An ethanol oxidation device for producing acetaldehyde and a production process thereof

Abstract

The present application relates to a kind of ethanol oxidation production device and its production process for acetaldehyde, comprising: processing unit, evaporation tower, reactor, absorption tower, rectifying tower and recovery tower;Wherein, the processing unit import is respectively connected with air source and raw material source, and the processing unit outlet is connected with the evaporation tower;The evaporation tower bottom is connected with the reactor cooling section, and the reactor cooling section outlet is connected with the evaporation tower middle part, and the evaporation tower top is connected with the reactor reaction section;The reactor cooling section is connected with the absorption tower bottom, and the absorption tower top is connected with desalted water source;The absorption tower bottom is connected with the rectifying tower middle part;The rectifying tower bottom is connected with the recovery tower.The problems, such as the need to consume a large amount of steam and low catalyst conversion rate in the prior art, are solved.

Description

Technical Field

[0001] This invention relates to the field of chemical equipment, and in particular to a production apparatus and process for the oxidation of ethanol to acetaldehyde. Background Technology

[0002] Ethanol oxidation is an industrial process for preparing acetaldehyde. It involves the reaction of ethanol with oxygen in the presence of a catalyst (such as a silver or copper-based catalyst) to produce acetaldehyde. The reaction formula is: 2C2H5OH + O2 → 2CH3CHO + 2H2O.

[0003] In traditional schemes, each unit, such as evaporation, reaction, and separation, operates independently, resulting in high energy consumption in the production process. In the acetaldehyde preparation process, the evaporation unit requires a large amount of steam, and the catalyst conversion rate of the reaction unit is low.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a production apparatus and process for the oxidation of ethanol to acetaldehyde, so as to solve the problems of high steam consumption and low catalyst conversion rate in the prior art.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: A production apparatus for the oxidation of ethanol to acetaldehyde; It includes: a processing unit, an evaporator, a reactor, an absorption tower, a distillation tower, and a recovery tower; wherein, the inlet of the processing unit is connected to an air source and a raw material source respectively, and the outlet of the processing unit is connected to the evaporator; the bottom of the evaporator is connected to the cooling section of the reactor, the outlet of the cooling section of the reactor is connected to the middle part of the evaporator, and the top of the evaporator is connected to the reaction section of the reactor; the cooling section of the reactor is connected to the bottom of the absorption tower, and the top of the absorption tower is connected to a demineralized water source; the bottom of the absorption tower is connected to the middle part of the distillation tower; and the bottom of the distillation tower is connected to the recovery tower.

[0007] A further technical solution is that the processing unit includes: a first conveying device for conveying air, a second conveying device for conveying raw materials, and a preheating device for heating the raw materials; wherein the output end of the first conveying device and the output end of the second conveying device are connected to the evaporation tower; and the preheating device is connected between the output end of the second conveying device and the evaporation tower.

[0008] A further technical solution includes: a filter, a cooler, a storage tank, and a preheater; the filter is connected to the top of the evaporation tower and the reaction section of the reactor respectively; the cooler is connected to the cooling section of the reactor and the bottom of the absorption tower respectively; the bottom of the absorption tower is connected to the storage tank, the cooler, the preheating device, and the preheater in sequence from the middle of the distillation tower.

[0009] A further technical solution is that the top of the distillation column is connected to a first condenser, the outlet of the first condenser is connected to a first separator, the outlet of the first separator is connected to a first reflux tank, the first reflux tank discharges product and is connected to the distillation column; the top of the recovery column is connected to a second condenser, the outlet of the second condenser is connected to a second separator, the outlet of the second separator is connected to a second reflux tank, and the outlet of the second reflux tank is connected to the recovery column and the second conveying device respectively.

[0010] A further technical solution is that the evaporation tower includes an evaporation cylinder, a first stacked plate stacked in parallel on the upper part of the evaporation cylinder, a second stacked plate stacked in parallel on the lower part of the evaporation cylinder, and a condenser tube disposed in the evaporation cylinder; The reactor includes a reaction cylinder, a steam cylinder, a steam plate connected in parallel within the steam cylinder, a mesh cylinder penetrating the steam plate, a third stacked plate stacked in parallel within the reaction cylinder, and a steam package connected to the top of the steam cylinder; In this configuration, adjacent first stacked plates form interconnected first channels, and adjacent second stacked plates are staggered and bent to form interconnected second channels; one channel connects the steam package and the condenser tube respectively, and the other channel connects the second channel and the mesh cylinder respectively; The mesh cylinder connects the adjacent steam plates, and the mesh cylinder is filled with catalyst; a third channel is formed on the adjacent third stack plates, one of which is connected to the second channel end to end, and the other of which is connected to the mesh cylinder and the absorption tower respectively.

[0011] A further technical solution includes a cooler connected to the reactor; the cooler includes a frame box, cooling channels that are reciprocated and laid in the frame box, and baffles that are arranged alternately in the cooling channels; wherein, a cooling space is formed between the frame box and the cooling channels; the cooling channels are respectively connected to the third channel and the absorption tower; the cooling space is respectively connected to the condenser, the storage tank and the preheating device.

[0012] A production process for an ethanol oxidation to acetaldehyde production apparatus includes the following steps: Pretreatment step: A second conveying device conveys raw materials into a preheating device, the preheating device heats the raw materials, and the heated raw materials enter an evaporation tower; A first conveying device conveys air into the evaporation tower; Circulating evaporation steps: Ethanol from the bottom of the evaporation tower enters from the reactor cooling section and is preheated to 60-70°C, then refluxes to the middle of the evaporation tower; after preheating, the ethanol and air come into contact and are heated, causing the raw material to vaporize; unreacted ethanol re-enters the reactor cooling section to repeat the above steps; after the reaction, ethanol and air are mixed and heated in the upper part of the evaporation tower to form a mixed gas that enters the filter for filtration; Reaction steps: After filtration, the mixed gas enters the reaction section of the reactor to undergo a catalytic reaction; the reaction temperature is 500-550℃; after the reaction, the mixed gas is discharged from the cooling section of the reactor. Multi-stage absorption process: After the reaction, the mixed gas is cooled by a cooler and then enters the absorption tower; the mixed gas undergoes multi-stage circulation absorption through the packing material of the absorption tower to produce a dilute acetaldehyde solution which enters the storage tank; the temperature at the bottom of the absorption tower is 20-22℃, and the temperature at the top of the absorption tower is 4-6℃. Pressurized distillation steps: Dilute acetaldehyde solution is gradually preheated from the storage tank through a cooler, a preheating device, and a preheater, and enters from the middle of the distillation column; the distillation column generates a gas phase that enters the first condenser to form the first condensate, which enters the first separator for separation and is collected in the first reflux tank, with part of it entering the distillation column and part forming the product; Recovery steps: The liquid discharged from the bottom of the distillation column enters the recovery column, the recovery column generates a gas phase which enters the second condenser to form the second condensate, enters the second separator for separation and is collected in the second reflux tank, part of which enters the recovery column and part of which enters the second conveying device.

[0013] Compared with the prior art, the beneficial technical effects of the present invention are as follows: (1) The unvaporized ethanol in the evaporator is preheated by the residual heat of the mixed gas in the reactor cooling section, and then enters the middle of the evaporator to form a cycle. Only the vaporized ethanol can come into contact with the steam for heating, thereby reducing the amount of steam consumed in the evaporator; the reactor reaction section uses the reaction heat to convert the boiler feedwater into steam, which can be used to heat the evaporator, distillation tower and recovery tower, realizing the reuse of steam and reducing the consumption of steam; the electrolytic silver catalyst is composed of multiple particle sizes, which can improve the ethanol conversion rate and reduce the amount of by-products: acetic acid and diethyl ether generated.

[0014] (2) Under pressure, the boiling point of acetaldehyde in the distillation column rises to 80-90℃. After distillation, the dilute acetaldehyde solution produces a gas phase, which is discharged from the top of the distillation column and enters the first condenser. It condenses upon contact with cooling water and then enters the first separator for separation. The condensate is collected in the first reflux tank. The first reflux tank uses the first reflux pump to return part of the acetaldehyde to the distillation column and collects part of the acetaldehyde as a product. The bottom of the distillation column is connected to the recovery column. The material containing ethanol and water at the bottom of the distillation column is pumped into the recovery column. The pressure distillation in the distillation column increases the condensation temperature of the dilute acetaldehyde solution. Conventional cooling water can be used instead of low-temperature water in the first condenser to avoid consuming low-temperature water.

[0015] (3) The reciprocating alternating path changes the direction of the first channel to the opposite direction, which creates greater resistance to the flowing medium in the first channel. The long residence time in the path allows for sufficient heat exchange and improves the heat exchange effect. The spiral path changes the direction of the first channel smoothly with low resistance. The flowing medium in the first channel maintains a certain speed and maintains the heat exchange efficiency. The reciprocating alternating path and the spiral path can be combined to control the flow of the flowing medium in the first channel, thereby improving the heat exchange efficiency while maintaining the required heat exchange effect.

[0016] (4) After preheating, the ethanol and the ethanol rising from the bottom of the evaporation tower flow in the second channel and come into contact and vaporize. The guide is cross-shaped, so that the medium in the second channel flows along the surface of the guide, which increases the contact area of ​​the medium and the vaporization effect is obvious. The middle position of the upper end of the cross-shaped guide can accumulate some of the preheated ethanol, which preheats the guide to a certain extent and shortens the vaporization time.

[0017] (5) The positions of the through holes on the adjacent steam plates are staggered, so that the positions of the mesh cylinders on the adjacent steam plates are staggered. This allows the mixed gas to react with the catalyst and then mix between the adjacent steam plates before it comes into contact with the catalyst again, ensuring uniform contact and reaction between the mixed gas and the catalyst. The mesh structure of the mesh cylinder can fill the catalyst and allow the mixed gas to pass through, thus filtering the mixed gas without the need for a separate filter. The mixed gas and the catalyst come into contact multiple times, and multiple filtrations are completed during the contact process, ensuring the filtration effect. The steam in the steam bag can enter the first channel, allowing the mixed gas and steam in the evaporation tower to exchange heat and complete the recycling of steam. At the same time, the steam in the steam bag can also provide heat for the evaporation tower, distillation tower and recovery tower. When the mixed gas is between the adjacent steam plates, the adjacent steam plates separate the mixed gas. The mixed gas contacts the inner surface of the steam cylinder and the surface of the steam plate, which can maintain the ambient temperature at the set reaction temperature. The mixed gas needs to flow through the mesh cylinder and contact the catalyst before it can flow, so that the mixed gas and the catalyst can react fully.

[0018] (6) Unvaporized ethanol flows from bottom to top along the third channel and flows back into the second channel after being heated to complete the cycle. The heat exchange between the mixed gas and the unvaporized ethanol reduces the amount of steam consumed. The mixed gas flows from top to bottom in another third channel. The mixed gas enters the cooler, and the condensate in the condenser tube enters the cooler for cooling. The acetaldehyde, unreacted ethanol and water vapor in the mixed gas condense into liquid phase and enter the absorption tower, thus completing the reuse of the condensate.

[0019] (7) The surface of the reciprocating curved cooling channel forms multiple curved surfaces, which increases the contact area between the cooling channel and the medium in the cooling space and improves the heat exchange and cooling efficiency in the cooling space. Attached Figure Description

[0020] Figure 1 A schematic diagram of the production apparatus for ethanol oxidation to acetaldehyde according to the first embodiment of the present invention is shown.

[0021] Figure 2 It shows Figure 1 Enlarged structural diagram of the first conveying device, the second conveying device, and the preheating device.

[0022] Figure 3 It shows Figure 1 Enlarged structural diagram of the filter and reactor.

[0023] Figure 4 A schematic diagram of the production apparatus for ethanol oxidation to acetaldehyde according to the second embodiment of the present invention is shown.

[0024] Figure 5 An enlarged structural diagram of the evaporation tower and reactor according to the second embodiment of the present invention is shown.

[0025] Figure 6 An enlarged structural diagram of the first stacked plate is shown when the tilt direction of the plate body of the adjacent first stacked plate is deflected by 90° according to the second embodiment of the present invention.

[0026] Figure 7 The diagram shows a top-view enlarged view of the first stacked plate when the tilt direction of the plate body of the adjacent first stacked plate is deflected by 90° according to the second embodiment of the present invention.

[0027] Figure 8 A top-view enlarged structural diagram of the second stacked plate according to the second embodiment of the present invention is shown.

[0028] Figure 9 An enlarged structural diagram of the cooler according to the second embodiment of the present invention is shown.

[0029] In the attached diagram, the following are the markings: 1. Processing unit; 11. First conveying device; 12. Second conveying device; 121. Ethanol raw material tank; 122. Recovered ethanol tank; 123. Ethanol mixing pump; 124. Ethanol blending tank; 125. Ethanol feed pump; 126. Ethanol filter; 13. Preheating device; 2. Evaporation tower; 21. Filter; 211. Ethanol circulation pump; 212. Steam distributor; 22. Evaporation cylinder; 221. Baffle plate; 23. First stack plate; 24. Second stack plate; 241. Guide component; 25. Condenser tube; 26. First channel; 27. Second channel; 3. Reactor; 31. Cooler; 311. Frame box; 312. Cooling... 313. Channel; 314. Baffle plate; 315. Cooling space; 316. Baffle block; 317. Sealing plate; 32. Steam cylinder; 33. Steam plate; 34. Mesh cylinder; 35. Reaction cylinder; 36. Third stack plate; 37. Steam drum; 4. Absorption tower; 41. Storage tank; 411. Demineralized water tank; 412. Demineralized water pump; 413. Demineralized water cooler; 414. Acetaldehyde liquid cooler; 5. Distillation tower; 51. Preheater; 52. First condenser; 53. First separator; 54. First reflux tank; 541. First reflux pump; 6. Recovery tower; 61. Second condenser; 62. Second separator; 63. Second reflux tank; 631. Second reflux pump. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the device proposed by this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, only for the purpose of conveniently and clearly illustrating the embodiments of this invention. Please refer to the accompanying drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.

[0031] Figure 1 A schematic diagram of the production apparatus for ethanol oxidation to acetaldehyde according to the first embodiment of the present invention is shown. Figure 2 It shows Figure 1 Enlarged structural diagram of the first conveying device, the second conveying device, and the preheating device. Figure 3 It shows Figure 1 Enlarged structural diagram of the filter and reactor. (Combined with...) Figures 1-2As shown, the present invention discloses a production apparatus for ethanol oxidation to acetaldehyde, comprising: a processing unit 1, an evaporation tower 2, a reactor 3, an absorption tower 4, a distillation tower 5, and a recovery tower 6.

[0032] The inlet of processing unit 1 is connected to both an air source and a raw material source, and the outlet of processing unit 1 is connected to evaporation tower 2. Processing unit 1 includes: a first conveying device 11 for conveying air, a second conveying device 12 for conveying raw materials, and a preheating device 13 for heating the raw materials. The output ends of the first conveying device 11 and the second conveying device 12 are connected to evaporation tower 2.

[0033] The first conveying device 11 includes an air filter and an air fan connected in sequence. After being purified by the air filter, the air is conveyed to the bottom of the evaporation tower 2 by the air fan. The second conveying device 12 includes an ethanol raw material tank 121, a recovered ethanol tank 122, an ethanol mixing pump 123, an ethanol blending tank 124, an ethanol feed pump 125, and an ethanol filter 126. The ethanol raw material tank 121 is used to store ethanol raw materials with a purity ≥95%. The recovered ethanol tank 122 is used to store recovered ethanol with a purity of 75-78%. The ethanol raw material tank 121 and the recovered ethanol tank 122 respectively convey the ethanol raw materials and recovered ethanol to the ethanol mixing pump 123, where they are blended with demineralized water to form a raw material with a concentration of 85-88%. The ethanol feed pump 125 conveys the raw material to the ethanol filter 126 to filter out mechanical impurities.

[0034] The preheating device 13 is connected between the output end of the second conveying device 12 and the evaporation tower 2. The preheating device 13 is a wastewater heat exchanger. The filtered raw material enters the preheating device 13 for preheating, and then enters the bottom of the evaporation tower 2.

[0035] The bottom of evaporator 2 is connected to the cooling section of reactor 3, the outlet of the cooling section of reactor 3 is connected to the middle of evaporator 2, and the top of evaporator 2 is connected to the reaction section of reactor 3. The ethanol oxidation to acetaldehyde production unit also includes a filter 21. Filter 21 is connected to both the top of evaporator 2 and the reaction section of reactor 3. The mixed gas discharged from the top of evaporator 2 is filtered by filter 21 and then enters the reaction section of reactor 3. The oxygen-ethanol molar ratio of the mixed gas is 1.05-1.1.

[0036] Ethanol at the bottom of evaporator 2 is pumped to the cooling section of reactor 3 via ethanol circulation pump 211. The ethanol is preheated by contacting the mixed gas in the cooling section of reactor 3, reaching a preheated temperature of 60-70°C before entering the middle of evaporator 2. After preheating, the ethanol vaporizes by contacting the rising ethanol at the bottom of evaporator 2. Unvaporized ethanol is then pumped back to the cooling section of reactor 3 via ethanol circulation pump 211, where it is again preheated to 60-70°C before entering the middle of evaporator 2. This cycle repeats continuously.

[0037] The ethanol oxidation to acetaldehyde production unit also includes a steam distributor 212, whose inlet is connected to both a steam source and the reaction section of reactor 3. The first outlet of the steam distributor 212 is connected to a pipeline located at the top of the evaporation tower 2. Ethanol and the gas form a mixed gas that contacts the pipeline for heating at a temperature of 120-150°C.

[0038] In evaporator 2, the unvaporized ethanol is preheated by the residual heat of the mixed gas in the cooling section of reactor 3, and then enters the middle of evaporator 2 to form a cycle. Only then can the vaporized ethanol come into contact with the steam for heating, thereby reducing the amount of steam consumed in evaporator 2.

[0039] For example, reactor 3 is a fixed-bed reactor. The catalyst bed in the reaction section of reactor 3 includes an electrolytic silver catalyst. The electrolytic silver catalyst has a purity ≥99.99% and a specific surface area >55 cm² / g. The electrolytic silver catalyst consists of a combination of multiple particle sizes, ranging from 8 to 60 mesh. This combination of multiple particle sizes can improve ethanol conversion and reduce the formation of byproducts: acetic acid and diethyl ether.

[0040] The mixed gas first enters the reaction section of reactor 3, and then enters the cooling section of reactor 3. A jacket is formed outside the reaction section of reactor 3, and boiler feedwater is placed inside the jacket to control the reaction temperature at 500-550℃, so that the temperature of the reaction product can be maintained at 200-220℃. The mixed gas, carrying residual heat, preheats the unvaporized ethanol in evaporator 2.

[0041] The reaction section of reactor 3 uses the heat of reaction to convert boiler feedwater into steam, which can be used to heat evaporator 2, distillation tower 5 and recovery tower 6, realizing the reuse of steam and reducing steam consumption.

[0042] The cooling section of reactor 3 is connected to the bottom of absorption tower 4, and the top of absorption tower 4 is connected to a demineralized water source. The ethanol oxidation to acetaldehyde production apparatus also includes a cooler 31 and a storage tank 41. Cooler 31 is connected to both the cooling section of reactor 3 and the bottom of absorption tower 4. For example, cooler 31 is a shell-and-tube cooler.

[0043] The bottom of the cooling section of reactor 3 discharges a mixed gas at a temperature of 140-160℃. The mixed gas contains acetaldehyde, unreacted ethanol, water vapor, and byproducts. The mixed gas then enters cooler 31 for heat exchange with dilute acetaldehyde, cooling water, and chilled water, respectively. Through multi-stage heat exchange, the temperature of the mixed gas is reduced to 20-23℃.

[0044] During the process of the mixed gas temperature decreasing, the acetaldehyde, unreacted ethanol and water vapor in the mixed gas condense into liquid phase and enter the absorption tower 4. After multiple stages of circulation absorption in the absorption tower 4, the dilute acetaldehyde solution is extracted from the bottom of the absorption tower 4 and stored in the storage tank 41.

[0045] The ethanol oxidation to acetaldehyde production unit also includes an acetaldehyde liquid cooler 414. The dilute acetaldehyde solution drawn from the bottom of the absorption tower 4 enters the acetaldehyde liquid cooler 414. Chilled water is introduced into the acetaldehyde liquid cooler 414 to exchange heat with the dilute acetaldehyde solution. After cooling, the dilute acetaldehyde solution re-enters the absorption tower 4 and absorbs acetaldehyde together with the demineralized water.

[0046] The top of the absorption tower 4 is equipped with a water inlet, through which demineralized water flows in. The ethanol oxidation to acetaldehyde production unit also includes a demineralized water tank 411, a demineralized water pump 412, and a demineralized water cooler 413. The demineralized water flows into the demineralized water tank 411 for storage, and the demineralized water pump 412 pumps the demineralized water from the demineralized water tank 411 into the demineralized water cooler 413. In the demineralized water cooler 413, the demineralized water comes into contact with chilled water for heat exchange, cooling the demineralized water to 4-7°C, after which it flows in from the water inlet at the top of the absorption tower 4.

[0047] The ethanol oxidation to acetaldehyde production apparatus also includes a preheater 51. The bottom of the absorption tower 4 is sequentially connected to the storage tank 41, cooler 31, preheating device 13, and preheater 51 in the middle of the distillation tower 5. The bottom of the absorption tower 4 is connected to the middle of the distillation tower 5.

[0048] After the dilute acetaldehyde solution in storage tank 41 is transported to cooler 31, it undergoes a first preheating process upon contact with the gas flowing into cooler 31. The solution is then transported to preheating device 13 for a second preheating, and finally to preheater 51 for a third preheating. Preheater 51 is connected to steam distributor 212, where steam is introduced for preheating. After these three preheating processes, the dilute acetaldehyde solution enters from the middle of distillation column 5. This preheating process between different equipment utilizes waste heat from the equipment, reducing energy consumption.

[0049] The top of the distillation column 5 is connected to the first condenser 52, the outlet of the first condenser 52 is connected to the first separator 53, the outlet of the first separator 53 is connected to the first reflux tank 54, and the first reflux tank 54 discharges the product and is connected to the distillation column 5.

[0050] Cooling water is introduced into the first condenser 52. In the distillation column 5, under pressurized conditions, the boiling point of acetaldehyde rises to 80-90℃. The dilute acetaldehyde solution, after distillation, produces a gaseous phase, which is discharged from the top of the distillation column 5 and enters the first condenser 52. Upon contact with the cooling water, it condenses and then enters the first separator 53 for separation. The condensate is collected in the first reflux tank 54. The first reflux tank 54, through the first reflux pump 541, returns a portion of the acetaldehyde to the distillation column 5, and a portion of the acetaldehyde is collected as a product. The bottom of the distillation column 5 is connected to the recovery column 6. The material containing ethanol and water discharged from the bottom of the distillation column 5 is pumped into the recovery column 6. The pressurized distillation in the distillation column 5 raises the condensation temperature of the dilute acetaldehyde solution. Conventional cooling water can be used in the first condenser 52 instead of cryogenic water, avoiding the consumption of cryogenic water.

[0051] The top of the recovery tower 6 is connected to the second condenser 61, the outlet of the second condenser 61 is connected to the second separator 62, the outlet of the second separator 62 is connected to the second reflux tank 63, and the outlet of the second reflux tank 63 is connected to the recovery tower 6 and the second conveying device 12 respectively.

[0052] Ethanol is recovered through distillation in recovery tower 6. The material containing ethanol and water is distilled to produce a gas phase, which is discharged from the top of recovery tower 6 and enters the second condenser 61 to condense upon contact with cooling water. After separation, it enters the second separator 62, and the condensate is collected in the second reflux tank 63. The second reflux tank 63 uses the second reflux pump 631 to return part of the acetaldehyde to recovery tower 6 and part of the acetaldehyde to recovery ethanol tank 122. The residual liquid at the bottom of recovery tower 6 is transported to the preheating device 13 as a heat exchange source.

[0053] Second embodiment: The production process of the ethanol oxidation to acetaldehyde production unit includes the following steps: Pre-treatment steps: The second conveying device 12 conveys the raw material into the preheating device 13, which heats the raw material. After being heated, the raw material enters the evaporation tower 2. The first conveying device 11 conveys air into the evaporation tower 2.

[0054] The second conveying device 12 mixes the ethanol raw material and the recovered ethanol to prepare a raw material of a preset concentration. After filtration, the raw material is sent to the preheating device 13, where it is heated and then enters the evaporation tower 2. The first conveying device 11 draws in external air through an air fan, which is then filtered before entering the evaporation tower 2.

[0055] Circulating evaporation steps: Ethanol from the bottom of evaporator 2 enters from the cooling section of reactor 3 and is preheated to 60-70°C, then refluxes to the middle of evaporator 2. After preheating, the ethanol and air come into contact and are heated, causing the raw material to vaporize. Unreacted ethanol re-enters the cooling section of reactor 3, repeating the above steps. After the reaction, ethanol and air mix in the upper part of evaporator 2 and are heated to form a mixed gas, which then enters filter 21 for filtration.

[0056] Reaction steps: After filtration, the mixed gas enters the reaction section of reactor 3. It comes into contact with the electrolytic silver catalyst, undergoing a catalytic reaction. A jacket is formed outside the reaction section of reactor 3, with boiler feedwater inside to maintain the reaction temperature at 500-550℃. The mixed gas, carrying residual heat, preheats the unvaporized ethanol in evaporator 2. After the reaction, the mixed gas is discharged from the cooling section of reactor 3.

[0057] Multi-stage absorption process: After the reaction, the mixed gas passes through cooler 31, where it is cooled by heat exchange with dilute acetaldehyde, cooling water, and chilled water respectively. The acetaldehyde, unreacted ethanol, and water vapor in the mixed gas condense into liquid phase and then enter absorption tower 4. The mixed gas then undergoes multi-stage circulation absorption through the packing material of absorption tower 4 to produce a dilute acetaldehyde solution, which enters storage tank 41. The bottom temperature of absorption tower 4 is 20-22℃, and the top temperature of absorption tower 4 is 4-6℃.

[0058] Chilled water and dilute acetaldehyde solution exchange heat in acetaldehyde liquid cooler 414. After cooling, the dilute acetaldehyde solution re-enters absorption tower 4. After cooling, the demineralized water flows in from the water inlet at the top of absorption tower 4. The dilute acetaldehyde solution and the demineralized water absorb acetaldehyde together.

[0059] Pressurized distillation step: The dilute acetaldehyde solution is gradually preheated from the storage tank 41 through the cooler 31, the preheating device 13, and the preheater 51, and then enters the middle of the distillation column 5. The gas phase generated in the distillation column 5 enters the first condenser 52 to form the first condensate, which enters the first separator 53 for separation and is collected in the first reflux tank 54. Part of it enters the distillation column 5, and part of it forms the product.

[0060] Recovery steps: The liquid discharged from the bottom of the distillation column 5 enters the recovery column 6. The gas phase generated in the recovery column 6 enters the second condenser 61 to form the second condensate. After separation in the second separator 62, it is collected in the second reflux tank 63. Part of it enters the recovery column 6, and part of it enters the second conveying device 12 for recycling and reuse.

[0061] Third embodiment: Figure 4 A schematic diagram of the production apparatus for ethanol oxidation to acetaldehyde according to the second embodiment of the present invention is shown. Figure 5 An enlarged structural diagram of the evaporation tower and reactor according to a second embodiment of the present invention is shown. (In conjunction with...) Figure 4 and Figure 5 As shown, the evaporation tower 2 includes a vertically arranged evaporation cylinder 22, a first stacked plate 23 stacked in parallel on the upper part of the evaporation cylinder 22, a second stacked plate 24 stacked in parallel on the lower part of the evaporation cylinder 22, and a condenser tube 25 disposed in the evaporation cylinder 22.

[0062] The reactor 3 includes a reaction cylinder 35, a steam cylinder 32, a steam plate 33 connected in parallel within the steam cylinder 32, a mesh cylinder 34 penetrating the steam plate 33, a third stacked plate 36 stacked in parallel within the reaction cylinder 35, and a steam package 37 connected to the top of the steam cylinder 32.

[0063] In this configuration, adjacent first stacked plates 23 form interconnected first channels 26, and adjacent second stacked plates 24 are staggered and bent to form interconnected second channels 27. One first channel 26 connects to the steam package 37 and the condenser tube 25, while the other first channel 26 connects to the second channel 27 and the mesh cylinder 34.

[0064] A partition 221 is formed in the middle of the evaporator 22, which separates the first channel 26 and the second channel 27. The upper end of the condenser tube 25 is connected to the partition 221 and the upper end of the condenser tube 25 is connected to the first channel 26.

[0065] The first stacked plates 23 form inclined plates, which in turn form the first channels 26. The inclination directions of adjacent first stacked plates 23 are not the same. By combining different inclination directions, the path of the first channels 26 is changed. The mixed gas enters another first channel 26, flows, and then enters the mesh cylinder 34 of the reaction section of reactor 3. During the flow of the mixed gas, it exchanges heat with the steam, absorbing heat and becoming heated. The steam enters another first channel 26, flows, and then enters the condenser 25. During the flow of the steam, it exchanges heat with the mixed gas, and the steam condenses into condensate.

[0066] Figure 6 An enlarged structural diagram of the first stacked plate is shown when the tilt direction of the plate body of the adjacent first stacked plate is deflected by 90° according to the second embodiment of the present invention. Figure 7 This diagram shows a magnified top view of the first stacked plates when the tilt direction of the plates on adjacent first stacked plates is deflected by 90° according to the second embodiment of the present invention. (In conjunction with...) Figures 4-7 As shown, when the inclination directions of adjacent first stacked plates 23 are opposite, the first channel 26 forms an alternating path of leftward and rightward movement, or an alternating path of forward and backward movement. When the inclination direction of adjacent first stacked plates 23 is deflected by 90°, the first channel 26 forms a near-spiral path. The alternating path, by changing the direction of the first channel 26 to the opposite direction, creates greater resistance to the flowing medium within the first channel 26, resulting in a longer residence time and sufficient heat exchange, thus improving the heat exchange effect. The spiral path smoothly changes the direction of the first channel 26 with low resistance, allowing the flowing medium within the first channel 26 to maintain a certain flow velocity and preserve heat exchange efficiency. The alternating path and the spiral path can be combined to control the flow of the medium within the first channel 26, thereby improving heat exchange efficiency while maintaining the required heat exchange effect.

[0067] Figure 8 This is a top enlarged structural view of the second stacked plate according to a second embodiment of the present invention. (In conjunction with...) Figures 4-8 As shown, guide members 241 are formed within the second stacked plate 24, and the guide members 241 are formed by intersecting plates. The guide members 241 on adjacent second stacked plates 24 are staggered, so that the formed second channels 27 are staggered and interconnected. Preheated ethanol and ethanol rising from the bottom of the evaporation tower 2 flow in the second channel 27 and undergo contact vaporization. Because the guide members 241 are in an intersecting shape, the medium in the second channel 27 flows along the surface of the guide members 241, increasing the contact area of ​​the medium and significantly improving the vaporization effect. The middle position at the upper end of the intersecting guide members 241 can accumulate some of the preheated ethanol, preheating the guide members 241 to a certain extent and shortening the vaporization time.

[0068] The condenser tube 25 passes through the middle of the second stack plate 24 in the vertical direction and extends out of the evaporator 22. The condenser tube 25 is connected to the cooler 31. The condensate in the condenser tube 25 enters the cooler 31 for heat exchange and cooling, thus completing the utilization of the condensate.

[0069] The steam cylinder 32 is vertically positioned, and the steam plates 33 are horizontally positioned inside the steam cylinder 32, with the steam plates 33 arranged vertically. The steam plates 33 are connected to the cylinder wall of the steam cylinder 32. Several through holes are formed on the steam plates 33, and mesh cylinders 34 are installed in the through holes. The mesh cylinders 34 connect adjacent steam plates 33, and catalyst is filled inside the mesh cylinders 34.

[0070] The positions of the through holes on adjacent steam plates 33 are staggered, which in turn causes the positions of the mesh cylinder 34 on adjacent steam plates 33 to be staggered. This ensures that after the mixed gas comes into contact with the catalyst and reacts, it mixes between adjacent steam plates 33 before coming into contact with the catalyst again to react, thus ensuring that the mixed gas and the catalyst are in uniform contact and react.

[0071] The mesh structure of the mesh cylinder 34 allows it to be filled with catalyst while also allowing the mixed gas to pass through. The mesh structure of the mesh cylinder 34 filters the mixed gas, eliminating the need for a separate filter. The mixed gas and catalyst come into contact multiple times, with multiple filtration processes occurring during these contactes, ensuring effective filtration.

[0072] Boiler feedwater enters and fills the steam cylinder 32 and steam plates 33. The mixed gas enters and fills the space between adjacent steam plates 33. As the mixed gas flows through the mesh cylinder 34, it reacts with the catalyst and then enters the space between the adjacent steam plates 33 below. Boiler water vaporizes within the steam cylinder 32 and steam plates 33 to form steam, which enters the steam chamber 37 for steam recovery. The steam in the steam chamber 37 can enter the first channel 26, allowing heat exchange between the mixed gas and steam in the evaporator 2, thus recycling the steam. Simultaneously, the steam in the steam chamber 37 can also provide heat for the evaporator 2, distillation column 5, and recovery column 6. When the mixed gas is between adjacent steam plates 33, the adjacent steam plates 33 separate the mixed gas, allowing it to contact the inner surface of the steam cylinder 32 and the surface of the steam plates 33, maintaining the ambient temperature at the set reaction temperature. The mixed gas needs to flow through the mesh cylinder 34 and contact the catalyst to complete its flow, ensuring a complete reaction between the mixed gas and the catalyst.

[0073] A third channel 35 is formed on the adjacent third stack plate 36. One third channel 35 is connected to the second channel 27 end to end, and the other third channel 35 is connected to the mesh cylinder 34 and the absorption tower 4 respectively.

[0074] Guide members 241 are also formed within the third stacked plate 36, and the guide members 241 are formed by intersecting plates. The guide members 241 on adjacent third stacked plates 36 are staggered, so that the formed third channels 35 are staggered and interconnected.

[0075] Unvaporized ethanol flows upwards along the third channel 35, and after being heated, flows back into the second channel 27, completing the cycle. Heat exchange between the mixed gas and the unvaporized ethanol reduces steam consumption.

[0076] The mixed gas flows from top to bottom in another third channel 35. The mixed gas enters the cooler 31, and the condensate in the condenser tube 25 enters the cooler 31 for cooling. The acetaldehyde, unreacted ethanol and water vapor in the mixed gas are condensed into liquid phase and then enter the absorption tower 4, thus completing the reuse of the condensate.

[0077] Figure 9 An enlarged structural diagram of the cooler according to a second embodiment of the present invention is shown. (In conjunction with...) Figures 4-9 As shown, the ethanol oxidation to acetaldehyde production apparatus also includes a cooler 31 connected to reactor 3. The cooler 31 includes a frame box 311, cooling channels 312 reciprocatingly curved within the frame box 311, and baffles 313 staggered within the cooling channels 312. A cooling space 314 is formed between the frame box 311 and the cooling channels 312. The cooling channels 312 are connected to a third channel 35 and an absorption tower 4. The cooling space 314 is connected to a condenser 25, a storage tank 41, and a preheating device 13.

[0078] The frame box 311 is hollow inside, and the two ends of the cooling channel 312 extend out of the frame box 311. Baffles 313 are spaced apart in the cooling channel 312 along the direction of gas flow. When the gas flows, it contacts the baffles 313, which slows down the flow speed of the gas, allowing the gas to be fully cooled by heat exchange in the cooling channel 312.

[0079] A baffle block 315 is formed at the end of the baffle plate 313 away from the cooling channel 312. After the mixed gas comes into contact with the baffle plate 313, the flow velocity slows down. When the mixed gas flows out of the baffle plate 313, it needs to flow along the baffle block 315, which prolongs the flow path of the mixed gas, prolongs the heat exchange time, and ensures the heat exchange and cooling effect of the mixed gas.

[0080] Cooling spaces 314 are located at the upper and lower ends of cooling channel 312, respectively. A sealing plate 316 is formed at the edge of cooling channel 312, connecting to the inner surface of frame box 311 and isolating the two sets of cooling spaces 314. One set of cooling spaces 314 is connected to condenser pipe 25, and the other set of cooling spaces 314 is connected to storage tank 41 and preheating device 13. Condensate flows into one set of cooling spaces 314 through condenser pipe 25, where it exchanges heat with and cools the mixed gas. A dilute acetaldehyde solution flows into the other set of cooling spaces 314 through storage tank 41, where it exchanges heat with and cools the mixed gas before being discharged into preheating device 13.

[0081] The cross-section of the cooling channel 312 is circular or elliptical, which makes the surface of the reciprocatingly curved cooling channel 312 form multiple curved surfaces, increasing the contact area between the cooling channel 312 and the medium in the cooling space 314, and improving the heat exchange and cooling efficiency in the cooling space 314.

[0082] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0083] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A production apparatus for ethanol oxidation to acetaldehyde, characterized in that, include: The system comprises a processing unit (1), an evaporator (2), a reactor (3), an absorption tower (4), a distillation tower (5), and a recovery tower (6); wherein the inlet of the processing unit (1) is connected to an air source and a raw material source, and the outlet of the processing unit (1) is connected to the evaporator (2); the bottom of the evaporator (2) is connected to the cooling section of the reactor (3), the outlet of the cooling section of the reactor (3) is connected to the middle part of the evaporator (2), and the top of the evaporator (2) is connected to the reaction section of the reactor (3); the cooling section of the reactor (3) is connected to the bottom of the absorption tower (4), and the top of the absorption tower (4) is connected to a demineralized water source; the bottom of the absorption tower (4) is connected to the middle part of the distillation tower (5); and the bottom of the distillation tower (5) is connected to the recovery tower (6). The evaporation tower (2) includes an evaporation cylinder (22), a first stacked plate (23) stacked in parallel on the upper part of the evaporation cylinder (22), a second stacked plate (24) stacked in parallel on the lower part of the evaporation cylinder (22), and a condenser (25) disposed in the evaporation cylinder (22). The reactor (3) includes a reaction cylinder (35), a steam cylinder (32), a steam plate (33) connected in parallel within the steam cylinder (32), a mesh cylinder (34) penetrating the steam plate (33), a third stacked plate (36) stacked in parallel within the reaction cylinder (35), and a steam package (37) connected to the top of the steam cylinder (32). Among them, a first channel (26) is formed on the adjacent first stacked plates (23), and a second channel (27) is formed by the adjacent second stacked plates (24) being staggered and bent. One first channel (26) is connected to the steam package (37) and the condenser (25), and the other first channel (26) is connected to the second channel (27) and the mesh cylinder (34). The mesh cylinder (34) connects the adjacent steam plates (33), and the mesh cylinder (34) is filled with catalyst; a third channel is formed on the adjacent third stack plate (36), one of the third channels and the second channel (27) are connected end to end, and the other third channel is connected to the mesh cylinder (34) and the absorption tower (4).

2. The production apparatus for ethanol oxidation to acetaldehyde as described in claim 1, characterized in that, The processing unit (1) includes: a first conveying device (11) for conveying air, a second conveying device (12) for conveying raw materials, and a preheating device (13) for heating raw materials; wherein the output end of the first conveying device (11) and the output end of the second conveying device (12) are connected to the evaporation tower (2); the preheating device (13) is connected between the output end of the second conveying device (12) and the evaporation tower (2).

3. The production apparatus for ethanol oxidation to acetaldehyde as described in claim 2, characterized in that, Also includes: The filter (21), cooler (31), storage tank (41) and preheater (51) are respectively connected to the top of the evaporation tower (2) and the reaction section of the reactor (3); the cooler (31) is respectively connected to the cooling section of the reactor (3) and the bottom of the absorption tower (4); the bottom of the absorption tower (4) is connected to the storage tank (41), the cooler (31), the preheating device (13) and the preheater (51) in sequence from the middle of the distillation tower (5).

4. The production apparatus for ethanol oxidation to acetaldehyde as described in claim 3, characterized in that, The top of the distillation column (5) is connected to the first condenser (52), the outlet of the first condenser (52) is connected to the first separator (53), the outlet of the first separator (53) is connected to the first reflux tank (54), the first reflux tank (54) discharges the product and is connected to the distillation column (5); the top of the recovery column (6) is connected to the second condenser (61), the outlet of the second condenser (61) is connected to the second separator (62), the outlet of the second separator (62) is connected to the second reflux tank (63), the outlet of the second reflux tank (63) is connected to the recovery column (6) and the second conveying device (12) respectively.

5. The production apparatus for ethanol oxidation to acetaldehyde as described in claim 4, characterized in that, It also includes a cooler (31) connected to the reactor (3); the cooler (31) includes a frame box (311), a cooling channel (312) that is laid in the frame box (311) in a reciprocating bend, and baffles (313) that are arranged in opposite staggered manner in the cooling channel (312); wherein, a cooling space (314) is formed between the frame box (311) and the cooling channel (312); the cooling channel (312) is connected to the third channel and the absorption tower (4) respectively; the cooling space (314) is connected to the condenser (25), the storage tank (41) and the preheating device (13) respectively.

6. A production process for an ethanol oxidation to acetaldehyde production apparatus, comprising the ethanol oxidation to acetaldehyde production apparatus as described in claim 5, characterized in that, The process includes the following steps: Pre-treatment step: The second conveying device (12) conveys the raw material into the preheating device (13), the preheating device (13) heats the raw material, and the raw material enters the evaporation tower (2) after being heated; The first conveying device (11) conveys air into the evaporation tower (2); Circulating evaporation steps: Ethanol at the bottom of the evaporation tower (2) enters from the cooling section of the reactor (3) and is preheated to 60-70°C, then refluxes back to the middle of the evaporation tower (2); after preheating, the ethanol and air come into contact and are heated, and the raw material is vaporized; the unreacted material re-enters the cooling section of the reactor (3) to repeat the above steps; after the reaction, ethanol and air are mixed and heated in the upper part of the evaporation tower (2) to form a mixed gas that enters the filter (21) for filtration; Reaction steps: After filtration, the mixed gas enters the reaction section of reactor (3) to undergo a catalytic reaction; the reaction temperature is 500-550℃; after the reaction, the mixed gas is discharged from the cooling section of reactor (3); Multi-stage absorption steps: After the reaction, the mixed gas is cooled by the cooler (31) and then enters the absorption tower (4); after the reaction, the mixed gas is circulated and absorbed in multiple stages through the packing of the absorption tower (4) to produce dilute acetaldehyde solution which enters the storage tank (41); the bottom temperature of the absorption tower (4) is 20-22℃ and the top temperature of the absorption tower (4) is 4-6℃. Pressurized distillation steps: The dilute acetaldehyde solution is gradually preheated from the storage tank (41) through the cooler (31), the preheating device (13) and the preheater (51), and enters from the middle of the distillation column (5); the distillation column (5) generates a gas phase that enters the first condenser (52) to form the first condensate, which enters the first separator (53) for separation and is collected in the first reflux tank (54), part of which enters the distillation column (5) and part of which forms the product; Recovery steps: The liquid discharged from the bottom of the distillation column (5) enters the recovery column (6). The gas phase generated in the recovery column (6) enters the second condenser (61) to form the second condensate. After separation in the second separator (62), it is collected in the second reflux tank (63). Part of it enters the recovery column (6) and part of it enters the second conveying device (12).

Images