Numerical modeling of the dynamic filling process of high-pressure tankers for marginal gas wells

摘要

In this paper, a new mathematical model is developed to accurately simulate the dynamic filling process of high-pressure tankers for marginal gas wells. The hydrodynamic and thermodynamic equations, and the thermodynamic properties of wet gas are assembled to represent the process elements, including gas wells, high-pressure tankers, connecting pipes and resistance elements (i.e., choke valves and heaters). Based on the damped Newton-Raphson method, a quasi-steady solution procedure is proposed to solve this model. The reliability of the proposed model is validated against experimental data obtained from a marginal gas well. The volumetric flow rate at the standard condition, the fluid velocity at the outlet of the choke valve, the fluid temperature and hydrate formation temperature after the heater are investigated. Moreover, the parameters including the mass flow rate, the charged mass, and the total filling time are calculated to determine the high-efficient filling period. The results show that the numerical results of present work are in good agreement with the experimental data. This model provides an effective approach to determine the maximum handing capacity, inlet and out diameters of the separator, and the outlet temperature of the heater. Also, the high-efficient filling period and the operation time of compressors could be obtained to optimize the number of high-pressure gas tankers and to enhance the economic benefits. This model could further be applied to the refueling process of compressed natural gas (CNG) or compressed hydrogen gas (CHG) in refueling stations by use of different equations of state (EOSs).