(18b) Sorbent-Based Process for Organic Sulfur Removal from Natural Gas and Natural Gas Liquids

While the conventional acid gas removal systems based on amine scrubbing and caustic treatment are highly effective in removing hydrogen sulfide (H₂S) and simple mercaptans from natural gas and natural gas liquids, these technologies are not highly effective for the removal of complex organo-sulfur compounds such as complex mercaptans (e.g., isopropyl mercaptan, tert-butyl mercaptan), sulfides (dimethyl sulfide, carbonyl sulfide), thiophenes (alkyl thiophenes) and disulfides (e.g., di methyl disulfide, carbonyl disulfide or methyl ethyl disulfide).

A new sorbent-based desulfurization process is developed that can remove organic sulfur contaminants from natural gas and natural gas liquids (NGL). The desulfurization system uses a new proprietary adsorbent that can achieve a very high sulfur capacity and removal efficiency. The sorbent is regenerated by applying a mild temperature swing cycle, with low energy input resulting in a cost effective process.

The paper will provide the details of the new technology and the results of large-scale pilot experiments showing the capabilities of processing natural gas and biogas, as well as from natural gas liquids (C4+ streams). The results of several field tests at the gas processing facilities and refineries at the pilot scale suggest that the new technology can be successfully used in the treatment of a wide range of feedstocks containing different types of sulfur contaminants, with treated product meeting the sale gas/liquid product specification. The sorbent maintains its chemical activity and mechanical durability for extended cycles. High fidelity economic evaluations for stand-alone units treating NGL streams and polishers integrated with the conventional Acid Gas Removal Units (AGRUs) for natural gas treatment suggests favorable economics for the new technology.