Apparatuses, methods and systems for yield increase in a kraft cooking plant
AssigneeBracell Bahia Specialty Cellulose SA
InventorsVinicius de Oliveira Salaroli, Nils Daniel Trolin
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Abstract
The present synergies for at least two parallel cooking plants, e.g., one producing dissolving pulp in a prehydrolysis kraft process, and the other producing kraft pulp by kraft pulping process, which may facilitate increased cooking yield in the kraft cooking plant producing kraft pulp by recovering the hemicelluloses solubilized in the acidic hydrolysate of the prehydrolysis kraft process. In some implementations, there may be no cold caustic extraction step on the dissolving pulp line as the target pulp purity can be achieved by performing just a prehydrolysis step, with reutilization of an acidic hydrolysate stream in a kraft pulp line.
Claims21
A process for increasing the pulp yield in a kraft cooking plant, comprising:
- utilizing a stream of acidic hydrolysate from an adjacent prehydrolysis kraft process producing dissolving wood pulp, wherein the kraft cooking plant is a parallel cooking plant producing conventional kraft pulp;
- wherein the stream of acidic hydrolysate, which contains dissolved hemicelluloses and is produced by prehydrolysis of wood chips in water phase, is reutilized in the kraft cooking plant;
- and
- wherein the wood chips in the kraft cooking plant are pretreated and impregnated with the acidic hydrolysate prior to an alkaline cooking process.
A method for producing kraft pulp, comprising:
- extracting an acidic hydrolysate from a prehydrolysis kraft process producing dissolving wood pulp, wherein the acidic hydrolysate is produced by prehydrolysis of wood chips in a water phase;
- applying the acidic hydrolysate to a parallel kraft cooking process in a kraft cooking plant for producing conventional kraft pulp, including performing an acidic impregnation of wood chips in the kraft cooking plant with the acidic hydrolysate prior to an alkaline cooking process.
Dependencies are inferred from the claim text.