# C261 – Gas Flowrate Conversion from Qm

## Description

This converts a gas mass flow rate to observed, standard or normal volume flow rate as well as energy flow rate.

## References

Kelton calculation reference C261

## Options

### Calculate

- Volume flow rate

- Standard volume flow rate

- Normal volume flow rate

- Energy flow rate

This allows selection of what type of flow rate mass flow rate is to be converted to.

### Calorific Value

- Volume based

- Mass based

This option allows the user to enter either a volume or mass based calorific value when calculating energy flow rate.

### Method

- Density

- Volume correction factor

This option allows the user to select whether to calculate a volumetric type flow rate using the equivalent gas density or by using a volume correction factor.

### Volume Correction Factor

- User entered

- Calculated

This option allows the user to enter a volume correction factor or have it calculated using PTZ inputs.

### Standard Density

- User entered
- Input as relative density

This option allows the user to select whether to enter standard density or enter a relative density, which will then be used to calculate standard density.

## Calculation

### Volume Flow Rate

The volume flow rate is calculated by:

If the density is calculated it is done by:

If the volume correction factor is calculated it is done by:

Where | ||
---|---|---|

P | = | Pressure at line conditions |

P_{b} |
= | Pressure at base conditions |

T | = | Temperature at line conditions |

T_{b} |
= | Temperature at base conditions |

Z | = | Compressibility at line conditions |

Z_{b} |
= | Compressibility at base conditions |

ρ | = | Density at line conditions |

ρ_{b} |
= | Density at base conditions |

Q_{m} |
= | Mass flow rate |

### Energy Flow Rate

The energy flow rate is calculated by:

If volumetric calorific value is applied:

If mass based calorific value is applied: