海南小型LNG工厂液化工艺方案特点

Characteristics of the liquefaction process in small-scale Hainan LNG Plants

海南LNG工厂在国内首次利用氮气二级膨胀液化工艺。为此,讨论了海南LNG工厂天然气净化、液化系统技术方案的制订,针对原料气气质特点设计了DGA溶液脱酸工艺和氮气膨胀制冷工艺方案,对其进行了流程模拟计算,得到了各物流节点的设计参数,并计算出了天然气液化流程中压缩机能耗、制冷剂流量、各换热器的换热量等参数。装置运行考核结果表明:该DGA溶液脱酸工艺和氮气膨胀制冷工艺技术运用合理,工艺路线可行,工艺技术指标均达到了设计要求,为其他小型LNG工厂提供了一种新的天然气液化工艺选择方案。

The LNG Plants in Hainan primarily adopted the nitrogen two-expanders in series for the liquefaction process.Hereby,this paper discusses in detail how these plants lay out its schemes on the natural gas purification and liquefaction processes.Based on the properties of feedstock gas,the plants applied the deacidification by the diglycolamine (DGA) solution and the refrigeration by the nitrogen expansion.Through simulation of the above-mentioned processes,the design parameters of each logistics node were obtained,and those parameters in the liquefaction process were calculated out including the energy consumption of compressors,flow rate of refrigerant,and heat exchange amount of each heat exchanger.The smooth operation of the plants shows that the applied technologies help the LNG process to be economical and feasible,and the technical indexes meet the requirement of design.The successful experience in these plants will provide an alternative liquefaction process for other small-scale LNG plants in China.