The range of use of gas flowmeters in biogas
Biogas is a mixture of gases, according to the fermentation raw materials and fermentation time, the composition of the gas is different, but its main components are methane and carbon dioxide. In the normal stable gas production stage, methane accounts for 45% to 60% of the total gas volume, carbon dioxide accounts for 35% to 45%, and also contains a small amount of water vapor, hydrogen sulfide, hydrogen, carbon monoxide, ammonia, hydrocarbons, nitrogen, oxygen and methylmercaptan, in addition to containing a small amount of granular impurities.
The selection of gas flowmeter generally needs to consider the following factors:
1. Instrument performance (accuracy, repeatability, linearity, measuring range, pressure loss, upper and lower flow).
2. Fluid characteristics (fluid pressure, temperature, density, viscosity, lubricity, chemical properties, corrosion, dirt, gas compression coefficient, isentropic coefficient, specific heat capacity, miscible flow, pulsating flow, etc.).
3. Gas flow meter installation requirements (pipeline layout direction, flow direction, upstream and downstream straight pipe length, pipe diameter, maintenance space, pipeline vibration, filtration, sewage, etc.).
4. Maintenance requirements, price and other factors (purchase cost, installation cost, maintenance cost, calibration cost, operation cost, service life, spare parts). In addition to the above factors to be considered, it is very important to know exactly what is being measured (the actual situation of the biogas).
The general flow rate is about 70%-80% of the large flow rate of the flowmeter, the actual large flow rate generally does not exceed 120% of the maximum flow rate allowed by the flowmeter, and the duration is not allowed to exceed 0.5 hours, while paying attention to the lower limit of the flow range of the flowmeter, because it has a greater impact on the measurement error.
