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US 2014/0209261 A1Published application
Two-stage chemi-mechanical pretreatment for lignocellulosic biomass
AssigneeUniversity of New Brunswick
InventorsDennis FOUGERE, Kecheng LI
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Abstract
A process for pretreating lignocellulosic biomass that increases monomeric sugar yields in subsequent enzymatic hydrolysis and reduces specific energy consumption during production of the hydrolysable material. The pretreatment includes a chemical treatment followed by a mechanical size reduction such as a disc refining step, and includes a second chemical treatment, harsher than the first, which may precede or follow the size reduction.
Claims20
A method for treating a cellulose-containing material, the method comprising the steps of:
- (A) (a) providing a first mixture comprising the material and an aqueous first acid having a first concentration;
- and
- (b) subjecting the first mixture to a first dilute acid treatment under a first set of conditions comprising a first treatment temperature;
- (B) (a) subsequent to step (A), forming a second mixture comprising material treated in step (A) and an aqueous second acid having a second concentration;
- and
- (b) subjecting the second mixture to a second dilute acid treatment under a second set of conditions comprising a second treatment temperature,
- wherein at least one of the following conditions is met:
- (i) the second treatment temperature is greater than the first treatment temperature;
- (ii) the second concentration is greater than the first concentration;
- and
- (iii) the mixture of step (A)(a) has a consistency that is greater than the consistency of the mixture step (B)(a);
- and
- (C) subsequent to step (A), subjecting the material to mechanical size reduction.
10 more elements
A method for treating wood chips, the method comprising the steps of:
- (i) exposing a first mixture comprising the wood chips and an aqueous sulfuric acid solution, between about 1.0 and about 1.5% (w/w), at a temperature of between about 150° C. and about 180° C. for a period of time between about 15 and about 30 minutes, wherein the mixture has a consistency of between about 10 and about 25%, to at least partially hydrolyze hemicellulose of the wood chips;
- (ii) removing xylose and mannose produced in step (i) from the mixture;
- (iii) exposing a second mixture comprising the wood chips produced in step (i) and an aqueous sulfuric acid solution, between about 3.0 and about 10% (w/w), at a temperature of between about 180° C. and about 220° C., wherein the second mixture has a consistency of between about 10 and about 25%, to at least partially hydrolyze hemicellulose of the wood chips;
- and
- (iv) physically reducing the wood chips produced in step (iii) by disc refining to produce cellulosic fibers which will undergo hydrolysis to produce glucose at a yield of at least 90% in presence of 15 FPU/g glucan, and wherein net specific energy consumed in step (iii) is reduced by at least 95 percent when compared to disc refining of untreated wood chips of step (i) under the same conditions of step (iii).
2 more elements
Dependencies are inferred from the claim text.