天然气长输管道压气站通常采用离心式压缩机进行增压。由于增压后天然气温度较高,为防止进入管道的天然气温度过高,影响管道输气效率及防腐层使用寿命,通常需要设置空冷器以降低管道内工艺气输送温度。但在一些特殊工况下,增压后的天然气部分或全部未得到及时冷却,且在站内反复循环增压,以至天然气温度持续上升。通过ASPEN HYSYS软件进行模拟,以离心式压缩机启机工况作为典型循环温升工况进行分析,提出若在出站压力较高的情况下启动压缩机,应尽快将转速提升至出站压力对应转速,使系统进入正常输送状态,避免回流温升效应,从而保护压气站管道系统,保证压气站的安全运行。

Centrifugal compressors are commonly used in natural gas compressor stations for long-distance pipeline. As discharge temperature of natural gas after compressor will rise obviously, in order to prevent high temperature gas entering the pipeline which may affect the transportation efficiency and the anticorrosion layer service life, air cooler is usually provided to cool down the gas after compressor. However, in some special cases, part or all of the compressed natural gas may not bu cooled down in time, and gas is repeatedly compressed in the station, so that the gas temperature continues to rise circularly. Centrifugal compressor start-up case is analyzed as a typical circular temperature rise case. By simulating and analyzing the case with ASPEN HYSYS software, it suggests that if back pressure downstream compressor is high during compressor start up, compressor speed should be increased soon to protect the piping system and keep the safe operation for compressor station.