NATURAL GAS PRESSURIZED LIQUEFACTION PROCESS ADOPTING CASCADE REFRIGERATION AND CO2 REMOVAL BY ANTI-SUBLIMATION

摘要：

　　To reduce the area of offshore liquefied natural gas (LNG) plant,a novel natural gas pressurized liquefaction process combined with CO2 removal is put forward in this paper.Taking off CO2 pretreatment facility,the process uses a crystallizer to remove CO2 from natural gas by anti-sublimation during liquefaction process.The process adopts a cascade refrigeration cycle to obtain cooling energy and produce pressurized liquefied natural gas (PLNG),with dry ice as by-product.Because of higher liquefaction temperature in PLNG process,the three-stage cascade refrigeration cycle commonly used in conventional process is replaced by a CH4/C2H4 two-stage cycle in the proposed process.The natural gas with high CO2 content is firstly cooled at the pressure of about 1.5MPa,until the CO2 fraction is lowered to 0.5%.In this way,most of the CO2 in the feed gas is separated by anti-sublimation.To avoid further freeze-out in the following process,the remaining natural gas is compressed to a higher pressure,and then cooled down until it is liquefied.The performance of the process is simulated with HYSYS software.Taking unit product power consumption as the major index for analysis,the optimum parameters of the process are worked out in this paper.Besides,the effects of CO2 content on power consumption are also investigated,and the results indicate that higher CO2 content in feed gas leads to higher unit product power consumption.Moreover,the optimal values of unit product power consumption show that the novel process can liquefy natural gas at an acceptable energy cost,usually under 0.35 kWh/Nm3.Therefore,the novel process is a good option for offshore natural gas liquefaction.

关键词： liquefied natural gas carbon dioxide power consumption liquefaction process cascade refrigeration anti-sublimation

作者: Xiong X.J Lin W.S

作者单位: Institute of Refrigeration and Cryogenics,Shanghai Jiao Tong University,Shanghai 200240,China

会议类型: 国际会议

会议名称: 第六届亚洲制冷空调大会(ACRA 2012)

会议地点: 西安

会议语种:英文

页码: 1-8

在线出版日期: 2012-08-26（万方平台首次上网日期，不代表论文的发表时间）