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- Kassman, Håkan, 1962, et al.
(författare)
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Ammonium Sulphate and Co-Combustion with Peat – Two Strategies to Reduce Gaseous KCl and Chlorine in Deposits during Biomass Combustion
- 2010
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Ingår i: In Proceedings from: "Impacts of Fuel Quality on Power Production & Environment", Lapland, Finland, August 29th - September 3rd 2010.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Combustion of a biomass with an enhanced content of chlorine (Cl) can result in operational problems including deposit formation and superheater corrosion. The strategies to reduce such problems include co-combustion and the use of additives. The positive effects of such measures are mainly due to sulphation of the alkali chlorides (KCl for biomass) to less corrosive alkali sulphates or capture of released alkali (K) in components such as potassium aluminium silicates. A mixture of wood pellets and straw pellets was fired in a 12 MW circulation fluidised bed (CFB) boiler. PVC was added to the fuel in order to achieve a further enhanced reference level of gaseous KCl during certain tests. Two strategies were applied to decrease the risk for superheater corrosion by reducing gaseous KCl and content of chlorine in deposits. The strategies were sulphation of KCl by injection of ammonium sulphate and co-combustion with peat. During co-combustion of biomass with peat both sulphation of KCl and capture of released K in ash components can be of importance. The results were evaluated by means of several advanced measurement tools including IACM (on-line measurements of gaseous KCl), deposit measurements (chemical composition in collected deposits, initial corrosion), ash analysis (chemical composition in fly ashes). The overall performance was better for ammonium sulphate, which significantly reduced gaseous KCl. Meanwhile almost no chlorine was found in the deposits. Only a minor reduction of gaseous KCl was obtained during co-combustion of biomass with peat although the chlorine content in the deposits was greatly reduced.
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| 2. |
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| 3. |
- Steenari, Britt-Marie, 1953, et al.
(författare)
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Agglomeration of the Bed Material in Fluidized Bed Reactors for Thermal Conversion of Biomass - A Threat for the Development of the Technology
- 2011
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Ingår i: Swedish - Finnish Flame Days January 26-27, 2011 in Piteå, Sweden, The Swedish and Finnish National Committees of the International Flame Research Foundation - IFRF and the Scandinavian - Nordic Section of the Combustion Institute.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Thermal conversion of biomass in fluidized bed systems for the production of heat and power and in the future also transportation fuels for vehicles through a gasification process need supply of biomass from various sources. These biomass fuels can vary a lot in quality and quantity. Many biomass types and waste derived fuels contain salts of alkali metals, i.e. potassium and sodium salts. When these alkali metals are released during combustion in fluidized bed systems using a bed material such as silica sand, agglomeration of the bed material may occur during unfavorable conditions. Thus, a significant amount of work has been put into the investigations of sintering mechanisms and the development of methods to prevent bed material sintering. In the present work combustion of alkali metal rich fuels alone and in combinations has been studied in the 12 MWth circulating fluidized bed (CFB) boiler located at the campus area of Chalmers University of Technology.
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| 4. |
- Zhao, Dongmei, 1963, et al.
(författare)
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Emissions of Mercury and Cadmium when Co-Firing Municipal Sewage Sludge and/or Waste Pellets with Biomass in a CFB Boiler
- 2012
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Ingår i: Proceedings of the 21st International Conference on Fluidized Bed Combustion.
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Konferensbidrag (refereegranskat)abstract
- Mercury (Hg) and cadmium (Cd) are the two most toxic heavy metals listed among trace elements. Emission limit values for these exist when burning waste in European Union (EU)countries. These emission limits are also valid for the case of co-combustion of waste fractions with a clean biomass as wood chips originating from stem wood. This has been studied in the 12MWth boiler located at Chalmers University of Technology by means of co-combustion of municipal sewage sludge and/or sorted, crushed and pre-dried waste pellets from IcoPower in the Netherlands. As base fuel a clean biomass was used consisting of only stem wood in the form of wood chips. Emissions of Hg and Cd were measured in the stack. An evaluation was also made of the importance of a highly efficient textile bag filter for the prevention of these emissions. Due to higher concentrations of Hg and Cd in the waste fuel streams, higher loading of Hg and Cd into the boiler was attained. The distribution of Hg and Cd into the outgoing flue-gas and fly ash streams was also determined.
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