褐煤固体热载体热解-气化耦合工艺流程模拟

为实现褐煤的清洁高效利用,对褐煤固体热载体热解-气化耦合工艺进行了评价.利用流程模拟软件ASPENPLUS建立了该工艺的模拟流程,分析了处理规模为42t/h时褐煤干燥阶段和热解阶段的能耗、固体热载体与煤混合、分离、运输过程的机械能耗及燃烧半焦的比例.结果表明,该工艺可利用褐煤所含外在水分作为气化剂,节约了气化所需水耗,在水煤比为0.7的情况下,可节约水资源12.5t/h,褐煤热解可获得焦油产品2.6t/h,半焦24.3t/h,其中45%的半焦用于燃烧供热,55%用于气化;褐煤热解单元能耗占总能耗70%以上,是直接导致固体热载体用量大、燃烧半焦比例大以及系统辅助能耗大的主要原因.

Process simulation of solid heat carrier lignite pyrolysis coupled with gasification

In order to utilize lignite in a clean and high-efficiency way,a process of lignite pyrolysis by solid heat carrier coupling gasification is proposed.The process has been simulated by ASPEN PLUS.The handling capacity is 42 t/h;the energy consumption of lignite drying unit and pyrolysis unit is analyzed,as well as the proportion of char used to burn has been confirmed in simulation.The mechanical energy consumption is calculated,which refers to the processes of mixing,separating and transporting of solid heat carrier and lignite.The results indicate that the surface moisture in lignite can be utilized as gasification agent in the coupling process,which can save the water resource 12.5 t/h.Through pyrolyzing lignite,tar oil 2.6 t/h,char 24.3 t/h,can be obtained;and 45% char burns to supply energy for the system;the others char is gasified.The energy consumption of pyrolysis unit accounts for 70% of the whole energy consumption,which directly results in a large amount in solid heat carrier utilization and high ratio of char used to burn,and accordingly increases the mechanical energy consumption of auxiliary section.