对二甲苯装置热直供料改造效果分析

Analysis of the effect of direct heat-supply materials modification for paraxylene unit

某炼油厂Ⅲ连续重整装置热直供C_(8)芳烃给对二甲苯装置时,存在泵压头不足的问题,通过对原设计热直供流程改造,热直供料才得以实际应用。随着热直供料的增加,对二甲苯装置吸附进料中苯、甲苯、邻二甲苯含量升高,非芳含量下降;为维持吸附进料温度和异构化白土塔进料温度不变,脱庚烷塔进料温度下降。在Ⅲ连续重整装置C_(8)芳烃供料和C_(8)芳烃来源总量一定的情况下,随着热直供料的增加,邻二甲苯产量略微下降。由于优质甲苯塔塔底来料和吸附进料中邻二甲苯含量的增加,对二甲苯产量增加。在C_(8)芳烃热直供料流量为23 t/h、C_(8)芳烃冷供流量为13 t/h情况下,节约燃料气约96 m^(3)/h,降低了生产运行能耗,通过计算冷热C_(8)芳烃焓差很好地验证这个节能效果。

There is a problem of insufficient pump pressure head in the C_(8) aromatic direct heat-supply from the third continuous reforming device in an oil refinery on the paraxylene device.By transforming the original design of the direct heat-supply process,the direct heat supply process can be applied in practice.With the increase of direct heat-supply materials,the contents of benzene,toluene and oxylene in adsorption feed have been increasing and the non-aromatic content has been decreasing.In order to maintain the adsorption feed temperature and isomerized white clay tower feed temperature,the deheptane tower feed temperature is decreased.When the flow rate of C_(8) aromatics from third continuous reforming unit and the total source of C_(8) aromatics are constant,the output of o-xylene slightly decreases with the increase of direct heat-supply materials.The production of pxylene increased due to the increase of high quality feed from toluene tower bottom and the content of oxylene in adsorbed feed.When the direct heat-supply materials flow of C_(8) aromatics is 23 t/h and the cold feed flow of C_(8) aromatics is 13 t/h,the fuel gas is saved by 96 m3/h,which reduces the energy consumption in operation and verifies the energy conservation effect by calculating the enthalpy difference of C_(8) aromatics.