LV15005B - Method for the production of xyloze - Google Patents

Abstract

The invention relates to industrial methods for the production of xylose from plant biomass containing xylan and can be used in the production of xylose from hardwood, straw, corncobs and other types of plant biomass containing xylan. The plant biomass is ground to sizes of technological chips, mixed with a sulphuric acid solution and treated with steam at elevated temperature. Xylose is extracted from the plant biomass treated thereby.

Description

The invention relates to the industrial production of xylose from plant biomass containing xylan. The invention can be used for the complex processing of hardwood, straw, corn cobs, and other plant biomass containing xylan.

There is a known method for obtaining xylose from plant biomass, wherein the xylan content is from 10% to 35% based on dry biomass. Following this process, the plant biomass containing xylan is hydrolyzed by treatment with an aqueous solution containing sulfur dioxide in a concentration of 0.1 to 2.5% at 100 to 180 ° C for 0.1 to 2.0 hours. By this method, the yield of xylose is 30-80% based on the theoretically possible amount of xylan in the plant biomass. (European Patent EP20090821646, published May 2011)

August 3).

The disadvantages of this technique are:

- treatment of xylan-containing plant biomass with an aqueous solution containing 2.5% of the catalyst, which results in the need for large amounts of water and catalyst, which worsen the economics and ecology of the process;

- use of high temperatures (up to 180 ° C) for the processing of plant biomass containing xylan;

- long process time (up to 2 hours).

The main object of the invention is to greatly reduce the amount of aqueous solution required, which will enable the economic and environmental performance of the process to be improved. Other objects of the invention are: to reduce the temperature and the duration of the process by treating plant biomass containing xylan.

The set objectives are achieved by treating xylan-containing plant biomass not with an aqueous solution containing the catalyst as in the prototype and other known techniques, but with water vapor in the presence of a small amount of catalyst. In addition, the temperature and the processing time of plant biomass containing xylan decreased simultaneously.

The treatment of xylan-containing plant biomass with water vapor in the presence of a small amount of catalyst, not with a catalyst-containing aqueous solution, is the main difference between the proposed process and the other known xylose-producing plant biomasses. In addition, the proposed technique is an excellent technical solution to the problem under investigation, since it is not possible to find such a solution based on known regularities.

The proposed technical solution is not known from the scientific and technical literature, which proves its novelty.

The practicality of the proposed process is demonstrated by the fact that the plant biomass is not treated with a catalyst-containing aqueous solution, as in the prototype, but with water vapor in the presence of a small amount of catalyst, up to 30% by weight of dry feedstock. This allows a 5-fold reduction in the amount of reaction solution required compared to the prototype and other known xylose production techniques. This, of course, greatly improves the economics and ecology of xylose extraction from plant biomass containing xylan.

Based on the above, it can be concluded that the proposed process for xylose extraction from xylan-containing plant biomass differs significantly from the prototype and other known techniques. It is characterized by an excellent technical solution as well as by its novelty and ability to be used in industrial practice. Therefore, the proposed method has all the features necessary for the invention.

The proposed method is applied in the following way: the xylan-containing plant biomass, such as birch wood, is milled to the size of a technological chip and mixed with a sulfuric acid solution in a concentration of 10-20% and not more than 30% by weight of dry birch wood. Birch wood chips, mixed with a sulfuric acid solution, are charged to a 3.8 L reactor and treated for 10-20 minutes with water vapor at 120-140 ° C. After such treatment, the resulting xylose is extracted from the birch chips. The yield of xylose is up to 17.9% based on the dry weight of birch wood, or 84.5% of the theoretically possible amount.

1. Example

700 g birch wood chips with a moisture content of 15.2% are mixed with 60 g sulfuric acid solution at 20% concentration and 10% sulfuric acid solution based on dry birchwood pulp. Loading the resulting material

-3 reactor, 3.8 L, and treated with steam at 120 ° C for 20 min. This type of treated birch wood chips is extracted with water at 120 ° C for 60 min. 62.4 g of xylose are obtained, which is 10.5% on the basis of the birch dry weight or 49.5% of the theoretical yield.

2. Example

700 g birch wood chips with a moisture content of 15.2% are mixed with 100 g sulfuric acid at a concentration of 15% and a sulfuric acid solution of 17% on the dry weight of the birch wood. The resulting material is charged to a 3.8 L reactor and treated with water vapor at 130 ° C for 15 min. This type of treated birch wood chips is extracted with water at 120 ° C for 60 min. 85.1 g of xylose are obtained, which is 14.3% on the basis of the birch dry weight, or 67.4% on a theoretical basis.

Example 3

700 g birch wood chips with a moisture content of 15.2% are mixed with 180 g sulfuric acid at a concentration of 10% and 30% sulfuric acid based on the dry weight of the birch wood. The resulting material is charged to a 3.8 L reactor and treated with water vapor at 140 ° C for 10 min. This type of treated birch wood chips is extracted with water at 120 ° C for 60 min. 106.3 g of xylose are obtained, which is 17.9% on the basis of the birch dry weight, or 84.5% of theory.

Claims (1)

Claims A process for obtaining xylose from a plant biomass containing at least 10% xylan by hydrolyzing it in the presence of a catalyst to xylose and isolating the target product, characterized in that the plant biomass containing xylan is mixed with a sulfuric acid solution at a concentration of 10-20% and not more than 30% of dry vegetable biomass, treat the resulting mixture with water vapor at 120-140 ° C and extract xylose from the treated biomass.