Abstract:

Low-temperature heat utilization is an important energy-saving measure for refining enterprises. Analyzed the energy-saving potential of low-temperature heat in a certain aromatic hydrocarbon unit, and compared the low-temperature thermal power generation scheme and the low-temperature steam generation scheme based on the principle of “temperature matching and step utilization” of low-temperature waste heat. The low-temperature steam generation scheme was chosen, and a screw compressor was used to compress and boost the steam for the recovery of low-temperature heat in the unit. The low-temperature heat source at the top of the heavy aromatics tower, toluene tower, and extraction tower was selected for the first stage of low-temperature heat recovery renovation work. The large screw compressor was applied to steam compression conditions, which is the first application in the petrochemical industry. After the implementation of the project, 1.0 MPa steam was saved by 103.5 t/h, the total energy consumption of the unit was reduced by 4,474.4 kgoe/h, the annual energy saving was 37,585 toe, the annual steam operating cost was reduced by 65.77 million yuan per year, and the comprehensive energy consumption of aromatics was reduced by 37.53 kgoe/t(calculated as P-Xylene), with a very significant energy-saving effect.

Key words: aromatics unit, low-temperature heat, power generation, steam generation, steam boost, steam superheating, screw compressor, energy consumption

摘要：

低温热利用是炼化企业的重要节能措施。分析了某芳烃装置低温热的节能潜力，根据低温余热“温度对口、梯级利用”的原则，对低温热发电方案和低温热产蒸汽方案进行了比较。选择了低温热产蒸汽方案，同时利用螺杆压缩机对蒸汽进行压缩升压，进行装置低温热的回收。选取重芳烃塔、甲苯塔和抽出液塔的塔顶低温热源进行低温热回收改造工作，将大型螺杆压缩机应用于蒸汽压缩工况，这是在石化行业内的首次应用。项目实施后，节省1.0 MPa蒸汽103.5 t/h,装置总能耗降低4 474.4 kgoe/h,每年节能37 585 toe,蒸汽运行成本降低6 577万元/a,芳烃综合能耗降低37.53 kgoe/t(以对二甲苯计),节能效果非常显著。

关键词: 芳烃装置, 低温热, 发电, 蒸汽发生, 蒸汽升压, 蒸汽过热, 螺杆压缩机, 能耗