地下储气库天然气回采的节流脱水分析

THE THROTTLE AND DEHYDRATION ANALYSIS OF RETAKEN NATURAL GAS FROM UNDERGROUND GAS STORAGE

天然气绝热节流是地下储气库回采的关键技术,可以利用节流冷效应实现回采天然气的脱水、脱油。天然气脱水后的露点与绝热节流过程有关,并且它对天然气的集输有较大影响,因此有必要利用绝热节流模型准确地分析回采天然气的节流过程。为此,利用基于BWRS状态方程的绝热节流模型计算了板876储气库回采天然气的高压节流温变等焓线。用该模型分析板876储气库的两级实际节流过程,分析结果揭示了一级节流后温度随井口压力变化的规律,确定了J-T阀(二级节流阀)前温度的安全运行范围。所得计算结果为储气库建立科学完备的生产制度提供了可靠的依据。

The adiabatic throttle of retaken natural gas (RNG) is key technology of the underground gas storage (UGS) operation. The adiabatic throttle process may be used to dehydrate the RNG. Since the dew point of the dehydrated natural gas is determined by the adiabatic throttle process and strongly affects the natural gas gathering and transportation, it is necessary to investigate the RNG's adiabatic throttle process in terms of adiabatic throttle model. At present, an adiabatic throttle model based on BWRS equation of state is used to obtain the temperature variation of Ban876 UGS's RNG at constant enthalpy condition. The model is also used to calculate and analyze the two-stage practical throttle process of Ban876 UGS. The results show that the variation of temperature after first stage throttle mainly depends on well-exit pressure and the operation temperature before J-T valve must lie in some range. These conclusions could provide credible foundation for the UGS's optimum operation.