Low temperature desolventizing device and low temperature desolventizing process for low temperature soybean meal

Abstract

The present application discloses a low-temperature desolventizing device and a low-temperature desolventizing process for low-temperature soybean meal, wherein the low-temperature desolventizing device comprises an A-tube, a B-tube and a solvent gas heating circulation system for the A-tube, wherein the feed port of the B-tube is connected to the discharge port of the A-tube; the solvent gas heating circulation system for the A-tube comprises a heating circulation pipeline for the A-tube, and a main cyclone dust collector, a circulating fan, a solvent gas heater and a thermal resistor arranged in sequence, wherein the thermal resistor is connected to the steam automatic control valve of the solvent gas heater through a controller, and the main cyclone dust collector discharges dust into the B-tube; the A-tube is provided with a feed and an outlet settling tube separated by a partition, wherein the inner diameter of the outlet channel is larger than the inner diameter of the feed channel, and the A-tube is also provided with a tangential air inlet composed of a rectangular air inlet channel and a square-to-circular channel connected to the A-tube heating circulation pipe. The low-temperature desolventizing device and desolventizing process provided by the present application can reduce the loss of water-soluble protein, improve the molding degree of the low-temperature meal, and have a good desolventizing effect.

Description

Technical Field

[0001] The invention relates to the technical field of soybean deep processing, in particular to a low-temperature desolventizing device and a low-temperature desolventizing process for low-temperature soybean meal. Background Art

[0002] With the continuous development and utilization of soybean deep processing technology, the application field of soybean low temperature meal is becoming wider and wider. It can be used as a raw material for various protein production, such as edible protein, textured protein, concentrated protein, isolated protein and its derivative foods. The excellent properties of soybean protein provide a dual guarantee of functionality and nutrition and health for the development of protein foods; however, the nutritional value and processing cost of various soybean protein and its derivative foods are directly related to the soybean low temperature meal as a raw material. Specifically, the key issue is to solve the desolventization of low temperature meal.

[0003] At present, when desolventizing soybean meal at low temperature, part of the solvent gas with high temperature and low density entering cylinder A always forms a short-circuit circulation at the top, resulting in low heat exchange utilization and poor desolventizing effect.

[0004] Secondly, the material is turned over and runs close to the inner drum wall with outer interlayer heating, the meal material is seriously heat-denatured, the water-soluble protein loss is large, the amount of broken materials is large, the yield of low-temperature meal is low, and the color is dark and uneven;

[0005] Finally, the separation and purification of the solvent gas and the mixed gas in cylinder B are not thorough, the low-temperature desolventizing equipment is severely worn and clogged, resulting in a short continuous use cycle of the equipment. Therefore, there are problems such as incomplete desolventizing and high processing costs. Summary of the invention

[0006] One advantage of the present invention is that it provides a low-temperature desolventizing device and a low-temperature desolventizing process for low-temperature soybean meal, wherein in cylinder A, the material and the solvent gas perform reverse heat exchange and mass exchange in a specific manner, and the solvent gas is closer to the cylinder wall of cylinder A, forming a surrounding isolation layer between the material and the cylinder wall, which can not only effectively reduce the probability of contact between the material and the cylinder wall of cylinder A, thereby eliminating the thermal denaturation of the material and keeping the low-temperature meal in good color (basically no discoloration), but also effectively alleviate the phenomenon of crushing caused by the friction between the material and the cylinder wall, greatly improve the forming rate and forming degree of the low-temperature meal, the loss of water-soluble protein is not more than 2%, and the powder degree of the material under the 30-mesh sieve is not higher than 2.5%, and at the same time, it also avoids the undesirable phenomenon of short-circuit circulation of solvent gas at the top of cylinder A, thereby improving the desolventizing effect of the material.

[0007] One advantage of the present invention is that it provides a low-temperature desolventizing device and a low-temperature desolventizing process for low-temperature soybean meal, wherein the main cyclone dust collector and the exhaust diverting cyclone dust collector can not only effectively improve the separation effect of the solvent gas in the main circulation pipeline and the exhaust circulation pipeline, but also the separated dust is directly sent into the B cylinder, which can avoid the formation of secondary dust gas in the A cylinder, thereby effectively reducing the dust content of the solvent gas extracted from the A cylinder, reducing the subsequent dust removal load, and improving the solvent gas purification effect, eliminating the system blockage phenomenon, and extending the continuous operation cycle of the equipment.

[0008] One advantage of the present invention is that it provides a low-temperature desolventizing device and a low-temperature desolventizing process for low-temperature soybean meal, wherein the dust removal effect of the mixed gas discharged from the B cylinder can be greatly improved through the coordinated cooperation of the dry collector and the B cylinder wet collector.

[0009] One advantage of the present invention is that it provides a low-temperature desolventizing device and a low-temperature desolventizing process for soybean low-temperature meal, wherein the thermal resistor is connected to the steam automatic control valve of the solvent gas heater through a controller, the electrical signal of the negative pressure automatic control valve of cylinder B is connected to the pressure transmitter of cylinder B, and the air inlet of the discharge steering cyclone dust collector is connected to the air outlet pressure transmitter of cylinder A through the electrical signal of the automatic control valve. This not only reduces the operating difficulty and improves the operating accuracy, but also ensures the product quality of the low-temperature desolventizing and the reliability of the safe operation of the system.

[0010] In order to achieve at least one of the above advantages of the present invention, in a first aspect, the present invention provides a low-temperature desolventizing device for low-temperature soybean meal, comprising:

[0011] A cylinder, wherein the A cylinder is provided with a first material inlet, a first material outlet, an air inlet and an air outlet;

[0012] B cylinder, wherein the B cylinder is provided with a second feed port, a second discharge port, a first dust inlet and a B cylinder mixed gas outlet, wherein the second feed port is connected to the first discharge port; and

[0013] A cylinder solvent gas heating circulation system, comprising an A cylinder heating circulation pipeline connecting the air inlet and the air outlet, and a main cyclone dust collector, a circulation fan, a solvent gas heater and a thermal resistor arranged in sequence from one end of the air outlet to one end of the air inlet, wherein the thermal resistor is connected to the steam automatic control valve of the solvent gas heater through a controller, and the bottom outlet of the main cyclone dust collector is connected to the first dust inlet through a closing valve;

[0014] Among them, the A cylinder is provided with a feed and air outlet sedimentation cylinder extending in the vertical direction at the upper part of the feed end, and a partition is provided in the sedimentation cylinder to separate the sedimentation cylinder into a feed channel and an air outlet channel. The inner diameter of the air outlet channel is larger than the inner diameter of the feed channel, and the openings of the feed channel and the air outlet channel respectively form the first feed port and the air outlet, wherein the A cylinder also has a discharge end relative to the feed end, and the A cylinder is provided with a tangential air inlet for connecting the A cylinder heating circulation pipeline and consisting of a rectangular air inlet channel and a square-to-circular channel at the upper part of the discharge end, so that the solvent gas in the A cylinder heating circulation pipeline can enter the A cylinder along the tangential direction, wherein the square opening of the square-to-circular channel is connected to the rectangular air inlet channel with the same diameter.

[0015] According to an embodiment of the present invention, the area ratio of the circular opening to the square opening of the square-to-circular channel is 1.5-2:1, and the length-to-width ratio of the rectangular air inlet channel is 2-2.5:1.

[0016] According to an embodiment of the present invention, a rotor and a material-sliding plate arranged along the extension direction of the rotor are arranged in the A cylinder, wherein the outer edge of the material-sliding plate is wound with a spiral blade along the extension direction of the rotor, and a material-sliding plate extending in a straight line and arranged at intervals is arranged in the gap between the spiral blades, wherein the rotation direction of the rotor is consistent with the air inlet direction of the air inlet, wherein a heating outer jacket is arranged on the side wall of the A cylinder, and the rotor structure of the B cylinder is the same as the rotor structure of the A cylinder.

[0017] According to one embodiment of the present invention, the A-tube solvent gas heating circulation system also includes a solvent gas exhaust purification device, which includes an exhaust diverting cyclone dust collector and an A-tube wet collector, wherein the A-tube heating circulation pipeline is provided with a compressed air diversion tee between the circulating fan and the solvent gas heater, the circulating fan and the solvent gas heater are connected through a straight pipe of the compressed air diversion tee, the air inlet of the exhaust diverting cyclone dust collector is connected to the oblique insert pipe of the compressed air diversion tee through an automatic control valve, wherein the automatic control valve is electrically connected to the A-tube outlet pressure transmitter at the air outlet of the A-tube, the bottom outlet of the exhaust diverting cyclone dust collector is connected to the second dust inlet of the B-tube through a closing valve, the air outlet of the exhaust diverting cyclone dust collector is connected to the mixed gas inlet of the A-tube wet collector, and the top of the A-tube wet collector is provided with a first mixed gas outlet.

[0018] According to one embodiment of the present invention, the discharge turning cyclone dust collector is provided with an eccentric square rounded shape at the air inlet, wherein the discharge turning cyclone dust collector is connected to the oblique insert pipe of the compressed air diversion tee through the eccentric square rounded circular opening, and at the same time, the horizontal bottom surface of the eccentric square rounded air inlet and the front end bottom surface of the rectangular semicircular vortex inlet of the discharge turning cyclone dust collector are maintained on the same horizontal plane.

[0019] According to one embodiment of the present invention, the soybean low-temperature meal low-temperature desolventizing device also includes a B-cylinder mixed gas extraction, purification and condensation device, and the B-cylinder mixed gas extraction, purification and condensation device includes a dry collector, a B-cylinder wet collector, a B-cylinder condenser and a liquid ring vacuum pump, wherein the gas inlet of the dry collector is connected to the mixed gas outlet of the B-cylinder, the gas outlet of the dry collector is connected to the mixed gas inlet of the B-cylinder wet collector, the B-cylinder wet collector is connected to the liquid ring vacuum pump at the mixed gas outlet through the B-cylinder condenser, and the liquid ring vacuum pump is provided with a free gas outlet, wherein a B-cylinder negative pressure automatic control valve is provided between the B-cylinder condenser and the liquid ring vacuum pump, and the B-cylinder negative pressure automatic control valve is electrically connected to the B-cylinder pressure transmitter on the B-cylinder.

[0020] According to one embodiment of the present invention, the A-tube wet collector and the B-tube wet collector have the same structure, and have a mixed gas inlet arranged at the upper part and entering along the tangential direction and a liquid outlet arranged at the lower inverted cone. The A-tube wet collector is a sleeve structure, including an outer cylinder and an inner gas outlet cylinder located in the outer cylinder and suspended, wherein the outer cylinder is evenly provided with upper tube nozzles and lower tube nozzles along a ring, the upper tube nozzles and the lower tube nozzles are staggered in the height direction, and the mixed gas inlet is between the upper tube nozzles and the lower tube nozzles in the height direction, and a central nozzle is arranged in the inner gas outlet cylinder, wherein the upper tube nozzle, the lower tube nozzle and the central nozzle are all connected to the hot water outlet of the cooking tank through a hot water circulation pump, and the top opening of the cooking tank is connected to the liquid outlets of the A-tube wet collector and the B-tube wet collector, and the cooking tank is also provided with a second mixed gas outlet at the top, a sewage outlet at the bottom, and an automatic drain outlet at the upper side.

[0021] In a second aspect, the present application also provides a low-temperature desolventizing process for low-temperature soybean meal, comprising the following steps:

[0022] S10, in a reverse heat exchange manner, wet meal and high-temperature solvent gas are synchronously input into the A cylinder at both ends of the A cylinder respectively, wherein the high-temperature solvent gas travels along the inner wall of the A cylinder at an entry wind speed of 25m / s to 32m / s to form a surrounding isolation layer, and the wet meal travels in the surrounding isolation layer in an undulating and flipping manner, and the temperature of the solvent gas is 138°C to 143°C, wherein the solvent gas after heat exchange and the solvent gas escaping from the wet meal after desolventizing form a solvent gas of 66°C to 72°C, which is discharged from the exhaust channel of the A cylinder near the feed end into the solvent gas heating circulation device, and the meal material with a temperature not higher than 85°C and a solvent content not higher than 1% is sent to the B cylinder from the discharge port of the A cylinder, wherein the negative pressure value of the B cylinder is -1300 to -1700Pa;

[0023] S20, under the continuous rotation of the rotor in the B cylinder and the negative pressure of the B cylinder, and under the low-temperature heating or heat preservation of the heating half tube of the B cylinder, the material is slowly released for 10 to 15 minutes, the solvent gas escapes, and the desolventized low-temperature meal with a temperature not higher than 76° C., a water-soluble protein loss not greater than 2%, a powder degree of the material under the 30-mesh sieve not higher than 2.5%, and a solvent content not exceeding 600 PPM is obtained, and then the obtained low-temperature meal is sent to the meal warehouse for cooling, grading and packaging in sequence;

[0024] S30, the solvent gas is centrifugally separated from the gas and dust in the solvent gas heating circulation device, and the solvent gas after dust removal is diverted, most of which is heated through the main circulation pipeline to form the high-temperature solvent gas input to the A cylinder, and the separated dust is directly sent to the B cylinder, wherein the increased amount of solvent gas escaping from the wet meal after desolventizing in the A cylinder is subjected to fine dust centrifugal separation and hot water capture purification treatment through the exhaust circulation pipeline, and then the mixed gas formed after the treatment is heat exchanged and condensed, wherein the dust separated by fine dust centrifugal separation is directly sent to the B cylinder.

[0025] According to one embodiment of the present invention, in step S30, the solvent gas is separated by the main cyclone dust collector in the solvent gas heating circulation device, and the solvent gas heating circulation device also includes a circulation fan located downstream of the main cyclone dust collector and a compressed air diversion tee located downstream of the circulation fan, the straight pipe in the compressed air diversion tee constitutes part of the main circulation pipeline, and the oblique pipe in the compressed air diversion tee forms the initial end of the exhaust circulation pipeline, wherein the solvent gas in the exhaust circulation pipeline is separated by the exhaust turning cyclone dust collector, and is purified by hot water in the A cylinder wet collector to form a mixed gas, wherein the temperature of the solvent gas entering the A cylinder is monitored in real time in the main circulation pipeline, and is controlled by the steam automatic control valve on the solvent gas heater used to control heating in the main circulation pipeline, wherein in the exhaust circulation pipeline, the diversion ratio of the oblique pipe is controlled by the automatic control valve to ensure that the negative pressure value at the air outlet of the A cylinder is -1500 to -2000Pa.

[0026] According to one embodiment of the present invention, the low-temperature desolventizing process of soybean low-temperature meal also includes step S40, using a dry collector to separate the mixed gas generated by the B cylinder, wherein the separated dust is returned to the B cylinder, and the separated mixed gas is purified by hot water through a wet collector of the B cylinder, and the clean mixed gas after purification is condensed to obtain a recyclable solvent and free gas formed after condensation, wherein the free gas is pumped to a liquid ring vacuum pump through a negative pressure automatic control valve of the B cylinder, and then sent to a free gas absorption system for treatment, and the negative pressure automatic control valve of the B cylinder is electrically connected to the B cylinder pressure transmitter on the B cylinder to maintain the negative pressure value of the B cylinder.

[0027] These and other objects, features and advantages of the present invention will be fully reflected in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of the structural connection of a low-temperature desolventizing device for low-temperature soybean meal according to a preferred embodiment of the present application is shown.

[0029] Figure 2 A schematic diagram of the side cross-sectional structure of the A cylinder in the present application is shown.

[0030] Figure 3 A schematic diagram of the internal structure of cylinder A in this application is shown.

[0031] Figure 4 A schematic diagram of the front cross-section of the A-tube wet collector in the present application is shown.

[0032] Figure 5 A schematic front cross-sectional view of a dry collector in the present application is shown.

[0033] Figure 6Shows this application Figure 5 Schematic cross-sectional view along CC direction.

[0034] Figure numerals: 10-A cylinder, 101-first feed port, 102-first discharge port, 103-air inlet, 104-air outlet, 11-sedimentation cylinder, 111-partition plate, 105-feed channel, 106-air outlet channel, 107-square to round channel, 108-rectangular air inlet channel, 12-rotor, 13-scraping plate, 14-spiral blade, 15-feeding plate, 20-B cylinder, 21-B cylinder pressure transmitter, 201-second feed port , 202-second discharge port, 203-first dust inlet, 204-B cylinder mixed gas outlet, 205-second dust inlet, 31-A cylinder heating circulation pipeline, 32-main road cyclone dust collector, 321-closing valve, 33-circulating fan, 34-solvent gas heater, 341-steam automatic control valve, 35-thermal resistor, 36-compressed gas diversion tee, 41-discharge turning cyclone dust collector, 411-closing valve, 412-eccentric square to round, 4 2-A cylinder wet collector, 421-outer cylinder, 422-inner air outlet, 423-upper tube nozzle, 424-lower tube nozzle, 425-center nozzle, 43-automatic valve, 44-A cylinder air outlet pressure transmitter, 45-cooking tank, 46-hot water circulation pump, 401-first mixed gas outlet, 402-mixed gas inlet, 403-liquid outlet, 404-second mixed gas outlet, 405-drainage outlet, 51-dry collector, 5 11-shell, 513-left-handed belt blade spiral, 514-right-handed belt blade spiral, 515-linked power mechanism, 516-horizontal deflection baffle, 517-vertical deflection baffle, 502-mixed gas inlet, 503-mixed gas outlet, 504-bottom-layer spiral conveying trough, 505-bottom-layer spiral conveying trough, 52-B cylinder wet collector, 53-B cylinder condenser, 54-liquid ring vacuum pump, 55-B cylinder negative pressure automatic control valve. DETAILED DESCRIPTION

[0035] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0036] Those skilled in the art should understand that, in the disclosure of the specification, the orientation or position relationship indicated by the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the orientation or position relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0037] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0038] refer to Figures 1 to 4 A low-temperature desolventizing device for soybean low-temperature meal according to a preferred embodiment of the present invention will be described in detail below, wherein the low-temperature desolventizing device for soybean low-temperature meal comprises an A cylinder 10, a B cylinder 20 and an A cylinder solvent gas heating circulation system, wherein the A cylinder 10 is provided with a first feed port 101, a first discharge port 102, an air inlet 103 and an air outlet 104, wherein the B cylinder 20 is provided with a second feed port 201, a second discharge port 202, a first dust inlet 203 and a B cylinder mixed gas outlet 204, wherein the second feed port 202 is connected to the first discharge port 102; wherein the A cylinder solvent gas heating circulation system comprises an A cylinder heating circulation pipeline 31 connecting the air inlet 103 and the air outlet 104, and a main cyclone dust collector 32, a circulating fan 33, a solvent gas heating circulation system 34, a circulating fan 35, a solvent gas heating circulation system 36, a circulating fan 37, a circulating fan 38, a circulating fan 39, a circulating fan 40, a circulating fan 41, a circulating fan 42, a circulating fan 43, a circulating fan 44, a circulating fan 45, a circulating fan 46, a circulating fan 47, a circulating fan 48, a circulating fan 49, a circulating fan 50, a circulating fan 51, a circulating fan 52, a circulating fan 53, a circulating fan 54, a circulating fan 55, a circulating fan 56, a circulating fan 57, a circulating fan 58, a circulating fan 59, a circulating fan 60, a circulating fan 61, a circulating fan 62, a circulating fan 63, a circulating fan 64, a circulating fan 65, a circulating fan 66, a circulating fan 67, a circulating fan 68, a circulating fan 69, a circulating fan 70, a circulating fan Heater 34 and thermal resistor 35, wherein the thermal resistor 35 is connected to the steam automatic control valve 341 of the solvent gas heater 34 through a controller (PID), thereby being able to automatically and accurately control the temperature of the solvent gas input into the A cylinder 10 through the air inlet 103 during the solvent gas circulation process, wherein the bottom outlet of the main cyclone dust collector 32 is connected to the first dust inlet 203 through a closing valve 321, thereby directly sending the separated dust into the B cylinder 20 instead of the A cylinder 10, thereby avoiding the secondary dust impact on the solvent gas circulating in the A cylinder heating circulation pipeline 31, thereby effectively reducing the dust content of the solvent gas extracted from the A cylinder 10, reducing the subsequent dust removal load, improving the solvent gas purification effect, and eliminating the blockage of the system, greatly extending the continuous operation cycle of the equipment, improving work efficiency, and saving costs;

[0039] Another point to be pointed out is that in the A-tube heating circulation pipeline 31, the circulation fan 33 is located downstream of the main cyclone dust collector 32. Since the main cyclone dust collector 32 can completely remove dust particles larger than 20 microns, it can avoid the solvent gas that has not been centrifugally separated directly entering the circulation fan 33 and wearing the fan blades, and dust sticking to the blades and affecting the normal operation of the circulation fan 33.

[0040] In addition, the A cylinder 10 is provided with a feed and air outlet settling cylinder 11 extending in the vertical direction at the upper part of the feed end. At the same time, a partition 111 is provided in the settling cylinder 11 to separate the settling cylinder 11 into a feed channel 105 and an air outlet channel 106, wherein the inner diameter of the air outlet channel 106 is larger than the inner diameter of the feed channel 105, thereby reducing the dust content of the discharged solvent gas, and at the same time, it can also promote the heat exchange between the initially entering solvent-containing meal and the solvent gas to be discharged, thereby heating the entering solvent gas. The wet meal, in addition, the openings of the feed channel 105 and the outlet channel 106 respectively form the first feed port 101 and the outlet port 104, wherein the A cylinder 10 also has a discharge end relative to the feed end, wherein the A cylinder 10 is provided with a tangential air inlet for connecting the A cylinder heating circulation pipeline 31 and composed of a rectangular air inlet channel 108 and a square-to-circular channel 107 at the upper part of the discharge end, so that the solvent gas in the A cylinder heating circulation pipeline 31 can enter the A cylinder 10 along the tangential direction. , wherein the square opening of the square-to-circular channel 107 is connected to the rectangular air inlet channel 108 with the same diameter, so that the high-temperature solvent gas entering along the tangential direction will move toward the air outlet 104 close to the inner wall of the A cylinder 10 to form a surrounding isolation layer, which can greatly separate the material and the cylinder wall of the A cylinder 10, reduce the probability of direct contact between the material and the cylinder wall, and thus eliminate the problem of thermal denaturation of the material, which is beneficial to maintaining the color of the low-temperature meal (basically no color change), and effectively alleviate the fragments formed by the friction between the material and the cylinder wall, ensure the molding degree of the low-temperature meal, and also avoid the undesirable phenomenon of solvent gas short-circuit circulation at the top of the A cylinder 10. In addition, it should be noted that the special connection relationship between the square-to-circular channel 107 and the rectangular air inlet channel 108 can effectively increase the wind speed of the solvent gas entering the A cylinder 10 tangentially, meet the requirement that the solvent gas enters the A cylinder 10 and rotates along the inner wall, and at the same time achieves the purpose of obtaining the low-temperature meal of predetermined conditions through reverse heat exchange and mass exchange between the material and the solvent gas.

[0041] Generally, the wind speed of the solvent gas entering the A cylinder 10 tangentially is 25 to 32 m / s, but after entering the A cylinder 10, the wind speed continues to decrease. After the solvent gas rotates several times under the action of inertia (for example, rotating half of the stroke of the A cylinder 10), it may become a nearly linear low-speed forward movement. When the solvent gas enters the air outlet 104 and enters the air outlet duct, the speed of the solvent gas is restored and increased due to the reduction in area. In addition, for the material in the A cylinder 10, the surrounding isolation layer forms a gas cushion, so that the material is not in close contact with the cylinder wall, or the gas-material mixture is in loose contact with the cylinder wall, but the closer the contact, the better. The closer to the cylinder wall, the less material it contains and the more steam it contains, and the opposite is true farther away from the cylinder wall. Therefore, although the surrounding isolation layer formed by the solvent gas cannot achieve 100% isolation between the material and the cylinder wall, it can significantly improve or even eliminate the problem of thermal denaturation of the material compared to conventional means, so that the low-temperature meal basically does not change color, and effectively alleviates the fragments formed by the friction between the material and the cylinder wall, can reduce the loss of water-soluble protein, and ensure the molding degree of the low-temperature meal. At the same time, when the material remains relatively unchanged in cylinder A 10, the probability of heat exchange and mass exchange between the solvent gas and the material is increased, effectively ensuring the heat exchange efficiency and desolventizing effect.

[0042] In one embodiment, the area ratio of the circular opening and the square opening of the square-to-circular channel 107 is 1.5 to 2:1, so that the wind speed of the solvent gas entering the A cylinder 10 can be as high as 25m / s to 32m / s. At the same time, the aspect ratio of the rectangular air inlet channel 108 is 2 to 2.5:1. This predetermined area ratio and aspect ratio can keep the entry wind speed of the solvent gas entering the A cylinder 10 within this range, ensuring that the solvent gas is spread along the inner wall of the A cylinder 10 and rotates, effectively improving the low-temperature desolvation effect of soybean low-temperature meal. This purely physical structural design can not only effectively reduce the overall manufacturing cost, but also does not require automatic adjustment and control through electrical components. The working performance is more reliable and is more conducive to large-scale promotion and use.

[0043] In one embodiment, a rotor 12 (driven by motor frequency modulation) and a material-splitting plate 13 arranged along the extension direction of the rotor 12 are arranged in the A cylinder 10, wherein the outer edge of the material-splitting plate 13 is wound with a spiral blade 14 along the extension direction of the rotor 12, and a material-splitting plate 15 extending in a straight line and arranged at intervals is arranged in the gap between the spiral blades 14, wherein the rotation direction of the rotor 12 is consistent with the air inlet direction of the air inlet 103, and such rotation directions are superimposed and promoted on each other, so as to increase the amplitude of the material fluctuation and the number of rotations of the solvent gas, thereby ensuring sufficient heat exchange and mass exchange between the solvent gas and the material, wherein a heating outer jacket is arranged on the side wall of the A cylinder 10, and the rotor structure of the B cylinder 20 is the same as that of the A cylinder 10 (including a rotor, a material-splitting plate, spiral blades and a material-splitting plate). The material gradually moves toward the right end of the A cylinder 10 under the dragging action of the spiral blade 14. During this period, the material will fall under the action of gravity, and the falling material will be continuously flipped upward by the material shoveling plate 13 and the material flicking plate 15, thereby forming a directional conveying mode of continuous cyclic ups and downs. At the same time, since the material shoveling plate 13 and the material flicking plate 15 are only a few centimeters (3cm-9cm) away from the cylinder wall of the A cylinder 10, the solvent gas moves closely against the inner wall of the A cylinder 10, and the material is drawn into the inner circle of the hot air by the superheated solvent gas, slowly ups and downs and flips, and conducts intense heat exchange and mass exchange with the solvent gas. At the same time, the moving direction of the material is opposite to that of the solvent gas, which is a reverse heat exchange process. During the process, the temperature of the material at the first discharge port 102 of the A cylinder 10 can reach up to 85°C, while the solvent gas is at the highest temperature at the air inlet 103. Under the action of the solvent gas at 138°C to 143°C, the desolventizing effect can be effectively improved. The rotation effect of the solvent gas gradually weakens during the movement of the solvent gas in the A cylinder 10, and its temperature continues to decrease and its mass continues to increase. Finally, the solvent gas moves in an approximately linear manner and is then discharged from the air outlet 104. The wet meal temperature and the solvent gas temperature of the material at the first feed port 101 of the A cylinder 10 are the lowest, but the negative pressure value of the A cylinder 10 here is relatively the highest, that is, -1500 to -2000Pa, thereby greatly improving the heat exchange effect.

[0044] In addition, although the A cylinder 10 is also provided with a heating outer jacket on the side wall, for example, indirect steam heating is performed through a hot steam interlayer, during the desolventizing process of the material in the A cylinder 10, under the action of the solvent gas rotating around the inner cylinder wall, the material is not in close contact with the hot cylinder wall. At the same time, when the material approaches the front end of the first feed port 101 in the A cylinder 10, the rotation effect of the solvent gas here is weak or basically disappears. At the same time, the wet meal here has a high solvent content and a low temperature, and the material basically fluctuates and flips with the rotation of the rotor 12, and moves toward the first discharge port 102. Therefore, although the probability of the material contacting the cylinder wall is high, less fragments are formed, and the probability of thermal denaturation and discoloration is much smaller. Therefore, the material can be desolventized by no less than 99% within the several minutes of desolventizing time in the A cylinder 10. At the same time, the loss of water-soluble protein is less, the degree of formation of fragments is lighter, the amount is smaller, and the phenomenon of thermal denaturation and discoloration is not obvious.

[0045] In addition, the structures of the A tube 10 and the B tube 20 can be completely the same, but they can also be different in heating structure. When they are different, the heating structure of the B tube 20 is a heating half-tube, which is only preheated during the initial production. After the B tube 20 is running normally, basically no additional heat is required to meet the normal production and operation requirements of the B tube 20.

[0046] In one embodiment, the A-tube solvent gas heating circulation system further comprises a solvent gas exhaust purification device, the solvent gas exhaust purification device comprises an exhaust turning cyclone dust collector 41 and an A-tube wet collector 42, wherein the A-tube heating circulation pipeline 31 is provided with a compressed air diversion tee 36 between the circulation fan 33 and the solvent gas heater 34, and at the same time, the circulation fan 33 and the solvent gas heater 34 are connected through a straight pipe of the compressed air diversion tee 36 to form a main circulation pipeline for transportation, and the exhaust turning cyclone dust collector 41 and the A-tube wet collector 42 are provided with a compressed air diversion tee 36 between the circulation fan 33 and the solvent gas heater 34, and at the same time, the circulation fan 33 and the solvent gas heater 34 are connected through a straight pipe of the compressed air diversion tee 36 to form a main circulation pipeline for transportation. The air inlet of the cyclone dust collector 41 is connected to the oblique pipe of the compressed air diversion tee 36 through the automatic control valve 43 to form a discharge circulation pipeline for transportation, wherein the angle between the oblique pipe and the straight pipe is 30°, and at the same time, the automatic control valve 43 is electrically connected to the A cylinder air outlet pressure transmitter 44 at the air outlet 104 of the A cylinder 10, and PID control is performed through real-time feedback of the air outlet pressure to ensure that the negative pressure value at the air outlet 104 of the A cylinder 10 is always maintained in the pressure range of -1500 to -2000Pa;

[0047] In addition, the solvent gas exhaust purification device also plays the role of diverting flow and ensuring pressure balance (the maximum diverting flow can be set to 110% to 120% of the amount of solvent escaping from the heat exchange of wet meal materials). If the amount of solvent gas escaping from the A cylinder containing solvent wet meal after desolventizing is 100%, the excess 10% to 20% of the solvent gas is controlled by the automatic control valve 43 and diverted to the solvent gas exhaust purification device via a 30° inclined pipe to maintain the negative pressure value of the air outlet of the A cylinder 10. If the absolute value of the negative pressure is too large, the opening is automatically closed by the automatic control valve 43 to reduce the amount of solvent gas discharged by diversion. Combined with the relationship between the thermal resistor 35 and the steam automatic control valve 341 of the solvent gas heater 34 through the controller (PID), it can ensure that the temperature of the heated solvent gas is always within the range of 138°C to 143°C. Within the range, not only is the temperature control operation convenient and accurate, but the system safety and reliability are also higher. In addition, the bottom outlet of the exhaust turning cyclone dust collector 41 is connected to the second dust inlet 205 of the B cylinder 20 through a closing valve 411, so that the separated dust is directly sent into the B cylinder 20, thereby avoiding the secondary dust impact on the solvent gas circulating in the A cylinder heating circulation pipeline 31, and effectively reducing the dust content of the solvent gas extracted from the A cylinder 10. In addition, the air outlet of the exhaust turning cyclone dust collector 41 is connected to the mixed gas inlet of the A cylinder wet collector 42. At the same time, a first mixed gas outlet 401 is provided on the top of the A cylinder wet collector 42, so that the gas discharged from the air outlet of the exhaust turning cyclone dust collector 41 is purified by the A cylinder wet collector 42.

[0048] Further preferably, the discharge turning cyclone dust collector 41 is provided with an eccentric square circle 412 at the air inlet, wherein the discharge turning cyclone dust collector 41 is connected to the oblique insert pipe of the compressed air diversion tee 36 through the circular mouth of the eccentric square circle 412, and at the same time, the horizontal bottom surface of the air inlet of the eccentric square circle 412 and the front end bottom surface of the rectangular semicircular vortex inlet of the discharge turning cyclone dust collector 41 are maintained on the same horizontal plane, which can not only effectively improve the centrifugal separation effect of fine dust (above 1 micron), but also the eccentric square circle 412 is not easy to accumulate dust, and the solvent gas can enter more conveniently.

[0049] Further preferably, the soybean low-temperature meal low-temperature desolventizing device also includes a B-tube mixed gas extraction, purification and condensation device, and the B-tube mixed gas extraction, purification and condensation device includes a dry collector 51, a B-tube wet collector 52, a B-tube condenser 53 and a liquid ring vacuum pump 54, wherein the gas inlet of the dry collector 51 is connected to the B-tube mixed gas outlet 204, and the gas outlet of the dry collector 51 is connected to the mixed gas inlet of the B-tube wet collector 52, wherein the B-tube wet collector 52 is connected to the liquid ring vacuum pump 54 at the mixed gas outlet through the B-tube condenser 53, and the liquid ring vacuum pump 54 is provided with a free gas outlet, wherein the B-tube condenser 53 and the liquid ring vacuum pump A B-cylinder negative pressure automatic control valve 55 is arranged between 54, and the B-cylinder negative pressure automatic control valve 55 is electrically connected to the B-cylinder pressure transmitter 21 on the B-cylinder 20 to control the speed and gas volume of the mixed gas in the B-cylinder 20 during extraction, purification and condensation, ensuring that the negative pressure value of the B-cylinder 20 is always within the range of -1300 to -17000Pa. Combined with the relationship that the thermal resistor 35 is connected to the steam automatic control valve 341 of the solvent gas heater 34 through the controller (PID), and the relationship that the air inlet of the exhaust turning cyclone dust collector 41 is connected to the A-cylinder air outlet pressure transmitter 44 through the automatic control valve 43 (PID control), the overall safety and reliability of the low-temperature desolventizing device can be further improved.

[0050] More preferably, in combination Figure 5 and Figure 6The dry collector 51 is provided with a mixed gas inlet 502 at the bottom of one end of the shell 511, and a mixed gas outlet 503 at the top of the other end. The inside of the shell 511 is provided with a bottom spiral conveying trough 504, a left-handed belt blade spiral 513, an upper spiral conveying trough 505, and a right-handed belt blade spiral 514 in sequence from bottom to top, and a linkage power mechanism 515 is arranged outside the shell 511. The belt blade spiral can adapt to the slightly sticky material transportation formed by the soybean low-temperature meal dust and moisture, and it is also convenient for the gas to pass through the gap of the belt blade; the discharge of the bottom spiral conveying trough 504 is at the mixed gas inlet 502, and the discharge of the upper spiral conveying trough 505 is staggered at the left and right ends of the discharge of the bottom spiral conveying trough 504. The dust of the upper spiral conveying trough 505 is transported to the left end through the right-handed belt blade spiral 514 The material falls into the bottom spiral conveying trough 504 at the discharge point, and is then conveyed to the right end through the right-handed belt blade spiral 514 to fall into the mixed gas inlet 502 for discharge; four vertical deflection baffles 517 with staggered upper and lower air intakes are arranged in the middle of the shell 511, all of which are welded to the shell 511, and the edgemost vertical deflection baffle 517 above the mixed gas inlet 502 is arranged uppermost, and the dust separated by gravity or inertia from the four vertical deflection baffles 517 falls into the upper spiral conveying trough 505; a horizontal deflection baffle 516 is arranged in the upper part of the shell 511, and is fixed on the shell 511 and the two upwardly arranged vertical deflection baffles 517, and the air inlet hole is arranged at the end away from the mixed gas outlet 503, and the dust on the horizontal deflection baffle 516 is less, which can be observed through a sight glass and discharged through the inspection port at one end during regular maintenance.

[0051] Further preferably, the A-tube wet collector 42 and the B-tube wet collector 52 have the same structure, and are provided with a mixed gas inlet 402 arranged at the upper part for entering tangentially and a liquid outlet 403 arranged at the lower inverted cone. At the same time, the A-tube wet collector 42 is a sleeve structure, including an outer cylinder 421 and an inner gas outlet cylinder 422 located in the outer cylinder 421 and suspended, wherein the outer cylinder 421 is evenly provided with upper tube nozzles 423 and lower tube nozzles 424 along a ring, the upper tube nozzles 423 and the lower tube nozzles 424 are staggered in the height direction, and the mixed gas inlet 402 is between the upper tube nozzles 423 and the lower tube nozzles 424 in the height direction to facilitate the mixed gas to enter. At the same time, a central nozzle 425 is arranged in the inner air outlet cylinder 422, wherein the upper tube nozzle 423, the lower tube nozzle 424 and the central nozzle 425 are all connected to the hot water outlet of the cooking tank 45 through the hot water circulation pump 46, and the top opening of the cooking tank 45 is connected to the liquid outlet 403 of the A tube wet collector 42 and the B tube wet collector 52. In addition, the cooking tank 45 is also provided with a second mixed gas outlet 404 at the top, a sewage outlet 405 at the bottom, and an automatic drainage outlet at the upper part of the side, wherein the nozzles selected for the upper tube nozzle 423, the lower tube nozzle 424 and the central nozzle 425 are all spiral nozzles with non-clogging 120° solid spray. The mixed gas that needs to be purified enters the A-tube wet collector 42 tangentially and rotates. It first passes through the upper and lower layers of spray formed by four upper tube nozzles 423 and four lower tube nozzles 424, and then passes through the annular falling scattering belt formed by the spray liquid of the upper tube nozzle 423, the spray liquid of the lower tube nozzle 424 and the spray liquid of the central nozzle 425 on the outer wall and the lower edge of the inner wall of the inner outlet tube 422, and finally enters the inner outlet tube 422, and is discharged after passing through the spray of the central nozzle 425 again, which effectively ensures the effect of enhanced purification. At the same time, the mixed gas purified by the A-tube wet collector 42 enters the first evaporator shell and condenser of the mixed oil for heat utilization and solvent recovery.

[0052] In the second aspect, based on the same working principle, the present application also provides a low-temperature desolventizing process for low-temperature soybean meal, comprising the following steps:

[0053] S10, synchronously inputting wet meal and high-temperature solvent gas into the A cylinder at both ends of the A cylinder in a reverse heat exchange manner, wherein the high-temperature solvent gas travels along the inner wall of the A cylinder at an entry wind speed of 25m / s to 32m / s to form a surrounding isolation layer, and the wet meal undulates and turns in the surrounding isolation layer, so that the wet meal can fully perform reverse heat exchange and mass exchange with the solvent gas, thereby improving the heat exchange effect and the desolventizing effect, and the temperature of the solvent gas is 138°C to 143°C, wherein the solvent gas after heat exchange and the solvent gas escaping from the wet meal after desolventizing form a solvent gas of 66°C to 72°C, which is discharged from the exhaust channel of the A cylinder near the feed end into the solvent gas heating circulation device, and the meal material not higher than 85°C and containing not more than 1% of solvent is sent to the B cylinder from the discharge port of the A cylinder, wherein the negative pressure value of the B cylinder is -1300 to -1700Pa;

[0054] S20, under the continuous rotation of the rotor in the B cylinder and the negative pressure of the B cylinder, and under the low-temperature heating or heat preservation of the heating half tube of the B cylinder, the material is slowly released for 10 to 15 minutes, the solvent gas escapes, and the desolventized low-temperature meal with a temperature not higher than 76° C., a water-soluble protein loss not greater than 2%, a powder degree of the material under the 30-mesh sieve not higher than 2.5%, and a solvent content not exceeding 600 PPM is obtained, and then the obtained low-temperature meal is sent to the meal warehouse for cooling, grading and packaging in sequence;

[0055] S30, the solvent gas is centrifugally separated from the gas and dust in the solvent gas heating circulation device, and the solvent gas after dust removal is diverted, most of which is heated through the main circulation pipeline to form the high-temperature solvent gas input into the A cylinder, and the separated dust is directly sent to the B cylinder, wherein the increased amount of solvent gas escaping from the wet meal through the A cylinder desolvation is subjected to fine dust centrifugal separation and hot water capture purification treatment through the discharge circulation pipeline, and then the mixed gas formed after the treatment is heat exchanged and condensed, wherein the dust separated by fine dust centrifugal separation is directly sent to the B cylinder, thereby avoiding the secondary dust impact on the solvent gas circulating in the A cylinder heating circulation pipeline, thereby effectively reducing the dust content of the solvent gas drawn out from the A cylinder, reducing the subsequent dust removal load, improving the solvent gas purification effect, and eliminating the blockage of the system, greatly extending the continuous operation cycle of the equipment, improving work efficiency, and saving costs.

[0056] In one embodiment, in step S30, the solvent gas is separated by the main cyclone dust collector in the solvent gas heating circulation device, wherein the solvent gas heating circulation device also includes a circulation fan located downstream of the main cyclone dust collector and a compressed air diversion tee located downstream of the circulation fan, the straight pipe in the compressed air diversion tee constitutes part of the main circulation pipeline, and the oblique insert in the compressed air diversion tee forms the initial end of the exhaust circulation pipeline, wherein the solvent gas in the exhaust circulation pipeline is separated by the exhaust turning cyclone dust collector, and a mixed gas is formed after being purified by hot water in the A cylinder wet collector, In the main circulation pipeline, the temperature of the solvent gas entering the A cylinder is monitored in real time by a thermal resistor, and is controlled by a steam automatic valve on the solvent gas heater in the main circulation pipeline for controlling heating, ensuring that the temperature of the solvent gas entering the A cylinder is always within the range of 138°C to 143°C. In the exhaust circulation pipeline, the diversion ratio of the oblique pipe is controlled by an automatic valve to ensure that the negative pressure value at the air outlet of the A cylinder is always within the range of -1500 to -2000Pa. This is not only convenient and accurate to operate, but also can greatly improve the overall safety and reliability of the low-temperature desolventizing device.

[0057] Further preferably, the low-temperature desolventizing process of soybean low-temperature meal also includes step S40, using a dry collector (gravity and inertia) to separate the mixed gas generated by the B cylinder, wherein the separated dust returns to the B cylinder, and the separated mixed gas is purified by hot water through a B cylinder wet collector, and the clean mixed gas after purification is condensed to obtain a recyclable solvent and free gas formed after condensation, wherein the free gas is pumped to a liquid ring vacuum pump through a B cylinder negative pressure automatic control valve, and then sent to a free gas paraffin absorption system for treatment, and the B cylinder negative pressure automatic control valve is electrically connected to the B cylinder pressure transmitter on the B cylinder to maintain the negative pressure value of the B cylinder to ensure that it is always in the negative pressure range of -1300 to -1700Pa.

[0058] It should be noted that the terms "first, second" in the present invention are only used for descriptive purposes and do not indicate any order. They cannot be understood as indicating or implying relative importance. These terms can be interpreted as names.

[0059] It should be understood by those skilled in the art that the embodiments of the present invention described above and shown in the accompanying drawings are only examples and do not limit the present invention. The advantages of the present invention have been fully and effectively achieved. The functional and structural principles of the present invention have been demonstrated and explained in the embodiments, and the embodiments of the present invention may be deformed or modified in any way without departing from the principles.

Claims

1. A low-temperature desolventizing device for low-temperature soybean meal, characterized in that: include: A cylinder, wherein the A cylinder is provided with a first material inlet, a first material outlet, an air inlet and an air outlet; B cylinder, wherein the B cylinder is provided with a second feed port, a second discharge port, a first dust inlet and a B cylinder mixed gas outlet, wherein the second feed port is connected to the first discharge port; as well as A cylinder solvent gas heating circulation system, comprising an A cylinder heating circulation pipeline connecting the air inlet and the air outlet, and a main cyclone dust collector, a circulation fan, a solvent gas heater and a thermal resistor arranged in sequence from one end of the air outlet to one end of the air inlet, wherein the thermal resistor is connected to the steam automatic control valve of the solvent gas heater through a controller, and the bottom outlet of the main cyclone dust collector is connected to the first dust inlet through a closing valve; Wherein, the A cylinder is provided with a feed and air outlet settling cylinder extending in the vertical direction at the upper part of the feed end, and a partition is provided in the settling cylinder to separate the settling cylinder into a feed channel and an air outlet channel, the inner diameter of the air outlet channel is larger than the inner diameter of the feed channel, and the openings of the feed channel and the air outlet channel respectively form the first feed port and the air outlet, wherein the A cylinder also has a discharge end relative to the feed end, and the A cylinder is provided with a tangential air inlet for connecting the A cylinder heating circulation pipeline at the upper part of the discharge end, which is composed of a rectangular air inlet channel and a square-to-circular channel, so that the solvent gas in the A cylinder heating circulation pipeline can enter the A cylinder along the tangential direction, wherein the square opening of the square-to-circular channel is connected to the rectangular air inlet channel with the same diameter, wherein the area ratio of the circular opening of the square-to-circular channel to the square opening is 1.5-2:1, and the length-width ratio of the rectangular air inlet channel is 2-2.5:1; The A-tube solvent gas heating circulation system also includes a solvent gas exhaust purification device, which includes a discharge turning cyclone dust collector, and the A-tube heating circulation pipeline is provided with a compressed air diversion tee between the circulation fan and the solvent gas heater, and the discharge turning cyclone dust collector is provided with an eccentric square rounding at the air inlet, wherein the discharge turning cyclone dust collector is connected to the oblique insert of the compressed air diversion tee through the eccentric square rounding circular opening, and at the same time, the horizontal bottom surface of the eccentric square rounding air inlet and the front end bottom surface of the rectangular semicircular vortex inlet of the discharge turning cyclone dust collector are maintained on the same horizontal plane; It also includes a B-cylinder mixed gas extraction, purification and condensation device, which includes a dry collector, a B-cylinder wet collector, a B-cylinder condenser and a liquid ring vacuum pump, wherein the gas inlet of the dry collector is connected to the mixed gas outlet of the B-cylinder, the gas outlet of the dry collector is connected to the mixed gas inlet of the B-cylinder wet collector, and the B-cylinder wet collector is connected to the liquid ring vacuum pump at the mixed gas outlet through the B-cylinder condenser.

2. The low-temperature desolventizing device for low-temperature soybean meal according to claim 1, characterized in that: The A cylinder is provided with a rotor and a material-sliding plate arranged along the extension direction of the rotor, wherein the outer edge of the material-sliding plate is provided with a spiral blade along the extension direction of the rotor, and a material-sliding plate extending and arranged in a straight line at intervals is provided in the gap between the spiral blades, wherein the rotation direction of the rotor is consistent with the air inlet direction of the air inlet, wherein the side wall of the A cylinder is provided with a heating outer jacket, and the rotor structure of the B cylinder is the same as the rotor structure of the A cylinder.

3. The low-temperature desolventizing device for low-temperature soybean meal according to claim 2, characterized in that: The solvent gas exhaust purification device also includes an A-tube wet collector, the circulating fan and the solvent gas heater are connected through the straight pipe of the compressed air diversion tee, the air inlet of the exhaust diversion cyclone dust collector is connected to the oblique pipe of the compressed air diversion tee through an automatic control valve, wherein the automatic control valve is electrically connected to the A-tube air outlet pressure transmitter at the air outlet of the A-tube, the bottom outlet of the exhaust diversion cyclone dust collector is connected to the second dust inlet of the B-tube through a closing valve, the air outlet of the exhaust diversion cyclone dust collector is connected to the mixed gas inlet of the A-tube wet collector, and a first mixed gas outlet is provided at the top of the A-tube wet collector.

4. The low-temperature desolventizing device for low-temperature soybean meal according to claim 3, characterized in that: The liquid ring vacuum pump is provided with a free gas outlet, wherein a B-tube negative pressure automatic control valve is provided between the B-tube condenser and the liquid ring vacuum pump, and the B-tube negative pressure automatic control valve is electrically connected to a B-tube pressure transmitter on the B-tube.

5. The low-temperature desolventizing device for low-temperature soybean meal according to claim 4, characterized in that: The dry collector is provided with a mixed gas inlet at the bottom of one end of the shell, and a mixed gas outlet at the top of the other end; the lower part of the shell is provided with a bottom spiral conveying trough, a left-handed belt-blade spiral, an upper spiral conveying trough, and a right-handed belt-blade spiral in sequence from bottom to top, and a linkage power mechanism is provided outside the shell; the discharge of the bottom spiral conveying trough is at the mixed gas inlet; the discharge of the upper spiral conveying trough is staggered at the left and right ends of the discharge of the bottom spiral conveying trough; four vertical deflection baffles with staggered upper and lower air intakes are provided in the middle part of the shell, which are all welded to the shell, and the outermost vertical deflection baffle above the mixed gas inlet is arranged close to the top; a horizontal deflection baffle is provided in the upper part of the shell, which is fixed on the shell and two upwardly arranged vertical deflection baffles, and the air inlet hole is provided at the end away from the mixed gas outlet.

6. The low-temperature desolventizing device for low-temperature soybean meal according to claim 5, characterized in that: The A-tube wet collector and the B-tube wet collector have the same structure, and are provided with a mixed gas inlet arranged at the upper part for entering tangentially and a liquid outlet arranged at the lower inverted cone. The A-tube wet collector is a sleeve structure, comprising an outer cylinder and an inner gas outlet cylinder located in the outer cylinder and suspended in the air, wherein the outer cylinder is evenly provided with an upper tube nozzle and a lower tube nozzle along a ring, the upper tube nozzle and the lower tube nozzle are staggered in the height direction, and the mixed gas inlet is between the upper tube nozzle and the lower tube nozzle in the height direction, a central nozzle is arranged in the inner gas outlet cylinder, wherein the upper tube nozzle, the lower tube nozzle and the central nozzle are all connected to the hot water outlet of the cooking tank through a hot water circulation pump, the top opening of the cooking tank is connected to the liquid outlets of the A-tube wet collector and the B-tube wet collector, the cooking tank is also provided with a second mixed gas outlet at the top, a sewage outlet at the bottom, and an automatic drain outlet at the upper side.

7. A process for low temperature desolventizing soybean meal using the low temperature desolventizing device for low temperature soybean meal according to any one of claims 1 to 6, characterized in that: The following steps are involved: S10, in a reverse heat exchange manner, wet meal and high-temperature solvent gas are synchronously input into the A cylinder at both ends of the A cylinder, wherein the high-temperature solvent gas travels along the inner wall of the A cylinder at an entry wind speed of 25m / s to 32m / s to form a surrounding isolation layer, and the wet meal travels up and down in the surrounding isolation layer, and the temperature of the solvent gas is 138°C to 143°C, wherein the solvent gas after heat exchange and the solvent gas escaping from the wet meal after desolventizing form a solvent gas of 66°C to 72°C, which is discharged from the exhaust channel of the A cylinder near the feed end into the solvent gas heating circulation device, and the meal material with a temperature not higher than 85°C and a solvent content not higher than 1% is sent to the B cylinder from the discharge port of the A cylinder, wherein the negative pressure value of the B cylinder is -1300 to -1700Pa; S20, under the continuous rotation of the rotor in the B cylinder and the negative pressure of the B cylinder, and under the low-temperature heating or heat preservation of the heating half tube of the B cylinder, the material is slowly released for 10 to 15 minutes, the solvent gas escapes, and the desolventized low-temperature meal with a temperature not higher than 76° C., a water-soluble protein loss not greater than 2%, a powder degree of the material under the 30-mesh sieve not higher than 2.5%, and a solvent content not exceeding 600 PPM is obtained, and then the obtained low-temperature meal is sent to the meal warehouse for cooling, grading and packaging in sequence; S30, the solvent gas is centrifugally separated from the gas and dust in the solvent gas heating circulation device, and the solvent gas after dust removal is diverted, most of which is heated through the main circulation pipeline to form the high-temperature solvent gas input to the A cylinder, and the separated dust is directly sent to the B cylinder, wherein the increased amount of solvent gas escaping from the wet meal after desolventizing in the A cylinder is subjected to fine dust centrifugal separation and hot water capture purification treatment through the exhaust circulation pipeline, and then the mixed gas formed after the treatment is heat exchanged and condensed, wherein the dust separated by fine dust centrifugal separation is directly sent to the B cylinder.

8. The low-temperature desolventizing process of low-temperature soybean meal according to claim 7, characterized in that: In step S30, the solvent gas is separated by the main cyclone dust collector in the solvent gas heating circulation device, and the solvent gas heating circulation device also includes a circulation fan located downstream of the main cyclone dust collector and a compressed air diversion tee located downstream of the circulation fan, the straight pipe in the compressed air diversion tee constitutes part of the main circulation pipeline, and the oblique pipe in the compressed air diversion tee forms the initial end of the exhaust circulation pipeline, wherein the solvent gas in the exhaust circulation pipeline is separated by the exhaust turning cyclone dust collector, and is purified by hot water in the A cylinder wet collector to form a mixed gas, wherein the temperature of the solvent gas entering the A cylinder is monitored in real time in the main circulation pipeline, and is controlled by the steam automatic control valve on the solvent gas heater used to control heating in the main circulation pipeline, wherein in the exhaust circulation pipeline, the diversion ratio of the oblique pipe is controlled by the automatic control valve to ensure that the negative pressure value at the air outlet of the A cylinder is -1500 to -2000Pa.

9. The low-temperature desolventizing process of low-temperature soybean meal according to claim 8, characterized in that: It also includes step S40, using a dry collector to separate the mixed gas generated by the B cylinder, wherein the separated dust returns to the B cylinder, the separated mixed gas is purified by hot water through a B cylinder wet collector, and the clean mixed gas after purification is condensed to obtain a recyclable solvent and free gas formed after condensation, wherein the free gas is pumped to a liquid ring vacuum pump through a B cylinder negative pressure automatic control valve, and then sent to a free gas absorption system for treatment, and the B cylinder negative pressure automatic control valve is connected to the B cylinder pressure transmitter on the B cylinder with an electrical signal to maintain the negative pressure value of the B cylinder.

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