Optimization Research And Design Of Light Hydrocarbon Sepration Process Of One Oil Field In Xinjiang

Aiming at the problem in the light hydrocarbon separation process of one oil gas filed where more device and energy are required,the mainstream turbo-expander process is used as an improvement and optimization for the original“auxiliary cooling&DHX”process,taking advantage of the high pressure of the exploited inlet oil gas.After simulation,the Residue Split Vapor（RSV）process is proved to have better material adaptability and operation flexibility where high product recovery can be achieved under different feed conditions and the operation model is easy to change.Based on the“vapor split”character of RSV process,a new process is proposed where the heat exchange between the streams is highly integrated.Taking the optimum economic benefits as the objective and the product quality and recovery as constrains,the optimization model is established.Then the SQP algorithm is organized for calculation and the optimum benefits and optimum operation conditions can be get.Afterwards,the comparison of the energy use and economy between the original and new optimized process are carried out.After heat transfer network matching,1433.3 kW heat is transferred cross the pinch point in the original process.In comparasion,the complex propane refrigeration system is saved and the hot and cold streams at different temperature range are properly matched based on the principle of“temperature match&cascade utilization of energy”in the new process.As a result,cold energy in the system is recovered and energy consumption is reduced making the overall exergy efficiency comes to 68.49%,increased by 6.7%and the operation cost is decreased from2732.6 yuan/h to 2241.8 yuan/h.Compared with the original process,the C₃⁺recovery rise from 97%to 99%and the product benefits increase from 96696.8 yuan/h to 97461.7 yuan/h.The overall benefits see an increase of 1255.7 yuan/h and there is no risk of CO₂ freezing which means that the optimized process is safe and applicable.Besides,the new optimized process can flexibly change the operation model to recovery C₂⁺and C₃⁺to accomplish higher economic benefits according to different market conditions.To sum up,this paper is based on the actual natural gas light hydrocarbon separation project.A new turbo-expander process with the“vapor split”character is proposed and the inherent law is better comprehended after modeling and optimization.The energy consumption is reduced and the energy is utilized more reasonably in new optimized process while better light hydrocarbon recovery and overall benefits are achieved.It can provide theoretical reference for the design and actual production of light hydrocarbon recovery in oil gas field.