热泵精馏在柴油加氢装置与干气提浓装置热联合上的应用分析

Analysis of heat pump distillation applied to heat combination between diesel hydrogenation unit and dry gas concentration unit

将热泵精馏技术推广应用于某炼厂柴油加氢装置和干气提浓装置之间的热联合,采用间接蒸汽压缩法,用热媒水作为中间介质,热媒水取走柴油加氢装置产品分馏塔塔顶气的余热,热媒水汽化并加压提温后,送至干气提浓装置,作为碳四吸收塔和碳四解吸塔再沸器的加热蒸汽。通过运行参数优化,将产品分馏塔塔顶气换热后的温度控制为130℃,蒸汽压缩后的压力为278.4kPa,压缩比为1.43。通过流程优化,创新性地采用双闪蒸罐的流程,避免使用水冷器冷却热媒水,可节省20t/h循环水,并回收0.2t/h蒸汽。采用热泵精馏系统实现两装置间的热联合,可回收柴油加氢装置分馏塔顶气热量6.93MW,节省干气提浓装置蒸汽11.5t/h,年总费用较原系统节省765.2万元,节能效益达50.66%;年总能耗节省4944.0吨标油,节能量达70.93%。

Heat pump distillation is applied to the heat combination between the diesel hydrogenation unit and dry gas concentration unit in a refinery.The medium-water is used to absorb the heat of the gaseous oil at the top of the product fractionator of the diesel hydrogenation unit.After the medium-water is vaporized and pressurized for temperature raising,it is sent to the C4 absorption tower reboiler and C4 desorption tower reboiler of the dry gas concentration unit,so as to save the steam.Through optimization,the temperature of the gaseous oil at the top of the fractionator after heat exchange is controlled to 130℃,the pressure of the steam after compression is 278.4kPa,and the compression ratio is 1.43.And the process of double flash tank is innovatively adopted to avoid using water cooler to cool medium-water,which can save 20t/h circulating water and recover 0.2t/h steam.The heat in the diesel hydrogenation unit was recovered by 6.93MW,and the steam was saved by 11.5t/h.The annual operation cost is saved by 7.652×106CNY compared with the original system,and the energy-saving benefit is 50.66%;the annual energy consumption is saved by 4944.0t EO, and the energy saving amount reaches 70.93%.