Estimation of the indicators for instrument consumption in the automatic control valves (including shut-off valves) of process units
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I would like to ask my colleagues: what is the typical consumption of instrument air for automatic control valves (including shut-off valves) in process units? This value affects the capacity of the instrument air compression station.
The specification is 2 Nm3/h, but in practice it’s not that much
A control loop for a regulating valve consumes 1 Nm3/h of instrument air (purified air). I asked the instrumentation specialists in our department, and they all follow this approach: by counting the number of loops on the PID diagram, you can determine the total air consumption.
2 Nm3/hr per control valve or KV (6 strokes)
It is generally considered to be 4 Nm3/h per unit.
It is generally considered to be 5 Nm3/h per unit.
Among the answers provided by our enthusiastic friends, we have 1 Nm3/h, 2 Nm3/h, 4 Nm3/h, and 5 Nm3/h. Why are there so many different standards? Which one is correct?
Grade 2 is relatively standard, but its usage in practice is very limited; if certain considerations come into play, it can be handled by using Grade 1, and there will be no major issues in practical applications
According to the SH3020-2001 Design Code for Instrument Air Supply in Petrochemical Industries, the air consumption per control valve is taken as 1–2 Nm3/h. For the design capacity of the instrument air supply system, LZ is requested to refer to SH3020-2001 for calculations and design