耦合化学链氧解耦燃烧的煤分级利用系统过程模拟和分析

Process Simulation and Exergy Analysis for a New Coal Poly-generation System Integrating Pyrolysis and Chemical Looping With Oxygen Uncoupling

煤炭分级利用技术可有效提高煤炭利用率,但无法解决CO_2减排问题,而化学链氧解耦燃烧技术(chemical looping with oxygen uncoupling,CLOU)可有效处理半焦,实现CO_2捕集并减少有害物质NOx的生成。结合CLOU和煤分级利用技术,提出一种新型的煤炭高效利用系统,并通过Aspen Plus对该新型系统进行过程模拟和分析。结果表明,相比于常规煤分级利用系统,该系统的系统效率提高了2.12个百分点,效率提高了20.68%,系统损降低了22.04%,实现了能量的高效利用。耦合CLOU的煤分级利用系统的烟气中CO_2浓度高达96.21%,经冷凝可获取高纯度CO_2产品;NOx含量显著降低,能够有效的降低半焦燃烧过程中NOx的排放。耦合CLOU的煤分级利用系统将是一种具有发展前景的CO_2捕集和环境友好型的煤炭高效利用技术。

Although coal poly-generation technology can improve the coal utilization efficiency, it would still result in large amount of CO_2 emissions. The chemical looping with oxygen uncoupling（CLOU） technology exhibits high combustion efficiency with CO_2 capture. Therefore, a new clean coal utilization technology integrating coal pyrolysis and CLOU process was proposed, which can realize the multi-generation of gas, tar and heat/electricity with CO_2 capture. The coupled coal poly-generation system was modeled and compared with conventional coal poly-generation system by Aspen Plus in this paper. Through simulation and exergy analysis, it is found that the system efficiency increased about 2.12 percent points, the exergy efficiency increased by 20.68%, and the exergy loss is 22.04% lower when compared with that of the conventional coal poly-generation system. Moreover, high-purity（about 96.21%） CO_2 products can be obtained whilst NOx content was reduced significantly in the new system. The CO_2 poly-generation system integrated with CLOU would be a promising coal utilization technology with the properties of high efficiency, CO_2 capture, and environmental friendliness.