生物炭与木质素混合成型及其燃烧特性研究

Molding Fuel and Combustion Characteristics of Biochar and Lignin

以油茶壳热解炭粉和胶黏剂为原料,利用万能试验机进行生物质混合燃料成型试验。通过对比不同成型燃料抗压强度、松弛密度和比能耗,确定胶黏剂种类对燃料品质的影响。选取木质素作为胶黏剂考察了成型压力、温度、含水率、木质素添加量对成型燃料品质的影响,当优化成型工艺参数为成型压力6 k N、成型温度80~100℃、含水率20%、木质素添加量8%~9%时燃料品质最佳。对成型燃料进行热重试验,研究其燃烧过程及动力学特性。结果表明:燃烧主要分为4个阶段,着火温度为356.9℃,燃尽温度为553.3℃;燃料的挥发分燃烧是一级反应,固定碳燃烧是二级反应。

With the increasing depletion of fossil energy,people pay more and more attention to renewable energy.Biomass energy is considered to be the most potential energy,which is a research hotpoint for its cleanness,efficiency and safety.The development and utilization of biomass energy plays an important role in achieving sustainable development,improving the living environment and reducing carbon dioxide.Owing to the flourishing pore structure,biochar as a main product of biomass conversion has been widely used in the fields of adsorption separation,catalytic carrier and fuel and so on.The biochar prepared from Camellia oleifera shell pyrolysis and adhesive as raw materials was molded by using universal testing machine.By analyzing the compressive strength,relax density and specific energy consumption of molding fuel,the effects of different adhesives on physical quality of molding fuel were made sure.The influence of molding pressure,temperature,moisture content and lignin content was studied with lignin as molding fuel adhesive.The results showed that the fuel quality was the best at molding pressure of 6 k N,molding temperature of 80 - 100℃,moisture content of 20% and lignin content of 8% - 9%.Scanning electron microscopy（SEM） was used to study the microstructure of the fuel.The results showed that lignin can promote the formation of carbon powder particles,the structure of the fuel is complete and the surface is smooth.The combustion characteristics and kinetics of the fuel were studied by thermogravimetric analysis.The results showed that the combustion process included four periods：the dehydration stage of the raw material,the precipitation and combustion of volatile components,the combustion stage of the fixed carbon and the burnout stage,and the ignition temperature and burnout temperature was 356.9℃ and 553.3℃,respectively.The volatile combustion was a first order reaction,and the fixed carbon combustion was a two stage reaction.The significance of the research was to provide theoretical basis for the preparation of biomass carbon fuel which was easy to transport and storage.