Natural Gas Flow Computer (SGERG) - Analogue Flow

The 515 GN12 application measures the volume, mass and gross heat content of natural gas by using analog volume flow, temperature and pressure inputs.

The Flowmeter input signal can be selected as either 0-5V, 1-5V or 4-20mA. Minimum and maximum points are programmed and non-linear correction points can be used to better reflect the flowmeters behaviour.

The SGERG calculation (AGA-8 Detail Characterization Method) is used to obtain accurate values of density and compressibility factors for the flow calculations.

CALCULATIONS

The gas density and compressibility factor calculations are based on the AGA-8 equations. The calculations are valid for the region:

-8.0°C < t < 62.0°C P < 12MPa

17°F < t < 143.0°F P < 1740psia

FORMULAS

Mflow = volume flow• ρflow

corrected flow = Mflow/ρ ref

Heat flow = Mflow•Hm

Where:

Mflow = mass flow

ρflow = density at flow conditions

ρ ref = density at reference conditions

Hm = mass gross heating value