中乌天然气管道A线绕行段天然气置换投产

Displacement commissioning of the A-line modified section of China-Uzbekistan Gas Pipeline

中乌天然气管道A线绕行段置换投产需最大程度地将临时段管道中的天然气导入A线绕行段管道。对置换和平压过程进行工艺计算和数据模拟,确定投产初始压力为0.2MPa,天然气置换流速为5m/s,管内天然气节流前的温度约12℃,节流后的温度将降至约-31℃。根据实际置换速率的计算结果、阀后压力的变化以及管道、设备的振动情况,调整手轮总转数以控制流量。通过分析约束条件、上下游允许的最大停输时间、平压作业的最佳时机,论证了将临时段内的天然气导入绕行段的可行性。通过对不同置换方式的工程实施方案进行比选,解决了高压天然气置换过程中高压差节流、置换速率控制的难题,实现了临时停输情况下临时段管道向绕行段管道导入天然气并最终平压的置换投产。

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.