Optimization Research On Pressure-decreasing Operation Of Low-pressure Steam In Changling Refinery Based On Three Links Of Energy

Improving the efficiency of energy utilization and greatly promoting energy saving are important ways for production enterprises to reduce costs and increase economic efficiency.The comprehensive energy consumption of refinery enterprises is very high.Steam,as the main energy source of refinery enterprises,is wasted in varying degrees during production,transportation,use and recovery.Steam power system optimization has great potential,but domestic research on energy-saving transformation of steam system is insufficient.The research mainly focuses on the steam pipe network pipeline transformation,and there are few studies on the optimization of low-pressure steam depressurization operation.There is a large amount of steam in the old and new Changling Refinery and Chemical Plant.Among them,1.0 MPa low pressure steam is the main steam source of each unit,and it is the focus of optimization and energy saving of steam system.Based on the three-link energy model,the low-pressure steam system of Changling Refining and Chemical Company is divided into three parts: energy conversion,energy utilization and energy recovery.The paper establishes the balance model of low pressure steam system for each link and determines its energy balance and evaluation index.The steam system of Changling Refinery is a cogeneration system.Using the operating parameters of Changling 1.0 MPa low pressure steam system to calculate the rake loss and rake efficiency in the three links of energy utilization.It was found that the efficiency of the low pressure steam system in Changling Refinery and Chemical Company was bad,and the main factor of the loss is the energy conversion link in the low pressure steam system.The results show that 1.0 MPa low pressure steam depressurization operation may cause slight changes in parameters such as power generation capacity,steam pressure,temperature utilization rate and the operation of pipeline network,but it will not cause restrictive effects on the steam used in the unit.The results show that 1.0 MPa low pressure steam depressurization operation may cause slight changes in parameters such as power generation capacity,steam pressure,temperature utilization rate and the operation of pipeline network,but it will not cause restrictive effects on the steam used in the unit.The direction of optimization and transformation of low pressure steam system in Changling Refinery and Chemical Company is to adjust the steam temperature and reduce the pressure of the pipeline network.According to the actual production data,the steam system is calculated.The reasonable operation parameters of the pipeline network are obtained as follows: pressure 0.8MPa,steam temperature 290?.Based on the analysis results of energy three links,the paper put forward the implementation scheme of pressure reduction operation of low pressure steam system in Changling Refinery and Chemical Industry.The pressure reduction operation was carried out in three areas respectively.The back pressure of No.1 catalytic gas compressor and coking gas compressor in Eastern District was reduced from 1.0 MPa to 0.8 MPa,and the output of1.0 MPa was reduced by 11.9 t/h by the separate supply of sewage stripping in Eastern District;the steam used in South District Hydrotreating sewage stripping and No.3atmospheric and vacuum distillation unit came from the special line of reforming,and the back pressure of steam turbine in No.3 catalytic and diesel hydrotreating unit was reduced from 1.0 MPa to 0.8 MPa,and the steam output of 1.0 MPa was reduced by 9.9 t/h after optimization.The efficiency of the whole cogeneration system is 65.99% after optimization.The annual benefit after the step-down operation is about 3.062 million yuan.