加氢裂化装置长周期运行的影响因素分析

Analysis of Factors Affecting Long-cycle Operation of Hydrocracking Units

以中国石油长庆石化公司120×104t/a加氢裂化装置为例,对影响加氢裂化装置长周期运行的关键因素——原料氮硫含量、原料干点、氢分压、氢油比、反应温度、空速、循环氢中NH3含量等进行分析,提出了保证加氢裂化装置长周期安全、稳定运行的建议:严格监控上游常减压装置蜡油拨出率和操作稳定性,控制原料的馏程和干点;密切关注原料氮含量、硫含量、残炭及重金属含量等指标,特别是当氮含量偏高时,要注意调整精制器反应温度;由于未转化油与新鲜料混合作为反应总进料,因此应尽量稳定分馏操作,保证未转化油指标及进量的稳定;控制反应系统升温速率,保证升温速率不能太快;适当提高氢分压与氢油比;要密切关注反应系统中NH3的含量,特别是原料中氮含量升高时,应采取措施使其保持在尽量低的水平上。

Taking PetroChina Changqing Petrochemical Company＇s 120×104t/a hydrocracking unit for example,this article analyzes the key factors affecting the long-cycle operation of hydrocracking units,including the contents of nitrogen and sulfur in feedstock,the dry point of feedstock,hydrogen partial pressure,hydrogen/oil ratio,reaction temperature,airspeed and the content of NH3 in circulating hydrogen.The article also proposes some suggestions to ensure a safe,long-cycle and stable operation of hydrocracking units.These suggestions include：strictly monitoring the extraction rate of wax oil and operational stability of the upstream atmospheric and vacuum distillation unit and controlling the distillation range and dry point of feedstock ;closely monitoring the contents of nitrogen,sulfur,residual carbon and heavy metals in feedstock,and particularly when the nitrogen content is on the high side,the reaction temperature should be adjusted for the refiner;as unconverted oil will be mixed with fresh feedstock to produce combined reaction charge,fractionation operations should be as stable as possible to ensure the stability of the indices of unconverted oil as well as the volume of feedstock fed;controlling the rate of temperature rise for the reaction system to ensure the rise of the temperature is not too fast;properly raising the hydrogen partial pressure and the hydrogen/oil ratio ;closely monitoring the content of NH3 in the reaction system and particularly when the content of nitrogen in the feedstock rises,measures should be taken to maintain the nitrogen content at the lowest possible level.