催化汽油脱臭过程多硫化物产生的原因及解决途径

Cause and Solving Approach of Polysulfide in the Deodorization Process of Catalytic Gasoline

在纤维膜接触器中,元素硫与汽油脱臭生成的二硫化物反应生成多硫化物,造成汽油的铜片腐蚀不合格。实验分析判断,多硫化物是引起催化汽油纤维膜接触器脱臭出现阶段性铜片不合格的原因。对其形成机理的研究和定性分析,证实上游汽油来料中元素硫是直接原因。催化裂化压缩富气及汽油中含有较高浓度的硫化氢,在有氧气存在的水洗环境下,当pH值小于8.0时,易产生元素硫并溶于汽油。用实验室分析结果指导生产工艺参数的调整,汽油铜片腐蚀问题得到了有效解决。分析了碱液置换对缓解汽油铜片腐蚀的机理。防止多硫化物产生、消除其对汽油铜片腐蚀的影响主要措施有:提高汽油水洗环境的pH值;减少压缩富气中氧气的夹带;碱液置换。

In fibrous membrane contactor, elemental sulfur reacted with disulfide from gasoline deodorization to form polysulfide, which resulted in disqualification of gasoline copper corrosion. Based on the experimental analysis, polysulfide was the reason of periodical copper corrosion disqualification in catalytic gasoline fibrous membrane contactor deodorization. The research on polysulfide formation mechanism and qualitative analysis confirmed that the direct cause of polysulfide formation was that upstream gasoline material contains elemental sulfur. More hydrogen sulfide existed in catalytic cracking compression unstripped gas and gasoline. In water washing environment containing oxygen, elemental sulfur was easy to produce and dissolved in gasoline when pH was less than 8.0. Adjusting process parameter with laboratory analysis result, gasoline copper corrosion problem was resolved efficiently. The mechanism of gasoline copper corrosion lessened by alkali liquor replacement was analyzed. The main measures of prevention polysulfide produce and elimination its influences on gasoline copper corrosion were to increase pH value of gasoline water washing environmental, to decrease oxygenous carrying in compression unstripped gas and to carry out alkali liquor replacement.