SU382597A1 - METHOD OF CONTINUOUS VEGETATION HYDROLYSIS - Google Patents

Description

one

The invention relates to the hydrolysis industry.

Basically auth. St. No. 234948 describes a method for hydrolysis of plant raw materials in a countercurrent of raw materials and a solution of hydrolyzing liquid with a concentration of 0.6-0.8% and a temperature of 188-190 ° C using forced pressing of the material.

In this case, three separate zones are formed in the apparatus.

In the lower part of the apparatus, a zone of hydrolysis of lightly hydrolysable polysaccharides is formed and the hydrolyzate is separated from the hydrolyzable material (filtration).

In the middle part, a zone of hydrolysis of hardly hydrolysable polysaccharides is formed. In the upper part there is a zone for drying lignin and its removal from the apparatus.

The density of the layer of hydrolyzable material in the apparatus is regulated by means of a subpressing device or by supplying steam to the upper part of the apparatus and creating there an excess pressure exceeding the pressure corresponding to the boiling point of the fluid in the apparatus.

The known method has a low rate of delivery of the hydrolyzate due to the dense filtering layer formed as a result of pressing the raw material, and excessively deep hydrolysis of the raw material in the filtration zone, which leads to a decrease in the yield of PB.

The purpose of the invention is to improve the hydrolysis process, namely an increase in the rate of hydrolyzate dispensing and to reduce the conditions of the hydrolysis process in the filtration zone.

To do this, in the hydrolysis zone of the lightly hydrolysable polysaccharides, an additional hydrolyzing liquid with a concentration of

0.3-0, and a temperature of 130-160 ° C with an additional selection of the hydrolyzate from the hydrolysis zone of difficultly hydrolyzed polysaccharides. The method is as follows. Through the vertical apparatus from the bottom up

miss the raw materials. The main amount of the hydrolyzing liquid solution with a concentration of 0.6-0.8% and a temperature of 188-190 ° C is dropped from top to bottom. At the same time, a hydrolyzing liquid is additionally introduced.

concentration of 0.3-0.4% and a temperature of 130-160 ° C. Moreover, an additional input of the hydrolyzing liquid is carried out from the center of the lower part of the apparatus in the direction perpendicular to the movement of the raw material.

Thus, in the apparatus, three separate zones are formed, having different technological purposes and differing in physical and chemical parameters.

In the lower part of the apparatus, where fresh raw materials are supplied, milder conditions of hydrolysis occur as a result of a decrease in the temperature of the hydrolyzing liquid when mixed with cold raw materials coming from the feeder, l as a result of the additionally lower concentration of hydrolyzing liquid coming from the center of the device (0.3 - 0.4%) and low temperature (130-160 ° C).

In this zone, hydrolysis of the lightly hydrolysable polysaccharides of the raw material takes place and the hydrolyzate is filtered (hydrolyzate separation) obtained by hydrolysis of the hydrolyzable polysaccharides.

The middle zone is the main part of the reaction space of the apparatus, where the hydrolysis of the hardly hydrolyzable polysaccharides of the raw material takes place due to the high concentration (0.6-0.8Vo) and the freshly heated temperature (188-190 ° C) of the main hydrolyzing liquid coming from above.

Additional selection of the hydrolyzate is carried out through an additional filtering device — filter beams installed in the middle part of the apparatus.

The third zone (the upper part of the apparatus) is the zone of washing the lignin and removing it from the apparatus with the aid of a discharge tool.

With the forced pressing of the raw material, its density reaches up to 400 / sgLi and higher, which reduces the rate of hydrolyzate dispensing due to the resistance of the compacted filter layer.

The use of an additional injection of hydrolyzing liquid with a temperature of 130-160 ° C and a concentration of 0.3-0.4% creates conditions for reducing the destruction of raw materials and increasing the sugar yield from easily hydrolyzed polysaccharides.

The additional withdrawal of the hydrolyzate increases the total filtration area, reduces the height of the filter bed of the hydrolyzable feedstock, and reduces the pressure drop leading to a high compaction of the hydrolyzable feedstock.

Reducing the parameters of the additionally added hydrolyzing liquid creates in the filtration zone a layer that is less hydrolyzed to raw materials, which is necessary to reduce the entrainment of finely dispersed lignin with hydrolyzate and precipitate gummy substances on the raw materials.

As tests have shown, hydrolysates that have been filtered through a layer of less hydrolyzed raw materials are characterized by high biological purity and an increased yield of yeast with high protein content.

Example. 100 kg abs. dry sawdust and chips (composition of raw materials: 18% hemicellulose, 52% of difficultly hydrolyzed polysaccharides and non-hydrolysable residue - lignin) are passed through the vertical apparatus from the bottom up. A hydrolysing liquid with a concentration of 0.68Vo and a temperature of 188 ° C in an amount of 840 liters, i.e. 70% of the total liquid required for hydrolysis, is fed against the movement of the raw material. Total hydrolysis of 100 / cg abs. dry wood with hydronic module 12 requires 1200 l of hydrolyzing liquid.

The rest of the liquid — 360 l (30Vo) with a concentration of 0.35% and a temperature of 145 ° C is introduced from the center of the lower part of the apparatus into the zone of hydrolysis of easily hydrolysable polysaccharides in the direction perpendicular to the movement of the raw material. In the middle part of the apparatus from the zone located above the zone of hydrolysis of lightly hydrolysable polysaccharides, an additional filtering device in the amount of 900 liters with a concentration of PB of 4.0% (36 kg of PB) is carried out, and in the lower part of the apparatus, the hydrolyzate is filtered the amount of 300 liters with a concentration of PB 6.0% (18 kg PB). With the introduction of additional extraction of the hydrolyzate, the sites for the selection of easily hydrolyzable and difficultly hydrolysable wood polysaccharides were changed.

So the main part of the Sugars obtained during the hydrolysis of wood is selected through an additional filter, and the rest -

g hydrolyzed lightly hydrolysable polysaccharides selected through the main filter.

The total sugar yield is 36 + + 18 54 kg RV or 54.0% of abs. dry wood.

Calculated data and laboratory tests show that when implementing the proposed method, the rate of hydrolyzate delivery is increased by 1.5 times compared with the rate of hydrolyzate delivery according to the method described in the main author. St. N ° 234948 (see table).

As can be seen from the table data, the rate of delivery of the hydrolyzate by the proposed method is 984 l / h; 1162 l / h; 1000 l / h; and according to the method described in ed. St. No. 234948, respectively, 531 l1h; 831 l / h; 675, i.e., the rate of hydrolyzate dispensing by the proposed method is more than 40-50%. Exit PB from abs. dry wood is also on offer. my way is longer by 4-5 / a.

Prevention Invention

The method of continuous hydrolysis of vegetable raw materials by ed. St. LA 234948, different in that. In order to improve the process, the hydrolysis zone of the lightly hydrolysable polysaccharides is additionally supplied with a solution of the hydrolyzing liquid with a concentration of 0.3–0.4Vo at a temperature of 130-160 ° C with an additional selection of hydrolyzate from the hydrolysis zone of hardly hydrolyzable polysaccharides.