连续重整高温凝结水余热回收经济效益显著

长庆石化连续重整装置存在1.0MPa、1.7MPa、2.3MPa、3.5MPa四种不同压力的蒸汽产生的凝结水,导致出装置凝结水温度较高(达到180℃)、流量较大(为42.6t/h),该凝结水汇至公司凝结水管网。高温蒸汽凝结水在流动过程中,产生二次闪蒸,形成气液混相流,当流速增加或改变流向时引起水击,影响管网安全运行和下游除油、除铁装置的平稳运行。为了消除连续重整装置高温凝结水存在的隐患,2012年4月,决定对长庆石化凝结水余热回收系统实施改造。改造工程分两个阶段进行:2012年5月15第一阶段,凝结水罐V410吊装配管施工完成,投用后管网水击现象有所好转,但未能彻底解决;2013年10月第二阶段装,装置大检修中新增一台换热器、两台凝结水泵,同年11月12日施工完成。改造后,出装置凝结水温度由180℃降至128℃,除氧水温度提高12℃,每小时多产蒸汽5.4t,每年创效439万元,实现了高温凝结水的回收再利用,降低了装置运行风险。

An Analysis of the Economic Benefits of Recovering Residual Heat in High-temperature Condensed Water from Continuous Catalytic Reformers

PetroChinaChangqing Petrochemical Company＇s continuous catalytic reforming unit produces condensed water from vapor of four different pressures--1.0MPa, 1.7MPa,2.3MPa and 3.5MPa.As a result,the tempera- ture of condensed water flowing out of the unit is very high （180℃） and volume is also high （42.6t/h）.The condensed water flows into the company＇s condensed water pipeline network.The high-temperature condensed water produces secondary flash distillation when it flows and produces a gas-liquid mixed-phase stream.A water attack will result when the flow rate increases or the direction of flow changes,in turn affecting the safe operation of the pipeline network and downstream deoiling and deironing units.In order to remove the trouble hidden in the high-temperature condensed water from the continuous catalytic reformer,PetroChinaChangqing Petrochemical Company decided to revamp its condensed water residual heat recovery system.The revamping was completed in two phases.Phase one began on May 15,2012,which saw the completion of construction of the condensed water tank V410.The phenomenon of water attack in the pipeline network improved after the condensed water tank was put into use but was not eliminated.In October 2013,phase two began and a heat exchanger and two condensed water pumps were added during a unit overhaul.Phase two was completed on November 12 of the same year.After the revamping,the temperature of the condensed water coming out of the continuous catalytic reformer dropped to 128℃ from 180℃,the temperature of deoxygenat- ed water increased by 12℃,steam production increased by 5.4t per hour and annual economic returns reached 4.39 million yuan.The revamping enables the recovery of high-temperature condensed water and helps reduce the risk of operation of the continuous catalytic reforming unit.