Paper making and fiber liberation – Processes of chemical liberation – recovery or purification... – Including recovery of organic by-product
Patent
1983-07-07
1986-06-10
Kratz, Peter
Paper making and fiber liberation
Processes of chemical liberation, recovery or purification...
Including recovery of organic by-product
162 37, 162 73, 162 77, D21C 320, D21C 1100
Patent
active
045941300
ABSTRACT:
High yield pulping is achieved by cooking a lignocellulosic material in a confined chamber in the absence of added oxygen at elevated temperatures up to 240.degree. C. with an initially neutral or acidic mixture of alcohol and water in volume ratio between 50:50 and virtually anhydrous alcohol cooking liquor, using a lower aliphatic alcohol namely methanol, ethanol or n-propanol, carrying in solution at least about 0.002 moles per liter of a magnesium, calcium or barium salt as a primary catalyst soluble in at least catalytic amounts in the mixture to form barium, calcium and magnesium ions. The cooking time may range from at least two (2) minutes to under three (3) hours. The process yields bright, free-fiber pulp even at residual lignin of 80 Kappa number as high as 80% of softwood and up to 75% of hardwood weight, of viscosity (TAPPI 0.5% Cu En) above 18 up to 60 centipoise. Addition of trace amounts of an acidic compound as a secondary catalyst increases the rate of delignification. Elevated pressures on the cooking solvent mixture also increases the rate of delignification.
REFERENCES:
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Chang et al., "Recovery and GC Analysis of Wood Sugars From Organosolv Saccharification of Douglas-Fir Heartwood", Sep. 76 Canad. Wood Chem. Symposium.
Chang Pei-Ching
Paszner Laszlo
Kratz Peter
McLeod Ian C.
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