天然气液化工艺技术比较分析

近期LNG工业快速增长再次刺激了LNG工艺的技术发展，使得一些传统的LNG生产工艺得到了关注，尤其是混凝土结构的、驳船型、浮式LNG装置等小规模LNG项目的应用。根据工作实践并查阅大量国内外资料，较系统地从LNG产量、功耗和生产线效率等方面对5种基本负荷型LNG工艺进行了比较分析，包括丙烷/混合制冷工艺、复迭式制冷工艺、双混合制冷工艺、单混合制冷工艺和带预冷的氮气膨胀工艺。其中，单混合制冷工艺流程、氮气膨胀制冷循环流程工艺简单，设备数量少，装置占地面积小；丙烷/混合制冷工艺流程、双复迭式制冷工艺流程、双重混合制冷工艺流程工艺较复杂，设备数量多，装置占地面积较大。在热带地区建造大型LNG装置采用丙烷/混合制冷工艺最好；氮气膨胀制冷循环流程因其工艺简单，设备数量少，制冷剂易获得和补充，较适合用于边远地区和海上小型天然气处理工厂。

LNG processing technologies and comparison analysis

In recent years, rapid development of LNG industry has accelerated the processes of LNG technology, which rouses attention even to some traditional LNG processes again, especially those applied to small scale projects such as concrete structure, barge type, and floating LNG installation. Through comparison analysis on five types of basic loading LNG processing technology including propane/MR process, cascade refrigeration process, double mix refrigeration (DMR), single mix refrigeration process, and pre cooling Nitrogen expansion process, this paper concludes that a. single mix refrigeration and Nitrogen expansion processes feature by simple process, few equipments and less land occupation, while the other three are much more complex with more equipments needed and more land occupied; b. for large scale LNG installation in tropical areas, the propane/MR process is the best choice, and for small scale installation in remote area or offshore area, Nitrogen expansion process is the best choice for its easily handled process, few equipments and accessible refrigerants. Based on author's working experience and a large amount of documents from home and abroad, each LNG processing technology has been systematically described and compared with each other through LNG production capacity, energy consumption and production efficiency.