At our Gas compressor facility, we used to calculate final Flow throughput of the station with Orifice Metering System. On discharge line there is an Orifice plate to create Differential Pressure (DP) along with flow transmitter to transmit corresponding DP signal, a static pressure transmitters and RTD (temperature sensor) installed and above signals are transmitted to DCS.
Since 1985, these static pressure, temperature and Differential Pressure across the orifice readings are calculated in DCS and we achieved results in FLOW in accordance with (ISO-5167) and AGA-3 Orifice metering calculations.
Due to unavailability of orifice spares (like retaining rings, gaskets etc.) we could not check orifice condition till date, and we need to confirm whether our flow calculations is still valid and appropriate or require any tuning in the form of calculations, formulas etc. Please help me to calculate correct flow with under mentioned process conditions. (Please note that under mention gas compositions / calculation parameters are set from 1985)
Fluid: Natural Gas
Max. Flow: 500000 Nm3/hr
Inlet Pressure (static): 79.6 barg
Temperature: 60C
Differetial Pressure: 2500 mmH2O (98.32 inH2O)
Pipe Line: 20 inches 900lbs
Pipe inner diameter: 18.50 inches
Beta ratio: 0.6
Coefficient of discharge: 0.59768
Compressibility factor: 0.9
Upstream Density: 60.00743 Kg/m3
Mass Rate of flow: 115.13472 Kg/s
Isentropic Exponent or Specific Heat Ratio: 1.3
Dynamic Viscosity: 0.01
Reynolds (Ro): 8314.3 J/Kmolk
Since 1985, these static pressure, temperature and Differential Pressure across the orifice readings are calculated in DCS and we achieved results in FLOW in accordance with (ISO-5167) and AGA-3 Orifice metering calculations.
Due to unavailability of orifice spares (like retaining rings, gaskets etc.) we could not check orifice condition till date, and we need to confirm whether our flow calculations is still valid and appropriate or require any tuning in the form of calculations, formulas etc. Please help me to calculate correct flow with under mentioned process conditions. (Please note that under mention gas compositions / calculation parameters are set from 1985)
Fluid: Natural Gas
Max. Flow: 500000 Nm3/hr
Inlet Pressure (static): 79.6 barg
Temperature: 60C
Differetial Pressure: 2500 mmH2O (98.32 inH2O)
Pipe Line: 20 inches 900lbs
Pipe inner diameter: 18.50 inches
Beta ratio: 0.6
Coefficient of discharge: 0.59768
Compressibility factor: 0.9
Upstream Density: 60.00743 Kg/m3
Mass Rate of flow: 115.13472 Kg/s
Isentropic Exponent or Specific Heat Ratio: 1.3
Dynamic Viscosity: 0.01
Reynolds (Ro): 8314.3 J/Kmolk