Study On Solid Particle’s Trajectory And Deposition In Gathering System Of Natural Gas

As an important high-quality energy and chemical raw material, natural gas plays an important role in the industrial and national production. In the natural gas gathering and transportation system, there are a variety of solid particles, these particles will deposit with the transportation of natural gas in some special pipe of gathering system, causing blockage and damage on gathering system pipe and equipment.In this paper, the flow of high-sulfur gas containing solid particles in the gathering system has been studied and the particle trajectories and deposition has been simulated. Main works and conclusions are as follows:Using the principle of corresponding states based on the model of LJ fluid, gas properties were calculated and accurate calculation program of gas density and viscosity was compiled The result shows that the calculation method can calculate gas density and viscosity under high pressure(13.96 MPa) and the error is under 1.5%.Commercial software was used to simulate the flow field of the gas containing solid particles in a horizontal pipe, elbow pipe, variable diameter tube and T-tee tube four common pipes, respectively. Trajectories of the solid particles were simulated, and the deposition rate and the deposition rate were calculated. The results showed that: the deposition rate and the deposition velocity of the particles within the tube section increases with the particle diameter and density increasing, and once the particle diameter is larger than 300μm, it will soon deposited on the wall. The deposition rate and the deposition velocity decrease at first then increase with the rise of gas temperature, decrease with the increase of natural gas pressure, decrease with increase of the gas flow velocity; particle deposition velocity is closely related to the particle relaxation time and decreases at first then increases with the increase of particle relaxation time. Particles deposition occurred obviously on the elbow pipe, variable diameter tube and T-tee tube. For elbow pipe, the particles were more easily deposited after the bend. For variable diameter tube, particle deposition rate increases with the increase of variable diameter ratio; under the same conditions, the deposition rate is closely related to the expansion angle and with the expansion angle from 10o to 90o changes, the deposition of particles increases and reaches maximum at 45o. For T-tee section, deposition rate of particles increase at first then decrease with the increase of diameter ratio(0.4-1.0); particle deposition rate of branch pipes are more susceptible to a variety of factors.