生物质焦促进煤粉燃烧动力学分析

Study on combustion kinetics of coal promoted by biomass char

采用热重分析仪系统研究了不同生物质焦配加量(0%、20%、40%、60%、80%、100%)对煤粉燃烧特性的影响,并分别采用非等温Flynn-Wall-Ozawa(FWO)和Kissinger-Akahira-Sunose(KAS)模型对燃烧过程活化能进行了计算。结果表明:煤粉中配加生物质焦有助于改善煤粉的燃烧特性,随生物质焦配加量的增加,煤粉的着火点和燃尽温度均降低,综合燃烧特性指数提高;生物质焦配加量为0%、20%、40%、60%、80%、100%时的活化能分别为164.24、146.57、136.90、119.91、95.79、62.37kJ/mol,活化能随生物质焦配加量的增加而降低。

Non-isothermal combustion experiments of different additive amounts of biomass char(0%,20%,40%,60%,80%,100%,mass fraction)were conducted by synthesized thermogravimetry analyzer(STA409 PC)from room temperature to 900 ℃ in air atmosphere.The changes of combustion characteristic parameters of pulverized coal in different conditions were analyzed.The results showed that,burning coal blended with biomass char was beneficial to enhancing the combustion characteristics.DTG curves of coal combustion moved to low temperature zones when the amount of biomass char increased.It indicated that both ignition and burnout temperature decreased,the burnout time shortened,the combustion characteristic index increased,and the combustion performance of blending coal were enhanced.The iso-conversional method involving Flynn-Wall-Ozawa(FWO)and Kissinger-Akahira-Sunose(KAS)model were adopted for the kinetic analysis of the main combustion process.The results indicated that,when the additive amount of biomass char varied from 0% to 100%,the activation energy decreased,which was 156.74kJ/mol,153.59kJ/mol,149.61kJ/mol,143.26kJ/mol,129.26kJ/mol,65.16kJ/mol,respectively.