不同热解工艺下半焦的微观结构特点及其对燃烧性能的影响

摘要：对比研究了3种直立内热炉半焦(熄焦方式分别为水泡熄焦、喷水熄焦及烟气干熄焦)及一种流化床热解半焦的微观结构及燃烧性能。通过对半焦组成、孔隙结构、有机官能团、碳化学结构及半焦微晶结构分析，获得了不同低温热解工艺半焦的组成及微观结构特点，明确了组成及微观结构与燃烧性能之间的关系。结果表明，不同热解工艺半焦的组成和微观结构差异明显，其对半焦的燃烧性能影响显著。干熄焦碳化学结构缺陷比例大，快速热解半焦孔隙结构发0达、挥发分高，与水喷焦相比水泡焦石墨化程度低；水喷焦燃烧性能优于水泡焦，干法所得半焦的燃烧性优于湿法；半焦的挥发分含量决定其燃点，在快升温速率条件下孔隙结构对半焦的燃烧性能影响较大，而慢升温速率条件下有序化度对半焦的燃烧性能影响较大。

Microstructure characteristics of semi coke under different pyrolysis processes and its influence on combustion performance

Microstructure and combustion performance of three kinds of semi coke from vertical internal heated pyrolysis furnace (water soaked quenching, water jetted quenching and dry quenching, respectively) and one kind of semi coke from fluidized bed fast pyrolysis were studied. Through analysis of composition, pore structure, organic functional groups, carbon chemical structure and microcrystalline structure of semi coke, the composition and microstructure of semi coke in different low temperature pyrolysis processes were obtained, and the relationship of composition to microstructure of semi coke and its combustion performance was clarified. The results show that the composition and microstructure of the semi coke in different pyrolysis processes are significantly different, which has a significant effect on the combustion performance of the semi coke. The dry dry quenched semi coke has a large proportion of chemical structure defects, the rapid pyrolysed semi coke has developed pore structure and high volatile content, the graphitization degree of the water jetted semi coke is lower than that of water soaked semi coke. The combustion performance of water jetted semi coke is better than that of water soaked semi coke, and combustion performance of semi coke obtained by dry method is better than that by wet method. The volatile content of the semi coke determines its ignition point. Under condition of rapid heating rate, the pore structure has a great influence on the combustion performance of the semi coke, while the degree of ordering under the slow heating rate has a great influence on the combustion performance of the semi coke.