Abstract:
The gas in the temporary section of China-Uzbekistan Gas Pipeline will be furthest imported to the A-line modified section in the process of displacement commissioning. Through the process calculation and data simulation of displacement and pressure balancing, several parameters have been determined, for example, the initial pressure of commissioning is 0.2 MPa, and gas flow rate of displacement is at 5 m/s, gas temperature in the pipeline before throttling is approximately at 12℃. And so, the temperature should drop to -31 ℃ after throttling. Based on the actual calculations result of displacement rate and the pressure changes of valve back, and the vibration situation of pipeline and equipment, the flowrate has been controlled by adjusting the total revolutions number of hand wheel. The feasibility of importing gas from the temporary section to the modified section has been demonstrated by analyzing various constraints and limitations, maximum allowable shutdown time for upstream and downstream pipeline, the optimum timing of pressure balancing etc.. Problems in displacement rate control and throttling for high-pressure gas pipeline have been solved by comparing the scheme of displacement commissioning. And the displacement commissioning process of importing gas and pressure balancing from the temporary section to the modified section have been achieved under the condition of temporary shutdown.