LNG高压泵实际运行问题分析及建议

Analysis on actual operation problems of high pressure LNGpump and their suggested solutions

为解决高压泵液位大幅波动、泵井顶部引压管结冰严重及液位计测量严重不准等问题,结合某LNG接收站高压泵的实际运行数据对泵井内LNG物性、差压式液位计工作原理及安装形式等问题进行了详细分析。分析研究得出:LNG物性变化大是造成高压泵液位大幅波动的原因之一;差压式液位计上部引压点高于变送器的负压侧是造成泵井顶部引压管结冰严重的原因;正压侧引压管底部存在液柱是造成高压泵液位测量不准的主要原因。针对运行中的三种问题及主要原因,提出了严格控制再冷凝器运行参数、更改液位计安装方式、在高压泵正压侧引压管增加伴热带等改进和防范的具体措施,有效解决了高压泵实际运行过程中出现的相关问题,为LNG接收站高压泵的日常运行维护提供了新的解决思路。

In order to resolve the problems such as large fluctuation in high-pressure pump liquid level,frosting of pressure transducer tubing at the top of pump well and significant measurement inaccuracy of the liquid level gauge,this paper analyzes the physical properties of LNG in the pump well of the high-pressure pump in a LNG receiving terminal,and the working principles and installation method of the differential pressure level gauge.The research results show that:1)the big change in LNG physical properties is one of the reasons for the large fluctuation of high-pressure pump liquid level;2)the upper pressure detection point of differential pressure level gauge is located higher than the transmitter s negative pressure side,which is the main reason for pressure tubing frosting at the top of pump well;3)the liquid column formed at the bottom of the pressure tubing at the positive pressure side is the main reason for the inaccurate liquid level measurement of the high-pressure pump.In view of the three problems and their main causes,the following concrete measures are proposed:1)add a heat tracing element at the positive pressure side;2)change the installation method of the liquid level gauge;3)closely control the operation parameters of the recondenser.The research results can solve the above operation problems of high pressure pump,and provides a new solution to the routine operation and maintenance of high-pressure pump in LNG receiving terminal.