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:
Jul. 11, 1978
Filed:
Sep. 17, 1976
Vincent B Diebold, Cincinnati, OH (US);
Wavell F Cowan, Montreal, CA;
John K Walsh, Cincinnati, OH (US);
C P Associates Limited, Montreal, CA;
Abstract
Solvent pulping of wood chips or other fibrous plant material is effected using an aqueous solution of a lower aliphatic alcohol in a plurality of batch extraction vessels. The charge in each vessel is heated rapidly to pulping temperature by recirculation of a primary extraction liquor having a relatively high dissolved solids content, and thereafter the charge is subjected to a series of once-through extractions or washes with successively cleaner liquors, including a final extraction or wash with fresh liquor. The extraction liquor from one extraction stage in one vessel is used in another extraction stage in another vessel. Upon completion of the extraction, the liquor is drained from the vessel, the vessel is depressurized to a solvent condenser, and the remaining solvent is steam stripped from the charge and recovered. The used extraction liquor is treated in an alcohol recovery system by flash vaporization, condensation of the solvent vapors, and vacuum stripping of the residual liquor with steam. The alcohol-free extract is then treated to recover a concentrated aqueous lignin suspension and a concentrated aqueous carbohydrate solution.