CN107778131B - Method for preparing cyclohexanol and cyclohexanone based on multilayer double-loop flow guide cylinder bubble reactor - Google Patents
Method for preparing cyclohexanol and cyclohexanone based on multilayer double-loop flow guide cylinder bubble reactor Download PDFInfo
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Abstract
The invention discloses a method for preparing cyclohexanol and cyclohexanone based on a multilayer double-loop guide cylinder bubble reactor, which comprises the steps of oxidizing cyclohexane by using oxygen-containing gas to generate oxidation liquid containing cyclohexyl hydroperoxide in the multilayer double-loop guide cylinder bubble reactor, extracting the oxidation liquid by using strong base solution to obtain alkaline water phase containing the cyclohexyl hydroperoxide and cyclohexane organic phase, carrying out decomposition reaction on the alkaline water phase containing the cyclohexyl hydroperoxide in the presence of a high-boiling point solvent, distilling the organic phase to obtain a mixture of the cyclohexanol and the cyclohexanone after the decomposition liquid is settled and separated, and returning extracted cyclohexane solution to the process of the cyclohexane oxidation reaction; the method can greatly improve the cyclohexane oxidation selectivity and the reaction efficiency and reduce the cyclohexane distillation energy consumption.
Description
Technical Field
The invention relates to a method for preparing cyclohexanol and cyclohexanone, in particular to a method for preparing cyclohexanol and cyclohexanone by oxidizing cyclohexane with oxygen-containing gas based on a multilayer double-circulating guide cylinder bubble reactor, and belongs to the technical field of KA oil preparation.
Background
Cyclohexane oxidation is generally used for preparing cyclohexanol and cyclohexanone by oxidizing cyclohexane with a gas containing molecular oxygen, firstly generating a cyclohexane oxidation solution containing cyclohexyl hydroperoxide, cyclohexanol and cyclohexanone and other substances, then treating the cyclohexane oxidation solution to decompose the cyclohexyl hydroperoxide in the cyclohexane oxidation solution to generate the cyclohexanol and the cyclohexanone, distilling out unreacted cyclohexane for recycling, and rectifying reaction products for multiple times to obtain the cyclohexanol and the cyclohexanone.
The cyclohexane oxidation reactor is generally a bubble column, and internal components such as a guide shell and the like can be added in the column to improve mass transfer, or stirring can be added. In the bubble column, the liquid phase does not need to be stirred vigorously generally, the gas phase can be highly dispersed in the liquid phase, the liquid holdup and the phase boundary contact surface are larger, the mass transfer and heat transfer efficiency is higher, the reactor is suitable for the conditions of slow chemical reaction and strong heat release, the structure of the reactor is simple, the operation is stable, and the investment and maintenance cost is low. The bubbling reactor with stirring can accelerate mass transfer and heat transfer between gas phase and liquid phase, and is easier to control.
Because the intermediate products of cyclohexyl hydroperoxide, cyclohexanol and cyclohexanone generated by oxidizing cyclohexane by the oxygen-containing gas are easier to oxidize than cyclohexane, and the intermediate products are the required target products, when a single stirring bubbling reactor is used for reaction, the liquid phase is seriously back-mixed, and after a plurality of kettles are connected in series, the flow of the liquid phase is close to plug flow, and compared with a full mixing mode, the intermediate products can be reduced from being further oxidized, so that the yield of the target products is improved. The larger the number of reactors in series, the closer the flow of the liquid phase mixture is to plug flow and the higher the yield of the reaction product. However, in consideration of actual operation and cost, the number of reactors in series is generally 3 to 8, and more reactors are selected from 5 to 6. However, when the number of reactors connected in series is large, the equipment number is huge, so that the initial investment is high, and when the number of reactors connected in series is small, the difference between the actual effect and the plug flow reactor is large, so that the selectivity of the final target product is still low.
ZL200510130561.4 discloses a high gravity reactor-rotating packed bed for preparing cyclohexanone by oxidizing cyclohexane, which can enhance the oxidation process of cyclohexane. The high-gravity reactor can greatly improve the mass transfer speed and the heat transfer speed, but has limited influence on the reaction result due to the improvement of the mass transfer speed in the slow reaction process of which the chemical reaction is a control step, such as the preparation of cyclohexanone by cyclohexane oxidation.
ZL200710098839.3 discloses a microchannel or a microchannel reactor for preparing cyclohexanone by oxidizing cyclohexane, and compared with a bubbling reactor, the microchannel or the microchannel reactor is complex, has larger initial investment, and has no example of industrial production.
CN1834078A discloses a cyclohexane liquid-phase oxidation process, in which liquid-phase cyclohexane is passed through a bubble reactor in a plug flow manner, so as to improve the yield of cyclohexane oxidation. However, unless the residence time of the liquid phase cyclohexane in the reactor is short, such that the upward flow velocity of cyclohexane is close to the rising velocity of bubbles, the rising bubbles will cause turbulence in the liquid, and the flow pattern of the liquid in the bubble column will be far from plug flow and closer to complete flow. In the existing industrial device, the total residence time of liquid materials during cyclohexane oxidation is generally 20-80 minutes, which is converted into 4-16 minutes in each stage of reactor, and the bubbles in the reactor only need to rise from the tower bottom to the tower top for a few seconds. Therefore, it is difficult to achieve a plug flow state of the liquid in the bubble column having a large diameter.
CN1172098 discloses a one-kettle multi-chamber horizontal flow oxidation reactor, wherein baffles are arranged in the reactor to divide materials into a plurality of areas, so that the effect of realizing multi-kettle series connection in a first-stage reactor is achieved. However, the patent does not mention the shape of the reactor nor the corresponding structural dimensions.
ZL200410000231.9 discloses a cyclohexane oxidation reactor, and the casing is vertical straight tube type structure, and gas distributor separates the straight tube section for a plurality of regions, is provided with the internal component packing layer that void fraction and specific surface are big in the straight tube reaction zone, and when the reaction goes on, liquid material passes through the reaction zone with the plug flow mode, and oxygen-containing gas evenly mixes with liquid phase cyclohexane through the tympanic bulla mode, and the gas flows through the reaction zone with liquid phase cyclohexane cocurrent flow. However, the reactor is divided into a plurality of sections of inlet air, when air oxidation is adopted, the gas content of the material at the upper part of the straight cylinder section is greatly increased due to a large amount of nitrogen contained in the gas, and thus the flowing state in the reactor is deteriorated; the gas exiting the gas distributor located in the upper part of the reactor shaft escapes from the liquid phase over a relatively short period of time, and the oxygen content of the offgas may exceed the safety limit due to a too short residence time.
CN103055792A discloses an oscillating tubular reactor for cyclohexane liquid phase oxidation and a use method thereof, wherein a reaction section is formed by connecting a plurality of chambers in series, and one tubular reactor is equivalent to the series connection of a plurality of full mixing kettle reactors, so that the flow mode of the whole reaction fluid is closer to plug flow, and the selectivity of an oxidation intermediate product KA oil is higher. However, the reactor also adopts multi-stage gas inlet, when air oxidation is adopted, the gas content of the material at the upper part of the straight cylinder section is greatly increased due to a large amount of nitrogen contained in the gas, and thus the flowing state in the reactor is deteriorated; the gas exiting the gas distributor located in the upper part of the straight section of the reactor escapes from the liquid phase over a relatively short period of time, and the oxygen content of the off-gas may exceed the safety limits due to a too short residence time.
In order to improve the selectivity of the target product, the oxidation process generally adopts a multi-kettle series connection, cyclohexane flows through each reactor in sequence, cyclohexanol and cyclohexanone in cyclohexane oxidation liquid are maintained in a lower concentration, at present, the domestic industrial device for producing cyclohexanone by oxidizing cyclohexane with air, which is the first step of producing cyclohexanone by oxidizing cyclohexane, is composed of a plurality of stirring bubbling reactors or airlift loop reactors connected in series, as described in Chinese patents ZL200610031689.x, ZL200610031809.6, ZL201120157789.3 and CN 103804161A. The conversion rate of cyclohexane is generally controlled between 3% and 4%, the content of cyclohexyl hydroperoxide is about 3%, and the selectivity of the target product is about 92%. Experience with the process shows that with a 1% increase in cyclohexane conversion, the selectivity to the desired product decreases by about 4%, and thus increasing cyclohexane conversion results in a faster decrease in selectivity.
The cyclohexane oxidation liquid containing about 3% of cyclohexyl hydroperoxide is treated in the decomposition process, the cyclohexyl hydroperoxide is decomposed into cyclohexanol and cyclohexanone and a small amount of byproducts, the prior widely used method is to treat the cyclohexane oxidation liquid with alkaline aqueous solution, acid in the oxidation liquid is neutralized and ester is saponified while the cyclohexyl hydroperoxide is decomposed, so that the decomposition product does not contain acidic substances after the alkaline aqueous phase is separated out by sedimentation, and the subsequent equipment is not corroded, as described in the Chinese patent 01114586.2.
The sum of cyclohexanol and cyclohexanone in the decomposition liquid is about 4%, and a small amount of other oxidation products, wherein cyclohexane with the content of over 95% needs to be distilled in a cyclohexane distillation process, the distilled cyclohexane is about 24 times of the target product, at present, triple effect distillation is adopted in industrial production, and medium pressure steam consumed by cyclohexane distillation is still high. The increase of the cyclohexane oxidation conversion rate can reduce the evaporation amount of cyclohexane, but the increase of the cyclohexane oxidation conversion rate can lead to the reduction of the selectivity of the target product, thereby causing the increase of material consumption, and the decrease of the cyclohexane oxidation conversion rate can improve the selectivity of the target product, but the cyclohexane proportion in the product is higher, and more cyclohexane needs to be distilled out. For example, when the total amount of cyclohexanol and cyclohexanone in the decomposition liquid is about 2%, about 49 times of cyclohexane should be distilled, and it is difficult to compensate for the increased energy consumption for distilling cyclohexane due to the increased selectivity.
Disclosure of Invention
Aiming at the defects of the prior process for preparing cyclohexanone and cyclohexanol, the invention aims to provide a method for preparing cyclohexanol and cyclohexanone by oxidizing cyclohexane with oxygen-containing gas, which has high selectivity, high efficiency and low energy consumption.
In order to achieve the technical purpose, the invention provides a method for preparing cyclohexanol and cyclohexanone based on a multilayer double-loop guide cylinder bubble reactor, which comprises the following steps:
1) oxidizing cyclohexane by oxygen-containing gas in a multilayer double-loop guide shell bubble reactor to obtain oxidizing liquid containing cyclohexyl hydroperoxide; wherein, the conversion rate of cyclohexane oxidation is controlled within the range of 0.5 to 1.5 percent;
2) extracting and separating the oxidizing solution containing the cyclohexyl hydroperoxide by using strong base solution to obtain an alkaline water phase containing the cyclohexyl hydroperoxide and an organic phase containing cyclohexane;
3) adding a high-boiling-point organic solvent into the cyclohexyl hydroperoxide containing alkaline water phase, and then carrying out decomposition reaction on the cyclohexyl hydroperoxide to obtain mixed liquid containing cyclohexanol and cyclohexanone;
the high-boiling-point organic solvent is a non-water-soluble organic solvent which has a boiling point of 200-400 ℃ and does not form an azeotrope with cyclohexanol and/or cyclohexanone;
4) settling and separating the mixed solution containing cyclohexanol and cyclohexanone to obtain an organic phase containing cyclohexanol, cyclohexanone and a high-boiling-point organic solvent and a waste alkali solution;
5) and rectifying and separating the organic phase containing cyclohexanol, cyclohexanone and high-boiling-point organic solvent to obtain a mixed product of cyclohexanol and cyclohexanone and the high-boiling-point organic solvent.
In a preferred embodiment, the multilayer double circular guide cylinder bubble reactor main body comprises a reactor shell and a multilayer double circular guide cylinder. The multilayer double-circular-flow guide cylinder comprises a plurality of layers of double-circular-flow guide cylinders which are coaxially sleeved from inside to outside. The double-circular-flow guide cylinder comprises a guide cylinder main body, an inner circular-flow baffle plate and an outer circular-flow baffle plate; the inner circulation baffle is fixedly arranged on the inner wall of the guide cylinder main body, and the outer circulation baffle is fixedly arranged on the outer wall of the guide cylinder main body; the lower part of the inner annular flow baffle is of a cylindrical structure, and the upper part of the inner annular flow baffle is of a hollow conical structure; the lower part of the outer circulation baffle is of a cylindrical structure, and the upper part of the outer circulation baffle is of a hollow inverted cone structure. The height from the innermost double-circular-flow guide cylinder to the outermost double-circular-flow guide cylinder of the multilayer double-circular-flow guide cylinders is reduced in a gradient manner, and the inner diameter is increased in a gradient manner. The multi-layer double-circulation guide cylinder is fixedly arranged at the bottom in the reactor shell, and water passing gaps are formed between the bottom of each layer of double-circulation guide cylinder and the bottom in the reactor shell. The bottom of the area in the innermost double-circular-flow guide cylinder of the multilayer double-circular-flow guide cylinder is provided with a liquid inlet. The reactor shell lateral wall is equipped with the liquid outlet, reactor shell top is equipped with the gas outlet. The side wall of the reactor shell is provided with an inner annular flow baffle. The bottom of the region in the innermost double-circular-flow guide cylinder of the multilayer double-circular-flow guide cylinder, the bottom of the region between the double-circular-flow guide cylinders of each layer and the bottom of the region between the outermost double-circular-flow guide cylinder and the reactor shell are respectively provided with a gas distributor, and each gas distributor is connected with a gas inlet.
In a preferred scheme, the multilayer double-circular-flow guide cylinder comprises 2-9 layers of double-circular-flow guide cylinders which are coaxially sleeved.
In a preferable scheme, the height difference between two adjacent layers of double-circular flow guide cylinders of the multilayer double-circular flow guide cylinders is 0.01-1 meter, and the distance between two adjacent layers of double-circular flow guide cylinders is 0.1-1 meter.
In a more preferable scheme, the height of the water passing gap is 0.001-0.01 m.
In a preferable scheme, the top of the inner circulation baffle is 0.01-1 meter lower than the top of the guide cylinder main body, and the bottom of the inner circulation baffle is 0.01-1 meter higher than the bottom of the guide cylinder main body; the diameter of the cylindrical structure of the inner circulating baffle is 0.01-0.4 m smaller than that of the corresponding guide cylinder main body; the diameter of the minimum position of the hollow conical structure of the inner annular flow baffle is 0.04-0.8 m smaller than that of the corresponding guide cylinder main body.
In a preferable scheme, the top of the outer circulation baffle is 0.02-1 meter lower than the top of the guide cylinder main body, and the bottom of the outer circulation baffle is 0.02-1 meter higher than the bottom of the guide cylinder main body; the diameter of the cylindrical structure of the outer circulation baffle plate is 0.01-0.4 m larger than the diameter of the guide cylinder main body; the diameter of the hollow inverted conical structure of the outer circulation baffle plate at the maximum position is 0.04-0.8 m larger than the diameter of the guide cylinder main body.
In a preferable scheme, the lower part of the inner ring flow baffle on the side wall of the reactor shell is of a cylindrical structure, and the upper part of the inner ring flow baffle is of a hollow conical structure; the top of the inner circulation baffle is 0.01-1 meter lower than the top of the side wall of the reactor shell, and the bottom of the inner circulation baffle is 0.01-1 meter higher than the bottom of the side wall of the reactor shell; the diameter of the cylindrical structure of the inner circulating baffle is 0.01-0.4 m smaller than the diameter of the shell of the reactor; the diameter of the minimum position of the hollow conical structure of the inner annular flow baffle is 0.04-0.8 m smaller than that of the corresponding reactor shell.
In a preferable scheme, cyclohexane is introduced into the multilayer double-circulation guide cylinder bubbling reactor from the liquid inlet, and the cyclohexane flows from the innermost double-circulation guide cylinder to the outermost double-circulation guide cylinder; one part of cyclohexane flows out layer by layer from the inside to the outside from the water passing gap between the bottom of each layer of double-circulation guide cylinder and the inner bottom of the reactor shell, and the other part of cyclohexane overflows layer by layer from the inside to the outside from the top of each layer of double-circulation guide cylinder; between two adjacent layers of double-circular-flow guide cylinders, part of cyclohexane enters an outer circular-flow area between a guide cylinder main body of an inner layer double-circular-flow guide cylinder and a corresponding outer circular-flow baffle plate thereof, part of cyclohexane enters an inner circular-flow area between a guide cylinder main body of an outer layer double-circular-flow guide cylinder and a corresponding inner circular-flow baffle plate thereof, the cyclohexane in the outer circular-flow area and the inner circular-flow area flows downwards, the cyclohexane in a central area between the inner layer double-circular-flow guide cylinder and the outer layer double-circular-flow guide cylinder flows upwards, and the cyclohexane forms full-mixed flow between the two adjacent layers of double-circular-flow guide cylinders; introducing cyclohexane into the multilayer double-circular-flow guide cylinder bubbling reactor, introducing oxygen-containing gas into the multilayer double-circular-flow guide cylinder bubbling reactor from a gas inlet, dispersing by each gas distributor, fully contacting with the cyclohexane to perform oxidation reaction, leading oxidation liquid containing cyclohexyl hydroperoxide obtained by the reaction out of the multilayer double-circular-flow guide cylinder bubbling reactor from a liquid outlet, and leading tail gas after the reaction out of the multilayer double-circular-flow guide cylinder bubbling reactor from a gas outlet.
In a further preferred scheme, the cyclohexane is preheated to 120-200 ℃ before being introduced into the multilayer double-circular-flow guide cylinder bubbling reactor from the liquid inlet, the reaction temperature in the multilayer double-circular-flow guide cylinder bubbling reactor is kept at 120-200 ℃, and the pressure is 0.4-2.0 MPa (preferably 0.4-1.6 MPa).
In a further preferred embodiment, the oxygen volume percentage concentration of the oxygen-containing gas is 5% to 70%, and the oxygen volume percentage concentration of the oxygen-containing gas introduced into each region between the innermost double circular flow guide cylinder and the outermost double circular flow guide cylinder is sequentially increased.
Preferably, in the step 2), the extraction separation is realized by an extraction tower; a packing layer is filled in the middle part in the extraction tower, the strong alkali solution enters the extraction tower from the upper part of the packing layer, and the oxidizing solution containing the cyclohexyl hydroperoxide enters the extraction tower from the lower part of the packing layer; the strong base solution and the oxidation liquid containing the cyclohexyl hydroperoxide are in countercurrent contact in a packing layer, the cyclohexyl hydroperoxide in the oxidation liquid containing the cyclohexyl hydroperoxide is extracted into the strong base solution to form an alkaline aqueous phase containing the cyclohexyl hydroperoxide and is separated from the bottom of the extraction tower, and a raffinate, namely a cyclohexane-containing organic phase, is separated from the top of the extraction tower.
In a preferable scheme, the temperature of the strong alkali solution entering the extraction tower is 20-80 ℃, and the temperature of the oxidizing solution containing the cyclohexyl hydroperoxide entering the extraction tower is 20-80 ℃; the mass ratio of the strong alkali solution to the oxidizing solution containing cyclohexyl hydroperoxide is 1: 10-10: 1; the operating pressure of the extraction tower is 0.1-1.0 MPa of absolute pressure.
In a more preferable scheme, the strong alkali solution is a sodium hydroxide and/or potassium hydroxide solution with the concentration of 0.5-5 mol/L.
Preferably, the temperature of the cyclohexane-containing organic phase is adjusted to 120-200 ℃, and the oxidation step 1) is returned.
In a preferable scheme, in the step 3), the decomposition reaction is realized by a decomposition kettle, wherein the decomposition kettle comprises a first-stage stirring reaction kettle or more than two stages of stirring reaction kettles connected in series; the alkaline aqueous phase containing the cyclohexyl hydroperoxide and the high boiling point organic solvent firstly enter a first-stage stirring reaction kettle for decomposition reaction, if the decomposition reaction is complete, mixed liquid containing cyclohexanol and cyclohexanone is led out from the first-stage stirring reaction kettle, if the decomposition reaction is incomplete, reaction materials in the first-stage stirring reaction kettle are led into a second-stage or more stirring reaction kettle for decomposition reaction until the decomposition reaction is complete, and the mixed liquid containing cyclohexanol and cyclohexanone is led out from the last-stage stirring reaction kettle.
In a preferable scheme, the temperature of the alkaline aqueous phase containing the cyclohexyl hydroperoxide entering the first-stage stirring reaction kettle is 20-80 ℃, and the temperature of the high-boiling-point organic solvent entering the first-stage stirring reaction kettle is 60-160 ℃; the weight ratio of the high-boiling-point organic solvent to the cyclohexyl hydroperoxide containing alkaline water phase is 1: 10-10: 1, the temperature of each stirring reaction kettle is maintained at 40-140 ℃, and the operating pressure is 0.1-1.0 MPa absolute pressure.
Preferably, the settling separation is realized by a settling separator, the mixed solution containing cyclohexanol and cyclohexanone enters the settling separator from the middle part of the settling separator, standing and settling are carried out in the settling separator, an organic phase containing cyclohexanol, cyclohexanone and high-boiling-point organic solvent is obtained from the top of the settling separator, and the waste alkali solution is obtained from the bottom of the settling separator.
Preferably, the waste alkali solution contains carboxylate, a part of the waste alkali solution is sent to a waste alkali recovery process, and a part of the waste alkali solution is supplemented with strong alkali to adjust the concentration to 0.5-5 mol/L and then returned to the extraction separation process of 2).
In the preferred scheme, the rectification separation is realized by a rectification tower, and the operating pressure of the rectification tower is 0.1-10 kPa; obtaining the mixed product of cyclohexanol and cyclohexanone from the top of the rectifying tower, and recovering the high-boiling-point organic solvent from the bottom of the rectifying tower.
In a preferable scheme, the temperature of the high-boiling-point organic solvent is adjusted to 60-160 ℃, and the step of 3) decomposition reaction is returned.
In a more preferable scheme, the high-boiling-point organic solvent is at least one of water-insoluble alkane, naphthenic hydrocarbon or aromatic hydrocarbon, the boiling point of which is 200-400 ℃, and the water-insoluble alkane, the naphthenic hydrocarbon or the aromatic hydrocarbon does not form an azeotrope with the cyclohexanol and/or the cyclohexanone.
The multilayer double-circular-flow guide cylinder bubble reactor main body comprises a reactor shell and a multilayer double-circular-flow guide cylinder. The reactor shell is cylindrical, the inner diameter of the reactor shell is larger than the outer diameter of the double circular guide cylinder at the outermost layer of the multilayer double circular guide cylinder, and the axis of the reactor shell is superposed with the axis of the multilayer double circular guide cylinder. The multi-layer double-circular-flow guide cylinder is fixedly arranged at the bottom in the reactor shell and divides the reactor shell into a multi-stage annular area.
The bottom edge of the double circular flow guide cylinder of the multilayer double circular flow guide cylinder bubble reactor is fixed with the inner bottom of the reactor shell through a protruding supporting base.
The inner wall of the reactor shell of the multilayer double-circular-flow guide cylinder bubble reactor is fixed with an inner circular-flow baffle plate through a fixing rib.
The inner wall and the outer wall of the guide cylinder main body of the double-circular guide cylinder of the multilayer double-circular guide cylinder bubble reactor are coaxially fixed with an inner circular flow baffle plate and an outer circular flow baffle plate respectively through fixing ribs. And an inner circulation area and an outer circulation area which are communicated up and down are respectively formed between the inner circulation baffle and the guide cylinder main body and between the outer circulation baffle and the guide cylinder main body. The top of the inner circulation baffle is bent inwards to form a positive conical surface, the top of the outer circulation baffle is bent outwards to form an inverted conical surface, and the rest parts of the inner circulation baffle and the outer circulation baffle are straight cylinders.
The multilayer double-circular-flow guide cylinder bubbling reactor disclosed by the invention is provided with fewer layers of double-circular-flow guide cylinders when the diameter of the reactor shell is smaller, and is provided with more layers of double-circular-flow guide cylinders when the diameter of the multilayer double-circular-flow guide cylinder bubbling reactor is larger, and the more the layers are, the closer the flow of the whole reaction liquid is to plug flow.
The height of the double circular guide cylinders in the multilayer double circular guide cylinder bubble reactor is sequentially reduced from the innermost layer to the outermost layer, so that the back mixing among all the stages caused by the back flow of reaction liquid in the annular region of the outer layer is prevented, and the back mixing among all the stages can be reduced to the minimum by a large height difference.
The diameter difference between the inner diameter of the outer layer double-circular flow guide cylinder and the outer diameter of the inner layer double-circular flow guide cylinder between two adjacent layers of double-circular flow guide cylinders in the multilayer double-circular flow guide cylinder bubble reactor is 0.2-2 m. The excessive diameter difference can cause most of reaction liquid overflowing from the inner layer double-circular flow guide cylinder to directly cross the middle layer annular area and enter the outer layer annular area, and the excessive diameter difference can reduce the number of the double-circular flow guide cylinders in the reactor with the same diameter, so that the series number is less and deviates from the plug flow.
Compared with the prior art, the technical scheme of the invention has the beneficial technical effects that:
1) according to the technical scheme, the cyclohexane is oxidized by the multilayer double-loop guide shell bubble reactor, so that the efficiency of the oxidation reaction of the cyclohexane and the selectivity of the oxidation reaction are greatly improved. Multilayer double-circular-flow guide cylinder bubbling reactor is internally provided with a plurality of layers of double-circular-flow guide cylinders, reaction liquid in the multilayer double-circular-flow guide cylinder bubbling reactor is divided into a plurality of annular areas, the annular areas located in the inner area of the innermost double-circular-flow guide cylinder and each annular area are equivalent to a full-mixing kettle, cyclohexane flows through the outermost double-circular-flow guide cylinder from the innermost double-circular-flow guide cylinder step by step, the circulation rate of the reaction liquid is improved, and the whole double-circular-flow guide cylinder bubbling reactor is equivalent to a plurality of full-mixing kettles which are connected in series. Particularly, the double-circulation guide cylinder changes the flow path of reaction liquid by arranging an inner circulation baffle plate and an outer circulation baffle plate, and the reaction liquid forms an inner circulation system in each annular area in the multilayer double-circulation guide cylinder bubbling reactor. In an annular area between two adjacent layers of double circular flow guide cylinders, reaction liquid in the center of the annular area flows upwards under the bubbling effect of oxygen-containing gas, then most of the reaction liquid falls into an outer circular flow area between a guide cylinder main body of an inner layer of double circular flow guide cylinder and a corresponding outer circular flow baffle plate thereof and an inner circular flow area between a guide cylinder main body of an outer layer of double circular flow guide cylinder and a corresponding inner circular flow baffle plate thereof, and flows downwards, bubbles in the inner circular flow area and the outer circular flow area are less, circular flow is formed between the inner circular flow area and liquid rich in bubbles in the center of the annular area due to density difference, and fully mixed flow is formed between two adjacent layers of double circular flow guide cylinders by the reaction liquid; the mixing intensity of the reaction liquid in the annular area is improved, the mass transfer efficiency is greatly improved, and the selectivity of cyclohexyl hydroperoxide, cyclohexanol and cyclohexanone which are intermediate products of cyclohexane oxidation is increased.
2) According to the technical scheme, after the oxidation reaction is finished, cyclohexane separation is directly realized, and cyclohexane can be returned to the oxidation process, so that the evaporation circulation of cyclohexane is avoided, and the energy consumption for distillation is greatly reduced.
3) The technical scheme of the invention maintains the lower conversion rate of cyclohexane in the oxidation process of cyclohexane, when the oxidation conversion rate of cyclohexane is lower, the contents of cyclohexanol and cyclohexanone in oxidation liquid are lower, most of the extracted cyclohexane is remained in cyclohexane phase and returned to the cyclohexane oxidation process for initiating the oxidation reaction of cyclohexane; meanwhile, cyclohexane can be converted into cyclohexyl hydrogen peroxide to the maximum extent, side reactions are effectively prevented, and the selectivity of cyclohexanone and cyclohexanol is greatly improved.
4) According to the technical scheme, a special high-boiling-point organic solvent is introduced in the decomposition process of the cyclohexyl hydroperoxide, and the adopted organic solvent has a high boiling point, is insoluble in water and does not azeotrope with cyclohexanone and cyclohexanol, so that the organic solvent is used for extracting cyclohexanol and cyclohexanone generated by decomposition of the cyclohexyl hydroperoxide to realize separation of the cyclohexanol and the cyclohexanone; on the other hand, the energy consumption is reduced, only the cyclohexanone and the cyclohexanol need to be distilled and separated in the subsequent rectification process, and the residual high-boiling-point organic solvent is directly returned from the kettle bottom for use, so that the energy consumption is greatly reduced compared with the traditional process of firstly distilling and recovering the cyclohexane and then distilling and recovering the cyclohexanone and the cyclohexanol.
5) The decomposition reaction of the invention can adopt a plurality of kettles connected in series, the decomposition reaction can be carried out under a proper temperature sequence, and the decomposition speed of cyclohexyl hydroperoxide in each kettle can be adjusted by adjusting the temperature of each kettle.
6) The invention uses strong base to extract cyclohexyl hydrogen peroxide and adds high boiling point solvent to extract cyclohexanol and cyclohexanone in the decomposition liquid, the extracted cyclohexane phase can directly return to the oxidation reactor after being heated, thereby greatly reducing the energy consumption required by evaporating cyclohexane in the traditional process, improving the cyclohexane oxidation selectivity by 3.0-5.0% compared with the prior art, and reducing the rectification energy consumption by 20-30%.
7) According to the method for preparing cyclohexanol and cyclohexanone, on one hand, the reactor is improved, and the multilayer double-circulation guide shell is arranged in the bubbling reactor, so that the total series number is increased, and the flow of liquid materials is closer to plug flow; on the other hand, oxygen-containing gas with different concentrations is adopted in the cyclohexane oxidation process. The good gas-liquid flow condition of each reaction area is maintained, the sufficient gas-liquid phase interfacial area and the sufficient oxygen partial pressure in the whole reactor are ensured, the mass transfer rate of oxygen is fully matched with the reaction rate, and the oxidation reaction can be stably and efficiently carried out.
8) The invention adopts a multilayer double-circular-flow guide cylinder bubble reactor to oxidize cyclohexane, improves the gas-liquid flowing condition, uses one multilayer double-circular-flow guide cylinder bubble reactor to replace a plurality of reactors connected in series, reduces the equipment quantity, improves the selectivity of the oxidation process, and can improve the cyclohexane oxidation selectivity by 3.0-5.0 percent compared with the prior art.
Drawings
FIG. 1 is a schematic view of a multilayer double-loop guide shell bubble reactor in example 1;
FIG. 2 is a schematic view of a double circular guide shell inside a multilayer double circular guide shell bubbling reactor in example 1; FIG. 3 is a schematic view of a process flow for preparing cyclohexanol and cyclohexanone by oxidation of cyclohexane;
wherein, 1 is a reactor shell, 2 is an outer layer double-circulation guide cylinder, 3 is an inner layer double-circulation guide cylinder, 4 is an annular area, 5 is a liquid inlet, 6 is a gas inlet, 7 is a gas outlet, 8 is a gas distributor, and 9 is a liquid outlet; 20 is a guide cylinder body, 21 is an inner circulation baffle, 22 is an outer circulation baffle, 23 is an inner circulation fixing rib, 24 is an outer circulation fixing rib, 25 is an outer circulation area, 26 is an inner circulation area, and 27 is a supporting base.
Detailed Description
The following examples are intended to illustrate the present disclosure in detail with reference to the accompanying drawings, and not to limit the scope of the claims of the present disclosure.
Example 1
The structure of the multilayer double-circular-flow guide cylinder bubble reactor is shown in figure 1. Multilayer double-circulation draft tube is established to multilayer double-circulation draft tube bubbling reactor's reactor casing 1 endotheca, is two-layer double-circulation draft tube in this embodiment, including the inlayer draft tube 3 that is located the center and the outer dicyclo draft tube 2 that is located the outside, two-layer double-circulation draft tube and reactor casing 1 coaxial arrangement to the diameter is different, separates into tertiary annular region 4 in the reactor casing 1, and the height of double-circulation draft tube reduces to outermost double-circulation draft tube outside step by step along inlayer double-circulation draft tube. A water passing gap 10 is reserved between the bottom of the inner layer double-circular flow guide cylinder 3 and the bottom of the outer layer double-circular flow guide cylinder 2 and the bottom of the reactor shell 1, thus, the three-stage annular areas can flow step by step through the water passing gap 10 between the double-circulation guide cylinder and the bottom of the reactor shell, or can be in cascade overflow series through the top of the double-circulation guide cylinder, the inner layer double-circulation guide cylinder 3 positioned in the center is communicated with the liquid inlet 5, the inner layer double-circulation guide cylinder 3 in each stage of annular area 3 and the center is communicated with the air inlet 6, the liquid inlet 5 and the air inlet 6 are positioned at the bottom of the multilayer double-circulation guide cylinder bubbling reactor, the reactor can be led in and communicated from the top or the bottom of the multilayer double-circular-flow guide cylinder bubble reactor through a pipeline, and gas distributors are respectively arranged at the annular regions 4 in the shell of the reactor and the bottom in the central inner-layer double-circular-flow guide cylinder 3 and are connected with the gas inlets 6 of all layers. The outermost annular region is communicated with a liquid outlet 9, the liquid outlet 9 is fixedly arranged on the side wall of the reactor shell 1, and the top of the reactor shell 1 is provided with a gas outlet 7.
The structure of the double circular guide cylinder is described with reference to fig. 2, taking the outer double circular guide cylinder 2 as an example. The outer layer double-circular flow guide cylinder 2 comprises a guide cylinder main body 20, an inner circular flow baffle plate 21 and an outer circular flow baffle plate 22. The inner wall and the outer wall of the guide cylinder main body 20 are coaxially fixed with a cylindrical inner circulation baffle plate 21 and a cylindrical outer circulation baffle plate 22, the inner circulation baffle plate and the outer circulation baffle plate are respectively fixed on the inner side and the outer side of the guide cylinder main body 20 through an inner circulation fixing rib 23 and an outer circulation fixing rib 24, an inner circulation area 26 and an outer circulation area 25 which flow up and down are respectively formed between the inner circulation baffle plate 21 and the guide cylinder main body 20 and between the outer circulation baffle plate 22 and the guide cylinder main body 20, and the inner circulation baffle plate 21 is coaxially arranged on the inner wall of the reactor shell 1 through the inner circulation fixing rib 23. The top of the inner circulation baffle 21 is a hollow conical structure with a small top and a large bottom, the lower part is a cylindrical straight cylinder, the upper part of the outer circulation baffle 22 arranged outside is a hollow inverted conical structure with a large top and a small bottom, and the lower part is a cylindrical structure.
The bottom edge of the outer double-circulation guide cylinder 2 is provided with a protruding supporting seat 27, and the double-circulation guide cylinder is welded and fixed at the bottom in the reactor shell 1 through the supporting seat 27, so that a water passing gap 10 is formed between the bottom edge of the double-circulation guide cylinder and the bottom of the reactor shell 1. The height of a gap between the bottom edge of the double circulation guide cylinder and the bottom of the shell at the bottom of the reactor is preferably 0.001-0.01 m. The height difference between two adjacent layers of double-circular flow guide cylinders of the multilayer double-circular flow guide cylinders is 0.01-1 meter, and the distance between two adjacent layers of double-circular flow guide cylinders is 0.1-1 meter.
The highest position of the inner annular flow baffle plate 21 is 0.01-1 meter lower than the highest position of the guide cylinder main body 20, the lowest position of the inner annular flow baffle plate 21 is 0.01-1 meter higher than the lowest position of the guide cylinder main body 20, the diameter of the cylindrical structure part of the inner annular flow baffle plate 21 is 0.01-0.4 meter smaller than that of the guide cylinder main body 20, and the diameter of the hollow inverted conical structure part of the inner annular flow baffle plate 21 is 0.04-0.8 meter smaller than that of the guide cylinder main body 20. The highest position of the outer annular flow baffle plate 22 is 0.02-1 meter lower than the highest position of the guide cylinder main body 20, the lowest position of the outer annular flow baffle plate 22 is 0.02-1 meter higher than the lowest position of the guide cylinder main body 20, the diameter of the cylindrical structural part of the outer annular flow baffle plate 22 is 0.01-0.4 meter larger than the diameter of the guide cylinder main body 20, and the diameter of the hollow inverted conical structural part of the outer annular flow baffle plate 22 is 0.04-0.8 meter larger than the diameter of the guide cylinder main body 20.
In practical production application, the size and the number of the double-circulation guide cylinders can be reset according to production requirements, the number of layers of the double-circulation guide cylinders in the multilayer double-circulation guide cylinder bubbling reactor can be set to be 2-9, the height difference of the adjacent double-circulation guide cylinders is 0.01-1 meter, and the diameter difference between the inner diameter of the outer double-circulation guide cylinder and the outer diameter of the inner double-circulation guide cylinder is 0.2-2 meters. In the embodiment, the inner diameter of the shell of the two-layer double-circulation guide cylinder bubbling reactor is 800mm, and the height of the shell is 3000 mm; the inner diameter of a guide cylinder main body of a central inner layer double-circulation guide cylinder is 400mm, the height of the guide cylinder main body is 2600mm, the diameter of a cylindrical structure part of an inner circulation baffle is 350mm, the diameter of the minimum part of a hollow inverted conical structure part is 200mm, the highest part of the inner circulation baffle is 200mm lower than the highest part of the guide cylinder main body, the lowest part of the inner circulation baffle is 30mm higher than the lowest part of the guide cylinder main body, the diameter of the cylindrical structure part of an outer circulation baffle is 440mm, the diameter of the maximum part of the hollow inverted conical structure is 480mm, the highest part of an outer circulation baffle is 400mm lower than the highest part of the guide cylinder main body, and the lowest part of the outer circulation baffle is 40mm higher than the lowest part of the. The inner diameter of a guide cylinder main body of an outer-layer double-circulation guide cylinder is 600mm, the height of the guide cylinder main body is 2400mm, the diameter of a cylindrical structure part of an inner circulation baffle is 560mm, the diameter of a part of a minimum part of a hollow inverted cone-shaped structure is 520mm, the highest position of the inner circulation baffle is 200mm lower than the highest position of the guide cylinder main body, the lowest position of the inner circulation baffle is 25mm higher than the lowest position of the guide cylinder main body, the diameter of a cylindrical structure part of an outer circulation baffle is 640mm, the diameter of the maximum position of a hollow inverted cone-shaped structure is 680mm, the highest position of an outer circulation baffle is 200mm lower than the highest position of the guide cylinder main body, and the lowest position of the outer; the height of the discharge hole on the outermost layer reactor shell is 2200 mm.
A process for oxidizing cyclohexane using the multi-layer, double annular funnel bubble reactor of the example is described below in conjunction with fig. 3.
Introducing cyclohexane into a multilayer double-circular-flow guide cylinder bubbling reactor from a central liquid inlet of the multilayer double-circular-flow guide cylinder bubbling reactor, introducing liquid from the bottom of an inner-layer double-circular-flow guide cylinder 3 through a liquid inlet in the embodiment, sequentially flowing most of the cyclohexane into an annular area between the inner-layer double-circular-flow guide cylinder 3 and an outer-layer double-circular-flow guide cylinder 2 and an annular area between the outer-layer double-circular-flow guide cylinder 2 and a reactor shell 1 from a water gap between the double-circular-flow guide cylinder and the reactor shell, introducing the cyclohexane at a flow speed larger than that of the water gap, after the inner-layer double-circular-flow guide cylinder 3 is filled with the liquid cyclohexane, beginning overflowing a small part of the cyclohexane to the annular area between the inner-layer double-circular-flow guide cylinder 3 and the outer-layer double-circular-flow guide cylinder 2, and enabling a part of the liquid-phase cyclohexane to flow through, and the other part of liquid-phase cyclohexane overflows from the top of the double-circulation guide cylinder layer by layer until the cyclohexane oxidation liquid overflows from the liquid outlet and is discharged. The feeding amount of the cyclohexane is adjusted according to the volume of a reaction zone between a central double-circulation guide cylinder reaction zone and each double-circulation guide cylinder annular zone of each stage of reactor and the residence time of the cyclohexane, so that liquid phase products overflow step by step at a certain speed, and enter the next step after being oxidized in a multi-stage series connection mode.
An inner circulation area and an outer circulation area are additionally arranged inside and outside the double-circulation guide cylinder in the embodiment, part of liquid materials fall into the outer circulation area between the guide cylinder main body of the inner-layer double-circulation guide cylinder and the outer circulation baffle of the inner-layer double-circulation guide cylinder and the inner circulation area between the guide cylinder main body of the outer-layer double-circulation guide cylinder and the inner circulation baffle of the outer-layer double-circulation guide cylinder, the inner circulation area and the outer circulation area are arranged on the periphery of the gas distributor, the liquid materials in the inner circulation area contain few bubbles, the liquid rich in bubbles in the center of the annular area of the double-circulation guide cylinder forms circulation due to density difference, the liquid in the inner circulation area and the liquid in the outer circulation area flow downwards, and the reaction liquid in the central annular area flows upwards, so that the mixing strength of the reaction liquid in the annular area is improved, and the.
Cyclohexane introduced from an inner layer double-circular-flow guide cylinder in the center of the multilayer double-circular-flow guide cylinder bubbling reactor is preheated to 120-200 ℃, the reaction temperature of each annular area in the multilayer double-circular-flow guide cylinder bubbling reactor is kept at 120-200 ℃, and the reaction pressure is kept at 0.4-2 MPa.
In the multilayer double-circulation guide cylinder bubble reactor, the oxygen content of the molecular oxygen-containing gas introduced from the annular area between the inner layer double-circulation guide cylinder at the center and each outer layer double-circulation guide cylinder is 5-70 percent, and the oxygen content is gradually increased along the flowing direction of the cyclohexane oxidation liquid. Specifically, pure oxygen prepared by a cryogenic separation method can be adopted, or oxygen-enriched air with oxygen content of about 70 percent is prepared by a pressure swing adsorption method and then mixed with air to prepare oxygen-enriched air with oxygen content of 21 to 70 percent; pure nitrogen prepared by a cryogenic separation method or oxidation tail gas rich in nitrogen is mixed with air to prepare oxygen-poor air with the oxygen content of 5-21%; the method comprises the steps of enabling a gas distributor connected with a gas inlet pipe communicated with the bottom of an annular area between inner layer double-circular flow guide cylinders in the center and each layer of double-circular flow guide cylinders in a bubbling reactor to enter liquid-phase cyclohexane for oxidation reaction, adjusting reaction temperature, gas inflow and gas inlet oxygen concentration simultaneously, enabling the oxygen content in tail gas in the annular area between the inner layer double-circular flow guide cylinders in the center and each outer layer double-circular flow guide cylinder to be lower than 5%, and recycling the tail gas after processing and recycling cyclohexane.
In the actual oxidation process in this example, oxygen-containing gas was gradually introduced into the multi-layer double-loop draft tube bubble reactor, the aeration rate and oxygen concentration in each reactor were adjusted, the reaction temperature was adjusted to control the oxygen content (dry basis) in the tail gas of each reactor to about 2%, and the cyclohexane residence time was adjusted to about 20 min. After the system operates stably, the reaction temperature is 164-168 ℃, the reaction pressure is 1.2MPa, sampling analysis shows that the liquid phase material with the analysis result tending to be stable contains 1.11% of cyclohexyl hydroperoxide, 0.15% of cyclohexanol and 0.06% of cyclohexanone, the cyclohexane conversion rate is 1.01% by calculation, and the selectivity of useful products (including cyclohexanone, cyclohexanol and cyclohexyl hydroperoxide) is 97.9%.
The above embodiments are illustrative of the present invention and not restrictive, and it should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only illustrative of the specific operating principles of the present invention, and various changes and modifications may be made without departing from the spirit and scope of the present invention, which is defined by the appended claims and their equivalents.
Claims (17)
1. A method for preparing cyclohexanol and cyclohexanone based on a multilayer double-loop flow guide cylinder bubble reactor is characterized by comprising the following steps of: the method comprises the following steps:
1) oxidizing cyclohexane by oxygen-containing gas in a multilayer double-loop guide shell bubble reactor to obtain oxidizing liquid containing cyclohexyl hydroperoxide; wherein, the conversion rate of cyclohexane oxidation is controlled within the range of 0.5 to 1.5 percent; the multilayer double-circular-flow guide cylinder bubbling reactor main body comprises a reactor shell and a multilayer double-circular-flow guide cylinder; the multilayer double-circular-flow guide cylinder comprises a plurality of layers of double-circular-flow guide cylinders which are coaxially sleeved from inside to outside;
the double-circular-flow guide cylinder comprises a guide cylinder main body, an inner circular-flow baffle plate and an outer circular-flow baffle plate; the inner circulation baffle is fixedly arranged on the inner wall of the guide cylinder main body, and the outer circulation baffle is fixedly arranged on the outer wall of the guide cylinder main body; the lower part of the inner annular flow baffle is of a cylindrical structure, and the upper part of the inner annular flow baffle is of a hollow conical structure; the lower part of the outer circulation baffle is of a cylindrical structure, and the upper part of the outer circulation baffle is of a hollow inverted conical structure;
the height from the innermost double circular flow guide cylinder to the outermost double circular flow guide cylinder of the multilayer double circular flow guide cylinders is reduced in a gradient manner, and the inner diameter is increased in a gradient manner;
the multilayer double-circulation guide cylinders are fixedly arranged at the bottom in the reactor shell, and water passing gaps are formed between the bottoms of the double-circulation guide cylinders and the bottom in the reactor shell;
a liquid inlet is formed in the bottom of an area in the innermost double-circular flow guide cylinder of the multilayer double-circular flow guide cylinder;
a liquid outlet is formed in the side wall of the reactor shell, and an air outlet is formed in the top of the reactor shell; an inner annular flow baffle is arranged on the side wall of the reactor shell;
the bottom of an area in the innermost double circular flow guide cylinder, the bottom of an area between every two circular flow guide cylinders and the bottom of an area between the outermost double circular flow guide cylinder and the reactor shell of the multilayer double circular flow guide cylinders are respectively provided with a gas distributor, and each gas distributor is connected with a gas inlet;
the oxygen volume percentage concentration of the oxygen-containing gas is 5-70%, and the oxygen volume percentage concentration of the oxygen-containing gas introduced into each region between the double circulation guide cylinders at the innermost layer and the double circulation guide cylinders at the outermost layer is increased in sequence;
2) extracting and separating the oxidizing solution containing the cyclohexyl hydroperoxide by using strong base solution to obtain an alkaline water phase containing the cyclohexyl hydroperoxide and an organic phase containing cyclohexane; the strong alkali solution is a sodium hydroxide and/or potassium hydroxide solution with the concentration of 0.5-5 mol/L;
3) adding a high-boiling-point organic solvent into the cyclohexyl hydroperoxide containing alkaline water phase, and then carrying out decomposition reaction on the cyclohexyl hydroperoxide to obtain mixed liquid containing cyclohexanol and cyclohexanone;
the high-boiling-point organic solvent is a non-water-soluble organic solvent which has a boiling point of 200-400 ℃ and does not form an azeotrope with cyclohexanol and/or cyclohexanone;
4) settling and separating the mixed solution containing cyclohexanol and cyclohexanone to obtain an organic phase containing cyclohexanol, cyclohexanone and a high-boiling-point organic solvent and a waste alkali solution;
5) and rectifying and separating the organic phase containing cyclohexanol, cyclohexanone and high-boiling-point organic solvent to obtain a mixed product of cyclohexanol and cyclohexanone and the high-boiling-point organic solvent.
2. The method for preparing cyclohexanol and cyclohexanone based on a multilayer double-loop guide cylinder bubble reactor as claimed in claim 1, wherein: the multilayer double-circular-flow guide cylinder comprises 2-9 layers of double-circular-flow guide cylinders which are coaxially sleeved; the height difference between two adjacent layers of double-circular-flow guide cylinders of the multilayer double-circular-flow guide cylinder is 0.01-1 meter, and the distance between two adjacent layers of double-circular-flow guide cylinders is 0.1-1 meter.
3. The method for preparing cyclohexanol and cyclohexanone based on a multilayer double-loop guide cylinder bubble reactor as claimed in claim 1, wherein: the height of the water passing gap is 0.001-0.01 m.
4. The method for preparing cyclohexanol and cyclohexanone based on a multilayer double-loop guide cylinder bubble reactor as claimed in claim 1, wherein: the top of the inner circulation baffle is 0.01-1 m lower than the top of the guide cylinder main body, and the bottom of the inner circulation baffle is 0.01-1 m higher than the bottom of the guide cylinder main body; the diameter of the cylindrical structure of the inner circulating baffle is 0.01-0.4 m smaller than that of the corresponding guide cylinder main body; the diameter of the minimum position of the hollow conical structure of the inner annular flow baffle plate is 0.04-0.8 m smaller than the diameter of the corresponding guide cylinder main body;
the top of the outer circulation baffle is 0.02-1 m lower than the top of the guide cylinder main body, and the bottom of the outer circulation baffle is 0.02-1 m higher than the bottom of the guide cylinder main body; the diameter of the cylindrical structure of the outer circulation baffle plate is 0.01-0.4 m larger than the diameter of the guide cylinder main body; the diameter of the hollow inverted conical structure of the outer circulation baffle plate at the maximum position is 0.04-0.8 m larger than the diameter of the guide cylinder main body.
5. The method for preparing cyclohexanol and cyclohexanone based on a multilayer double-loop guide cylinder bubble reactor as claimed in claim 1, wherein: the lower part of the inner ring flow baffle on the side wall of the reactor shell is of a cylindrical structure, and the upper part of the inner ring flow baffle is of a hollow conical structure; the top of the inner circulation baffle is 0.01-1 meter lower than the top of the side wall of the reactor shell, and the bottom of the inner circulation baffle is 0.01-1 meter higher than the bottom of the side wall of the reactor shell; the diameter of the cylindrical structure of the inner circulating baffle is 0.01-0.4 m smaller than the diameter of the shell of the reactor; the diameter of the minimum position of the hollow conical structure of the inner annular flow baffle is 0.04-0.8 m smaller than that of the corresponding reactor shell.
6. The method for preparing cyclohexanol and cyclohexanone based on a multilayer double-loop guide cylinder bubble reactor according to any one of claims 1 to 5, wherein: introducing cyclohexane into the multilayer double-circulation guide cylinder bubbling reactor from the liquid inlet, and enabling the cyclohexane to flow from the innermost double-circulation guide cylinder to the outermost double-circulation guide cylinder; one part of cyclohexane flows out layer by layer from the inside to the outside from the water passing gap between the bottom of each layer of double-circulation guide cylinder and the inner bottom of the reactor shell, and the other part of cyclohexane overflows layer by layer from the inside to the outside from the top of each layer of double-circulation guide cylinder; between two adjacent layers of double-circular-flow guide cylinders, part of cyclohexane enters an outer circular-flow area between a guide cylinder main body of an inner layer double-circular-flow guide cylinder and a corresponding outer circular-flow baffle plate thereof, part of cyclohexane enters an inner circular-flow area between a guide cylinder main body of an outer layer double-circular-flow guide cylinder and a corresponding inner circular-flow baffle plate thereof, the cyclohexane in the outer circular-flow area and the inner circular-flow area flows downwards, the cyclohexane in a central area between the inner layer double-circular-flow guide cylinder and the outer layer double-circular-flow guide cylinder flows upwards, and the cyclohexane forms full-mixed flow between the two adjacent layers of double-circular-flow guide cylinders; introducing cyclohexane into the multilayer double-circular-flow guide cylinder bubbling reactor, introducing oxygen-containing gas into the multilayer double-circular-flow guide cylinder bubbling reactor from a gas inlet, dispersing by each gas distributor, fully contacting with the cyclohexane to perform oxidation reaction, leading oxidation liquid containing cyclohexyl hydroperoxide obtained by the reaction out of the multilayer double-circular-flow guide cylinder bubbling reactor from a liquid outlet, and leading tail gas after the reaction out of the multilayer double-circular-flow guide cylinder bubbling reactor from a gas outlet.
7. The method for preparing cyclohexanol and cyclohexanone based on a multilayer double-loop guide cylinder bubble reactor of claim 6, wherein: the cyclohexane is preheated to 120-200 ℃ before being introduced into the multilayer double-circular-flow guide cylinder bubbling reactor from the liquid inlet, and the reaction temperature in the multilayer double-circular-flow guide cylinder bubbling reactor is kept at 120-200 ℃ and the pressure is 0.4-2.0 MPa.
8. The method for preparing cyclohexanol and cyclohexanone based on a multilayer double-loop guide cylinder bubble reactor as claimed in claim 1, wherein: 2) in the method, extraction separation is realized by an extraction tower; a packing layer is filled in the middle part in the extraction tower, the strong alkali solution enters the extraction tower from the upper part of the packing layer, and the oxidizing solution containing the cyclohexyl hydroperoxide enters the extraction tower from the lower part of the packing layer; the strong base solution and the oxidation liquid containing the cyclohexyl hydroperoxide are in countercurrent contact in a packing layer, the cyclohexyl hydroperoxide in the oxidation liquid containing the cyclohexyl hydroperoxide is extracted into the strong base solution to form an alkaline aqueous phase containing the cyclohexyl hydroperoxide and is separated from the bottom of the extraction tower, and a raffinate, namely a cyclohexane-containing organic phase, is separated from the top of the extraction tower.
9. The method for preparing cyclohexanol and cyclohexanone based on a multilayer double-loop guide cylinder bubble reactor of claim 8, wherein: the temperature of the strong alkali solution entering the extraction tower is 20-80 ℃, and the temperature of the oxidizing solution containing the cyclohexyl hydroperoxide entering the extraction tower is 20-80 ℃; the mass ratio of the strong alkali solution to the oxidizing solution containing cyclohexyl hydroperoxide is 1: 10-10: 1; the operating pressure of the extraction tower is 0.1-1.0 MPa of absolute pressure.
10. The method for preparing cyclohexanol and cyclohexanone based on a multilayer double-loop guide cylinder bubble reactor as claimed in claim 1, wherein: and (3) adjusting the temperature of the cyclohexane-containing organic phase to 120-200 ℃, and returning to the oxidation step of 1).
11. The method for preparing cyclohexanol and cyclohexanone based on a multilayer double-loop guide cylinder bubble reactor of claim 1, wherein: 3) the decomposition reaction is realized by a decomposition kettle, and the decomposition kettle comprises a first-stage stirring reaction kettle or more than two stages of stirring reaction kettles connected in series; the alkaline aqueous phase containing the cyclohexyl hydroperoxide and the high boiling point organic solvent firstly enter a first-stage stirring reaction kettle for decomposition reaction, if the decomposition reaction is complete, mixed liquid containing cyclohexanol and cyclohexanone is led out from the first-stage stirring reaction kettle, if the decomposition reaction is incomplete, reaction materials in the first-stage stirring reaction kettle are led into a second-stage or more stirring reaction kettle for decomposition reaction until the decomposition reaction is complete, and the mixed liquid containing cyclohexanol and cyclohexanone is led out from the last-stage stirring reaction kettle.
12. The method for preparing cyclohexanol and cyclohexanone based on a multilayer double-loop guide cylinder bubble reactor of claim 11, wherein: the temperature of the alkaline water phase containing the cyclohexyl hydroperoxide entering the first-stage stirring reaction kettle is 20-80 ℃, and the temperature of the high-boiling-point organic solvent entering the first-stage stirring reaction kettle is 60-160 ℃; the weight ratio of the high-boiling-point organic solvent to the cyclohexyl hydroperoxide containing alkaline water phase is 1: 10-10: 1, the temperature of each stirring reaction kettle is maintained at 40-140 ℃, and the operating pressure is 0.1-1.0 MPa absolute pressure.
13. The method for preparing cyclohexanol and cyclohexanone based on a multilayer double-loop guide cylinder bubble reactor as claimed in claim 1, wherein: the settling separation is realized by a settling separator, the mixed liquid containing cyclohexanol and cyclohexanone enters the settling separator from the middle part of the settling separator, standing and settling are carried out in the settling separator, an organic phase containing cyclohexanol, cyclohexanone and high-boiling-point organic solvent is obtained from the top part of the settling separator, and the waste alkali solution is obtained from the bottom part of the settling separator.
14. The process for the preparation of cyclohexanol and cyclohexanone based on a multilayer double-loop fluid guide cylinder bubble reactor according to claim 1 or 13, wherein: and the waste alkali solution contains carboxylate, one part of the waste alkali solution is sent to a waste alkali recovery process, and the other part of the waste alkali solution is supplemented with strong alkali to adjust the concentration to 0.5-5 mol/L and then returns to the extraction separation process of 2).
15. The method for preparing cyclohexanol and cyclohexanone based on a multilayer double-loop guide cylinder bubble reactor as claimed in claim 1, wherein: the rectification separation is realized by a rectification tower, and the operating pressure of the rectification tower is 0.1-10 kPa; obtaining the mixed product of cyclohexanol and cyclohexanone from the top of the rectifying tower, and recovering the high-boiling-point organic solvent from the bottom of the rectifying tower.
16. The method for preparing cyclohexanol and cyclohexanone based on a multilayer double-loop guide cylinder bubble reactor of claim 15, wherein: and adjusting the temperature of the high-boiling-point organic solvent to 60-160 ℃, and returning to the step 3) of the decomposition reaction.
17. The process for the preparation of cyclohexanol and cyclohexanone based on a multilayer double loop chimney bubble reactor of claim 1, 12, 13, 15 or 16, wherein: the high-boiling-point organic solvent is at least one of water-insoluble alkane, naphthenic hydrocarbon or aromatic hydrocarbon, the boiling point of the high-boiling-point organic solvent is 200-400 ℃, and the high-boiling-point organic solvent does not form an azeotrope with cyclohexanol and/or cyclohexanone.
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