Optimization of verification process in national large oil/gas flowrate metering stations

In national large oil/gas flowrate metering stations, the collinear verification is normally used for meters. The feasibility study of the Urumqi sub-station project has revealed some challenges for the verification, such as high pressure, large pressure differential, complex collinear pipeline technology, and instable temperature. In this regard, this paper presents an optimized collinear verification process in gas metering by adjusting the pressure, flowrate and metering system in the substation. However, the following aspects should be considered: (1) flowrate division/adjustment system and pressure regulating system should not interact during the flowrate adjustment; (2) design should be made on the principles of "switching at constant pressure and adjusting by flowrate division"; (3) flowrate division and adjustment should enable the rapid operation to all flowrate verification points and stabilize the flowrate in a short time; (4) original collinear pipeline process, pressure regulating process and metering approach should not be changed; and (5) current metering and pressure regulating equipment of collinear pipeline should be remained to reduce the investment. The promotion and application of this optimized process in the sub-station will provide a reference to the design of other metering and verification stations in China.