Abstract:

The utilization of low temperature heat and process optimization for aromatics complex were introduced. The tower top low temperature heat of the raffinate tower and the extraction tower was used to produce hot water, a small amount of the hot water was used to heat demineralized water from FCC unit, and most of the hot water was used to produce 0.35 MPa steam to solvent regeneration unit by the second type of heat pump technology. A small amount of the toluene tower top gas phase heat source was used to replace 3.50 MPa reboiled steam of the isomerization stripper, while the rest was used to produce 0.62 MPa low low pressure steam together with the low temperature heat of the heavy aromatics tower top. Most of the low low pressure steam was pressurized and used as the reboiled heat source for the aromatics extraction unit. The comprehensive utilization of low temperature heat between the aromatics complex and the external units was realized, and the heat exchange process of heavy aromatics tower and isomerization stripper bottom was optimized. After the implementation of the project, every year the aromatics complex saved 102.7 kt of standard coal, CO₂ emissions reduced by 256.1 kt, and energy consumption of p-xylene reduced by 3.22 GJ/t.

Key words: aromatics complex, low temperature heat utilization, process optimization, energy saving and emission reduction, heat sink, energy consumption, CO₂ emissions, PX

摘要：

介绍了芳烃联合装置低温热利用与流程优化情况。利用抽余液塔与抽出液塔塔顶低温热生产热水，少量热水用来加热催化裂化装置除盐水，大部分热水通过第二类热泵生产0.35 MPa蒸汽并送去溶剂再生装置；甲苯塔塔顶气相热源除了少量用来替代异构化汽提塔3.50 MPa再沸蒸汽外，其余部分与重芳烃塔塔顶低温热一起生产0.62 MPa低低压蒸汽，大部分低低压蒸汽增压后作为芳烃抽提装置的再沸热源。该方案实现了芳烃联合装置内部与外部装置低温热的综合利用，优化了重芳烃塔与异构化汽提塔塔底换热流程。项目实施后，芳烃联合装置每年节能102.7 ktce, CO₂排放量减少256.1 kt,装置对二甲苯能耗降低3.22 GJ/t。

关键词: 芳烃联合装置, 低温热利用, 流程优化, 节能减排, 热阱, 能耗, CO₂排放量, 对二甲苯