基于动态仿真的火炬气回收系统超压保护措施  

Overpressure protection measures for flare gas recovery system based on dynamic simulation

作　　者：马晨波 MA Chenbo(CNOOC Research Institute Ltd,Beijing 100028)

机构地区：[1]中海油研究总院有限责任公司,北京100028

出　　处：《中国海上油气》2024年第1期156-162,共7页China Offshore Oil and Gas

摘　　要：油气田火炬气回收是碳减排的重要手段,但目前针对火炬气回收系统(FGRS)尤其是超压保护方面还缺乏系统性研究。以文昌9-7海上钻井生产平台为例,采用K-Spice软件搭建了火炬气回收系统动态仿真模型,研究确定火炬气回收系统在不同放空工况下的超压保护措施。结果表明:火炬气回收系统分液罐的压力高高关断(PAHH)设定值应根据连续放空气量变化确定,参照现行规范设定的PAHH值(210 kPa)明显偏高,应调至38.5 kPa,以确保超压值不高于分液罐设计压力又满足平台低压设备的泄放背压要求;应急放空工况下,为确保一级保护和二级保护相互独立,火炬支路快速开关阀(ESD)的开阀时间应小于27 s;火炬支路ESD故障时,为确保应急放空过程中分液罐内压力不超过设计压力,同时考虑爆破膜泄压对上游设备泄放背压的影响,最终选择Z型爆破膜。目前该平台已结合上述关键参数形成了一套完整的火炬气回收方案,预期回收火炬气可达13万立方米/年以上,碳减排效果显著。本研究为火炬气回收系统超压保护措施关键参数确定提供了定量分析手段,为火炬气回收系统的设计提供了参考。Flare gas recovery system(FGRS)is an important method to reduce the carbon emission reduction for oil and gas fields,while it lacks the systematic researches,especially in overpressure protection point.Taking the WC9-7 DPP offshore platform as an example,a dynamic model was established by using the K-Spice software to determine overpressure protection measures under different relief cases.The results show that the setting value of pressure alarm high-high(PAHH)of the flare knockout tank should be determined according to the variation of recovered continuous flare gas flowrate.The PAHH value of 210 kPa in specification is too high,and it should be adjusted to 38.5 kPa,in order to guarantee the overpressure is not higher than the tank design pressure and also can meet the requirement the relief backpressure of low-pressure facilities on the platform.To ensure the independence of primary and secondary protection measures under emergency relief condition,the opening duration of emergency shutdown valve(ESD)on flare vent path should be less than 27 seconds.To ensure the tank pressure during the emergency relieving process does not exceed its design pressure and consider the impact of relieving by the pressure safety element(PSE)on the backpressure of upstream facilities,the Z-type PSE was finally selected.At present,a completed scheme for FGRS was made based on the key parameters stated above.A carbon emission reduction effect over 13000 cubic meters of flare gas per year can be anticipated.This study provides a quantitative analysis method to determine the key parameters of overpressure protection measures of FGRS and a reference for the design of FGRS.

关 键 词：碳减排 火炬气回收系统 超压保护措施 动态仿真 压力高高关断设定值 快速开关阀 开阀时间 爆破膜选型 

分 类 号：TE866[石油与天然气工程—油气储运工程]