Title:
METHOD FOR PRODUCING CELLULOSE
Document Type and Number:
WIPO Patent Application WO/2000/050689
Kind Code:
A1
Abstract:
The present invention relates to a method for producing kraft cellulose that involves preparing a highly-selective polysulphide alkali liquor by oxidising a white alkali liquor in a new heterogeneous catalyst A, B or C. The wood is then cooked in the alkali liquor thus obtained and the cellulose is separated, rinsed and submitted to a delignification process using a polysulphide alkali liquor until a Kappa number of 3 to 8 is reached. The method further involves a chlorine-free bleaching process, regenerating the alkali liquor and steam-stripping the volatile sulphide compounds TRS (hydrogen sulphide, methylmercaptan, dimethylsulphide, dimethyldisulphide) and the $g(a)-pinene before oxidising them in condensates, gases and gaseous effluents in a heterogeneous catalyst (D, C) until water-soluble, non-toxic and non-volatile sulphates (Na¿2?SO¿4?), thiosulphates (Na¿2?S¿2?O¿3?) and sulphonates are obtained. The method further involves supplying the purified condensates towards the caustic soda or cellulose rinsing. This method increases the yield of quality cellulose by 3 to 10 %, reduces the generation of volatile sulphide compounds and $g(a)-pinene by 60 to 80 % during the cooking process, reduces more than ten times the energy consumption for eliminating the TRS and the $g(a)-pinene without discharging secondary waste such as SO¿2?, NO¿2? and CO¿2? into the atmosphere, and also reduces the wood, water and fuel consumption.
More Like This:
| JP4663815 | Calcium carbonate manufacturing method |
| WO/1993/004231 | PROCESS FOR GAS PHASE DELIGNIFYING WOOD PULP |
| JPS53130304 | PULP MAKING METHOD |
Inventors:
GOROKHOV ALEXANDR (CA)
YEREMEYEVA IRINA (CA)
YEREMEYEVA IRINA (CA)
Application Number:
PCT/IB1999/000388
Publication Date:
August 31, 2000
Filing Date:
February 22, 1999
Export Citation:
Assignee:
GOROKHOV ALEXANDR (CA)
YEREMEYEVA IRINA (CA)
YEREMEYEVA IRINA (CA)
International Classes:
D21C3/02; D21C11/00; D21C11/06; (IPC1-7): D21C3/02; D21C11/00; D21C11/06
Foreign References:
| CA1297212A |
Other References:
DATABASE WPI Section Ch Week 199415, Derwent World Patents Index; Class A97, AN 1994-124610, XP002126621
DATABASE WPI Section Ch Week 199432, Derwent World Patents Index; Class F09, AN 1994-261745, XP002126622
DATABASE WPI Section Ch Week 198451, Derwent World Patents Index; Class E14, AN 1984-317888, XP002126623
DATABASE WPI Section Ch Week 199432, Derwent World Patents Index; Class F09, AN 1994-261745, XP002126622
DATABASE WPI Section Ch Week 198451, Derwent World Patents Index; Class E14, AN 1984-317888, XP002126623
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