Sulfur Recovery

Sulfur Recovery


Sulfur recovery is an important step in many refining and natural gas processes. Many regulations require sulfur to be recovered before tail gas is flared to reduce the amount of sulfur polluted into the atmosphere. The recovered sulfur can be used for an array of different purposes including fertilizer additives or in the production of sulfuric acid.

Claus Process

In the Claus process, sulfur is recovered from H2S in Sulfur Recovery Units (SRU) and can be used for an array of purposes including fertilizer additives. Hengye offers multiple variations in its branded SulCat Series of Claus catalysts to suit the needs of our users, depending on environmental requirements and feed composition. Alumina SulCat can be used for recovery of sulfur from H2S. Promoted SulCat, Blended SulCat, or Super SulCat can be used to recover sulfur from H2S while also converting COS and CS2 into H2S to further remove the presence of sulfur from the stream.

How it Works


Hengye Inc. manufactures a variety of products in its SulCat Series for use as Claus catalysts in sulfur recovery units. The Claus Process requires catalysts with specific properties to allow the recovery of sulfur from hydrogen sulfide (H2S).
Surface Area Hengye’s specialized Claus catalysts offer a highly active surface area, which allows H2S and oxygen (O2) to be converted to water and sulfur at efficient speed and conversion rates.
Physical Durability These products are strong enough to survive the rigors of the Sulfur Recovery Unit (SRU) furnace, while maintaining working ability to offer a long lifespan.
Particle Size Distribution A tightly controlled particle size distribution ensures excellent fluid dynamic flow properties in the SRU.


Alumina SulCat, Activated Alumina Claus Catalyst
Promoted SulCat, Promoted Claus Catalyst
Blended SulCat, Blended Claus Catalyst
Super SulCat, Titania Claus Catalyst

Tail Gas Units

Tail gas can be handled in many different ways, in some cases, it is sent to flare and any remaining sulfur compounds are incinerated. In other cases that require further processing due to environmental requirements, a Tail Gas Unit (TGU) is used to convert residual COS, CS2, and SO2 found in tail gas into H2S, which is then recycled to sulfur recovery units to be processed again.

How it Works

Tail gas units reduces the amount of residual sulfurs to help meet environmental regulation. The tail gas from each reactor in the Claus process is mixed together, heated, and then hydrogen is added in the presence of a specialized catalyst, Hydro SulCat, to hydrogenate the sulfur and form H2S. After the hydrogenation reaction has taken place, the effluent is cooled and water vapor is removed, concentrating H2S in vapor phase. The water from the quench column can sent to a sour water stripper or recycled in an upgrader. The hydrogen sulfide and hydrogen that did not react is introduced into a lean amine solution, which produces a sweet gas that can be incinerated in the stack. A special regenerator will use stripping steam to regenerate the rich amine solution, which releases H2S that is then mixed with other hydrogen sulfide isolated in the tail gas unit and recycled as feed gas, back to the Claus Units to undergo the process another time.


Hydro SulCat, Tail Gas Hydrogenation Sulfur Catalyst

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