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Pulp and paper mills have processes that either utilize toxic gases, or whose by-products are toxic. The industry, by definition, is also extremely at danger of catastrophic fires. As a result, these facilities require continuous toxic gas and flame monitoring to keep their personnel and equipment safe.
The Kraft process is used in production of paper pulp and involves the use of caustic sodium hydroxide and sodium sulfide to extract the lignin from the wood fiber in large pressure vessels called digesters. The spent pulping liquor, called black liquor, is concentrated by evaporation and burned to generate high pressure steam for the mill processes. The inorganic portion of the black liquor is then used to regenerate the sodium hydroxide and sodium sulphide needed for pulping. Various byproducts containing hydrogen sulphide and other volatile sulphur compounds are the characteristic for pulp and paper mills that use the kraft process.
Following the kraft process, pulp stock from the digesters is washed and screened and then put through the bleaching process, which whitens or brightens the pulp. Bleach chemicals used in this process are chlorine, chlorine dioxide, oxygen, with peroxide and ozone used as alternatives. Sulphur dioxide is also a by-product of the primary bleaching process.
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| Hazard |
Source |
Safety Solution |
| Hydrogen Sulphide (H2S) (toxic) |
Wood digesters, Kraft mill chemical recovery |
Millennium II,
Millennium II BASIC,
MLP-ST1200 (Electrochemical),
Gas Shield Junior or Senior
|
| Chlorine (Cl2) (toxic) |
Washing, screening, and bleaching |
Millennium II,
Millennium II BASIC,
MLP-ST1500 (Electrochemical),
Gas Shield Junior or Senior
|
| Sulfur Dioxide (SO2) (toxic) |
Bleaching |
Millennium II,
Millennium II BASIC,
MLP-ST1300 (Electrochemical),
Gas Shield Junior or Senior
|
| Ozone O3 (toxic) |
Bleaching |
Millennium II,
Millennium II BASIC,
Gas Shield Junior or Senior |
| Fire |
Wood, paper |
Phoenix IR3 (multi-spectral infrared) detector,
Smart UV/IR detector,
Smart UVS detector |
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