Advanced Technologies Create New Process For Removing H2S By John C. Bourdon, Peter J. Photos and F. Hailey Brown SAN ANTONIO-As existing natural gas wells age, hydrogen sulfide will become a greater concern for operators, and there will be increased need in the future to find effective solutions. Reduction-oxidation (REDOX) chemistries to eliminate H2S from natural gas provides a number of advantages over traditional scavenger and amine-based processes, but the commercialization of REDOX chemistries has been limited by significant operational and economic challenges. The introduction of new chelants, surfactants and low-cost computing devices is enabling a new approach that eliminates many of the operational challenges of the past. The new REDOX process employs advanced regenerative chemistries and control systems in self-contained automated units to cost-effectively remove H2S from natural gas streams.The automated units can be delivered to the field rapidly, and are capable of operating on scales ranging from single wells to entire fields. The technology provides an operationally sustainable and commercially attractive alternative to standard H2S removal methods such as amine-based sulfur recovery units or chemical scavengers. Oxidation-reduction chemistries have long been an attractive option for H2S removal, with lower capital costs than sulfur recovery units or acid gas injection wells and a fraction of the operating costs of scavengers. Balancing capital expenditures versus operating expenses has been difficult for producers with smaller quantities of H2S that need to be removed. 56 THE AMERICAN OIL & GAS REPORTER