Continuous acid hydrolysis device for lactic acid production and continuous acid hydrolysis method

Abstract

The present invention relates to the technical field of lactic acid production by calcium salt fermentation, and discloses a continuous acid hydrolysis device for lactic acid production, comprising a barrel, wherein a raw material zone, a mixing zone, and a heat exchange zone are arranged at the upper portion of the barrel, a feed port is arranged between the raw material zone and the mixing zone, and a liquid discharge port is arranged between the mixing zone and the heat exchange zone; a first stirring unit is arranged in the mixing zone, a liquid supply hose is passed through the center of the main stirring rod of the first stirring unit, and sulfuric acid in the liquid supply hose is sprayed out from a first nozzle arranged on a first stirring blade; a pH electrode is arranged in the mixing zone; an acid hydrolysis zone is arranged at the lower portion of the barrel, and a liquid supply pipe is connected between the heat exchange zone and the acid hydrolysis zone. The present invention also discloses a method for continuous acid hydrolysis using the above-mentioned device, comprising: the raw fermentation liquid enters the mixing zone from the raw material zone to be mixed with sulfuric acid, then enters the heat exchange zone, and finally enters the acid hydrolysis zone. The device has a simple structure, a high degree of automation, and is cost-effective. The method has excellent acid hydrolysis effect and significantly reduces costs.

Description

Technical Field

[0001] The present invention relates to the technical field of preparing lactic acid by calcium salt fermentation, and in particular to a continuous acid hydrolysis device for lactic acid production and a continuous acid hydrolysis method. Background Art

[0002] In the existing calcium salt method for lactic acid fermentation, the fermentation broth after bacterial separation is fed via centrifugal pumps to each of the acid hydrolysis tanks in the acid hydrolysis process. Sulfuric acid is then pumped into the tanks using a sulfuric acid pump. pH electrodes installed in the tanks measure the pH of the solution to determine whether it has reached the isoelectric point. Due to the large size of the acid hydrolysis tanks, the sulfuric acid reacts violently with the calcium lactate in the fermentation broth, necessitating strict control over the rate of sulfuric acid addition. From the start of sulfuric acid addition to the completion of the acid hydrolysis reaction, the pH of the solution takes a long time to reach the isoelectric point.

[0003] like Figure 1 As shown, the existing acidolysis tank includes an acid supply pipeline 1, a raw material pipeline 2, an acidolysis tank 3, a stirring unit 4, a heat exchange unit 5 and a liquid outlet 6. For large-scale production, the total volume of the acidolysis tanks required is huge. In other words, a large number of acidolysis tanks are required, and each acidolysis tank needs to be equipped with a pH electrode, a sulfuric acid pipeline and a sulfuric acid automatic control valve, and a stirring device is installed. Moreover, the acidolysis process is an exothermic reaction, and all acidolysis tanks need to be designed with an external accompanying pipe cooler, and circulating water is introduced into the external accompanying pipe cooler to take away the heat of the reaction process. The above-mentioned acidolysis process requires a large number of acidolysis tanks, and each acidolysis tank needs to be equipped with multiple auxiliary units, which leads to an increase in the production cost and maintenance cost of the acidolysis process in the existing lactic acid production.

[0004] CN209123891U discloses a continuous acid hydrolysis reaction device for lactic acid production, comprising: an acid hydrolysis reactor, a mixing reactor, a solid-liquid separator, a post-processing reactor, a liquid storage tank, and a recovery device. The acid hydrolysis reactor is provided with a calcium lactate feed port and a sulfuric acid feed port, as well as a first pipeline connected to the mixing reactor; the mixing reactor is connected to the solid-liquid separator and then to the post-processing reactor, and a conveying device is provided in the post-processing reactor, and its discharge port is connected to the recovery device; the liquid storage tank is connected to the solid-liquid separator and the post-processing reactor respectively. Although this patent also uses a pH sensor to detect the pH value of the feed liquid, its result is only real-time feedback to the operator, and the operator controls the flow rate of sulfuric acid according to requirements. This method does not add sulfuric acid in a timely manner, and the accuracy of manual control is low, making it difficult to accurately adjust the pH value of the mixed solution.

[0005] CN112958026A discloses a continuous acid hydrolysis reaction device for lactic acid production, comprising an acid hydrolysis reaction barrel and a mixing reaction barrel, wherein the acid hydrolysis device is connected to the middle of the upper end of the acid hydrolysis reaction barrel, the mixing device is connected to the middle of the upper end of the mixing reaction barrel, the lower ends of the acid hydrolysis reaction barrel and the lower ends of the mixing reaction barrel are fixedly connected to three support rods, the lower ends of the six support rods are fixedly connected to a base, the upper right end of the base is fixedly connected to a separation barrel, the left and right walls of the separation barrel are movably connected to the separation device, the middle of the lower end of the acid hydrolysis reaction barrel is connected to a first connecting pipe, and the middle of the lower end of the mixing reaction barrel is connected to a second connecting pipe. This patent sets up multiple devices, occupies a large area, and the mixing of sulfuric acid and raw material liquid in the acid hydrolysis device still adopts the method of directly adding sulfuric acid to the raw material liquid, which limits the mixing speed and takes a long mixing time.

[0006] Existing patents reveal that sulfuric acid is still directly added to the raw liquid during the mixing process. This method limits the rate of sulfuric acid addition and increases the mixing time of the two liquids. For large-scale production, due to the long mixing time, in order to achieve the required production efficiency, more acid hydrolysis tanks and corresponding auxiliary facilities must be added, which inevitably leads to increased equipment and facility investment.

[0007] In addition, in controlling the addition of sulfuric acid, a pH sensor is used to detect the pH value of the mixed liquid, and the operator manually adds sulfuric acid for adjustment based on the measured pH value. This method has a certain hysteresis, and it is difficult to achieve accurate and timely adjustment of the pH value of the mixed liquid during the mixing process. Summary of the Invention

[0008] The present invention aims to overcome one of the shortcomings of the prior art by providing a continuous acid hydrolysis apparatus for lactic acid production and a method for continuous acid hydrolysis using the apparatus. The apparatus enables precise and timely addition of sulfuric acid to adjust the pH value in large-scale industrial lactic acid production. Furthermore, the apparatus can reduce the number of acid hydrolysis tanks used, thereby reducing the number of auxiliary units required for the acid hydrolysis tanks, thereby lowering production costs and equipment maintenance costs.

[0009] The present invention is achieved through the following technical solutions:

[0010] A continuous acid hydrolysis device for lactic acid production, comprising a barrel body, the barrel body being divided into upper and lower parts by a partition;

[0011] The upper part of the barrel is provided with a raw material area, a mixing area and a heat exchange area, a feed port is provided between the raw material area and the mixing area, and a liquid discharge port is provided between the mixing area and the heat exchange area;

[0012] A first stirring unit is provided in the mixing area, a liquid supply hose is passed through the center of the main stirring vertical rod of the first stirring unit, the liquid supply hose is connected to the infusion tube inside the first stirring horizontal rod of the first stirring unit, the infusion tube is connected to the first stirring blade of the first stirring unit, and a first nozzle is provided on the first stirring blade;

[0013] A pH electrode 1 is provided in the mixing zone, and the pH electrode 1, the liquid supply hose and the first stirring unit are all controlled by a control system;

[0014] An acid decomposition zone is arranged at the lower part of the barrel body, and a liquid supply pipe is connected between the heat exchange zone and the acid decomposition zone.

[0015] Furthermore, a mixing zone is provided at the center of the upper portion of the barrel body, and other areas are raw material zones and heat exchange zones. The raw material zone is located above the heat exchange zone, a feed port is provided at the lower end of the raw material zone near the mixing zone, and a drain port is provided at the middle of the side wall of the mixing zone and below the partition between the raw material zone and the heat exchange zone.

[0016] Preferably, the liquid supply port is evenly arranged along the outer wall of the mixing zone, the liquid discharge port is evenly arranged along the outer wall of the mixing zone, an electronic valve is provided on the material supply port, and a baffle is provided on the liquid discharge port;

[0017] Preferably, the heat exchange zone is provided with heat exchange tubes, the inlet and outlet of the heat exchange tubes are provided on the side wall of the heat exchange zone, and the heat exchange tubes are provided in multiple groups and are evenly distributed in the heat exchange zone space;

[0018] Preferably, an electronic valve is provided at one end of the liquid supply pipeline close to the heat exchange zone, and a check valve is provided at one end of the liquid supply pipeline close to the acidolysis zone, and the electronic valve is controlled by a control system;

[0019] Preferably, a second nozzle is provided on the first stirring bar of the first stirring unit;

[0020] Preferably, multiple overflow ports are provided at a position above 2 / 3 of the height of the acidolysis zone, and an electronic valve is provided at each overflow port. A pH electrode 2 is provided in the acidolysis zone near the liquid supply pipe port and the overflow port, respectively. The electronic valve is controlled by a control system, and the pH electrode 1, pH electrode 2, the first stirring unit and the liquid supply hose are controlled in a linkage manner through the control system.

[0021] Furthermore, a second stirring unit is provided in the acidolysis zone, and the second stirring unit shares the main stirring rod of the first stirring unit, the lower end of the main stirring rod passes through the center of the partition, and the upper end of the main stirring rod passes through the barrel and is fixed on the first drive;

[0022] Preferably, a third nozzle is provided on the second stirring blade of the second stirring unit, and a fourth nozzle is provided on the second stirring cross bar of the second stirring unit.

[0023] Furthermore, a spiral rod with a hollow center is provided on the periphery of the main stirring rod of the first stirring unit, the main stirring rod passes through the hollow center of the spiral rod, the upper end of the spiral rod passes through the barrel and is fixed on the second drive, and a first connecting mechanism is provided between the two ends of the spiral rod and the main stirring rod, the first connecting mechanism being used to control the connection and disconnection of the spiral rod and the main stirring rod;

[0024] Preferably, the lower end of the spiral rod reaches the bottom surface of the mixing zone but does not pass through the partition;

[0025] Preferably, the first drive and the second drive are both motors and are controlled by a control system.

[0026] Furthermore, the first connecting mechanism includes a fixed block arranged on the inner wall of the spiral rod, a connecting rod is arranged at the front end of the fixed block, an arc-shaped plate is arranged at the front end of the connecting rod, and a blocking block is arranged at the other end of the connecting rod. The blocking block is connected to one end of a spring on the side away from the arc-shaped plate, and the other end of the spring is fixed on the fixed block or the inner wall of the spiral rod. The area of the main stirring rod close to the arc-shaped plate is made of electromagnetic material, and the presence or absence of magnetism in this area is controlled by the control system.

[0027] Furthermore, a hollow lifting slide rod is provided on the periphery of the spiral rod, the spiral rod passes through the hollow middle of the lifting slide rod, and a second connecting mechanism is provided between the two ends of the lifting slide rod and the spiral rod, and the second connecting mechanism is used to control the connection and separation of the lifting slide rod and the spiral rod;

[0028] Preferably, an external thread is provided on the outer wall of the spiral rod, and an internal thread which engages with the external thread is provided on the inner wall of the lifting slide rod.

[0029] Furthermore, a lifting plate is provided at the bottom of the mixing zone, the edge of the lifting plate is in close contact with the inner wall of the mixing zone, the lifting slide rod, the spiral rod and the main stirring rod all pass through the center of the lifting plate and are connected with waterproof sealed bearings, and the pH electrode is provided on the lifting plate.

[0030] Furthermore, the second connecting mechanism includes a second fixed block arranged on the inner wall of the lifting slide rod, a second connecting rod is arranged at the front end of the second fixed block, a second arc plate is arranged at the front end of the second connecting rod, and a second blocking block is arranged at the other end of the second connecting rod. The second blocking block is connected to one end of a second spring on the side away from the second arc plate, and the other end of the second spring is fixed to the second fixed block or the inner wall of the lifting slide rod. The area of the spiral rod close to the second arc plate is made of electromagnetic material, and the presence or absence of magnetism in this area is controlled by the control system.

[0031] Furthermore, the barrel body is a cylindrical barrel body.

[0032] A method for continuous acid hydrolysis in the above-mentioned device includes: fermentation liquid in the raw material area enters the mixing area from the feed port, mixes with sulfuric acid sprayed from the first nozzle of the first stirring blade, a control system controls the first stirring unit to stir, and discharges the mixed fermentation liquid from the discharge port into the heat exchange area for heat exchange based on the pH value displayed by the pH electrode. The fermentation liquid after heat exchange enters the acid hydrolysis area through the infusion pipe for acid hydrolysis.

[0033] The beneficial effects of the present invention are:

[0034] 1. The present invention mixes the fermentation liquid and sulfuric acid by setting a separate mixing zone. Compared with the existing large-capacity acid hydrolysis tank, the mixing zone is small in volume. By adding sulfuric acid as described above, the fermentation liquid and sulfuric acid are quickly mixed. In addition, the heat exchange zone is used for effective heat exchange before acid hydrolysis. The entire device has a compact structure and complete functions.

[0035] 2. Sulfuric acid is added at the stirring blades, and is added while stirring. After the sulfuric acid is added to the fermentation liquid, it is dispersed and mixed in time. This device can achieve accurate and timely addition of sulfuric acid to adjust the pH value in large-scale lactic acid industrial production.

[0036] 3. By setting a pH electrode on the lifting plate in the mixing zone, the pH value of the solution in the mixing zone can be detected in time, and the amount of sulfuric acid added can be accurately controlled by automatic feedback from the control system to achieve fast and efficient adjustment of the mixed solution in the mixing zone to the isoelectric point.

[0037] 4. The coordinated movement of the lifting slide rod, spiral rod and main stirring rod is used to automatically transfer the mixed liquid adjusted to the isoelectric point to the heat exchange area, which simplifies the equipment structure, avoids manual operation and saves labor costs.

[0038] 5. The two stirring units in the mixing zone and the acidolysis zone share the same main stirring rod and the same drive unit, so that the two areas can be stirred at the same time, and the acidolysis zone can also be stirred independently, saving equipment costs.

[0039] 6. In large-scale production, the solution of the present invention can realize continuous acid hydrolysis treatment, avoiding the need for a large number of acid hydrolysis tanks and corresponding auxiliary facilities such as detection, stirring, and cooling, thereby significantly reducing equipment investment and subsequent equipment operation and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of the structure of the acid hydrolysis tank in the prior art;

[0041] Figure 2 This is a schematic diagram of the mixed liquid state of the continuous acid hydrolysis device of the present invention;

[0042] Figure 3 This is a schematic diagram of the liquid discharge state of the continuous acid hydrolysis device of the present invention;

[0043] Figure 4 This is a schematic diagram of the structure of the mixing zone of the continuous acid hydrolysis device of the present invention;

[0044] Figure 5 The stirring unit of the mixing zone of the continuous acid hydrolysis device of the present invention is a three-dimensional Figure 1 ;

[0045] Figure 6 The stirring unit of the mixing zone of the continuous acid hydrolysis device of the present invention is a three-dimensional Figure 2 ;

[0046] Figure 7 This is a schematic diagram of the lifting slide structure of the stirring unit in the mixing zone of the continuous acid hydrolysis device of the present invention;

[0047] Figure 8 This is a top view of the stirring unit in the mixing zone of the continuous acid hydrolysis device of the present invention;

[0048] Figure 9 This is a top view of the relative positions of the stirring rods of the stirring unit in the mixing zone of the continuous acid hydrolysis device of the present invention;

[0049] Figure 10 This is a schematic structural diagram of the connecting and disconnecting mechanism of the continuous acid hydrolysis device of the present invention;

[0050] Figure 11 This is a schematic diagram of the installation of stirring blades on the lifting slide bar of the stirring unit in the mixing zone of the continuous acid hydrolysis device of the present invention;

[0051] Figure 12 This is a schematic diagram of the implementation of the nozzle function on the first stirring unit in the mixing zone of the continuous acid hydrolysis device of the present invention;

[0052] Figure 13 Schematic diagram of the implementation of the nozzle function on the second stirring unit in the acidolysis zone of the continuous acidolysis device of the present invention;

[0053] Figure 14 This is a schematic structural diagram of the heat exchange zone of the continuous acid hydrolysis device of the present invention;

[0054] Figure 15 This is a schematic structural diagram of the liquid transfer zone in the continuous acid hydrolysis device of the present invention;

[0055] Figure 16 Schematic diagram of the relative positions of the second control valve and the thread groove of the screw rod in the mixing zone of the continuous acid hydrolysis device of the present invention.

[0056] In the figure, 1, acid supply pipeline; 2, raw material pipeline; 3, acid hydrolysis tank; 4, stirring unit; 5, heat exchange unit; 6, liquid outlet; 11, barrel; 12, raw material area; 13, mixing area; 14, heat exchange area; 15, partition; 16, acid hydrolysis area; 17, liquid supply pipe; 18, pH electrode 1; 121, feeding port; 122, feeding port; 141, heat exchange tube inlet; 142, heat exchange tube outlet; 161, overflow port; 162, pH electrode 2; 21, liquid discharge port; 22, first stirring unit; 23, second stirring unit; 31, first drive; 32, second drive; 33, main stirring rod; 34, screw rod; 35, lifting slide rod; 36, First stirring bar; 37, first stirring blade; 38, lifting plate; 51, external thread; 61, internal thread; 81, first connecting mechanism; 811, arc plate; 812, connecting rod; 813, fixing block; 814, stopper; 815, circular groove; 816, stopper; 817, spring; 101, liquid supply hose; 102, liquid transfer area; 103, infusion tube; 1031, first control valve; 1032, second control valve; 104, first nozzle; 105 second stirring bar; 106 second stirring blade; 107, third nozzle; 111, second nozzle; 112, fourth nozzle; 143, heat exchange tube. DETAILED DESCRIPTION

[0057] In order to fully understand the process of automatic mixing of sulfuric acid and fermentation liquid for acid hydrolysis in the scheme of the present invention, the following embodiments are specifically and detailedly described in conjunction with the accompanying drawings.

[0058] See also Figure 2 、 3 The acidolysis device is a cylindrical barrel 11 as a whole, which is divided into two parts, the upper and lower parts, which are separated by a partition 15. The partition 15 has a heat insulation effect to prevent the heat generated when the upper liquid is mixed from being transferred to the lower area - the acidolysis area 16.

[0059] The upper portion of the acid hydrolysis device barrel 11 is equipped with three zones: a raw material zone 12, a mixing zone 13, and a heat exchange zone 14. The center of the entire upper region is the mixing zone 13, while the remaining areas of the mixing zone 13 are the raw material zone 12 and the heat exchange zone 14. The mixing zone 13 is also cylindrical in structure. The raw material zone 12 is located above the heat exchange zone 14, which is located below the raw material zone 12. The partition between the raw material zone 12 and the heat exchange zone 14 is located in the middle of the side wall of the mixing zone 13.

[0060] A feeding port 121 is provided at the top of the raw material area 12 for feeding liquid into the raw material area 12. A feed port 122 is provided at the lower end of the raw material area 12, near the mixing area 13, for supplying liquid from the raw material area 12 to the mixing area 13. An electronic valve is provided on the side of the feed port 122 facing the raw material area 12. This valve is controlled by the control system. When liquid needs to be supplied from the raw material area 12 to the mixing area 13, the valve opens. When liquid is not needed to be supplied to the mixing area 13, the valve closes to prevent liquid in the mixing area 13 from flowing back into the raw material area 12.

[0061] A drain port 21 is provided in the middle of the side wall of the mixing zone 13, below the partition between the raw material zone 12 and the heat exchange zone 14, for draining the mixed liquid in the mixing zone 13 into the heat exchange zone 14. A baffle is provided on the side of the drain port 21 facing the heat exchange zone 14, and the baffle can only be opened toward the heat exchange zone. When liquid needs to be drained from the mixing zone 13 to the heat exchange zone 14, the baffle is opened. When liquid does not need to be supplied to the heat exchange zone 14, the baffle is closed. This prevents liquid in the heat exchange zone 14 from flowing back into the mixing zone 13 and also prevents liquid in the mixing zone 13 from flowing into the heat exchange zone 14 during the mixing process.

[0062] Heat exchange zone 14 is provided with heat exchange tubes 143, and heat exchange tube inlet 141 and heat exchange tube outlet 142 are arranged on the side wall of heat exchange zone 14. The liquid discharged from mixing zone 13 into heat exchange zone 14 is at a high temperature, and is cooled by low temperature water flowing through heat exchange tubes 143.

[0063] A liquid supply pipe 17 is provided on the lower sidewall of the heat exchange zone 14. This liquid supply pipe 17 communicates with the lower sidewall of the acidolysis zone 16 in the lower portion of the acidolysis apparatus and is used to supply liquid within the heat exchange zone 14 to the acidolysis zone 16. An electronic valve is provided at the end of the liquid supply pipe 17 near the heat exchange zone 16 to control the liquid supply to the acidolysis zone 16. A check valve is also provided at the end of the liquid supply pipe 17 near the acidolysis zone 16 to prevent liquid from the acidolysis zone 16 from flowing back into the liquid supply pipe 17.

[0064] See also Figure 2 、 3 4. The lower part of the entire acidolysis device is the acidolysis zone 16. The central axis of the acidolysis zone 16 is on the same straight line as the central axis of the mixing zone 13 in the upper middle area of the acidolysis device. Stirring units are set in the mixing zone 13 and the acidolysis zone 16. The stirring unit located in the mixing zone 13 and the stirring unit located in the acidolysis zone 16 share the same main stirring rod 33, and the driving unit of the main stirring rod 33 - the first drive 31 is set at the top of the acidolysis device. The first stirring unit 22 is in the mixing zone 13, and the second stirring unit 23 is in the acidolysis zone. The main stirring rod 33 shared by the first stirring unit 22 and the second stirring unit 23 passes through the center of the partition 15 in the middle of the acidolysis device.

[0065] See also Figure 5 A spiral rod 34 is provided on the periphery of the main stirring rod 33 of the first stirring unit. The spiral rod 34 is a hollow cylindrical shape, and the main stirring rod 33 passes through the middle hollow part of the spiral rod 34. The length of the spiral rod 34 extends from the bottom surface of the mixing zone 13 (without passing through the partition 15 in the middle of the acidolysis device) to the top of the mixing zone 13, and passes through the top of the mixing zone 13. A second drive 32 is provided above the top of the mixing zone 13 for independently driving the above-mentioned spiral rod 34 to rotate. The first drive 31 and the second drive 32 are both motors. A waterproof sealed bearing is used to seal the main stirring rod 33 and the top of the mixing zone.

[0066] See also Figure 5 、 9 A first connecting mechanism 81 is provided between the two ends of the screw rod 34 and the main stirring rod 33, for controlling the connection and disconnection of the screw rod 34 and the main stirring rod 33. When the screw rod 34 and the main stirring rod 33 need to rotate together, the first connecting mechanism 81 is controlled to connect and fix the screw rod 34 and the main stirring rod 33. At this time, the screw rod 34 and the main stirring rod 33 rotate synchronously as a whole under the action of the first drive 31. When the screw rod 34 and the main stirring rod 33 do not need to rotate together, the first connecting mechanism 81 is controlled to disconnect the connection between the screw rod 34 and the main stirring rod 33. At this time, the screw rod 34 is separated from the main stirring rod 33 and the screw rod 34 is in a free state. When the main stirring rod 33 rotates under the drive of the first drive 31, the screw rod 34 will not rotate synchronously because it is not connected to the main stirring rod 33.

[0067] See also Figure 4 、 11 A lifting slide 35 is arranged around the screw rod 34 at the lower end of the first stirring unit 22 located in the mixing zone. The lifting slide 35 is a hollow cylinder, and the screw rod 34 passes through the hollow area in the middle of the lifting slide 35.

[0068] The maximum length of the lifting slide 35 is half the height of the mixing zone 13, that is, it extends from the bottom of the mixing zone 13 (not passing through the partition 15 in the middle of the acid hydrolysis device) to the first stirring cross bar 36 at the top of the first stirring unit 22. Figure 12 Or 13, the first stirring bar 36 of the first stirring unit 22 is fixed in the middle on the lifting slide bar 35, and the first stirring blades 37 are fixed at both ends of the first stirring bar 36. The first stirring bar 36 can be set up two at intervals, such as Figure 12 As shown, three can also be set at intervals up and down, such as Figure 13 shown.

[0069] A lifting plate 38 is provided at the bottom of the mixing zone 13. The diameter of the lifting plate 38 is consistent with the inner diameter of the mixing zone 13, and the edge of the lifting plate 38 is in close contact with the inner wall of the mixing zone 13. The contact part is made of a material with a low friction coefficient and a good sealing effect.

[0070] The lifting plate 38 is connected to the lifting slide bar 35 and can rise or fall synchronously with the lifting slide bar 35.

[0071] A pH electrode 18 is provided on the upper surface of the lifting plate 38 near the inner wall of the mixing zone 13 to detect the pH value of the mixture of sulfuric acid and fermentation liquid in the mixing zone.

[0072] The lifting slide 35, the spiral rod 34 and the main stirring rod 33 all pass through the center of the lifting plate 38. A waterproof sealed bearing is used to connect and seal the lifting plate 38, which can prevent the liquid in the mixing zone 13 from seeping into the bottom of the partition 15 during rotation.

[0073] The specific structure of the first connecting mechanism 81 is described in detail below:

[0074] like Figure 8 、 9 As shown in Figures 10 and 10, the screw rod 34 is a hollow cylindrical structure. The first connecting mechanism 81 includes a fixing block 813 provided on the inner wall of the screw rod 34. The fixing block 813 is fixed to the inner wall of the screw rod 34. A connecting rod 812 is provided at the front end of the fixing block 813. The front end of the connecting rod 812 is provided with an arc-shaped plate 811, and the other end is provided with a blocking block 816. The blocking block 816 is connected to one end of a spring 817 on the side away from the arc-shaped plate 811. The other end of the spring 817 is fixed to the fixing block 813, or directly fixed to the inner wall of the screw rod 34.

[0075] A stopper 814 is provided inside the fixing block 813 at one end close to the arc-shaped plate 811 , and a circular groove 815 is formed between the stoppers 814 , the size of which matches that of the stopper 816 .

[0076] The area of the main stirring rod 33 corresponding to the arc plate 811 is made of electromagnetic materials different from other areas, and the magnetism of this area is realized by controlling the power on and off through the control system.

[0077] When the screw rod 34 needs to rotate synchronously with the main stirring rod 33, the area on the main stirring rod 33 corresponding to the curved plate 811 is energized to generate magnetism, attracting the curved plate 811 and fixing it to the main stirring rod 33. During the attraction of the curved plate 811, the curved plate 811 drives the connecting rod 812 toward the main stirring rod 33. At this time, the blocking block 813 at the other end of the connecting rod 812 also moves toward the main stirring rod 33 and moves into the circular groove 815. The purpose of the circular groove 815 is to ensure that the screw rod 34 is more stable when rotating with the main stirring rod 33.

[0078] When the screw rod 34 no longer needs to rotate synchronously with the main stirring rod 33, the area on the main stirring rod 33 corresponding to the curved plate 811 is de-energized and de-magnetized, causing the curved plate 811 to lose its magnetic attraction and separate from the main stirring rod 33. Under the action of the spring 817, the curved plate 811 and the main stirring rod 33 can be quickly separated, maintaining a certain distance to prevent interference between the curved plate 811 and the main stirring rod 33.

[0079] The distance between the arc plate 811 and the main stirring rod 33 should not be too large, and should be controlled between 2 and 5 cm to avoid the main stirring rod 33 being unable to adsorb the arc plate 811 when the area corresponding to the arc plate 811 generates magnetism.

[0080] At the same time, the spring 817 only plays an auxiliary role, and its pulling force on the connecting rod 812 is smaller than the magnetic adsorption force of the main stirring rod 33 on the arc plate 811.

[0081] A connecting mechanism is also provided between the ends of the lifting slide 35 and the threaded rod 34. The configuration and implementation of this second connecting mechanism (not shown) is similar to the configuration and implementation of the first connecting mechanism 81 between the threaded rod 34 and the main stirring rod 33. The second connecting mechanism includes a second fixed block provided on the inner wall of the lifting slide 35, a second connecting rod provided at the front end of the second fixed block, a second curved plate provided at the front end of the second connecting rod, and a second blocking block provided at the other end of the second connecting rod. The second blocking block is connected to one end of a second spring on the side away from the second curved plate, and the other end of the second spring is fixed to the second fixed block or the inner wall of the lifting slide 35. The area of the threaded rod 34 near the second curved plate is made of electromagnetic material, and the presence or absence of magnetism in this area is controlled by a control system. The working process of the second connecting mechanism differs from that of the first connecting mechanism in that, after the second connecting mechanism is controlled so that the lifting slide 35 and the spiral rod 34 are separated from the magnetic attraction, the internal thread 61 provided on the inner side of the lifting slide 35 is still engaged with the external thread 51 on the outer wall of the spiral rod 34, so that the lifting slide 35 can rise and fall along the spiral rod 34. In this case, the second connecting mechanism actually plays a connecting role.

[0082] The following describes how the three functions of the first stirring unit 22 in the mixing zone are realized:

[0083] Function 1: While the acid hydrolysis zone 16 is stirring, the mixing zone 13 is not stirring.

[0084] When the acidolysis zone 16 is stirring, but the mixing zone 13 does not require stirring, the first disconnect mechanisms 81 (specific implementations are described below) at both ends of the screw rod 34 are activated, controlling the screw rod 34 to separate from the main stirring rod 33. At this point, the bolt rod 34 is independent of the main stirring rod 33, and the first drive 31 drives the main stirring rod 33 to rotate, stirring the solution in the acidolysis zone 16. At this point, because the first stirring unit in the mixing zone 13 is separated from the main stirring rod 33 and is not controlled by the first drive 31, and the second drive 32 is not activated, the screw rod 34 remains stationary, and the first stirring unit does not stir.

[0085] Function 2: The mixing zone 13 and the acid decomposition zone 16 are stirred synchronously.

[0086] The control system controls the first connecting mechanism 81 at both ends of the screw rod 34 to operate, and the screw rod 34 and the main stirring rod 33 are fixed to each other. When the main stirring rod 33 rotates, the screw rod 34 is driven to rotate. At this time, the second drive 32 is not started.

[0087] At the same time, the second connecting mechanism provided at both ends of the lifting slide 35 is actuated, the lifting slide 35 is fixed to the screw rod 34, and the lifting slide 35 rotates synchronously with the screw rod 34. The rotation of the lifting slide 35 drives the rotation of the first stirring cross bar 36 and the first stirring blade 37, so that the first stirring unit and the second stirring unit can stir synchronously.

[0088] Function three: The method of discharging the liquid after the mixing in the mixing zone 13 is completed.

[0089] When the sulfuric acid and fermentation liquid in the mixing zone 13 reach the isoelectric point, the liquid mixing is completed, and the mixed liquid needs to be discharged into the heat exchange zone 14 through the drain port 21 .

[0090] At this point, the control system controls the first disconnecting mechanism 81 connecting the two ends of the screw rod 34 to the main stirring rod 33 to separate, and the screw rod 34 no longer rotates synchronously with the main stirring rod 33. The first stirring unit in the mixing zone 13 stops stirring, while the second stirring unit in the acid hydrolysis zone 16 continues stirring and is not affected.

[0091] Subsequently, the second connecting mechanisms located at both ends of the lifting slide rod 35 are separated from the screw rod 34 under the control of the control system.

[0092] The second drive 32 is started to rotate the screw rod 34. Since the screw rod 34 is separated from the main stirring rod 33, the rotation of the two will not affect each other.

[0093] See also Figure 5 、 6 The inner sides of the two ends of the lifting slide 35 that contact the spiral rod 34 are provided with threads that match the spiral structure of the spiral rod 34. When the spiral rod 34 rotates, the spiral rod 34 drives the lifting slide 35 to rise or fall along the direction of the spiral rod 34.

[0094] When liquid needs to be drained, the screw 34 rotates forward, driving the lifting slide 35 to rise along the screw 34. The rise of the lifting slide 35 further drives the lifting plate 38 to rise. Because the lifting plate 38 is in close contact and sealed with the inner wall of the mixing zone 13, the lifting plate 38 drives the liquid in the mixing zone 13 to rise synchronously with it.

[0095] As the lifting plate 38 rises, the liquid level in the mixing zone 13 gradually rises. When the liquid level reaches the drain port 21 on the side wall of the mixing zone 13, the liquid in the mixing zone 13 is discharged from the drain port 21 into the heat exchange zone 14. When the height of the lifting plate 38 rises to the height of the drain port 21, the liquid in the mixing zone 13 is completely discharged into the heat exchange zone 14.

[0096] The mixed liquid in the mixing zone 13 is discharged from the mixing zone 13.

[0097] At this time, the second drive 32 controls the screw rod 34 to rotate in the opposite direction, and the lifting slide rod 35 drives the first stirring cross bar 36, the first stirring blade 37 and the lifting plate 38 to descend along the screw rod 34 to the bottom of the mixing zone 13 and restore the initial position.

[0098] While the sulfuric acid and fermentation liquid are being mixed in the mixing zone 13 and the lifting plate 38 is rising to drain the liquid, the raw material zone 12 is continuously fed from the feeding port 121. Before the lifting plate 38 falls back to the bottom of the mixing zone, the feeding of the raw material zone 12 is completed.

[0099] When the mixing zone 13 returns to its initial state, the feed port 122 of the raw material zone 12 is opened, and the liquid in the raw material zone 12 is quickly added to the mixing zone 13 for the next round of mixing.

[0100] The above-mentioned method of feeding the raw material zone is mainly to achieve rapid replenishment when the mixing zone 13 needs liquid feed, thereby saving the waiting time of the mixing zone 13.

[0101] The following describes the method of supplying sulfuric acid:

[0102] See also Figure 12 、 13The liquid mixed in the mixing zone 13 is fed with fermentation liquid from the raw material zone 12 and sulfuric acid from the liquid supply hose 101 provided inside the main stirring rod 33 .

[0103] The liquid supply hose 101 is connected from the end of the main stirring rod 33 above the first drive 31, and extends along the central area of the main stirring rod 33 to the connection with the first stirring cross bar 36. A liquid transfer area 102 is provided at the connection. The liquid transfer area 102 is connected to the first stirring blade 37 along the infusion pipe 103 inside the first stirring cross bar 36. A first nozzle 104 is provided on the first stirring blade 37. Sulfuric acid flows from the liquid supply hose 101 to the liquid transfer area 102, and then reaches the first stirring blade 37 through the infusion pipe 103, and is sprayed out from the first nozzle 104 on the first stirring blade 37 to mix with the fermentation liquid in the mixing area 13.

[0104] See also Figure 12 At the junction of the infusion tube 103 and the spiral rod 34, a first control valve 1031 and a second control valve 1032 are respectively arranged on the inner and outer sides of the spiral rod 34 on the infusion tube 103. The contact surfaces of the two control valves are located on the outer surface of the spiral rod 34, and the magnetism of the contact surfaces of the two control valves is controlled by controlling the on and off of the power to achieve magnetic adsorption or separation.

[0105] When it is necessary to stir and replenish the acid solution, the interface end face of the first control valve 1031 is energized to generate magnetism and magnetically adsorb to the end face of the second control valve 1032. Then the control system opens the first control valve 1031 and the second control valve 1032 in sequence to achieve the connection between the first control valve 1031 and the second control valve 1032, and replenishes the acid solution through the infusion tube 103 while stirring.

[0106] When the lifting slide 35 needs to rise, the control system controls the closing of the first control valve 1031 and the second control valve 1032. The contact surface of the first control valve 1031 then loses its power and magnetism, separating it from the first control valve 1032. At this point, the infusion tube 103 with the second control valve 1032 can rise along with the lifting slide. The first control valve 1031 remains in a normally closed state, preventing the liquid in the liquid transfer area 102 from flowing out.

[0107] To achieve effective magnetic attraction between the first control valve 1031 and the second control valve 1032, the second control valve 1032 protrudes from the lifting slide 35 close to the outer surface of the screw rod 34. To avoid interference between the second control valve 1032 and the threads of the screw rod 34 during the lifting process, the position of the second control valve 1032 is set to match the thread groove of the screw rod 34. That is, during the lifting process of the lifting slide 35, the protruding part of the second control valve 1032 on the lifting slide 35 is embedded in the thread groove of the external thread 51 of the screw rod 34, and moves relative to the screw rod 34 along the spiral groove. Figure 16As shown, the second control valve indicated by the dotted line in the figure is a schematic illustration of the rising position and does not refer to the actual number.

[0108] When the liquid in the mixing area is drained, the lifting slide rod 35 returns to the initial position. At this time, the second control valve 1032 returns to the initial position synchronously and is connected to the first control valve 1031 in the above manner.

[0109] Since the position where stirring is performed is fixed, the installation position of the first control valve 1031 is fixed.

[0110] Since the second stirring unit in the acidolysis zone has the second stirring horizontal rod 105 fixed on the main stirring vertical rod 33 and has no unit that moves up and down, there is no interference problem in the arrangement of the infusion tube 103.

[0111] See also Figure 15 The liquid transfer area 102 is located at the intersection of the main stirring rod 33 and the first stirring cross bar 36. The upper and lower end surfaces of the liquid transfer area 102 are connected to the liquid supply hose 101 through sealed bearings, and the two side surfaces facing the first stirring cross bar 36 are fixedly connected to the infusion tube 103. When stirring, the liquid transfer area 102 and the infusion tube 103 rotate together with the first stirring cross bar 36 around the central axis of the main stirring rod 33. Because the upper and lower surfaces of the liquid transfer area 102 are connected to the liquid supply hose 101 through sealed bearings, the liquid transfer area 102 will not affect the liquid supply hose 101 when it rotates. The liquid supply hose 101 is located at the center of the main stirring rod 33 and is independent of the main stirring rod 33, so the liquid supply hose 101 does not rotate during stirring. The purpose of setting up the liquid transfer area 102 is to ensure that the liquid transfer area 102 does not affect the liquid supply hose 101 when rotating, and the liquid supplied from the liquid supply hose 101 can be transferred to the liquid infusion tubes 103 on both sides. The above-mentioned sealed bearing can also prevent the liquid in the liquid transfer area 102 from leaking out.

[0112] The purpose of placing the first sulfuric acid nozzle 104 on the first stirring blade 37 is because sulfuric acid generates a large amount of heat when mixing with the fermentation liquid. If the sulfuric acid is added too quickly, the heat generated by the mixing cannot be quickly dissipated, which may lead to the safety risk of localized overheating and boiling of the liquid. Placing the first nozzle 104 on the first stirring blade 37 not only distributes the sulfuric acid addition points throughout the fermentation liquid, but also, when sulfuric acid is added during stirring, the sulfuric acid added to the fermentation liquid from the first nozzle 104 is immediately mixed and dispersed with the fermentation liquid by the action of the first stirring blade 37, thus avoiding the problem of localized overheating of the liquid when the sulfuric acid is added.

[0113] A pH electrode 18, mounted on the lifting plate 38 of the mixing zone 13, monitors the pH of the fermentation broth and sulfuric acid mixture within the mixing zone at all times. The control system promptly adjusts the amount of sulfuric acid supplied to the mixing zone 13 based on changes in the detected pH. If the pH electrode 18 detects that the pH value of the mixing zone 13 has not reached the isoelectric point, the control system continues to add sulfuric acid. If the pH electrode 18 detects that the pH value has reached the isoelectric point, the control system stops adding sulfuric acid.

[0114] Since sulfuric acid is added via the first stirring blades 37, the locations where it is added are dispersed throughout the fermentation liquid, and the added sulfuric acid is immediately dispersed by the first stirring blades 37. Therefore, this method allows for rapid sulfuric acid addition, significantly reducing the mixing time between the sulfuric acid and the fermentation liquid. To enhance the effectiveness of spraying sulfuric acid, a second nozzle 111 is also provided on the first stirring bar 36 of the first stirring unit 22. This increases the number of sulfuric acid ejection points, allowing the sulfuric acid ejected from the nozzle to be immediately dispersed and evenly mixed with the fermentation liquid under the stirring of the stirring unit. Multiple first stirring bars 36 of the first stirring unit 22 may be provided.

[0115] In addition, by adopting the method of lifting the lifting plate 38 to drain the liquid, the device can automatically drain the liquid without manual operation, thereby achieving the purpose of rapid mixing and rapid drainage.

[0116] The mixed liquid discharged from mixing zone 13 to heat exchange zone 14 is cooled by heat exchange tubes 143 provided in heat exchange zone 14. A temperature sensing unit (preferably a thermocouple) is installed in heat exchange zone 14 and automatically feeds the sensing results back to the cooling water control unit. The cooling water supply rate is automatically controlled based on the measured temperature. The cooling water control unit comprises a signal access unit, an analysis unit, and an execution unit. The control unit uses a pre-programmed program to analyze the temperature signal fed back by the temperature sensing unit, which is obtained from the signal access unit. The analysis unit then determines whether the cooling water flow rate should be increased or decreased. The result of this determination is then transmitted to the execution unit, which controls the speed of the cooling water pump to increase or decrease the cooling water flow rate. Both the temperature sensing unit and the cooling water control unit are controlled by the control system to ensure that the mixed liquid temperature is maintained between 35°C and 45°C.

[0117] The cooled mixed liquid is discharged to the acid decomposition zone 16 at the lower part of the acid decomposition device through the liquid supply pipe 17 arranged below the heat exchange zone 14.

[0118] pH electrodes 162 are provided in the middle and lower portions of the sidewalls of the acid hydrolysis zone 16 to further monitor changes in the pH value of the mixed solution. When sulfuric acid needs to be added for fine-tuning, the addition of sulfuric acid is controlled by the control system.

[0119] The supply of sulfuric acid in the mixing zone 13 is similar to that in the mixing zone 13, see Figure 3 A second stirring cross bar 105 is fixed to a portion of the main stirring rod 33 disposed within the acidolysis zone 16. The middle of the second stirring cross bar 105 is fixed to the main stirring rod 33. Second stirring blades 106 are respectively fixed to the ends of the second stirring cross bar 105. Multiple second stirring cross bars 105 can be provided. Sulfuric acid is supplied from a liquid supply hose 101 disposed within the main stirring rod 33 disposed within the acidolysis zone 16 to a second liquid transfer area at the intersection of the main stirring rod 33 and the second stirring cross bar 105 in the acidolysis zone 16. Sulfuric acid is then supplied to the third nozzle 107 of the second stirring blade 106 through a second liquid infusion pipe disposed within the second stirring cross bar 105.

[0120] Because the space of the acidolysis zone 16 is relatively large, in order to facilitate the rapid addition of sulfuric acid to the mixed solution to complete fine-tuning, a fourth nozzle 112 is also provided on the second stirring horizontal bar 105 of the main stirring vertical bar 33 in the acidolysis zone 16 .

[0121] The sulfuric acid supply of the above-mentioned different stirring cross bars can be individually controlled by the control system.

[0122] In order to prevent the mixed liquid from entering the nozzle, a check valve is provided at each nozzle of the mixing zone 13 and the acidolysis zone 16 to ensure that only sulfuric acid can be supplied without backflow of the mixed liquid.

[0123] An overflow port 161 is provided at the upper side wall of the acidolysis zone 16 . When the acidolysis of the liquid in the acidolysis zone 16 is completed, the liquid level reaches the overflow port 161 , and the acidolysis-completed mixed liquid is discharged from the overflow port 161 to the downstream equipment for separation.

[0124] When all the fermentation liquid is acid-hydrolyzed and no new mixed liquid is added to the acid-hydrolysis zone 16, the mixed liquid in the acid-hydrolysis zone 16 is discharged from the acid-hydrolysis zone through the drain port provided at the bottom of the acid-hydrolysis zone 16 to the downstream equipment for separation.

[0125] At this point, the process of rapid mixing and continuous acid hydrolysis of the fermentation broth is completed.

[0126] In the above technical solution, control of the stirring unit, particularly the switching between the three functions of the first stirring unit in the mixing zone, is automatically accomplished by a control system, eliminating the need for manual switching. Liquid transfer and the addition of sulfuric acid based on pH monitoring feedback are also automated, improving acid hydrolysis efficiency. The control system utilizes either a DSC or PLC control system.

[0127] The working process of the continuous acid hydrolysis device of the present invention is as follows:

[0128] The fermentation liquid after the bacterial cells are separated is added to the raw material area 12 at the upper portion of the acid hydrolysis device 11 through the feed port 121, filling the entire raw material area 12. When the mixing area 13 is ready for the addition of fermentation liquid, the feed port 122 located below the raw material area is opened, and the fermentation liquid in the raw material area 12 is quickly supplied to the mixing area 13.

[0129] After all the fermentation liquid in the raw material area 12 is transferred to the mixing area 13 , the feed port 122 is closed, and the fermentation liquid continues to be fed into the raw material area 12 from the feed port 121 .

[0130] At the same time, the corresponding areas of the main stirring rod 33 corresponding to the curved plates 811 of the first connecting mechanism 81 at both ends of the spiral rod 34 of the first stirring unit in the mixing zone 13 are energized to generate magnetism, magnetically adsorbing the curved plates 811 to the main stirring rod 33. When the curved plates 811 are adsorbed to the main stirring rod 33, the blocking blocks 816 on the connecting mechanism 81 engage with the circular grooves 815, further stabilizing the fixation of the spiral rod 34 to the main stirring rod 33 and ensuring greater stability when the spiral rod 34 rotates synchronously with the main stirring rod 33.

[0131] While the screw rod 34 and the main stirring rod 33 are fixed by magnetic attraction, the connecting and disconnecting mechanisms at both ends of the lifting slide rod 35 are fixed by attraction with the screw rod 34 in the same manner as above. The process will not be described in detail.

[0132] After the screw rod 34 is attached to the main stirring rod 33 and the lifting slide 35 is secured to the screw rod 34, the first drive 31 is activated, driving the main stirring rod 33 to rotate. The main stirring rod 33 drives the screw rod 34, which in turn drives the lifting slide 35 to rotate synchronously. The first stirring crossbar 36 and first stirring blade 37, which are fixed to the lifting slide 35, rotate synchronously, stirring the fermentation liquid in the mixing zone 13.

[0133] After the first stirring unit in the mixing zone 13 starts stirring, sulfuric acid is transported to the liquid transfer zone 102 located at the center of the first stirring horizontal bar 36 through the liquid supply hose 101 arranged inside the main stirring vertical bar 33, and then the sulfuric acid is transported to the first nozzle 104 on the first stirring blade 37 and the second nozzle 111 on the first stirring horizontal bar 36 through the infusion tube 103 arranged in the first stirring horizontal bar 36 to be added to the fermentation liquid.

[0134] During the sulfuric acid addition process, the first stirring unit continuously stirs, and the sulfuric acid added from the first nozzle 104 of the first stirring blade 37 and the second nozzle 111 of the first stirring crossbar 36 is quickly dispersed and fully mixed with the fermentation liquid.

[0135] While the sulfuric acid is being added and stirred, the

[0136] The pH electrode monitors the pH of the solution in mixing zone 13 in real time. The automated control system automatically feeds back the amount of sulfuric acid added, continuously adjusting the pH of the mixed solution in mixing zone 13. When the mixed solution reaches the isoelectric point, sulfuric acid addition is stopped. At this point, mixing of the mixed solution in mixing zone 13 is complete.

[0137] At this point, the areas of the main stirring rod 33 corresponding to the curved plates 811 of the first disconnecting mechanism 81 at both ends of the spiral rod 34 are de-energized, eliminating magnetism and separating the curved plates 811 from the main stirring rod 33. The spring 817 at the rear end of the first disconnecting mechanism 81 pulls the curved plates 811 further away from the main stirring rod 33, increasing the distance between the spiral rod 34 and the main stirring rod 33, thereby preventing interference between the main stirring rod 33 and the spiral rod 34 during rotation.

[0138] As the screw rod 34 separates from the main stirring rod 33, the second disconnecting mechanisms at both ends of the lifting slide 35 separate from the screw rod 34 in a similar manner. The difference is that after the lifting slide 35 and the screw rod 34 are separated from each other by magnetic attraction, the internal threads 61 on the inner side of the lifting slide 35 remain engaged with the external threads 51 on the outer wall of the screw rod 34, allowing the lifting slide 35 to rise and fall along the screw rod 34.

[0139] When the spiral rod 34 is separated from the main stirring rod 33, the first stirring unit in the mixing zone stops stirring.

[0140] At this time, the second drive 32 is started, and the second drive 32 drives the screw rod 34 to rotate, and the second drive 32 and the main stirring rod 33 rotate relatively independently without affecting each other.

[0141] Although the magnetic attraction between the lifting slide 35 and the screw rod 34 is released, the internal threads 61 on the inner wall of the lifting slide 35 remain engaged with the external threads 51 on the outer wall of the screw rod 34. When the screw rod 34 rotates in the forward direction, the lifting slide 35 rises synchronously, thereby driving the lifting plate 38 fixed to the bottom of the lifting slide 35 upward. The rise of the lifting plate 38 then causes all the mixed liquid in the mixing zone 13 to rise.

[0142] When the liquid level of the mixed liquid in the mixing zone 13 reaches the drain port 21 in the middle area of the mixing zone side wall, the mixed liquid is discharged from the drain port 21 into the heat exchange zone 14. When the height of the lifting plate 38 is raised to the drain port 21, the mixed liquid in the mixing zone 13 is completely discharged into the heat exchange zone 14.

[0143] The second drive 32 rotates in the opposite direction, driving the screw rod 34 to rotate in the opposite direction, so that the lifting slide 35 descends along the screw rod 34 , and the lifting plate 38 simultaneously descends to the bottom of the mixing zone 13 .

[0144] At this point, the transfer of the mixed liquid in the mixing zone 13 is completed.

[0145] During the process of liquid mixing and mixed liquid transfer in the mixing zone 13 , the raw material zone 12 completes the replenishment of the raw material liquid.

[0146] The feed port 122 is opened, and the fermentation liquid in the raw material area 12 is quickly supplied to the mixing area 13 to perform a new round of mixing of the fermentation liquid and sulfuric acid.

[0147] The mixed liquid discharged into heat exchange zone 14 exchanges heat with cooling water in heat exchange tubes 143 within heat exchange zone 14, cooling the mixed liquid. The temperature measurement unit in the heat exchange zone automatically feeds back information to the cooling water control unit, which automatically adjusts the cooling water supply rate.

[0148] The cooled mixed liquid is discharged to the bottom of acidolysis zone 16 through a liquid supply pipe located below heat exchange zone 14. At this point, the second stirring unit in acidolysis zone 16 begins stirring, and this stirring action is not affected by the operation of the first stirring unit in the mixing zone. After the mixed liquid is filled into acidolysis zone 16, the pH value of the mixed liquid in acidolysis zone 16 is monitored in real time by a pH electrode while stirring. If the pH value deviates from the isoelectric point, the automatic feedback control system opens the valve corresponding to the nozzle on the second stirring unit and adds sulfuric acid for fine-tuning.

[0149] The overflow port with the corresponding height is selected according to the acid hydrolysis time. The mixed liquid after acid hydrolysis automatically flows out of the acid hydrolysis area from the overflow port to the downstream separation process.

[0150] The raw material zone 12 is continuously replenished with raw material liquid, the mixing zone 13 is continuously mixed and then transferred to the heat exchange zone 14, and the cooled mixed liquid is continuously replenished to the acid hydrolysis zone for acid hydrolysis, thereby achieving a continuous acid hydrolysis process for the fermentation liquid.

Claims

1. A continuous acid hydrolysis device for lactic acid production, characterized in that: It comprises a barrel (11), wherein the barrel (11) is divided into an upper part and a lower part by a partition (15); A mixing zone (13) is provided at the center of the upper portion of the barrel (11), and the other zones are a raw material zone (12) and a heat exchange zone (14). The raw material zone (12) is located above the heat exchange zone (14). A feed port (122) is provided at the lower end of the raw material zone (12) near the mixing zone (13). A drain port (21) is provided at the middle of the side wall of the mixing zone (13) and below the partition between the raw material zone (12) and the heat exchange zone (14). A first stirring unit (22) is provided in the mixing zone (13), a main stirring vertical rod (33) of the first stirring unit (22) is sleeved with a spiral rod (34) on the periphery thereof, the upper end of the spiral rod (34) passes through the barrel (11) and is fixed on the second drive (32), a lifting slide rod (35) is sleeved on the periphery of the spiral rod (34), a first stirring horizontal rod (36) of the first stirring unit (22) is fixed on the lifting slide rod (35) in the middle, and first stirring blades (37) are fixed at both ends of the first stirring horizontal rod (36); a lifting plate (38) is provided at the bottom of the mixing zone (13), the diameter of the lifting plate (38) is consistent with the inner diameter of the mixing zone (13), and the edge of the lifting plate (38) is in close contact with the inner wall of the mixing zone (13), and the lifting plate (38) is connected to the lifting slide rod (35); A first connecting mechanism (81) is provided between the two ends of the screw rod (34) and the main stirring rod (33), and the first connecting mechanism (81) is used to control the connection and disconnection of the screw rod (34) and the main stirring rod (33); a second connecting mechanism is provided between the two ends of the lifting slide rod (35) and the screw rod (34), and the second connecting mechanism is used to control the connection and disconnection of the lifting slide rod (35) and the screw rod (34); An acid decomposition zone (16) is provided at the lower portion of the barrel body (11), and a second stirring unit (23) is provided in the acid decomposition zone (16). The second stirring unit (23) shares the main stirring rod (33) of the first stirring unit (22). The lower end of the main stirring rod (33) passes through the center of the partition (15), and the upper end of the main stirring rod (33) passes through the barrel body (11) and is fixed on the first drive (31).

2. The continuous acid hydrolysis device for lactic acid production according to claim 1, characterized in that: A liquid supply hose (101) is passed through the center of the main stirring rod (33) of the first stirring unit (22); the liquid supply hose (101) is connected to the first stirring blade (37) of the first stirring unit via a liquid infusion tube (103); and a first nozzle (104) is provided on the first stirring blade (37); The liquid supply hose (101) is connected from the end of the main stirring vertical rod (33) above the first drive (31), and extends along the central area of the main stirring vertical rod (33) to the connection with the first stirring horizontal rod (36). A liquid transfer area (102) is provided at the connection. The liquid transfer area (102) is located at the intersection of the main stirring vertical rod (33) and the first stirring horizontal rod (36). The upper end surface and the lower end surface of the liquid transfer area (102) are connected to the liquid supply hose (101) through a sealing bearing. The two side surfaces facing the first stirring horizontal rod (36) are fixedly connected to the liquid infusion pipe (103) respectively. A first control valve (1031) and a second control valve (1032) are respectively provided on the inner and outer sides of the spiral rod (34) on the liquid infusion pipe (103). The contact surfaces of the two control valves are located on the outer surface of the spiral rod (34). The feed ports (122) are uniformly arranged along the outer wall of the mixing zone (13), the liquid discharge ports (21) are uniformly arranged along the outer wall of the mixing zone (13), the feed ports (122) are provided with electronic valves, and the liquid discharge ports (21) are provided with baffles; a pH electrode (18) is provided in the mixing zone (13), and the pH electrode (18), the liquid supply hose (101) and the first stirring unit (22) are all controlled by a control system; The heat exchange zone (14) is provided with a heat exchange tube (143), a heat exchange tube inlet (141) and a heat exchange tube outlet (142) of the heat exchange tube (143) are provided on the side wall of the heat exchange zone (14), and the heat exchange tube (143) is provided in multiple groups and is evenly distributed in the space of the heat exchange zone (14); A liquid supply pipe (17) is connected between the heat exchange zone (14) and the acidolysis zone (16), an electronic valve is provided at one end of the liquid supply pipe (17) close to the heat exchange zone (14), and a check valve is provided at one end of the liquid supply pipe (17) close to the acidolysis zone (16), and the electronic valve is controlled by a control system; A second nozzle (111) is provided on the first stirring crossbar (36) of the first stirring unit (22); A plurality of overflow ports (161) are provided at a position above 2 / 3 of the height of the acidolysis zone (16), each overflow port (161) is provided with an electronic valve, and a second pH electrode (162) is provided in the acidolysis zone (16) at a position close to the liquid supply pipe (17) and close to the overflow port (161); The electronic valve is controlled by a control system, and the control system is used to control the pH electrode 1 (18), the pH electrode 2 (162), the first stirring unit (22) and the liquid supply hose (101).

3. The continuous acid hydrolysis device for lactic acid production according to claim 1, characterized in that: A third nozzle (107) is provided on the second stirring blade (106) of the second stirring unit (23), and a fourth nozzle (112) is provided on the second stirring crossbar (105) of the second stirring unit (23).

4. The continuous acid hydrolysis device for lactic acid production according to claim 1, characterized in that: The lower end of the spiral rod (34) reaches the bottom surface of the mixing zone (13) but does not pass through the partition (15); The first drive (31) and the second drive (32) are both motors and are controlled by a control system.

5. The continuous acidolysis device for lactic acid production according to claim 1, characterized in that: The first connecting mechanism (81) includes a fixed block (813) arranged on the inner wall of the spiral rod (34), a connecting rod (812) is arranged at the front end of the fixed block (813), a curved plate (811) is arranged at the front end of the connecting rod (812), and a blocking block (816) is arranged at the other end of the connecting rod (812), the blocking block (816) is connected to one end of a spring (817) on a side away from the curved plate (811), and the other end of the spring (817) is fixed to the fixed block (813) or the inner wall of the spiral rod (34), and the area of the main stirring rod (33) close to the curved plate (811) is made of electromagnetic material, and the presence or absence of magnetism in this area is controlled by a control system; A stopper (814) is provided inside one end of the fixing block (813) close to the arc-shaped plate (811), and a circular groove (815) is formed between the stoppers (814). The size of the circular groove (815) matches that of the stopper (816).

6. The continuous acid hydrolysis device for lactic acid production according to claim 1, characterized in that: An external thread (51) is provided on the outer wall of the spiral rod (34), and an internal thread (61) is provided on the inner wall of the lifting slide rod (35) and is engaged with the external thread (51); A liquid transfer area (102) is provided at the connection between the main stirring vertical rod (33) and the first stirring horizontal rod (36); the upper end surface and the lower end surface of the liquid transfer area (102) are connected to the liquid supply hose (101) via a sealing bearing; and the two side surfaces of the liquid transfer area (102) facing the first stirring horizontal rod (36) are fixedly connected to the liquid infusion tube (103) respectively; A first control valve (1031) and a second control valve (1032) are respectively provided on the inner and outer sides of the spiral rod (34) on the infusion tube (103). The contact surfaces of the two control valves are located on the outer surface of the spiral rod (34). The magnetic properties of the contact surfaces are controlled by the control system. The second control valve (1032) protrudes from the lifting slide rod (35) and is embedded in the thread groove of the external thread (51) of the spiral rod (34).

7. The continuous acid hydrolysis device for lactic acid production according to claim 2, characterized in that: The lifting slide rod (35), the spiral rod (34) and the main stirring rod (33) all pass through the center of the lifting plate (38) and are connected by waterproof sealed bearings. The pH electrode 1 (18) is set on the lifting plate (38).

8. The continuous acid hydrolysis device for lactic acid production according to claim 1, characterized in that: The second connecting mechanism includes a second fixed block arranged on the inner wall of the lifting slide (35), a second connecting rod is arranged at the front end of the second fixed block, a second arc plate is arranged at the front end of the second connecting rod, and a second blocking block is arranged at the other end of the second connecting rod. The second blocking block is connected to one end of a second spring on the side away from the second arc plate, and the other end of the second spring is fixed to the second fixed block or the inner wall of the lifting slide (35). The area of the spiral rod (34) close to the second arc plate is made of electromagnetic material, and the magnetism of the area is controlled by the control system.

9. The continuous acid hydrolysis device for lactic acid production according to claim 1, characterized in that: The barrel body (11) is a cylindrical barrel body (11).

10. A method for continuous acid hydrolysis in the continuous acid hydrolysis device for lactic acid production according to any one of claims 1 to 9, characterized in that: The method includes the following steps: the fermentation liquid in the raw material zone (12) enters the mixing zone (13) from the feed port (122), is mixed with the sulfuric acid sprayed from the first nozzle (104) on the first stirring blade (37), the control system controls the first stirring unit to stir, and the mixed fermentation liquid is discharged from the discharge port (21) into the heat exchange zone (14) for heat exchange according to the pH value displayed by the pH electrode (18), and the fermentation liquid after heat exchange enters the acid hydrolysis zone (16) from the liquid infusion pipe (103) for acid hydrolysis.

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