A detailed introduction to the approaches for resolving measurement issues with natural gas orifice plate flowmeters

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1. Strengthen management and improve personnel competence. The reason why orifice plate flow meters tend to deviate from standards lies in the working principle and structural characteristics of the instruments themselves. Inherent errors in these instruments arise during manufacturing, while installation and usage errors are caused by factors such as corrosion, wear, and contamination of the fluid medium during installation or over time of use. Therefore, the flow measurement system should be installed strictly in accordance with technical requirements to eliminate installation errors. During use, operators should carry out proper inspection, maintenance, and upkeep of the system to extend its service life and reduce measurement errors. At the same time, in practical applications, efforts should be intensified to promote and implement standard SY/T6143-19%. The \"Standard orifice plate measurement method for natural gas flow rate\" (SY/6143-1996) mentions methods to reduce errors. As specified in the appendix \"Handling of Partial Deviations from Standard Requirements in the Use of Throttling Devices,\" in practical applications it is possible to add two correction factors to the discharge coefficient c, namely the orifice inlet sharpness correction factor and the pipe wall roughness correction factor, or to use throttling devices with interchangeable orifices. Therefore, in the practical application of natural gas metering, in-depth research is necessary to fully understand the essence of the \"Standard Orifice Plate Metering Method for Natural Gas Flow\" (SY/T 6143–1996). It is essential to install, use, and process data in strict accordance with the standard requirements in order to ensure the accuracy of natural gas metering. 2. Proper selection of measuring instruments Standard throttling devices should be the first choice for measuring instruments. When the flow rate varies significantly, wide-range intelligent differential transmitters should be considered. Other types of measuring instruments should be selected with caution when used in standards for natural gas measurement. The measurement models of secondary instruments should comply with the requirements of SY/T 6143-19%, enabling the calculation of Fz and the input of component values, as well as the real-time calculation of the c value. 3. Strengthen technical training and draw on foreign experience; introduce, digest, and absorb the new natural gas metering technologies that have been developed in recent years. Looking at the situation abroad, in international natural gas trade, energy measurement has almost completely replaced traditional volume measurement, whereas in China’s natural gas measurement sector, volume measurement still holds a dominant position. In order to keep up with international standards as soon as possible, the users can collaborate with various research institutes to carry out experiments on natural gas energy metering, and establish standards on this basis. To accelerate the progress of testing, it is recommended to introduce advanced foreign online gas chromatography systems and flow computers, and to develop a natural gas energy metering system suitable for China’s national conditions based on the assimilation of these imported technologies.