The following application concerns the removal of H2S from a water saturated CO2 gas stream that was produced from an alkanolamine sweetener.
A natural gas plant located in the northwestern New Mexico, removes acid gas with alkanolamine absorption and regeneration. The resulting acid gas rejected in the regenerator vent contains over 99 percent CO2 and as much as 150 ppm H2S.
Reducing the H2S concentration to 10 ppm or less permits the gas to be discharged to the atmosphere.
ENVIRO-SCRUB® is injected via an atomizer into a horizontal line just ahead of a static mixer in the rich amine feed to the regenerator. Before the CO2 reaches the contact tower, the H2S concentration drops from 150 ppm to 40 ppm. The remaining H2S is removed in the regenerator.
The contact tower is on liquid level control. The 10 ppm permit H2S level is easily achieved and the air is discharged into the atmosphere. The spent ENVIRO-SCRUB® is disposed of in permitted disposal wells. This continuous system has
produced substantial economic benefits for the customer.
Gas Flow Rate : 5 MMScfd
Gas Composition: 99 + % CO2
Pressure: 17 – 21 psig
Incoming H2S: 150 ppm
Outgoing H2S: 0-7 ppm
Consumption: 0.035 to 0.040 gallons per ppm H2S per million Scf. 2.11 to 2.41 lbs. per gallon of product.