Two-stage gasification: fine characterisation of wood chips pyrolysis step in a continuous fixed bed reactor
Two-stage gasification is a proven technology for combined heat and power generation, particularly as it enables the production of a high quality, virtually tar-free gas. In this work, we focused on the pyrolysis step of the process and carried out a parametric study on the effect of temperature and bed height on the yields and quality of the char/gases/tars produced. We used the Continuous Fixed Bed reactor (CFiB) at CIRAD that replicates the pyrolysis zone separately from the rest of the process. At the reactor outlet, char, gases and oils were sampled and analyzed; this enabled mass balance calculations over the whole process and provided relevant information on evolution and composition of pyrolysis products. When the temperature varied from 350 to 600°C, char yield decreased from 40 to 25% wt. while gases yield increased from 9 to 38% wt. Regarding condensates, pyrolytic water remained constant while secondary tars (phenol) increased when increasing pyrolysis temperature. Moreover, a larger bed height seems to favor secondary reactions on pyrolysis condensates, leading to the formation of additional char and gases.
| Main Authors: | , , , , |
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| Format: | conference_item biblioteca |
| Language: | eng |
| Published: |
s.n.
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| Subjects: | K50 - Technologie des produits forestiers, P06 - Sources d'énergie renouvelable, bois, pyrolyse, gazéification, biomasse, http://aims.fao.org/aos/agrovoc/c_8421, http://aims.fao.org/aos/agrovoc/c_26874, http://aims.fao.org/aos/agrovoc/c_34000, http://aims.fao.org/aos/agrovoc/c_926, |
| Online Access: | http://agritrop.cirad.fr/560538/ http://agritrop.cirad.fr/560538/1/document_560538.pdf |
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| Summary: | Two-stage gasification is a proven technology for combined heat and power generation, particularly as it enables the production of a high quality, virtually tar-free gas. In this work, we focused on the pyrolysis step of the process and carried out a parametric study on the effect of temperature and bed height on the yields and quality of the char/gases/tars produced. We used the Continuous Fixed Bed reactor (CFiB) at CIRAD that replicates the pyrolysis zone separately from the rest of the process. At the reactor outlet, char, gases and oils were sampled and analyzed; this enabled mass balance calculations over the whole process and provided relevant information on evolution and composition of pyrolysis products. When the temperature varied from 350 to 600°C, char yield decreased from 40 to 25% wt. while gases yield increased from 9 to 38% wt. Regarding condensates, pyrolytic water remained constant while secondary tars (phenol) increased when increasing pyrolysis temperature. Moreover, a larger bed height seems to favor secondary reactions on pyrolysis condensates, leading to the formation of additional char and gases. |
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