催化裂化汽油加氢脱硫装置能耗分析及优化方案

采用流程模拟技术,从装置负荷率、产品含硫量指标、装置能耗构成、主要用能点等方面,对催化裂化(FCC)汽油加氢脱硫装置的关键能耗因素进行定量分析,针对中国石油克拉玛依石化有限责任公司(简称克石化公司) 50万t/a FCC汽油加氢脱硫装置提出优化方案。结果表明:影响FCC汽油加氢脱硫装置能耗的主要因素为装置负荷率和产品含硫量指标,装置综合能耗主要由燃料、电、蒸汽、循环水和除盐水等构成,燃料占50%～60%;针对克石化公司装置,采用增加预加氢反应产物与装置进料换热流程的方案A,控制预加氢反应产物进分馏塔温度稳定,优化后重汽油加氢反应产物出口温度从92.0℃升至121.5℃;在方案A基础上,采用增设重汽油加氢反应产物热分离罐的方案B,能够增加精制重汽油低温热输出,按照重汽油加氢反应产物进热分离罐温度5.9℃,低温热水来水温度75℃、换热温差10℃计算,优化后装置可输出低温热169.6×10~4 kcal/h,可节约低压蒸汽2.8 t/h;在方案A和方案B基础上,采用装置进料为热进料的方案C,能够避免有效能损失,增加低温热输出,按照混合原料温度60℃计算,优化后稳定汽油输出低温热由169.6×10~4 kcal/h增加至210.9×10~4 kcal/h,折合1.0 MPa蒸汽3.5 t/h,可降低装置能耗1.4 kg/t。

Energy consumption analysis and optimization scheme of FCC gasoline hydrodesulfurization unit

Using process simulation technology, quantitative analysis of key energy consumption factors of fluid catalytic cracking(FCC) gasoline hydrodesulfurization unit were carried out on unit load, sulfur content requirements of products, composition of energy consumption and main energy consumption site, etc.Optimization suggestions were proposed for 500 kt/a FCC gasoline hydrodesulfurization unit of Karamay Petrochemical Co Ltd of PetroChina. The results showed that the main factors affecting the energy consumption of FCC gasoline hydrodesulfurization unit were unit load rate and product sulfur content index, comprehensive energy consumption of FCC gasoline hydrodesulfurization unit was mainly composed of fuel, electricity, steam, cycle water and demineralized water and so on, the fuel accounts for about 50%-60%.For the unit of Karamay Petrochemical, project A of adding heat exchanger of pre-hydrogenation reaction product and unit feed could make the temperature of the pre-hydrogenation reaction product into the fractionation column stable, and the outlet temperature of the heavy gasoline hydrogenation reaction product could be improved from 92.0 ℃ to 121.5 ℃.On the basis of project A, project B of adding the hot separation tank of the heavy gasoline hydrogenation reaction product could increase low-temperature heat output.According to the temperature(135.9 ℃) of the heavy gasoline hydrogenation reaction product into the hot separation tank, inlet temperature(75 ℃) of hot water, and heat exchanging temperature difference(10 ℃), low-temperature heat of 169.6×10^4 kcal/h could be output, meaning that low pressure steam by 2.8 t/h could be saved. Based on project A and B, project C as the hot feed scheme could avoid loss of effective energy and increase low-temperature heat output. According to the temperature(60 ℃) of mixing feedstock, low-temperature heat output of stable gasoline could increase from 169.6×10^4 kcal/h to 210.9×10^4 kcal/h, meaning that 1.0 MPa steam of 3.5 t/h could be saved and the comprehensive energy consumption of the unit could be reduced by 1.4 kg/t.