催化裂化汽油加氢脱硫装置换热流程对比

Comparison of heat exchange schemes for FCC gasoline hydrodesulfurization unit

基于催化裂化汽油两段选择性加氢脱硫工艺过程的特点,选取了两种典型的换热流程方案,从能耗、投资、设备数量以及操作稳定性等方面对其进行综合分析和比较。方案1将两段加氢作为一个整体考虑,采用梯度逐级换热,其换热效率高;方案2针对催化汽油加氢脱硫装置的特点,较方案1增设了分馏塔进料/塔底物料换热器。对比结果表明,方案1较之于方案2,能耗在初期、末期工况下分别低32.24和35.59 MJ/t,管壳式换热器数量少2台,节省投资30×104RMB$,但两段存在交叉换热,导致临氢管线较长,且蒸汽耗量和加热炉的操作负荷波动较大;方案2虽然能耗略高,但在应对初期、末期反应器所需温度差别较大的情况下,蒸汽耗量平稳,加热炉负荷波动小,操作稳定性更好。

Based upon the process features of two-stage selective hydrodesulfurization process for FCC gasoline,two typical schemes of heat exchange are selected,compared and analyzed in energy consumption,capital investment,equipment number and operating stability,etc.In scheme 1,the two stages of heat exchange are integrated and stepwise heat exchange is adopted so that the efficiency of heat exchange is higher.In scheme 2,main fractionator bottom feed/bottom heat exchanger is added based upon the characteristics of FCC gasoline hydrodesulfurization process.The comparison results show that the energy consumption of scheme 1 is 32.24 MJ/t and 35.59 MJ/t lower than scheme 2 in SOR and EOR,two heat exchangers are not required and saving of capital investment is 300,000 Yuan RMB.Whereas,the two-stage cross heat exchanger process requires longer pipelines containing hydrogen,and the steam consumption and the operation duty of fired heater fluctuate more greatly.Although the energy consumption of scheme 2 is a little bit higher than scheme 1,the steam requirement of scheme 2 is stable,there is little duty fluctuation in fired heater duty and the operation is stable in both SOR and EOR.