分馏与吸收稳定系统的关联性分析及优化

由于原料性质不断"变重",影响了长庆石化公司1.4Mt/a重油催化裂化装置分馏与吸收稳定系统的平稳操作。对分馏与吸收稳定系统主要的关联性操作,即分馏塔顶的富气和粗汽油作为吸收塔进料的单向关联、分馏一中回流与稳定塔底温度的双向关联、轻柴油进再吸收塔与富吸收油返分馏塔的双向关联进行了分析,提出了优化措施建议:应适时调整补充吸收剂的量,使之与粗汽油的量之比保持在0.7～1.3的范围内;在减渣进料加工量为110t/h的工况下,将补充吸收剂流量控制在50t/h;稳定塔底重沸器取热量跟踪温度控制应尽快投用;将热量换算更换为流量换算;对一中和稳定塔底的换热流程进行优化;在处理量变化的情况下,应随着贫气量的变化,适时调节贫吸收剂的流量,保证再吸收塔的吸收效果;贫吸收油可改用分馏塔顶顶循油。

Correlation between Fractionation and Absorption-stabilization Systems of RFCC Unit and Optimization

The use of increasingly heavy feedstock has affected the stability of the fractionation and absorp tion-stabilization systems of PetroChina Changqing Petrochemical Company′ s 1.4Mt/a residue fluid catalytic cracking（RFCC） unit.This article analyzes the key correlated operations of the fractionation and absorption-stabilization systems of the unit,i.e.the unidirectional correlation between the enriched gas and crude naphtha at the top of the fractionation tower used as feed for the absorption tower,the bidirectional correlation between No.1 intermediate fractionation reflux and the temperature at the bottom of the stabilization tower and the bidirectional correlation between the entry of solar oil to the re-absorption tower and the return of rich absorption oil to the fractionation tower.The article also proposes some suggestions to optimize these operations ： timely adjust and replenish the amount of absorbent used to maintain the ratio of the amount of absorbent to that of crude naphtha within the range of 0.7-1.3;maintain the speed of replenishing absorbent at 50t/h when vacuum residue feed is processed at a rate of 110t/h;put the heat from the reboiler at the bottom of the stabilization tower into use as soon as possible in accordance with temperature control ;optimize the heat exchange process between the No.1 intermediate fractionation section and the bottom of the stabilization tower;timely adjust the flow of lean absorbent following the change in the amount of lean gas when the processing volume changes to ensure the absorption effect of the re-absorption tower ;the top-cycle oil at the top of the fractionation tower can be used as the lean absorbent oil.