针对南海某油气田陆上终端天然气液化项目中天然气的性质和规模，对前置脱轻烃低压液化工艺、前置脱轻烃高压液化工艺、后置脱轻烃低压液化工艺和后置脱轻烃高压液化工艺4种路线和技术进行了模拟计算和分析对比，包括能耗、设备投资和运行成本等，通过优化比较，最终确定了优先选择前置脱轻烃低压液化工艺流程技术。前置脱轻烃低压液化工艺具有流程、工艺控制、开工过程简单，操作稳定的特点，同时该工艺主要设备数量最少，建设投资最少，财务净现值和内部收益率也具有一定优势。

A coastal oil and gas field onshore terminal natural gas liquefaction project is taken as the research object.According to the properties and scale of natural gas,four kinds of process routes and technologies,including prepositive light hydrocarbon-removing low pressure natural gas liquefaction process,prepositive light hydrocarbon-removing high pressure natural gas liquefaction process,postpositive light hydrocarbon-removing low pressure natural gas liquefaction process and postpositive light hydrocarbon-removing high pressure natural gas liquefaction process,are simulated,analyzed and compared in the aspects of energy consumption,equipment investment and operation cost.Through optimization and comparison,prepositive light hydrocarbon-removing low pressure natural gas liquefaction process is determined as the optimal process technology,which has the advantages of simple process,simple process control,simple start-up process and stable operation.In addition,it needs the fewest number of main equipment and the smallest construction investment,and shows advantages in the financial net present value and internal rate of return.