长庆石化连续重整装置低温热回收利用浅析

A Brief Study on Recovery of Low-temperature Heat in Changqing Petrochemical′s Continuous Reforming Unit

中国石油长庆石化公司60×104t/a连续重整装置预处理系统原设计流程为先加氢、再汽提、后分馏,这种工艺解决了预分馏塔顶拔头油的质量问题,减缓了设备腐蚀。但是运行过程中,由于预加氢原料性质变化较大,造成预加氢进料加热炉负荷较高,炉膛温度较高,给装置长周期运行带来隐患;同时,拔头油低温热不能合理回收利用,增加了装置电耗和水耗。通过对预处理工艺流程进行优化分析,在常压石脑油进预加氢混合进料换热器前新增一台预加氢进料油与石脑油分馏塔顶拔头油换热器,充分利用预处理石脑油分馏塔顶低温热源,提高预加氢进料温度,降低预加氢进料炉炉膛温度,确保进料加热炉安全平稳运行。分馏塔顶低温热源回收利用后,连续重整装置综合能耗下降了3.52kg标油/t,每年可产生经济效益约576万元。

The originally designed process of PetroChina Changqing Petrochemical Company＇s 60×10^4t/a con- tinuous reforming pre-treatment system is in the order of hydrogenation,stripping and then fractionation.Such process arrangement solved the quality issue with the overhead oil out of the pre-fractionating column and slowed down equipment corrosion.However,as the properties of pre-hydrogenation feedstock changed dramatical- ly,the pre-hydrogenation feedstock heating furnace worked at high loads and temperatures,which posed a threat to the unit＇s long-term stable operation.In addition,since the low-temperature heat of the overhead oil was unable to be recovered,the unit＇s power and water consumption was high.Based on an analysis of the pre-treatment process,a measure was taken to optimize the process.A heat exchanger was added for the overhead oil out of the pre-hydrogenation feedstock and naphtha fractionating column,before the atmospheric naphtha enters the heat exchanger for pre-hydrogenation feedstock mixture to make full use of the low-tem- perature heat at the top of the pre-treated naphtha fractionating column,to increase the temperature of the pre-hydrogenation feedstock,and to reduce the furnace box temperature of the pre-hydrogenation feedstock furnace ,thus ensuring a safe and stable operation of the feedstock heating furnace.As a result of the recovery of low-temperature heat from the top of the fractionating column,the overall energy consumption of the con- tinuous reforming unit dropped by 3.52kg of oil equivalent per ton of feedstock processed.Annual economic benefits from this measure amount to about 5.76 million yuan.