天然气调压设备及其热力学完善性分析

Gas Pressure-regulating Equipment and Analysis on Its Thermodynamics Perfection

透平膨胀机、涡流管、节流阀是高压天然气进入城市燃气输配管网的典型的调压装置。以概念为基础,以平衡为工具,对涡流管、节流阀、透平膨胀机这3种燃气调压装置进行全面的热力学分析。结果表明,透平膨胀机的过程损失最小,效率最高,显示出其在调压过程中的热力学完善性;涡流管具有较好的气液分离效果,可以较好地脱除燃气中的水分,且当入口温度较高时,损失明显减少,可以考虑用其替代透平膨胀机;随着入口温度的降低,透平膨胀机的优越性随之下降,可以考虑用节流阀代之。

Turbo expander, vortex tube and throttle are typical pressure-regulating devices for high-pressure gas entering the pipe network of urban gas transmission and distribution. Based on exergy concept and exergy-equilibrium theory, a comprehensive analysis of thermodynamics has been carried through for the 3 devices above. The result indicates that turbo expander has the lowest exergy loss and the highest efficiency, showing the thermodynamics perfection during pressure regulation. Vortex tube has a better separating effect on removing liquid from gas; when high temperature appears at the entrance, the exergy loss reduces obviously; so, it can be considered to replace the turbo expander. With the entrance temperature decreasing, the advantage of turbo expander decreases, therefore, throttle can be considered to replace it.