US EPA

1134308 

Journal Article 

Investigating the source of high TRS emissions from a dissolving tank vent 

Sidebottom, J; Moffat, W 

2008 

Yes 

Appita Journal
ISSN: 1038-6807 

61 

6 

472-478 

The source of total reduced sulfur (TRS) compounds in a recovery boiler dissolving tank vent stack was investigated. Emission tests were carried out with weak wash as the scrubbing medium in the dissolving tank vent scrubber, as well as the dissolving agent in the dissolving tank itself. The tests were repeated with water replacing weak wash. Methyl mercaptan (MeSH) emissions disappeared when water was used, indicating that the weak wash itself was the main source of MeSH emissions in the dissolving tank. Most of the MeSH was found to be generated in the scrubber itself, since the concentration of MeSH after the scrubber was consistently higher than that before the scrubber. The exact mechanism by which this happens remains unknown, but there is a possibility that as the weak wash is sprayed through high pressure nozzles into the scrubber, it could be atomised, releasing low boiling point organic compounds as gaseous emissions. Condensate from the evaporators and the stripper is used to produce weak wash in the lime mud washer. The quality of this condensate is therefore important to ensure good quality weak wash. A proposal has now been put forward to implement condensate segregation by creating condensate streams with different concentrations of impurities such as sulfur, turpentine and methanol. The low concentration condensate would then be used to generate weak wash for emission scrubbing, thereby eliminating the emissions at the source. 

Boilers; Air pollution control; mud; Pollution control equipment; Streams; Emissions; Sulfur; Scrubbers; Lime