天然气净化装置影响有机硫脱除的因素研究

Research on the factors affecting organic sulfur removal of natural gas purification unit

GB 17820-2018《天然气》规定,进入长输管网的天然气气质需满足H 2S质量浓度≤6 mg/m 3、CO 2摩尔分数≤3%、总硫质量浓度≤20 mg/m 3的要求。为达到GB 17820-2018的要求,中国石油西南油气田公司已有3个净化厂将原MDEA脱硫溶液升级为有机硫脱除溶剂CT8-24。与常规MDEA化学溶剂不同,有机硫脱除溶剂属于物理-化学溶剂,其对有机硫的脱除既有物理溶解也有化学吸收。因此,各工艺参数对有机硫脱除的影响更为复杂。分别在实验室及天然气净化厂对影响有机硫脱除的因素进行试验研究,包括吸收压力、气液比以及气液接触时间等,系统分析了各个因素变化对有机硫脱除率的影响。结果表明,较高的吸收压力、较低的气液比和较长的气液接触时间有利于有机硫的深度脱除,为现场装置的优化运行以及其他天然气净化厂的气质达标提供了技术参考。

The gas quality of natural gas entering the long-distance pipeline network shall meet the requirements of H 2S mass concentration no more than 6 mg/m 3,CO 2 molar fraction no more than 3%,and total sulfur mass concentration no more than 20 mg/m 3 in GB 17820-2018 Natural Gas.In order to meet the requirements of GB 17820-2018,the original MDEA desulfurization solution of three purification plants of PetroChina Southwest Oil and Gasfield Company has been upgraded to organic sulfur removal solvent CT8-24.The organic sulfur removal solvent is different from conventional MDEA chemical solvent.It belongs to physical-chemical solvent,which can remove organic sulfur both by physical dissolution and chemical absorption.Therefore,the influence of process parameters on organic sulfur removal is more complex.The factors affecting the removal of organic sulfur were studied in laboratory and purification plant respectively,including absorption pressure,gas-liquid ratio and gas-liquid contact time,etc.The effects of various factors on the removal rate of organic sulfur were systematically analyzed.The results showed that high absorption pressure,low gas-liquid ratio and long gas-liquid contact time were favorable to the deep removal of organic sulfur.It provides a technical reference for optimizing the unit operation and the gas quality of other natural gas purification plants up to standard.