Sample records for kuonaantumiskaeyttaeytymisen estaeminen prosessiolosuhteiden
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Energy Technology Data Exchange (ETDEWEB)
Moilanen, A; Laatikainen-Luntama, J; Nieminen, M; Kurkela, E; Korhonen, J [VTT Energy, Espoo (Finland)
1997-10-01
In fluidised-bed gasification, various types of deposits and agglomerates may be formed by biomass ash in the bed, in upper zones of the reactor, for instance in cyclones. These may decisively hamper the operation of the process. The aim of the project was to obtain data on the detrimental fouling behaviour of the ash of different types of biomass in fluidised-bed gasification, and on the basis of these data to determine the process conditions and ways of preventing this kind of behaviour. Different types of biomass fuel relevant to energy production such as straw, wood residue were be used as samples. The project consisted of laboratory studies and fluidised-bed reactor tests including ash behaviour studied both in the bed and freeboard. In laboratory tests, the sample material was characterised as a function of different process parameters. In fluid-bed reactors, the most harmful biomasses were tested using process variables such as temperature, bed material and the gasification agents. Bubbling fluidised-bed gasification tests with wheat straw showed that agglomerates with different sizes and structures formed in the bed depending on the temperature, the feed gas composition and bed material. Agglomerates consisted of molten ash which sintered with bed material and other solids. In all BFB tests, freeboard walls were slicked by ash agglomerates (different amounts) which, however, were easily removable. The results of this project and the earlier pilot-scale gasification experience obtained with the same feedstocks showed that useful characteristic data about ash behaviour can be obtained using laboratory tests and small scale reactors. (orig.)
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Preventing superheater corrosion by additives; Tulistimien kloorikorroosion estaeminen lisaeainein
Energy Technology Data Exchange (ETDEWEB)
Aho, M.; Vainikka, P. [VTT, Espoo (Finland); Skrifvars, B.J.; Yrjas, P. [Aabo Akademi, Process Chemistry, Turku (Finland)
2006-12-19
The new superheater protection methods enable combustion of demanding biomass with higher portions than at present. This benefit reduces CO{sub 2} emissions from energy production and the use of demanding biomass in energy production will extend replacing biowaste landfilling with strong CH{sub 4} formation. The results assist also to meet the goals of the use of logging residues in energy production in Finland. (orig.)
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Prevention of superheater corrosion caused by chlorine; Tulistimien kloorikorroosion estaeminen
Energy Technology Data Exchange (ETDEWEB)
Roppo, J. [Kvaerner Power Oy, Tampere (Finland)
2006-12-19
Combustion of CO{sub 2}-neutral fuels is becoming more attractive and common method to decrease CO2 emissions of energy production. Also well managed and controlled combustion of waste fractions compared to their landfilling produces much less greenhouse gas emissions. In combustion of these fuels in high efficiency power plants notably increased superheater corrosion risk is prevailing, mainly caused by chlorine. Typical such fuels are forest, agricultural and household residues, biological sludge's of pulp and paper industry and RDF made from separated municipal and industrial solid waste. The goal of the project is to develop clearly cheaper and more effective method to protect superheaters, which enables combustion of biomass and waste fuels with higher energy shares. Tests in pilot and full scale power plants will reveal the potential and applicability of the developed method for commercial use. (orig.)