RU2443781C1 - Method for production of ethyl alcohol from grain raw material - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: ethyl alcohol production method envisages peeling grains to produce a peel fraction in an amount of 2-5% wt of the total weight of grains and a fraction containing endosperm, milling the fraction containing endosperm, mixing the milled fraction containing endosperm with water, its three-stage water-and-heat treatment and enzymic hydrolysis, fermentation, fermented brew distillation to produce ethyl alcohol; milling is performed according to a closed circuit scheme envisaging passing the fraction containing endosperm through a hammer crusher with subsequent straining through a 1 mm diameter cell sieve to produce the through-product and the overtail; then the through-product is directed for mixing with water while the overtail is mixed with a new portion of the fraction containing endosperm and undergoes recrushing; the process of milling and purifying is repeatedly performed till formation of 100% through-product through of the total of the initial fraction containing endosperm a 1 mm diameter cell sieve.

EFFECT: invention allows to simplify the method for production of ethyl alcohol combined with preservation of its high quality characteristics and intensify the fermentation process.

3 ex

Description

The invention relates to the alcohol industry, and in particular to a method for the production of ethyl alcohol from grain raw materials.

A known method for the production of ethyl alcohol from grain raw materials, providing for the separation of husk from grain, the preparation of husk from husked grain, fermentation of the wort in a continuous-flow way in a fermenter battery, followed by alcohol and post-alcohol stillage, adding to the last separated husk for use as a feed product, part bards before mixing with the husk are divided into two streams, one of which at the stage of water-heat treatment is mixed with grain separated from the husk, and the other is directed a fermentation step in each fermenter (RU 2127760 C1, 20/03/1999).

The disadvantages of this method are the complexity and complexity of the process, as well as the withdrawal of part of the starch from the main technological process for the production of ethanol with separated husk.

A known method for the production of ethyl alcohol from grain raw materials, which involves grinding grain, fractioning it into husks and endosperm, heat and water treatment of both fractions. The fraction containing the husk is heated to 150-160 ° C, and then cooled and hydrolyzed with a mixture of amylolytic and cytolytic enzymes, the water-heat treatment of the endosperm is carried out at 65-75 ° C, hydrolyzed with amylolytic enzymes, sterilized, then the endosperm is additionally hydrolyzed (saccharized) and fermented, and the wort obtained after the main hydrolysis of the husk is divided into two parts: solid and liquid, the latter is returned to the stage of water-heat treatment and enzymatic hydrolysis of the endosperm, and the solid is added to the post-alcohol bard and is used as a feed product (RU 2041950 C1, 08.20.1995).

The disadvantages of this method are the insufficiently high quality of alcohol due to the processing of the fraction containing the husk at high temperature with the simultaneous loss of part of the starch in this fraction, high energy costs due to the separate water-heat treatment and enzymatic hydrolysis of the grain and husk fraction, the complexity and the complexity of the process.

The closest analogue of the present invention is a method for producing ethyl alcohol from grain raw materials, comprising separating a fraction containing husk in an amount of 15 wt.% From a fraction containing endosperm, grinding the latter according to a two-stage crushing scheme, to obtain a grinding characterized by 80-85% - passing through a sieve with a diameter of 1 mm, mixing the crushed endosperm fraction with water, its heat and water treatment, enzymatic hydrolysis, fermentation, alcohol isolation from a mature mash, before separation On the fractions, an additional pretreatment of the raw material is carried out by moistening it with a solution of enzyme preparations of cytolytic action, curing at 50-55 ° C, followed by drying to a moisture content of 14-15.5%. The fraction containing the husk is removed from the technological process for the production of ethyl alcohol and used after mixing with the post-alcohol distillery stillage to obtain a feed product (RU 2162103 C1, 01.20.2001).

The disadvantages of this method are the multi-stage process, involving the installation of additional equipment, the use of significant quantities of expensive enzyme preparations of cytolytic action.

The objective of the present invention is to simplify the process, reduce the cost of ethyl alcohol by reducing the cost of enzyme preparations and reducing energy consumption by eliminating the stages of smoothing and drying the grain at the pre-treatment stage.

The technical result achieved by using the claimed technical solution is to simplify the method of producing ethanol while maintaining its high quality characteristics and the intensification of the fermentation process.

The technical result is achieved by the fact that the method of producing ethyl alcohol from grain raw materials involves the implementation of the process of peeling grain to obtain a husk fraction in an amount of 2-5 wt.% Of the total weight of the grain and the fraction containing endosperm, grinding the fraction containing endosperm, mixing the crushed fraction, containing endosperm, with water, its three-stage water-heat treatment and enzymatic hydrolysis, fermentation, distillation of mature mash to obtain ethyl alcohol, while grinding is carried out according to the scheme closed loop, providing the passage of the fraction containing the endosperm through a hammer mill, followed by sieving through a sieve with a diameter of 1 mm to obtain a passage and descent, after which the passage is directed to mixing with water, and the descent is mixed with a new portion of the fraction containing endosperm, and subjected to repeated crushing, the grinding and sieving process is carried out repeatedly until a 100% pass through a sieve with a diameter of 1 mm of the entire initial fraction containing the endosperm is obtained.

In the present invention, the percentage removal of the husk fraction is reduced in comparison with the closest analogue by 3-7.5 times. This allows for equal losses of starch with a husk fraction (up to 1.5 wt.%) To exclude the multi-stage high-cost stage of biotechnological pre-treatment of grain. At the same time, the microbiological characteristics of the raw materials, determined mainly by the surface microflora of the grain, are improved and are at the level of the closest analogue.

Replacing the traditional two-stage grinding scheme with a closed-circuit grinding scheme allows for equal energy consumption to obtain a finer uniform grinding characterized by a 100% pass through a sieve with a diameter of 1 mm against an 80-85% pass obtained according to the traditional scheme. It is well known that the processing of finer grinding in the alcohol industry leads to an increase in the availability of starch raw materials for its subsequent water-thermal and enzymatic processing, which affects the improvement of technological parameters of the wort and the possibility of reducing the duration of the fermentation process.

The stage of two-stage grain crushing involves crushing the grain on hammer crushers of the first stage, sieving to obtain a passage and descent, further crushing the descent on hammer crushers of the second stage, followed by mixing the grinding obtained in the first and second stages.

In turn, the closed-loop crushing scheme provides for only one stage of hammer crushers. The grain is crushed, then sent to the sieve through a sieve with a diameter of 1 mm to obtain a passage and a descent, the passage is used further in the technological process (mixed with water), and the descent is mixed with a new portion of the original (unmilled) grain and subjected to repeated crushing on the same crushers. The crushing and sieving process is carried out repeatedly until a 100% pass through a sieve with a diameter of 1 mm of the entire source grain is obtained. At the same time, grinding the sample, consisting of the source grain and the vanishing, further contributes to the destruction of the latter, because individual vanishing particles are impacted both with the machine body and with whole grains. Due to this, there is a deeper grinding of the descent and obtaining a finer and more uniform grinding than when using a two-stage crushing scheme.

In addition, it was unexpectedly found that when the percentage of husking is reduced from 15 wt.% To 2-5 wt.% Of the total grain mass and the use of a closed-circuit crushing scheme, the fermentation process is intensified, i.e. reduced from traditional 72 hours to 48-66 hours. This unexpected effect may be due to several factors. Firstly, with the preservation of most of the intrinsic grain enzymes concentrated in the aleurone layer, with a reduced percentage of its removal (2-5 wt.% Husk of the total grain weight), and their greater transition to the husk fraction at 15 wt.% Removal. Secondly, with the preservation of most of the grain proteins, which are potential nitrogen nutrition for yeast. It is known that the peripheral parts of the grain contain more protein than the whole kernel, and an increase in the removal rate of the husks impoverishes the raw materials from the standpoint of nitrogen nutrition. Thirdly, when using a finer and more uniform grinding, the attack by enzymes of all grain components, including proteins, is increased.

In the present invention, the separated husk fraction, in which the ballast components of the grain are concentrated, primarily fiber, as well as the entire surface microflora, is completely removed from the technological process. In the future, it can be used after briquetting as biofuel directly at the distillery.

The characteristics of the post-alcohol stillage obtained in the method of the present invention and the closest analogue are close.

The method is as follows.

The grain is peeled to obtain 2-5 wt.% Of the total grain weight of the husk fraction, which is removed from the further process, and the fraction containing endosperm. Next, the fraction containing the endosperm is ground according to a closed loop scheme to obtain a grinding characterized by 100% passage through a sieve of 1 mm diameter. For this, at the initial stage of operation of the crushing compartment, a certain amount of fraction containing the endosperm, depending on the performance of the hammer crusher, is sent to the hammer mill. Next, grinding this batch and sieving through a sieve with a diameter of 1 mm. The passage through this sieve is a fine grinding, and the exit from the sieve is a coarse fraction, which is returned, together with the next batch of the fraction containing the endosperm, to the hammer mill. Further, such a closed grinding cycle is carried out repeatedly until a 100% pass through a sieve with a diameter of 1 mm of the entire initial fraction containing the endosperm is obtained. At the same time, the obtained passage is mixed with water at a hydromodule 1: (3.5–4.0) and amylolytic enzyme diluent preparations (α-amylase) are added in the amount of 1.5–2.0 units of AS / g of conditional starch to obtain a batch . Next, the batch is subjected to a three-stage water-thermal and enzymatic treatment, including heating the batch to 50-55 ° C with holding for 30 minutes at this temperature, raising the temperature to 65-70 ° C and holding at this temperature for 1.5 hours, raising the temperature to 95-98 ° C and holding at this temperature for 1.5 hours to obtain a boiled mass. Then, the resulting boiled mass is cooled to 56-58 ° С, amylolytic saccharifying enzymes (glucoamylase) are introduced in an amount of 6.5-7.5 units of HCl / g of conventional starch of raw materials and the final enzymatic hydrolysis (saccharification) is carried out at a temperature of 56-58 ° C for 30 minutes. The resulting saccharified wort is cooled to a fold temperature, seed yeast is introduced and fermented in a continuous-flow way. The mature mash is then distilled to obtain ethyl alcohol, and the post-alcohol distillery distillery is used to obtain the feed product.

The implementation of the claimed invention is illustrated by the following examples.

Example 1. As a feedstock, wheat is used. 100 tons of wheat with a starch content of 55.5 wt.% And an initial moisture content of 14.5% are subjected to peeling, while the husk fraction is 2 wt.% Of the total weight of the grain, no more than 0.5% of the starch of the feedstock passes into it. The remaining fraction containing the endosperm is subjected to crushing according to a closed loop scheme. The resulting grinding, characterized by 100% passage through a sieve with a diameter of 1 mm, is mixed with water, the temperature of which is 50 ° C, in a ratio of 1: 3.5. Next, the amylolytic enzyme preparation of the fluidizing effect (α-amylase) in the amount of 2.0 units of AC / g of conditional starch is added to the batch and a three-stage water-heat treatment and enzymatic hydrolysis are carried out: at a temperature of 50-55 ° C for 30 minutes (1 pause), at a temperature of 65-70 ° C for 1.5 hours (2 pause), at a temperature of 95-98 ° C for 1.5 hours (3 pause). Then, the resulting boiled mass is cooled to 56-58 ° C, a saccharifying enzyme preparation (glucoamylase) is added in an amount of 7.5 units HCl / g of conditional starch, and the final enzymatic hydrolysis (saccharification) is carried out for 30 minutes. Next, the wort is cooled to a fold temperature (20-25 ° C), seed yeast is introduced and fermentation is carried out for 66 hours. The resulting mature mash is sent to distillation (rectification) to obtain ethyl alcohol. The alcohol yield is 67.2 dal / ton of conventional starch.

Example 2. As the feedstock use rye. 100 tons of rye with starchiness of 53.7 wt.% And an initial moisture content of 13.8% are subjected to peeling, while the husk fraction is 2 wt.% Of the total grain weight, not more than 1% of the starch of the feedstock passes into it. Then the process is carried out analogously to example 1. The duration of the fermentation process is 48 hours, and the yield of ethyl alcohol is 66.9 dal / ton of conventional starch.

Example 3. As the feedstock use rye. 100 tons of rye with a starch content of 53.7 wt.% And an initial moisture content of 13.8% are peeled, while the husk fraction is 5 wt.% Of the total grain weight, not more than 1.5% of the starch of the feedstock passes into it. Then the process is carried out analogously to example 1. The duration of the fermentation process is 60 hours, and the ethanol yield is 66.7 dal / ton of conventional starch.

The proposed method allows to simplify the process of producing ethyl alcohol while maintaining its high quality characteristics, reduce the cost of the final product due to the saving of expensive additional enzyme preparations and reduce energy costs, as well as to intensify the process of fermentation of the wort, thereby increasing the turnover of the fermentation department.

Claims (1)

A method of producing ethanol from grain raw materials, including peeling grain to obtain a husk fraction and a fraction containing endosperm, grinding a fraction containing endosperm, mixing the crushed endosperm fraction with water, its three-stage water-heat treatment and enzymatic hydrolysis, fermentation, distillation of mature mash with obtaining ethyl alcohol, characterized in that the husk fraction is 2-5 wt.% of the total grain weight, and the grinding of the fraction containing the endosperm is carried out according to the closed-circuit RA, involving the passage of the endosperm fraction through a hammer mill, followed by sieving through a sieve with a diameter of 1 mm to obtain a passage and a descent, after which the passage is directed to mixing with water, and the descent is mixed with a new portion of the fraction containing endosperm and subjected to re-crushing, grinding and sieving is carried out repeatedly until a 100% passage through a sieve of 1 mm diameter of the entire initial fraction containing the endosperm is obtained.