Metering System
About LNG Industry
Natural gas is normally transferred from the producing country via LNG carrier or natural gas pipelines, stored in the storage tanks of LNG production base, and then sent out through a pipeline network. This way, the gas is supplied to the plant owners utilizing natural gas after a consultation with LNG suppliers. Herein, metering system is a critical requirement to measure the amount of gas flow.
About Metering System
A Metering System measures the amount of gas flowing through pipelines. It allows to continuously record and transmit the measurement data to a control room or any higher agencies. The measurement may include data such as flowrate, compositions, density, and hourly cumulative amount.
Metering system is commonly comprised of Flowmeter, Flow computer, Gas Chromatography, Transmitter, MOV (Motor Operated Valve) and other various hardware such as valves and more. TaeChin SMET specializes in system integration and commissioning of the metering system.
Technical Note
As per design standards for natural gas metering facilities of KOGAS, use of Orifice flow meter is the basic standard. In case of high capacity orifice flow meter, it basically consists of 4 rows of meter run, each meter run having its own MOV. Depending on the flow rate, meter run change is automatically performed by the PLC of the Flow computer Panel, and the status of each meter run can be monitored on the HMI via Flow Computer in real time.
Flow meter
Orifice
How to measure
Measures the flow rate by measuring the differential pressure between the front and rear ends of the Orifice installed in the pipe.
Special feature
It has a simple structure and is easy to calibrate, but due to pressure loss issues, it is necessary to be installed in multi column and requires meter tube over a certain length.
Ultra Sonic
How to measure
Measures the flow rate by measuring the differential pressure between the front and rear ends of the Orifice installed in the pipe.
Special feature
It has high precision and less footprint compared to other types
Turbine
How to measure
Measures the flow rate by measuring the rotor’s rotation speed according to the flow inside the pipe
Special feature
It is economical and requires a relatively small footprint, but requires periodic calibration and maintenance due to installation of peripheral equipment
Transmitter
Transmitter is installed in the field along with flowmeter to measure pressure, temperature and the differential pressure of the front and rear ends of the orifice in the process pipe and sends the data to the Flow Computer.
Flow Computer
Flow Computer receives from Field Transmitter various data such as process differential pressure, pressure, temperature and gas composition data from gas analyzer. It calculates density, calculates mass, volume, energy flowrate, and integrates all calculated values as per international standard. Data generated by Flow Computer and data collected in Field are transmitted to HMI computer by communication in real time and processed into user's desired data and transmitted through modem and dedicated line.
Gas Chromatograph
Gas Chromatograph takes sample from the process line through sample probe, accurately measures the gas components in the process, and then transfers the gas component data to the flow computer.