低温热在气体分馏装置上的应用

Application of Low-Temperature Heat in LPG Fractionation Plant

中国石化洛阳分公司气体分馏装置原设计规模为30×104t/a,采用五塔流程,2008年扩能改造后,加工能力达到65×104t/a,实际采用四塔流程,由脱丙烷塔(T501)、脱乙烷塔(T502)、丙烯塔(T503AB/CD)、脱异丁烷塔(T504)组成。装置设计能耗为56.53kg标油/t原料,2009年装置实际能耗为51.77kg标油/t原料,但与同期中国石化先进装置能耗(37.34kg标油/t原料)相比,在蒸汽和电的单耗上,尚有差距。对此,提出实施催化装置低温热与气体分馏装置深度热联合,以及气体分馏装置内部低温优化,可取消气体分馏装置能级高的蒸汽热源,用低温热替代蒸汽伴热,蒸汽作为装置备用热源,可以节约0.3MPa蒸汽10t/h,降低装置综合能耗0.9个单位。

Sinopec Luoyang Company′s LPG fractionation plant has a designed throughput of 30×104t/a and uses the five-tower distillation process.After a capacity expansion in 2008,the plant now has a throughput of 65×104t/a and virtually uses a four-tower distillation process,i.e.a depropanizer（T501）,a deethanizer（T502）,a propylene tower（T503AB/CD） and a deisobutanizer（T504）.The designed energy efficiency of the plant is 56.53kg of oil equivalent per ton of feedstock,and in 2009 the actual energy consumption was 51.77kg of oil equivalent per ton of feedstock.The plant′s energy efficiency is still lower than the advanced levels in Sinopec（37.34kg of oil equivalent per ton of feedstock）,particularly in terms of steam and electric power consumption）.This article proposes a series of methods to raise the energy efficiency for the plant,including introducing the low-temperature heat from catalytic units into LPG fractionation plants and optimizing the use of heat inside the LPG fractionation plant by cancelling the high energy-level heat source-steam-and replacing steam with low-temperature heat in tracing.The steam will be used a standby heat source for the plant.These measures could save 10 tons of 0.3MPa steam per hour and reduce the overall energy consumption of the plant by 0.9units.