阅读说明：本技术 一种玉米淀粉湿磨加工工艺和初级浓缩工艺 (Corn starch wet milling processing technology and primary concentration technology ) 是由 裴成利 刘泽龙 宫巍 赵永武 于元德 秦善杰 杨佳 于 2020-05-08 设计创作，主要内容包括：本发明涉及一种新的玉米淀粉湿磨加工工艺和初级浓缩工艺,以及用于上述工艺的玉米淀粉湿磨加工系统。相较于传统道尔工艺,本发明的初级浓缩工艺和玉米淀粉湿磨加工工艺和系统从工艺角度对不同浓度的物料进行分类并采用相适应的设备,可以从整体上实现物尽其用,从而大大降低预浓缩和主离心机的运行负荷,节约大量能耗。(The invention relates to a novel corn starch wet milling processing technology and a primary concentration technology, and a corn starch wet milling processing system for the technology. Compared with the traditional Dalton process, the primary concentration process and the corn starch wet-milling process and system classify materials with different concentrations from the process perspective and adopt corresponding equipment, so that the best use of the materials can be realized integrally, the operation loads of the pre-concentration process and the main centrifugal machine are greatly reduced, and a large amount of energy consumption is saved.)

1. A corn starch wet milling processing technology comprises the following steps:

(1) after the corn is soaked and crushed, separating by a separating screen I to obtain separating screen I thick pulp and separating screen I oversize products;

(2) fine grinding the oversize material of the separating screen I to obtain fine ground liquid;

(3) separating the fine ground liquid by a separating screen II to obtain thick slurry of the separating screen II and oversize products of the separating screen II;

(4) enabling oversize materials of the separating screen II to enter a fiber washing and screening system to obtain slurry a and oversize materials for extracting fibers; optionally, splitting at least a portion of slurry a into slurry a1 and slurry a 2;

(5) enabling the separating screen I thick slurry, the separating screen II thick slurry and the optional thin slurry a1 to enter a cyclone for further concentration to obtain concentrated starch milk I of underflow and thin slurry b of overflow;

(6) feeding said slurry a, slurry b and optionally slurry a2 to a preconcentration centrifuge to obtain a crude concentrate and produce process water;

(7) feeding the crude concentrated solution into a main separation centrifuge to obtain concentrated starch milk II of bottom flow and gluten liquid of top flow;

(8) subjecting the gluten liquid to gluten concentration to further obtain a concentrated gluten liquid while producing process water; and

(9) and refining the concentrated starch milk I and II in a washing and refining system to obtain refined starch milk.

2. A primary concentration process for wet processing of corn starch, the primary concentration process comprising the steps of:

(1) after the corn is soaked and crushed, separating by a separating screen I to obtain separating screen I thick pulp and separating screen I oversize products;

(2) fine grinding the oversize material of the separating screen I to obtain fine ground liquid;

(3) separating the fine ground liquid by a separating screen II to obtain thick slurry of the separating screen II and oversize products of the separating screen II;

(4) enabling oversize materials of the separating screen II to enter a fiber washing and screening system to obtain slurry a and oversize materials for extracting fibers; optionally, splitting at least a portion of slurry a into slurry a1 and slurry a 2; and

(5) and (3) enabling the separation screen I concentrated slurry, the separation screen II concentrated slurry and the optional slurry a1 to enter a cyclone for further concentration, and obtaining concentrated starch milk I of underflow and slurry b of overflow for further concentration and/or refining.

3. The corn starch wet milling process or the primary concentration process as claimed in claim 1 or 2, wherein in the step (1), the steeping of the corn is performed with the antacid water having pH of 3.3-3.5, preferably 3.35-3.45;

preferably, in the step (1), the soaking time is 38-48 h, preferably 42-46 h;

preferably, in the step (1), the crushing process is carried out at the rotating speed of 1450-;

preferably, in the step (1), the sieve opening of the separating sieve I is 45 μm to 60 μm, preferably 48 μm to 55 μm, and the operating pressure is 0.2MPa to 0.4MPa, preferably 0.3MPa to 0.4 MPa.

4. The corn starch wet milling process or the primary concentration process as claimed in any one of claims 1 to 3, wherein in step (2) the fine grinding is performed at a rotation speed of 2900-;

preferably, in the step (2), the obtained fine grinding fluid contains: 393 and 485 kg/min of starch, preferably 402 and 416 kg/min; the fiber is 92-141 kg/min, preferably 95-110 kg/min; water 1241-.

5. The corn starch wet milling process or primary concentration process of any one of claims 1-4, wherein in step (3) the separating screen II is a pressure trommel;

preferably, in the step (3), the pore diameter of the pressure curved sieve is less than or equal to 60 μm, preferably less than or equal to 50 μm;

preferably, in the step (3), the operating pressure of the separation screen II is in the range of 0.2MPa to 0.4MPa, preferably 0.3MPa to 0.35 MPa;

preferably, in the step (3), the undersize thick slurry of the separation screen II comprises: 69-109 kg/min starch, preferably 93-101 kg/min; water 239-;

preferably, in the step (3), the oversize material of the separating screen II comprises: the starch is 285-410 kg/min, preferably 300-395 kg/min; fiber 92-141 kg/min, preferably 95-141 kg/min; water 923-1410 kg/min, preferably 952-1410 kg/min.

6. The corn starch wet milling process or primary concentration process as claimed in any one of claims 1 to 5, wherein in step (4) the fiber wash screen system has a mesh size of 70 μm to 80 μm, preferably 72 μm to 78 μm, and an operating pressure of 0.2MPa to 0.4MPa, preferably 0.25MPa to 0.35 MPa;

preferably, in the step (4), the slurry a comprises: starch 277-392 kg/min, preferably 292-379 kg/min; 2812 and 3243 kg/min of water;

preferably, in the step (4), the whole of the slurry a is divided into slurry a1 and slurry a 2.

7. The corn starch wet milling process or the primary concentration process as claimed in any one of claims 1 to 6, wherein in step (5) the cyclone is in stage 1 to 2, preferably the cyclone is in stage 1;

preferably, in the step (5), the specification model of the cyclone is selected fromAndone or more combinations of;

preferably, in the step (5), the number of the pipes of the cyclone is 316-;

preferably, in the step (5), the feeding pressure of the cyclone is 0.65-0.8MPa, preferably 0.65-0.75 MPa;

preferably, in the step (5), the feed of the cyclone comprises: starch 413-864 kg/min, preferably 489-763 kg/min; 5209 kg/min of water 1858-;

preferably, in the step (5), the concentrated starch milk I includes: starch 372-778 kg/min, preferably 440-662 kg/min; 790 kg/min of water, 1654 kg/min, preferably 935 kg/min and 1410 kg/min;

preferably, in the step (5), the slurry b comprises: 43-86 kg/min starch, preferably 49-75 kg/min starch; water 1109-3555 kg/min, preferably 1245-3125 kg/min.

8. The wet milling process for corn starch as claimed in any one of claims 1 to 7, wherein in step (6), the rotation speed of the pre-concentration centrifuge is 2700-;

preferably, in step (6), the feed to the pre-concentration centrifuge comprises: 77-428 kg/min of starch, preferably 144-351 kg/min; water 3836-4353 kg/min, preferably 3773-4340 kg/min;

preferably, in the step (6), the amount of the process water generated by the pre-concentration centrifuge is 2730-3552 kg/min, preferably 2930-3442 kg/min;

preferably, in the step (6), the crude concentrated solution comprises: starch 258-602 kg/min, preferably 312-515 kg/min; water 3210-;

preferably, the process water obtained in step (6) is recycled for use in the preparation of the acid water in step (1).

9. The wet milling process for corn starch as claimed in any one of claims 1 to 8, wherein in the step (7), the rotation speed of the main separation centrifuge is 2300 and 2500 rpm, preferably 2400 and 2480 rpm;

preferably, in the step (7), the concentrated starch milk II contains: starch 269-612 kg/min, preferably 321-594 kg/min; water 572 + 1305 kg/min, preferably 680 + 1262 kg/min;

preferably, in the step (7), the gluten liquid comprises: 7.8-11 kg/min, preferably 7.8-9 kg/min of starch; 2837 and 3268 kg/min of water, preferably 2878 and 3267 kg/min of water;

preferably, in the step (8), the gluten concentration is performed by a gluten concentration separator;

preferably, in the step (8), the amount of the process water generated by the gluten concentration separator is 2757-3177 kg/min, preferably 2798-3176 kg/min;

preferably, in the step (9), the operation pressure of the washing and refining system is 0.7MPa-0.9MPa, preferably 0.75MPa-0.85 MPa;

preferably, in the step (9), the refined starch milk comprises: starch 758-; water 1096-1190 kg/min, preferably 1118-1190 kg/min.

10. A corn starch wet milling process system, wherein the system comprises:

a crushing system;

a separation screen I connected in fluid communication downstream of the crushing system;

a refining connected in fluid communication downstream of the screen I;

a separation screen II connected in fluid communication downstream of said refining;

a fiber washing and screening system connected in fluid communication downstream of the separation screen II;

a cyclone connected in fluid communication downstream of the separation screen I and the separation screen II;

a pre-concentration centrifuge connected in fluid communication downstream of the fiber wash screen system and the cyclone;

a primary centrifuge connected in fluid communication downstream of the preconcentration centrifuge;

a gluten concentration separator connected in fluid communication downstream of the primary centrifuge; and

a wash refinement system connected in fluid communication downstream of the main separation centrifuge and the cyclone.

Technical Field

The invention relates to a corn starch wet grinding processing technology and a material primary concentration technology for starch wet processing, belonging to the technical field of food processing.

Background

Wet milling is the basic process for corn starch production, and is used in essentially all corn starch production worldwide. As shown in fig. 1, in the wet grinding stage of the conventional wet corn processing technology, coarse crushing, embryo extraction and re-crushing are generally adopted, a 'thick slurry' is obtained from the screen bottom through a separating screen I, the screen top is continuously ground and crushed, then the ground slurry is washed and screened to obtain a 'thin slurry', fibers in the screen top are extracted, and the thick slurry and the thin slurry are mixed to obtain the coarse slurry. Then pre-concentrating the coarse pulp, performing main separation and gluten concentration to collect concentrated gluten liquid and obtain process water; the main separation bottom flow is washed by refined cyclone, and refined starch milk is collected.

In the process, the raw slurry (also called raw starch milk) still contains a large amount of insoluble proteins and soluble substances. Chemical composition of dry matter of crude starch milk (calculated on dry basis): 89-92% of starch, 6-8% of protein (Nx 6.25), 0.5-1% of fat, 0.1-0.3% of soluble substances, 0.2-0.3% of ash and the like. The content of these impurities, particularly insoluble proteins, contained in the crude starch milk is still high and further separation is required. The principle of separating starch and protein (gluten) is mainly to utilize the relative density and particle size of the two substances to carry out centrifugal separation, wherein the particle size of the starch is 3-30 mu m, the particle size of the gluten is 1-2 mu m, but the gluten has strong hydrophilicity and can form larger aggregates, and the size of the aggregates can reach 140-170 mu m; the relative density of starch was 1.61 and the relative density of gluten was 1.18.

The starch purification and protein concentration of the coarse pulp are mainly realized by centrifugal separation. The centrifugal separator for corn starch is divided into a starch milk pre-concentration separator, a main separator, a gluten concentration separator and the like. The pre-concentration separator can concentrate the starch milk from 6-7 DEG Be to 12-14 DEG Be. The main separator is mainly used for separating starch and gluten, most insoluble and soluble protein and a small amount of fine granular starch can be separated, the part of the material separated from overflow is called gluten water, and the starch milk can be concentrated from 6 DEG to 12 DEG Be to 17 DEG Be to 19 DEG Be. The gluten concentration separator is used for concentrating the gluten water separated by the main separator, and the concentration of the dry gluten water can be concentrated to 120-130 g/L.

The concentration of the starch milk before pre-concentration feeding is generally 10-14 degrees Bx (5.5-7.7 degrees Be), and the starch milk comprises 89-92% of starch, 6-8% of protein, 0.5-1% of fat, 0.1-0.3% of soluble substances and 0.2-0.3% of minerals. The concentration of the underflow starch milk after the main separation is 28-32 degrees Bx (15.3-17.5 degrees Be), and the underflow starch milk contains 1.5-2.5% of protein. 1-2% of overflow gluten water-dried substance after main separation, and the content of starch is less than 20%.

However, the wet processing of corn starch has always been characterized by high energy and water consumption. Therefore, a simpler and lower-cost method is still required to be explored in the field, so that cost reduction and efficiency improvement, low carbon and environmental protection are realized.

Disclosure of Invention

Aiming at the technical problems, the inventor researches and discovers a corn starch wet-milling processing technology and a primary concentration technology, the technology adds a set of pressure curved screen (separation screen II) at the downstream of fine milling and adds a set of cyclone at the downstream of the separation screen I and the separation screen II, the milled liquid after the fine milling is separated into slurry through the separation screen II, the separated thick slurry does not enter a pre-concentration centrifugal machine any more, but enters the cyclone for primary concentration, and concentrated starch milk is obtained. The concentrated starch milk separated by the primary concentration process can bypass a centrifuge system and directly enter a starch refining cyclone group for refining (figure 2). This variation is relative to the conventional dalton process, which is referred to as the primary concentration process. In addition, the process may also divert a portion of the slurry in the fiber washing and screening system to a cyclone. The process can reduce the load of the centrifuge in the steps of pre-concentration, main separation and the like, thereby reducing the consumption of power energy of the centrifuge.

Accordingly, in a first aspect, the present invention provides a corn starch wet milling process comprising the steps of:

(1) after the corn is soaked and crushed, separating by a separating screen I to obtain separating screen I thick pulp and separating screen I oversize products;

(2) fine grinding the oversize material of the separating screen I to obtain fine ground liquid;

(3) separating the fine ground liquid by a separating screen II to obtain thick slurry of the separating screen II and oversize products of the separating screen II;

(4) enabling oversize materials of the separating screen II to enter a fiber washing and screening system to obtain slurry a and oversize materials for extracting fibers; optionally, splitting at least a portion of slurry a into slurry a1 and slurry a 2;

(5) enabling the separating screen I thick slurry, the separating screen II thick slurry and the optional thin slurry a1 to enter a cyclone for further concentration to obtain concentrated starch milk I of underflow and thin slurry b of overflow;

(6) feeding said slurry a, slurry b and optionally slurry a2 to a preconcentration centrifuge to obtain a crude concentrate and produce process water;

(7) feeding the crude concentrated solution into a main separation centrifuge to obtain concentrated starch milk II of bottom flow and gluten liquid of top flow;

(8) subjecting the gluten liquid to gluten concentration to further obtain a concentrated gluten liquid while producing process water; and

(9) and refining the concentrated starch milk I and II in a washing and refining system to obtain refined starch milk.

In a second aspect, the present invention provides a primary concentration process for wet processing of corn starch, the primary concentration process comprising the steps of:

(1) after the corn is soaked and crushed, separating by a separating screen I to obtain separating screen I thick pulp and separating screen I oversize products;

(2) fine grinding the oversize material of the separating screen I to obtain fine ground liquid;

(3) separating the fine ground liquid by a separating screen II to obtain thick slurry of the separating screen II and oversize products of the separating screen II;

(4) enabling oversize materials of the separating screen II to enter a fiber washing and screening system to obtain slurry a and oversize materials for extracting fibers; optionally, splitting at least a portion of slurry a into slurry a1 and slurry a 2; and

(5) and (3) enabling the separation screen I concentrated slurry, the separation screen II concentrated slurry and the optional slurry a1 to enter a cyclone for further concentration, and obtaining concentrated starch milk I of underflow and slurry b of overflow for further concentration and/or refining.

In a third aspect, the present invention provides a corn starch wet milling processing system, wherein the system comprises:

a crushing system;

a separation screen I connected in fluid communication downstream of the crushing system;

a refining connected in fluid communication downstream of the screen I;

a separation screen II connected in fluid communication downstream of said refining;

a fiber washing and screening system connected in fluid communication downstream of the separation screen II;

a cyclone connected in fluid communication downstream of the separation screen I and the separation screen II;

a pre-concentration centrifuge connected in fluid communication downstream of the fiber wash screen system and the cyclone;

a primary centrifuge connected in fluid communication downstream of the preconcentration centrifuge;

a gluten concentration separator connected in fluid communication downstream of the primary centrifuge; and

a wash refinement system connected in fluid communication downstream of the main separation centrifuge and the cyclone.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) the invention provides a novel primary concentration process for wet processing of corn starch, which classifies materials with different concentrations from the process perspective, and then adopts adaptive equipment to make the best use of things on the whole, thereby achieving the purposes of optimizing the process, purifying the process and perfecting the process.

(2) The corn starch wet milling processing technology uses a primary concentration technology, and compared with the traditional Dalton technology, the technology of the invention enables the feed starch milk amount of a pre-concentration centrifugal machine to be reduced by 56-129 tons/hour, and reduced by 16.5% -35.5%; the feeding amount of the starch milk of the main centrifugal machine is reduced by 61-167 tons/hour, and reduced by 17% -45%, so that the operation load of the pre-concentration and the main centrifugal machine can be greatly reduced, and a large amount of energy consumption is saved.

(3) The primary concentration process of the invention adds a set of pressure curved screen (i.e. separating screen II) and cyclone, reduces the process dependence on high energy consumption equipment disc centrifuge, and in the process, the equipment investment of the centrifuge is saved by at least half of the equipment investment of the centrifuge with small investment, thereby obviously reducing the equipment investment. The separation screen II (pressure curved screen) specially arranged in the process can convert the fine grinding product into thick slurry as much as possible and then enters the cyclone, so that the liquid entering the pre-concentration and main separator is thin slurry as much as possible, the centrifugal load of a part of the centrifugal load is divided by the cyclone with lower energy consumption on the basis of the centrifuge with higher energy consumption, the energy consumption is reduced, the process dependence on a disc centrifuge with high energy consumption equipment is further reduced, the equipment investment of the centrifuge is saved by at least half of the equipment investment in the process by using small investment, and the equipment investment is obviously reduced.

(4) Generally, the quality of the acid making water when the corn is soaked in the soaking process is one of the factors influencing the quality of the soaked corn. The water used for acid production is mainly fresh water and process water produced in the gluten concentration process. The quality of the produced sulfurous acid solution is different due to different quality of the acid preparation water, the quality of the fresh water is good, the produced sulfurous acid solution has clean and pure quality, and the osmotic pressure of the sulfurous acid solution is high. Different process technologies produce different quality of process water (different content of dry matter, suspended matter, soluble matter and the like), the quality of the produced sulfurous acid solution has certain difference, and the soluble matter has larger influence on osmotic pressure of the produced sulfurous acid solution. The content of dry matters, suspended matters, soluble matters and the like in the process water obtained by the traditional Dalton process is high, and ideal effects are difficult to realize when the process water is recycled for soaking corns.

The primary concentration process of the invention promotes the reduction of the dry matter content of the top flow of the centrifuge by reducing the load of the centrifuge, and correspondingly reduces the dry matter, suspended matter, soluble matter and other contents of the produced process water, thereby realizing the purification and quality improvement of the process water of the whole production process. Compared with the traditional process, the process water can be effectively recycled for soaking the corn, so that the acid-making soaking process is effectively improved, the indexes of soluble substance content and the like of the soaked corn are correspondingly improved, and the optimization and progress of the whole process are realized.

Drawings

Fig. 1 is a schematic view showing a process flow of a conventional corn wet processing process.

FIG. 2 is a schematic diagram showing the process flow of the corn wet processing process incorporating the primary concentration process of the present invention.

Fig. 3 is a schematic diagram showing the overall reduction of process water dryness in examples of the present invention relative to comparative examples.

FIG. 4 is a schematic showing the reduction in post-steeping corn solubles in examples of the invention relative to a comparative example.

Detailed Description

The inventor researches and discovers that a set of pressure curved screen (separating screen II) and a set of swirler are additionally arranged, ground liquid after fine crushing is subjected to pulp separation through a screening device I and a screening device II, and the separated thick pulp does not enter a pre-concentration centrifugal machine any more, but enters the swirler for primary concentration. The starch milk obtained by separation can bypass a centrifuge system and directly enter a starch refining cyclone group for refining, so that the equipment asset investment can be obviously reduced, the energy consumption is reduced, and the quality of process water and the protein yield are improved.

In some embodiments, the present invention provides a corn starch wet milling process comprising the steps of:

(1) after the corn is soaked and crushed, separating by a separating screen I to obtain separating screen I thick pulp and separating screen I oversize products;

(2) fine grinding the oversize material of the separating screen I to obtain fine ground liquid;

(3) separating the fine ground liquid by a separating screen II to obtain thick slurry of the separating screen II and oversize products of the separating screen II;

(4) enabling oversize materials of the separating screen II to enter a fiber washing and screening system to obtain slurry a and oversize materials for extracting fibers; optionally, splitting at least a portion of slurry a into slurry a1 and slurry a 2;

(5) enabling the separating screen I thick slurry, the separating screen II thick slurry and the optional thin slurry a1 to enter a cyclone for further concentration to obtain concentrated starch milk I of underflow and thin slurry b of overflow;

(6) feeding said slurry a, slurry b and optionally slurry a2 to a preconcentration centrifuge to obtain a crude concentrate and produce process water;

(7) feeding the crude concentrated solution into a main separation centrifuge to obtain concentrated starch milk II of bottom flow and gluten liquid of top flow;

(8) subjecting the gluten liquid to gluten concentration to further obtain a concentrated gluten liquid while producing process water; and

(9) and refining the concentrated starch milk I and II in a washing and refining system to obtain refined starch milk.

In some embodiments, the present invention provides a primary concentration process for wet processing of corn starch, the primary concentration process comprising the steps of:

(1) after the corn is soaked and crushed, separating by a separating screen I to obtain separating screen I thick pulp and separating screen I oversize products;

(2) fine grinding the oversize material of the separating screen I to obtain fine ground liquid;

(3) separating the fine ground liquid by a separating screen II to obtain thick slurry of the separating screen II and oversize products of the separating screen II;

(4) enabling oversize materials of the separating screen II to enter a fiber washing and screening system to obtain slurry a and oversize materials for extracting fibers; optionally, splitting at least a portion of slurry a into slurry a1 and slurry a 2; and

(5) and (3) enabling the separation screen I concentrated slurry, the separation screen II concentrated slurry and the optional slurry a1 to enter a cyclone for further concentration, and obtaining concentrated starch milk I of underflow and slurry b of overflow for further concentration and/or refining.

In some embodiments, the crushing process in step (1) above is performed at 1450-. Preferably, the sieve pores of the separating sieve I are 45-60 μm, preferably 48-55 μm, and the operating pressure is 0.2-0.4 MPa, preferably 0.3-0.4 MPa. Preferably, the steeping of the corn is performed with an acid water having a pH of 3.3-3.5, preferably 3.35-3.45; preferably, the soaking time is 38-48 h, preferably 42-46 h.

In some embodiments, said refining in step (2) above is performed at a rotational speed of 2900-. Preferably, the obtained fine ground liquid comprises: 393 and 485 kg/min of starch, preferably 402 and 416 kg/min; the fiber is 92-141 kg/min, preferably 95-110 kg/min; water 1241-.

In some embodiments, the separation screen II in the above step (3) may be a pressure curved screen. Preferably, the pore diameter of the pressure curved sieve is less than or equal to 60 μm, preferably less than or equal to 50 μm. Preferably, the operating pressure range of the separating screen II is 0.2MPa-0.4MPa, preferably 0.3MPa-0.35 MPa.

Preferably, the undersize thick stock of separating screen II comprises: 69-109 kg/min starch, preferably 93-101 kg/min; water 239-. Preferably, the oversize of the separating screen II comprises: the starch is 285-410 kg/min, preferably 300-395 kg/min; fiber 92-141 kg/min, preferably 95-141 kg/min; water 923-1410 kg/min, preferably 952-1410 kg/min.

In some embodiments, the fiber washing and screening system in step (4) above has a mesh size of 70 μm to 80 μm, preferably 72 μm to 78 μm, and an operating pressure of 0.2MPa to 0.4MPa, preferably 0.25MPa to 0.35 MPa. Preferably, the fiber washing and screening system obtains slurry a comprising: 283-379 kg/min of starch, 292-379 kg/min of starch; water 2812-3243 kg/min, preferably 2980-3243 kg/min.

The fiber washing and screening system in the step (4) adopts a countercurrent washing and screening method, the fiber, starch and protein mixed solution enters from the front end of the system, the washing process water enters from the rear end and is washed and separated step by step, so that the starch, protein and fiber are separated to the maximum extent, starch and protein slurry is separated and extracted from the front end of the system, and the fiber is separated from the rear end of the system.

In some embodiments, at least a portion of slurry a is split into slurry a1 and slurry a2 in step (4) above. Preferably, the whole of slurry a is split into slurry a1 and slurry a 2. Preferably, the slurry a (slurry a1 ingredient: slurry a2 ingredient) comprises: starch 277-392 kg/min, preferably 292-379 kg/min; 2812 and 3243 kg/min of water.

In the present invention, the division of the slurry a into the slurry a1 and the slurry a2 does not change the compositions of the slurries before and after the division, and the slurry a, the slurry a1 and the slurry a2 are the same in composition. The inventors have found that by splitting slurry a in step (4) above (where slurry a1 is split to the cyclone and slurry a2 is split to the preconcentration centrifuge), the main centrifuge operating load can be further reduced.

In some embodiments of the present invention, the substrate is,the cyclone in the step (5) is 1-2 stages, and preferably, the cyclone is 1 stage. Preferably, the size of the cyclone is selected fromAndone or more of the above. Preferably, the number of the tubes of the cyclone is 316-. Preferably, the feed pressure of the cyclone is between 0.65 and 0.8MPa, preferably between 0.65 and 0.75 MPa.

Preferably, the feed to the cyclone in the step (5) comprises: starch 413-864 kg/min, preferably 489-763 kg/min; water 1858-5209 kg/min, preferably 2182-4533 kg/min. Preferably, the underflow concentrated starch milk I obtained in the step (5) contains 372-778 kg/min starch, preferably 440-662 kg/min starch; 1654 kg/min of water 790 and 1410 kg/min of water are preferred. Preferably, the overflowed slurry b obtained in step (5) above contains 40-86 kg/min, preferably 49-75 kg/min of starch; water 1065-.

In some embodiments, the rotation speed of the pre-concentration centrifuge in step (6) is 2700-. In other embodiments, the rotation speed of the pre-concentration centrifuge in step (6) is 2050-. Preferably, the feed to the preconcentration centrifuge in the above step (6) comprises: 77-428 kg/min of starch, preferably 144-351 kg/min; water 3836-4353 kg/min, preferably 3773-4340 kg/min. Preferably, the amount of process water generated by the pre-concentration centrifuge in the step (6) is 2730-3552 kg/min, preferably 2930-3442 kg/min. Preferably, the crude concentrate (i.e. the pre-concentrated starch milk) obtained in step (6) above comprises: starch 258-602 kg/min, preferably 312-515 kg/min; 3210-. Preferably, the process water obtained in step (6) is recycled for use in the preparation of the acid water in step (1).

In some embodiments, in the step (7), the rotation speed of the main separation centrifuge is 2300 and 2500 rpm, preferably 2400 and 2480 rpm. Preferably, the underflow concentrated starch milk II obtained in step (7) above comprises: starch 269-612 kg/min, preferably 321-594 kg/min; water 572 + 1305 kg/min, preferably 680-1262 kg/min. Preferably, the gluten liquid of the top stream obtained in the step (7) above comprises: 7.8-11 kg/min, preferably 7.8-9 kg/min of starch; water 2837 and 3268 kg/min, preferably 2878 and 3267 kg/min.

The invention makes the material to be separated enter into the centrifuge (enter into the pre-concentration centrifuge and the main separation centrifuge in turn), under the action of centrifugal force, the starch with large specific gravity enters into the solid phase collection cavity and is discharged intermittently from the bottom flow outlet, and the protein with small specific gravity, soluble substance and a large amount of water are discharged from the top flow outlet, thereby further improving the separation and processing effect.

In some embodiments, in the above step (8), the gluten concentration is performed by a gluten concentration separator; preferably, the gluten concentration separator produces a process water amount of 2757-3177 kg/min, preferably 2798-3176 kg/min.

In some embodiments, in step (9) above, the washing and refining system is operated at a pressure of 0.7MPa to 0.9MPa, preferably 0.75MPa to 0.85 MPa. Preferably, the refined starch milk obtained in the step (9) contains 758-; water 1096-1190 kg/min, preferably 1118-1190 kg/min.

In some embodiments, the present invention provides a corn starch wet milling processing system, wherein the system comprises:

a crushing system;

a separation screen I connected in fluid communication downstream of the crushing system;

a refining connected in fluid communication downstream of the screen I;

a separation screen II connected in fluid communication downstream of said refining;

a fiber washing and screening system connected in fluid communication downstream of the separation screen II;

a cyclone connected in fluid communication downstream of the separation screen I and the separation screen II;

a pre-concentration centrifuge connected in fluid communication downstream of the fiber wash screen system and the cyclone;

a primary centrifuge connected in fluid communication downstream of the preconcentration centrifuge;

a gluten concentration separator connected in fluid communication downstream of the primary centrifuge; and

a wash refinement system connected in fluid communication downstream of the main separation centrifuge and the cyclone.

Examples

The present invention will be described in further detail with reference to examples, but the present invention is not limited to these examples. The experimental methods used in the following examples are all conventional methods unless otherwise specified; reagents, materials, devices and the like used in the following examples are commercially available or can be prepared by those skilled in the art according to the ordinary skill in the art, unless otherwise specified.

In the invention, the protein content in the product is determined according to the first Kjeldahl method in the national standard GB 5009.5-2016 for food safety, and the protein conversion coefficient is 6.25. The moisture content of the product was determined according to the method of GB/T5009.3-2016. The starch content in the product is determined according to the national food safety standard GB 5009.9-2016. The fiber content in the product is determined according to the method specified in GB/T6434-2006 filtration method for determining the content of crude fiber in feed.

The following examples are directed to a process configuration for a signature of corn at 14% moisture, with a commercial capacity of 2000 tons/day as the process basis. The method is characterized by preparing fine grinding liquid by a conventional Dalton wet grinding process, and comprises the following steps: soaking the corn raw material for 36-48 h by using acid-making water with pH of 3.6-4.2 to obtain soaked corn, crushing the soaked corn by using a convex tooth mill (Dalianshenrude fluid equipment factory, model: TCM920), obtaining thick slurry of a separation sieve I and oversize of the separation sieve I by using a separation sieve I (Zhuhai Liqi machinery factory, model: YQS710X2), and finely crushing the oversize in an accurate grinding (Chongqing Jiangbei machinery factory, model: LZM1000-NA) to obtain finely ground liquid. The operation or configuration parameters of the partial equipment in the above process and the subsequent process are as follows:

TABLE 1

Example 1

(1) The fine grinding fluid obtained by fine crushing contains: 478 kg/min of starch (mass flow, the same below), 141 kg/min of fiber and 1649 kg/min of water;

(2) and (3) feeding the ground liquid into a pressure curved sieve (YDQS-585, the same below except a special statement, Jiangsu Yihui mechanical equipment Limited) of a separation sieve II to obtain an oversize product and an undersize thick slurry of the separation sieve II, wherein the aperture of the sieve surface of the separation sieve II is 50 mu m, and the operating pressure is 0.35 MPa. The oversize comprises: 409 kg/min of starch, 141 kg/min of fiber and 1410 kg/min of water; the undersize thick pulp comprises: 69 kg/min of starch and 239 kg/min of water;

(3) the oversize from the separation screen II in step 2 was passed to a fiber washing and screening system (Zhuhai Liqi mechanical plant, type: YQS710X4, the same except for the specific statement: screen opening: 75 μm, operating pressure: 0.3MPa) to obtain undersize slurry a and oversize for fiber extraction. Wherein slurry a comprises: 392 kilograms/minute of starch and 3243 kilograms/minute of water;

(4) the thick slurry in step 2 and the thick slurry of the separating screen I are combined and enter a cyclone (level 1, the number of pipes: 415, Clamshell)Fluid-Quip, Inc.), the feed contained: 413 kg/min of starch, 1858 kg/min of water, feeding pressure: 0.65 MPa.After further concentration, underflow concentrated starch milk I and overflow slurry b are obtained. Wherein, slurry b comprises: 41 kg/min of starch and 1068 kg/min of water; the concentrated starch milk I comprises: 372 kg/min of starch and 790 kg/min of water;

(5) and merging the slurry a in the step 3 and the slurry b in the step 4, and then feeding the merged slurry into a pre-concentration centrifuge (German West Valley plant, model: SDA300) to obtain pre-concentrated starch milk (namely crude concentrated solution) and generate process water. Wherein the combined slurry comprises: 428 kg/min of starch and 4311 kg/min of water. The amount of process water is 2731 kg/min. The pre-concentrated starch milk comprises: 602 kg/min of starch and 4330 kg/min of water;

(6) the pre-concentrated starch milk in the step 5 enters a main separation centrifuge (German West Valley plant, model: SDA300) to obtain concentrated starch milk II of the bottom flow and gluten liquid of the top flow. Wherein the gluten liquid of the top flow comprises: 8.9 kg/min of starch and 3268 kg/min of water. The concentrated starch milk II of the underflow comprises: 612 kg/min of starch and 1301 kg/min of water;

(7) concentrating the top flow gluten liquid in the step 6 by a gluten concentration separator to further obtain concentrated gluten liquid and simultaneously generate process water; wherein the process water amount is 3177 kg;

(8) and (3) merging the concentrated starch milk I in the step (4) and the concentrated starch milk II in the step (6), and refining in a washing and refining system (Daliangsheng Ruide fluid equipment factory, model: XDXL480-I) to obtain the refined starch milk. The refined starch milk comprises: 773 kg/min starch and 1118 kg/min water.

Example 2

(1) The grinding fluid obtained by fine crushing contains: 395 kg/min of starch (mass flow, the same below), 92 kg/min of fiber and 1273 kg/min of water;

(2) the ground liquid enters a separation sieve II pressure curved sieve with the sieve surface aperture of 60 mu m, and the pressure is 0.2MPa, so that oversize products and undersize thick pulp of the separation sieve II are obtained. The oversize comprises: 287 kg/min of starch, 92 kg/min of fiber and 923 kg/min of water; the undersize thick pulp comprises: 109 kg/min of starch and 350 kg/min of water;

(3) the oversize of the separating screen II in the step 2 enters a fiber washing and screening system (screen hole: 72 mu m, operating pressure: 0.35MPa), and undersize thin pulp a and oversize for extracting fibers are obtained. Wherein slurry a comprises: 277 kilograms/minute of starch and 2812 kilograms/minute of water;

(4) the thick slurry in the step 2 and the thick slurry of the separating screen I are merged and then enter a cyclone (level 1, the number of pipes is 598, Clamshell)Fluid-Quip, Inc.), the feed contained: 603 kg/min starch, 2680 kg/min water, feed pressure: 0.8 MPa. After further concentration, underflow concentrated starch milk I and overflow slurry b are obtained. Wherein, slurry b comprises: 60 kg/min of starch and 1525 kg/min of water; the concentrated starch milk I comprises: 543 kg/min of starch and 1154 kg/min of water;

(5) and (4) merging the slurry a in the step (3) and the slurry b in the step (4), and then feeding the merged slurry into a pre-concentration centrifugal machine to obtain pre-concentrated starch milk, and generating process water. Wherein the combined slurry comprises: 317 kg/min of starch and 4338 kg/min of water. The amount of process water was 3167 kg/min. The pre-concentrated starch milk comprises: 496 kg/min of starch and 4096 kg/min of water;

(6) and (5) feeding the pre-concentrated starch milk in the step 5 into a main separation centrifuge to obtain concentrated starch milk II of the underflow and gluten liquid of the overflow. Wherein the gluten liquid of the top flow comprises: 11 kg/min of starch and 3265 kg/min of water. The concentrated starch milk II of the underflow comprises: 503 kg/min of starch and 1070 kg/min of water;

(7) concentrating the top flow gluten liquid in the step 6 by a gluten concentration separator to further obtain concentrated gluten liquid and simultaneously generate process water; wherein the amount of process water is 3174 kg;

(8) and (4) merging the concentrated starch milk I in the step (4) and the concentrated starch milk II in the step (6), and then feeding the merged starch milk into a washing and refining system for refining to obtain the refined starch milk. The refined starch milk comprises: 822 kg/min of starch and 1189 kg/min of water.

Example 3

(1) The grinding fluid obtained by fine crushing contains: 402 kg/min of starch (mass flow, the same below), 95 kg/min of fiber and 1270 kg/min of water;

(2) the ground liquid enters a separation sieve II pressure curved sieve with the sieve surface aperture of 45 mu m, and the pressure is 0.4MPa, so that oversize products and undersize thick pulp of the separation sieve II are obtained. The oversize comprises: 301 kg/min of starch, 95 kg/min of fiber and 952 kg/min of water; the undersize thick pulp comprises: 101 kg/min of starch and 318 kg/min of water;

(3) and (3) feeding oversize products of the separation screen II in the step (2) into a fiber washing and screening system (screen holes: 70 mu m, operating pressure: 0.4MPa) to obtain undersize slurry a and oversize products for extracting fibers. Wherein slurry a comprises: 292 kg/min of starch and 2812 kg/min of water;

(4) the thick slurry in the step 2 and the thick slurry of the separating screen I are merged and then enter a cyclone (level 1, the number of pipes: 316, Clamshell)Fluid-Quip, Inc.), the feed contained: 602 kg/min starch, 2678 kg/min water, feed pressure: 0.65 MPa. After further concentration, underflow concentrated starch milk I and overflow slurry b are obtained. Wherein, slurry b comprises: 60 kg/min of starch and 1527 kg/min of water; the concentrated starch milk I comprises: 541 kg/min of starch and 1151 kg/min of water;

(5) and (4) merging the slurry a in the step (3) and the slurry b in the step (4), and then feeding the merged slurry into a pre-concentration centrifugal machine to obtain pre-concentrated starch milk, and generating process water. Wherein the combined slurry comprises: 313 kg/min of starch and 4339 kg/min of water. The amount of process water was 3183 kg/min. The pre-concentrated starch milk comprises: 495 kg/min of starch and 4083 kg/min of water;

(6) and (5) feeding the pre-concentrated starch milk in the step 5 into a main separation centrifuge to obtain concentrated starch milk II of the underflow and gluten liquid of the overflow. Wherein the gluten liquid of the top flow comprises: 8 kg/min of starch and 3247 kg/min of water. The concentrated starch milk II of the underflow comprises: 505 kg/min of starch and 1074 kg/min of water;

(7) concentrating the top flow gluten liquid in the step 6 by a gluten concentration separator to further obtain concentrated gluten liquid and simultaneously generate process water; wherein the amount of process water is 3156 kg;

(8) and (4) merging the concentrated starch milk I in the step (4) and the concentrated starch milk II in the step (6), and then feeding the merged starch milk into a washing and refining system for refining to obtain the refined starch milk. The refined starch milk comprises: 823 kg/min of starch and 1190 kg/min of water.

Example 4

(1) The grinding fluid obtained by fine crushing contains: 416 kg/min starch (mass flow, the same applies below), 110 kg/min fiber and 1420 kg/min water;

(2) the ground liquid enters a separation sieve II pressure curved sieve with the sieve surface aperture of 50 mu m, and the pressure is 0.3MPa, so that oversize products and undersize thick pulp of the separation sieve II are obtained. The oversize comprises: 322 kg/min of starch, 110 kg/min of fiber and 1102 kg/min of water; the undersize thick pulp comprises: 93 kg/min of starch and 318 kg/min of water;

(3) and (3) feeding oversize products of the separation screen II in the step (2) into a fiber washing and screening system (screen hole: 80 mu m, operating pressure: 0.2MPa) to obtain undersize slurry a and oversize products for extracting fibers. Wherein slurry a comprises: 311 kg/min of starch and 2980 kg/min of water;

(4) the thick slurry in the step 2 and the thick slurry of the separating screen I are combined and enter a cyclone (1 level, pipe number: 452, Clamshell)Fluid-Quip, Inc.), the feed contained: 489 kg/min starch, 2182 kg/min water, feed pressure: 0.75 MPa. After further concentration, underflow concentrated starch milk I and overflow slurry b are obtained. Wherein, slurry b comprises: 49 jin/min of starch and 1247 kg/min of water; the concentrated starch milk I comprises: 440 kg/min of starch and 935 kg/min of water;

(5) and (4) merging the slurry a in the step (3) and the slurry b in the step (4), and then feeding the merged slurry into a pre-concentration centrifugal machine to obtain pre-concentrated starch milk, and generating process water. Wherein the combined slurry comprises: 351 kg/min of starch and 4227 kg/min of water. The process water amount is 2931 kg/min. The pre-concentrated starch milk comprises: 515 kg/min of starch and 3993 kg/min of water;

(6) and (5) feeding the pre-concentrated starch milk in the step 5 into a main separation centrifuge to obtain concentrated starch milk II of the underflow and gluten liquid of the overflow. Wherein the gluten liquid of the top flow comprises: 9 kg/min of starch and 3117 kg/min of water. The concentrated starch milk II of the underflow comprises: 524 kg/min of starch and 1115 kg/min of water;

(7) concentrating the top flow gluten liquid in the step 6 by a gluten concentration separator to further obtain concentrated gluten liquid and simultaneously generate process water; wherein, the amount of process water is 3029 kg;

(8) and (4) merging the concentrated starch milk I in the step (4) and the concentrated starch milk II in the step (6), and then feeding the merged starch milk into a washing and refining system for refining to obtain the refined starch milk. The refined starch milk comprises: 758 kg/min of starch and 1096 kg/min of water.

Example 5

(1) The grinding fluid obtained by fine crushing contains: 485 kg/min starch (mass flow, the same below), 141 kg/min fiber and 1729 kg/min water;

(2) the ground liquid enters a separation sieve II pressure curved sieve with the sieve surface aperture of 50 mu m, and the pressure is 0.35MPa, so that oversize products and undersize thick pulp of the separation sieve II are obtained. The oversize comprises: 395 kg/min of starch, 141 kg/min of fiber and 1410 kg/min of water; the undersize thick pulp comprises: 89 kg/min of starch and 318 kg/min of water;

(3) the oversize of the separating screen II in the step 2 enters a fiber washing and screening system (screen hole: 78 mu m, operating pressure: 0.25MPa), and undersize thin pulp a and oversize for extracting fibers are obtained. Wherein slurry a comprises: 379 kg/min of starch and 3243 kg/min of water;

(4) the stock tank of slurry a obtained in step 3 is connected to the cyclone and the preconcentration centrifuge with different pipes and valves, respectively, to divide slurry a into slurry a1 and slurry a2, respectively. Wherein the slurry a1 contains 303 kg/min of starch and 2595 kg/min of water;

(5) the thick slurry in the step 2, the thick slurry of the separating screen I and the thin slurry a1 are merged and enter a cyclone (1 level, pipe number: 433, Clamshell)Fluid-Quip, Inc.), the feed contained: 736 kg/min starch, 4533 kg/min water, feed pressure: 0.65 MPa. After further concentration, underflow concentrated starch milk I and overflow slurry b are obtained. Wherein, slurry b comprises: 74 kg/min of starch and 3124 kg/min of water; the concentrated starch milk I comprises: 662 kg/min of starch and 1408 kg/min of water;

(6) and combining the slurry a2 and the slurry b in the steps 4 and 5, and then feeding the combined slurry into a pre-concentration centrifuge to obtain pre-concentrated starch milk, and generating process water. Wherein the combined slurry comprises: 144 kg/min of starch and 3773 kg/min of water. The amount of process water was 3242 kg/min. The pre-concentrated starch milk comprises: 312 kg/min of starch and 3281 kg/min of water;

(7) and (4) feeding the pre-concentrated starch milk obtained in the step (6) into a main separation centrifuge to obtain concentrated starch milk II of the underflow and gluten liquid of the overflow. Wherein the gluten liquid of the top flow comprises: 9 kg/min of starch and 2837 kg/min of water. The concentrated starch milk II of the underflow comprises: 321 kg/min of starch and 683 kg/min of water;

(8) concentrating the top flow gluten liquid in the step 7 through a gluten concentration separator to further obtain concentrated gluten liquid and simultaneously generate process water; wherein, the amount of process water is 2757 kg;

(9) and (4) merging the concentrated starch milk I in the step (5) and the concentrated starch milk II in the step (7), and then feeding the merged mixture into a washing and refining system for refining to obtain the refined starch milk. The refined starch milk comprises: 773 kg/min starch and 1118 kg/min water.

Example 6

(1) The grinding fluid obtained by fine crushing contains: 402 kg/min of starch (mass flow, the same below), 95 kg/min of fiber and 1270 kg/min of water;

(2) the ground liquid enters a separation sieve II pressure curved sieve with the sieve surface aperture of 50 mu m, and the pressure is 0.4MPa, so that oversize products and undersize thick pulp of the separation sieve II are obtained. The oversize comprises: 301 kg/min of starch, 95 kg/min of fiber and 952 kg/min of water; the undersize thick pulp comprises: 101 kg/min of starch and 318 kg/min of water;

(3) and (3) feeding oversize products of the separation screen II in the step (2) into a fiber washing and screening system (screen holes: 75 mu m, operating pressure: 0.3MPa) to obtain undersize slurry a and oversize products for extracting fibers. Wherein slurry a comprises: 292 kg/min of starch and 2812 kg/min of water;

(4) the stock tank of slurry a obtained in step 3 is connected to the cyclone and the preconcentration centrifuge with different pipes and valves, respectively, to divide slurry a into slurry a1 and slurry a2, respectively. Wherein the slurry a1 contains 263 kg/min of starch and 2531 kg/min of water;

(5) the thick slurry in step 2, the thick slurry of the separating screen I and the thin slurry a1 are merged and enter a cyclone (1 stage, the number of pipes: 316, Clamshell)Fluid-Quip, Inc.), the feed contained: 864 kg/min starch, 5209 kg/min water, feed pressure: 0.65 MPa. After further concentration, underflow concentrated starch milk I and overflow slurry b are obtained. Wherein, slurry b comprises: 86 kg/min of starch and 3555 kg/min of water; the concentrated starch milk I comprises: 778 kg/min starch and 1654 kg/min water;

(5) and (4) merging the slurry a in the step (3) and the slurry b in the step (4), and then feeding the merged slurry into a pre-concentration centrifugal machine to obtain pre-concentrated starch milk, and generating process water. Wherein the combined slurry comprises: 77 kg/min of starch and 3836 kg/min of water. The amount of process water is 3552 kg/min. The pre-concentrated starch milk comprises: 258 kg/min of starch and 3211 kg/min of water;

(6) and (5) feeding the pre-concentrated starch milk in the step 5 into a main separation centrifuge to obtain concentrated starch milk II of the underflow and gluten liquid of the overflow. Wherein the gluten liquid of the top flow comprises: 7.8 kg/min of starch and 2878 kg/min of water. The concentrated starch milk II of the underflow comprises: 269 kg/min of starch and 572 kg/min of water;

(7) concentrating the top flow gluten liquid in the step 6 by a gluten concentration separator to further obtain concentrated gluten liquid and simultaneously generate process water; wherein, the process water amount is 2798 kg;

(8) and (4) merging the concentrated starch milk I in the step (4) and the concentrated starch milk II in the step (6), and then feeding the merged starch milk into a washing and refining system for refining to obtain the refined starch milk. The refined starch milk comprises: starch 823 kg/min. 1190 kg/min of water.

The following comparative examples were conducted on equipment configurations based on a process of 14% moisture of a maize trade mark and 2000 tons/day of processing capacity. And similarly, performing fine grinding and crushing on oversize materials passing through the separating screen I to obtain fine grinding liquid. The process from the fine grinding fluid to the refined starch milk then uses the process shown in fig. 1. Of these, comparative example 1 corresponds to examples 1 and 5, comparative example 2 corresponds to example 2, comparative example 3 corresponds to example 3, comparative example 4 corresponds to example 4, and comparative example 5 corresponds to example 6, and except for the difference between comparative example 1 and example 5, only the primary concentrated fraction differs between the above corresponding examples and comparative examples.

Comparative example 1

(1) A fine grinding fluid was obtained by the same conditions as in example 1;

(2) the ground liquid enters a fiber washing and screening system for washing and screening to obtain slurry under the screen; wherein the slurry comprises 506 kg/min of starch and 4068 kg/min of water;

(3) and (3) mixing the thick slurry of the separating screen I with the thin slurry in the step (2), and then feeding the mixture into a pre-concentration centrifugal machine to obtain concentration, and generating process water and a crude concentrated solution. Wherein, the feed of the pre-concentration centrifugal machine contains 845 kg/min of starch and 4863 kg/min of water; the process water amount is 1746 kg/min; the crude concentrated solution contains 982 kg/min of starch and 4905 kg/min of water;

(4) and (4) feeding the crude concentrated solution in the step (3) into a main separation centrifuge to obtain concentrated starch milk of the underflow and gluten liquid of the overflow. Wherein, the concentrated starch milk of the underflow contains 983 kg/min of starch and 2091 kg/min of water; the top flow of the gluten liquid contains 8.85 kg/min of starch and 2951 kg/min of water;

(5) the gluten liquid in step 4 is further concentrated, and simultaneously process water is generated; wherein the process water amount is 2868 kg/min;

(6) and 4, refining the concentrated starch milk in the step 4 in a washing and refining system to obtain the refined starch milk. The refined starch milk contains 772 kilograms of starch per minute and 1118 kilograms of water per minute.

Comparative example 2

(1) A fine grinding fluid was obtained by the same conditions as in example 2;

(2) the ground liquid enters a fiber washing and screening system for washing and screening to obtain slurry under the screen; wherein the slurry contains 426 kg/min of starch and 3690 kg/min of water;

(3) and (3) mixing the thick slurry of the separating screen I with the thin slurry in the step (2), and then feeding the mixture into a pre-concentration centrifugal machine to obtain concentration, and generating process water and a crude concentrated solution. Wherein, the feed of the pre-concentration centrifuge contains 901 kg/min of starch and 5142 kg/min of water; the process water amount is 1819 kg/min; the crude concentrate contained 1046 kg/min of starch and 5224 kg/min of water.

(4) And (4) feeding the crude concentrated solution in the step (3) into a main separation centrifuge to obtain concentrated starch milk of the underflow and gluten liquid of the overflow. Wherein, the concentrated starch milk of the underflow contains 1046 kg/min of starch and 2224 kg/min of water; the top flow of the gluten liquid contains 11 kg/min of starch and 3146 kg/min of water;

(5) the gluten liquid in step 4 is further concentrated, and simultaneously process water is generated; wherein the process water amount is 3058 kg/min;

(6) and 4, refining the concentrated starch milk in the step 4 in a washing and refining system to obtain the refined starch milk. The refined starch milk contains 822 kg/min of starch and 1189 kg/min of water.

Comparative example 3

(1) A fine grinding fluid was obtained by the same conditions as in example 3;

(2) the ground liquid enters a fiber washing and screening system for washing and screening to obtain slurry under the screen; wherein the slurry contains 435 kg/min of starch and 3690 kg/min of water;

(3) and (3) mixing the thick slurry of the separating screen I with the thin slurry in the step (2), and then feeding the mixture into a pre-concentration centrifugal machine to obtain concentration, and generating process water and a crude concentrated solution. Wherein, the feed of the pre-concentration centrifugal machine contains 898 kg/min of starch and 5172 kg/min of water; the process water amount is 1860 kg/min; the crude concentrated solution contains 1043 kg/min of starch and 5214 kg/min of water;

(4) and (4) feeding the crude concentrated solution in the step (3) into a main separation centrifuge to obtain concentrated starch milk of the underflow and gluten liquid of the overflow. Wherein, the concentrated starch milk of the underflow contains 1047 kg/min of starch and 2225 kg/min of water; the gluten liquid of the top flow contains 8 kg/min of starch and 3135 kg/min of water;

(5) the gluten liquid in step 4 is further concentrated, and simultaneously process water is generated; wherein the process water amount is 3047 kg/min;

(6) and 4, refining the concentrated starch milk in the step 4 in a washing and refining system to obtain the refined starch milk. The refined starch milk contains 823 kg/min of starch and 1190 kg/min of water.

Comparative example 4

(1) A fine grinding fluid was obtained by the same conditions as in example 4;

(2) the ground liquid enters a fiber washing and screening system for washing and screening to obtain slurry under the screen; wherein the slurry comprises 441 kg/min of starch and 3789 kg/min of water;

(3) and (3) mixing the thick slurry of the separating screen I with the thin slurry in the step (2), and then feeding the mixture into a pre-concentration centrifugal machine to obtain concentration, and generating process water and a crude concentrated solution. Wherein, the feed of the pre-concentration centrifuge contains 829 kg/min of starch and 4844 kg/min of water; the process water amount is 1786 kg/min; the crude concentrated solution contains 963 kg/min of starch and 4811 kg/min of water;

(4) and (4) feeding the crude concentrated solution in the step (3) into a main separation centrifuge to obtain concentrated starch milk of the underflow and gluten liquid of the overflow. Wherein, the concentrated starch milk of the bottom flow contains 964 kg/min of starch and 2050 kg/min of water; the top flow of the gluten liquid contains 9 kg/min of starch and 2895 kg/min of water;

(5) the gluten liquid in step 4 is further concentrated, and simultaneously process water is generated; wherein, the process water amount is 2814 kg/min;

(6) and 4, refining the concentrated starch milk in the step 4 in a washing and refining system to obtain the refined starch milk. The refined starch milk contains 758 kg/min starch and 1096 kg/min water.

Comparative example 5

(1) A fine grinding fluid was obtained by the same conditions as in example 6;

(2) the ground liquid enters a fiber washing and screening system for washing and screening to obtain slurry under the screen; wherein the slurry contains 435 kg/min of starch and 3690 kg/min of water;

(3) and (3) mixing the thick slurry of the separating screen I with the thin slurry in the step (2), and then feeding the mixture into a pre-concentration centrifugal machine to obtain concentration, and generating process water and a crude concentrated solution. Wherein, the feed of the pre-concentration centrifugal machine contains 898 kg/min of starch and 5172 kg/min of water; the process water amount is 1860 kg/min; the crude concentrated solution contains 1043 kg/min of starch and 5214 kg/min of water;

(4) and (4) feeding the crude concentrated solution in the step (3) into a main separation centrifuge to obtain concentrated starch milk of the underflow and gluten liquid of the overflow. Wherein, the concentrated starch milk of the underflow contains 1047 kg/min of starch and 2225 kg/min of water; the top flow of the gluten liquid contains 7.8 kg/min of starch and 3135 kg/min of water;

(5) the gluten liquid in step 4 is further concentrated, and simultaneously process water is generated; wherein the process water amount is 3047 kg/min;

(6) and 4, refining the concentrated starch milk in the step 4 in a washing and refining system to obtain the refined starch milk. The refined starch milk contains 823 kg/min of starch and 1190 kg/min of water.

As can be seen from the comparison of the material balance (Table 2), the amount of starch fed into the preconcentration centrifuge is reduced by 429-821 kg/min (26-49 tons/h) and reduced by 50.8% -91.4% by using the primary concentration compared with the conventional dalton process; the water inflow is reduced by 510-1336 kg/min (31-80 tons/h), and reduced by 10.5% -25.8%; the amount of the starch milk is reduced by 939-2156 kg/min (56-129 tons/h), and the reduced amount is 16.5% -35.5%. The feeding starch amount of the main centrifugal machine is reduced by 398-785 kg/min (24-47 tons/h), the reduced conversion is 40.5% -75.2%, the water inflow is reduced by 618-2003 kg/min (37-120 tons/h), and the reduced conversion is 12.6% -38.4%; the starch milk is reduced by 1016-2788 kg/min (61-167 tons/h), and the reduced conversion is reduced by 17-45%. Thereby greatly reducing the operation load of the pre-concentration and the main centrifugal machine. Correspondingly, compared with the traditional dalton process, the power energy of the pre-concentration centrifuge of the corn wet processing process comprising the primary concentration process is reduced by about 33-71%, and the power energy of the main centrifuge is reduced by 16-40%.

For a conventional dalton process with a capacity of 2000 tons/day, the pre-concentration, main separation and gluten concentration sections are typically configured with 2 centrifuges each. However, since the primary concentration process can greatly save the power energy of the pre-concentration centrifuge and the main separation section, even one centrifuge can be saved in the main separation section, which also greatly saves the cost of investment, operation and maintenance (table 3).

TABLE 3 comparison of conventional Dalton Process and Primary concentration Process Equipment configurations

Device configuration	Preconcentration centrifuge	Main centrifuge	Gluten concentration centrifuge
				Traditional process for making daltons	2 table	2 table	2 table
Primary concentration process	2 table	1 table	2 table

In addition, as can be seen from fig. 3, the reduction of the centrifuge load causes the reduction of the dry matter content of the process water of the centrifuge top flow, especially the concentrated centrifuge top flow (the reduction refers to that of each embodiment relative to the comparative example of the corresponding relation), so that the process water is purified, the quality of the process water is improved, the acid making and soaking processes are effectively improved, the indexes (soluble matter content, fig. 4) of the soaked corn are improved, and the optimization and progress of the whole process are realized.