The Gas Research Institute (GRI) is sponsoring an evaluation program for hydrogen sulfide (H2S) scavenging technologies as part of an overall sulfur removal recovery research program. The evaluation of liquid-based scavenging processes in batch tower applications was the first in a series of full-scale field evaluations. This paper discusses the results of the initial field evaluation which was conducted at a natural gas production plant in South Texas treating 16 MMSCFD of natural gas with 19 ppmv H2S and 0.5 percent CO2 at 1000 psig.
Three types of commercial scavenging agents were evaluated: nitrite, nonregenerable amine, and triazine. All three types met the treatment specification of 4 ppmv H2S. Capacities ranged from about 0.60 lbs sulfur per gallon of scavenging agent for the nonregenerable amine and triazine agents to about 0.75 lbs/gallon for the nitrite agent. Foaming was encountered with all of the agents and was controlled to manageable levels with defoaming additives. Overall treatment costs including capital recovery and operating costs ranged from about 0.037/MSCF for the nitrite agent to about $0.051/MSCF for the nonregenerable amine and triazine agents, based on treating gas containing 19 ppm H2S. (Operating costs will increase nearly in proportion to H2S concentration.)