| 1. |
- Lyngfelt, Anders, 1955, et al.
(författare)
-
Dependence of Sulphur Capture Performance on Air Staging in a 12 MW Circulating Fluidised Bed Boiler
- 1993
-
Ingår i: Gas Cleaning at High Temperatures, Eds. R. Clift and J.P.K. Seville, Blackie Academic & Professional, Glasgow, ISBN 0 7514 0178 1.. - 0751401781 ; , s. 470-491
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Three cases of air staging were examined in a 12 MW circulating fluidised bed boiler: i) no staging, ii} normal staging and iii) intensified staging. The conditions inside the combustion chamber were investigated by zirconia cell measurements of the oxygen partial pressure, 0.35, 0.65 and 8 m above the bottom air distributor plate. A significant effect of the degree of staging was seen in the two lower locations: At 0.65 m height the fraction of time under substoichiometric conditions was low in the no-staging case (2-35%), at normal staging it was 70-90%, whereas at intensified staging it was 100Y.. At 0.35 m height, i.e. in the dense bed, a similar effect was seen, although the fraction of time under reducing conditions was lower. The fraction of time under reducing conditions was low in the top of the combustion chamber in all three cases . The increase in the fraction of time under reducing conditions with a higher degree of staging is associated with a decrease in sulphur capture. It is assumed that a release of SO2 from CaSO4 takes place during the transitions between oxidising and reducing conditions. Thus, the rapid alternations between oxidising and reducing conditions, as seen with the zirconia cell, offer an explanation of the reductive decomposition and, accordingly, of the dependence of sulphur capture on temperature and on the extent of staging.
|
|
| 2. |
- Thunman, Henrik, 1970, et al.
(författare)
-
A cost effective concept for generation of heat, electricity and transport fuel from biomass in fluidized bed boilers – using existing energy infrastructure
- 2007
-
Ingår i: Proceedings of the 15th European Biomass Conference & Exhibition - From research to market Deployment, Berlin, Germany, 7-11 May 2007. - 888940759X
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Poly-generation of various energy carriers from biomass is a cost effective option to initiate production of transport fuels from lignocellulosic biomass. Traditionally, the routs for this option have been trough greenfield gasification reactors. Here, on the other hand, the infrastructure of existing boilers is used for introduction of the gasification technology, which lowers cost and minimizes risks. The concept is based on adding a gasifier to existing fluidized bed boilers. An evaluation indicates the possibility of producing between 25 to 50 % of syngas, based on fuel input, without reducing the power output of the boiler. The process uses the thermal flywheel of the fluidized bed as a means to devolatilise the biomass. Only in Sweden there are around 100 fluidized bed boilers, which are potentially appropriate to be retrofitted with the proposed concept, whereof around 40 are large enough to give a low risk option for production of transport fuels within the present energy infrastructure. To demonstrate the concept, the Chalmers 12 MWth circulating fluidized bed boiler will be retrofitted according to this concept, resulting in co-generation of around 2 MWth product gas. The gas will be used temporarily for production of heat and electricity. The unit will, however, be prepared in such a way that the gas in a later stage can produce any Fischer-Tropsch fuel or synthetic natural gas. The retrofit is planed for the summer of 2007 and the plant is planned to be in operation in October 2007. This paper presents and discusses an evaluation of the concept.
|
|
