含硫天然气脱硫工艺关键参数优化

Optimization of key parameters of sulfur-containing natural gas desulfurization process

为了提高含硫天然气的脱硫处理效率,以中国石油某天然气净化厂的原料气为研究对象,在分析了其组分及含量的基础上,采用Aspen HYSYS软件对MDEA法脱硫工艺的关键参数进行了优化,主要考察了吸收塔压力、贫胺溶液循环量、吸收塔塔板数、贫液温度、原料气温度以及再生塔回流比等参数对脱硫效果的影响。结果表明:吸收塔压力越高、贫胺溶液循环量越大、再生塔回流比越高,净化气中H2S的含量就越低;而贫液温度和原料气温度越高,净化气中H2S的含量就越高;随着吸收塔塔板数的逐渐增多,净化气中H2S含量则呈现出“先降低后升高”的趋势。由此得出适合目标天然气的最佳脱硫工艺参数为:吸收塔压力为3.5MPa,贫胺溶液循环量为105m^(3)·h^(-1),吸收塔塔板数为20块,贫液温度为40℃,原料气温度为20℃,再生塔回流比为0.8。在此工艺参数条件下净化气中H2S的含量低于6mg·m-3,能够满足GB 17820-2018中的一类气标准。

In order to improve the desulfurization efficiency of sulfur-containing natural gas,taking the feed gas of a natural gas purification plant of Petro-China as the research object,based on the analysis of its composition and content,Aspen HYSYS software was used to optimize the key parameters of MDEA desulfurization process,mainly investigating the pressure of absorption tower,circulation amount of lean amine solution,number of plates of absorption tower,temperature of lean solution,the influence of feed gas temperature and reflux ratio of regeneration tower on desulfurization effect.The results show that the higher the pressure of absorption tower,the greater the circulation amount of lean amine solution,and the higher the reflux ratio of regeneration tower,the lower the content of hydrogen sulfide in the purified gas;The higher the temperature of lean solution and feed gas,the higher the content of hydrogen sulfide in purified gas;With the gradual increase of the number of plates in the absorption tower,the hydrogen sulfide content in the purified gas shows a trend of"first decreasing and then increasing".The optimal desulfurization process parameters suitable for the target natural gas are obtained as follows:the pressure of absorption tower is 3.5MPa,the circulation volume of lean amine solution is 105m^(3)·h^(-1),the number of absorption tower plates is 20,the temperature of lean solution is 40℃,the temperature of feed gas is 20℃,and the reflux ratio of regeneration tower is 0.8.Under this process parameter,the content of hydrogen sulfide in the purified gas is lower than 6mg·m-3,which can meet the Class I gas standard in GB 17820-2018.