As a clean energy, natural gas has been increasingly utilized, and its proportion in the energy structure is increasing year by year. With the progress of my country's west-to-east gas transmission project, the coverage of natural gas is becoming more and more extensive, so the measurement of natural gas flow has become an important link.
The flow measurement of natural gas is currently used in trade settlement, and the measurement of natural gas trade in my country is basically based on volumetric measurement at this stage. At present, the flow meter products used for natural gas flow measurement include: gas waist wheel flow meter, gas turbine flow meter, precession vortex flow meter, vortex street flow meter, etc. Let's make a simple comparison of these flow meters.
1. Vortex flowmeter
How vortex flow meter works：Vortex flow meters are generally used in the internal assessment of natural gas in industrial and mining enterprises and the measurement of energy consumption.
Advantages of vortex flow meter: The overall structure design is reasonable, the dynamic measurement range is wide, and the pressure loss is small; the main body of the instrument can be made of stainless steel, which is suitable for the measurement of corrosive media; the instrument has no moving parts, and the installation and maintenance are simple
Disadvantages of vortex flow meter: afraid of vibration, afraid of electromagnetic interference. It is recommended to purchase a vortex street with good shock resistance and anti-interference.
2. Gas turbine flow meter
The customized gas turbine flow meter is the most frequently used natural gas flow measuring instrument at present.
Advantages: simple structure, easy installation; relatively small dimensions; high precision; good repeatability
Disadvantages: The turbine rotates at high speed, and the mechanical friction between the bearing and the shaft requires regular replenishment of lubricating oil. In addition, if the high-speed flowing gas contains large solid particles, it is easy to damage the turbine blades, and a filter should be installed on the pipeline before the meter.
3. Precession vortex flow meter
The precession vortex flow meter is a commonly used flow meter product in some small natural gas distribution stations in China.
Advantages: wide working temperature range; large range; not affected by fluid temperature, pressure, density and viscosity; strong applicability, generally no need to install filters except for impurities containing larger particles or longer fibers; direct upstream and downstream The requirements for pipe sections are relatively low, just take the upstream 4D and downstream 2D straight pipe sections
Disadvantages: large pressure loss, and secondly, it is more sensitive to pipeline vibration and electromagnetic interference, so it is recommended to purchase a precession vortex flow meter with anti-seismic and anti-interference performance.
4. Gas waist wheel flowmeter
The gas waist wheel flow meter, also known as the Roots flow meter, can be used not only to measure dry gas, but also to measure wet gas (that is, associated gas).
Advantages: Insensitive to flow pulsation.
Disadvantages: The waist wheel is noisy when it rotates at high speed.