New hydrogen sulphide removal process

The new core technology uses an aqueous phase proprietary catalytic process that converts H₂S into thiosulphate. By keeping the reaction entirely in solution, the process eliminates the solid waste characteristic of liquid redox or solid media systems. The approach also prevents plugging and downstream corrosion issues often encountered with triazine treatment, according to Merichem. The only required feed reagent is potash added to feed water or produced water). The aqueous effluent can be discharged into saltwater disposal systems or sent downhole with unneeded produced water. In simplified configurations, the system can treat H₂S directly in produced water, reducing hazards associated with produced water handling.

The field trial was conducted in the Delaware Basin, the westernmost component of the larger Permian Basin, with various wells and a wide range of hydrogen sulphide concentrations up to 2%. The objectives of the trial were to demonstrate the ability to remove H₂S in sustained field operations, verify the operating window and solution capacity, compare equipment performance, and treat gas with produced water from the same wells. More than 14,000 ppm H₂S was fed into a unit that had been designed to receive a maximum of 10,000 ppm in the feed. In this condition, the unit exceeded its nameplate capacity of 2 lbs of hydrogen sulphide removal per day. In all the equipment trials, the sustained removal of hydrogen sulphide was achieved. The month-long trial also included tests using produced water. The H₂S concentration, gas ratio, and water ratio were sufficient to treat all the sales gas with produced water from the same wells despite less-than-ideal produced water being used as a feed reagent.

“The industry is continually seeking to reduce both the price and complexity of removing hydrogen sulphide from gas production, especially since oil production has shifted to increasingly sour sources, higher gas ratios, and higher water ratios,” said Jeff Gomach, Senior VP, Merichem Technologies. “ECOTREAT met all its field trial objectives and provides a highly effective method for removing hydrogen sulphide to prevent equipment corrosion, ensure worker safety, meet environmental regulations, and maintain product quality for transport.”