring treatment in the THORP off-gas system are iodine-129, carbon-14, nitrogen oxides (NOx), fuel dust particles and aerosols containing plutonium or mixed fission products. The paper describes the combination of abatement equipment used in different parts of the plant, including counter-current absorption columns, electrostatic precipitators, dehumidifiers and High Efficiency Particulate Air filters. Because a number of separate off-gas streams are combined before discharge, special depression control systems were developed which have already proved successful during plant commissioning. BNFL is confident that the detailed attention given to the development and design phases of the THORP off-gas system will ensure good performance when the plant moves into fully radioactive operation

The development and design of the off-gas treatment system for the thermal oxide reprocessing plant (THORP) at Sellafield

Energy Technology Data Exchange (ETDEWEB)

Hudson, P.I. [British Nuclear Fuels, Sellafield (United Kingdom); Buckley, C.P.; Miller, W.W. [British Nuclear Fuels, Risley (United Kingdom)

1995-02-01

British Nuclear Fuels completed construction of its Thermal Oxide Reprocessing Plant (THORP) at Sellafield in 1992, at a cost of 1,850M. After Government and Regulatory approval, active commissioning was initiated on 17 January 1994. From the outset, the need to protect the workforce, the public and the environment in general from the plant`s discharges was clearly recognised. The design intent was to limit radiation exposure of members of the general public to As Low as Reasonably Practicable. Furthermore no member of the most highly exposed group should receive an annual dose exceeding 50 microsieverts from either the aerial or marine discharge routes. This paper describes how the design intent has been met with respect to aerial discharges. It outlines the development programme which was undertaken to address the more demanding aspects of the performance specification. This ranged from small-scale experiments with irradiated fuel to inactive pilot plant trials and full-scale plant measurements. The resulting information was then used, with the aid of mathematical models, in the design of an off-gas treatment system which could achieve the overall goal. The principal species requiring treatment in the THORP off-gas system are iodine-129, carbon-14, nitrogen oxides (NOx), fuel dust particles and aerosols containing plutonium or mixed fission products. The paper describes the combination of abatement equipment used in different parts of the plant, including counter-current absorption columns, electrostatic precipitators, dehumidifiers and High Efficiency Particulate Air filters. Because a number of separate off-gas streams are combined before discharge, special depression control systems were developed which have already proved successful during plant commissioning. BNFL is confident that the detailed attention given to the development and design phases of the THORP off-gas system will ensure good performance when the plant moves into fully radioactive operation.

Off-gas treatment and characterization for a radioactive in situ vitrification test

International Nuclear Information System (INIS)

Oma, K.H.; Timmerman, C.L.

1984-08-01

Effluents released to the off gas during the in situ vitrification (ISV) of a test site have been characterized by Pacific Northwest Laboratory. The site consisted of a 19 L waste package of soil containing 600 nCi/g transuranic and 30,000 nCi/g mixed fission products surrounded by uncontaminated soil. Radioactive isotopes present in the package were 241 Am, 238 / 239 Pu, 137 Cs, 106 Ru, 90 Sr, and 60 Co. The ISV process melted the waste package and surrounding soil and immobilized the radionuclides in place, producing a durable, 8.6 metric ton glass and crystalline monolith. The test successfully demonstrated that the process provides containment of radioactive material. No release to the environment was detected during processing of cooldown. Due to the high temperature during processing, some gases were released into the off-gas hood that was over the test site. The hood was maintained at a slight negative pressure to contain any volatile or entrained material during processing. Gases passed from the hood to an off-gas treatment system where they were treated using a venturi-ejector scrubber, a tandem nozzle gas cleaner scrubber followed by a condenser, heater, and two stages of HEPA filters. The off-gas treatment system is located in the semi-trailer to allow transport of the process to other potential test sites. Retention of all radionuclides by the vitrified zone was greater than 99%. Soil-to-off-gas decontamination factors (DFs) for transuranic elements averaged greater than 4000 and for fission products, DFs ranged from 130 for 137 Cs to 3100 for 90 Sr. 7 references, 15 figures, 4 tables

Financing gas plants using off balance sheet structures

International Nuclear Information System (INIS)

Best, R.J.; Malcolm, V.

1999-01-01

A means by which to finance oil and gas facilities using off balance sheet structures was presented. Off balance sheet facility financing means the sale by an oil and gas producer of a processing and/or transportation facility to a financial intermediary, who under a Management Agreement, appoints the producer as the operator of the facility. The financial intermediary charges a fixed processing fee to the producer and all the benefits and upside of ownership are retained by the producer. This paper deals specifically with a flexible off balance sheet facility financing structure that can be used to make effective use of discretionary capital which is committed to gas processing and to the construction of new gas processing facilities. Off balance sheet financing is an attractive alternative method of ownership that frees up capital that is locked into the facilities while allowing the producer to retain strategic control of the processing facility

Dissolution off-gases at the marcoule pilot facility: Iodine trapping and off-gas characterization unit

International Nuclear Information System (INIS)

Pouyat, D.; Vignau, B.; Roux, J.P.

1993-01-01

The Marcoule Pilot Reprocessing Facility (APM) reprocesses spent fuel from light water reactors and fast breeder reactors. A batch dissolution process is used with an annual throughput capacity of 5 metric tons. The off-gas treatment unit is described together with its characterization laboratory in order to highlight the functions and potential of the facilities. The objectives are consistent with the Marcoule site policy regarding diminished iodine release and investigation of the off-gas treatment process. The equipment used to meet these objectives is described from a functional standpoint. The facility implements measurement techniques to allow continuous quantitative measurements of nitrogen oxides, oxygen, iodine and krypton, as well as continuous monitoring of the demister inlet flow by γ spectrometry. Sorbents used for iodine trapping may be tested over a wide range of operating conditions (temperature, flow rate, iodine concentration) with representative dissolution off-gases. An X-ray and γ counting system is used to assess the activity of the adsorbed radionuclides, notably 129 I

Test results from the GA technologies engineering-scale off-gas treatment system

International Nuclear Information System (INIS)

Jensen, D.D.; Olguin, L.J.; Wilbourn, R.G.

1984-06-01

One method for reducing the volume of HTGR fuel prior to reprocessing or spent fuel storage is to crush and burn the graphite fuel elements. The burner off-gas (BOG) contains radioactive components, principally H-3, C-14, Kr-85, I-129, and Rn-220, as well as chemical forms such as CO 2 , CO, O 2 , and SO 2 . The BOG system employs components designed to remove these constitutents. Test results are reported for the iodine and SO 2 adsorbers and the CO/HT oxidizer. Silver-based iodine adsorbents were found to catalyze the premature conversion of CO to CO 2 . Subsequent tests showed that iodine removal could not be performed downstream of the CO/HT oxidizer since iodine in the BOG system rapidly deactivated the Pt-coated alumina CO catalyst. Lead-exchanged zeolite (PbX) was found to be an acceptable alternative for removing iodine from BOG without CO conversion. Intermittent and steady-state tests of the pilot-plant SO 2 removal unit containing sodium-exchanged zeolite (NaX) demonstrated that decontamination factors greater than or equal to 100 could be maintained for up to 50 h. In a reprocessing flowsheet, the solid product from the burners is dissolved in nitric or Thorex acid. The dissolver off-gas (DOG) contains radioactive components H-3, Kr-85, I-129, Rn-220 plus chemical forms such as nitrogen oxides (NO/sub x/). In the pilot-scale system at GA, iodine is removed from the DOG by adsorption. Tests of iodine removal have been conducted using either silver-exchanged mordenite (AgZ) or AgNO 3 -impregnated silica gel (AC-6120). Although each sorbent performed well in the presence of NO/sub x/, the silica gel adsorbent proved more efficient in silver utilization and, thus, more cost effective

FINAL REPORT REGULATORY OFF GAS EMISSIONS TESTING ON THE DM1200 MELTER SYSTEM USING HLW AND LAW SIMULANTS VSL-05R5830-1 REV 0 10/31/05

Energy Technology Data Exchange (ETDEWEB)

KRUGER AA; MATLACK KS; GONG W; BARDAKCI T; D' ANGELO NA; BRANDYS M; KOT WK; PEGG IL

2011-12-29

The operational requirements for the River Protection Project - Waste Treatment Plant (RPP-WTP) Low Activity Waste (LAW) and High Level Waste (HLW) melter systems, together with the feed constituents, impose a number of challenges to the off-gas treatment system. The system must be robust from the standpoints of operational reliability and minimization of maintenance. The system must effectively control and remove a wide range of solid particulate matter, acid mists and gases, and organic constituents (including those arising from products of incomplete combustion of sugar and organics in the feed) to concentration levels below those imposed by regulatory requirements. The baseline design for the RPP-WTP LAW primary off-gas system includes a submerged bed scrubber (SBS), a wet electrostatic precipitator (WESP), and a high efficiency particulate air (HEPA) filter. The secondary off-gas system includes a sulfur-impregnated activated carbon bed (AC-S), a thermal catalytic oxidizer (TCO), a single-stage selective catalytic reduction NOx treatment system (SCR), and a packed-bed caustic scrubber (PBS). The baseline design for the RPP-WTP HLW primary off-gas system includes an SBS, a WESP, a high efficiency mist eliminator (HEME), and a HEPA filter. The HLW secondary off-gas system includes a sulfur-impregnated activated carbon bed, a silver mordenite bed, a TCO, and a single-stage SCR. The one-third scale HLW DM1200 Pilot Melter installed at the Vitreous State Laboratory (VSL) was equipped with a prototypical off-gas train to meet the needs for testing and confirmation of the performance of the baseline off-gas system design. Various modifications have been made to the DM1200 system as the details of the WTP design have evolved, including the installation of a silver mordenite column and an AC-S column for testing on a slipstream of the off-gas flow; the installation of a full-flow AC-S bed for the present tests was completed prior to initiation of testing. The DM1200

Development and testing of prototype alpha waste incinerator off-gas systems

International Nuclear Information System (INIS)

Freed, E.J.; Becker, G.W.

1982-01-01

A test program is in progress at Savannah River Laboratory (SRL) to confirm and develop incinerator design technology for an SRP production Alpha Waste Incinerator (AWI) to be built in the mid-1980's. The Incinerator Components Test Facility (ICTF) is a full-scale (5 kg/h), electrically heated, controlled-air prototype incinerator built to burn nonradioactive solid waste. The incinerator has been operating successfully at SRL since March 1979 and has met or exceeded all design criteria. During the first 1-1/2 years of operation, liquid scrubbers were used to remove particulates and hydrochloric acid from the incinerator exhaust gases. A dry off-gas system is currently being tested to provide data to Savannah River Plant's proposed AWI

Proposed Strategies for DWPF Melter Off-Gas Surge Control

International Nuclear Information System (INIS)

CHOI, ALEXANDERS.

2004-01-01

Off-gas surging is inherent to the operation of slurry-fed melters. Although the melter design and the feed chemistry are both known to significantly affect off-gas surging, the frequency and intensity of surges are in essence unpredictable. In typical off-gas surges, both condensable and non condensable flows spike simultaneously. Condensable or steam surges have been observed to occur as the boiling water layer occasionally falls into the crevices of the cold cap or flows over the edges of the cold cap, thereby coming in contact with the melt surface. The resulting steam surges can pressurize the melter considerably and, therefore, are responsible for the bulk of pressure transients that propagate throughout the off-gas system. The non condensable surges occur as the calcine gases that have been accumulating within the cold cap finally build up enough pressure to be released through the temporary openings of the cold cap. The analysis of off-gas data has shown that over 90 of the gas released during a surge is due to steam.1 Therefore, it is essential to have a large inventory of water in the cold cap for any significant pressure spikes to occur. With the Melter 2 vapor space temperature typically running at 720C, the water layer in the cold cap will quickly evaporate once the feeding stops, and the potential for any large pressure spikes should practically cease to exist. The analysis also showed that large pressure spikes well above 2 inches H2O cannot occur under the steam surge scenarios described above. More severe conditions should prevail and one such condition would be that the feed materials form a mound with a growing lake on top, while the melt below remains very fluidic due to its low viscosity, thus resulting in greater movements both in the lateral as well as vertical directions. Once the mound begins to grow, its rate should accelerate, since the heat transfer rate to the upper regions of the cold cap is inversely proportional to the cold cap

Fluidized-bed calcination of LWR fuel-reprocessing HLLW: requirements and potential for off-gas cleanup

International Nuclear Information System (INIS)

Schindler, R.E.

1979-01-01

Fluidized-bed solidification (calcination) was developed on a pilot scale for a variety of simulated LWR high-level liquid-waste (HLLW) and blended high-level and intermediate-level liquid-waste (ILLW) compositions. It has also been demonstrated with ICPP fuel-reprocessing waste since 1963 in the Waste Calcining Facility (WCF) at gross feed rates of 5 to 12 m 3 /day. A fluidized-bed calciner produces a relatively large volume of off-gas. A calciner solidifying 6 m 3 /day of liquid waste would generate about 13 standard m 3 /min of off-gas containing 10 to 20 g of entrained solids per standard m 3 of off-gas. Use of an off-gas system similar to that of the WCF could provide an overall process decontamination factor for particulates of about 2 x 10 10 . A potential advantage of fluidized-bed calcination over other solidification methods is the ability to control ruthenium volatilization from the calciner at less than 0.01% by calcining at 500 0 C or above. Use of an off-gas system similar to that of the WCF would provide an overall process decontamination factor for volatile ruthenium of greater than 1.6 x 10 7

Computer simulation of the off gas treatment process for the KEPCO pilot vitrification plant

International Nuclear Information System (INIS)

Kim, Hey Suk; Maeng, Sung Jun; Lee, Myung Chan

1999-01-01

Vitrification technology for treatment of low and intermediate radioactive wastes can remarkably reduce waste volume to about one twentieth of the initial volume as they are collected and converted into a very stable form. Therefore, it can minimize environmental impact when the vitrified waste is disposed of. But an off gas treatment system is necessary to apply this technology because air pollutants and radioisotopes are generated like those of other conventional incinerators during thermal oxidation process at high temperature. KEPCO designed and installed a pilot scale vitrification plant to demonstrate the feasibility of the vitrification process and then to make a conceptual design for a commercial vitrification facility. The purpose of this study was to simulate the off gas treatment system(OGTS) in order optimize the operating conditions. Mass balance and temperature profile in the off gas treatment system were simulated for different combinations of combustible wastes by computer simulation code named OGTS code and removal efficiency of each process was also calculated with change of design parameters. The OGTS code saved efforts,time and capital because scale and configuration of the system could be easily changed. The simulation result of the pilot scale off gas process as well as pilot tests will be of great use in the future for a design of the commercial vitrification facility. (author)

Adsorptive separation of NOsub(x) from dissolver off-gas

International Nuclear Information System (INIS)

Ringel, H.

1984-06-01

After precleaning the dissolver off-gas contains, besides the noble gases Xe and Kr, about 0.5 vol.% each of NOsub(x) and H 2 O. For the removal of these NOsub(x) and H 2 O residues to below 1 ppm, an adsorptive gas cleaning process has been developed and tested on a lab-scale. For the process, an acid resistant molecular sieve was selected and its properties investigated with respect to application; e.g. the dependence of the adsorption capacity on temperature, gas composition and face velocity. By the operation of a lab-scale facility with 400 Nl/h continuous off-gas throughput the suitability of the adsorption process has been demonstrated for off-gas cleaning and recycling of the separated NO 2 and H 2 O to the dissolver. (orig.) [de

Test results in the treatment of HTR reprocessing off-gas

International Nuclear Information System (INIS)

Barnert-Wiemer, H.; Bendick, B.; Juergens, B.; Nafissi, A.; Vygen, H.; Krill, W.

1983-01-01

The AKUT II-facility (throughput 10 m 3 /h, STP) for the clean up of the burner off-gas has been tested with synthetic off-gas and with off-gas from cold burner tests. The results are reported. During dissolution of the burner ash in nitric acid an off-gas is formed whose main component is air and which, besides the gaseous fission products, contains NO/sub x/. Before the separation of the gaseous fission products NO/sub x/ and/or O 2 are removed by reaction with H 2 or NH 3 . For these reactions catalysts were used. Because of the known disadvantages of catalytic systems, like reduction in efficiency by poisoning or thermal influence, the alternative method of thermal, flameless reduction was tested. The reactions were carried out in a stainless steel and a quartz reactor. Throughput, reaction temperature, O 2 -, NO/sub x/-, H 2 -, and NH 3 -concentrations respectively were varied. The goal of these tests was to remove O 2 and NO/sub x/ to below 1 ppM behind the reactor and NH 3 to below the detection limit of 50 ppM. It was found that at a reaction temperature of 750 0 C in the stainless steel reactor these goals can be reached for both H 2 and NH 3 as reducing agents. In the quartz reactor only the O 2 -H 2 -reaction takes place. Obviously stainless steel acts as a catalyst for all other reactions

Design and optimization of a combined fuel reforming and solid oxide fuel cell system with anode off-gas recycling

International Nuclear Information System (INIS)

Lee, Tae Seok; Chung, J.N.; Chen, Yen-Cho

2011-01-01

Highlights: → In this work, an analytical, parametric study is performed to evaluate the feasibility and performance of a combined fuel reforming and SOFC system. → Specifically the effects of adding the anode off-gas recycling and recirculation components and the CO 2 absorbent unit are investigated. → The AOG recycle ratio increases with increasing S/C ratio and the addition of AOG recycle eliminates the need for external water consumption. → The key finding is that for the SOFC operating at 900 deg. C with the steam to carbon ratio at 5 and no AOG recirculation, the system efficiency peaks. - Abstract: An energy conversion and management concept for a combined system of a solid oxide fuel cell coupled with a fuel reforming device is developed and analyzed by a thermodynamic and electrochemical model. The model is verified by an experiment and then used to evaluate the overall system performance and to further suggest an optimal design strategy. The unique feature of the system is the inclusion of the anode off-gas recycle that eliminates the need of external water consumption for practical applications. The system performance is evaluated as a function of the steam to carbon ratio, fuel cell temperature, anode off gas recycle ratio and CO 2 adsorption percentage. For most of the operating conditions investigated, the system efficiency starts at around 70% and then monotonically decreases to the average of 50% at the peak power density before dropping down to zero at the limiting current density point. From an engineering application point of view, the proposed combined fuel reforming and SOFC system with a range of efficiency between 50% and 70% is considered very attractive. It is suggested that the optimal system is the one where the SOFC operates around 900 deg. C with S/C ratio higher than 3, maximum CO 2 capture, and minimum AOG recirculation.

Development of silver impregnated alumina for iodine separation from off-gas streams

Energy Technology Data Exchange (ETDEWEB)

Funabashi, Kiyomi; Fukasawa, Tetsuo; Kikuchi, Makoto [Energy Research Laboratory, Hitachi (Japan)] [and others

1995-02-01

An inorganic iodine adsorbent, silver impregnated alumina (AgA), has been developed to separate iodine effectively from off-gas streams of nuclear facilities and to decrease the volume of waste (spent adsorbent). Iodine removal efficiency was improved at relatively high humidity by using alumina carrier with two different pore diameters. Waste volume reduction was achieved by impregnating relatively large amounts of silver into the alumina pores. The developed adsorbent was tested first with simulated off-gas streams under various experimental conditions and finally with actual off-gas streams of the Karlsruhe reprocessing plant. The decontamination factor (DF) was about 100 with the AgA bed depth of 2cm at 70% relative humidity, which was a DF one order higher than that when AgA with one pore size was used. Iodine adsorption capacity was checked by passing excess iodine into the AgA bed. Values were about 0.12 and 0.35 g-I/cm`-AgA bed for 10 and 24wt% silver impregnated AgA, respectively. The results obtained in this study demonstrated the applicability of the developed AgA to the off-gas treatment system of nuclear facilities.

Organic Iodine Adsorption by AgZ under Prototypical Vessel Off-Gas Conditions

International Nuclear Information System (INIS)

Bruffey, Stephanie H.; Jubin, Robert Thomas; Jordan, J. A.

2016-01-01

U.S. regulations will require the removal of 129 I from the off-gas streams of any used nuclear fuel (UNF) reprocessing plant prior to discharge of the off-gas to the environment. Multiple off-gas streams within a UNF reprocessing plant combine prior to release, and each of these streams contains some amount of iodine. For an aqueous UNF reprocessing plant, these streams include the dissolver off-gas, the cell off-gas, the vessel off-gas (VOG), the waste off-gas and the shear off-gas. To achieve regulatory compliance, treatment of multiple off-gas streams within the plant must be performed. Preliminary studies have been completed on the adsorption of I 2 onto silver mordenite (AgZ) from prototypical VOG streams. The study reported that AgZ did adsorb I 2 from a prototypical VOG stream, but process upsets resulted in an uneven feed stream concentration. The experiments described in this document both improve the characterization of I 2 adsorption by AgZ from dilute gas streams and further extend it to include characterization of the adsorption of organic iodides (in the form of CH 3 I) onto AgZ under prototypical VOG conditions. The design of this extended duration testing was such that information about the rate of adsorption, the penetration of the iodine species, and the effect of sorbent aging on iodine removal in VOG conditions could be inferred.

Organic Iodine Adsorption by AgZ under Prototypical Vessel Off-Gas Conditions

Energy Technology Data Exchange (ETDEWEB)

Bruffey, Stephanie H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jubin, Robert Thomas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jordan, J. A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2016-09-30

U.S. regulations will require the removal of ¹²⁹I from the off-gas streams of any used nuclear fuel (UNF) reprocessing plant prior to discharge of the off-gas to the environment. Multiple off-gas streams within a UNF reprocessing plant combine prior to release, and each of these streams contains some amount of iodine. For an aqueous UNF reprocessing plant, these streams include the dissolver off-gas, the cell off-gas, the vessel off-gas (VOG), the waste off-gas and the shear off-gas. To achieve regulatory compliance, treatment of multiple off-gas streams within the plant must be performed. Preliminary studies have been completed on the adsorption of I₂ onto silver mordenite (AgZ) from prototypical VOG streams. The study reported that AgZ did adsorb I₂ from a prototypical VOG stream, but process upsets resulted in an uneven feed stream concentration. The experiments described in this document both improve the characterization of I₂ adsorption by AgZ from dilute gas streams and further extend it to include characterization of the adsorption of organic iodides (in the form of CH₃I) onto AgZ under prototypical VOG conditions. The design of this extended duration testing was such that information about the rate of adsorption, the penetration of the iodine species, and the effect of sorbent aging on iodine removal in VOG conditions could be inferred.

Method for treating a nuclear process off-gas stream

International Nuclear Information System (INIS)

Pence, D.T.; Chou, C.-C.

1981-01-01

A method is described for selectively removing and recovering the noble gas and other gaseous components typically emitted during nuclear process operations. The method is useful for treating dissolver off-gas effluents released during reprocessing of spent nuclear fuels to permit radioactive contaminant recovery prior to releasing the remaining off-gases to the atmosphere. The method involves a sequence of adsorption and desorption steps which are specified. Particular reference is made to the separation of xenon and krypton from the off-gas stream, and to the use of silver-exchanged mordenite as the adsorbent. (U.K.)

Treatment Of Mercury Target Off-Gas At SNS

International Nuclear Information System (INIS)

DeVore, Joe R.; Freeman, David W.

2007-01-01

The Spallation Neutron Source (SNS) is the first operational spallation source to use liquid Mercury as a target material. This paper describes the treatment system to remove volatile spallation products from a Helium purge stream that emanates from the Mercury target and adjustments made to achieve design goals in response to phenomena experienced during initial operations. The Helium stream is treated to remove volatile spallation products prior to environmental release because of its activity level as these accumulate in the gas space in the Mercury Loop. Unanticipated local dose rates were noted in treatment system components during low power startup. Gamma scanning of these components identified the presence of nineteen noble gas isotopes and their daughters, indicating that the doses resulted from noble gas sorption. Treatment of this equipment with stable Xenon greatly reduced but did not eliminate these. Significant moisture was also encountered in the system, resulting in the plugging of the system cold trap. Changes to some of the system equipment were required together with moisture elimination from components to which moisture was sorbed. Necessary re-configuration of Mercury pump components presented additional requirements and system control changes to accommodate system operation at reduced pressure. The Off-Gas Treatment System has been successfully operated since April, 2006. System availability and removal effectiveness have been high. Operational issues occurring during the first year of operation have been resolved.

Olefin recovery from FCC off-gas can pay off

International Nuclear Information System (INIS)

Brahn, M.G.

1992-01-01

This paper reports on olefins recovery from refinery FCC offgas streams which offers an attractive cash flow from olefins from a tail-gas stream that has typically been consumed as refinery fuel. Such recovery schemes can be employed in refineries or olefins plants, and can be tailored to fit individual requirements. Mobil Chemical Co. has operated such a dephlegmator-based off-gas recovery unit at its Beaumont, Tex., olefin plant since 1987. It reported that the project was paid out within 11 months of initial start-up

Radon depletion in xenon boil-off gas

Energy Technology Data Exchange (ETDEWEB)

Bruenner, S.; Cichon, D.; Lindemann, S.; Undagoitia, T.M.; Simgen, H. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany)

2017-03-15

An important background in detectors using liquid xenon for rare event searches arises from the decays of radon and its daughters. We report for the first time a reduction of {sup 222}Rn in the gas phase above a liquid xenon reservoir. We show a reduction factor of >or similar 4 for the {sup 222}Rn concentration in boil-off xenon gas compared to the radon enriched liquid phase. A semiconductor-based α-detector and miniaturized proportional counters are used to detect the radon. As the radon depletion in the boil-off gas is understood as a single-stage distillation process, this result establishes the suitability of cryogenic distillation to separate radon from xenon down to the 10{sup -15} mol/mol level. (orig.)

Absorption process for removing krypton from the off-gas of an LMFBR fuel reprocessing plant

International Nuclear Information System (INIS)

Stephenson, M.J.; Dunthorn, D.I.; Reed, W.D.; Pashley, J.H.

1975-01-01

The Oak Ridge Gaseous Diffusion Plant selective absorption process for the collection and recovery of krypton and xenon is being further developed to demonstrate, on a pilot scale, a fluorocarbon-based process for removing krypton from the off-gas of an LMFBR fuel reprocessing plant. The new ORGDP selective absorption pilot plant consists of a primary absorption-stripping operation and all peripheral equipment required for feed gas preparation, process solvent recovery, process solvent purification, and krypton product purification. The new plant is designed to achieve krypton decontamination factors in excess of 10 3 with product concentration factors greater than 10 4 while processing a feed gas containing typical quantities of common reprocessing plant off-gas impurities, including oxygen, carbon dioxide, nitrogen oxides, water, xenon, iodine, and methyl iodide. Installation and shakedown of the facility were completed and some short-term tests were conducted early this year. The first operating campaign using a simulated reprocessing plant off-gas feed is now underway. The current program objective is to demonstrate continuous process operability and performance for extended periods of time while processing the simulated ''dirty'' feed. This year's activity will be devoted to routine off-gas processing with little or no deliberate system perturbations. Future work will involve the study of the system behavior under feed perturbations and various plant disturbances. (U.S.)

Linking environment-productivity trade-offs and correlated uncertainties: Greenhouse gas emissions and crop productivity in paddy rice production systems

International Nuclear Information System (INIS)

Hayashi, Kiyotada; Nagumo, Yoshifumi; Domoto, Akiko

2016-01-01

In comparative life cycle assessments of agricultural production systems, analyses of both the trade-offs between environmental impacts and crop productivity and of the uncertainties specific to agriculture such as fluctuations in greenhouse gas (GHG) emissions and crop yields are crucial. However, these two issues are usually analyzed separately. In this paper, we present a framework to link trade-off and uncertainty analyses; correlated uncertainties are integrated into environment-productivity trade-off analyses. We compared three rice production systems in Japan: a system using a pelletized, nitrogen-concentrated organic fertilizer made from poultry manure using closed-air composting techniques (high-N system), a system using a conventional organic fertilizer made from poultry manure using open-air composting techniques (low-N system), and a system using a chemical compound fertilizer (conventional system). We focused on two important sources of uncertainties in paddy rice cultivation—methane emissions from paddy fields and crop yields. We found trade-offs between the conventional and high-N systems and the low-N system and the existence of positively correlated uncertainties in the conventional and high-N systems. We concluded that our framework is effective in recommending the high-N system compared with the low-N system, although the performance of the former is almost the same as the conventional system. - Highlights: • Correlated uncertainties were integrated into environment-productivity trade-offs. • Life cycle GHG emissions and crop yields were analyzed using field and survey data. • Three rice production systems using chemical or organic fertilizers were compared. • There were portfolio (insurance) effects in matured technologies. • Analysis of trade-offs and correlated uncertainties will be useful for decisions.

Linking environment-productivity trade-offs and correlated uncertainties: Greenhouse gas emissions and crop productivity in paddy rice production systems

Energy Technology Data Exchange (ETDEWEB)

Hayashi, Kiyotada, E-mail: hayashi@affrc.go.jp [Institute for Agro-Environmental Sciences, National Agriculture and Food Research Organization, 3-1-3 Kannondai, Tsukuba, Ibaraki 305-8604 (Japan); Nagumo, Yoshifumi [Crop Research Center, Niigata Agricultural Research Institute, 857 Nagakura-machi, Nagaoka, Niigata 940-0826 (Japan); Domoto, Akiko [Mie Prefecture Agricultural Research Institute, 530 Kawakita-cho, Ureshino, Matsusaka, Mie 515-2316 (Japan)

2016-11-15

In comparative life cycle assessments of agricultural production systems, analyses of both the trade-offs between environmental impacts and crop productivity and of the uncertainties specific to agriculture such as fluctuations in greenhouse gas (GHG) emissions and crop yields are crucial. However, these two issues are usually analyzed separately. In this paper, we present a framework to link trade-off and uncertainty analyses; correlated uncertainties are integrated into environment-productivity trade-off analyses. We compared three rice production systems in Japan: a system using a pelletized, nitrogen-concentrated organic fertilizer made from poultry manure using closed-air composting techniques (high-N system), a system using a conventional organic fertilizer made from poultry manure using open-air composting techniques (low-N system), and a system using a chemical compound fertilizer (conventional system). We focused on two important sources of uncertainties in paddy rice cultivation—methane emissions from paddy fields and crop yields. We found trade-offs between the conventional and high-N systems and the low-N system and the existence of positively correlated uncertainties in the conventional and high-N systems. We concluded that our framework is effective in recommending the high-N system compared with the low-N system, although the performance of the former is almost the same as the conventional system. - Highlights: • Correlated uncertainties were integrated into environment-productivity trade-offs. • Life cycle GHG emissions and crop yields were analyzed using field and survey data. • Three rice production systems using chemical or organic fertilizers were compared. • There were portfolio (insurance) effects in matured technologies. • Analysis of trade-offs and correlated uncertainties will be useful for decisions.

Method for treating a nuclear process off-gas stream

International Nuclear Information System (INIS)

Pence, D.T.; Chou, C.C.

1984-01-01

Disclosed is a method for selectively removing and recovering the noble gas and other gaseous components typically emitted during nuclear process operations. The method is adaptable and useful for treating dissolver off-gas effluents released during reprocessing of spent nuclear fuels whereby to permit radioactive contaminant recovery prior to releasing the remaining off-gases to the atmosphere. Briefly, the method sequentially comprises treating the off-gas stream to preliminarily remove NO /SUB x/ , hydrogen and carbon-containing organic compounds, and semivolatile fission product metal oxide components therefrom; adsorbing iodine components on silver-exchanged mordenite; removing water vapor carried by said stream by means of a molecular sieve; selectively removing the carbon dioxide components of said off-gas stream by means of a molecular sieve; selectively removing xenon in gas phase by passing said stream through a molecular sieve comprising silver-exchanged mordenite; selectively separating krypton from oxygen by means of a molecular sieve comprising silver-exchanged mordenite; selectively separating krypton from the bulk nitrogen stream using a molecular sieve comprising silver-exchanged mordenite cooled to about -140 0 to -160 0 C.; concentrating the desorbed krypton upon a molecular sieve comprising silver-exchange mordenite cooled to about -140 0 to -160 0 C.; and further cryogenically concentrating, and the recovering for storage, the desorbed krypton

Method for treating a nuclear process off-gas stream

Science.gov (United States)

Pence, Dallas T.; Chou, Chun-Chao

1984-01-01

Disclosed is a method for selectively removing and recovering the noble gas and other gaseous components typically emitted during nuclear process operations. The method is adaptable and useful for treating dissolver off-gas effluents released during reprocessing of spent nuclear fuels whereby to permit radioactive contaminant recovery prior to releasing the remaining off-gases to the atmosphere. Briefly, the method sequentially comprises treating the off-gas stream to preliminarily remove NO.sub.x, hydrogen and carbon-containing organic compounds, and semivolatile fission product metal oxide components therefrom; adsorbing iodine components on silver-exchanged mordenite; removing water vapor carried by said stream by means of a molecular sieve; selectively removing the carbon dioxide components of said off-gas stream by means of a molecular sieve; selectively removing xenon in gas phase by passing said stream through a molecular sieve comprising silver-exchanged mordenite; selectively separating krypton from oxygen by means of a molecular sieve comprising silver-exchanged mordenite; selectively separating krypton from the bulk nitrogen stream using a molecular sieve comprising silver-exchanged mordenite cooled to about -140.degree. to -160.degree. C.; concentrating the desorbed krypton upon a molecular sieve comprising silver-exchange mordenite cooled to about -140.degree. to -160.degree. C.; and further cryogenically concentrating, and the recovering for storage, the desorbed krypton.

Dynamic performance of a combined gas turbine and air bottoming cycle plant for off-shore applications

DEFF Research Database (Denmark)

Benato, Alberto; Pierobon, Leonardo; Haglind, Fredrik

2014-01-01

and a combined gas turbine coupled with an air bottoming cycle plant. The case study is the Draugen off-shore oil and gas platform, located in the North Sea, Norway. The normal electricity demand is 19 MW, currently covered by two gas turbines generating each 50% of the power demand, while the third turbine......When the Norwegian government introduced the CO2 tax for hydrocarbon fuels, the challenge became to improve the performance of off-shore power systems. An oil and gas platform typically operates on an island (stand-alone system) and the power demand is covered by two or more gas turbines. In order...... to improve the plant performance, a bottoming cycle unit can be added to the gas turbine topping module, thus constituting a combined cycle plant. This paper aims at developing and testing the numerical model simulating the part-load and dynamic behavior of a novel power system, composed of two gas turbines...

Improvement of melter off-gas design for commercial HALW vitrification facility

Energy Technology Data Exchange (ETDEWEB)

Ohno, A.; Kitamura, M.; Yamanaka, T. [Ishikawajima-Harima Heavy Industries Co., Ltd., Yokohama (Japan); Yoshioka, M.; Endo, N.; Asano, N. [Japan Nuclear Cycle Development Institute, Ibaraki (Japan)

2001-07-01

The Japan commercial reprocessing plant is now under construction, and it will commence the operation in 2005. The High Active Liquid Waste (HALW) generated at the plant is treated into glass product at the vitrification facility using the Liquid Fed Joule-Heated Ceramic Melter (LFCM). The characteristic of the LFCM is that the HALW is fed directly onto the molten glass surface with the glass forming material. This process was developed by the Japan Nuclear Cycle Development Institute (JNC). The JNC process was first applied to the Tokai Vitrification Facility (TVF), which is a pilot scale plant having about 1/6 capacity of the commercial facility. The TVF has been in operation since 1995. During the operation, the rapid increase of the differential pressure between the melter plenum and the dust scrubber was observed. This phenomenon is harmful to the long-term continuous operation of TVF. And, it is also anticipated that the same phenomenon will occur in commercial vitrification facility. In order to solve this problem, the countermeasures were studied and developed. Through the study on the deposit growing mechanism, it was probable that the rapid increased differential pressure was attributed to the condensation of meta-boric acid at the outlet of the air-film cooler slits. And, the heating and the humidification of purge air were judged to be effective as the countermeasures to suppress the condensation. On the other hand, the water injection into melter off-gas pipe was found to be very effective to reduce the differential pressure as the results of the various tests. The deposit adhered on the inner surface of the off-gas pipe was almost washed out. And, it was also demonstrated that the system was superior to other systems by virtue of its simplicity and stability. In order to apply the system to the commercial scale plant, the scale-up tests were conducted at JNC mock-up facility using the acrylic model. (author)

Improvement of melter off-gas design for commercial HALW vitrification facility

International Nuclear Information System (INIS)

Ohno, A.; Kitamura, M.; Yamanaka, T.; Yoshioka, M.; Endo, N.; Asano, N.

2001-01-01

The Japan commercial reprocessing plant is now under construction, and it will commence the operation in 2005. The High Active Liquid Waste (HALW) generated at the plant is treated into glass product at the vitrification facility using the Liquid Fed Joule-Heated Ceramic Melter (LFCM). The characteristic of the LFCM is that the HALW is fed directly onto the molten glass surface with the glass forming material. This process was developed by the Japan Nuclear Cycle Development Institute (JNC). The JNC process was first applied to the Tokai Vitrification Facility (TVF), which is a pilot scale plant having about 1/6 capacity of the commercial facility. The TVF has been in operation since 1995. During the operation, the rapid increase of the differential pressure between the melter plenum and the dust scrubber was observed. This phenomenon is harmful to the long-term continuous operation of TVF. And, it is also anticipated that the same phenomenon will occur in commercial vitrification facility. In order to solve this problem, the countermeasures were studied and developed. Through the study on the deposit growing mechanism, it was probable that the rapid increased differential pressure was attributed to the condensation of meta-boric acid at the outlet of the air-film cooler slits. And, the heating and the humidification of purge air were judged to be effective as the countermeasures to suppress the condensation. On the other hand, the water injection into melter off-gas pipe was found to be very effective to reduce the differential pressure as the results of the various tests. The deposit adhered on the inner surface of the off-gas pipe was almost washed out. And, it was also demonstrated that the system was superior to other systems by virtue of its simplicity and stability. In order to apply the system to the commercial scale plant, the scale-up tests were conducted at JNC mock-up facility using the acrylic model. (author)

Commercial application of titania-supported hydrodesulfurization catalysts in the production of hydrogen using full-range FCC off-gas

Energy Technology Data Exchange (ETDEWEB)

Wang, Shaohu [SINOPEC Wuhan Branch, Qingshan, Wuhan 430082 (China); Shen, Binglong; Qu, Lianglong [Beijing Haishunde Titanium Catalyst Co. Ltd., A-1 North East-Ring Road, Beijing Economic-Technological Development Area, Beijing 100176 (China)

2004-11-24

This paper provides an alternative for low-cost feed used for on-purpose hydrogen production. Full-range FCC off-gas was applied to steam-reforming process as feed after treating with hydrogenation and hydrodesulfurization catalysts. Commercial run results were reported with novel TiO{sub 2}-supported Mo-based catalysts, T205A-1 and T205. The processes of catalysts loading, sulfidation, start-up and long-term run were described in details. Long-term run showed that TiO{sub 2}-supported Mo catalysts have good low-temperature hydrogenation activity, excellent HDS activity, and outstanding stability. Use of FCC off-gas as feed for hydrogen production is quite promising and will increase margins for refiners today.

Analysis of Off Gas From Disintegration Process of Graphite Matrix by Electrochemical Method

International Nuclear Information System (INIS)

Tian Lifang; Wen Mingfen; Chen Jing

2010-01-01

Using electrochemical method with salt solutions as electrolyte, some gaseous substances (off gas) would be generated during the disintegration of graphite from high-temperature gas-cooled reactor fuel elements. The off gas is determined to be composed of H 2 , O 2 , N 2 , CO 2 and NO x by gas chromatography. Only about 1.5% graphite matrix is oxidized to CO 2 . Compared to the direct burning-graphite method, less off gas,especially CO 2 , is generated in the disintegration process of graphite by electrochemical method and the treatment of off gas becomes much easier. (authors)

Hanford Low-Activity Waste Processing: Demonstration of the Off-Gas Recycle Flowsheet - 13443

Energy Technology Data Exchange (ETDEWEB)

Ramsey, William G.; Esparza, Brian P. [Washington River Protection Solutions, LLC, Richland, WA 99532 (United States)

2013-07-01

Vitrification of Hanford Low-Activity Waste (LAW) is nominally the thermal conversion and incorporation of sodium salts and radionuclides into borosilicate glass. One key radionuclide present in LAW is technetium-99. Technetium-99 is a low energy, long-lived beta emitting radionuclide present in the waste feed in concentrations on the order of 1-10 ppm. The long half-life combined with a high solubility in groundwater results in technetium-99 having considerable impact on performance modeling (as potential release to the environment) of both the waste glass and associated secondary waste products. The current Hanford Tank Waste Treatment and Immobilization Plant (WTP) process flowsheet calls for the recycle of vitrification process off-gas condensates to maximize the portion of technetium ultimately immobilized in the waste glass. This is required as technetium acts as a semi-volatile specie, i.e. considerable loss of the radionuclide to the process off-gas stream can occur during the vitrification process. To test the process flowsheet assumptions, a prototypic off-gas system with recycle capability was added to a laboratory melter (on the order of 1/200 scale) and testing performed. Key test goals included determination of the process mass balance for technetium, a non-radioactive surrogate (rhenium), and other soluble species (sulfate, halides, etc.) which are concentrated by recycling off-gas condensates. The studies performed are the initial demonstrations of process recycle for this type of liquid-fed melter system. This paper describes the process recycle system, the waste feeds processed, and experimental results. Comparisons between data gathered using process recycle and previous single pass melter testing as well as mathematical modeling simulations are also provided. (authors)

Comparison between reverse Brayton and Kapitza based LNG boil-off gas reliquefaction system using exergy analysis

Science.gov (United States)

Kochunni, Sarun Kumar; Chowdhury, Kanchan

2017-02-01

LNG boil-off gas (BOG) reliquefaction systems in LNG carrier ships uses refrigeration devices which are based on reverse Brayton, Claude, Kapitza (modified Claude) or Cascade cycles. Some of these refrigeration devices use nitrogen as the refrigerants and hence nitrogen storage vessels or nitrogen generators needs to be installed in LNG carrier ships which consume space and add weight to the carrier. In the present work, a new configuration based on Kapitza liquefaction cycle which uses BOG itself as working fluid is proposed and has been compared with Reverse Brayton Cycle (RBC) on sizes of heat exchangers and compressor operating parameters. Exergy analysis is done after simulating at steady state with Aspen Hysys 8.6® and the comparison between RBC and Kapitza may help designers to choose reliquefaction system with appropriate process parameters and sizes of equipment. With comparable exergetic efficiency as that of an RBC, a Kaptiza system needs only BOG compressor without any need of nitrogen gas.

Stabilization of gas turbine unit power

Science.gov (United States)

Dolotovskii, I.; Larin, E.

2017-11-01

We propose a new cycle air preparation unit which helps increasing energy power of gas turbine units (GTU) operating as a part of combined cycle gas turbine (CCGT) units of thermal power stations and energy and water supply systems of industrial enterprises as well as reducing power loss of gas turbine engines of process blowers resulting from variable ambient air temperatures. Installation of GTU power stabilizer at CCGT unit with electric and thermal power of 192 and 163 MW, respectively, has resulted in reduction of produced electrical energy production costs by 2.4% and thermal energy production costs by 1.6% while capital expenditures after installation of this equipment increased insignificantly.

Off-gas treatment carbon footprint calculator : form and function

Energy Technology Data Exchange (ETDEWEB)

Kessell, L. [Good EarthKeeping Organization Inc., Corona, CA (United States); Squire, J.; Crosby, K. [Haley and Aldrich Inc., Boston, MA (United States)

2008-07-01

Carbon footprinting is the measurement of the impact on the environment in terms of the amount of greenhouse gases produced, measured in units of carbon dioxide released directly and indirectly by an individual, organization, process, event or product. This presentation discussed an off-gas treatment carbon footprint calculator. The presentation provided a review of off-gas treatment technologies and presented a carbon footprint model. The model included: form and function; parameters; assumptions; calculations; and off-gas treatment applications. Parameters of the model included greenhouse gases listed in the Kyoto Protocol to the United Nations Framework Convention on Climate Change, such as carbon dioxide, methane, nitrous oxide, sulfur hexafluoride, hydrofluorocarbons, and perfluorocarbons. Assumptions of the model included stationary combustion emissions; mobile combustion emissions; indirect emissions; physical or chemical processing emissions; fugitive emissions; and de minimus emissions. The presentation also examined resource conservation and discussed three greenhouse gas footprint case studies. It was concluded that the model involved a calculator with standard calculations with clearly defined assumptions with boundaries. tabs., figs.

Design of a boil-off natural gas reliquefaction control system for LNG carriers

International Nuclear Information System (INIS)

Shin, Younggy; Lee, Yoon Pyo

2009-01-01

Onboard boil-off gas (BOG) reliquefaction is a new technology that liquefies BOG and returns it to the cargo tanks instead of burning it off during a voyage. For the commercial development of this technology, an object-oriented dynamic simulation is presented which facilitates the design of the plant and control system for the thermal process. A reliquefaction process based on the reverse Brayton cycle has been designed, and its static thermodynamic states at the design BOG load are presented. To make the cycle work for any BOG load, an idea was sought that would achieve a heat balance with the work extracted by the expander. Dynamic simulations were conducted for all operating modes, including start-up and idle. It was found that the expander exit temperature is the key process variable for control and that the process control works successfully when three actuators are activated in three different BOG load regimes. The study also shows that control of the separator pressure to keep the vapor fraction at the throttle valve exit as low as possible is an efficient method for purging nitrogen from BOG

Gas-Solid Reaction Properties of Fluorine Compounds and Solid Adsorbents for Off-Gas Treatment from Semiconductor Facility

Directory of Open Access Journals (Sweden)

Shinji Yasui

2012-01-01

Full Text Available We have been developing a new dry-type off-gas treatment system for recycling fluorine from perfluoro compounds present in off-gases from the semiconductor industry. The feature of this system is to adsorb the fluorine compounds in the exhaust gases from the decomposition furnace by using two types of solid adsorbents: the calcium carbonate in the upper layer adsorbs HF and converts it to CaF2, and the sodium bicarbonate in the lower layer adsorbs HF and SiF4 and converts them to Na2SiF6. This paper describes the fluorine compound adsorption properties of both the solid adsorbents—calcium carbonate and the sodium compound—for the optimal design of the fixation furnace. An analysis of the gas-solid reaction rate was performed from the experimental results of the breakthrough curve by using a fixed-bed reaction model, and the reaction rate constants and adsorption capacity were obtained for achieving an optimal process design.

Iodine and NOx behavior in the dissolver off-gas and IODOX [Iodine Oxidation] systems in the Oak Ridge National Laboratory Integrated Equipment Test facility

International Nuclear Information System (INIS)

Birdwell, J.F.

1990-01-01

This paper describes the most recent in a series of experiments evaluating the behavior of iodine and NO x in the Integrated Equipment Test (IET) Dissolver Off-Gas (DOG) System. This work was performed as part of a joint collaborative program between the US Department of Energy and the Power and Nuclear Fuel Development Corporation of Japan. The DOG system consists of two shell-and-tube heat exchangers in which water and nitric acid are removed from the dissolver off-gas by condensation, followed by a packed tower in which NO x is removed by absorption into a dilute nitric acid solution. The paper also describes the results of the operation of the Iodine Oxidation (IODOX) System. This system serves to remove iodine from the DOG system effluent by absorption into hyperazeotropic nitric acid. 7 refs., 11 figs., 10 tabs

Evaluation of Ruthenium Capture Methods for Tritium Pretreatment Off-Gas Streams

Energy Technology Data Exchange (ETDEWEB)

Spencer, Barry B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jubin, Robert Thomas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bruffey, Stephanie H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Strachan, Denis M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-07-01

In the reprocessing of used nuclear fuel, radioactive elements are released into various plant off-gas streams. While much research and development has focused on the abatement of the volatile nuclides ³H, ¹⁴C, ⁸⁵Kr, and ¹²⁹I, the potential release of semivolatile isotopes that could also report to the off-gas streams in a reprocessing facility has been examined. Ruthenium (as ¹⁰⁶Ru) has been identified as one of the semivolatile nuclides requiring the greatest degree of abatement prior to discharging the plant off-gas to the environment.

Stability for Function Trade-Offs in the Enolase Superfamily 'Catalytic Module'

Energy Technology Data Exchange (ETDEWEB)

Nagatani, R.A.; Gonzalez, A.; Shoichet, B.K.; Brinen, L.S.; Babbitt, P.C.; /UC, San Francisco /SLAC, SSRL

2007-07-12

Enzyme catalysis reflects a dynamic interplay between charged and polar active site residues that facilitate function, stabilize transition states, and maintain overall protein stability. Previous studies show that substituting neutral for charged residues in the active site often significantly stabilizes a protein, suggesting a stability trade-off for functionality. In the enolase superfamily, a set of conserved active site residues (the ''catalytic module'') has repeatedly been used in nature in the evolution of many different enzymes for the performance of unique overall reactions involving a chemically diverse set of substrates. This catalytic module provides a robust solution for catalysis that delivers the common underlying partial reaction that supports all of the different overall chemical reactions of the superfamily. As this module has been so broadly conserved in the evolution of new functions, we sought to investigate the extent to which it follows the stability-function trade-off. Alanine substitutions were made for individual residues, groups of residues, and the entire catalytic module of o-succinylbenzoate synthase (OSBS), a member of the enolase superfamily from Escherichia coli. Of six individual residue substitutions, four (K131A, D161A, E190A, and D213A) substantially increased protein stability (by 0.46-4.23 kcal/mol), broadly consistent with prediction of a stability-activity trade-off. The residue most conserved across the superfamily, E190, is by far the most destabilizing. When the individual substitutions were combined into groups (as they are structurally and functionally organized), nonadditive stability effects emerged, supporting previous observations that residues within the module interact as two functional groups within a larger catalytic system. Thus, whereas the multiple-mutant enzymes D161A/E190A/D213A and K131A/K133A/D161A/E190A/D213A/K235A (termed 3KDED) are stabilized relative to the wild-type enzyme (by 1

Modeling The Impact Of Elevated Mercury In Defense Waste Processing Facility Melter Feed On The Melter Off-Gas System - Preliminary Report

International Nuclear Information System (INIS)

Zamecnik, J.; Choi, A.

2009-01-01

The Defense Waste Processing Facility (DWPF) is currently evaluating an alternative Chemical Process Cell (CPC) flowsheet to increase throughput. It includes removal of the steam-stripping step, which would significantly reduce the CPC processing time and lessen the sampling needs. However, its downside would be to send 100% of the mercury that come in with the sludge straight to the melter. For example, the new mercury content in the Sludge Batch 5 (SB5) melter feed is projected to be 25 times higher than that in the SB4 with nominal steam stripping of mercury. This task was initiated to study the impact of the worst-case scenario of zero-mercury-removal in the CPC on the DWPF melter off-gas system. It is stressed that this study is intended to be scoping in nature, so the results presented in this report are preliminary. In order to study the impact of elevated mercury levels in the feed, it is necessary to be able to predict how mercury would speciate in the melter exhaust under varying melter operating conditions. A homogeneous gas-phase oxidation model of mercury by chloride was developed to do just that. The model contains two critical parameters pertaining to the partitioning of chloride among HCl, Cl, Cl 2 , and chloride salts in the melter vapor space. The values for these parameters were determined at two different melter vapor space temperatures by matching the calculated molar ratio of HgCl (or Hg 2 Cl 2 ) to HgCl 2 with those measured during the Experimental-Scale Ceramic Melter (ESCM) tests run at the Pacific Northwest National Laboratory (PNNL). The calibrated model was then applied to the SB5 simulant used in the earlier flowsheet study with an assumed mercury stripping efficiency of zero; the molar ratio of Cl-to-Hg in the resulting melter feed was only 0.4, compared to 12 for the ESCM feeds. The results of the model run at the indicated melter vapor space temperature of 650 C (TI4085D) showed that due to excessive shortage of chloride, only 6% of

Assessment of Submarine Slope Stability on the Continental Margin off SW Taiwan

Science.gov (United States)

Hsu, Huai-Houh; Dong, Jia-Jyun; Cheng, Win-Bin; Su, Chih-Chieh

2017-04-01

The abundant gas hydrate reservoirs are distributed in the southwest (SW) off Taiwan. To explore this new energy, geological methods were systematically used and mainly emphasized on the storage potential evaluation. On the other hand, the correlation between gas hydrate dissociation and submarine slope stability is also an important issue. In this study, three submarine profiles on the active and passive continental margin were selected and assessed their slope stabilities by considering two influence factors (seismic forces and number of sedimentary layers). The gravity corers obtained from these three sites (Xiaoliuqiu, Yuan-An Ridge, and Pointer Ridge) to conduct soil laboratory tests. The physical property tests and isotropically consolidated undrained (CIU) triaxial tests were carried out to establish reference properties and shear strength parameters. Before the stability analysis is performed, it is also necessary to construct the seabed profile. For each submarine profile, data from P-waves and from S-waves generated by P-S conversion on reflection from airgun shots recorded along one line of ocean bottom seismometers were used to construct 2-D velocity sections. The seabed strata could be simplified to be only one sedimentary layer or to be multilayer in accordance with the velocity structure profile. Results show the safety factors (FS) of stability analysis are obviously different in considering the number of sedimentary layers, especially for a very thin layer of sediments on a steep slope. The simplified strata condition which treated all seabed strata as only one sedimentary layer might result in the FS lower than 1 and the slope was in an unstable state. On the contrary, the FS could be higher than 10 in a multilayer condition.

Nuclei far off the stability line

International Nuclear Information System (INIS)

Fenyes, T.

1978-01-01

Theoretical and experimental aspects of the formation of some ''exotic'' nuclei far off the stability line were reviewed in addition to the relevant results of research in this field. Results in beta- and gamma-ray spectroscopy, heavy-ion-spectroscopy, achievements in the fields of measuring the atomic mass, the moment, and the radius of the nuclei as well as some astronomical aspects were described. (Z.P.)

MEMBRANE SYSTEM FOR RECOVERY OF VOLATILE ORGANIC COMPOUNDS FROM REMEDIATION OFF-GASES

International Nuclear Information System (INIS)

Wijmans, J.G.

2003-01-01

In situ vacuum extraction, air or steam sparging, and vitrification are widely used to remediate soil contaminated with volatile organic compounds (VOCs). All of these processes produce a VOC-laden air stream from which the VOC must be removed before the air can be discharged or recycled to the generating process. Treatment of these off-gases is often a major portion of the cost of the remediation project. Currently, carbon adsorption and catalytic incineration are the most common methods of treating these gas streams. Membrane Technology and Research, Inc. (MTR) proposed an alternative treatment technology based on selective membranes that separate the organic components from the gas stream, producing a VOC-free air stream. This technology can be applied to off-gases produced by various remediation activities and the systems can be skid-mounted and automated for easy transportation and unattended operation. The target performance for the membrane systems is to produce clean air (less than 10 ppmv VOC) for discharge or recycle, dischargeable water (less than 1 ppmw VOC), and a concentrated liquid VOC phase. This report contains the results obtained during Phase II of a two-phase project. In Phase I, laboratory experiments were carried out to demonstrate the feasibility of the proposed approach. In the subsequent Phase II project, a demonstration system was built and operated at the McClellan Air Force Base near Sacramento, California. The membrane system was fed with off-gas from a Soil Vacuum Extraction (SVE) system. The work performed in Phase II demonstrated that the membrane system can reduce the VOC concentration in remediation off-gas to 10 ppmv, while producing a concentrated VOC phase and dischargeable water containing less than 1 ppmw VOC. However, the tests showed that the presence of 1 to 3% carbon dioxide in the SVE off-gas reduced the treatment capacity of the system by a factor of three to four. In an economic analysis, treatment costs of the membrane

Avoiding Carbon Bed Hot Spots in Thermal Process Off-Gas Systems

International Nuclear Information System (INIS)

Soelberg, Nick; Enneking, Joe

2011-01-01

Mercury has had various uses in nuclear fuel reprocessing and other nuclear processes, and so is often present in radioactive and mixed (radioactive and hazardous) wastes. Test programs performed in recent years have shown that mercury in off-gas streams from processes that treat radioactive wastes can be controlled using fixed beds of activated sulfur-impregnated carbon, to levels low enough to comply with air emission regulations such as the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards. Carbon bed hot spots or fires have occurred several times during these tests, and also during a remediation of tanks that contained mixed waste. Hot spots occur when localized areas in a carbon bed become heated to temperatures where oxidation occurs. This heating typically occurs due to heat of absorption of gas species onto the carbon, but it can also be caused through external means such as external heaters used to heat the carbon bed vessel. Hot spots, if not promptly mitigated, can grow into bed fires. Carbon bed hot spots and fires must be avoided in processes that treat radioactive and mixed waste. Hot spots are detected by (a) monitoring in-bed and bed outlet gas temperatures, and (b) more important, monitoring of bed outlet gas CO concentrations. Hot spots are mitigated by (a) designing for appropriate in-bed gas velocity, for avoiding gas flow maldistribution, and for sufficient but not excessive bed depth, (b) appropriate monitoring and control of gas and bed temperatures and compositions, and (c) prompt implementation of corrective actions if bed hot spots are detected. Corrective actions must be implemented quickly if bed hot spots are detected, using a graded approach and sequence starting with corrective actions that are simple, quick, cause the least impact to the process, and are easiest to recover from.

Off-gas filter system of the SNR-300

International Nuclear Information System (INIS)

Boehm, L.; Jordan, S.; Schikarski, W.

1975-01-01

The Reventing-Exventing-System of the German Liquid Metal Fast Breeder Prototype SNR-300 is described. After an accident with major damage to the core the ventilation valves are quickly closed. At the same time the blower of the reventing system evacuates the reventing gap up to a pressure difference of 2 mbar between the containment and the outer atmosphere. This pressure difference prevents a leakage from the containment to the outside. The revented gas is recirculated into the outer-containment. Leaks from the atmosphere and possibly from the inner containment into the reventing gap increase the pressure in the outer-containment. Therefore depending on the pressure build-up which is determined by the course of the accident, it is necessary to exvent the containment after several days. The exvented gas is filtered by a filter combination consisting of pre-filters, charcoal-filters and HEPA-filters. Because accidental sodium fires produce high concentrations of sodium oxide-aerosols this filter system must resist chemical aggressive aerosols. (U.S.)

Off-Gas Adsorption Model Capabilities and Recommendations

Energy Technology Data Exchange (ETDEWEB)

Lyon, Kevin L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Welty, Amy K. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Law, Jack [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ladshaw, Austin [Georgia Inst. of Technology, Atlanta, GA (United States); Yiacoumi, Sotira [Georgia Inst. of Technology, Atlanta, GA (United States); Tsouris, Costas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2016-03-01

Off-gas treatment is required to reduce emissions from aqueous fuel reprocessing. Evaluating the products of innovative gas adsorption research requires increased computational simulation capability to more effectively transition from fundamental research to operational design. Early modeling efforts produced the Off-Gas SeParation and REcoverY (OSPREY) model that, while efficient in terms of computation time, was of limited value for complex systems. However, the computational and programming lessons learned in development of the initial model were used to develop Discontinuous Galerkin OSPREY (DGOSPREY), a more effective model. Initial comparisons between OSPREY and DGOSPREY show that, while OSPREY does reasonably well to capture the initial breakthrough time, it displays far too much numerical dispersion to accurately capture the real shape of the breakthrough curves. DGOSPREY is a much better tool as it utilizes a more stable set of numerical methods. In addition, DGOSPREY has shown the capability to capture complex, multispecies adsorption behavior, while OSPREY currently only works for a single adsorbing species. This capability makes DGOSPREY ultimately a more practical tool for real world simulations involving many different gas species. While DGOSPREY has initially performed very well, there is still need for improvement. The current state of DGOSPREY does not include any micro-scale adsorption kinetics and therefore assumes instantaneous adsorption. This is a major source of error in predicting water vapor breakthrough because the kinetics of that adsorption mechanism is particularly slow. However, this deficiency can be remedied by building kinetic kernels into DGOSPREY. Another source of error in DGOSPREY stems from data gaps in single species, such as Kr and Xe, isotherms. Since isotherm data for each gas is currently available at a single temperature, the model is unable to predict adsorption at temperatures outside of the set of data currently

Separation of krypton from dissolver off-gas of a reprocessing plant using preparative gas chromatography

International Nuclear Information System (INIS)

Matoni, M.

1984-02-01

Kr-85 can be separated from the pre-purified purge air in the final processing step of the purification phase for dissolver off-gases of a reprocessing plant with the aid of preparative gas chromatography. Activated carbon adsorbers in combination with helium as carrier gas permits maximum gas mixture through-flow. A separation temperature of 30 0 C is considered optimal. An adsorbent volume of 40 dm 3 is necessary for processing the residual gas flow of 2.5 Nm 3 /h; the adsorbent is divided between 2 columns linked in series each of which are 2 m long with an internal diameter of 100 mm. The helium flow required is five times greater than the off-gas flow. The degree of purity for krypton is greater than 90% for a decontamination factor of greater than 1000. (orig./HP) [de

Thermoeconomic optimization of a cryogenic refrigeration cycle for re-liquefaction of the LNG boil-off gas

Energy Technology Data Exchange (ETDEWEB)

Sayyaadi, Hoseyn; Babaelahi, M. [Faculty of Mechanical Engineering-Energy Division, K.N. Toosi University of Technology, P.O. Box: 19395-1999, No. 15-19, Pardis Str., Mollasadra Ave., Vanak Sq., Tehran 1999 143344 (Iran)

2010-09-15

The development of the liquefaction process for the Liquefied Natural Gas (LNG) boil-off re-liquefaction plants will be addressed to provide an environmentally friendly and cost effective solution for the gas transportation. In this manner, onboard boil-off gas (BOG) re-liquefaction system as a cryogenic refrigeration cycle is utilized in order to re-liquefy the BOG and returns it to the cargo tanks instead of burning it. In this paper, a thermoeconomic optimization of the LNG-BOG liquefaction system is performed. A thermoeconomic model based on energy and exergy analyses and an economic model according to the total revenue requirement (TRR) are developed. Minimizing of the unit cost of the refrigeration effect as a product of BOG re-liquefaction plant is performed using the genetic algorithm. Results of thermoeconomic optimization are compared with corresponding features of the base case system. Finally, sensitivity of the total cost of the system product with respect to the variation of some operating parameters is studied. (author)

Time resolved mass flow measurements for a fast gas delivery system

International Nuclear Information System (INIS)

Ruden, E.L.; Degnan, J.H.; Hussey, T.W.; Scott, M.C.; Graham, J.D.; Coffey, S.K.

1992-01-01

A technique is demonstrated whereby the delivered mass and flow rate vs. time of a short rise time gas delivery system may be accurately determined. The gas mass M which flows past a point in a gas delivery system by an arbitrary time t may be accurately measured if that point is sealed off within a time interval short compared to the mass flow time scale. If the ejected mass is allowed to equilibrate in a known volume after being cut off from its source, a conventional static pressure measurement before and after injection, and application of the ideal gas law suffices. Assuming reproducibility, a time history M(t) may be generated, allowing the flow rate vs. time dM(t)/dt to be determined. Mass flow measurements are presented for a fast delivery system in which the flow of argon through a 3.2 mm I.D., 0.76 mm thick copper tube is cut off by imploding (θ pinching) the tube using a single turn tungsten magnetic field coil. Pinch discharge parameters are 44 μf, 20 kV, 47 nH, 3.5 mΩ, 584 kA, and 8.63 ps current period. Optical measurements of the tube's internal area vs. time indicate that the tube is sealed 2 ps from the time the tube is still 90% open (7 μs from the start of pinch current). The pinch delay is varied from 500--1,500 ps from the valve trigger (0--1,000 ps from the start of gas flow). The mass injected into the test volume is ∼ 100 μg during this interval. The leak rate of the sealed tube results in a mass increase of only ∼ 0.1 μg by the time the pressure gauge stabilizes (6 s). Results are correlated with piezoelectric probe measurements of the gas flow and 2-D axisymmetric numerical simulations of the θ pinch process. Simulations of a θ pinch suitable for characterizing an annular supersonic nozzle typical of those used in gas puff z pinches are discussed

MODELING THE IMPACT OF ELEVATED MERCURY IN DEFENSE WASTE PROCESSING FACILITY MELTER FEED ON THE MELTER OFF-GAS SYSTEM-PRELIMINARY REPORT

Energy Technology Data Exchange (ETDEWEB)

Zamecnik, J.; Choi, A.

2010-08-18

chloride, only 6% of the mercury fed is expected to get oxidized, mostly as HgCl, while the remaining mercury would exist either as elemental mercury vapor (90%) or HgO (4%). Noting that the measured chloride level in the SB5 qualification sample was an order of magnitude lower than that used in the SB5 simulant, the degree of chloride shortage will be even greater. As a result, the projected level of HgCl in the actual SB5 melter exhaust will be even lower than 6% of the total mercury fed, while that of elemental mercury is likely to be greater than 90%. The homogeneous oxidation of mercury in the off-gas was deemed to be of primary importance based on the postulation that mercury and other volatile salts form submicron sized aerosols upon condensation and thus remain largely in the gas stream downstream of the quencher where they can deposit in the off-gas lines, Steam-Atomized Scrubbers (SAS), and High-Efficiency Mist Eliminator (HEME). Formation of these submicron semi-volatile salts in the condensate liquid is considered to be unlikely, so the liquid phase reactions were considered to be less important. However, subsequent oxidation of mercury in the liquid phase in the off-gas system was examined in a simplified model of the off-gas condensate. It was found that the condensate chemistry was consistent with further oxidation of elemental mercury to Hg{sub 2}Cl{sub 2} and conversion of HgO to chlorides. The results were consistent with the available experimental data. It should also be noted that the model predictions presented in this report do not include any physically entrained solids, which typically account for much of the off-gas carryover on a mass basis. The high elemental mercury vapor content predicted at the DWPF Quencher inlet means that physically entrained solids could provide the necessary surface onto which elemental mercury vapor could condense, thereby coating the solids as well as the internal surfaces of the off-gas system with mercury. Clearly

Power stabilized CO2 gas transport laser

International Nuclear Information System (INIS)

Foster, J.D.; Kirk, R.F.; Moreno, F.E.; Ahmed, S.A.

1975-01-01

The output power of a high power (1 kW or more) CO 2 gas transport laser is stabilized by flowing the gas mixture over copper plated baffles in the gas channel during operation of the laser. Several other metals may be used instead of copper, for example, nickel, manganese, palladium, platinum, silver and gold. The presence of copper in the laser gas circuit stabilizes output power by what is believed to be a compensation of the chemical changes in the gas due to the cracking action of the electrical discharge which has the effect of diminishing the capactiy of the carbon dioxide gas mixture to maintain the rated power output of the laser. (U.S.)

Sorption Modeling and Verification for Off-Gas Treatment

Energy Technology Data Exchange (ETDEWEB)

Tavlarides, Lawrence L. [Syracuse Univ., NY (United States); Lin, Ronghong [Syracuse Univ., NY (United States); Nan, Yue [Syracuse Univ., NY (United States); Yiacoumi, Sotira [Georgia Inst. of Technology, Atlanta, GA (United States); Tsouris, Costas [Georgia Inst. of Technology, Atlanta, GA (United States); Ladshaw, Austin [Georgia Inst. of Technology, Atlanta, GA (United States); Sharma, Ketki [Georgia Inst. of Technology, Atlanta, GA (United States); Gabitto, Jorge [Prairie View A & M Univ., Prairie View, TX (United States); DePaoli, David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2015-04-29

The project has made progress toward developing a comprehensive modeling capability for the capture of target species in off gas evolved during the reprocessing of nuclear fuel. The effort has integrated experimentation, model development, and computer code development for adsorption and absorption processes. For adsorption, a modeling library has been initiated to include (a) equilibrium models for uptake of off-gas components by adsorbents, (b) mass transfer models to describe mass transfer to a particle, diffusion through the pores of the particle and adsorption on the active sites of the particle, and (c) interconnection of these models to fixed bed adsorption modeling which includes advection through the bed. For single-component equilibria, a Generalized Statistical Thermodynamic Adsorption (GSTA) code was developed to represent experimental data from a broad range of isotherm types; this is equivalent to a Langmuir isotherm in the two-parameter case, and was demonstrated for Kr on INL-engineered sorbent HZ PAN, water sorption on molecular sieve A sorbent material (MS3A), and Kr and Xe capture on metal-organic framework (MOF) materials. The GSTA isotherm was extended to multicomponent systems through application of a modified spreading pressure surface activity model and generalized predictive adsorbed solution theory; the result is the capability to estimate multicomponent adsorption equilibria from single-component isotherms. This advance, which enhances the capability to simulate systems related to off-gas treatment, has been demonstrated for a range of real-gas systems in the literature and is ready for testing with data currently being collected for multicomponent systems of interest, including iodine and water on MS3A. A diffusion kinetic model for sorbent pellets involving pore and surface diffusion as well as external mass transfer has been established, and a methodology was developed for determining unknown diffusivity parameters from transient

Sorption Modeling and Verification for Off-Gas Treatment

International Nuclear Information System (INIS)

Tavlarides, Lawrence L.; Lin, Ronghong; Nan, Yue; Yiacoumi, Sotira; Tsouris, Costas; Ladshaw, Austin; Sharma, Ketki; Gabitto, Jorge; DePaoli, David

2015-01-01

The project has made progress toward developing a comprehensive modeling capability for the capture of target species in off gas evolved during the reprocessing of nuclear fuel. The effort has integrated experimentation, model development, and computer code development for adsorption and absorption processes. For adsorption, a modeling library has been initiated to include (a) equilibrium models for uptake of off-gas components by adsorbents, (b) mass transfer models to describe mass transfer to a particle, diffusion through the pores of the particle and adsorption on the active sites of the particle, and (c) interconnection of these models to fixed bed adsorption modeling which includes advection through the bed. For single-component equilibria, a Generalized Statistical Thermodynamic Adsorption (GSTA) code was developed to represent experimental data from a broad range of isotherm types; this is equivalent to a Langmuir isotherm in the two-parameter case, and was demonstrated for Kr on INL-engineered sorbent HZ PAN, water sorption on molecular sieve A sorbent material (MS3A), and Kr and Xe capture on metal-organic framework (MOF) materials. The GSTA isotherm was extended to multicomponent systems through application of a modified spreading pressure surface activity model and generalized predictive adsorbed solution theory; the result is the capability to estimate multicomponent adsorption equilibria from single-component isotherms. This advance, which enhances the capability to simulate systems related to off-gas treatment, has been demonstrated for a range of real-gas systems in the literature and is ready for testing with data currently being collected for multicomponent systems of interest, including iodine and water on MS3A. A diffusion kinetic model for sorbent pellets involving pore and surface diffusion as well as external mass transfer has been established, and a methodology was developed for determining unknown diffusivity parameters from transient

Process for off-gas particulate removal and apparatus therefor

International Nuclear Information System (INIS)

Carl, D.E.

1997-01-01

In the event of a breach in the off-gas line of a melter operation requiring closure of the line, a secondary vessel vent line is provided with a particulate collector utilizing atomization for removal of large particulates from the off-gas. The collector receives the gas containing particulates and directs a portion of the gas through outer and inner annular channels. The collector further receives a fluid, such as water, which is directed through the outer channel together with a second portion of the particulate-laden gas. The outer and inner channels have respective ring-like termination apertures concentrically disposed adjacent one another on the outer edge of the downstream side of the particulate collector. Each of the outer and inner channels curves outwardly away from the collector's centerline in proceeding toward the downstream side of the collector. Gas flow in the outer channel maintains the fluid on the channel's wall in the form of a ''wavy film,'' while the gas stream from the inner channel shears the fluid film as it exits the outer channel in reducing the fluid to small droplets. Droplets formed by the collector capture particulates in the gas stream by one of three mechanisms: impaction, interception or Brownian diffusion in removing the particulates. The particulate-laden droplets are removed from the fluid stream by a vessel vent condenser or mist eliminator. 4 figs

Relativistic stability of interacting Fermi gas in a strong magnetic field

International Nuclear Information System (INIS)

Wang Lilin; Tian Jincheng; Men Fudian; Zhang Yipeng

2013-01-01

By means of the single particle energy spectrum of weak interaction between fermions and Poisson formula, the thermodynamic potential function of relativistic Fermi gas in a strong magnetic field is derived. Based on this, we obtained the criterion of stability for the system. The results show that the mechanics stability of a Fermi gas with weak interacting is influenced by the interacting. While the magnetic field is able to regulate the influence and the relativistic effect has almost no effect on it. (authors)

Adaptability and stability of soybean genotypes in off-season cultivation.

Science.gov (United States)

Batista, R O; Hamawaki, R L; Sousa, L B; Nogueira, A P O; Hamawaki, O T

2015-08-14

The oil and protein contents of soybean grains are important quantitative traits for use in breeding. However, few breeding programs perform selection based on these traits in different environments. This study assessed the adaptability and stability of 14 elite early soybean breeding lines in off-season cultivation with respect to yield, and oil and protein contents. A range of statistical methods was applied and these analyses indicated that for off-season cultivation, the lines UFUS 5 and UFUS 10 could be recommended due to their superior performance in grain yield, oil content, and specific adaptability to unfavorable environments along with high stability in these characteristics. Also recommended were UFUS 06, which demonstrated superior performance in all three tested characteristics and showed adaptation to favorable environments, and UFUS 13, which showed high adaptability and stability and a superior performance for protein content.

Investigations of Slip Effect on the Performance of Micro Gas Bearings and Stability of Micro Rotor-Bearing Systems

Directory of Open Access Journals (Sweden)

Jieyu Chen

2007-08-01

Full Text Available Incorporating the velocity slip effect of the gas flow at the solid boundary, theperformance and dynamic response of a micro gas-bearing-rotor system are investigated inthis paper. For the characteristic length scale of the micro gas bearing, the gas flow in thebearing resides in the slip regime rather than in the continuum regime. The modifiedReynolds equations of different slip models are presented. Gas pressure distribution and loadcarrying capacity are obtained by solving the Reynolds equations with finite differentmethod (FDM. Comparing results from different models, it is found that the second orderslip model agrees reasonably well with the benchmarked solutions obtained from thelinearized Boltzmann equation. Therefore, dynamic coefficients derived from the secondorder slip model are employed to evaluate the linear dynamic stability and vibrationcharacteristics of the system. Compared with the continuum flow model, the slip effectreduces dynamic coefficients of the micro gas bearing, and the threshold speed for stableoperation is consequently raised. Also, dynamic analysis shows that the system responseschange with variation of the operating parameters including the eccentricity ratio, therotational speed, and the unbalance ratio.

Evaluation of the HEPA filter in-place test method in a corrosive off-gas environment

International Nuclear Information System (INIS)

Murphy, L.P.; Wong, M.A.; Girton, R.C.

1978-01-01

Experiments were performed to determine if the combined effects of temperature, humidity, and oxides of nitrogen (NO/sub x/) hinder the in-place testing of high-efficiency particulate air (HEPA) filters used for cleaning the off-gas from a nuclear waste solidification facility. The laboratory system that was designed to simulate the process off-gas contained two HEPA filters in series with sample ports before each filter and after the filter bank. The system also included a reaction bomb for partial conversion of NO to NO 2 . Instrumentation measured stream flow, humidity, NO/sub x/ concentration, and temperature. Comparison measurements of the DOP concentrations were made by a forward light-scattering photometer and a single particle intra-cavity laser particle spectrometer. Experimental conditions could be varied, but maximum system capabilities were 95% relative humidity, 90 0 C, and 10,000 ppM of NO/sub x/. A 2 3 factorial experimental design was used for the test program. This design determined the main effects of each factor plus the interactions of the factors in combination. The results indicated that water vapor and NO/sub x/ interfere with the conventional photometer measurements. Suggested modifications that include a unique sample dryer are described to correct the interferences. The laser particle spectrometer appears to be an acceptable instrument for measurements under adverse off-gas conditions

Membrane System for the Recovery of Volatile Organic Compounds from Remediation Off-Gases. Innovative Technology Summary Report

International Nuclear Information System (INIS)

2001-01-01

Membrane Technology and Research, Inc.'s (MTR's) membrane-based off-gas treatment technology separates the organic components from the off-gas stream, producing a VOC-free air stream that can be discharged or recycled to the gas-generating process. The membrane system produces a constant, high-quality air discharge stream irrespective of the feed-air composition. The system also produces a concentrated liquid VOC stream for disposal. Any water vapor present in the off-gas is removed as condensed dischargeable water. Benefits: Applicable to a broad range of off-gas generating sources. Target streams are off-gas from soil remediation by in situ vacuum extraction or air and steam sparging, and soil vitrification Suitable for remote sites: systems require minimal site preparation, little operator attention once installed, electrical power but no other utilities, and no expendable chemicals Minimizes waste volume: dischargeable air and water are produced, and VOCs removed from the feed gas ar e concentrated into a condensed liquid. No other waste streams result Treats off-gases containing both flammable and nonflammable and chlorinated and nonchlorinated VOCs Cost competitive with other technologies in the VOC concentration range 100-1,000 ppm and offers significant cost reduction at higher VOC concentrations Systems are easily moved and transported to new sites with a minimum of refurbishing or modification Generates no air emissions, minimizing permitting issues and speeding up the start of a clean-up operation Technology: Removal of VOCs from air streams with membranes is a relatively new technology

Waste Isolation Pilot Plant: Alcove Gas Barrier trade-off study

International Nuclear Information System (INIS)

Lin, M.S.; Van Sambeek, L.L.

1992-07-01

A modified Kepner-Tregoe method was used for a trade-off study of Alcove Gas Barrier (AGB) concepts for the Waste Isolation Pilot Plant. The AGB is a gas-constraining seal to be constructed in an alcove entrance drift. In this trade-off study, evaluation criteria were first selected. Then these criteria were classified as to their importance to the task, assigning a weighting value to each aspect. Eleven conceptual design alternatives were developed based on geometrical/geological considerations, construction materials, constructibility, and other relevant factors and evaluated

Radioactive gas waste processing device

International Nuclear Information System (INIS)

Soma, Koichi.

1996-01-01

The present invention concerns a radioactive gas waste processing device which extracts exhaust gases from a turbine condensator in a BWR type reactor and releases them after decaying radioactivity thereof during temporary storage. The turbine condensator is connected with an extracting ejector, a preheater, a recombiner for converting hydrogen gas into steams, an off gas condensator for removing water content, a flow rate control valve, a dehumidifier, a hold up device for removing radiation contaminated materials, a vacuum pump for sucking radiation decayed-off gases, a circulation water tank for final purification and an exhaustion cylinder by way of connection pipelines in this order. An exhaust gas circulation pipeline is disposed to circulate exhaust gases from an exhaust gas exit pipeline of the recycling water tank to an exhaust gas exit pipeline of the exhaust gas condensator, and a pressure control valve is disposed to the exhaust gas circulation pipeline. This enable to perform a system test for the dehumidification device under a test condition approximate to the load of the dehumidification device under actual operation state, and stabilize both of system flow rate and pressure. (T.M.)

Effect of changes in seafloor temperature and sea-level on gas hydrate stability

Energy Technology Data Exchange (ETDEWEB)

Garg, S.K.; Pritchett, W. [Science Applications International Corp., San Diego, CA (United States)

2008-07-01

Natural gas hydrates occur in oceanic sediments and in permafrost regions around the world. As a greenhouse gas, large amounts of methane released from the global hydrate reservoir would have a significant impact on Earth's climate. The role of methane released by hydrate dissociation in climate change is uncertain. However, changes in global climate such as glaciation and warming can destabilize the hydrates. During the last glacial maximum, the sea level dropped about 100 meters. It has been suggested that the sea-level fall was associated with gas hydrate instability and seafloor slumping. This paper investigated the effect of changes in seafloor temperature and sea level on gas hydrate stability and on gas venting at the seafloor. A one-dimensional numerical computer model (simulator) was developed to describe methane hydrate formation, decomposition, reformation, and distribution with depth below the seafloor in the marine environment. The simulator was utilized to model hydrate distributions at two sites, notably Blake Ridge, located offshore South Carolina and Hydrate Ridge, located off the coast of Oregon. The numerical models for the two sites were conditioned by matching the sulfate, chlorinity, and hydrate distribution measurements. The effect of changes in seafloor temperature and sea-level on gas hydrate stability were then investigated. It was concluded that for Blake Ridge, changes in hydrate concentration were small. Both the changes in seafloor temperature and sea-level led to a substantial increase in gas venting at the seafloor for Hydrate Ridge. 17 refs., 8 figs.

Formation of the ZnFe2O4 phase in an electric arc furnace off-gas treatment system.

Science.gov (United States)

Suetens, T; Guo, M; Van Acker, K; Blanpain, B

2015-04-28

To better understand the phenomena of ZnFe2O4 spinel formation in electric arc furnace dust, the dust was characterized with particle size analysis, X-ray fluorescence (XRF), electron backscatter diffraction (EBSD), and electron probe micro-analysis (EPMA). Different ZnFe2O4 formation reaction extents were observed for iron oxide particles with different particle sizes. ZnO particles were present as both individual particles and aggregated on the surface of larger particles. Also, the slag particles found in the off-gas were shown not to react with the zinc vapor. After confirming the presence of a ZnFe2O4 formation reaction, the thermodynamic feasibility of in-process separation - a new electric arc furnace dust treatment technology - was reevaluated. The large air intake and the presence of iron oxide particles in the off-gas were included into the thermodynamic calculations. The formation of the stable ZnFe2O4 spinel phase was shown to be thermodynamically favorable in current electric arc furnace off-gas ducts conditions even before reaching the post combustion chamber. Copyright © 2015 Elsevier B.V. All rights reserved.

Compressed gas fuel storage system

Science.gov (United States)

Wozniak, John J.; Tiller, Dale B.; Wienhold, Paul D.; Hildebrand, Richard J.

2001-01-01

A compressed gas vehicle fuel storage system comprised of a plurality of compressed gas pressure cells supported by shock-absorbing foam positioned within a shape-conforming container. The container is dimensioned relative to the compressed gas pressure cells whereby a radial air gap surrounds each compressed gas pressure cell. The radial air gap allows pressure-induced expansion of the pressure cells without resulting in the application of pressure to adjacent pressure cells or physical pressure to the container. The pressure cells are interconnected by a gas control assembly including a thermally activated pressure relief device, a manual safety shut-off valve, and means for connecting the fuel storage system to a vehicle power source and a refueling adapter. The gas control assembly is enclosed by a protective cover attached to the container. The system is attached to the vehicle with straps to enable the chassis to deform as intended in a high-speed collision.

Development of filters for exhaust air or off-gas cleaning

International Nuclear Information System (INIS)

Wilhelm, J.

1988-01-01

The activities of the 'Laboratorium fuer Aerosolphysik und Filtertechnik II' of the 'Kernforschungszentrum Karlsruhe' concentrate on the development of filters to be used for cleaning nuclear and conventional exhaust air and off-gas. Originally, these techniques were intended to be applied in nuclear facilities only. Their application for conventional gas purification, however, has led to a reorientation of research and development projects. By way of example, it is reported about the use of the multi-way sorption filter for radioiodine removal in nuclear power plants and following flue-gas purification in heating power plants as well as for off-gas cleaning in chemical industry. The improvement of HEPA filters and the development of metal fibre filters has led to components which can be used in the range of high humidity and moisture as well as at high temperatures and an increased differential pressure. The experience obtained in the field of high-efficiency filtering of nuclear airborne particles is made use of during the investigations concerning the removal of particles of conventional pollutants in the submicron range. A technique of radioiodine removal and an improved removal of airborne particles has been developed for use in the future reprocessing plant. Thus, a maximum removal efficiency can be achieved and an optimum waste management is made possible. It is reported about the components obtained as a result of these activities and their use for off-gas cleaning in the Wackersdorf reprocessing plant (WAW). (orig.) [de

Aerosol and iodine removal system for the dissolver off-gas in a large fuel reprocessing plant

International Nuclear Information System (INIS)

Furrer, J.; Wilhelm, J.G.; Jannakos, K.

1979-01-01

A newly developed filter combination for the dissolver off-gas in a reprocessing plant with a throughput of 1400 t/y of heavy metal is presented and single filter components are described. The design principle chosen provides for remote handling and direct disposal in waste drums of 200 l volume. The optimization of housings and filter units is studied on true scale components in the simulated dissolver off-gas of a test facility named PASSAT. This facility will be described. PASSAT will be also used for final testing of the SORPTEX process which is under development. Its concept is included in the paper. The design and function of the new multiway sorption filter providing for complete loading of the iodine sorption material and maintaining continuously high decontamznation factors will also be given. Removal efficiencies measured for aerosols and iodine in an existing reprocessing plant are indicated

Continuous chemical cold traps for reprocessing off-gas purification

International Nuclear Information System (INIS)

Henrich, E.; Bauder, U.; Steinhardt, H.J.; Bumiller, W.

1985-01-01

Absorption of nitrogen oxides and iodine from simulated reprocessing plant off-gas streams has been studied using nitric acid and nitric acid/hydrogen peroxide mixtures at low temperatures. The experiments were carried out at the laboratory and on the engineering scale. The pilot plant scale column has 0.8 m diameter and 16 absorption plates at 0.2 m spacing. Cooling coils on the plates allow operating temperatures down to -60 0 C. The NO concentration in the feed gas usually has been 1% by volume and the flow rate 4-32 m 3 (STP) per hour. The iodine behavior has been studied using I-123 tracer. Results of the study are presented. The chemistry of the processes and the advantages and disadvantages in correlation to the various applications for an off-gas purification in a reprocessing plant are compared and discussed. The processes are compatible with the PUREX process and do not produce additional waste

Gas detection system

International Nuclear Information System (INIS)

Allan, C.J.; Bayly, J.G.

1975-01-01

The gas detection system provides for the effective detection of gas leaks over a large area. It includes a laser which has a laser line corresponding to an absorption line of the gas to be detected. A He-Xe laser scans a number of retroreflectors which are strategically located around a D 2 O plant to detect H 2 S leaks. The reflected beam is focused by a telescope, filtered, and passed into an infrared detector. The laser may be made to emit two frequencies, one of which corresponds with an H 2 S absorption line; or it may be modulated on and off the H 2 S absorption line. The relative amplitude of the absorbed light will be a measure of the H 2 S present

Airborne waste management technology applicable for use in reprocessing plants for control of iodine and other off-gas constituents

International Nuclear Information System (INIS)

Jubin, R.T.

1988-02-01

Extensive work in the area of iodine removal from reprocessing plant off-gas streams using various types of solid sorbent materials has been conducted worldwide over the past two decades. This work has focused on the use of carbon filters, primarily for power plant applications. More recently, the use of silver-containing sorbents has been the subject of considerable research. The most recent work in the United States has addressed the use of silver-exchanged faujasites and mordenites. The chemical reactions of iodine with silver on the sorbent are not well defined, but it is generally believed that chemisorbed iodides and iodates are formed. The process for iodine recovery generally involves passage of the iodine-laden gas stream through a packed bed of the adsorbent material preheated to a temperature of about 150/degree/C. Most iodine removal system designs utilizing silver-containing solid sorbents assume only a 30 to 50% silver utilization. Based on laboratory tests, potentially 60 to 70% of the silver contained in the sorbents can be reacted with iodine. To overcome the high cost of silver associated with these materials, various approaches have been explored. Among these are the regeneration of the silver-containing sorbent by stripping the iodine and trapping the iodine on a sorbent that has undergone only partial silver exchange and is capable of attaining a much higher silver utilization. This summary report describes the US work in regeneration of iodine-loaded solid sorbent material. In addition, the report discusses the broader subject of plant off-gas treatment including system design. The off-gas technologies to recovery No/sub x/ and to recover and dispose of Kr, 14 C, and I are described as to their impacts on the design of an integrated off-gas system. The effect of ventilation philosophy for the reprocessing plant is discussed as an integral part of the overall treatment philosophy of the plant off-gas. 103 refs., 5 figs., 8 tabs

A plasma process controlled emissions off-gas demonstration

International Nuclear Information System (INIS)

Battleson, D.; Kujawa, S.T.; Leatherman, G.

1995-01-01

Thermal technologies are currently identified as playing an important role in the treatment of many DOE waste streams, and emissions from these processes will be scrutinized by the public, regulators, and stakeholders. For some time, there has been a hesitancy by the public to accept thermal treatment of radioactive contaminated waste because of the emissions from these processes. While the technology for treatment of emissions from these processes is well established, it is not possible to provide the public complete assurance that the system will be in compliance with air quality regulations 100% of the operating time in relation to allowing noncompliant emissions to exit the system. Because of the possibility of noncompliant emissions and the public's concern over thermal treatment systems, it has been decided that the concept of a completely controlled emissions off-gas system should be developed and implemented on Department of Energy (DOE) thermal treatment systems. While the law of conservation of mass precludes a completely closed cycle system, it is possible to apply the complete control concept to emissions

Development of the krypton absorption in liquid carbon dioxide (KALC) process for HTGR off-gas reprocessing

International Nuclear Information System (INIS)

Glass, R.W.; Beaujean, H.W.R.; Cochran, H.D. Jr.; Haas, P.A.; Levins, D.M.; Woods, W.M.

1975-01-01

Reprocessing of High-Temperature Gas-Cooled Reactor (HTGR) fuel involves burning of the graphite-matrix elements to release the fuel for recovery purposes. The resulting off-gas is primarily CO 2 with residual amounts of N 2 , O 2 , and CO, together with fission products. Trace quantities of krypton-85 must be recovered in a concentrated form from the gas stream, but processes commonly employed for rare gas removal and concentration are not suitable for use with off-gas from graphite burning. The KALC (Krypton Absorption in Liquid CO 2 ) process employs liquid CO 2 as a volatile solvent for the krypton and is, therefore, uniquely suited to the task. Engineering development of the KALC process is currently under way at the Oak Ridge National Laboratory (ORNL) and the Oak Ridge Gaseous Diffusion Plant (ORGDP). The ORNL system is designed for close study of the individual separation operations involved in the KALC process, while the ORGDP system provides a complete pilot facility for demonstrating combined operations on a somewhat larger scale. Packed column performance and process control procedures have been of prime importance in the initial studies. Computer programs have been prepared to analyze and model operational performance of the KALC studies, and special sampling and in-line monitoring systems have been developed for use in the experimental facilities. (U.S.)

Dual liquid and gas chromatograph system

Science.gov (United States)

Gay, D.D.

A chromatographic system is described that utilizes one detection system for gas chromatographic and micro-liquid chromatographic determinations. The detection system is a direct-current, atmospheric-pressure, helium plasma emission spectrometer. The detector utilizes a nontransparent plasma source unit which contains the plasma region and two side-arms which receive effluents from the micro-liquid chromatograph and the gas chromatograph. The dual nature of this chromatographic system offers: (1) extreme flexibility in the samples to be examined; (2) extreme low sensitivity; (3) element selectivity; (4) long-term stability; (5) direct correlation of data from the liquid and gas samples; (6) simpler operation than with individual liquid and gas chromatographs, each with different detection systems; and (7) cheaper than a commercial liquid chromatograph and a gas chromatograph.

The blow-off mechanism of a bluff-body stabilized laminar premixed flame

KAUST Repository

Kedia, Kushal S.

2015-04-01

© 2014 The Combustion Institute. The objective of this work is to investigate the dynamics leading to blow-off of a laminar premixed flame stabilized on a confined bluff-body using high fidelity numerical simulations. We used unsteady, fully resolved, two-dimensional simulations with detailed chemical kinetics and species transport for methane-air combustion. The flame-wall interaction between the hot reactants and the heat conducting bluff-body was accurately captured by incorporating the conjugate heat exchange between them. Simulations showed a shear-layer stabilized flame just downstream of the bluff-body, with a recirculation zone formed by the products of combustion. The flame was negatively stretched along its entire length, primarily dominated by the normal component of the strain. Blow-off was approached by decreasing the mixture equivalence ratio, at a fixed Reynolds number, of the incoming flow. A flame is stable (does not undergo blow-off) when (1) flame displacement speed is equal to the flow speed and (2) the gradient of the flame displacement speed normal to its surface is higher than the gradient of the flow speed along the same direction. As the equivalence ratio is reduced, the difference between the former and the latter shrinks until the dynamic stability condition (2) is violated, leading to blow-off. Blow-off initiates at a location where this is first violated along the flame. Our results showed that this location was far downstream from the flame anchoring zone, near the end of the recirculation zone. Blow-off started by flame pinching separating the flame into an upstream moving (carried within the recirculation zone) and a downstream convecting (detached from the recirculation zone) flame piece. Within the range of operating conditions investigated, the conjugate heat exchange with the bluff-body had no impact on the flame blow-off.

On the stability of localized drift modes in the boundary layers of high density gas insulated plasmas

International Nuclear Information System (INIS)

Ohlsson, D.

1977-11-01

Gas blanket systems are of interest for mainly two reasons. First, plasma wall interaction effects are expected to be considerably reduced due to the presence of the surrounding neutral gas. Consequently the impurity radiation due to impurities originating from plasma wall interaction processes is probably eliminated to a large extent. Second, the fueling of a future thermonuclear reactor can take place in a natural way in gas blanket systems in the sense that neutrals can diffuse inwards at a suitable rate to replace burnt fuel under certain conditions. In this analysis we consider certain stability aspects of plasmas surrounded by neutral gas. In particular we consider the stability of localized collisional drift modes, in the cool partially ionized boundary regions. In these regions large pressure gradients are expected due to plasma neutral gas interaction effects. It is concluded that stability is possible within certain parameter ranges due to the presence of several stabilizing effects associated with finite Larmor radius and viscosity effects and coupling between dissipative effects directly or indirectly connected with plasma neutral gas interaction processes

Carbon dioxide-krypton separation and radon removal from nuclear-fuel-reprocessing off-gas streams

International Nuclear Information System (INIS)

Hirsch, P.M.; Higuchi, K.Y.; Abraham, L.

1982-07-01

General Atomic Company (GA) is conducting pilot-plant-scale tests that simulate the treatment of radioactive and other noxious volatile and gaseous constituents of off-gas streams from nuclear reprocessing plants. This paper reports the results of engineering-scale tests performed on the CO 2 /krypton separation and radon holdup/decay subsystems of the GA integrated off-gas treatment system. Separation of CO 2 from krypton-containing gas streams is necessary to facilitate subsequent waste processing and krypton storage. Molecular sieve 5A achieved this separation in dissolver off-gas streams containing relatively low krypton and CO 2 concentrations and in krypton-rich product streams from processes such as the krypton absorption in liquid carbon dioxide (KALC) process. The CO 2 /krypton separation unit is a 30.5-cm-diameter x 1.8-m-long column containing molecular sieve 5A. The loading capacity for CO 2 was determined for gas mixtures containing 250 ppM to 2.2% CO 2 and 170 to 750 ppM krypton in either N 2 or air. Gas streams rich in CO 2 were diluted with N 2 to reduce the temperature rise from the heat of adsorption, which would otherwise affect loading capacity. The effluent CO 2 concentration prior to breakthrough was less than 10 ppM, and the adsorption capacity for krypton was negligible. Krypton was monitored on-line with a time-of-flight mass spectrometer and its concentration determined quantitatively by a method of continuous analysis, i.e., selected-ion monitoring. Radon-220 was treated by holdup and decay on a column of synthetic H-mordenite. The Rn-220 concentration was monitored on-line with flow-through diffused-junction alpha detectors. Single-channel analyzers were utilized to isolate the 6.287-MeV alpha energy band characteristic of Rn-220 decay from energy bands due to daughter products

Treatment of off-gas from lagoon sludge thermal decomposition

International Nuclear Information System (INIS)

Hwang, D. S.; Oh, J. H.; Choi, Y. D.; Hwang, S. T.; Park, J. H.; Ga, M. J.

2005-01-01

Korea Atomic Energy Research Institute (KAERI) has launched a decommissioning program of the uranium conversion plant in 2001. The treatment of the sludge waste, which was generated during the operation of the plant and stored in the lagoon, is one of the most important tasks in the decommissioning program of the plant. The major compounds of the lagoon sludge are ammonium nitrate, sodium nitrate, calcium nitrate, calcium carbonate, and uranium compounds. The minor compounds are iron, magnesium, aluminum, silicon and phosphorus. A treatment process of the sludge was developed as figure 1 based on the results of the sludge characteristics and the developed treatment technologies. A treatment of off-gas evolved from the nitrate salts thermal decomposition is one of the important process. Off-gas treatment by using a selective catalytic reduction (SCR) method was investigated in this study

I-129, Kr-85, C-14 and NO/sub x/ removal from spent fuel dissolver off-gas at atmospheric pressure and at reduced off-gas flow

International Nuclear Information System (INIS)

Henrich, E.; Huefner, R.

1981-01-01

A dissolver off-gas (DOG) system suitable for a LWR, FBR or HTR spent fuel reprocessing plant is described, incorporating the following features: (1) the DOG flow is reduced to a reasonably small volume, using fumeless dissolution conditions, by maintaining high concentrations, the retention procedures are simplified and accompanied by an economic reduction of the equipment size; (2) all process operations are conducted at atmospheric or subatmospheric pressure, including noble gas removal by selective absorption, without using high temperature processes; (3) all processes, except HEPA filtering, are continuous and do not accumulate large amounts of waste nuclides, the DOG process sequence is mutually compatible with itself and with processing in the headend, showing on-line redundancy for the removal of the most radiotoxic nuclides; and (4) the DOG system only deviates slightly from proven technology. The stage of development and relevant results are given both for a lab. scale and a pilot plant scale

Method of treatment in a system passing radioactive material

Energy Technology Data Exchange (ETDEWEB)

Kamiya, K; Kinoshita, M; Asakura, Y

1976-05-14

A method to ensure the safety of the reactor and reduce radiation exposure dose by preventing oxygen hydrogen reaction of the reactor off-gas and accumulation of the radioactive material is described. Substances which are accumulated in an off-gas duct and are likely to capture radioactive material (for instance Pd catalyst falling from a recombiner) is changed into a stable material (for instance, PdI/sub 2/) which is hot likely to capture radioactive material through reaction with a stabilizer (for instance, I/sub 2/, Cl/sub 2/, HCl, etc.). This stabilized material is washed off the atomic power plant system.

Treatment of off-gas evolved from thermal decomposition of sludge waste

International Nuclear Information System (INIS)

Doo-Seong Hwang; Yun-Dong Choi; Gyeong-Hwan Jeong; Jei-Kwon Moon

2013-01-01

Korea Atomic Energy Research Institute (KAERI) started a decommissioning program of a uranium conversion plant. The treatment of the sludge waste, which was generated during the operation of the plant, is one of the most important tasks in the decommissioning program of the plant. The major compounds of sludge waste are nitrate salts and uranium. The sludge waste is denitrated by thermal decomposition. The treatment of off-gas evolved from the thermal decomposition of nitrate salts in the sludge waste is investigated. The nitrate salts in the sludge were decomposed in two steps: the first decomposition is due to the ammonium nitrate, and the second is due to the sodium and calcium nitrate and calcium carbonate. The components of off-gas from the decomposition of ammonium nitrate at low temperature are NH 3 , N 2 O, NO 2 , and NO. In addition, the components from the decomposition of sodium and calcium nitrate at high temperature are NO 2 and NO. Off-gas from the thermal decomposition is treated by the catalytic oxidation of ammonia and selective catalytic reduction (SCR). Ammonia is converted into nitrogen oxides through the oxidation catalyst and all nitrogen oxides are removed by SCR treatment besides nitrous oxide, which is greenhouse gas. An additional process is needed to remove nitrous oxide, and the feeding rate of ammonia in SCR should be controlled properly for evolved nitrogen oxides. (author)

Vanadium redox flow batteries to reach greenhouse gas emissions targets in an off-grid configuration

International Nuclear Information System (INIS)

Arbabzadeh, Maryam; Johnson, Jeremiah X.; De Kleine, Robert; Keoleian, Gregory A.

2015-01-01

Highlights: • We assess energy storage role in reaching emissions targets in an off-grid model. • The energy storage technology is vanadium redox flow battery (VRFB). • We evaluate life cycle GHG emissions and total cost of delivered electricity. • Generation mixes are optimized to meet emissions targets at the minimum cost. • For this model, integrating VRFB is economical to reach very low emissions targets. - Abstract: Energy storage may serve as a solution to the integration challenges of high penetrations of wind, helping to reduce curtailment, provide system balancing services, and reduce emissions. This study determines the minimum cost configuration of vanadium redox flow batteries (VRFB), wind turbines, and natural gas reciprocating engines in an off-grid model. A life cycle assessment (LCA) model is developed to determine the system configuration needed to achieve a variety of CO 2 -eq emissions targets. The relationship between total system costs and life cycle emissions are used to optimize the generation mixes to achieve emissions targets at the least cost and determine when VRFBs are preferable over wind curtailment. Different greenhouse gas (GHG) emissions targets are defined for the off-grid system and the minimum cost resource configuration is determined to meet those targets. This approach determines when the use of VRFBs is more cost effective than wind curtailment in reaching GHG emissions targets. The research demonstrates that while incorporating energy storage consistently reduces life cycle carbon emissions, it is not cost effective to reduce curtailment except under very low emission targets (190 g of CO2-eq/kW h and less for the examined system). This suggests that “overbuilding” wind is a more viable option to reduce life cycle emissions for all but the most ambitious carbon mitigation targets. The findings show that adding VRFB as energy storage could be economically preferable only when wind curtailment exceeds 66% for the

Micro-gas turbine performance optimization by off-design characteristics prediction

Energy Technology Data Exchange (ETDEWEB)

Asgari, M.B.; Pahlevanzadeh, H. [Power and Water University of Technology, Tehran (Iran, Islamic Republic of). Dept. of Mechanical Engineering

2005-07-01

Micro-gas turbines are increasingly seen as a good option for supplying distributed electric or combined heat and power (CHP) systems. Micro turbines operate on the same thermodynamic cycle as the Brayton cycle. Fresh air enters a compressor and air pressure increases isentropically and high-pressure air and fuel are mixed and burnt in the combustion chamber at constant pressure. During this process the flue gas expands to lower pressure and increase volume isentropically. In this study a model was developed using parameters obtained from the compressor and turbine. Ambient temperature and and pressure effects on micro-gas turbines were examined. Customer requirements were used as constraints on micro-gas turbine parameters. The computer software Matlab was used to study the effect of the surge margin on the behaviour of the engine. Optimum performance speeds were presented, and a marginal envelope was obtained at the optimal speed. Issues concerning fuel consumption, power output, and efficiency were considered. The principal results of the simulation presented an optimum region of operation rather than any single optimal point. It was suggested that further research is needed to study the influence of the heat exchanger on efficiency and development of a model of the power electronics so that the complete system can be simulated from power generation. It was noted that although operation of microturbines at high speeds of revolution causes more net power output, this affects the thermal efficiency of the system and fuel consumption is high. It was concluded that optimum operating conditions should be evaluated by satisfying the trade off between net power generated and fuel consumption, as well as the achievable efficiency. 8 refs., 12 figs.

Multi-level computational chemistry study on hydrogen recombination catalyst of off-gas treatment system

International Nuclear Information System (INIS)

Hatakeyama, Nozomu; Ise, Mariko; Inaba, Kenji

2011-01-01

In order to reveal the deactivation mechanism of the hydrogen recombination catalyst of off-gas treatment system, we investigate by using multi-level computational chemistry simulation methods. The recombiner apparatus is modeled by the numerical mesh system in the axial coordinates, and unsteady, advection and reaction rate equations are solved by using a finite difference method. The chemical reactions are formulated to represent adsorption-desorption of hydrogen and oxygen on Pt catalyst, and time developments of the coverage factors of Pt are solved numerically. The computational simulations successfully reproduce the very similar behaviors observed by experiments, such as increasing of the inversion rates of H 2 to H 2 O, the temperatures distributions along the flow direction, dependencies of experimental condition, and so on. Thus Pt poisoning is considered to cause the deactivation of the hydrogen recombination catalyst. To clarify the poisoning mechanism, the molecular level simulation is applied to the system of Pt on boehmite attacked by a cyclic siloxane which has been detected by experiments and considered as one of poisoning spices. The simulation shows ring-opening reaction of the cyclic siloxane on Pt, then attachment of two ends of the chain-like siloxane to Pt and boehmite, respectively, and that finally the recombination reaction is prevented. This may be the first study to find out the detailed dynamical mechanism of hydrogen recombination catalyst poisoning with cyclic siloxane. (author)

Sorption Modeling and Verification for Off-Gas Treatment

Energy Technology Data Exchange (ETDEWEB)

Tavlarides, Lawrence [Syracuse Univ., NY (United States); Yiacoumi, Sotira [Georgia Inst. of Technology, Atlanta, GA (United States); Tsouris, Costas [Georgia Inst. of Technology, Atlanta, GA (United States); Gabitto, Jorge [Prairie View Texas A& M; DePaoli, David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2016-12-20

This project was successfully executed to provide valuable adsorption data and improve a comprehensive model developed in previous work by the authors. Data obtained were used in an integrated computer program to predict the behavior of adsorption columns. The model is supported by experimental data and has been shown to predict capture of off gas similar to that evolving during the reprocessing of nuclear waste. The computer program structure contains (a) equilibrium models of off-gases with the adsorbate; (b) mass-transfer models to describe off-gas mass transfer to a particle, diffusion through the pores of the particle, and adsorption on the active sites of the particle; and (c) incorporation of these models into fixed bed adsorption modeling, which includes advection through the bed. These models are being connected with the MOOSE (Multiphysics Object-Oriented Simulation Environment) software developed at the Idaho National Laboratory through DGOSPREY (Discontinuous Galerkin Off-gas SeParation and REcoverY) computer codes developed in this project. Experiments for iodine and water adsorption have been conducted on reduced silver mordenite (Ag0Z) for single layered particles. Adsorption apparatuses have been constructed to execute these experiments over a useful range of conditions for temperatures ranging from ambient to 250°C and water dew points ranging from -69 to 19°C. Experimental results were analyzed to determine mass transfer and diffusion of these gases into the particles and to determine which models best describe the single and binary component mass transfer and diffusion processes. The experimental results were also used to demonstrate the capabilities of the comprehensive models developed to predict single-particle adsorption and transients of the adsorption-desorption processes in fixed beds. Models for adsorption and mass transfer have been developed to mathematically describe adsorption kinetics and transport via diffusion and advection

Formation rate of ammonium nitrate in the off-gas line of SRAT and SME in DWPF

International Nuclear Information System (INIS)

Lee, L.

1992-01-01

A mathematical model for the formation rate of ammonium nitrate in the off-gas line of the Sludge Receipt and Adjustment Tank (SRAT) and the Slurry Mixed Evaporator (SME) in DWPF has been developed. The formation rate of ammonium nitrate in the off-gas line depends on pH, temperature, volume and total concentration of ammonia and ammonium ion. Based on a typical SRAT and SME cycle in DWPF, this model predicts the SRAT contributes about 50 lbs of ammonium nitrate while SME contributes about 60 lbs of ammonium nitrate to the off-gas line

Pulmonary hemodynamics and gas exchange in off pump coronary artery bypass grafting.

Science.gov (United States)

Vedin, Jenny; Jensen, Ulf; Ericsson, Anders; Samuelsson, Sten; Vaage, Jarle

2005-10-01

To investigate the influence of cardiopulmonary bypass on pulmonary hemodynamics and gas exchange. Low risk patients admitted for elective coronary artery bypass grafting were randomized to either on (n=25) or off pump (n=25) surgery. Central hemodynamics, gas exchange, and venous admixture were studied during and up to 20 h after surgery. There was no difference in pulmonary vascular resistance index (P=0.16), right ventricular stroke work index (P>0.2), mean pulmonary artery pressure (P>0.2) or pulmonary capillary wedge pressure (P>0.2) between groups. Soon after surgery there was a tendency towards higher cardiac index (P=0.07) in the off pump group. Arterial oxygen tension (P>0.2), hematocrit (P>0.2), venous admixture (P>0.2), and arterial-venous oxygen content difference (P=0.12) did not differ between groups. This prospective, randomized study showed no difference in pulmonary hemodynamics, pulmonary gas exchange, and venous admixture, in low risk patients undergoing off pump compared to on pump coronary artery bypass surgery.

Performance of Power System Stabilizer (UNITROL D) in Benghazi North Power Plant

OpenAIRE

T. Hussein

2011-01-01

The use of power system stabilizers (PSSs) to damp power system swing mode of oscillations is practical important. Our purpose is to retune the power system stabilizer (PSS1A) parameters in Unitrol D produced by ABB– was installed in 1995in Benghazi North Power Plants (BNPPs) at General Electricity Company of Libya (GECOL). The optimal values of the power system stabilizer (PSS1A) parameters are determined off-line by a particle swarm optimization technique (PSO). The obj...

A Gas Chromatographic System for the Detection of Ethylene Gas Using Ambient Air as a Carrier Gas.

Science.gov (United States)

Zaidi, Nayyer Abbas; Tahir, Muhammad Waseem; Vellekoop, Michael J; Lang, Walter

2017-10-07

Ethylene gas is a naturally occurring gas that has an influence on the shelf life of fruit during their transportation in cargo ships. An unintentional exposure of ethylene gas during transportation results in a loss of fruit. A gas chromatographic system is presented here for the detection of ethylene gas. The gas chromatographic system was assembled using a preconcentrator, a printed 3D printed gas chromatographic column, a humidity sensor, solenoid valves, and an electrochemical ethylene gas sensor. Ambient air was used as a carrier gas in the gas chromatographic system. The flow rate was fixed to 10 sccm. It was generated through a mini-pump connected in series with a mass flow controller. The metal oxide gas sensor is discussed with its limitation in ambient air. The results show the chromatogram obtained from metal oxide gas sensor has low stability, drifts, and has uncertain peaks, while the chromatogram from the electrochemical sensor is stable and precise. Furthermore, ethylene gas measurements at higher ppb concentration and at lower ppb concentration were demonstrated with the electrochemical ethylene gas sensor. The system separates ethylene gas and humidity. The chromatograms obtained from the system are stable, and the results are 1.2% repeatable in five similar measurements. The statistical calculation of the gas chromatographic system shows that a concentration of 2.3 ppb of ethylene gas can be detected through this system.

A model for utilizing industrial off-gas to support microalgae cultivation for biodiesel in cold climates

International Nuclear Information System (INIS)

Laamanen, Corey A.; Shang, Helen; Ross, Gregory M.; Scott, John A.

2014-01-01

Highlights: • Development of a model to assess process-coupled algae production in cold climates. • Algae growth temperatures in open tanks can be maintained with industrial off-gas. • Indirect and direct heat application from industrial off-gasses are assessed. • CO 2 -rich off-gas can be bubbled into algae tanks to provide a carbon source. • A nickel smelter’s off-gas is used to demonstrate how waste heat can be repurposed. - Abstract: Lipids produced by microalgae are a promising biofuel feedstock. However, as most commercial mass production of microalgae is in open raceway ponds it is generally considered only a practical option in regions where year-round ambient temperatures remain above 15 °C. To address this issue it has been proposed to couple microalgae production with industries that produce large amounts of waste heat and carbon dioxide (CO 2 ). The CO 2 would provide a carbon source for the microalgae and the waste heat would allow year-round cultivation to be extended to regions that experience seasonal ambient temperatures well below 15 °C. To demonstrate this concept, a dynamic model has been constructed that predicts the impact on algal pond temperature from both bubbled-in off-gas and heat indirectly recovered from off-gas. Simulations were carried out for a variety of global locations using the quantity off-gas and waste energy from a smelter’s operations to determine the volume of microalgae that could be maintained above 15 °C. The results demonstrate the feasibility of year-round microalgae production in climates with relatively cold winter seasons

16 CFR 1203.15 - Positional stability test (roll-off resistance).

Science.gov (United States)

2010-01-01

... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Positional stability test (roll-off resistance). 1203.15 Section 1203.15 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT... over the helmet along the midsagittal plane and attaching the hook over the edge of the helmet as shown...

Off-diagonal long-range order, cycle probabilities, and condensate fraction in the ideal Bose gas.

Science.gov (United States)

Chevallier, Maguelonne; Krauth, Werner

2007-11-01

We discuss the relationship between the cycle probabilities in the path-integral representation of the ideal Bose gas, off-diagonal long-range order, and Bose-Einstein condensation. Starting from the Landsberg recursion relation for the canonic partition function, we use elementary considerations to show that in a box of size L3 the sum of the cycle probabilities of length k>L2 equals the off-diagonal long-range order parameter in the thermodynamic limit. For arbitrary systems of ideal bosons, the integer derivative of the cycle probabilities is related to the probability of condensing k bosons. We use this relation to derive the precise form of the pik in the thermodynamic limit. We also determine the function pik for arbitrary systems. Furthermore, we use the cycle probabilities to compute the probability distribution of the maximum-length cycles both at T=0, where the ideal Bose gas reduces to the study of random permutations, and at finite temperature. We close with comments on the cycle probabilities in interacting Bose gases.

Off gas condenser performance modelling

International Nuclear Information System (INIS)

Cains, P.W.; Hills, K.M.; Waring, S.; Pratchett, A.G.

1989-12-01

A suite of three programmes has been developed to model the ruthenium decontamination performance of a vitrification plant off-gas condenser. The stages of the model are: condensation of water vapour, NO x absorption in the condensate, RuO 4 absorption in the condensate. Juxtaposition of these stages gives a package that may be run on an IBM-compatible desktop PC. Experimental work indicates that the criterion [HNO 2 ] > 10 [RuO 4 ] used to determine RuO 4 destruction in solution is probably realistic under condenser conditions. Vapour pressures of RuO 4 over aqueous solutions at 70 o -90 o C are slightly lower than the values given by extrapolating the ln K p vs. T -1 relation derived from lower temperature data. (author)

Modelling of gas-liquid reactors - stability and dynamic behaviour of gas-liquid mass transfer accompanied by irreversible reaction

NARCIS (Netherlands)

Elk, E.P. van; Borman, P.C.; Kuipers, J.A.M.; Versteeg, G.F.

1999-01-01

The dynamic behaviour and stability of single-phase reacting systems has been investigated thoroughly in the past and design rules for stable operation are available from literature. The dynamic behaviour of gas-liquid processes is considerably more complex and has received relatively little

Temperature Control of Gas Chromatograph Based on Switched Delayed System Techniques

Directory of Open Access Journals (Sweden)

Xiao-Liang Wang

2014-01-01

Full Text Available We address the temperature control problem of the gas chromatograph. We model the temperature control system of the gas chromatograph into a switched delayed system and analyze the stability by common Lyapunov functional technique. The PI controller parameters can be given based on the proposed linear matrix inequalities (LMIs condition and the designed controller can make the temperature of gas chromatograph track the reference signal asymptotically. An experiment is given to illustrate the effectiveness of the stability criterion.

Stabilization of switched nonlinear systems with unstable modes

CERN Document Server

Yang, Hao; Cocquempot, Vincent

2014-01-01

This book provides its reader with a good understanding of the stabilization of switched nonlinear systems (SNS), systems that are of practical use in diverse situations: design of fault-tolerant systems in space- and aircraft; traffic control; and heat propagation control of semiconductor power chips. The practical background is emphasized throughout the book; interesting practical examples frequently illustrate the theoretical results with aircraft and spacecraft given particular prominence. Stabilization of Switched Nonlinear Systems with Unstable Modes treats several different subclasses of SNS according to the characteristics of the individual system (time-varying and distributed parameters, for example), the state composition of individual modes and the degree and distribution of instability in its various modes. Achievement and maintenance of stability across the system as a whole is bolstered by trading off between individual modes which may be either stable or unstable, or by exploiting areas of part...

Stabilizing Gas Bearings In Free-Piston Machines

Science.gov (United States)

Dhar, Manmohan

1995-01-01

Gas bearings and clearance seals between pistons and cylinders in free-piston machines designed to reduce undesired dynamic forces and torques on pistons, gas bearings, and cylinders. Circumferential grooves and drain galleries added to piston or cylinder in improved design. Provides stabilization without significant reduction in length of seal, or significant increase in leakage and consequent reduction of efficiency.

The integrated melter off-gas treatment systems at the West Valley Demonstration Project

Energy Technology Data Exchange (ETDEWEB)

Vance, R.F. [West Valley Nuclear Services Co., Inc., NY (United States)

1995-02-01

The West Valley Demonstration Project was established by Public Law 96-368, the {open_quotes}West Valley Demonstration Project Act, {close_quotes} on October 1, l980. Under this act, Congress directed the Department of Energy to carry out a high level radioactive waste management demonstration project at the Western New York Nuclear Service Center in West Valley, New York. The purpose of this project is to demonstrate solidification techniques which can be used for preparing high level radioactive waste for disposal. In addition to developing this technology, the West Valley Demonstration Project Act directs the Department of Energy to: (1) develop containers suitable for permanent disposal of the high level waste; (2) transport the solidified high level waste to a Federal repository; (3) dispose of low level and transuranic waste produced under the project; and (4) decontaminate and decommission the facilities and materials associated with project activities and the storage tanks originally used to store the liquid high level radioactive waste. The process of vitrification will be used to solidify the high level radioactive liquid wastes into borosilicate glass. This report describes the functions, the controlling design criteria, and the resulting design of the melter off-gas treatment systems which are used in the vitrification process.

Laboratory optimization tests of technetium decontamination of Hanford Waste Treatment Plant low activity waste melter off-gas condensate simulant

Energy Technology Data Exchange (ETDEWEB)

Taylor-Pashow, Kathryn M.L. [Savannah River Site (SRS), Aiken, SC (United States); McCabe, Daniel J. [Savannah River Site (SRS), Aiken, SC (United States)

2015-11-01

The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream (LAW Off-Gas Condensate) from the off-gas system. The baseline plan for disposition of this stream is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility again. Alternate disposition of this stream would eliminate recycling of problematic components, and would enable simplified operation of the LAW melter and the Pretreatment Facilities. Eliminating this stream from recycling within WTP would also decrease the LAW vitrification mission duration and quantity of glass waste.

A new in-gas-laser ionization and spectroscopy laboratory for off-line studies at KU Leuven

International Nuclear Information System (INIS)

Kudryavtsev, Yu.; Creemers, P.; Ferrer, R.; Granados, C.; Gaffney, L.P.; Huyse, M.; Mogilevskiy, E.; Raeder, S.; Sels, S.; Van den Bergh, P.; Van Duppen, P.; Zadvornaya, A.

2016-01-01

The in-gas laser ionization and spectroscopy (IGLIS) technique is used to produce and to investigate short-lived radioactive isotopes at on-line ion beam facilities. In this technique, the nuclear reaction products recoiling out of a thin target are thermalized and neutralized in a high-pressure noble gas, resonantly ionized by the laser beams in a two-step process, and then extracted from the ion source to be finally accelerated and mass separated. Resonant ionization of radioactive species in the supersonic gas jet ensures very high spectral resolution because of essential reduction of broadening mechanisms. To obtain the maximum efficiency and the best spectral resolution, properties of the supersonic jet and the laser beams must be optimized. To perform these studies a new off-line IGLIS laboratory, including a new high-repetition-rate laser system and a dedicated off-line mass separator, has been commissioned. In this article, the specifications of the different components necessary to achieve optimum conditions in laser-spectroscopy studies of radioactive beams using IGLIS are discussed and the results of simulations are presented.

Stability and special solutions to the conducting dusty gas model

International Nuclear Information System (INIS)

Calmelet, C.J.

1987-01-01

Models of the flow of a dusty, conducting and non-conducting gas are examined. Exact solutions for a conducting dusty gas model in the presence of a magnetic field are developed for two different flow domains. The exact solutions are calculated in the cases of negligible and non-negligible induced magnetic field. Stability theorems are developed which depend on the flow parameters of the dusty gas and the magnetic field. In particular, a universal stability theorem is obtained when the dusty gas flow is electrically conducting in the presence of an applied magnetic field, and the dust particles are non-uniformly distributed

Asymptotic theory of neutral stability of the Couette flow of a vibrationally excited gas

Science.gov (United States)

Grigor'ev, Yu. N.; Ershov, I. V.

2017-01-01

An asymptotic theory of the neutral stability curve for a supersonic plane Couette flow of a vibrationally excited gas is developed. The initial mathematical model consists of equations of two-temperature viscous gas dynamics, which are used to derive a spectral problem for a linear system of eighth-order ordinary differential equations within the framework of the classical linear stability theory. Unified transformations of the system for all shear flows are performed in accordance with the classical Lin scheme. The problem is reduced to an algebraic secular equation with separation into the "inviscid" and "viscous" parts, which is solved numerically. It is shown that the thus-calculated neutral stability curves agree well with the previously obtained results of the direct numerical solution of the original spectral problem. In particular, the critical Reynolds number increases with excitation enhancement, and the neutral stability curve is shifted toward the domain of higher wave numbers. This is also confirmed by means of solving an asymptotic equation for the critical Reynolds number at the Mach number M ≤ 4.

Regulatory off-gas analysis from the evaporation of Hanford simulated waste spiked with organic compounds.

Science.gov (United States)

Saito, Hiroshi H; Calloway, T Bond; Ferrara, Daro M; Choi, Alexander S; White, Thomas L; Gibson, Luther V; Burdette, Mark A

2004-10-01

After strontium/transuranics removal by precipitation followed by cesium/technetium removal by ion exchange, the remaining low-activity waste in the Hanford River Protection Project Waste Treatment Plant is to be concentrated by evaporation before being mixed with glass formers and vitrified. To provide a technical basis to permit the waste treatment facility, a relatively organic-rich Hanford Tank 241-AN-107 waste simulant was spiked with 14 target volatile, semi-volatile, and pesticide compounds and evaporated under vacuum in a bench-scale natural circulation evaporator fitted with an industrial stack off-gas sampler at the Savannah River National Laboratory. An evaporator material balance for the target organics was calculated by combining liquid stream mass and analytical data with off-gas emissions estimates obtained using U.S. Environmental Protection Agency (EPA) SW-846 Methods. Volatile and light semi-volatile organic compounds (1 mm Hg vapor pressure) in the waste simulant were found to largely exit through the condenser vent, while heavier semi-volatiles and pesticides generally remain in the evaporator concentrate. An OLI Environmental Simulation Program (licensed by OLI Systems, Inc.) evaporator model successfully predicted operating conditions and the experimental distribution of the fed target organics exiting in the concentrate, condensate, and off-gas streams, with the exception of a few semi-volatile and pesticide compounds. Comparison with Henry's Law predictions suggests the OLI Environmental Simulation Program model is constrained by available literature data.

Study of plasma off-gas treatment from spent ion exchange resin pyrolysis.

Science.gov (United States)

Castro, Hernán Ariel; Luca, Vittorio; Bianchi, Hugo Luis

2017-03-23

Polystyrene divinylbenzene-based ion exchange resins are employed extensively within nuclear power plants (NPPs) and research reactors for purification and chemical control of the cooling water system. To maintain the highest possible water quality, the resins are regularly replaced as they become contaminated with a range of isotopes derived from compromised fuel elements as well as corrosion and activation products including 14 C, 60 Co, 90 Sr, 129 I, and 137 Cs. Such spent resins constitute a major proportion (in volume terms) of the solid radioactive waste generated by the nuclear industry. Several treatment and conditioning techniques have been developed with a view toward reducing the spent resin volume and generating a stable waste product suitable for long-term storage and disposal. Between them, pyrolysis emerges as an attractive option. Previous work of our group suggests that the pyrolysis treatment of the resins at low temperatures between 300 and 350 °C resulted in a stable waste product with a significant volume reduction (>50%) and characteristics suitable for long-term storage and/or disposal. However, another important issue to take into account is the complexity of the off-gas generated during the process and the different technical alternatives for its conditioning. Ongoing work addresses the characterization of the ion exchange resin treatment's off-gas. Additionally, the application of plasma technology for the treatment of the off-gas current was studied as an alternative to more conventional processes utilizing oil- or gas-fired post-combustion chambers operating at temperatures in excess of 1000 °C. A laboratory-scale flow reactor, using inductively coupled plasma, operating under sub-atmospheric conditions was developed. Fundamental experiments using model compounds have been performed, demonstrating a high destruction and removal ratio (>99.99%) for different reaction media, at low reactor temperatures and moderate power consumption

Off-gas characteristics of defense waste vitrification using liquid-fed Joule-heated ceramic melters

International Nuclear Information System (INIS)

Goles, R.W.; Sevigny, G.J.

1983-09-01

Off-gas and effluent characterization studies have been established as part of a PNL Liquid-Fed Ceramic Melter development program supporting the Savannah River Laboratory Defense Waste Processing Facility (SRL-DWPF). The objectives of these studies were to characterize the gaseous and airborne emission properties of liquid-fed joule-heated melters as a function of melter operational parameters and feed composition. All areas of off-gas interest and concern including effluent characterization, emission control, flow rate behavior and corrosion effects have been studied using alkaline and formic-acid based feed compositions. In addition, the behavioral patterns of gaseous emissions, the characteristics of melter-generated aerosols and the nature and magnitude of melter effluent losses have been established under a variety of feeding conditions with and without the use of auxiliary plenum heaters. The results of these studies have shown that particulate emissions are responsible for most radiologically important melter effluent losses. Melter-generated gases have been found to be potentially flammable as well as corrosive. Hydrogen and carbon monoxide present the greatest flammability hazard of the combustibles produced. Melter emissions of acidic volatile compounds of sulfur and the halogens have been responsible for extensive corrosion observed in melter plenums and in associated off-gas lines and processing equipment. The use of auxiliary plenum heating has had little effect upon melter off-gas characteristics other than reducing the concentrations of combustibles

A new boil-off gas re-liquefaction system for LNG carriers based on dual mixed refrigerant cycle

Science.gov (United States)

Tan, Hongbo; Shan, Siyu; Nie, Yang; Zhao, Qingxuan

2018-06-01

A new boil-off gas (BOG) re-liquefaction system for LNG carriers has been proposed to improve the system energy efficiency. Two cascade mixed refrigerant cycles (or dual mixed refrigerant cycle, DMR) are used to provide the cooling capacity for the re-liquefaction of BOG. The performance of the new system is analysed on the basis of the thermodynamic data obtained in the process simulation in Aspen HYSYS software. The results show that the power consumed in the BOG compressor and the high-temperature mixed refrigerant compressor could be saved greatly due to the reduced mass flow rates of the processed fluids. Assuming the re-liquefaction capacity of the investigated system is 4557.6 kg/h, it is found that the total power consumption can be reduced by 25%, from 3444 kW in the existing system to 2585.8 kW in the proposed system. The coefficient of performance (COP) of 0.25, exergy efficiency of 41.3% and the specific energy consumption (SEC) of 0.589 kWh/kg(LNG) could be achieved in the new system. It exhibits 33% of improvement in the COP and exergy efficiency in comparison with the corresponding values of the existing system. It indicates that employing the DMR based BOG re-liquefaction system could improve the system energy efficiency of LNG carriers substantially.

Off-Gas Analysis During the Vitrification of Hanford Radioactive Waste Samples

International Nuclear Information System (INIS)

Ha, B.C.; Ferrara, D.M.; Crawford, C.L.; Choi, A.S.; Bibler, N.E.

1998-01-01

This paper describes the off-gas analysis of samples collected during the radioactive vitrification experiments. Production and characterization of the Hanford waste-containing LAW and HAW glasses are presented in related reports from this conference

A Novel Boil-Off Gas Re-Liquefaction Using a Spray Recondenser for Liquefied Natural-Gas Bunkering Operations

Directory of Open Access Journals (Sweden)

Jiheon Ryu

2016-11-01

Full Text Available This study presents the design of a novel boil-off gas (BOG re-liquefaction technology using a BOG recondenser system. The BOG recondenser system targets the liquefied natural gas (LNG bunkering operation, in which the BOG phase transition occurs in a pressure vessel instead of a heat exchanger. The BOG that is generated during LNG bunkering operation is characterized as an intermittent flow with various peak loads. The system was designed to temporarily store the transient BOG inflow, condense it with subcooled LNG and store the condensed liquid. The superiority of the system was verified by comparing it with the most extensively employed conventional re-liquefaction system in terms of consumption energy and via an exergy analysis. Static simulations were conducted for three compositions; the results indicated that the proposed system provided 0 to 6.9% higher efficiencies. The exergy analysis indicates that the useful work of the conventional system is 24.9%, and the useful work of the proposed system is 26.0%. Process dynamic simulations of six cases were also performed to verify the behaviour of the BOG recondenser system. The results show that the pressure of the holdup in the recondenser vessel increased during the BOG inflow mode and decreased during the initialization mode. The maximum pressure of one of the bunkering cases was 3.45 bar. The system encountered a challenge during repetitive operations due to overpressurizing of the BOG recondenser vessel.

Off-gassing induced tracer release from molten basalt pools

International Nuclear Information System (INIS)

Cronenberg, A.W.; Callow, R.A.

1994-01-01

Two in situ vitrification (ISV) field tests were conducted at the Idaho National Engineering Laboratory (INEL) during the summer of 1990 to assess ISV suitability for long-term stabilization of buried waste that contains transuranic and other radionuclide contaminants. The ISV process uses electrical resistance heating to melt buried waste and soil in place, which upon cooldown and resolidification fixes the waste into a vitrified (glass-like) form. In these two ISV field tests, small quantities of rare-earth oxides (tracers DY 2 O 3 , Yb 2 O 3 , and Tb 4 O 7 ) were placed in the test pits to simulate the presence of plutonium oxides and assess plutonium retention/release behavior. The analysis presented in this report indicates that dissolution of tracer oxides into basaltic melts can be expected with subsequent tracer molecular or microparticle carry-off by escaping gas bubbles, which is similar to adsorptive bubble separation and ion flotation processes employed in the chemical industry to separate dilute heavy species from liquids under gas sparging conditions. Gaseous bubble escape from the melt surface and associated aerosolization is believed to be responsible for small quantities of tracer ejection from the melt surface to the cover hood and off-gas collection system. Methods of controlling off-gassing during ISV would be expected to improve the overall retention of such heavy oxide contaminants during melting/vitrification of buried waste

Interim report on testing of off-gas treatment technologies for abatement of atmospheric emissions of chlorinated volatile organic compounds

International Nuclear Information System (INIS)

Haselow, J.S.; Jarosch, T.R.; Rossabi, J.; Burdick, S.; Lombard, K.

1993-12-01

The purpose of this report is to briefly summarize the results to date of the off-gas treatment program for atmospheric emissions of chlorinated volatile organic compounds (CVOCs), in particular trichloroethylene (TCE) and perchloroethylene (PCE). This program is part of the Department of Energy's Office of Technology Development's Integrated Demonstration for Treatment of Organics in Soil and Water at a Non-Arid Site. The off-gas treatment program was initiated after testing of in-situ air stripping with horizontal wells was completed. That successful test expectedly produced atmospheric emissions of CVOCs that were unabated. It was decided after that test that an off-gas treatment program would complement the Integrated Demonstration not only because off-gas treatment is an integral portion of remediation of CVOC contamination in groundwater and soil but also because several technologies were being developed across the US to mitigate CVOC emissions. A single platform for testing off-gas treatment technologies would facilitate systematic and unbiased evaluation of the emerging technologies

Removal of carbon dioxide in reprocessing spent nuclear fuel off gas by adsorption

International Nuclear Information System (INIS)

Fukumatsu, Teruki; Munakata, Kenzo; Tanaka, Kenji; Yamatsuki, Satoshi; Nishikawa, Masabumi

1998-01-01

The off gas produced by reprocessing spent nuclear fuel includes various radioactivities and these nuclei should be removed. In particular, 14 C mainly released as the form of carbon dioxide is one of the most required gaseous radioactivities to be removed because it has long a half-life. One of the methods to remove gaseous nuclei is the use of adsorption technique. The off gas contains water vapor which influences adsorption process of carbon dioxide. In this report, behavior of adsorption of carbon dioxide on various adsorbent and influence on adsorption behavior of carbon dioxide by containing water vapor are discussed. (author)

Development of a technique for the efficiency calibration of a HPGe detector for the off gas samples of a nuclear reactor

International Nuclear Information System (INIS)

Singh, Sarbjit; Agarwal, Chhavi; Ramaswami, A.; Manchanda, V.K.

2007-01-01

Regular monitoring of off gases released to the environment from a nuclear reactor is mandatory. The gaseous fission products are estimated by gamma ray spectrometry using a HPGe detector coupled to a multichannel analyser. In view of the lack of availability of gaseous fission products standards, an indirect method based on the charcoal absorption technique was developed for the efficiency calibration of HPGe detector system using 133B a and 152E u standards. The known activities of 133B a and 152E u are uniformly distributed in a vial having activated charcoal and counted on the HPGe detector system at liquid nitrogen temperature to determine the gamma ray efficiency for the vial having activated charcoal. The ratio of the gamma ray efficiencies of off gas present in the normal vial and the vial having activated charcoal at liquid nitrogen temperature are used to determine the gamma ray efficiency of off gas present in the normal vial. (author)

Frequency stabilization of a He-Ne gas laser by controlling refractive index of laser plasma

International Nuclear Information System (INIS)

Xie Yi; Wu Yizun

1991-01-01

A new way to stabilize the frequency of a Zeeman He-Ne gas laser is described. The laser frequency is stabilized by controlling the refractive index of the laser plasma. It does not need a gas laser tube with a piezoelectric ceramic (PZT) made by special technology. As the phase-locking technology is used in the laser servo system, the self-beat frequency is a constant and the frequency stability is better than 2.2 x 10 -11 (averaging time = 10 sec.). The long term frequency fluctuation never exceeded 2 x 10 -8 during two months. The frequency of the locked point can be adjusted continuously in the range of over 200 MHz

Development and Testing of the Advanced CHP System Utilizing the Off-Gas from the Innovative Green Coke Calcining Process in Fluidized Bed

Energy Technology Data Exchange (ETDEWEB)

Chudnovsky, Yaroslav [Gas Technology Inst., Des Plaines, IL (United States); Kozlov, Aleksandr [Gas Technology Inst., Des Plaines, IL (United States)

2013-08-15

Green petroleum coke (GPC) is an oil refining byproduct that can be used directly as a solid fuel or as a feedstock for the production of calcined petroleum coke. GPC contains a high amount of volatiles and sulfur. During the calcination process, the GPC is heated to remove the volatiles and sulfur to produce purified calcined coke, which is used in the production of graphite, electrodes, metal carburizers, and other carbon products. Currently, more than 80% of calcined coke is produced in rotary kilns or rotary hearth furnaces. These technologies provide partial heat utilization of the calcined coke to increase efficiency of the calcination process, but they also share some operating disadvantages. However, coke calcination in an electrothermal fluidized bed (EFB) opens up a number of potential benefits for the production enhancement, while reducing the capital and operating costs. The increased usage of heavy crude oil in recent years has resulted in higher sulfur content in green coke produced by oil refinery process, which requires a significant increase in the calcinations temperature and in residence time. The calorific value of the process off-gas is quite substantial and can be effectively utilized as an “opportunity fuel” for combined heat and power (CHP) production to complement the energy demand. Heat recovered from the product cooling can also contribute to the overall economics of the calcination process. Preliminary estimates indicated the decrease in energy consumption by 35-50% as well as a proportional decrease in greenhouse gas emissions. As such, the efficiency improvement of the coke calcinations systems is attracting close attention of the researchers and engineers throughout the world. The developed technology is intended to accomplish the following objectives: - Reduce the energy and carbon intensity of the calcined coke production process. - Increase utilization of opportunity fuels such as industrial waste off-gas from the novel

Design of Simulation Product for Stability of Electric Power System Using Power System Stabilizer and Optimal Control

Science.gov (United States)

Junaidi, Agus; Hamid, K. Abdul

2018-03-01

This paper will discuss the use of optimal control and Power System Stabilizer (PSS) in improving the oscillation of electric power system. Oscillations in the electric power system can occur due to the sudden release of the load (Switcing-Off). The oscillation of an unstable system for a long time causes the equipment to work in an interruption. To overcome this problem, a control device is required that can work effectively in repairing the oscillation. The power system is modeled from the Single Machine Infinite Bus Model (SMIB). The state space equation is used to mathematically model SMIB. SMIB system which is a plant will be formed togetherness state variables (State-Space), using riccati equation then determined the optimal gain as controller plant. Plant is also controlled by Power Stabilizer System using phase compensation method. Using Matlab Software based simulation will be observed response of rotor speed change and rotor angle change for each of the two controlling methods. Simulation results using the Simulink-MATLAB 6.1 software will compare the analysis of the plant state in Open loop state and use the controller. The simulation response shows that the optimal control and PSS can improve the stability of the power system in terms of acceleration to achieve settling-time and Over Shoot improvement. From the results of both methods are able to improve system performance.

A quality evaluation of stabilization of rotation frequency of gas-diesel engines when using an adaptive automatic control system

Science.gov (United States)

Zhilenkov, A. A.; Efremov, A. A.

2017-02-01

A possibility of quality improvement of stabilization of rotation frequency of the gas-diesels used as prime mover of generator set in the multigenerator units working for abruptly variable load of large power is considered. An evaluation is made on the condition of fuzzy controller use developed and described by the authors in a number of articles. An evaluation has shown that theoretically, the revolution range of a gas-diesel engine may be reduced 25-30 times in case of optimal settings of the controller in the whole power range. The results of modelling showing a considerable quality improvement of transient processes in the investigated system during a sharp change of loading are presented in this article.

Selective absorption pilot plant for decontamination of fuel reprocessing plant off-gas

Energy Technology Data Exchange (ETDEWEB)

Stephenson, M.J.; Eby, R.S.; Huffstetler, V.C.

1977-10-01

A fluorocarbon-based selective absorption process for removing krypton-85, carbon-14, and radon-222 from the off-gas of conventional light water and advanced reactor fuel reprocessing plants is being developed at the Oak Ridge Gaseous Diffusion Plant in conjunction with fuel recycle work at the Oak Ridge National Laboratory and at the Savannah River Laboratory. The process is characterized by an especially high tolerance for many other reprocessing plant off-gas components. This report presents detailed drawings and descriptions of the second generation development pilot plant as it has evolved after three years of operation. The test facility is designed on the basis of removing 99% of the feed gas krypton and 99.9% of the carbon and radon, and can handle a nominal 15 scfm (425 slm) of contaminated gas at pressures from 100 to 600 psig (7.0 to 42.2 kg/cm/sup 2/) and temperatures from minus 45 to plus 25/sup 0/F (-43 to -4/sup 0/C). Part of the development program is devoted to identifying flowsheet options and simplifications that lead to an even more economical and reliable process. Two of these applicative flowsheets are discussed.

The regulatory regime for gas: a system in danger of coming off the rails

International Nuclear Information System (INIS)

Nangle, B.

2000-01-01

The Australian Gas Association (AGA) and its members are getting restless as it becomes more apparent the promised benefits of deregulation are imposing more costs and controls on an industry that owns and operates infrastructure valued at $15bn in heavily regulated markets. AGA Chief Executive Bill Nable used the Northern Territory Electricity and Gas Review in Darwin to examine the state of the gas regulatory regime. The pure reform model envisaged: 1. Multiple producers dealing often directly with large customers and retailers; 2. Open and transparent third party access to transmission (high pressure pipelines) and distribution (local low pressure pipeline networks) systems; and 3. A greater number of energy retailers competing for customers who are free to choose who they purchase their gas from. Energy sector reforms were generally pursued in a coordinated fashion through Commonwealth and State leaders forum - COAG. For gas, as with electricity, this meant separating out (unbundling) previously integrated gas utilities to engender competition and to lower prices - initially for major export and import competing sectors and eventually residential and small business customers. Although the reforms are laudable and have industry support, senior gas industry executives spoke about their concerns and caution about the negative impact the 'Third Party Access Code for Natural Gas and Pipeline Systems' may have for the gas supply industry

Atmospheric Pressure Effects on Cryogenic Storage Tank Boil-Off

Science.gov (United States)

Sass, J. P.; Frontier, C. R.

2007-01-01

The Cryogenics Test Laboratory (CTL) at the Kennedy Space Center (KSC) routinely utilizes cryostat test hardware to evaluate comparative and absolute thermal conductivities of a wide array of insulation systems. The test method is based on measurement of the flow rate of gas evolved due to evaporative boil-off of a cryogenic liquid. The gas flow rate typically stabilizes after a period of a couple of hours to a couple of days, depending upon the test setup. The stable flow rate value is then used to calculate the thermal conductivity for the insulation system being tested. The latest set of identical cryostats, 1,000-L spherical tanks, exhibited different behavior. On a macro level, the flow rate did stabilize after a couple of days; however the stable flow rate was oscillatory with peak to peak amplitude of up to 25 percent of the nominal value. The period of the oscillation was consistently 12 hours. The source of the oscillation has been traced to variations in atmospheric pressure due to atmospheric tides similar to oceanic tides. This paper will present analysis of this phenomenon, including a calculation that explains why other cryostats are not affected by it.

The impact of fluid advection on gas hydrate stability: Investigations at sites of methane seepage offshore Costa Rica

Science.gov (United States)

Crutchley, G. J.; Klaeschen, D.; Planert, L.; Bialas, J.; Berndt, C.; Papenberg, C.; Hensen, C.; Hornbach, M. J.; Krastel, S.; Brueckmann, W.

2014-09-01

Fluid flow through marine sediments drives a wide range of processes, from gas hydrate formation and dissociation, to seafloor methane seepage including the development of chemosynthetic ecosystems, and ocean acidification. Here, we present new seismic data that reveal the 3D nature of focused fluid flow beneath two mound structures on the seafloor offshore Costa Rica. These mounds have formed as a result of ongoing seepage of methane-rich fluids. We show the spatial impact of advective heat flow on gas hydrate stability due to the channelled ascent of warm fluids towards the seafloor. The base of gas hydrate stability (BGHS) imaged in the seismic data constrains peak heat flow values to ∼60 mW m and ∼70 mW m beneath two separate seep sites known as Mound 11 and Mound 12, respectively. The initiation of pronounced fluid flow towards these structures was likely controlled by fault networks that acted as efficient pathways for warm fluids ascending from depth. Through the gas hydrate stability zone, fluid flow has been focused through vertical conduits that we suggest developed as migrating fluids generated their own secondary permeability by fracturing strata as they forced their way upwards towards the seafloor. We show that Mound 11 and Mound 12 (about 1 km apart on the seafloor) are sustained by independent fluid flow systems through the hydrate system, and that fluid flow rates across the BGHS are probably similar beneath both mounds. 2D seismic data suggest that these two flow systems might merge at approximately 1 km depth, i.e. much deeper than the BGHS. This study provides a new level of detail and understanding of how channelled, anomalously-high fluid flow towards the seafloor influences gas hydrate stability. Thus, gas hydrate systems have good potential for quantifying the upward flow of subduction system fluids to seafloor seep sites, since the fluids have to interact with and leave their mark on the hydrate system before reaching the seafloor.

Laboratory Optimization Tests of Technetium Decontamination of Hanford Waste Treatment Plant Direct Feed Low Activity Waste Melter Off-Gas Condensate Simulant

Energy Technology Data Exchange (ETDEWEB)

Taylor-Pashow, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); McCabe, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-12-23

The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream (LAW Off-Gas Condensate) from the off-gas system. The baseline plan for disposition of this stream is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility. Alternate disposition of this stream would eliminate recycling of problematic components, and would enable less integrated operation of the LAW melter and the Pretreatment Facilities. Eliminating this stream from recycling within WTP would also decrease the LAW vitrification mission duration and quantity of glass waste.

Comparison of thermochemically calculated and measured dioxin contents in the off-gas of a sinter plant

Energy Technology Data Exchange (ETDEWEB)

Spencer, P; Eriksson, G; Neuschuelz, D [Lehrstuhl fuer Theoretische Huettenkunde, Aachen (Germany)

1998-12-31

Polychlorinated dibenzo-p-dioxins and dibenzo-furans form a family of more than 200 compounds which are relatively stable in the biosphere and tend to accumulate in the human body. The tetra- to hexa-chlorinated dioxins and furans are considered highly toxic. To facilitate the assessment of the total toxicity of dioxin and furan mixtures, the estimated toxic effects of the individual compounds relative to the 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) were introduced as Toxic Equivalent Factors which yield, when multiplied with the respective concentrations, the Toxic Equivalent (TE) of the mixture. Toxic dioxins and furans are unintentionally formed in a number of industrial combustion processes such as waste incineration and iron ore sintering, in the chemical industry and in household heating. To keep the emissions as low as possible, off-gas clearing systems for the collection of dioxins and furans are increasingly prescribed by the authorities. In addition, it appears desirable to select process conditions that are unfavourable for the formation of these compounds. A simulation of the relevant processes on the basis of thermodynamic data may be helpful in defining such process conditions. To simulate dioxin formation in the sintering process, all major gas-solid reactions taking place in the sinter bed must also be simulated. A sufficiently accurate reproduction of the off-gas compositions along the length of the sinter strand requires detailed assumptions concerning the relative amounts of `active` O{sub 2} as well as the distribution of reacting carbon and water over the strand length. From this basis, an equilibrium calculation for the gas/solid reactions at the sintering temperature of 1150 deg C and an equilibrium calculation restricted to the gas phase at 700 deg C produced values for the concentrations of the major off-gas constituents in very good agreement with the measured values. The further assumption that below 700 deg C all reactions are frozen

Comparison of thermochemically calculated and measured dioxin contents in the off-gas of a sinter plant

Energy Technology Data Exchange (ETDEWEB)

Spencer, P.; Eriksson, G.; Neuschuelz, D. [Lehrstuhl fuer Theoretische Huettenkunde, Aachen (Germany)

1997-12-31

Polychlorinated dibenzo-p-dioxins and dibenzo-furans form a family of more than 200 compounds which are relatively stable in the biosphere and tend to accumulate in the human body. The tetra- to hexa-chlorinated dioxins and furans are considered highly toxic. To facilitate the assessment of the total toxicity of dioxin and furan mixtures, the estimated toxic effects of the individual compounds relative to the 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) were introduced as Toxic Equivalent Factors which yield, when multiplied with the respective concentrations, the Toxic Equivalent (TE) of the mixture. Toxic dioxins and furans are unintentionally formed in a number of industrial combustion processes such as waste incineration and iron ore sintering, in the chemical industry and in household heating. To keep the emissions as low as possible, off-gas clearing systems for the collection of dioxins and furans are increasingly prescribed by the authorities. In addition, it appears desirable to select process conditions that are unfavourable for the formation of these compounds. A simulation of the relevant processes on the basis of thermodynamic data may be helpful in defining such process conditions. To simulate dioxin formation in the sintering process, all major gas-solid reactions taking place in the sinter bed must also be simulated. A sufficiently accurate reproduction of the off-gas compositions along the length of the sinter strand requires detailed assumptions concerning the relative amounts of `active` O{sub 2} as well as the distribution of reacting carbon and water over the strand length. From this basis, an equilibrium calculation for the gas/solid reactions at the sintering temperature of 1150 deg C and an equilibrium calculation restricted to the gas phase at 700 deg C produced values for the concentrations of the major off-gas constituents in very good agreement with the measured values. The further assumption that below 700 deg C all reactions are frozen

Automatic gas-levitation system for vacuum deposition of laser-fusion targets

International Nuclear Information System (INIS)

Jordan, C.W.; Cameron, G.R.; Krenik, R.M.; Crane, J.K.

1981-01-01

An improved simple system has been developed to gas-levitate microspheres during vacuum-deposition processes. The automatic operation relies on two effects: a lateral stabilizing force provided by a centering-ring; and an automatically incremented gas metering system to offset weight increases during coating

Comparison of high temperature gas particulate collectors for low level radwaste incinerator volume reduction systems

International Nuclear Information System (INIS)

Moscardini, R.L.; Johnston, J.R.; Waters, R.M.; Zievers, J.F.

1983-01-01

Incinerator system off-gases must be treated to prevent the release of particulates, noxious gases and radioactive elements to the environment. Fabric filters, venturi scrubbers, cyclone separators, an ceramic or metal filter candles have been used for particulate removal. Dry high temperature particulate collectors have the advantage of not creating additional liquid wastes. This paper presents a graphical comparison of different methods for filtering particles from high temperature incineration system off-gases. Eight methods of off-gas handling are compared. A much larger group may be present, but some judicious selection of different, but related systems was done for this paper based on experience with the Combustion Engineering Waste Incineration System (CE/WIS) Prototype. The eight types are: Inertial Devices, Electrostatic Precipitators (ESP), Standard Fabric Bags, Woven Ceramic Bags, Granular Beds, Sintered Metal Tubes, Felted Ceramic Bags and Ceramic Filter Candles. For high temperature LLRW particulate collection in incinerator off-gas systems, ceramic filter candles are the best overall choice

A Literature Survey to Identify Potentially Volatile Iodine-Bearing Species Present in Off-Gas Streams

Energy Technology Data Exchange (ETDEWEB)

Bruffey, S. H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Spencer, B. B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Strachan, D. M. [Strata-G, Knoxville, TN (United States); Jubin, R. T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Soelberg, N. R. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Riley, B. J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2015-06-30

Four radionuclides have been identified as being sufficiently volatile in the reprocessing of nuclear fuel that their gaseous release needs to be controlled to meet regulatory requirements (Jubin et al. 2011, 2012). These radionuclides are 3H, 14C, 85Kr, and 129I. Of these, 129I has the longest half-life and potentially high biological impact. Accordingly, control of the release of 129I is most critical with respect to the regulations for the release of radioactive material in stack emissions. It is estimated that current EPA regulations (EPA 2010) would require any reprocessing plant in the United States to limit 129I release to less than 0.05 Ci/MTIHM for a typical fuel burnup of 55 gigawatt days per metric tonne (GWd/t) (Jubin 2011). The study of inorganic iodide in off-gas systems has been almost exclusively limited to I2 and the focus of organic iodide studies has been CH3I. In this document, we provide the results of an examination of publically available literature that is relevant to the presence and sources of both inorganic and organic iodine-bearing species in reprocessing plants. We especially focus on those that have the potential to be poorly sequestered with traditional capture methodologies. Based on the results of the literature survey and some limited thermodynamic modeling, the inorganic iodine species hypoiodous acid (HOI) and iodine monochloride (ICl) were identified as potentially low-sorbing iodine species that could present in off-gas systems. Organic species of interest included both short chain alkyl iodides such as methyl iodide (CH3I) and longer alkyl iodides up to iodododecane (C10H21I). It was found that fuel dissolution may provide conditions conducive to HOI formation and has been shown to result in volatile long-chain alkyl iodides, though these may not volatilize until later in the reprocessing sequence. Solvent extraction processes were found to be significant sources of various organic iodine-bearing species; formation of these

Optimization of UA of heat exchangers and BOG compressor exit pressure of LNG boil-off gas reliquefaction system using exergy analysis

Science.gov (United States)

Kochunni, Sarun Kumar; Ghosh, Parthasarathi; Chowdhury, Kanchan

2015-12-01

Boil-off gas (BOG) generation and its handling are important issues in Liquefied natural gas (LNG) value chain because of economic, environment and safety reasons. Several variants of reliquefaction systems of BOG have been proposed by researchers. Thermodynamic analyses help to configure them and size their components for improving performance. In this paper, exergy analysis of reliquefaction system based on nitrogen-driven reverse Brayton cycle is carried out through simulation using Aspen Hysys 8.6®, a process simulator and the effects of heat exchanger size with and without related pressure drop and BOG compressor exit pressure are evaluated. Nondimensionalization of parameters with respect to the BOG load allows one to scale up or down the design. The process heat exchanger (PHX) requires much higher surface area than that of BOG condenser and it helps to reduce the quantity of methane vented out to atmosphere. As pressure drop destroys exergy, optimum UA of PHX decreases for highest system performance if pressure drop is taken into account. Again, for fixed sizes of heat exchangers, as there is a range of discharge pressures of BOG compressor at which the loss of methane in vent minimizes, the designer should consider choosing the pressure at lower value.

Shell launches its Claus off-gas desulfurization process

Energy Technology Data Exchange (ETDEWEB)

Groenendaal, W; van Meurs, H C.A.

1972-01-01

The Shell Flue Gas Desulfurization (SFGD) Process was developed for removal of sulfur oxides from flue gases originating from oil-fired boilers or furnaces. It can also be used to remove sulfur dioxide from Claus sulfur recovery tail gases if they are combined with boiler/furnace flue gases. For Claus tail gas only, the Shell Claus off-gas desulfurization process was developed. Claus unit operation and desulfurization by low temperature Claus processes and conversion/concentration processes are discussed. The new Shell process consists of a conversion/concentration process involving a reduction section and an amine absorption section. In the reduction section, all sulfur compounds and free sulfur are completely reduced to hydrogen sulfide with hydrogen, or hydrogen plus carbon monoxide, over a cobalt/molybdenum-on-alumina catalyst at a temperature of about 300/sup 0/C. Extensive bench scale studies on the reduction system have been carried out. A life test of more than 4000 hr showed a stable activity of the reduction catalyst, which means that in commercial units, very long catalyst lives can be expected. The commercial feasibility of the reduction section was further demonstrated in the Godorf refinery of Deutsche Shell AG. More than 80 absorption units using alkanolamine (AIDP) solutions have been installed. Bench scale studies of the ADIP absorption units were compared to commercial experience.The total capital investment of the new Shell process is 0.7, 2.0, and 3.2 $ times 10 to the 6th power for 100, 500, and 1000 tons of sulfur/sd capacity Claus units, respectively. The total operating costs for these units are, respectively, 610, 1930 and 3310 $/stream day. The capital investment corresponds to about 75% of the capital investment of the preceding Claus unit.

Application of Arma Technique For Operation Stability of RSG-Gas

International Nuclear Information System (INIS)

Djudjuratisbela, Udju

2000-01-01

Application Of Arma Technique For Operation Stability Of RSG-Gas. Application of Fast Fourier Transport (FFT) method in the noise experiments data had been conducted to reactor kinetic parameter determination of RSG-Gas. Reactor stability that has closed relation to operation safety has not been measured yet. Noise analysis method and ARMA (Auto Regressive Moving Average) technique that has capability to identify mathematical model of the noise experimental data can be used for determination of kinetic/dynamic characteristic equation and its roots. From the roots of reactor characteristic equation, magnitude of natural frequency (fn), damping ratio (xi), damping frequency (fd), decay ratio (delta) and then reactor stability can be calculated

Oxidation and Condensation of Zinc Fume From Zn-CO2-CO-H2O Streams Relevant to Steelmaking Off-Gas Systems

International Nuclear Information System (INIS)

Bronson, Tyler Mark; Ma, Naiyang; Zhu, Liang Zhu; Sohn, Hong Yong

2017-01-01

Here the objective of this research was to study the condensation of zinc vapor to metallic zinc and zinc oxide solid under varying environments to investigate the feasibility of in-process separation of zinc from steelmaking off-gas dusts. Water vapor content, temperature, degree of cooling, gas composition, and initial zinc partial pressure were varied to simulate the possible conditions that can occur within steelmaking off-gas systems, limited to Zn-CO 2 -CO-H 2 O gas compositions. The temperature of deposition and the effect of rapidly quenching the gas were specifically studied. A homogeneous nucleation model for applicable experiments was applied to the analysis of the experimental data. It was determined that under the experimental conditions, oxidation of zinc vapor by H 2 O or CO 2 does not occur above 1108 K (835 °C) even for highly oxidizing streams (CO 2 /CO = 40/7). Rate expressions that correlate CO 2 and H 2 O oxidation rates to gas composition, partial pressure of water vapor, temperature, and zinc partial pressure were determined to be as follows: Rate ((mol)/(m 2 s)) = 406 exp ((−50.2kJ/mol)/(RT)) (pZnpCO 2 − PCO/K eq CO 2 ) ((mol)/(m 2 xs)) Rate (((mol)/(m 2 s))) = 32.9 exp (((−13.7kJ/mol)/(RT))) (pZnPH 2 O − PH 2 /K eq H 2 O) ((mol)/(m 2 xs)). It was proven that a rapid cooling rate (500 K/s) significantly increases the ratio of metallic zinc to zinc oxide as opposed to a slow cooling rate (250 K/s). SEM analysis found evidence of heterogeneous growth of ZnO as well as of homogeneous formation of metallic zinc. The homogeneous nucleation model fit well with experiments where only metallic zinc deposited. An expanded model with rates of oxidation by CO 2 and H 2 O as shown was combined with the homogenous nucleation model and then compared with experimental data. The calculated results based on the model gave a reasonable fit to the measured data. For the conditions used in this study, the rate equations for the oxidation of zinc by

Shallow gas charged sediments off the Indian west coast: Genesis and distribution

Digital Repository Service at National Institute of Oceanography (India)

Mazumdar, A.; Peketi, A.; Dewangan, P.; Badesab, F.K.; Ramprasad, T; Ramana, M.V.; Patil, D.J.; Dayal, A.M.

Geophysical and geochemical surveys were carried out off Goa, central west coast of India, to understand the genesis and distribution of shallow gases in marine sediments. Shallow gas charged sediments within the water depths of approx. 15 to 40 m...

Dynamic Stability Study of Static Gas Bearing for Small Cryogenic Turbo-Expander

International Nuclear Information System (INIS)

Wang Xuemin; Zhuang Ming; Zhang Qiyong; Li Shanshan; Fu Bao

2011-01-01

An experimental method is presented to analyze the dynamic stability of the gas bearing for small cryogenic turbo-expanders. The rotation imbalance response and the shape of the rotor orbit were obtained for different speeds up to 110,000 rpm, and the critical speed of the rotor-bearing system was determined by a Bode diagram. An FFT signal analytical method was applied to identify the resonance frequency, and the waterfall plot was presented. During the whole process of speeding up to the designed speed of 110,000 rpm, the rotor-bearing works stably with no whirl instability, which is validated in a waterfall plot. Also, the tested rotor-bearing model was analyzed theoretically. It was proved that the experimental results were highly consistent with those of theoretical calculations. Thus the experimental method proposed here to analyze the dynamic stability of the gas bearing is feasible. (fusion engineering)

Laboratory Optimization Tests of Decontamination of Cs, Sr, and Actinides from Hanford Waste Treatment Plant Low Activity Waste Off-Gas Condensate Simulant

Energy Technology Data Exchange (ETDEWEB)

Taylor-Pashow, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Nash, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); McCabe, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-01-06

The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream (LAW Off-Gas Condensate) from the off-gas system. The baseline plan for disposition of this stream is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility. Alternate disposition of this stream would eliminate recycling of problematic components, and would enable less integrated operation of the LAW melter and the Pretreatment Facilities. Eliminating this stream from recycling within WTP would also substantially decrease the LAW vitrification mission duration and quantity of glass waste.

Coupled Thermo-Hydro-Mechanical-Chemical Modeling of Water Leak-Off Process during Hydraulic Fracturing in Shale Gas Reservoirs

Directory of Open Access Journals (Sweden)

Fei Wang

2017-11-01

Full Text Available The water leak-off during hydraulic fracturing in shale gas reservoirs is a complicated transport behavior involving thermal (T, hydrodynamic (H, mechanical (M and chemical (C processes. Although many leak-off models have been published, none of the models fully coupled the transient fluid flow modeling with heat transfer, chemical-potential equilibrium and natural-fracture dilation phenomena. In this paper, a coupled thermo-hydro-mechanical-chemical (THMC model based on non-equilibrium thermodynamics, hydrodynamics, thermo-poroelastic rock mechanics, and non-isothermal chemical-potential equations is presented to simulate the water leak-off process in shale gas reservoirs. The THMC model takes into account a triple-porosity medium, which includes hydraulic fractures, natural fractures and shale matrix. The leak-off simulation with the THMC model involves all the important processes in this triple-porosity medium, including: (1 water transport driven by hydraulic, capillary, chemical and thermal osmotic convections; (2 gas transport induced by both hydraulic pressure driven convection and adsorption; (3 heat transport driven by thermal convection and conduction; and (4 natural-fracture dilation considered as a thermo-poroelastic rock deformation. The fluid and heat transport, coupled with rock deformation, are described by a set of partial differential equations resulting from the conservation of mass, momentum, and energy. The semi-implicit finite-difference algorithm is proposed to solve these equations. The evolution of pressure, temperature, saturation and salinity profiles of hydraulic fractures, natural fractures and matrix is calculated, revealing the multi-field coupled water leak-off process in shale gas reservoirs. The influences of hydraulic pressure, natural-fracture dilation, chemical osmosis and thermal osmosis on water leak-off are investigated. Results from this study are expected to provide a better understanding of the

A laser-based sensor for measurement of off-gas composition and temperature in basic oxygen steelmaking

International Nuclear Information System (INIS)

Ottesen, D.; Allendorf, S.; Ludowise, P.; Hardesty, D.; Miller, T.; Goldstein, D.; Smith, C.; Bonin, M.

1999-01-01

We are developing an optical sensor for process control in basic oxygen steelmaking. The sensor measures gas temperature and relative CO/CO 2 concentration ratios in the furnace off-gas by transmitting the laser probe beam directly above the furnace lip and below the exhaust hood during oxygen blowing. Dynamic off-gas information is being evaluated for optimizing variables such as lance height, oxygen flow, post-combustion control, and prediction of final melt-carbon content. The non-invasive nature of the optical sensor renders it robust and relatively maintenance-free. Additional potential applications of the method are process control for electric arc furnace and bottom-blown oxygen steelmaking processes. (author)

System Design Description and Requirements for Modeling the Off-Gas Systems for Fuel Recycling Facilities

Energy Technology Data Exchange (ETDEWEB)

Daryl R. Haefner; Jack D. Law; Troy J. Tranter

2010-08-01

This document provides descriptions of the off-gases evolved during spent nuclear fuel processing and the systems used to capture the gases of concern. Two reprocessing techniques are discussed, namely aqueous separations and electrochemical (pyrochemical) processing. The unit operations associated with each process are described in enough detail so that computer models to mimic their behavior can be developed. The document also lists the general requirements for the desired computer models.

Pilot plant development for adsorptive krypton separation from dissolver off-gas

International Nuclear Information System (INIS)

Ringel, H.; Printz, R.

1987-01-01

In view of hot cell application a separation process was investigated for the retention of Kr-85 from gaseous effluents. In the flow sheet only adsorption beds are applied. The most efficient process scheme is adsorption of the noble gas on activated charcoal and thereafter separation of the coadsorbed gas species like N 2 , O 2 , Xe and CO 2 from the krypton by gas chromatography. Adsorption is at normal pressure and low temperatures of up to -160 0 C, whereas desorption is at elevated temperatures and under helium purge. Influences on the process operation like off-gas composition, adsorption temperatures and adsorbent are experimentally investigated, as well as the behavior of trace impurities in the adsorption columns. On the basis of pilot plant operation the main components for a full scale facility are being designed

Gas turbine control for islanding operation of distribution systems

DEFF Research Database (Denmark)

Mahat, Pukar; Chen, Zhe; Bak-Jensen, Birgitte

2009-01-01

Danish distribution systems are characterized by a significant penetration of small gas turbine generators (GTGs) and fixed speed wind turbine generators (WTGs). Island operation of these distribution systems are becoming a viable option for economical and technical reasons. However, stabilizing...... frequency in an islanded system is one of the major challenges. This paper presents three different gas turbine governors for possible operation of distribution systems in an islanding mode. Simulation results are presented to show the performance of these governors in grid connected and islanding mode....

H_2 production by the steam reforming of excess boil off gas on LNG vessels

International Nuclear Information System (INIS)

Fernández, Ignacio Arias; Gómez, Manuel Romero; Gómez, Javier Romero; López-González, Luis M.

2017-01-01

Highlights: • BOG excess in LNG vessels is burned in the GCU without energy use. • The gas management plants need to be improved to increase efficiency. • BOG excess in LNG vessels is used for H_2 production by steam reforming. • The availability of different fuels increases the versatility of the ship. - Abstract: The gas management system onboard LNG (Liquid Natural Gas) vessels is crucial, since the exploitation of the BOG (Boil Off Gas) produced is of utmost importance for the overall efficiency of the plant. At present, LNG ships with no reliquefaction plant consume the BOG generated in the engines, and the excess is burned in the GCU (Gas Combustion Unit) without any energy use. The need to improve the gas management system, therefore, is evident. This paper proposes hydrogen production through a steam reforming plant, using the excess BOG as raw material and thus avoiding it being burned in the GCU. To test the feasibility of integrating the plant, an actual study of the gas management process on an LNG vessel with 4SDF (4 Stroke Dual Fuel) propulsion and with no reliquefaction plant was conducted, along with a thermodynamic simulation of the reforming plant. With the proposed gas management system, the vessel disposes of different fuels, including H_2, a clean fuel with zero ozone-depleting emissions. The availability of H_2 on board in areas with strict anti-pollution regulations, such as ECAs (Emission Control Area), means that the vessel may be navigated without using fossil fuels which generate CO_2 and SO_X emissions. Moreover, while at port, Cold Ironing is avoided, which entails high costs. Thus it is demonstrated that the installation of a reforming plant is both energetically viable and provides greater versatility to the ship.

Stability of mutualisms in a lattice gas system of two species

Directory of Open Access Journals (Sweden)

Yuanshi Wang

2015-01-01

Full Text Available This article considers mutualisms in a lattice gas system of two species. The species are mutualistic since each one can provide resources to the other. They are also competitive since they compete for empty sites on the same lattice. The mutualisms are assumed to have a saturated response, and the intraspecific competition is considered because of self-limitation. The mutualism system is characterized by differential equations, which are derived from reactions on lattice and are extension of a previous model. Global stability analysis demonstrates that (i When neither species can survive alone, they can coexist if mutualisms between them are strong and population densities are large, which exhibits the Allee effect in obligate mutualism; (ii When one species can survive alone but the other cannot, the latter one will survive if the mutualistic effect from the former is strong. Even if the effect is intermediate, the latter species can survive by strengthening its mutualistic effect on the former and enhancing its population density; (iii When either species can survive alone, a weak mutualism will lead to extinction of one species. When in coexistence, intermediate strength of mutualism is shown to be beneficial under certain parameter range, while over- or under- mutualism is not good. Furthermore, extremely strong/weak mutualism is exhibited to result in extinction of one/both species. While seven typical dynamics are displayed by numerical simulation in a previous work, they are proved in this work and the eighth one is exhibited. Numerical simul ations validate and extend our conclusions.

Experimental study of flame stability in biogas premix system

International Nuclear Information System (INIS)

Diaz G, Carlos A; Amell A Andres; Cardona Luis F

2008-01-01

Utilization of new renewable energy sources have had a special interest in last years looking for decrease the dependence of fossil fuels and the environmental impact generated for them. This work studies experimentally the flame stability of a simulated biogas with a volumetric composition of 60% methane and 40% carbon dioxide. The objective of this study is to obtain information about design and interchangeability of gases in premixed combustion systems that operate with different fuel gases. The critical velocity gradient was the stability criteria used. Utilization of this criteria and the experimental method followed, using a partial premixed burner, stability flame diagram of biogas studied had been obtained. Presence of carbon dioxide has a negative effect in flame stability, decreasing significantly the laminar flame speed and consequently, the stability range of biogas burners because of apparition of blow off.

Influence of Pilot Flame Parameters on the Stability of Turbulent Jet Flames

KAUST Repository

Guiberti, Thibault F.

2016-11-08

This paper presents a comprehensive study of the effects of pilot parameters on flame stability in a turbulent jet flame. The Sydney inhomogeneous piloted burner is employed as the experimental platform with two main fuels, namely, compressed natural gas and liquefied petroleum gas. Various concentrations of five gases are used in the pilot stream, hydrogen, acetylene, oxygen, nitrogen, and argon, to enable a sufficient range in exploring the following parameters: pilot heat release, temperature, burnt gas velocity, equivalence ratio, and H/C ratio. The experimental results are mainly presented in the form of blow-off limits and supported by simple calculations, which simulate various conditions of the pilot–mixture interface. It is found that increasing the pilot adiabatic flame temperature benefits the flame stability and has an even greater influence than the heat release, which is also known to enhance the blow-off limits. Conversely, increasing the pilot burnt gas velocity reduces the blow-off velocity, except for the limiting case when the jet is fully non-premixed. The H/C ratio has negligible effects, while resorting to lean pilots significantly increases the stability of globally rich partially premixed and premixed jets. Such findings are consistent with trends obtained from laminar flame calculations for rich fuel/air mixtures issuing against hot combustion products to simulate the pilot stream.

Development of realtime disaster mitigation system for urban gas supply network

Energy Technology Data Exchange (ETDEWEB)

Shimizu, Y.; Koganemaru, K.; Nakayama, W. [Technology Research Inst., Tokyo Gas Co. Ltd., Tokyo (Japan); Yamazaki, F. [Chiba University, Chiba (Japan); Isoyama, R.; Ishida, E. [Japan Engineering Consultants Co. Ltd., Tokyo (Japan)

2004-07-01

In response to the Kobe earthquake in 1995, efforts were initiated to develop a real-time system to mitigate earthquake-induced damages in gas supply networks which aimed at collecting information quickly and, if necessary, carrying out emergency measures. A new compact seismograph was recently developed, entitled New SI Sensor (SI). This device houses an electronic circuit which determines the SI value more precisely, detects the onset of liquefaction, and transmits the whole time history of seismic acceleration to head quarters. Consequently, a new safety system called SUPer-dense REaltime Monitoring of Earthquake (SUPREME) was developed which makes use of 3,800 new SI sensors. This paper introduces the structure of this new system. The remote shut-off using SUPREME results in quick gas supply shut-off and effectively reduce the risk of gas leakage during earthquakes. With enhanced use of geographic information systems, SUPREME can also conduct damage assessment for gas pipelines. To estimate the distribution of SI values and liquefied depth more precisely, digital map, geological map, topographical map and borehole logging data of about 60,000 sites were collected and compiled. Site amplification factors for SI values were estimated at the boring points. Then, spatial distribution of the site amplification factor was estimated based on weighted average of the amplification factors of surrounding boring points and the geological and topographical maps. 9 refs., 2 tabs., 14 figs.

Design Of Vertical Take-Off And Landing VTOL Aircraft System

Directory of Open Access Journals (Sweden)

Win Ko Ko Oo

2017-04-01

Full Text Available Vertical Take Off and Landing Vehicles VTOL are the ones which can take off and land from the same place without need of long runway. This paper presents the design and implementation of tricopter mode and aircraft mode for VTOL aircraft system. Firstly the aircraft design is considered for VTOL mode. And then the mathematical model of the VTOL aircraft is applied to test stability. In this research the KK 2.1 flight controller is used for VTOL mode and aircraft mode. The first part is to develop the VTOL mode and the next part is the transition of VTOL mode to aircraft mode. This paper gives brief idea about numerous types of VTOLs and their advantages over traditional aircraftsand insight to various types of tricopter and evaluates their configurations.

Iodine Pathways and Off-Gas Stream Characteristics for Aqueous Reprocessing Plants – A Literature Survey and Assessment

Energy Technology Data Exchange (ETDEWEB)

R. T. Jubin; D. M. Strachan; N. R. Soelberg

2013-09-01

Used nuclear fuel is currently being reprocessed in only a few countries, notably France, England, Japan, and Russia. The need to control emissions of the gaseous radionuclides to the air during nuclear fuel reprocessing has already been reported for the entire plant. But since the gaseous radionuclides can partition to various different reprocessing off-gas streams, for example, from the head end, dissolver, vessel, cell, and melter, an understanding of each of these streams is critical. These off-gas streams have different flow rates and compositions and could have different gaseous radionuclide control requirements, depending on how the gaseous radionuclides partition. This report reviews the available literature to summarize specific engineering data on the flow rates, forms of the volatile radionuclides in off-gas streams, distributions of these radionuclides in these streams, and temperatures of these streams. This document contains an extensive bibliography of the information contained in the open literature.

Experimental engineering section off-gas decontamination facility's fractionator column: installation and performance

International Nuclear Information System (INIS)

Gilliam, T.M.; Fowler, V.L.; Inman, D.J.

1978-03-01

A detailed description of the third column recently installed in the Experimental Engineering Section Off-Gas Decontamination Facility (EES-ODF) is presented. The EES-ODF is being used to provide engineering-scale experiments (nominal gas and liquid flows of 5 scfm and 0.5 gpm, respectively) in the development of the Krypton Absorption in Liquid CO 2 (KALC) process. A detailed discussion of the column's construction is provided. This discussion includes the peripherals associated with the column, such as refrigeration, heat exchangers, instrumentation, etc. The compressibility of Goodloe packing (the packing in the other columns) and the possible reduced throughput due to this compression have revealed the desirablility of a random (i.e., noncompressible) packing. Toward this end, the third column is packed with a new random packing (PRO-PAK). A preliminary comparison between this packing and the woven wire mesh packing (Goodloe) used in the other two columns has been made. Experiments comparing the throughput capacity indicate that the PRO-PAK packing has approximately 60% the capacity of Goodloe for a CO 2 system. When used as a fractionator or stripper with the basic O 2 -Kr-CO 2 KALC system, the PRO-PAK column produced HTU values less than or equal to the GOODLOE columns under similar operating conditions

Data quality objectives summary report for the 105-N monolith off-gas issue

International Nuclear Information System (INIS)

Pisarcik, D.J.

1997-01-01

The 105-N Basin hardware waste with radiation exposure rates high enough to make above-water handling and packaging impractical has been designated high exposure rate hardware (HERH) waste. This material, consisting primarily of irradiated reactor components, is packaged underwater for subsequent disposal as a grout-encapsulated solid monolith. The third HERH waste package that was created (Monolith No. 3) was not immediately removed from the basin because of administrative delays. During a routine facility walkdown, Monolith No. 3 was observed to be emitting bubbles. Mass spectroscopic analysis of a gas sample from Monolith No. 3 indicated that the gas was 85.2% hydrogen along with a trace of fission gases (stable isotopes of xenon). Gamma energy analysis of a gas sample from Monolith No. 3 also identified trace quantities of 85 Kr. The monolith off-gas Data Quality Objective (DQO) process concluded the following: Monolith No. 3 and similar monoliths can be safely transported following installation of spacers between the lids of the L3-181 transport cask to vent the hydrogen gas; The 85 Kr does not challenge personnel or environmental safety; Fumaroles in the surface of gassing monoliths renders them incompatible with Hanford Site Solid Waste Acceptance Criteria requirements unless placed in a qualified high integrity container overpack; and Gassing monoliths do meet Environmental Restoration Disposal Facility Waste Acceptance Criteria requirements. This DQO Summary Report is both an account of the Monolith Off-Gas DQO Process and a means of documenting the concurrence of each of the stakeholder organizations

Design and operation of off-gas cleaning and ventilation systems in facilities handling low and intermediate level radioactive material

International Nuclear Information System (INIS)

1988-01-01

The number of developing countries constructing new nuclear facilities is increasing. These facilities include the production and processing of radioisotopes, as well as all types of laboratories and installations, which handle radioactive material and deal with the treatment of radioactive wastes. Ventilation and air cleaning systems are a vital part of the general design of any nuclear facility. The combination of a well designed ventilation system with thorough cleaning of exhaust air is the main method of preventing radioactive contamination of the air in working areas and in the surrounding atmosphere. This report provides the latest information on the design and operation of off-gas cleaning and ventilation systems for designers and regulatory authorities in the control and operation of such systems in nuclear establishments. The report presents the findings of an Advisory Group Meeting held in Vienna from 1 to 5 December 1986 and attended by 12 experts from 11 Member States. Following this meeting, a revised report was prepared by the International Atomic Energy Agency Secretariat and three consultants, M.J. Kabat (Canada), W. Stotz (Federal Republic of Germany) and W.A. Fairhurst (United Kingdom). The final draft was commented upon and approved by the participants of the meeting. 69 refs, 37 figs, 12 tabs

Integrated Wavelength-Tunable Light Source for Optical Gas Sensing Systems

Directory of Open Access Journals (Sweden)

Bin Li

2015-01-01

Full Text Available A compact instrument consisting of a distributed feedback laser (DFB at 1.65 μm was developed as a light source for gas sensing systems using tunable diode laser absorption spectroscopy (TDLAS technique. The wavelength of laser is tuned by adjusting the laser working temperature and injection current, which are performed by self-developed temperature controller and current modulator respectively. Stability test shows the fluctuation of the laser temperature is within the range of ±0.02°C. For gas detection experiments, the wavelength is tuned around the gas absorption line by adjusting laser temperature and is then shifted periodically to scan across the absorption line by the laser current modulator, which generates a 10 Hz saw wave signal. In addition, the current modulator is able to generate sine wave signal for gas sensing systems using wavelength modulation spectroscopy (WMS technique involving extraction of harmonic signals. The spectrum test proves good stability that the spectrum was measured 6 times every 10 minutes at the constant temperature and current condition. This standalone instrument can be applied as a light source for detection systems of different gases by integrating lasers at corresponding wavelength.

Treatment of the off-gas stream from the HTR reprocessing head-end

International Nuclear Information System (INIS)

Barnert-Wiemer, H.; Juergens, B.; Vijgen, H.

1985-01-01

The AKUT II-facility (nominal throughput 10 m 3 /h, STP) for the clean-up of the burner off-gas has been operated for 20 cold runs in parallel to the JUPITER reprocessing head-end. Two of these runs were continuous operation tests with a duration of 50 and 80 hours, respectively. The facility met or exceeded all design specifications. In a further test series the distillation column alone was run with pure CO 2 and two- and three-component gas mixtures to determine the flooding curves and the stage height (HETP)

The gas-hydrate-related seabed features in the Palm Ridge off southwest Taiwan

Science.gov (United States)

Su, Zheng-Wei; Hsu, Shu-Kun; Tsai, Ching-Hui; Chen, Song-Chuen; Lin, Hsiao-Shan

2016-04-01

The offshore area of the SW Taiwan is located in the convergence zone between the northern continental margin of the South China Sea and the Manila subduction complex. Our study area, the Palm Ridge, is located in the passive continental margin. According to the geophysical, geochemical and geothermal data, abundant gas hydrate may exist in the offshore area of SW Taiwan. In this study, we will study the relation between the seabed features and the gas hydrate formation of the Palm Ridge. The data used in this study include high-resolution sidescan sonar images, sub-bottom profiles, echo sounder system, multi-beam bathymetric data, multi-channel reflection seismic and submarine photography in the Palm Ridge. Our results show the existing authigenic carbonates, gas seepages and gas plumes are mainly distributed in the bathymetric high of the Palm Ridge. Numerous submarine landslides have occurred in the place where the BSR distribution is not continuous. We suggest that it may be because of rapid slope failure, causing the change of the gas hydrate stability zone. We also found several faults on the R3.1 anticline structure east of the deformation front. These features imply that abundant deep methane gases have migrated to shallow strata, causing submarine landslides or collapse. The detailed relationship of gas migration and submarine landslides need further studies.

Determination of Reasons of Obstruction in the Condensate Stabilizer System of Namconson Gas Treatment Terminal by Radioisotope Techniques

International Nuclear Information System (INIS)

Bui Quang Tri; Nguyen Huu Quang; Dang Nguyen The Duy; Tran Tri Hai; Tran Thanh Minh

2008-01-01

The Condensate Stabilizer System of Namconson Gas Treatment Terminal was designed with operational flow rate of 60 m 3 /h but for unknown reason it ran efficiently below 20 m 3 /h. The Radiotracer in combination with Gamma Scan was used to investigate in understanding the reasons. The results showed the build up at the bottom of Trap out Tray which caused obstruction of condensate flow in the outlet of Trap out Tray. As a results the feed flow rate to Reboiler from Trap out Tray lowered into 1/3 and the remaining 2/3 by passing the Reboiler by overflow to the Sump. (author)

Effectiveness of the Vertical Gas Ventilation Pipes for Promoting Waste Stabilization in Post-Closure Phase

Directory of Open Access Journals (Sweden)

Yasumasa Tojo

2015-06-01

Full Text Available To make inside of the municipal solid waste (MSW landfill aerobic as much as possible is thought to be preferable for promoting waste stabilization, reducing pollutant's load in leachate, minimizing greenhouse gas emission and shortening post-closure-care period. In Japan, installation of semi-aerobic landfill structure has widely spread in order to promote waste stabilization in MSW landfill from 1980s. In semi-aerobic landfill structure, outlet of main leachate collection pipe is opened to atmosphere. Heat generated by aerobic degradation of waste causes natural convection and natural aeration arises from the outlet of leachate collection pipe to the gas vents. It is so-called stack effect. This air flow is thought to be effective for purifying leachate flowing through drainage layer and leachate collection pipes. And it is also thought to be contributing to expanding aerobic region in waste layer in landfill. Recently, measures attempting the promotion of waste stabilization are taken at several landfills at where stabilization of waste delays, in which many vertical gas vents are newly installed and close structure to semi-aerobic landfill is created. However, in many cases, these gas vents are not connected to leachate collection pipes. Many vertical gas vents are just installed without scientific proof regarding whether they can contribute for waste stabilization. In this study, how such installation of gas vents is effective for waste stabilization and aerobization of waste layer was discussed by numerical analysis. In numerical analysis, heat transfer, gas movement by pressure, gas diffusion, biological degradation of organic matter, and heat generation by biodegradation were taken into account. Simulations were carried out by using the general purpose simulator of finite element method. Three types of landfill structure were assumed. As the results, the following information were obtained. In dig-down type landfill, installation of gas

Air ionization as a control technology for off-gas emissions of volatile organic compounds.

Science.gov (United States)

Kim, Ki-Hyun; Szulejko, Jan E; Kumar, Pawan; Kwon, Eilhann E; Adelodun, Adedeji A; Reddy, Police Anil Kumar

2017-06-01

High energy electron-impact ionizers have found applications mainly in industry to reduce off-gas emissions from waste gas streams at low cost and high efficiency because of their ability to oxidize many airborne organic pollutants (e.g., volatile organic compounds (VOCs)) to CO 2 and H 2 O. Applications of air ionizers in indoor air quality management are limited due to poor removal efficiency and production of noxious side products, e.g., ozone (O 3 ). In this paper, we provide a critical evaluation of the pollutant removal performance of air ionizing system through comprehensive review of the literature. In particular, we focus on removal of VOCs and odorants. We also discuss the generation of unwanted air ionization byproducts such as O 3 , NOx, and VOC oxidation intermediates that limit the use of air-ionizers in indoor air quality management. Copyright © 2017. Published by Elsevier Ltd.

Off-Line Robust Constrained MPC for Linear Time-Varying Systems with Persistent Disturbances

Directory of Open Access Journals (Sweden)

P. Bumroongsri

2014-01-01

Full Text Available An off-line robust constrained model predictive control (MPC algorithm for linear time-varying (LTV systems is developed. A novel feature is the fact that both model uncertainty and bounded additive disturbance are explicitly taken into account in the off-line formulation of MPC. In order to reduce the on-line computational burdens, a sequence of explicit control laws corresponding to a sequence of positively invariant sets is computed off-line. At each sampling time, the smallest positively invariant set containing the measured state is determined and the corresponding control law is implemented in the process. The proposed MPC algorithm can guarantee robust stability while ensuring the satisfaction of input and output constraints. The effectiveness of the proposed MPC algorithm is illustrated by two examples.

Off-design dynamic model of a real Organic Rankine Cycle system fuelled by exhaust gases from industrial processes

International Nuclear Information System (INIS)

Mazzi, N.; Rech, S.; Lazzaretto, A.

2015-01-01

ORCs (Organic Rankine Cycles) represent an effective option to exploit low grade heat fluxes, the characteristics of which not only affect design, but also performance and stability during operation. This paper presents a detailed design and off-design dynamic model of a superheated regenerative ORC system using the exhaust gases of an industrial process. The point of view is that of a designer who has to predict the system behavior both at steady-state and transient operation to get a reliable and efficient operation. Real physical and operating characteristics of all components are considered, with particular attention to the geometries of shell-and-tube commercial heat exchangers to properly simulate mass and thermal inertias. A suitable control system is chosen to govern the off-design operation taking into account all real operating constraints. Results show a slight decrease in gross system efficiency (less than 1% point) either varying the oil mass flow rate (in the range 80–110%) at constant temperature of the cold sink or this temperature (of 10 °C) at constant oil mass flow rate. Simulation of the transient behavior demonstrates the effectiveness of the control system on ORC stability under variation of the hot source mass flow rate and cold sink temperature. - Highlights: • A detailed off-design dynamic model of a regenerative ORC system is presented. • The model includes real geometries of commercial shell-and-tube heat exchangers. • High efficiency of the ORC system is obtained at partial load in the range 80–110%. • Variations of the evaporator volume does not significantly affect system stability.

Stability and suppression of turbulence in relaxing molecular gas flows

CERN Document Server

Grigoryev, Yurii N

2017-01-01

This book presents an in-depth systematic investigation of a dissipative effect which manifests itself as the growth of hydrodynamic stability and suppression of turbulence in relaxing molecular gas flows. The work describes the theoretical foundations of a new way to control stability and laminar turbulent transitions in aerodynamic flows. It develops hydrodynamic models for describing thermal nonequilibrium gas flows which allow the consideration of suppression of inviscid acoustic waves in 2D shear flows. Then, nonlinear evolution of large-scale vortices and Kelvin-Helmholtz waves in relaxing shear flows are studied. Critical Reynolds numbers in supersonic Couette flows are calculated analytically and numerically within the framework of both linear and nonlinear classical energy hydrodynamic stability theories. The calculations clearly show that the relaxation process can appreciably delay the laminar-turbulent transition. The aim of the book is to show the new dissipative effect, which can be used for flo...

Basin-Wide Temperature Constraints On Gas Hydrate Stability In The Gulf Of Mexico

Science.gov (United States)

MacDonald, I. R.; Reagan, M. T.; Guinasso, N. L.; Garcia-Pineda, O. G.

2012-12-01

Gas hydrate deposits commonly occur at the seafloor-water interface on marine margins. They are especially prevalent in the Gulf of Mexico where they are associated with natural oil seeps. The stability of these deposits is potentially challenged by fluctuations in bottom water temperature, on an annual time-scale, and under the long-term influence of climate change. We mapped the locations of natural oil seeps where shallow gas hydrate deposits are known to occur across the entire Gulf of Mexico basin based on a comprehensive review of synthetic aperture radar (SAR) data (~200 images). We prepared a bottom water temperature map based on the archive of CTD casts from the Gulf (~6000 records). Comparing the distribution of gas hydrate deposits with predicted bottom water temperature, we find that a broad area of the upper slope lies above the theoretical stability horizon for structure 1 gas hydrate, while all sites where gas hydrate deposits occur are within the stability horizon for structure 2 gas hydrate. This is consistent with analytical results that structure 2 gas hydrates predominate on the upper slope (Klapp et al., 2010), where bottom water temperatures fluctuate over a 7 to 10 C range (approx. 600 m depth), while pure structure 1 hydrates are found at greater depths (approx. 3000 m). Where higher hydrocarbon gases are available, formation of structure 2 gas hydrate should significantly increase the resistance of shallow gas hydrate deposits to destabilizing effects variable or increasing bottom water temperature. Klapp, S.A., Bohrmann, G., Kuhs, W.F., Murshed, M.M., Pape, T., Klein, H., Techmer, K.S., Heeschen, K.U., and Abegg, F., 2010, Microstructures of structure I and II gas hydrates from the Gulf of Mexico: Marine and Petroleum Geology, v. 27, p. 116-125.Bottom temperature and pressure for Gulf of Mexico gas hydrate outcrops and stability horizons for sI and sII hydrate.

LABORATORY OPTIMIZATION TESTS OF TECHNETIUM DECONTAMINATION OF HANFORD WASTE TREATMENT PLANT LOW ACTIVITY WASTE OFF-GAS CONDENSATE SIMULANT

Energy Technology Data Exchange (ETDEWEB)

Taylor-Pashow, K.; Nash, C.; McCabe, D.

2014-09-29

The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream (LAW Off-Gas Condensate) from the off-gas system. The baseline plan for disposition of this stream is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility again. Alternate disposition of this stream would eliminate recycling of problematic components, and would enable de-coupled operation of the LAW melter and the Pretreatment Facilities. Eliminating this stream from recycling within WTP would also decrease the LAW vitrification mission duration and quantity of glass waste. This LAW Off-Gas Condensate stream contains components that are volatile at melter temperatures and are problematic for the glass waste form. Because this stream recycles within WTP, these components accumulate in the Condensate stream, exacerbating their impact on the number of LAW glass containers that must be produced. Approximately 32% of the sodium in Supplemental LAW comes from glass formers used to make the extra glass to dilute the halides to acceptable concentrations in the LAW glass, and diverting the stream reduces the halides in the recycled Condensate and is a key outcome of this work. Additionally, under possible scenarios where the LAW vitrification facility commences operation prior to the WTP Pretreatment facility, identifying a disposition path becomes vitally important. This task examines the potential treatment of this stream to remove radionuclides and subsequently disposition the decontaminated stream elsewhere, such as the Effluent Treatment Facility (ETF), for example. The treatment process envisioned is very similar to that used for the Actinide Removal Process (ARP) that has been operating for years at the Savannah River Site (SRS), and focuses on using mature radionuclide removal technologies that are also

Bench scale experiments for the remediation of Hanford Waste Treatment Plant low activity waste melter off-gas condensate

Energy Technology Data Exchange (ETDEWEB)

Taylor-Pashow, Kathryn M.L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Poirier, Michael [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); McCabe, Daniel J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-08-11

The Low Activity Waste (LAW) vitrification facility at the Hanford Waste Treatment and Immobilization Plant (WTP) will generate an aqueous condensate recycle stream (LAW Off-Gas Condensate) from the off-gas system. The plan for disposition of this stream during baseline operations is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility again. The primary reason to recycle this stream is so that the semi-volatile 99Tc isotope eventually becomes incorporated into the glass. This stream also contains non-radioactive salt components that are problematic in the melter, so diversion of this stream to another process would eliminate recycling of these salts and would enable simplified operation of the LAW melter and the Pretreatment Facilities. This diversion from recycling this stream within WTP would have the effect of decreasing the LAW vitrification mission duration and quantity of glass waste. The concept being tested here involves removing the ⁹⁹Tc so that the decontaminated aqueous stream, with the problematic salts, can be disposed elsewhere.

Critique of Hanford Waste Vitrification Plant off-gas sampling requirements

International Nuclear Information System (INIS)

Goles, R.W.

1996-03-01

Off-gas sampling and monitoring activities needed to support operations safety, process control, waste form qualification, and environmental protection requirements of the Hanford Waste Vitrification Plant (HWVP) have been evaluated. The locations of necessary sampling sites have been identified on the basis of plant requirements, and the applicability of Defense Waste Processing Facility (DWPF) reference sampling equipment to these HWVP requirements has been assessed for all sampling sites. Equipment deficiencies, if present, have been described and the bases for modifications and/or alternative approaches have been developed

Linear stability analysis of the gas injection augmented natural circulation of STAR-LM

International Nuclear Information System (INIS)

Yeon-Jong Yoo; Qiao Wu; James J Sienicki

2005-01-01

Full text of publication follows: A linear stability analysis has been performed for the gas injection augmented natural circulation of the Secure Transportable Autonomous Reactor - Liquid Metal (STAR-LM). Natural circulation is of great interest for the development of Generation-IV nuclear energy systems due to its vital role in the area of passive safety and reliability. One of such systems is STAR-LM under development by Argonne National Laboratory. STAR-LM is a 400 MWt class modular, proliferation-resistant, and passively safe liquid metal-cooled fast reactor system that uses inert lead (Pb) coolant and the advanced power conversion system that consists of a gas turbine Brayton cycle utilizing supercritical carbon dioxide (CO 2 ) to obtain higher plant efficiency. The primary loop of STAR-LM relies only on the natural circulation to eliminate the use of circulation pumps for passive safety consideration. To enhance the natural circulation of the primary coolant, STAR-LM optionally incorporates the additional driving force provided by the injection of noncondensable gas into the primary coolant above the reactor core, which is effective in removing heat from the core and transferring it to the secondary working fluid without the attainment of excessive coolant temperature at nominal operating power. Therefore, it naturally raises the concern about the natural circulation instability due to the relatively high temperature change in the core and the two-phase flow condition in the hot leg above the core. For the ease of analysis, the flow path of the loop was partitioned into five thermal-hydraulically distinct sections, i.e., heated core, unheated core, hot leg, heat exchanger, and cold leg. The one-dimensional single-phase flow field equations governing the natural circulation, i.e., continuity, momentum, and energy equations, were used for each section except the hot leg. For the hot leg, the one-dimensional homogeneous equilibrium two-phase flow field

Gas gain stability of MSGCs on borosilicate glass

International Nuclear Information System (INIS)

Berg, F.D. van den; Daum, C.; Eijk, B. van; Hartjes, F.G.; Udo, F.; Zhukov, V.

1996-01-01

The gas gain stability in Micro Strip Gas Counters fabricated on borosilicate glass has been investigated for operation at high radiation fluxes up to 10 5 Hz/mm 2 in a X-ray set-up. We discuss effects of short and long term irradiation on the gain for different voltage settings and strip metalisations. The application of a high drift field and a back plane on positive potential provides good high rate operation up to 10 4 Hz/mm 2 . Ageing is observed to be strongly dependent on the stirp metalisation; gold and nickel perform better than aluminium and copper. (orig.)

Removal of 14C-contaminated CO2 from simulated LWR fuel reprocessing off-gas by utilizing the reaction between CO2 and alkaline hydroxides in either slurry or solid form

International Nuclear Information System (INIS)

Holladay, D.W.; Haag, G.L.

1979-01-01

An important consideration in the design of a LWR fuel reprocessing plant is the removal of 14 C-contaminated CO 2 from the process off-gas. The separation and fixation of essentially all the CO 2 from the simulated off-gas can be accomplished by reaction with alkaline slurries in agitated tank-type contactors. Based on efficacy for CO 2 removal, consideration of reactant cost, and stability of the carbonate product as related to long-term storage requirements, the two most promising slurry reactants for CO 2 removal from low CO 2 -content feed gases are Ca(OH) 2 and Ba(OH) 2 . The removal of 14 C-contaminated CO 2 from simulated LWR off-gases was studied as a function of both operating conditions and varying sizes of bench-scale design. Parametrically, the effects on the CO 2 removal rate of feed composition (330 ppM - 4.47% CO 2 ), impeller speed (325 to 650 rpm), superficial velocity (5 to 80 cm/min), reactants [Mg(OH) 2 , NaOH], contactor size (20.3 cm and 27.3 cm ID), and type of operation (semibatch or continuous slurry) were deterined

Effect of gas hydrates melting on seafloor slope stability

Science.gov (United States)

Sultan, N.; Cochonat, P.; Foucher, J. P.; Mienert, J.; Haflidason, H.; Sejrup, H. P.

2003-04-01

Henriet, J.-P.; Mienert, J. (Ed.): Gas hydrates: relevance to world margin stability and climate change. Geological Society Special Publication, 137. The Geological Society: London, UK, p. 267-274. Handa,Y.P., 1989. Effect of Hydrostatic Pressure and Salinity on the Stability of Gas Hydrates. J.Phys.Chem., Vol.94, p.2652-2657. Henry, P., Thomas, M.; Clennell, M.B., 1999. Formation of Natural Gas Hydrates in Marine Sediments 2. Thermodynamic Calculations of Stability Conditions in Porous Sediments,” J. Geophys. Res., 104, p. 23005. Sloan, E.D. Jr., 1998. Clathrate hydrates of natural gases. Marcel Dekker Inc., 2nd edition, New York, pp. 705. Soave G, 1972. Equilibrium

Possible gas hydrates on the Bjarmeland Platform; seismic expression and stability modelling

OpenAIRE

Løvaas, John Sverre

2016-01-01

Seismic evidence of shallow gas anomalies are prominent at Ververis Dome structure and Hoop Fault Complex in Bjarmeland Platform. Ubiquitous high amplitude anomalies at the same depth as these shallow gas anomalies infer a possible relation to gas hydrates. A wide range of fluid flow structures within the two study areas have previously been discovered and reported, and may possibly feed the base of the gas hydrate stability zone (BGHSZ) with upward migrating thermogenic gas. This thesis f...

Organic iodine removal from simulated dissolver off-gas systems utilizing silver-exchanged mordenite

International Nuclear Information System (INIS)

Jubin, R.T.

1981-01-01

The removal of methyl iodide by adsorption onto silver mordenite was studied using a simulated off-gas from the fuel dissolution step of a nuclear fuel reprocessing plant. The adsorption of methyl iodide on silver mordenite was examined for the effect of NO/sub x/, humidity, iodine concentration, filter temperature, silver loadings and filter pretreatment. The highest iodine loading achieved in these tests was 142 mg CH 3 I per g of substrate on fully exchanged zeolite, approximately the same as elemental iodine loadings. A filter using fully exchanged silver mordenite operating at 200 0 C obtained higher iodine loadings than a similar filter operating at 150 0 C. Pretreatment of the sorbent bed with hydrogen rather than dry air, at a temperature of 200 0 C, also improved the loading. Variations in the methyl iodide concentration had minimal effects on the overall loading. Filters exposed to moist air streams attained higher loadings than those in contact with dry air. Partially exchanged silver mordenite achieved higher silver utilizations than the fully exchanged material. The partially exchanged mordenite also achieved higher loadings at 200 0 C than at 250 0 C. The iodine loaded onto these beds was not stripped at 500 0 C by either 4.5% hydrogen or 100% hydrogen; however, the iodine could be removed by air at 500 0 C, and the bed could be reloaded. A study of the regeneration characteristics of fully exchanged silver mordenite indicates limited adsorbent capacity after complete removal of the iodine with 4.5% hydrogen in the regeneration gas stream at 500 0 C. The loss of adsorbent capacity is much higher for silver mordenite regenerated in a stainless steel filter housing than in a glass filter housing

AKUT: a process for the separation of aerosols, krypton, and tritium from burner off-gas in HTR-fuel reprocessing

International Nuclear Information System (INIS)

Laser, M.; Barnert-Wiemer, H.; Beaujean, H.; Merz, E.; Vygen, H.

1975-01-01

The AKUT process consists of the following process steps: (1) aerosol retention by an electrostatic separator followed by HEPA filters, (2) oxidation of CO with O 2 or reaction of excess O 2 with CO, respectively, (3) compression, (4) scrubbing and/or liquefaction, (5) separation of krypton by distillation, and (6) separation of tritiated water and iodine by adsorption or chemical reaction. Liquefied off-gas with low permanent gas content resulting from graphite burning with oxygen may be distilled at ambient temperature. Off-gas with higher permanent gas content from burning with oxygen enriched air must be processed at lower temperature. The ambient temperature flow sheet is preferable from an economic as well as safety point of view. (U.S.)

Burner and dissolver off-gas treatment in HTR fuel reprocessing

International Nuclear Information System (INIS)

Barnert-Wiemer, H.; Heidendael, M.; Kirchner, H.; Merz, E.; Schroeder, G.; Vygen, H.

1979-01-01

In the reprocessing of HTR fuel, essentially all of the gaseous fission products are released during the heat-end tratment, which includes burning of the graphite matrix and dissolving of the heavy metallic residues in THOREX reagent. Three facilities for off-gas cleaning are described, the status of the facility development and test results are reported. Hot tests with a continuous dissolver for HTR-type fuel (throughput 2 kg HM/d) with a closed helium purge loop have been carried out. Preliminary results of these experiments are reported

Mechanical Stability of Stratified Sediments along the upper continental Slope off Vesterålen, northern Norway - Insights from in situ CPTU Tests

Science.gov (United States)

Voelker, D.; Stegmann, S.; Kreiter, S.; L'Heureux, J. S.; Vanneste, M. W. B.; Baeten, N. J.; Knudsen, S.; Rise, L.; Longva, O.; Brendryen, J.; Haflidason, H.; Chand, S.; Mörz, T.; Kopf, A.

2015-12-01

High-resolution single channel-seismic data (3.5 kHz) reveal small-scale submarine landslide structures and superficial deformation features (e.g. tension cracks) along the gently dipping (3°) upper continental slope west of the Vesterålen Archipelago off northern Norway. Previous laboratory-based geotechnical studies attest that the slope is per sestable and that seismic events in an order of magnitude M5.7 may have triggered the slope sediments to fail. Here we present geotechnical in situ data (sedimentary strength, pore pressure), which were obtained with RV Poseidon in summer 2014 using the static CPTU system GOST. The CPTU system provided high-resolution geotechnical profiles of the uppermost sediments to a maximum penetration depth of ~ 20 m at six sites within the landslide features and beside them in undisturbed slope sediments as reference. The CPTU data reveal the occurrence of mechanically weaker zones (MWZ) by the drop of sedimentary strength. These zones are interbedded by coarser, more competent layers. The occurrence of sensitive fine-grained material may be responsible for the loss of strength in the deeper portion (appx. 12 to 18 m below seafloor). An 1D infinite pseudo-static stability analysis attests that the mechanically weaker zones (MWZ) correlate well with portions, where the Factor of Safety (FoS) ≤ 1 (meta-stable to unstable) indicates permanent deformation or failure in case additional dynamic load is induced by an earthquake. Thus, the mechanically weak layers can be considered as one important pre-condition for landslide activity. In conclusion, the integration of in situ CPTU data with geophysical data improves soil characterization and hence foster a better understanding of the pre-conditioning factors for slope instability at the upper continental slope off Vesterålen. Risk assessment for the present-day slope off Vesterålen is particularly crucial, because the opening of the region for offshore oil and gas exploration is

Faulting of gas-hydrate-bearing marine sediments - contribution to permeability

Science.gov (United States)

Dillon, William P.; Holbrook, W.S.; Drury, Rebecca; Gettrust, Joseph; Hutchinson, Deborah; Booth, James; Taylor, Michael

1997-01-01

Extensive faulting is observed in sediments containing high concentrations of methane hydrate off the southeastern coast of the United States. Faults that break the sea floor show evidence of both extension and shortening; mud diapirs are also present. The zone of recent faulting apparently extends from the ocean floor down to the base of gas-hydrate stability. We infer that the faulting resulted from excess pore pressure in gas trapped beneath the gas hydrate-beating layer and/or weakening and mobilization of sediments in the region just below the gas-hydrate stability zone. In addition to the zone of surface faults, we identified two buried zones of faulting, that may have similar origins. Subsurface faulted zones appear to act as gas traps.

A magnetic nanoparticle stabilized gas containing emulsion for multimodal imaging and triggered drug release.

Science.gov (United States)

Guo, Wei; Li, Diancheng; Zhu, Jia-an; Wei, Xiaohui; Men, Weiwei; Yin, Dazhi; Fan, Mingxia; Xu, Yuhong

2014-06-01

To develop a multimodal imaging guided and triggered drug delivery system based on a novel emulsion formulation composed of iron oxide nanoparticles, nanoscopic bubbles, and oil containing drugs. Iron oxide paramagnetic nanoparticles were synthesized and modified with surface conjugation of polyethylenimide (PEI) or Bovine Serum Albumin (BSA). Both particles were used to disperse and stabilize oil in water emulsions containing coumarin-6 as the model drug. Sulfur hexafluoride was introduced into the oil phase to form nanoscopic bubbles inside the emulsions. The resulted gas containing emulsions were evaluated for their magnetic resonance (MR) and ultrasound (US) imaging properties. The drug release profile triggered by ultrasound was also examined. We have successfully prepared the highly integrated multi-component emulsion system using the surface modified iron oxide nanoparticles to stabilize the interfaces. The resulted structure had distinctive MR and US imaging properties. Upon application of ultrasound waves, the gas containing emulsion would burst and encapsulated drug could be released. The integrated emulsion formulation was multifunctional with paramagnetic, sono-responsive and drug-carrying characteristics, which may have potential applications for disease diagnosis and imaging guided drug release.

Take-off Stability Characteristics of a 1/13-scale Model of the Consolidated Vultee Skate 7 Seaplane (TED No. NACA DE 338)

Science.gov (United States)

McKann, Robert; Coffee, Claude W.; Abrabian, Donald D.

1949-01-01

The take-off stability characteristics of a Consolidated Vultee Aircraft Corporation Skate 7 seaplane were determined in the Langley tank no. 2. Trim limits of stability, trim tracks, and elevator limits of stability are presented.

Final Report on Testing of Off-Gas Treatment Technologies for Abatement of Atmospheric Emissions of Chlorinated Volatile Organic Compounds

International Nuclear Information System (INIS)

Jarosch, T.R.; Haselow, J.S.; Rossabi, J.; Burdick, S.A.; Raymond, R.; Young, J.E.; Lombard, K.H.

1995-01-01

The purpose of this report is to summarize the results of the program for off-gas treatment of atmospheric emissions of chlorinated volatile organic compounds (CVOCs), in particular trichloroethylene (TCE) and perchloroethylene (PCE). This program was funded through the Department of Energy Office of Technology Development's VOC's in Non-Arid Soils Integrated Demonstration (VNID). The off-gas treatment program was initiated after testing of in-situ air stripping with horizontal wells was completed (Looney et al., 1991). That successful test expectedly produced atmospheric emissions of CVOCs that were unabated. It was decided after that test that an off-gas treatment is an integral portion of remediation of CVOC contamination in groundwater and soil but also because several technologies were being developed across the United States to mitigate CVOC emissions. A single platform for testing off-gas treatment technologies would facilitate cost effective evaluation of the emerging technologies. Another motivation for the program is that many CVOCs will be regulated under the Clean Air Act Amendments of 1990 and are already regulated by many state regulatory programs. Additionally, compounds such as TCE and PCE are pervasive subsurface environmental contaminants, and, as a result, a small improvement in terms of abatement efficiency or cost will significantly reduce CVOC discharges to the environment as well as costs to United States government and industry

Removal of I, Rn, Xe and Kr from off gas streams using PTFE membranes

Science.gov (United States)

Siemer, Darryl D.; Lewis, Leroy C.

1990-01-01

A process for removing I, R, Xe and Kr which involves the passage of the off gas stream through a tube-in-shell assembly, whereby the tubing is a PTFE membrane which permits the selective passages of the gases for removing and isolating the gases.

Laboratory Scoping Tests Of Decontamination Of Hanford Waste Treatment Plant Low Activity Waste Off-Gas Condensate Simulant

Energy Technology Data Exchange (ETDEWEB)

Taylor-Pashow, Kathryn M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Nash, Charles A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Crawford, Charles L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); McCabe, Daniel J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Wilmarth, William R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2014-01-21

The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream (LAW Off-Gas Condensate) from the off-gas system. The baseline plan for disposition of this stream is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility again. Alternate disposition of this stream would eliminate recycling of problematic components, and would enable de-coupled operation of the LAW melter and the Pretreatment Facilities. Eliminating this stream from recycling within WTP would also decrease the LAW vitrification mission duration and quantity of glass waste. This LAW Off-Gas Condensate stream contains components that are volatile at melter temperatures and are problematic for the glass waste form. Because this stream recycles within WTP, these components accumulate in the Condensate stream, exacerbating their impact on the number of LAW glass containers that must be produced. Approximately 32% of the sodium in Supplemental LAW comes from glass formers used to make the extra glass to dilute the halides to acceptable concentrations in the LAW glass, and diverting the stream reduces the halides in the recycled Condensate and is a key outcome of this work. Additionally, under possible scenarios where the LAW vitrification facility commences operation prior to the WTP Pretreatment facility, identifying a disposition path becomes vitally important. This task seeks to examine the potential treatment of this stream to remove radionuclides and subsequently disposition the decontaminated stream elsewhere, such as the Effluent Treatment Facility (ETF), for example. The treatment process envisioned is very similar to that used for the Actinide Removal Process (ARP) that has been operating for years at the Savannah River Site (SRS), and focuses on using mature radionuclide removal technologies that are also

The Air-Carbon-Water Synergies and Trade-Offs in China's Natural Gas Industry

Science.gov (United States)

Qin, Yue

China's coal-dominated energy structure is partly responsible for its domestic air pollution, local water stress, and the global climate change. Primarily to tackle the haze issue, China has been actively promoting a nationwide coal to natural gas end-use switch. My dissertation focuses on evaluating the air quality, carbon, and water impacts and their interactions in China's natural gas industry. Chapter 2 assesses the lifecycle climate performance of China's shale gas in comparison to coal based on stage-level energy consumption and methane leakage rates. I find the mean lifecycle carbon footprint of shale gas is about 30-50% lower than that of coal under both 20 year and 100 year global warming potentials (GWP20 and GWP100). However, primarily due to large uncertainties in methane leakage, the lifecycle carbon footprint of shale gas in China could be 15-60% higher than that of coal across sectors under GWP20. Chapter 3 evaluates the air quality, human health, and the climate impacts of China's coal-based synthetic natural gas (SNG) development. Based on earlier 2020 SNG production targets, I conduct an integrated assessment to identify production technologies and end-use applications that will bring as large air quality and health benefits as possible while keeping carbon penalties as small as possible. I find that, due to inefficient and uncontrolled coal combustion in households, allocating currently available SNG to the residential sector proves to be the best SNG allocation option. Chapter 4 compares the air quality, carbon, and water impacts of China's six major gas sources under three end-use substitution scenarios, which are focused on maximizing air pollutant emission reductions, CO 2 emission reductions, and water stress index (WSI)-weighted water consumption reductions, respectively. I find striking national air-carbon/water trade-offs due to SNG, which also significantly increases water demands and carbon emissions in regions already suffering from

On the stabilization of gas discharge by an hf-electric field

International Nuclear Information System (INIS)

Rakhimova, T.V.; Rakhimov, A.T.

1975-01-01

It is shown that when the bulk gas discharge is placed in an hf-electric field of sufficiently high frequency in the process of gas discharge burning there appears a long phase during which the gas ionization is inessential and the discharge burns in a recombining plasma. Such a stage may affect the stability of a gas discharge. It is shown also that at comparable values of intensities of the d.c. and hf electric fields there is a small parameter for the weakly-ionized plasma in which the relative portion of energy introduced into the discharge during the stage of gas ionization may be sufficiently small. (Auth.)

Shock structure in continuum models of gas dynamics: stability and bifurcation analysis

International Nuclear Information System (INIS)

Simić, Srboljub S

2009-01-01

The problem of shock structure in gas dynamics is analysed through a comparative study of two continuum models: the parabolic Navier–Stokes–Fourier model and the hyperbolic system of 13 moments equations modeling viscous, heat-conducting monatomic gases within the context of extended thermodynamics. When dissipative phenomena are neglected these models both reduce to classical Euler's equations of gas dynamics. The shock profile solution, assumed in the form of a planar travelling wave, reduces the problem to a system of ordinary differential equations, and equilibrium states appear to be stationary points of the system. It is shown that in both models an upstream equilibrium state suffers an exchange of stability when the shock speed crosses the critical value which coincides with the highest characteristic speed of the Euler's system. At the same time a downstream equilibrium state could be seen as a steady bifurcating solution, while the shock profile represents a heteroclinic orbit connecting the two stationary points. Using centre manifold reduction it is demonstrated that both models, although mathematically different, obey the same transcritical bifurcation pattern in the neighbourhood of the bifurcation point corresponding to the critical value of shock speed, the speed of sound

Consequence assessment of floating and storage and off loading (FPSO) systems

International Nuclear Information System (INIS)

Smith, Duncan; Alderman, John A.

2000-01-01

Floating Production, Storage and Off loading (FPSO) systems are increasingly being used for deep water fields where use of traditional platforms and pipelines is not cost effective. The risks associated with FPSOs are inherently different from those for onshore facilities and conventional offshore platforms.This paper focuses on some of the key issues in the application of consequence assessment to FPSOs. A review and illustration of some of the techniques used for analysis of hydrocarbon hazards associated with FPSO operations will be included. Examples covered include evaluation of heat fluxes from a jet fire from an ignited riser leak and evaluation of explosion overpressure from a gas release on the main deck of the FPSO using ARAMAS. The assessment of the impact of smoke inhalation to personnel taking shelter in the accommodation block of the FPSO during a large fire event is also explained. Experiences gained from consequence assessments and quantitative risk analyses performed for offshore platforms, FPSOs, Floating Storage and Off loading (FSO) systems, as well as onshore refinery and petrochemical facilities will be detailed. (author)

National Gas Hydrate Program Expedition 01 offshore India; gas hydrate systems as revealed by hydrocarbon gas geochemistry

Science.gov (United States)

Lorenson, Thomas; Collett, Timothy S.

2018-01-01

suggests a thermogenic source. Gas hydrate accumulations in the Krishna-Godavari and Mahanadi Basins are the result of a microbially sourced gas hydrate system. The system is enhanced by the migration of microbial gas from surrounding areas through pathways including high-porosity delta sands, shale diapirism, faulting and folding of sediment due to the local processes associated with rapid sediment deposition, sediment overpressure, and the recycling of methane from a rapidly upward moving gas hydrate stability zone. The gas hydrate system in the Andaman Basin is less well constrained due to lack of exploration and occurs in a forearc basin. Each of these hydrate-bearing systems overlies and is likely supported by the presence and possible migration of gas from deeper gas-prone petroleum systems currently generating thermogenic hydrocarbons at much greater depths.

Fast Turn-off Mine Transient Electromagnetic Transmitter System

Directory of Open Access Journals (Sweden)

ZHENG Xiao-Liang

2014-05-01

Full Text Available For solving problems such as short turn-off time, high linear degree of falling edge, measurement of turn-off time and influence of primary signals for transient electromagnetic transmitter, and restrictions because of the environmental conditions of underground coal mine, this thesis aims at designing a new transient electromagnetic transmitter system suitable for coal mine. Supported by damping absorption circuit, such system applies small volume, sectional transmitting coil, with features of short turn-off time, high linear degree of current falling edge. It uses the transmitter monitoring circuit, which accurately measures turn-off time and simultaneously records the current value changes after turn-off, thus to eliminate the influence of primary field as well as to restore earlier secondary field signals for reference and finally to improve the ability to detect the shallow structure. It turns out that the new system has a shorter turn-off time, a higher linear degree of current falling and more accurate data record of turn-off current.

Application of an entry-exit tariff model to the gas transport system in Spain

International Nuclear Information System (INIS)

Alonso, Alejandro; Serrano, Miguel; Olmos, Luis

2010-01-01

Under an entry-exit gas tariff system, reservation of capacity is split into entry capacity, to transport gas from the injection points to a virtual balancing point, and exit capacity, to transport gas from the balancing point to the exit points in the system. Entry-exit tariff for gas transport systems have been recommended by the 3rd EU Energy Package, since they are cost reflective, facilitate gas trade and can provide signals for the location of gas injections or off-takes. The advisability of applying an entry-exit tariff system is discussed in this paper. Apart from this, authors propose an entry-exit tariff model and apply it to compute charges for the Spanish gas transport system in 2009. Results produced by the model are presented as coefficients which should multiply the current postal transport tariff. The paper concludes that entry-exit tariffs would be useful location signals which would result in a better use of the gas transport system in Spain. In those cases where demand exceeds available capacity, as it occurs at the congested connection with France, entry-exit tariffs could be supplemented by capacity charges at entry points resulting from auctions. (author)

Pinch-off Scaling Law of Soap Bubbles

Science.gov (United States)

Davidson, John; Ryu, Sangjin

2014-11-01

Three common interfacial phenomena that occur daily are liquid drops in gas, gas bubbles in liquid and thin-film bubbles. One aspect that has been studied for these phenomena is the formation or pinch-off of the drop/bubble from the liquid/gas threads. In contrast to the formation of liquid drops in gas and gas bubbles in liquid, thin-film bubble pinch-off has not been well documented. Having thin-film interfaces may alter the pinch-off process due to the limiting factor of the film thickness. We observed the pinch-off of one common thin-film bubble, soap bubbles, in order to characterize its pinch-off behavior. We achieved this by constructing an experimental model replicating the process of a human producing soap bubbles. Using high-speed videography and image processing, we determined that the minimal neck radius scaled with the time left till pinch-off, and that the scaling law exponent was 2/3, similar to that of liquid drops in gas.

Passivity-Based Control for Two-Wheeled Robot Stabilization

Science.gov (United States)

Uddin, Nur; Aryo Nugroho, Teguh; Agung Pramudito, Wahyu

2018-04-01

A passivity-based control system design for two-wheeled robot (TWR) stabilization is presented. A TWR is a statically-unstable non-linear system. A control system is applied to actively stabilize the TWR. Passivity-based control method is applied to design the control system. The design results in a state feedback control law that makes the TWR closed loop system globally asymptotically stable (GAS). The GAS is proven mathematically. The TWR stabilization is demonstrated through computer simulation. The simulation results show that the designed control system is able to stabilize the TWR.

LNG systems for natural gas propelled ships

Science.gov (United States)

Chorowski, M.; Duda, P.; Polinski, J.; Skrzypacz, J.

2015-12-01

In order to reduce the atmospheric pollution generated by ships, the International Marine Organization has established Emission Controlled Areas. In these areas, nitrogen oxides, sulphur oxides and particulates emission is strongly controlled. From the beginning of 2015, the ECA covers waters 200 nautical miles from the coast of the US and Canada, the US Caribbean Sea area, the Baltic Sea, the North Sea and the English Channel. From the beginning of 2020, strong emission restrictions will also be in force outside the ECA. This requires newly constructed ships to be either equipped with exhaust gas cleaning devices or propelled with emission free fuels. In comparison to low sulphur Marine Diesel and Marine Gas Oil, LNG is a competitive fuel, both from a technical and economical point of view. LNG can be stored in vacuum insulated tanks fulfilling the difficult requirements of marine regulations. LNG must be vaporized and pressurized to the pressure which is compatible with the engine requirements (usually a few bar). The boil-off must be controlled to avoid the occasional gas release to the atmosphere. This paper presents an LNG system designed and commissioned for a Baltic Sea ferry. The specific technical features and exploitation parameters of the system will be presented. The impact of strict marine regulations on the system's thermo-mechanical construction and its performance will be discussed. The review of possible flow-schemes of LNG marine systems will be presented with respect to the system's cost, maintenance, and reliability.

Mathematical modeling of non-stationary gas flow in gas pipeline

Science.gov (United States)

Fetisov, V. G.; Nikolaev, A. K.; Lykov, Y. V.; Duchnevich, L. N.

2018-03-01

An analysis of the operation of the gas transportation system shows that for a considerable part of time pipelines operate in an unsettled regime of gas movement. Its pressure and flow rate vary along the length of pipeline and over time as a result of uneven consumption and selection, switching on and off compressor units, shutting off stop valves, emergence of emergency leaks. The operational management of such regimes is associated with difficulty of reconciling the operating modes of individual sections of gas pipeline with each other, as well as with compressor stations. Determining the grounds that cause change in the operating mode of the pipeline system and revealing patterns of these changes determine the choice of its parameters. Therefore, knowledge of the laws of changing the main technological parameters of gas pumping through pipelines in conditions of non-stationary motion is of great importance for practice.

Gas System 2013 at a glance

International Nuclear Information System (INIS)

2014-01-01

GRTgaz is a European leader in natural gas transmission, a world expert in gas transmission networks and systems, and an operator firmly committed to the energy transition. It owns and operates the gas transmission network throughout most of France and it manages the transmission network in Germany, thereby helping to ensure correct operation of the French and European gas market. It contributes to the energy security of regional supply systems and performs a public service mission to ensure the continuity of consumer supply. This document presents some key figures about GRTgaz activity in 2013: Total Consumption 2013 vs 2012: +1.4% gross consumption, -2% climate adjusted. Public Distribution Consumption 2013 vs 2012: +3.6% gross consumption, -1.9% climate adjusted. Industrial Customers Consumption 2013 vs 2012: -2.4% gross consumption. Power Generation: -50% since 2011. Industrial Customers 2012 vs 2013 (excluding power generation): +2%. Transported Quantities by GRTgaz 2013 vs 2012: Stability (-0.1%). LNG imports are down (-19%) compensated by pipe imports (+5%). Increasing outlet to the South-West, Congestion on North-South Link. Price spread between North and South. In 2013, gas gross consumption rose by 1.4 % on GRTgaz network, mainly because of colder climatic conditions, especially during the first half of the year, compared to 2012. Consumption of industrial customers connected to GRTgaz increased by 2 % (excluding power generation), mainly driven by sectors like Refineries, Chemistry, Glass and Materials. In 2013, GRTgaz transmission network ran under unusual gas flow conditions, especially with a continuing decrease of LNG imports (-19 %) and a low level in underground storages (-8 %)

Viscosity of the oil-in-water Pickering emulsion stabilized by surfactant-polymer and nanoparticle-surfactant-polymer system

Science.gov (United States)

Sharma, Tushar; Kumar, G. Suresh; Chon, Bo Hyun; Sangwai, Jitendra S.

2014-11-01

Information on the viscosity of Pickering emulsion is required for their successful application in upstream oil and gas industry to understand their stability at extreme environment. In this work, a novel formulation of oil-in-water (o/w) Pickering emulsion stabilized using nanoparticle-surfactant-polymer (polyacrylamide) system as formulated in our earlier work (Sharma et al., Journal of Industrial and Engineering Chemistry, 2014) is investigated for rheological stability at high pressure and high temperature (HPHT) conditions using a controlled-strain rheometer. The nanoparticle (SiO2 and clay) concentration is varied from 1.0 to 5.0 wt%. The results are compared with the rheological behavior of simple o/w emulsion stabilized by surfactant-polymer system. Both the emulsions exhibit non-Newtonian shear thinning behavior. A positive shift in this behavior is observed for surfactant-polymer stabilized emulsion at high pressure conditions. Yield stress is observed to increase with pressure for surfactant-polymer emulsion. In addition, increase in temperature has an adverse effect on the viscosity of emulsion stabilized by surfactant-polymer system. In case of nanoparticle-surfactant-polymer stabilized o/w emulsion system, the viscosity and yield stress are predominantly constant for varying pressure and temperature conditions. The viscosity data for both o/w emulsion systems are fitted by the Herschel-Bulkley model and found to be satisfactory. In general, the study indicates that the Pickering emulsion stabilized by nanoparticle-surfactant-polymer system shows improved and stable rheological properties as compared to conventional emulsion stabilized by surfactant-polymer system indicating their successful application for HPHT environment in upstream oil and gas industry.

Integral Field Spectroscopy of Markarian 273: Mapping High-Velocity Gas Flows and an Off-Nucleus Seyfert 2 Nebula.

Science.gov (United States)

Colina; Arribas; Borne

1999-12-10

Integral field optical spectroscopy with the INTEGRAL fiber-based system is used to map the extended ionized regions and gas flows in Mrk 273, one of the closest ultraluminous infrared galaxies. The Hbeta and [O iii] lambda5007 maps show the presence of two distinct regions separated by 4&arcsec; (3.1 kpc) along position angle (P.A.) 240 degrees. The northeastern region coincides with the optical nucleus of the galaxy and shows the spectral characteristics of LINERs. The southwestern region is dominated by [O iii] emission and is classified as a Seyfert 2. Therefore, in the optical, Mrk 273 is an ultraluminous infrared galaxy with a LINER nucleus and an extended off-nucleus Seyfert 2 nebula. The kinematics of the [O iii] ionized gas shows (1) the presence of highly disturbed gas in the regions around the LINER nucleus, (2) a high-velocity gas flow with a peak-to-peak amplitude of 2.4x103 km s-1, and (3) quiescent gas in the outer regions (at 3 kpc). We hypothesize that the high-velocity flow is the starburst-driven superwind generated in an optically obscured nuclear starburst and that the quiescent gas is directly ionized by a nuclear source, similar to the ionization cones typically seen in Seyfert galaxies.

Strategy of seismic disaster prevention plan of gas supply system in Great Tehran, Iran

Energy Technology Data Exchange (ETDEWEB)

Mohammadi, A.M.; Yousefi Pour, M.R. [Greater Tehran Gas Company, Tehran (Iran, Islamic Republic of); Yanou, Y.; Ogawa, Y.; Yamada, H. [Osaka Gas Co. Ltd., Osaka (Japan)

2004-07-01

Iran has suffered many devastating earthquakes. Tehran is surrounded by active faults including the North Tehran Fault and the South Ray Fault, making the city extremely vulnerable to large earthquakes. This paper proposes and outlines the basic anti-earthquake measures that would protect Greater Tehran Gas Company's (GTGC) gas supply systems from large earthquakes. Anti-earthquake measures focusing on reinforcing existing facilities and disaster prevention are detailed in this paper. The paper shows step-by-step procedures for the construction of a disaster-prevention system. The paper concludes that: GTGC's gas pipeline networks have high quake-resistance because they include welded steel pipes or polyethylene pipes; a gas remote shutoff system or gas automatic shut-off system should be installed as emergency measures in GTGC's earthquake disaster prevention measures; practical and actual training is also very important for all authorities, experts, engineers and staff involved in earthquake disaster prevention measures. 2 refs., 3 figs.

Stabilization of electrohydrodynamic jets by gas discharges and applications to printing

Science.gov (United States)

Korkut, Sibel

From integrated circuits to DNA hybridization micro arrays, many areas of research require flexible and reliable, high resolution surface patterning tools. A new surface patterning technique, electrohydrodynamic printing (EHDP) [1] provides high resolution and speed at the same time, which was not attainable with the existing direct surface patterning techniques. Stability of electrohydrodynamic (EHD) jets determines the accuracy of deployment in EHD printing [1-3]; therefore, understanding non-axisymmetric instability of the jet, which is caused by the surface charges, is crucial to successful operation. In this thesis, fast imaging and image analysis techniques are used to determine non-axisymmetric disturbance growth rates experimentally. Comparison of experimental instability growth rates with the theoretical estimations based on total current reveals a big discrepancy. It is also found that instability growth rates decrease and stability of EHD filaments is enhanced either by decreasing the electrode separation or by changing the surrounding gas. After considering all possible mechanisms, it is concluded that the main reason for stabilization is the increased ionization of the surrounding gas. Gas ionization results in partial neutralization of surface charges on the filament by the oppositely charged ions in the gas phase and stabilizes the jet. A new current balance including the charge transfer through the gas is developed to estimate the charge density left on the filament. Experimental and theoretical instability growth rates agree much better when the estimated charge density is used for the instability growth rate calculations. The second part of the thesis focuses on pattern formation on the surfaces. The final pattern produced with a colloidal suspension by EHDP depends on not only the stability of the jet but also the dynamics of the suspension and the stability of printed lines after the deployment. Rivulet instability, which causes deployed

Impurity screening of scrape-off plasma in a tokamak

International Nuclear Information System (INIS)

Kishimoto, Hiroshi; Tani, Keiji; Nakamura, Hiroo

1981-11-01

Impurity screening effect of a scrape-off layer has been studied in a tokamak, based on a simple model of wall-released impurity behavior. Wall-sputtered impurities are stopped effectively by the scrape-off plasma for a medium-Z or high-Z wall system while major part of impurities enters the main plasma in a low-Z wall system. The screening becomes inefficient with increase of scrape-off plasma temperature. Successive multiplication of recycling impurities in the scrape-off layer is large for a high-Z wall and is enhanced by a rise of scrape-off plasma temperature. The stability of plasma-wall interaction is determined by a multiplication factor of recycling impurities. (author)

Design and Stability of an On-Orbit Attitude Control System Using Reaction Control Thrusters

Science.gov (United States)

Hall, Robert A.; Hough, Steven; Orphee, Carolina; Clements, Keith

2016-01-01

Basic principles for the design and stability of a spacecraft on-orbit attitude control system employing on-off Reaction Control System (RCS) thrusters are presented. Both vehicle dynamics and the control system actuators are inherently nonlinear, hence traditional linear control system design approaches are not directly applicable. This paper has two main aspects: It summarizes key RCS design principles from earlier NASA vehicles, notably the Space Shuttle and Space Station programs, and introduces advances in the linear modelling and analyses of a phase plane control system derived in the initial development of the NASA's next upper stage vehicle, the Exploration Upper Stage (EUS). Topics include thruster hardware specifications, phase plane design and stability, jet selection approaches, filter design metrics, and RCS rotational maneuver logic.

Design and cost estimate for the SRL integrated hot off gas facility using selective adsorption

International Nuclear Information System (INIS)

Pence, D.T.; Kirstein, B.E.

1981-07-01

Based on the results of an engineering-scale demonstration program, a design and cost estimate were performed for a 25-m 3 /h (15-ft 3 /min) capacity pilot plant demonstration system using selective adsorption technology for installation at the Integrated Hot Off Gas Facility at the Savannah River Plant. The design includes provisions for the destruction of NO/sub x/ and the concentration and removal of radioisotopes of ruthenium, iodine-129, tritiated water vapor, carbon-14 contaminated carbon dioxide, and krypton-85. The nobel gases are separated by the use of selective adsorption on mordenite-type zeolites. The theory of noble gas adsorption on zeolites is essentially the same as that for the adsorption of noble gases on activated charcoals. Considerable detail is provided regarding the application of the theory to adsorbent bed designs and operation. The design is based on a comprehensive material balance and appropriate heat transfer calculations. Details are provided on techniques and procedures used for heating, cooling, and desorbing the adsorbent columns. Analyses are also given regarding component and arrangement selection and includes discussions on alternative arrangements. The estimated equipment costs for the described treatment system is about $1,400,000. The cost estimate includes a detailed equipment list of all the major component items in the design. Related technical issues and estimated system performance are also discussed

Design and cost estimate for the SRL integrated hot off gas facility using selective adsorption

Energy Technology Data Exchange (ETDEWEB)

Pence, D T; Kirstein, B E

1981-07-01

Based on the results of an engineering-scale demonstration program, a design and cost estimate were performed for a 25-m/sup 3//h (15-ft/sup 3//min) capacity pilot plant demonstration system using selective adsorption technology for installation at the Integrated Hot Off Gas Facility at the Savannah River Plant. The design includes provisions for the destruction of NO/sub x/ and the concentration and removal of radioisotopes of ruthenium, iodine-129, tritiated water vapor, carbon-14 contaminated carbon dioxide, and krypton-85. The nobel gases are separated by the use of selective adsorption on mordenite-type zeolites. The theory of noble gas adsorption on zeolites is essentially the same as that for the adsorption of noble gases on activated charcoals. Considerable detail is provided regarding the application of the theory to adsorbent bed designs and operation. The design is based on a comprehensive material balance and appropriate heat transfer calculations. Details are provided on techniques and procedures used for heating, cooling, and desorbing the adsorbent columns. Analyses are also given regarding component and arrangement selection and includes discussions on alternative arrangements. The estimated equipment costs for the described treatment system is about $1,400,000. The cost estimate includes a detailed equipment list of all the major component items in the design. Related technical issues and estimated system performance are also discussed.

Mobile Measurement of Methane and Ethane for the Detection and Attribution of Natural Gas Pipeline Leaks Using Off-Axis Integrated Output Spectroscopy

Science.gov (United States)

Leen, J. B.; Spillane, S.; Gardner, A.; Hansen, P. C.; Gupta, M.; Baer, D. S.

2015-12-01

Natural gas leaks pose a risk to public safety both because of potential explosions as well as from the greenhouse gas potential of fugitive methane. The rapid and cost effective detection of leaks in natural gas distribution is critical to providing a system that is safe for the public and the environment. Detection of methane from a mobile platform (vehicles, aircraft, etc.) is an accepted method of identifying leaks. A robust approach to differentiating pipeline gas (thermogenic) from other biogenic sources is the detection of ethane along with methane. Ethane is present in nearly all thermogenic gas but not in biogenic sources and its presence can be used to positively identify a gas sample. We present a mobile system for the simultaneous measurement of methane and ethane that is capable of detecting pipeline leaks and differentiating pipeline gas from other biogenic sources such as landfills, swamps, sewers, and enteric fermentation. The mobile system consists of a high precision GPS, sonic anemometer, and methane/ethane analyzer based on off-axis integrated cavity output spectroscopy (OA-ICOS). In order to minimize the system cost and facilitate the wide use of mobile leak detection, the analyzer operates in the near-infrared portion of the spectrum where lasers and optics are significantly less costly than in the mid-infrared. The analyzer is capable of detecting methane with a precision of detecting ethane with a precision of detection of leaks at speeds up to 50 mph. The sonic anemometer, GPS and analyzer inlet are mounted to a generic roof rack for attachment to available fleet vehicles. The system can detect leaks having a downwind concentration of as little as 10 ppb of methane above ambient, while leaks 500 ppb above ambient can be identified as thermogenic with greater than 99% certainty (for gas with 6% ethane). Finally, analysis of wind data provides an estimate of leak direction and distance. The system presented provides a robust, cost effective

Characterization of magnesium phosphate ceramics incorporating off-gas filters

International Nuclear Information System (INIS)

Yang, Jae Hwan; Lee, Chang Hwa; Heo, Chul Min; Jeon, Min Ku; Kang, Kweon Ho

2011-01-01

Radioactive cesium (Cs-137) and technetium (Tc-99) are discharged from the spent fuel as gaseous forms during the head-end process in pyroprocess. These off-gases are safely trapped via porous ceramic filters made of fly ash and calcium based material. Spent filters have to be treated, converted into proper waste forms in order to be disposed safely at a repository. Conventional technology used to make waste forms such as vitrification requires high temperature and complex process. In this study, we report a promising method to stabilize spent filters containing cesium and technetium using magnesium phosphate ceramics. Simulated spent filters were fabricated by vaporizing nonradioactive cesium and rhenium (a surrogate of Tc) through the voloxidizer. The crushed filters were mixed with raw materials of magnesium phosphate ceramics, to be stabilized in the phosphate ceramic matrix. Characterization of the waste forms was made by the compressive strength test, apparent porosity, XRD analysis, and SEM analysis. The sample containing filters showed the excellent mechanical property, with the highest compressive strength of 38.1 MPa in the sample with 30 wt% of Cs-filter. Microstructural analysis suggests that wastes are embedded in the crystalline phase formed by an acid-base reaction. (author)

Systematic selection of off-gas treatment at the Savannah River Site

International Nuclear Information System (INIS)

McKillip, S.T.; Rehder, T.E.

1992-01-01

At the Savannah River Site (SRS), from 1958--1985, effluent waste from the reactor fuel and target rod fabrication area (M-Area) was discharged to a settling basin. In 1981, monitoring wells detected groundwater contamination, specifically trichloroethylene and tetrachloroethylene, in the immediate vicinity of the basin. Under the auspices of Resource Conservation and Recovery Act (RCRA) the M-Area contamination must be addressed by a corrective action program until the volatile organic compound (VOC) concentrations reach Drinking Water Standards. This was initiated in 1985 with startup of a full-scale pump-and-treat air stripper system. Recently, remediation efforts have focused on vacuum extraction to treat vadose zone contamination not addressed by the original recovery wells, and additional pump-and-treat systems to achieve hydraulic control of the plume. Regulatory requirements allowed for discharge of VOCs to the atmosphere when the original remediation system was installed; however, 1990 amendments to the Clean Air Act will eventually require treatment of VOC contaminated air prior to discharge. This has ramifications to systems currently being design, as well as the existing systems. In response to the 1990 Clean Air Act amendments, SRS initiated a study to assess commercially available off-gas treatment technologies. These included carbon adsorption, thermal incineration, catalytic oxidation, absorption, condensation, and UV/peroxide destruction, and xenon flashlamp. Criteria used to evaluate the technologies were the thirty (30) year life cycle cost, permitting considerations, and manpower requirements. The study concluded that catalytic oxidation provided the most desirable combination of these elements

Gas hydrate dissociation off Svalbard induced by isostatic rebound rather than global warming.

Science.gov (United States)

Wallmann, Klaus; Riedel, M; Hong, W L; Patton, H; Hubbard, A; Pape, T; Hsu, C W; Schmidt, C; Johnson, J E; Torres, M E; Andreassen, K; Berndt, C; Bohrmann, G

2018-01-08

Methane seepage from the upper continental slopes of Western Svalbard has previously been attributed to gas hydrate dissociation induced by anthropogenic warming of ambient bottom waters. Here we show that sediment cores drilled off Prins Karls Foreland contain freshwater from dissociating hydrates. However, our modeling indicates that the observed pore water freshening began around 8 ka BP when the rate of isostatic uplift outpaced eustatic sea-level rise. The resultant local shallowing and lowering of hydrostatic pressure forced gas hydrate dissociation and dissolved chloride depletions consistent with our geochemical analysis. Hence, we propose that hydrate dissociation was triggered by postglacial isostatic rebound rather than anthropogenic warming. Furthermore, we show that methane fluxes from dissociating hydrates were considerably smaller than present methane seepage rates implying that gas hydrates were not a major source of methane to the oceans, but rather acted as a dynamic seal, regulating methane release from deep geological reservoirs.

Laboratory Evaporation Testing Of Hanford Waste Treatment Plant Low Activity Waste Off-Gas Condensate Simulant

Energy Technology Data Exchange (ETDEWEB)

Adamson, Duane J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Nash, Charles A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); McCabe, Daniel J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Crawford, Charles L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Wilmarth, William R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2014-01-01

The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream, LAW Off-Gas Condensate, from the off-gas system. The baseline plan for disposition of this stream is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility again. Alternate disposition of this stream would eliminate recycling of problematic components, and would enable de-coupled operation of the LAW melter and the Pretreatment Facilities. Eliminating this stream from recycling within WTP would also decrease the LAW vitrification mission duration and quantity of canistered glass waste forms. This LAW Off-Gas Condensate stream contains components that are volatile at melter temperatures and are problematic for the glass waste form. Because this stream recycles within WTP, these components accumulate in the Condensate stream, exacerbating their impact on the number of LAW glass containers that must be produced. Approximately 32% of the sodium in Supplemental LAW comes from glass formers used to make the extra glass to dilute the halides to be within acceptable concentration ranges in the LAW glass. Diverting the stream reduces the halides in the recycled Condensate and is a key outcome of this work. Additionally, under possible scenarios where the LAW vitrification facility commences operation prior to the WTP Pretreatment facility, identifying a disposition path becomes vitally important. This task examines the impact of potential future disposition of this stream in the Hanford tank farms, and investigates auxiliary evaporation to enable another disposition path. Unless an auxiliary evaporator is used, returning the stream to the tank farms would require evaporation in the 242-A evaporator. This stream is expected to be unusual because it will be very high in corrosive species that are volatile in the melter

Laboratory Evaporation Testing Of Hanford Waste Treatment Plant Low Activity Waste Off-Gas Condensate Simulant

International Nuclear Information System (INIS)

Adamson, Duane J.; Nash, Charles A.; McCabe, Daniel J.; Crawford, Charles L.; Wilmarth, William R.

2014-01-01

The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream, LAW Off-Gas Condensate, from the off-gas system. The baseline plan for disposition of this stream is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility again. Alternate disposition of this stream would eliminate recycling of problematic components, and would enable de-coupled operation of the LAW melter and the Pretreatment Facilities. Eliminating this stream from recycling within WTP would also decrease the LAW vitrification mission duration and quantity of canistered glass waste forms. This LAW Off-Gas Condensate stream contains components that are volatile at melter temperatures and are problematic for the glass waste form. Because this stream recycles within WTP, these components accumulate in the Condensate stream, exacerbating their impact on the number of LAW glass containers that must be produced. Approximately 32% of the sodium in Supplemental LAW comes from glass formers used to make the extra glass to dilute the halides to be within acceptable concentration ranges in the LAW glass. Diverting the stream reduces the halides in the recycled Condensate and is a key outcome of this work. Additionally, under possible scenarios where the LAW vitrification facility commences operation prior to the WTP Pretreatment facility, identifying a disposition path becomes vitally important. This task examines the impact of potential future disposition of this stream in the Hanford tank farms, and investigates auxiliary evaporation to enable another disposition path. Unless an auxiliary evaporator is used, returning the stream to the tank farms would require evaporation in the 242-A evaporator. This stream is expected to be unusual because it will be very high in corrosive species that are volatile in the melter

Stability aspects of plasmas penetrated by neutral gas with respect to velocity driven modes

International Nuclear Information System (INIS)

Ohlsson, D.

1978-08-01

A study of the stability properties of dense partially ionized plasmas immersed in strong magnetic fields with respect to velocity driven modes are presented. First we consider modes driven by mass motion perpendicular to the lines of force and the unperturbed density and temperature gradients. The presence of a third fluid, neutral gas, gives under certain conditions rise to unstable modes. This type of instability arises independently or whether the applied electric field transverse to the lines of force, driving the mass motion, being parallel or antiparallel to the unperturbed density and temperature gradient. The presence of neutral gas also corresponds to stabilizing effects which, in certain parameter regions, result in a quenching of this instability. It is shown that modes driven by velocity shear perpendicular to the lines of force are effectively stabilized by viscous and resistive effects. These effects are in certain parameter ranges strongly enhanced on account of plasma-neutral gas interaction effects. In collisionless plasmas, modes driven by velocity shear parallel to the lines of force are stabilized by compressibility effects parallel to the magnetic field and by finite Larmor radius effects. (author)

An off-line programming system for palletizing robot

Directory of Open Access Journals (Sweden)

Youdong Chen

2016-09-01

Full Text Available Off-line programming systems are essential tools for the effective use of palletizing robots. This article presents a dedicated off-line programming system for palletizing robots. According to the user practical requirements, there are many user-defined patterns that can’t be easily generated by commercial off-line robot programming systems. This study suggests a pattern generation method that users can easily define their patterns. The proposed method has been simulation and experiment. The results have attested the effectiveness of the proposed pattern generation method.

HOT CELL SYSTEM FOR DETERMINING FISSION GAS RETENTION IN METALLIC FUELS

Energy Technology Data Exchange (ETDEWEB)

Sell, D. A.; Baily, C. E.; Malewitz, T. J.; Medvedev, P. G.; Porter, D. L.; Hilton, B. A.

2016-09-01

A system has been developed to perform measurements on irradiated, sodium bonded-metallic fuel elements to determine the amount of fission gas retained in the fuel material after release of the gas to the element plenum. During irradiation of metallic fuel elements, most of the fission gas developed is released from the fuel and captured in the gas plenums of the fuel elements. A significant amount of fission gas, however, remains captured in closed porosities which develop in the fuel during irradiation. Additionally, some gas is trapped in open porosity but sealed off from the plenum by frozen bond sodium after the element has cooled in the hot cell. The Retained fission Gas (RFG) system has been designed, tested and implemented to capture and measure the quantity of retained fission gas in characterized cut pieces of sodium bonded metallic fuel. Fuel pieces are loaded into the apparatus along with a prescribed amount of iron powder, which is used to create a relatively low melting, eutectic composition as the iron diffuses into the fuel. The apparatus is sealed, evacuated, and then heated to temperatures in excess of the eutectic melting point. Retained fission gas release is monitored by pressure transducers during the heating phase, thus monitoring for release of fission gas as first the bond sodium melts and then the fuel. A separate hot cell system is used to sample the gas in the apparatus and also characterize the volume of the apparatus thus permitting the calculation of the total fission gas release from the fuel element samples along with analysis of the gas composition.

Electrical Grid Stability Enhancement using Smart Home Frequency-response Grid -Friendly Appliance System

Directory of Open Access Journals (Sweden)

Muawiya A. Kaigama

2016-03-01

Full Text Available Load shedding is a powerful scheme used for corrective and preventive measures; corrective to restore system’s stability and preventive to avoid catastrophic failure. However, the affected end users are deprived of power supply absolutely with no choice. This paper presents the design, development, feasibility and merits of Frequency-response Grid -Friendly Appliance System (FRGFAS in a smart home. FRGFAS is a decentralized Adaptive Load Shaving(ALS device that supports grid’s system stability by sensing grid’s frequency deterioration level and turns ON/OFF loads accordingly. The FRGFAS permits end users to carry out load shaving at their scale of preference in smart homes via flexible demand responses and automates outdoor lighting to optimum operational hours. FRGFAS obviate load shedding by shaving loads whenever the system is in distress and reset loads supply to the normal state when it stabilizes, this Consequently increases the end user comfort zone and averts a blackout.

An energy management system for off-grid power systems

Energy Technology Data Exchange (ETDEWEB)

Zelazo, Daniel [Universitaet Stuttgart, Institute for Systems Theory and Automatic Control, Stuttgart (Germany); Dai, Ran; Mesbahi, Mehran [University of Washington, Department of Aeronautics and Astronautics, Seattle, WA (United States)

2012-06-15

Next generation power management at all scales will rely on the efficient scheduling and operation of both generating units and loads to maximize efficiency and utility. The ability to schedule and modulate the demand levels of a subset of loads within a power system can lead to more efficient use of the generating units. These methods become increasingly important for systems that operate independently of the main utility, such as microgrid and off-grid systems. This work extends the principles of unit commitment and economic dispatch problems to off-grid power systems where the loads are also schedulable. We propose a general optimization framework for solving the energy management problem in these systems. An important contribution is the description of how a wide range of sources and loads, including those with discrete states, non-convex, and nonlinear cost or utility functions, can be reformulated as a convex optimization problem using, for example, a shortest path description. Once cast in this way, solution are obtainable using a sub-gradient algorithm that also lends itself to a distributed implementation. The methods are demonstrated by a simulation of an off-grid solar powered community. (orig.)

System evaluation of offshore platforms with gas liquefaction processes

DEFF Research Database (Denmark)

Nguyen, Tuong-Van; de Oliveira Júnior, Silvio

2018-01-01

Abstract Floating, production, storage and offloading plants are facilities used for offshore processing of hydrocarbons in remote locations. At present, the produced gas is injected back into the reservoir instead of being exported. The implementation of refrigeration processes offshore for liqu......Abstract Floating, production, storage and offloading plants are facilities used for offshore processing of hydrocarbons in remote locations. At present, the produced gas is injected back into the reservoir instead of being exported. The implementation of refrigeration processes offshore...... improvements are discussed based on an energy and exergy analysis. Compared to a standard platform where gas is directly injected into the reservoir, the total power consumption increases by up to 50%, and the exergy destruction within the processing plant doubles when a liquefaction system is installed....... It is therefore essential to conduct a careful analysis of the trade-off between the capital costs and operating revenues for such options....

Distortion definition and correction in off-axis systems

Science.gov (United States)

Da Deppo, Vania; Simioni, Emanuele; Naletto, Giampiero; Cremonese, Gabriele

2015-09-01

Off-axis optical configurations are becoming more and more used in a variety of applications, in particular they are the most preferred solution for cameras devoted to Solar System planets and small bodies (i.e. asteroids and comets) study. Off-axis designs, being devoid of central obstruction, are able to guarantee better PSF and MTF performance, and thus higher contrast imaging capabilities with respect to classical on-axis designs. In particular they are suitable for observing extended targets with intrinsic low contrast features, or scenes where a high dynamical signal range is present. Classical distortion theory is able to well describe the performance of the on-axis systems, but it has to be adapted for the off-axis case. A proper way to deal with off-axis distortion definition is thus needed together with dedicated techniques to accurately measure and hence remove the distortion effects present in the acquired images. In this paper, a review of the distortion definition for off-axis systems will be given. In particular the method adopted by the authors to deal with the distortion related issues (definition, measure, removal) in some off-axis instruments will be described in detail.

Computational stability of the Von Neumann--Richtmyer method for the case of the ideal gas law

International Nuclear Information System (INIS)

Hicks, D.L.

1978-07-01

Two stability concepts are of interest for partial difference equations--one arises in theory--the other in practice. The theoretical kind, referred to here as asymptotic stability, is essentially just asymptotic (as Δt, Δx → 0) boundedness of the discrete solution. The other kind, referred to here as computational stability, is stability for a fixed Δt and Δx--computational instability is indicated in practice by oscillatory behavior of the discrete approximation--in particular, oscillations of period 2Δx. This report is concerned with computational stability. Only approximate stability analyses of the von Neumann-Richtmyer scheme have been done for the case of the ideal gas law. Herein a more rigorous computational stability analysis is sought. The analysis leads to a recommendation for the improvement of the time step restriction in WONDY for the case of the ideal gas law

Removal efficiency of silver impregnated filter materials and performance of iodie filters in the off-gas of the Karlsruhe reprocessing plant WAK

International Nuclear Information System (INIS)

Herrmann, F.J.; Herrmann, B.; Hoeflich, V.

1997-01-01

An almost quantitative retention of iodine is required in reprocessing plants. For the iodine removal in the off-gas streams of a reprocessing plant various sorption materials had been tested under realistic conditions in the Karlsruhe reprocessing plant WAK in cooperation with the Karlsruhe research center FZK. The laboratory results achieved with different iodine sorption materials justified long time performance tests in the WAK Plant. Technical iodine filters and sorption materials for measurements of iodine had been tested from 1972 through 1992. This paper gives an overview over the most important results, Extended laboratory, pilot plant, hot cell and plant experiences have been performed concerning the behavior and the distribution of iodine-129 in chemical processing plants. In a conventional reprocessing plant for power reactor fuel, the bulk of iodine-129 and iodine-127 is evolved into the dissolver off-gas. The remainder is dispersed over many aqueous, organic and gaseous process and waste streams of the plant. Iodine filters with silver nitrate impregnated silica were installed in the dissolver off-gas of the Karlsruhe reprocessing plant WAK in 1975 and in two vessel vent systems in 1988. The aim of the Karlsruhe iodine research program was an almost quantitative evolution of the iodine during the dissolution process to remove as much iodine with the solid bed filters as possible. After shut down of the WAK plant in December 1990 the removal efficiency of the iodine filters at low iodine concentrations had been investigated during the following years. 12 refs., 2 figs., 2 tabs

Removal efficiency of silver impregnated filter materials and performance of iodie filters in the off-gas of the Karlsruhe reprocessing plant WAK

Energy Technology Data Exchange (ETDEWEB)

Herrmann, F.J.; Herrmann, B.; Hoeflich, V. [Wiederaufarbeitungsanlage Karlsruhe (Germany)] [and others

1997-08-01

An almost quantitative retention of iodine is required in reprocessing plants. For the iodine removal in the off-gas streams of a reprocessing plant various sorption materials had been tested under realistic conditions in the Karlsruhe reprocessing plant WAK in cooperation with the Karlsruhe research center FZK. The laboratory results achieved with different iodine sorption materials justified long time performance tests in the WAK Plant. Technical iodine filters and sorption materials for measurements of iodine had been tested from 1972 through 1992. This paper gives an overview over the most important results, Extended laboratory, pilot plant, hot cell and plant experiences have been performed concerning the behavior and the distribution of iodine-129 in chemical processing plants. In a conventional reprocessing plant for power reactor fuel, the bulk of iodine-129 and iodine-127 is evolved into the dissolver off-gas. The remainder is dispersed over many aqueous, organic and gaseous process and waste streams of the plant. Iodine filters with silver nitrate impregnated silica were installed in the dissolver off-gas of the Karlsruhe reprocessing plant WAK in 1975 and in two vessel vent systems in 1988. The aim of the Karlsruhe iodine research program was an almost quantitative evolution of the iodine during the dissolution process to remove as much iodine with the solid bed filters as possible. After shut down of the WAK plant in December 1990 the removal efficiency of the iodine filters at low iodine concentrations had been investigated during the following years. 12 refs., 2 figs., 2 tabs.

Robust Stability Analysis of the Space Launch System Control Design: A Singular Value Approach

Science.gov (United States)

Pei, Jing; Newsome, Jerry R.

2015-01-01

Classical stability analysis consists of breaking the feedback loops one at a time and determining separately how much gain or phase variations would destabilize the stable nominal feedback system. For typical launch vehicle control design, classical control techniques are generally employed. In addition to stability margins, frequency domain Monte Carlo methods are used to evaluate the robustness of the design. However, such techniques were developed for Single-Input-Single-Output (SISO) systems and do not take into consideration the off-diagonal terms in the transfer function matrix of Multi-Input-Multi-Output (MIMO) systems. Robust stability analysis techniques such as H(sub infinity) and mu are applicable to MIMO systems but have not been adopted as standard practices within the launch vehicle controls community. This paper took advantage of a simple singular-value-based MIMO stability margin evaluation method based on work done by Mukhopadhyay and Newsom and applied it to the SLS high-fidelity dynamics model. The method computes a simultaneous multi-loop gain and phase margin that could be related back to classical margins. The results presented in this paper suggest that for the SLS system, traditional SISO stability margins are similar to the MIMO margins. This additional level of verification provides confidence in the robustness of the control design.

Study of chemical stability of lemon oil components in sodium caseinate-lactose glycoconjugate-stabilized oil-in-water emulsions using solid-phase microextraction-gas chromatography.

Science.gov (United States)

Sabik, Hassan; Achouri, Allaoua; Alfaro, Maria; Pelletier, Marylène; Belanger, Denis; Britten, Michel; Fustier, Patrick

2014-07-25

A headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC/MS) method was developed to quantify lemon oil components and their degradation products in oil-in-water (O/W) emulsions prepared with sodium caseinate-heated-lactose (NaC-T + Lact) glycoconjugates as wall materials at two pH values (3.0 and 6.8). NaC-T + Lact conjugates had a significantly lower solubility at both pHs. Hydrolysis prior to glycation enhanced the solubility of glycoconjugates. Glycation with lactose did not improve the emulsion activity of NaC, while caseinate glycoconjugates showed much stronger antioxidant activity than the NaC-control sample. This might be due to the presence of melanoidins formed between the sugar and amino acid compounds as supported by the increase in browning intensity. Among the SPME-fibres tested, carboxen/polydimethylsiloxane (CAR/PDMS) provided better results in terms of sensitivity and selectivity for oil lemon components and their degradation products. Storage studies of these emulsions demonstrated that glycated NaC-T + Lact showed protection against peroxidation compared to the control. However, acidic pH conditions altered their stability over storage time. The major off-flavor components (α-terpineol and carvone) were inhibited in emulsions stabilized with glycated NaC, particularly at pH 6.8. The use of NaC-T + Lact conjugates showed improved encapsulation efficiency and stability and could be used as potential food ingredient-emulsifiers for stabilising citrus oils against oxidative degradation in food and beverage applications.

Classification and analysis of factors that affect stability of oil and gas enterprise staff

Directory of Open Access Journals (Sweden)

Zelinska Haluna Olexiivna

2016-12-01

Full Text Available The relevance of human resources as a strategic goal of sustainable development of oil and gas companies is determined. It is shown that the stability of staff, as the main component of the social components of sustainable enterprise development, research and evaluation needs in terms of an integrated system of factors influence the behavior of staff. Addressing issues related to the management personnel can be based classification study the factors affecting its stability in the formation of high quality human resources strategy. In particular noted that the needs of each employee should become an integral part of the concept of work and life balance. Analysis of the results of the study showed that in areas of oil and gas industry has a number of factors that negatively affect its operation and development, which are caused not only technical, technological and natural factors, but also due to neglect behavioral characteristics personnel. It is found that without understanding of the behavioral characteristics of staff and its values can`t implement a quality model of human resource management and provide optimal scenarios of oil companies in general.

Analysis of fire and smoke threat to off-gas HEPA filters in a transuranium processing plant

International Nuclear Information System (INIS)

Alvares, N.J.

1988-01-01

The author performed an analysis of fire risk to the high-efficiency particulate air (HEPA) filters that provide ventilation containment for a transuranium processing plant at the Oak Ridge National Laboratory. A fire-safety survey by an independent fire-protection consulting company had identified the HEPA filters in the facility's off-gas containment ventilation system as being at risk from fire effects. Independently studied were the ventilation networks and flow dynamics, and typical fuel loads were analyzed. It was found that virtually no condition for fire initiation exists and that, even if a fire started, its consequences would be minimal as a result of standard shut-down procedures. Moreover, the installed fire-protection system would limit any fire and thus would further reduce smoke or heat exposure to the ventilation components. 4 references, 4 figures, 5 tables

[Phylogeny of gas exchange systems].

Science.gov (United States)

Jürgens, K D; Gros, G

2002-04-01

Several systems of gas transport have developed during evolution, all of which are able to sufficiently supply oxygen to the tissues and eliminate the CO2 produced by the metabolism, in spite of great distances between the environment and the individual cells of the tissues. Almost all these systems utilize a combination of convection and diffusion steps. Convection achieves an efficient transport of gas over large distances, but requires energy and cannot occur across tissue barriers. Diffusion, on the other hand, achieves gas transport across barriers, but requires optimization of diffusion paths and diffusion areas. When two convectional gas flows are linked via a diffusional barrier (gas/fluid in the case of the avian lung, fluid/fluid in the case of gills), the directions in which the respective convectional movements pass each other are important determinants of gas exchange efficiency (concurrent, countercurrent and cross-current systems). The tracheal respiration found in insects has the advantage of circumventing the convective gas transport step in the blood, thereby avoiding the high energy expenditure of circulatory systems. This is made possible by a system of tracheae, ending in tracheoles, that reaches from the body surface to every cell within the body. The last step of gas transfer in these animals occurs by diffusion from the tracheoles ("air capillaries") to the mitochondria of cells. The disadvantage is that the tracheal system occupies a substantial fraction of body volume and that, due to limited mechanical stability of tracheal walls, this system would not be able to operate under conditions of high hydrostatic pressures, i. e. in large animals. Respiration in an "open" system, i. e. direct exposure of the diffusional barrier to the environmental air, eliminates the problem of bringing the oxygen to the barrier by convection, as is necessary in the avian and mammalian lung, in the insects' tracheal system and in the gills. An open system is

Automotive mechatronics automotive networking, driving stability systems, electronics

CERN Document Server

2015-01-01

As the complexity of automotive vehicles increases this book presents operational and practical issues of automotive mechatronics. It is a comprehensive introduction to controlled automotive systems and provides detailed information of sensors for travel, angle, engine speed, vehicle speed, acceleration, pressure, temperature, flow, gas concentration etc. The measurement principles of the different sensor groups are explained and examples to show the measurement principles applied in different types. Contents Basics of mechatronics.- Architecture.- Electronic control unit.- Software development.- Basic principles of networking.- Automotive networking.- Bus systems.- Automotive sensors.- Sensor measuring principles.- Sensor types.- Electric actuators.- Electrohydraulic actuators.- Electronic transmission control.- Electronic transmission control unit.- Modules for transmission control.- Antilock braking system.- Traction control system.- Electronic stability program.- Automatic brake functions.- Hydraulic modu...

A Computationally Efficient Equation of State for Ternary Gas Hydrate Systems

Science.gov (United States)

White, M. D.

2012-12-01

The potential energy resource of natural gas hydrates held in geologic accumulations, using lower volumetric estimates, is sufficient to meet the world demand for natural gas for nearly eight decades, at current rates of increase. As with other unconventional energy resources, the challenge is to economically produce the natural gas fuel. The gas hydrate challenge is principally technical. Meeting that challenge will require innovation, but more importantly, scientific research to understand the resource and its characteristics in porous media. The thermodynamic complexity of gas hydrate systems makes numerical simulation a particularly attractive research tool for understanding production strategies and experimental observations. Simply stated, producing natural gas from gas hydrate deposits requires releasing CH4 from solid gas hydrate. The conventional way to release CH4 is to dissociate the hydrate by changing the pressure and temperature conditions to those where the hydrate is unstable. Alternatively, the guest-molecule exchange technology releases CH4 by replacing it with more thermodynamically stable molecules (e.g., CO2, N2). This technology has three advantageous: 1) it sequesters greenhouse gas, 2) it potentially releases energy via an exothermic reaction, and 3) it retains the hydraulic and mechanical stability of the hydrate reservoir. Numerical simulation of the production of gas hydrates from geologic deposits requires accounting for coupled processes: multifluid flow, mobile and immobile phase appearances and disappearances, heat transfer, and multicomponent thermodynamics. The ternary gas hydrate system comprises five components (i.e., H2O, CH4, CO2, N2, and salt) and the potential for six phases (i.e., aqueous, nonaqueous liquid, gas, hydrate, ice, and precipitated salt). The equation of state for ternary hydrate systems has three requirements: 1) phase occurrence, 2) phase composition, and 3) phase properties. Numerical simulations that predict

Mixed Finite Element Simulation with Stability Analysis for Gas Transport in Low-Permeability Reservoirs

Directory of Open Access Journals (Sweden)

Mohamed F. El-Amin

2018-01-01

Full Text Available Natural gas exists in considerable quantities in tight reservoirs. Tight formations are rocks with very tiny or poorly connected pors that make flow through them very difficult, i.e., the permeability is very low. The mixed finite element method (MFEM, which is locally conservative, is suitable to simulate the flow in porous media. This paper is devoted to developing a mixed finite element (MFE technique to simulate the gas transport in low permeability reservoirs. The mathematical model, which describes gas transport in low permeability formations, contains slippage effect, as well as adsorption and diffusion mechanisms. The apparent permeability is employed to represent the slippage effect in low-permeability formations. The gas adsorption on the pore surface has been described by Langmuir isotherm model, while the Peng-Robinson equation of state is used in the thermodynamic calculations. Important compatibility conditions must hold to guarantee the stability of the mixed method by adding additional constraints to the numerical discretization. The stability conditions of the MFE scheme has been provided. A theorem and three lemmas on the stability analysis of the mixed finite element method (MFEM have been established and proven. A semi-implicit scheme is developed to solve the governing equations. Numerical experiments are carried out under various values of the physical parameters.

Study on Off-Design Steady State Performances of Helium Gas Turbo-compressor for HTGR-GT

International Nuclear Information System (INIS)

Qisen Ren; Xiaoyong Yang; Zhiyong Huang; Jie Wang

2006-01-01

The high temperature gas-cooled reactor (HTGR) coupled with direct gas turbine cycle is a promising concept in the future of nuclear power development. Both helium gas turbine and compressor are key components in the cycle. Under normal conditions, the mode of power adjustment is to control total helium mass in the primary loop using gas storage vessels. Meanwhile, thermal power of reactor core is regulated. This article analyzes off-design performances of helium gas turbine and compressors for high temperature gas-cooled reactor with gas turbine cycle (HTGR-GT) at steady state level of electric power adjustment. Moreover, performances of the cycle were simply discussed. Results show that the expansion ratio of turbine decreases as electric power reduces but the compression ratios of compressors increase, efficiencies of both turbine and compressors decrease to some extent. Thermal power does not vary consistently with electric power, the difference between these two powers increases as electric power reduces. As a result of much thermal energy dissipated in the temperature modulator set at core inlet, thermal efficiency of the cycle has a widely reduction under partial load conditions. (authors)

Numerical modeling of plasma plume evolution against ambient background gas in laser blow off experiments

International Nuclear Information System (INIS)

Patel, Bhavesh G.; Das, Amita; Kaw, Predhiman; Singh, Rajesh; Kumar, Ajai

2012-01-01

Two dimensional numerical modelling based on simplified hydrodynamic evolution for an expanding plasma plume (created by laser blow off) against an ambient background gas has been carried out. A comparison with experimental observations shows that these simulations capture most features of the plasma plume expansion. The plume location and other gross features are reproduced as per the experimental observation in quantitative detail. The plume shape evolution and its dependence on the ambient background gas are in good qualitative agreement with the experiment. This suggests that a simplified hydrodynamic expansion model is adequate for the description of plasma plume expansion.

Comparison of Direct and Indirect Gas Reactor Brayton Systems for Nuclear Electric Space Propulsion

International Nuclear Information System (INIS)

M Postlehwait; P DiLorenzo; S Belanger; J Ashcroft

2005-01-01

Gas reactor systems are being considered as candidates for use in generating power for the Prometheus-1 spacecraft, along with other NASA missions as part of the Prometheus program. Gas reactors offer a benign coolant, which increases core and structural materials options. However, the gas coolant has inferior thermal transport properties, relative to other coolant candidates such as liquid metals. This leads to concerns for providing effective heat transfer and for minimizing pressure drop within the reactor core. In direct gas Brayton systems, i.e. those with one or more Brayton turbines in the reactor cooling loop, the ability to provide effective core cooling and low pressure drop is further constrained by the need for a low pressure, high molecular weight gas, typically a mixture of helium and xenon. Use of separate primary and secondary gas loops, one for the reactor and one or more for the Brayton system(s) separated by heat exchanger(s), allows for independent optimization of the pressure and gas composition of each loop. The reactor loop can use higher pressure pure helium, which provides improved heat transfer and heat transport properties, while the Brayton loop can utilize lower pressure He-Xe. However, this approach requires a separate primary gas circulator and also requires gas to gas heat exchangers. This paper focuses on the trade-offs between the direct gas reactor Brayton system and the indirect gas Brayton system. It discusses heat exchanger arrangement and materials options and projects heat exchanger mass based on heat transfer area and structural design needs. Analysis indicates that these heat exchangers add considerable mass, but result in reactor cooling and system resiliency improvements

Time-dependent analysis of dissolver off-gas cleaning installations in a reprocessing plant

International Nuclear Information System (INIS)

Nagel, K.; Furrer, J.; Becker, G.; Obrowski, W.; Seghal, Y.P.; Weymann, J.

1983-01-01

The iodine- and aerosol-filtering test facility PASSAT of the Nuclear Research Centre in Karlsruhe has been investigated using a method which allows time-dependent analyses under accident conditions. This method which is closely related to fault-tree analysis needs subdivision in barriers of the system, and their logical combination in a tree. The barriers have binary states: defect and intact. The defect state will be described by a fault tree, whereas the intact state includes dependences of a barrier operation on physical parameters. The intact state enables time-dependent calculations. Calculations have been done for iodine filtering, because the best known entrance data are given. Results demonstrate clearly that the amount of iodine released increases only if both heaters failed, which heat the off-gas from 30 0 C to 80 0 C and then to 130 0 C. Additionally the integrated amount of iodine released depends on time period between the failures of the heaters

Gas hydrates stability zone thickness map of Indian deep offshore areas - A GIS based approach

Digital Repository Service at National Institute of Oceanography (India)

Rastogi, A.; Deka, B.; Bhattacharya, G.C.; Ramprasad, T.; KameshRaju, K.A.; Srinivas, K.; Murty, G.P.S.; Chaubey, A.K.; Ramana, M.V.; Subrahmanyam, V.; Sarma, K.V.L.N.S.; Desa, M.; Paropkari, A.L.; Menezes, A.A.A.; Murty, V.S.N.; Antony, M.K.; SubbaRaju, L.V.; Desa, E.; Veerayya, M.

hydrate occurrence in offshore regions and around the Indian sub-continent. This was accomplished by estimating the gas hydrate stability zone (GHSZ) thickness from the saptial analysis of the physical parameters that control the formation and stability...

Selective Reversible Absorption of the Industrial Off-Gas Components CO2 and NOx by Ionic Liquids

DEFF Research Database (Denmark)

Kaas-Larsen, Peter Kjartan; Thomassen, P.; Schill, Leonhard

2016-01-01

Ionic liquids are promising new materials for climate and pollution control by selective absorption of CO2 and NOx in industrial off-gases. In addition practical cleaning of industrial off gases seems to be attractive by use of ionic liquids distributed on the surface of porous, high surface area...... carriers in the form of so-called Supported Ionic Liquid Phase (SILP) materials. The potential of selected ionic liquids for absorption of CO2 and NOx are demonstrated and the possible interference of other gases influencing the stability and absorption capacity of the ionic liquids are investigated...

Measuring the influence of Canadian carbon stabilization programs on natural gas exports to the United States via a 'bottom-up' intertemporal spatial price equilibrium model

International Nuclear Information System (INIS)

Gabriel, S.A.; Vikas, S.; Ribar, D.M.

2000-01-01

In this paper, we present the results of a study of the impact of Canadian carbon stabilization programs on exports of natural gas to the United States. This work was based on a study conducted for the US Environmental Protection Agency. The Gas Systems Analysis model (GSAM), developed by ICF Consulting for the US Department of Energy, was used to gauge the overall impact of the stabilization programs on the North American natural gas market. GSAM is an intertemporal, spatial price equilibrium (SPE) type model of the North American natural gas system. Salient features of this model include characterization of over 17 000 gas production reservoirs with explicit reservoir-level geologic and economic information used to build up the supply side of the market. On the demand side, four sectors, residential, commercial, industrial and electric power generation, are characterized in the model. Lastly, both above and below ground storage facilities as well as a comprehensive pipeline network are used with the supply and demand side characterizations to arrive at estimates of market equilibrium prices and quantities and flows. 35 refs

Method and system for a gas tube switch-based voltage source high voltage direct current transmission system

Science.gov (United States)

She, Xu; Chokhawala, Rahul Shantilal; Zhou, Rui; Zhang, Di; Sommerer, Timothy John; Bray, James William

2016-12-13

A voltage source converter based high-voltage direct-current (HVDC) transmission system includes a voltage source converter (VSC)-based power converter channel. The VSC-based power converter channel includes an AC-DC converter and a DC-AC inverter electrically coupled to the AC-DC converter. The AC-DC converter and a DC-AC inverter include at least one gas tube switching device coupled in electrical anti-parallel with a respective gas tube diode. The VSC-based power converter channel includes a commutating circuit communicatively coupled to one or more of the at least one gas tube switching devices. The commutating circuit is configured to "switch on" a respective one of the one or more gas tube switching devices during a first portion of an operational cycle and "switch off" the respective one of the one or more gas tube switching devices during a second portion of the operational cycle.

Interval stability for complex systems

Science.gov (United States)

Klinshov, Vladimir V.; Kirillov, Sergey; Kurths, Jürgen; Nekorkin, Vladimir I.

2018-04-01

Stability of dynamical systems against strong perturbations is an important problem of nonlinear dynamics relevant to many applications in various areas. Here, we develop a novel concept of interval stability, referring to the behavior of the perturbed system during a finite time interval. Based on this concept, we suggest new measures of stability, namely interval basin stability (IBS) and interval stability threshold (IST). IBS characterizes the likelihood that the perturbed system returns to the stable regime (attractor) in a given time. IST provides the minimal magnitude of the perturbation capable to disrupt the stable regime for a given interval of time. The suggested measures provide important information about the system susceptibility to external perturbations which may be useful for practical applications. Moreover, from a theoretical viewpoint the interval stability measures are shown to bridge the gap between linear and asymptotic stability. We also suggest numerical algorithms for quantification of the interval stability characteristics and demonstrate their potential for several dynamical systems of various nature, such as power grids and neural networks.

Laser frequency stabilization using a transfer interferometer

Science.gov (United States)

Jackson, Shira; Sawaoka, Hiromitsu; Bhatt, Nishant; Potnis, Shreyas; Vutha, Amar C.

2018-03-01

We present a laser frequency stabilization system that uses a transfer interferometer to stabilize slave lasers to a reference laser. Our implementation uses off-the-shelf optical components along with microcontroller-based digital feedback, and offers a simple, flexible, and robust way to stabilize multiple laser frequencies to better than 1 MHz.

FFTF gas processing systems

International Nuclear Information System (INIS)

Halverson, T.G.

1977-01-01

The design and operation of the two radioactive gas processing systems at the Fast Flux Test Facility (FFTF) exemplifies the concept that will be used in the first generation of Liquid Metal Fast Breeder Reactors (LMFBR's). The two systems, the Radioactive Argon Processing System (RAPS) and the Cell Atmosphere Processing System (CAPS), process the argon and nitrogen used in the FFTF for cover gas on liquid metal systems and as inert atmospheres in steel lined cells housing sodium equipment. The RAPS specifically processes the argon cover gas from the reactor coolant system, providing for decontamination and eventual reuse. The CAPS processes radioactive gasses from inerted cells and other liquid metal cover gas systems, providing for decontamination and ultimate discharge to the atmosphere. The cryogenic processing of waste gas by both systems is described

Measurements of gas permeability and non-Darcy flow in gas-water-hydrate systems

Energy Technology Data Exchange (ETDEWEB)

Ersland, G.; Husebo, J.; Graue, A.; Kvamme, B. [Bergen Univ., Bergen (Norway). Dept. of Physics and Technology; Baldwin, B. [Green Country Petrophysics LLC, Dewey, OK (United States); Stevens, J.; Howard, J. [ConocoPhillips, OK (United States)

2008-07-01

Storage of carbon dioxide (CO{sub 2}) in natural gas hydrate reservoirs may offer stable long-term storage of a greenhouse gas while benefiting from methane production, without requiring heat. By exposing hydrate to a thermodynamically preferred hydrate former, CO{sub 2}, the hydrate may be maintained macroscopically in the solid state and retain the stability of the formation. However, there is concern over the flow capacity in such reservoirs. This depends on several factors, notably thermodynamic destabilization of hydrate in small pores due to capillary effects; the presence of liquid channels separating the hydrate from the mineral surfaces; and, the connectivity of gas or liquid filled pores and channels. This paper described a technique for measuring gas permeability in gas-water-hydrate systems. It reported on several experiments that measured gas permeability during stages of hydrate growth in sandstone core plugs. Interactions between minerals and surrounding molecules were also discussed. The formation of methane hydrate in porous media was monitored and quantified with magnetic resonance imaging (MRI). MRI images of hydrate growth within the porous rock were provided along with measurements of gas permeability and non-Darcy flow effects at various hydrate saturations. Gas permeability was measured at steady state flow of methane through the hydrate-bearing core sample. Significant gas permeability was recorded for porous sandstone even when hydrates occupied up to 60 per cent of the pore space. It was concluded that MRI imaging can be used effectively to map and quantify hydrate saturation in sandstone core plugs. 27 refs., 2 tabs., 10 figs.

New image-stabilizing system

Science.gov (United States)

Zhao, Yuejin

1996-06-01

In this paper, a new method for image stabilization with a three-axis image- stabilizing reflecting prism assembly is presented, and the principle of image stabilization in this prism assembly, formulae for image stabilization and working formulae with an approximation up to the third power are given in detail. In this image-stabilizing system, a single chip microcomputer is used to calculate value of compensating angles and thus to control the prism assembly. Two gyroscopes act as sensors from which information of angular perturbation is obtained, three stepping motors drive the prism assembly to compensate for the movement of image produced by angular perturbation. The image-stabilizing device so established is a multifold system which involves optics, mechanics, electronics and computer.

Stability investigations of relaxing molecular gas flows. Results and perspectives

Science.gov (United States)

Grigor'ev, Yurii N.; Ershov, Igor V.

2017-10-01

This article presents results of systematic investigations of a dissipative effect which manifests itself as the growth of hydrodynamic stability and suppression of turbulence in relaxing molecular gas flows. The effect can be a new way for control stability and laminar turbulent transition in aerodynamic flows. The consideration of suppression of inviscid acoustic waves in 2D shear flows is presented. Nonlinear evolution of large-scale vortices and Kelvin — Helmholtz waves in relaxing shear flows are studied. Critical Reynolds numbers in supersonic Couette flows are calculated analytically and numerically within the framework of both classical linear and nonlinear energy hydrodynamic stability theories. The calculations clearly show that the relaxation process can appreciably delay the laminar-turbulent transition. The aim of this article is to show the new dissipative effect, which can be used for flow control and laminarization.

Evaluation of RSG-GAS purification system and pool warm water layer supplier performance

International Nuclear Information System (INIS)

Sudiyono; Suhadi; Diah-Erlina-Lestari

2005-01-01

Function of RSG-GAS purification system and warm water supplier (KBE 02) are to pick up dissolve activation result and another dirts of warm water layer. To keep quality of water at the decided level. The system is equipped by heater to supply warm water layer on the reactor pool surface the distribution is to reduce radiation level in the operation hall area a speciality on the reactor pool surface. Line KBE 02 tomord beam tube headitty system supplies water necessary to be shielding to beam tube in use off time. Of the RSG-GAS purification system and pool warm water layer performance date can be shown north of water is always in good condition. To require the dechded requirement. Resin live time is two years and then months

Natural gas transmission and distribution model of the National Energy Modeling System

International Nuclear Information System (INIS)

1997-02-01

The Natural Gas Transmission and Distribution Model (NGTDM) is the component of the National Energy Modeling System (NEMS) that is used to represent the domestic natural gas transmission and distribution system. NEMS was developed in the Office of Integrated Analysis and Forecasting of the Energy Information Administration (EIA). NEMS is the third in a series of computer-based, midterm energy modeling systems used since 1974 by the EIA and its predecessor, the Federal Energy Administration, to analyze domestic energy-economy markets and develop projections. From 1982 through 1993, the Intermediate Future Forecasting System (IFFS) was used by the EIA for its analyses, and the Gas Analysis Modeling System (GAMS) was used within IFFS to represent natural gas markets. Prior to 1982, the Midterm Energy Forecasting System (MEFS), also referred to as the Project Independence Evaluation System (PIES), was employed. NEMS was developed to enhance and update EIA's modeling capability by internally incorporating models of energy markets that had previously been analyzed off-line. In addition, greater structural detail in NEMS permits the analysis of a broader range of energy issues. The time horizon of NEMS is the midterm period (i.e., through 2015). In order to represent the regional differences in energy markets, the component models of NEMS function at regional levels appropriate for the markets represented, with subsequent aggregation/disaggregation to the Census Division level for reporting purposes

Natural gas transmission and distribution model of the National Energy Modeling System

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-02-01

The Natural Gas Transmission and Distribution Model (NGTDM) is the component of the National Energy Modeling System (NEMS) that is used to represent the domestic natural gas transmission and distribution system. NEMS was developed in the Office of Integrated Analysis and Forecasting of the Energy Information Administration (EIA). NEMS is the third in a series of computer-based, midterm energy modeling systems used since 1974 by the EIA and its predecessor, the Federal Energy Administration, to analyze domestic energy-economy markets and develop projections. From 1982 through 1993, the Intermediate Future Forecasting System (IFFS) was used by the EIA for its analyses, and the Gas Analysis Modeling System (GAMS) was used within IFFS to represent natural gas markets. Prior to 1982, the Midterm Energy Forecasting System (MEFS), also referred to as the Project Independence Evaluation System (PIES), was employed. NEMS was developed to enhance and update EIA`s modeling capability by internally incorporating models of energy markets that had previously been analyzed off-line. In addition, greater structural detail in NEMS permits the analysis of a broader range of energy issues. The time horizon of NEMS is the midterm period (i.e., through 2015). In order to represent the regional differences in energy markets, the component models of NEMS function at regional levels appropriate for the markets represented, with subsequent aggregation/disaggregation to the Census Division level for reporting purposes.

Process Stability of Ultrasonic-Wave-Assisted Gas Metal Arc Welding

Science.gov (United States)

Fan, Chenglei; Xie, Weifeng; Yang, Chunli; Lin, Sanbao; Fan, Yangyang

2017-10-01

As a newly developed arc welding method, ultrasonic-wave-assisted arc welding successfully introduced power ultrasound into the arc and weld pool, during which the ultrasonic acts on the top of the arc in the coaxial alignment direction. The advanced process for molten metals can be realized by using an additional ultrasonic field. Compared with the conventional gas metal arc welding (GMAW), the welding arc is compressed, the droplet size is decreased, and the droplet transfer frequency is increased significantly in ultrasonic-wave-assisted GMAW (U-GMAW). However, the stability of the metal transfer has deep influence on the welding quality equally, and the ultrasonic wave effect on the stability of the metal transfer is a phenomenon that is not completely understood. In this article, the stabilities of the short-circuiting transfer process and globular transfer process are studied systematically, and the effect of ultrasonic wave on the metal transfer is analyzed further. The transfer frequency and process stability of the U-GMAW process are much higher than those of the conventional GMAW. Analytical results show that the additional ultrasonic wave is helpful for improving welding stability.

Non Lyapunov stability of a constant spatially developing 2-D gas flow

Science.gov (United States)

Balint, Agneta M.; Balint, Stefan; Tanasie, Loredana

2017-01-01

Different types of stabilities (global, local) and instabilities (global absolute, local convective) of the constant spatially developing 2-D gas flow are analyzed in a particular phase space of continuously differentiable functions, endowed with the usual algebraic operations and the topology generated by the uniform convergence on the plane. For this purpose the Euler equations linearized at the constant flow are used. The Lyapunov stability analysis was presented in [1] and this paper is a continuation of [1].

Stability properties of cold blanket systems for current driven modes

International Nuclear Information System (INIS)

Ohlsson, D.

1977-12-01

The stability problem of the boundary regions of cold blanket systems with induced currents parallel to the lines of force is formulated. Particular interest is focused on two types of modes: first electrostatic modes driven by the combined effects of a transverse resistivity gradient due to a spatially non-uniform electron temperature and a longitudinal current, second electromagnetic kink like modes driven by the torque arising from a transverse current density gradient and magnetic field perturbations. It is found that the combination of various dissipative and neutral gas effects introduces strong stabilizing effects within specific parameter ranges. For particular steady-state models investigated it is shown that these effects become of importance in laboratory plasmas at relatively high densities, low temperatures and moderate magnetic field strengths. Stability diagrams based on specific steady-state cold plasma blanket models will be presented

Method for removal and stabilization of mercury in mercury-containing gas streams

Science.gov (United States)

Broderick, Thomas E.

2005-09-13

The present invention is directed to a process and apparatus for removing and stabilizing mercury from mercury-containing gas streams. A gas stream containing vapor phase elemental and/or speciated mercury is contacted with reagent, such as an oxygen-containing oxidant, in a liquid environment to form a mercury-containing precipitate. The mercury-containing precipitate is kept or placed in solution and reacts with one or more additional reagents to form a solid, stable mercury-containing compound.

Gas purification project

International Nuclear Information System (INIS)

Broothaerts, J.; Claes, J.; Collard, G.; Goossens, W.; Harnie, R.; Heylen, P.; Vaesen, J.; Beukelaer, R. de; Dubois, G.; Glibert, R.; Mestrez, J.; Zahlen, A.

1975-06-01

Conceptual and experimental studies on LMFBR reprocessing and reactor off-gas purification systems are summarized. Iodine sorption on zeolites, low-temperature adsorption of noble gases on charcoal and catalytic oxidation of hydrogen, simulating tritium, are being studied in laboratory set-ups. A pilot loop with 25 m 3 h -1 throughput has been constructed. Results are quoted from the first phase of the iodine removal programme by scrubbing systems. Further extension of the test loop, comprising off-gases conditioning to removal of krypton in a cryodistillation unit, has been prepared. Delay-bed studies on 133 Xe extraction from LWR off-gases are reported. (author)

Development And Initial Testing Of Off-Gas Recycle Liquid From The WTP Low Activity Waste Vitrification Process - 14333

Energy Technology Data Exchange (ETDEWEB)

McCabe, Daniel J.; Wilmarth, William R.; Nash, Charles A.; Taylor-Pashow, Kathryn M.; Adamson, Duane J.; Crawford, Charles L.; Morse, Megan M.

2014-01-07

The Waste Treatment and Immobilization Plant (WTP) process flow was designed to pre-treat feed from the Hanford tank farms, separate it into a High Level Waste (HLW) and Low Activity Waste (LAW) fraction and vitrify each fraction in separate facilities. Vitrification of the waste generates an aqueous condensate stream from the off-gas processes. This stream originates from two off-gas treatment unit operations, the Submerged Bed Scrubber (SBS) and the Wet Electrospray Precipitator (WESP). Currently, the baseline plan for disposition of the stream from the LAW melter is to recycle it to the Pretreatment facility where it gets evaporated and processed into the LAW melter again. If the Pretreatment facility is not available, the baseline disposition pathway is not viable. Additionally, some components in the stream are volatile at melter temperatures, thereby accumulating to high concentrations in the scrubbed stream. It would be highly beneficial to divert this stream to an alternate disposition path to alleviate the close-coupled operation of the LAW vitrification and Pretreatment facilities, and to improve long-term throughput and efficiency of the WTP system. In order to determine an alternate disposition path for the LAW SBS/WESP Recycle stream, a range of options are being studied. A simulant of the LAW Off-Gas Condensate was developed, based on the projected composition of this stream, and comparison with pilot-scale testing. The primary radionuclide that vaporizes and accumulates in the stream is Tc-99, but small amounts of several other radionuclides are also projected to be present in this stream. The processes being investigated for managing this stream includes evaporation and radionuclide removal via precipitation and adsorption. During evaporation, it is of interest to investigate the formation of insoluble solids to avoid scaling and plugging of equipment. Key parameters for radionuclide removal include identifying effective precipitation or ion

Evidence for faulting related to dissociation of gas hydrate and release of methane off the southeastern United States

Science.gov (United States)

Dillon, William P.; Danforth, W.W.; Hutchinson, D.R.; Drury, R.M.; Taylor, M.H.; Booth, J.S.

1998-01-01

This paper is part of the special publication Gas hydrates: relevance to world margin stability and climatic change (eds J.P. Henriet and J. Mienert). An irregular, faulted, collapse depression about 38 x 18 km in extent is located on the crest of the Blake Ridge offshore from the south- eastern United States. Faults disrupt the sea floor and terminate or sole out about 40-500 m below the sea floor at the base of the gas hydrate stable zone, which is identified from the location of the bottom simulating reflection (BSR). Normal faults are common but reverse faults and folds also are widespread. Folds commonly convert upward into faults. Sediment diapirs and deposits of sediments that were erupted onto the sea floor are also present. Sea-floor depressions at faults may represent locations of liquid/gas vents. The collapse was probably caused by overpressures and by the decoupling of the overlying sediments by gassy muds that existed just beneath the zone of gas hydrate stability.

Separation of the fission product noble gases krypton and xenon from dissolver off-gas in reprocessing HTGR-fuel

Energy Technology Data Exchange (ETDEWEB)

Bohnenstingl, J.; Djoa, S. H.; Laser, M.; Mastera, S.; Merz, E.; Morschl, P.

1976-04-15

This paper describes a process developed for the retainment and separation of volatile (³H, ^{129 +131}I) and gaseous (⁸⁵Kr, Xe) fission products from the off-gas produced during dissolution of HTGR-fuel. To prevent unnecessary dilution of liberated noble gases by surrounding atmosphere, a helium purge-gas cycle is applied to enable a coarse fractionating of krypton and xenon by cold-trapping at about 80 deg K after precleaning the gas stream. The process consists of the following steps: deposition of droplets and solid aerosols; chemisorption of iodine on silver impregnated silica gel; catalytic removal of nitrogen oxides and oxygen; drying of the process gas stream; final filtering of abraded solids; deposition of xenon in solid form at 80 deg K and low subpressure; deposition of krypton in solid form at 80 deg K after compression to about 6 bar; decontamination of ⁸⁵krypton-containing xenon by batch distillation for eventual industrial utilization; and removal of nitrogen and argon enrichment during continuous operation in the purge-gas stream by inleaking air with charcoal. A continuously operating dissolver vessel, closed to the surrounding atmosphere, yields a very high content of noble gases, e.g., 0.35 vol % krypton and 2.0 vol % xenon. The presented off-gas treatment unit is operated in cold runs with 1/3 of the full capacity and can treat about 1 m³ STP/h helium, corresponding to a quantity of about 10,000 MW(e) HTGR-fuel reprocessing plant.

Separation of the fission product noble gases krypton and xenon from dissolver off-gas in reprocessing HTGR-fuel

International Nuclear Information System (INIS)

Bohnenstingl, J.; Djoa, S.H.; Laser, M.; Mastera, S.; Merz, E.; Morschl, P.

1976-01-01

This paper describes a process developed for the retainment and separation of volatile ( 3 H, 129+131 I) and gaseous ( 85 Kr, Xe) fission products from the off-gas produced during dissolution of HTGR-fuel. To prevent unnecessary dilution of liberated noble gases by surrounding atmosphere, a helium purge-gas cycle is applied to enable a coarse fractionating of krypton and xenon by cold-trapping at about 80 0 K after precleaning the gas stream. The process consists of the following steps: deposition of droplets and solid aerosols; chemisorption of iodine on silver impregnated silica gel; catalytic removal of nitrogen oxides and oxygen; drying of the process gas stream; final filtering of abraded solids; deposition of xenon in solid form at 80 0 K and low subpressure; deposition of krypton in solid form at 80 0 K after compression to about 6 bar; decontamination of 85 Kr-containing xenon by batch distillation for eventual industrial utilization; and removal of nitrogen and argon enrichment during continuous operation in the purge-gas stream by inleaking air with charcoal. A continuously operating dissolver vessel, closed to the surrounding atmosphere, yields a very high content of noble gases, i.e., 0.35 vol % krypton and 2.0 vol % xenon. The presented off-gas treatment unit is operated in cold runs with 1 / 3 of the full capacity and can treat about 1 m 3 STP/h helium, corresponding to a quantity of about 10,000 MW/sub e/ HTGR-fuel reprocessing plant

Patterning of oxide-hardened gold black by photolithography and metal lift-off

Science.gov (United States)

Panjwani, Deep; Yesiltas, Mehmet; Nath, Janardan; Maukonen, D. E.; Rezadad, Imen; Smith, Evan M.; Peale, R. E.; Hirschmugl, Carol; Sedlmair, Julia; Wehlitz, Ralf; Unger, Miriam; Boreman, Glenn

2014-01-01

A method to pattern infrared-absorbing gold black by conventional photolithography and lift-off is described. A photo-resist pattern is developed on a substrate by standard photolithography. Gold black is deposited over the whole by thermal evaporation in an inert gas at ˜1 Torr. SiO2 is then deposited as a protection layer by electron beam evaporation. Lift-off proceeds by dissolving the photoresist in acetone. The resulting sub-millimeter size gold black patterns that remain on the substrate retain high infrared absorption out to ˜5 μm wavelength and exhibit good mechanical stability. This technique allows selective application of gold black coatings to the pixels of thermal infrared imaging array detectors.

Tipping points for carbon dioxide and air pollution benefits: an energy systems analysis of natural gas verses electric technologies in the U.S. buildings sector

Science.gov (United States)

Our analysis examines emission trade-offs between electricity and natural gas use in the buildings sector at the system level, including upstream emissions from the electric sector and natural gas mining emissions.

On-site and off-site atmospheric PBDEs in an electronic dismantling workshop in south China: Gas-particle partitioning and human exposure assessment

International Nuclear Information System (INIS)

An Taicheng; Zhang Delin; Li Guiying; Mai Bixian; Fu Jiamo

2011-01-01

Gas samples and total suspended particle during work and off work time were investigated on-site and off-site electronic waste dismantling workshop (I- and O-EWDW), then compared with plastic recycling workshop (PRW) and waste incineration plant (WIP). TSP concentrations and total PBDE were 0.36-2.21 mg/m 3 and 27-2975 ng/m 3 at different workshops, respectively. BDE-47, -99, and -209 were major ΣPBDE congeners at I-EWDW and WIP, while BDE-209 was only dominant congener in PRW and control sites during work time and all sites during off work time. The gas-particle partitioning result was well correlated with the subcooled liquid vapor pressure for all samples, except for WIP and I-EDWD, at park during work time, and residential area during off work time. The predicted urban curve fitted well with measured φ values at O-DEWD during work time, whereas it was slightly overestimated or underestimated for others. Exposure assessment revealed the highest exposure site was I-EDWD. - Highlights: → On- and off-site atmospheric PBDEs was monitored in e-waste dismantling workshops in south China. → The gas-particle partitioning result was well correlated with the subcooled liquid vapor pressure for some samples. → Exposure assessment revealed that workers in I-EDWD were the highest exposure population. - The findings of this study may serve as a valuable reference for future risk assessment and environmental management in Guiyu, South China.

The Stability of CI02 as a Product of Gas Phase Decontamination Treatments

International Nuclear Information System (INIS)

Simmons, D. W.

1994-01-01

The gas phase decontamination project is investigating the use of chlorine trifluoride (ClF 3 ) to fluorinate nonvolatile uranium deposits to produce uranium hexafluoride (UF 6 ) gas. The potential existence of chlorine dioxide (ClO 2 ) during gas phase decontamination with ClF 3 has been the subject of recent safety discussions. Some of the laboratory data collected during feasibility studies of the gas phase process has been evaluated for the presence of ClO 2 in the product gas stream. The preliminary evidence to date can be summarized as follows: (1) ClO 2 was not detected in the flow loop in the absence of ClF 3 ; (2) ClO 2 was not detected in the static reactors in the absence of both ClF 3 and ClF; and (3) ClO 2 was detected in a static reactor in the absence of all fluorinating gases. The experimental evidence suggests that ClO 2 will not exist in the presence of ClF 3 , ClF, or UF 6 . The data analyzed to date is insufficient to determine the stability of ClO 2 in the presence of ClO 2 F. Thermodynamic calculations of the ClF 3 + H 2 O system support the experimental evidence, and suggest that ClO 2 will not exist in the presence of ClO 2 F. Additional experimental efforts are needed to provide a better understanding of the gas phase ClF 3 treatments and the product gases. However, preliminary evidence to date suggests that ClO 2 should not be present as a product during the normal operations of the gas phase decontamination project

Early Leakage Protection System of LPG (Liquefied Petroleum Gas) Based on ATMega 16 Microcontroller

Science.gov (United States)

Sriwati; Ikhsan Ilahi, Nur; Musrawati; Baco, Syarifuddin; Suyuti'Andani Achmad, Ansar; Umrianah, Ejah

2018-04-01

LPG (Liquefied Petroleum Gas). LPG is a hydrocarbon gas production from refineries and gas refinery with the major components of propane gas (C3H8) and butane (C4H10). Limit flame (Flammable Range) or also called gas with air. Value Lower Explosive Limit (LEL) is the minimum limit of the concentration of fuel vapor in the air which if there is no source of fire, the gas will be burned. While the value of the Upper Explosive Limit (UEL), which limits the maximum concentration of fuel vapor in the air, which if no source of fire, the gas will be burned. Protection system is a defend mechanism of human, equipment, and buildings around the protected area. Goals to be achieved in this research are to design a protection system against the consequences caused by the leakage of LPG gas based on ATmega16 microcontroller. The method used in this research is to reduce the levels of leaked LPG and turned off the power source when the leakage of LPG is on the verge of explosive limit. The design of this protection system works accurately between 200 ppm up to 10000 ppm, which is still below the threshold of explosive. Thus protecting the early result of that will result in the leakage of LPG gas.

Evaluation of the performance of thermal diffusion column separating binary gas mixtures with continuous draw-off

International Nuclear Information System (INIS)

Kitamoto, Asashi; Shimizu, Masami; Takashima, Yoichi

1977-01-01

Advanced transport relations involving three column constants, H sup(σ), K sub(c)sup(σ) and K sub(d)sup(σ), are developed to describe the separation performance of a thermal diffusion column with continuous draw-off. These constants were related to some integral functions of velocity profile, temperature distribution, density of gas mixture and characteristic values of transport coefficients. The separation of binary gas mixture by this technique was so effective that three reasonable factors had to be introduced into the column constants in the theory. They are a circulation constant of natural convection, a definition of characteristic mean temperature and a definition of mean composition over the column. The separation performance and the column constants also varied with the distortion of velocity profile due to continuous draw-off from the top or the bottom of column. However, its effect was not large, compared with the other factors mentioned above. The theory presented here makes possible to estimate the separation performance of hot-wire type thermal diffusion column with high accuracy. (auth.)

Analysis of copper losses throughout weak acid effluent flows generated during off-gas treatment in the New Copper Smelter RTB Bor

Directory of Open Access Journals (Sweden)

Dragana Ivšić-Bajčeta

2013-09-01

Full Text Available The previous inadequate treatment of off-gas in RTB Bor in Serbia has resulted in serious pollution of the environment and the possibly high losses of copper through the effluent flows. The project of New Copper Smelter RTB Bor, besides the new flash smelting furnace (FSF and the reconstruction of Pierce-Smith converter (PSC, includes more effective effluent treatment. Paper presents an analysis of the new FSF and PSC off-gas treatment, determination of copper losses throughout generated wastewaters and discussion of its possible valorization. Assumptions about the solubility of metals phases present in the FSF and PSC off-gas, obtained by the treatment process simulation, were compared with the leaching results of flue dusts. Determined wastewaters characteristics indicate that the PSC flow is significantly richer in copper, mostly present in insoluble metallic/sulfide form, while the FSF flow has low concentration of copper in the form of completely soluble oxide/sulfate. The possible scenario for the copper valorization, considering arsenic and lead as limiting factors, is the separation of the FSF and PSC flows, return of the metallic/sulfide solid phase to the smelting process and recovery from the sulfate/oxide liquid phase.

Organic compound destruction and removal efficiency (DRE) for plasma incinerator off-gases using an electrically heated secondary combustion chamber

International Nuclear Information System (INIS)

Whitworth, C.G.; Babko-Malyi, S.; Battleson, D.M.; Olstad, S.J.

1998-01-01

The US Department of Energy (DOE) sponsored a series pilot-scale plasma incineration tests of simulated mixed wastes at the MSE Technology Applications, Inc. technology development test facility in Butte, MT. One of the objectives of the test series was to assess the ability of an electrically heated afterburner to destroy organic compounds that may be present in the off-gases resulting from plasma incineration of mixed wastes. The anticipated benefit of an electrically heated afterburner was to decrease total off-gas volume by 50% or more, relative to fossil fuel-fired afterburners. For the present test series, feeds of interest to the DOE Mixed Waste Focus Area (MWFA) were processed in a plasma centrifugal furnace while metering selected organic compounds upstream of the electrically heated afterburner. The plasma furnace was equipped with a transferred-mode torch and was operated under oxidizing conditions. Feeds consisted of various mixtures of soil, plastics, portland cement, silicate fines, diesel fuel, and scrap metals. Benzene, chloroform, and 1,1,1-trichloroethane were selected for injection as simulates of organics likely to be present in DOE mixed wastes, and because of their relative rankings on the US Environmental Protection Agency (EPA) thermal stability index. The organic compounds were injected into the off-gas system at a nominal concentration of 2,000 ppmv. The afterburner outlet gas stream was periodically sampled, and analyzed by gas chromatography/mass spectrometry. For the electrically heated afterburner, at operating temperatures of 1,800--1,980 F (982--1,082 C), organic compound destruction and removal efficiencies (DREs) for benzene, chloroform, and 1,1,1-trichloroethane were found to be > 99.99%

Power system stabilizer control for wind power to enhance power system stability

OpenAIRE

Domínguez García, José Luís; Gomis Bellmunt, Oriol; Bianchi, Fernando Daniel; Sumper, Andreas

2011-01-01

The paper presents a small signal stability analysis for power systems with wind farm interaction. Power systems have damping oscillation modes that can be excited by disturbance or fault in the grid. The power converters of the wind farms can be used to reduce these oscillations and make the system more stable. These ideas are explored to design a power system stabilized (PSS) for a network with conventional generators and a wind farm in order to increase the damping of the oscillation...

Trade-off between quantum capacitance and thermodynamic stability of defected graphene: an implication for supercapacitor electrodes

Science.gov (United States)

Srivastava, Anurag; SanthiBhushan, Boddepalli

2018-03-01

Defects are inevitable most of the times either at the synthesis, handling or processing stage of graphene, causes significant deviation of properties. The present work discusses the influence of vacancy defects on the quantum capacitance as well as thermodynamic stability of graphene, and the nitrogen doping pattern needs to be followed to attain a trade-off between these two. Density Functional Theory (DFT) calculations have been performed to analyze various vacancy defects and different possible nitrogen doping patterns at the vacancy site of graphene, with an implication for supercapacitor electrodes. The results signify that vacancy defect improves the quantum capacitance of graphene at the cost of thermodynamic stability, while the nitrogen functionalization at the vacancy improves thermodynamic stability and quantum capacitance both. It has been observed that functionalizing all the dangling carbons at the defect site with nitrogen is the key to attain high thermodynamic stability as well as quantum capacitance. Furthermore, the results signify the suitability of these functionalized graphenes for anode electrode of high energy density asymmetric supercapacitors.

Performance of a high repetition pulse rate laser system for in-gas-jet laser ionization studies with the Leuven laser ion source LISOL

International Nuclear Information System (INIS)

Ferrer, R.; Sonnenschein, V.T.; Bastin, B.; Franchoo, S.; Huyse, M.; Kudryavtsev, Yu.; Kron, T.; Lecesne, N.; Moore, I.D.; Osmond, B.; Pauwels, D.; Radulov, D.; Raeder, S.; Rens, L.

2012-01-01

The laser ionization efficiency of the Leuven gas cell-based laser ion source was investigated under on- and off-line conditions using two distinctly different laser setups: a low-repetition rate dye laser system and a high-repetition rate Ti:sapphire laser system. A systematic study of the ion signal dependence on repetition rate and laser pulse energy was performed in off-line tests using stable cobalt and copper isotopes. These studies also included in-gas-jet laser spectroscopy measurements on the hyperfine structure of 63 Cu. A final run under on-line conditions in which the radioactive isotope 59 Cu (T 1/2 = 81.5 s) was produced, showed a comparable yield of the two laser systems for in-gas-cell ionization. However, a significantly improved time overlap by using the high-repetition rate laser system for in-gas-jet ionization was demonstrated by an increase of the overall duty cycle, and at the same time, pointed to the need for a better shaped atomic jet to reach higher ionization efficiencies.

Convergent systems vs. incremental stability

NARCIS (Netherlands)

Rüffer, B.S.; Wouw, van de N.; Mueller, M.

2013-01-01

Two similar stability notions are considered; one is the long established notion of convergent systems, the other is the younger notion of incremental stability. Both notions require that any two solutions of a system converge to each other. Yet these stability concepts are different, in the sense

Experimental analysis of diffusion absorption refrigerator driven by electrical heater and engine exhaust gas

Directory of Open Access Journals (Sweden)

Mohamed Izzedine Serge ADJIBADE

2017-09-01

Full Text Available This work presents an experimental study of H20-NH3-H2 diffusion absorption refrigeration under two types of energy sources, i.e. the conventional electric energy from grid (electric and exhaust gas from internal combustion engine. Dynamic method is used to evaluate the behavior of the components of the system for both energy sources. Results obtained show that the performance of each component under different types of energy sources is almost coherent. For the generator, the electrical heater system requires more time to warm up, around three minutes, compared to the 40 s for system running with exhaust gas. For the evaporator, the decreasing rate is higher for the exhaust gas source and it took only about two hours to reach steady-state while for the electrical heat, the steady-state is reached after about seven hours of operation. For both energy sources, the evaporation temperature stabilizes to 3 °C and the minimum temperature to boil off ammonia is around 140 °C.

Thinning of Inner Retinal Layers after Vitrectomy with Silicone Oil versus Gas Endotamponade in Eyes with Macula-Off Retinal Detachment.

Science.gov (United States)

Purtskhvanidze, Konstantine; Hillenkamp, Jost; Tode, Jan; Junge, Olaf; Hedderich, Jürgen; Roider, Johann; Treumer, Felix

2017-01-01

To evaluate retinal layer thickness with optical coherence tomography (OCT) in eyes with macula-off retinal detachment after silicone oil (SiO) or gas endotamponade. Cross-sectional study of 40 eyes with macula-off rhegmatogenous retinal detachment that underwent vitrectomy. 20 eyes received SiO tamponade and 20 matched eyes received gas. 33 healthy fellow eyes served as controls. Macular spectral domain OCT was performed with automated layer detection in the 5 inner subfields of the Early Treatment Diabetic Retinopathy Study (ETDRS) map. Comparing the SiO group with the gas group, the ganglion cell layer showed a significant thinning in all fields of the inner ring of the ETDRS map, the inner plexiform layer in the nasal, superior and temporal quadrants, and the outer plexiform layer in the nasal quadrant. Inner retinal layers in the fovea/parafovea were significantly thinner in the SiO group. Prospective studies are warranted to further elucidate possible retinal adverse effects of SiO tamponade. © 2017 S. Karger AG, Basel.

Gas tagging system development in Japan

International Nuclear Information System (INIS)

Sekiguchi, N.; Rindo, H.; Akiyama, T.; Miyazawa, T.; Heki, H.

1981-05-01

The Gas tagging method has been considered to be most desirable for a failed fuel location system for the fast breeder reactor, regarding the component reduction in the reactor vessel and rapid location during reactor operation. The gas tagging system has been designed by referring to R and D results obtained in Japan and other countries. The designed system is comprised of tag gas filling pins, cover gas sampling system, tag gas recovery and enrichment system, tag gas analyzer and system control and data handling computers. The main specifications for this system have been decided as follows; 1) Main function is location of failed fuels in core and a part of blanket region, 2) Identification capability is each subassembly, 3) Time for identification is within a few days, 4) Continuous operation with automatic start at fuel failure, 5) Detection sensitivity must cover both gas leak and pin burst. In designing the gas tagging system, the following R and D items were selected; 1) System design study, 2) Tag gas capsule development, 3) Modeling the tag gas behavior in reactor primary cooling system, 4) Tag gas recovery and enrichment system, 5) Computer code development for tag gas isotope ratio change estimation. Details of the Japanese gas tagging system development appear in this paper. (author)

Simultaneous overpass off nadir (SOON): a method for unified calibration/validation across IEOS and GEOSS system of systems

Science.gov (United States)

Ardanuy, Philip; Bergen, Bill; Huang, Allen; Kratz, Gene; Puschell, Jeff; Schueler, Carl; Walker, Joe

2006-08-01

The US operates a diverse, evolving constellation of research and operational environmental satellites, principally in polar and geosynchronous orbits. Our current and enhanced future domestic remote sensing capability is complemented by the significant capabilities of our current and potential future international partners. In this analysis, we define "success" through the data customers' "eyes": participating in the sufficient and continuously improving satisfaction of their mission responsibilities. To successfully fuse together observations from multiple simultaneous platforms and sensors into a common, self-consistent, operational environment requires that there exist a unified calibration and validation approach. Here, we consider develop a concept for an integrating framework for absolute accuracy; long-term stability; self-consistency among sensors, platforms, techniques, and observing systems; and validation and characterization of performance. Across all systems, this is a non-trivial problem. Simultaneous Nadir Overpasses, or SNO's, provide a proven intercomparison technique: simultaneous, collocated, co-angular measurements. Many systems have off-nadir elements, or effects, that must be calibrated. For these systems, the nadir technique constrains the process. We define the term "SOON," for simultaneous overpass off nadir. We present a target architecture and sensitivity analysis for the affordable, sustainable implementation of a global SOON calibration/validation network that can deliver the much-needed comprehensive, common, self-consistent operational picture in near-real time, at an affordable cost.

Lens-mount stability trade-off: a survey exemplified for DUV wafer inspection objectives

Science.gov (United States)

Bouazzam, Achmed; Erbe, Torsten; Fahr, Stephan; Werschnik, Jan

2015-09-01

The position stability of optical elements is an essential part of the tolerance budget of an optical system because its compensation would require an alignment step after the lens has left the factory. In order to achieve a given built performance the stability error contribution needs to be known and accounted for. Given a high-end lens touching the edge of technology not knowing, under- or overestimating this contribution becomes a serious cost and risk factor. If overestimated the remaining parts of the budget need to be tighter. If underestimated the total project might fail. For many mounting principles the stability benchmark is based on previous systems or information gathered by elaborated testing of complete optical systems. This renders the development of a new system into a risky endeavour, because these experiences are not sufficiently precise and tend to be not transferable when scaling of the optical elements is intended. This contribution discusses the influences of different optical mounting concepts on the position stability using the example of high numerical aperture (HNA) inspection lenses working in the deep ultraviolet (DUV) spectrum. A method to investigate the positional stability is presented for selected mounting examples typical for inspection lenses.

SU-F-P-11: Long Term Dosimetric Stability of 6 TomoTherapy Systems

Energy Technology Data Exchange (ETDEWEB)

Smilowitz, J; Dunkerley, D; Geurts, M; Hill, P; Yadav, P [University of Wisconsin, Madison, WI (United States)

2016-06-15

Purpose: The dosimetric stability of six TomoTherapy units was analyzed to investigate changes in performance over time and with system upgrades. Methods: Energy and output were tracked using monitor chamber signal, onboard MVCT detector signal and external ion chamber measurements. The systems (and monitoring periods) include 3 Hi-Art (67, 61 and 65 mos.), 2 HDA (29 and 25 mos.) and one research unit (7 mo.). Dose Control Stability system (DCS) was installed on 4 systems. Output stability is reported as deviation from reference monitor chamber signal for all systems, and from an external chamber for 4 systems. Energy stability was monitored using the relative (center versus off-axis) MVCT detector signal and/or the ratio of chamber measurements at 2 depths. The results from the clinical systems were used to benchmark the stability of the research unit, which has the same linear accelerator but runs at a higher dose rate. Results: The output based on monitor chamber data of all six systems is very stable. Non- DCS had a standard deviation of 1.7% and 1.8%. As expected, DCS systems had improved standard deviation: 0.003–0.05%. The energy was also very stable for all units. The standard deviation in exit detector flatness was 0.02–0.3%. Ion chamber output and 20/10 cm ratios supported these results. The stability for the research system, as monitored with a variety of metrics, is on par with the existing systems. Conclusion: The output and energy of six TomoTherapy units over a total of almost 10 years is quite stable. For each system, the results are consistent between the different measurement tools and techniques, proving not only the dosimetric stability, but that these quality parameters can be confirmed with various metrics. A research unit operating at a higher dose rate performed as well as the clinical treatment units. University of Wisconsin and Accuray Inc. (vendor of TomoTherapy systems) have a research agreement which supplies funds for research to

Direct reactions in inverse kinematics for nuclear structure studies far off stability at low incident energies

International Nuclear Information System (INIS)

Egelhof, P.

1997-02-01

The investigation of light-ion induced direct reactions with exotic beams in inverse kinematics gives access to a wide field of nuclear structure studies in the region far off stability. The present contribution will focus on the investigation of few-nucleon transfer reactions, which turn out to be most favourably studied with good-quality low-energy radioactive beams, as provided by the new generation of radioactive beam facilities presently planned or under construction at Caen, Grenoble, Munich, and elsewhere. An overview on the physics motivation, basically concerning nuclear structure and nuclear astrophysics questions, is given. Of particular interest are the nuclear shell model in the region far off stability, the two-body residual interaction in nuclei, the structure of halo nuclei, as well as the understanding of the r-process scenario. The experimental conditions, along with the experimental concept, for such measurements are discussed with particular emphasis on the kinematical conditions, the observables, as well as the appropriate detection schemes. The concept of a large solid angle TPC ionization chamber as an active target for experiments with low-energy radioactive beams is presented. It turns out to be a highly effective detection scheme, well suited for the present experimental conditions, at least for light exotic beams up to Z∼20. (orig.)

Applications of ZigBee Technology in the Safety Monitoring System of Low Gas Pipeline Transportation

Directory of Open Access Journals (Sweden)

Wei Deyu

2015-01-01

Full Text Available The existing safety monitoring system of low gas pipeline transportation establishes a wired communication network monitoring system mainly on the basis of industrial bus. It has problems such as large transmission signal attenuation, complex wiring, high-labor intensity, inconvenient installation and maintenance, high maintenance cost, and so on. Featuring low cost, power-saving, reliability, stability and flexibility, the wireless sensor network established by ZigBee wireless communication technology can realize the real-time all-dimensional dynamic monitoring on parameters of low gas pipeline transportation system and overcome the shortcomings and deficiencies of wired network system.

Preface: Workshop on Off-Grid Technology Systems

Science.gov (United States)

Alonso-Marroquin, Fernando

2017-06-01

Off-grid houses are dwellings that do not rely on water supply, sewer, or electrical power grid, and are able to operate independently of all public utility services. These houses are ideal for remote communities or population suffering natural or human-made disasters. Our aim is to develop compact and affordable off-grid technologies by integrating high-end nano-engineering with systems that imitates natural biological processes. The key areas of focus in the workshop were: solar energy harvesting using nanotechnology, wind energy harvesting from vertical-axis wind turbines, supercapacitors energy storage systems, treatment of greywater, and green roofs to achieve air comfort.

The Stability of CI02 as a Product of Gas Phase Decontamination Treatments

Energy Technology Data Exchange (ETDEWEB)

D. W. Simmons

1994-09-01

The gas phase decontamination project is investigating the use of chlorine trifluoride (ClF{sub 3}) to fluorinate nonvolatile uranium deposits to produce uranium hexafluoride (UF{sub 6}) gas. The potential existence of chlorine dioxide (ClO{sub 2}) during gas phase decontamination with ClF{sub 3} has been the subject of recent safety discussions. Some of the laboratory data collected during feasibility studies of the gas phase process has been evaluated for the presence of ClO{sub 2} in the product gas stream. The preliminary evidence to date can be summarized as follows: (1) ClO{sub 2} was not detected in the flow loop in the absence of ClF{sub 3}; (2) ClO{sub 2} was not detected in the static reactors in the absence of both ClF{sub 3} and ClF; and (3) ClO{sub 2} was detected in a static reactor in the absence of all fluorinating gases. The experimental evidence suggests that ClO{sub 2} will not exist in the presence of ClF{sub 3}, ClF, or UF{sub 6}. The data analyzed to date is insufficient to determine the stability of ClO{sub 2} in the presence of ClO{sub 2}F. Thermodynamic calculations of the ClF{sub 3} + H{sub 2}O system support the experimental evidence, and suggest that ClO{sub 2} will not exist in the presence of ClO{sub 2}F. Additional experimental efforts are needed to provide a better understanding of the gas phase ClF{sub 3} treatments and the product gases. However, preliminary evidence to date suggests that ClO{sub 2} should not be present as a product during the normal operations of the gas phase decontamination project.

Solar-gas systems impact analysis study

Science.gov (United States)

Neill, C. P.; Hahn, E. F.; Loose, J. C.; Poe, T. E.; Hirshberg, A. S.; Haas, S.; Preble, B.; Halpin, J.

1984-07-01

The impacts of solar/gas technologies on gas consumers and on gas utilities were measured separately and compared against the impacts of competing gas and electric systems in four climatic regions of the U.S. A methodology was developed for measuring the benefits or penalties of solar/gas systems on a combined basis for consumers sand distribution companies. It is shown that the combined benefits associated with solar/gas systems are generally greatest when the systems are purchased by customers who would have otherwise chosen high-efficiency electric systems (were solar/gas systems not available in the market place). The role of gas utilities in encouraging consumer acceptance of solar/gas systems was also examined ion a qualitative fashion. A decision framework for analyzing the type and level of utility involvement in solar/gas technologies was developed.

Stability problems for linear hyperbolic systems

International Nuclear Information System (INIS)

Eckhoff, K.S.

1975-05-01

The stability properties for the trivial solution of a general linear hyperbolic system of partial differential equations of the first order are studied. It is shown that results may be obtained by studying the stability properties of certain systems of ordinary differential equations which can be constructed from the hyperbolic system (the so-called transport equations). In some cases the associated stability problem for the transport equations can in fact be shown to be equivalent to the stability problem for the hyperbolic system, but in general the transport equations will only give the necessary conditions for stability. (Auth.)

On the thermodynamic stability of the generalized Chaplygin gas

International Nuclear Information System (INIS)

Santos, F.C.; Bedran, M.L.; Soares, V.

2006-01-01

The main purpose of this Letter is to discuss the temperature behavior and the thermodynamic stability of an exotic fluid known as generalized Chaplygin gas considering only general thermodynamics. This fluid is considered a perfect fluid which obeys an adiabatic equation of state like P=-A/ρ α , where P and ρ are respectively the pressure and energy density; the parameter A is a positive universal constant and α>0. It is remarked that if the energy density of the fluid is a function of volume only, the temperature of the fluid remains zero at any pressure or volume, violating the third law of thermodynamics. We have determined a scenario where its thermal equation of state depends on temperature only and the fluid presents thermodynamic stability during any expansion process. Such a scenario also reveals that the fluid cools down through the expansion without facing any critical point or phase transition

Numerical study of turbulent normal diffusion flame CH4-air stabilized by coaxial burner

Directory of Open Access Journals (Sweden)

Riahi Zouhair

2013-01-01

Full Text Available The practical combustion systems such as combustion furnaces, gas turbine, engines, etc. employ non-premixed combustion due to its better flame stability, safety, and wide operating range as compared to premixed combustion. The present numerical study characterizes the turbulent flame of methane-air in a coaxial burner in order to determine the effect of airflow on the distribution of temperature, on gas consumption and on the emission of NOx. The results in this study are obtained by simulation on FLUENT code. The results demonstrate the influence of different parameters on the flame structure, temperature distribution and gas emissions, such as turbulence, fuel jet velocity, air jet velocity, equivalence ratio and mixture fraction. The lift-off height for a fixed fuel jet velocity is observed to increase monotonically with air jet velocity. Temperature and NOx emission decrease of important values with the equivalence ratio, it is maximum about the unity.

Modified Schur-Cohn Criterion for Stability of Delayed Systems

Directory of Open Access Journals (Sweden)

Juan Ignacio Mulero-Martínez

2015-01-01

Full Text Available A modified Schur-Cohn criterion for time-delay linear time-invariant systems is derived. The classical Schur-Cohn criterion has two main drawbacks; namely, (i the dimension of the Schur-Cohn matrix generates some round-off errors eventually resulting in a polynomial of s with erroneous coefficients and (ii imaginary roots are very hard to detect when numerical errors creep in. In contrast to the classical Schur-Cohn criterion an alternative approach is proposed in this paper which is based on the application of triangular matrices over a polynomial ring in a similar way as in the Jury test of stability for discrete systems. The advantages of the proposed approach are that it halves the dimension of the polynomial and it only requires seeking real roots, making this modified criterion comparable to the Rekasius substitution criterion.

A bistriphenylamine-substituted spirobifluorene derivative exhibiting excellent nonlinearity/transparency/thermal stability trade-off and strong two-photon induced blue fluorescence

International Nuclear Information System (INIS)

Yin, Hongyao; Xiao, Haibo; Ding, Lei; Zhang, Chun; Ren, Aiming; Li, Bo

2015-01-01

A spirobifluorene-bridged donor/donor chromophore, 2,7-bis-(4-(N,N-diphenylamino)phen-1-yl)-9,9′-spirobifluorene (SPF-TP), was found to combine excellent transparency in the near UV–visible region (λ cut-off  ≤ 420 nm), large two-photon absorption cross-section (4.5 × 10 3 GM) and high thermal stability (T d  = 501 °C). In comparison to the reported two-photon absorption molecules, SPF-TP represents the best thermal stability so far described in the literature. The main electronic factors explaining the high two-photon absorption activities of SPF-TP were analyzed by theoretical calculations. Cyclic voltammograms were employed to explore the causes of the excellent transparency of SPF-TP. It was found that the spiroconjugation effect is responsible for the excellent nonlinearity/transparency/thermal stability trade-off in SPF-TP. In addition, SPF-TP is also a good two-photon induced blue fluorescent material with high fluorescence quantum yield (Φ = 0.90, in THF). - Highlights: • We report a molecule exhibiting excellent transparency. • The two-photon absorption cross-section is as large as 4.5 × 10 3 GM. • The molecule exhibits excellent thermal stability. • The molecule is a good two-photon induced blue fluorescent material. • The spiroconjugation effect explains the excellent properties

A bistriphenylamine-substituted spirobifluorene derivative exhibiting excellent nonlinearity/transparency/thermal stability trade-off and strong two-photon induced blue fluorescence

Energy Technology Data Exchange (ETDEWEB)

Yin, Hongyao [Department of Chemistry, Shanghai Normal University, Shanghai 200234 (China); Xiao, Haibo, E-mail: xiaohb@shnu.edu.cn [Department of Chemistry, Shanghai Normal University, Shanghai 200234 (China); Ding, Lei [Department of Chemistry, Shanghai Normal University, Shanghai 200234 (China); Zhang, Chun; Ren, Aiming [State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023 (China); Li, Bo [Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200241 (China)

2015-02-01

A spirobifluorene-bridged donor/donor chromophore, 2,7-bis-(4-(N,N-diphenylamino)phen-1-yl)-9,9′-spirobifluorene (SPF-TP), was found to combine excellent transparency in the near UV–visible region (λ{sub cut-off} ≤ 420 nm), large two-photon absorption cross-section (4.5 × 10{sup 3}GM) and high thermal stability (T{sub d} = 501 °C). In comparison to the reported two-photon absorption molecules, SPF-TP represents the best thermal stability so far described in the literature. The main electronic factors explaining the high two-photon absorption activities of SPF-TP were analyzed by theoretical calculations. Cyclic voltammograms were employed to explore the causes of the excellent transparency of SPF-TP. It was found that the spiroconjugation effect is responsible for the excellent nonlinearity/transparency/thermal stability trade-off in SPF-TP. In addition, SPF-TP is also a good two-photon induced blue fluorescent material with high fluorescence quantum yield (Φ = 0.90, in THF). - Highlights: • We report a molecule exhibiting excellent transparency. • The two-photon absorption cross-section is as large as 4.5 × 10{sup 3}GM. • The molecule exhibits excellent thermal stability. • The molecule is a good two-photon induced blue fluorescent material. • The spiroconjugation effect explains the excellent properties.

New stability and stabilization for switched neutral control systems

International Nuclear Information System (INIS)

Xiong Lianglin; Zhong Shouming; Ye Mao; Wu Shiliang

2009-01-01

This paper concerns stability and stabilization issues for switched neutral systems and presents new classes of piecewise Lyapunov functionals and multiple Lyapunov functionals, based on which, two new switching rules are introduced to stabilize the neutral systems. One switching rule is designed from the solution of the so-called Lyapunov-Metzler linear matrix inequalities. The other is based on the determination of average dwell time computed from a new class of linear matrix inequalities (LMIs). And then, state-feedback control is derived for the switched neutral control system mainly based on the state switching rules. Finally, three examples are given to demonstrate the effectiveness of the proposed method.

A MARTe based simulator for the JET Vertical Stabilization system

Energy Technology Data Exchange (ETDEWEB)

Bellizio, Teresa, E-mail: teresa.bellizio@unina.it [Associazione EURATOM-ENEA-CREATE, University di Napoli Federico II, Via Claudio 21, 80125 Napoli (Italy); De Tommasi, Gianmaria; Risoli, Nicola; Albanese, Raffaele [Associazione EURATOM-ENEA-CREATE, University di Napoli Federico II, Via Claudio 21, 80125 Napoli (Italy); Neto, Andre [Associacao EURATOM/IST, Inst. de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior, Tecnico, P-1049-001 Lisboa (Portugal)

2011-10-15

Validation by means of simulation is a crucial step when developing real-time control systems. Modeling and simulation are an essential tool since the early design phase, when the control algorithms are designed and tested. This phase is commonly carried out in off-line environments such as Matlab and Simulink. A MARTe-based simulator has been recently developed to validate the new JET Vertical Stabilization (VS) system. MARTe is the multi-thread framework used at JET to deploy hard real-time control systems. This paper presents the software architecture of the MARTe-based simulator and it shows how this tool has been effectively used to evaluate the effects of Edge Localized Modes (ELMs) on the VS system. By using the simulator it is possible to analyze different plasma configurations, extrapolating the limit of the new vertical amplifier in terms of the energy of the largest rejectable ELM.

An Untrodden Path: Versatile Fabrication of Self-Supporting Polymer-Stabilized Percolation Membranes (PSPMs) for Gas Separation.

Science.gov (United States)

Friebe, Sebastian; Mundstock, Alexander; Schneider, Daniel; Caro, Jürgen

2017-05-11

The preparation and scalability of zeolite or metal organic framework (MOF) membranes remains a major challenge, and thus prevents the application of these materials in large-scale gas separation. Additionally, several zeolite or MOF materials are quite difficult or nearly impossible to grow as defect-free layers, and require expensive macroporous ceramic or polymer supports. Here, we present new self-supporting zeolite and MOF composite membranes, called Polymer-Stabilized Percolation Membranes (PSPMs), consisting of a pressed gas selective percolation network (in our case ZIF-8, NaX and MIL-140) and a gas-impermeable infiltrated epoxy resin for cohesion. We demonstrate the performance of these PSPMs by separating binary mixtures of H 2 /CO 2 and H 2 /CH 4 . We report the brickwork-like architecture featuring selective percolation pathways and the polymer as a stabilizer, compare the mechanical stability of said membranes with competing materials, and give an outlook on how economic these membranes may become. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The development of a gas transmission system in Lebanon

Energy Technology Data Exchange (ETDEWEB)

Proudian, Serko; Rickaert, Stefan [Tractebel Engineering, Brussels (Belgium)

2005-07-01

Tractebel Engineering is undertaking for the Lebanese Ministry of Energy and Water (MEW) advisory services for the launching and for the awarding of a DBOT (Design, Build, Operate and Transfer) contract for the development of a gas transmission system through Lebanon. The service embraces a global approach, integrating legal, market, technical and financial matters, to provide MEW with a clear strategy to its gas development program, aimed at attracting private investors willing to tender on this DBOT project.The Legal Framework Report examines the existing Lebanese legal system and analyzes its suitability to the regulatory framework required to operate gas networks; it also provides recommendations aimed at attracting potential DBOT developers, by facilitating bureaucratic procedures with possible enactment of new laws. The Gas Demand Due Diligence Report provides the market study for present and future demand of gas in Lebanon in the next 25 years (duration of the DBOT contract), with anticipated needs resulting from power generation, industrial sector, commercial and residential sectors. The Pipeline Alternative Solutions Report provides several alternative routing and configurations for the gas transmission pipeline, including surveys, in-land routing (through rough mountain and heavily populated areas), or off-shore routing (through rough marine canyons and sea water depth in excess of 1,500 meters). Basic technical economical study is elaborated for more than 30 options.The Pipeline Financial Optimization Report compares the economics and provides for each solution the expected postal tariff (the compensation that MEW would need to pay to the developer for the execution of the 25 year DBOT contract). The advisory services are completed with preparation of the Pre-Qualification Notice (aimed at selecting a short list of qualified Bidders), preparation of the Request For Proposal (bidding on the selected pipeline option), evaluation of proposal, selection of

MEMBRANOUS FLOWS IN GAS-LIQUID COLLECTORS-REGENERATORS OF SOLAR ABSORPTIVE SYSTEMS FEATURES

Directory of Open Access Journals (Sweden)

Doroshenko А.V.

2009-12-01

Full Text Available Article is devoted to the creation of new generation of solar collectors of the gas-liquid type, intended for use in alternative refrigerating and conditioning systems of drying-evaporating type with direct solar regeneration of absorbent. Special attention is given to the study of membranous flows features on inclined surfaces, including questions of such flows stability.

First-principles study of noble gas stability in ThO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Shao, Kuan [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Han, Han, E-mail: hanhanfudan@gmail.com [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Zhang, Wei [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Key Laboratory of Interfacial Physics and Technology, Chinese Academy of Sciences, Shanghai 201800 (China); Wang, Hui [School of Physics and Engineering, Henan University of Science and Technology, Luoyang 471003 (China); Wang, Chang-Ying; Guo, Yong-Liang [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Ren, Cui-Lan [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Key Laboratory of Interfacial Physics and Technology, Chinese Academy of Sciences, Shanghai 201800 (China); Huai, Ping, E-mail: huaiping@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)

2017-07-15

The stability of noble gases (He, Ne, Ar, Kr and Xe) in thorium dioxide is studied by means of density functional theory. The computations are performed considering insertion sites of ThO{sub 2}, including the interstitial sites, the thorium vacancies, the oxygen-thorium di-vacancy and three types of Schottky defects. Our results show that there is an approximately linear relation between the energies and the atomic radii. As the size of the noble gas atom increases, the noble gas atoms energetically prefer to incorporate into large vacancy defects rather than into interstitial positions. Moreover, the binding energy of Kr or Xe interstitial in a Schottky defect is larger than the formation energy of a Schottky defect, suggesting the Schottky defects are thermodynamically favorable in the presence of these noble gas atoms. The charged defects are also considered for noble gas atoms trapped in Th and O vacancies.

Stability of dynamical systems

CERN Document Server

Liao, Xiaoxin; Yu, P 0

2007-01-01

The main purpose of developing stability theory is to examine dynamic responses of a system to disturbances as the time approaches infinity. It has been and still is the object of intense investigations due to its intrinsic interest and its relevance to all practical systems in engineering, finance, natural science and social science. This monograph provides some state-of-the-art expositions of major advances in fundamental stability theories and methods for dynamic systems of ODE and DDE types and in limit cycle, normal form and Hopf bifurcation control of nonlinear dynamic systems.ʺ Presents

Controls on methane expulsion during melting of natural gas hydrate systems. Topic area 2

Energy Technology Data Exchange (ETDEWEB)

Flemings, Peter [Univ. of Texas, Austin, TX (United States)

2016-01-14

1.1. Project Goal The project goal is to predict, given characteristic climate-induced temperature change scenarios, the conditions under which gas will be expelled from existing accumulations of gas hydrate into the shallow ocean or directly to the atmosphere. When those conditions are met, the fraction of the gas accumulation that escapes and the rate of escape shall be quantified. The predictions shall be applicable in Arctic regions and in gas hydrate systems at the up dip limit of the stability zone on continental margins. The behavior shall be explored in response to two warming scenarios: longer term change due to sea level rise (e.g. 20 thousand years) and shorter term due to atmospheric warming by anthropogenic forcing (decadal time scale). 1.2. Project Objectives During the first budget period, the objectives are to review and categorize the stability state of existing well-studied hydrate reservoirs, develop conceptual and numerical models of the melting process, and to design and conduct laboratory experiments that dissociate methane hydrate in a model sediment column by systematically controlling the temperature profile along the column. The final objective of the first budget period shall be to validate the models against the experiments. In the second budget period, the objectives are to develop a model of gas flow into sediment in which hydrate is thermodynamically stable, and conduct laboratory experiments of this process to validate the model. The developed models shall be used to quantify the rate and volume of gas that escapes from dissociating hydrate accumulations. In addition, specific scaled simulations characteristic of Arctic regions and regions near the stability limit at continental margins shall be performed. 1.3. Project Background and Rationale The central hypothesis proposed is that hydrate melting (dissociation) due to climate change generates free gas that can, under certain conditions, propagate through the gas hydrate stability

Collimator system for the stabilization of the dynamical residual-gas pressure in the heavy-ion synchrotron SIS18; Kollimatorsystem zur Stabilisierung des dynamischen Restgasdruckes im Schwerionensynchrotron SIS18

Energy Technology Data Exchange (ETDEWEB)

Omet, Carsten

2009-01-15

In order to achieve higher beam intensities of heavy ion beams in ring accelerators, low charge state ions can be used. By lowering the charge state, the space charge limit is shifted to higher particle numbers and stripping losses can be avoided. During test operation of the SIS18 at GSI with high intensity low charge state heavy ion beams, strong intensity dependent beam losses have been observed. It was found that these beam losses are originated to a large extent by the change of charge state of the circulating ions during collisions with residual gas atoms. The resulting deviation of m/q relative to the reference ion leads, in combination with dispersive elements in the ion optic lattice, to a modified trajectory, followed by the loss of the ion on the beam pipe. At the impact position, loosely bound residual gas molecules are released by ion stimulated desorption which increases the residual gas pressure locally. This pressure rise itself enhances the charge exchange rate, which can develop into a self amplifying process of pressure rise and subsequent beam loss. A method for the stabilization of the dynamic residual gas pressure is the use of special catcher systems, which minimize the production of desorption gases and remove them by strong pumping. Therefore, the pressure on the beam axis should remain as stable as possible. Other processes, e.g. Coulomb scattering of the beam ions by residual gas particles and unavoidable systematic beam losses can increase the gas pressure additionally. The pressure in the accelerator is further subjected to ionization of the residual gas atoms themselves, thermal out gassing of the beam pipes, insertions and pumps. In this work, a detailed numerical model of the interplay between the residual gas pressure dynamics in the accelerator, possible stabilization measures, e.g. by catchers and the resulting beam life time has been developed. The forecasted beam life times and pressures are verified by machine experiments, as

In situ high-temperature gas sensors: continuous monitoring of the combustion quality of different wood combustion systems and optimization of combustion process

Directory of Open Access Journals (Sweden)

H. Kohler

2018-03-01

Full Text Available The sensing characteristics and long-term stability of different kinds of CO ∕ HC gas sensors (non-Nernstian mixed potential type during in situ operation in flue gas from different types of low-power combustion systems (wood-log- and wood-chip-fuelled were investigated. The sensors showed representative but individual sensing behaviour with respect to characteristically varying flue gas composition over the combustion process. The long-term sensor signal stability evaluated by repeated exposure to CO ∕ H2 ∕ N2 ∕ synthetic air mixtures showed no sensitivity loss after operation in the flue gas. Particularly for one of the sensors (Heraeus GmbH, this high signal stability was observed in a field test experiment even during continuous operation in the flue gas of the wood-chip firing system over 4 months. Furthermore, it was experimentally shown that the signals of these CO ∕ HC sensing elements yield important additional information about the wood combustion process. This was demonstrated by the adaptation of an advanced combustion airstream control algorithm on a wood-log-fed fireplace and by the development of a combustion quality monitoring system for wood-chip-fed central heaters.

Stabilized imploding liner fusion systems

International Nuclear Information System (INIS)

Book, D.L.; Cooper, A.L.; Ford, R.; Gerber, K.A.; Hammer, D.A.; Jenkins, D.J.; Robson, A.E.; Turchi, P.J.

1977-01-01

A new concept in imploding liner plasma compression is described in which a liquid metal liner is imploded by pistons driven by high-pressure gas, and stability of the inner surface against Rayleigh-Taylor modes is achieved by rotation. The principle has been demonstrated by using a water liner to compress air. This 'captive liner' offers the possibility of stable, reversible implosion-expansion cycles in which the plasma energy is recovered into the driving system, leading to reactor cycles with low Q and, hence, small size. A new method of setting up closed-field confinement geometries inside a liner using a rotating electron beam is described. Plasma currents induced by the beam provide initial plasma heating and generate the containment geometry. Persistence of plasma currents 100 times longer than the beam duration has been observed. Development of these methods could lead to a very compact thermonuclear reactor operating in the manner of a reciprocating engine. (author)

LHCB RICH gas system proposal

CERN Document Server

Bosteels, Michel; Haider, S

2001-01-01

Both LHCb RICH will be operated with fluorocarbon as gas radiator. RICH 1 will be filled with 4m^3 of C4F10 and RICH 2 with 100m^3 of CF4. The gas systems will run as a closed loop circulation and a gas recovery system within the closed loop is planned for RICH 1, where the recovery of the CF4 will only be realised during filling and emptying of the detector. Inline gas purification is foreseen for the gas systems in order to limit water and oxygen impurities.

Integrating Robot Task Planning into Off-Line Programming Systems

DEFF Research Database (Denmark)

Sun, Hongyan; Kroszynski, Uri

1988-01-01

a system architecture for integrated robot task planning. It identifies and describes the components considered necessary for implementation. The focus is on functionality of these elements as well as on the information flow. A pilot implementation of such an integrated system architecture for a robot......The addition of robot task planning in off-line programming systems aims at improving the capability of current state-of-the-art commercially available off-line programming systems, by integrating modeling, task planning, programming and simulation together under one platform. This article proposes...... assembly task is discussed....

Dynamic Stability of Maglev Systems,

Science.gov (United States)

1992-04-01

AD-A259 178 ANL-92/21 Materials and Components Dynamic Stability of Technology Division Materials and Components Maglev Systems Technology Division...of Maglev Systems Y. Cai, S. S. Chen, and T. M. Mulcahy Materials and Components Technology Division D. M. Rote Center for Transportation Research...of Maglev System with L-Shaped Guideway ......................................... 6 3 Stability of M aglev System s

arXiv Simulation of gain stability of THGEM gas-avalanche particle detectors

CERN Document Server

Correia, P.M.M.; Azevedo, C.D.R.; Breskin, A.; Bressler, S.; Oliveira, C.A.B.; Silva, A.L.M.; Veenhof, R.; Veloso, J.F.C.A.

2018-01-19

Charging-up processes affecting gain stability in Thick Gas Electron Multipliers (THGEM) were studied with a dedicated simulation toolkit. Integrated with Garfield++, it provides an effective platform for systematic phenomenological studies of charging-up processes in MPGD detectors. We describe the simulation tool and the fine-tuning of the step-size required for the algorithm convergence, in relation to physical parameters. Simulation results of gain stability over time in THGEM detectors are presented, exploring the role of electrode-thickness and applied voltage on its evolution. The results show that the total amount of irradiated charge through electrode's hole needed for reaching gain stabilization is in the range of tens to hundreds of pC, depending on the detector geometry and operational voltage. These results are in agreement with experimental observations presented previously.

Worcester 1 Inch Solenoid-Actuated Gas Operated SCHe System Valves

International Nuclear Information System (INIS)

VAN KATWIJK, C.

2000-01-01

1 inch Gas-operated full-port ball valves incorporate a solenoid and limit switches as integral parts of the actuator. These valves are normally open and fail safe to the open position (GOV-1*02 and 1*06 fail closed) to provide a flow path of helium gas to the MCO under helium purge and off-normal conditions when the MCO is isolated

Hybrid Off-Grid SPV/WTG Power System for Remote Cellular Base Stations Towards Green and Sustainable Cellular Networks in South Korea

Directory of Open Access Journals (Sweden)

Mohammed H. Alsharif

2016-12-01

Full Text Available This paper aims to address the sustainability of power resources and environmental conditions for telecommunication base stations (BSs at off-grid sites. Accordingly, this study examined the feasibility of using a hybrid solar photovoltaic (SPV/wind turbine generator (WTG system to feed the remote Long Term Evolution-macro base stations at off-grid sites of South Korea the energy necessary to minimise both the operational expenditure and greenhouse gas emissions. Three key aspects have been discussed: (i optimal system architecture; (ii energy yield analysis; and (iii economic analysis. In addition, this study compares the feasibility of using a hybrid SPV/WTG system vs. a diesel generator. The simulation results show that by applying the proposed SPV/WTG system scheme to the cellular system, the total operational expenditure can be up to 48.52% more efficient and sustainability can be ensured with better planning by providing cleaner energy.

Adequate Measuring Technology and System of Fission Gas release Behavior from Voloxidation Process

International Nuclear Information System (INIS)

Park, Geun Il; Park, J. J.; Jung, I. H.; Shin, J. M.; Yang, M. S.; Song, K. C.

2006-09-01

Based on the published literature and an understanding of available hot cell technologies, more accurate measuring methods for each volatile fission product released from voloxidation process were reviewed and selected. The conceptual design of an apparatus for measuring volatile and/or semi-volatile fission products released from spent fuel was prepared. It was identified that on-line measurement techniques can be applied for gamma-emitting fission products, and off-line measurement such as chemical/or neutron activation analysis can applied for analyzing beta-emitting fission gases. Collection methods using appropriate material or solutions were selected to measure the release fraction of beta-emitting gaseous fission products at IMEF M6 hot cell. Especially, the on-line gamma-ray counting system for monitoring of 85Kr and the off-line measuring system of 14C was established. On-line measuring system for obtaining removal ratios of the semi-volatile fission products, mainly gamma-emitting fission products such as Cs, Ru etc., was also developed at IMEF M6 hot cell which was based on by measuring fuel inventory before and after the voloxidation test through gamma measuring technique. The development of this measurement system may enable basic information to be obtained to support design of the off-gas treatment system for the voloxidation process at INL, USA

Off-gas chemistry study of melter feed by Springborn Laboratories

International Nuclear Information System (INIS)

Crow, K.R.

1985-01-01

The purpose of the off-gas chemistry study of melter feed samples was to support and help substantiate glass melter thermochemistry models developed for the DWPF. Both sludge-only and sludge-precipitate feed samples were analyzed. Each slurry sample was pyrolyzed at temperatures from 150 to 1000 0 C in air and inert atmospheres, and the head space products were analyzed by chromatographic and mass spectrometric methods. Thermogravimetric, differential scanning calorimetric and Fourier transform infrared analyses were also performed on each sample. There were no unusually high exothermic reactions that would be cause for concern in the DWPF melter. Results for two types of sludge-precipitate feed were compared. One type contained simulated precipitate hydrolysis aqueous (PHA) product as fed to the SCM-2 melter. The second type contained PHA from the lab-scale acid hydrolysis reactor in 677-T. A major difference between the two types was a small, but distinct, presence of higher aromatics in gas from feed with reactor-produced PHA. This feed also evolved more CO and CO 2 than feed with simulated PHA at high pyrolytic temperatures (>750 0 C). Recent analyses have identified the higher boiling aromatics in reactor-produced PHA as primarily diphenylamine and p-terphenyl. These compounds will be included in future PHA simulations that are fed to research melters. Under an inert atmosphere, benzene and phenol were the two most abundant organics evolved during pyrolysis of sludge-precipitate feed

Blow-off of hydrogen using an optimized design of discharge jet-mixer arrangement

International Nuclear Information System (INIS)

Ristow, Torsten

2011-01-01

Hydrogen is ignitable in air at volume concentrations between 4 % and 75 %. Therefore, in the case of an emergency evacuation of a hydrogen-cooled generator in nuclear power plants, the gas has to be safely blown-off above the turbine building. Especially, a leakage at the hydrogen containing piping system at the generator has gained more and more importance in the context of safety assessments. The design of a blow-off system respects two safety aspects: Firstly, a short blow-off time is necessary to reduce the hydrogen release inside the turbine building in case of a leakage. Secondly, for the postulated ignition of the released hydrogen on the roof of the building the resulting pressure load must remain below the maximum admissible one of the turbine building roof. In order to fulfill the first condition an appropriate fast evacuation piping system from the generator to the blow-off outlet is designed. Regarding the latter the blow-off system uses special discharge nozzles placed horizontally in a radial-symmetric configuration. In this respect, the influence of strong wind conditions during the evacuation process is also considered. The resulting ignitable volume of the overlapping H2-air clouds does not exceed the maximum allowed ignitable volume. In the following the underlying process of blow-off by a fast hydrogen evacuation system is discussed. First the transient general blow-off behavior in the dedicated piping system is analyzed with the fluid piping tool ROLAST. The results of these calculations are boundary conditions for the subsequent qualification of the blow-off jet-mixer. Here a proof of the general functionality is given (2D CFD). Subsequently the blow-off behavior of the H2-air mixture is discussed in independent 3D CFD calculations with and without wind. From these analyses the possible ignitable gas volumes are determined. Final step is a simplified semi-analytical assessment of the resulting possible deflagration loads on the civil structure

Controlling the position of a stabilized detonation wave in a supersonic gas mixture flow in a plane channel

Science.gov (United States)

Levin, V. A.; Zhuravskaya, T. A.

2017-03-01

Stabilization of a detonation wave in a stoichiometric hydrogen-air mixture flowing at a supersonic velocity into a plane symmetric channel with constriction has been studied in the framework of a detailed kinetic mechanism of the chemical interaction. Conditions ensuring the formation of a thrust-producing f low with a stabilized detonation wave in the channel are determined. The inf luence of the inf low Mach number, dustiness of the combustible gas mixture supplied to the channel, and output cross-section size on the position of a stabilized detonation wave in the f low has been analyzed with a view to increasing the efficiency of detonation combustion of the gas mixture. It is established that thrust-producing flow with a stabilized detonation wave can be formed in the channel without any energy consumption.

A proposal for off-grid photovoltaic systems with non-controllable loads using fuzzy logic

International Nuclear Information System (INIS)

Yahyaoui, Imene; Sallem, Souhir; Kamoun, M.B.A.; Tadeo, Fernando

2014-01-01

Highlights: • An energy management system is proposed for off-grid PV systems, based on fuzzy logic. • The proposal guarantees the energy balance and battery protection. • The approach is demonstrated using data measured at the target location. - Abstract: A fuzzy-logic based methodology is proposed and evaluated for energy management in off-grid installations with photovoltaic panels as the source of energy and a limited storage capacity in batteries. The decision on the connection or disconnection of components is based on fuzzy rules on the basis of the Photovoltaic Panel Generation measurement, the measured power required by the load, and the estimation of the stored energy in the batteries (this last is obtained from the estimation of the Depth-of-Discharge). The algorithm aims to ensure the system’s autonomy by controlling the switches linking the system components with respect to a multi-objective management criterion developed from the requirements (supply of the load, protection of the battery, etc.). Detailed tests of the proposed system are carried out using data (irradiation, temperature, power consumption, etc.) measured in a household at the target area at several days of the year. The results demonstrate that the proposed approach achieves the objectives of system autonomy, battery protection and power supply stability. Compared with a basic algorithm, the proposed algorithm is not sensitive to sudden changes in atmospheric parameters and avoids overcharging the battery

System identification on two-phase flow stability

International Nuclear Information System (INIS)

Wu Shaorong; Zhang Youjie; Wang Dazhong; Bo Jinghai; Wang Fei

1996-01-01

The theoretical principle, experimental method and results of interrelation analysis identification for the instability of two-phase flow are described. A completely new concept of test technology and method on two-phase flow stability was developed by using he theory of information science on system stability and system identification for two-phase flow stability in thermo-physics field. Application of this method would make it possible to identify instability boundary of two-phase flow under stable operation conditions of two-phase flow system. The experiment was carried out on the thermohydraulic test system HRTL-5. Using reverse repeated pseudo-random sequences of heating power as input signal sources and flow rate as response function in the test, the two-phase flow stability and stability margin of the natural circulation system are investigated. The effectiveness and feasibility of identifying two-phase flow stability by using this system identification method were experimentally demonstrated. Basic data required for mathematics modeling of two-phase flow and analysis of two-phase flow stability were obtained, which are useful for analyzing, monitoring of the system operation condition, and forecasting of two-phase flow stability in engineering system

Characterization and calibration of gas sensor systems at ppb level—a versatile test gas generation system

Science.gov (United States)

Leidinger, Martin; Schultealbert, Caroline; Neu, Julian; Schütze, Andreas; Sauerwald, Tilman

2018-01-01

This article presents a test gas generation system designed to generate ppb level gas concentrations from gas cylinders. The focus is on permanent gases and volatile organic compounds (VOCs) for applications like indoor and outdoor air quality monitoring or breath analysis. In the design and the setup of the system, several issues regarding handling of trace gas concentrations have been considered, addressed and tested. This concerns not only the active fluidic components (flow controllers, valves), which have been chosen specifically for the task, but also the design of the fluidic tubing regarding dead volumes and delay times, which have been simulated for the chosen setup. Different tubing materials have been tested for their adsorption/desorption characteristics regarding naphthalene, a highly relevant gas for indoor air quality monitoring, which has generated high gas exchange times in a previous gas mixing system due to long time adsorption/desorption effects. Residual gas contaminations of the system and the selected carrier air supply have been detected and quantified using both an analytical method (GC-MS analysis according to ISO 16000-6) and a metal oxide semiconductor gas sensor, which detected a maximum contamination equivalent to 28 ppb of carbon monoxide. A measurement strategy for suppressing even this contamination has been devised, which allows the system to be used for gas sensor and gas sensor system characterization and calibration in the low ppb concentration range.

Off-gas monitor system for the detection of a failed fuel cladding tube

International Nuclear Information System (INIS)

Yuasa, Yoshiyuki; Oosaki, Masahiko; Naito, Makoto.

1984-01-01

Purpose: To rapidly and reliably detect failures in a fuel cladding tube thereby prevent accidents. Method: Off-gases discharged from an air extractor are mixed at a certain ratio with cleaning water and gamma spectra for short-life radioactive rare gases and for long-life radioactive rare gases in the off-gases are measured by gamma ray detectors. The spectra are analyzed by a Pulse-height analyzer so as to quantitatively determine the nuclides of radioactive rare gases thereby calculate the release rate on each of the nuclides. Further, a central data-processing unit calculates the composition ratio of each release models about recoil, diffusion and equilibrium in the whole radioactive rare gases based on the release rate. As the total value of the release rate is rapidly increased, recoil part will be decreased suddenly and the diffusion and equilibrium parts will be increased by so much, upon failure of a fuel can; thus the failure can rapidly be detected. (Sekiya, K.)

Efficient common rail injection systems and intelligent control strategies for the fulfillment of future on/off highway emission limits; Effiziente Common Rail Einspritzsysteme und intelligente Regelstrategien fuer die Erfuellung zukuenftiger On-/Off-Highway Emissionsgrenzwerte

Energy Technology Data Exchange (ETDEWEB)

Schugger, Christian; Krauss, Jost; Projahn, Ulrich; Gerhardt, Juergen [Robert Bosch GmbH, Stuttgart-Feuerbach (Germany)

2011-07-01

The diesel engine is the most common powertrain in commercial applications, and will retain that position for the foreseeable future. In order to meet future emission standards, a wide variety of solutions within combustion process control, exhaust gas aftertreatment, air and injection systems have been developed. The development of common rail injection systems for trucks with 2000 and 2200 bar injection pressure increases the opportunities for internal engine emissions reductions. The systems are designed for medium-duty and heavy-duty applications, on-highway (on-HW) and Off-highway (off-HW). Besides increasing the injection pressure this system features high efficiency in hydraulic pressure generation and injection, making a direct contribution to reducing fuel consumption. To meet even greater requirements, a system with an injection pressure of 2500 bar is under development. As an indicator for the hydraulic efficiency of an injector, the ''effective injection pressure'' is derived. This indicator allows for a uniform rating of different injector concepts. Software functions contribute to the fulfillment of the system requirements over lifetime. An engine speed based function calibrates the pilot injection quantity during low idle operation for on- and off-highway applications. The increase in system pressure results in increased loads for the components. A calibration function for the pump delivery characteristics minimizes pressure overshoots and ensures the pressure control dynamics over lifetime. (orig.)

Daya Bay Antineutrino Detector gas system

Science.gov (United States)

Band, H. R.; Cherwinka, J. J.; Chu, M.-C.; Heeger, K. M.; Kwok, M. W.; Shih, K.; Wise, T.; Xiao, Q.

2012-11-01

The Daya Bay Antineutrino Detector gas system is designed to protect the liquid scintillator targets of the antineutrino detectors against degradation and contamination from exposure to ambient laboratory air. The gas system is also used to monitor the leak tightness of the antineutrino detector assembly. The cover gas system constantly flushes the gas volumes above the liquid scintillator with dry nitrogen to minimize oxidation of the scintillator over the five year lifetime of the experiment. This constant flush also prevents the infiltration of radon or other contaminants into these detecting liquids keeping the internal backgrounds low. Since the Daya Bay antineutrino detectors are immersed in the large water pools of the muon veto system, other gas volumes are needed to protect vital detector cables or gas lines. These volumes are also purged with dry gas. Return gas is monitored for oxygen content and humidity to provide early warning of potentially damaging leaks. The design and performance of the Daya Bay Antineutrino Detector gas system is described.

Off-line programming (OLP) system comparison

International Nuclear Information System (INIS)

Holliday, M.A.

1993-01-01

Off-line programming (OLP) systems are being used to conceptualize, design, simulate, and now control automated robotic workcells. Currently available systems by Deneb, SILMA, and Cimetrix are being used at the Lawrenece Livermore National Laboratory (LLNL) to simulate and control automated robotic systems for radioactive material processing and hazardous waste sorting. The differences in system architectures, workcell and robot calibration procedures, operator interface, and graphical output capability of each will be discussed. The relative strengths and weaknesses of these attributes will be discussed as they relate to varying applications in robotic workcell development and control

Stabilizing effect of gas conductivity evolution on the resistive sausage mode of a propagating beam

International Nuclear Information System (INIS)

Lampe, M.; Joyce, G.

1983-01-01

Previous theoretical work has shown that a highly current-neutralized charged particle beam propagating in a preionized plasma channel of fixed conductivity is subject to a resistive sausage instability. It is shown that the instability is stabilized, for the case of beam propagation into an initially un-ionized gas, when the effect of beam-collisional ionization on the gas conductivity is modeled fully self-consistently

Gas Migration Processes through the Gas Hydrate Stability Zone at Four-Way Closure Ridge Offshore SW Taiwan

Science.gov (United States)

Kunath, P.; Chi, W. C.; Berndt, C.; Liu, C. S.

2016-12-01

We have used 3D P-Cable seismic data from Four-Way-Closure Ridge, a NW-SE trending anticlinal ridge within the lower slope domain of accretionary wedge, to investigate the geological constraints influencing the fluid migration pattern in the shallow marine sediments. In the seismic data, fluid migration feature manifests itself as high reflection layers of dipping strata, which originate underneath a bottom simulating reflector (BSR) and extend towards the seafloor. Shoaling of the BSR near fluid migration pathways indicates a focused fluid flux, perturbing the temperature field. Furthermore, seafloor video footage confirmed the presence of recent methane seepage above seismically imaged fluid migration pathways. We plan to test two hypotheses for the occurrence of these fluid migration pathways: 1) the extensional regime under the anticlinal ridge crest caused the initiation of localized fault zones, acting as fluid conduits in the gas hydrate stability zone (GHSZ). 2) sediment deformation induced by focused fluid flow and massive growth and dissolution of gas hydrate, similar to processes controlling the evolution of pockmarks on the Nigerian continental margin. We suggest that these processes may be responsible for the formation of a massive hydrate core in the crest of the anticline, as inferred from other geophysical datasets. Triggering process for fluid migration cannot be clearly defined. However, the existence of blind thrust faults may help to advect deep-seated fluids. This may be augmented by biogenic production of shallow gas underneath the ridge, where the excess of gas enables the coexistence of gas, water, and gas hydrate within the GHSZ. Fluid migration structures may exists because of the buoyancy of gas-bearing fluids. This study shows a potential model on how gas-bearing fluids migrate upward towards structural highs, which might occur in other anticlinal structures around the world. Keywords: P-Cable, gas-hydrate, fluid flow, fault-related fold

Approximate entropy—a new statistic to quantify arc and welding process stability in short-circuiting gas metal arc welding

International Nuclear Information System (INIS)

Cao Biao; Xiang Yuanpeng; Lü Xiaoqing; Zeng Min; Huang Shisheng

2008-01-01

Based on the phase state reconstruction of welding current in short-circuiting gas metal arc welding using carbon dioxide as shielding gas, the approximate entropy of welding current as well as its standard deviation has been calculated and analysed to investigate their relation with the stability of electric arc and welding process. The extensive experimental and calculated results show that the approximate entropy of welding current is significantly and positively correlated with arc and welding process stability, whereas its standard deviation is correlated with them negatively. A larger approximate entropy and a smaller standard deviation imply a more stable arc and welding process, and vice versa. As a result, the approximate entropy of welding current promises well in assessing and quantifying the stability of electric arc and welding process in short-circuiting gas metal arc welding

Stability improvement of wind turbine penetrated using power system stabilizer (PSS) on South Sulawesi transmission system

Science.gov (United States)

Siswanto, Agus; Gunadin, Indar Chaerah; Said, Sri Mawar; Suyuti, Ansar

2018-03-01

The purpose of this research is to improve the stability of interconnection of South Sulawesi system caused by penetration new wind turbine in Sidrap area on bus 2 and in Jeniponto area on bus 34. The method used in this research was via software Power System analysis Toolbox (PSAT) under MATLAB. In this research, there are two problems that are evaluated, the stability of the system before and after penetration wind turbine into the system South Sulawesi system. From the simulation result shows that penetration of wind turbine on bus 2 Sidrap, bus 37 Jeniponto give effect oscillation on the system. The oscillation was damped by installation of Power System Stabilizer (PSS) on bus 29 area Sungguminasa, that South Sulawesi system stable according to normal condition.

Stability of test environments for performance evaluation of materials for the modular high-temperature gas-cooled reactor

International Nuclear Information System (INIS)

Edgemon, G.L.; Wilson, D.F.; Bell, G.E.C.

1993-01-01

Stability of the primary helium-based coolant test gas for use in performance ests of materials for the Modular High-Temperature Gas-Cooled Reactor (MHTGR) was determined. Results of tests of the initial gas chemistry from General Atomics (GA) at elevated temperatures, and the associated results predicted by the SOLGASMIX trademark modelling package are presented. Results indicated that for this gas composition and at flow rates obtainable in the test loop, 466 ± 24C is the highest temperature that can be maintained without significantly altering the specified gas chemistry. Four additional gas chemistries were modelled using SOLGASMIX trademark

Closed-cycle gas turbine power generating system

International Nuclear Information System (INIS)

Jubb, A.; Ward, R.G.; Hurst, J.N.; Holliday, J.B.; Ashley, J.W.

1975-01-01

The invention deals with a gas-cooled reactor with at least one condenser, one turbin and one off-gas heat exchanger for preheating the coolant arranged in the pressure vessel inside a common supporting structure in the from of a pipe cylinder. This supporting structure can be removed from the pressure vessel independently of the core. The pipe cylinder is connected with the core feeding and recirculation lines. It has axial coolant channels in the cylindrical wall. The heat exchanger consists of a large number of coolant channels in axial direction. The feeding line is surrounded by several interpenetrating elastic ring elements. (HP) [de

46 CFR 121.240 - Gas systems.

Science.gov (United States)

2010-10-01

... gas (LPG) and compressed natural gas (CNG) must meet the following requirements: (a) The design, installation and testing of each LPG system must meet ABYC A-1, “Marine Liquefied Petroleum Gas (LPG) Systems... 46 Shipping 4 2010-10-01 2010-10-01 false Gas systems. 121.240 Section 121.240 Shipping COAST...

Natural gas reburning technology for NOx reduction from MSW combustion systems

International Nuclear Information System (INIS)

Penterson, C.A.; Abbasi, H.; Khinkis, M.J.; Wakamura, Y.; Linz, D.G.

1990-01-01

A technology for reducing emissions from municipal solid waste combustion systems through advanced combustion techniques is being developed. Pilot testing of natural gas reburning was first performed in the Institute of Gas Technology's pilot-scale furnace under conditions simulating the firing of 1.7 x 10 6 Btu/hr (0.5 MWth) of MSW. Pilot testing then continued in Riley Stoker Corporation's 3 x 10 6 Btu/hr (0.88 MWth), 7 ton/day, pilot-scale MSW combustor using actual MSW in both test series, injection of up to 15% (HHV basis) natural gas reduced NO, by 50--70% while maintaining or improving combustion efficiency as measured by CO and hydrocarbon emissions and temperature stability. This paper will review the test results and discuss the status of the full-scale field demonstration testing that is planned for 1990

Plutonium stabilization and packaging system

International Nuclear Information System (INIS)

1996-01-01

This document describes the functional design of the Plutonium Stabilization and Packaging System (Pu SPS). The objective of this system is to stabilize and package plutonium metals and oxides of greater than 50% wt, as well as other selected isotopes, in accordance with the requirements of the DOE standard for safe storage of these materials for 50 years. This system will support completion of stabilization and packaging campaigns of the inventory at a number of affected sites before the year 2002. The package will be standard for all sites and will provide a minimum of two uncontaminated, organics free confinement barriers for the packaged material

Probabilistic stability analysis: the way forward for stability analysis of sustainable power systems.

Science.gov (United States)

Milanović, Jovica V

2017-08-13

Future power systems will be significantly different compared with their present states. They will be characterized by an unprecedented mix of a wide range of electricity generation and transmission technologies, as well as responsive and highly flexible demand and storage devices with significant temporal and spatial uncertainty. The importance of probabilistic approaches towards power system stability analysis, as a subsection of power system studies routinely carried out by power system operators, has been highlighted in previous research. However, it may not be feasible (or even possible) to accurately model all of the uncertainties that exist within a power system. This paper describes for the first time an integral approach to probabilistic stability analysis of power systems, including small and large angular stability and frequency stability. It provides guidance for handling uncertainties in power system stability studies and some illustrative examples of the most recent results of probabilistic stability analysis of uncertain power systems.This article is part of the themed issue 'Energy management: flexibility, risk and optimization'. © 2017 The Author(s).

The recovery of waste and off-gas in Large Combustion Plants subject to IPPC National Permit in Italy.

Science.gov (United States)

Di Marco, Giuseppe; Manuzzi, Raffaella

2018-03-01

The recovery of off-gas, waste, and biomass in Large Combustion Plants for energy production gives the opportunity to recycle waste and by-products and to recover materials produced in agricultural and industrial activities. The paper illustrates the Italian situation regarding the production of energy from off-gas, biomass, and waste in Large Combustion Plants subject to Integrated Pollution Prevention and Control (IPPC) National Permit. Moreover, it focuses on the 4 Italian Large Combustion Plants producing energy from biomass and waste. For these ones it illustrates the specific issues related to and provides a description of the solutions adopted in the 4 Italian plants. Given that air emission performance is the most relevant aspect of this kind of plants, the paper specifically focuses and reports results about this subject. In particular, in Italy among 113 LCPs subject to IPPC National Permit we have found that 4 plants use as fuel waste (i.e. solid or liquid biomasses and Solid Recovered Fuels), or a mixture of waste and traditional fuels (co-combustion of Solid Recovered Fuels and coal), and that 11 plants use as fuel off-gases listed in Annex X (i.e. Refinery Fuel Gas, Syngas, and gases produced in iron and steel industries). Moreover, there are 2 IPPC chemical plants that recovery energy from different off-gases not listed in Annex X. Regarding the 4 LCPs that produce energy from waste combustion or co-combustion, we find that they take into account all the specific issues related to this kind of plants (i.e. detailed waste characterization, waste acceptance procedures, waste handling and storage, waste pretreatment and emissions to air), and adopt solutions that are best available techniques to prevent pollution. Moreover for one of these plants, the only one for which we have a significant set of monitoring data because it obtained the IPPC National Permit in 2008, we find that energy efficiency and air emissions of the principal pollutants are in

Impacts of Wind Power on Power System Stability

NARCIS (Netherlands)

Vittal, E.; Keane, A.; Slootweg, J.G.; Kling, W.L.; Ackermann, T.

2012-01-01

This chapter examines how wind power will impact the stability of power systems. It focuses on the three aspects of power system stability: voltage stability, rotor angle stability and frequency stability. It completes a detailed analysis as to how wind power in power systems will impact the

Long life gas laser system and method

International Nuclear Information System (INIS)

Hochuli, E.E.

1975-01-01

A long life gas discharge laser having an improved self-repairing cathode system is described. In a specific embodiment, water vapor having a partial pressure below about 10 -5 torr incorporated in a molecular sieve is used to provide impurities (in this case water vapor) for repairing the cathode surface by regenerating the oxide surface and/or preventing same from deteriorating. Other impurities may be incorporated in the molecular sieve such as hydrogen, oxygen, for example. In some cases CO 2 may be used. This application includes material disclosed in a paper entitled ''Continuation of the Investigation into Material Properties Affecting the Frequency Stability and Reliability of He-Ne Laser Structures'' submitted to the Office of Naval Research dated June 1972 by the inventor hereof and also a paper entitled ''Investigations of the Long Term Frequency Stability of Stable Laser Structures'' Progress Report for ONR Contract N00014-67-A-D239-0016 July 1972 by the inventor hereof. A royalty free license is hereby granted to the United States for use of the invention for all government purposes. (auth)

Structural Stability and Performance of Noble Metal-Free SnO2-Based Gas Sensors

Directory of Open Access Journals (Sweden)

Antonio Tricoli

2012-05-01

Full Text Available The structural stability of pure SnO2 nanoparticles and highly sensitive SnO2-SiO2 nanocomposites (0–15 SiO2 wt% has been investigated for conditions relevant to their utilization as chemoresistive gas sensors. Thermal stabilization by SiO2 co-synthesis has been investigated at up to 600 °C determining regimes of crystal size stability as a function of SiO2-content. For operation up to 400 °C, thermally stable crystal sizes of ca. 24 and 11 nm were identified for SnO2 nanoparticles and 1.4 wt% SnO2-SiO2 nanocomposites, respectively. The effect of crystal growth during operation (TO = 320 °C on the sensor response to ethanol has been reported, revealing possible long-term destabilization mechanisms. In particular, crystal growth and sintering-neck formation were discussed with respect to their potential to change the sensor response and calibration. Furthermore, the effect of SiO2 cosynthesis on the cross-sensitivity to humidity of these noble metal-free SnO2-based gas sensors was assessed.

Correlation between active layer thickness and ambient gas stability in IGZO thin-film transistors

International Nuclear Information System (INIS)

Gao, Xu; Mao, Bao-Hua; Wang, Sui-Dong; Lin, Meng-Fang; Shimizu, Maki; Mitoma, Nobuhiko; Kizu, Takio; Ou-Yang, Wei; Tsukagoshi, Kazuhito; Nabatame, Toshihide; Liu, Zhi

2017-01-01

Decreasing the active layer thickness has been recently reported as an alternative way to achieve fully depleted oxide thin-film transistors for the realization of low-voltage operations. However, the correlation between the active layer thickness and device resistivity to environmental changes is still unclear, which is important for the optimized design of oxide thin-film transistors. In this work, the ambient gas stability of IGZO thin-film transistors is found to be strongly correlated to the IGZO thickness. The TFT with the thinnest IGZO layer shows the highest intrinsic electron mobility in a vacuum, which is greatly reduced after exposure to O 2 /air. The device with a thick IGZO layer shows similar electron mobility in O 2 /air, whereas the mobility variation measured in the vacuum is absent. The thickness dependent ambient gas stability is attributed to a high-mobility region in the IGZO surface vicinity with less sputtering-induced damage, which will become electron depleted in O 2 /air due to the electron transfer to adsorbed gas molecules. The O 2 adsorption and deduced IGZO surface band bending is demonstrated by the ambient-pressure x-ray photoemission spectroscopy results. (paper)

Investigation of the role of gas hydrates in continental slope stability west of Fiordland, New Zealand

OpenAIRE

Crutchley, Gareth; Gorman, Andrew R.; Fohrmann, Miko

2007-01-01

Sediment weakening due to increased local pore fluid pressure is interpreted to be the cause of a submarine landslide that has been seismically imaged off the southwest coast of New Zealand. Data show a distinct and continuous bottom‐simulating reflection (BSR)—a seismic phenomena indicative of the presence of marine gas hydrate—below the continental shelf from water depths of c. 2400 m to c. 750 m, where it intersects the seafloor. Excess pore fluid pressure (EPP) generated in a free gas zon...

FY 1998 annual report on the preliminary research and development of techniques for developing resources from gas-hydrate. Studies on gas-hydrate exploration, excavation techniques, methods for assessing environmental impacts, and gas hydrate handling systems; 1998 nendo gas hydrate shigenka gijutsu sendoken kaihatsu seika hokokusho. Tansanado ni kansuru kenkyu kaihatsu, kussaku gijutsu nado ni kansuru kenkyu kaihatsu, kankyo eikyo hyokaho no kenkyu kaihatsu, riyo system ni kansuru chosa kenkyu

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

This R and D project is for the preliminary studies on development of the following 4 types of techniques for developing resources from gas-hydrates (GH): (1) gas-hydrate exploration, (2) excavation techniques, (3) methods for assessing environmental impacts, and (4) gas hydrate handling systems. The FY 1988 R and D results are described. For gas-hydrate exploration, the methods for analyzing inorganic ions and trace quantities of elements, which are necessary for accurately estimating the offshore GH around Japan, are established; and case studies are conducted for methods of predicting GH deposit forming mechanisms, and stability fields of GH, based on terrestrial heat flow and seismic data. For excavation techniques, GH decomposition rate is analyzed using a laboratory system which reproduces conditions of excavation of GH layers. For methods for assessing environmental impacts, a geo-hazard predicting model is established, to study ground displacement and gas leakage sensing systems and data transmission systems to cope with the hazards. For gas hydrate handling systems, an overall system is studied, and storage and transportation systems are outlined. (NEDO)

Experimental Study of Turbine Fuel Thermal Stability in an Aircraft Fuel System Simulator