Erosion simulation and improvement scheme of separator blowdown system ——A case study of Changning national shale gas demonstration area

Abstract

In the shale gas vertical separation metering skid, after the shale gas is separated by the gas-liquid separator, the bottom sand-carrying sewage is driven by high pressure, and the high-speed flowing sand particles will cause serious erosion to the sewage valve. Given this problem, taking a production well in the Changning area as an example, the corresponding mathematical model, and a three-dimensional model of blowdown valve is established. Based on FLUENT flow field analysis software, the erosion of the blowdown valve is simulated and analyzed under different pressure, sand particle size, and shape factor, sand particle density, and sewage sediment concentration, and the serious erosion problem of the blowdown system is obtained. Therefore, a new blowdown system improvement scheme is proposed, and the erosion of the blowdown valve after the scheme operation is simulated. The results show that the maximum erosion rate of the improved blowdown valve is 1.024 × 10−6kg/(s·m2), and the converted annual erosion thickness is 57.4 μm, which is 26.538–61.247 mm compared to the unimproved sewage valve. The corrosion inhibition rate of the sewage system can reach more than 99%. This greatly reduces the erosion rate of the blowdown valve and ensures the safe operation of the equipment.