Efficient H2S removal strategy reduces end user’s treatment costs by approximately 75%
A natural gas purification system using SulfaTreat™ hydrogen sulfide removal adsorbent was designed and supplied by SLB. It delivered outlet gas with <5 ppmv of H2S per specification while significantly reducing both capex and opex compared with the alternative proposal.
A leading Indian supplier of process engineering equipment to the oil and gas industry approached SLB for an H2S removal package for an onshore gas treatment plant in western India. The end customer had requested H2S removal downstream of a glycol dehydration unit, which meant treatment of dry instead of water-saturated gas. Pipeline specifications mandated an H2S concentration <5 ppmv after treatment, and two gas purification units were required, one online and the other on standby.
SLB offers a wide range of mixed metal oxide chemistries for H2S removal. However, treating water-saturated gas with an iron oxide–based adsorbent is significantly more cost-effective than treating dry gas with a copper oxide–based product. Consequently, in addition to quoting for a system that complied with the specifications, SLB proposed an alternative design.
Relocating the H2S removal package upstream of the glycol dehydration unit would result in water-saturated feed gas and enable use of iron oxide–based SulfaTreat hydrogen sulfide removal adsorbent. This efficient product provides a long bed life and is familiar to the end user. SLB also suggested replacing the online-standby arrangement with a lead-lag configuration, which enables fully utilizing the capacity of the adsorbent. Additionally, this configuration provides the greatest operating flexibility—production can continue uninterrupted while media is replaced.
Product consumption depends only on the amount of H2S that passes through, economically matching the need for H2S removal with variations in system flow conditions. The flexibility of the treatment process enables the system to adapt to changes in operating conditions, usually without additional capital equipment or retrofitting.
This alternative proposal was accepted, and the unit has been operating efficiently since commissioning, saving the end user approximately 75% in both capex and opex.
