Simulation and analysis of light hydrocarbon recovery combined with LNG helium extraction process
In order to reduce the energy consumption and equipment cost of helium extraction in a single process and make full use of the cooling energy provided by nitrogen cycle expansion refrigeration,the direct heat transfer(DHX)process for light hydrocarbon recovery,with self-produced refrigerant refrigeration+expansion refrigeration+cooling box integrated heat transfer,is combined with the low temperature natural gas helium extraction process to design a co-production process for producing C3+,crude helium and LNG simultaneously.Through analyzing the influencing factor of key parameters,it is determined that the pressure at the outlet of the expander is 1.2 MPa,the reflux temperature at the top of DHX tower is-70℃,the feed temperature for the first-stage helium-extracting tower is-50℃,the pressure at the outlet of the compression pump is 5 MPa,the feed temperature for the cryogenic separator is 35℃,and the refrigerant flow rate is 4 000 kmol·h-1.Simulation results show that the recovery rate of C3+is 78.95%,the recovery rate of crude helium is 93.77%,the concentration of crude helium is 60.43%,and the output of LNG is 663.84 kmol·h-1.In addition,total compressor energy consumption of the co-production process is 12.95%lower than that of the single process,and the unit comprehensive energy consumption is 14.10%lower.Study shows that the light hydrocarbon recovery combined with LNG natural gas helium extraction process has great advantages in energy consumption and investment cost,presenting a certain investment value.
万方数据
维普
