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- Blasiak, Wlodzimierz, et al.
(författare)
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Reforming Of Biomass Wastes Into Fuel Gas With High Temperature Air And Steam
- 2005
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The presented work aims to provide information on solid biomass conversion into fuel gas as a result of air and steam gasification process. In contrary to the conventional gasification in this work highly preheated air and steam is used as a gasifying agent. Preheat of air and steam is realised by means of the high-cycle regenerative air/steam preheater. Use of highly preheated gasifying media provides additional energy into the gasification process that enhances the thermal decomposition of the gasified solids. The objective of this work is to provide information on the process of biomass wastes reforming to fuel gas using high temperature air and steam gasification.High Temperature Air/Steam Gasification of biomass wastes has very clear economical and environmental benefits. It will increase consumption of biomass thus decreases CO2 emissions. Apart from CO2 reduction possibility, the new process, High Temperature Gasification has the following advantages:- Clean fuel gas for production of heat or electricity,- No need to treat ashes from gasification since there is no ash or at least no carbon in the ash produced,- No need to landfill since the produced slag can be used for example as a building material.In this work high temperature air and steam gasification of charcoal and wood pellets in a fixed bed updraft gasifier is tested. The following conclusions were found out:• For both charcoal and wood pellets gasification cases it was seen that an increase of steam molar fraction in the feed gas decreases the temperature of the gasification, the gasification rate, the mass yield of the fuel and molar fraction of carbon monoxide but increases molar fraction of hydrogen,• An increase of the feed gas temperature reduces production of tars, soot and char residue as well as increases calorific value of the fuel gas produced,• Preheating of the feed gas obtains a higher gasification efficiency and a higher gasification rate,• High temperature air and mixture of air and steam used as feed gas in a fixed bed gasifier shows the capability of this technology of maximising the gaseous product yield,• High lower heating value of fuel gas and high molar fraction of hydrogen and hydrocarbons obtained by using high temperature air and steam gasification technology increase the technical possibility of the application of fuel gas produced.
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| 4. |
- Lucas, Carlos, et al.
(författare)
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Mathematical model of biomass gasification using high temperature air in fixed beds
- 2007
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Ingår i: Progress in Computational Fluid Dynamics, An International Journal. - 1468-4349 .- 1741-5233. ; 7:1, s. 58-67
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Tidskriftsartikel (refereegranskat)abstract
- A mathematical model has been formulated for predicting the main chemical and physical processes taking place during the fixed-bed gasification of biomass fuels using high temperature air (up to 1000 degrees C). Predicted gas species concentrations profiles and their maximum values are in good agreement with measurements. The results also show that when the temperature of feed gas (air) is increased a higher gasification rate, higher molar fractions of fuel gases (CO, H-2 and CmHn) are obtained, thus resulting in a higher LHV. At a high flow rate of the feed gases, the peaks of the fuel gas concentrations are slightly increased, and the gasification rate is strongly increased. A smaller particle size of the biomass fuels leads to higher peak values of the fuel gas species molar fractions, and a more stable gasification zone for a relatively long period of time.
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| 5. |
- Ponzio, Anna, et al.
(författare)
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Development of a thermally homogeneous gasifier system using high-temperature agents
- 2006
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Ingår i: Clean Air. - 1561-4417. ; 7:4, s. 363-379
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Tidskriftsartikel (refereegranskat)abstract
- An advanced twin component gasification system, named Thermally Homogenous Gasification (THG), is developed. Development, testing and numerical simulations of the THG have shown that increased temperature of the gasification agent, results in a higher gasification rate, higher ignition front rate, higher molar fraction of combustible species in the product gas (CO, H2 and CmHn), and consequently a higher LHV. Moreover, there exists a critical gasification agent temperature above which preheating is no longer efficient if the purpose is to maximise the yield of gaseous products.
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| 6. |
- Yang, Weihong, et al.
(författare)
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Performance analysis of a fixed-bed biomass gasifier using high-temperature air
- 2006
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Ingår i: Fuel processing technology. - : Elsevier BV. - 0378-3820 .- 1873-7188. ; 87:3, s. 235-245
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Tidskriftsartikel (refereegranskat)abstract
- Gasification of biomass using high-temperature agents (air/steam) has been proven to have many features superior to those of conventional gasification using low-temperature agents. In this work, an experimental fixed-bed gasifier is utilized to investigate the gasification of biomass using high-temperature air up to 1473 K. A mathematical model has been formulated for the prediction of the main chemical and physical processes and is used to study the influence of temperature, oxygen concentration and flow rate of the feed gas. Predicted gas species concentration profiles and their maximum values are in reasonable agreements with the measurements. The results show that: (a) When the temperature of feed gas is increased, a higher gasification rate, a higher ignition front rate, and higher molar fractions of fuel gases (CO, H-2 and CmHn), thus a higher LHV are obtained. (b) Increased oxygen concentration leads to higher peak values of the fuel gas concentrations, a higher gasification rate, and a larger ignition front rate.
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