C150 – Upstream Density Calculation

Description

This calculation corrects the density to upstream conditions.

References

IP Petroleum Measurement Manuel: Part VII Section 2: Continuous Density Measurement

Implementation of ISO 5167:2003 at Gas Terminals for Sales Gas Metering Systems using Densitometers in the ‘bypass’ mode. Dti March 2007.

Kelton calculation reference C150

FLOCALC calculation reference F037

KIMS calculation reference K151

Options

Method

• Density exponent

This option calculates the upstream density using either the density or isentropic exponent as an input.

• Isenthalpic

This option calculates the upstream density using upstream and downstream temperatures and compressibility as inputs.

Density correction exponent

• Calculate from isentropic exponent

Check the box if you want to enter the isentropic exponent for use in the calculation.

Calculation

All calculations are performed in SI units unless otherwise stated.

Upstream density

When density exponent is the selcted method, the upstream density is calculated by:

Where

 ρ = Downstream density p1 = Upstream pressure Δp = Differential pressure Ed = Density exponent κ = Isentropic exponent

When isenthalpic is the selected method, the upstream density is calculated by:

 Where ρ = Downstream density (measured density at P2 T3 from the densitometer in bypass mode) p1 = Upstream pressure Δp = Differential pressure T1 = Upstream temperature T3 = Measured temperature at the downstream recovery point Z1 = AGA 8 Compressibility at P1,T1 Z3 = AGA 8 Compressibility at P2,T3

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