FSC 432
Petroleum Processing

Sulfur Recovery


Sulfur Recovery

As indicated in Figure 10.3, the objective of the sulfur recovery process is to convert H2S to elemental sulfur. Sulfur recovery takes place in a series of two steps: Claus Process and SCOT Process [3]. In the Modified Claus Process, partial combustion of H2S takes place to generate SO2 that is reacted with the remaining H2S to recover sulfur as elemental sulfur. The Modified Claus Process, once-through burner operation, works only with acid gases that contain more than 50% H2S by volume. In the process, hydrogen in H2S is converted to H2O. The second stage, the SCOT Process, functions as a tail gas clean-up operation to remove the sulfur compounds produced in the side reactions of the Claus Process, i.e., carbonyl sulfide (COS) and carbon disulfide (CS2).

Sulfur recovery process detailed, as described in above paragraph.
Figure 10.3. Sulfur recovery processes.
Click here for a text alternative to the figure above

Sulfur Recovery Process

Objective: to convert H2S to elemental S

First stage: Modified Clause Process

-partial combustion of H2S

-primary S recovery

-works for acid gas with >50% H2S

Second Stage: SCOT Process – Claus tail gas clean-up

-removes COS and CS2 produced by side reactions in the Clause Process

-reduces COS and CS2 to H2S

Credit: Dr. Semih Eser © Penn State is licensed under CC BY-NC-SA 4.0

[3] Petroleum Refining, by J. H. Gary, G. E. Handwerk, M. J. Kaiser, 5th Edition, CRC Press NY, 2007, Chapter 13, Supporting Processes, pp. 283-290.