天然气脱酸气装置动态建模及分析

天然气脱酸气装置是天然气开发过程中重要的组成部分,由于脱酸气装置的来气量经常发生变动,致使装置运行偏离最优工况。本文基于川渝地区某高含硫天然气脱酸气装置,首次应用HYSYS Dynamic流程模拟软件,建立天然气脱酸气装置动态模型,研究脱酸气装置在原料气的进气量在80%～130%负荷变化时,整套装置的动态响应过程,确定了常规PID控制方案对吸收剂循环量控制滞后,造成装置在高负荷下,产品气质量达不到标准;针对动态分析发现的问题,本文提出了一种比例控制方案,依据原料气的处理量的变化比例调节吸收剂循环量,并根据进入再生塔的富吸收液流量比例调节再生塔重沸器的负荷。动态分析表明,在原料气负荷变动条件下,装置可以始终保持产品气质量在要求之内,再生塔负荷也可以根据处理量的变化而自动调节,在低负荷运行时,降低装置的能耗。此比例控制方案大大提高了装置的操作弹性。

Dynamic modeling and analysis for natural gas sweetening plant

The sweetening plant is an important part of natural gas development process.Operating conditions of plant often deviate from optimal condition,because feed gas to plant is often change.A dynamic model of sweetening plant has been developed by a process simulation software - HYSYS Dynamic based on a real sweetening plant in the Sichuan.Dynamic responses of plant has been studied when the loading of feed gas changes between 80%and 130%.The problem which the quality of product gas could not meet the requirement has been found under normal PID control scheme.A proportional control scheme was proposed for the problem,and operating parameters can be adjusted according to the change of the loading of feed gas.Dynamic analysis shows that quality of product gas could be kept in the requirement.The new control scheme can decrease the heat loading of stripper under low loading operation.The operation flexibility of sweetening plant is increase significantly.