Production of cellulose pulp bleaching chemicals
CA 2098062 A1 · Owner: Suokas, Jaana · Inventors: Henricson, Kaj; Suokas, Jaana
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Hydrogen peroxide for cellulose pulp bleaching is produced directly at a pulp mill without electrolysis. Hydrogen is produced from black liquor from the pulp mill pulping process, and that hydrogen is then reacted (e.g. with oxygen and anthraquinone) to produce hydrogen peroxide, which is in turn used to bleach pulp in a P stage directly on site. The hydrogen is produced from the black liquor by heat treatment to produce an off-gas containing DMS, and other hydrocarbons. Hydrogen can be produced from the off gas in a number of ways, including by reacting it with a melt in a recovery boiler or ash from a, recovery boiler.
Read the whole patent
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 June 9, 1993. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended June 9, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 9, 2015.
- 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.