Supercritical carbon dioxide whole grain continuous processing system

Abstract

The utility model discloses a supercritical carbon dioxide whole grain continuous processing system, and belongs to the technical field of supercritical fluid processing equipment. The defects of screen mesh blockage and particle residue existing in traditional single-tank batch operation in the prior art are overcome. The main structure of the device comprises a carbon dioxide storage tank, a main tank and branch tank systems, the carbon dioxide storage tank is communicated to the interior of the main tank through an air preheater, a bottom discharge port of the main tank is connected with N branch tank systems, the N branch tank systems are connected in parallel, and the N branch tank systems are further connected back to the carbon dioxide storage tank through a carbon dioxide recovery main pipe. The grain processing device is mainly used for grain processing.

Description

Technical Field

[0001] This utility model belongs to the field of supercritical fluid processing equipment technology, and more specifically, it relates to a supercritical carbon dioxide continuous whole grain processing system. Background Technology

[0002] Supercritical carbon dioxide (SC-CO2) technology, due to its non-toxic, non-flammable, and easily diffused properties, demonstrates unique application value in the food processing field, especially in grain processing, where it can achieve multiple functions such as defatting, sterilization, enzyme inactivation, and extraction of active ingredients. However, traditional supercritical processing systems mostly adopt intermittent operation modes, resulting in bottlenecks such as long material processing cycles, low equipment utilization, and high energy consumption. Existing continuous processing devices often suffer from poor system stability due to complex high-pressure sealing structures and insufficient solid-liquid separation efficiency, especially when processing materials with high solid content such as whole grains, which are prone to problems such as screen clogging and particle residue.

[0003] Currently, most existing technologies employ single-tank batch operation. During the processing, fluid channels are often blocked due to sieve clogging, requiring frequent shutdowns for cleaning. Material transfer relies on manual operation, resulting in low efficiency and high CO2 loss. Furthermore, traditional screw conveyor structures are prone to mechanical seal failure under high-pressure supercritical environments, leading to CO2 leakage risks. They also lack dynamic separation mechanisms for grain particles of various sizes, affecting the uniformity of processing. Utility Model Content

[0004] The technical problem to be solved by this invention is to overcome the shortcomings of the existing technology and provide a supercritical carbon dioxide continuous whole grain processing system.

[0005] To achieve the above objectives, this utility model employs the following technical solution:

[0006] A supercritical carbon dioxide continuous whole grain processing system includes a carbon dioxide storage tank, a main tank, and a series of sub-tank systems. The carbon dioxide storage tank is connected to the interior of the main tank via an air preheater. The bottom outlet of the main tank is connected to N sub-tank systems, which are connected in parallel. The N sub-tank systems are also connected back to the carbon dioxide storage tank via a carbon dioxide recovery main pipe, where N is a positive integer ≥ 2.

[0007] Preferably, the tank distribution system includes a tank and a separator. The inlet of the tank is connected to the bottom outlet of the main tank via a second switching valve, and the outlet of the tank is connected to the inlet of the separator via a pressure relief valve. A third switching valve is provided at the outlet of the separator.

[0008] Preferably, the interior of the separator is also connected to the main carbon dioxide recovery pipe via a recovery branch pipe.

[0009] Preferably, the main tank includes a tank body, inside which a fixed screen, a rotating shaft, and a rotating screen are provided. The fixed screen is arranged in a ring on the inner wall of the tank body, a spiral conveying blade is provided on the rotating shaft, and the rotating screen is installed at the bottom of the rotating shaft. Gaps are provided between the inner wall of the tank body and the fixed screen, between the fixed screen and the spiral conveying blade, and between the fixed screen and the rotating screen.

[0010] Preferably, the upper end of the rotating shaft is connected to the motor via a coupling, and the upper end of the tank is provided with a grain inlet.

[0011] Preferably, a first switching valve is provided between the air preheater and the main tank.

[0012] Compared with the prior art, the beneficial effects of this utility model are:

[0013] 1. By adopting a main tank and sub-tank system design, multiple sub-tanks are connected in parallel, ensuring the continuity and efficiency of the material handling process. This not only increases the throughput per unit time but also reduces equipment downtime, achieving true continuous production.

[0014] 2. The fixed screen is made of high-precision laser-perforated stainless steel plate. Combined with the rotation of the rotating screen, it forms an effective shearing force, which promotes the sedimentation of particles and effectively prevents the screen from clogging. It is especially suitable for processing grains containing large particles.

[0015] 3. The unique design of the spiral conveyor blades (inclination spiral design, gradual thickness and tungsten carbide wear-resistant coating) and the application of the dual rotor permanent magnet coupling not only reduce rotational resistance and reduce friction and wear, but also enhance the tangential velocity and centrifugal force of the fluid, which helps to better mix and separate materials and improve the overall processing effect.

[0016] 4. Through the carbon dioxide recovery path, the carbon dioxide used in the treatment process is reintroduced into the carbon dioxide storage tank through the main recovery pipe and branch pipes, realizing the recycling of carbon dioxide and reducing resource waste.

[0017] 5. By adjusting the rotation speed of the rotating screen and the inclination angle of the spiral blades, it can dynamically adapt to grains of different densities and particle sizes (such as buckwheat and oats), achieving uniform sedimentation and efficient separation of whole grain particles, with product consistency reaching over 95%, meeting diverse processing needs;

[0018] In summary, this utility model provides a highly efficient, environmentally friendly, and effective supercritical carbon dioxide continuous processing system for whole grains that can solve the problem of particle blockage, thereby improving the processing efficiency and quality of materials such as grains. Attached Figure Description

[0019] Figure 1This is a schematic diagram of the system of this utility model;

[0020] Figure 2 This is a schematic diagram of the internal structure of the main tank in this utility model;

[0021] Figure 3 This is a schematic diagram showing the relationship between the tank, the fixed screen, and the rotating screen in this utility model.

[0022] In the diagram: 1. Carbon dioxide storage tank; 2. Air preheater; 3. First switching valve; 4. Main tank; 5. Sub-tank system; 6. Carbon dioxide recovery main pipe; 41. Grain inlet; 42. Tank body; 43. Fixed screen; 44. Screw conveyor blades; 45. Shaft; 46. Rotating screen; 47. Motor; 51. Second switching valve; 52. Sub-tank; 53. Pressure relief valve; 54. Separator; 55. Third switching valve; 56. Recovery sub-pipe. Detailed Implementation

[0023] The present invention will be further described below through specific embodiments and in conjunction with the accompanying drawings.

[0024] Example 1:

[0025] like Figure 1 As shown, a supercritical carbon dioxide continuous whole grain processing system includes a carbon dioxide storage tank 1, a main tank 4, and a distribution tank system 5. The carbon dioxide storage tank 1 is connected to the interior of the main tank 4 through an air preheater 2. The bottom outlet of the main tank 4 is connected to N distribution tank systems 5, which are connected in parallel. The N distribution tank systems 5 are also connected back to the carbon dioxide storage tank 1 through a carbon dioxide recovery main pipe 6. A first switching valve 3 is provided between the air preheater 2 and the main tank 4, where N is a positive integer ≥ 2.

[0026] In this embodiment, N is 3, the bottom of the main tank 4 has a cone angle of 60°-75°, and the three sub-tanks 52 are connected in parallel to the bottom of the main tank 4. The total volume of the main tank 4 is 2-2.5 times that of the sub-tanks 52. The top of the main tank 4 has a pressure-resistant feed port and a supercritical carbon dioxide injection pressurization port. The material is switched in sequence (first sub-tank → second sub-tank → third sub-tank cycle) by the second switching valve 51.

[0027] Example 2:

[0028] A supercritical carbon dioxide whole grain continuous processing system differs from Embodiment 1 in that the sub-tank system 5 includes a sub-tank 52 and a separator 54. The inlet of the sub-tank 52 is connected to the bottom outlet of the main tank 4 through a second switching valve 51, and the outlet of the sub-tank 52 is connected to the inlet of the separator 54 through a pressure relief valve 53. A third switching valve 55 is provided at the outlet of the separator 54, and the interior of the separator 54 is also connected to the carbon dioxide recovery main pipe 6 through a recovery branch pipe 56.

[0029] like Figure 2-3 As shown, the main tank 4 includes a tank body 42. Inside the tank body 42, there is a fixed screen 43, a rotating shaft 45, and a rotating screen 46. The fixed screen 43 is arranged in a ring on the inner wall of the tank body 42. The rotating shaft 45 is equipped with a spiral conveying blade 44. The rotating screen 46 is installed at the bottom of the rotating shaft 45. Gaps are provided between the inner wall of the tank body 42 and the fixed screen 43, between the fixed screen 43 and the spiral conveying blade 44, and between the fixed screen 43 and the rotating screen 46. The upper end of the rotating shaft 45 is connected to a motor 47 via a coupling, and a grain inlet 41 is provided at the upper end of the tank body 42.

[0030] In this embodiment, the fixed screen 43 is made of high-precision laser-drilled stainless steel plate (hole diameter 0.1-0.5mm), which is fixed to the inner wall of the tank 42 to intercept large particles and guide the flow of fluid.

[0031] The mesh openings on the rotating screen 46 adopt a gradual change from denser to looser on the outside, such as... Figure 3 As shown, the outer layer has a pore size of 0.8-2.8 mm, which is used for preliminary filtration of impurities or large particles; the middle layer has a pore size of 0.6-1.5 mm, which achieves separation of medium-sized particles; and the inner layer has a pore size of 0.4-1 mm, which is close to the precision of laser drilling.

[0032] Based on the size of the grains, the mesh size is classified as follows:

[0033] When the material is sorghum, Job's tears, soybeans or corn, the outer layer aperture of the rotating screen 46 is 2.8mm, the middle layer aperture is 1.5mm and the inner layer aperture is 1mm.

[0034] When the material is buckwheat or barley, the outer layer aperture of the rotating screen 46 is 1.8mm, the middle layer aperture is 1.2mm, and the inner layer aperture is 0.8mm.

[0035] When the material is rice, black rice or oats, the outer layer aperture of the rotating screen 46 is 0.8mm, the middle layer aperture is 0.6mm, and the inner layer aperture is 0.4mm.

[0036] The spiral conveyor blades 44 employ an inclined spiral design, preferably 20°-30°, to enhance centrifugal force by increasing the tangential velocity of the fluid, thus propelling particles (such as buckwheat) towards the conical area at the bottom of the main tank 4. During rotation, the spiral conveyor blades 44 move relative to the fixed screen 43 on the inner wall of the tank 42. Simultaneously, the rotating screen 46 cooperates with the fixed screen 43, using shearing force to promote the sedimentation of grain particles while preventing screen clogging. The blade thickness of the spiral conveyor blades 44 is designed with a gradient (3mm at the root, 1.5mm at the tip) to reduce rotational resistance, and a tungsten carbide wear-resistant coating is added to the blade tips to reduce friction and wear.

[0037] In addition, the use of a dual-rotor permanent magnet coupling and contactless transmission avoids the leakage risk caused by mechanical seals, making it especially suitable for high-pressure supercritical CO2 environments (>7.4MPa). The rotation direction of the rotating screen 46 is controlled by an external motor 47 in both forward and reverse directions. The forward rotation speed range is 50-120rpm (guided flow mode), and the reverse rotation speed is increased to 200-300rpm (mixed mode).

[0038] The working principle of this utility model is as follows:

[0039] Grains are injected through the grain inlet 41 above the main tank 4. Simultaneously, the first switch valve 3 is opened, allowing preheated supercritical carbon dioxide fluid to flow into the lower part of the main tank 4. The carbon dioxide fluid mixes with the grains through the sieve holes on the rotating screen 46. The motor 47 is then started in reverse mixing mode. After maintaining this for 30-300 minutes, the forward centrifugal separation mode is activated. The rotating screen 46 cooperates with the fixed screen 43, and the mixture is separated through the gap between the fixed screen 43 and the rotating screen 46, and the inner wall of the tank 42. The gaps between the fixed screens 43 and the screen holes of the rotating screen 46 promote the sedimentation of grain particles. For example, the rotation speed of the rotating screen 46 is low near the center and faster towards the outside. The screen holes at the center of the rotating screen 46 are dense and become sparse towards the outside. Therefore, the oats can be rotated to the center of the rotating screen 46 and then leak down to the bottom of the main tank 4 through the screen holes at the center of the rotating screen 46. After solid-liquid separation, the processed grain material settles down to the first row of sub-tanks 52 on the left side through the rotating screen 46.

[0040] After the second switch valve 51 in the first row on the left is opened, the main tank 4 empties the grains and cereals, and continues to pressurize and feed to 7.5-35MPa and 30-50℃. The sub-tank 52 in the first row on the left enters the next process. After the pressure is released twice by the pressure relief valve 53, the finished product is separated by the separator 54. The sub-tank 52 in the middle row receives the next batch of material, and the cycle continues.

Claims

1. A supercritical carbon dioxide continuous whole grain processing system, characterized in that: The system includes a carbon dioxide storage tank (1), a main tank (4), and a distribution tank system (5). The carbon dioxide storage tank (1) is connected to the interior of the main tank (4) through an air preheater (2). The bottom outlet of the main tank (4) is connected to N distribution tank systems (5). The N distribution tank systems (5) are connected in parallel, and the N distribution tank systems (5) are also connected back to the carbon dioxide storage tank (1) through a carbon dioxide recovery main pipe (6). Here, N is a positive integer ≥2.

2. The supercritical carbon dioxide whole grain continuous processing system according to claim 1, characterized in that: The tank distribution system (5) includes a tank (52) and a separator (54). The inlet of the tank (52) is connected to the bottom outlet of the main tank (4) through a second switch valve (51). The outlet of the tank (52) is connected to the inlet of the separator (54) through a pressure relief valve (53). A third switch valve (55) is provided at the outlet of the separator (54).

3. The supercritical carbon dioxide whole grain continuous processing system according to claim 2, characterized in that: The interior of the separator (54) is also connected to the carbon dioxide recovery main pipe (6) via a recovery branch pipe (56).

4. The supercritical carbon dioxide whole grain continuous processing system according to claim 3, characterized in that: The main tank (4) includes a tank body (42). Inside the tank body (42) are a fixed screen (43), a rotating shaft (45), and a rotating screen (46). The fixed screen (43) is arranged in a ring on the inner wall of the tank body (42). The rotating shaft (45) is provided with a spiral conveying blade (44). The rotating screen (46) is installed at the bottom of the rotating shaft (45). There are gaps between the inner wall of the tank body (42) and the fixed screen (43), between the fixed screen (43) and the spiral conveying blade (44), and between the fixed screen (43) and the rotating screen (46).

5. The supercritical carbon dioxide whole grain continuous processing system according to claim 4, characterized in that: The upper end of the rotating shaft (45) is connected to the motor (47) via a coupling, and the upper end of the tank (42) is provided with a grain inlet (41).

6. The supercritical carbon dioxide whole grain continuous processing system according to any one of claims 1-5, characterized in that: A first switching valve (3) is provided between the air preheater (2) and the main tank (4).

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