RU2492697C1 - Method for moisture-and-heat treatment of cereal crop grains using by-products of their processing in feedstuff technology - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: invention relates to grain-processing industry and may be used in lines for processing grain-products and feedstuffs production. The method involves grains steaming, moisture tempering , mixing drying and cooling. Prior to steaming one performs pre-heating. Drying is performed in a boiling layer in a closed circuit of its recirculation. After drying grains are delivered for peeling. Part of exhaust superheated steam is delivered for grains pre-heating. The by-products generated during peeling are dosed for extrusion, mixed with feedstuff components and delivered into the extruder equipped with a hating jacket. The produced extrudate is cooled, milled and fractioned into the coarse, medium and fine fractions. The coarse fraction is returned for additional milling; the medium fraction is discharged as the ready levelled coarseness extruded feedstuff while the fine fraction is delivered for extrusion with the output. The grins cooling after is performed with the help of a projector refrigerating machine including a steam generator, an ejector, an evaporator, a condensate recuperator, a thermal regulation cock, a cold receiver operating by way of a closed thermodynamic cycle.

EFFECT: invention usage will enable enhancement of drying energy efficiency due to usage of superheated stem as the heat medium.

3 tbl, 1 dwg

Description

The invention relates to the grain processing industry and can be used in lines for processing grain products and the production of animal feed.

The closest in technical essence and the achieved effect is the method of hydrothermal treatment of grain cereals [Egorov G.A. Flour technology. Cereal technology. - 4th ed., Revised. and additional tutorial. - M .: Kolos, 2005. - 296 pp.], According to which the grain, cleaned of weeds and grain impurities on the grain separator and the trier, and passed to capture ferroimpurities through magnets, is fed to the steamer and subjected to steam treatment at a pressure of 0 , 25 ... 0.30 MPa for 3 ... 5 minutes, after steaming, the grain is kept in a bunker for 30 minutes to enhance the transformation of the structural, mechanical and technological properties of grain, then it is dried, cooled and, after winnowing, sent to peeling. The moisture content of the grain is reduced to 12.5 ... 14.5%.

The disadvantages of this method are:

- low drying efficiency of grain cereals, because a significant part of the heat is released into the atmosphere with the spent drying agent, and is not used, for example, to heat grain before steaming;

- there are no conditions for the use of by-products of grain processing of cereals in feed technology;

- uneven drying;

- high energy costs due to the lack of recovery and utilization of secondary energy resources, closed recycling;

- drying grain of cereal crops with superheated steam in a vibro-boiling layer is not provided, providing high bulk properties of the grain mass when moving due to gravitational forces, uniformity of drying when removing surface and osmotically bound moisture;

- the use of by-products is not provided.

An object of the invention is to increase the energy efficiency of drying due to the use of superheated steam as a heat carrier, to reduce specific energy costs and to create an environmentally friendly, resource-saving technology for the heat and thermal treatment of cereal crops using the products of their processing in animal feed technology by organizing recirculation schemes for energy flows.

The object of the invention is achieved by the fact that in the method of thermal treatment of grain cereals using by-products of their processing in feed technology, including steaming the grain for 3 ... 5 min at a vapor pressure of 0.25 ... 0.30 MPa, thermal moisture leveling for 30 minutes, mixing, drying and cooling the grain, the new thing is that before steaming the grain, it is preheated to a temperature of 120 ... 130 ° C, and the grain is dried to a moisture content of 12 ... 14% in a fluidized bed with steam at a temperature of 120 ... 130 ° C and a speed of movement of grain of cereal crops 0.6 ... 0.8 m / s in a closed loop of its recirculation, and after drying, the grain is sent for peeling; part of the spent superheated steam in the amount of moisture evaporated from the grain is sent to preheating the grain; by-products formed during the peeling of cereal crops - husk, chop, flour, are dosed in the required amount for extrusion, mixed with the components of the feed and sent to the extruder with a heating jacket; the resulting extrudate is cooled, crushed and fractionated into coarse, medium and fine fractions, with the coarse fraction being returned to regrind, the middle fraction being withdrawn as a finished extruded compound feed of equal size, and the small fraction for extrusion with a conclusion; grain cooling after drying is carried out using a steam ejector chiller including a steam generator, an ejector, an evaporator, a condenser-recuperator, a thermostatic valve, a cold receiver operating in a closed thermodynamic cycle; the working steam obtained in the steam generator at a pressure of 0.8 ... 1.0 MPa is sent to the ejector nozzle, while creating a reduced pressure of 0.0009 ... 0.001 MPa and a temperature of 4 ... 7 ° C in the evaporator with recirculation in the refrigerant receiver, as which use water; the resulting mixture of refrigerant vapor and working steam after the ejector with a pressure of 0.25 ... 0.3 MPa is divided into three streams, one of which is directed to steaming the grain, the second into the heating jacket of the extruder, the third into the condenser-recuperator for overheating the steam supplied for drying, due to regenerative heat transfer; grain cooling after drying and cooling of the obtained extrudate is carried out with air, which is cooled in the cold receiver of the steam ejector refrigeration machine by heat transfer from the refrigerant with the formation of recirculation circuits; in this case, one part of the water condensate formed in the condenser-recuperator is fed to the evaporator to replenish the loss of water, and the other, together with the condensates formed in the heating jacket of the extruder, after pre-heating the grain and when the air is cooled in the cold receiver, is taken first to the condensate collector, and then into a steam generator with the formation of a closed cycle.

The technical result of the invention is to increase the energy efficiency of drying due to the use of superheated steam as a heat carrier, to reduce specific energy consumption and to create an environmentally friendly, resource-saving technology of moisture-thermal treatment of cereal crops using their processed products in animal feed technology by organizing recirculation schemes for energy flows

Figure 1 presents a diagram that implements the proposed method of thermal treatment of grain cereals using by-products of their processing in feed technology.

The circuit contains a grain heater 1; steamer 2; feeders 3, 4; bins for thermal moisture leveling 5; dryer 6; condenser-recuperator 7; fan for steam 8; grain cooling chamber 9; ejector 10; pumps 11, 12, 13; thermostatic valve 14; evaporator 15; cold receiver 16; condensate collector 17; steam generator 18; safety valve 19; thermal electric heating elements 20; fans for air 21, 22; silos for raw materials 23, 24; screw feeders 25, 26; weight batchers 27, 28; batch mixer 29; operational hopper 30; extruder 31; compound feed cooling chamber 32; chopper 4 33; sieving machine 34; lines of material and energy flows: 0.2 - initial grain; 0.2.1 - steamed grain; 0.2.2 - dried grain; 0.2.3 - chilled grain; 1.8 - condensate; 2.1 - working steam; 2.2 - a mixture of refrigerant vapor and working steam; 2.3 - spent superheated steam; 2.4 - superheated steam; 3.1 - cold air; 3.2 - air after cooling; 5.1 - refrigerant; 5.2 - refrigerant vapor.

The method of thermal treatment of grain cereals using by-products of their processing in the technology of animal feed is as follows.

Grain, cleaned of weed and grain impurities on a grain separator and triera, and passed to capture ferro-impurities through magnets, is sent for preheating to grain preheater 1, and then fed to steamer 2 using feeder 3 and subjected to steam treatment at a pressure of 0.25 ... 0.30 MPa for 3 ... 5 minutes. After the steamer, grain with a moisture content of 16 ... 18% is fed through feeder 4 along lines 0.2.1 to the bins for thermal moisture leveling 5, where it is kept for 30 minutes to enhance the conversion of structural, mechanical and technological properties.

Aged grain in hoppers 5 is fed to dryer 6, where it is dried to a moisture content of 12 ... 14% superheated steam in a fluidized bed with a temperature of 120 ... 130 ° C and a speed of 0.6 ... 0.8 m / s in a closed loop 2.3. At the same time, part of the spent superheated steam with a temperature of 105 ... 110 ° C in the amount of moisture evaporated from the grain is diverted to pre-heating the grain along line 2.3. The dried grain through line 0.2.2 enters the cooling chamber 9 and then through line 0.2.3 for peeling.

By-products formed during the peeling of cereal grain - husk, chop, flour, from the bins by 24 screw feeders are fed into a weighing batcher, from where they are then dosed in the required quantity into a batch mixer 29. At the same time, into the mixer 29 from the bins 23 using screw feeders 25 and a weight dispenser 27 dispense the remaining components of the feed in accordance with the recipe. After the mixer, the resulting mixture is first sent to the operational hopper 30, which further allows for a continuous supply of the mixture to the extruder 31 equipped with a heating jacket.

The extrudate is cooled in the cooling chamber of the compound feed 32, and then fed to the grinder 33 for grinding and then fractionated into a sieving machine 34. The coarse fraction extracted in the machine 34 is returned to the grinder 33 for refining, the coarse fraction is returned to the extruder 31, and the middle fraction is withdrawn as finished extruded compound feed of leveled size.

In this method, a steam ejector chiller is used, including a steam generator 18, equipped with a safety valve 19, an ejector 10, an evaporator 15, a condenser-recuperator 7, a thermostatic valve 14, a cold receiver 16 operating in a closed thermodynamic cycle.

The working steam obtained in the steam generator 18 under a pressure of 0.8 ... 1.0 MPa is sent via line 2.1 to the ejector nozzle 10, while creating a reduced pressure of 0.0009 ... 0.001 MPa and a temperature of 4 ... 7 ° C in the evaporator 15. Refrigerant , which is used as water, is recycled through line 5.1 using a pump 13 in the cold receiver 16. Vapors of the refrigerant through line 5.2 enter the ejector 10, where they are mixed with working steam. The resulting mixture after the ejector with a pressure of 0.25 ... 0.3 MPa is divided into three streams (lines 2.2), one of which is directed to steaming the grain in a steamer 2, the second in the heating jacket of the extruder 31, and the third in the condenser-recuperator 7 for overheating steam to a temperature of 120 ... 130 ° C, supplied to the drying line 2.4, through regenerative heat transfer.

The grain is cooled after drying and the extrudate is cooled with cold air, which is sent through lines 3.1 with the help of fans 21 and 22 to the cooling chambers 9 and 32, respectively. Moreover, the air is cooled in the cold receiver 16 of the steam ejector refrigeration machine by heat transfer from the refrigerant. After cooling, the air through lines 3.2 is returned to the cooler 16 with the formation of recirculation circuits.

From the condenser-recuperator 7, the condensate of the mixture of refrigerant and working steam is discharged along line 1.8 using pump 11 and divided into two parts, one of which is fed to the evaporator 15 to replenish the loss of water, and the other to the condensate collector 15. The condensate collector is also fed the condensate formed in the heating jacket of the extruder 31, the condensate after pre-heating the grain from the heater 1 and the condensate formed during cooling of the air in the cold receiver 16. From the collector 15, the water condensate through line 1.8 is sent via pump 12 to arogenerator 18 to form a closed loop.

In the case of technological and emergency failures in the operation of the steam generator associated with a possible increase in the pressure of saturated water vapor in its working volume, a safety valve 19 is provided.

The method of thermal moisture treatment of cereal grain using by-products of their processing in the feed technology is illustrated by the following example.

The method of thermal moisture treatment of buckwheat grain is implemented for a production line with a capacity of 5 t / h for the finished product in the production conditions of JSC "Hercules" in Bobrov.

Buckwheat grains are cleaned of weed and grain impurities on an air-sieve separator when sorting sieves with Δ7 mm triangular holes are installed to isolate large impurities and seed sieves with 2.4 × 20 mm rectangular openings to isolate small impurities. Small and large impurities are controlled in screening when installing the same sieves. Next, the grain is screened in aspirators and sent to a trie-oats picker to isolate grains of wheat and other elongated weed seeds. Purified buckwheat grain after passing through magnets to capture impurities is sent for preheating to a temperature of 40 ° C in a grain heater. During pre-heating, surface and osmotically bonded moisture is removed from the grain, uniform convective heat and mass transfer between air and grain is ensured, the bulk properties of the grain mass during gravitational movement of grain are increased due to overcoming the adhesion forces between individual grains.

Preheated grain is fed to a steamer, in which it is subjected to steam treatment at a pressure of 0.27 MPa for 5 minutes. After the steamer, the grain with a moisture content of 18% is kept for 30 minutes in the bins for thermal moisture equalization to enhance the conversion of structural, mechanical and technological properties.

Buckwheat grain aged in bins is dried to a moisture content of 12.5% in a fluidized bed dryer with superheated steam with a temperature of 125 ° C and a speed of 0.8 m / s in a closed loop. At the same time, part of the spent superheated steam with a temperature of 110 ° C in the amount of moisture evaporated from the grain is diverted to preheating the grain. The dried grain is fed to cooling to a temperature not exceeding the air temperature of the production room by ± 5 ° C. As a result of heat and heat treatment, the fruit shells of buckwheat grains become more elastic, and the kernel is more durable, which facilitates subsequent peeling of the grain and provides an increase in the yield of whole cereals.

By-products (husk, chop, flour) formed during peeling of buckwheat grain are dosed in a weight batcher, and in an amount of not more than 5%, they are fed to a batch mixer, into which the rest of the compound feed is dosed at the same time in accordance with the recipe. The resulting mixture is sent to the operational hopper, which allows for continuous supply of the mixture to an extruder equipped with a heating jacket. The resulting extrudate is cooled in the cooling chamber of the feed, and then fed to the grinder for grinding. Next, fractionation is carried out in a sieving machine into coarse, medium and fine fractions: the coarse fraction is returned for regrinding into the grinder, the fine fraction is returned to the extruder, and the middle fraction is withdrawn as a finished extruded compound feed of equal size.

A steam ejector chiller operating in a closed thermodynamic cycle is used, including a steam generator, an ejector, an evaporator, a condenser-recuperator, a thermostatic valve and a cold receiver ..

The working steam obtained in the steam generator under a pressure of 0.9 MPa is sent via line 2.1 to the ejector nozzle, while creating a reduced pressure of 0.0009 MPa and a temperature of 6 ° C in the evaporator. The refrigerant (water) is recirculated in the refrigerator with a pump. Refrigerant vapor enters the ejector and mixes with the working vapor. The resulting mixture after the ejector with a pressure of 0.25 MPa is divided into three streams, sent to the grain for steaming in a steamer, in the heating jacket of the extruder and in a condenser-recuperator for superheating steam to a temperature of 125 ° C, supplied to drying by means of regenerative heat transfer.

The grain is cooled after drying and the extrudate is cooled with cold air. The air is cooled in the cold receiver of the steam ejector chiller by heat transfer from the refrigerant. After cooling, the air is returned to the cooler with the formation of recirculation circuits.

The condensate of the mixture of refrigerant and working steam is removed from the condenser-recuperator and divided into two parts, one part is fed to the evaporator to replenish the loss of water, and the other is sent to the condensate collector, which also contains the condensate formed in the heating jacket of the extruder, after preheating grain from the heater and formed during cooling of the air in the refrigerator. Water condensate from the condensate collector is sent to the steam generator with the formation of a closed cycle.

Technical characteristics of the steam-ejector chiller used in the feed production line with a capacity of 5 t / h for the finished product:

cooling capacity, kW thirty boiling temperature: in the evaporator, ° С four in a steam generator, ° С 170 condensation temperature, ° С 127 inlet fat temperature to condenser, ° С twenty ejection coefficient 0.4 heat transfer coefficient, · W / m ² K 12 cooling area evaporator surface, m ² 180 refrigerant water

The proposed method of thermal moisture treatment of buckwheat grain allows you to create conditions for the implementation of energy-efficient technologies in continuous operation of the main and auxiliary equipment.

Additional technological methods make it possible to implement the proposed method as an energy-saving and environmentally friendly technology, in particular, to provide air cooling using a heat pump unit in a closed circuit for its recirculation and to reduce oxidation of the product with atmospheric oxygen (technological task), and to eliminate the emission of a dust fraction with exhaust air in atmosphere (ecological task), use the recovery of the heat of condensation of the refrigerant in the condenser of the heat pump unit To heat the air (power problem). The proposed method solves the complex problem of rational energy supply of new technological operations, through which the effect on the grain is carried out, which is of particular relevance to the use of the method in small enterprises, farms, mini-workshops and makes the method more attractive for specialists in the grain processing industry.

Table 1 presents the quality indicators of buckwheat grain during hydrothermal treatment by known and proposed methods before peeling.

Table 1 Indicators Way Famous Proposed Humidity% 14.5 14.0 The core content,% 71.0 72.0 Weed impurity,% 2.0 2.0 Spoiled grains,% 0.3 0.2 Grain admixture, %, 3.0 2.0 including: collapsed grains 2.0 1,5 Sprouted grains 1,0 0.7 Pest infestation absent absent

The yield of buckwheat kernel from buckwheat grain (Table 2), which underwent hydrothermal treatment (TRP) according to the proposed method, is 1.0% higher, and buckwheat is lower than with traditional moisture and heat treatment, which indicates the advantage of this method.

table 2 Processing products, yield,% Way Famous Proposed Buckwheat groats 62.0 63.0 Buckwheat groats 5,0 4.0 Feed pellet 3,5 3.0 Category I and II waste 6.5 6.5 Category III waste, mechanical losses 0.7 0.7 Husk 20.8 21.3 Shrinkage 1,5 1,5 Total one hundred one hundred

Table 3 presents the results of comparing the quality indicators of buckwheat produced from steamed buckwheat grain.

Table 3 Quality indicators Way Famous Proposed Color Brown different shades Brown plain Smell Intrinsic, without outsiders Intrinsic, without strangers Taste Intrinsic, no off-flavors Intrinsic, without outsiders Humidity% 14.0 14.0 Benign core,%, 97.5 98.2 including chopped kernels 5,0 3,5 Unsweetened grains,% 0.5 0.4 Weed impurity,% 0.55 0.4 Muchka,% - - Corrupted kernels,% 0.2 0.1 Digestibility, min 25 22 Pest Control - - Metallomagnetic impurity, mg / kg 3.0 3.0 Mold fungi, cells in 1 g are absent are absent E. coli bacteria, 1 g are absent are absent

As can be seen from table 1-3, as a result of a deeper moisture-thermal treatment according to the proposed method, adhesives in the fruit shells of grain are destroyed, starch gelatinization occurs in the peripheral layers of the endosperm. Moisture and heat treatment inactivates enzymes, including lipase and lipoxygenase, while improving the consumer advantages of cereals, as well as storage stability. The color of cereals improves: grains of cereal crops have a uniform brown color due to a more uniform reaction of melanoidin formation. The output of a benign kernel from cereal grains according to the proposed method of moisture and heat treatment is 0.7% higher, and the content of chopped kernels is 1.5% lower than in cereals that underwent traditional hydrothermal treatment.

Deviation of temperature and hydrodynamic conditions during pre-heating of grain with air and subsequent drying with superheated steam from the specified values leads to inevitable heat and energy losses and deterioration of the quality of the finished product.

The proposed method of thermal moisture treatment of cereal grain using by-products of their processing in the feed technology allows you to:

- increase the efficiency of the drying process;

- to stabilize the temperature regime of moisture and heat treatment of grain cereals in the field of preset values, which allows to provide the necessary structural and mechanical parameters of the product before peeling;

- reduce energy consumption per ton of dried and chilled grain by 10 ... 15%;

- to provide environmentally friendly technology for the thermal and thermal treatment of grain cereals, since energy flows are carried out in closed recirculation circuits;

- use by-products in the production of animal feed.

Claims (1)

A method for the thermal and thermal treatment of cereal crops using by-products of their processing in animal feed technology, including steaming the grain for 3 ... 5 minutes at a steam pressure of 0.25 ... 0.30 MPa, thermal and moisture leveling for 30 minutes, mixing, drying and cooling the grain, characterized in that before steaming the grain, it is preheated to a temperature of 120 ... 130 ° C, and grain drying to a moisture content of 12 ... 14% is carried out in a fluidized bed with superheated steam with a temperature of 120 ... 130 ° C and the speed of movement of grain cereals round 0.6 ... 0.8 m / s in a closed loop recycling it, and after drying the corn is sent to peeling; part of the spent superheated steam in the amount of moisture evaporated from the grain is sent to preheating the grain; by-products formed during the peeling of cereal crops - husk, chop, flour, are dosed in the required amount for extrusion, mixed with the components of the feed and sent to the extruder with a heating jacket; the resulting extrudate is cooled, crushed and fractionated into coarse, medium and fine fractions, with the coarse fraction being returned to regrind, the middle fraction being withdrawn as a finished extruded compound feed of equal size, and the small fraction for extrusion with a conclusion; grain cooling after drying is carried out using a steam ejector chiller including a steam generator, an ejector, an evaporator, a condenser-recuperator, a thermostatic valve, a cold receiver operating in a closed thermodynamic cycle; the working steam obtained in the steam generator at a pressure of 0.8 ... 1.0 MPa is sent to the ejector nozzle, while creating a reduced pressure of 0.0009 ... 0.001 MPa and a temperature of 4 ... 7 ° C in the evaporator with recirculation in the refrigerant receiver, as which use water; the resulting mixture of refrigerant vapor and working steam after the ejector with a pressure of 0.25 ... 0.3 MPa is divided into three streams, one of which is directed to steaming the grain, the second into the heating jacket of the extruder, the third into the condenser-recuperator for overheating the steam supplied for drying, due to regenerative heat transfer; grain cooling after drying and cooling of the obtained extrudate is carried out with air, which is cooled in the cold receiver of the steam ejector refrigeration machine by heat transfer from the refrigerant with the formation of recirculation circuits; in this case, one part of the water condensate formed in the condenser-recuperator is fed to the evaporator to replenish the loss of water, and the other, together with the condensates formed in the heating jacket of the extruder, after pre-heating the grain and when the air is cooled in the cold receiver, is taken first to the condensate collector, and then into a steam generator with the formation of a closed cycle.