改善重催在线胺液质量的研究

Study on Quality Improvement of Online Amine Solution in RFCC

重催胺液质量变差、再生贫胺液中H2S含量不合格会造成设备严重腐蚀,通过对胺液质量数据统计,分析再生塔底温度、储存时空气进入量、原料气带油、脱硫气体中SO2含量等对胺液质量的影响,发现装置在检修期间存在以下问题:胺液储存不当,空气中氧引起胺液降解造成检修后贫胺液中H2S和热稳态盐升高;重催胺液系统的贫胺液未安装过滤器;加氢裂化脱硫气和蒸馏脱硫低压瓦斯气进胺洗塔前没有分液罐;蒸馏低压瓦斯气中含有大量SO2。改善胺液质量的办法及建议:完善胺液系统设施,增设过滤器和分液罐;采用两个贫胺液沉降罐除去胺液中固体悬浮物;通过增加一条撇油线,或采用胺液在线净化技术定期脱除胺液中的烃类凝液;胺液储罐等设备采用充氮保护;循环泵和胺液泵入口维持正压,避免氧气进入胺液系统;定期抽检,分析胺液热稳态盐含量,监测降解产物和热稳态盐的积累情况,确保重油催化车间胺液再生系统操作稳定、贫液中H2S合格,降低胺液消耗、减少设备腐蚀。

In view of the heavy corrosion of equipment caused by poor amine solution quality and over-standard concentration of H2S in regenerated lean amine solution in RFCC,the influence of bottom temperature of regeneration tower,air intake during storage,feed gas with oil and SO2 concentration in desulfurized gas on the amine solution quality is analyzed based on the statistics of amine solution quality.The problems found during overhaul include the high H2S and heat stable salts(HSS) concentrations in lean amine solution after overhaul resulted by the amine solution degradation which is caused by oxygen under no nitrogen seal and unsuitable amine solution storage during overhaul,the feed gas with oil caused by the lack of filter in lean amine solution system and no separator set up for the desulfurized gas from hydrocracking unit and the desulfurized low pressure gas from distillation unit upstream of the amine washing tower,and a large number of SO2 contained in the low pressure gas from distillation unit.Feasible methods and suggestions on amine so-lution quality improvement are proposed including adding filter and separator to optimize the amine solution system,using two settling tanks for lean amine solution to remove the suspended solids from amine solution,adding an oil skimming pipeline or using online amine solution purification technology to regularly remove the hydrocarbon condensate from the amine solution,using nitrogen blanketing protection for amine storage tanks,maintaining positive pressure at the inlets of circulating pump and amine solution pump to prevent oxygen from entering the amine solution system,and regularly carrying out sampling for amine solution and HSS detection to monitor the accumulation of degradation product and HSS,so as to ensure the stable operation of amine solution regeneration system in RFCC unit and the qualified H2 S content of lean amine solution,minimize the consumption of amine solution and reduce equipment corrosion.