An on-line pH adjustment system for rice slurry

Abstract

This invention provides an online pH adjustment system for rice slurry, aiming to solve the problems of long pH adjustment time, high reagent consumption, and untimely reaction termination in existing technologies. Specifically, it includes a reaction tank, a transfer pump, a pre-installed automatic regulating valve, a flow meter, a pH adjustment unit, a mixing unit, and a closed-loop control unit. After the rice slurry is adjusted to the acceptable pH level by the pH adjustment unit, it is output to the next stage via the closed-loop control unit. Unacceptable slurry is returned to the reaction tank via the closed-loop control unit. This invention significantly improves the speed and accuracy of pH adjustment through a two-stage pH adjustment system and automatic control technology. The system can complete the pH adjustment of the material within 15-20 seconds and the pH adjustment of the entire reaction tank within 10 minutes, ensuring timely termination of the enzymatic hydrolysis reaction.

Description

Technical Field

[0001] This utility model relates to the technical field of rice starch processing equipment, and in particular to an online pH adjustment system for rice slurry. Background Technology

[0002] Rice starch is a novel plant starch extracted from rice. It has excellent properties such as small particle size, white color, easy digestibility, and low allergenicity, and is widely used in the food industry. However, the small particle size of rice starch (approximately 3-5 μm) and the small difference in particle size between rice starch and rice protein make it more difficult to separate and prepare.

[0003] Traditional rice starch production processes employ enzymatic methods, using proteases, cellulases, and lipases to break the bonds between rice starch and proteins, fibers, and fats. This is followed by physical separation (such as hydrocyclone washing) to separate the starch from other components. After the enzymatic reaction is complete, it needs to be terminated to proceed to the next step. Traditional methods typically involve heating to inactivate the enzymes; however, because rice starch is prone to gelatinization, this method is unsuitable. Therefore, pH adjustment is used to terminate the reaction.

[0004] In existing technologies, pH adjustment is achieved by adding acid or alkali solutions to the reaction vessel. However, due to the large volume of the reaction vessel, it takes a long time for the acid or alkali solution to mix evenly with the materials, and the pH value continues to decrease during enzymatic hydrolysis, resulting in an adjustment time of more than 30 minutes, making it impossible to terminate the reaction in time, and increasing the consumption of acid and alkali reagents. Utility Model Content

[0005] This application addresses the shortcomings of the prior art by providing an online pH adjustment system for rice slurry, which solves the problems of long pH adjustment time, large reagent consumption, and untimely reaction termination in the prior art.

[0006] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows:

[0007] An online pH adjustment system for rice slurry includes, in sequence, a reaction tank, a delivery pump, a pre-installed automatic regulating valve, a flow meter, a pH adjustment unit, a mixing unit, and a closed-loop control unit. After the rice slurry is adjusted to the required pH by the pH adjustment unit, it is output to the next stage through the closed-loop control unit. Unqualified slurry is returned to the reaction tank through the closed-loop control unit.

[0008] Furthermore, the pH adjustment unit includes:

[0009] The first adjustment module consists of a first automatic regulating valve, a first check valve, a first reagent addition tube, and a first pH meter. The first automatic regulating valve dynamically adjusts the amount of acid and alkali reagents added according to the detection value of the first pH meter to complete the first-stage adjustment of the target pH value.

[0010] The second adjustment module consists of a second automatic regulating valve, a second check valve, a second reagent addition tube, and a second pH meter. The second automatic regulating valve dynamically adjusts the amount of acid and alkali reagents added based on the detection value of the second pH meter to complete the secondary adjustment of the target pH value.

[0011] Furthermore, the drive unit of the reaction vessel is equipped with a PLC controller, the tank body is equipped with a level gauge and a tank pH meter, and the bottom of the reaction vessel is equipped with an automatic bottom valve.

[0012] Furthermore, the closed-loop control unit includes:

[0013] An automatic three-way valve is installed at the final outlet of the pH adjustment module. Based on the pH value detected by the final pH meter, materials with pH values ​​that do not meet the standard are returned to the reaction tank.

[0014] The PLC controller is installed on the reaction tank to receive feedback signals from the level gauge, tank pH meter and flow meter in real time, and dynamically control the opening and closing status of the transfer pump, various automatic regulating valves and automatic three-way valves.

[0015] Furthermore, the mixing unit includes a first mixing tube and a second mixing tube, each of which is equipped with an impeller.

[0016] Furthermore, the flow rate of the delivery pump is configured such that the hourly delivery capacity is greater than 6 times the effective volume of the reaction vessel.

[0017] Furthermore, the acid and alkali solution inlet of the reagent addition tube is set at an angle of 30° to 60° to the flow direction of the rice slurry to reduce flow resistance and enhance turbulent mixing effect.

[0018] Furthermore, the PLC controller has a built-in liquid level protection program. When the liquid level gauge detects that the liquid level in the reaction tank is lower than 10% of the total liquid level, it will forcibly switch the automatic three-way valve to the closed-loop reflux mode until the pH value detected by the tank pH meter reaches the standard.

[0019] The advantages of this utility model over the prior art are as follows:

[0020] This invention significantly improves the speed and accuracy of pH adjustment through a two-stage pH adjustment system. The system can complete the pH adjustment of materials within 15-20 seconds and the pH adjustment of the entire reaction vessel within 10 minutes, ensuring timely termination of the enzymatic hydrolysis reaction. Compared to traditional methods, this technology reduces the pH adjustment time from 35 minutes to 9 minutes, while also reducing the amount of acid and alkali reagents used, lowering the ash content of the product, and improving production efficiency and product quality. Furthermore, the system ensures the stability and accuracy of pH adjustment through an automatic three-way valve and closed-loop control, avoiding material waste and process fluctuations. Attached Figure Description

[0021] Figure 1 This is a system block diagram of the present invention.

[0022] The components include: 1. Reaction tank; 2. PLC controller; 3. Level gauge; 4. Tank pH meter; 5. Automatic tank bottom valve; 6. Transfer pump; 7. Pre-installed automatic regulating valve; 8. Flow meter; 9. First automatic regulating valve; 10. Check valve; 11. First reagent addition tube; 12. First mixing tube; 13. First pH meter; 14. Second automatic regulating valve; 15. Second check valve; 16. Second reagent addition tube; 17. Second mixing tube; 18. Second pH meter; 19. Automatic three-way valve. Detailed Implementation

[0023] The specific embodiments of this utility model are described below with reference to the accompanying drawings.

[0024] This invention provides an online pH adjustment system for rice slurry and a pH adjustment method based on the system, aiming to solve the problems of long pH adjustment time, large reagent consumption, and untimely reaction termination in the prior art.

[0025] like Figure 1 As shown, in one embodiment of this utility model, rice slurry undergoes enzymatic hydrolysis in reaction tank 1, level gauge 3 can monitor the real-time liquid level in reaction tank 1, and tank pH meter 4 can monitor the real-time pH value in reaction tank.

[0026] In one embodiment of this utility model, when the rice slurry reaches the reaction endpoint, the automatic tank bottom valve 5 opens, and the material is transported from the reaction tank 1 through the conveying pump 6. The regulating valve is opened to the set opening degree, and the rice slurry is transported at the set flow rate.

[0027] In one embodiment of this invention, to ensure the accuracy of the adjustment and minimize errors, the pH adjustment is performed in two stages. The first stage involves the acid / alkali solution passing through the first automatic regulating valve 9 and the first check valve 10, then entering the first reagent addition tube 11 at a certain angle to mix with the rice slurry. The first automatic regulating valve 9 is linked to the detection value of the first pH meter 13, automatically adjusting its opening degree according to the value of the first pH meter 13. The first check valve 10 prevents material from backflowing into the acid / alkali reagent pipeline. The angled entry of the acid / alkali solution into the first reagent addition tube 11 reduces entry resistance. This completes the first stage of pH adjustment (80%).

[0028] In one embodiment of this invention, the second stage of pH adjustment involves the acid / alkali solution passing through a second automatic regulating valve 14 and a second check valve 15, then entering the second reagent addition tube 16 at a certain angle to mix with the rice slurry. The second automatic regulating valve 14 is linked to the detection value of the second pH meter 18, automatically adjusting its opening degree according to the value of the second pH meter 18; the second check valve 15 prevents material from backflowing into the acid / alkali reagent pipeline; and the angled entry of the acid / alkali solution into the second reagent addition tube 16 reduces entry resistance. This completes the first stage of pH adjustment (20%).

[0029] In one embodiment of this utility model, the first mixing tube 12 and the second mixing tube 17 are designed with a certain volume. The rice slurry needs a certain amount of time to pass through. There is an impeller in the tube. The slurry after the acid and alkali solutions and rice slurry are mixed can be fully mixed after passing through the first mixing tube 12 to ensure that the pH value reaches a relatively stable state.

[0030] In one embodiment of this utility model, the rice slurry with adjusted pH value is detected by a second pH meter 18. When the pH value reaches the set value, the material enters the next process through an automatic three-way valve 19; otherwise, it is transported back to the reaction tank 1. This ensures that the material with a qualified pH value (within ±0.1 of the set value) enters the next process for processing.

[0031] In one embodiment of this utility model, the PLC controller displays parameters such as pH value, motor running status, and valve opening status in real time, and controls the operation of the system.

[0032] Step S1: Set system parameters with an initial pH value of P0, a first-stage target pH value of P1, and a second-stage target pH value of P2, where P2 is the target control value. The relationship between the three is: P1 = P0 + (P2 - P0) * 80%, P2 = P0 + (P2 - P0) * 20%; Set the flow rate value F, where the value of F is greater than 6 times the effective volume of the reaction tank. This value determines the opening degree of the pre-installed automatic regulating valve 7 to accurately control the flow rate.

[0033] Step S2: When the rice slurry in reaction tank 1 reaches the reaction endpoint, the system starts, the pH meter 4 in the tank detects and displays the initial pH value P0, the automatic bottom valve 5 opens, the material is conveyed by the conveying pump 6, the regulating valve 8 opens to the set opening degree, and the rice slurry is conveyed at the set flow rate F.

[0034] Step S3: First-stage pH adjustment. The rice slurry flows through the pipe, and the acid / alkaline solution passes through the first automatic regulating valve 9 and the first check valve 10, then enters the first reagent addition tube 11 to mix with the rice slurry. The first automatic regulating valve 9 is linked to the detection value of the first pH meter 13, automatically adjusting its opening degree according to the value of the first pH meter 13, which is P1. This completes the first-stage pH adjustment (80%).

[0035] Step S4: Second stage pH adjustment: The acid-base solution passes through the second automatic regulating valve 14 and the second check valve 15, and then enters the second reagent addition tube 16 at a certain angle to mix with the rice slurry. The second automatic regulating valve 14 is linked to the detection value of the second pH meter 18, and automatically adjusts the opening degree according to the value of the second pH meter 18. The value of the first pH meter 13 is P2.

[0036] Step S5: In the initial stage of system startup, the automatic tank bottom valve 5 is opened and the transfer pump 6 is started. The flow rate F has a process from 0 to the set value. At this time, the flow rate is variable and the pH value adjustment may have errors. Therefore, the rice slurry is detected by the second pH meter 18. When the pH value reaches the set value, the three-way valve 19 is designed. The material with qualified pH value (within the range of P2±0.1) enters the next process through the automatic three-way valve 19. Otherwise, it is transported back to the reaction tank 1 to ensure that the material with qualified pH value enters the next process for processing.

[0037] Step S6: In the later stages of system operation, when the material in the reaction tank is low, the flow rate L goes through a process from the set value to 0. Therefore, the pH adjustment will also fluctuate significantly. Moreover, as the material level drops, a vortex may form at the pump inlet, allowing air to enter and causing large flow fluctuations. To avoid flow fluctuations, this system is designed so that when the liquid level L is below 10% of the total liquid level, the automatic three-way valve 19 is set to return the material to reaction tank 1, forming a closed-loop pH adjustment. When the pH is adjusted to the set value, i.e., the pH meter 4 in the tank shows that the set value has been reached, the automatic three-way valve opens again to deliver the material to the next stage, completing the pH adjustment.

[0038] Experimental data:

[0039] Control group: Adjustments were made in a reaction vessel with an effective volume of 5 m³, containing 5 m³ of rice slurry with a concentration of 20%. The reaction temperature was 50℃, and the initial pH of the material was 6.6. Neutral protease, lipase, and cellulase were added for a complex enzymatic hydrolysis reaction. After approximately 5 hours, the reaction was considered complete, and the pH of the material dropped to 5.6. A 10% NaOH solution was then added to adjust the pH to 9.5, at which point enzyme activity was largely inhibited. The reaction vessel was kept agitated, and NaOH solution was continuously added to ensure thorough mixing of the alkali solution and rice slurry. The pH was monitored continuously until it reached 9.5 ± 0.1, at which point the adjustment was complete. The entire pH adjustment process took 35 minutes and involved the addition of 82 kg of 10% NaOH solution.

[0040] Experimental Group: The pH value was adjusted online. The effective volume of the reaction tank was 5 m³, filled with 5 m³ of rice slurry at a concentration of 20%. The reaction temperature was 50℃, and the initial pH value of the material was 6.6. The same amounts of neutral protease, lipase, and cellulase as the control group were added for a complex enzymatic hydrolysis reaction. After approximately 5 hours, the reaction was considered complete, and the pH value of the material dropped to 5.6. On the PLC control cabinet, P2 was set to 9.5, with an allowable error of 0.1, and the flow rate F was set to 35 m³ / h. The device was started, and pH adjustment began. The concentration of the added NaOH solution was also 10%. When the pH value of all the liquid in the reaction tank was adjusted, the time taken was 9 minutes, and the amount of 10% NaOH solution added was 68 kg, a reduction of 14 kg compared to the experimental group. This shows that the reaction time was significantly shortened, and the addition of alkali solution was reduced, thus lowering the ash content of the product.

[0041] This utility model patent provides an online pH adjustment device system and its usage method for rapidly terminating the enzymatic hydrolysis reaction of rice slurry. Through a two-stage pH adjustment system and automatic control technology, the speed and accuracy of pH adjustment are significantly improved. The system can complete the pH adjustment of the material within 15-20 seconds and the pH adjustment of the entire reaction tank within 10 minutes, ensuring timely termination of the enzymatic hydrolysis reaction. Compared with traditional methods, this technology reduces the pH adjustment time from 35 minutes to 9 minutes, while reducing the amount of acid and alkali reagents used (e.g., reducing NaOH solution by 14 kg), lowering the ash content of the product, and improving production efficiency and product quality. Furthermore, the system ensures the stability and accuracy of pH adjustment through an automatic three-way valve and closed-loop control, avoiding material waste and process fluctuations.

[0042] The above description is an explanation of the present utility model and not a limitation thereof. The scope of the present utility model is defined by the claims. Within the protection scope of the present utility model, any form of modification can be made.

Claims

1. An online pH adjustment system for rice slurry, characterized in that: The system includes, in sequence, a reaction tank (1), a delivery pump (6), a pre-installed automatic regulating valve (7), a flow meter (8), a pH adjustment unit, a mixing unit, and a closed-loop control unit. The rice slurry is adjusted to the required pH level by the pH adjustment unit and then output to the next stage through the closed-loop control unit. The unqualified slurry is returned to the reaction tank (1) through the closed-loop control unit. The pH adjustment unit includes: The first adjustment module consists of a first automatic regulating valve (9), a first check valve (10), a first reagent addition tube (11), and a first pH meter (13). The first automatic regulating valve (9) dynamically adjusts the amount of acid and alkali reagents added according to the detection value of the first pH meter (13) to complete the first-stage adjustment of the target pH value. The second adjustment module consists of a second automatic regulating valve (14), a second check valve (15), a second reagent addition tube (16), and a second pH meter (18). The second automatic regulating valve (14) dynamically adjusts the amount of acid and alkali reagents added according to the detection value of the second pH meter (18) to complete the secondary adjustment of the target pH value.

2. The online pH adjustment system for rice slurry as described in claim 1, characterized in that: The driving part of the reaction tank (1) is equipped with a PLC controller (2), the tank body of the reaction tank (1) is equipped with a level gauge (3) and a tank pH meter (4), and the bottom of the reaction tank (1) is equipped with an automatic bottom valve (5).

3. The online pH adjustment system for rice slurry as described in claim 2, characterized in that: The closed-loop control unit includes: An automatic three-way valve (19) is installed at the final outlet of the pH adjustment module. It returns materials whose pH does not meet the standard to the reaction tank (1) according to the detection value of the final pH meter. The PLC controller (2) is installed on the tank body of the reaction tank (1) to receive feedback signals from the level gauge (3), the tank pH meter (4) and the flow meter (8) in real time, and dynamically control the opening and closing status of the delivery pump (6), each automatic regulating valve and the automatic three-way valve (19).

4. The online pH adjustment system for rice slurry as described in claim 1, characterized in that: The mixing unit includes a first mixing tube (12) and a second mixing tube (17), and each mixing tube is equipped with an impeller.

5. The online pH adjustment system for rice slurry as described in claim 1, characterized in that: The flow rate of the delivery pump (6) is configured such that the hourly delivery volume is greater than 6 times the effective volume of the reaction vessel (1).

6. The online pH adjustment system for rice slurry as described in claim 1, characterized in that: The acid and alkali solution inlet of each reagent addition tube is set at an angle of 30° to 60° to the direction of rice slurry flow.

7. The online pH adjustment system for rice slurry as described in claim 2, characterized in that: The PLC controller (2) has a built-in liquid level protection program. When the liquid level gauge (3) detects that the liquid level of the reaction tank (1) is lower than 10% of the total liquid level, it will forcibly switch the automatic three-way valve (19) to the closed-loop reflux mode until the pH value detected by the tank pH meter (4) meets the standard.

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