提高喷管内天然气液化效率的方法

Methods of Improving the Natural Gas Liquefaction Efficiency in Nozzle

结合气、液相流动控制方程组,利用数值模拟计算,研究了利用非均质凝结及两级超声速旋流分离装置以提高天然气液化效率的可行性。结果表明,非均质凝结过程中,外界核心的存在能够有效降低气体凝结过程中的自由能障,促进液滴的凝结及生长;随着外界核心浓度的增大或外界核心半径的减小,喷管内自发凝结过程逐步被抑制,非均质凝结逐步占据主要地位;外界核心浓度的增大有利于凝结过程的发生,同时外界核心半径不能过大,外界核心半径大于1×10-7 m时,不发生非均质凝结。外界核心浓度为1×1017/kg、外界核心半径为1×10-9 m时,出口湿度较自发凝结过程湿度增加82.17%,提高了喷管内天然气液化效率。结合流量函数方法,设计了第1级超声速旋流分离装置的扩压段,在此基础上设计了两级液化过程,其综合湿度为0.107,较第1级单独使用时提高155.13%,较第2级单独使用时提高31.98%。两级液化装置较单级液化装置有更好的天然气液化效果。

Combined gas and liquid flow control equations,the feasibility of the heterogeneous condensation and two-stage supersonic swirling separation apparatus to improve the efficiency of liquefaction was studied by using numerical simulation.The results showed that the presence of outside core could effectively reduce the gas condensation free energy barrier and promote condensation and droplet growth during heterogeneous condensation process.With the increase of core concentration or the decrease of the core radius,the spontaneous condensation inside the nozzle was gradually suppressed and the heterogeneous condensation gradually occurred.The increase of core concentration was conducive to the occurrence of condensation,when the core radius could not be larger than 1×10^-7 m,to keep the heterogeneous condensation occur.The outlet humidity of heterogeneous condensation was increased by 82.17%,compared to spontaneous condensation,when the core concentration was 1 × 10^17/kg and the core radius was 1×10^-9 m.Combined with flow function method,the diffuser of first stage supersonic cyclone separation device and two-stage liquefaction process were designed.The liquefaction rate of two-stage liquefaction process was0.107,the growth rate was 155.13% and 31.98%,respectively,compared to the humidites of the first stage and the second stage.Two-stage liquefaction process was more effective for natural gas liquefaction.