煤化工合成气低温分离工艺优化与分析

Optimization and analysis of low temperature separation process for syngas in coal chemical industry

关键词:  煤化工  低温分离  HYSYS模拟  BOX算法  火用效率 

Key words:  coal chemical industry  low temperature separation  HYSYS simulation  BOX algorithm  exergy efficiency

摘要:

目的 以新疆哈密某公司煤化工工艺过程为研究对象,解决煤化工合成气低温分离液化系统高能耗问题。方法 通过Aspen HYSYS软件模拟了单级混合制冷剂合成天然气分离液化流程,采用BOX算法,以系统最低能耗为目标函数,冷箱最小换热温差3 ℃为约束条件,优化了混合制冷剂组分配比及混合制冷剂循环一、二级压缩压力。结果 在保证LNG和制甲醇原料气产量不变的前提下,优化后冷箱冷热复合曲线更接近且平滑,换热效果更优,系统总能耗降低了16.59%,火用效率由37.96%提升至43.04%,显著提高了能源利用率。结论 BOX算法优化混合冷剂配比及压缩压力对降低合成气液化工艺能耗、提高系统火用效率有显著效果,对煤化工合成气低温分离液化工艺的研究具有借鉴意义。 

Abstract:

Objective Taking the coal chemical process of a company in Hami, Xinjiang as the research object, the problem of high energy consumption in the low temperature separation and liquefaction system of coal chemical syngas was solved. Methods Aspen HYSYS software was used to simulate the separation liquefaction process of the single mixed refrigerant synthetic natural gas. The distribution ratio of the component in mixed refrigerant and the first and second stage compression pressure of the mixed refrigerant cycle were optimized by using BOX algorithm, with the minimum specific power consumption of the system as the objective function and the minimum heat transfer temperature difference of the cold box as the constraint condition of 3 ℃. Results The results show that the cold-heat composite curve of the optimized cold box is closer and smoother and the heat exchange effects are optimized, while keeping the production of LNG and methanol raw gas unchanged, with overall power consumption of the system decreased by 16.59%, exergy efficiency increased from 37.96% to 43.04%, significantly increasing the energy utilization rate. Conclusion sThe optimization of mixed refrigerant ratio and compression pressure by BOX algorithm has a significant effect on reducing energy consumption of syngas liquefaction process and increasing exergy efficiency, which has reference significance for the research of low temperature separation and liquefaction process of syngas in coal chemical industry.