Gas Processing

Courtesy of Shell

Tail Gas Treating: TGT

The tail gas treatment process reduces sulfur vapor and SO2 contained in the tail gas from the Claus process to H2S and absorbs it in the absorbing solution (amine), and returns it to the Claus process, thereby achieving a high rate of sulfur recovery. Shell’s SCOT process is a representative TGT process. It is composed of a section where the sulfur content is reduced to H2S, and the section where H2S is absorbed by amine. Although dependent the feed gas composition, it yields over 99.9% sulfur recovery rate in ordinary oil refining plants and over 99.2% sulfur recovery in gas or LNG plants.


  1. Chiyoda is an authorized licensor of the Shell SCOT process. Our experience in this process is overwhelmingly rich.
  2. The SCOT process is an established technology and over 300 units are operating smoothly worldwide.
  3. One of the recent technological innovations is enhancement of the hydrogenation catalyst reducing mercaptan, COS and other organosulfurs in the tail gas of the Claus process to H2S in a lower reaction temperature so as to enhance energy saving efficiency and simplify the equipment. The use of amine, which features high H2S selectivity, achieves over 99.9% sulfur recovery of sulfurs in gas and LNG plants. These are just a few examples of Chiyoda’s know-how on the design and construction of the SCOT process. We have also designed and constructed processes similar to the SCOT process based on client decisions.
  4. Exhaust gas is treated as lower than approximately 250ppmv H2S composition gas. To provide Incinerator and Fuel Gas Desulfurization facility, the design considered in the enviroment is possible.

Applicable range

SCOT process can be utilized the Tail gas which contains sulfur compound like SO2.

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