Sulfur Recovery Units (Claus Plant) — Asbestos Exposure Crosswalk
What This Equipment Is
A sulfur recovery unit (SRU) — sometimes called a Claus plant — recovers elemental sulfur from hydrogen-sulfide-rich acid gas streams produced by amine units treating refinery process streams. The reaction sequence partially oxidizes H₂S in a reaction furnace, then catalytically converts the remainder over several converter beds with condensers between stages. Liquid sulfur is collected in a heated sulfur pit and shipped out as a refinery byproduct.
A typical refinery operates one or more SRU trains with associated tail-gas treatment units (TGTU) downstream. The reaction furnace runs hot (~2,000°F), the condensers run at carefully controlled temperature, and the sulfur pit is steam-traced to keep recovered sulfur in liquid form.
Asbestos Products Historically Used Around SRUs
| Product Category | Where on the SRU | Notes |
|---|---|---|
| Refractory brick / castable | Reaction furnace, waste-heat boiler transitions | See Refractory Brick, Refractory Mortar |
| Block insulation | Converters, condensers, reheaters | Calcium silicate, magnesia |
| Pipe covering | Acid gas, sulfur process gas, steam, sulfur transfer | Magnesia, calcium silicate |
| Steam-tracing insulation | Sulfur transfer lines | Specialty steam-traced insulation |
| Gaskets | All flanged connections | Asbestos sheet, spiral-wound |
| Valve packing | Process and isolation valves | Braided asbestos rope packing |
| Sulfur-pit cover insulation | Heated sulfur storage | Block insulation, asbestos cloth covers |
Why SRU Work Was a High-Exposure Activity
SRU turnarounds tear into reaction-furnace refractory, condenser tube bundles, and converter catalyst beds. The high-temperature service combined with corrosive sulfur compounds creates ongoing maintenance demand even between turnarounds. Sulfur-pit work — both routine sampling and emergency cleanout of solidified sulfur — disturbs insulation around hot equipment with limited ventilation.
Manufacturers Named in Litigation Involving SRU Components
- Foster Wheeler — SRU licensor and equipment
- Worley / WorleyParsons — SRU engineering
- Black & Veatch — SRU engineering
- A.P. Green Refractories — reaction-furnace refractory
- Harbison-Walker Refractories — refractory
- North American Refractories (NARCO) — refractory
- Johns-Manville — insulation, pipe covering
- Owens-Corning / Fibreboard — insulation
- Garlock Sealing Technologies — gaskets
Documented Product References
Images sourced from publicly available product-identification reference materials. Inclusion does not constitute a finding of liability against any company.
Trust Funds That May Apply
- A.P. Green Industries Asbestos PI Settlement Trust
- Harbison-Walker Refractories / RHI Asbestos PI Trust
- North American Refractories Company (NARCO) Asbestos PI Settlement Trust
- Manville Personal Injury Settlement Trust
- Owens-Corning / Fibreboard Asbestos PI Trust
- Garlock Sealing Technologies LLC Asbestos PI Trust
Trades Most Exposed at SRU Work
Refractory masons, pipefitters, boilermakers, insulators (Heat & Frost), refinery turnaround contractors, plant operators.
Jobsites in the Network
- Every Missouri refinery running SRU trains
- See companion pages: Fired Heaters, Heat Exchangers, Cat Cracker
Compiled from publicly filed asbestos litigation, EPA / state-DNR records, and industry-publication histories. Product and company references reflect what has been alleged or documented in publicly filed litigation. This page does not constitute a finding of liability against any company. Not legal advice; consult a licensed attorney about your specific situation.