Method for extracting effective components in corn soaking water

Abstract

The invention discloses a method for extracting effective components in corn soaking water, which comprises the following steps: adsorbing phytic acid in the corn soaking water through resin, removing corn protein and calcium and magnesium salt from the obtained effluent to obtain a treatment solution, filtering and concentrating through a reverse osmosis membrane to obtain a first trapped fluid, adding hydrochloric acid into the first trapped fluid to adjust the pH value to 2.0-2.5, and filtering to obtain a second trapped fluid; carrying out vacuum concentration until crystals are separated out, closing vacuum, carrying out cooling crystallization to obtain a KCl crude product and a first filtrate, and distilling the first filtrate to obtain a lactic acid solution and a dry distillation product. According to the method, the crude potassium chloride product, the lactic acid solution and the distilled dry matter are effectively separated from the corn soaking water, effective components in the corn soaking water are fully extracted, separated and utilized, and the comprehensive economic benefits of a corn processing industry chain are improved.

Description

Technical Field

[0001] The invention relates to the technical field of comprehensive utilization of corn soaking water, and in particular to a method for extracting effective components in corn soaking water. Background Art

[0002] In the process of producing corn starch by wet milling, corn soaking water is the main production wastewater. Generally speaking, about 0.8 tons of corn soaking water is produced when 1 ton of corn is processed. my country is the world's largest corn starch producer, producing about 30 million tons of corn starch each year, most of which is produced by wet milling, and about 35 million tons of corn soaking water is produced each year. Corn soaking water contains substances such as protein, phytic acid, lactic acid, sugars, starch residues and inorganic salts.

[0003] In the prior art, the method for treating corn soaking water is to allow the corn soaking water to enter an anion resin to adsorb phytic acid, and the phytic acid is desorbed to obtain potassium phytate; the effluent is first filtered through a ceramic membrane to remove large molecular crude protein and large particle impurities, and then concentrated through a nanofiltration membrane, and the retained liquid is spray-dried to obtain a corn protein product; and the permeate is concentrated to a solid content of 30-35% through a reverse osmosis membrane and sold in the form of organic fertilizer.

[0004] In the above-mentioned method for treating corn soaking water, the permeate after nanofiltration membrane concentration still contains a lot of valuable substances that have not been fully utilized, and there is also a safety risk caused by the inability to completely remove aflatoxin and vomitoxin.

[0005] Therefore, it is urgent to establish a method in the prior art to fully utilize the components in corn soaking water to improve the comprehensive economic benefits of the corn processing industry chain. Summary of the invention

[0006] In view of this, the purpose of the present invention is to provide a method for extracting effective ingredients in corn soaked water, which overcomes the technical defects of the prior art that the effective ingredients in corn soaked water cannot be effectively extracted and fully utilized, fully separates and utilizes the effective ingredients in corn soaked water, and improves the comprehensive economic benefits of the corn processing industry chain.

[0007] In order to achieve the above object, the present invention provides a method for extracting effective ingredients from corn soaking water, comprising the following steps:

[0008] The corn soaking water is passed through an anion exchange resin to absorb phytic acid to obtain an effluent;

[0009] The effluent is treated by removing corn protein and calcium and magnesium salts to obtain a treated liquid;

[0010] The treated liquid enters a reverse osmosis membrane with a molecular weight cutoff of 50-100Da to obtain a first retentate and a permeate;

[0011] The first retentate is kept at 120-140° C. and 0.2-0.3 MPa for 0.5-2 h, cooled to below 100° C. at normal pressure, hydrochloric acid is added thereto to adjust the pH to 2.0-2.5, and vacuum concentrated until crystals precipitate in the solution to obtain a concentrated solution;

[0012] The concentrated solution is cooled to 30° C. for crystallization. After the crystallization is completed, a first filtration is performed to obtain a crude KCl product and a first filtrate;

[0013] The first filtrate is distilled, and the fraction under the condition of 82-85°C / 100Pa is collected to obtain a lactic acid solution and a distilled dry product.

[0014] The invention provides a method for extracting effective components from corn soaked water. Firstly, phytic acid in the corn soaked water is adsorbed by using an anion exchange resin to remove the phytic acid in the corn soaked water. The effluent after adsorption is treated to remove corn protein and calcium and magnesium salts to obtain a treated liquid, thereby realizing the preliminary separation of impurities. The treated liquid enters a reverse osmosis membrane for concentration to obtain a first retentate, and the first retentate is adjusted to pH 2.0-2.5 by adding hydrochloric acid. The pH is adjusted by adding hydrochloric acid so that potassium lactate in the solution is converted into lactic acid and potassium chloride, thereby preparing for subsequent separation to obtain potassium chloride and lactic acid. When vacuum concentration is performed until crystals are precipitated, the vacuum can be closed and cooling crystallization can be performed. Through cooling crystallization, potassium chloride is precipitated to obtain a crude potassium chloride product and a first filtrate. The first filtrate mainly contains lactic acid and protein small peptides. A lactic acid solution and a distilled dry matter can be obtained through high vacuum distillation. The distilled dry matter is a mixture solid whose main component is small peptides. The invention separates and prepares crude potassium chloride, lactic acid solution and distilled dry matter (small peptide product) from corn soaking water, fully extracts, separates and utilizes effective components in the corn soaking water, enriches the utilization methods of the corn soaking water, and improves the comprehensive economic benefits of the corn processing industry chain. DETAILED DESCRIPTION

[0015] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0016] The present invention provides a method for extracting effective components from corn soaked water, comprising the following steps:

[0017] The corn soaking water is passed through an anion exchange resin to absorb phytic acid to obtain an effluent;

[0018] The effluent is treated by removing corn protein and calcium and magnesium salts to obtain a treated liquid;

[0019] The treated liquid enters a reverse osmosis membrane with a molecular weight cutoff of 50-100Da to obtain a first retentate and a permeate;

[0020] The first retentate is kept at 120-140° C. and 0.2-0.3 MPa for 0.5-2 h, cooled to below 100° C. at normal pressure, hydrochloric acid is added thereto to adjust the pH to 2.0-2.5, and vacuum concentrated until crystals precipitate in the solution to obtain a concentrated solution;

[0021] The concentrated solution is cooled to 30° C. for crystallization. After the crystallization is completed, a first filtration is performed to obtain a crude KCl product and a first filtrate;

[0022] The first filtrate is distilled, and the fraction under the condition of 82-85°C / 100Pa is collected to obtain a lactic acid solution and a distilled dry product.

[0023] The present invention firstly allows corn steep water to adsorb phytic acid through an anion exchange resin to obtain an effluent. In the present invention, the anion exchange resin is preferably a macroporous weakly alkaline anion exchange resin, such as D301, D354, D370, and D351; the feed amount of the corn steep water is preferably 6-10BV of the volume of the anion exchange resin, and the feed rate is preferably 1-2BV / h. The present invention has no special restrictions on the feeding method of corn steep water, and the commonly used methods in the art can be used, such as pumping feeding; the present invention has no special restrictions on the carrier of the resin, and the common carriers in the art can be used, such as resin columns. It should be understood that the purpose of the anion exchange resin adsorption is to adsorb and remove phytic acid in corn steep water, and the effluent after resin adsorption is corn steep water after the phytic acid is removed.

[0024] Furthermore, before the corn soaking water is adsorbed by anion exchange resin for phytic acid, the present invention further includes: pre-treating the corn soaking water to remove impurities. In the present invention, the pre-treatment preferably includes standing at 45-50°C, using a hydrocyclone or using a microfiltration membrane to remove impurities. The standing time for impurity removal is preferably 4-6h; the working parameters of the hydrocyclone are preferably: the ratio of the diameter of the body to the diameter of the overflow pipe is (2-3): 1, the ratio of the bottom flow to the feed amount is 1: (20-30); the pore size of the microfiltration membrane is preferably 0.5-1um. It should be understood that the pre-treatment step of the present invention before feeding the corn soaking water to the resin for adsorption is mainly to remove solid impurities such as starch and corn husks suspended in the solution. Therefore, the present invention can adopt standing, using the gravity of the impurities to naturally settle to remove impurities, or using a hydrocyclone to separate the suspended impurities from the suspension using the centrifugal sedimentation principle. In addition, the present invention can also use membrane filtration to separate the above impurities from the solution. The separated suspended impurities can be returned to the corn starch factory again and concentrated to prepare corn starch powder, thus realizing the economic utilization of production waste.

[0025] After the effluent is obtained by adsorption by anion exchange resin, the present invention removes corn protein and calcium and magnesium salts from the effluent to obtain a treated liquid. In the present invention, the effluent is treated by removing corn crude protein and calcium and magnesium salts to obtain a treated liquid, including: adding potassium hydroxide to the effluent, adjusting the pH to 12-13, and obtaining a filter cake and a treated liquid containing crude protein and calcium and magnesium salts by a second filtration. In the present invention, the potassium hydroxide is preferably solid potassium hydroxide or a potassium hydroxide solution with a mass concentration of 30-45%, more preferably solid potassium hydroxide; there are three purposes for adding potassium hydroxide, one is to adjust the pH of the solution, promote the sedimentation / precipitation and separation of protein and calcium and magnesium salts; the second is to add potassium ions to the solution to provide a material basis for the subsequent preparation of potassium chloride products; the third is to keep the pH value of the filtrate alkaline, combined with the subsequent heating to 120°C-140°C and 0.2-0.3Mpa insulation conditions, it can effectively destroy and inactivate aflatoxin and vomitoxin, reduce and eliminate the toxicity caused by aflatoxin and vomitoxin. In the present invention, the filtration pore size of the second filtration is preferably 20-80 um. The present invention has no special limitation on the equipment for the second filtration, for example, a centrifuge can be used.

[0026] Furthermore, after obtaining the treated liquid, the present invention further comprises: treating the treated liquid with a nanofiltration membrane having a molecular weight cutoff of 450-550Da to obtain a second retentate containing corn protein and a treated liquid treated with the nanofiltration membrane before the treated liquid enters the reverse osmosis membrane having a molecular weight cutoff of 50-100Da after removing corn protein and removing calcium and magnesium salts from the effluent to obtain the treated liquid. In the present invention, after obtaining the second retentate containing corn protein, it further comprises: keeping the second retentate at 120-140°C and 0.2-0.3Mpa for 0.5-2h, cooling it down to below 100°C at normal pressure, adding a small amount of concentrated hydrochloric acid thereto to adjust the pH to neutral, and then spray drying it to obtain a corn protein powder product; the inlet air temperature of the spray drying is preferably 120-140°C, and the outlet air temperature is preferably 90-100°C.

[0027] After obtaining the treated liquid or the treated liquid treated by the nanofiltration membrane, the present invention allows the treated liquid or the treated liquid treated by the nanofiltration membrane to enter a reverse osmosis membrane with a molecular weight cutoff of 50-100Da to obtain a first retentate and a permeate. In the present invention, the reverse osmosis membrane mainly functions to concentrate the treated liquid. Preferably, when the refractive solid content of the first retentate reaches 32-35%, the reverse osmosis membrane concentration process is considered to be completed; the main component of the permeate is water.

[0028] After obtaining the first retentate, the present invention keeps the first retentate at 120-140°C and 0.2-0.3Mpa for 0.5-2h, cools it down to below 100°C at normal pressure, adds hydrochloric acid to adjust the pH to 2.0-2.5, and vacuum concentrates it until crystals precipitate in the solution to obtain a concentrated solution. The purpose of the insulation in the present invention is to destroy and inactivate aflatoxin and vomitoxin under these conditions, reduce and eliminate the toxicity of the final product, and improve its safety. In the present invention, the mass concentration of the hydrochloric acid is preferably 25-40%; the vacuum degree of the vacuum concentration is preferably -0.07MPa to -0.09MPa, and the temperature is preferably 60-70°C. The purpose of the vacuum concentration in the present invention is to increase the concentration of the solution and create conditions for the subsequent cooling and crystallization of potassium chloride.

[0029] After obtaining the concentrated solution, the present invention cools the concentrated solution to 30°C for crystallization. After the crystallization is completed, the crude KCl product and the first filtrate are obtained by the first filtration. In the present invention, the crystallization is preferably a cooling crystallization, and the cooling crystallization rate is preferably 5-10°C / h; the filtration pore size of the first filtration is preferably 20-80um. The present invention has no special limitation on the equipment for the first filtration, for example, a centrifuge can be used. After obtaining the crude KCl product, the present invention also includes rinsing it with purified water to further remove impurities.

[0030] Furthermore, after obtaining the first filtrate, the present invention also includes: adsorbing the first filtrate by a strong acid cationic resin before distilling the first filtrate; desorbing the adsorbed resin with 15-40wt% hydrochloric acid to obtain a desorbed solution; mixing the desorbed solution with the first retentate, and continuing with subsequent steps. The purpose of using cationic resin for adsorption and desorption in this step of the present invention is to adsorb and separate potassium chloride in the solution, and return to the concentration step before cooling and crystallization, and continue with the subsequent steps to prepare potassium chloride after mixing with the first retentate, and further recover the potassium chloride that has not been crystallized in the first filtrate, thereby improving the yield of potassium chloride.

[0031] After obtaining the first filtrate, the present invention distills the first filtrate, collects the fraction under the condition of 82-85°C / 100Pa, and obtains a lactic acid solution and a distilled dry matter. In the present invention, distilling the first filtrate, collecting the fraction under the condition of 82-85°C / 100Pa, and obtaining the lactic acid solution and the distilled dry matter comprises: distilling out part of the water from the first filtrate under the condition of -0.09MPa to -0.095MPa vacuum and 60-70°C, then distilling under the condition of absolute pressure of 50-150Pa and 90-100°C, and collecting the lactic acid solution and distilled dry matter obtained under the condition of 82-85°C / 100Pa. In the present invention, the main components of the first filtrate are lactic acid and small peptides; the separation of the lactic acid and small peptides in the present invention is mainly carried out by distillation, which specifically includes two stages: the first stage is to distill out 60-75% of water under a vacuum degree of -0.09MPa to -0.095Mpa and a temperature of 60-70°C. Under these conditions, the boiling point of water is reduced, and part of the water can be removed by distillation, which is convenient for subsequent distillation to obtain a lactic acid solution with a higher concentration, and lactic acid will not be evaporated under these conditions; the second stage is to increase the temperature to 90-100°C and the pressure to an absolute pressure of 50-150Pa. Under these conditions, lactic acid and part of the water are evaporated, and the fraction under the conditions of 82-85°C / 100Pa is collected to obtain a lactic acid solution; the main component of the distilled dry matter is small peptides.

[0032] Furthermore, after obtaining the distilled dry matter, the present invention further comprises: dissolving the distilled dry matter in water, decolorizing the solution with activated carbon, filtering for the third time to obtain a decolorized liquid, and concentrating the decolorized liquid to obtain a small peptide concentrate with a solid content of 30-35%. The present invention has no special restrictions on the pore size and source of the activated carbon, and conventional parameters in the field and commercial sources can be used; the present invention has no special restrictions on the filtration pore size and filtration equipment of the third filtration, and it can separate the activated carbon from the decolorized liquid after decolorization; the present invention has no special restrictions on the concentrating equipment, and it can achieve the concentration of the decolorized liquid to a solid content of 30-35%.

[0033] In order to better illustrate the technical solution of the present invention, the present invention also provides the following specific embodiments. It should be understood that the raw materials used in the following embodiments are all commercially available raw materials unless otherwise specified. In particular, the main components of 3 batches of corn soaking water are listed in Table 1 below, and the batches of corn soaking water are all provided by Zhucheng Haotian Pharmaceutical Co., Ltd.

[0034] Table 11-3 Batches of corn soaking water

[0035] batch protein lactic acid Phytic Acid carbohydrate Starch residue Inorganic salt water 1 6.5％ 2.6％ 1.15％ 0.1％ 0.8％ 1.1％ 87.75％ 2 6.4％ 2.5％ 1.15％ 0.1％ 0.9％ 1.0％ 87.95％ 3 6.7％ 2.6％ 1.1％ 0.1％ 0.9％ 1.1％ 87.50％

[0036] Example 1

[0037] S1. Take 660L of corn soaking water from batch 1, and adsorb phytic acid through 80L of macroporous weakly basic resin (model D-301) (feed rate of 1.5BV / h) to obtain 625L of effluent;

[0038] S2. 25 kg of solid potassium hydroxide was added to the effluent to adjust the pH to 12.3, and 34.8 kg of filter cake containing crude protein and calcium and magnesium salts and 612 L of treated liquid were obtained by centrifuge filtration at 40 um;

[0039] S3. The treated liquid enters a reverse osmosis membrane with a molecular weight cutoff of 75Da to obtain 260L of the first retentate and 352L of the permeate;

[0040] S4. The first retentate was kept at 130°C and 0.25 MPa for 1 h, cooled to 95°C at normal pressure, 30% hydrochloric acid was added thereto to adjust the pH to 2.2, and vacuum concentrated (vacuum degree -0.08 MPa, temperature 65°C) until crystals precipitated in the solution to obtain 125 L of concentrated solution;

[0041] S5. The concentrate was cooled and crystallized at a rate of 8°C / h. After the temperature dropped to 30°C, 18.2kg of crude KCl (dried, purity 95wt%) and 109L of the first filtrate were obtained by filtration through a 40um centrifuge;

[0042] S6. Distill the first filtrate under -0.09MPa vacuum and 65°C to obtain 55L of water, then distill it under an absolute pressure of 100Pa and 95°C, and collect the fractions under 85°C / 100Pa to obtain 20L of lactic acid solution (mass concentration of 48%) and 55.2kg of distilled dry matter.

[0043] Example 2

[0044] S1. Take 660L of corn soaking water from batch 2, and adsorb phytic acid through 80L of macroporous weakly basic resin (model D-354) (feed rate of 1.5BV / h) to obtain 630L of effluent;

[0045] S2. 25.2 kg of solid potassium hydroxide was added to the effluent to adjust the pH to 12.4, and 60 um centrifuge was used to obtain 35.0 kg of filter cake containing crude protein and calcium and magnesium salts and 615 L of treated liquid;

[0046] S3. The treated liquid was treated with a 500Da nanofiltration membrane to obtain 125L of a second retentate and 490L of a treated liquid treated with a nanofiltration membrane;

[0047] S4. The treated liquid treated by the nanofiltration membrane enters a reverse osmosis membrane with a molecular weight cutoff of 75Da to obtain 240L of the first retentate and 250L of the permeate;

[0048] S5. The first retentate was kept at 130°C and 0.25 MPa for 1 h, cooled to 95°C at normal pressure, 30% hydrochloric acid was added thereto to adjust the pH to 2.2, and vacuum concentrated (vacuum degree -0.08 MPa, temperature 65°C) until crystals precipitated in the solution to obtain 91 L of concentrated solution;

[0049] S6. The concentrate was cooled and crystallized at a rate of 8°C / h. After the temperature dropped to 30°C, 19.0kg of crude KCl (dried, purity 96wt%) and 76L of the first filtrate were obtained by 60um centrifuge filtration;

[0050] S7. Distill the first filtrate under -0.09MPa vacuum and 65°C to obtain 54.5L of water, then distill it under an absolute pressure of 100Pa and 95°C, and collect the fractions under 85°C / 100Pa to obtain 21.5L of lactic acid solution (mass concentration of 50%) and 21.0kg of distilled dry matter.

[0051] Example 3

[0052] S1. Take 660L of corn soaking water from batch 1 and let it stand at 45°C for 5h to obtain 650L of supernatant;

[0053] S2. The supernatant was passed through 80 L of macroporous weakly basic resin (model D-370) (feed rate of 1.5 BV / h) to adsorb phytic acid to obtain 620 L of effluent;

[0054] S3. 25kg of solid potassium hydroxide was added to the effluent to adjust the pH to 12.3, and 34.6kg of filter cake containing crude protein and calcium and magnesium salts and 610L of treated liquid were obtained by centrifuge filtration at 70um;

[0055] S4. The treated liquid was treated with a 500Da nanofiltration membrane to obtain 120L of the second retentate and 490L of the treated liquid treated with the nanofiltration membrane;

[0056] S5. The treated liquid treated by the nanofiltration membrane enters a reverse osmosis membrane with a molecular weight cutoff of 75Da to obtain 240L of the first retentate and 250L of the permeate;

[0057] S6. The first retentate was kept at 130°C and 0.25 MPa for 1 h, cooled to 95°C at normal pressure, 30% hydrochloric acid was added thereto to adjust the pH to 2.2, and vacuum concentrated (vacuum degree -0.08 MPa, temperature 65°C) until crystals precipitated in the solution to obtain 90 L of concentrated solution;

[0058] S7. The concentrate was cooled and crystallized at a rate of 8°C / h. After the temperature dropped to 30°C, 19.3kg of crude KCl (dried, purity 98wt%) and 75L of the first filtrate were obtained by filtration using a 70um centrifuge;

[0059] S8. Distill the first filtrate under -0.09MPa vacuum and 65°C to obtain 53L of water, then distill it under an absolute pressure of 100Pa and 95°C, and collect the fractions under 85°C / 100Pa to obtain 22L of lactic acid solution (mass concentration of 50%) and 20.1kg of distilled dry matter.

[0060] Example 4

[0061] S1. Take 660L of corn soaking water from batch 2 and separate it into 648L of supernatant by hydrocyclone (body diameter to overflow pipe diameter ratio 2.5:1, bottom flow to feed ratio 1:25);

[0062] S2. The supernatant was passed through 108 L of macroporous weakly basic resin (model D-351) (feed rate was 2 BV / h) to adsorb phytic acid to obtain 618 L of effluent;

[0063] S3. 24kg of solid potassium hydroxide was added to the effluent to adjust the pH to 12, and 35.0kg of filter cake containing crude protein and calcium and magnesium salts and 606L of treated liquid were obtained by centrifuge filtration at 20um;

[0064] S4. The treated liquid was treated with a 450Da nanofiltration membrane to obtain 116L of the second retentate and 490L of the treated liquid treated with the nanofiltration membrane;

[0065] S5. The treated liquid treated by the nanofiltration membrane enters a reverse osmosis membrane with a molecular weight cutoff of 50Da to obtain 245L of the first retentate and 245L of the permeate;

[0066] S6. The first retentate was kept at 120°C and 0.3 MPa for 0.5 h, cooled to 90°C at normal pressure, 40% hydrochloric acid was added thereto to adjust the pH to 2.0, and vacuum concentrated (vacuum degree -0.07 MPa, temperature 60°C) until crystals precipitated in the solution to obtain 90 L of concentrated solution;

[0067] S7. The concentrate was cooled and crystallized at a rate of 5°C / h. After the temperature dropped to 30°C, 19.0 kg of crude KCl (dried, purity 97 wt%) and 73 L of the first filtrate were obtained by filtration using a 20 um centrifuge;

[0068] S8. Distill the first filtrate under -0.09MPa vacuum and 60°C to obtain 52L of water, then distill it under an absolute pressure of 50Pa and 90°C, and collect the fractions under 82°C / 100Pa to obtain 21L of lactic acid solution (mass concentration of 49%) and 20.5kg of distilled dry matter.

[0069] Example 5

[0070] S1. Take 660L of corn soaking water from batch 3 and filter it through a microfiltration membrane with a pore size of 0.5-1um to obtain 650L of supernatant;

[0071] S2. The supernatant was passed through 65 L of macroporous weakly basic resin (model D-301) (feed rate of 1 BV / h) to adsorb phytic acid to obtain 620 L of effluent;

[0072] S3. Add 62.5L potassium hydroxide solution (mass concentration of 40%) to the effluent to adjust the pH to 13, and filter through an 80um centrifuge to obtain 34.4kg of filter cake containing crude protein and calcium and magnesium salts and 672L of treated liquid;

[0073] S4. The treated liquid was treated with a 550Da nanofiltration membrane to obtain 140L of the second retentate and 532L of the treated liquid treated with the nanofiltration membrane;

[0074] S5. The treated liquid treated by the nanofiltration membrane enters a reverse osmosis membrane with a molecular weight cutoff of 100Da to obtain 260L of the first retentate and 272L of the permeate;

[0075] S6. The first retentate was kept at 140°C and 0.2 MPa for 2 h, cooled to 98°C at normal pressure, 25% hydrochloric acid was added thereto to adjust the pH to 2.5, and vacuum concentrated (vacuum degree -0.09 MPa, temperature 70°C) until crystals precipitated in the solution to obtain 90 L of concentrated solution;

[0076] S7. The concentrate was cooled and crystallized at a rate of 10°C / h. After the temperature dropped to 30°C, 18.8kg of crude KCl (dried, purity 98wt%) and 75L of the first filtrate were obtained by 80um centrifuge filtration;

[0077] S8. Distill out part of the water from the first filtrate under a vacuum of -0.095 MPa and 70°C, then distill under an absolute pressure of 150 Pa and 100°C, and collect the fractions under 83°C / 100Pa to obtain 25 L of lactic acid solution (mass concentration of 45%) and 21.1 kg of distilled dry matter.

[0078] Example 6

[0079] S1. The 120 L second retentate obtained in step S4 of Example 3 was kept at 130 ° C and 0.25 MPa for 1 h, and then cooled to 95 ° C at normal pressure;

[0080] S2. Concentrated hydrochloric acid was added thereto to adjust the pH to neutral, and the mixture was spray dried (with an inlet air temperature of 130°C and an outlet air temperature of 95°C) to obtain 36 kg of corn protein powder.

[0081] Example 7

[0082] S1. The 120L second retentate obtained in step S4 of Example 4 was kept at 120°C and 0.3Mpa for 0.5h and then cooled to 90°C at normal pressure;

[0083] S2. Concentrated hydrochloric acid was added thereto to adjust the pH to neutral, and the mixture was spray dried (with an inlet air temperature of 120°C and an outlet air temperature of 100°C) to obtain 35.8 kg of corn protein powder.

[0084] Example 8

[0085] S1. The 120 L second retentate obtained in step S4 of Example 5 was kept at 140 ° C and 0.2 MPa for 2 h, and then cooled to 98 ° C at normal pressure;

[0086] S2. Concentrated hydrochloric acid was added thereto to adjust the pH to neutral, and the mixture was spray dried (with an inlet air temperature of 140°C and an outlet air temperature of 90°C) to obtain 35.8 kg of corn protein powder.

[0087] Example 9

[0088] S1. The distilled dry matter in Example 3 was dissolved in purified water, 400 g of activated carbon was added, and 66 L of decolorized liquid was obtained after filtration. The solution was concentrated in vacuo to obtain a solid content of 50%, and spray-dried (inlet air temperature was 130°C, outlet air temperature was 95°C) to obtain 15 kg of small peptide protein powder.

[0089] Example 10

[0090] S1. The distilled dry matter in Example 4 was dissolved in purified water, 390 g of activated carbon was added, and 67 L of decolorized liquid was obtained after filtration. The decolorized liquid was concentrated in vacuo to obtain 40 L of a small peptide solution with a solid content of 50%.

[0091] Embodiment 11

[0092] S1. The distilled dry matter in Example 5 was dissolved in purified water, 400 g of activated carbon was added, and 68 L of decolorized liquid was obtained after filtration. The decolorized liquid was concentrated in vacuo to obtain 41 L of a small peptide solution with a solid content of 50%.

[0093] Comparative Example 1

[0094] The step S3 in Example 3, "adding solid potassium hydroxide to the effluent to adjust the pH to 12.3" is adjusted to (adding solid potassium hydroxide to the effluent to adjust the pH to 11), and other conditions remain unchanged.

[0095] The results showed that 15.4 kg of crude KCl (dried, purity 82 wt%), 20 L of lactic acid solution (mass concentration 48%) and 20.0 kg of distilled dry matter were obtained.

[0096] The results in Comparative Example 1 show that after the pH adjusted by solid potassium hydroxide is lowered, the amount of crude KCl obtained is significantly reduced, and the concentration of the lactic acid solution and the weight of the distilled dry matter are slightly reduced. This is because the decrease in pH corresponds to a decrease in the amount of potassium hydroxide added, which mainly affects the yield of the crude KCl product because the amount of potassium ions provided as a raw material is reduced. In addition, it also partially affects the concentration of the lactic acid solution and the weight of the distilled dry matter. This is because after the amount of potassium hydroxide added is reduced, the removal rate of impurity ions such as calcium and magnesium is reduced (calcium and magnesium ions are precipitated more obviously when the pH is 12-13), and the impurity removal effect affects the subsequent separation of lactic acid and distilled dry matter.

[0097] Comparative Example 2

[0098] The step S6 in Example 4, "adding hydrochloric acid with a mass concentration of 40% to adjust the pH to 2.0" is adjusted to "adding hydrochloric acid with a mass concentration of 40% to adjust the pH to 3.0", and other conditions remain unchanged.

[0099] The results showed that 17.4 kg of crude KCl (dry, purity 90 wt%), 20 L of lactic acid solution (mass concentration 50%) and 22.6 kg of distilled dry matter were obtained.

[0100] The results of Comparative Example 2 show that after reducing the amount of hydrochloric acid added to increase the pH value, the output of crude KCl decreases, the lactic acid solution remains basically unchanged (the total amount increases slightly but the concentration decreases slightly), and the amount of distilled dry matter increases. This is because the solution containing potassium chloride is not a pure solution of potassium chloride, but also contains other impurity ions. In the crystallization process of the potassium chloride solution containing multiple ions, it is necessary to control a certain pH to ensure the stability of potassium chloride and reduce the influence of other ions on the precipitation of potassium chloride. In Comparative Example 2, after the pH is increased, potassium chloride cannot maintain a relatively stable state. Potassium ions and chloride ions exist in the form of other compounds, so they cannot be precipitated by crystallization and remain in the solution. This is why the distilled dry matter increases in Comparative Example 2.

[0101] Test Case

[0102] A. The purity of KCl is determined in accordance with the national standard GB / T 13885-2017;

[0103] B. The concentration of the lactic acid solution is implemented in accordance with the national standard GB 5009.157-2016.

[0104] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for extracting effective ingredients from corn soaked water, characterized in that: The following steps are involved: The corn soaking water is passed through an anion exchange resin to absorb phytic acid to obtain an effluent; The effluent is treated by removing corn protein and calcium and magnesium salts to obtain a treated liquid; The treated liquid enters a reverse osmosis membrane with a molecular weight cutoff of 50-100Da to obtain a first retentate and a permeate; The first retentate is kept at 120-140° C. and 0.2-0.3 MPa for 0.5-2 h, cooled to below 100° C. at normal pressure, hydrochloric acid is added thereto to adjust the pH to 2.0-2.5, and vacuum concentrated until crystals precipitate in the solution to obtain a concentrated solution; The concentrated solution is cooled to 30° C. for crystallization. After the crystallization is completed, a first filtration is performed to obtain a crude KCl product and a first filtrate; The first filtrate is distilled, and the fraction under the condition of 82-85°C / 100Pa is collected to obtain a lactic acid solution and a distilled dry product.

2. The method according to claim 1, characterized in that The effluent is treated by removing corn crude protein and calcium and magnesium salts to obtain a treated liquid comprising: Potassium hydroxide is added to the effluent to adjust the pH to 12-13, and a filter cake and a treated liquid containing crude protein and calcium and magnesium salts are obtained through a second filtration.

3. The method according to claim 1 or 2, characterized in that: After the effluent is treated by removing corn protein and calcium and magnesium salts to obtain a treated liquid, the treated liquid enters a reverse osmosis membrane with a molecular weight cutoff of 50-100Da, and further comprises: The treated liquid is treated with a nanofiltration membrane having a molecular weight cutoff of 450-550 Da to obtain a second retentate containing corn protein and a treated liquid treated with the nanofiltration membrane.

4. The method according to claim 1, characterized in that: The mass concentration of the hydrochloric acid is 25-40%; and / or, The vacuum degree of the vacuum concentration is -0.07MPa to -0.09MPa, and the temperature is 60-70°C.

5. The method according to claim 1, characterized in that The crystallization is cooling crystallization, and the rate of cooling crystallization is 5-10°C / h; and / or, The first filtration is performed using a centrifuge with a filtration pore size of 20-80 um.

6. The method according to claim 1, characterized in that The first filtrate is distilled, and the fraction at 82-85°C / 100Pa is collected to obtain a lactic acid solution and a distilled dry matter including: The first filtrate is distilled to remove part of the water under the conditions of -0.09MPa to -0.095MPa vacuum and 60-70°C, and then distilled under the conditions of 50-150Pa absolute pressure and 90-100°C, and the lactic acid solution and distilled dry matter obtained under the conditions of 82-85°C / 100Pa are collected.

7. The method according to claim 1 or 6, characterized in that: After obtaining the distilled dry matter, it also includes: The distilled dry matter is dissolved in water, the solution is decolorized by activated carbon, and a decolorized solution is obtained by a third filtration. The decolorized solution is concentrated to obtain a small peptide concentrate with a solid content of 30-35%.

8. The method according to claim 1, characterized in that After obtaining the first filtrate and before distilling the first filtrate, the method further comprises: Adsorbing the first filtrate through a strongly acidic cationic resin; The adsorbed resin is analyzed with 15-40wt% hydrochloric acid to obtain an analytical solution; The analytical solution is mixed with the first retentate solution and the subsequent steps are continued.

9. The method according to claim 3, characterized in that: After obtaining the second retentate, the method further comprises: The second retentate is kept at 120-140° C. and 0.2-0.3 MPa for 0.5-2 h; Add concentrated hydrochloric acid to the reaction solution to adjust the pH to neutral; Corn gluten meal is obtained by spray drying.

10. The method according to claim 1, characterized in that Before the corn steep water is passed through an anion exchange resin to absorb phytic acid, it also includes: Pre-treating the corn soaking water to remove impurities; The pretreatment includes standing at 45-50°C, using a hydrocyclone separator or a microfiltration membrane to remove impurities.