Thermobaric compensation
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May I ask, when performing temperature and pressure compensation for gas flow rate in DCS, is it done by compensating for an ideal gas or for the gas under actual operating conditions? After a orifice plate determines the mass flow rate of the gas under operating conditions, how should temperature and pressure compensation be carried out in DCS? Does it need to be converted into the mass flow rate of an ideal gas?
Honeywell DCS: In a DCS, temperature and pressure compensation for gas flow rate is applied to compensate for the temperature and pressure conditions of the gas under operation! During compensation, the range of compensation is set in FlowComp, compensation term high limit, and compensation term low limit within the AU*LIARY module; this range is usually 80%-125%. The absolute pressure and temperature are specified in zero Ref.for pressure and zero Ref.for temperature
The pressure-temperature compensation formula is R = F * 0.5. Here, R represents the output (i.e., the flow rate after compensation), while F is the flow rate before compensation, measured in mass units. P1 is the actual measured pressure, in Mpa-g, and P0 is the pressure specified in the process parameters. T1 is the measured temperature, in °C. T0 is the process-set temperature, also in °C. The pressure-temperature compensation formula is R = F * 0.5. Here, R represents the output (i.e., the flow rate after compensation), while F is the flow rate before compensation, measured in volume units. P1 is the actual measured pressure, in Mpa-g, and P0 is the pressure specified in the process parameters. T1 is the measured temperature, in °C. T0 is the process-set temperature, also in °C.
What was mentioned above is the compensation formula for ideal gases; density compensation is relatively accurate, while full-parameter compensation is the best option.