海上平台三甘醇脱水装置故障分析及工艺优化

Fault analysis and process optimization of TEG dehydration unit on offshore platform

目的解决某海上平台三甘醇脱水装置无法达到脱水要求的问题。方法基于现场实际生产数据,采用HYSYS软件进行该工艺系统的模拟分析,找出该系统运行问题的原因。结果脱水塔入口天然气中水含量过高是影响脱水系统效果的主要因素,改造方案应考虑入口过滤分离器和重沸器改造两方面。结合平台实际情况,最终确定改造方案为更换入口过滤分离器滤芯与重沸器电加热器。改造后,在表压5.2 MPa下的干气水露点从6℃降至-23℃,达到预期效果,且为后续扩容预留了操作空间。结论该海上平台三甘醇脱水装置处理量无法达到设计值的原因可能是入口过滤分离器性能不达标导致脱水塔入口天然气中水含量过高,建议在进行三甘醇脱水装置工艺设计时,严控入口过滤分离器处理指标,并根据入口过滤分离器处理指标配套三甘醇脱水装置。

Objective The aim is to solve the problem that a triethylene glycol(TEG)dehydration unit on an offshore platform could not meet the dehydration requirements.Methods Based on the actual production data,the simulation analysis of the process system was carried out by HYSYS software to found out the causes of the operation problems of the system.Results The high water content in the natural gas at the inlet of the dehydration tower is the main factor affecting the effect of the dehydration system.Both the inlet filter separator and the reboiler should be considered in the transformation plan.Combined with the actual situation of the platform,the transformation scheme was finally determined to replace the inlet filter separator filter element and the electric heater of reboiler.After the transformation,the dew point of dry gas water at gauge pressure of 5.2 MPa was reduced from 6℃to-23℃which achieved the expected effect and reserved the operation space for subsequent expansion.Conclusions The reason why the processing capacity of the TEG dehydration unit on the offshore platform cannot reach the design value might be that the performance of the inlet filter separator was not up to standard,which leads to the excessive water content of the natural gas at the inlet of the dehydration tower.It was suggested that the processing index of the inlet filter separator should be strictly controlled during the process design of the TEG dehydration unit,and the TEG dehydration device should be matched according to the treatment index of the inlet filter separator.