Secondary standard device and method for natural gas large flow real flow calibrating

Abstract

The invention provides a secondary standard device and method for natural gas large flow real flow calibrating. The device comprises an upstream header, a downstream header, and fifteen critical flownozzles which are parallel arranged; lower ends of the critical flow nozzles are communicated with the downstream header, and upper ends of the critical flow nozzles are communicated with the upstreamheader; rectifiers are arranged at the upstream of the critical flow nozzles, and telescopic devices are arranged at the downstream of the critical flow nozzles. During the designing process of the Yulin calibrating post of the National Oil and Natural Gas Large Flow Metering Station, calibrating of a working-level standard flow meter and other high-precision flow meters is achieved by adopting the device. A tube capacity of 1.3m<3> is reduced during small flow calibration, the uncertainty of systematic measuring when calibration is performed is improved, the number of zero-leakage forced sealing ball valves is reduced, the device investment cost is reduced by approximately 500,000 dollars and the valve maintenance cost is reduced by 200,000 dollars per year.

Description

technical field [0001] The invention belongs to the field of natural gas metering, in particular to a secondary standard device and method for large-flow real-flow verification of natural gas. Background technique [0002] 1. The situation of domestic actual flow test quantitative value transfer system [0003] At present, large and medium-caliber (DN200 and above) natural gas metering flowmeters such as ultrasonic flowmeters, turbine flowmeters, etc. (inspected flowmeters) for domestic trade transfer use the standard meter method (working standard) for real-flow compulsory verification and calibration. The system uncertainty of the working standard can reach 0.33%, and the standard meter generally adopts a 0.25-grade high-precision gas turbine flowmeter. For the actual flow mandatory verification and calibration of the standard meter, because the critical flow nozzle has stable critical flow characteristics and high outflow coefficient uncertainty, the domestic natural gas...

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Problems solved by technology

[0014] In order to overcome the existing problems of low verification accuracy and high cost and investment, the present invention provides a secondary standard device and method for large-flow real-flow verification of natural gas. The present invention optimizes the form of the secondary standard device to reduce small The pipe capacity of the upstream manifold during flow verification improves the verification accuracy; reduces the number of shut-off valves and reduces investment and maintenance to a certain extent

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