离心式BOG压缩机应用于大型LNG接收站的可行性分析

Feasibility analysis on the application of centrifugal BOG compressor at large LNG terminals

【目的】中国新建LNG接收站正朝着大型化方向发展,已建LNG接收站也已进入扩建期,接收站内BOG的生成量大幅增加且有相当一部分BOG来源稳定,为离心式BOG压缩机在大型LNG接收站的工程应用提供了契机。【方法】以中国某扩建LNG接收站为例,对该接收站内BOG的生成总量、BOG稳定生成量进行计算,从离心式压缩机与往复式压缩机的配置原则、离心式压缩机与往复式压缩机并联运行关键点、离心式压缩机的优势等多角度出发,系统研究了离心式BOG压缩机在中国LNG接收站推广应用的可行性。【结果】(1)新建或扩建接收站,LNG储罐能力在5座16×10^(4) m^(3)或4座22×10^(4) m^(3)以上的项目即可使用离心式压缩机;(2)由离心式压缩机覆盖接收站内BOG生成量的基本负荷,由往复式压缩机覆盖BOG生成量的峰值负荷,可以保证LNG接收站的正常运行;(3)离心式压缩机与往复式压缩机并联运行时,需要在往复式压缩机出口设置缓冲罐,以抑制往复式压缩机出口压力脉动对离心式压缩机产生的影响;(4)当两种型式的压缩机并联运行时,可以降低往复式压缩机出口排气压力的波动范围,以减少压力脉冲对下游BOG再冷凝器的影响。【结论】研究成果可为离心式压缩机在中国LNG接收站的推广应用、与往复式压缩机并联运行操作及工程设计提供理论指导和技术支撑。(图2,表5,参26)

[Objective]The development of new LNG terminals in China is currently oriented in the direction of large-scale construction while the existing LNG terminals are already undergoing expansion. Consequently, these terminals are generating an increasing volume of boil-off gas(BOG), with a substantial portion as stable sources, providing a promising opportunity for the application of centrifugal BOG compressors at these LNG terminals. [Methods]In this paper, an expanded LNG terminal in China was taken as the study subject.Its total generation and stable generation of BOG were calculated. A systematic study was performed to explore the feasibility of the widespread application of centrifugal BOG compressors at LNG terminals in China, from various perspectives, including the configuration principles of centrifugal compressors and reciprocating compressors, crucial factors in their parallel operation, and the advantages of centrifugal compressors. [Results](1) Centrifugal compressors are suitable for application at new or expanded terminals furnished with either five LNG tanks of 16×10^(4) m^(3) or four LNG tanks of 22×10^(4) m^(3).(2) Implementing a configuration that combines a centrifugal compressor to handle the base load of BOG generation and a reciprocating compressor to handle the peak load of BOG generation ensures steady operation at the terminals.(3) When centrifugal and reciprocating compressors are in parallel operation, it is crucial to incorporate a buffer tank at the outlet of the reciprocating compressor, in order to mitigate the impact of pressure pulsations at its outlet on the centrifugal compressor.(4) In the same parallel operation mode, it is recommended to reduce the fluctuation range of discharge pressure at the reciprocating compressor's outlet, to reduce the influence of pressure pulsation on the downstream BOG recondenser. [Conclusion]These research findings serve as theoretical guidance and technical support for the application promotion of centrifugal compressors at LNG stations in China, their parallel operation with reciprocating compressors, and relevant engineering design.(2 Figures, 5 Tables, 26 References)