生物质热解焦油燃烧试验系统设计与试验

Design and Experiment on Biomass Pyrolysis Tar Combustion System

摘要:

生物质热解焦油作为热解炭化或气化过程的副产物，难以去除且危害较大。通过对热解焦油的理化性质分析，发现其具有较高的热值，燃烧后可以为热解设备提供热源，实现能量的循环利用。针对热解焦油雾化效果差、直接燃烧不稳定等问题，设计了二次雾化喷嘴，并提出一种生物质热解焦油伴气燃烧的工艺；采用一定量的热解气作为助燃剂，为热解焦油燃烧提供稳定的火焰，设计了热解焦油燃烧试验系统。燃烧试验表明，该燃烧器的焦油燃烧量为20~55kg/h，达到设计要求。当雾化空气压力为0.6MPa、热解焦油压力为0.2~0.4MPa、热解气压力为0.3~0.5kPa时，燃烧器燃烧稳定，火焰明亮。通过烟气分析仪发现燃烧烟气中CO和NOx含量较高，表明在燃烧室中的一次燃烧并未达到理想的燃烧效果。

Abstract:

Biomass tar is produced as a by-product in the pyrolysis process of biomass, which is difficult to remove and harm to human health. The physical and chemical properties of pyrolysis tar were analyzed and it was fond that it had a high calorific value. After combustion, it can provide heat source for pyrolysis equipment and realize energy recycling. Aiming at the problems of poor atomization effect and unstable direct combustion of pyrolysis oil, a secondary atomizing nozzle was designed. And a mixed combustion process of biomass pyrolysis tar and pyrolysis gas was proposed. And a certain amount of pyrolysis gas was used as a combustion supporting agent to provide a stable flame for the combustion of the pyrolysis tar. And a test system for pyrolysis oil combustion was developed. The burning test of tar showed that the burning quantity of tar in the burner was 20~55kg/h, which met the design requirement. And when the atomizing air pressure was 0.6MPa, the pyrolysis oil pressure was 0.2~0.4MPa, the gas pressure was 0.3~0.5kPa, the burner was burned stably and the flame was bright. Through the analysis and test of the flue gas analyzer, it was fond that the content of CO and NOx in the combustion flue gas was high, which showed that the primary combustion in the combustor did not achieve the ideal combustion effect. Therefore, it was suggested that the next step was to improve the combustion chamber and reduce CO and NOx emissions by secondary air distribution combustion of the burned flue gas.