HPPO process propylene oxide reactor and propylene oxide production method

Abstract

The present invention relates to a HPPO process propylene oxide reactor and a propylene oxide production method. The reactor comprises, from bottom to top, a raw material zone, a reaction zone, and a product zone. The reaction zone is provided with a plurality of hollow tubes and a plurality of ultrasonic transducers. The hollow tubes are filled with a catalyst. The hollow tubes connect the raw material zone and the product zone. The raw material zone is connected to a feed pipe, a propylene pipeline and an alcohol-water pipeline are connected to the feed pipe, a cold source inlet and a cold source outlet are provided in the reaction zone, and a discharge pipe is connected to the product zone. The present invention reduces the intensity of the initial reaction in the reactor, makes the reaction temperature easy to control, reduces the decomposition of hydrogen peroxide, and improves the selectivity of propylene oxide. The reaction heat can be removed in a timely manner, reduces the carbon accumulation on the catalyst surface, improves the catalytic efficiency of the catalyst, and prolongs the service life of the catalyst. In addition, the carbon accumulation on the catalyst surface can be directly removed by ultrasonic waves.

Description

Technical Field

[0001] The present invention relates to propylene oxide production equipment, in particular to a HPPO process propylene oxide reactor and a propylene oxide production method. Background Art

[0002] Propylene oxide (PO), also known as methyl oxirane or propylene oxide, is a colorless, ether-smelling liquid with a low boiling point and is flammable. It is chiral, and industrial products are generally racemic mixtures of its two enantiomers. It is partially miscible with water and miscible with ethanol and ether. It forms binary azeotropic mixtures with pentane, pentene, cyclopentane, cyclopentene, and dichloromethane. It is an important raw material and synthetic intermediate for organic chemical synthesis. Its active chemical properties allow for easy ring-opening polymerization, reacting with water, ammonia, alcohols, and carbon dioxide to form corresponding compounds or polymers. It is the third most common propylene derivative after polypropylene and acrylonitrile. It is primarily used in the production of polyether polyols, propylene glycol, and various nonionic surfactants. Polyether polyols are important raw materials for the production of polyurethane foams, insulation materials, elastomers, adhesives, and coatings, while various nonionic surfactants are widely used in the petroleum, chemical, pesticide, textile, and daily chemical industries. Due to its wide range of applications, PO has become a hot product in recent years.

[0003] Currently, the mainstream production processes for propylene oxide include the chlorohydrin method, ethylbenzene co-oxidation method, and hydrogen peroxide direct oxidation method (Hydrogene peroxide propylene oxide, referred to as "HPPO").

[0004] Due to the high corrosiveness of the chlorohydrin process, large amounts of "three wastes" emissions, serious environmental pollution, and difficulty in comprehensive management, it was listed as restricted for development as early as in the "Guiding Catalogue for Industrial Structure Adjustment (2011)".

[0005] The ethylbenzene co-oxidation method requires both ethylene and propylene resources. The process investment is high, the process is complex, and it is highly dependent on raw material resources. Therefore, it can generally only be configured in large-scale ethylene projects. In addition, every ton of propylene oxide produced can co-produce about 2.2 tons of styrene.

[0006] The HPPO process requires propylene as its primary raw material, which is more readily available than ethylene and has no by-products. It also minimizes the emission of "three wastes," making it the greenest process. Its production process is relatively simple, requiring lower investment than co-oxidation, and it lacks by-product constraints. The HPPO process is currently a hot topic among propylene oxide researchers.

[0007] Most existing HPPO processes for propylene oxide production utilize a fixed-bed reactor. Under pressure, propylene reacts with hydrogen peroxide in the presence of a catalyst using methanol as the solvent to produce propylene oxide and water. The raw materials, propylene, hydrogen peroxide, and methanol, are added from the top of the fixed-bed reactor, which is loaded with a catalyst in the middle. As the raw materials flow downward, they react over the catalyst surface to produce propylene oxide and water. Because this reaction is highly exothermic, a cooling source is introduced outside the catalyst loading tube to control localized temperature fluctuations and the flow rate of the raw materials. This allows for the timely removal of reaction heat. The propylene oxide and aqueous solution are obtained at the bottom of the reactor and sent to subsequent refining processes.

[0008] During the reaction process, since the reaction is a highly exothermic reaction, the reaction is more intense on the upper catalyst surface, the temperature is higher, the catalyst surface is seriously carbonized, the catalyst pores are blocked, the catalytic efficiency is affected, and the life of the catalyst is short. On the middle catalyst surface, since the raw materials have reacted partially, the reaction is less intense than that on the upper catalyst surface, and the temperature is slightly lower. On the lower catalyst surface, most of the raw materials have completed the reaction at this time, the catalyst surface reaction is relatively mild, and the reaction heat generated by the reaction is relatively small. In summary, the reaction heat generated at different positions of the catalyst, the upper, middle and lower parts, is different, resulting in different reaction temperatures at different locations. After a period of reaction, due to the low catalytic efficiency of the upper catalyst, the main reaction is concentrated in the middle catalyst and the lower catalyst. At this time, the reaction temperature in the middle is high, and the reaction temperatures in the upper and lower parts are relatively low. In short, in the existing fixed-bed reactor, the reaction temperatures at different locations are different, the temperature fluctuation range is large, and the reaction temperature is difficult to control and balance.

[0009] Due to the high reaction temperature, the carbon deposits on the catalyst surface are serious and the catalyst life is short. The catalyst needs to be regenerated frequently. The regeneration of the catalyst requires stopping production and performing online regeneration to remove the carbon deposits on the catalyst surface. Frequent regeneration limits the production efficiency of propylene oxide.

[0010] Furthermore, the high temperature also produces various byproducts, increasing the pressure of subsequent refining. The hydrogen peroxide inevitably decomposes to release a small amount of oxygen. To prevent the dangerous accumulation of oxygen within the reactor, nitrogen is introduced from the top, which then carries the oxygen out from the bottom while maintaining a stable pressure within the reactor. A phase separator is also installed at the bottom of the reactor to separate the light propylene phase from the heavy propylene oxide aqueous solution. This results in a complex equipment structure, increasing the complexity and risk of the reaction. Summary of the Invention

[0011] The purpose of the present invention is to provide a HPPO process propylene oxide reactor and a propylene oxide production method to solve the problems of the existing HPPO process propylene oxide reactor in that the reaction temperature is difficult to control, the catalyst life is short, the by-products are large and the subsequent refining pressure is high.

[0012] The present invention is achieved as follows: a HPPO process propylene oxide reactor comprises a reactor, wherein the reactor is sequentially divided into a raw material zone, a reaction zone and a product zone from bottom to top; a plurality of hollow tubes and a plurality of ultrasonic transducers are provided in the reaction zone; a catalyst is filled in the hollow tubes; the hollow tubes connect the raw material zone and the product zone; a feed pipe is connected to the raw material zone; a propylene pipeline and an alcohol-water pipeline are connected to the feed pipe; a cold source inlet and a cold source outlet are provided in the reaction zone; and a discharge pipe is connected to the product zone.

[0013] The hollow tube comprises, from bottom to top, a first filling layer, a second filling layer and a third filling layer, wherein the first filling layer, the second filling layer and the third filling layer are filled with a mixture of a solid catalyst and a solid catalyst substitute, and the proportion of the content of the solid catalyst in the second filling layer to the volume of the mixture is greater than the proportion of the content of the solid catalyst in the first filling layer to the volume of the mixture and the proportion of the content of the solid catalyst in the third filling layer to the volume of the mixture.

[0014] The content of the solid catalyst in the first filling layer accounts for 15-30% of the volume of the mixture, the content of the solid catalyst in the second filling layer accounts for 45-55% of the volume of the mixture, and the content of the solid catalyst in the third filling layer accounts for 15-25% of the volume of the mixture.

[0015] A first partition and a second partition are arranged at the gap between the hollow tubes in the reaction zone. The first partition corresponds to the junction of the first filling layer and the second filling layer, and the second partition corresponds to the junction of the second filling layer and the third filling layer. The first partition and the second partition divide the reaction zone into a first reaction zone, a second reaction zone and a third reaction zone from bottom to top. A cold source inlet, a cold source outlet and a temperature monitoring port are respectively provided in the first reaction zone, the second reaction zone and the third reaction zone.

[0016] A static mixer is provided on the feed pipe.

[0017] A liquid level monitoring port, a pressure monitoring port and a safety valve installation port are provided in the product area.

[0018] A flow meter and a regulating valve are respectively provided on the propylene pipeline and the alcohol-water pipeline.

[0019] The present invention also discloses a method for producing propylene oxide, which is implemented based on the above-mentioned HPPO method propylene oxide reactor and includes the following steps.

[0020] a. Fill the hollow tube of the reactor with a mixture of catalyst and solid catalyst substitute, fill the lower part of the hollow tube with a mixture having a catalyst volume content of 15-30% to form a first filling layer, fill the middle part of the hollow tube with a mixture having a catalyst volume content of 45-55% to form a second filling layer, and fill the upper part of the hollow tube with a mixture having a catalyst volume content of 15-25% to form a third filling layer.

[0021] b. Assemble and obtain the HPPO process propylene oxide reactor.

[0022] c. The raw material propylene solution is input through the propylene pipeline, and the raw material methanol and hydrogen peroxide solution are input through the alcohol-water pipeline. The raw material propylene solution is mixed with the raw material methanol and hydrogen peroxide solution and then enters the raw material area of ​​the reactor. At the same time, cold sources are injected into the first reaction zone, the second reaction zone, and the third reaction zone through each cold source inlet.

[0023] d. The mixed solution in the raw material zone flows upward and enters the hollow tube from the lower end of the hollow tube. With methanol as the solvent, under the action of the catalyst, propylene and hydrogen peroxide undergo propylene epoxidation reaction to generate propylene oxide and water, which are discharged from the upper end of the hollow tube to the product zone to obtain a mixed solution containing propylene oxide, water, propylene and methanol.

[0024] e. The mixed solution containing propylene oxide, water, propylene and methanol is transported to the subsequent process through the discharge pipe.

[0025] f. Start the ultrasonic transducer regularly to remove carbon deposits on the catalyst surface.

[0026] The pressure in the reactor is controlled to be 2.4-2.8Mpa, and the reaction temperature in the first reaction zone, the second reaction zone, and the third reaction zone is controlled to be 45-60°C. The reaction temperature is controlled by adjusting the flow rate and flow velocity of the cold source in the first reaction zone, the second reaction zone, and the third reaction zone.

[0027] The solid catalyst substitute is a glass ball or a glazed ceramic ball without catalytic and adsorption functions, and has the same appearance as the solid catalyst.

[0028] The invention provides a mixed solution of hydrogen peroxide, methanol and propylene added to a raw material zone at the bottom, and the mixed solution of hydrogen peroxide, methanol and propylene passes from bottom to top through a hollow tube filled with a catalyst in a reaction zone. With methanol as a solvent and under the action of the catalyst, propylene and hydrogen peroxide undergo propylene epoxidation reaction in the hollow tube to generate propylene oxide and water. A mixed solution mainly containing propylene oxide, water, propylene and methanol is obtained in a product zone. The mixed solution is discharged through a discharge pipe and then sent to a subsequent treatment process for treatment.

[0029] The hollow tube of the present invention is divided into a first filling layer, a second filling layer, and a third filling layer. The corresponding outer portion of the first filling layer is a first reaction zone, the outer portion of the second filling layer is a second reaction zone, and the outer portion of the third filling layer is a third reaction zone. The catalyst content in each filling layer is different, and the mixed solution passes through the first filling layer, the second filling layer, and the third filling layer in sequence. Since the catalyst content in the first filling layer at the bottom is relatively low, the intensity of the reaction on the catalyst surface can be greatly reduced compared to a fully loaded catalyst, and the reaction heat generated by the propylene epoxidation reaction can be promptly removed via a heat sink in the first reaction zone; the catalyst content in the second filling layer at the middle is relatively high, and unreacted propylene in the feedstock and hydrogen peroxide react on the catalyst surface, and the reaction heat generated by the reaction can also be promptly removed via a heat sink in the second reaction zone; the catalyst content in the third filling layer at the top is relatively low, and at this time, most of the propylene and hydrogen peroxide have reacted, and a small amount of catalyst is required, so the reaction heat generated by the reaction is relatively low, and the reaction heat can also be promptly removed by a heat sink in the third reaction zone. In the present invention, the reaction zone is divided into three reaction zones: a first reaction zone, a second reaction zone, and a third reaction zone. Each of the three reaction zones is provided with its own heat sink. By adjusting the flow rate and flow rate of the heat sink in each reaction zone, the temperatures of the three reaction zones can be controlled to be consistent, thereby ensuring the safety of the reaction and reducing the occurrence of side reactions. The present invention can quickly remove the reaction heat, control the temperature of the propylene epoxidation reaction in the reactor within the process requirements, and make the reaction temperature of each section in the hollow tube consistent, making the reaction temperature easy to control, improving the safety of the reaction, reducing the decomposition of hydrogen peroxide, and improving the selectivity of propylene oxide; reducing carbon accumulation on the catalyst surface and extending the service life of the catalyst; reducing the occurrence of side reactions and reducing the pressure of the subsequent refining process.

[0030] The present invention removes carbon deposits on the catalyst surface through ultrasound, replacing the catalyst online regeneration pipeline system, and does not require shutdown when removing carbon deposits, thereby increasing the production capacity of a single device and improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural diagram of the present invention.

[0032] Figure 2 It is a structural diagram of the reactor of the present invention.

[0033] Figure 3 yes Figure 2 AA view.

[0034] In the figure: 1. Reactor; 2. Feed pipe; 3. Propylene pipeline; 4. Alcohol-water pipeline; 5. Static mixer; 6. Discharge pipe; 7. Control valve; 8. Flow meter;

[0035] 101. Raw material area; 102. Reaction area; 103. Product area; 104. Raw material inlet; 105. Cold source inlet; 106. Temperature monitoring port; 107. Liquid level monitoring port; 108. Pressure monitoring port; 109. Reactant discharge port; 110. Safety valve installation port; 111. Hollow tube; 112. Ultrasonic transducer; 113. Cold source outlet; 114. First filling layer; 115. Second filling layer; 116. Third filling layer; 117. Flower disk; 118. First partition; 119. Second partition; 1021. First reaction zone; 1022. Second reaction zone; 1023. Third reaction zone. DETAILED DESCRIPTION

[0036] like Figure 1 As shown, the present invention includes a reactor 1, which includes a raw material area 101, a reaction area 102 and a product area 103 from bottom to top. A plurality of hollow tubes 111 and a plurality of ultrasonic transducers 112 are provided in the reaction area 102. The hollow tubes 111 are filled with catalysts. The hollow tubes 111 connect the raw material area 101 and the product area 103. The raw material area 101 is connected to a feed pipe 2, and the feed pipe 2 is connected to a propylene pipeline 3 and an alcohol-water pipeline 4. A cold source inlet 105 and a cold source outlet 113 are provided in the reaction area 102, and a discharge pipe 6 is connected to the product area 103.

[0037] Among them, Figure 2 、 Figure 3 As shown, flange-type faceplates 117 are provided at both ends of the reaction zone 102, the upper end of the feed zone 101, and the lower end of the product zone 103. The hollow tube 111 is parallel to the axis of the reaction zone 102. The upper and lower ends of the hollow tube 111 are respectively welded to the faceplates 117. The feed zone 101, the reaction zone 102, and the product zone 103 are detachably connected via the faceplates 117. The feed zone 101 and the product zone 103 are detachably mounted on the reaction zone 102, facilitating the loading and unloading of the catalyst in the hollow tube 111.

[0038] The side wall of the reaction zone 102 is a cylindrical structure. The hollow tube 111 and the ultrasonic transducer 112 are both located inside the side wall of the reaction zone 102. The hollow tube 111 is used for the passage and reaction of the mixed liquid, while the outside of the hollow tube 111 is used for the storage and flow of the cold source, thereby cooling the hollow tube 111 and controlling the reaction temperature within the process requirements.

[0039] The inner cavity of the hollow tube 111 is composed of a first filling layer 114, a second filling layer 115, and a third filling layer 116 from bottom to top. The first filling layer 114, the second filling layer 115, and the third filling layer 116 are filled with a mixture of a solid catalyst and a solid catalyst substitute. The proportion of the solid catalyst content in the second filling layer to the volume of the mixture is greater than the proportion of the solid catalyst content in the first filling layer to the volume of the mixture and the proportion of the solid catalyst content in the third filling layer to the volume of the mixture.

[0040] Specifically, the solid catalyst content in the first filling layer 114 accounts for 15-30% of the mixture volume, the solid catalyst content in the second filling layer 115 accounts for 45-55% of the mixture volume, and the solid catalyst content in the third filling layer 116 accounts for 15-25% of the mixture volume.

[0041] A first partition 118 and a second partition 119 are arranged in the gap of the hollow tube 111 in the reaction zone. The first partition 118 corresponds to the junction of the first filling layer 114 and the second filling layer 115, and the second partition 119 corresponds to the junction of the second filling layer 115 and the third filling layer 116. The first partition 118 and the second partition 119 divide the reaction zone into a first reaction zone 1021, a second reaction zone 1022 and a third reaction zone 1023 from bottom to top. A cold source inlet 105, a cold source outlet 113 and a temperature monitoring port 106 are respectively provided in the first reaction zone 1021, the second reaction zone 1022 and the third reaction zone 1023.

[0042] The cold source inlet 105 is located at the lower part of the side wall of each reaction zone, and the cold source outlet 113 is located at the upper part of the side wall of each reaction zone.

[0043] A cold source is injected into each reaction zone through the cold source inlet 105 , and the cold source absorbs the heat generated by the reaction to control the temperature of each reaction zone.

[0044] A raw material inlet 104 is provided at the bottom of the raw material zone 101 , and the raw material inlet 104 is connected to the feed pipe 2 .

[0045] A liquid level monitoring port 107 is provided on the side wall of the product area 103 , and a pressure monitoring port 108 , a reactant discharge port 109 and a safety valve installation port 110 are provided on the top of the product area 103 . The reactant discharge port 109 is connected to the discharge pipe 6 .

[0046] The solid catalyst substitute is a solid such as a glass ball, a glazed ceramic ball, etc. which has no catalytic and adsorption functions and has the same appearance as the solid catalyst.

[0047] Since the hollow tube 111 of the present invention is divided into a first filling layer 114, a second filling layer 115 and a third filling layer 116, the outside of the corresponding first filling layer 114 is the first reaction zone 1021, the outside of the second filling layer 115 is the second reaction zone 1022, and the outside of the third filling layer 116 is the third reaction zone 1023, the catalyst content in each filling layer is different. When the mixed solution passes through the first filling layer 114, the second filling layer 115 and the third filling layer 116 in sequence, the catalyst content in the first filling layer 114 located at the bottom is relatively low, which can greatly reduce the intensity of the reaction on the catalyst surface. The reaction heat generated by the propylene epoxidation reaction can be promptly removed through the cooling source of the first reaction zone 1021; the catalyst content in the second filling layer 115 located in the middle is relatively high, and the unreacted propylene and hydrogen peroxide in the raw materials react on the catalyst surface. The reaction heat generated by the reaction can also be promptly removed through the cooling source of the second reaction zone 1022; the catalyst content in the third filling layer 116 above is relatively low. At this time, most of the propylene and hydrogen peroxide have reacted, and a small amount of them have not reacted. The amount of catalyst required is also small, and the reaction heat generated by the reaction is relatively small. The reaction heat can also be promptly removed by the cooling source of the third reaction zone 1023.

[0048] By filling different sections of the hollow tube 111 with different contents of catalyst and dividing the exterior of the different sections into different reaction zones, the reaction heat of each section can be quickly removed and the reaction temperature of each section can be controlled to be the same, so that the temperature of the propylene epoxidation reaction in the reactor 1 is uniformly controlled within the process requirements. The reaction temperature of each section is made the same and easy to control, which reduces the decomposition of hydrogen peroxide and improves the selectivity of propylene oxide. It also reduces carbon accumulation on the catalyst surface and extends the service life of the catalyst. It also reduces the occurrence of side reactions and reduces the pressure of the subsequent refining process.

[0049] A static mixer 5 is installed on the feed pipe 2. A flow meter 8 and a regulating valve 7 are installed on the propylene line 3 and the alcohol-water line 4, respectively. The alcohol-water line 4 is used to add the raw materials methanol and hydrogen peroxide, with the flow rate and flow rate of the raw materials methanol and hydrogen peroxide controlled by the flow meter 8 and regulating valve 7. The propylene line 3 is used to add the raw material propylene, with the flow rate and flow rate of the raw material propylene controlled by the flow meter 8 and regulating valve 7. The static mixer 5 thoroughly mixes the raw materials methanol and hydrogen peroxide with the raw material propylene, and then delivers them to the raw material area 101 through the feed pipe 2.

[0050] Ultrasonic transducer 112 is an ultrasonic vibrator. The ultrasonic waves generated by the ultrasonic vibrator can remove carbon deposits from the catalyst surface, ensuring catalytic efficiency and extending the catalyst's service life. Furthermore, since ultrasonic waves are used to remove carbon deposits from the catalyst, the existing online catalyst regeneration piping system is replaced. Only the ultrasonic transducer 112 needs to be activated periodically to remove carbon deposits from the catalyst, and catalyst regeneration can be completed without shutting down the system. This reduces the impact on production, increases the production capacity of a single unit, and improves production efficiency.

[0051] In the present invention, a mixed solution of hydrogen peroxide, methanol and propylene is added to the lower raw material zone 101. The mixed solution of hydrogen peroxide, methanol and propylene passes from bottom to top through a hollow tube 111 filled with a catalyst in the reaction zone 102. With methanol as the solvent and under the action of the catalyst, propylene and hydrogen peroxide undergo propylene epoxidation reaction to generate propylene oxide and water. A mixed solution mainly containing propylene oxide, water, propylene and methanol is obtained in the product zone 103. The mixed solution is discharged through the discharge pipe 6 and sent to a subsequent treatment process.

[0052] The present invention also discloses a method for producing propylene oxide, which is implemented by using the above-mentioned HPPO method propylene oxide reactor 1 and includes the following steps.

[0053] a. A mixture of a solid catalyst and a solid catalyst substitute is filled into the hollow tube 111 of the reactor 1, and a mixture with a catalyst volume content of 15-30% is filled into the lower part of the hollow tube 111 to form a first filling layer 114. A mixture with a catalyst volume content of 45-55% is filled into the middle part of the hollow tube 111 to form a second filling layer 115. A mixture with a catalyst volume content of 15-25% is filled into the upper part of the hollow tube 111 to form a third filling layer 116.

[0054] b. Assemble and obtain the HPPO process propylene oxide reactor.

[0055] c. The raw material propylene solution is input through the propylene pipeline 3, and the raw material methanol and hydrogen peroxide solution are input through the alcohol-water pipeline 4. The raw material propylene solution is mixed with the raw material methanol and hydrogen peroxide solution and then enters the raw material area 101 of the reactor 1. At the same time, cold sources are injected into the first reaction zone 1021, the second reaction zone 1022 and the third reaction zone 1023 respectively through each cold source inlet 105.

[0056] d. The mixed solution in the feed zone 101 flows upward and enters the lower end of the hollow tube 111. With methanol as the solvent, propylene and hydrogen peroxide undergo propylene epoxidation reaction in the hollow tube under the action of the catalyst to produce propylene oxide and water, which are then discharged from the upper end of the hollow tube 111 to the product zone 103 to obtain a mixed solution containing propylene oxide, water, propylene, and methanol.

[0057] e. The mixed solution containing propylene oxide, water, propylene and methanol is transported to the subsequent process through the discharge pipe 6.

[0058] f. Regularly start the ultrasonic transducer 112 to remove carbon deposits on the catalyst surface.

[0059] The pressure in the reactor 1 is controlled to be 2.4-2.8 MPa, and the reaction temperatures of the first reaction zone 1021, the second reaction zone 1022 and the third reaction zone 1023 are controlled to be 45-60°C. The reaction temperature is controlled by adjusting the flow rate and flow velocity of the cold source in each reaction zone.

[0060] The pressure in the reactor 1 can be controlled by the discharge rate of the product, and the discharge rate of the product is controlled by the regulating valve 7 on the discharge pipe 6.

[0061] Solid catalyst replacements are solid materials such as glass spheres and glazed ceramic spheres that lack catalytic and adsorption properties. The shape and size of the solid catalyst replacements match the solid catalyst. The filling mixture is created by thoroughly mixing the solid catalyst replacement with the catalyst. By controlling the ratio of the solid catalyst replacement to the catalyst, different filling layers can be achieved.

[0062] Since the catalyst content in the first filling layer 114 is relatively low, at only 15-30%, the intensity of the reaction on the catalyst surface can be significantly reduced compared to a full catalyst loading, and the reaction heat generated by the propylene epoxidation reaction can be promptly removed via the cooling source of the first reaction zone 1021. The catalyst content in the second filling layer 115 is slightly higher, at 45-55%. Unreacted propylene and hydrogen peroxide in the feed react on the catalyst surface, and the reaction heat generated by the reaction can also be promptly removed via the cooling source of the second reaction zone 1022. The catalyst content in the third filling layer 116 is relatively low, at only 15-25%. At this time, most of the propylene and hydrogen peroxide have reacted, and a small amount remains unreacted. The amount of catalyst required is also small, and the reaction heat generated by the reaction is relatively small, which can also be promptly removed by the cooling source of the third reaction zone 1023.

[0063] The beneficial effects achieved by the present invention are:

[0064] 1. The present invention adopts segmented loading of catalysts with different contents, which can reduce the intensity of the initial reaction in the reactor, make the reaction temperature easier to control, reduce the decomposition of hydrogen peroxide, and improve the selectivity of propylene oxide.

[0065] 3. In the present invention, since the catalyst contents in the upper, middle and lower parts are different, the reaction area is correspondingly divided into the first to third reaction zones. Each reaction zone is provided with a separate cold source. The reaction heat of each reaction zone can be removed in time and the temperature of the three reaction zones can be controlled to be consistent, thereby reducing the carbon accumulation on the catalyst surface, reducing the occurrence of side reactions, reducing by-products, reducing the subsequent refining pressure, and improving the catalytic efficiency of the catalyst, extending the service life of the catalyst, and reducing the regeneration frequency of the catalyst.

[0066] 4. In the present invention, the decomposition rate of hydrogen peroxide is low and the conversion rate is high. The conversion rate of hydrogen peroxide is ≥98%, and the selectivity of propylene oxide is ≥98%.

[0067] 5. The present invention removes carbon deposits on the catalyst surface through ultrasound without interrupting production. The catalyst can be regenerated during production, thereby increasing the production capacity of a single device and improving production efficiency.

Claims

1. A HPPO process propylene oxide reactor, characterized in that, The reactor comprises a raw material zone, a reaction zone and a product zone from bottom to top, wherein a plurality of hollow tubes and a plurality of ultrasonic transducers are provided in the reaction zone, a catalyst is filled in the hollow tubes, the hollow tubes connect the raw material zone and the product zone, the raw material zone is connected to a feed pipe, a propylene pipeline and an alcohol-water pipeline are connected to the feed pipe, a cold source inlet and a cold source outlet are provided in the reaction zone, and a discharge pipe is connected to the product zone; The hollow tube comprises, from bottom to top, a first filling layer, a second filling layer, and a third filling layer, wherein the first filling layer, the second filling layer, and the third filling layer are filled with a mixture of a solid catalyst and a solid catalyst substitute, and the ratio of the content of the solid catalyst in the second filling layer to the volume of the mixture is greater than the ratio of the content of the solid catalyst in the first filling layer to the volume of the mixture and the ratio of the content of the solid catalyst in the third filling layer to the volume of the mixture; The content of the solid catalyst in the first filling layer accounts for 15-30% of the volume of the mixture, the content of the solid catalyst in the second filling layer accounts for 45-55% of the volume of the mixture, and the content of the solid catalyst in the third filling layer accounts for 15-25% of the volume of the mixture; A first partition and a second partition are arranged at the gap between the hollow tubes in the reaction zone. The first partition corresponds to the junction of the first filling layer and the second filling layer, and the second partition corresponds to the junction of the second filling layer and the third filling layer. The first partition and the second partition divide the reaction zone into a first reaction zone, a second reaction zone and a third reaction zone from bottom to top. A cold source inlet, a cold source outlet and a temperature monitoring port are respectively provided in the first reaction zone, the second reaction zone and the third reaction zone.

2. The HPPO process propylene oxide reactor according to claim 1, wherein A static mixer is provided on the feed pipe.

3. The HPPO process propylene oxide reactor according to claim 1, wherein A liquid level monitoring port, a pressure monitoring port and a safety valve installation port are provided in the product area.

4. The HPPO process propylene oxide reactor according to claim 1, wherein A flow meter and a regulating valve are respectively provided on the propylene pipeline and the alcohol-water pipeline.

5. A method for producing propylene oxide, characterized in that: The HPPO propylene oxide reactor according to any one of claims 1 to 4 is implemented, comprising the following steps: a. Filling the hollow tube of the reactor with a mixture of a catalyst and a solid catalyst substitute, filling the lower portion of the hollow tube with a catalyst volume content of 15-30% of the mixture to form a first filling layer, filling the middle portion of the hollow tube with a catalyst volume content of 45-55% of the mixture to form a second filling layer, and filling the upper portion of the hollow tube with a catalyst volume content of 15-25% of the mixture to form a third filling layer; b. Assembled to obtain HPPO propylene oxide reactor; c. The raw material propylene solution is input through the propylene pipeline, the raw material methanol and hydrogen peroxide solution are input through the alcohol-water pipeline, the raw material propylene solution is mixed with the raw material methanol and hydrogen peroxide solution and then enters the raw material area of ​​the reactor, and at the same time, a cold source is injected into the first reaction zone, the second reaction zone, and the third reaction zone through each cold source inlet; d. The mixed solution in the raw material zone flows upward and enters the hollow tube from the lower end of the hollow tube. With methanol as the solvent, propylene and hydrogen peroxide undergo propylene epoxidation reaction under the action of the catalyst to produce propylene oxide and water, which is discharged from the upper end of the hollow tube to the product zone to obtain a mixed solution containing propylene oxide, water, propylene, and methanol; e. The mixed solution containing propylene oxide, water, propylene and methanol is transported to the subsequent process through the discharge pipe; f. Start the ultrasonic transducer regularly to remove carbon deposits on the catalyst surface.

6. The method for producing propylene oxide according to claim 5, wherein The pressure in the reactor is controlled to be 2.4-2.8Mpa, and the reaction temperature in the first reaction zone, the second reaction zone, and the third reaction zone is controlled to be 45-60°C. The reaction temperature is controlled by adjusting the flow rate and flow velocity of the cold source in the first reaction zone, the second reaction zone, and the third reaction zone.

7. The method for producing propylene oxide according to claim 5, wherein The solid catalyst substitute is a glass ball or a glazed ceramic ball without catalytic and adsorption functions.

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