烷基化装置再生酸浓度低的原因分析及对策

Reason analysis and countermeasures of low concentration ofregenerated acid in alkylation unit

某石油化工厂200 kt/a烷基化装置配套的20 kt/a废酸再生单元再生酸浓度低(设计值质量分数98%,实际只有96.6%),造成烷基化装置酸耗较大、新旧酸库存平衡难度大、设备管线腐蚀严重等问题。通过分析焚烧炉燃料干气氢含量、硫元素损失、静电除雾器去除水蒸气效果等影响因素,采取变更焚烧炉燃料为纯度99%以上的丙烷、调整废酸再生第一反应器铂金催化剂装填比例、增加液态硫磺燃烧系统、改造高温静电除雾器及优化单元操作等诸多方式,废酸再生装置产生新酸的酸质量分数提高至接近98%。减少了设备管道仪表等的腐蚀,降低了酸耗,并解决了新旧酸库存平衡难等问题,保证了烷基化装置安全平稳长周期运行。

A 20,000 TPY waste acid regeneration unit of a 200,000 TPY alkylation plant has some problems such as high acid consumption,difficult balance of new and old acid inventory,and serious corrosion due to the low concentration of regenerated acid(98%of the design mass fraction,only 96.6%of the actual value).By analyzing the influence factors such as hydrogen content of dry gas of incinerator fuel,sulfur element loss,and the effect of electrostatic precipitator to remove water vapor,many methods are adopted such as changing the incinerator fuel to propane with purity above 99%,adjusting the loading ratio of platinum catalyst in the first reactor of waste acid regeneration,increasing the liquid sulfur combustion system,reforming the high-temperature electrostatic precipitator,and optimizing the operation.The acid mass fraction of the new acid increased to nearly 98%.Then,the corrosion of equipment,pipelines and instruments is reduced,acid consumption is reduced,the inventory of old and new acid is balanced,thus ensuring safe,stable and long-term operation of the alkylation unit.