Abstract: Biomass gasification in the presence of steam was carried out to produce bio-gas in a fluidized bed reactor. The installation was made up of a fluidized bed reactor and a fixed bed cracking reactor. The feedstock was sawdust and the cracking catalyst included calcined dolomite and nickel-based reforming catalyst. The results showed that H2/CO (H/C) mole ratio greatly increased with increasing gasification temperature and steam/biomass mass ratio，but did not change much with increasing catalytic cracking temperature. In addition，in the catalytic cracking reactor using different kinds of catalysts would lead to different H/C. Two sections of catalytic cracking were used，sectionⅠwith calcined dolomite，and section Ⅱwith nickel-based catalyst. The tar cracking rate reached 96.70%. Using two sections of catalytic cracking not only would increase the tar cracking rate，increase the yield of H2 and CO，purify the biogas，but also could prevent the nickel-based reforming catalyst deactivation and extend its service life.

摘要： 在常压流化床上进行了生物质在水蒸气条件下的实验研究。实验装置主体由常压流化床反应器和固定床催化裂解反应器组合而成。生物质原料为木屑，焦油裂解催化剂分别选用煅烧白云石和镍基重整催化剂。实验结果表明，H2/CO(H/C)的摩尔比随着气化温度、水蒸气质量/生物质质量（S/B）的升高迅速增加，但催化裂解温度变化对H/C的影响较小。另外，在催化裂解反应器中使用催化剂种类不同，H/C也不同。本文采用两段催化裂解，一段催化剂采用煅烧白云石，二段采用镍基催化剂，焦油裂解率达到96.70％。采用两段催化裂解，不但可以提高焦油的裂解率，增加了H2和CO收率，净化生物质裂解气，而且可以防止镍基重整催化剂失活，延长其使用寿命。