Sample Calculations for Figures C-1 through C-4

The following calculations may be used to estimate vol­ume and mass of hydrogen sulfide when total gas volume and its hydrogen sulfide content are known:

Continuous Release.

Assume: Release of 5,000,000 SCFD of natural gas con­taining 8,000 ppm (by volume) of hydrogen sulfide.

Note: The user must know both the volume (or flow rate) of natural gas and its hydrogen sulfide concentration so that Figures C-I through C-4 can be effectively used.

To determine standard cubic feet per hour (SCFH) of hy­drogen sulfide released, the following calculations should be performed using appropriate values for the conditions being evaluated:

5,000,000 SCFD x 8,000 ppm H₂S

24,000,000 - 1,667 SCFH of H₂S released.

To determine the pounds of hydrogen sulfide released per hour, the following calculations should be performed using appropriate values for the conditions being evaluated:

5,000,000 SCFD x 8,000 ppm H₂S

267,605,634 - 150 lb/hr of H₂S released.

Instantaneous Release.

Assume: Release of 100,000 SCF of natural gas contain­ing 8,000 ppm (by volume) of hydrogen sulfide. Also, as­sume this example is a daytime release, 5 miles per hour

wind speed (refer to Figure C-3).

To determine the volume (SCF) of hydrogen sulfide re­leased, the following calculations should be performed using appropriate values for the conditions being evaluated:

100,000 SCF x 8,000 ppm H2S

1,000,000 - 800 SCF of H₂S released

After applying the appropriate calculations and using known factors to arrive at either hydrogen sulfide release rate or quantity of hydrogen sulfide released, refer to the appro­priate chart (Figs. C-1 through C-4) or the equation in Par. C.8 (example calculations in Pars. C.9 through С12) for ob­taining radius of exposure (ROE) information.

The following equation can be used to convert percent hy­drogen sulfide to parts per million on a volume basis:

Percent H₂S x 10,000 - ppm H₂S