关键词: 生物质, 焦油, 热解, 白云石

Abstract: Main raw material is poplar sawdust. Catalytic cracking of tar is performed in a secondary fixed-bed cracking reactor using four types of dolomite as catalyst. Operation parameters like cracking temperature, catalyst type and residence time of reaction are investigated for their influences on tar cracking and gas quality. The characters of catalysts from different areas are measured in order to seek for suitable catalyst for commercial utilization in gasification systems. The results show that higher cracking temperature and longer residence time are favourable to tar cracking. When pyrolysis temperature goes beyond 1000℃, the tar cracking rate can reach 98.99%.Dolomites from different places show obvious difference in their catalysis effect. The dolomite from Shaanxi calcined at 900℃ can have tar cracking rate up to 95.14%. The most important factor that determines cracking effect of dolomites is their specific surface area after calcination. The bigger the specific surface area the better is catalysis effect. In order to obtain high catalysis effect, dolomite with bigger specific surface area should be chosen.

Key words: biomass, tar, pyrolysis, dolomite