CN116328666A - Propylene oxide preparation device and preparation method - Google Patents
Propylene oxide preparation device and preparation method Download PDFInfo
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- CN116328666A CN116328666A CN202111604459.9A CN202111604459A CN116328666A CN 116328666 A CN116328666 A CN 116328666A CN 202111604459 A CN202111604459 A CN 202111604459A CN 116328666 A CN116328666 A CN 116328666A
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- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
- B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
- B01J8/24—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique
- B01J8/26—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique with two or more fluidised beds, e.g. reactor and regeneration installations
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D301/00—Preparation of oxiranes
- C07D301/02—Synthesis of the oxirane ring
- C07D301/03—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds
- C07D301/12—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with hydrogen peroxide or inorganic peroxides or peracids
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D303/00—Compounds containing three-membered rings having one oxygen atom as the only ring hetero atom
- C07D303/02—Compounds containing oxirane rings
- C07D303/04—Compounds containing oxirane rings containing only hydrogen and carbon atoms in addition to the ring oxygen atoms
Abstract
The invention particularly relates to a propylene oxide preparation device and a preparation method, and belongs to the technical field of fine chemical engineering. The utility model provides a propylene oxide preparation facilities, it includes tubular fluidized bed reactor, catalyst circulation mechanism and sedimentation separator, and sedimentation separator opens has product outlet, separation entry and catalyst export, and the export and the separation entry intercommunication of fluidized bed reactor, catalyst export and catalyst circulation mechanism's entry intercommunication, catalyst circulation mechanism's export and fluidized bed reactor's entry intercommunication, and the fluidized bed reactor is equipped with heat transfer mechanism along length direction. The method can solve the technical problems that the reaction heat cannot be effectively controlled and removed in the prior art, the temperature is unstable, and then the selectivity of propylene oxide is low.
Description
Technical Field
The invention belongs to the technical field of fine chemical engineering, and particularly relates to a propylene oxide preparation device and a preparation method.
Background
Propylene oxide is an important propylene derivative, is mainly used for producing polyether polyol, propylene glycol ether, isopropanolamine, propylene carbonate and the like, is one of main raw materials for manufacturing polyurethane, nonionic surfactant, emulsifying agent, oilfield demulsifier, flame retardant, plasticizer, lubricating oil and the like, and has wide application in industries such as petroleum, chemical industry, pesticide, textile, daily chemicals and the like.
Currently, the production methods of propylene oxide mainly include chlorohydrin method, co-oxidation method and hydrogen peroxide direct oxidation method (HPPO method). The three wastes discharge amount of the chlorohydrin method is large, the environmental pollution is serious, the comprehensive treatment difficulty is large, and the development of the chlorohydrin method is limited. The co-oxidation method is also called as 'Ha Kang Fa', and comprises an isobutane co-oxidation method and an ethylbenzene co-oxidation method, wherein isobutane or ethylbenzene and propylene are subjected to co-oxidation reaction to generate PO, and Tertiary Butyl Alcohol (TBA) or Styrene (SM) are co-produced.
In recent years, green environmental protection is the subject of advocacy in production and life, propylene and industrial hydrogen peroxide are taken as raw materials by an HPPO method, propylene oxide is directly oxidized under the catalysis of a titanium-silicon molecular sieve catalyst, the process flow is simple, the reaction condition is mild, no harmful gas is discharged in the whole production process, the generated sewage can reach the standard for discharge after general treatment, and the advantages of green environmental protection, low production cost and the like become one of the fastest-expanding and most promising processes at present. The foreign patent manufacturer having the technology is mainly the union of the German winning group and the Thysen Krupp group, and the union of the Basf company and the Daochi company, and the domestic autonomous research and development technology is in the key period of industrial application.
The HPPO has the key technical problems of high reaction heat release, limited catalyst mass transfer, influence on selectivity and improvement of catalyst life. At present, the industrialized HPPO process is realized by using methanol as a solvent and oxidizing propylene to synthesize propylene oxide under the action of a titanium-silicon molecular sieve in an axial fixed bed reactor, wherein the reaction is a strong exothermic reaction, the unit reaction heat is about 318kJ/mol, the reaction heat needs to be removed, otherwise, heat accumulation and hydrogen peroxide decomposition are easy, the explosion risk occurs, the reaction selectivity is poor, byproducts are more, meanwhile, the axial fixed bed materials are easy to be unevenly distributed, the phenomenon of 'flying temperature' is easy to occur in part of a catalyst layer, the service life of the catalyst is shortened, and the catalyst needs to be regenerated once every one to two months, so that the economic benefit of enterprises is seriously influenced.
Chinese patent CN107417645B discloses a method of using corrugated plates as a heat transfer plate group, using 4 series corrugated plate reactors, forcibly circulating the circulating cooling water to optimize heat removal and controlling the temperature of the circulating cooling water through a thermometer and a regulating valve to uniform the reaction temperature. Solves the problems of poor heat transfer effect and short service life of the catalyst existing in the traditional fixed bed reactor. However, the gaps among the corrugated plates of the plate reactor are small, and the catalyst is difficult to assemble and disassemble.
Chinese patent CN109999727a discloses a method for synthesizing propylene oxide with a tubular fixed bed reactor, which comprises: (1) A multi-layer titanium silicalite molecular sieve catalyst is filled in the tube side of the tube type fixed bed reactor, the multi-layer titanium silicalite molecular sieve catalyst is filled along the increasing direction of the skeleton titanium content, and the ratio of the n-1 layer titanium silicalite molecular sieve catalyst to the n layer titanium silicalite molecular sieve catalyst is 1:1.5-5; (2) And (3) conveying propylene, hydrogen peroxide, methanol and an auxiliary agent into the tubular fixed bed reactor, wherein the feeding direction is consistent with the increasing direction of the activity of the multilayer titanium-silicon molecular sieve catalyst, and collecting a reaction discharge port material after the reaction is finished. The invention has even heat release, and the temperature rise of the hot spot in the tube side is small. But adopts a plurality of types of catalysts for layered filling, the catalysts are filled in each pipeline, the filling operation requirement on the catalysts is high, and the catalysts are not easy to unload.
Chinese patent CN109180611a discloses a feeding and distributing device and method for preparing propylene oxide by hydrogen peroxide direct oxidation method with sectional injection of raw materials, wherein the process for preparing propylene oxide by hydrogen peroxide direct oxidation method adopts at least two groups of reaction units connected in series, and the raw materials are fed into each reaction unit in sections, so that the problem of uneven distribution of hydrogen peroxide in the reactor is solved, the conversion rate of hydrogen peroxide and the yield of propylene oxide are improved, and the potential safety hazard is reduced. The axial fixed bed reactors are adopted for each group of reactors, so that the problem of uniform distribution of materials can not be well solved.
Chinese patent CN104130216B discloses a process for continuously producing propylene oxide by directly oxidizing propylene/propane mixed gas with hydrogen peroxide. In the reaction process, a fluidized bed circulation reactor is adopted, a fine-particle molecular sieve catalyst is adopted, the slurry discharge is used for respectively steaming out low-oxygen propylene/propane mixed gas and epoxypropane through a flash tower, catalyst-containing mother liquor is used for separating catalyst slurry and mother liquor through a membrane separator, after methanol is separated through flash evaporation, the residual high-oxygen propylene/propane mixed gas after the recovery solvent methanol is synchronously recovered and reacted in a high-oxygen propylene/propane absorption tower is recycled, and the catalyst slurry is returned to the reactor for recycling after being partially regenerated on line. However, the reaction product and the reaction material of the circulating reactor in the patent are seriously mixed back, the reaction efficiency is low, and the side reaction is increased.
As is clear from the analysis, in the prior art, a fixed bed reactor is adopted, and the reaction heat is removed from the reactor by a method of enhancing heat exchange, so that the problems of uneven material distribution, lag in temperature control, easy local supercooling or overheating, low propylene oxide selectivity and the like still exist although the reaction heat is improved compared with the traditional tubular reactor, the operation period is short, and the reaction heat needs to be regenerated every 1500-2000 hours. In addition, complicated reactors or reaction units have problems such as high equipment investment, difficult catalyst loading or replacement, and the like.
Disclosure of Invention
The utility model aims at providing a propylene oxide preparation facilities solves prior art and can't effective control and remove the reaction heat, leads to the temperature unstable, leads to the low technical problem of propylene oxide selectivity then.
The embodiment of the invention provides a propylene oxide preparation device which comprises a tubular fluidized bed reactor, a catalyst circulating mechanism and a sedimentation separator, wherein the sedimentation separator is provided with a product outlet, a separation inlet and a catalyst outlet, the outlet of the fluidized bed reactor is communicated with the separation inlet, the catalyst outlet is communicated with the inlet of the catalyst circulating mechanism, the outlet of the catalyst circulating mechanism is communicated with the inlet of the fluidized bed reactor, and the fluidized bed reactor is provided with a heat exchange mechanism along the length direction.
Optionally, the catalyst circulation mechanism includes regenerator and circulation riser, the sedimentation separator includes the knockout drum, and the product export is offered at the knockout drum top, and the separation entry is offered to the knockout drum bottom, and the catalyst export of tea pot mouth formula is offered to the knockout drum lower part lateral wall, the circulation riser is U type pipe, the exit end of fluidized bed reactor stretches into in the knockout drum through the separation entry, the catalyst export communicates with the entry of regenerator, and the export of regenerator communicates with the entry way of circulation riser, and the export of circulation riser communicates with the entry of fluidized bed reactor.
Optionally, the inlet of the circulating lifter is communicated with a lock hopper, the inlet of the lock hopper is communicated with the outlet of the regenerator, the inlet of the regenerator is communicated with the catalyst outlet through a circulating pipe, and the lock hopper is provided with a catalyst adding port.
Optionally, the circulation tube is in communication with the inlet of the lock hopper via a bypass tube.
Optionally, the circulation pipe is provided with a flow valve.
Optionally, the inlet end of the fluidized bed reactor is provided with a venturi-type distributor, the inlet end of the venturi-type distributor is provided with a micro-pore dispersing device, the micro-pore dispersing device is provided with a plurality of micro-pore channels, and the outlet of the circulating lifter is communicated with the feed inlet of the venturi-type distributor.
Optionally, a distributor is arranged at the outlet end of the fluidized bed reactor.
The embodiment of the invention also provides a propylene oxide preparation method, which adopts any one of the propylene oxide preparation devices to prepare, and comprises the following steps:
hydrogen peroxide and propylene are used as raw materials, and methanol is used as a solvent to be introduced into an inlet of the fluidized bed reactor;
introducing catalyst particles into an inlet of a fluidized bed reactor by using the catalyst circulating mechanism, and converging with the raw materials;
the raw materials react in the fluidized bed reactor under the reaction condition;
the heat of reaction is absorbed by the heat exchange mechanism in the reaction process;
obtaining a reaction mixture containing a catalyst in the sedimentation separator;
separating the reaction mixture containing the catalyst by using a sedimentation separator, obtaining a reaction product containing propylene oxide at the product outlet, and obtaining a concentrated slurry of catalyst particles at the catalyst outlet;
refluxing the concentrated slurry of catalyst particles with the catalyst circulation mechanism;
wherein the reaction conditions include: the reaction flow rate is 0.06-0.5m/s; the reaction temperature is 30-80 ℃; the reaction pressure is 0.6-2.5MPa; the mass airspeed of hydrogen peroxide is 0.1-10.0hr -1 The method comprises the steps of carrying out a first treatment on the surface of the The mol ratio of propylene to hydrogen peroxide is (1.2-3) 1; the molar ratio of the methanol to the hydrogen peroxide is (2.0-10): 1.
Optionally, the method further comprises the following steps:
the circulating pipe and the bypass pipe are utilized to shunt the concentrated slurry of the catalyst particles, and slurry to be regenerated is obtained in the circulating pipe;
regenerating the slurry to be regenerated with the regenerator;
wherein: the mass of the slurry to be regenerated is 5-30wt% of the mass of the concentrated slurry of the catalyst particles.
Optionally, the catalyst particles are titanium silicalite HPPO catalyst, and the diameter of the catalyst particles is 0.2-1.6mm.
One or more technical solutions in the embodiments of the present invention at least have the following technical effects or advantages:
the propylene oxide preparation device comprises a tubular fluidized bed reactor, a catalyst circulation mechanism and a sedimentation separator, wherein the sedimentation separator is provided with a product outlet, a separation inlet and a catalyst outlet, the outlet of the fluidized bed reactor is communicated with the separation inlet, the catalyst outlet is communicated with the inlet of the catalyst circulation mechanism, the outlet of the catalyst circulation mechanism is communicated with the inlet of the fluidized bed reactor, and the fluidized bed reactor is provided with a heat exchange mechanism along the length direction. The fluidized bed reactor is arranged, raw materials and a catalyst are converged and introduced into the fluidized bed reactor for reaction, the raw materials and the catalyst flow along the length direction of the fluidized bed reactor together during the reaction, the problem that the local temperature of the contact part of the raw materials and the catalyst is instantaneously increased due to the fixed arrangement of the catalyst, the reaction temperature is uncontrollable and even hot spots are generated is avoided, the problem of low propylene oxide selectivity is avoided, and the reaction heat generated by the reaction is uniformly dispersed in the liquid flow of the raw materials and the catalyst; meanwhile, the heat exchange mechanism is arranged on the fluidized bed reactor along the length direction, so that reaction heat is absorbed in time, and as liquid flow flows along the length direction of the fluidized bed reactor as well, the liquid flow contacts the heat exchange mechanism to exchange heat and flows relatively, the heat absorption effect of the heat exchange mechanism is effectively improved, and the reaction temperature is effectively controlled and processed. The settling separator is arranged, so that a reaction mixture containing the catalyst produced in the fluidized bed reactor is separated into propylene oxide and concentrated slurry of catalyst particles, and the catalyst is enriched while the product is obtained; by arranging the catalyst circulating mechanism, the enriched catalyst is mixed with the raw materials again to realize continuous flow of the catalyst.
The foregoing description is only an overview of the present invention, and is intended to be implemented in accordance with the teachings of the present invention in order that the same may be more clearly understood and to make the same and other objects, features and advantages of the present invention more readily apparent.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic view of an apparatus for producing propylene oxide according to an embodiment of the present invention;
fig. 2 is a flow chart of a propylene oxide preparation method provided in an embodiment of the present invention.
Reference numerals: 10-a fluidized bed reactor; 11-a heat exchange mechanism; 12-a distributor; 13-a micro-channel dispersing device; a 20-regenerator; 201-a circulation tube; 202-bypass pipe; 203-a flow valve; 21-a sedimentation separator; 211-a separation tank; 2111-product outlet; 2112-separation inlet; 2113-catalyst outlet; 22-cycle lifter; 23-lock hopper; 231-catalyst addition port.
Detailed Description
The advantages and various effects of the present invention will be more clearly apparent from the following detailed description and examples. It will be understood by those skilled in the art that these specific embodiments and examples are intended to illustrate the invention, not to limit the invention.
Throughout the specification, unless specifically indicated otherwise, the terms used herein should be understood as meaning as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification will control. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the scope of the present invention. For example, room temperature may refer to a temperature in the range of 10 to 35 ℃.
Unless otherwise specifically indicated, the various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or may be prepared by existing methods.
The technical scheme of the embodiment of the application aims to solve the technical problems, and the overall thought is as follows:
referring to fig. 1, according to an exemplary embodiment of the present invention, there is provided a propylene oxide production apparatus, which includes a fluidized bed reactor 10 having a tubular shape, a catalyst circulation mechanism, and a sedimentation separator 21, wherein the sedimentation separator 21 is provided with a product outlet 2111, a separation inlet 2112, and a catalyst outlet 2113, the outlet of the fluidized bed reactor 10 is communicated with the separation inlet 2112, the catalyst outlet 2113 is communicated with the inlet of the catalyst circulation mechanism, the outlet of the catalyst circulation mechanism is communicated with the inlet of the fluidized bed reactor 10, and the fluidized bed reactor 10 is provided with a heat exchange mechanism 11 along a length direction. By arranging the fluidized bed reactor 10, the raw materials and the catalyst are converged and introduced into the fluidized bed reactor 10 for reaction, and the raw materials and the catalyst flow along the length direction of the fluidized bed reactor 10 together during the reaction, so that the problem that the reaction temperature is uncontrollable and even hot spots are generated due to the fact that the local temperature of the contact part of the raw materials and the catalyst is instantaneously increased due to the fixed arrangement of the catalyst is avoided, and the problem that the selectivity of propylene oxide is low is avoided, and the reaction heat generated by the reaction is uniformly dispersed in the liquid flow of the raw materials and the catalyst; meanwhile, the heat exchange mechanism 11 is arranged on the fluidized bed reactor 10 along the length direction, so that reaction heat is absorbed in time, and as liquid flow flows along the length direction of the fluidized bed reactor 10 as well, the liquid flow contacts the heat exchange mechanism 11 to exchange heat and flows relatively, the heat absorption effect of the heat exchange mechanism 11 is effectively improved, and the reaction temperature is effectively controlled and processed. By providing the sedimentation separator 21, the reaction mixture containing the catalyst produced in the fluidized bed reactor 10 is separated into propylene oxide and concentrated slurry of catalyst particles by using the sedimentation separator, and the product is obtained and the catalyst is enriched at the same time; by arranging the catalyst circulating mechanism, the enriched catalyst is mixed with the raw materials again to realize continuous flow of the catalyst.
The heat exchange means 11 is any one of the prior art, and is preferably a cooling jacket provided outside the fluidized bed reactor 10 or a cooling pipe or a plate cooler provided inside the fluidized bed reactor 10.
In some embodiments, the catalyst circulation mechanism comprises a regenerator 20 and a circulation lifter 22, the sedimentation separator 21 comprises a separation tank 211, a product outlet 2111 is formed in the top of the separation tank 211, a separation inlet 2112 is formed in the bottom of the separation tank 211, a teapot-mouth-shaped catalyst outlet 2113 is formed in the side wall of the lower part of the separation tank 211, the circulation lifter 22 is a U-shaped pipe, the outlet end of the fluidized bed reactor 10 extends into the separation tank 211 through the separation inlet 2112, the catalyst outlet 2113 is communicated with the inlet of the regenerator 20, the outlet of the regenerator 20 is communicated with the inlet path of the circulation lifter 22, and the outlet of the circulation lifter 22 is communicated with the inlet of the fluidized bed reactor 10. By providing the sedimentation separator 21 comprising the separation tank 211 with the product outlet 2111 at the top and the separation inlet at the bottom and the catalyst outlet 2113 of the tea-pot mouth at the lower side wall, and making the outlet end of the fluidized bed reactor 10 extend into the separation tank 211 through the separation inlet 2112 (seal), firstly, the reaction mixture of the product of the fluidized bed reactor 10 containing the catalyst is accumulated in the separation tank 211, then the liquid propylene oxide flows out from the product outlet 2111, and the concentrated slurry of the catalyst particles is enriched at the bottom of the separation tank 211 under the action of gravity and then is separated and discharged through the catalyst outlet 2113, and since the outlet end of the fluidized bed reactor 10 extends into the separation tank 211 through the separation inlet 2112 (seal), the back mixing of the propylene oxide product or the concentrated slurry of the catalyst can be effectively avoided. The catalyst circulation mechanism comprises a regenerator 20 and a circulation lifter 22, the regenerator 20 is utilized to regenerate the concentrated slurry of catalyst particles, the activity and the selectivity of the catalyst are maintained, the circulation lifter 22 is arranged, and the catalyst circulation mechanism is provided with a U-shaped pipe and a lifting pipeline (not shown), so that the catalyst circulation and the flow control are realized.
In some embodiments, the inlet of the recycle riser 22 is in communication with a lock hopper 23, the inlet of the lock hopper 23 is in communication with the outlet of the regenerator 20, the inlet of the regenerator 20 is in communication with the catalyst outlet 2113 through the recycle pipe 201, and the lock hopper 23 is provided with a catalyst addition port 231. By providing the lock hopper 23, the catalyst is collected while controlling the flow rate of the catalyst, by providing the catalyst addition port 231 thereon for replenishing the catalyst at any time, and at the same time, it is also provided with a catalyst take-out port for replacing the deactivated catalyst therein.
In some embodiments, the circulation tube 201 communicates with the inlet of lock hopper 23 via bypass tube 202. By arranging the circulating pipe 201 and the bypass pipe 202, the catalyst particle thick slurry is split, only a part of catalyst particle thick slurry flows into the regenerator 20 for regeneration, and after few reactions, only part of catalyst is deactivated and only part of catalyst is periodically regenerated, so that the condition that all the catalyst is introduced into the regenerator 20 to cause excessive load of the regenerator 20 is effectively avoided.
In some embodiments, the circulation tube 201 is equipped with a flow valve 203. By providing the flow valve 203, the proportion of the catalyst particle concentrated slurry obtained by the diversion of the circulation pipe 201 can be effectively controlled, so that the catalyst particle concentrated slurry can be accurately and effectively regulated and controlled according to actual conditions.
In some embodiments, the inlet end of the fluidized bed reactor 10 is provided with a venturi-type distributor, the inlet end of the venturi-type distributor is provided with a micro-pore dispersing device 13, the micro-pore dispersing device 13 is provided with a plurality of micro-pore channels, and the outlet of the circulating lifter 22 is communicated with the feed inlet of the venturi-type distributor. The inlet end of the fluidized bed reactor 10 is provided with the Venturi distributor, so that raw materials can be sprayed into the fluidized bed reactor 10, and the raw materials are effectively dispersed to form micro-droplets by arranging the micro-channel dispersing device 13, so that the mass transfer area is greatly increased, the residence time is effectively premixed, the reaction pressure is reduced, and the energy consumption is reduced.
In some embodiments, the outlet end of the fluidized bed reactor 10 is provided with a distributor 12. The distributor 12 is used for ensuring that the fluid bed reactor 10 is internally provided with plug flow, the catalyst and the raw materials are uniformly mixed slurry, no back mixing is caused, and the reaction product and the catalyst are easy to separate.
According to another exemplary embodiment of the present invention, there is also provided a propylene oxide production method using any one of the propylene oxide production apparatuses described above, including the steps of:
s1, hydrogen peroxide and propylene are used as raw materials, and methanol is used as a solvent to be introduced into an inlet of the fluidized bed reactor 10.
And S2, introducing catalyst particles into an inlet of the fluidized bed reactor 10 by using the catalyst circulating mechanism, and converging the catalyst particles with the raw materials.
S3, the raw materials react in the fluidized bed reactor 10 under the reaction condition.
S4, the heat of reaction is absorbed by the heat exchange mechanism 11 in the reaction process.
S5, obtaining a reaction mixture containing the catalyst in the sedimentation separator 21.
S6, separating the reaction mixture containing the catalyst by using a sedimentation separator 21, obtaining a reaction product containing propylene oxide at the product outlet 2111, and obtaining a concentrated slurry of catalyst particles at the catalyst outlet 2113.
S7, refluxing the thick slurry of the catalyst particles by using the catalyst circulating mechanism.
Wherein the concentration of the hydrogen peroxide is 27.5-70wt%; the reaction conditions include: the reaction flow rate is 0.06-0.5m/s; the reaction temperature is 30-80 ℃; the reaction pressure is 0.6-2.5MPa; the mass airspeed of hydrogen peroxide is 0.1-10.0hr -1 The method comprises the steps of carrying out a first treatment on the surface of the The mol ratio of propylene to hydrogen peroxide is (1.2-3) 1; the molar ratio of the methanol to the hydrogen peroxide is (2.0-10): 1.
Preferably, the reaction flow rate is from 0.1 to 0.3m/s; the reaction temperature is 35-50 ℃; the reaction pressure is 1.6-2.0MPa; the mass airspeed of hydrogen peroxide is 1.0-5.0hr -1 The method comprises the steps of carrying out a first treatment on the surface of the The mol ratio of propylene to hydrogen peroxide is (1.2-1.5): 1; the molar ratio of the methanol to the hydrogen peroxide is (4-6) 1.
In some embodiments, the method further comprises the steps of:
s6.1, the circulating pipe 201 and the bypass pipe 202 are utilized to split the concentrated slurry of the catalyst particles, and the slurry to be regenerated is obtained in the circulating pipe 201.
S6.2 regenerating the slurry to be regenerated using the regenerator 20.
Wherein: the mass of the slurry to be regenerated is 5-30wt%, preferably 10-20wt% of the mass of the concentrated slurry of the catalyst particles.
In some embodiments, the catalyst particles are titanium silicalite HPPO catalysts, the catalyst particles having a diameter of 0.2 to 1.6mm, preferably 0.5 to 1.0mm.
The following will explain the embodiments of the present application in detail with reference to examples, comparative examples and experimental data.
Example 1
The embodiment provides a preparation method of propylene oxide, which comprises the following steps:
s1, hydrogen peroxide and propylene are used as raw materials, and methanol is used as a solvent to be introduced into an inlet of the fluidized bed reactor 10.
And S2, introducing catalyst particles into an inlet of the fluidized bed reactor 10 by using the catalyst circulating mechanism, and converging the catalyst particles with the raw materials.
S3, the raw materials react in the fluidized bed reactor 10 under the reaction condition.
S4, the heat of reaction is absorbed by the heat exchange mechanism 11 in the reaction process.
S5, obtaining a reaction mixture containing the catalyst in the sedimentation separator 21.
S6, separating the reaction mixture containing the catalyst by using a sedimentation separator 21, obtaining a reaction product containing propylene oxide at the product outlet 2111, and obtaining a concentrated slurry of catalyst particles at the catalyst outlet 2113.
S6.1, the circulating pipe 201 and the bypass pipe 202 are utilized to split the concentrated slurry of the catalyst particles, and the slurry to be regenerated is obtained in the circulating pipe 201.
S6.2 regenerating the slurry to be regenerated using the regenerator 20.
S7, refluxing the thick slurry of the catalyst particles by using the catalyst circulating mechanism.
Wherein the fluidized bed reactor 10 has a diameter of 50mm and a height (length) of 12m; the concentration of hydrogen peroxide is 50wt percent, and the volume content of propylene is 99 percent; the catalyst particles are TS-1 type titanium silicalite HPPO catalyst. The reaction conditions include: the reaction flow rate is 0.1m/s; the reaction temperature is 35 ℃; the reaction pressure is 2.0MPa; the mol ratio of hydrogen peroxide to propylene to methanol is 1:1.5:4, a step of; the catalyst circulation amount was 15kg/h.
Example 2
This example provides a propylene oxide production process differing from example 1 only in that: the reaction flow rate was 0.25m/s.
Example 3
This example provides a propylene oxide production process differing from example 1 only in that: the mol ratio of hydrogen peroxide to propylene to methanol is 1:1.5:2.
example 4
This example provides a propylene oxide production process differing from example 1 only in that: the concentration of hydrogen peroxide is 27.5wt%.
Example 5
This example provides a propylene oxide production process differing from example 4 only in that: the catalyst circulation amount was 20kg/h.
Comparative example 1
Chinese patent CN109999727a, which synthesizes propylene oxide by using a tubular fixed bed reactor, wherein a tube side of the tubular fixed bed reactor is filled with a multi-layer titanium silicalite molecular sieve catalyst, and propylene, hydrogen peroxide, methanol and an auxiliary agent are fed into the tubular fixed bed reactor. Comparing examples 1-4 of this patent publication, the best results among them were chosen as comparative example 1.
Comparative example 2
Chinese patent CN109180611a, which uses a two-stage tube fixed bed reactor, selected the effect disclosed in this patent as comparative example 2.
Comparative example 3
Chinese patent CN104130216B, which is a process for continuously producing propylene oxide by directly oxidizing propylene/propane mixed gas with hydrogen peroxide, adopts a fluidized bed loop reactor in the reaction procedure, and selects the best implementation effect disclosed in the patent as comparative example 3.
Experimental example 1
The preparation was carried out according to the propylene oxide preparation methods of examples 1 to 5 and comparative examples 1 to 3, and after the reaction was completed, the conversion of hydrogen peroxide and the selectivity of propylene oxide were calculated, and the calculation results are shown in Table 1.
TABLE 1
| Hydrogen peroxide conversion rate% | Propylene oxide selectivity% | Reaction temperature rise DEG C | |
| Example 1 | 99.8 | 99.7 | 1.5 |
| Example 2 | 99.7 | 99.8 | 1.0 |
| Example 3 | 99.9 | 99.7 | 3.0 |
| Example 4 | 99.6 | 99.9 | 1.0 |
| Example 5 | 99.9 | 99.8 | 1.2 |
| Comparative example 1 | 99.3 | 98 | 6 |
| Comparative example 2 | 98.8 | 98.2 | - |
| Comparative example 3 | 95 | 99 | - |
As can be seen from Table 1, according to the comparison of examples 1-5 and comparative examples 1-3, the conversion rate of hydrogen peroxide in the propylene oxide preparation device and the preparation method provided by the invention is far higher than that in the prior art, the conversion rate of hydrogen peroxide is more than or equal to 99.6%, the reaction temperature rise is effectively controlled to be less than or equal to 3 ℃, the continuous production operation can be realized, and the selectivity of propylene oxide is effectively ensured, wherein the selectivity is more than or equal to 99.7%.
One or more technical solutions in the embodiments of the present invention at least have the following technical effects or advantages:
(1) The propylene oxide preparation device provided by the embodiment of the invention realizes continuous and stable operation of propylene epoxidation reaction and deactivated catalyst regeneration, effectively maintains the balance activity of the catalyst, improves the selectivity of target products, and greatly improves the operation and operation period and economy of the device.
(2) The propylene oxide preparation device provided by the embodiment of the invention adopts the fluidized bed reactor, ensures that the reaction materials are pushed forward horizontally, has uniform reaction temperature and no hot spot, greatly inhibits side reaction, and has high reaction conversion rate and product selectivity and long service life of the catalyst.
(3) According to the propylene oxide preparation device provided by the embodiment of the invention, the micro-pore dispersion device is arranged to disperse hydrogen peroxide into micro-droplets, so that the mass transfer area of a micro-interface is large, the reaction residence time is long, the contact time of reaction materials and a catalyst is short, and the occurrence of side reactions is effectively inhibited.
(4) According to the propylene oxide preparation device provided by the embodiment of the invention, the circulating pipe and the bypass pipe are arranged to shunt the catalyst, so that the catalyst is only partially regenerated, the consumption of regeneration medium is low, the device can be recycled, and the energy consumption of the device is low.
(5) According to the propylene oxide preparation device provided by the embodiment of the invention, the circulating lifter is a U-shaped pipe, so that the catalyst is flexible to control in a circulating way and has small catalyst abrasion.
(6) According to the propylene oxide preparation device provided by the embodiment of the invention, the pressure between the regenerator and the fluidized bed reactor is adjusted by arranging the lock hopper, so that the catalyst is guided to be circularly conveyed, and the operation of the catalyst system is stable and controllable.
(7) According to the propylene oxide preparation method provided by the embodiment of the invention, the conversion rate of hydrogen peroxide is more than or equal to 99.6%, the reaction temperature rise is effectively controlled to be less than or equal to 3 ℃, continuous production operation can be realized, and the selectivity of propylene oxide is effectively ensured, wherein the selectivity is more than or equal to 99.7%.
Finally, it is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
Claims (10)
1. A propylene oxide preparation device is characterized by comprising a tubular fluidized bed reactor (10), a catalyst circulating mechanism and a sedimentation separator (21), wherein the sedimentation separator (21) is provided with a product outlet (2111), a separation inlet (2112) and a catalyst outlet (2113),
the outlet of the fluidized bed reactor (10) is communicated with a separation inlet (2112),
the catalyst outlet (2113) communicates with the inlet of the catalyst circulation mechanism,
the outlet of the catalyst circulation mechanism is communicated with the inlet of the fluidized bed reactor (10),
the fluidized bed reactor (10) is provided with a heat exchange mechanism (11) along the length direction.
2. The propylene oxide production apparatus according to claim 1, wherein the catalyst circulation mechanism comprises a regenerator (20) and a circulation riser (22),
the sedimentation separator (21) comprises a separating tank (211), a product outlet (2111) is formed in the top of the separating tank (211), a separating inlet (2112) is formed in the bottom of the separating tank (211), a catalyst outlet (2113) of a tea pot nozzle type is formed in the side wall of the lower part of the separating tank (211), the circulating lifter (22) is a U-shaped pipe,
the outlet end of the fluidized bed reactor (10) extends into the separation tank (211) through the separation inlet (2112), the catalyst outlet (2113) is communicated with the inlet of the regenerator (20), the outlet of the regenerator (20) is communicated with the inlet path of the circulating lifter (22), and the outlet of the circulating lifter (22) is communicated with the inlet of the fluidized bed reactor (10).
3. Propylene oxide production plant according to claim 2, characterized in that the inlet of the circulation riser (22) is connected with a lock hopper (23), the inlet of the lock hopper (23) is connected with the outlet of the regenerator (20), the inlet of the regenerator (20) is connected with the catalyst outlet (2113) through a circulation pipe (201), and the lock hopper (23) is provided with a catalyst addition port (231).
4. A propylene oxide production plant according to claim 3, characterized in that the circulation pipe (201) communicates with the inlet of the lock hopper (23) through a bypass pipe (202).
5. Propylene oxide production apparatus according to claim 4, characterized in that the circulation pipe (201) is equipped with a flow valve (203).
6. Propylene oxide production apparatus according to claim 2, characterized in that the inlet end of the fluidized bed reactor (10) is provided with a venturi-type distributor, the inlet end of the venturi-type distributor is provided with a micro-channel dispersion device (13), the micro-channel dispersion device (13) is provided with a plurality of micro-channel channels, and the outlet of the circulating lifter (22) is communicated with the feed inlet of the venturi-type distributor.
7. Propylene oxide production plant according to claim 1, characterized in that the outlet end of the fluidized bed reactor (10) is provided with a distributor (12).
8. A method for producing propylene oxide, characterized by using the propylene oxide production apparatus according to any one of claims 1 to 7, comprising the steps of:
hydrogen peroxide and propylene are used as raw materials, and methanol is used as a solvent to be introduced into an inlet of the fluidized bed reactor (10);
introducing catalyst particles into an inlet of a fluidized bed reactor (10) by using the catalyst circulating mechanism, and converging with the raw materials;
the raw materials react in the fluidized bed reactor (10) under the reaction condition;
the heat of reaction is absorbed by the heat exchange mechanism (11) in the reaction process;
obtaining a reaction mixture containing catalyst in the sedimentation separator (21);
separating the catalyst-containing reaction mixture using a settling separator (21) to obtain a propylene oxide-containing reaction product at the product outlet (2111) and a concentrated slurry of catalyst particles at the catalyst outlet (2113);
refluxing the concentrated slurry of catalyst particles with the catalyst circulation mechanism;
wherein the reaction conditions include:
the reaction flow rate is 0.06-0.5m/s;
the reaction temperature is 30-80 ℃;
the reaction pressure is 0.6-2.5MPa;
the mass airspeed of hydrogen peroxide is 0.1-10.0hr -1 ；
The mol ratio of propylene to hydrogen peroxide is (1.2-3) 1;
the molar ratio of the methanol to the hydrogen peroxide is (2.0-10): 1.
9. The method for producing propylene oxide according to claim 8, further comprising the steps of:
the circulating pipe (201) and the bypass pipe (202) are utilized to shunt the concentrated slurry of the catalyst particles, and slurry to be regenerated is obtained in the circulating pipe (201);
regenerating the slurry to be regenerated with the regenerator (20);
wherein:
the mass of the slurry to be regenerated is 5-30wt% of the mass of the concentrated slurry of the catalyst particles.
10. The method for producing propylene oxide according to claim 8, wherein the catalyst particles are titanium silicalite HPPO catalyst, and the diameter of the catalyst particles is 0.2 to 1.6mm.
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| CN117466839A (en) * | 2023-10-07 | 2024-01-30 | 中建安装集团有限公司 | Process for preparing propylene oxide by directly oxidizing propylene with hydrogen peroxide by using flat-plate membrane reactor |
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| CN117466839A (en) * | 2023-10-07 | 2024-01-30 | 中建安装集团有限公司 | Process for preparing propylene oxide by directly oxidizing propylene with hydrogen peroxide by using flat-plate membrane reactor |
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