Glossary
Steel and refining
Claus unit and sulphur recovery unit
Also known as SRU, Claus unit, Claus process, sulphur recovery.
A Claus unit — also called a sulphur recovery unit (SRU) — recovers elemental sulphur from H₂S-bearing acid gas in a refinery or gas-processing plant. The Claus process partially combusts H₂S to SO₂, then catalytically reacts the remainder of the H₂S with SO₂ to form liquid sulphur in two or three downstream converter stages.
Cleaning targets
- Waste-heat boiler (WHB) downstream of the Claus reaction furnace — high-temperature economiser surfaces foul with ammonium-salt and sulphur deposits
- Sulphur condenser tubes — periodic external cleaning during outages
- Acid-gas line dust traps — particulate from upstream
Sonic-horn duty
Sonic horns on the SRU waste-heat boiler economiser keep ammonium-salt and sulphur deposits from consolidating between scheduled maintenance windows. The high-value, continuous-operation nature of SRUs makes the avoidance of unplanned shutdowns particularly valuable.
Related terms
Related terms
- Reformer furnaceA reformer furnace produces hydrogen by reacting natural gas with steam over a nickel catalyst at high temperature. Convection-section ammonium-salt fouling is the principal cleaning concern.
- Waste-heat boilerA waste-heat boiler recovers heat from a process gas stream — Claus SRU exhaust, BOF off-gas, sulphuric-acid converter — to generate steam. Fouling pattern depends on the source process.
- Sonic hornA sonic horn is a pneumatically-driven low-frequency sound emitter (typically 60–400 Hz at 140–180 dB SPL) used to dislodge particulate fouling from boilers, ESPs, baghouses and process vessels.