Method of inhibiting scaling in black liquor evaporators
CA 2229973 C · Owner: Kiiskila, Erkki · Inventors: Eneberg, Henrik; Kaila, Jarmo; Kiiskila, Erkki
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention relates to a method of inhibiting calcium carbonate scaling in a multi-stage evaporation plant of black liquor by heat-treating calcium- containing liquor. The method comprises the following stages: a) the calcium-containing liquor is heated to about 110 - 145 °C with direct contact with a heating medium;, b) the liquor is maintained at this temperature in a retention tank for 1 - 20 minutes to reduce the amount of calcium in the liquor by precipitating calcium carbonate; and, c) the heat-treated liquor is evaporated for combustion.
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed February 18, 1998 and granted August 13, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 18, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 18, 2020.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.