CUSTODY TRANSFER METERING SYSTEMS FOR GAS
A custody transfer metering system for gas is used for automated metering and definition of composition for natural gas and non-associated petroleum gas during storage, transportation, processing and custody transfer operations.
The custody transfer metering system for gas includes a set of metering devices giving information about such parameters as volume and mass flow rate, pressure, temperature of non-associated petroleum gas. The system can operate on one or several pipelines. Depending on its category and class, a gas custody transfer metering system can apply various types of flow meters: vortex, turbine, ultrasonic and electromagnetic ones, as well as flow meters based on standard restriction orifices.
MAIN FUNCTIONS OF CUSTODY TRANSFER METERING SYSTEMS FOR GAS:
- Measurements and calculations of the volume and flow rate of non-associated petroleum gas reduced to standard conditions;
- Measurement of process and quality parameters of non-associated petroleum gas (pressure, temperature and density);
- Definition of physical and chemical composition of gas (chromatography, definition of a water dew point and a hydrocarbon dew point);
- Indication of the current and accumulated values, measured and calculated parameters;
- Archiving and printout of a map of parameters, daily values of quantities and average daily values of the measured parameters.
TYPICAL COMPOSITION OF A CUSTODY TRANSFER METERING SYSTEMS FOR GAS:
- Filters unit;
- Meter run assemblies;
- Quality parameters definition unit, including: a sampling system, water dew point and hydrocarbon dew point analyzers, chromatographs, an oxygen analyzer and a density analyzer;
- Pressure control unit;
- Information gathering, processing and control system, as well as an operator workstation;
- Life support control system.
To protect from low temperatures, JSC Nefteavtomatika uses winterized modular containers equipped with exhaust ventilation, a heating system, gas detection and fire alarm systems, heated instrument cabinets and jackets in its projects.