芳烃联合装置蒸汽热泵回收低温热方案对比

Comparison of low-temperature heat recovery schemes of steam heat pump in aromatics complex units

综述了芳烃联合装置低温热利用技术,包括直接利用即与装置内工艺物料换热,以及采用热载体换热后外送、发电、热泵回收等间接利用的方案。结合甲、乙两个芳烃联合装置各自的背景特点,采用发生低品位蒸汽以回收蒸馏塔顶冷凝热,并使用蒸汽热泵将低品位蒸汽压缩至目标压力的方案,匹配了装置内、外的蒸汽需求,使得装置低温热得到高效回收。甲、乙装置的能耗分别降低了108.0,89.6 kgEo/t对二甲苯。该方案由于使用蒸汽作为主要工质和产物,对各石化企业芳烃联合装置均具有较好的适用性。

The low-temperature heat recovery technology for aromatics complex unit is reviewed, including direct recovery(heat exchange with process materials in the unit) and indirect recovery(delivered to outside, generate electricity or heat pump after heat exchange with heat carrier). Considering the characteristics of aromatics complex units A and B, the scheme of generating low-grade steam to recover the condensation heat at the top of distillation tower and using steam heat pump to compress low-grade steam to the target pressure is adopted, matching the steam demand inside and outside the units, so that the low-temperature heat of the units can be significantly and efficiently recovered. The energy consumption of unit A and unit B is reduced by 108.0 and 89.6 kgEo/t p-xylene respectively. The plan chose steam as working medium and main product, having good applicability in aromatics complex units of various petrochemical enterprises.