Fixed bed ammoximation mixing and reaction system

Abstract

The utility model discloses a fixed bed ammoximation mixing and reaction system, including: fixed bed membrane catalytic reactor, slurry bed reactor, membrane filter and cooler. The utility model discloses fixed bed ammoximation mixing and reaction system simple structure, and the mixing of catalyst fixed and flow makes the contact sufficient, and the operation is stable, and the amount of tertiary butyl alcohol is low, and the energy consumption of tertiary butyl alcohol separation is low, and the utilization rate of hydrogen peroxide is high, and the reaction temperature control is accurate, and the raw material mixing effect is good, and the conversion rate of cyclohexanone is high, and the selectivity of cyclohexanone oxime is high, and no other byproduct is generated, and it is green environmental protection, safe and reliable, and the cost is low, and it is suitable for industrial production.

Description

Technical Field

[0001] This utility model relates to an ammonium oxime mixing and reaction system, specifically a fixed-bed ammonium oxime mixing and reaction system. Background Technology

[0002] Cyclohexanone oxime is an irreplaceable intermediate in the caprolactam industry, with a global annual production exceeding 6 million tons. Currently, over 90% of plants still use the TS-1 / H2O2 / tert-butanol-water system developed by Enichem in Italy. Since cyclohexanone, H2O2, and TS-1 all require homogeneous or pseudo-homogeneous conditions for reaction, traditional processes necessitate the large-scale use of tert-butanol as a co-solvent (tert-butanol / cyclohexanone oxime mass ratio 2:1), resulting in the following technical drawbacks: (1) The energy consumption for tert-butanol recovery is high, with steam consumption as high as 0.9 t / t oxime; (2) High concentrations of tert-butanol will reduce the polarity of the aqueous phase and increase the by-product cyclohexenone oxime; (3) The heat release of the reaction is concentrated, and the hot spots are difficult to eliminate after scale-up; (4) Excessive hydrogen peroxide: To prevent local depletion, n(H2O2) / n(cyclohexanone) is usually >1.1. Excessive H2O2 decomposes under alkaline conditions, which is both wasteful and increases the tail gas treatment load.

[0003] Current technologies still rely on high tert-butanol formulations, and no publicly available systematic solutions for "extremely low tert-butanol" concentrations have been found. To achieve a reduction in tert-butanol concentration, the following technical challenges need to be overcome: (1) How to uniformly dissolve or disperse cyclohexanone in a very low solvent system within milliseconds and achieve uniform addition and dispersion of H2O2; (2) How to remove instantaneous heat release to prevent local temperature rise > 1℃; (3) How to solve the precipitation of the reaction product cyclohexanone oxime in a low solvent system without affecting the operation of membrane filtration; (4) How to monitor and control online to prevent crystallization and oil phase from clogging microchannels and membrane filters.

[0004] CN112426958A discloses an ammonia oximation reaction separation device and method, which is a homogeneous ammonia oximation process using a microchannel mixing reactor and a membrane mixer for mixing reaction. The mixer has drawbacks in catalytic reactions, such as catalyst loss, severe backmixing, low volumetric efficiency, and rapid wear. Furthermore, the microchannel reactor has small channels, making it prone to catalyst blockage, which poses a safety risk.

[0005] In summary, there is an urgent need to find a fixed-bed ammonium oxime mixing and reaction system that is simple in structure, uses a mixture of fixed and mobile catalysts to ensure sufficient contact and stable operation, has low tert-butanol dosage, low energy consumption for tert-butanol separation, high hydrogen peroxide utilization, precise reaction temperature control, good raw material mixing effect, high cyclohexanone conversion rate, high selectivity for cyclohexanone oxime, no other byproducts generated, is green and environmentally friendly, safe and reliable, low in cost, and suitable for industrial production. Utility Model Content

[0006] The technical problem to be solved by this utility model is to overcome the above-mentioned defects of the prior art and provide a fixed-bed ammonium oxime mixing and reaction system with a simple structure, sufficient contact and stable operation due to the mixing of fixed and flowing catalysts, low tert-butanol dosage, low energy consumption for tert-butanol separation, high hydrogen peroxide utilization, precise control of reaction temperature, good raw material mixing effect, high conversion rate of cyclohexanone, high selectivity of cyclohexanone oxime, no other by-products generated, green and environmentally friendly, safe and reliable, low cost, and suitable for industrial production.

[0007] The technical solution adopted by this utility model to solve its technical problem is as follows: A fixed-bed ammonium oxime mixing and reaction system includes: a fixed-bed membrane catalytic reactor, a slurry bed reactor, a membrane filter, and a cooler; the multi-pass discharge port of the fixed-bed membrane catalytic reactor is connected to the inlet at the top of the slurry bed reactor; the discharge port at the bottom of the slurry bed reactor is connected to the inlet of the membrane filter, and the outlet of the membrane filter is connected to the inlet at the top of the slurry bed reactor; the shell-side outlet of the membrane filter is connected to the inlet of the cooler, and the outlet of the cooler is connected to the multi-pass inlet of the fixed-bed membrane catalytic reactor; a hydrogen peroxide inlet is provided in the middle of the outer side of the fixed-bed membrane catalytic reactor.

[0008] The working process of this fixed-bed ammonia oxime mixing and reaction system is as follows: Cyclohexanone and tert-butanol are first dissolved and mixed, and then fed into a fixed-bed membrane catalytic reactor along with ammonia. Simultaneously, hydrogen peroxide is added through the hydrogen peroxide inlet of the fixed-bed membrane catalytic reactor. Under pressure, the hydrogen peroxide permeates through the micropores of the tubular membrane wall, is cut into microdroplets, and enters the inner side of the tubular membrane. There, it reacts with the premixed solution inside the tubular membrane under the catalytic action of the fixed-bed catalyst packed within the membrane. A cooling jacket cools the exothermic pre-reaction. The resulting pre-reaction solution is then fed into a slurry-bed reactor, where the reaction is completed. Subsequently, the oil-water mixture containing the powdered catalyst flows out from the bottom of the slurry bed reactor and is then pumped into a membrane filter via a circulating pump. Under the heating of the heat source in the heating jacket, filtration is performed. The filtrate containing cyclohexanone oxime is filtered out from the shell-side outlet of the membrane filter, part of which is sent to the alcohol recovery tower and part is sent to the cooler. The filtrate containing cyclohexanone oxime is cooled by the cooling jacket and returned to the fixed-bed membrane catalytic reactor. The intercepted powdered catalyst and excess reactants flow out as the separation concentrate from the tube-side outlet of the membrane filter, and the separation concentrate of the oil-water mixture containing the powdered catalyst is sent back to the slurry bed reactor.

[0009] The invention concept of this utility model system is as follows: The fixed-bed membrane catalytic reactor plays the following roles: 1) The catalyst is fixed in the bed and does not flow out with the reactants, so there is no catalyst loss problem and the utilization rate is high; 2) When the reactants pass through the fixed bed, they are forced to pass through the gaps between the catalyst particles, resulting in a long contact time and high mass transfer efficiency; the flow pattern is close to plug flow, the residence time distribution is narrow, and the reaction selectivity is good; it can be used for a long time, the catalyst life is long, and it is suitable for precious metal or expensive catalyst systems; 3) The raw materials undergo partial pre-reaction while being mixed.

[0010] Preferably, the fixed-bed membrane catalytic reactor includes a cylindrical body; multiple tubular membranes are radially bundled and fitted inside the cylindrical body; a first shell side is formed between the outer side of the tubular membranes and the cylindrical body, and a first tube side is formed between the inner side of the tubular membranes; the tubular membranes are filled with a fixed-bed catalyst. By radially bundling multiple tubular membranes inside the cylindrical body, hydrogen peroxide can be rapidly and uniformly dispersed and added at each site. During the mixing process within the tubular membranes, the reaction is immediately initiated. Through the dispersion and uniform replenishment of hydrogen peroxide by multiple tubular membranes, a continuous and uniform reaction of hydrogen peroxide is achieved, thereby ensuring a complete reaction of hydrogen peroxide and avoiding solvent waste or excess.

[0011] Preferably, the gap between adjacent tubular membrane outer walls is 3–50 mm. Since the tubular membrane relies on high-speed turbulent flow for self-cleaning on its inner wall, if the gap is too small, a backflow dead zone will occur, the shell-side fluid will hardly flow, the local solids content will increase, and particles will deposit and backflow, clogging the outer wall of the membrane tube. 3 mm is the lower limit at which a significant dead zone begins to appear. As the gap increases, the mass transfer velocity first increases and then decreases. After >50 mm, the shell-side velocity becomes too low again, and further scaling up provides almost no gain in mass transfer; instead, it unnecessarily increases the shell diameter.

[0012] Preferably, the cylinder and the tubular membrane are sealed at both ends by a hollow flat cylindrical sealing plate.

[0013] Preferably, the diameter of the tubular membrane is 2 to 100 mm (more preferably 10 to 60 mm), and the length is 30 to 5000 mm, the same as the length of the cylinder.

[0014] Preferably, the tubular membrane includes single-channel or multi-channel microporous membranes, etc.

[0015] Preferably, the pore size of the microporous membrane is 10 nm to 100 μm (more preferably 100 nm to 10 μm). At this pore size, good dispersion can be ensured, thereby achieving a good mixing effect.

[0016] Preferably, the microporous membrane comprises one or more of the following: a metal membrane, a ceramic membrane, or an organic membrane. The organic membrane includes polyvinylidene fluoride (PVDF) membranes, polytetrafluoroethylene (PTFE) membranes, nylon membranes, polypropylene membranes, polyethylene membranes, polyethersulfone (PES) membranes, or polysulfone membranes. More preferably, the microporous membrane is a ceramic membrane.

[0017] Preferably, the diameter of the hollow flat cylindrical sealing plate matches that of the cylinder body, the inner bottom surface of the hollow flat cylindrical sealing plate near the tubular membrane seals the tubular membrane and the cylinder body, and an opening is made at the first tube pass of the tubular membrane, and the multi-pass inlet and outlet are located on the outer bottom surface of the hollow flat cylindrical sealing plate away from the tubular membrane.

[0018] Preferably, the cooling jacket of the fixed-bed membrane catalytic reactor has a cold water inlet near the multi-tube pass outlet and a cold water outlet near the multi-tube pass inlet. The purpose of cooling is to prevent the reaction from being violently exothermic, causing the temperature to become too high and thus resulting in side reactions.

[0019] Preferably, the fixed-bed membrane catalytic reactor is equipped with an ultrasonic device.

[0020] Preferably, the slurry bed reactor is equipped with a stirring device.

[0021] Preferably, the cooling jacket of the slurry bed reactor has a cold water inlet on the lower side and a cold water outlet on the upper side. The purpose of cooling is to prevent the reaction from being violently exothermic, causing the temperature to become too high and thus resulting in side reactions.

[0022] Preferably, a circulation pump is provided between the discharge port at the bottom of the slurry bed reactor and the inlet of the membrane filter tube side.

[0023] Preferably, the membrane filter is a tubular filter element with open ends.

[0024] Preferably, the tubular filter element consists of a precision filter layer, a transition layer, and a support layer from the outside to the inside.

[0025] Preferably, the precision filter layer, transition layer, and support layer include ceramic membranes, metal membranes, or organic membranes. The organic membranes include polyvinylidene fluoride membranes, polytetrafluoroethylene membranes, nylon membranes, polypropylene membranes, polyethylene membranes, polyethersulfone membranes, or polysulfone membranes.

[0026] Preferably, the pore sizes of the precision filter layer, transition layer, and support layer gradually increase.

[0027] Preferably, the pore size of the precision filter layer is 0.05 to 10.00 μm (more preferably 0.05 to 5.00 μm).

[0028] Preferably, the thickness of the precision filter layer, when it is a ceramic membrane, is 0.01 to 0.05 mm.

[0029] Preferably, the thickness of the precision filter layer when it is a metal membrane is 0.1 to 0.5 mm.

[0030] Preferably, the pore size of the transition layer is 1 to 10 μm.

[0031] Preferably, the number of layers in the transition layer is 1 to 8.

[0032] Preferably, when the transition layer is a ceramic film, the thickness of each layer is 0.1 to 0.5 mm.

[0033] Preferably, when the transition layer is a metal film, the thickness of each layer is 0.3 to 0.8 mm.

[0034] Preferably, the pore size of the support layer is 10–50 μm.

[0035] Preferably, the thickness of the support layer, whether it is a ceramic film or a metal film, is 0.5 to 1.2 mm.

[0036] Preferably, the heating jacket of the membrane filter has a heat source inlet at the near-tube outlet and a heat source outlet at the near-tube inlet. The purpose of heating is to prevent oxime precipitation due to temperature drop, which could cause membrane filter fouling.

[0037] Preferably, an online cyclohexanone oxime detector is installed after the outlet of the membrane filter tube. Because this invention reduces the amount of tert-butanol, to prevent the precipitation of cyclohexanone oxime within the membrane filter and subsequent clogging, strict temperature control and monitoring of the cyclohexanone oxime concentration are necessary to determine whether the amount of tert-butanol needs to be increased. The online cyclohexanone oxime detector is equipped with an infrared spectrometer and a densitometer, employing a dual detection principle of infrared and densitometric methods.

[0038] Preferably, one or more microchannel mixing reactors connected in series or parallel are provided before the fixed-bed membrane catalytic reactor. By setting up multiple microchannel mixing reactors in series or parallel, better mixing and more complete reaction can be achieved.

[0039] Preferably, the outlet of the cooler is connected to the mixing inlet of the microchannel mixing reactor, and the outlet of the microchannel mixing reactor is connected to the multi-pass inlet of the fixed-bed membrane catalytic reactor.

[0040] In this fixed-bed ammonia oxime mixing and reaction system, the microchannel mixing reactor operates as follows: Cyclohexanone and tert-butanol are first dissolved and mixed, then fed into the mixing inlet of the microchannel mixing reactor along with ammonia. Under preheating by a heat source in the heating jacket, thorough mixing and emulsification are performed. The resulting premixed solution is then fed into a fixed-bed membrane catalytic reactor for pre-reaction. Through the mixing and emulsification of the microchannel mixing reactor and the pre-reaction with hydrogen peroxide, cyclohexanone is uniformly dispersed in the reaction system, preventing cyclohexanone stratification. This allows for normal operation even with a low tert-butanol to cyclohexanone ratio, reducing the concentration of tert-butanol solvent in the reaction product and thus decreasing energy consumption in subsequent solvent evaporation processes.

[0041] Preferably, the microchannel mixing reactor includes passive chaotic microchannels, etc. A microemulsion system of "instantaneous homogeneity-rapid phase separation" can be constructed within the microchannel, thereby ensuring uniform mixing of materials and ultimately forming a heterogeneous microemulsion system. This system can be maintained in the pipeline and reactor for a relatively long time, allowing the reaction to proceed more fully.

[0042] Preferably, the Reynolds number of the passive chaotic microchannel is 100–2500, and the channel diameter is 0.5–5.0 mm. The Reynolds number is limited to prevent the increase of byproducts. When the Reynolds number is too low, laminar flow dominates, resulting in long diffusion distances, low mass and heat transfer efficiency between materials, and an excess of local reactants leading to an increase in side reactions. When the Reynolds number is too high, turbulent pulsations break H2O2 into more micro-clusters, and the instantaneous high concentration on the catalyst surface leads to an increase in side reactions. Furthermore, an excessively high Reynolds number will cause an excessive pressure drop.

[0043] Preferably, the passive chaotic microchannel includes T-shaped, Y-shaped, heart-shaped, serpentine, herringbone, or spiral channels. More preferably, the passive chaotic microchannel is heart-shaped.

[0044] Preferably, the heating jacket of the microchannel mixing reactor has a heat source inlet near the discharge port and a heat source outlet near the mixing inlet. Preheating the microchannel mixing reactor via the heating jacket is more beneficial for the subsequent pre-reaction.

[0045] Preferably, the microchannel mixing reactor is equipped with an ultrasonic device.

[0046] Preferably, one or more membrane mixing reactors are provided in series between the fixed-bed membrane catalytic reactor and the slurry-bed reactor.

[0047] Preferably, the multi-pass discharge port of the fixed-bed membrane catalytic reactor is connected to the second-pass inlet of the membrane mixing reactor, the second-pass discharge port of the membrane mixing reactor is connected to the inlet at the top of the slurry-bed reactor, and the tube-pass outlet of the membrane filter is connected to the second-pass inlet of the membrane mixing reactor; a hydrogen peroxide inlet is provided in the middle of the outer shell of the membrane mixing reactor. By adding the membrane mixing reactor, hydrogen peroxide can be added in stages and uniformly, avoiding ineffective decomposition of hydrogen peroxide due to excessively high local concentrations, reducing the consumption of hydrogen peroxide in the reaction system, and avoiding the excessive oxidation of cyclohexanone and cyclohexanone oxime with hydrogen peroxide to generate byproduct impurities when the local hydrogen peroxide concentration is too high, thereby improving the selectivity of the reaction.

[0048] In this fixed-bed ammonium oxime mixing and reaction system, the membrane mixing reactor operates as follows: the obtained pre-reaction liquid is fed into the second tube inlet of the membrane mixing reactor, and hydrogen peroxide is added through the hydrogen peroxide inlet of the membrane mixing reactor. Under pressure, the hydrogen peroxide is cut into microdroplets through the micropores of the tubular membrane wall and enters the inner side of the tubular membrane, where it undergoes an initial reaction with the pre-reaction liquid inside the tubular membrane. The cooling jacket cools the exothermic reaction, and then the initial reaction liquid is fed into the slurry bed reactor. When the system is running stably, the powdered catalyst is uniformly distributed in the membrane mixing reactor and the slurry bed reactor, enabling efficient mixed catalytic reactions to occur in each part.

[0049] Preferably, the membrane mixing reactor includes a shell; a tubular membrane is sleeved inside the shell; a second shell side is formed between the outer side of the tubular membrane and the shell, and a second tube side is formed inside the tubular membrane; a spiral guide vane is provided in the second tube side; the beginning and end ends of the shell and the tubular membrane are sealed by a tube sheet.

[0050] Preferably, the spiral guide vane includes a segmented and recombinant guide vane, etc.

[0051] Preferably, the segmented and recombinant flow guide includes SV, SK, SX, SH, or SL type flow guides, etc. More preferably, the segmented and recombinant flow guide is an SK type flow guide.

[0052] Preferably, the properties of the tubular membrane in the membrane mixing reactor are the same as those in the fixed-bed membrane catalytic reactor.

[0053] Preferably, the cooling jacket of the membrane mixing reactor has a cold water inlet near the discharge port and a cold water outlet near the feed port. The purpose of cooling is to prevent the reaction from being violently exothermic, causing the temperature to become too high and thus resulting in side reactions.

[0054] Preferably, the membrane mixing reactor is equipped with an ultrasonic device.

[0055] Preferably, a No. 1 filtration device is provided before the fixed-bed membrane catalytic reactor or the microchannel mixing reactor, and a No. 2 filtration device is provided before the fixed-bed membrane catalytic reactor or the membrane mixing reactor.

[0056] Preferably, both the No. 1 and No. 2 filter devices have a feed inlet on one side.

[0057] Preferably, the outlet on the other side of the No. 1 filter device is connected to the multi-pass feed inlet of the fixed-bed membrane catalytic reactor or the mixing feed inlet of the microchannel mixing reactor, and the outlet on the other side of the No. 2 filter device is connected to the hydrogen peroxide feed inlet of the fixed-bed membrane catalytic reactor located in the middle of the outer side of the cylinder or the hydrogen peroxide feed inlet of one or more membrane mixing reactors connected in series.

[0058] Preferably, the layered filter element in the filtration device consists of a support layer, a transition layer, and a precision filter layer, sequentially from the inlet to the outlet.

[0059] Preferably, in the filtration device, the precision filter layer, the transition layer, and the support layer are all ceramic membranes or organic membranes, etc.

[0060] Preferably, the properties of the precision filter layer, transition layer, and support layer in the filtration device are the same as those of the membrane filter.

[0061] Preferably, a flow regulating valve and a flow meter are sequentially installed between the outlet of the No. 2 filter device on the other side and the hydrogen peroxide inlet of the fixed-bed membrane catalytic reactor or membrane mixing reactor.

[0062] Preferably, the heating jacket of the filter device has a heat source inlet near the discharge port and a heat source outlet near the feed port.

[0063] Preferably, the cooling jacket of the cooler has a cold water inlet near the outlet and a cold water outlet near the inlet. The purpose of cooling is to prevent the temperature from rising due to the exothermic reaction. When the temperature exceeds 90°C, the probability of side reactions increases and the selectivity decreases.

[0064] Preferably, all connecting pipelines are equipped with temperature and pressure display instruments.

[0065] The ultrasonic device used in this invention can perform online ultrasonic cleaning, preventing equipment clogging, thereby effectively extending the continuous operation cycle of the equipment and reducing the frequency of shutdown for cleaning.

[0066] This invention utilizes a heating jacket or a cooling jacket to achieve heat exchange, thereby enabling precise control of the reaction temperature.

[0067] The beneficial effects of this utility model are as follows: (1) The fixed-bed ammonium oxime mixing and reaction system of this utility model has a simple structure, is green and environmentally friendly, safe and reliable, and has low cost. It has verified the "double low" target on an industrially feasible scale for the first time, and provides a new path for the green upgrade of traditional caprolactam devices; (2) The combined use of the microchannel mixing reactor, fixed-bed membrane catalytic reactor and membrane mixing reactor involved in the fixed-bed ammonium oxime mixing and reaction system of this utility model solves the problem of the difficulty in mixing heterogeneous raw materials, overcomes the problem of low reaction activity under low solvent system, and solves the problem of easy clogging of membrane filter under heterogeneous product state. Moreover, the combination of fixed and flowing catalyst ensures sufficient contact and stable operation, low tert-butanol dosage, low tert-butanol separation energy consumption, high hydrogen peroxide utilization rate, precise reaction temperature control, good raw material mixing effect, high cyclohexanone conversion rate, high cyclohexanone oxime selectivity, no other by-products generated, low cost, and no scale-up effect. It can be directly coupled with the existing caprolactam device and is suitable for industrial production. Attached Figure Description

[0068] Figure 1 This is a schematic diagram of the overall structure of Example 1 of the fixed-bed ammonium oxime mixing and reaction system of this utility model; Figure 2 This is a schematic diagram of the overall structure of Example 2 of the fixed-bed ammonium oxime mixing and reaction system of this utility model; Figure 3 This is a schematic diagram of the overall structure of Example 3 of the fixed-bed ammonium oxime mixing and reaction system of this utility model; Figure 4 This is a schematic diagram of the fixed-bed membrane catalytic reactor in Examples 1-3 of the fixed-bed ammonium oxime mixing and reaction system of this utility model; Figure 5 yes Figure 4 Schematic diagram of the cross-sectional structure at point AA; Figure 6 This is a top view and a three-dimensional structural schematic diagram of the hollow flat cylindrical sealing plate at the multi-pass feed inlet end of the fixed-bed membrane catalytic reactor in Examples 1 to 3 of the fixed-bed ammonium oxime mixing and reaction system of this utility model; Figure 7 This is a schematic cross-sectional view of the membrane filter in Examples 1-3 of the fixed-bed ammonium oxime mixing and reaction system of this utility model (heating jacket omitted). Figure 8 This is a schematic diagram of the membrane mixing reactor in Examples 2 and 3 of the fixed-bed ammonium oxime mixing and reaction system of this utility model; Figure 9 yes Figure 8 Schematic diagram of the cross-sectional structure at point BB (helical guide vanes omitted). Detailed Implementation

[0069] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0070] Example 1 of a fixed-bed ammonium oxime mixing and reaction system like Figure 1 , 4 As shown in Figure 7, a fixed-bed ammonium oxime mixing and reaction system includes: filtration devices 1# and 2#, a fixed-bed membrane catalytic reactor 3, a slurry-bed reactor 4, a membrane filter 5, and a cooler 14; each of the filtration devices 1# and 2# has a feed inlet 1-1 on one side; the discharge outlet 1-2 on the other side of the filtration device 1# is connected to the multi-pass feed inlet 3-1 of the fixed-bed membrane catalytic reactor 3, and the multi-pass discharge outlet 3-2 of the fixed-bed membrane catalytic reactor 3 is connected to the feed inlet 4-1 at the top of the slurry-bed reactor 4; the filtration device 1#... The discharge port 1-2 on the other side is connected to the hydrogen peroxide inlet 3-3-1 located in the middle of the outer side of the cylinder 3-3 of the fixed bed membrane catalytic reactor 3; the discharge port 4-2 at the bottom of the slurry bed reactor 4 is connected to the tube-side inlet 5-1 of the membrane filter 5, and the tube-side outlet 5-2 of the membrane filter 5 is connected to the inlet 4-1 at the top of the slurry bed reactor 4; the shell-side outlet 5-3 in the middle of the membrane filter 5 is connected to the inlet 14-1 of the cooler 14, and the outlet 14-2 of the cooler 14 is connected to the multi-tube-side inlet 3-1 of the fixed bed membrane catalytic reactor 3.

[0071] In the filter devices 1# and 2#, the layered filter element 6 is composed of a support layer 6-1, a transition layer 6-2, and a precision filter layer 6-3, sequentially from the inlet 1-1 to the outlet 1-2. The precision filter layer 6-3, the transition layer 6-2, and the support layer 6-1 are all ceramic membranes. The precision filter layer 6-3 has a pore size of 0.1μm and a thickness of 0.03mm. The transition layer 6-2 has a pore size of 5.0μm, consists of 3 layers, and each layer has a thickness of 0.3mm. The support layer 6-1 has a pore size of 30μm and a thickness of 1.0mm. The heating jacket 7 of the filter devices 1# and 2# has a heat source inlet 7-1 near the outlet 1-2 and a heat source outlet 7-2 near the inlet 1-1.

[0072] The fixed-bed membrane catalytic reactor 3 includes a cylindrical body 3-3; 14 tubular membranes 8 are radially bundled inside the cylindrical body 3-3; a first shell side 3-3-2 is formed between the outer side of each tubular membrane 8 and the cylindrical body 3-3, and a first tube side 3-4 is formed inside the tubular membrane 8; the tubular membranes 8 are filled with fixed-bed catalyst granular titanium-silicon molecular sieves; the gap between the outer walls of adjacent tubular membranes 8 is 5 mm; the beginning and end ends of the cylindrical body 3-3 and the tubular membranes 8 are sealed by hollow flat cylindrical sealing plates 3-5; the diameter of each tubular membrane 8 is 30 mm, and its length is 250 mm, the same as the length of the cylindrical body 3-3; the tubular membrane 8 is a single-channel ceramic microporous membrane with a pore size of 100 nm; the diameter of the hollow flat cylindrical sealing plate 3-5 matches that of the cylindrical body. The inner bottom surface 3-5-1 of the cavity flat cylindrical sealing plate 3-5 of the near-tubular membrane 8 seals the tubular membrane 8 and the cylinder 3-3, and an opening is made at the first tube pass 3-4 of the tubular membrane 8. The multi-pass feed inlet 3-1 and the discharge outlet 3-2 are located on the outer bottom surface 3-5-2 of the cavity flat cylindrical sealing plate 3-5 away from the tubular membrane 8. The cooling jacket 10 of the fixed bed membrane catalytic reactor 3 has a cold water inlet 10-1 near the multi-pass discharge outlet 3-2 and a cold water outlet 10-2 near the multi-pass feed inlet 3-1. The fixed bed membrane catalytic reactor 3 is equipped with an ultrasonic device. A flow regulating valve 11 and a flow meter 12 are sequentially arranged between the discharge outlet 1-2 on the other side of the No. 2 filter device 1 and the hydrogen peroxide feed inlet 3-3-1 of the fixed bed membrane catalytic reactor 3.

[0073] The slurry bed reactor 4 is equipped with a stirring device 4-3; the cooling jacket 10 of the slurry bed reactor 4 has a cold water inlet 10-1 on the lower side and a cold water outlet 10-2 on the upper side; a circulation pump 13 is provided between the discharge port 4-2 at the bottom of the slurry bed reactor 4 and the tube inlet 5-1 of the membrane filter 5.

[0074] The membrane filter 5 is a tubular filter element 6 with open ends. The tubular filter element 6 consists of a precision filter layer 6-3, a transition layer 6-2, and a support layer 6-1, arranged sequentially from the outside to the inside. All three layers are ceramic membranes. The precision filter layer 6-3 has a pore size of 0.1 μm and a thickness of 0.03 mm. The transition layer 6-2 has a pore size of 5.0 μm, consists of 5 layers, and each layer has a thickness of 0.2 mm. The support layer 6-1 has a pore size of 30 μm and a thickness of 1.0 mm. The heating jacket 7 of the membrane filter 5 has a heat source inlet 7-1 near the tube outlet 5-2 and a heat source outlet 7-2 near the tube inlet 5-1. An online cyclohexanone oxime detector is installed after the tube outlet 5-2 of the membrane filter 5.

[0075] The cooling jacket 10 of the cooler 14 is provided with a cold water inlet 10-1 near the outlet 14-2 and a cold water outlet 10-2 near the inlet 14-1.

[0076] Temperature and pressure display instruments are installed on all connecting pipelines.

[0077] The working process of the fixed-bed ammonia oxime mixing and reaction system in this embodiment of the invention is as follows: Cyclohexanone and tert-butanol are first dissolved and mixed, then fed into filter 1 (1# filter device 1) to filter impurities, and then fed into the fixed-bed membrane catalytic reactor 3. Simultaneously, hydrogen peroxide filtered through filter 1 (2# filter device 1) is added through the hydrogen peroxide inlet 3-3-1 of the fixed-bed membrane catalytic reactor 3. Under pressure, the hydrogen peroxide permeates through the micropores of the tubular membrane 8 and is cut into microdroplets, entering the inner side of the tubular membrane 8. There, it reacts with the premixed liquid inside the tubular membrane 8 under the catalytic action of the fixed-bed catalyst filled within the tubular membrane 8, undergoing a pre-reaction. The cooling jacket 10 cools the exothermic pre-reaction, and the resulting pre-reaction liquid is then fed into… In the slurry bed reactor 4, after the reaction is completed, the oil-water mixture containing the powdered catalyst flows out from the bottom of the slurry bed reactor 4 and is then sent to the membrane filter 5 by the circulation pump 13. Under the heating of hot water in the heating jacket 7, the mixture is filtered. The filtrate containing cyclohexanone oxime is filtered out from the shell-side outlet 5-3 of the membrane filter 5. Part of the filtrate is sent to the alcohol recovery tower and part is sent to the cooler 14. The filtrate containing cyclohexanone oxime is cooled by the cooling jacket 10 and then returned to the fixed-bed membrane catalytic reactor 3. The intercepted powdered catalyst and excess reactants are separated as concentrated liquid and flow out from the tube-side outlet 5-2 of the membrane filter 5. The concentrated liquid of the oil-water mixture containing the powdered catalyst is sent back to the slurry bed reactor 4.

[0078] Example 2 of a fixed-bed ammonium oxime mixing and reaction system like Figure 2 , 4 As shown in Figure 7, based on the system embodiment 1, a microchannel mixing reactor 2 is also provided between the No. 1 filter device 1 and the fixed bed membrane catalytic reactor 3; the outlet 1-2 on the other side of the No. 1 filter device 1 and the outlet 14-2 of the cooler are connected to the mixing inlet 2-1 of the microchannel mixing reactor 2, and the outlet 2-2 of the microchannel mixing reactor 2 is connected to the multi-pass inlet 3-1 of the fixed bed membrane catalytic reactor 3; The microchannel mixing reactor 2 is a heart-shaped passive chaotic microchannel with a Reynolds number of 1600 and a channel diameter of 2.0 mm. The heating jacket 7 of the microchannel mixing reactor 2 has a heat source inlet 7-1 near the discharge port 2-2 and a heat source outlet 7-2 near the mixing inlet 2-1. The microchannel mixing reactor 2 is equipped with an ultrasonic device. The remainder is the same as in Example 1.

[0079] The working process of the fixed-bed ammonia oxime mixing and reaction system in this embodiment differs from that in System Embodiment 1 only in that: cyclohexanone and tert-butanol are first dissolved and mixed, then fed into filter 1 (No. 1 filter device) to filter impurities, and then fed into the mixing inlet 2-1 of the microchannel mixing reactor 2. Under preheating by the heat source in the heating jacket 7, the mixture undergoes thorough mixing and emulsification. The resulting premixed solution is then fed into the fixed-bed membrane catalytic reactor 3 for pre-reaction. The rest is the same as in System Embodiment 1.

[0080] Example 3 of a fixed-bed ammonium oxime mixing and reaction system like Figure 3 , 4 As shown in Figure 9, based on System Embodiment 2, a membrane mixing reactor 9 is further provided between the fixed-bed membrane catalytic reactor 3 and the slurry-bed reactor 4; the multi-pass outlet 3-2 of the fixed-bed membrane catalytic reactor 3 is connected to the inlet 9-1-1 of the second pass 9-1 of the membrane mixing reactor 9, the outlet 1-2 on the other side of the No. 2 filter device 1 is connected to the hydrogen peroxide inlet 9-2-1 located in the middle of the outer side of the shell 9-2 of the membrane mixing reactor 9, the outlet 9-1-2 of the second pass 9-1 of the membrane mixing reactor 9 is connected to the inlet 4-1 at the top of the slurry-bed reactor 4, and the outlet 5-2 of the membrane filter 5 is connected to the inlet 9-1-1 of the second pass 9-1 of the membrane mixing reactor 9; The membrane mixing reactor 9 includes a shell 9-2; a tubular membrane 8 is fitted inside the shell 9-2; a second shell side 9-3 is formed between the outer side of the tubular membrane 8 and the shell 9-2, and a second tube side 9-1 is formed inside the tubular membrane 8; SK-type spiral guide vanes 9-1-3 are provided inside the second tube side 9-1; the beginning and end ends of the shell 9-2 and the tubular membrane 8 are sealed by a tube sheet 9-4; the tubular membrane 8 has a diameter of 30 mm and a length of 250 mm, and is longer than the shell 9-2. The same degree; the tubular membrane 8 is a single-channel ceramic microporous membrane with a pore size of 100nm; the cooling jacket 10 of the membrane mixing reactor 9 has a cold water inlet 10-1 near the discharge port 9-1-2 and a cold water outlet 10-2 near the feed port 9-1-1; the membrane mixing reactor 9 is equipped with an ultrasonic device; a flow regulating valve 11 and a flow meter 12 are sequentially installed between the discharge port 1-2 on the other side of the #2 filter device 1 and the hydrogen peroxide feed port 9-2-1 of the membrane mixing reactor 9. The rest is the same as in system embodiment 2.

[0081] The difference between the working process of the fixed-bed ammonium oxime mixing and reaction system in this embodiment and System Embodiment 2 lies only in the following: the obtained pre-reaction liquid is fed into the feed port 9-1-1 of the second tube side of the membrane mixing reactor 9. Hydrogen peroxide filtered by the No. 2 filter device 1 is added through the hydrogen peroxide feed port 9-2-1 of the membrane mixing reactor 9. Under pressure, the hydrogen peroxide is cut into microdroplets through the micropore channels of the tubular membrane 8 and enters the inner side of the tubular membrane 8, where it undergoes an initial reaction with the pre-reaction liquid. The cooling jacket 10 cools the exothermic reaction, and then the initial reaction liquid is fed into the slurry bed reactor 4. When the system is running stably, the powdered catalyst is uniformly distributed in the membrane mixing reactor 9 and the slurry bed reactor 4, enabling efficient mixed catalytic reactions to occur in each part. The rest is the same as System Embodiment 2.

Claims

1. A fixed-bed ammonium oxime mixing and reaction system, characterized in that, include: Fixed-bed membrane catalytic reactors, slurry-bed reactors, membrane filters, and coolers; The multi-tube discharge port of the fixed-bed membrane catalytic reactor is connected to the feed port at the top of the slurry-bed reactor; the discharge port at the bottom of the slurry-bed reactor is connected to the tube inlet of the membrane filter, and the tube outlet of the membrane filter is connected to the feed port at the top of the slurry-bed reactor; the shell outlet in the middle of the membrane filter is connected to the inlet of the cooler, and the outlet of the cooler is connected to the multi-tube feed port of the fixed-bed membrane catalytic reactor; a hydrogen peroxide feed port is provided in the middle of the outer side of the shell of the fixed-bed membrane catalytic reactor.

2. The fixed-bed ammonium oxime mixing and reaction system according to claim 1, characterized in that: The fixed-bed membrane catalytic reactor includes a cylindrical body; multiple tubular membranes are radially bundled within the cylindrical body; a first shell side is formed between the outer side of each tubular membrane and the cylindrical body, and a first tube side is formed between the inner side of each tubular membrane; the tubular membranes are filled with a fixed-bed catalyst; the gap between the outer walls of adjacent tubular membranes is 3–50 mm; the beginning and end of the cylindrical body and the tubular membranes are sealed by hollow flat cylindrical sealing plates; the diameter of each tubular membrane is 2–100 mm, and its length is 30–5000 mm, the same as the length of the cylindrical body; the tubular membranes include single-channel or multi-channel microporous membranes; the pore size of each microporous membrane is 10 nm–100 μm; the microporous membranes include metal membranes. The membrane is a composite membrane consisting of one or more of the following: ceramic membranes or organic membranes; the diameter of the hollow flat cylindrical sealing plate matches the cylinder body; the inner bottom surface of the hollow flat cylindrical sealing plate near the tubular membrane seals the tubular membrane and the cylinder body, and an opening is made at the first tube pass of the tubular membrane; the multi-tube pass inlet and outlet are located on the outer bottom surface of the hollow flat cylindrical sealing plate away from the tubular membrane; the cooling jacket of the fixed-bed membrane catalytic reactor has a cold water inlet near the multi-tube pass outlet and a cold water outlet near the multi-tube pass inlet; the fixed-bed membrane catalytic reactor is equipped with an ultrasonic device; the slurry bed reactor is equipped with a stirring device; the cooling jacket of the slurry bed reactor has a cold water inlet on one side at the bottom. A cold water outlet is provided on one side of the upper part; a circulation pump is provided between the discharge port at the bottom of the slurry bed reactor and the inlet of the membrane filter tube side; the membrane filter is a tubular filter element with open ends; the tubular filter element consists of a precision filtration layer, a transition layer, and a support layer from the outside to the inside; the precision filtration layer, transition layer, and support layer include ceramic membranes, metal membranes, or organic membranes; the pore size of the precision filtration layer, transition layer, and support layer gradually increases; the pore size of the precision filtration layer is 0.05–10.00 μm; the thickness of the precision filtration layer when it is a ceramic membrane is 0.01–0.05 mm; the thickness of the precision filtration layer when it is a metal membrane is... The thickness of the membrane is 0.1–0.5 mm; the pore size of the transition layer is 1–10 μm; the number of transition layers is 1–8; when the transition layer is a ceramic membrane, the thickness of each layer is 0.1–0.5 mm; when the transition layer is a metal membrane, the thickness of each layer is 0.3–0.8 mm; the pore size of the support layer is 10–50 μm; the thickness of the support layer, whether ceramic or metal, is 0.5–1.2 mm; the heating jacket of the membrane filter has a heat source inlet near the tube outlet and a heat source outlet near the tube inlet; an online cyclohexanone oxime detector is installed after the tube outlet of the membrane filter.

3. The fixed-bed ammonium oxime mixing and reaction system according to claim 1 or 2, characterized in that: Alternatively, one or more microchannel mixing reactors connected in series or parallel may be provided before the fixed-bed membrane catalytic reactor; the outlet of the cooler is connected to the mixing inlet of the microchannel mixing reactor, and the outlet of the microchannel mixing reactor is connected to the multi-pass inlet of the fixed-bed membrane catalytic reactor; the microchannel mixing reactor includes passive chaotic microchannels; the Reynolds number of the passive chaotic microchannels is 100–2500, and the channel diameter is 0.5–5.0 mm; the passive chaotic microchannels include T-shaped, Y-shaped, heart-shaped, serpentine, herringbone, or spiral channels; the heating jacket of the microchannel mixing reactor has a heat source inlet near the outlet and a heat source outlet near the mixing inlet; the microchannel mixing reactor is equipped with an ultrasonic device; Alternatively, one or more membrane mixing reactors may be connected in series between the fixed-bed membrane catalytic reactor and the slurry-bed reactor; the multi-pass discharge port of the fixed-bed membrane catalytic reactor is connected to the second-pass feed port of the membrane mixing reactor, the second-pass discharge port of the membrane mixing reactor is connected to the top feed port of the slurry-bed reactor, and the tube-pass outlet of the membrane filter is connected to the second-pass feed port of the membrane mixing reactor; a hydrogen peroxide feed port is provided in the middle of the outer side of the membrane mixing reactor shell; the membrane mixing reactor includes a shell; a tubular membrane is sleeved inside the shell; the tubular membrane... A second shell-side is formed between the outer side of the membrane and the tubular shell, and a second tubular side is formed between the inner side of the tubular membrane; a spiral guide vane is provided in the second tubular side; the beginning and end of the tubular shell and the tubular membrane are sealed by a tube sheet; the spiral guide vane includes segmented and recombined type guide vanes; the segmented and recombined type guide vanes include SV, SK, SX, SH, or SL type guide vanes; the relevant properties of the tubular membrane in the membrane mixing reactor are the same as those in the fixed-bed membrane catalytic reactor; the cooling jacket of the membrane mixing reactor has a cold water inlet near the discharge port and a cold water outlet near the feed port; an ultrasonic device is provided on the membrane mixing reactor; Alternatively, a No. 1 filtration device may be provided before the fixed-bed membrane catalytic reactor or the microchannel mixing reactor, and a No. 2 filtration device may be provided before the fixed-bed membrane catalytic reactor or the membrane mixing reactor. Both No. 1 and No. 2 filtration devices have inlets on one side. The outlet of the No. 1 filtration device is connected to the multi-pass inlet of the fixed-bed membrane catalytic reactor or the mixing inlet of the microchannel mixing reactor. The outlet of the No. 2 filtration device is connected to the hydrogen peroxide inlet of the fixed-bed membrane catalytic reactor located in the middle of the outer side of the reactor body, or to the hydrogen peroxide inlet of one or more membrane mixing reactors connected in series. The feed inlet is connected; the layered filter element in the filtration device consists of a support layer, a transition layer, and a precision filter layer sequentially from the feed inlet to the discharge outlet; in the filtration device, the precision filter layer, transition layer, and support layer are all ceramic membranes or organic membranes; the relevant properties of the precision filter layer, transition layer, and support layer in the filtration device are the same as those of the membrane filter; a flow regulating valve and a flow meter are sequentially installed between the discharge outlet on the other side of the No. 2 filtration device and the hydrogen peroxide feed inlet of the fixed-bed membrane catalytic reactor or membrane mixing reactor; the heating jacket of the filtration device has a heat source inlet near the discharge outlet and a heat source outlet near the feed inlet; The cooling jacket of the cooler has a cold water inlet near the outlet and a cold water outlet near the inlet; Temperature and pressure display instruments are installed on all connecting pipelines.

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