SU1369673A3 - Method of obtaining starch - Google Patents

Abstract

The invention relates to starch production techniques. The purpose of the invention is to reduce the water consumption of the process. The method of starch production involves grinding the starch-containing raw material, isolating the starch suspension from the crushed raw material, cleaning it and then washing the starch suspension in several steps with introducing fresh water to the last step of washing with the direction of wash water from step to step in countercurrent with the washed suspension and discharging the washed starch. . The water from the stage of washing or leaching of the starch suspension is subjected to reverse osmosis to obtain an aqueous fraction containing less than 1000 ppm. protein, and this fraction is returned to the process with fresh water. 3 tab., 2 Il. i WITH

Description

with

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one

The invention relates to a process for producing starch, namely to the wet grinding of materials containing starch.

The purpose of the invention is to reduce the consumption of WATER per process.

Figure 1 shows a flow chart for starch production from maize; figure 2 - the same, from wheat flour.

The method is carried out as follows.

Starch-containing raw materials, such as corn, potatoes or wheat, are crushed, starch suspension is separated from crushed raw material, cleaned, washed starch suspension in several stages on hydrocyclones with fresh water introduced to the last stage of washing, direct washing water from step to step in countercurrent washed slurry and washed starch slurry withdrawn. The water from the stage of washing or isolating the starch slurry is subjected to reverse osmosis to form an aqueous fraction containing less than 1000 ppm. protein, and this fraction is returned to the process with fresh water.

Separation using reverse osmosis involves bringing the solution into contact through a semipermeable membrane with a pure solvent (for example, with water), and the pressure difference across the membrane is higher than the osmotic pressure of the solution. Can ic-use pressure difference ZO - 100 atm. Since the solution in this case contains both soluble and insoluble matter, it is desirable to maintain flow through the semipermeable membrane in order to prevent or delay clogging of the membrane pores. A suitable solution to this problem is to maintain a continuous cyclic fluid flow through a pipe made of a material that is used to make a semipermeable membrane, adding a solution that needs to be divided into fractions, to a compass), a first fraction through semipermeable membrane; and removing the second fraction by separating it from the circulating fluid.

five

:

5 0 0

5 0 5 0 5

The required purity of the starch solution produced as a product depends on the purpose for which it will be used, while the nitrogen content (as a measure of soluble protein) is slightly below the range of 10-1000 ppm. on a dry basis.

The proposed method provides a reduction in the amount of fresh water supplied to the soaking without reducing the quality of the starch obtained as the final product, which is achieved by introducing an additional operation, specifically, the separation of water into two fractions. However, the energy savings achieved through the application of the method are very significant.

Example 1. Conditions for reverse osmosis are determined. In each case, the 50-liter aliquots of the feed solution are divided into 25 liters of solution that has passed the membrane (first fraction) and 25 liters of concentrate (second fraction). All used membranes are manufactured by Vafilin N.V., Hardenberg, Holland.

The membrane used provides 95% retention of NaCl at 95% and passes 44 liters of pure water at 1 m / h at a pressure of 40 atm and a temperature of 14 ° C. An intermediate aqueous solution from the concentrator of intermediate products supplied from the washing stage during the implementation of the wet grinding of corn is used as the feed product. A stream of water at a temperature of 17 ° C and at a pressure of 40 atm circulates in the system at a speed of 2 m / s. The results, including the comparison with water used for urban water supply, are shown in Table 1.

Three different semi-permeable, single membranes are used, the indices for which are given in Table 2.

The feed coming from the washing step, which is fed to the intermediate product concentrator, is used as the feed stream. The feed stream at a temperature of 17 ° C and at a pressure of 27 atm is circulated at a speed of 1.6 m / s.

The results are shown in table 3.

PRI me R 2 (known). Corn is soaked in water. The capacity of the installation where the method is carried out is 1000 tons / day. The amount of water supplied to the lock vat with corn is 150 tons / day and 1029 tons / day is supplied from the next stage of the process. The amount of lock water coming out of the castle vat is 564 tons / day, and the amount of water with corn supplied for grinding is 615 tons / day. At the grinding stage, the germ, fiber, gluten, and starch are separated. The amount of water bound to germ, fiber and gluten is 317 tonnes / day, while the resulting starch suspension contains 1000 tonnes / day water. The starch suspension is then washed and a washed starch suspension is obtained, containing 841 tons of water / day. Fresh water is supplied to the washing stage in the amount of 1,572 tons / day, and the water output from the washing stage is 1,731 tons / day.

thirty

Example 3. The process is carried out in a wet-grinding plant for corn (Fig. 1). The installation includes a soaking tank 1, in which the corn is soaked in water for 40-48 hours at. The capacity of the plant is 1000 tons / day and the amount of water entering the tank is 150 tons / day with corn (in pipeline 2) and 745 tons / day (in pipe 35, wire 3) from the next stage of the installation. From the plant comes out water in the amount of 280 tons / day in the form of castle water (via pipeline 4) and 615 tons / day

substances, g / l 13,, 4 and divided into two parts. Part of the pipeline 12 in the amount of 1163 tons / day recycle directly to stage 6, while the other part of the pipeline 13 in the amount of 368 tons / day passed through the installation of 14 reverse osmosis. This installation uses a membrane that holds 95% NaCl and passes a stream of fresh water 44 at a pressure of 40 atm and temperature. The raw material at a temperature and 25 pressure of 40 atm is circulated in a reverse osmosis unit at a speed of 2 m / s. The water passing through pipeline 15 through the membrane in the amount of 284 tons / day has the following composition:

Nitrogen, mn. d.6

Stiffness, g1.25

C1 ppm. Less than 3 Transmission

(BOOH10 M 4 cm),% 97.1 pH2.7 Dry matter, g / l0.22 Soluble substances, g / l0.22 and it is recycled by supplying soaked corn (piping 40 fresh water per wash stage 1U 5) which is served on the next - starch. The solution through the pipeline 16,

leaving the reverse osmosis system, which did not pass through the membrane 6 of the installation, where it is ground at a temperature of about 35 ° C and from which the embryos are separated in hydroclones, then the fibers - on sieves, and gluten and starch - on centrifuges. The amount of water (in line 7) associated with germ, fiber and gluten, 317 tons / day, while starch obtained from the centrifuge (in pipe water 8) contains water 1000 tons / day. The resulting starch slurry is then washed using a series of hydroclones 9, and a washed starch slurry containing 841 tons / day of water (in line 10) is obtained. Fresh water is supplied to the pro-washing stage (via pipeline 11) in the amount of 1288 tons / day.

well (concentrate) in the amount of 284 t / 45 / day has the following composition: Nitrogen, ppm 1710 C1 ppm

pH3.8

Dry matter, g / l 27.8 50 Soluble substances, g / l 22.6 This solution is recycled to stage 6.

A comparison of this method with the known method, in which reverse osmosis is not used, shows that the latter requires 1,572 tons / day of fresh water, with 564 tons / day forming a charge. wet water.

and the water leaving the washing stage is 1,731 tons / day.

This water has the following composition:

five

860 26 35

3.7

five

Nitrogen, ppm Stiffness, ° F C1, ppm

ph

Dry matter

g / l13,9

Soluble

substances, g / l 13,, 4 and divided into two parts. Part of the pipeline 12 in the amount of 1163 tons / day recycle directly to stage 6, while the other part of the pipeline 13 in the amount of 368 tons / day passed through the installation of 14 reverse osmosis. This installation uses a membrane that holds 95% NaCl and passes a stream of fresh water 44 at a pressure of 40 atm and temperature. The raw material at a temperature and 5 pressure of 40 atm is circulated in a reverse osmosis unit at a speed of 2 m / s. The water passing through pipeline 15 through the membrane, in the amount of 284 tons / day, has the following composition:

Nitrogen, mn. d.6

Stiffness, g1.25

C1 ppm. Less than 3 Transmission

(BOOH10 M 4 cm),% 97.1 pH2.7 Dry matter, g / l0.22 Soluble substances, g / l0.22 and it is recycled through the fed (concentrate) in the amount of 284 t / day has the following composition: Nitrogen , ppm 1710 C1 ppm

pH3.8

Dry matter, g / l 27.8 Soluble substances, g / l 22.6 This solution is recycled to stage 6.

A comparison of this method with a known method, in which reverse osmosis is not used, shows that the latter requires 1,572 tons / day of fresh water, with 564 tons / day forming a-. wet water.

51369673

Although the total amount of wash water used in the wash stage remains the same (1,572 tons / day), the amount of fresh water supplied is reduced by 284 tons / day to 1,288 tons / day as compared with the known method. Thus, the amount of water supplied from the system in the form of a lock

the stream is then directed to the gluten production stage 20, where gluten 21 is released. The product leaving this plant is divided into two streams, one of which is subjected to reverse osmosis 22 and split into the first fraction (permeate) with a low content of soluble and insoluble

water decreases from 564 tonnes per day according to 10 substances and the second fraction (B starch).

but a known method to 280 tons / day.

PRI me R 4 (known). Potatoes are used as feedstock. It is ground, the juice, fibers are separated, the starch is concentrated and washed.

1000 tons / day of crushed potatoes are fed to the plant at the juice separation stage. Fresh water is supplied at two points: 800 tons / day to the fiber separation stage 20 (starch concentration) and 2700 tons / day to the last stage of the starch washing step. Receive, t / day: juice 803; fibers 33.5;

The starch 23 is separated and transferred to a concentration step 24, where the effluent 25 is withdrawn and made into starch 26. In the meantime, the first fraction 15 (permeate) is recycled and mixed with fresh water 27 entering the system in the last stage 28 washing And starch. From this washing step, the starch is fed to the dewatering stage 29, the fibers 30 and the outgoing product 31 are removed and A starch is obtained.

Such a system allows to reduce

waste water 3373,5; washed with slurry need for fresh water for a quantity of starch 290. If the other conditions are kept constant, increasing the amount of fresh water to wash the starch leads to an increase in the amount of waste water.

In parallel, the process of the proposed method. The difference from the known method is that the water leaving the first stage of the starch washing step is divided into two fractions using reverse osmosis, from which the first is recycled to the starch washing stage, and the second is directed to the juice fiber (starch concentration).

Thus, although the total amount of wash water used is still the same (2,700 tons / day), the amount of fresh water supplied is reduced by half compared to the known method (up to 1,350 tons / day). In the same way, the amount of drainage water removed is reduced from 3373.5 to 2023.5 tons / day.

Example 5. Production of starch from wheat flour is explained in the flowchart shown in Fig. 2. Wheat flour 17 is suspended at the initial preparatory stage 18 and transferred to the next stage 19, where it is divided into a stream rich in starch (A), and a stream rich in gluten. Last

the stream is then directed to the gluten production stage 20, where gluten 21 is released. The product leaving this plant is divided into two streams, one of which is subjected to reverse osmosis 22 and split into the first fraction (permeate) with a low content of soluble and insoluble

20

The starch 23 is separated and sent to a concentration step 24, where the effluent 25 is removed and made into starch 26. Meanwhile, the first fraction (permeate) is recycled and mixed with fresh water 27 entering the system at the last stage 28 washing And starch. From this washing step, the starch is fed to the dewatering stage 29, the fibers 30 and the outgoing product 31 are removed and A starch is obtained.

Such a system allows to reduce

A product equal to the amount of permeate coming from the reverse osmosis unit and reduces the amount of product released that needs to be evaporated or subjected to another type of treatment. The size of the concentration equipment can also be reduced. The quality of starch can be controlled by adjusting the amount of permeate produced and recycled. Since wheat has high concentrations of enzymes and salts, the leaching of starch from sackcloth requires careful monitoring.

The proposed method thus makes it possible to reduce the consumption of fresh water in the process.

F

formula of invention

45

A method for producing starch, which involves grinding the starch-containing raw material, isolating the starch suspension from the crushed raw material, purifying it and then washing the starch suspension in several stages with introducing fresh water to the last washing stage, directing it in 1);

steps per step in countercurrent with the washed suspension and removal of the washed starch suspension, characterized in that, in order to reduce water consumption in the process.

7136.9673

water from the washing stage or a separation containing less than 1000 bpd neither the starch suspension is subjected to protein, and this fraction is returned to reverse osmosis with the formation of a water mixture in the process with fresh water.

Table 1

860

26 35

%

1710

67

3.7

13.9

13, 4

3.8

27.8

22,6

Nitrogen analyzes were performed on filtered samples.

table 2

1394 1350 1385

67 61 56

- -

0.5

25.8 39

96.7 7.5

0.3-0 0.5

50.3

102.1

126.9

Table 3

6 10 15 1.0 3.0 1.0

-3 -9

-14

96.8 95.1 95.9

pH

3.7 3.7 3.7 3.7

Dry matter, g / l 44.3

I

Continuation of table. 3

3.1 3.1

3.1

0.10 0.14 0.19

FIG.

26

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Claims (1)

Claim A method for producing starch, comprising crushing starch-> containing raw materials, isolating starch suspension from crushed raw materials, purifying it and then washing the starch suspension in several stages with the introduction of fresh water to the last washing stage, by flushing for 1> step from step to step countercurrent with the washed suspension and the removal of the washed starch suspension, characterized in that, in order to reduce the flow of water to the process, 1 1369673 fractions containing less than 1000 mpn protein, and this fraction is returned to the process with fresh water. Table 1 water from the washing stage or the allocation of a suspension of starch is subjected to reverse osmosis to obtain aqueous Served Pot to Concentrate Membrane Passed Solution City water Nitrogen, ppm 860 * 1710 6 0.5 Hardness ° F 26 1.25 25.8 C1 ч, ppm, 35 67 3 39 Transmission (bOOhY ' ⁹ 4 cm), 7 7 - - 97.1 96.7 pH 3,7 3.8 2.7 7.5 Dry matter, g / l 13.9 27.8 0.2 0.3-0 Soluble substances, g / l 13,4 22.6 0.22 0.5 Analysis for nitrogen is carried out on filtered samples. table 2 Membrane Delaying Flow clean on the NaCl water (at 7 10 atm. and 14 ° C), l m ² / 1 92.8 50.3 2 73.3 102.1 3 59.8 126.9 Table 3 reach, ° F C1, ‘ ppm 67 61 56 Transmission% 96.8 95.1 95.9 1369673, Continuation of table.Z Innings Membrane concentrate Diaphragm flow 1 2 3 1 _L ² . L .. ³ .. _ pH 3.7 3.7 ’3.7 3.7 3.1 3.1 3.1 Dry matter, g / l 44.3 - - - 0.10 0.14 0.19 * Analysis for nitrogen is carried out on filtered samples. Figure 1 Fig 2