초록 ▼

A method for produce both kraft pulp and alcohol from hardwood chips or the like. The chips are subjected to mild acid prehydrolysis following by mild caustic pre-extraction. The withdrawn hydrolysate has insufficient furfural to inhibit microorganism growth, and both the hexose and pentose sugars i

A method for produce both kraft pulp and alcohol from hardwood chips or the like. The chips are subjected to mild acid prehydrolysis following by mild caustic pre-extraction. The withdrawn hydrolysate has insufficient furfural to inhibit microorganism growth, and both the hexose and pentose sugars in the hydrolysate are fermented to ultimately produce ethanol, butanol, or the like. The chips - after caustic pre-extraction - are subjected to a sulphate cook, and wash, and the resultant pulp is kraft pulp and even has viscosity and tear strength characteristics more desirable than that of conventional kraft pulp. The pulp can be subjected to oxygen delignification, and achieve a higher K number in fewer subsequent bleaching stages than conventional kraft pulp.

대표청구항 ▼

A method of producing carbohydrate material and kraft pulp from a liquid slurry of comminuted cellulosic fiber material comprising the steps of continuously: (a) subjecting the liquid slurry of comminuted cellulosic fiber material to mild acid prehydrolysis, by subjecting said material to an acid co

A method of producing carbohydrate material and kraft pulp from a liquid slurry of comminuted cellulosic fiber material comprising the steps of continuously: (a) subjecting the liquid slurry of comminuted cellulosic fiber material to mild acid prehydrolysis, by subjecting said material to an acid concentration of, or equivalent to, about 0.2-0.5 percent H2SO4, and a temperature of about 120°C. or less; (b) subjecting the slurry of prehydrolized comminuted cellulosic fiber material to mild caustic pre-extraction, by subjecting said material to a caustic concentration of, or equivalent to, about 0.5-4.0 percent NaOH, and at a temperature of about 60°-90°C.; (c) removing hydrolysate, having carbohydrate material, released during the practice of steps (a) and (b) from the comminuted cellulosic material while continuously practicing steps (a) and (b); and (d) effecting kraft cooking of the prehydrolized, pre-extracted comminuted cellulosic fiber material to produce kraft pulp.