CN112456713A

CN112456713A - Process and equipment for recovering and treating protein in bean product wastewater

Info

Publication number: CN112456713A
Application number: CN202011327491.2A
Authority: CN
Inventors: 叶伟炳; 崔玉玉
Original assignee: Guangdong Wenyang Environmental Technology Co ltd
Current assignee: Guangdong Wenyang Environmental Technology Co ltd
Priority date: 2020-11-24
Filing date: 2020-11-24
Publication date: 2021-03-09

Abstract

The invention relates to the field of wastewater treatment, in particular to a process and equipment for recovering and treating protein in bean product wastewater. The invention realizes the recovery of protein in the bean product wastewater with high protein content by adopting the combined use of an ion exchange system, an ultrafiltration system, a vacuum drying system and an MVR forced circulation system, the recovery rate can reach more than 90 percent, and the purity of the recovered protein solid can reach more than 80 percent. The ion exchange system has tentatively promoted the purity of retrieving protein, and vacuum drying realizes the drying of volatilizing to protein solution at low temperature for the difficult inactivation degeneration of protein, and the energy consumption has effectively been saved in the use of MVR system, and makes the protein mass energy in the waste water after the preliminary treatment further retrieved, is showing the rate of recovery that has promoted protein.

Description

Process and equipment for recovering and treating protein in bean product wastewater

Technical Field

The invention relates to the field of wastewater treatment, in particular to a process and equipment for recovering and treating protein in bean product wastewater.

Background

At present, bean product processing industry is easy to generate polluting high-protein wastewater due to extremely complex processing contents including brewing, food processing and other production processes. For reducing the protein content in wastewater, a biochemical treatment method is generally used at present, and the protein is degraded through a series of biochemical treatments, so that the pollution can be effectively reduced. The biochemical treatment is easy to introduce a new pollution source, and the treatment period is long, so that the biochemical treatment is easily influenced by external factors. The protein in the bean product wastewater is high in content, and is high-quality nutrient with high economic value, so that the protein is degraded, which is a waste of resources.

Therefore, a process of recovering and treating proteins in wastewater by a combination of pretreatment and ultrafiltration has been developed, but the treatment effect is not satisfactory, the protein recovery rate is only about 60%, and the purity of the recovered proteins is not high, and secondary treatment is required. In addition, freeze drying and spray drying are commonly used in the current drying treatment of the protein, the energy consumption of the treatment process is high, and the structure and the activity of the protein are easily influenced.

Disclosure of Invention

Therefore, the protein recovery treatment process and the protein recovery treatment equipment for the bean product wastewater have the advantages of no influence on the structure and the activity of the protein, high recovery rate and recovery purity and low energy consumption.

The invention provides a protein recovery treatment process in bean product wastewater, which comprises the following steps:

a) performing ion exchange treatment on the bean product wastewater, and eluting an ion exchange column to obtain a first protein solution; the wastewater after the ion exchange treatment enters an MVR forced circulation system;

b) ultrafiltering the first protein solution through an ultrafiltration membrane to intercept the protein with the target molecular weight, and collecting the intercepted liquid to obtain a second protein solution;

c) vacuum evaporating and drying the second protein solution under the pressure of 7.5 kPa-12 kPa and the temperature of 40-50 ℃ to obtain a first protein solid and distillate;

d) the distillate enters the MVR forced circulation system to exchange heat with the wastewater subjected to the ion exchange treatment in the step a) to obtain preheated wastewater;

e) heating the preheated wastewater, and then carrying out flash evaporation to obtain water vapor and a third protein solution;

f) repeatedly treating the third protein solution according to the heating and flash conditions in the step e) until the mass percentage of the protein in the solution is 85-95%, so as to obtain a fourth protein solution:

g) the fourth protein solution is evaporated by vacuum drying under the pressure and temperature conditions of step c) to obtain a second protein solid.

In one embodiment, the ion exchanger used in step a) is at least one of resin, cellulose, sephadex, polyacrylamide gel, silica gel.

In one embodiment, the ultrafiltration in the step b) is performed at 5-45 ℃, the pH value is 2-12, and the pressure is 200-500 kPa.

In one embodiment, the preheated wastewater in step e) is heated at a pressure of 110kPa to 480kPa and at a temperature of 102 ℃ to 150 ℃.

In one embodiment, the elution operation in step a) comprises: adjusting the pH of the anion exchange column to 4-5 for elution; and (4) adjusting the pH value of the cation exchange column to 7-8 for elution.

In one embodiment, the ion exchange treatment in step a) requires adding a buffer solution, wherein the buffer solution is at least one of a phosphate buffer solution, a Tris-HCl buffer solution and a phosphate buffer solution, the phosphate buffer solution has a substance concentration of 0.1mol/L to 1mol/L, the Tris-HCl buffer solution has a substance concentration of 0.05mol/L to 0.1mol/L, and the phosphate buffer solution has a substance concentration of 0.05mol/L to 0.1 mol/L.

In one embodiment, the first protein solid and/or the second protein solid is cooled by condensed water, and the condensed water is mixed with the distillate in the step c) and then enters a MVR forced circulation system for exchanging heat with the wastewater after the ion exchange treatment in the step a).

In one embodiment, the preheated wastewater in step e) is heated at a flow rate of 1.5m/s to 3.0 m/s.

In one embodiment, the ultrafiltration membrane in the step b) has the specification of 10 KD-100 KD, the structure of a roll type or a tube type, and the material of the ultrafiltration membrane is at least one of polyether sulfone, polyamide and polysulfone.

In one embodiment, the pH value of the bean product wastewater in the step a) is 6-8, and the bean product wastewater is subjected to precipitation and filtration treatment in advance.

In one embodiment, the protein content in the bean product wastewater is more than 2%.

In one embodiment, the ion exchange treatment in the step a) is stopped until the protein content in the bean product wastewater is below 20g/L, and elution is carried out.

The invention realizes the recovery of protein in the bean product wastewater with high protein content by adopting the combined use of an ion exchange system, an ultrafiltration system, a vacuum drying system and an MVR forced circulation system, the recovery rate can reach more than 90 percent, and the purity of the recovered protein solid can reach more than 80 percent. Ion exchange is carried out before ultrafiltration, so that impurities in the protein can be effectively reduced, and the wastewater after the exchange treatment can enter an MVR forced circulation system for further recovery, so that the recovery rate of the protein is effectively improved; vacuum drying is carried out under the pressure of 7.5kPa to 12kPa, so that the volatilization and concentration of the protein solution can be carried out in a lower temperature range of 40 ℃ to 50 ℃, and the structure and the activity of the protein can be prevented from being damaged; the MVR forced circulation system is matched with the ion exchange system and the vacuum drying system, so that heat pollution caused by direct discharge of a large amount of steam is avoided, heat is transferred to wastewater needing further recovery and treatment, energy consumption in a recovery process is greatly reduced, the recovery rate of protein is effectively improved, the quality of treated effluent is good, the COD content can be as low as below 100mg/L, and the ammonia nitrogen content can be as low as below 10 mg/L.

In another aspect of the present invention, there is provided a process equipment for recovering and treating protein in bean product wastewater, comprising: an ion exchange system, an ultrafiltration system, a vacuum drying system and an MVR forced circulation system;

the ion exchange system comprises a feed inlet, an ion exchange column, an eluent outlet and a waste water outlet;

the eluent outlet is connected with the ultrafiltration system, and the ultrafiltration system comprises an ultrafiltration membrane and a retentate outlet;

the trapped fluid outlet is connected with the vacuum drying system, and the vacuum drying system comprises an evaporation chamber and a distillate outlet;

the MVR forced circulation system comprises a heat exchange chamber, a heating chamber and a separation chamber which are sequentially communicated; the waste water outlet and the distillate outlet are connected with the heat exchange chamber;

a liquid circulation pipeline is arranged between the bottom of the separation chamber and the heating chamber, and a steam circulation pipeline is also arranged between the upper part of the separation chamber and the heating chamber; a liquid circulation pipeline is arranged between the bottom of the separation chamber and the vacuum drying system;

wherein the ion exchange column is as defined above; the ultrafiltration membrane is defined as the ultrafiltration membrane described above.

In one embodiment, the ion exchange system further comprises a protein on-line monitoring device, and the protein on-line monitoring device is used for determining the protein content in the protein wastewater in real time.

Detailed Description

In order to facilitate an understanding of the invention, the invention will now be described more fully hereinafter with reference to the accompanying examples, in which preferred implementations of the invention are shown, but which may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the invention, "a plurality" means at least two, e.g., two, three, etc., unless explicitly specified otherwise. In the description of the present invention, "a plurality" means at least one, e.g., one, two, etc., unless specifically limited otherwise.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The invention provides a process device for recovering and treating protein in bean product wastewater, which comprises the following steps: an ion exchange system, an ultrafiltration system, a vacuum drying system and an MVR forced circulation system;

the eluent outlet is connected with an ultrafiltration system, and the ultrafiltration system comprises an ultrafiltration membrane and a trapped fluid outlet;

the trapped fluid outlet is connected with a vacuum drying system, and the vacuum drying system comprises an evaporation chamber and a distillate outlet;

in one specific example, the ion exchange system further comprises a protein on-line monitoring device, wherein the protein on-line monitoring device is used for determining the protein content in the protein wastewater in real time.

The invention also provides a protein recovery treatment process in the bean product wastewater, which comprises the following steps:

c) vacuum evaporating and drying the second protein solution under the pressure of 7.5 kPa-12 kPa and the temperature of 40-50 ℃ to obtain a first protein solid and distillate; under the pressure of 7.5 kPa-12 kPa, the boiling point of the water in the protein solution is lowered due to the reduction of the pressure, when steam with the temperature of 40-50 ℃ enters the system, the water in the protein solution is evaporated, the structure of the protein is prevented from being damaged by high temperature, the concentrated protein solution is dried, and the protein solid with the purity of more than 80 percent is obtained;

d) allowing the distillate to enter an MVR forced circulation system, and exchanging heat with the wastewater subjected to the ion exchange treatment in the step a) to obtain preheated wastewater;

f) repeatedly treating the third protein solution according to the heating and flash conditions in the step e) until the mass percentage of the protein in the solution is 85-95%, and obtaining a fourth protein solution:

g) the fourth protein solution is evaporated by vacuum drying under the pressure and temperature conditions in step c) to obtain a second protein solid.

In a specific example, the ion exchanger used in step a) is at least one of resin, cellulose, sephadex, polyacrylamide gel, silica gel; the ion exchanger is preferably ion exchange cellulose, the ion exchange cellulose has a loose hydrophilic network structure and larger surface area than other exchangers, macromolecules can freely pass through, so that the exchange capacity for biological macromolecules such as protein is larger than that of other exchangers, and the conditions of exchange and elution are mild, and the activity of the protein is not easily damaged; the anion exchange cellulose is at least one of carboxymethyl cellulose (CM-C) or Phosphocellulose (PII), preferably carboxymethyl cellulose, and when carboxymethyl is bonded on cellulose exchanger molecule, anion (cellulose-O-CH) with negative charge is formed₂-COO^-) And carry a positive chargeExchange cations for protein binding of (a); the cationic cellulose is at least one of diethylaminoethyl cellulose (DEAE-C) or crosslinked alcohol amine cellulose (ECTEOLA-C), preferably diethylaminoethyl cellulose, and when cationic group diethylaminoethyl is combined on cellulose exchanger molecule, cation is formed (cellulose-O-C)₆H₁₄N⁺H) And binds to negatively charged proteins, exchanging anions.

In a specific example, the ultrafiltration operation temperature in the step b) is 5-45 ℃, the pH value is 2-12, and the pressure is 200-500 kPa; preferably, the operation temperature is 15-25 ℃, the pH value is 6-8, and the pressure is 250-400 kPa. The proper operation temperature, pH value and pressure can make the protein be effectively trapped, and at the same time, its structure and activity can not be damaged.

In one specific example, the pressure of the preheated wastewater in the step e) is 110kPa to 480kPa during heating, and the temperature is 102 ℃ to 150 ℃; the waste water flows at high speed in the heater, exchanges heat with high-temperature steam passing through the steam compressor to heat the waste water, the pressure in the pipe is controlled to be 110 kPa-480 kPa, the pressure in the pipe is higher than the saturated steam pressure of the waste water at 102 ℃ -150 ℃, the waste water cannot boil in the pipe, after the heated waste water flows into the separation chamber, the high-temperature waste water is subjected to flash evaporation due to the sudden pressure drop to a standard atmospheric pressure (101kPa) to become a steam-liquid two phase, the steam realizes circulation through a steam circulation pipeline, and the liquid phase is converged at the bottom of the separation chamber to participate in the circulation due to gravity until the mass percentage of protein in the solution is 85% -95%.

In one specific example, the elution operation in step a) comprises: adjusting the pH value of the anion exchange column to 4-5, eluting the anion exchange column to inhibit protein anionization so as to weaken the adsorption force of the anion exchange column to an anion exchanger, wherein the regulator is at least one of hydrochloric acid, ammonium acetate or phosphate; adjusting the pH value of the cation exchange column to 7-8, eluting the cation exchange column to inhibit protein cationization so as to weaken the adsorption force of the cation exchange column to a cation exchanger, wherein the regulator is a mixture of sodium hydroxide and sodium chloride or sodium hydroxide; at the same time of elution, the ion exchange column is regenerated.

In a specific example, a buffer solution is added in the ion exchange treatment in the step a), wherein the buffer solution is at least one of a phosphate buffer solution, a Tris-HCl buffer solution and a phosphate buffer solution; further, the mass concentration of the phosphate buffer solution is 0.1 mol/L-1 mol/L; further, the mass concentration of the Tris-HCl buffer solution is 0.05 mol/L-0.1 mol/L; further, the mass concentration of the phosphate buffer solution is 0.05 mol/L-0.1 mol/L; the buffer solution is used for maintaining acid-base balance and effectively protecting normal operation of ion exchange reaction.

In one embodiment, the first protein solid and/or the second protein solid is cooled by condensed water, and the condensed water is mixed with the distillate in the step c) and then enters the MVR forced circulation system for heat exchange with the wastewater after the ion exchange treatment in the step a).

In one embodiment, the flow rate of the preheated wastewater in step e) is 1.5m/s to 3.0 m/s.

In a specific example, the ultrafiltration membrane in the step b) has the specification of 10 KD-100 KD; preferably, an ultrafiltration membrane with the molecular weight of 100 KD-200 KD is selected for the protein with the molecular weight of 100 KD-200 KD; the protein with the molecular weight of 50 KD-100 KD adopts a 50KD ultrafiltration membrane; the protein with the molecular weight of 30 KD-50 KD adopts an ultrafiltration membrane with the molecular weight of 30 KD; the protein with the molecular weight of 10 KD-30 KD adopts an ultrafiltration membrane with the molecular weight of 10 KD.

In one particular example, the ultrafiltration membrane is of a roll-to-roll or tubular construction.

In a specific example, the ultrafiltration membrane is made of at least one of polyethersulfone, polyamide and polysulfone.

In a specific example, the pH value of the bean product wastewater in the step a) is 6-8, and the pretreatment can further improve the purity of the recovered protein through precipitation and filtration.

In a specific example, the protein content in the bean product wastewater is 2% or more.

In a specific example, the ion exchange treatment in the step a) is stopped when the protein content in the bean product wastewater is below 20g/L, and preferably, when the protein content in the bean product wastewater is below 5g/L, the wastewater is stopped from being conveyed to the ion exchange system for elution.

The present invention will be described in further detail with reference to specific examples and comparative examples. It is understood that the following examples are more specific to the apparatus and materials used, and in other embodiments, are not limited thereto.

Example 1

Treating wastewater of a bean curd processing factory, wherein the main source of the wastewater is wastewater generated in the fermentation and cleaning processes, and recovering micromolecule protein and macromolecular protein in the wastewater, wherein the content of the micromolecule protein in the wastewater is 3%, the content of the macromolecular protein in the wastewater is 1%, the COD (chemical oxygen demand) is 12000mg/L, and the content of ammonia nitrogen is 250 mg/L;

and S1, pumping the wastewater into a filter box by a raw liquid pump for filtering, and feeding the filtered filtrate into a neutralization box. Adding 0.01% of sodium hydroxide into a neutralization box by using a metering pump to adjust the pH value of the wastewater to 5-6, starting a stirrer, conveying the wastewater in the neutralization box to an ion exchange system by using a lifting pump, wherein the ion exchanger is carboxymethyl cellulose, the buffer solution is phosphate buffer solution, the concentration of the phosphate buffer solution is 0.5mol/L, and the pH value of the phosphate buffer solution is 5.5;

when the protein in the wastewater is lower than 100mg/L, starting an elution system, conveying a 0.01% NaOH solution into the elution system by using a vertical pump, and maintaining the pH value at 7-8 to obtain a first protein solution;

s2, allowing the first protein solution to enter an ultrafiltration system 1, wherein the ultrafiltration system 1 uses a 50KD ultrafiltration tube to intercept and concentrate 50 KD-100 KD macromolecular proteins; the residual liquid continuously enters an ultrafiltration system 2, the ultrafiltration system 2 uses an ultrafiltration tube with 10KD to intercept and concentrate the micromolecule protein with 10 KD-50 KD to obtain a second protein solution; the operating temperature in the ultrafiltration system is 25 ℃, the pH value is 7, and the pressure is 250 kPa;

s3, allowing the second protein solution to enter a vacuum system, inputting steam at 40-50 ℃ from the outside, maintaining the pressure inside the system at about 8kPa by using a water ring vacuum pump, conveying condensed water from top to bottom, and cooling the dried protein solid;

s4, the residual liquid of the ultrafiltration system 2 and the elution system enters an MVR strong-effect circulating evaporation system, the temperature of the evaporation system is maintained at 105-110 ℃, and the pressure is maintained at 110-150 kPa;

the COD value of the final effluent is 43mg/L, the ammonia nitrogen content is 3mg/L, the protein recovery rate is 94%, and the protein solid purity is 87%.

Example 2

The protein in the low-temperature defatted soybean meal of the leaching oil plant is treated, and the protein content in the defatted soybean meal is 50%. Mixing the defatted soybean meal and water in a stock solution tank according to the proportion of 1:2, adding 0.1% NaOH solution by mass into an alkali dosing pump, adjusting the pH to about 8.0 (starting a pH instant monitor), and starting a stirrer;

s1, conveying the feed liquid to a cyclone centrifugal machine by a centrifugal pump, wherein the centrifugal pump is 1m in length³The flow rate of the flow is/h for cyclic leaching, and the leached liquid is conveyed to an ion exchange system; the ion exchanger adopts diethylaminoethyl cellulose, the buffer adopts phosphate buffer with the concentration of 0.5mol/L and the pH value of 8;

when the protein in the wastewater is lower than 5g/L, starting an elution system, conveying a 0.01% hydrochloric acid solution into the elution system by using an acid dosing pump, and maintaining the pH value at 4-5 to obtain a first protein solution;

s2, enabling the first protein solution to enter an ultrafiltration system, wherein the ultrafiltration system uses a 50KD ultrafiltration membrane to obtain a second protein solution; the operating temperature in the ultrafiltration system is 45 ℃, the pH value is 8, and the pressure is 350 kPa;

s3, allowing the second protein solution to enter a vacuum system, inputting steam at 40-50 ℃ from the outside, maintaining the pressure inside the system at about 9kPa by using a water ring vacuum pump, conveying condensed water from top to bottom, and cooling the dried protein solid;

s4, allowing residual liquid of the ultrafiltration system and the elution system to enter an MVR strong-effect circulating evaporation system, and maintaining the temperature of the evaporation system at 115-130 ℃ and the pressure at 160-200 kPa;

the COD value of the final effluent is 25mg/L, the ammonia nitrogen content is 2mg/L, the protein recovery rate is 98 percent, and the protein solid purity is 90 percent.

Example 3

Treating wastewater of a soybean treatment plant, cleaning the wastewater and producing bean curd, and recovering soybean protein in the wastewater, wherein the COD in the wastewater is 11740mg/L, the ammonia nitrogen content is 59mg/L, and the soybean protein content is 2.5%;

s1, conveying the wastewater subjected to filtering and precipitation pretreatment to an ion exchange system, wherein the ion exchanger is diethyl aminoethyl cellulose, the buffer solution is phosphate buffer solution with the concentration of 0.0175mol/L and the pH of 6.7;

when the protein in the wastewater is lower than 50mg/L, starting an elution system, conveying a 0.01% hydrochloric acid solution into the elution system by using a vertical pump, and maintaining the pH value at 4-5 to obtain a first protein solution;

s2, allowing the first protein solution to enter an ultrafiltration system, wherein the ultrafiltration system uses a 50KD ultrafiltration tube to intercept and concentrate proteins to obtain a second protein solution; the operating temperature in the ultrafiltration system is 5 ℃, the pH value is 6, and the pressure is 300 kPa;

s3, allowing the second protein solution to enter a vacuum system, inputting steam at 40-50 ℃ from the outside, maintaining the pressure inside the system at about 11kPa by using a water ring vacuum pump, conveying condensed water from top to bottom, and cooling the dried protein solid;

s4, allowing residual liquid of the ultrafiltration system and the elution system to enter an MVR strong-effect circulating evaporation system, and maintaining the temperature of the evaporation system at 135-140 ℃ and the pressure at 300-400 kPa;

the COD value of the final effluent is 58mg/L, the ammonia nitrogen content is 3mg/L, the protein recovery rate is 98 percent, and the protein solid purity is 82 percent.

Example 4

and S1, pumping the wastewater into a filter box by a raw liquid pump for filtering, and feeding the filtered filtrate into a neutralization box. Adding 0.01% of sodium hydroxide into a neutralization box by using a metering pump to adjust the pH value of the wastewater to 5-6, starting a stirrer, conveying the wastewater in the neutralization box to an ion exchange system by using a lifting pump, wherein the ion exchanger is sephadex G-100, the buffer is Tris-HCl buffer with the concentration of 0.08mol/L and the pH value of 5;

the COD value of the final effluent is 89mg/L, the ammonia nitrogen content is 8mg/L, the protein recovery rate is 90%, and the protein solid purity is 81%.

Example 5

and S1, pumping the wastewater into a filter box by a raw liquid pump for filtering, and feeding the filtered filtrate into a neutralization box. Adding 0.01% of sodium hydroxide into a neutralization box by using a metering pump to adjust the pH value of the wastewater to 5-6, starting a stirrer, conveying the wastewater in the neutralization box to an ion exchange system by using a lifting pump, wherein an ion exchanger is weakly-alkaline styrene anion exchange resin, a buffer solution is Tris-HCl buffer solution, the concentration of the Tris-HCl buffer solution is 0.03mol/L, and the pH value of the Tris-HCl buffer solution is 5.9;

the COD value of the final effluent is 76mg/L, the ammonia nitrogen content is 6mg/L, the protein recovery rate is 91 percent, and the protein solid purity is 82 percent.

Comparative example 1

Treating the waste water of the plum fruit wine factory, wherein the main source of the waste water is waste water generated in the fermentation and preparation processes, and recovering single-cell protein in the waste water, wherein the COD in the waste water is 13204mg/L, the ammonia nitrogen content is 178mg/L, and the protein content is 3.9%;

s1, pumping the wastewater into a filter box by a raw liquid pump for filtering, enabling filtered filtrate to enter a neutralization box, adding 0.01% of sodium hydroxide into the neutralization box by using a metering pump, adjusting the pH value of the wastewater to 5-6, starting a stirrer, conveying the wastewater in the neutralization box to an ion exchange system by using a lifting pump, wherein the ion exchanger is carboxymethyl cellulose, the buffer solution is phosphoric acid buffer solution, the concentration of the buffer solution is 0.5mol/L, and the pH value of the buffer solution is 5.5;

the COD value of the final effluent is 48mg/L, the ammonia nitrogen content is 4mg/L, the protein recovery rate is 60 percent, and the protein solid purity is 72 percent.

Comparative example 2

The protein is recovered and treated by a water treatment device of a bean curd factory by adopting a pretreatment and ultrafiltration method, the COD of raw water is 14200 mg/L-14920 mg/L, the ammonia nitrogen content is 483 mg/L-571 mg/L, and the protein content is 11.7%. Ultrafiltering the treated solution after primary precipitation and filtration treatment by a 50KD ultrafiltration membrane; the COD of the effluent is 580 mg/L-610 mg/L, the ammonia nitrogen content is about 200mg/L, and the protein recovery rate is 57%.

The COD value of the treated wastewater is low, the ammonia nitrogen content is low, and the protein recovery rate and the purity of the recovered protein are high; in comparative example 1, when the process of the invention is used for treating other kinds of protein-containing wastewater, the COD value and the ammonia nitrogen content are both obviously reduced, but the properties of the protein in the plum fruit wine are different from those of the protein in the bean product, so the recovery treatment effect on the plum fruit wine is not ideal, and the recovery rate and the purity are not high; comparative example 2 does not undergo ion exchange and vacuum drying, the COD value and ammonia nitrogen content of the treated effluent cannot reach the standard, and secondary treatment is needed; the recovery rate of the protein is low, and the content of protein impurities obtained by recovery is high.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A process for recovering and treating protein in bean product wastewater is characterized by comprising the following steps:

2. The process of claim 1, wherein the ion exchanger used in step a) is at least one of resin, cellulose, sephadex, polyacrylamide gel, and silica gel.

3. The process according to claim 1, wherein the ultrafiltration in step b) is carried out at an operating temperature of 5 ℃ to 45 ℃, a pH of 2 to 12 and a pressure of 200kPa to 500 kPa.

4. The process of claim 1, wherein the preheated wastewater in step e) is heated at a pressure of 110kPa to 480kPa and at a temperature of 102 ℃ to 150 ℃.

5. The process according to claim 1, wherein the elution in step a) comprises: adjusting the pH of the anion exchange column to 4-5 for elution; and (4) adjusting the pH value of the cation exchange column to 7-8 for elution.

6. The process according to any one of claims 1 to 5, wherein a buffer solution is added in the ion exchange treatment in step a), the buffer solution is at least one of a phosphate buffer solution, a Tris-HCl buffer solution and a phosphate buffer solution, the substance concentration of the phosphate buffer solution is 0.1mol/L to 1mol/L, the substance concentration of the Tris-HCl buffer solution is 0.05mol/L to 0.1mol/L, and the substance concentration of the phosphate buffer solution is 0.05mol/L to 0.1 mol/L.

7. The treatment process according to any one of claims 1 to 5, wherein the first protein solid and/or the second protein solid is cooled by condensed water, and the condensed water is mixed with the distillate in the step c) and then enters an MVR forced circulation system for heat exchange with the wastewater after the ion exchange treatment in the step a).

8. The process according to any one of claims 1 to 5, wherein the preheated wastewater in step e) is heated at a flow rate of 1.5m/s to 3.0 m/s.

9. The treatment process according to any one of claims 1 to 5, wherein the ultrafiltration membrane in the step b) has a specification of 10 KD-100 KD, a structure of a roll type or a tube type, and a material of the ultrafiltration membrane is at least one of polyether sulfone, polyamide and polysulfone.

10. The treatment process according to any one of claims 1 to 5, wherein the pH of the bean product wastewater in the step a) is 6 to 8, and the bean product wastewater is subjected to precipitation and filtration treatment in advance.

11. The treatment process according to any one of claims 1 to 5, wherein the protein content in the bean product wastewater is 2% or more.

12. The treatment process according to any one of claims 1 to 5, wherein the ion exchange treatment in step a) is stopped until the protein content in the soybean wastewater is 20g/L or less, and then the elution is carried out.

13. A protein recovery processing process equipment in bean product wastewater is characterized by comprising the following steps: an ion exchange system, an ultrafiltration system, a vacuum drying system and an MVR forced circulation system;

wherein the ion exchange column is as defined in claim 1 or 2; the ultrafiltration membrane is as defined in claim 1 or 9.

14. The apparatus of claim 13, wherein the ion exchange system further comprises an online protein monitoring device for determining the protein content of the protein wastewater in real time.