Valmet Ab

Valmet Aktiebolag

Metso Paper Inc.

Lari Lammi

Petteri Kuusisto

Dario Giordano

Stefan Antonsson

Sannet Minnaar

Patrizia Ferrando

Ismo Rosengren

Marco Bernardi

Mats Nordgren

Petri Lassila

Håkan Dahllöf

Maria Wennerström

Lars Sjödin

Berdine Coetzee

Hunphrey Landman

Susanna Minnaar

Johann Wauts

Jouni Karvonen

A method for obtaining a strong hydrolysate from cellulosic material after a hydrolysis in a batch digester is disclosed. According to the invention the cellulosic material is exposed to a 2 stage hydrolysis with a first steam phase hydrolysis followed by a liquid phase hydrolysis, and wherein the steam phase is conducted such that the degree of packing of the cellulosic material results in at least a 20% up to 100% packing increase. The liquid phase hydrolysis includes adding hot and preferably acidified hydrolysis liquid and not establishing a total L/W ratio above 3.5, but sufficient to keep the cellulosic material under the level of the hydrolysis liquid.

Method for recovering concentrated hydrolysate after hydrolysis of cellulose material

It is disclosed a process to produce a bio-product starting from a ligno-cellulosic feedstock, comprising a pre-hydrolysis step of the ligno-cellulosic feedstock in one or more pre-hydrolysis vessels to produce a liquid pre-hydrolyzate comprising water and water soluble hemicellulose, followed by a multi-step hydrolysis of the water soluble hemicellulose. The hydrolysis steps are conducted in separated vessel. The liquid pre-hydrolyzate is subjected to a partial hydrolysis step in a first hydrolysis vessel, to produce a first hydrolyzate. A portion of the first hydrolyzate, comprising remnant water soluble hemicellulose, is recirculated in at least one pre-hydrolysis vessel and subjected to a second hydrolysis step. Another portion of the first hydrolyzate comprising monomeric sugars is removed and converted to the bio-product, preferably after a refining hydrolysis step. The process also produces a hemicellulose-depleted feedstock which is preferably treated to produce a cellulosic pulp. The bio-product comprises any chemical from the groups of polyols, diols, alcohols, and carboxylic acids, or lactic acid or the group consisting of ethylene glycol, propylene glycol, or a mixture thereof.

Process to produce a bio-product

The method is for producing pulp. More particularly, a displacement batch cooking process comprises recovery of a first treatment liquid by draining of the digester, preferably not using a displacement liquid. The method may preferably be used in a prehydrolysis step, wherein the recovery of the by-products is improved. In the recovery step, after the target P-factor in the prehydrolysis stage is reached, the hydrolysate is withdrawn by draining in at least one phase obtaining a strong first liquid and thereafter any residual hydrolysate may be displaced.

Method for recovering hydrolysate

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Pori, Finland

Lari Lammi