FLNG液化冷剂压缩机和主制冷换热器关键技术的突破

为解决海上天然气长距离管输的问题(成本高和流动安全保障等),FLNG(floating liquefied natural gas)浮式液化天然气开发技术应运而生。目前,受国内相关行业发展水平的制约,FLNG液化核心设备均需进口,设备价格高、项目投资大。为此,基于目前FLNG主要的液化工艺,分析了国内外液化核心设备(冷剂压缩机、大型压缩机驱动器和大型液化换热器)的运用现状和关键技术——①开停车、火灾及变工况下的稳定运行技术;②FLNG晃荡工况对换热器性能和安全的影响;③采用改进后的制造技术和制造工艺,满足FLNG运用的需求;④外部管道及接口补偿技术;⑤泄露监测技术,针对性地归纳了其实现国产化的技术需求和发展方向,提出了开发设想和建议:FLNG主要液化核心设备国产化要充分依托国内企业,在设计技术、材料、制造技术上充分借鉴国外技术发展思路,加大企业与项目的联系程度,充分整合资源突破关键技术,加大试验平台建设和试验验证,实现样机突破和中试运用,为最终的工程运用和降低项目投资打下基础。

Key FLNG liquefaction technologies for refrigerant compressors and main cryogenic heat exchangers

For the purpose of solving the problems in long-distance offshore pipeline transmission (e.g. high cost and flow assurance), floating liquefied natural gas (FLNG) technology was developed. Due to limited technical levels in China, however, the key FLNG liquefaction equipments have to be imported, so the equipments are expensive and the project investment is high. In this paper, analysis was performed on domestic core liquefaction equipments (including refrigerant compressor, large-scale compressor driver and main cryogenic heat exchanger) in terms of their application status and key technologies based on current FLNG liquefaction technologies. The key technologies include stable operation technologies for startup, shutdown, fire and variable working conditions, the effect of FLNG sloshing on the performance and safety of heat exchangers, the improved manufacturing technologies and process which should conform to the FLNG application, compensation technologies of outer pipes and interfaces, and leakage monitoring technologies. Then, the technical requirements and development directions of localization were summarized, and development ideas and suggestions were proposed. The localization of core FLNG liquefaction equipments should be sufficiently dependent on domestic enterprises, referring to foreign technical ideas in terms of design, materials and manufacturing. It is necessary to strengthen the communication between enterprises and projects, integrate resources sufficiently to realize technical breakthrough, and increase experimental platform construction and experimental verification so as to realize prototype breakthrough and pass the tests for field application. This technology provides the basis for the ultimate engineering application and project investment reduction.