小型混合制冷剂天然气液化流程设计与㶲分析

Design and exergy analysis of small scale mixed-refrigerant natural gas liquefaction process

分析了IFP-Axens公司开发的混合制冷剂循环Liquefin工艺关键技术,在此基础上设计了一种全新的小型混合制冷剂液化流程。比较了三个流程的主要流程参数,综合分析了换热器冷热负荷曲线和温差曲线。结果表明,压缩机和换热器的损失是循环的主要损失,可以通过选用效率更高的压缩机,或者改变压缩系统结构减少损;提高返流轻组分节流后压力可有效降低换热温差,通过进一步优化制冷剂组成和运行压力,可使换热温差更加均匀,减少换热器损,提高流程的经济性。

The thermodynamic analysis of the typical cycle was carried out and the exergy losses of the equipments were calculated. The key technology of Axens-Liquefin process was analysised. A new natural gas liquefaction process was put forward based on mixed refrigerants. The key parameters of the three different processes were compared,and the matching of the heating and cooling curves in main heat exchangers was also analyzed detailedly. The results indicated that,the exergy losses of compressors and heat exchangers were the main exergy losses of the process. Through choosing compressor with higher efficiency or changing the structure of compression system the exergy losses can be reduced. Increased the pressure of reflux flow of light components can reduce the temperature difference effectively. The components of refrigerant and the operating pressure was optimized in the new liquefaction process and the efficiency of the new process was improved.