加氢裂化装置预闪蒸罐研究

Research on Preflash Drum of Hydrocracking Unit

以某工业加氢裂化装置设计数据为基础,考察常压分馏塔进料加热炉前设置预闪蒸罐的必要性以及罐的温度、压力对分馏塔的影响,并对设罐后,闪蒸罐的操作条件对能耗、操作成本及投资方面的影响进行了对比。结果表明:对于以石脑油、航煤、柴油和尾油(作为产品送出装置或者作为循环油返回反应部分)为目标产品的加氢裂化装置,设罐可有效降低进料加热炉和分馏塔的负荷。在相同压力下,闪蒸罐的温度越高,分馏塔负荷越小;在相同温度下,闪蒸罐压力越低,分馏塔负荷越小。在分馏塔输入热量相同的情况下,罐的闪蒸温度高,可节省投资和能耗,闪蒸温度低,可节省操作成本。设计过程中可根据航煤和柴油分离要求的不同,在一定范围内灵活选择闪蒸罐的温度和压力。

Based on the design data of a hydrocracking unit, the necessity of setting a preflash drum in front of the fractionator feed heater was discussed as well as influence of operating temperature and pressure of the drum on the fractionator. The influence of operating conditions in the preflash drum on the energy consumption, operating cost and investment was analyzed. The results show that, for the hydrocracker units to produce naphtha, jet, diesel and UCO, loads of fractionator and relevant feed heater can be lowered to a large extent if preflash drum is installed. Under same pressure, the load of fractionator will be lowered with the increase of operating temperature in preflash drum; under same temperature, the load of fractionator will be lowered with the decrease of operating pressure in preflash drum; in the case of same heat input for fractionator, investment and energy will be lowered with the increase of flashing temperature in the drum, while operating cost will be lowered with the decrease of flashing temperature. The operating temperature and pressure can be optimized within some range during the process of engineering design based on different separation requirements of jet and diesel.