Is the flow rate measured by the flow meter under operating conditions or standard conditions?

It is generally necessary to display and record under standard conditions

This post was last edited by huio1983 on 2015-6-26 07:59. Standard conditions refer to the state at zero degrees or 20 degrees Celsius under one atmosphere of pressure; this is used for calculations. When conversion is necessary, density compensation and temperature-pressure compensation are often applied to bring the values back to standard conditions. The operating conditions refer to the state of the flow meter under its designed or calibrated conditions, that is, the actual temperature and pressure. As required, these values are compensated to correspond to standard conditions for flow rate; when in use, compensating for the designed pressure and temperature is sufficient to achieve standard conditions. Under standard conditions, the calculation can be done within the DCS, or by an integrator. There are formula conversions; these generally refer to gases, and some liquids do not necessarily turn into gases at very high pressures. For natural gas, the conditions at standard temperature are basically the same as for others. The operating conditions are converted to standard conditions; first, refer to the calculation sheet, and the unit after conversion is Nm3/h, which represents standard conditions

The ratio of the volumetric flow rate under operating conditions to the volumetric flow rate under standard conditions is inversely proportional to the ratio of their densities, as given by the following equation: Volumetric flow rate under operating conditions / Volumetric flow rate under standard conditions = Volumetric density under standard conditions / Volumetric density under operating conditions (Standard conditions for industrial gases: temperature of 20 degrees, pressure of 0.101325 MPa)

Standard conditions apply only to gases; the essence of temperature and pressure compensation is to compensate for the density of the medium. The flow rate measured by a flow meter is usually the flow rate under actual operating conditions, and it is more convenient to convert it to standard conditions in a DCS.

1. Are the flow rates measured by various flow meters used in daily operations based on standard conditions or actual operating conditions? Things like orifice plates, vortex flow meters, mass, and so on… For measuring gas flow, it is necessary for the gas to be compressible, as its volume changes under different pressures and temperatures. For ease of management, standard cubic units are used for calculations. 2. Is it only gas flow measurement that has standard conditions and operating conditions? Liquids also have these, but since the volume of liquids changes little with temperature and pressure, there is no need to distinguish between standard conditions and operating conditions for them. 3. When is temperature and pressure compensation, or density compensation, used? And how is it carried out (in a DCS)? What is the purpose? Is it to ensure the output is at standard conditions? ? Or what? Since the density of gases varies under different temperatures and pressures, compensation is necessary, which essentially involves compensating for that density change. Compensation is carried out in the DCS or flow integrator (which includes the corresponding mathematical models), and the standard conditions are displayed as the cumulative value after conversion by the DCS or flow integrator. 4. Are the standard conditions for measuring flow rates of natural gas different from those of other gases? ? Gases are all the same; standard conditions refer to 20°C and one atmosphere of pressure. 5. It has been determined that a certain gauge measures the flow rate under operating conditions; how can it be converted to standard conditions? Do I need to convert it? Once the parameters of the flow meter are set, the flow rate under standard conditions is displayed, eliminating the need for manual calculations. 6. What does density have to do with what I mentioned above? How do I set it up? Carefully read the parameter settings in the flow meter’s user manual, and then make the settings yourself according to the instructions.....

I think: with the internet being so advanced these days, the original poster can definitely learn the basics on their own first. It’s better to ask if there are really any unclear points – it’s also a way of showing respect for others. Only by studying the relevant knowledge through one’s own system can one fully understand the responses in that section.

Isn’t the standard condition for gas flow rate 0 degrees? Natural gas is at 20 degrees, but some is also at 0 degrees.

It is usually 20°C; there are also cases where it is 0°C. Is the correct value the standard conditions (20°C, 1 atmosphere) or (0°C, 1 atmosphere)?

When I was in school, the standard conditions referred to 0 degrees and 101.325 kPa. When I first started working with natural gas, there were terms like standard-condition flow rate and actual-condition flow rate. After doing some calculations, I found that the standard conditions refer to a temperature of 20 degrees and a pressure of 101.325 Pa. In summary, when it comes to standard conditions at present, there are two explanations, and I absolutely approve of them!