基于AspenPlus的过程系统层次结构化[火用]分析

Hierarchical exergy analysis for chemical processes based on Aspen Plus

针对复杂系统的热力学计算,提出基于Aspen Plus的系统火用损计算分析方法。针对大型复杂能源化工系统,按照层次分析的原则,将整个系统划分为系统、次级系统及单元设备3个层次,研究系统火用分析层次结构及相应的分析方法。提出权重因子和损失贡献比2个参数用于建立层次之间的关联,实现逐层计算。以天然气辅助煤多联供甲醇电多联产系统为例,进行系统用能状况的分析,得出系统用能的薄弱环节主要在于蒸汽轮机子模块和水煤浆气化模块,其次用损贡献比分别为36.2%和31.4%。

A hierarchical exergy analysis method is proposed in this work, which is used to evaluate the thermodynamic performance for a complex system. An energy and chemical process system can be divided into three levels by using system decomposition, including the entire system, subsystem and process unit. Their corresponding exergy analysis methods are put forward. The exergy loss contribution ratio and weighting factor are chosen to establish the linkage between the levels and to finish the calculation process level by level. Coal/natural gas co-feed and methanol/electricity co-production （COCO） system is illustrated as the case study. The COCO system is analyzed and evaluated using the proposed method. Results show that the steam turbine and coal water slurry gasification are the bottlenecks for the system exergy efficiency improvement; their corresponding exergy loss contribution ratios are 36.2 % and 31.4 %, respectively.