# Emission estimation calculators, booklet 1: chapter 13

## Sulphur Dioxide (SO2) from Burning Sour Gas

This calculator is to assist with estimating the releases of sulphur dioxide from the burning of sour natural gas.  This calculation deals only with the conversion of hydrogen sulfide to sulphur dioxide. The following natural gas combustion calculators are available on the National Pollutant Release Inventory toolbox: external combustion boilers, internal combustion engines, and biogas flaring for natural gas with less than 80% methane.  Note that the combustion spreadsheets will also calculate a value for sulphur dioxide, however the value calculated here should be used instead as it will more accurately represent the actual release.

### Methodology used to develop calculations

Mass balance and stoichiometric information was used to develop the relationship between the concentration of hydrogen sulfide (H2S) in the natural gas being burned and the amount of sulphur dioxide (SO2) released to the air.

#### Input

A = activity (in this case the mass of H2S burned) [kilograms]
B = volume of H2S burned [cubic meters]
C = percentage of H2S in the gas by volume
D = destruction efficiency [%]
H = heating value [Giga Joules/cubic meter]
J = amount of sour gas burned [cubic meters]
K = amount of sour gas burned [Giga Joules]

If the amount of sour gas burned is not known in cubic meters you can convert the amount in Giga Joules using the following equation:

J = K/H

The conversion above is based on a default heating value (H) of 0.0386. If a site specific heating value is available please use that instead.

The volume of H2S burned is given by the equation:

B = J x C x D

The mass of H2S burned is then calculated by:

A = B x 1.44114915367

#### Equation to calculate the amount of Sulphur Dioxide Released

E = A x (64.0588/34.07588)/1000

where,

E = emission of sulphur dioxide (CAS 7446-09-5Footnote1) [tonnes]