Simulation Of Crude Distillation Process And Analysis Of Heat Transfer Potential

Crude distillation is the first process of petroleum processing,and the energy consumption is high,so the energy-saving analysis of atmospheric and vacuum distillation is particularly important.At present,the optimization of the heat exchange network using the pinch point technique at atmospheric and vacuum distillation has achieved good results,but whether the process of atmospheric and vacuum distillation has further optimization potential is still a problem worth studying.According to the process and calibration data of a plant’s atmospheric and vacuum distillation unit,this paper uses PRO/II process simulation software to simulate the whole process of the atmospheric and vacuum distillation unit.Comparing the simulation results with the actual data of the plant,the mass transfer efficiency of different tower sections of the atmospheric and vacuum tower was calculated,and the reasons for the different mass transfer efficiencies of each tower section were analyzed.According to the thermodynamic theory,at the same temperature,the pressure of the heat exchange stream is increased,the heat exchange flux is lowered,the heat of the product cannot be more effectively utilized,and the lift of the pump is increased,which is not conducive to the energy utilization of the device.Aiming at the heat exchange network in front of the first distillation(flash)tower,the influence of pressure on the vaporization rate of crude oil and the effect of the pressure scheme currently used on the heat transfer effect and the subsequent normal pressure furnace load were studied.The results show that when the inlet pressure of the heat exchanger rises to 1.65 MPa,the vaporization rate can be reduced to 0.At this time,the heat load of the atmospheric pressure furnace is increased by 2.06%,the heat load of the heat exchanger before the furnace is increased by 5.09%,and the atmospheric pressure tower top is condensed.The load increased by 2.38%,the cooling water consumption increased by 2.4%,and the pump power increased by 0.61 Mk J/h.In this paper,the two-stage flashing method is used to solve the problem of crude oil vaporization by replacing the pressurization scheme with a light component load transfer technology.Comparing the conventional operation,pressurization and secondary flashing,the results show that if the secondary flashing is used,the effect of pressure on the vaporization of crude oil can be solved,and the low-temperature heat can be recycled more.Save about 8.2%.In addition,the secondary flashing scheme can also reduce the water content of the bottom of the flashing tower,and is more suitable for the fluctuation of the water content of the crude oil,so that the device can run smoothly.In this paper,the energy consumption of each operating unit is taken as the research object.Combined with the design experience,the influence of different vaporization rates on the energy consumption of each operating unit is discussed.The results show that the vaporization rate is between 2% and 3%,which is beneficial to the energy saving and consumption of the device and the long-term operation of the heat exchanger.