Benzene selective hydrogenation reactor and benzene selective hydrogenation reaction method

Abstract

The invention discloses a benzene selective hydrogenation reactor and a benzene selective hydrogenation reaction method.The reactor comprises a reaction kettle, a feeding pipeline, a stirring device, a heat preservation jacket, a speed reducing plate, a slurry backflow pipeline, a product outlet and an exhaust pipeline, the speed reducing plate is arranged in the reaction kettle and divides the reaction kettle into a lower reaction area and an upper settlement area, and the stirring device is arranged in the reaction kettle; the speed reducing plate is provided with a speed reducing channel, and the lower reaction area and the upper settlement area are communicated through the speed reducing channel; the stirring device is provided with a stirring element, and the stirring element is arranged in the lower reaction zone; the slurry backflow pipeline is arranged outside the reaction kettle, one end of the slurry backflow pipeline is connected with a liquid outlet of the upper settlement area, and the other end of the slurry backflow pipeline is connected with a liquid return opening of the lower reaction area; the product outlet is formed in the upper settlement area and is higher than the liquid outlet; the exhaust pipeline is arranged at the upper part of the reaction kettle. The benzene selective hydrogenation reactor and the benzene selective hydrogenation reaction method provided by the invention have improved cyclohexene selectivity.

Description

Technical Field

[0001] The invention belongs to the technical field of petrochemical industry, and in particular relates to a benzene selective hydrogenation reactor and a benzene selective hydrogenation reaction method. Background Art

[0002] Cyclohexene is an important organic chemical raw material, which is widely used in the fields of pharmaceutical and fine chemical synthesis. Its most important application is the production of synthetic fibers. Cyclohexene can be directly hydrated to produce cyclohexanol, directly oxidized to produce adipic acid, or dehydrogenated to produce cyclohexanone, and then produce caprolactam through a series of reactions. Compared with the traditional route of selective hydrogenation of benzene to produce a mixture of cyclohexanol and cyclohexanone by catalytic oxidation of cyclohexane, the cyclohexene route shortens the production route of nylon-66 and caprolactam, has a high single-pass conversion rate, less by-products, and is more energy-saving and environmentally friendly. Currently, the selective hydrogenation of benzene to produce cyclohexene has huge industrial production potential.

[0003] In 1988, Asahi Chemical Corporation of Japan built the world's first benzene selective cyclohexene device. In the late 1990s, my country had made great progress in the research of benzene selective hydrogenation catalysts and industrial devices, such as CN1176886C, CN 1597098A, CN 1714932A, CN 1696087A, CN 105056943A, CN 101850225A, CN102600841A, CN 102744085A and CN 105126839A.

[0004] The hydrogenation reaction of benzene is a gas-liquid reaction, which is carried out in an autoclave reactor. In the existing Ru-based catalyst system, it is usually necessary to add a ZnSO4 aqueous solution to ensure the high selectivity of cyclohexene. The subsequent separation of the aqueous phase slurry containing zinc sulfate and the catalyst and the oil phase product cyclohexene is involved. The currently reported benzene selective hydrogenation devices, such as CN 1696087A and CN101850225A, etc., are all completed by adding a settler or a separation tank. The selectivity of cyclohexene is one of the important indicators of performance evaluation. In traditional reactors, due to the complicated separation process, the aqueous phase slurry and the oil phase product are prone to reverse mixing again, so that cyclohexene contacts the catalyst in the aqueous phase slurry again to generate cyclohexane by hydrogenation reaction, resulting in a reduction in the selectivity of cyclohexene. In addition, the additional addition of the tank body is bound to increase the cost and complicate the operation process. Therefore, if the separation process can be simplified, the selectivity of cyclohexene can be further improved, and the equipment cost and maintenance difficulty can be reduced, it will be a great progress in the industrialized selective hydrogenation reaction of benzene, and it will have a broad application prospect. Summary of the invention

[0005] In order to solve the above problems in the prior art, the present invention provides a novel benzene selective hydrogenation reactor and a benzene selective hydrogenation reaction method, which can realize reaction-separation integration.

[0006] In a first aspect, the present invention provides a benzene selective hydrogenation reactor, the reactor comprising: a reactor, a feed pipeline, a stirring device, a heat-insulating jacket, a deceleration plate, a slurry reflux pipeline, a product outlet and an exhaust pipeline, wherein:

[0007] The deceleration plate is arranged in the reactor and divides the reactor into a lower reaction zone and an upper settling zone. The deceleration plate is provided with a deceleration channel, in particular, a deceleration channel with a pore size decreasing from bottom to top. The lower reaction zone and the upper settling zone are connected via the deceleration channel.

[0008] One end of the feed pipe is located outside the reactor, and the other end extends into the lower reaction zone;

[0009] The stirring device is provided with a stirring element, and the stirring element is arranged in the lower reaction zone;

[0010] The heat-insulating jacket is arranged outside the reactor and surrounds at least a portion of the reactor;

[0011] The slurry reflux pipeline is arranged outside the reactor, one end of which is connected to the liquid outlet of the upper sedimentation zone, and the other end of which is connected to the liquid return port of the lower reaction zone;

[0012] The product outlet is arranged in the upper settling zone and is higher than the liquid outlet;

[0013] The exhaust pipe is arranged on the upper part of the reactor.

[0014] According to the benzene selective hydrogenation reactor provided by the present invention, the reactor can be any reactor known in the art. Generally, the reactor comprises a reactor body and a matching sealing cover.

[0015] According to the benzene selective hydrogenation reactor provided by the present invention, the feed pipeline includes a gas feed pipeline and a benzene feed pipeline.

[0016] In the present invention, one end of the gas inlet pipe and the benzene inlet pipe extends into the bottom of the lower reaction zone and opens downward or toward the stirring element, thereby facilitating uniform mixing of materials.

[0017] In the present invention, the gas inlet pipeline and the benzene inlet pipeline are respectively provided with a flow meter and a flow regulating valve for regulating the flow of gas and benzene.

[0018] According to the benzene selective hydrogenation reactor provided by the present invention, the deceleration plate is provided with a plurality of deceleration channels, and the density of the deceleration channels gradually becomes sparse from the center to the edge. By such an arrangement, when the slurry (or liquid) vortex is generated by stirring in the lower reaction zone, the speed of the slurry (or liquid) is fast at the edge and relatively lagging in the middle, thereby ensuring that after the slurry passes through the deceleration plate, the rising speed (flux) of the overall liquid level can be consistent and the liquid level rises steadily.

[0019] In some embodiments, the spacing of the outermost deceleration channels of the deceleration plate is 1.5-10 times the spacing of the central deceleration channels, such as 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10 or any value therebetween, preferably 1.5-5 times.

[0020] According to the benzene selective hydrogenation reactor provided by the present invention, the diameter of the deceleration channel in the deceleration plate is 0.1 cm-30 cm, preferably 0.1 cm-10 cm.

[0021] According to the benzene selective hydrogenation reactor provided by the present invention, the aperture of the deceleration channel of the deceleration plate on the lower surface is 2-50 times the aperture of the upper surface, for example, 2, 3, 4, 5, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50 or any value therebetween, preferably 2-20 times.

[0022] According to the benzene selective hydrogenation reactor provided by the present invention, the deceleration plate comprises a plurality of layers of deceleration plate elements, each layer of the deceleration plate elements is provided with a plurality of through holes, and the through holes of the plurality of layers of the deceleration plate elements are connected to form the deceleration channel.

[0023] According to the benzene selective hydrogenation reactor provided by the present invention, the materials of the deceleration plate and the deceleration plate element are independently stainless steel mesh, porous ceramic material or film.

[0024] According to the benzene selective hydrogenation reactor provided by the present invention, a plurality of limit screws for installing the speed reducer are provided on the side wall of the reactor, so that the speed reducer can be installed at different heights. Furthermore, the water-oil interface can be regulated by changing the placement position of the speed reducer, so that the static liquid level is higher than the speed reducer.

[0025] In some embodiments, the speed brake is installed at 1 / 2 to 2 / 3 of the height.

[0026] According to the benzene selective hydrogenation reactor provided by the present invention, the slurry reflux pipeline comprises a main reflux pipeline and an auxiliary reflux pipeline arranged in parallel, and the auxiliary reflux pipeline is provided with a pump and a switch valve. The main reflux pipeline can naturally reflux by relying on the potential energy difference, and the auxiliary reflux pipeline can control the reflux speed by means of a pump and a switch valve.

[0027] According to the benzene selective hydrogenation reactor provided by the present invention, the stirring element is arranged at the lower side of the lower reaction zone, preferably aligned horizontally with the liquid return port. In the present invention, the stirring element can be blade-shaped or rod-shaped, and its rotation can ensure sufficient contact between the reaction raw materials and the catalyst in the reaction system.

[0028] In some embodiments, the stirring device is a mechanical stirrer, one end of a stirring rod of which is mounted on the sealing cover, the stirring rod extends through the speed reduction plate, and the other end of the stirring rod is provided with a blade-shaped or rod-shaped stirring element.

[0029] According to the benzene selective hydrogenation reactor provided by the present invention, a pressure gauge and a pressure regulating valve are arranged on the exhaust pipe.

[0030] According to the benzene selective hydrogenation reactor provided by the present invention, a heat exchange medium is passed through the heat-insulating jacket. The present invention has no special requirements for the heat exchange medium, and any heat exchange medium known in the art can be used.

[0031] In a second aspect, the present invention provides a method for selective hydrogenation of benzene, characterized in that the method is carried out by the benzene selective hydrogenation reactor of the present invention.

[0032] The method for selective hydrogenation of benzene provided by the present invention comprises the following steps:

[0033] 1) preparing a reaction slurry comprising a catalyst, water and zinc sulfate and adding the slurry to the benzene selective hydrogenation reactor;

[0034] 2) introducing an inert gas such as nitrogen to replace the air in the benzene selective hydrogenation reactor, and adding benzene;

[0035] 3) heating the benzene selective hydrogenation reactor to 100-200° C., preferably 130-160° C., introducing hydrogen to carry out the reaction, preferably, controlling the hydrogen pressure to 4-5 MPa;

[0036] 4) Obtain the target product from the product outlet.

[0037] According to the benzene selective hydrogenation reaction method provided by the present invention, the average flow rate of benzene is 30-60 kg / h, preferably 30-40 kg / h; and / or the circulation rate of the reaction slurry is 60-160 kg / h, preferably 60-70 kg / h.

[0038] According to the benzene selective hydrogenation reaction method provided by the present invention, the reaction in step 3) is carried out at a rotation speed of 200-600 r / min, preferably 300-500 r / min.

[0039] According to the method for selective hydrogenation of benzene provided by the present invention, the catalyst is selected from metal-modified ZrO2 catalyst, SiO2 catalyst and Al2O3-based catalyst, and / or the mass ratio of the catalyst, water and zinc sulfate is 1:(50-500):(0-80). For example, the mass ratio of the catalyst to water can be 1:50, 1:60, 1:70, 1:80, 1:90, 1:100, 1:120, 1:140, 1:160, 1:200, 1:240, 1:280, 1:300, 1:350, 1:400, 1:500 or any value therebetween. For example, the mass ratio of the catalyst to zinc sulfate can be 1:5, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, 1:60, 1:70, 1:80, or any value therebetween. In some embodiments, the mass ratio of the catalyst, water and zinc sulfate is 1:(50-500):(10-80).

[0040] According to the benzene selective hydrogenation reaction method provided by the present invention, wherein the reaction slurry also includes an additive, and the additive is selected from one or more combinations of 1,3-propylene glycol, polyethylene glycol, ethylene glycol, ethanolamine, diethanolamine, diphenylamine, ethylenediamine and diethylamine. In the present invention, the number average molecular weight of the suitable polyethylene glycol can be 700-6000g / mol. In some embodiments, the additive includes 1,3-propylene glycol, ethylene glycol and monoethanolamine in a mass ratio of (1.5-2.5): (4-6): 1.

[0041] When used, the amount of the additive accounts for 0.01%-10% of the water quality. For example, the amount of the additive can account for 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 5%, 6%, 7%, 8%, 9%, 10% or any value therebetween of the water quality. In some embodiments, the amount of the additive can account for 0.01%-4% of the water quality.

[0042] The above raw materials in the present invention can be prepared in-house or commercially available, and the present invention is not particularly limited thereto.

[0043] The present invention has the following advantages:

[0044] 1) For the existing reactor, the separation of slurry and product requires an additional settler or separation tank, while the benzene selective hydrogenation reactor of the present invention, by providing a deceleration plate and other matching structures, enables the separation function to be completed at the upper part of the reactor at the same time;

[0045] 2) The slurry reflux pipeline can make full use of the potential energy difference, so that the energy consumption required for the slurry reflux process is greatly reduced;

[0046] 3) The benzene selective hydrogenation reactor of the present invention exhibits higher cyclohexene selectivity than the conventional reaction unit;

[0047] 4) The benzene selective hydrogenation reactor of the present invention can reduce the number of reactors, and no additional settler or separation tank is required. The simplified process flow greatly reduces the investment cost and simplifies the operation steps of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a schematic structural diagram of an embodiment of a benzene selective hydrogenation reactor according to the present invention;

[0049] Figure 2 is a bottom view of a deceleration plate in a benzene selective hydrogenation reactor according to the present invention;

[0050] Among them, 1-gas inlet pipeline, 2-benzene inlet pipeline, 3-sealing cover, 4-stirring device, 5-insulating jacket, 6-speed reducer, 7-slurry reflux pipeline, 8-product outlet, and 9-exhaust pipeline. DETAILED DESCRIPTION

[0051] The present invention will be further described below in conjunction with specific embodiments, but they do not constitute any limitation to the present invention.

[0052] The present invention provides a benzene selective hydrogenation reactor.

[0053] Reference Figure 1 The benzene selective hydrogenation reactor of the present invention comprises a reaction kettle, a feed pipeline, a stirring device 4, a heat-insulating jacket 5, a deceleration plate 6, a slurry reflux pipeline 7, a product outlet 8 and an exhaust pipeline 9.

[0054] The reactor is a Hastelloy high-pressure reactor, comprising a reactor body and a matching sealing cover 3.

[0055] The deceleration plate 6 is arranged in the reactor and divides the reactor into a lower reaction zone and an upper settling zone. The deceleration plate 6 is provided with a deceleration channel with a diameter decreasing from bottom to top, and the lower reaction zone and the upper settling zone are connected via the deceleration channel.

[0056] The density of the deceleration channel gradually becomes sparse from the center to the edge. With this arrangement, when the slurry (or liquid) vortex is generated by stirring in the lower reaction zone, the speed of the slurry (or liquid) is fast at the edge and relatively lagging in the middle. This ensures that after the slurry passes through the deceleration plate, the rising speed (flux) of the overall liquid level can be consistent and the liquid level rises smoothly. The spacing of the outermost deceleration channels of the deceleration plate 6 can be 1.2-5 times the spacing of the central deceleration channels, such as 1.2, 1.5, 2, 3, 4, 5 or any value therebetween. Figure 2 In the illustrated embodiment, the spacing between the outermost two rows of deceleration channels is three times the average spacing between the center two rows of deceleration channels.

[0057] The diameter of the deceleration channel of the deceleration plate 6 is 0.1cm-30cm, preferably 0.1cm-10cm. The deceleration plate 6 includes a plurality of layers of deceleration plate elements, each layer of the deceleration plate elements is provided with a plurality of through holes, and the through holes of the plurality of layers of the deceleration plate elements are connected to form a deceleration channel. When the deceleration plate 6 is composed of a plurality of layers of deceleration plate elements, the deceleration channels from the lower layer to the upper layer are the first channel, the second channel, the third channel, and so on, and the aperture of the channel gradually decreases, so that when the liquid (slurry) passes through the first channel, it will be separated into a plurality of water flows by the first channels, and then flow to the second channel. Since the aperture of the second channel is smaller than the aperture of the first channel, part of the water flow is blocked, and the other part of the water flow passes through the second channel, and then flows to the third channel in the same way, and so on, reducing the flow rate of the liquid flowing through the deceleration plate 6 in the same time; the aperture of the deceleration channel gradually decreases from bottom to top, so that when the bottom liquid passes upward, its flow rate gradually decreases until it stops, and the liquid above the deceleration plate 6 realizes the stratification of the product and the reaction slurry.

[0058] The materials of the deceleration plate 6 and the deceleration plate element are independently stainless steel mesh, porous ceramic material or film. A plurality of limit screws for installing the deceleration plate are provided on the side wall of the reactor to install the deceleration plate at different heights. The deceleration plate 6 is installed at a height of 1 / 2 to 2 / 3. Furthermore, the water-oil interface can be adjusted by changing the placement position of the deceleration plate 6, so that the static liquid level is higher than the deceleration plate 6.

[0059] The stirring device 4 is provided with a stirring element, which is arranged in the lower reaction zone. The stirring element can be blade-shaped or rod-shaped, and its rotation can ensure that the reaction raw materials and the catalyst in the reaction system are fully contacted.

[0060] One end of the feed pipeline is located outside the reactor, and the other end extends into the lower reaction zone. Specifically, the feed pipeline includes a gas inlet pipeline 1 and a benzene inlet pipeline 2. One end of the gas inlet pipeline 1 and the benzene inlet pipeline 2 extends into the bottom of the lower reaction zone and opens downward or toward the stirring element. A flow meter and a flow regulating valve are respectively provided on the gas inlet pipeline 1 and the benzene inlet pipeline 2 to regulate the flow of gas and benzene.

[0061] The heat-insulating jacket 5 is arranged outside the reactor and surrounds the reactor; a heat-exchange medium, including water, steam or heat-conducting oil, etc., can pass through the heat-insulating jacket 5 and can be adjusted according to the reaction conditions.

[0062] The slurry reflux pipeline 7 is arranged on the outside of the reactor, one end of which is connected to the liquid outlet of the upper sedimentation zone, and the other end is connected to the liquid return port of the lower reaction zone. The liquid outlet is located above the deceleration plate 6, and is lower than the liquid level of the static liquid above the deceleration plate 6. The slurry reflux pipeline includes a main reflux pipeline and an auxiliary reflux pipeline arranged in parallel. The main reflux pipeline can be provided with a flow meter and a flow regulating valve, and the auxiliary reflux pipeline is provided with a pump and a switch valve. The main reflux pipeline can naturally reflux by relying on the potential energy difference, and its flow rate can be controlled by the flow regulating valve, while the auxiliary reflux pipeline can control the reflux speed by a pump and a switch valve. In particular, if a larger flow rate is required, the switch valve can be opened to allow the slurry to reflux to the lower reaction zone through the auxiliary reflux pipeline.

[0063] The product outlet 8 is arranged in the upper settling zone and is higher than the liquid outlet.

[0064] The exhaust pipe 9 is arranged on the upper part of the reactor, and can be arranged on the sealing cover 3 in particular, on which a pressure gauge and a pressure regulating valve are arranged, and the pressure in the reactor can be adjusted by regulating the gas discharge.

[0065] The working principle of the device of the present invention is as follows:

[0066] After adding the reaction slurry prepared with catalyst, water and zinc sulfate into the benzene selective hydrogenation reactor, the sealing cover 3 is sealed; a certain amount of nitrogen is introduced through the gas inlet pipe 1 to replace the air in the reactor, and then a certain amount of benzene is introduced through the benzene inlet pipe 2, the stirring device 4 is turned on and a certain speed is set, and at the same time, the temperature is increased through the insulation jacket 5; after the temperature is stabilized, a certain amount of hydrogen is introduced through the gas inlet pipe 1, and the pressure is kept stable by controlling the flow rate, and the reaction is carried out for a certain time; the rotation of the blades of the stirring device 4 will cause obvious flow of the liquid at the bottom of the reactor; the reactor is equipped with a deceleration plate 6, and after the slurry in the lower reaction zone passes through the deceleration plate 6 upward, its flow rate gradually decreases until it stops, and stratification is achieved in the upper sedimentation zone, the upper layer is a mixed liquid of oil phase cyclohexene and benzene, which is extracted from the product outlet 8, and the lower layer is the reaction slurry, which flows back to the lower reaction zone from the slurry reflux pipe 7. Temperature control can be achieved by controlling the medium parameters of the insulation jacket 5; gas discharge can be controlled by adjusting the pressure regulating valve on the exhaust pipe 9 to achieve pressure control in the reactor; the liquid level and oil-water interface in the reactor can be controlled by adjusting the position of the deceleration plate 6.

[0067] Example 1

[0068] The reactor is heated to 140°C by the heat exchange medium (water vapor) in the insulation jacket 5, and the reaction pressure is set to 5.0 MPa and the rotation speed is 300 r / min; the deceleration plate 6 uses 5 layers of stainless steel mesh with mesh numbers of 20, 50, 100, 150 and 200 from bottom to top, and is placed at 2 / 3 of the height of the reactor.

[0069] The specific operation process is as follows: after adding the reaction slurry prepared by Ru-Zn / ZrO2 catalyst, water and zinc sulfate (mass ratio 1:140:25) into the reactor, seal the sealing cover 3, introduce nitrogen through the gas inlet pipe 1 to replace the air in the reactor, and then introduce benzene through the benzene inlet pipe 2, the average benzene flow rate is 55.4kg / h, the slurry circulation volume is 153.6kg / h, turn on the stirring device 4, set the speed to 300r / min, and heat the reactor to 140°C through the insulation jacket 5; after the temperature stabilizes, introduce hydrogen through the gas inlet pipe 1, and control the flow rate to keep the pressure stable at 5.0MPa.

[0070] In this embodiment, an obvious stratification is formed in the upper settling zone. After the reaction, the product flows out from the product outlet 8. It is measured that when the benzene conversion rate is 50.6%, the cyclohexene selectivity is 74.6%.

[0071] Example 2

[0072] In this embodiment, the speed reducer 6 uses 5 layers of stainless steel mesh, and the mesh sizes from bottom to top are 100 mesh, 120 mesh, 200 mesh, 240 mesh and 300 mesh, the average benzene flow rate is 54.5 kg / h, and other conditions are the same as those in Example 1.

[0073] In this embodiment, an obvious stratification is formed in the upper settling zone, and when the benzene conversion rate is 51.3%, the cyclohexene selectivity is 66.5%.

[0074] Comparative Example 1

[0075] In Comparative Example 1, the multi-layer stainless steel mesh speed reducer 6 was not placed, and the average benzene flow rate was 53.6 kg / h, and other conditions were the same as those in Example 1. After 30 minutes of reaction, when the benzene conversion rate was 50.0%, the cyclohexene selectivity was 60.2%.

[0076] Example 3

[0077] The reactor is heated to 150°C by the heat exchange medium (heat transfer oil) in the insulation jacket 5, and the reaction pressure is set to 4.5MPa and the rotation speed is 400r / min; the speed reducer 6 is made of porous ceramic material with an average pore diameter of 2cm. The pores of the porous ceramic material are evenly distributed and the thickness is 10cm. It is placed at 1 / 2 the height of the reactor.

[0078] The specific operation process is as follows: after adding the reaction slurry prepared by Ru-Zn / Al2O3 catalyst, water and zinc sulfate (mass ratio 1:100:20) into the reactor, seal the sealing cover 3, introduce a certain amount of nitrogen through the gas inlet pipe 1 to replace the air in the reactor, and then introduce benzene through the benzene inlet pipe 2, the average benzene flow rate is 34.1kg / h, and the slurry circulation volume is 68.4kg / h; turn on the stirring device 4, set the speed to 400r / min, and heat the reactor to 140°C through the insulation jacket 5; after the temperature stabilizes, introduce hydrogen through the gas inlet pipe 1, and control the flow rate to keep the pressure stable at 4.5MPa.

[0079] In this embodiment, an obvious stratification is formed in the upper settling zone. After the reaction, the product flows out from the product outlet 8. It is measured that when the benzene conversion rate is 50.1%, the cyclohexene selectivity is 79.7%.

[0080] Comparative Example 2

[0081] In Comparative Example 2, the porous ceramic speed reducer 6 was not placed, the average benzene flow rate was 35.4 kg / h, and other conditions were the same as those in Example 3. After 30 minutes of reaction, when the benzene conversion rate was 50.4%, the cyclohexene selectivity was 66.5%.

[0082] Comparative Example 3

[0083] Comparative Example 3 A porous ceramic speed reducer 6 was placed, with an average pore size of 15 cm, an average benzene flow rate of 33.9 kg / h, and other conditions were the same as those of Example 3. No obvious oil-water separation interface appeared during the experiment.

[0084] Example 4

[0085] In this embodiment, the speed reducer 6 is made of porous ceramic material, the spacing between the two outermost rows of mesh holes is 3 times the average spacing between the two central rows of mesh holes, the thickness is 10 cm, and other conditions are the same as those in Embodiment 1.

[0086] Obvious stratification was formed in the upper settling zone. After the reaction, the product flowed out from the product outlet 8. It was measured that when the benzene conversion rate was 50.2%, the cyclohexene selectivity was 80.6%.

[0087] Example 5

[0088] The reactor is heated to 140°C by the heat exchange medium (water vapor) in the insulation jacket 5, and the reaction pressure is set to 5.0 MPa and the rotation speed is 300 r / min; the deceleration plate 6 uses 5 layers of stainless steel mesh with mesh numbers of 20, 50, 100, 150 and 200 from bottom to top, and is placed at 2 / 3 of the height of the reactor.

[0089] The specific operation process is as follows: Ru-Zn / ZrO2 catalyst, water, zinc sulfate, and additive mixture (the mass ratio of 1,3-propylene glycol, ethylene glycol, and monoethanolamine is 2:5:1) are configured to obtain a reaction slurry, wherein the mass ratio of Ru-Zn / ZrO2 catalyst, zinc sulfate, water, and additive mixture is 1:30:200:7. After the prepared reaction slurry is added to the reactor, the sealing cover 3 is sealed, nitrogen is introduced through the gas inlet pipe 1 to replace the air in the reactor, and then benzene is introduced through the benzene inlet pipe 2, with an average benzene flow rate of 54.2kg / h and a slurry circulation volume of 151.4kg / h. The stirring device 4 is turned on, the speed is set to 300r / min, and the reactor is heated to 140°C through the insulation jacket 5; after the temperature stabilizes, hydrogen is introduced through the gas inlet pipe 1, and the pressure is kept stable at 5.0MPa by controlling the flow rate.

[0090] In this embodiment, an obvious stratification is formed in the upper settling zone. After the reaction, the product flows out from the product outlet 8. It is measured that when the benzene conversion rate is 53.6%, the cyclohexene selectivity is 79.4%.

[0091] Example 6

[0092] In this embodiment, a mixture of diethylamine and diethanolamine of equal mass (mass ratio of 2:5) is used to replace the additive mixture in Example 5, and other conditions and reaction parameter settings are the same as those in Example 5.

[0093] In this embodiment, an obvious stratification is formed in the upper settling zone, and when the benzene conversion rate is 52.3%, the cyclohexene selectivity is 78.6%.

[0094] By comparing Examples 1-2 and Comparative Example 1, as well as Example 3 and Comparative Example 2, it can be concluded that the reactor of the present invention can achieve higher cyclohexene selectivity than the reactor without a speed reducer. Without wishing to be limited by theory, it is believed that the reactor of the present invention further improves the separation efficiency of the oil phase product and the water phase slurry, reduces back mixing, and inhibits cyclohexene from contacting the catalyst in the water phase slurry again to undergo deep hydrogenation reaction to generate cyclohexane, so the selectivity of cyclohexene is higher.

[0095] Further, by comparing Example 1 with Example 2 and Example 1 with Example 4, it can be found that the pore size, porosity and pore distribution of the speed reducer affect the selectivity of the product cyclohexene. By comparing Example 3 with Comparative Example 3, it can be concluded that the change of the speed reducer parameters will achieve different speed reduction effects, thereby affecting the formation of the oil-water separation interface. Examples 5 and 6 show that the addition of organic additives in the test method has a good effect.

[0096] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A benzene selective hydrogenation reactor, characterized in that: The reactor comprises: a reaction kettle, a feed pipeline, a stirring device (4), a heat-insulating jacket (5), a deceleration plate (6), a slurry reflux pipeline (7), a product outlet (8) and an exhaust pipeline (9), wherein: The deceleration plate (6) is arranged in the reactor and divides the reactor into a lower reaction zone and an upper sedimentation zone. The deceleration plate (6) is provided with a deceleration channel, in particular, a deceleration channel with a pore size decreasing from bottom to top. The lower reaction zone and the upper sedimentation zone are connected via the deceleration channel. One end of the feed pipe is located outside the reactor, and the other end extends into the lower reaction zone; The stirring device (4) is provided with a stirring element, and the stirring element is arranged in the lower reaction zone; The heat-insulating jacket (5) is arranged outside the reactor and surrounds at least a portion of the reactor; The slurry reflux pipeline (7) is arranged outside the reactor, one end of which is connected to the liquid outlet of the upper sedimentation zone, and the other end of which is connected to the liquid return port of the lower reaction zone; The product outlet (8) is arranged in the upper settling zone and is higher than the liquid outlet; The exhaust pipe (9) is arranged on the upper part of the reactor.

2. The benzene selective hydrogenation reactor according to claim 1, characterized in that: The feed pipeline comprises a gas feed pipeline (1) and a benzene feed pipeline (2); Preferably, one end of the gas inlet pipeline (1) and the benzene inlet pipeline (2) extends into the bottom of the lower reaction zone and opens downward or toward the stirring element; and / or, a flow meter and a flow regulating valve are respectively provided on the gas inlet pipeline (1) and the benzene inlet pipeline (2).

3. The benzene selective hydrogenation reactor according to claim 1 or 2, characterized in that: The deceleration plate (6) is provided with a plurality of deceleration channels, and the density of the deceleration channels gradually becomes sparser from the center to the edge; And / or, the diameter of the deceleration channel in the deceleration plate (6) is 0.1 cm-30 cm, preferably 0.1 cm-10 cm.

4. The benzene selective hydrogenation reactor according to any one of claims 1 to 3, characterized in that: The deceleration plate (6) comprises a plurality of deceleration plate elements, each layer of the deceleration plate elements is provided with a plurality of through holes, and the through holes of the plurality of layers of the deceleration plate elements are connected to form the deceleration channel; And / or, the deceleration plate (6) is made of a stainless steel mesh, a porous ceramic material or a film; And / or, the inner wall of the reactor is provided with a plurality of limit screw groups in the vertical direction for installing the deceleration plate (6), so as to install the deceleration plate (6) at different heights.

5. The benzene selective hydrogenation reactor according to any one of claims 1 to 4, characterized in that: The slurry return pipeline (7) comprises a main return pipeline and an auxiliary return pipeline which are arranged in parallel, and the auxiliary return pipeline is provided with a pump and a switch valve; and / or, the stirring element is disposed at the lower side of the lower reaction zone and horizontally aligned with the liquid return port; And / or, the exhaust pipe (9) is provided with a pressure gauge and a pressure regulating valve; And / or, a heat exchange medium passes through the thermal insulation jacket (5).

6. A method for selective hydrogenation of benzene, characterized in that: The method is carried out by the benzene selective hydrogenation reactor according to any one of claims 1 to 5, and preferably comprises the following steps: 1) preparing a reaction slurry comprising a catalyst, water and zinc sulfate and adding the slurry to the benzene selective hydrogenation reactor; 2) introducing an inert gas such as nitrogen to replace the air in the benzene selective hydrogenation reactor, and adding benzene; 3) heating the benzene selective hydrogenation reactor to 100-200° C., preferably 130-160° C., introducing hydrogen to carry out the reaction, preferably, controlling the hydrogen pressure to 4-5 MPa; 4) Obtain the target product from the product outlet.

7. The method for selective hydrogenation of benzene according to claim 6, characterized in that: The average flow rate of benzene is 30-60 kg / h, preferably 30-40 kg / h; and / or the circulation rate of the reaction slurry is 60-160 kg / h, preferably 60-70 kg / h.

8. The method for selective hydrogenation of benzene according to claim 6 or 7, characterized in that: The reaction in step 3) is carried out at a rotation speed of 200-600 r / min, preferably 300-500 r / min.

9. The method for selective hydrogenation of benzene according to any one of claims 6 to 8, characterized in that: The catalyst is selected from metal-modified ZrO2 catalyst, SiO2 catalyst and Al2O3-based catalyst, and / or the mass ratio of the catalyst, water and zinc sulfate is 1:(50-500):(0-80).

10. The method for selective hydrogenation of benzene according to any one of claims 6 to 9, characterized in that: The reaction slurry further comprises an additive, wherein the additive is selected from one or a combination of 1,3-propylene glycol, polyethylene glycol, ethylene glycol, ethanolamine, diethanolamine, diphenylamine, ethylenediamine and diethylamine; Preferably, the amount of the additive is 0.01%-10% of the water mass, preferably 0.01%-4%.

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