Premium
In Situ CO 2 Capture in a Dual Fluidized Bed Biomass Steam Gasifier – Bed Material and Fuel Variation
Author(s) -
Soukup G.,
Pfeifer C.,
Kreuzeder A.,
Hofbauer H.
Publication year - 2009
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.200800559
Subject(s) - tar (computing) , wood gas generator , fluidized bed , exothermic reaction , chemistry , chemical looping combustion , combustion , chemical engineering , syngas , fluidized bed combustion , waste management , biomass (ecology) , hydrogen production , hydrogen , materials science , coal , organic chemistry , oceanography , computer science , engineering , programming language , geology
The AER (absorption enhanced reforming) process, based on the dual fluidized bed steam gasification process, uses a bed material which, apart from its function as heat carrier, acts as a CO 2 transporting agent and selectively transfers CO 2 from the gasification reactor to the combustion reactor. Thus, a hydrogen‐rich gas is produced (H 2 55...70 vol.‐% db , CH 4 8...13 vol.‐% db , CO 5...11 vol.‐% db as well as CO 2 7...20 vol.‐% db ). Seven different CaO containing bed materials were tested for their principal applicability to the AER process with special focus on their influence on tar production. The amount of tars was generally found to be five times lower than with conventional gasification (at 850 °C) despite the low gasification temperatures (600–700 °C). Due to these low gasification temperatures, biomass with high alkali contents (e.g., straw), indicating a low ash melting point (< 800 °C), can be used under AER conditions. In summary, the AER process is very effective owing to the integration of the heat of the chemical reaction of CO 2 with CaO and the water‐gas shift reaction, which are both exothermic, into the gasification and the internal reforming of primary and secondary tars, which cuts off the formation of higher tars.