Method and related equipment for deep processing of corn by pressure infusion

Abstract

The present application relates to a method for deep processing of corn by using pressurized soaking method to prepare dextrin, syrup and / or sugar, and co-production of starch and by-product of germ, protein and fiber, which comprises soaking and crushing, removing germ, curved sieve separation and 12-stage washing, filter cake deslurry, liquefaction, dextrin preparation or saccharification, so as to improve the efficiency and environmental protection of corn deep processing. The process not only improves the yield of starch, germ and fiber, but also eliminates the by-product of corn syrup and sewage discharge. The process flow and new equipment of the present application can effectively reduce investment, land occupation and labor, promote the transformation of corn deep processing to low carbon and green, and meet the market demand for high-quality products.

Description

Technical Field

[0001] This invention relates to the field of corn deep processing, and particularly to a method for deep processing corn using a pressure soaking method to prepare dextrin, syrup and / or sugar, and co-produce starch, wherein germ, protein and corn bran (i.e. corn fiber) are also produced. Background Technology

[0002] Corn is the primary raw material used in the industrial production of starch, dextrin, syrup, or sugar. After purification using well-known industry processes, corn is processed using traditional wet corn processing techniques, including soaking in sulfurous acid, degerming, peeling, starch washing, refining, and drying to produce starch. Alternatively, starch milk can be further liquefied to produce dextrin, or even further saccharified to produce syrup or sugar. Prolonged soaking of corn in sulfurous acid not only converts 2-4% of the high-value protein and 2-3% of the starch into low-value corn steep liquor (Note: Corn steep liquor is a technical term in the wet milling process of corn, referring to the process of soaking corn in sulfurous acid solution, separating the soaked corn, and using the remaining soaking liquid as a product for industrial sale or spraying onto fibers for sale as spray-dried fiber), but also requires steam to concentrate the corn steep liquor before spraying it onto fibers for sale as low-value spray-dried fiber. The production process also generates large amounts of SO2 "odorous gas," polluting the environment. Furthermore, the process requires the use of multiple expensive centrifuges to pre-concentrate the starch slurry, separate and concentrate the protein, etc., to produce qualified commercial starch, or to further liquefy it to produce dextrin, or to further saccharify it to produce sugar or syrup. The former pollutes the environment and increases additional steam consumption; the latter increases additional investment and energy consumption. To reduce or eliminate the use of SO2 soaking and expensive centrifuges, scientists and engineers have conducted numerous beneficial explorations.

[0003] CN101372702A discloses a method for producing starch by soaking corn in sulfurous acid using enzymes instead of sulfurous acid. The method is characterized by: 1. Pre-treatment before soaking: Selecting plump corn kernels free from insect damage and mold, washing them three times with water, draining, and soaking overnight before placing them in a reaction vessel; 2. Soaking: Adding drinking water, 450-1350 IU / g corn protease, and 15-80 IU / g corn cellulase at a corn mass ratio of 1-3 / 1; 3. Pressurization: Connecting compressed air to pressurize to 0.1-0.5 MPa, heating the reaction vessel jacket with steam at 30-60℃ for 10-20 hours. This method uses protease and cellulase instead of sulfurous acid, solving the waste gas problem. However, the use of protease and cellulase increases costs. Furthermore, protease and cellulase convert high-value proteins and starches into water-soluble proteins and sugars, which enter the soaking solution system, becoming low-value corn syrup. The corn syrup still requires steam concentration to produce sprayed fiber.

[0004] The second method involves producing sugar or syrup using a semi-dry corn process. CN115807136A discloses a semi-dry corn germ and bran extraction process for producing low-fat grits and converting them into glucose syrup. The process includes the following steps: Step 1: Conditioning and Moistening: After cleaning, the corn is fed into a paddle-type steam homogenizer. 1-2% steam is added per ton of corn at a pressure of 0.4 MPa, along with 1% room temperature water. The steam and water are controlled by an intelligent moisture meter. After homogenization, the corn is fed into a conditioning chamber. After 4 hours of conditioning, the germ should be flexible and the bran and endosperm should be easily separated. Step 2: Kneading and Degerming: The conditioned corn from Step 1... The corn is fed into a rubbing and degerming machine for rubbing and degerming, breaking the corn into four, six, or eight pieces to ensure the germ remains intact and unbroken, and removing more than 70% of the seed coat. Step 3: Sieving and Grading: The material from Step 2 is fed into a high-precision grading sieve for sieving. Based on particle density, the material is graded into eight categories: 4 mesh (over), 4-6 mesh, 6-8 mesh, 8-12 mesh, 12-24 mesh, 24-40 mesh, 40-60 mesh, and 60 mesh (under). Step 4: Peeling: The eight materials obtained in Step 3 are fed into a peeling machine, where graded airflow and peeling are used to remove the corn husks. Step 5: Material Separation: The material from Step 4... Eight materials, including two materials of 4-6 mesh and 6-8 mesh, are selected by a germ separator to separate the raw germ and raw endosperm. The raw germ is then polished by a rubbing machine and color sorted to obtain pure germ. The raw endosperm is also color sorted to obtain high-purity endosperm, thus purifying both the germ and endosperm. Step Six: Endosperm Crushing: The endosperm of different particle sizes obtained in Step Five is processed by a pelletizer, a high-square flat screen, and a compound purifier. Through pelletizing, sieving, purifying, and selecting, some impurities and broken germ are removed to obtain purified endosperm. Step Seven: Endosperm Purification: The endosperm of different particle sizes obtained in Steps Five and Six is ​​further refined by a combination of a skin suction machine and a color sorter to remove impurities. Step 7: Grinding and pulverizing. The pure endosperm obtained in Step 8 is ground into 40-mesh corn flour by four consecutive grinding stages in a roller mill. Then, the flour is removed by a magnetic separator and a metal detector to remove microparticle metals. Step 9: Blending and preparation. The material obtained in Step 8 is mixed with drinking water at a mass ratio of 1:2.3 to form a slurry. The slurry is then transferred to a colloid mill for further grinding. After saccharification, liquefaction, and protein extraction, glucose syrup is finally produced. This method does not have a starch and protein separation process and cannot produce qualified starch. In addition, the starch content is high due to the high binding of germ and fiber, resulting in low overall economic benefits.

[0005] Thirdly, steam explosion is used to replace the corn soaking process. CN101607218A discloses the use of steam explosion technology to separate corn germ, endosperm and seed coat: 1. Soak corn to 30% water content; 2. The steam explosion pressure is 1.0-1.5MPa and the time is 3-6min. This method uses 1.0-1.5MPa steam to act on corn, which denatures the germ and gelatinizes the endosperm. Special equipment needs to be developed to further process the denatured germ and gelatinized endosperm.

[0006] Fourthly, dry corn sugar production. CN104630310A discloses a production method for glucose from crushed corn, characterized by the following steps: 1) Impurity removal: removing impurities from crushed corn; 2) Crushing: crushing corn into corn flour particles with a particle size of 100% passing through a 60-mesh sieve; 3) Slurry preparation: adding corn flour particles into a slurry preparation tank, adding evaporating condensate and stirring to form a corn starch slurry with a dry matter concentration of 40%; 4) Sand removal: removing fine sand and gravel from the slurry; 5) Slurry preparation: adding evaporating condensate to make the dry matter content of the slurry reach 30%, and adding NaCO3 to adjust the pH value to 5. -7, and add liquefying enzyme at a ratio of 0.5-0.8‰ of the slurry weight; 6) Jet liquefaction: Pump the material in the starch slurry tank into the jet liquefaction unit. The jet liquefaction temperature is controlled at 108℃. The liquefied material enters the retention tube and the liquefaction column in sequence, and the liquefaction time is maintained at 95℃ for 3 hours. The DE value of the liquefied liquid is controlled at 10-15; 7) Filtration: The qualified liquefied liquid after liquefaction is filtered through a plate and frame filter press. The filtered liquefied liquid enters the saccharification tank for saccharification; 8) Saccharification: Adjust the pH of the liquid to 4.2-4.5 with hydrochloric acid, and at the same time quickly cool it to 62℃. ℃, then add saccharifying enzyme for saccharification. After saccharification time is greater than 40 hours, when no dextrin is detected and the DE value is greater than 95%, saccharification is terminated. The pH of the material is adjusted to 4.8-5.5 and then it enters the filtration tank; 9) Filtration: Before filtration, the material temperature is reduced to below 60℃. After the plate and frame filter is pre-coated with diatomaceous earth, it is filtered to remove the denatured and flocculated protein solids contained in the material. The material enters the decolorization tank; 10) Decolorization: The sugar solution is pumped into the plate and frame filter that has been pre-coated with activated carbon for decolorization. During decolorization, the valve is opened so that the decolorized sugar solution enters the ion exchange process; 11) Ion exchange The decolorized sugar solution is first pumped into the regenerated cation column, with the flow rate controlled to be approximately twice the resin volume per hour. After exiting the cation column, the sugar solution enters the anion column, where the conductivity is controlled to be less than 50 μS / cm and the pH between 4.5 and 6.0. This removes ionic impurities and pigments from the sugar solution, and the qualified solution enters the evaporation feed tank. 12) Evaporation and Concentration: The ionized sugar solution is pumped into a 5-effect negative pressure evaporation system for concentration, with the concentration controlled at 70%-75%. The qualified sugar solution is then stored in the finished product tank. This method cannot produce qualified starch, nor does it produce germ, protein, or fiber, making its economic benefits questionable.

[0007] Fifth, optimize the starch production process and reduce the amount of centrifuges used. CN 113621083B discloses a wet milling process and a primary concentration process for corn starch, characterized by: (1) after the corn has completed the soaking and crushing process, it is separated by a separating screen I to obtain a concentrated slurry of separating screen I and a material on the screen of separating screen I; (2) the material on the screen of separating screen I is fed into a fine mill for fine crushing to obtain a fine milling liquid; (3) the fine milling liquid is separated by a separating screen II to obtain a concentrated slurry of separating screen II and a material on the screen of separating screen II; (4) the material on the screen of separating screen II is fed into a fiber washing and screening system to obtain a thin slurry a and a material on the screen used for fiber extraction; optionally, at least a portion of the thin slurry a is diverted into thin slurry a1 and a... (5) The concentrated slurry from separating screen I, the concentrated slurry from separating screen II, and optionally the thin slurry a1 are fed into a hydrocyclone for further concentration to obtain underflow concentrated starch milk I and overflow thin slurry b; (6) The thin slurry a, thin slurry b, and optionally the thin slurry a2 are fed into a pre-concentration centrifuge to obtain crude concentrate and generate process water; (7) The crude concentrate is fed into a main separation centrifuge to obtain underflow concentrated starch milk II and topflow gluten liquid; (8) The gluten liquid is further concentrated to obtain concentrated gluten liquid through gluten concentration, while generating process water; and (9) The concentrated starch milk I and II are fed into a washing and refining system for refining to obtain refined starch milk. This method separates the crude concentrate and feeds it directly into the main separation centrifuge, reducing the load on the concentration centrifuge, but it still cannot get rid of the centrifuge. In addition, the SO2 soaking method is unremarkable.

[0008] Therefore, it is necessary to optimize the traditional corn wet milling process across the entire system to provide a new method for producing dextrin, sugar (or syrup), and starch simultaneously, while also producing germ, protein, and fiber. This method does not require traditional sulfurous acid soaking, does not produce corn steep liquor as a byproduct, and addresses environmental concerns regarding waste gas and wastewater. Furthermore, it replaces the first and second milling processes, reducing the amount of starch adhering to the germ and fiber, and further improving the quality of the germ and fiber. It also eliminates the need for centrifuge pre-concentration of starch slurry, separation of starch, and concentration of protein, allowing for a more rational allocation of starch and sugar (syrup) production capacity, and further reducing construction investment and operating costs. Summary of the Invention

[0009] The purpose of this invention is to provide a method for deep processing corn using a pressure soaking method, particularly for preparing dextrin, syrup, and / or sugar, and co-producing starch. This method replaces the traditional sulfurous acid soaking process with pressure soaking, allowing corn to rapidly absorb water and expand without damaging the germ and endosperm quality or generating wastewater or exhaust gas, achieving the same requirements as wet milling. In this method, the jet crushing device and process of this invention replace the existing toothed mill and process, releasing 100% of the germ, 24-40% of the free starch, and over 78% of the corn bran (i.e., corn fiber), resulting in a lower amount of bound starch in the germ and corn fiber. Furthermore, the underflow (free starch slurry) from the cyclone-selected germ is separated by a gravity sieve; the material remaining on the sieve is further pulverized and the fiber separated before being used to prepare dextrin and sugar (or syrup); the material passing through the sieve undergoes a 12-stage starch washing process, and after refining and drying, qualified starch is obtained. This method can also simultaneously produce germ, protein, and fiber. The method of this invention has significant practical implications for energy saving, cost reduction, quality improvement, and efficiency enhancement compared to traditional methods in the corn deep processing industry.

[0010] Specifically, the present invention relates to a method for deep processing of corn using a pressure soaking method, particularly for preparing dextrin, syrup and / or sugar, and co-producing starch, as well as simultaneously producing germ, protein and fiber, comprising the following steps:

[0011] (1) Soaking and crushing: Corn raw materials, water and optional chemical additives are continuously or in batches added to a pressure soaking reactor, where a soaking reaction is carried out. Then, the corn is continuously or intermittently crushed by a jet crushing device to obtain a water-containing corn slurry A.

[0012] (2) Remove the germ from the corn slurry A to obtain corn slurry B and germ;

[0013] (3) The corn slurry B is fed into a gravity curved screen S1. The material on the S1 screen is finely ground and further pulverized. Then, the fiber is removed by a pressure curved screen S2 to obtain corn slurry C and corn fiber. The material under the S1 screen is fed into a starch 12-stage washing process. The top stream of the 12-stage washing process is mixed with the corn slurry C to obtain corn slurry D. The corn slurry D is filtered and washed simultaneously to obtain filter cake E and process water. The bottom stream of the 12-stage washing process is refined starch slurry (sometimes referred to as "starch milk" in this application) is dehydrated and dried to obtain starch.

[0014] (4) Filter cake E is slurryed and liquefied. (i) The solids in the liquefied liquid are separated. The solids are further processed to obtain protein. The liquefied liquid after solids separation is dried to obtain dextrin. And / or the liquefied liquid after solids separation is further saccharified to obtain syrup. Or (ii) The liquefied liquid is first further saccharified to obtain saccharified liquid. The solids in the saccharified liquid are then separated to obtain syrup. The solids are further processed to obtain protein.

[0015] (5) Optionally, the syrup in step (4) is further crystallized to obtain sugar.

[0016] In one embodiment of the present invention, step (1) of the above method can be carried out as follows: corn raw material, water and optional chemical additives are continuously or batch-wise added to a soaking reactor; in the soaking reactor, the reaction is carried out for 0.5-15 hours at a reaction temperature of 20-100°C and a gauge pressure of 0.1 MPa or higher to obtain corn with a water content greater than or equal to 35% by weight; the soaking reactor is maintained at the gauge pressure or a pressure greater than the gauge pressure; and then the corn with water content is rapidly crushed through a jet pipe continuously or batch-wise to obtain corn slurry A.

[0017] In this invention, the moisture content of the corn raw material can be, for example, 9-46% by weight, such as 10-44% by weight.

[0018] In this invention, the moisture content of the water-containing corn is preferably greater than or equal to 38% by weight, more preferably greater than or equal to 40% by weight.

[0019] In one embodiment of the present invention, the corn raw material is first washed with water to remove impurities such as dust from the surface of the corn raw material, and optionally shriveled kernels and corn debris of different sizes, such as corn cobs, corn stalks, stones, etc., as well as possibly gloves, bricks, iron blocks, etc., are separated and removed. Preferably, the water is drained and the drained corn is added to a pressure soaking reactor.

[0020] In one embodiment of the present invention, the corn slurry A obtained comprises germ, fiber, starch and endosperm.

[0021] In one embodiment of the present invention, the corn slurry A contains a release germ with a release rate of 100%, a release fiber with a release rate of more than 78%, and a free starch with a release rate of 24-40%, preferably 24-35%.

[0022] In one embodiment of the present invention, the pressure soaking reactor is a kettle soaking reactor or a tubular soaking reactor, such as a continuous tubular soaking reactor. For example, the pressure soaking reactor includes one or more pressure vessels or reactors (kettles or towers) such as pressure kettles, pressure tanks, continuous cookers, tubular reactors, pressure screw conveyors, towers, steam balls, autoclaves, decomposition pots, and vulcanizing tanks, which can be used individually, in series, or in parallel.

[0023] In one embodiment of the present invention, the pressure soaking reactor is a batch soaking reactor, wherein corn raw material is metered and added to the soaking reactor in batches by a screw feeder, and discharged in batches by the jet crushing system of the present invention. The soaking reactor is equipped with a distributor, an external heat exchanger (which is used to heat the corn and soaking water to the temperature required by the process) and / or an external hot water tank (which provides water for soaking the corn and simultaneously brings the material in the soaking reactor to the temperature required by the process). The soaking reactor is also connected to an external air source or water source (which is used to pressurize the soaking reactor to the pressure required by the process), and the temperature and pressure of the reactor are precisely controlled by a DCS system.

[0024] In one embodiment of the present invention, the pressure soaking reactor is a continuous tubular reactor, wherein the reactor is metered by a screw feeder and continuously fed with corn raw materials via a rotary valve, and continuously discharged through an external jet crushing system of the present invention via another rotary valve. The soaking reactor is equipped with a distributor, an external heat exchanger (for heating the corn and soaking water to the required process temperature) and / or an external hot water tank (which provides water for soaking the corn while simultaneously bringing the material in the soaking reactor to the required process temperature). The soaking reactor is also externally connected to a gas source or a water source (for pressurizing the soaking reactor to the required process pressure), and the temperature and pressure of the reactor are precisely controlled by a DCS system.

[0025] The water is selected, for example, from drinking water, deionized water, or recycled process water. Preferably, the amount of water added is 30-300% by weight based on the dry weight of corn, more preferably 50-200% by weight, even more preferably 60-150% by weight, and even more preferably 65-120% by weight, for example 65% by weight, 70% by weight, 80% by weight, 90% by weight, and 100% by weight.

[0026] Preferably, in the pressure soaking reactor, the pressure soaking reaction temperature is 40-75°C, more preferably 45-70°C, for example 50°C, 60°C, and 65°C. Preferably, in the pressure soaking reactor, the gauge pressure of the pressure soaking reaction is 0.1-10 MPa, more preferably 0.5-8 MPa, and even more preferably 0.5-6 MPa, for example 1 MPa, 1.2 MPa, 1.5 MPa, 2 MPa, and 6 MPa.

[0027] Preferably, the soaking reaction time is 0.5-15 hours, more preferably 0.5-10 hours, for example 1, 2, 3, 4, 5, 6 and 8 hours.

[0028] After soaking is completed, the pressure soaking reactor is maintained at or above the gauge pressure during the soaking reaction, for example, 0.1-15 MPa, more preferably 0.5-10 MPa, even more preferably 0.5-8 MPa, and even more preferably 1-6 MPa.

[0029] The linear velocity of the water-containing corn rapidly crushed by the jet pipe should be sufficient to cause sufficient crushing of the soaked corn to achieve the effect described in this invention. For example, the linear velocity should be above 10 m / s, especially 50-120 m / s, preferably 55-110 m / s.

[0030] In one embodiment, a suitable gas or water, such as air, nitrogen, oxygen and / or water, that does not affect the reaction is introduced into the pressure soaking reactor to increase the pressure of the reactor, while water vapor is not a suitable gas.

[0031] In one embodiment, in addition to corn and water, a chemical additive is added to the pressure soaking reactor. The chemical additive can be an acid, alkali (containing Lewis acids or alkalis), or enzyme, such as citric acid, acetic acid, oxalic acid, sulfuric acid, hydrochloric acid, sodium sulfite, etc. Preferably, the amount of the chemical additive is 0-10% by weight based on the dry weight of the corn, more preferably 0-1.5% by weight, and even more preferably 0-1% by weight, for example, 0% (neutral soaking), 0.5% by weight, and 1% by weight.

[0032] In one embodiment, the pressurized soaking process is as follows: the mass ratio of purified corn to water is 1:0.2-3; the temperature is 40-70℃; the pressure is above 0.1MPa; and the soaking time is 0.5-10 hours.

[0033] For example, one embodiment of step (1) of the corn processing method of the present invention includes the following steps:

[0034] (a) Wash the corn raw material with water to remove the dust on the surface of the corn, separate and remove the shriveled kernels and corn impurities of different sizes, and drain the water;

[0035] (b) Weighing step (a) The treated corn and 50-200% by weight of water based on the dry weight of the corn are continuously or in batches added to a pressure soaking reactor. In the pressure soaking reactor, the corn is soaked and reacted at 20-75°C and 0.1-10 MPa for 0.5-9 hours. The corn is continuously or intermittently crushed into a receiving tank by the jet crushing device of the present invention.

[0036] In this invention, the jet crushing process uses high-pressure gas or water to provide kinetic energy, accelerating corn to a certain linear velocity and jetting it into a receiving tank (e.g., an atmospheric pressure receiving tank) to obtain crushed corn slurry A. The jet crushing process of this invention can remove binding starch from germ and fiber to the maximum extent, releasing free starch without damaging the corn starch and its protein protective network; the protein content of the free starch slurry B can be controlled to below 3.0% by weight, eliminating the need for expensive disc centrifuges and allowing for direct refining of starch using a twelve-stage washing process to obtain the desired starch.

[0037] On the other hand, the present invention provides a soaking and crushing device for deep processing of corn, particularly for implementing step (1) of the deep processing corn method described above. This device includes, for example, a corn feeder, a pressure soaking reactor, a gas compressor and / or a water pump, a venturi tube, a water tank, and a jet pipe. The gas compressor and / or water pump, the corn feeder, and the water tank are connected to the soaking reactor, and the venturi tube and the jet pipe are connected sequentially from the outlet of the pressure soaking reactor. The device also includes the jet crushing apparatus used.

[0038] The corn raw material feeder mentioned above is, for example, a screw feeder, a belt scale, a lifting hopper, a rotary valve, etc.

[0039] The pressure soaking reactor is, for example, a kettle soaking reactor or a tubular soaking reactor, such as a continuous tubular soaking reactor. For example, the pressure soaking reactor includes one or more pressure vessels or reactors (kettles or towers) such as pressure kettles, pressure tanks, continuous cookers, tubular reactors, pressure screw conveyors, towers, steam balls, autoclaves, decomposition pots, and vulcanizing tanks, which can be used individually, in series, or in parallel.

[0040] A gas compressor and / or water pump are used to increase the pressure in the pressure soaking reactor and maintain it at a certain pressure level. Depending on the specific reaction conditions, either a gas compressor or a water pump can be used to increase the pressure. The gas compressor and water pump can be used individually, or in series or parallel.

[0041] The function of the venturi tube is to provide a channel for the water pump and / or gas compressor to deliver the medium into the injection pipe to increase the kinetic energy of the corn during jet crushing, and to draw the corn into the injection pipe through the pressure difference for jet crushing.

[0042] The water supply tank provides the water used for soaking in the soaking reactor. Preferably, the water supply tank is a hot water supply tank to provide the appropriate temperature required for soaking.

[0043] The injection tube is the channel through which the corn is ejected. Preferably, the injection tube is further narrowed in diameter compared to the Venturi tube to increase the linear velocity and kinetic energy of the corn, thereby increasing the corn breakage rate. Therefore, preferably, the diameter of the injection tube is smaller than that of the Venturi tube.

[0044] The pressure soaking reactor of the present invention may be equipped with a bottom valve or a rotary valve to control the discharge of materials.

[0045] The slurry exiting the jet pipe can be injected into a receiving tank, such as an atmospheric pressure receiving tank.

[0046] In one embodiment of the invention, reference is also made to the appendix. Figure 2 The soaking and crushing equipment of this invention includes a screw feeder, a pressure soaking tank, a gas compressor (or a water pump), a venturi tube, a hot water tank, a jet pipe, and a receiving tank. Specifically, the screw feeder precisely delivers corn raw materials to the pressure soaking tank. A pump metered and delivered hot water from the hot water tank to the pressure soaking tank, and the temperature of the soaking tank is adjusted to the required process temperature. A gas compressor continuously supplies gas (or a pump continuously supplies water), and the pressure of the soaking tank is adjusted to the required process pressure. After soaking for a certain period (e.g., 0.5-10 hours) to control the corn moisture content to the required process level, the gas compressor (or water pump) adjusts the pressure of the pressure soaking tank to the pressure required for jet crushing. The bottom valve of the pressure soaking tank is opened, and the corn and soaking water, driven by the pressure of the pressure soaking tank, are accelerated through the venturi tube and then accelerated to a certain linear velocity through the jet pipe, and sprayed into the atmospheric pressure receiving tank to obtain corn slurry A (which includes crushed corn and released germ and fiber).

[0047] In this invention, the jet crushing can be completed in one step or in multiple steps, provided that the corn crushing rate is 100%, the germ release rate is 100%, and the fiber release rate is above 78%, and the germ damage rate is required to be less than 35%.

[0048] In step (2), germ removal can be performed using a hydrocyclone separator, which is commercially available, preferably with a hydrocyclone feed pressure greater than 0.25 MPa. In one embodiment, germ removal can be performed by further crushing the corn in the corn slurry A obtained in step (1), for example, using a toothed mill, and then separating the germ using a hydrocyclone separator. The resulting germ may contain a small amount of fiber. The obtained germ can be washed and dried to obtain a germ product.

[0049] The 12-stage washing can be performed using a commercially available starch 12-stage washing device.

[0050] The gravity curved screen S1 in this invention can be a commercially available gravity curved screen, which can have a screen gap of 25μm, 50μm, 75μm or 100μm, or any intermediate screen gap.

[0051] The pressure curved screen in this invention can be a pressure curved screen group, for example, it includes a 1-6 stage washing curved screen, a 1 stage separation curved screen and a 1 stage dewatering curved screen.

[0052] The dewatering of refined starch slurry in step (3) of this invention can be carried out using a pressure drum filter or a scraper centrifuge.

[0053] The corn slurry D in step (3) of this invention can be washed and filtered simultaneously using a vacuum drum filter. The corn slurry D can also be filtered and washed using a filter machine, such as a vacuum drum filter, to obtain a filter cake E containing starch and protein.

[0054] The process of separating solids from liquefied liquid (or saccharified liquid) in step (3) of the present invention can be carried out by using a vacuum drum filter (or pressure drum filter or plate and frame filter) to filter and wash the protein, thereby obtaining protein with a sugar (or dextrin) content of less than 3% by weight.

[0055] In step (3), the fine grinding is, for example, needle grinding.

[0056] In step (4), the pH of the liquefied liquid is preferably adjusted to 4.0-4.4, more preferably 4.0-4.2, for saccharification.

[0057] In step (4), the saccharification is carried out, for example, by adding a saccharifying enzyme (e.g., a saccharifying complex enzyme), in an amount of, for example, 0.01-0.07% by weight based on dry corn starch, such as 0.05% by weight. The DE value of the saccharified liquid after saccharification is preferably 95-98, for example, 96.7.

[0058] In one embodiment of the present invention, in step (4), filter cake E is saccharified by adding water to adjust the slurry, adjusting the pH value, adding enzyme to liquefy and saccharify to obtain a saccharified liquid; the saccharified liquid is filtered to obtain syrup and solid filter cake, and the solid filter cake is washed and further processed to obtain protein.

[0059] In one embodiment of the present invention, in step (4), the temperature of the slurry is preferably 60-65°C and the pH is preferably 5.5-6; the liquefaction is carried out, for example, by spraying, and the liquefaction process can be one spray or two sprays, or it can be mild liquefaction at 76-100°C, wherein a liquefying enzyme (e.g., a high-temperature liquefying enzyme) is added, which can be added once or twice, preferably twice, and the amount added is preferably 0.1-0.5 kg / ton of dry corn starch; the DE value of the liquefied liquid is preferably controlled to be 14-18.

[0060] In step (5), the syrup may be further filtered, decolorized, ion-exchanged, and / or concentrated before crystallization to obtain sugar. The sugar is preferably glucose.

[0061] Another object of the present invention is to provide syrups, sugars, starches, dextrins, germs, corn fiber, and / or proteins obtained by the methods of the present invention.

[0062] The method for determining the content in this application is as follows:

[0063] (1) Determination of moisture content of corn after soaking

[0064] Take the soaked corn and wipe off the surface moisture with absorbent paper. Weigh 3-5g of the corn and place it in a METTLERTOLEDO halogen moisture analyzer to quickly determine the moisture content of the corn.

[0065] (2) Determination of free starch content in corn syrup

[0066] Take 2000g of corn slurry B and pass it through a 65μm sieve. Centrifuge the material on the sieve and the material under the sieve separately to remove free water, and weigh them to obtain m1 and m2. Take about 5g of the material on the sieve and the material under the sieve after centrifugation, and place them in a METTLERTOLEDO halogen moisture analyzer to quickly measure the moisture content of the corn, and obtain the moisture content w1 and w2.

[0067] Free starch content = m2*(1-w2) / 《m1*(1-w1)+m2*(1-w2)》

[0068] (3) Determination of protein content in starch

[0069] The protein in starch is decomposed under catalytic heating conditions, and the resulting ammonia combines with sulfuric acid to form ammonium sulfate. Alkaline distillation releases the ammonia, which is then absorbed by boric acid and titrated with a standard sulfuric acid or hydrochloric acid solution. The nitrogen content is calculated based on the amount of acid consumed, multiplied by a conversion factor, and then multiplied by a fixed factor of 6.25 to obtain the protein content.

[0070] (4) Determination of germ binding starch

[0071] a. Pretreatment of germ and starch samples: Take about 20g of wet germ sample separated by a germ hydrocyclone and place it in a 3350μm sieve; take another stainless steel round basin, put 2000ml of water in the basin, and sieve it in the water with a 3350μm sieve to separate the germ, fiber and embryo body. Separate the embryo body connected to the germ and place them separately in petri dishes and dry them in a vacuum oven at 55℃.

[0072] b. Detection of sample: Weigh the dried germ and the peeled starch embryo separately using a 0.01 g balance to obtain W1 and W2 respectively.

[0073] c. Calculation: Germ starch binding rate = W2 / (W1+W2)*100%.

[0074] (5) Determination of fiber-binding starch

[0075] a. Pretreatment of fiber and starch samples: Take about 20g of the initially wet fiber separated by the fiber separation sieve and place it in a 20-mesh sieve; take another stainless steel round basin, put 2000ml of water in the basin, and sieve it in the water with a 20-mesh sieve to separate the fiber from other particles, and obtain the fiber containing the bound starch. Place the fiber on a petri dish and dry it in a vacuum oven at 55℃. Manually peel off the bound starch from the dried fiber to obtain pure fiber and bound starch respectively.

[0076] b. Detection of sample: Weigh the pure fiber and binding starch separately using a 0.01 g balance to obtain W1 and W2 respectively.

[0077] c. Calculation: Fiber-bound starch rate = W2 / (W1+W2)*100%.

[0078] (6) Determination of embryo breakage rate

[0079] a. Germ pretreatment: Take the germ separated by the germ hydrocyclone, wash with clean water to remove the carried fibers, and centrifuge to dehydrate.

[0080] b. Testing: Weigh 10g of pretreated embryos and manually sort the whole embryos and damaged embryos.

[0081] c. Calculation: Germ breakage rate = weight of broken germ / 10 * 100%.

[0082] Features of the present invention

[0083] (1) Replacing the traditional wet-process corn sulfite soaking with pressurized soaking can shorten the soaking time from 36-48 hours to 0.5-15 hours. For example, based on a processing capacity of 500,000 tons of corn per year, the soaking tank volume can be reduced from 10*450m³. 3 It dropped to 3*200m 3 This can save a significant amount of construction costs and land area.

[0084] (2) The soaking of the present invention does not use sulfurous acid, does not produce corn syrup and SO2 odor, and is safe and environmentally friendly.

[0085] (3) The use of spraying process to replace the traditional first and second grinding processes results in the release of less than 3% by weight and 6% by weight of binding starch on germ and fiber, respectively, which is much lower than that of traditional process.

[0086] (4) The present invention produces sugar (or syrup) and starch in parallel without the need for expensive centrifuges, thus saving investment and operating costs.

[0087] (5) Compared with the traditional process, the present invention has a dextrin (if present) yield (DS) of more than 51%; a starch yield (DS) of more than 22%; a sugar yield (DS) of more than 47%; a protein yield (DS) of more than 8%; a pure germ yield (DS) of more than 6.5%; and a fiber yield of less than 10%.

[0088] (6) Compared with the traditional process, the installed capacity of the present invention is reduced by at least 40%, steam by at least 25%, and wastewater by at least 90%. Attached Figure Description

[0089] Appendix Figure 1 A flowchart illustrating one embodiment of the present invention for deep processing of corn using a pressure soaking method.

[0090] Appendix Figure 2 Flowchart of pressurized soaking and jet crushing equipment Detailed Implementation

[0091] Example

[0092] The technical solution of the present invention will be further described below with reference to embodiments. The embodiments of the present invention should not be construed as limiting the present invention. Those skilled in the art will recognize that various modifications, variations, and combinations can be made to the embodiments of the present invention without departing from the scope of protection of the present invention, and such modifications, variations, and combinations are considered to be within the scope of originality.

[0093] Example 1

[0094] Step 1, Corn purification: Wash the corn raw material (containing 10.44% water by weight) with drinking water to remove dust from the surface of the corn, separate the shriveled kernels and large and small corn impurities, and drain the water;

[0095] Step 2, Soaking and Crushing: Weigh 1200 kg of the purified corn from Step 1 and add it to a 2.0 cubic meter high-pressure reactor. Add 800 kg of water and 1.2 kg of commercially available citric acid. Heat to 65°C and pressurize to 1 MPa gauge pressure for 1 hour. Using the jet crushing device of this invention, spray the corn into an atmospheric pressure receiving tank at a linear velocity of 57.1 m / s to obtain corn slurry A. The corn slurry A was measured to have a germ release rate of 100%, a fiber release rate of approximately 80%, and germ-binding starch content of 2.8% by weight and fiber-binding starch content of 4.7% by weight.

[0096] Step 3, cyclone separation of germ: The germ of corn slurry A is removed by a cyclone separator, and the remaining slurry is corn slurry B, in which free starch accounts for 28% by weight of the total corn slurry B and the free starch contains 2.6% by weight of protein; the removed germ is washed, extruded and dried using processes known in the art to obtain the germ product;

[0097] Step 4: Separation of free starch: Corn slurry B is fed into gravity curved screen S1. The material on the screen is further pulverized by fine grinding. It is then washed and separated by pressure curved screen S2 to obtain corn slurry C and corn fiber. The corn fiber is further washed, extruded, and dried to obtain the finished fiber. The material under the gravity curved screen S1 is free starch slurry, which is fed into the starch 12-stage wash. Corn slurry C is mixed with the top flow of the 12-stage wash to obtain corn slurry D. Corn slurry D is fed into a vacuum drum filter for filtration, dehydration, and washing, to obtain filter cake E and process water, respectively. The underflow of the 12-stage wash is refined starch slurry, which is concentrated and dried to obtain the finished starch. The starch contains 0.34% by weight of protein.

[0098] Step 5: Slurry preparation, liquefaction, and saccharification: Mix filter cake E and water to prepare a slurry with a solid content of 38% by weight. Adjust the pH to 5.6-5.8. Add 0.025% by weight of high-temperature liquefaction enzyme (based on the dry weight of corn starch) all at once, and pre-liquefy at 60-65℃ for half an hour. Spray the prepared corn slurry at 108℃ for 15 minutes. Cool to 95℃ and liquefy for another 90 minutes. Control the DE value of the liquefied liquid to 14-18, and the iodine test should be qualified. The DE value of the liquefied liquid was measured to be 16.74, and the iodine test of the free starch in the filter cake was qualified. The pH of the liquefied liquid was adjusted to 4.0-4.2, the temperature was lowered to 63℃, and 0.055% by weight of a saccharifying complex enzyme (based on dry corn starch) was added. Saccharification was carried out for 10 hours to obtain a saccharified liquid with a DE value of 96.7. The sugar solution was filtered through a vacuum drum filter to obtain the sugar solution and protein. The protein was dried to obtain the finished protein product. The sugar solution was concentrated to 70% by weight to obtain the finished liquid sugar, or further crystallized to obtain the finished glucose product. After drying and weighing, the following yields were obtained: starch yield (DS) 26.33%, sugar yield (DS) 49.62%, pure germ yield (DS) 6.78%, protein yield (DS) 8.36%, and white fiber yield (DS) 9.85%.

[0099] Example 2

[0100] Step 1: Clean the corn: Wash the corn raw material (containing 15.15% by weight of water) with drinking water to remove the dust on the surface of the corn, separate the shriveled kernels and corn impurities of different sizes, and drain the water;

[0101] Step 2, Soaking and Crushing: Continuously weigh 400 kg / h of purified corn and 300 kg / h of water from Step 1, and continuously add them to a 2.0 cubic meter high-pressure tubular reactor. Maintain the temperature at 50°C and continuously input air to maintain a gauge pressure of 6 MPa. After a 3-hour reaction period, use the jet crushing device of this invention to continuously spray the corn into an atmospheric pressure receiving tank at a linear velocity of 109 m / s to obtain corn slurry A. Measurements of corn slurry A show that the germ release rate is 100%; the fiber release rate is approximately 82%; the germ-binding starch content is 1.2% by weight, and the fiber-binding starch content is 3.6% by weight.

[0102] Step 3, cyclone separation of germ: The germ of corn slurry A is removed by a cyclone separator, and the remaining slurry is corn slurry B, in which free starch accounts for 26% by weight of the total corn slurry B and the free starch contains 2.9% by weight of protein; the removed germ is washed, extruded and dried using processes known in the art to obtain the germ product;

[0103] Step 4: Separation of free starch: Corn slurry B is fed into gravity curved screen S1. The material on the screen is further pulverized by fine grinding. It is then washed and separated by pressure curved screen S2 to obtain corn slurry C and corn fiber. The corn fiber is further washed, extruded, and dried to obtain finished fiber. The material under the gravity curved screen S1 is free starch slurry, which is fed into the starch 12-stage wash. Corn slurry C is mixed with the top flow of the 12-stage wash to obtain corn slurry D. Corn slurry D is fed into a vacuum drum filter for filtration, dehydration, and washing, yielding filter cake E and process water respectively. The underflow of the 12-stage wash is refined starch slurry, which is concentrated and dried to obtain finished starch containing 0.33% by weight of protein.

[0104] Step 5: Slurry preparation, liquefaction, and saccharification: Mix filter cake E and water to prepare a slurry with a solid content of 37% by weight. Adjust the pH to 5.6-5.8. Add 0.021% by weight of high-temperature liquefaction enzyme (based on the dry weight of corn starch) all at once, and pre-liquefy at 60-65℃ for half an hour. Spray the prepared corn slurry at 108℃ for 15 minutes to liquefy. Cool to 95℃ and liquefy for another 90 minutes. Control the DE value of the liquefied liquid to 14-18, and the iodine test should be qualified. The DE value of the liquefied liquid was measured to be 17.63, and the iodine test of the free starch in the filter cake was qualified. The pH of the liquefied liquid was adjusted to 4.0-4.2, the temperature was lowered to 63℃, and 0.060% by weight of a saccharification complex enzyme (based on dry corn starch) was added. Saccharification was carried out for 10 hours to obtain a saccharified liquid with a DE value of 97.1. The sugar solution was filtered through a vacuum drum filter to obtain the sugar solution and protein. The protein was dried to obtain the finished protein product. The sugar solution was concentrated to 70% by weight to obtain the finished liquid sugar, or further crystallized to obtain the finished glucose product. After drying and weighing, the following yields were obtained: starch yield (DS) 24.55%, sugar yield (DS) 51.48%, pure germ yield (DS) 6.83%, protein yield (DS) 8.52%, and white fiber yield (DS) 9.56%.

[0105] Example 3

[0106] Step 1: Clean the corn: Wash the corn raw material (containing 15.15% by weight of water) with drinking water to remove the dust on the surface of the corn, separate the shriveled kernels and corn impurities of different sizes, and drain the water;

[0107] Step 2, Soaking and Crushing: Continuously weigh 400 kg / h of purified corn and 500 kg / h of water from Step 1, and continuously add them to a 2.0 cubic meter high-pressure tubular reactor. Maintain the temperature at 60°C, continuously pump water in, and maintain a gauge pressure of 2.0 MPa. After a 3-hour reaction period, use the jet crushing device of this invention to continuously spray the corn into an atmospheric pressure receiving tank at a linear velocity of approximately 63 m / s to obtain corn slurry A. The corn slurry A was measured to have a germ release rate of 100%, a fiber release rate of 78%, and germ-binding starch content of 1.8 wt% and fiber-binding starch content of 3.8 wt%.

[0108] Step 3, cyclone separation of germ: The germ of corn slurry A is removed by a cyclone separator, and the remaining slurry is corn slurry B, in which free starch accounts for 24% by weight of the total corn slurry B and the free starch contains 2.7% by weight of protein; the removed germ is washed, extruded and dried using a process known in the art to obtain the germ product;

[0109] Step 4: Separation of free starch: Corn slurry B is fed into gravity curved screen S1. The material on the screen is further pulverized by fine grinding. It is then washed and separated by pressure curved screen S2 to obtain corn slurry C and corn fiber. The corn fiber is further washed, extruded, and dried to obtain the finished fiber. The material under the gravity curved screen S1 is free starch slurry, which is fed into the starch 12-stage wash. Corn slurry C is mixed with the top flow of the 12-stage wash to obtain corn slurry D. Corn slurry D is fed into a vacuum drum filter for filtration, dehydration, and washing to obtain filter cake E and process water, respectively. The underflow of the 12-stage wash is refined starch slurry, which is concentrated and dried to obtain the finished starch. The starch contains 0.34% protein by weight.

[0110] Step 5: Slurry preparation, liquefaction, and preparation of dextrin and protein: Mix filter cake E and water to prepare a slurry with a solid content of 37% by weight. Adjust the pH to 5.6-5.8. Add 0.019% by weight of high-temperature liquefaction enzyme (based on the dry weight of corn starch) all at once, and stir and pre-liquefy at 60-65℃ for half an hour. Spray the prepared corn slurry at 108℃ for 15 minutes. Cool to 95℃ and liquefy for another 90 minutes. Control the DE value of the liquefied liquid to 14-18, and the iodine test should be qualified. The DE value of the liquefied liquid is measured to be 16.73, and the iodine test of the free starch in the filter cake is qualified. Filter the liquefied liquid through a vacuum drum filter to obtain protein and the filtered liquefied liquid. Refine and dry the protein and the filtered liquefied liquid separately to obtain the finished protein and finished dextrin. The following yields were obtained by drying and weighing: starch yield (DS) 22.25%, dextrin yield (DS) 51.19%, pure germ yield (DS) 6.87%, protein yield (DS) 8.33%, and white fiber yield (DS) 9.97%.

[0111] Example 4

[0112] Step 1, Corn purification: Wash the corn raw material (containing 13.12% by weight of water) with drinking water to remove the dust on the surface of the corn, separate the shriveled kernels and corn impurities of different sizes, and drain the water;

[0113] Step 2, Soaking and Crushing: Weigh 1240 kg of the purified corn from Step 1 and add it to a 2.0 cubic meter high-pressure reactor. Add 760 kg of water, heat to 63°C, continuously pump water in, and maintain a gauge pressure of 2.25 MPa for 3.5 hours. Using the jet crushing device of this invention, spray the corn into an atmospheric pressure receiving tank at a linear velocity of approximately 67 m / s to obtain corn slurry A. The corn slurry A was measured to have a germ release rate of 100%, a fiber release rate of 84%, a germ-binding starch content of 1.1% by weight, and a fiber-binding starch content of 2.7% by weight.

[0114] Step 3, cyclone separation of germ: The germ of corn slurry A is removed by a cyclone separator, and the remaining slurry is corn slurry B, in which free starch accounts for 31% by weight of the total corn slurry B and the free starch contains 2.7% by weight of protein; the removed germ is washed, extruded and dried using processes known in the art to obtain the germ product;

[0115] Step 4: Separation of free starch: Corn slurry B is fed into gravity curved screen S1. The material on the screen is further pulverized by fine grinding. It is then washed and separated by pressure curved screen S2 to obtain corn slurry C and corn fiber. The corn fiber is further washed, extruded, and dried to obtain the finished fiber. The material under the gravity curved screen S1 is free starch slurry, which is fed into the starch 12-stage wash. Corn slurry C is mixed with the top flow of the 12-stage wash to obtain corn slurry D. Corn slurry D is fed into a vacuum drum filter for filtration, dehydration, and washing to obtain filter cake E and process water, respectively. The underflow of the 12-stage wash is refined starch slurry, which is concentrated and dried to obtain the finished starch. The starch contains 0.32% protein by weight.

[0116] Step 5: Slurry preparation, liquefaction, and saccharification: Mix filter cake E and water to prepare a slurry with a solid content of 38% by weight. Adjust the pH to 5.6-5.8. Add 0.023% by weight of high-temperature liquefaction enzyme (based on the dry weight of corn starch) all at once, and pre-liquefy at 60-65℃ for half an hour. Spray the prepared corn slurry at 108℃ for 15 minutes. Cool to 95℃ and liquefy for another 90 minutes. Control the DE value of the liquefied liquid to 14-18, and the iodine test should be qualified. The DE value of the liquefied liquid was measured to be 17.13, and the iodine test of the free starch in the filter cake was qualified. The pH of the liquefied liquid was adjusted to 4.0-4.2, the temperature was lowered to 63℃, and 0.065 wt% of a saccharifying complex enzyme based on dry corn starch was added. Saccharification was carried out for 10 hours to obtain a saccharified liquid with a DE value of 97.4. The sugar solution was filtered through a vacuum drum filter to obtain the sugar solution and protein. The protein was dried to obtain the finished protein product. The sugar solution was concentrated to 70 wt% to obtain the finished liquid sugar, or further crystallized to obtain the finished glucose product. After drying and weighing, the following yields were obtained: starch yield (DS) 28.43%, sugar yield (DS) 47.37%, pure germ yield (DS) 7.28%, protein yield (DS) 8.56%, and white fiber yield (DS) 9.37%.

[0117] Comparative Example 1

[0118] Step 1: Wash the corn raw material (containing 15.15% by weight of water) with drinking water to remove the dust on the surface of the corn, separate the shriveled kernels and large and small corn impurities, and drain the water;

[0119] Step 2: Weigh 1200 kg of purified corn and 800 kg of water from Step 1 into a 2 cubic meter soaking tank. Add 10 kg of 6% sulfurous acid, heat to 53°C, and maintain the temperature for 48 hours. Sampling and analysis yielded soaked corn A', with a moisture content of 42.3% by weight. The clarified soaking water (corn steep liquor) contained 7.23% by weight of soluble matter, of which the protein content was 3.67% by weight.

[0120] Step 3: The soaked corn A' from Step 2 is crushed using a traditional wet corn milling process with two crushing and two rotating processes to separate the germ, resulting in corn slurry B' and germ containing some fiber. The germ is washed, squeezed, and dried to obtain the finished germ. The amount of starch bound to the germ is measured to be 13.6% by weight. The amount of free starch in corn slurry B' is measured to be 32% by weight, of which the free starch contains 4.8% by weight of protein.

[0121] Step 4: Pump corn slurry B' into gravity curved screen S1. The material on the screen is further pulverized by fine grinding. After washing and separation by pressure curved screen S2, corn slurry C' and corn fiber are obtained. The corn fiber is further washed, squeezed, and dried to obtain finished fiber. The material under the gravity curved screen S1 is free starch slurry, which is fed into the starch 12-stage wash. Corn slurry C' is mixed with the top flow of the 12-stage wash to obtain corn slurry D'. Corn slurry D' is filtered, dehydrated, and washed by a vacuum drum filter to obtain filter cake E and process water. The underflow of the 12-stage wash is refined starch slurry, which is concentrated and dried to obtain starch. This starch contains 1.32% protein by weight. The protein content in the starch exceeds the standard, and the starch is unqualified.

[0122] Step 5: Slurry preparation, liquefaction, and saccharification: Mix filter cake E and water to prepare a slurry with a solid content of 37% by weight. Adjust the pH to 5.6-5.8. Add 0.023% by weight of high-temperature liquefaction enzyme (based on the dry weight of corn starch) all at once, and pre-liquefy at 60-65℃ for half an hour. Spray the prepared corn slurry at 108℃ for 15 minutes. Cool to 95℃ and liquefy for another 90 minutes. Control the DE value of the liquefied liquid to 14-18, and the iodine test should be qualified. The DE value of the liquefied liquid was measured to be 14.27, and the iodine test of the free starch in the filter cake was qualified. The pH of the liquefied liquid was adjusted to 4.0-4.2, the temperature was lowered to 63℃, and 0.065 wt% of a saccharifying complex enzyme based on dry corn starch was added. Saccharification was carried out for 10 hours to obtain a saccharified liquid with a DE value of 96.3. The sugar solution was filtered through a vacuum drum filter to obtain the sugar solution and protein. The protein was dried to obtain commercial protein. The sugar solution was concentrated to 70 wt% to obtain the finished liquid sugar, or further crystallized to obtain commercial glucose. After drying and weighing, the following yields were obtained: starch yield (DS) 27.56%, sugar yield (DS) 44.98%, pure germ yield (DS) 6.23%, protein yield (DS) 5.53%, and sprayed fiber yield (DS) 15.17%.

[0123] It can be seen that in step 2 of Comparative Example 1, the organic matter concentration of the soaking water is too high to be returned to the system as process water. It needs to be concentrated with steam to a water content of 40-50% by weight and sprayed onto corn husks to make sprayed fiber, which can be sold as fiber feed or directly sent to the wastewater treatment system. Using a 12-stage washing process to directly refine the free starch slurry cannot directly yield qualified starch. In addition, the yields of sugar and protein are relatively low. Moreover, the use of sulfite will obviously cause pollution.

[0124] Any implementation described herein may be freely combined with one or more other implementations described herein. Any technical solutions or technical ideas formed thereby shall be regarded as part of the original disclosure or original record of the present invention, and shall not be regarded as new content not disclosed or anticipated herein, unless those skilled in the art consider such combination to be obviously unreasonable.

Claims

1. A method for deep processing corn using a pressure soaking method, particularly for preparing dextrin, syrup and / or sugar, and co-producing starch, as well as indirectly producing germ, protein and fiber, comprising the following steps: (1) Soaking and crushing: Corn raw materials, water and optional chemical additives are continuously or in batches added to a pressure soaking reactor, where a soaking reaction is carried out. Then, the corn is continuously or intermittently crushed by a jet crushing device to obtain a water-containing corn slurry A. (2) Remove the germ from the corn slurry A to obtain corn slurry B and germ; (3) The corn slurry B is fed into a gravity curved screen S1. The material on the S1 screen is finely ground and further pulverized. Then, the fiber is removed by a pressure curved screen S2 to obtain corn slurry C and corn fiber. The material under the S1 screen is fed into a starch 12-stage washing process. The top flow of the 12-stage washing process is mixed with the corn slurry C to obtain corn slurry D. The corn slurry D is filtered and washed simultaneously to obtain filter cake E and process water. The bottom flow of the 12-stage washing process is dehydrated and dried to obtain starch. (4) Filter cake E is slurryed and liquefied. (i) The solids in the liquefied liquid are separated. The solids are further processed to obtain protein. The liquefied liquid after solids separation is dried to obtain dextrin. And / or the liquefied liquid after solids separation is further saccharified to obtain syrup. Or (ii) The liquefied liquid is first further saccharified to obtain saccharified liquid. The solids in the saccharified liquid are then separated to obtain syrup. The solids are further processed to obtain protein. (5) Optionally, the syrup in step (4) is further crystallized to obtain sugar.

2. The method according to claim 1, wherein, Step (1) is carried out as follows: corn raw materials, water and optional chemical additives are continuously or in batches added to the soaking reactor; in the soaking reactor, the reaction is carried out for 0.5-15 hours at a reaction temperature of 20-100℃ and a gauge pressure of 0.1MPa or higher to obtain corn with a water content greater than or equal to 35% by weight. The soaking reactor is maintained at the above gauge pressure or a pressure greater than the above gauge pressure, and then the corn with water content is rapidly crushed through a spray pipe continuously or in batches to obtain corn slurry A.

3. The method according to claim 1 or 2, wherein, The moisture content of the corn raw material is 9-46% by weight, for example, 10-44% by weight, and / or The moisture content of the corn is greater than or equal to 38% by weight, preferably greater than or equal to 40% by weight, and / or The corn raw material is first washed with water to remove impurities from its surface. Optionally, shriveled kernels, large and small corn debris, and any remaining bits of cloth such as gloves, bricks, and iron pieces are removed. Preferably, the corn is drained and then added to a pressure soaking reactor, and / or... The corn slurry A contains germ, fiber, starch, and endosperm, and / or The corn slurry A contains 100% release germ, 78% or more release fiber, and 24-40%, preferably 24-35%, free starch, and / or The pressure soaking reactor is a batch soaking reactor or a tubular soaking reactor, such as a continuous tubular soaking reactor.

4. The method according to any one of claims 1-3, wherein, The pressure soaking reactor is a batch-type soaking reactor, in which corn raw materials are metered and batch-added to the soaking reactor via a screw feeder, and discharged in batches via the jet crushing system of this invention. The soaking reactor is equipped with a distributor, an external heat exchanger (used to heat the corn and soaking water to the required process temperature), and / or an external hot water tank (which provides water for soaking the corn while simultaneously raising the material in the soaking reactor to the required process temperature). The soaking reactor is also connected to an external air or water source (used to pressurize the soaking reactor to the required process pressure). The temperature and pressure of the reactor are precisely controlled by a DCS system. The pressure soaking reactor is a continuous tubular reactor, wherein the reactor is metered by a screw feeder and continuously fed with corn raw materials via a rotary valve, and continuously discharged through an external jet crushing system of the present invention via another rotary valve. The soaking reactor is equipped with a distributor, an external heat exchanger (for heating the corn and soaking water to the required process temperature) and / or an external hot water tank (which provides water for soaking the corn while simultaneously bringing the material in the soaking reactor to the required process temperature). The soaking reactor is also connected to an external air source or water source (for pressurizing the soaking reactor to the required process pressure), and the temperature and pressure of the reactor are precisely controlled by a DCS system.

5. The method according to any one of claims 1-4, wherein, The amount of water added is 30-300% by weight, more preferably 50-200% by weight, even more preferably 60-150% by weight, and even more preferably 65-120% by weight, based on the dry weight of the corn. The pressure soaking reaction temperature is 40-75°C, more preferably 45-70°C, and / or The gauge pressure of the pressure immersion reaction is 0.1-10 MPa, more preferably 0.5-8 MPa, and even more preferably 0.5-6 MPa, and / or The soaking reaction time is 0.5-15 hours, more preferably 0.5-10 hours, and / or After soaking, the pressure soaking reactor is maintained at or above the gauge pressure during the soaking reaction, for example, 0.1-15 MPa, more preferably 0.5-10 MPa, even more preferably 0.5-8 MPa, and even more preferably 1-6 MPa, and / or The linear velocity of the water-containing corn rapidly crushed by the jet pipe is above 10 m / s, especially 50-120 m / s, preferably 55-110 m / s, and / or A suitable gas or water, such as air, nitrogen, oxygen, and / or water, that does not affect the reaction is introduced into the pressure soaking reactor to increase the reactor pressure, and / or In addition to corn and water, a chemical additive is added to the pressure soaking reactor. This chemical additive can be an acid, alkali (containing Lewis acids or alkalis), or enzyme, such as citric acid, acetic acid, oxalic acid, sulfuric acid, hydrochloric acid, sodium sulfite, etc. Preferably, the amount of this chemical additive is 0-10% by weight based on the dry weight of the corn, more preferably 0-1.5% by weight, and even more preferably 0-1% by weight, for example, 0% (neutral soaking), 0.5% by weight, and 1% by weight.

6. The method according to any one of claims 1-5, wherein, Jet pulverization can be completed in one step or multiple steps, and / or In step (2), the germ removal is carried out by a hydrocyclone separator, the hydrocyclone feed pressure of which is preferably greater than 0.25 MPa, so that the obtained germ may contain a small amount of fiber, and / or The 12-stage washing is performed using a starch 12-stage washing device, and / or The gravity curved screen S1 uses 25μm, 50μm, 75μm or 100μm screen gaps, or any intermediate screen gap, and / or The pressure curved screen is a pressure curved screen group, for example, it includes a 1-6 stage washing curved screen, a 1 stage separation curved screen and a 1 stage dewatering curved screen.

7. The method according to any one of claims 1-6, wherein, The dewatering of the refined starch slurry in step (3) is carried out using a pressure drum filter or a scraper centrifuge, and / or In step (3), the corn slurry D is washed and filtered simultaneously using a vacuum drum filter, and / or In step (3), the process of separating solids from the liquefied liquid (or saccharified liquid) involves filtering and washing the protein using a vacuum drum filter (or pressure drum filter or plate and frame filter) to obtain protein containing less than 3% by weight of sugar (or dextrin), and / or In step (3), the fine grinding is needle grinding. In step (4), the pH of the liquefied liquid is adjusted to 4.0-4.4, preferably 4.0-4.2, for saccharification, and / or In step (4), the saccharification is carried out, for example, by adding a saccharifying enzyme (e.g., a saccharifying complex enzyme), the amount of which is, for example, 0.01-0.07% by weight based on dry corn starch, and the DE value of the saccharified liquid after saccharification is preferably 95-98, and / or In step (4), filter cake E is saccharified by adding water to adjust the slurry, adjusting the pH value, adding enzymes for liquefaction, and saccharification; the saccharified solution is filtered to obtain syrup and solid filter cake, and the solid filter cake is washed and further processed to obtain protein, and / or In step (4), the preferred temperature for slurry preparation is 60-65°C, and the preferred pH is 5.5-6. Liquefaction is carried out, for example, by spraying. This liquefaction process can be a single spray, a double spray, or gentle liquefaction at 76-100°C. A liquefying enzyme (e.g., a high-temperature liquefying enzyme) is added, which can be added once or twice, preferably twice, at a preferred amount of 0.1-0.5 kg / ton of dry corn starch. The DE value of the liquefied liquid is preferably controlled to be 14-18, and / or In step (5), the syrup may be further filtered, decolorized, ion-exchanged and / or concentrated and then crystallized to obtain sugar, preferably glucose.

8. A soaking and crushing apparatus, particularly an apparatus for carrying out the method according to any one of claims 1-7, comprising a corn feeder, a pressure soaking reactor, a gas compressor and / or a water pump, a venturi tube, a water tank, and a jet pipe, wherein the gas compressor and / or water pump, the corn feeder, and the water tank are connected to the soaking reactor, and the venturi tube and the jet pipe are connected in sequence from the outlet of the pressure soaking reactor.

9. The device according to claim 8, wherein The corn feeder mentioned above includes a screw feeder, belt scale, lifting hopper, rotary valve, etc., and / or The pressure soaking reactor is a batch soaking reactor or a tubular soaking reactor, such as a continuous tubular soaking reactor, and / or The gas compressor and water pump can be used individually, in series, or in parallel, and / or The water supply tank is a hot water supply tank to provide the appropriate temperature required for soaking, and / or The diameter of the injection nozzle is smaller than that of the venturi nozzle, and / or The pressure soaking reactor may be equipped with a bottom valve or a rotary valve.

10. The syrup, sugar, starch, dextrin, germ, corn fiber and / or protein obtained by the method according to any one of claims 1-7.

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