h2s conversion

[cameron54]

how is the 7420 derived in the following equation?

(h2s ppm x air flow cfm)/7420 = lb/day h2s

 

[bimr]

Air Release = (volumetric flow, m3/s)(concentration, mg/m3)(operating time, s/day)

1 ppm H2S = 2 mg/cubic meter at STP since the molecular weith of H2S = 34.08 g/mol. Note that this has to be converted to actual operating temperature and pressure.

The rest of the number are unit conversions. See the examples:

http://www.lenntech.com/calculators/converter-parts-per-million.htm

http://www.epa.gov/tri/TWebHelp/WebHelp/appendix_b_basic_calculation_techniques_4.htm