Integrated dual-temperature dual-stripping deodorization tower

Abstract

The present invention discloses an integrated dual-temperature dual-stripping deodorization tower, wherein a plate tower, a low-temperature stripping tower, and a high-temperature stripping tower are stacked on a skirt. The plate tower is provided with: a partition bottom plate; a pre-degassing chamber; a central vacuum cylinder extending upward from the central hole of the partition bottom plate to the middle and upper part of the plate tower; a tower plate located in the annular space between the central vacuum cylinder and the plate tower, with multiple layers from top to bottom and each equipped with a stripping pump; a falling film heat exchanger, the shell of which is located in the central vacuum cylinder, the lower end of the shell passing through the plate tower lower head and connected to an oil buffer tank below the lower tube plate, the bottom of the oil buffer tank being provided with a deodorized oil outlet; a deodorized oil inlet pipe connected to the side wall of the plate tower with the outlet end pointing to the center of the oil distribution pan; and a plate tower oil outlet connected to the side wall of the plate tower and located above the partition bottom plate. The integrated dual-temperature dual-stripping deodorization tower has a compact structure, small footprint, high heat exchange and stripping efficiency, simple piping, and good product quality.

Description

Technical Field

[0001] The invention relates to a grease deacidification and deodorization device, in particular to an integrated double-temperature double-stripping deodorization tower, belonging to the technical field of grease deacidification and deodorization devices. Background Art

[0002] Vegetable oil deodorization involves a high-temperature, high-vacuum steam distillation process. It not only removes odorous substances such as free fatty acids, aldehydes, ketones, and unsaturated hydrocarbons, but also peroxides, decomposition products resulting from improper oil growth, transportation, and storage, mold, small-molecule aromatic hydrocarbons, and pesticide residues. The high-temperature process also destroys and removes some pigments. Therefore, oil deodorization not only removes free fatty acids and odorous components, increases smoke point, reduces color, improves flavor, and extends shelf life, but also controls the formation of harmful substances.

[0003] With increasing public concern about food safety, countries around the world are enacting regulations to tighten limits on harmful substances such as trans acids, glycidyl esters, trichloropropane esters, plasticizers, zearalenone, and deodorizing polymers in refined oils. These harmful components have been shown to be strongly correlated with deodorization temperature, deodorization time, and deodorization stripping efficiency. Deodorization is a complex process that seamlessly combines removal with thermal effects. The industry advocates for moderate refining, which aims to retain more nutrients in the oil while simultaneously reducing the levels of harmful substances such as trans acids, plasticizers, glycidyl esters, and trichloropropane esters.

[0004] Currently, the latest dual-temperature, dual-stripping deodorization process is used. This process uses packing to rapidly and efficiently remove acid, odor, and harmful components, while maintaining the necessary reaction heat and decolorization time at low temperatures using a plate tower. The deodorization unit currently includes the following functional modules: 1. Low-temperature degassing and deoxygenation module; 2. Pre-stripping deacidification module; 3. Plate tower deodorization and thermal decolorization module; 4. Post-stripping enhanced deodorization module; 5. Deodorization distillate capture and recovery module; 6. Hot and cold oil heat recovery module; and 7. Final oil heating module.

[0005] At present, the above deodorization function modules are generally realized in the industry by combining a packed tower + a plate tower, or by combining a tower with an external post-stripping packed tower, an external heat recovery heat exchanger, and an oil final heater. This situation, on the one hand, requires large equipment layout space, large equipment investment, complex pipeline connections, large vacuum gas resistance along the way, large heat loss, and the risk of leakage. The finished oil is oxidized, affecting the oil quality and increasing the vacuum pumping load. On the other hand, the efficiency of the heat recovery heat exchanger for hot and cold oils is not high, requiring additional heat exchangers or spiral coils in the tower to achieve dual-temperature and dual-stripping. The final oil heating adopts the oil-immersed coil method with direct steam stirring to enhance the heat transfer efficiency. This results in a long residence time of the oil at high temperature, mixing back, oil polymerization reaction, the formation of harmful polymers, and the difficulty in cleaning the residual oil scale. It also consumes extra steam and makes it difficult to switch between oil products in multiple batches.

[0006] The Chinese invention patent with publication number CN204311045U discloses a dry deodorization equipment for oils and fats, including a heat exchanger, a heater, a deodorization tower and a dry steam tower. The heat exchanger is provided with a low-temperature oil inlet and a high-temperature oil inlet and an inlet. The low-temperature oil outlet of the heat exchanger is connected to the shell-side inlet of the heater, the shell-side outlet of the heater is connected to the deodorization tower's deodorized oil inlet, the deodorized oil outlet of the deodorization tower is connected to the oil inlet of the dry steam tower, a deodorized oil outlet is provided at the bottom of the dry steam tower, the deodorized oil outlet of the dry steam tower is connected to the high-temperature oil inlet of the heat exchanger, and the high-temperature oil outlet of the heat exchanger is connected to a subsequent cooling section; the tube-side inlet and outlet of the heater are connected to a high-temperature heat source, a direct steam inlet is provided at the bottom of the side; and a direct steam inlet is provided on the side of the deodorization tower.

[0007] The Chinese invention patent with publication number CN202322774U discloses a grease deodorization system device, in which a falling film heat exchanger is connected to the top of a Taiji deodorization tower through a pipeline, the Taiji deodorization tower and the falling film heat exchanger are connected in parallel with a fatty acid collector through a pipeline, a high-temperature heating coil is provided at the top of the inner side of the Taiji deodorization tower, the high-temperature heating coil is connected to a high-pressure boiler provided outside the Taiji deodorization tower through a pipeline, a mammoth pump is provided inside the Taiji deodorization tower, and a packing device is provided in the middle position of the inner side of the Taiji deodorization tower.

[0008] Both of the above invention patents adopt the method of placing the heat exchanger outside the tower. In addition to the above-mentioned disadvantages of occupying space and complex piping, even if there is a slight leakage at the upper connecting flange of the heat exchanger, once air is sucked into the equipment, it will cause the finished oil to be oxidized, affecting the oil quality, and increasing the vacuum pumping load.

[0009] The Chinese utility model patent with publication number CN218642694U discloses a zero-trans fatty acid deodorization system for edible oil, in which the oil pipe to be deodorized is connected to the upper inlet of a gas analyzer, the bottom outlet of the gas analyzer is connected to the shell-side inlet of a falling-film oil-to-oil heat exchanger via a deoxygenated oil transfer pump, the shell-side outlet of the oil-to-oil heat exchanger is connected to the upper oil inlet of a combined deodorization tower, the bottom outlet of the combined deodorization tower is connected to the tube-side inlet of a vertical falling-film heater via a combined-tower oil transfer pump, the tube-side outlet of the vertical falling-film heater is connected to the upper oil inlet of a packed deodorization tower, the bottom oil outlet of the packed deodorization tower is connected to the tube-side inlet of the falling-film oil-to-oil heat exchanger via a packed-tower oil transfer pump, and the bottom outlet of the falling-film oil-to-oil heat exchanger is connected to the finished deodorized oil output pipe via a finished oil transfer pump and a cooler; the top exhaust ports of the gas analyzer, the oil-to-oil heat exchanger, and the deodorization tower are respectively connected to a fatty acid trap and a vacuum system.

[0010] The Chinese utility model patent with publication number CN216946903U discloses a dual-temperature deodorization and national standard zero trans fatty acid edible oil refining device, which includes a vegetable oil storage tank to be deodorized, a high-pressure pump connected to the bottom pipe of the vegetable oil storage tank to be deodorized, and the outlet pipe of the high-pressure pump is connected to an oil-oil heat exchanger. The top outlet of the oil-oil heat exchanger is sent to a first high-temperature steam heater through a conveying pipe. The first high-temperature steam heater heats the vegetable oil and then sends it to a deodorization tower for deodorization. The oil coming out of the deodorization tower is pumped to a second high-temperature steam heater and then sent to a deacidification tower for deacidification and deodorization. The refined oil at the outlet of the deacidification tower is pumped to the oil-oil heat exchanger to serve as a heating heat source for heat exchange.

[0011] The above two utility model patents adopt variable temperature double-packing stripping, a combination tower plus a post-stripping packing tower. In this mode, the equipment occupies a large area, the pipeline connection is complicated, the vacuum gas has large resistance along the way, the heat loss is large, there is a risk of leakage, and the overall cost is high.

[0012] Chinese invention patent publication number CN103409236B discloses a modular deacidification and deodorization tower suitable for edible oil deodorization in the oil and fat industry. This is currently the most commonly used modular tower. However, its drawbacks include structural difficulties in implementing a temperature-variable deacidification and deodorization process, difficulties in balancing trans-acid control with the efficient stripping of fatty acids and glycidyl esters, limited process adjustment capabilities for oils with high acid values ​​and unsaturated fatty acid content, and difficulty meeting product oil quality standards. Summary of the Invention

[0013] The purpose of the present invention is to overcome the problems existing in the prior art and provide an integrated dual-temperature dual-stripping deodorization tower, which scientifically integrates various deodorization functional modules into one, has a compact structure, occupies a small area, has high heat exchange and stripping efficiency, and has simple pipelines and good product quality.

[0014] In order to solve the above technical problems, the present invention provides an integrated dual-temperature dual-stripping deodorization tower, comprising a skirt supported on the ground, on which a plate tower, a low-temperature stripping tower and a high-temperature stripping tower are stacked in sequence from bottom to top, and the plate tower is provided with:

[0015] The cavity bottom plate is located at the lower part of the inner cavity of the plate tower;

[0016] The pre-degassing chamber is formed by the bottom plate of the compartment and the lower head of the plate tower, and is evenly distributed with decolorizing oil spray pipes on the top. The upper side wall is provided with a decolorizing oil inlet and a pre-degassing vacuum port. The decolorizing oil inlet is connected to the decolorizing oil spray pipe, and the lower part of the lower head of the plate tower is provided with a pre-degassing oil outlet.

[0017] A central vacuum cylinder extends upward from the central hole of the compartment bottom plate to the middle and upper part of the plate tower cylinder, and is provided with a central cylinder oil shield on the top;

[0018] The tower tray is located in the annular space between the central vacuum cylinder and the plate tower cylinder, and is provided with multiple layers from top to bottom and each is equipped with a steam stripping pump;

[0019] Falling film heat exchanger, the shell is located in the central vacuum cylinder, the inner cavity of the shell is provided with falling film tubes, the falling film tubes run through the upper tube sheet and the lower tube sheet, an oil distribution pan is provided above the upper tube sheet; the lower end of the shell passes through the lower head of the plate tower and is connected to an oil buffer tank below the lower tube sheet, and a deodorized oil outlet is provided at the bottom of the oil buffer tank;

[0020] a deodorized oil inlet pipe connected to the side wall of the plate tower barrel and with its outlet end pointing to the center of the oil distribution pan;

[0021] A plate tower oil outlet is connected to the side wall of the plate tower barrel and is located above the compartment bottom plate;

[0022] The vent holes are evenly distributed on the circumference of the central vacuum cylinder and enable the gas phase space of the tower plate to communicate with the inner cavity of the central vacuum cylinder.

[0023] As an improvement of the present invention, a heat exchanger shell-side inlet is provided at the lower part of the shell of the falling film heat exchanger, and a heat exchanger shell-side outlet is provided at the upper part of the shell of the falling film heat exchanger and extends out of the plate tower barrel; the pre-degassing oil outlet is connected to the inlet of the pre-degassing oil pump, and the outlet of the pre-degassing oil pump is connected to the shell-side inlet of the heat exchanger.

[0024] As a further improvement of the present invention, a lower oil distribution trough is radially provided at the upper end of the low-temperature stripping tower barrel, a low-temperature stripping oil inlet pipe for supplying oil to the lower oil distribution trough is provided above the lower oil distribution trough, and the shell-side outlet of the heat exchanger is connected to the inlet of the low-temperature stripping oil inlet pipe upward through a decolorization hot oil pipe; a plurality of lower oil distribution branch troughs are connected below the lower oil distribution trough, and the bottom of each lower oil distribution branch trough is provided with oil distribution holes; a pre-stripping low-temperature filler is provided below the lower oil distribution branch trough, and the bottom of the pre-stripping low-temperature filler is supported on the lower grid, and the lower grid is supported on the bottom inner wall of the low-temperature stripping tower barrel.

[0025] As a further improvement of the present invention, each tower plate is respectively provided with a partitioned inner tube coaxial with the plate tower barrel, the inner side of the partitioned inner tube is the inner ring flow channel, and the outer side of the partitioned inner tube is the outer ring flow channel; a radial partition is provided between the outer wall of the central vacuum tube and the inner wall of the plate tower barrel; the outlet of the overflow pipe of the upper tower plate turns to point to the head end of the inner ring flow channel close to the side of the radial partition, and the tail end of the partitioned inner tube close to the other side of the radial partition is provided with a notch connected to the head end of the outer ring flow channel.

[0026] As a further improvement of the present invention, the tail end of the outer ring flow channel is provided with a tower plate overflow pipe for overflowing to the head end of the inner ring flow channel of the next layer; or the head end of the inner ring flow channel is provided with a tower plate overflow pipe for overflowing to the tail end of the outer ring flow channel of the next layer; or the tail end of the outer ring flow channel is provided with a tower plate overflow pipe for overflowing to the tail end of the outer ring flow channel of the next layer, and the head end of the inner ring flow channel is provided with a tower plate overflow pipe for overflowing to the head end of the inner ring flow channel of the next layer.

[0027] As a further improvement of the present invention, a conical guide ring is provided below the lower grid to guide the oil into the inner annular flow channel on the tower tray.

[0028] As a further improvement of the present invention, each of the tower plates is tilted so as to be higher on the outside and lower on the inside, and a tower plate drain pipe is connected to the lowest point of the tower plate. The tower plate drain pipe of each layer extends to the outside of the plate tower barrel and is connected to the tower plate reflux port of the lower layer through a drain valve. The tower plate reflux port is located below the liquid level of the outer ring flow channel.

[0029] As a further improvement of the present invention, a plate tower annular air injection pipe is provided above the bottom plate of the compartment.

[0030] As a further improvement of the present invention, a reduced diameter section of the central vacuum cylinder is provided at the lower part, the upper end of the reduced diameter section of the vacuum cylinder is located below the vent hole of the bottom layer, and a liquid sealing disk is provided at the lower end of the reduced diameter section of the vacuum cylinder, and a drainage hole is provided on the liquid sealing disk.

[0031] As a further improvement of the present invention, an oil dispersing cylinder for evenly overflowing toward the oil distribution pan is provided below the inner end of the deodorized oil inlet pipe. The oil distribution pan is fixed above the upper tube plate of the falling film heat exchanger by supporting bolts. The oil distribution pan is evenly distributed with a plurality of oil distribution holes which are narrow at the top and wide at the bottom. The projections of the oil distribution holes are symmetrically distributed in the form of a right triangle around the upper tube openings of each falling film tube array; the oil distribution pan is evenly distributed with air permeable pipes passing through the oil layer.

[0032] As a further improvement of the present invention, the inner cavity of the high-temperature stripping tower is provided with an inner cylinder coaxial therewith, the inner cavity of the inner cylinder is provided with a post-high-temperature filler, the bottom of the inner cylinder is provided with a closed inner cylinder lower cone bucket, the inner cavity of the inner cylinder lower cone bucket is provided with an annular stripping steam injection pipe, the bottom of the inner cylinder lower cone bucket is connected to a post-stripping oil outlet, and an annular gas phase channel is formed between the outer wall of the inner cylinder and the inner wall of the high-temperature stripping tower;

[0033] An upper oil distribution groove is radially provided above the post-raising temperature packing, and a high-temperature steam stripping oil inlet pipe for supplying oil to the upper oil distribution groove is provided above the upper oil distribution groove; a plurality of upper oil distribution branch grooves are connected below the upper oil distribution groove, and the bottom of each upper oil distribution branch groove is provided with oil distribution holes for evenly distributing oil to the post-raising temperature packing.

[0034] As a further improvement of the present invention, the post-stripping oil outlet is connected downwardly to the inlet of the deodorized oil inlet pipe through a high-temperature deodorizing oil pipe, the plate tower oil outlet is connected to the inlet of a plate tower oil outlet pump, the outlet of the plate tower oil outlet pump is connected to the top oil inlet of the falling film heater through a plate tower oil outlet pipe, and the bottom oil outlet of the falling film heater is connected to the inlet of the high-temperature stripping oil inlet pipe.

[0035] As a further improvement of the present invention, a gas-liquid separation chamber is provided at the lower end of the falling film heater, the bottom oil outlet of the gas-liquid separation chamber is connected to the inlet of the high-temperature stripping oil inlet pipe, the upper gas phase port of the gas-liquid separation chamber is connected to the tangential air inlet of the upper side wall of the high-temperature stripping tower through a gas phase discharge pipe, and the inner port of the tangential air inlet is connected to the annular gas phase channel on the outer periphery of the inner cylinder.

[0036] As a further improvement of the present invention, two falling film heaters are symmetrically provided above both sides of the high-temperature stripping tower, and two tangential air inlets are also centrally symmetrically provided on the upper side wall of the high-temperature stripping tower.

[0037] As a further improvement of the present invention, a high-temperature capturing tower is stacked above the high-temperature stripping tower barrel, a high-temperature liquid distribution tank is provided on the upper part of the high-temperature capturing tower, a high-temperature section capturing liquid inlet pipe for supplying liquid to the high-temperature liquid distribution tank is provided above the high-temperature liquid distribution tank, a plurality of high-temperature liquid distribution branch tanks are connected to the bottom of the high-temperature liquid distribution tank, and the bottom of each high-temperature liquid distribution branch tank is provided with liquid distribution holes; a high-temperature capturing filler is provided below the high-temperature liquid distribution branch tank; a high-temperature stripping liquid blocking cover is provided on the top of the high-temperature stripping tower barrel, a high-temperature section liquid collecting ring is provided below the outer edge of the high-temperature stripping liquid blocking cover, and the bottom of the high-temperature section liquid collecting ring is connected to the high-temperature section capturing liquid outlet pipe.

[0038] As a further improvement of the present invention, a low-temperature capture tower is stacked above the high-temperature stripping tower, a low-temperature liquid distribution trough is provided on the upper part of the low-temperature capture tower, a low-temperature section capture liquid inlet pipe for supplying liquid to the low-temperature liquid distribution trough is provided above the low-temperature liquid distribution trough, a plurality of low-temperature liquid distribution branch troughs are connected to the bottom of the low-temperature liquid distribution trough, and the bottom of each low-temperature liquid distribution branch trough is provided with liquid distribution holes; a low-temperature capture filler is provided below the low-temperature liquid distribution branch trough; a high-temperature capture liquid blocking cover is provided on the top of the high-temperature capture tower, a low-temperature section liquid collecting ring is provided below the outer edge of the high-temperature capture, and the bottom of the low-temperature section liquid collecting ring is connected to the low-temperature section capture liquid outlet pipe; a defoaming device is provided above the low-temperature section capture liquid inlet pipe, and a tower body total exhaust port is provided at the top center of the low-temperature capture tower.

[0039] Compared with the prior art, the present invention achieves the following beneficial effects: 1. In the deodorizing packed tower, due to the large specific surface area of ​​the packing layer, the oil and steam are in thin film contact, which saves steam consumption and has a significant deacidification effect; at the same time, the oil stays in the packing layer for a very short time of about 3-5 minutes, and trans acid is not easily generated at high temperatures; however, the deodorization and thermal decolorization capabilities are limited; the variable temperature deodorization process ensures a certain thermal decolorization and deodorization residence time at low temperatures, while the residence time in the high-temperature packing section is required to be very short, resulting in high deacidification efficiency and effectively reducing the generation of harmful substances such as trans fatty acids, 3-chloropropanol esters, and glycidyl esters.

[0040] First, the decolorized oil is heat-exchanged and then fed into a pre-stripping low-temperature packing, fully utilizing the stripping steam from the lower plate tower. Due to the high fatty acid content in the oil at this initial stage, excellent deacidification is achieved even at low temperatures, making it particularly suitable for oils with high acid values. Furthermore, the oil from the pre-stripping low-temperature packing flows directly into the plate tower, eliminating the need for pumps. The low-temperature mode in the plate tower ensures the necessary residence time, allowing for controlled thermal decomposition, thermal decolorization, trans-acid formation, and polymer formation. Each plate tower layer is equipped with an oversized vent valve to adjust the oil's residence time according to process requirements. After the final heating, the oil from the plate tower enters the high-temperature packing, where it is stripped again through the packing layer. The process is under optimal high vacuum (the upper section is close to the vacuum exhaust port), high temperature, short time, and independent fresh stripping steam (to enhance the driving force of mass transfer). These excellent process parameters can effectively and quickly remove harmful substances such as 3-chloropropanol esters, glycidyl esters, plasticizers, and zearalenone, as well as polymers generated during the plate tower thermal decolorization process and free fatty acids produced by oil hydrolysis, thereby improving the quality of the finished oil. The short high-temperature residence time plays a vital role in inhibiting the formation of trans acids and glycidyl esters.

[0041] 2. The post-stripping section adopts a built-in double-shell interlayer air flow channel, and the gas phases of the pre-stripping section and the plate tower section and the post-stripping section are independently and parallelly evacuated, achieving the following effects: a. It has a heat preservation effect on the post-stripping section; b. It reduces the resistance of the gas phase along the way and ensures the vacuum of the pre-stripping section and the plate tower section; c. It prevents the leakage of air from the lower layer directly through the high-temperature packing layer to oxidize the oil.

[0042] 3. Make full use of the central tube space in the tower and integrate the heat exchange of hot and cold oils into the gas phase exhaust tube in the center of the plate tower. There is no heat loss, no need for insulation, and the finished oil in the tube is cooled by vacuum falling film. The heat exchange efficiency is high, the residence time is short, and there is no mixing back, which effectively avoids the formation of trans acids and harmful polymers. After the cold oil is heat exchanged, it can directly meet the process requirements of low-temperature deodorization, saving the oil heating device.

[0043] 4. The oil pan on the upper part of the built-in heat exchanger eliminates the need for flange sealing, saving manufacturing materials, facilitating disassembly and assembly, and completely preventing the oil from leaking and being oxidized by contact with air.

[0044] 5. The oil buffer tank at the bottom of the heat exchanger is placed outside the tower bottom. On the one hand, it is convenient for maintenance, and on the other hand, it makes full use of the free space inside the tower skirt and makes the pipeline connection more compact.

[0045] 6. The built-in heat exchanger is fixed at the bottom of the tower, with strong bearing capacity, and combined with the movable support on the upper part, it is convenient for expansion and contraction due to heat and cold.

[0046] 7. The concentric annular oil flow channel design on the plate realizes the first-in-first-out principle of oil, avoiding local stagnation of oil and affecting quality.

[0047] 8. The oil final heater uses high-pressure steam as the heat source, which is highly efficient and has no food safety risks. The oil is heated by falling film in the oil pipe, with an extremely short residence time. Hazardous substances do not have time to form, and there is no residue or mixing phenomenon. It is convenient to switch oil products in multiple batches. An expansion flasher is set at the bottom of the heater to achieve preliminary separation of oil and fatty acid vapor. After separation, the gas phase continues to enter the double-shell interlayer annular channel of the rear stripping section tangentially for further separation, ensuring that there is no oil foam entrained in the gas phase. The product obtained after the deodorization distillate is captured has high purity.

[0048] 9. The integrated deodorization tower saves floor space, eliminates a large number of pipeline connections, makes full use of the gravity flow of oil, eliminates unnecessary pump transportation, reduces factory investment and subsequent production and maintenance costs; at the same time, it solves the problems of large fluid resistance along the way, heat loss, and leakage risks of bellows and valves.

[0049] 10. The integrated deodorization tower adopts modular and standardized design, which greatly reduces the cost of the device. At the same time, it can be flexibly configured according to the characteristics of the oil and process index requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The accompanying drawings are only provided for reference and illustration and are not intended to limit the present invention.

[0051] Figure 1 This is a front view of Example 1 of the integrated dual-temperature dual-stripping deodorization tower of the present invention;

[0052] Figure 2 This is a front view of Example 2 of the integrated dual-temperature dual-stripping deodorization tower of the present invention;

[0053] Figure 3 This is a cross-sectional view of a third embodiment of a plate tower section of the present invention;

[0054] Figure 4 is a cross-sectional view of the upper end of the falling film heat exchanger of the present invention;

[0055] Figure 5 A top view of the upper portion of the falling film heat exchanger of the present invention;

[0056] Figure 6This is a flow diagram of an embodiment in which the inner cylinder of the tower tray is separated by partitions;

[0057] Figure 7 for Figure 1 Enlarged view of the upper middle part;

[0058] Figure: 1. Plate tower; 1a. Compartment bottom plate; 1b. Plate tower oil outlet; 1c. Skirt; 2. Pre-degassing chamber; 2a. Decolorized oil inlet; 2b. Decolorized oil spray pipe; 2c. Pre-degassing vacuum port; 2d. Pre-degassing oil outlet; 3. Center pump; 3a. Vent; 3b. Pump reduction section; 3c. Liquid seal plate; 4. Deodorized oil inlet pipe;

[0059] 5. Falling film heat exchanger; 5a. Oil diffuser; 5b. Oil distribution tray; 5c. Breather pipe; 5d. Support bolts; 5e. Upper tube sheet; 5f. Falling film tubes; 5g. Heat exchanger shell-side inlet; 5h. Heat exchanger shell-side outlet; 5j. Oil buffer tank; 5k. Deodorized oil outlet;

[0060] 6. Tower tray; 6a. Partition inner cylinder; 6b. Radial partition; 6c. Tower tray overflow pipe; 6d. Tower tray drain pipe; 6e. Drain valve; 6f. Tower tray reflux port;

[0061] 7. Stripping pump; 8. Plate tower annular jet pipe; 9. Pre-degassing oil pump; 10. Steam pipe;

[0062] 11. High-temperature stripping tower; 11a. Tangential air inlet; 11b. High-temperature stripping liquid shield; 12. High-temperature stripping oil inlet pipe; 13. Upper oil distribution trough; 13a. Upper oil distribution branch trough; 14. Inner cylinder; 14a. Lower cone bucket of inner cylinder; 14b. Annular stripping steam injection pipe; 14c. Support base; 14d. Movable support; 15. Rear high-temperature packing; 16. Rear stripping oil outlet;

[0063] 17. Low-temperature stripping tower; 18. Low-temperature stripping oil inlet pipe; 19. Lower oil distribution tank; 19a. Lower oil distribution branch tank; 20. Pre-stripping low-temperature packing;

[0064] 21. Decolorization hot oil pipe; 22. High temperature deodorization oil pipe;

[0065] 23. Plate tower oil outlet pump; 24. Plate tower oil outlet pipe; 25. Falling film heater; 26. Gas-liquid separation chamber; 27. Gas phase discharge pipe;

[0066] 28. High-temperature capture tower; 29. ​​High-temperature capture liquid shield; 30. High-temperature section capture liquid inlet pipe; 31. High-temperature liquid distribution tank; 31a. High-temperature liquid distribution branch tank; 32. High-temperature capture packing; 33. High-temperature section capture liquid outlet pipe;

[0067] 34. Low-temperature capture tower; 35. Defoaming device; 36. Low-temperature section capture liquid inlet pipe; 37. Low-temperature liquid distribution tank; 37a. Low-temperature liquid distribution branch tank; 38. Low-temperature capture packing; 39. Low-temperature section capture liquid outlet pipe; 40. Tower main exhaust port. Implementation Method

[0068] In the following description of the present invention, the terms "up", "down", "front", "back", "left", "right", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not mean that the device must have a specific direction.

[0069] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below with reference to specific illustrations.

[0070] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0071] like Figures 1 to 7 As shown, the integrated dual-temperature dual-stripping deodorization tower of the present invention is provided with a plate tower 1, a low-temperature stripping tower 17, a high-temperature stripping tower 11, a high-temperature capturing tower 28 and a low-temperature capturing tower 34 in sequence from bottom to top.

[0072] The plate tower barrel 1 is open at its top, and its lower end is sealed with a plate tower lower head, which is supported to the ground by a skirt 1c. A partition floor 1a is welded to the lower portion of the internal cavity. Together, this, the plate tower lower head, and the plate tower barrel form a pre-degassing chamber 2. A decolorizing oil spray pipe 2b is located at the top of the pre-degassing chamber 2. A decolorizing oil inlet 2a is connected to the decolorizing oil spray pipe 2b and is located on the upper sidewall of the pre-degassing chamber 2. A pre-degassing vacuum port 2c is also located on the upper sidewall of the pre-degassing chamber 2, and a pre-degassing oil outlet 2d is located at the bottom of the plate tower lower head.

[0073] The bleached oil from the previous process enters the pre-degassing chamber 2 from the bleached oil inlet 2a, and is sprayed out through the bleached oil spray pipe 2b and various nozzles. The entrained air overflows and is extracted and removed from the pre-degassing vacuum port 2c to avoid subsequent high-temperature oxidation of the bleached oil.

[0074] A central air pump 3 is provided upward from the central hole of the compartment bottom plate 1 a along the axis of the plate tower, and the central air pump 3 extends upward to the middle and upper part of the plate tower 1 .

[0075] The falling film heat exchanger 5 is located in the inner cavity of the central exhaust cylinder 3. A plurality of falling film tubes 5f are evenly arranged in the inner cavity of the shell. Each falling film tube 5f runs between the upper tube plate 5e and the lower tube plate. The upper tube mouth of the falling film tube 5f extends from the upper tube plate 5e and is evenly distributed with overflow grooves.

[0076] like Figure 4 、 Figure 5 As shown, a deodorized oil inlet pipe 4 is connected to the central sidewall of the plate tower 1. The inner end of the deodorized oil inlet pipe 4 extends to the axis of the plate tower, and the outlet end curves downward toward the center of the oil distribution pan 5b. An oil dispersing tube 5a is installed at the inner end of the deodorized oil inlet pipe 4 to facilitate uniform overflow into the oil distribution pan 5b. The oil distribution pan 5b is fixed to the upper tube sheet 5e of the falling film heat exchanger 5 via support bolts 5d and is parallel to each other. The oil distribution pan 5b is evenly distributed with multiple oil distribution holes and evenly distributed ventilation pipes 5c that penetrate the oil layer. The gas phase released from the falling film can enter the central exhaust cylinder 3 above through the ventilation pipes 5c.

[0077] The projections of the oil distribution holes are symmetrically distributed around the upper tube openings of each falling film tube array 5f in the shape of an equilateral triangle. The deodorized oil is evenly distributed into the oil distribution pan 5b through the deodorized oil inlet pipe 4 and the oil diverging tube 5a. The oil distribution holes are narrow at the top and wide at the bottom to avoid blockage. The oil distribution holes evenly distribute the oil around the falling film tube array 5f, enter the inner wall of the falling film tube array 5f from the overflow tooth groove, and flow downward to form a falling film.

[0078] The lower end of the shell of the falling film heat exchanger 5 passes through the pre-degassing chamber 2 and the lower head of the plate tower. The lower tube plate reaches the outside of the lower head of the plate tower and is connected to an oil buffer tank 5j below. The oil buffer tank 5j is located in the inner cavity of the skirt 1c. A deodorized oil outlet 5k is provided at the bottom of the oil buffer tank 5j.

[0079] The lower part of the shell of the falling film heat exchanger 5 is provided with a heat exchanger shell side inlet 5g, and the upper part of the shell of the falling film heat exchanger 5 is provided with a heat exchanger shell side outlet 5h; the pre-degassing oil outlet 2d is connected to the inlet of the pre-degassing oil pump 9, and the outlet of the pre-degassing oil pump 9 is connected to the heat exchanger shell side inlet 5g.

[0080] The pre-degassed decolorized oil flows out of the pre-degassed oil outlet 2d at the lower end of the plate tower. It is then pumped by the pre-degassed oil pump 9 into the shell-side inlet 5g at the lower portion of the falling-film heat exchanger housing. It then flows upward along the shell side of the falling-film heat exchanger 5, exchanging heat in countercurrent with the deodorized oil film on the tube side. After its temperature drops, the deodorized oil enters the oil buffer tank 5j for temporary storage before flowing out of the deodorized oil outlet 5k at the bottom of the oil buffer tank 5j. After being preheated, the decolorized oil flows out of the shell-side outlet 5h at the upper portion of the falling-film heat exchanger housing. This outlet 5h is equipped with an expansion joint and extends radially outside the plate tower. It then flows through the decolorized hot oil pipe 21 to the low-temperature stripping unit.

[0081] The annular space between the central vacuum pump 3 and the plate tower 1 is equipped with multiple trays 6, each of which is equipped with a stripping pump 7. A plate tower annular air duct 8 is located above the compartment floor 1a, and a plate tower oil outlet 1b is located on the sidewall of the plate tower 1 in this layer. The plate tower annular air duct 8 and the steam inlet of each stripping pump 7 are connected to a steam pipe 10.

[0082] Typically, the tower trays 6 are arranged in five layers. The top of the falling-film heat exchanger 5 is flush with the top of the third tray 6. The central pumping cylinders 3 in the center of the upper two trays are disconnected from the lower portion. The upper central pumping cylinder 3 is slightly smaller, while the lower central pumping cylinder 3 has a larger inner diameter to accommodate the falling-film heat exchanger 5. An annular gas-phase passage is reserved around the periphery of the falling-film heat exchanger 5. The gas-phase space of each tray 6 layer communicates with the inner cavity of the central pumping cylinder 3 through vents 3a. The vents 3a on each layer are evenly distributed around the circumference of the central pumping cylinder 3 and are located below the upper tray 6.

[0083] Each tower plate is provided with a partition inner tube 6a coaxial with the plate tower barrel, the inner side of the partition inner tube 6a is the inner ring flow channel, and the outer side of the partition inner tube 6a is the outer ring flow channel; a radial partition plate 6b is provided between the outer wall of the central vacuum tube 3 and the inner wall of the plate tower barrel 1, and the outlet of the upper tower plate overflow pipe 6c points to the head end of the inner ring flow channel close to the radial partition plate 6b. The tail end of the partition inner tube 6a close to the other side of the radial partition plate 6b is provided with a notch connected to the head end of the outer ring flow channel, and the tail end of the outer ring flow channel is provided with a tower plate overflow pipe 6c for overflowing to the inner ring flow channel of the next layer.

[0084] Figure 1 The overflow pipes 6c of the tower plates of the outer ring flow channel and the inner ring flow channel are both vertically downward. The first layer of tower plates enters the outer ring flow channel from the gap of the inner ring flow channel, overflows from the outer ring flow channel to the outer ring flow channel of the second layer, enters the inner ring flow channel of this layer at the gap, and then overflows to the inner ring flow channel of the third layer, and enters the outer ring flow channel from the gap of the inner ring flow channel. In this way, the head end and the tail end of each layer alternate in sequence.

[0085] Figure 2 Each inner ring flow channel overflows to the outer ring flow channel of the next layer through the tower plate overflow pipe 6c, and the inner ring flow channel of a certain layer overflows to the outer ring flow channel of the next layer. After a circle of circulation, it enters the inner ring flow channel from the gap and then overflows to the outer ring flow channel of the next layer. The head end and tail end of each layer remain unchanged.

[0086] Figure 3 、 Figure 6 The outer ring flow channels overflow to the inner ring flow channels of the next layer through the tower plate overflow pipe 6c. The outer ring flow channels of a certain layer overflow to the inner ring flow channels of the next layer, circulate around once and enter the outer ring flow channels from the gap, and then overflow to the inner ring flow channels of the next layer. The head and tail ends of each layer remain unchanged.

[0087] Multiple stripping pumps 7 are provided along the inner and outer annular channels, which greatly prolongs the flow length of the oil on each layer of the tray and also prolongs the residence time, ensuring the first-in-first-out of the oil and avoiding local stagnation of the oil, which affects the quality.

[0088] Each tray is tilted, with the outer tray higher and the inner tray lower. A tray drain pipe 6d is connected to the lowest point of each tray. Each tray drain pipe 6d extends outside the plate tower and connects to the lower tray's reflux port 6f via a drain valve 6e. The tray reflux port 6f is located below the liquid level in the outer annular flow channel. Because the overflow height of the tray overflow pipe 6c cannot be adjusted, the liquid level on each tray is fixed. Under certain process conditions, if the liquid level on the tray needs to be adjusted, the drain valve 6e can be opened to allow the oil in the upper layer to drain through the tray drain pipe 6d to the next layer.

[0089] A reduced diameter section 3b is provided at the lower part of the central vacuum cylinder 3, and the upper end of the reduced diameter section 3b is located below the air vent of the bottom layer. The compartment bottom plate 1a plays a role similar to that of the tower tray 6. Since the liquid level of the upper several layers of tower trays is stable, a stripping pump 7 with higher liquid level requirements is set for stripping.

[0090] The bottom compartment floor 1a uses a plate tower annular jet pipe 8 for the final stripping stage, making it easy to adjust the liquid level in this layer. A reduced diameter section 3b of the pump is provided in this layer to expand the oil storage capacity above the bottom compartment floor 1a and provide a better buffering effect.

[0091] A liquid seal disc is installed at the lower end of the reduced diameter section 3b of the vacuum pump. Condensate from the central vacuum pump's gas phase flows directly into the disc under gravity, overflowing downward to form a liquid seal with the gas phase space in the pre-degassing chamber 2. A drainage hole is provided on the liquid seal disc. During normal operation, condensate overflows from the upper end of the liquid seal disc. When the system is stopped, the drainage hole can slowly drain the liquid from the liquid seal disc.

[0092] The gaseous material stripped from the bottom compartment plate 1a of each layer of tower tray 6 enters the annular space between the falling film heat exchanger shell and the central vacuum cylinder 3 from the air vents 3a at the top of each layer, and then moves upward from the edge of the plate tower liquid shield into the low-temperature stripping tower 17 above.

[0093] like Figure 7As shown, the low-temperature stripping tower is stacked above the plate tower 1. The bottom of the low-temperature stripping tower 17 is equipped with a lower grid filled with pre-stripping low-temperature filler 20. A lower oil distribution trough 19 is located at the top of the low-temperature stripping tower 17, extending radially along the tower. A low-temperature stripping oil inlet pipe 18 is located above this lower oil distribution trough 19. The inlet of this low-temperature stripping oil inlet pipe 18 is connected to the shell-side outlet of the heat exchanger via a decolorizing hot oil pipe 21, which delivers preheated decolorized oil at 230-245°C into the lower oil distribution trough. Multiple lower oil distribution branch troughs 19a are connected below the lower oil distribution trough 19. Each lower oil distribution branch trough 19a extends symmetrically and perpendicularly to the tower inner wall, forming a herringbone-shaped oil distribution structure. Oil distribution holes are uniformly distributed at the bottom of each lower oil distribution branch trough 19a, ensuring uniform oil spraying onto the pre-stripping low-temperature filler.

[0094] The decolorized oil at 230-245°C enters the pre-stripping low-temperature filler 20 to form a thin oil film and flows downward, making full use of the stripping steam from the lower plate tower for stripping. Since the fatty acid content in the oil is high in the initial stage, the secondary steam after the plate tower stripping can also achieve a good deacidification effect, which is particularly suitable for oil products with high acid value. At the same time, the oil directly enters the plate tower through the pre-stripping low-temperature filler 20, eliminating the need for pump transportation.

[0095] The conical tower section, which is larger at the top and narrower at the bottom, serves as a transitional connection between the high-temperature stripping tower 11 and the low-temperature stripping tower 17. The interior of the high-temperature stripping tower 11 is equipped with an inner barrel 14, which is filled with a post-heating filler 15, the bottom of which is supported on a grid. The lower end of the inner barrel 14 is equipped with a closed lower cone hopper 14a, the inner cavity of which is equipped with an annular stripping steam injection pipe 14b. The bottom of the lower cone hopper 14a is connected to a post-heating oil outlet 16.

[0096] The bottom of the lower cone bucket 14a of the inner cylinder is supported on the support base 14c, and the support base 14c is welded to the inner wall of the conical tower section. The upper periphery of the inner cylinder body 14 is supported on the inner wall of the high-temperature stripping tower 11 through the movable support 14d.

[0097] An upper oil distribution tank 13 is provided on the upper part of the high-temperature stripping tower 11. The outlet of the high-temperature stripping oil inlet pipe 12 is aligned with the upper oil distribution tank 13, and the heated plate tower oil is sent into the upper oil distribution tank 13. The lower part of the upper oil distribution tank 13 is connected with multiple upper oil distribution branch tanks 13a in a fishbone shape. Each upper oil distribution branch tank raises the temperature packing evenly through the oil distribution hole at the bottom.

[0098] The oil coming out of the plate tower is finally heated to a temperature of 250-265°C. After entering the high-temperature filler 15, a thin oil film is formed for stripping. Since the top of the high-temperature stripping tower 11 is closer to the vacuum pumping port, the vacuum degree is high.

[0099] The oil dripping from the rear high-temperature packing enters the inner drum's lower conical hopper 14a for collection. It is then stripped again by high-temperature steam ejected from annular stripping steam nozzle 14b before exiting through the rear stripping oil outlet 16 at the bottom of the inner drum's lower conical hopper. The high-temperature stripping process is short, and the independent provision of fresh stripping steam enhances mass transfer. This effectively and effectively removes harmful substances such as 3-chloropropane esters, glycidyl esters, plasticizers, and zearalenone, as well as polymers generated during the plate tower thermal decolorization process and free fatty acids produced by oil hydrolysis, thereby improving the quality of the finished oil. The short high-temperature residence time plays a crucial role in suppressing the formation of trans acids and glycidyl esters.

[0100] A high-temperature stripping liquid shield 11b is provided at the upper end of the high-temperature stripping tower 11. An annular gas phase channel is formed between the outer wall of the inner cylinder 14 and the inner wall of the high-temperature stripping tower 11 for the gas phase of the low-temperature stripping tower 17 to flow upward.

[0101] The upper sidewall of the high-temperature stripping column 11 is centrally symmetrically connected to a tangential air inlet 11a, the inner end of which is connected to the . Gaseous material overflowing from the plate tower during heating enters the annular gas phase channel and flows upward with the lower gas phase. When the lower gas phase reaches the top of the high-temperature stripping column 11, it merges with the upper gas phase and flows out from the outer edge of the high-temperature stripping liquid shield 11b.

[0102] The rear stripping oil outlet 16 is connected downwardly to the inlet of the deodorized oil inlet pipe through the high-temperature deodorizing oil pipe 22, the plate tower oil outlet is connected to the inlet of the plate tower oil pump 23, the outlet of the plate tower oil pump 23 is connected to the top oil inlet of the falling film heater 25 through the plate tower oil outlet pipe 24, and the bottom oil outlet of the falling film heater 25 is connected to the inlet of the high-temperature stripping oil inlet pipe 12.

[0103] A gas-liquid separation chamber 26 is provided at the lower end of the falling film heater 25. The bottom oil outlet of the gas-liquid separation chamber 26 is connected to the inlet of the high-temperature stripping oil inlet pipe 12. The upper gas phase port of the gas-liquid separation chamber 26 is connected to the tangential air inlet on the upper side wall of the high-temperature stripping tower through the gas phase discharge pipe 27. The inner port of the tangential air inlet 11a is connected to the annular gas phase channel on the outer periphery of the inner cylinder.

[0104] A high-temperature capturing tower is stacked above the high-temperature stripping tower barrel 11, and a high-temperature liquid distribution tank 31 is provided on the upper part of the high-temperature capturing tower. A high-temperature section capturing liquid inlet pipe 30 for supplying liquid to the high-temperature liquid distribution tank 31 is provided above the high-temperature liquid distribution tank 31, and a plurality of high-temperature liquid distribution branch tanks 31a are connected to the bottom of the high-temperature liquid distribution tank 31, and liquid distribution holes are distributed at the bottom of each high-temperature liquid distribution branch tank 31a; a high-temperature capturing filler 32 is provided below the high-temperature liquid distribution branch tank 31a; a high-temperature stripping liquid blocking cover 11b is provided on the top of the high-temperature stripping tower barrel 11, and a high-temperature section liquid collecting ring is provided below the outer edge of the high-temperature stripping liquid blocking cover 11b, and a high-temperature section capturing liquid outlet pipe 33 is connected to the bottom of the high-temperature section liquid collecting ring.

[0105] A low-temperature capturing tower 34 is stacked above the high-temperature stripping tower 11. A low-temperature liquid distribution tank 37 is provided on the upper part of the low-temperature capturing tower 34. A low-temperature section capturing liquid inlet pipe 36 for supplying liquid to the low-temperature liquid distribution tank 37 is provided above the low-temperature liquid distribution tank 37. A plurality of low-temperature liquid distribution branch tanks 37a are connected to the bottom of the low-temperature liquid distribution tank 37. Liquid distribution holes are distributed at the bottom of each low-temperature liquid distribution branch tank 37a. A low-temperature capturing filler 38 is provided below the low-temperature liquid distribution branch tank 37a. A high-temperature capturing liquid blocking cover 29 is provided on the top of the high-temperature capturing tower. A low-temperature section liquid collecting ring is provided below the outer edge of the high-temperature capturing tower. The bottom of the low-temperature section liquid collecting ring is connected to a low-temperature section capturing liquid outlet pipe 39. A defoaming device 35 is provided above the low-temperature section capturing liquid inlet pipe 36. A tower body total exhaust port 40 is provided at the top center of the low-temperature capturing tower 34.

[0106] Decolorized oil at 105°C from the previous process enters pre-degassing chamber 2 through decolorizing oil inlet 2a. It is then sprayed downward through decolorizing oil spray pipe 2b, removing any remaining oxygen and low-constituent components from the oil and preventing subsequent oxidation at high temperatures. Pre-degassing chamber 2 also features a defined oil storage capacity for short-term buffering and conditioning. The decolorized oil is dispersed through multiple nozzles on decolorizing oil spray pipe 2b into droplets, evenly distributed across the entire cross-section of pre-degassing chamber 2. The volatile oxygen and low-constituent gases are then discharged through pre-degassing vacuum port 2c to the vacuum system.

[0107] The decolorized oil at the bottom of the pre-degassing chamber 2 flows out from the pre-degassing oil outlet 2d, is sent to the shell side inlet 5g of the heat exchanger through the pre-degassing oil pump 9, flows upward along the shell side of the falling film heat exchanger 5, is forced to be deflected multiple times in the shell side, enhances the turbulent effect, and exchanges heat with the high-temperature deodorized oil on the inner wall of the falling film tube 5f, so that the decolorized oil is heated to 230-245°C. The shell side outlet 5h of the heat exchanger is at the top of the shell side of the heat exchanger, and adopts fully welded pipelines and thermal expansion bellows to lead it out of the tower body to prevent leakage.

[0108] The decolorized oil at 230-245°C continues to flow upward along the decolorized hot oil pipe 21 to the low-temperature stripping oil inlet pipe 18 of the pre-stripping packing section, first falls into the lower oil distribution groove 19, and then continues to flow into each lower oil distribution branch groove 19a. It is evenly distributed in the pre-stripping low-temperature packing 20 of the entire cross-section of the low-temperature stripping tower barrel 17 through numerous oil distribution holes. The secondary steam from the plate tower below is used to achieve sufficient gas-liquid contact, quickly removing odorous substances such as free fatty acids, aldehydes, ketones, and unsaturated hydrocarbons in the decolorized oil.

[0109] After the decolorized oil passes through the pre-extracted low-temperature filler 20, it falls by gravity to the plate tower section, first falling to the inner ring flow channel of the first layer of the tower plate and then flowing into the outer ring flow channel. The oil flows through each stripping pump 7 in turn. The steam nozzle at the bottom acts as the stripping pump 7 to drive the oil layer of the tower plate to circulate up and down for deacidification and decomposition of heat-sensitive pigments. During the process, there is no backflow of oil, no short circuit, and no dead corner of flow.

[0110] Finally, the oil on the first tray flows from the tray overflow pipe 6c to the next tray and maintains the oil layer height of the tray. The flow path and stripping process of the oil on the second to fifth trays are the same as those on the first tray. The oil overflows from the fifth tray into the sixth tray, and the flow path on the sixth tray is the same as that on the previous five trays. Since the oil layer height on the sixth tray is flexibly adjusted by the liquid level sensor, a multi-ring plate tower annular jet pipe 8 is used instead of a stripping pump to achieve oil layer stirring and turnover. The contact density between steam and oil is high, and finally the oil flows out from the plate tower oil outlet 1b. After passing through the pre-stripping low-temperature filler 20 and the multi-layer plate tower stripping, the oil temperature will drop by 2-3°C. Each layer of the plate tower is equipped with independent direct steam for stripping, a large-diameter vent and a tray reflux port 6f. A tray drain pipe 6d is connected below the large-diameter vent of each layer. The tray drain pipe 6d discharges oil to the tray reflux port 6f through a drain valve 6e, which facilitates the adjustment of the oil residence time in the plate tower section. After passing through the oil layer, the steam of each layer enters the central vacuum cylinder 3 through the vent 3a and is collected, and then goes upward into the pre-stripping packing section.

[0111] The oil flowing out of the plate tower oil outlet 1b is sent to the plate tower oil outlet pipe 24 by the plate tower oil outlet pump 23, and then sent to the falling film heater 25 at the top of the tower by the plate tower oil outlet pipe 24. Two or three falling film heaters 25 are generally configured according to the output. The oil enters from the top center of the falling film heater 25 and is evenly distributed on the inner wall of the heat exchange tube after distribution. Under the vacuum condition of the inner wall of the tube, it is in the form of a thin film from top to bottom to conduct convection heat transfer with the high-pressure steam outside the tube. After the heating is completed, the temperature rises to 250-265℃, accompanied by the generation of a small amount of fatty acid vapor. The oil and the fatty acid vapor are initially separated in the gas-liquid separation chamber 26 with an expanded diameter at the bottom.

[0112] The separated gas phase enters the tangential air inlet 11a of the high-temperature stripping tower 11 through the gas phase discharge pipe 27, and then enters the annular channel on the outer periphery of the inner cylinder 14 for further separation, ensuring that there is no oil foam entrained in the gas phase, and the product obtained after the deodorization distillate is captured has higher purity.

[0113] Hot oil in the gas-liquid separation chamber 26 flows from the bottom oil outlet into the high-temperature stripping oil inlet pipe 12, first into the upper oil distribution trough 13 and then into the upper oil distribution branch troughs 13a. Through each oil distribution hole, it is evenly distributed into the high-temperature packing 15, where it comes into further contact with steam from below. The inner cylinder 14 is nested within the inner cavity of the high-temperature stripping tower 11. Except for the open top, which is connected to the gas phase, the rest of the space is an independent, enclosed space. During the process, the stripping tower is subjected to optimal high vacuum, high temperature, short duration, and independent, fresh stripping steam. This effectively and rapidly removes harmful substances such as 3-chloropropane esters, glycidyl esters, plasticizers, and zearalenone, as well as polymers generated during the plate tower thermal decolorization process and free fatty acids produced by oil hydrolysis, thereby improving the quality of the finished oil. The short high-temperature residence time plays a crucial role in suppressing the formation of trans acids and glycidyl esters. After the oil flows out from the rear high-temperature filler 15, it falls into the lower cone bucket 14a of the inner tube without stopping. It is only collected and then quickly drawn out of the tower through the rear steam extraction oil port 16 by gravity.

[0114] The deodorized oil temperature after the stripping section filler is 248-263 ℃, flows downward along the high-temperature deodorized oil pipe 22, and enters the deodorized oil inlet pipe 4. The deodorized oil inlet pipe 4 passes through the falling film heat exchange oil shield and enters the oil distribution pan 5b at the top of the built-in falling film heat exchanger 5 in the center of the plate tower. The falling film heat exchange oil shield is used to prevent the condensate in the central vacuum cylinder 3 and the splashing oil from the upper plate tower and the pre-stripping packing tower from mixing into the deodorized oil, while leaving a gas phase vacuum channel to ensure the vacuum falling film cooling of the deodorized oil. After the deodorized oil continues to be distributed through the oil diverging tube 5a, the oil distribution pan 5b and the distribution head at the upper end of the falling film tube 5f, it is evenly distributed on the inner wall of each falling film tube 5f and flows downward rapidly in a thin film shape, with high heat exchange efficiency, short residence time and no mixing back. After heat exchange, the deodorized oil temperature drops to about 120 ℃, and a slight liquid level is left in the oil buffer tank 5j at the bottom of the falling film heat exchanger 5 to ensure continuous and stable operation of the pump. The deodorized oil flows out from the deodorized oil outlet 5k at the bottom of the oil buffer tank 5j and is further cooled by a pump to complete the final deodorized finished oil. At this point, the entire workflow of the decolorized oil in the integrated deodorization tower is completed.

[0115] The recovery of deodorized distillate is also an important component of deacidification and deodorization. In the present invention, the gas phase of the pre-degassing chamber 2 is separately removed to the vacuum system by a vacuum pipe. In order to prevent a small amount of oxygen in the gas phase from passing through the packing layer through the central vacuum cylinder 3 and causing oil oxidation at high temperature, a liquid seal disk is provided at the top center of the pre-degassing chamber 2. At the same time, the condensate of the central vacuum cylinder 3 overflows from the oil-liquid seal disk and returns to the pre-degassing chamber 2.

[0116] Vapor from each tray layer is collected through the central exhaust pipe 3 and directed upward as stripping steam for the pre-stripping packing section. The free fatty acids, aldehydes, ketones, and unsaturated hydrocarbons removed, along with water vapor, flow through the interlayer airflow channel between the inner cylinder 14 and the high-temperature stripping column 11 and upward into the dual-stage distillate capture section. The post-stripping steam then flows upward from the inner cylinder 14 to the high-temperature stripping liquid shield 11b below the dual-stage distillate capture section, where it is combined with the pre-stripping steam and then enters the high-temperature capture packing 32 of the distillate recovery section. The lower layer capture and recovery section uses distillate liquid at approximately 150°C, entering through the high-temperature capture liquid inlet pipe 30 and being sprayed on top. The packing layer provides a large vapor-liquid contact surface area, allowing high-boiling-point components in the deodorized distillate vapor phase, such as VE and phytosterols, to be condensed and captured first, thus condensing and capturing them. These components, which have high economic value, are then discharged through the high-temperature capture liquid outlet pipe 33.

[0117] The distillate vapor then enters the upper layer of low-temperature capture packing 38. Fatty acid liquid at 40-50°C enters through the low-temperature capture liquid inlet pipe 36 and is sprayed upward in the same manner. After passing through the low-temperature capture packing 38, the fatty acid vapor in the vapor phase is condensed and captured, then flows out of the low-temperature capture liquid outlet pipe 39 for recycling. The tower's main exhaust port 40 at the top is connected to the vacuum system. After the dual-stage capture process, the remaining water vapor and a small amount of air in the vapor phase are intercepted by the defoamer 35 to remove fine liquid foam, then discharged from the main exhaust port 40 and pumped into the vacuum system.

[0118] The above description is only a preferred embodiment of the present invention, which shows and describes the basic principles, main features and advantages of the present invention, but does not limit the scope of patent protection of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. In addition to the above embodiments, the present invention may have other implementation modes without departing from the spirit and scope of the present invention. The present invention may also have various changes and improvements, and all technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the present invention. The scope of protection required by the present invention is defined by the attached claims and their equivalents. Technical features not described in the present invention can be achieved by or using existing technologies, and will not be described here.

Claims

1. An integrated dual-temperature dual-stripping deodorization tower, comprising a skirt supported on the ground, characterized in that: The plate tower, the low-temperature stripping tower and the high-temperature stripping tower are stacked on the skirt from bottom to top, and the plate tower is provided with: The cavity bottom plate is located at the lower part of the inner cavity of the plate tower; The pre-degassing chamber is formed by the bottom plate of the compartment and the lower head of the plate tower, and is evenly distributed with decolorizing oil spray pipes on the top. The upper side wall is provided with a decolorizing oil inlet and a pre-degassing vacuum port. The decolorizing oil inlet is connected to the decolorizing oil spray pipe, and the lower part of the lower head of the plate tower is provided with a pre-degassing oil outlet. A central vacuum cylinder extends upward from the central hole of the compartment bottom plate to the middle and upper part of the plate tower cylinder, and is provided with a central cylinder oil shield on the top; The tower tray is located in the annular space between the central vacuum cylinder and the plate tower cylinder, and is provided with multiple layers from top to bottom and each is equipped with a steam stripping pump; Falling film heat exchanger, the shell is located in the central vacuum cylinder, the inner cavity of the shell is provided with falling film tubes, the falling film tubes run through the upper tube sheet and the lower tube sheet, an oil distribution pan is provided above the upper tube sheet; the lower end of the shell passes through the lower head of the plate tower and is connected to an oil buffer tank below the lower tube sheet, and a deodorized oil outlet is provided at the bottom of the oil buffer tank; a deodorized oil inlet pipe connected to the side wall of the plate tower barrel and with its outlet end pointing to the center of the oil distribution pan; A plate tower oil outlet is connected to the side wall of the plate tower barrel and is located above the compartment bottom plate; The vent holes are evenly distributed on the circumference of the central vacuum cylinder and enable the gas phase space of the tower plate to communicate with the inner cavity of the central vacuum cylinder.

2. The integrated dual-temperature dual-stripping deodorization tower according to claim 1, characterized in that: The lower part of the shell of the falling film heat exchanger is provided with a heat exchanger shell side inlet, and the upper part of the shell of the falling film heat exchanger is provided with a heat exchanger shell side outlet and extends out of the plate tower barrel; the pre-degassing oil outlet is connected to the inlet of the pre-degassing oil pump, and the outlet of the pre-degassing oil pump is connected to the heat exchanger shell side inlet.

3. The integrated dual-temperature dual-stripping deodorization tower according to claim 2, characterized in that: A lower oil distribution trough is radially provided at the upper end of the low-temperature stripping tower barrel, and a low-temperature stripping oil inlet pipe for supplying oil to the lower oil distribution trough is provided above the lower oil distribution trough, and the shell-side outlet of the heat exchanger is connected to the inlet of the low-temperature stripping oil inlet pipe upward through a decolorization hot oil pipe; a plurality of lower oil distribution branch troughs are connected below the lower oil distribution trough, and the bottom of each lower oil distribution branch trough is provided with oil distribution holes; a pre-stripping low-temperature filler is provided below the lower oil distribution branch trough, and the bottom of the pre-stripping low-temperature filler is supported on the lower grid, and the lower grid is supported on the bottom inner wall of the low-temperature stripping tower barrel.

4. The integrated dual-temperature dual-stripping deodorization tower according to claim 3, characterized in that: Each of the tower plates is provided with a partitioned inner tube coaxial with the plate tower barrel, the inner side of the partitioned inner tube is the inner ring flow channel, and the outer side of the partitioned inner tube is the outer ring flow channel; a radial partition is provided between the outer wall of the central vacuum tube and the inner wall of the plate tower barrel; the outlet of the overflow pipe of the upper tower plate turns to point to the head end of the inner ring flow channel close to the radial partition side, and the tail end of the partitioned inner tube close to the other side of the radial partition is provided with a notch connected to the head end of the outer ring flow channel.

5. The integrated dual-temperature dual-stripping deodorization tower according to claim 4, characterized in that: The tail end of the outer ring flow channel is provided with a tower plate overflow pipe for overflowing to the head end of the inner ring flow channel of the next layer; or the head end of the inner ring flow channel is provided with a tower plate overflow pipe for overflowing to the tail end of the outer ring flow channel of the next layer; or the tail end of the outer ring flow channel is provided with a tower plate overflow pipe for overflowing to the tail end of the outer ring flow channel of the next layer, and the head end of the inner ring flow channel is provided with a tower plate overflow pipe for overflowing to the head end of the inner ring flow channel of the next layer.

6. The integrated dual-temperature dual-stripping deodorization tower according to claim 4, characterized in that: A conical guide ring is provided below the lower grid to guide the oil into the inner annular flow channel on the tower plate.

7. The integrated dual-temperature dual-stripping deodorization tower according to claim 4, 5 or 6, characterized in that: Each of the tower trays is tilted with the outside higher and the inside lower, and a tower tray drain pipe is connected to the lowest point of the tower tray. The tower tray drain pipe of each layer extends to the outside of the plate tower barrel and is connected to the tower tray reflux port of the lower layer through a drain valve. The tower tray reflux port is located below the liquid level of the outer ring flow channel.

8. The integrated dual-temperature dual-stripping deodorization tower according to claim 1, characterized in that: A plate tower annular air injection pipe is provided above the compartment bottom plate.

9. The integrated dual-temperature dual-stripping deodorization tower according to claim 1, characterized in that: A reduced diameter section is provided at the lower part of the central vacuum cylinder, the upper end of which is located below the air vent of the bottom layer, and a liquid sealing disk is provided at the lower end of the reduced diameter section of the vacuum cylinder, which has a drainage hole.

10. The integrated dual-temperature dual-stripping deodorization tower according to claim 1, characterized in that: An oil dispersing cylinder for evenly overflowing toward the oil distribution pan is provided below the inner end of the deodorized oil inlet pipe. The oil distribution pan is fixed above the upper tube plate of the falling film heat exchanger by supporting bolts. The oil distribution pan is evenly distributed with a plurality of oil distribution holes that are narrow at the top and wide at the bottom. The projections of the oil distribution holes are symmetrically distributed around the upper tube openings of each falling film tube array in the form of a regular triangle; and air permeable pipes that pass through the oil layer are evenly distributed on the oil distribution pan.

11. The integrated dual-temperature dual-stripping deodorization tower according to claim 3, characterized in that: The inner cavity of the high-temperature stripping tower is provided with an inner cylinder coaxial therewith, the inner cavity of the inner cylinder is provided with a post-high-temperature filler, the bottom of the inner cylinder is provided with a closed inner cylinder lower cone bucket, the inner cavity of the inner cylinder lower cone bucket is provided with an annular stripping steam injection pipe, the bottom of the inner cylinder lower cone bucket is connected to the post-stripping oil outlet, and an annular gas phase channel is formed between the outer wall of the inner cylinder and the inner wall of the high-temperature stripping tower; An upper oil distribution groove is radially provided above the post-raising temperature packing, and a high-temperature steam stripping oil inlet pipe for supplying oil to the upper oil distribution groove is provided above the upper oil distribution groove; a plurality of upper oil distribution branch grooves are connected below the upper oil distribution groove, and the bottom of each upper oil distribution branch groove is provided with oil distribution holes for evenly distributing oil to the post-raising temperature packing.

12. The integrated dual-temperature dual-stripping deodorization tower according to claim 11, characterized in that: The post-stripping oil outlet is connected downwardly to the inlet of the deodorized oil inlet pipe through a high-temperature deodorizing oil pipe, the plate tower oil outlet is connected to the inlet of a plate tower oil outlet pump, the outlet of the plate tower oil outlet pump is connected to the top oil inlet of the falling film heater through a plate tower oil outlet pipe, and the bottom oil outlet of the falling film heater is connected to the inlet of the high-temperature stripping oil inlet pipe.

13. The integrated dual-temperature dual-stripping deodorization tower according to claim 12, characterized in that: A gas-liquid separation chamber is provided at the lower end of the falling film heater, the bottom oil outlet of the gas-liquid separation chamber is connected to the inlet of the high-temperature stripping oil inlet pipe, the upper gas phase port of the gas-liquid separation chamber is connected to the tangential air inlet of the upper side wall of the high-temperature stripping tower through a gas phase discharge pipe, and the inner port of the tangential air inlet is connected to the annular gas phase channel on the outer periphery of the inner cylinder.

14. The integrated dual-temperature dual-stripping deodorization tower according to claim 13, characterized in that: The falling film heaters are symmetrically provided on both sides of the high-temperature stripping tower, and the tangential air inlets are also symmetrically provided on the upper side wall of the high-temperature stripping tower.

15. The integrated dual-temperature dual-stripping deodorization tower according to claim 1, characterized in that: A high-temperature capturing tower is stacked above the high-temperature stripping tower barrel, a high-temperature liquid distribution tank is provided on the upper part of the high-temperature capturing tower, a high-temperature section capturing liquid inlet pipe for supplying liquid to the high-temperature liquid distribution tank is provided above the high-temperature liquid distribution tank, a plurality of high-temperature liquid distribution branch tanks are connected to the bottom of the high-temperature liquid distribution tank, and liquid distribution holes are distributed at the bottom of each high-temperature liquid distribution branch tank; a high-temperature capturing filler is provided below the high-temperature liquid distribution branch tank; a high-temperature stripping liquid blocking cover is provided on the top of the high-temperature stripping tower barrel, a high-temperature section liquid collecting ring is provided below the outer edge of the high-temperature stripping liquid blocking cover, and a high-temperature section capturing liquid outlet pipe is connected to the bottom of the high-temperature section liquid collecting ring.

16. The integrated dual-temperature dual-stripping deodorization tower according to claim 15, characterized in that: A low-temperature capturing tower is stacked above the high-temperature stripping tower cylinder, a low-temperature liquid distribution trough is provided on the upper part of the low-temperature capturing tower, a low-temperature section capturing liquid inlet pipe for supplying liquid to the low-temperature liquid distribution trough is provided above the low-temperature liquid distribution trough, a plurality of low-temperature liquid distribution branch troughs are connected to the bottom of the low-temperature liquid distribution trough, and liquid distribution holes are distributed at the bottom of each low-temperature liquid distribution branch trough; a low-temperature capturing filler is provided below the low-temperature liquid distribution branch trough; a high-temperature capturing liquid blocking cover is provided on the top of the high-temperature capturing tower, a low-temperature section liquid collecting ring is provided below the outer edge of the high-temperature capturing, and a low-temperature section capturing liquid outlet pipe is connected to the bottom of the low-temperature section capturing liquid outlet pipe; a defoaming device is provided above the low-temperature section capturing liquid inlet pipe, and a total exhaust port of the tower body is provided at the top center of the low-temperature capturing tower.

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