基于Aspen HYSYS方法沼气液化流程设计及分析

Biogas Liquefaction Process Design and Analysis Based on Aspen HYSYS

液化流程设计是小型沼气液化系统开发的关键技术问题。在深入研究天然气液化流程的基础上,文章设计了小型氮气膨胀、混合制冷剂液化两套典型液化流程,比较两者的关键参数及换热器中冷热流分布情况,以生产单位流量的生物质LNG(liquefied natural gas)为最小能耗为优化目标。结果表明:氮气膨胀流程中换热器冷热温差比较大,能量损失较大。混合制冷沼气液化流程中换热器中冷热曲线较为接近,最小温差为3.43℃,冷量损失较小,比功耗较低。因此混合制冷沼气液化流程较适合沼气液化。

Design of liquefaction process is a key technology for the development of small biogas liquefaction system. Two sets of typical liquefaction process,i. e. small nitrogen expansion and mixed refrigerant cycle,were designed for small biogas liquefaction system in this paper. Their key parameters,and the cold and heat flux distribution in the heat exchanger,were compared. The minimum energy consumption was used for the optimization object. The optimization results showed that the cold and hot temperature difference was relatively large in heat exchanger of nitrogen expansion liquefaction process,and so the energy loss is large; while the heat and cold curve was close for the mixed refrigerant cycle,in which the minimum temperature difference was 3. 43 ℃,loss of cooling capacity was small,and the power consumption was low.