WO2021047043A1 - System and process for preparing propylene oxide based on micro-interface enhanced propylene epoxidation - Google Patents

Abstract

A system and a process for preparing propylene oxide based on micro-interface enhanced propylene epoxidation, comprising: a reactor, a micro-interface generator, and a reflux pipe. By means of breaking propylene gas to form micron-scale micron-sized bubbles and mixing the micron-sized bubbles with feed liquid to form a gas-liquid emulsion, the area of the phase boundary between the gas and liquid phases is increased, and the effect of enhancing mass transfer within a lower preset operating condition range is achieved; in addition, the micron-sized bubbles can fully mix with the feed liquid to form a gas-liquid emulsion, and fully mixing the gas and liquid phases can ensure that the oxygen source solution in the system can come into full contact with the propylene gas, thereby preventing the generation of by-products, and further increasing the reaction efficiency of the system.

Description

System and process for preparing propylene oxide based on micro-interface enhanced propylene epoxidation Technical field

The invention relates to the technical field of propylene epoxidation, in particular to a system and process for preparing propylene oxide based on micro-interface enhanced propylene epoxidation.

Background technique

Propylene oxide (PO) is an important basic chemical raw material. It ranks among the world's 50 largest chemicals in production, and is the third largest organic chemical product in propylene derivatives after polypropylene and acrylonitrile in production. PO has a very strong oxygen-containing three-membered ring, which has very active chemical properties and a wide range of uses. It is mainly used to produce polyether, propylene glycol, isopropanolamine, allyl alcohol, non-polyether polyols, etc., and then produce unsaturated Polyester resins, polyurethanes, surfactants (oil field demulsifiers, pesticide emulsifiers and wetting agents), etc., are widely used in chemical, light industry, medicine, food, textile and other industries, and have a profound effect on the development of the chemical industry and the national economy. Impact. With the expansion of the use of PO and the continuous increase in the amount of downstream products, especially the prosperity of the automobile, construction and home furnishing industries, the demand for polyurethane and non-ionic surfactants has increased significantly, resulting in a strong market demand for PO.

All domestic PO production adopts the chlorohydrin method. The production has serious corrosion pollution, high cost, low conversion rate, poor selectivity, and the demand is increasing year by year. With the increasing environmental protection requirements, the existing technology is also facing huge survival challenges, so we are looking for An environmentally friendly green production process to produce PO is imminent. With hydrogen peroxide as the oxidant, the titanium silicon molecular sieve can catalyze the propylene epoxidation reaction to synthesize PO with a high conversion rate and selectivity, opening up a new way for the synthesis of PO. The process is simple, the product conversion rate is high, the selectivity is good, and it does not pollute the environment. It is a highly competitive propylene oxide production process. It meets the requirements of contemporary green chemistry and the development of atomic economy. It is considered to be the green production of PO. New Technology.

Chinese Patent Publication Number: CN207632812U discloses a method for epoxidation of propylene by using a homogeneous or water/oil two-phase reaction medium with an oxygen source and an oxygen source under the conditions of 20℃～80℃ and 0.5～1.5MPa. Propylene reacts for 3-8 hours under the catalysis of TS-2 molecular sieve-containing composite catalyst solution to produce products, wherein the molar ratio of propylene to oxygen source is 0.5-20, and the molar ratio of propylene to catalyst solution is 1-10. This problem is better solved, and it can be used in industrial production of propylene epoxidation. It can be seen that the method has the following problems:

First, in the method, the materials are mixed only by stirring, and propylene forms large bubbles after stirring. However, the volume of the bubbles is too large to be fully mixed with the materials, which reduces the reaction efficiency of the system.

Second, in the case of uneven contact between the material and propylene, the method will cause methanol and methanol to react to form dimethyl ether. The system also needs to perform subsequent processing on the generated dimethyl ether, which increases the system's Energy consumption.

Summary of the invention

To this end, the present invention provides a system and process for preparing propylene oxide based on micro-interface enhanced propylene epoxidation to overcome the problem of low system reaction efficiency caused by uneven mixing of materials and by-products in the prior art.

In one aspect, the present invention provides a system for preparing propylene oxide based on micro-interface enhanced propylene epoxidation, which includes:

The reactor is used to provide a reaction place for the propylene gas and the oxygen source solution, and the reactor includes: set below, to load the propylene gas, the oxygen source solution and the catalyst solution, and to provide a reaction space for the propylene gas and the oxygen source solution. Mixed flow reaction zone and plug flow reaction zone set up above to transport materials and separate gas and liquid after the reaction is completed;

The micro-interface generator, which is set at a designated position in the fully mixed flow reaction zone, converts the pressure energy of the gas and/or the kinetic energy of the liquid into the surface energy of the bubble and transmits it to the propylene gas, so that the propylene gas is broken to form a diameter ≥ 1 μm, And <1mm micron-level bubbles to increase the mass transfer area between the oxygen source solution and propylene gas, reduce the thickness of the liquid film, reduce the mass transfer resistance, and mix the oxygen source solution with the micron-level bubbles to form a gas-liquid emulsion after being broken , To enhance the mass transfer efficiency and reaction efficiency between the oxygen source solution and the propylene gas within the preset operating conditions;

A reflux pipe, which is set on the side wall of the reactor, is used to preheat the material output from the reactor and return it to the reactor after preheating so that the oxygen source solution in the material can fully react and the temperature of the material in the reactor Make adjustments.

Further, the micro-interface generator includes:

The first micro-interface generator is a pneumatic micro-interface generator. The first micro-interface generator is arranged in the fully mixed flow reaction zone and located at the bottom of the reaction zone, and is used to break the propylene gas into micron-sized micrometers. After the crushing is completed, the micron-level bubbles are output to the reactor and mixed with the oxygen source solution in the reactor to form a gas-liquid emulsion;

A second micro-interface generator, which is a hydraulic or gas-liquid linkage type micro-interface generator, the second micro-interface generator is arranged in the fully mixed flow reaction zone to receive the material output by the return pipe, The material is used to entrain the unreacted propylene gas in the plug flow reaction zone and the propylene gas is broken to form micron-sized micro-sized bubbles, the micro-sized bubbles are mixed with the material to form a gas-liquid emulsion, and the gas-liquid emulsion is output to the whole The mixed-flow biochemical reaction zone is opposed to the gas-liquid emulsion output by the first micro-interface generator, so as to extend the residence time of micron-sized bubbles in the mixed-flow biochemical reaction zone and cause the propylene gas to undergo a secondary reaction.

Further, the fully mixed flow reaction zone includes:

The first feed pipe is arranged on the side wall of the reactor and is connected to the first micro-interface generator, and is used to deliver propylene gas to the first micro-interface generator so that the first micro-interface generator reacts to propylene. Gas is broken;

An oxygen source feed port, which is arranged on the side wall of the reactor and above the first feed pipe, and is used to deliver the oxygen source solution to the inside of the reactor;

A catalyst feed port, which is arranged on the side wall of the reactor and above the oxygen source feed port, and is used to transport the catalyst solution to the inside of the reactor;

The residue outlet, which is arranged at the bottom of the reactor, is used to discharge the residue generated during the reaction of the materials in the reactor.

Further, the plug flow reaction zone includes:

The second feed pipe is arranged in the reactor, and the bottom end of the second feed pipe is connected with the second micro-interface generator, and the top end of the second feed pipe is located above the liquid level in the reactor, Used to entrain the unreacted propylene gas at the top of the reactor to the second micro-interface generator so that the second micro-interface generator breaks the propylene gas;

A discharging port, which is arranged on the side wall of the reactor to output the material containing propylene oxide out of the reactor;

A reflux outlet, which is arranged on the side wall of the reactor, and is used to output the reaction-completed mixture containing propylene oxide to the reflux pipe;

The reflux feed pipe is arranged on the side wall of the reactor and the two ends of the reflux feed pipe are respectively connected with the second micro-interface generator and the reflux pipe to output the preheated mixture in the reflux pipe to the second Two micro-interface generators;

The tail gas outlet, which is arranged at the top of the reactor, is used to discharge the tail gas generated after the reaction of the materials in the reactor.

Further, the return pipe includes:

A circulating pump, which is connected to the reactor, and is used to output the reaction-completed mixture in the reactor;

The heat exchanger is connected with the circulation pump and is used to exchange heat for the mixture output by the circulation pump to maintain the mixture within a preset temperature range.

Further, the outlet of the heat exchanger is connected to the second micro-interface generator for outputting the preheated mixture to the second micro-interface generator.

On the other hand, the present invention provides a process for preparing propylene oxide based on the enhanced propylene epoxidation of micro-interface, including:

Step 1: Feed the oxygen source solution into the reactor through the oxygen source feed port, and feed the catalyst solution into the reactor through the catalyst feed port;

Step 2: Transport propylene gas into the reactor through the first feed pipe, the first feed pipe will transport the propylene gas to the first micro-interface generator, and the first micro-interface generator breaks the propylene gas , Forming micron-scale micron-scale bubbles, after the crushing is completed, the first micro-interface generator outputs the micron-scale bubbles into the reactor and mixes with the oxygen source solution in the fully mixed flow reaction zone to form a gas-liquid emulsion;

Step 3: The gas-liquid emulsion reacts under the action of the catalyst solution to generate a mixture containing propylene oxide. After the reaction is completed, the mixture flows upward into the plug flow reaction zone;

Step 4: After the mixture enters the plug flow reaction zone, it enters the reflux pipe through the reflux outlet, and the heat exchanger will heat the mixture in the pipeline to a specified temperature,

Step 5: After preheating, the mixture enters the second micro-interface generator through the reflux feed pipe. The second micro-interface generator uses the high pressure generated by the sprayed mixture to entrain the unreacted propylene gas at the top of the reactor to In the second micro-interface generator, the propylene gas is broken into micro-sized micro-sized bubbles;

Step 6: The second micro-interface generator mixes the micron-sized bubbles with the mixture to form a gas-liquid emulsion after the crushing is completed, and outputs the gas-liquid emulsion to the fully mixed flow biochemical reaction zone to fully react in the gas-liquid emulsion;

Step 7: After the reaction is completed, propylene oxide flows upward to the plug flow reaction zone. In the plug flow reaction zone, a small amount of tail gas contained in the propylene oxide moves upward and is discharged through the tail gas outlet. The oxypropane is output from the reactor through the discharge port.

Further, the residue remaining after the reaction of the gas-liquid emulsion in the step 3 will settle to the bottom of the reactor and be discharged from the reactor through the residue outlet.

Further, in the process, the reaction temperature in the reactor is 20-70° C., and the reaction pressure is 0.1-0.8 MPa.

Further, the gas-liquid ratio in the first micro-interface generator is 1000-1500:1, and the gas-liquid ratio in the second micro-interface generator is 400-600:1.

Compared with the prior art, the beneficial effect of the present invention is that the present invention breaks the propylene gas to form micron-sized micro-sized bubbles, and mixes the micro-sized bubbles with the raw material liquid to form a gas-liquid emulsion, so as to increase the gas-liquid two-phase The phase boundary area of this invention can achieve the effect of enhancing mass transfer within the lower preset operating conditions; at the same time, the system reactor of the present invention is equipped with a reflux feed pipe, by returning the reacted materials to the reactor, After the reaction, the propylene gas in the material reacts again, which prolongs the contact time between the propylene gas and the material, thereby increasing the conversion rate of the propylene gas. In addition, the range of preset operating conditions can be flexibly adjusted according to different product requirements or different catalysts, which further ensures the full and effective progress of the reaction, thereby ensuring the reaction rate, and achieving the purpose of strengthening the reaction.

In addition, the range of preset operating conditions can be flexibly adjusted according to different product requirements or different catalysts, which further ensures the full and effective progress of the reaction, thereby ensuring the reaction rate, and achieving the purpose of strengthening the reaction.

In particular, the present invention provides a fully mixed flow reaction zone in the reactor. By arranging the micro-interface generator in the fully mixed flow reaction zone, the inside of the fully mixed flow reaction zone is closer to the full mixed flow model, which ensures the temperature and concentration of the materials in the reaction zone. It is uniform, and when the materials enter the reaction zone, they can be quickly mixed uniformly, thereby preventing part of the oxygen source solution and propylene gas from mixing unevenly in the reaction zone to generate by-products, and further improving the reaction efficiency of the system.

In particular, the present invention also provides a plug flow reaction zone in the reactor. By setting the plug flow reaction zone, the material can move at a uniform speed in a specified direction, effectively preventing the material from producing backflow during the conveying process, and the plug flow reaction zone can further The reaction rate of the materials in the full mixed flow biochemical reaction zone is promoted, thereby further improving the reaction efficiency of the system.

Further, the reactor of the present invention is provided with a pneumatic micro-interface generator and a gas-liquid linkage micro-interface generator. By using different types of micro-interface generators, the micro-level bubbles and materials are mixed more uniformly, thereby improving the reactor The mixing efficiency of the inner material and the micron-level bubbles can further improve the reaction efficiency of the system.

Further, the system is also provided with a reflux pipe, which can fully use the unreacted raw material liquid in the materials by refluxing the reacted materials, thereby improving the utilization rate of the materials, thereby further improving the reaction efficiency of the system.

In particular, the reflux pipe is provided with a heat exchanger, and when the reacted material is refluxed, the heat exchange can be performed on the material through the heat exchanger to maintain the material within a preset temperature range, so as to improve the temperature in the reactor. The temperature of the material is adjusted to further improve the reaction efficiency of the system.

Further, the top of the reactor is provided with a tail gas outlet. After the reaction of the materials in the reactor is completed, the tail gas in the materials will be suspended to the top of the reactor and discharged from the reactor through the tail gas outlet, which reduces the reaction energy consumption of the reactor.

Further, the bottom of the reactor is provided with a residue outlet. When the reaction of the materials in the reactor is completed, the solid residue in the materials will settle to the bottom of the reactor and be discharged from the reactor through the residue outlet, further reducing the reactor Reaction energy consumption.

Description of the drawings

Fig. 1 is a schematic structural diagram of the system for preparing propylene oxide based on the micro-interface enhanced propylene epoxidation according to the present invention.

detailed description

The preferred embodiments of the present invention will be described below with reference to the drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention, and are not intended to limit the protection scope of the present invention.

It should be noted that in the description of the present invention, the terms "upper", "lower", "left", "right", "inner", "outer" and other terms indicating directions or positional relationships are based on the attached drawings. The direction or position relationship shown is only for ease of description, and does not indicate or imply that the device or element must have a specific orientation, be configured and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

In addition, it should be noted that, in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, they can be fixed or fixed. It is a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication between two components. For those skilled in the art, the specific meaning of the above-mentioned terms in the present invention can be understood according to specific circumstances.

Please refer to Figure 1, which is a schematic structural diagram of the system for preparing propylene oxide based on micro-interface enhanced propylene epoxidation according to the present invention, including a reactor 1, a micro-interface generator 2 (not shown in the figure), and a reflux Tube 3. The micro-interface generator 2 is arranged inside the reactor to break the propylene gas into micro-scale micro-sized bubbles and mix the micro-scale bubbles with the materials in the reactor to form a gas-liquid emulsion. The reflux pipe 3 is connected to the reactor 1 for preheating the propylene oxide-containing mixture after the reaction in the reactor 1 is completed, and refluxing the mixture to the reactor 1 after the preheating.

When the system is running, the oxygen source solution and the catalyst solution are first delivered into the reactor 1, and at the same time propylene gas is delivered into the reactor 1. The propylene gas will enter the micro-interface generator 2, and the micro-interface generator 2 will propylene The gas is broken to form micron-sized micro-sized bubbles and the micro-sized bubbles are mixed with the oxygen source solution to form a gas-liquid emulsion. The gas-liquid emulsion undergoes an epoxidation reaction under the action of the catalyst solution to produce a mixture containing propylene oxide. Reactor 1 The gas and residue generated during the reaction will be discharged from the system separately, and the reacted mixture will be output to the reflux pipe 3. The reflux pipe 3 preheats the mixture and then returns the mixture to the reactor 1. The oxygen source in the mixture is reused At the same time, adjust the temperature in the reactor. Those skilled in the art can understand that the micro-interface generator 2 of the present invention can also be used in other multi-phase reactions, such as via micro-interface, micro-nano interface, ultra-micro interface, micro-bubble biochemical reactor or micro-bubble biological reaction. Reactor and other equipment, using micro-mixing, micro-fluidization, ultra-micro-fluidization, micro-bubble fermentation, micro-bubble bubbling, micro-bubble mass transfer, micro-bubble transfer, micro-bubble reaction, micro-bubble absorption, micro-bubble oxygenation, micro-bubble Bubble contact and other processes or methods to make materials form multi-phase micro-mixed flow, multi-phase micro-nano flow, multi-phase emulsified flow, multi-phase micro-structured flow, gas-liquid-solid micro-mixed flow, gas-liquid-solid micro-nano flow, gas-liquid-solid emulsification Flow, gas-liquid-solid microstructure flow, micro-bubble, micro-bubble flow, micro-foam, micro-foam flow, micro-gas-liquid flow, gas-liquid micro-nano emulsion flow, ultra-micro flow, micro-dispersion flow, two micro-mixed flows, Micro-turbulent flow, micro-bubble flow, micro-bubble, micro-bubble flow, micro-nano bubble and micro-nano bubble flow and other multiphase fluids formed by micro-scale particles, or multi-phase fluids formed by micro-nano-scale particles (abbreviated as Micro-interface fluid), thereby effectively increasing the mass transfer area of the phase boundary between the gas and/or liquid phase and the liquid and/or solid phase during the reaction.

Please continue to refer to FIG. 1, the reactor 1 of the present invention includes a fully mixed flow reaction zone 11 and a plug flow reaction zone 12. The fully mixed flow reaction zone 11 is located in the lower part of the reactor 1 and is used to fully mix the oxygen source solution with micron-sized bubbles. The plug flow reaction zone 12 is located at the upper part of the reactor 1 for promoting the reaction speed in the reactor 1 and at the same time conveying the reacted mixture in a designated direction. When the reactor 1 is running, the fully mixed flow reaction zone 11 will respectively receive the oxygen source solution, the catalyst solution and the micron-sized bubbles and mix the three fully to make the propylene gas undergo the epoxidation reaction. After the reaction is completed, the fully mixed flow reaction The zone 11 transports the reaction-completed mixture to the plug flow reaction zone 12, and the plug flow reaction zone 12 transports the mixture in a designated direction. It can be understood that the aspect ratio of the plug flow reaction zone 12 is not specifically limited in this embodiment, as long as the length of the plug flow reaction zone 12 is satisfied to keep the material flowing continuously and stably.

Please continue to refer to Figure 1, the fully mixed flow biochemical reaction zone 11 of the present invention includes

The first feed pipe 111, the oxygen source feed port 112, the catalyst feed port 113, the grid 114 and the residue outlet 115. Wherein, the first feed pipe 111 is arranged on the side wall of the reactor 1 and is connected to the micro-interface generator 2 for conveying propylene gas. The oxygen source feed port 112 is arranged on the side wall of the reactor 1 to deliver the oxygen source solution to the reactor 1. The catalyst feed port 113 is arranged on the side wall of the reactor 1 and above the oxygen source feed port 112 to deliver a specified type of catalyst solution to the reactor 1. The grid 114 is arranged inside the reactor 1 to filter out the residue generated in the reactor 1 during the reaction process. The residue outlet 115 is arranged at the bottom of the reactor 1 to discharge the residue generated after the reaction out of the reactor 1.

When the fully mixed flow reaction zone 11 is operating, the oxygen source feed port 112 will deliver the oxygen source solution into the reactor 1, and the first feed pipe 111 will deliver propylene gas to the micro-interface Generator 2, micro-interface generator 2 breaks propylene gas into micron-sized micro-sized bubbles, and mixes the micro-sized bubbles with the oxygen source solution to form a gas-liquid emulsion. The gas-liquid emulsion is mixed with the catalyst solution to act on the catalyst. After the reaction is completed, the fully mixed flow reaction zone 11 will transport the reacted mixture to the plug flow reaction zone 12. During the transport process, the grid 114 will filter out the residues in the mixture. After filtering off, it begins to settle and is discharged from the reactor 1 through the residue outlet 115.

Specifically, the first feed pipe 111 is arranged on the side wall of the reactor and the outlet of the first feed pipe 111 is connected to the micro-interface generator 2 for transporting propylene gas to the micro-interface generator 2. When the fully mixed flow reaction zone 11 is running, the first feed pipe 111 will transport the propylene gas to the micro-interface generator 2, and the micro-interface generator 2 will break the propylene gas into micro-sized bubbles, and output the micro-sized bubbles to The inside of the reactor 1 is mixed with the oxygen source solution. It is understandable that the material and size of the first feed pipe 111 are not specifically limited in this embodiment, as long as the first feed pipe 111 can deliver a specified volume of propylene gas within a specified time.

Specifically, the grid 114 is a sieve plate, which is arranged inside the reactor 1 to filter the reaction mixture. When the reaction in the fully mixed flow reaction zone 11 is completed, the reacted mixture will flow through the grid 114, and the grid 114 will filter out the residue in the mixture. It can be understood that the type and the size of the through holes of the grid 114 are not specifically limited in this embodiment, as long as it is satisfied that the grid 114 can filter out solid residues in the mixture.

Please continue to refer to FIG. 1, the plug flow reaction zone 12 of the present invention is located at the upper part of the reactor 1 for conveying the reacted mixture in a specified direction, and includes a second feed pipe 121, a tail gas outlet 122, and a reflux Outlet 123, reflux feed pipe 124 and discharge port 125. Wherein, the second feed pipe 121 is arranged on the top of the reactor 1 and is connected to the micro-interface generator 2 for conveying unreacted propylene gas at the top of the reactor. The tail gas outlet 122 is arranged at the top of the reactor 1 to discharge the gas generated during the reaction. The reflux outlet 123 is located on the side wall of the reactor, and is used to output the mixture generated after the reaction to the reflux pipe 3. The reflux feed pipe 124 is arranged on the side wall of the reactor 1 and above the reflux outlet 123 to deliver the preheated mixture of the reflux pipe 3 to the reactor 1. The discharge port 125 is arranged on the side wall of the reactor 1 and above the reflux feed pipe 124 for outputting materials containing propylene oxide after the reaction.

When the plug flow reaction zone 12 is running, the mixture will be transported upwards at a constant speed in the reaction zone. When the mixture reaches the top of the reactor 1, the gas in the mixture is output to the reactor 1 through the tail gas outlet 122, and the liquid phase materials are refluxed. The outlet 123 is output to the reflux pipe 3. After the mixture is preheated by the reflux pipe 3, it is refluxed into the reactor 1 through the reflux feed pipe 124. After reflux, the second feed pipe 121 faces the micro-interface The generator 2 transports the unreacted propylene gas at the top of the reactor, and the propylene gas is mixed with the refluxed mixture after being crushed and transported to the fully mixed flow reaction zone 11 for repeated use.

Specifically, the second feed pipe 121 is arranged at the top of the reactor and the outlet of the second feed pipe 121 is connected to the micro-interface generator 2 to transport unreacted propylene gas at the top of the reactor To micro-interface generator 2. When the plug flow reaction zone 12 is running, the second feed pipe 121 will transport the propylene gas to the micro-interface generator 2, and the micro-interface generator 2 will break the unreacted propylene gas at the top of the reactor to form micron-sized bubbles. The micron-sized bubbles are output into the reactor 1 and mixed with the mixture. It is understandable that the material and size of the second feed pipe 121 are not specifically limited in this embodiment, as long as the second feed pipe 121 can deliver a specified volume of propylene gas within a specified time.

Specifically, the reflux feed pipe 124 is arranged on the side wall of the reactor 1 and the outlet of the reflux feed pipe 124 is connected to the micro-interface generator 2 for conveying the refluxed material to the micro-interface generator 2. When the horizontal plug flow biochemical reaction zone is operating, the reflux pipe 3 will transport the refluxed material to the reflux feed pipe 124, and the reflux feed pipe 124 will transport the material to the micro-interface generator 2 to make The material is mixed with micron-sized bubbles. It can be understood that the material and size of the reflux feed pipe 124 are not specifically limited in this embodiment, as long as the reflux feed pipe 124 can transport a specified flow of propylene gas within a specified time.

Please continue to refer to FIG. 1, the micro-interface generator 2 of the present invention includes a first micro-interface generator 21 and a second micro-interface generator 22. Wherein, the first micro-interface generator 21 is arranged at the bottom of the fully mixed flow reaction zone 11 to break the propylene gas to form micron-sized bubbles. The second micro-interface generator 22 is arranged on the top of the fully mixed flow reaction zone 11 and is connected to the grid 114 to break the propylene gas to form micro-sized bubbles and mix the micro-sized bubbles with the reflux mixture. When the reactor 1 is running, the first micro-interface generator 21 will break the propylene gas to form micro-sized bubbles, and mix the micro-sized bubbles with the oxygen source solution to form a gas-liquid emulsion. The generator 22 receives the refluxed mixture and the propylene gas respectively, breaks the propylene gas into micron-sized bubbles and mixes with the mixture to form a gas-liquid emulsion.

Specifically, the first micro-interface generator 21 of the present invention is a pneumatic micro-interface generator, which is connected to the first feed pipe 111 and is used for crushing and breaking the propylene gas conveyed by the first feed pipe 111. The formation of micron-sized bubbles in micron scale When the reactor 1 is in operation, the first feed pipe 111 will transport the propylene gas to the first micro-interface generator 21, and the first micro-interface generator 21 will break the propylene gas into a micron scale After the crushing is completed, the first micro-interface generator 21 will output the micron-sized bubbles into the reactor 1 and mix them with the oxygen source solution to form a gas-liquid emulsion to fully react.

Specifically, the second micro-interface generator 22 of the present invention is a gas-liquid linkage type micro-interface generator, which is connected to the second feed pipe 121 and the reflux feed pipe 124, respectively, for receiving propylene gas and The mixture is refluxed, and the pressure of the reflux mixture can break the propylene gas to form micron-scale micron-scale bubbles. When the second micro-interface generator 22 is running, it will receive propylene gas and the reflux mixture respectively, use the pressure of the reflux mixture to break the propylene gas into micron-sized bubbles, and mix the micron-sized bubbles with the refluxed mixture to form gas. The liquid emulsion is output to the fully mixed flow biochemical reaction zone 11 for repeated reactions.

Please continue to refer to FIG. 1, the return pipe 3 of the present invention includes a circulating pump 31 and a heat exchanger 32. Wherein, the circulation pump 31 is connected to the reflux outlet 123 for pumping out the reaction-completed mixture in the reactor 1. The heat exchanger 32 is connected to the circulating pump 31 for preheating the material output by the circulating pump 31. After the fermentation of the materials in the reactor 1 is completed, the circulating pump 31 starts to operate and draws the materials out through the return outlet 123, and transports the materials to the heat exchanger 32, which performs the processing on the materials After the heat exchange, the mixture is refluxed to the reflux feed pipe 124. It can be understood that the model and power of the circulating pump 31 are not specifically limited in this embodiment, as long as the circulating pump 31 can reach its designated level Working status is fine.

In order to make the purpose and advantages of the present invention clearer, the following further describes the present invention in conjunction with the embodiments; it should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

A process for preparing propylene oxide based on micro-interface enhanced propylene epoxidation, including the following steps:

Step 1: Feed the oxygen source solution into the reactor through the oxygen source feed port, and feed the catalyst solution into the reactor through the catalyst feed port;

Step 2: Transport propylene gas into the reactor through the first feed pipe, the first feed pipe will transport the propylene gas to the first micro-interface generator, and the first micro-interface generator breaks the propylene gas , Forming micron-scale micron-scale bubbles, after the crushing is completed, the first micro-interface generator outputs the micron-scale bubbles into the reactor and mixes with the oxygen source solution in the fully mixed flow reaction zone to form a gas-liquid emulsion;

Step 3: The gas-liquid emulsion reacts under the action of a catalyst to form a mixture containing propylene oxide. After the reaction is completed, the mixture flows upward into the plug flow reaction zone;

Step 4: After the mixture enters the plug flow reaction zone, it enters the reflux pipe through the reflux outlet, and the heat exchanger will heat the mixture in the pipeline to a specified temperature,

Step 5: After preheating, the mixture enters the second micro-interface generator through the reflux feed pipe. The second micro-interface generator uses the high pressure generated by the sprayed mixture to entrain the unreacted propylene gas at the top of the reactor to In the second micro-interface generator, the propylene gas is broken into micro-sized micro-sized bubbles;

Step 6: The second micro-interface generator mixes the micron-sized bubbles with the mixture to form a gas-liquid emulsion after the crushing is completed, and outputs the gas-liquid emulsion to the fully mixed flow biochemical reaction zone to make the oxygen source in the gas-liquid emulsion The solution is fully reacted;

Step 7: After the reaction is completed, propylene oxide flows upward to the plug flow reaction zone. In the plug flow reaction zone, a small amount of tail gas contained in the propylene oxide moves upward and is discharged through the tail gas outlet. The oxypropane is output from the reactor through the discharge port.

Wherein, the oxygen source solution is hydrogen peroxide solution, and the catalyst is Ts-1 titanium silicon molecular sieve. It is understandable that the range of preset operating conditions can be adjusted flexibly according to different product requirements or different catalysts to ensure the full and effective progress of the reaction, thereby ensuring the reaction rate, and achieving the purpose of strengthening the reaction. At the same time, the type of catalyst is not specifically limited in this embodiment, as long as it can ensure the smooth progress of the strengthening reaction.

Example 1

Use the above system and process to prepare propylene oxide by epoxidation of propylene, wherein:

In the process, the reaction temperature in the reactor is 20°C, the reaction pressure is 0.1 MPa, the molar ratio of propylene gas to the oxygen source solution is 1.2:1, and the catalyst space velocity is 1.20 h ^-1 .

The gas-liquid ratio in the first micro-interface generator is 1000:1, and the gas-liquid ratio in the second micro-interface generator is 400:1.

After testing, after using the system and process, _{the conversion rate of H 2} O ₂ is 97.2%, the conversion rate of propylene gas is 7.5%, and the selectivity of PO is 95.3%.

Example 2

Use the above system and process to prepare propylene oxide by epoxidation of propylene, wherein:

In the process, the reaction temperature in the reactor is 35° C., the reaction pressure is 0.2 MPa, the molar ratio of propylene gas to the oxygen source solution is 1.5:1, and the catalyst space velocity is 1.05 h ^-1 .

The gas-liquid ratio in the first micro-interface generator is 1150:1, and the gas-liquid ratio in the second micro-interface generator is 420:1.

After testing, after using the system and process, _{the conversion rate of H 2} O ₂ is 97.8%, the conversion rate of propylene gas is 7.7%, and the selectivity of PO is 95.6%.

Example 3

Use the above system and process to prepare propylene oxide by epoxidation of propylene, wherein:

In the process, the reaction temperature in the reactor is 42° C., the reaction pressure is 0.5 MPa, the molar ratio of propylene gas to the oxygen source solution is 1.9:1, and the catalyst space velocity is 0.68 h ^-1 .

The gas-liquid ratio in the first micro-interface generator is 1280:1, and the gas-liquid ratio in the second micro-interface generator is 490:1.

After testing, after using the system and process, _{the conversion rate of H 2} O ₂ is 98.1%, the conversion rate of propylene gas is 8.1%, and the selectivity of PO is 96.1%.

Example 4

Use the above system and process to prepare propylene oxide by epoxidation of propylene, wherein:

In the process, the reaction temperature in the reactor is 57° C., the reaction pressure is 0.6 MPa, the molar ratio of propylene gas to the oxygen source solution is 2.3:1, and the catalyst space velocity is 0.41 h ^-1 .

The gas-liquid ratio in the first micro-interface generator is 1390:1, and the gas-liquid ratio in the second micro-interface generator is 530:1.

After testing, after using the system and process, _{the conversion rate of H 2} O ₂ is 98.5%, the conversion rate of propylene gas is 8.2%, and the selectivity of PO is 96.4%.

Example 5

Use the above system and process to prepare propylene oxide by epoxidation of propylene, wherein:

In the process, the reaction temperature in the reactor is 70° C., the reaction pressure is 0.8 MPa, the molar ratio of propylene gas to the oxygen source solution is 2.5:1, and the catalyst space velocity is 0.12 h ^-1 .

The gas-liquid ratio in the first micro-interface generator is 1500:1, and the gas-liquid ratio in the second micro-interface generator is 600:1.

After testing, after using the system and process, _{the conversion rate of H 2} O ₂ is 98.8%, the conversion rate of propylene gas is 8.5%, and the selectivity of PO is 96.7%.

Comparison

The prior art is used to carry out propylene epoxidation to prepare propylene oxide, wherein the process parameters selected in this embodiment are the same as the process parameters in the fifth embodiment.

After testing, after using the system and process, _{the conversion rate of H 2} O ₂ is 95.9%, the conversion rate of propylene gas is 7.5%, and the selectivity of PO is 95.0%.

So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the drawings. However, those skilled in the art will readily understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

The above descriptions are only preferred embodiments of the present invention and are not used to limit the present invention; for those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A system for preparing propylene oxide based on micro-interface enhanced propylene epoxidation, which is characterized in that it comprises:

   The reactor is used to provide a reaction place for the propylene gas and the oxygen source solution, and the reactor includes a fully mixed flow arranged below to load the propylene gas, the oxygen source solution and the catalyst and provide a reaction space for the propylene gas and the oxygen source solution The reaction zone and the plug flow reaction zone set up above to transport and separate the gas and liquid after the reaction is completed;

   The micro-interface generator, which is set at a designated position in the fully mixed flow reaction zone, converts the pressure energy of the gas and/or the kinetic energy of the liquid into the surface energy of the bubble and transmits it to the propylene gas, so that the propylene gas is broken to form a diameter ≥ 1 μm, And <1mm micron-level bubbles to increase the mass transfer area between the oxygen source solution and propylene gas, reduce the thickness of the liquid film, reduce the mass transfer resistance, and mix the oxygen source solution with the micron-level bubbles to form a gas-liquid emulsion after being broken , To enhance the mass transfer efficiency and reaction efficiency between the oxygen source solution and the propylene gas within the preset operating conditions;

   A reflux pipe, which is set on the side wall of the reactor, is used to preheat the material output from the reactor and return it to the reactor after preheating so that the oxygen source solution in the material can fully react and the temperature of the material in the reactor Make adjustments.
2. The system for preparing propylene oxide based on micro-interface enhanced propylene epoxidation according to claim 1, wherein the micro-interface generator comprises:

   The first micro-interface generator is a pneumatic micro-interface generator. The first micro-interface generator is arranged in the fully mixed flow reaction zone and located at the bottom of the reaction zone, and is used to break the propylene gas into micron-sized micrometers. After the crushing is completed, the micron-level bubbles are output to the reactor and mixed with the oxygen source solution in the reactor to form a gas-liquid emulsion;

   A second micro-interface generator, which is a hydraulic or gas-liquid linkage type micro-interface generator, the second micro-interface generator is arranged in the fully mixed flow reaction zone to receive the material output by the return pipe, The material is used to entrain the unreacted propylene gas in the plug flow reaction zone and the propylene gas is broken to form micron-sized micro-sized bubbles, the micro-sized bubbles are mixed with the material to form a gas-liquid emulsion, and the gas-liquid emulsion is output to the whole The mixed-flow biochemical reaction zone is opposed to the gas-liquid emulsion output by the first micro-interface generator, so as to extend the residence time of micron-sized bubbles in the mixed-flow biochemical reaction zone and cause the propylene gas to undergo a secondary reaction.
3. The system for preparing propylene oxide based on micro-interface enhanced propylene epoxidation according to claim 2, wherein the fully mixed flow reaction zone comprises:

   The first feed pipe is arranged on the side wall of the reactor and is connected to the first micro-interface generator, and is used to deliver propylene gas to the first micro-interface generator so that the first micro-interface generator reacts to propylene. Gas is broken;

   An oxygen source feed port, which is arranged on the side wall of the reactor and above the first feed pipe, and is used to deliver the oxygen source solution to the inside of the reactor;

   A catalyst feed port, which is arranged on the side wall of the reactor and above the oxygen source feed port, and is used to transport the catalyst solution to the inside of the reactor;

   The residue outlet, which is arranged at the bottom of the reactor, is used to discharge the residue generated during the reaction process of the materials in the reactor.
4. The system for preparing propylene oxide based on micro-interface enhanced propylene epoxidation according to claim 2, wherein the plug flow reaction zone comprises:

   The second feed pipe is arranged in the reactor, and the bottom end of the second feed pipe is connected with the second micro-interface generator, and the top end of the second feed pipe is located above the liquid level in the reactor, Used to entrain the unreacted propylene gas at the top of the reactor to the second micro-interface generator so that the second micro-interface generator breaks the propylene gas;

   A discharging port, which is arranged on the side wall of the reactor to output the material containing propylene oxide out of the reactor;

   A reflux outlet, which is arranged on the side wall of the reactor, and is used to output the reaction-completed mixture containing propylene oxide to the reflux pipe;

   The reflux feed pipe is arranged on the side wall of the reactor and the two ends of the reflux feed pipe are respectively connected with the second micro-interface generator and the reflux pipe to output the preheated mixture in the reflux pipe to the second Two micro-interface generators;

   The tail gas outlet, which is arranged at the top of the reactor, is used to discharge the tail gas generated after the reaction of the materials in the reactor.
5. The system for preparing propylene oxide based on micro-interface enhanced propylene epoxidation according to claim 2, wherein the return pipe comprises:

   A circulating pump, which is connected to the reactor, and is used to output the reaction-completed mixture in the reactor;

   The heat exchanger is connected with the circulation pump and is used to exchange heat for the mixture output by the circulation pump to maintain the mixture within a preset temperature range.
6. The system for preparing propylene oxide based on micro-interface enhanced propylene epoxidation according to claim 5, wherein the outlet of the heat exchanger is connected to the second micro-interface generator for preheating the mixture Output to the second micro-interface generator.
7. A process for preparing propylene oxide based on micro-interface enhanced propylene epoxidation, which is characterized in that it comprises:

   Step 1: Feed the oxygen source solution into the reactor through the oxygen source feed port, and feed the catalyst solution into the reactor through the catalyst feed port;

   Step 2: Transport propylene gas into the reactor through the first feed pipe, the first feed pipe will transport the propylene gas to the first micro-interface generator, and the first micro-interface generator breaks the propylene gas , Forming micron-scale micron-scale bubbles, after the crushing is completed, the first micro-interface generator outputs the micron-scale bubbles into the reactor and mixes with the oxygen source solution in the fully mixed flow reaction zone to form a gas-liquid emulsion;

   Step 3: The gas-liquid emulsion reacts under the action of the catalyst solution to generate a mixture containing propylene oxide. After the reaction is completed, the mixture flows upward into the plug flow reaction zone;

   Step 4: After the mixture enters the plug flow reaction zone, it enters the reflux pipe through the reflux outlet, and the heat exchanger will heat the mixture in the pipeline to a specified temperature,

   Step 5: After preheating, the mixture enters the second micro-interface generator through the reflux feed pipe. The second micro-interface generator uses the high pressure generated by the sprayed mixture to entrain the unreacted propylene gas at the top of the reactor to In the second micro-interface generator, the propylene gas is broken into micro-sized micro-sized bubbles;

   Step 6: The second micro-interface generator mixes the micron-sized bubbles with the mixture to form a gas-liquid emulsion after the crushing is completed, and outputs the gas-liquid emulsion to the fully mixed flow biochemical reaction zone to fully react in the gas-liquid emulsion;

   Step 7: After the reaction is completed, propylene oxide flows upward to the plug flow reaction zone. In the plug flow reaction zone, a small amount of tail gas contained in the propylene oxide moves upward and is discharged through the tail gas outlet. The oxypropane is output from the reactor through the discharge port.
8. The process for preparing propylene oxide based on micro-interface intensified epoxidation of propylene according to claim 7, characterized in that the remaining residue of the gas-liquid emulsion after the reaction in the step 3 will settle to the bottom of the reactor and The reactor is discharged through the residue outlet.
9. The process for preparing propylene oxide based on micro-interface enhanced propylene epoxidation according to claim 7, wherein the reaction temperature in the reactor in the process is 20-70° C., and the reaction pressure is 0.1-0.8 MPa.
10. The process for preparing propylene oxide based on micro-interface enhanced propylene epoxidation according to claim 7, wherein the gas-liquid ratio in the first micro-interface generator is 1000-1500:1, and the second The gas-liquid ratio in the micro-interface generator is 400-600:1.

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