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).

Figure 10.3. Sulfur recovery processes.

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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