煤热解-化学链气化耦合工艺流程模拟

Process simulation of coal pyrolysis coupled with chemical looping gasification

为实现煤的清洁高效利用,提出一种煤固体热载体热解-化学链气化耦合工艺。利用流程模拟软件Aspen Plus建立了该耦合系统的工艺流程模型,主要包括煤干燥单元,煤热解单元,空气反应器和燃料反应器。模拟结果表明:通过将煤热解单元产生的酚废水作为燃料反应器的气化剂,可有效减少载氧体循环量和废水排放量。在热解温度500℃、半焦气化温度800℃和载氧体氧化温度1000℃条件下,载氧体的循环比为1.32,焦油分析基收率为6.6%,耦合系统的能量利用效率为43.12%,其中煤干燥单元能耗和煤热解单元能耗分别占总能耗的32.68%和33.81%,是导致系统辅助能耗大的主要原因。当进料量(100kg/h)和工艺条件相同的情况下,与单独的煤热解和煤基化学链气化技术相比,该耦合工艺在热力学效率和对环境的友好方面都有一定优势。

In order to utilize coal in a clean and high-efficiency way,a coupling process integrating coal pyrolysis with solid heat carrier and chemical looping gasification(CLG)was proposed.The process was simulated by Aspen Plus and the models including coal pyrolysis,coal drying,air reactor(AR)and fuel reactor(FR).The results indicate that by using the phenol water produced in pyrolysis process as the gasification agent in the FR,phenol wastewater and the recirculating ratio of oxygen carrier were greatly reduced.Under the conditions of pyrolysis temperature of 500℃,gasification temperature of 800℃and oxidation temperature of 1 000℃,the simulation results show that the recirculating ratio of oxygen carrier is 1.32 and tar yield is about 6.6%analysis base,and the overall energy efficiency of the coupled system can achieve values of 43.12%.The energy consumptions in the drying and pyrolysis units account for 32.68%and 33.81%respectively,causing the highest energy destruction.With the same coal input(100 kg/h),the coupled system shows a better performance compared with its original individual processes in consideration of the thermodynamic efficiency and effects on the environment.