The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 28, 2017
Filed:
Oct. 03, 2016
Applicant:
Valmet Ab, Sundsvall, SE;
Inventors:
Mikael Lindstrom, Lidingö, SE;
Fredrik Wilgotson, Sundsvall, SE;
Assignee:
Valmet AB, Sundsvall, SE;
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
D21C 3/02 (2006.01); D21C 3/24 (2006.01); D21C 3/26 (2006.01); D21C 7/06 (2006.01);
U.S. Cl.
CPC ...
D21C 3/022 (2013.01); D21C 3/24 (2013.01); D21C 3/26 (2013.01); D21C 7/06 (2013.01);
Abstract
The method is for the preparation of kraft pulp with increased pulping yield from lignin-containing cellulosic material using polysulfide cooking liquor. In order to increase carbohydrate stabilization and hence the yield from a kraft cooking process a first impregnation stage using polysulfide cooking liquor is implemented at high alkali and polysulfide concentration and at a low temperature. Knots are added to a high-pressure conduit extending between an impregnation vessel and a digester.