Pulp and paper
Total Reduced Sulphur
Also known as TRS, total reduced sulfur.
Total Reduced Sulphur (TRS) is the aggregate emissions metric that adds up the reduced-sulphur compounds released from kraft pulping — hydrogen sulphide (H₂S), methyl mercaptan (CH₃SH), dimethyl sulphide ((CH₃)₂S) and dimethyl disulphide ((CH₃)₂S₂). TRS is the signature emissions-and-odour metric regulated for kraft mills under most jurisdictions' permit conditions.
Sources of TRS
- Recovery boiler flue gas (during upsets or poor combustion)
- Lime kiln flue gas
- Brown stock washers and diffusers
- Black-liquor evaporators
- Smelt-dissolving-tank vent
Cleaning relevance
TRS is fundamentally a combustion-control and operating-discipline problem, not a cleaning problem. However, well-cleaned recovery boilers and lime kilns operate more stably and produce lower TRS excursions during transient operation. Continuous sonic-horn cleaning indirectly supports TRS compliance by preserving stable boiler operation.
Related terms
Related terms
- Recovery boilerA recovery boiler burns kraft black liquor to generate steam, electrical power and recovered pulping chemicals. Iconic application for sonic horns on superheater cleaning.
- Lime kilnA lime kiln calcines spent lime mud back to burnt lime (CaO) for re-use in the kraft pulping chemical recovery cycle. Preheater chain section fouling is a recurring operational issue.