降低高压加氢裂化装置氢耗的措施探讨

在加氢裂化装置中,氢气是正常生产不可缺少的原料。加氢处理、加氢裂化反应均需消耗氢气;同时,氢气消耗还包括机械泄漏、溶解损失以及微量排放等。氢气成本约占加氢裂化装置加工成本的7%～13%。中国石化某加氢裂化装置采用石油化工科学研究院(RIPP)开发的RN-32/RHC-1催化剂,设计转化率为58.3%(以重石脑油计算),馏出物计算方法转化率为60.3%。在此条件下,无论大小尾油方案,设计化学氢耗均为2.25%。实际生产中,装置转化率在60%左右,与设计值基本相当,但氢耗较高,各加工方案氢耗均在2.7%～3.0%范围。从加氢裂化装置理论氢耗入手,分析氢耗与实际操作的关联性,结合降低氢耗试验,分析原油品种变化和转化率对氢耗的影响,提出降低氢耗的主要措施应为优化加氢裂化反应转化率。另外,优化装置原料、降低原料干点也是降低氢耗的有效手段之一。

A Discussion on Measures of Reducing Hydrogen Consumption for High-pressure Hydrogenation Units

Hydrogen is the essential feedstock for a hydrocracking unit.Both the hydrotreating and hydrocracking processes consume hydrogen.Hydrogen consumption also includes mechanical leaks,dissolution loss and trace amounts of emissions.Hydrogen cost represents about 7%-13% of the processing cost of a hydrocracking unit.A hydrocracking unit in Sinopec uses the RN-32/RHC-1 catalyst developed by RIPP ,the designed conversion rate of which is 58.3% （calculated based on use of heavy naphtha） and distillate-based conversion rate is 60.3%.Under these conditions ,the designed chemical hydrogen consumption is 2.25% in both large and small tail oil scenarios. In actual production,the unit＇s conversion rate stands at some 60% ,basically equivalent to the designed value. However,the unit＇s hydrogen consumption is on the high side with the hydrogen consumption in all of the available processing plans falling in the range of 2.7% to 3.0%.Starting with the theoretical hydrogen consumption of hydro- cracking units ,this article analyzes the correlation between hydrogen consumption and actual operation ,examines the effect of a change in crude types and conversion rate on hydrogen consumption based results of hydrogen consumption reduction experiments, and proposes that the main measure of reducing hydrogen consumption should be optimizing the conversion rate of hydrocracking reaction.Optimizing feedstock and reducing the dry point of feed- stock is also one of the effective approaches to reducing hydrogen consumption.