单级混合冷剂天然气液化工艺热经济学分析与评价

Thermoeconomic analysis and evaluation of single-stage mixed-refrigerant natural gas liquefaction process

天然气液化工艺系统的投资高、能耗高,可通过热经济学分析来合理评价其工艺设备的技术经济性。依据某天然气液化工厂的实际工艺和运行数据,采用HYSYS模拟工艺流程。在经济分析、?分析基础上,构建各设备的热经济学成本平衡方程组及辅助方程组,分析各物流的热经济学成本。基于设备的燃料-产品定义和各物流的热经济学成本,以相对成本差、?经济系数来评价各设备的技术经济性,指出各设备的优化方向,并分析能量成本和非能量成本对产品单位热经济学成本的影响程度。结果表明:工艺系统中的压缩机3、冷剂泵2的?经济系数偏高,应考虑降低其投资费用或运行维护费用;能量成本是影响液化天然气生产成本的主要因素,其每增加10%,液化天然气的单位热经济学成本增加8.7%。研究成果可为天然气液化工艺系统的优化及运行维护提供指导和建议。

In terms of the great investment and high energy consumption of natural gas liquefaction process system,the technological economy of the process equipment can be evaluated reasonably through thermoeconomic analysis.The process flow was simulated with HYSYS based on the actual process and operation data of a natural gas liquefaction plant.Thereby,the thermoeconomic cost balance and auxiliary equations of each equipment were constructed based on economic and exergic analysis to analyze the thermoeconomic cost of streams.Besides,the technological economy of equipment was evaluated with the relative cost difference and the exergo-economic factor based on the fuel-product definition of the equipment and the thermoeconomic cost of each stream.Meanwhile,the optimization direction of each equipment was pointed out,and the influence degree of energy cost and non-energy cost on the unit thermoeconomic cost of the product was analyzed.The results show that the exergoeconomic factors of No.3 compressor and No.2 refrigerant pump in the process system are relatively high,and it is necessary to reduce their investment cost or the operation and maintenance cost.Additionally,energy cost is the main factor affecting the production cost of liquefied natural gas,and the unit thermoecomnomic cost of liquefied natural gas increases by 8.7%if the energy cost is increased by 10%.Generally,the research results could provide guidance and suggestions on the optimization,operation and maintenance of the natural gas liquefaction process system.