溶剂脱沥青工艺优化

Optimization of Solvent Deasphalting Process

为整体优化溶剂脱沥青(SDA)工艺,降低成本和能耗,以管输减压渣油(VR)为原料,采用处理量3 kg/h溶剂脱沥青连续评价装置对核心抽提操作参数和抽提方式进行了考察和优化,并通过流程模拟考察了超临界溶剂回收条件、最小换热温差和溶剂/减压渣油质量比(剂/油质量比)对换热成本和综合能耗的影响。结果表明:在抽提压力4.5 MPa、剂/油质量比2.0~3.0、抽提温度100~140℃条件下,脱沥青油(DAO)收率为53.7%~75.4%;优选抽提温度120℃,剂/油质量比为2.5,抽提方式为预混-逆流-抽提。处理量为1×10^(6)t/a(操作时间8400 h/a)的SDA工业装置换热成本和综合能耗计算结果表明,优化超临界溶剂回收压力和温度并降低最小换热温差,可降低高压溶剂换热器热负荷6128 kW,综合能耗可降低143.63 MJ/t;剂/油质量比从2.8降至2.5,可降低高压溶剂换热器热负荷3463 kW,综合能耗可降低42.89 MJ/t。

To optimize the solvent deasphalting(SDA)process and reduce the cost and energy consumption,the core extraction operating conditions and extraction methods were optimized by the 3 kg/h solvent deasphalting continuous evaluation device when using pipeline vacuum residue(VR)as raw material.Moreover,the effects of supercritical solvent recovery conditions,minimum heat exchange temperature difference and solvent/residue mass ratio(solvent/VR mass ratio)on the heat exchange cost and energy consumption were investigated by process simulation.The results show that at the extraction pressure of 4.5 MPa,solvent/oil mass ratio of 2.0—3.0 and extraction temperature of 100—140℃,the yield of deasphalting oil(DAO)is 53.7%—75.4%;the optimized extraction temperature is 120℃,the solvent/VR mass ratio 2.5,and the extraction method is shown as a premixing countercurrent extraction process.The heat exchange cost and comprehensive energy consumption calculated for 1×10^(6)t/a SDA unit with an operation time of 8400 h/a reveal that through optimizing the recovery pressure and temperature of supercritical solvent and reducing the minimum heat exchange temperature difference,the heat load of high-pressure solvent heat exchanger can be reduced by 6128 kW and the comprehensive energy consumption is lowered by 143.63 MJ/t.When the solvent/VR mass ratio is reduced from 2.8 to 2.5,the heat load of high-pressure solvent heat exchanger can be reduced by 3463 kW,and the comprehensive energy consumption is lowered by 42.89 MJ/t.