Gas distribution unit, and bubble column reactor and reaction method using same

Abstract

The present invention relates to a gas distribution unit, and a bubble column reactor and a reaction method. The gas distribution unit of the present invention comprises at least one gas distribution pipe. The at least one gas distribution pipe comprises at least one gas outlet A and at least one gas outlet B from top to bottom, wherein the gas outlet A ejects gas downwards and to the side at an ejection angle εA, and the gas outlet B ejects gas downwards and to the side at an ejection angle εB, an ejection angle being the included angle between the direction of gas ejection and the vertical direction, εA>εB. The gas distribution unit of the present invention enables a more uniform distribution of gas and liquid raw materials, and a longer duration of contact for the gas and liquid raw materials. Using the present gas distribution unit in a bubble column reactor can effectively improve the conversion rate and selectivity of the reaction in said reactor, and can also avoid excessive local concentration of raw materials, thereby avoiding violent reactions and catalyst deactivation.

Description

Gas distribution unit, bubbling bed reactor and reaction method using the same Technical Field

[0001] The present invention relates to the technical field of heterogeneous reactions, and in particular to a gas distribution unit, a bubbling bed reactor using the unit, and a reaction method. Background Art

[0002] Bubble bed reactors are widely used for gas-liquid reactions and gas-liquid-solid reactions. Examples of gas-liquid reactions carried out using a bubble bed reactor include the reaction of preparing terephthalic acid (TA) from p-xylene (PX), formaldehyde carbonylation reaction, and the reaction of producing o- and p-halobenzaldehyde using halogenated toluene selective oxidation. Examples of gas-liquid-solid reactions carried out using a bubble bed reactor include residual oil hydrogenation, Fischer-Tropsch synthesis, ethylene carbonate, propylene carbonate, and butylene carbonate synthesis. The main production methods of ethylene carbonate include phosgene process, transesterification process, urea alcoholysis process, and addition process. The addition process includes feeding carbon dioxide gas into a bubble bed reactor, reacting with the ethylene oxide liquid feed in the reactor in the presence of a catalyst bed formed by catalyst particles to form ethylene carbonate.

[0003] For bubbling bed reactors, how to improve the contact time and uniformity of bubbles in the liquid phase is a problem of general concern in the industry. Chinese patent application CN106475017A discloses a gas-liquid-solid three-phase reactor for synthesizing ethylene carbonate from ethylene oxide and carbon dioxide, which includes, from bottom to top, a liquid discharge port, a liquid baffle, a gas feed port, a gas inlet distributor, a catalyst lower support sieve plate, a lower porcelain ball layer, a catalyst layer, an upper porcelain ball layer, a catalyst upper support sieve plate, a liquid feed port, a liquid feed distributor and a gas discharge port. Gas and liquid feeds enter the catalyst bed radially and uniformly through the gas distributor and the liquid distributor respectively. The catalyst bed is fixed in the reactor by upper and lower porcelain balls and upper and lower support sieve plates. Multiple sets of baffles are set at the bottom of the reactor, and overflow weirs are set on both sides. This solution achieves better separation of gas and liquid through the overflow weir. However, the presence of the overflow weir increases the liquid flow resistance, and the gas operating flux is small, which limits the production capacity of the reactor. In addition, the gas in the bed cannot be evenly distributed, which reduces the conversion rate and selectivity of the reactor. It is also easy for the local concentration of the gas-liquid-solid three-phase to be too high, the reaction to be highly exothermic, and then the catalyst to be deactivated.

[0004] Therefore, there has always been a demand for modifying the bubbling bed reactor to make the gas-liquid contact time longer and the distribution more uniform, so that higher conversion rate and selectivity can be achieved when using the bubbling bed reactor in the reaction, and catalyst deactivation can be effectively avoided.

[0005] Summary of the Invention

[0006] In order to overcome the problems existing in the prior art, the object of the present invention is to provide a gas distribution unit, a bubbling bed reactor and a reaction method. By controlling the gas injection angle of the gas outlet and optionally controlling the structure of the catalyst layer, the gas distribution unit of the present invention can make the gas-liquid raw material distribution more uniform and the gas-liquid raw material contact time longer. When the gas distribution unit is used in a bubbling bed reactor, it not only effectively improves the conversion rate and selectivity of the reaction in the reactor, but also can avoid the occurrence of excessive local concentration of raw materials, thereby avoiding violent reactions and catalyst deactivation.

[0007] To achieve the above-mentioned purpose, according to the first aspect of the present invention, the present invention provides a gas distribution unit, which includes at least one gas distribution pipe, and the at least one gas distribution pipe includes at least one gas outlet A and at least one gas outlet B from top to bottom, wherein the gas outlet A sprays gas downward at an injection angle εA, and the gas outlet B sprays gas downward at an injection angle εB, wherein the injection angle is the angle between the gas injection direction and the vertical direction, and εA>εB.

[0008] According to a second aspect of the present invention, the present invention provides a bubbling bed reactor comprising the gas distribution unit according to the first aspect.

[0009] According to a third aspect of the present invention, the present invention provides a reaction method, comprising the steps of: using the gas distribution unit according to the first aspect to inject gaseous reactants into a bubbling bed reactor to react with liquid reactants therein.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] 1) The present invention controls the gas outlet in the gas distribution unit to inject the gas obliquely downward into the bubbling bed reactor. The gas entering the reactor moves obliquely downward and, under the action of buoyancy, turns upward. The turning movement of the gas entering the reactor allows the bubbles to stay in the liquid feed longer, promoting gas-liquid mass transfer and facilitating the reaction. In addition, the turning movement of the gas entering the reactor increases the turbulence of the liquid phase. This also promotes gas-liquid mass transfer and facilitates the reaction.

[0012] 2) The present invention provides a gas outlet in the gas distribution unit so that the gas outlet injects the gas obliquely downward into the bubbling bed reactor from bottom to top at an increased injection angle. A larger injection angle means that the downward movement component of the gas entering the reactor is smaller. Unreacted gas feed will accumulate as the height increases. In the structure of the present invention, the downward velocity component of the gas injected into the reactor from the higher gas outlet is smaller. This can match the accumulation of unreacted gas feed, so that the gas feed is evenly distributed in the liquid feed throughout the bubbling bed reactor. This improves the conversion rate and selectivity of the reaction carried out therein;

[0013] 3) In a preferred embodiment, at least three gas outlets are provided from top to bottom, and the injection angles of the gas injected therefrom are controlled so that the injection angles decrease sequentially from top to bottom, and the reduction amplitude of the injection angles of two adjacent gas outlets increases sequentially from top to bottom. Unreacted gas feed will accumulate as the height increases. Correspondingly, the configuration of the present invention reduces the downward velocity component of the gas entering the reactor in an increasing manner from bottom to top, so that the gas feed is more evenly distributed in the liquid feed throughout the bubbling bed reactor. This further improves the conversion rate and selectivity of the reaction carried out therein;

[0014] 4) In a preferred embodiment, gas distributors at different heights are staggered. This further increases the turbulence of the gas and liquid, promotes mixing, and improves the conversion rate and selectivity of the reaction.

[0015] 5) In a preferred embodiment, at least one catalyst bed, preferably at least two catalyst beds, may be provided in the bubbling bed reactor, and a bottom gas distributor may be provided below each catalyst bed. This configuration can increase the probability of preventing back-mixing of catalysts in the two catalyst beds;

[0016] 6) In a preferred embodiment, the present invention provides at least one catalyst bed within a bubbling bed reactor, preferably with at least one gas distributor of the present invention installed within each catalyst bed. This configuration can enhance uniform gas distribution, increase contact between the feed and the catalyst, and improve reaction rate, conversion, and selectivity.

[0017] 7) In a preferred embodiment, at least two catalyst beds are provided, and the bed at a higher position in the bubbling bed reactor comprises catalyst particles with a larger average particle size, while the bed at a lower position in the bubbling bed reactor comprises catalyst particles with a smaller average particle size. On the one hand, since the diffusion path of the reactant in the catalyst particles with a smaller average particle size is shorter, and the specific surface area of ​​the catalyst particles with a smaller average particle size is larger, the reaction efficiency of the reactant on the catalyst particles with a smaller average particle size is higher. Accordingly, the catalyst bed at a lower position in the bubbling bed reactor comprises catalyst particles with a smaller average particle size, which allows more gaseous reactants to react, and less unreacted gaseous reactants rise along the reactor and leave the reactor. On the other hand, the settling velocity of the catalyst particles with a larger average particle size in the liquid is larger, and the reaction efficiency of the reactant thereon is lower. As described above, a plurality of gas outlets are provided at the different heights of the bubbling bed reactor, and the injection angle of the injected gas is reduced successively from top to bottom, preferably reducing the injection angle in a manner that increases with amplitude from top to bottom. This structure gradually increases the horizontal velocity component of the gas entering the reactor from bottom to top, which increases the turbulence of the liquid phase and catalyst particles, thereby offsetting the adverse effects of a larger average particle size on reaction efficiency. The structure of the catalyst layer and the gas distributor can produce a synergistic effect, further improving the conversion rate and selectivity of the reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG1 is a schematic structural diagram of a bubbling bed reactor according to one embodiment of the present invention.

[0019] FIG2 is a schematic structural diagram of a gas distributor according to an embodiment of the present invention.

[0020] FIG3 is a schematic cross-sectional view of a gas distribution pipe according to an embodiment of the present invention.

[0021] FIG4 is a schematic structural diagram of a bubbling bed reactor according to an embodiment of the present invention.

[0022] Explanation of the main figure marks: 1-bubbling bed reactor, 11-catalyst bed, 11A-upper catalyst bed, 11B-lower catalyst bed, 12A-first gas distributor, 12B-second gas distributor, 12C-third gas distributor, 12D-bottom gas distributor, 120-gas outlet, 121-main pipe of gas distributor, 122-gas distributor branch pipe, 13-liquid distributor, 14-catalyst support sieve plate, 15-cooling jacket, 16-reactor gas outlet, 17-reactor liquid product outlet. DETAILED DESCRIPTION

[0023] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0024] Unless otherwise expressly indicated, throughout the specification and claims, the term "comprise" or variations thereof such as "include" or "comprising" will be understood to include the stated elements or components without excluding other elements or components. In addition, the term "comprise" or variations thereof such as "include" or "comprising" may also exclude other elements or components, that is, the term "consists of" or "consists essentially of."

[0025] In this document, for the convenience of description, spatial relative terms such as "below", "beneath", "below", "above", "above", etc. may be used to describe the relationship between an element or feature and another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to include different orientations of an object in use or operation in addition to the orientation depicted in the drawings. For example, if the object in the figure is turned over, the element described as being "below" or "below" other elements or features will be oriented "above" the element or feature. Objects may also have other orientations (rotated 90 degrees, etc.) and the spatial relative terms used in this document should be interpreted accordingly. At the same time, the terms "above", "above", and "on" include an element or feature being vertically above another element or feature and an element or feature being obliquely above another element or feature, as long as the projection of one element or feature in the vertical plane is above another element or feature. Accordingly, the terms "below", "beneath", and "under" include one element or feature being vertically below another element or feature and one element or feature being obliquely below another element or feature, as long as the projection of one element or feature in the vertical plane is below the other element or feature.

[0026] In this document, the terms "first," "second," "third," etc. are used to distinguish between multiple different components or locations, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," "third," etc. may also be interchangeable.

[0027] In one aspect, the present invention provides a gas distribution unit comprising at least one gas distribution pipe, wherein the at least one gas distribution pipe comprises at least one gas outlet A and at least one gas outlet B from top to bottom, wherein the gas outlet A sprays gas downward at an injection angle εA, and the gas outlet B sprays gas downward at an injection angle εB, wherein the injection angle is the angle between the gas injection direction and the vertical direction, and εA>εB.

[0028] In this article, the term "bubble bed reactor" is also called "bubble reactor" or "boiling bed reactor", which refers to a reactor with liquid phase as continuous phase and gas phase as dispersed phase, which can be a gas-liquid two-phase reactor or a gas-liquid-solid three-phase reactor.

[0029] As used herein, the term "gas distribution unit" refers to a device capable of introducing a gaseous feed into a reactor and dispersing it into a liquid feed.

[0030] As used herein, the term "gas distribution pipe" refers to a device through which gaseous reactants are discharged. The gas distribution pipe can have any structure and shape suitable for discharging gaseous feed for reaction in a bubbling bed reactor, such as annular, spherical, cylindrical, and irregular shapes. For example, the gas distribution pipe can be a folded pipe, an annular pipe, or a straight pipe. In one embodiment, the gas distribution pipe is a straight pipe, wherein the cross-section of the straight pipe can be circular, elliptical, rectangular (including square), or polygonal, and is preferably circular.

[0031] As used herein, the term "obliquely downward" refers to a direction having a downward component and forming an angle greater than 0° but less than 90° with the vertical direction.

[0032] As used herein, the term "vertical direction" refers to a direction perpendicular to a horizontal plane.

[0033] In this document, the term "injection angle" refers to the angle between the gas injection direction and the vertical direction.

[0034] In a preferred embodiment, εA and εB are each 10-85°, preferably 20-65°. For example, εA and εB are each independently 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80° or 85°.

[0035] Preferably, the difference between εA and εB is 5-60°, preferably 5-45°. For example, the difference between εA and εB is 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55° or 60.

[0036] In a preferred embodiment, the at least one gas distribution pipe also includes at least one gas outlet C, which is located below the gas outlet A and the gas outlet B, and sprays gas downward at an injection angle εC, and εA>εB>εC, preferably the difference between εA and εB is smaller than the difference between εB and εC.

[0037] Preferably, εC is 10-65°, preferably 20-50°. For example, εC is 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60° or 65°.

[0038] More preferably, the difference between εB and εC is 5-60°, preferably 5-45°. For example, the difference between εB and εC is 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55° or 60°.

[0039] More preferably, the difference between εA and εB is 1-30°, preferably 5-25°, smaller than the difference between εB and εC. For example, the difference between εA and εB is 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, or 30° smaller than the difference between εB and εC.

[0040] According to the present invention, the gas distribution unit may include at least two, for example three or more, or four or more gas outlets at different heights, wherein the gas outlets are arranged from top to bottom, and the angle between the corresponding gas injection direction and the vertical direction, i.e., the injection angle, decreases from top to bottom. Preferably, the reduction amplitude gradually increases from top to bottom. When the gas distribution unit is used in a bubbling bed reactor, the difference in the injection angles of the two adjacent gas outlets at the top is always smaller than the difference in the injection angles of the two adjacent gas outlets at the bottom. The "two adjacent gas outlets at different heights" means that in a bubbling bed reactor, there is no gas outlet at a third height between the two gas outlets at different heights.

[0041] As used herein, the term "height" refers to the vertical distance from the horizontal plane where the lowest point of the bubbling bed reactor is located.

[0042] Without wishing to be bound by any theory, by controlling the injection angles of the gas outlets disposed at different heights in the bubbling bed reactor, the injection angles are gradually reduced from top to bottom, and preferably the difference (i.e., the magnitude of the reduction) between the injection angles of two adjacent gas outlets is gradually increased from top to bottom. The configuration of the present invention can offset the accumulation of unreacted gas feed with increasing height. This allows the gas feed to be more evenly distributed in the liquid feed throughout the bubbling bed reactor, thereby improving the conversion rate and selectivity of the reaction carried out therein. In a preferred embodiment, the gas outlet A and the gas outlet B may be located on the same or different gas distribution pipes of the at least one gas distribution pipe.

[0043] Preferably, the gas outlet A is located on the first gas distribution pipe and the gas outlet B is located on the second gas distribution pipe. More preferably, the first and second gas distribution pipes are arranged horizontally. The horizontal arrangement of the gas distribution pipes means that the central axis of the gas distribution pipes is parallel to the horizontal plane.

[0044] Still more preferably, the first and second gas distribution pipes each have a regular or irregular cross-section, and each have a shape of a straight pipe, a curved pipe, or a loop pipe.

[0045] In a preferred embodiment, a plurality of the first and second gas distribution pipes are connected to form a gas distributor.

[0046] Preferably, multiple first gas distribution pipes are connected to form a first gas distributor, and multiple second gas distribution pipes are connected to form a second gas distributor, wherein the first and second gas distributors are each arranged horizontally. Among the multiple gas distribution pipes connected to form the gas distributor, one is referred to as a main pipe, and the others are referred to as branch pipes. The main pipe and branch pipes can be connected using methods commonly used in the art.

[0047] More preferably, the first and second gas distributors each include a horizontally arranged straight main pipe and one or more straight branch pipes connected to the main pipe, and the two main pipes of the first and second gas distributors are parallel to each other, and the projections of the two main pipes on the horizontal plane form an angle δ, which ranges from 0° to 135°, preferably from 20° to 70°. When the two main pipes of the first and second gas distributors form an angle δ, the first and second gas distributors are staggered. This can further increase the degree of gas-liquid turbulence, promote mixing, and improve the conversion rate and selectivity of the reaction carried out therein.

[0048] According to the present invention, the gas outlet can be any form of device capable of discharging gas, for example, an opening or a nozzle.

[0049] As used herein, the term "opening" may have any shape suitable for outflowing gas, such as circular, elliptical, rectangular (including square), or polygonal, with circular being preferred. The size of the opening can be determined based on the shape and size of the gas distribution pipe in which it is located, the type of reaction, and other factors. Preferably, the ratio of the equivalent diameter of the opening to the equivalent diameter of the gas distribution pipe is 0.01-0.25, more preferably 0.02-0.15. The "nozzle" may have any form and structure, and its outlet is defined as the same as the "opening" above.

[0050] Even more preferably, the first and second gas distribution pipes are each a straight pipe with a circular cross-section, and the gas outlet A is an opening on the first gas distribution pipe, and the gas outlet B is an opening on the second gas distribution pipe, wherein the opening angles αA and αB are respectively equivalent to the gas injection angles εA and εB, wherein the opening angle is the angle between the straight line including the center point of the opening cross section and the center point of the cross-section circle of the corresponding gas distribution pipe and the vertical direction, preferably, there are multiple openings on the first gas distribution pipe as gas outlet A, and there are multiple openings on the second gas distribution pipe as gas outlet B.

[0051] Even more preferably, the first and second gas distribution pipes each have an open porosity of 1‰ to 60‰, preferably 1‰-45‰, more preferably 5‰ to 30‰.

[0052] In a preferred embodiment, the gas outlet A, the gas outlet B and the at least one gas outlet C are located on the same or different gas distribution pipes of the at least one gas distribution pipe.

[0053] Preferably, the gas outlet A is located on the first gas distribution pipe, the gas outlet B is located on the second gas distribution pipe, and the at least one gas outlet C is located on the third gas distribution pipe. More preferably, the first, second and third gas distribution pipes are arranged horizontally.

[0054] More preferably, the first, second and third gas distribution pipes each have a regular or irregular cross-section, and each have a shape of a straight pipe, a curved pipe and a circular pipe.

[0055] In a preferred embodiment, a plurality of the first, second and third gas distribution pipes are interconnected to form a gas distributor.

[0056] Preferably, a plurality of the first gas distribution pipes are connected to form a first gas distributor, a plurality of the second gas distribution pipes are connected to form a second gas distributor, and a plurality of the third gas distribution pipes are connected to form a third gas distributor, wherein the first, second and third gas distributors are each arranged horizontally, preferably the first, second and third gas distributors each include a horizontally arranged straight pipe-shaped main pipe and one or more straight pipe-shaped branches connected to the main pipe, more preferably the three main pipes of the first, second and third gas distributors are parallel to each other, and the projections of the three main pipes on the horizontal plane have an angle δ, and the range of δ is 0°-135°, preferably 20°-70°. When the adjacent two main pipes of the first, second and third gas distributors have an angle δ, the adjacent two of the first, second and third gas distributors are staggered. This can further increase the degree of gas-liquid turbulence, promote mixing, and improve the conversion rate and selectivity of the reaction carried out therein.

[0057] More preferably, the first, second and third gas distribution pipes are each a straight pipe with a circular cross-section, and the gas outlet A is an opening on the first gas distribution pipe, the gas outlet B is an opening on the second gas distribution pipe, and the at least one gas outlet C is an opening on the third gas distribution pipe, wherein the opening angles αA, αB, αC are respectively equivalent to the gas injection angles εA, εB, εC, wherein the opening angle is the angle between the straight line including the center point of the opening cross section and the center point of the cross-section circle of the corresponding gas distribution pipe and the vertical direction, preferably, there are multiple openings on the first gas distribution pipe as gas outlet A, there are multiple openings on the second gas distribution pipe as gas outlet B, and there are multiple openings on the third gas distribution pipe as gas outlet C.

[0058] Still more preferably, the first, second and third gas distribution pipes each have an open porosity of 1‰ to 60‰, preferably 1‰-45‰, more preferably 5‰ to 30‰.

[0059] In a preferred embodiment, the gas distribution unit further includes a bottom gas distribution pipe, which is located below all of the at least one gas distribution pipes, and the bottom gas distribution pipe has at least one gas outlet D, so as to spray gas upward at an injection angle β, wherein β refers to the angle between the injection direction and the vertical direction and is in the range of 0° to 80° or 10° to 80°, preferably 20° to 70°, and more preferably 30° to 60°.

[0060] Preferably, a plurality of bottom gas distribution pipes are interconnected to form a bottom gas distributor.

[0061] Preferably, the bottom gas distributor and the bottom gas distribution pipe have the same structure as the gas distributor and the gas distribution pipe described above, except that the former is reversed so that the gas injection direction is inclined upward.

[0062] Herein, the term "obliquely upward" refers to a direction having an upward component and forming an angle greater than 0° but less than 90° with the vertical direction.

[0063] In a second aspect, the present invention provides a bubbling bed reactor comprising the gas distribution unit according to the first aspect.

[0064] In a preferred embodiment, the height of the gas outlet A in the bubbling bed reactor is hA, and the height of the gas outlet B in the bubbling bed reactor is hB, wherein hA and hB are 10-90%, preferably 20-85%, of the total height H of the bubbling bed reactor. For example, hA and hB are each independently 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85% or 90% of the total height H of the bubbling bed reactor.

[0065] Preferably, the difference between hA and hB is 5-70%, preferably 10-60%, of the total height H of the bubbling bed reactor. For example, the difference between hA and hB is 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65% or 70% of the total height H of the bubbling bed reactor. Preferably, the difference between hA and hB is greater than the injection length of the gas injected from the gas outlet A, so that the gas injected from the gas outlet A does not contact the horizontal plane where the gas outlet B is located.

[0066] The total height H of the bubbling bed reactor can be 2 to 16 meters, for example, 2 meters, 4 meters, 6 meters, 8 meters, 10 meters, 12 meters, or 16 meters. The ratio of the total height H of the bubbling bed reactor to the reactor diameter Dr is 1.2 to 10.5, preferably 2.5 to 7. For example, H / Dr is 1.2, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 10.5.

[0067] In a preferred embodiment, the height of the gas outlet C in the bubbling bed reactor is hC, wherein hC is 10-90%, preferably 20-85%, of the total height H of the bubbling bed reactor. For example, hC is 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85% or 90% of the total height H of the bubbling bed reactor.

[0068] Preferably, the difference between hB and hC is 5-60%, more preferably 10-50%, of the total height H of the bubbling bed reactor, wherein the difference between hB and hC is the same as or different from the difference between hA and hB. For example, the difference between hB and hC and the difference between hA and hB are each independently 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or 50% of the total height H of the bubbling bed reactor, but the sum of the difference between hB and hC and the difference between hA and hB should be less than or equal to 80% of the total height H of the reactor. Preferably, the difference between two gas outlets at adjacent heights should be greater than the injection length of the gas injected from the upper gas outlet, so that the gas injected from the upper gas outlet does not contact the horizontal plane of the lower gas outlet.

[0069] In one embodiment, hA is 30-65%, preferably 30-55%, of the total height H of the bubbling bed reactor, and hB is 10-40%, preferably 20-30% of the total height H of the bubbling bed reactor.

[0070] In one embodiment, hA is 50-85%, preferably 60-80%, of the total height H of the bubbling bed reactor, hB is 30-65%, preferably 30-55%, and hC is 10-40%, preferably 20-30%, of the total height H of the bubbling bed reactor.

[0071] In a preferred embodiment, the bubbling bed reactor includes at least one catalyst bed composed of catalyst particles, wherein the gas distribution unit includes first and second gas distribution pipes, each independently positioned within the at least one catalyst bed. The first and second gas distribution pipes each have a height within the catalyst bed of 10-90%, preferably 20-85%, and more preferably 25-80% of the catalyst bed height.

[0072] Preferably, the bubbling bed reactor includes two catalyst beds, and the first and second gas distribution pipes are respectively located in the first and second catalyst beds. The height of the first distribution pipe in the first catalyst bed is 10-90%, preferably 20-85%, and more preferably 25-80% of the height of the first catalyst bed. The height of the second gas distribution pipe in the second catalyst bed is 10-90%, preferably 20-85%, and more preferably 25-80% of the height of the second catalyst bed.

[0073] More preferably, the first and second catalyst beds are each composed of catalyst particles, preferably spherical catalyst particles, wherein the average particle sizes of the catalyst particles in the first and second catalyst beds are P1 and P2, respectively, and P1>P2;

[0074] Still more preferably, the bubbling bed reactor further comprises a bottom gas distributor. When the bubbling bed reactor does not include a catalyst bed, the bottom gas distributor is located below all of the at least one gas distribution pipes. When the bubbling bed reactor includes at least one catalyst bed, the bubbling bed reactor includes at least one bottom gas distributor, which is respectively located in the bubbling bed reactor space below each catalyst bed. In one variation, the bubbling bed reactor includes at least one catalyst bed, and one bottom gas distributor is located in the bubbling bed reactor space below all of the at least one catalyst bed.

[0075] In a preferred embodiment, the bubbling bed reactor includes at least one catalyst bed composed of catalyst particles, wherein the gas distribution unit includes first, second, and third gas distribution pipes, each independently positioned within the at least one catalyst bed. The height of the first, second, and third gas distribution pipes within the corresponding catalyst bed is 10-90%, preferably 20-85%, and more preferably 25-80% of the catalyst bed height.

[0076] Preferably, the first, second, and third gas distribution pipes are located in the first, second, and third catalyst beds, respectively. The height of the first distribution pipe in the first catalyst bed is 10-90%, preferably 20-85%, and more preferably 25-80% of the height of the first catalyst bed. The height of the second gas distribution pipe in the second catalyst bed is 10-90%, preferably 20-85%, and more preferably 25-80% of the height of the second catalyst bed. The height of the third distribution pipe in the third catalyst bed is 10-90%, preferably 20-85%, and more preferably 25-80% of the height of the third catalyst bed.

[0077] More preferably, the first, second and third catalyst beds are each composed of catalyst particles, wherein the average particle sizes of the catalyst particles in the first, second and third catalyst beds are P1, P2 and P3 respectively, and P1>P2>P3.

[0078] Still more preferably, the bubbling bed reactor further comprises a bottom gas distributor. When the bubbling bed reactor does not include a catalyst bed, the bottom gas distributor is located below all of the at least one gas distribution pipes. When the bubbling bed reactor includes at least one catalyst bed, the bubbling bed reactor includes at least one bottom gas distributor, which is respectively located in the bubbling bed reactor space below each catalyst bed. In one variation, the bubbling bed reactor includes at least one catalyst bed, and one bottom gas distributor is located in the bubbling bed reactor space below all of the at least one catalyst bed.

[0079] In a preferred embodiment, the bubbling bed reactor further comprises a liquid distribution pipe. When the bubbling bed reactor does not include a catalyst bed, the height of the liquid distribution pipe in the bubbling bed reactor is greater than the height of all the at least one gas distribution pipes in the bubbling bed reactor. When the bubbling bed reactor includes at least one catalyst bed, the height of the liquid distribution pipe is greater than the height of all the at least one catalyst bed in the bubbling bed reactor. The liquid distribution pipe inputs the liquid feedstock into the bubbling bed reactor to submerge all the gas distribution pipes and catalyst beds.

[0080] Preferably, multiple liquid distribution pipes are interconnected to form a liquid distributor. The liquid distribution pipes and liquid distributor can have any shape and structure used in the field of bubbling bed reactors for introducing liquid reactants. Preferably, the liquid distributor has multiple openings for introducing liquid reactants and an open porosity of 1‰-65‰, preferably 5‰-60‰, and more preferably 10‰-50‰. Preferably, the ratio of the equivalent diameter of the openings to the equivalent diameter of the liquid distribution pipe is 0.02-0.3, more preferably 0.05-0.2.

[0081] In a preferred embodiment, the bubbling bed reactor comprises two or more catalyst beds, preferably two catalyst beds, which are composed of catalyst particles, wherein the average particle size of the catalyst particles in each catalyst bed is larger than the average particle size of the catalyst particles in the catalyst bed below it.

[0082] In a preferred embodiment, the average particle size of the catalyst particles in the catalyst bed is independently 0.01 mm to 10 mm, preferably 0.1 mm to 5 mm, more preferably 0.3 mm to 3 mm.

[0083] In one embodiment, the gas distribution unit comprises two catalyst beds, the average particle size P1 of the catalyst particles in the upper catalyst bed being larger than the average particle size P2 of the catalyst particles in the lower catalyst bed. Preferably, P1 is 0.1 mm to 10 mm, preferably 1 mm to 5 mm, more preferably 1 mm to 3 mm, and P2 is 0.01 mm to 5 mm, preferably 0.1 mm to 2 mm, more preferably 0.3 mm to 1 mm.

[0084] In one embodiment, the present invention comprises at least one catalyst bed in a bubbling bed reactor, and at least one gas distributor of the present invention is installed within each catalyst bed. This configuration can improve gas uniformity, increase feed-catalyst contact, and reduce catalyst backmixing, thereby increasing reaction rate, conversion, and selectivity.

[0085] In a preferred embodiment, at least two catalyst beds are set, and the bed positioned at a higher position in the bubbling bed reactor comprises the larger catalyst particles of average particle size, and the bed positioned at a lower position in the bubbling bed reactor comprises the smaller catalyst particles of average particle size. On the one hand, since the diffusion path of the reactant in the smaller catalyst particles of average particle size is shorter, and the specific surface area of ​​the smaller catalyst particles of average particle size is larger, the reaction efficiency of the reactant on the smaller catalyst particles of average particle size is higher. Accordingly, the catalyst bed positioned at a lower position in the bubbling bed reactor comprises the smaller catalyst particles of average particle size, which makes more gaseous reactants react, and less unreacted gaseous reactants rise along the reactor and leave the reactor. On the other hand, the settling velocity of the larger catalyst particles of average particle size in the liquid is larger, and the reaction efficiency of the reactant thereon is lower. As mentioned above, a plurality of gas outlets are provided at the different heights of the bubbling bed reactor, and the injection angle of its injected gas is reduced successively from top to bottom, preferably reducing the injection angle in the mode of increasing with amplitude from top to bottom. This configuration increases the horizontal velocity component of the gas entering the reactor from bottom to top, which increases the turbulence of the liquid phase and catalyst particles, thereby offsetting the adverse effects of a larger average particle size on reaction efficiency. The configuration of the catalyst layer and the gas distributor can lead to a synergistic effect, further improving the conversion rate and selectivity of the reaction.

[0086] In a third aspect, the present invention provides a reaction method, comprising the steps of: using the gas distribution unit according to the first aspect to inject gaseous reactants into a bubbling bed reactor to react with liquid reactants therein.

[0087] In a preferred embodiment, the method comprises the following steps:

[0088] a) supplying liquid reactants into the bubbling bed reactor and submerging the gas distribution unit, and when the bubbling bed reactor does not include a solid particle catalyst bed, the liquid reactants submerge 90% to 95% of the space of the reactor height, or when the bubbling bed reactor includes one or more catalyst beds, the liquid reactants submerge all catalyst beds; and

[0089] b) supplying the gaseous reactants into the bubbling bed reactor through the gas distribution unit.

[0090] Reaction method according to the present invention can be used for carrying out the reaction of any gaseous reactant and liquid reactant, and no matter whether there is catalyst, or catalyst form is homogeneous catalyst or heterogeneous catalyst.In a preferred embodiment, described reaction method is for synthesizing ethylene carbonate, propylene carbonate or butylene carbonate, wherein liquid reactant ethylene oxide and gaseous reactant carbon dioxide generate ethylene carbonate under the effect of solid catalyst particles, liquid reactant propylene oxide and gaseous reactant carbon dioxide generate propylene carbonate under the effect of solid catalyst particles, or liquid reactant butylene oxide and gaseous reactant carbon dioxide generate butylene carbonate under the effect of solid catalyst particles.

[0091] Preferred embodiments of the bubbling bed reactor of the present application will be described in detail below with reference to the accompanying drawings, but the scope of the present application is not limited to these preferred embodiments.

[0092] As shown in Figure 1, in a preferred embodiment, the bubbling bed reactor 1 of the present invention is a cylindrical tank structure. A cooling jacket 15 is wrapped around the outer wall of the bubbling bed reactor 1. The bubbling bed reactor 1 includes a catalyst bed 11, a first gas distributor 12A, a second gas distributor 12B, a third gas distributor 12C, a bottom gas distributor 12D, and a liquid distributor 13. The catalyst bed 11 is composed of catalyst particles between upper and lower support sieve plates 14. The liquid distributor 13 is arranged above the catalyst bed 11. The bottom gas distributor 12D is arranged below the catalyst bed 11. The first gas distributor 12A, the second gas distributor 12B and the third gas distributor 12C are arranged in the catalyst bed 11 from top to bottom. The height of the first gas distributor 12A is less than or equal to 80% of the height of the catalyst bed. In addition, the bubbling bed reactor 1 also includes a reactor gas outlet 16 at the top and a reactor liquid product outlet 17 at the bottom. The first gas distributor 12A, the second gas distributor 12B, the third gas distributor 12C, the bottom gas distributor 12D, the liquid distributor 13, and the supporting sieve plate 14 are all placed horizontally.

[0093] The liquid distributor 13 includes a horizontally arranged liquid distribution pipe as a main pipe and branch pipes, wherein the branch pipes are connected to the main pipe and perpendicular to the main pipe. The liquid outlets on the liquid distribution pipes, which serve as the main pipe and the branch pipes, are at least one row of openings with a porosity of 1‰ to 65‰. The at least one row of openings is symmetrically distributed and faces vertically downward or obliquely downward.

[0094] The bottom gas distributor 12D includes a horizontally arranged bottom gas distribution pipe as a main pipe and a branch pipe, wherein the branch pipe is connected to and perpendicular to the main pipe. The gas outlets on the bottom gas distribution pipe, serving as both the main pipe and the branch pipe, are two rows of openings. These two rows of openings are symmetrically distributed and have an upwardly inclined opening angle αD. The opening angle is the angle between the center point of the opening cross section and the center point of the corresponding gas distribution pipe cross section circle and the vertical direction. The opening angle αD is equal to the gas injection angle β, which ranges from 10° to 80°. In one variation, the gas outlets on the bottom gas distribution pipe, serving as both the main pipe and the branch pipe, are a single row of openings, with the opening angle αD equal to the gas injection angle β, which ranges from 0° to 80°.

[0095] As shown in Figure 2, the third gas distributor 12C includes a horizontally arranged second gas distribution pipe as a main pipe 121 and a branch pipe 122, wherein the branch pipe 122 is connected to the main pipe 121 and is perpendicular to the main pipe 121. As shown in Figure 3, the main pipe 121 and the branch pipe 122 each independently include two rows of openings as gas outlets. They are arranged symmetrically and have an opening angle αC that is tilted downward, wherein the opening angle is the angle between the center point of the opening cross section and the center point of the cross section circle of the corresponding gas distribution pipe and the vertical direction. The opening angle αC of the gas outlet is equal to the gas injection angle εC. In one variation, the main pipe 121 and the branch pipe 122 each independently include a row of openings as gas outlets, wherein the openings have an opening angle αC that is tilted downward. In addition, the porosity of each of the main pipe 121 and the branch pipe 122 is 1‰-60‰, preferably 1‰-45‰. Preferably, the third gas distributor 12C has the same structure as the bottom gas distributor 12D, and the main pipe 121 of the third gas distributor 12C is arranged to have an angle δ with the horizontal plane projection of the main pipe of the bottom gas distributor 12D, and the angle δ is in the range of 0°-90°, preferably 0-45°.

[0096] The first gas distributor 12A and the second gas distributor 12B have the same structure as the third gas distributor 12C, except that the opening angles of the openings on the gas distribution pipes of the first gas distributor 12A and the second gas distributor 12B are αA and αB, respectively, where αA>αB>αC. Preferably, the difference between αA and αB is less than the difference between αB and αC. The opening angles αA, αB, and αC of the gas outlets are equal to the gas injection angles εA, εB, and εC, respectively. Preferably, the horizontal projections of two adjacent main pipes of the first gas distributor 12A, the second gas distributor 12B, and the third gas distributor 12C each independently form an angle δ, with δ ranging from 0° to 135°, preferably from 20° to 70°.

[0097] As shown in Figure 4, in another preferred embodiment, the bubbling bed reactor 1 of the present invention is a cylindrical tank structure. A cooling jacket 15 is wrapped around the outer wall of the bubbling bed reactor 1. The bubbling bed reactor 1 includes an upper catalyst bed 11A, a lower catalyst bed 11B, a first gas distributor 12A arranged in the upper catalyst bed 11A, a bottom gas distributor 12D1 arranged between the upper catalyst bed 11A and the lower catalyst bed 11B, a second gas distributor 12B arranged in the lower catalyst bed 11B, a bottom gas distributor 12D2 arranged below the lower catalyst bed 11B, and a liquid distributor 13. The upper catalyst bed 11A and the lower catalyst bed 11B are each independently composed of catalyst particles between upper and lower support sieve plates 14, wherein the average particle size of the catalyst particles in the upper catalyst bed 11A is greater than the average particle size of the catalyst particles in the lower catalyst bed 11B. The liquid distributor 13 is arranged above the upper catalyst bed 11A. In addition, the bubble bed reactor 1 further includes a reactor gas outlet 16 at the top and a reactor liquid product outlet 17 at the bottom.

[0098] The first gas distributor 12A, the second gas distributor 12B, the bottom gas distributor 12D1 and the bottom gas distributor 12D2, and the liquid distributor 13 have the structures mentioned in the description of the bubbling bed reactor shown in FIG1 , and will not be described in detail here.

[0099] Preferred embodiments of the reaction method of the present application will be described in detail below with reference to the accompanying drawings, but the scope of the present application is not limited to these preferred embodiments.

[0100] In bubbling bed reactor 1 shown in Figure 1, carry out the reaction of synthesizing ethylene carbonate by oxyethane and carbon dioxide, by the reaction of synthesizing propylene carbonate by propylene oxide and carbon dioxide or by the reaction of synthesizing butylene carbonate by butylene oxide and carbon dioxide.Liquid phase (any liquid among oxyethane, propylene oxide, butylene oxide three) enters in the bubbling bed reactor 1 by liquid distributor 13, makes liquid phase submerged catalyst bed 11.Gas phase (carbon dioxide) enters in the reactor 1 by the first gas distributor 12A, the second gas distributor 12B, the 3rd gas distributor 12C and bottom gas distributor 12D.Liquid phase oxyethane and gaseous carbon dioxide react in catalyst bed 11 and generate oxyethane, liquid phase propylene oxide and gaseous carbon dioxide react in catalyst bed 11 and generate propylene carbonate, or liquid phase butylene oxide and gaseous carbon dioxide react in catalyst bed 11 and generate butylene carbonate. The reaction product flows out of the reactor 1 in liquid form through the reactor liquid product outlet 17 , and unreacted carbon dioxide is discharged from the reactor 1 through the reactor gas outlet 16 .

[0101] This application may include the following implementations:

[0102] 1. A gas distribution unit, characterized in that it is applied to a gas-liquid-solid three-phase bubbling bed reactor, comprising:

[0103] a bottom gas distributor, which is disposed below the catalyst bed and bubbles upward;

[0104] A first gas distributor is provided inside the catalyst bed and bubbles downward.

[0105] 2 . The gas distribution unit according to claim 1 , wherein a granular solid catalyst is provided in the catalyst bed and is confined within the bed.

[0106] 3 . The gas distribution unit according to claim 1 , wherein the first gas distributor is arranged in 1 to 4 layers, preferably 2 layers, at different heights within the catalyst bed.

[0107] 4 . The gas distribution unit according to claim 1 , wherein bottom gas holes for bubbling upward are uniformly formed on the bottom gas distributor; and first gas holes for bubbling downward are uniformly formed on the first gas distributor.

[0108] 5. The gas distribution unit according to claim 4 is characterized in that the first air holes are arranged in two or more rows; when there are two rows of first air holes, the two air holes are symmetrical and inclined downward, and the angle α between the air hole direction and the vertical direction is in the range of 25°-65°.

[0109] 6 . The gas distribution unit according to claim 5 , wherein when the first gas distributor is provided in two layers, the angle α of the first gas holes in the upper layer is greater than or equal to the angle α of the first gas holes in the lower layer.

[0110] 7. The gas distribution unit according to claim 6, wherein the difference between the angles α between the upper and lower layers is 5°-25°.

[0111] 8. The gas distribution unit according to claim 3, characterized in that when the first gas distributors are provided in two or more layers, the first gas distributors in adjacent layers have an overall tilt angle δ in the horizontal direction, and the angle range of δ is 0°-135°.

[0112] 9 . The gas distribution unit according to claim 3 , wherein the installation height of the first gas distributor in the uppermost layer is less than or equal to 80% of the height of the catalyst bed.

[0113] 10. The gas distribution unit according to claim 1 is characterized in that the bottom air holes are arranged in two or more rows; when there are two rows of bottom air holes, the two air holes are symmetrical and inclined upward, and the angle β between the air hole direction and the vertical direction is in the range of 30°-60°.

[0114] 11. The gas distribution unit according to claim 1, characterized in that the bottom gas distributor and the first gas distributor are composed of a main pipe and multiple branch pipes perpendicular to each other, and the coverage of the branch pipes is adapted to the cross-section of the bubbling bed reactor; the porosity of the main pipe and the branch pipe is 1‰-45‰.

[0115] 12. A bubbling bed reactor, characterized in that it is applied to the gas distribution unit according to any one of claims 1 to 11.

[0116] 13. The bubbling bed reactor according to claim 12, further comprising:

[0117] The liquid distributor is arranged above the catalyst bed and is used to provide liquid feed for the reaction; the liquid feed submerges the solid catalyst bed.

[0118] The bubbling bed reactor according to claim 13 , wherein the porosity of the liquid distributor is 1‰-65‰.

[0119] 15. The bubbling bed reactor according to claim 12, further comprising:

[0120] The catalyst bed is one layer or multiple layers. When the catalyst bed is multiple layers, the gas distribution unit is independently set in each bed.

[0121] 16 . The bubbling bed reactor according to claim 15 , wherein supporting sieve plates are respectively provided at the upper end and the lower end of the catalyst bed.

[0122] 17 . The bubbling bed reactor according to claim 12 , wherein the outer wall of the bubbling bed reactor is wrapped with a cooling jacket.

[0123] 18. A reaction method, characterized in that the bubbling bed reactor according to any one of claims 12 to 17 is used, comprising:

[0124] The liquid feed enters the reactor through the liquid distributor and establishes a liquid level that submerges the catalyst bed;

[0125] The gas feed is respectively sprayed through the bottom gas distributor and the first gas distributor, and the bubbles from the first gas distributor are turned back in the liquid phase at the catalyst bed;

[0126] Under the combined action of the returning bubbles and the rising bubbles from the bottom gas distributor, the solid catalyst particles are in a tumbling motion state in the bed.

[0127] 19. The reaction method according to claim 18, wherein the reaction method is used to synthesize ethylene carbonate.

[0128] 20. The reaction method according to claim 19, wherein the liquid feed is ethylene oxide and the gas feed is carbon dioxide.

[0129] Example

[0130] The following examples are used to further illustrate the present application, but are not intended to limit the present application.

[0131] The catalyst used in the following examples and comparative examples is commercial catalyst particles from Sinopec (Shanghai) Petrochemical Research Institute Co., Ltd., with the trade name SEC-22.

[0132] Example 1

[0133] A bubbling bed reactor 1 is provided. The inner diameter of the bubbling bed reactor 1 is 1600 mm and the reactor height is 6000 mm. The bubbling bed reactor 1 includes a catalyst bed 11 (which is composed of the commercial catalyst particles), a first gas distributor 12A and a second gas distributor 12B arranged from top to bottom in the catalyst bed, a bottom gas distribution pipe 12D arranged below the catalyst bed 11, and a liquid distributor 13 arranged above the catalyst bed 11. The first gas distributor 12A, the second gas distributor 12B and the bottom gas distributor 12D are each composed of a horizontally arranged gas distribution main pipe 121 and five gas distribution branch pipes 122, wherein the branch pipes 122 are connected to the main pipe 121 and are perpendicular to the main pipe 121. The angle δ between the horizontal plane projections of the main pipes of the first gas distributor 12A and the second gas distributor 12B and the main pipe of the bottom gas distributor 12D is 0°. Two rows of symmetrically distributed and downwardly inclined openings are provided on the main pipe and branch pipe of the first gas distributor 12A and the second gas distributor 12B. The angles between the center point of the opening cross section and the line where the center point of the cross section of the corresponding gas distribution pipe lies and the vertical direction, i.e., the opening angles are α and α, respectively. 12A =55° and α 12B =45°. Correspondingly, the angles between the gas flowing out and the vertical direction, i.e. the injection angles, are ε 12A =55° and ε 12B=45°. The main and branch pipes of the bottom gas distributor 12D have two rows of symmetrically distributed, upwardly inclined openings, with the gas flowing out having an angle with the vertical, i.e., an injection angle β, of 30°. The second gas distributor 12B is installed at a height of 25% of the height of the catalyst bed 11, and the first gas distributor 12A is installed at a height of 50% of the height of the catalyst bed 11. The porosity of the first gas distributor 12A, the second gas distributor 12B, and the bottom gas distributor 12D is 25‰, while the porosity of the liquid distributor 13 is 45‰.

[0134] The reaction of synthesizing ethylene carbonate from ethylene oxide and carbon dioxide was carried out in the bubble bed reactor 1. The conversion rate and selectivity achieved in this example were 91.8% and 99.1%.

[0135] Example 2

[0136] A bubbling bed reactor 1 identical to the bubbling bed reactor 1 of Example 1 is provided, except that the opening angle α of the openings on the gas distribution pipe of the first gas distributor 12A is 12A =65°, the opening angle α of the openings on the gas distribution pipe of the second gas distributor 12B 12B =45°. Accordingly, the injection angles of the gas flowing out of the openings on the first gas distributor 12A and the second gas distributor 12B are ε 12A =65° and ε 12B =45°.

[0137] The reaction of synthesizing ethylene carbonate from ethylene oxide and carbon dioxide was carried out in the bubble bed reactor 1. The conversion rate and selectivity achieved in this example were 93.5% and 99.8%.

[0138] The only difference between Example 2 and Example 1 is the difference in injection angle: the injection angle difference in Example 1 is 10°, while the injection angle difference in Example 2 is 20°. As the injection angle difference increases, both conversion and selectivity are improved.

[0139] Comparative Example 1

[0140] A bubbling bed reactor 1 is provided that is identical to the bubbling bed reactor 1 of Example 1, except that the opening angles of the openings of the first gas distributor 12A and the second gas distributor 12B are equal, and α 12A =α 12B =45°. Correspondingly, the injection angle ε 12A =ε 12B =45°.

[0141] The reaction of synthesizing ethylene carbonate from ethylene oxide and carbon dioxide was carried out in the bubble bed reactor 1. The conversion rate and selectivity achieved in this comparative example were 87.1% and 96.5%.

[0142] Compared with Examples 1 and 2, the injection angle difference in Comparative Example 1 was reduced to 0°, i.e., the injection angle of the openings of the upper gas distributor was the same as the injection angle of the openings of the lower gas distributor. This resulted in a significant decrease in both conversion and selectivity.

[0143] Example 3

[0144] A bubbling bed reactor 1 is provided. The inner diameter of the bubbling bed reactor 1 is 1600 mm and the reactor height is 6000 mm. The bubbling bed reactor 1 includes a catalyst bed 11 (which is composed of the commercial catalyst particles), a first gas distributor 12A, a second gas distributor 12B, and a third gas distributor 12C arranged from top to bottom in the catalyst bed, a bottom gas distribution pipe 12D arranged below the catalyst bed 11, and a liquid distributor 13 arranged above the catalyst bed 11. The first gas distributor 12A, the second gas distributor 12B, the third gas distributor 12C, and the bottom gas distribution pipe 12D are each composed of a horizontally arranged gas distribution main pipe 121 and five gas distribution branch pipes 122, wherein the branch pipes 122 are connected to the main pipe 121 and are perpendicular to the main pipe 121. The angle between the horizontal plane projections of the main pipes of the first gas distributor 12A, the second gas distributor 12B, and the third gas distributor 12C and the main pipe of the bottom gas distributor 12D is δ = 0°. Two rows of symmetrically distributed and downwardly inclined openings are provided on the main and branch pipes of the first gas distributor 12A, the second gas distributor 12B, and the third gas distributor 12C. The angles between the center point of the opening cross section and the line where the center point of the cross section of the corresponding gas distribution pipe lies and the vertical direction, i.e., the opening angles are α 12A =75°、α 12B =68° and α 12C =45°. Correspondingly, the angles between the gas flowing out and the vertical direction, i.e. the injection angles, are ε 12A =75°、ε 12B =68° and ε 12C =45°. Two rows of symmetrically distributed and upwardly inclined air holes are provided on the main pipe and branch pipe of the bottom gas distributor 12D, and the angle between the gas flowing out and the vertical direction, i.e., the injection angle β, is 30°. The installation height of the third gas distributor 12C is 25% of the height of the catalyst bed 11, the installation height of the second gas distributor 12B is 50% of the height of the catalyst bed 11, and the installation height of the first gas distributor 12A is 70% of the height of the catalyst bed 11. The porosity of the first gas distributor 12A, the second gas distributor 12B, the third gas distributor 12C and the bottom gas distributor 12D is 25‰, and the porosity of the liquid distributor 13 is 45‰.

[0145] The reaction of synthesizing ethylene carbonate from ethylene oxide and carbon dioxide was carried out in the bubble bed reactor 1. The conversion rate achieved in this example was 96.5% and the selectivity was greater than 99.9%.

[0146] Comparative Example 2

[0147] A bubbling bed reactor 1 identical to that of Example 3 is provided, except that the opening angles of the openings of the first gas distributor 12A, the second gas distributor 12B, and the third gas distributor 12C are equal, i.e., α 12A =α 12B =α 12C =45°. Correspondingly, the injection angles are ε 12A =ε 12B =ε 12C =45°.

[0148] The reaction of synthesizing ethylene carbonate from ethylene oxide and carbon dioxide was carried out in the bubble bed reactor 1. The conversion rate and selectivity achieved in this comparative example were 89.2% and 98.0%.

[0149] The difference between Comparative Example 2 and Example 3 is that the injection angles (and their differences) of the openings of the three gas distributors are different. The differences between the injection angles of Comparative Example 2 are all 0°. The difference between the injection angles of the openings of the first gas distributor 12A and the second gas distributor 12B of Example 3 is 7°, and the difference between the injection angles of the openings of the second gas distributor 12B and the third gas distributor 12C is 23°. In other words, from top to bottom, the difference in the injection angles of the openings of two gas distributors at adjacent heights increases. Accordingly, relative to Example 3, the conversion rate and selectivity achieved in Comparative Example 2 are both reduced.

[0150] Comparative Example 3

[0151] A bubbling bed reactor 1 identical to that of Example 3 is provided, except that the opening angle α of the opening of the first gas distributor 12A is 12A =75°, the opening angle α of the opening of the second gas distributor 12B 12B =60°, the opening angle α of the opening of the third gas distributor 12C 12C =45°. Correspondingly, the injection angles are ε 12A =75°, ε 12B = 60°, and ε 12C =45°.

[0152] The reaction of synthesizing ethylene carbonate from ethylene oxide and carbon dioxide was carried out in the bubble bed reactor 1. The conversion rate achieved in this comparative example was 94.1% and the selectivity was greater than 99.9%.

[0153] In Comparative Example 3, the injection angles of the gas distributor openings gradually decrease from top to bottom, and the difference between the injection angles of two gas distributor openings at adjacent heights is the same, 15°. Compared with Comparative Example 2, the injection angles of Comparative Example 3 gradually decrease from top to bottom, and both conversion and selectivity are improved. Compared with Example 3, the difference between the injection angles of Comparative Example 3 remains unchanged, resulting in a decrease in conversion.

[0154] Comparative Example 4

[0155] A bubbling bed reactor 1 identical to that of Example 3 is provided, except that the opening angle α of the opening of the first gas distributor 12A is 12A =75°, the opening angle α of the opening of the second gas distributor 12B 12B =52°, the opening angle α of the opening of the third gas distributor 12C 12C =45°. Correspondingly, the injection angles are ε 12A =75°, ε 12B =52°, and ε 12C =45°.

[0156] The reaction of synthesizing ethylene carbonate from ethylene oxide and carbon dioxide was carried out in the bubble bed reactor 1. The conversion rate and selectivity achieved in this comparative example were 92.2% and 99.3%.

[0157] In Comparative Example 4, the injection angles of the gas distributor openings gradually decrease from top to bottom, and the difference between the injection angles also gradually decreases. Compared with Comparative Example 2, the injection angles of Comparative Example 4 gradually decrease from top to bottom, and the conversion rate and selectivity are improved. In contrast to Example 3, the difference between the injection angles of the openings of two gas distributors at adjacent heights in Comparative Example 4 gradually decreases from top to bottom, resulting in a decrease in conversion rate and selectivity.

[0158] Example 4

[0159] A bubbling bed reactor 1 identical to the bubbling bed reactor 1 of Example 1 is provided, except that the angle δ between the horizontal projections of the main pipe of the first gas distributor 12A and the main pipe of the bottom gas distributor 12D is 55°, and the angle δ between the horizontal projections of the main pipe of the second gas distributor 12B and the main pipe of the bottom gas distributor 12D is 30°.

[0160] The reaction of synthesizing ethylene carbonate from ethylene oxide and carbon dioxide was carried out in the bubble bed reactor 1. The conversion rate and selectivity achieved in this example were 92.7% and 99.6%.

[0161] The only difference between Example 4 and Example 1 is the angle δ. It can be seen that the existence of the angle δ will improve the reaction conversion rate and selectivity.

[0162] Comparative Example 5

[0163] A bubbling bed reactor 1 identical to the bubbling bed reactor 1 of Example 4 was provided, except that only the first gas distributor 12A was provided in the catalyst bed.

[0164] The reaction of synthesizing ethylene carbonate from ethylene oxide and carbon dioxide was carried out in the bubble bed reactor 1. The conversion rate and selectivity achieved in this comparative example were 82.0% and 93.5%.

[0165] Comparative Example 6

[0166] A bubbling bed reactor 1 is provided that is identical to the bubbling bed reactor 1 of Example 4, except that the opening angles of the openings of the first gas distributor 12A and the second gas distributor 12B are α 12A =30° and α 12B =60°. Correspondingly, the injection angles are ε 12A =30° and ε 12B =60°.

[0167] The reaction of synthesizing ethylene carbonate from ethylene oxide and carbon dioxide was carried out in the bubble bed reactor 1. The conversion rate and selectivity achieved in this comparative example were 86.1% and 95.1%.

[0168] Example 5

[0169] A bubbling bed reactor 1 is provided. The inner diameter of the bubbling bed reactor 1 is 1600 mm and the reactor height is 6000 mm. The bubbling bed reactor 1 includes a catalyst bed 11 (which is composed of the catalyst particles), gas distributors 12A and 12B arranged from top to bottom in the catalyst bed, a bottom gas distribution pipe 12D arranged below the catalyst bed 11, and a liquid distributor 13 arranged above the catalyst bed 11. The first gas distributor 12A, the second gas distributor 12B and the bottom gas distributor 12D are each composed of a horizontally arranged gas distribution main pipe 121 and five gas distribution branch pipes 122, wherein the branch pipes 122 are connected to the main pipe 121 and are perpendicular to the main pipe 121. The angle δ between the horizontal plane projection of the main pipe of the first gas distributor 12A and the main pipe of the bottom gas distributor 12D is 45°, and the angle δ between the horizontal plane projection of the main pipe of the second gas distributor 12B and the main pipe of the bottom gas distributor 12D is 0°. Two rows of symmetrically distributed and downwardly inclined openings are provided on the main pipe and branch pipe of the first gas distributor 12A and the second gas distributor 12B. The angles between the center point of the opening cross section and the line where the center point of the cross section of the corresponding gas distribution pipe lies and the vertical direction, i.e., the opening angles are α and α, respectively. 12A=70° and α 12B =60°. Correspondingly, the angles between the gas flowing out and the vertical direction, i.e. the injection angles, are ε 12A =70° and ε 12B =60°. The main and branch pipes of the bottom gas distributor 12D have two rows of symmetrically distributed, upwardly inclined gas holes. The gas flowing out of these holes has an angle with the vertical direction, i.e., an injection angle β = 45°. The second gas distributor 12B is installed at a height of 30% of the height of the catalyst bed 11, and the first gas distributor 12A is installed at a height of 60% of the height of the catalyst bed 11. The porosity of the first gas distributor 12A, the second gas distributor 12B, and the bottom gas distributor 12D is 15‰, and the porosity of the liquid distributor 13 is 40‰.

[0170] The reaction of synthesizing ethylene carbonate from ethylene oxide and carbon dioxide was carried out in the bubble bed reactor 1. The conversion rate and selectivity achieved in this example were 90.8% and 98.6%.

[0171] Example 6

[0172] A bubbling bed reactor 1 is provided. The inner diameter of the bubbling bed reactor 1 is 1600 mm and the reactor height is 6000 mm. The bubbling bed reactor 1 includes an upper catalyst bed 11A and a lower catalyst bed 11B (each of which is independently composed of the commercial catalyst particles), a first gas distributor 12A arranged in the upper catalyst bed 11A, a second gas distributor 12B arranged in the lower catalyst bed 11B, a bottom gas distributor 12D1 arranged between the catalyst beds 11A and 11B, a bottom gas distributor 12D2 arranged below the lower catalyst bed 11B, and a liquid distributor 13 arranged above the upper catalyst bed 11A. The first gas distributor 12A, the second gas distributor 12B, and the bottom gas distributors 12D1 and 12D2 are each composed of a horizontally arranged gas distribution main pipe 121 and five gas distribution branch pipes 122, wherein the branch pipes 122 are connected to the main pipe 121 and are perpendicular to the main pipe 121. The angle between the horizontal projections of the main pipes of the first gas distributor 12A and the second gas distributor 12B and the main pipes of the bottom gas distributors 12D1 and 12D2 is δ = 0°. Two rows of symmetrically distributed and downwardly inclined openings are provided on the main pipes and branch pipes of the first gas distributor 12A and the second gas distributor 12B. The angle between the center point of the opening cross section and the line containing the center point of the cross section circle of the corresponding gas distribution pipe and the vertical direction, i.e., the opening angles, are α and α, respectively. 12A =65° and α 12B =45°. Accordingly, the angle between the gas flowing out and the vertical direction, that is, the injection angle, is ε 12A =65° and ε 12B=45°. Two rows of symmetrically distributed, upwardly inclined gas holes are provided on the main and branch pipes of the bottom gas distributors 12D1 and 12D2. The angle between the gas flowing out and the vertical direction, i.e., the injection angle β, is 45°. The installation height of the first gas distributor 12A is 25% of the height of the upper catalyst bed 11A, and the installation height of the second gas distributor 12B is 25% of the height of the lower catalyst bed 11B. The porosity of the first gas distributor 12A, the second gas distributor 12B, and the bottom gas distributors 12D1 and 12D2 is 25‰, and the porosity of the liquid distributor 13 is 45‰. The average diameter of the catalyst particles in the upper catalyst bed 11A is 1.4 mm, and the average diameter of the catalyst particles in the lower catalyst bed 11B is 0.5 mm.

[0173] The reaction of synthesizing ethylene carbonate from ethylene oxide and carbon dioxide was carried out in the bubble bed reactor 1. The conversion rate achieved in this example was 97.5%, and the selectivity was greater than 99.9%.

[0174] Comparative Example 7

[0175] A bubbling bed reactor 1 was provided that was the same as the bubbling bed reactor 1 of Example 6, except that both the upper catalyst bed 11A and the lower catalyst bed 11B were composed of catalyst particles having an average diameter of 0.95 mm.

[0176] The reaction of synthesizing ethylene carbonate from ethylene oxide and carbon dioxide was carried out in the bubble bed reactor 1. The conversion rate achieved in this comparative example was 95.4%, and the selectivity was greater than 99.9%.

[0177] The only difference between Comparative Example 7 and Example 6 is that the upper catalyst layer and the lower catalyst layer are composed of catalyst particles with different average diameters. Compared with Example 6, the reaction performance of Comparative Example 7 is reduced.

[0178] Comparative Example 8

[0179] A bubbling bed reactor 1 identical to that of Example 6 was provided, except that the upper catalyst bed 11A consisted of catalyst particles having an average diameter of 0.5 mm, and the lower catalyst bed 11B consisted of catalyst particles having an average diameter of 1.4 mm.

[0180] The reaction of synthesizing ethylene carbonate from ethylene oxide and carbon dioxide was carried out in the bubble bed reactor 1. The conversion rate and selectivity achieved in this comparative example were 92.4% and 99.4%.

[0181] The only difference between Comparative Example 8 and Example 6 is that the upper catalyst layer and the lower catalyst layer are composed of catalyst particles with different average diameters. Compared with Example 6, the conversion rate and selectivity of Comparative Example 8 are reduced.

[0182] The preferred embodiments of the present application are described in detail above. However, the present application is not limited to the specific details of the above embodiments. Within the technical concept of the present application, various simple modifications can be made to the technical solution of the present application, and these simple modifications all fall within the scope of protection of the present application.

[0183] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner unless there is any contradiction. In order to avoid unnecessary repetition, this application will not further describe various possible combinations.

[0184] In addition, the various implementation methods of the present application can be arbitrarily combined, as long as they do not violate the concept of the present application, they should also be regarded as the content of the invention of the present application.

Claims

1. A gas distribution unit, comprising at least one gas distribution pipe, wherein the at least one gas distribution pipe comprises from top to bottom at least one gas outlet A and at least one gas outlet B, wherein the gas outlet A sprays gas downward at an injection angle εA, and the gas outlet B sprays gas downward at an injection angle εB, wherein the injection angle is the angle between the gas injection direction and the vertical direction, and εA>εB.

2. The gas distribution unit according to claim 1, characterized in that εA and εB are 10-85°, preferably 20-65°; Preferably, the difference between εA and εB is 5-60°, preferably 5-45°.

3. The gas distribution unit according to claim 1 or 2, characterized in that: The gas outlet A and the gas outlet B are located on the same or different gas distribution pipes, Preferably, the gas outlet A and the gas outlet B are located on different gas distribution pipes, wherein the gas outlet A is located on a first gas distribution pipe and the gas outlet B is located on a second gas distribution pipe. More preferably, the first and second gas distribution pipes are horizontally arranged.

4. The gas distribution unit according to claim 3, characterized in that A plurality of the first and second gas distribution pipes are connected to form a gas distributor, Preferably, a plurality of the first gas distribution pipes are connected to form a first gas distributor, and a plurality of the second gas distribution pipes are connected to form a second gas distributor, wherein the first and second gas distributors are respectively arranged horizontally, and preferably the first and second gas distributors each include a horizontally arranged straight pipe-shaped main pipe and one or more straight pipe-shaped branches connected to the main pipe, and the two main pipes of the first and second gas distributors are parallel to each other, and the projections of the two main pipes on the horizontal plane have an angle δ, and the range of δ is 0°-135°, preferably 20°-70°; More preferably, the first and second gas distribution pipes are respectively straight pipes with circular cross-sections, and the gas outlet A is an opening on the first gas distribution pipe, and the gas outlet B is an opening on the second gas distribution pipe, wherein the opening angles αA and αB are respectively equivalent to the gas injection angles εA and εB, wherein the opening angle is the angle between the center point of the opening cross section and the straight line where the center point of the cross-section circle of the corresponding gas distribution pipe is located and the vertical direction, preferably, there are multiple openings on the first gas distribution pipe as gas outlet A, and there are multiple openings on the second gas distribution pipe as gas outlet B, and more preferably, the first and second gas distribution pipes each have an opening rate of 1‰ to 60‰, preferably 1‰-45‰, and more preferably 5‰ to 30‰.

5. The gas distribution unit according to any one of claims 1 to 4, characterized in that: Also includes: A bottom gas distribution pipe, which is located below all of the at least one gas distribution pipes, and the bottom gas distribution pipe has at least one gas outlet D, so as to spray gas upward at a spray angle β, wherein β is 0-80°, preferably 30-60°; Preferably, a plurality of bottom gas distribution pipes are interconnected to form a bottom gas distributor.

6. The gas distribution unit according to claim 1 or 2, characterized in that: The at least one gas distribution pipe further comprises at least one gas outlet C, which is located below the gas outlet A and the gas outlet B and sprays gas downward at an injection angle εC, and εA>εB>εC, preferably, the difference between εA and εB is smaller than the difference between εB and εC; More preferably, εC is 10-65°, preferably 20-50°; Further preferably, the difference between εB and εC is 5-60°, preferably 5-45°; More preferably, the difference between εA and εB is smaller than the difference between εB and εC by 1-30°, preferably 5-25°.

7. The gas distribution unit according to claim 6, characterized in that The gas outlet A, the gas outlet B and the gas outlet C are located on the same or different gas distribution pipes, Preferably, the gas outlet A, the gas outlet B and the gas outlet C are respectively located on different gas distribution pipes, wherein the gas outlet A is located on the first gas distribution pipe, the gas outlet B is located on the second gas distribution pipe, and the at least one gas outlet C is located on the third gas distribution pipe. More preferably, the first, second and third gas distribution pipes are horizontally arranged.

8. The gas distribution unit according to claim 6 or 7, characterized in that A plurality of the first, second and third gas distribution pipes are connected to form a gas distributor, Preferably, a plurality of the first gas distribution pipes are connected to form a first gas distributor, a plurality of the second gas distribution pipes are connected to form a second gas distributor, and a plurality of the third gas distribution pipes are connected to form a third gas distributor, wherein the first, second and third gas distributors are each arranged horizontally, preferably the first, second and third gas distributors each include a main pipe in a horizontally arranged straight pipe shape and one or more branch pipes in a straight pipe shape connected to the main pipe, and more preferably the three main pipes of the first, second and third gas distributors are parallel to each other, and the projections of the three main pipes on the horizontal plane have an angle δ, and the range of δ is 0°-135°, preferably 20°-70°; More preferably, each of the first, second and third gas distribution pipes is a straight pipe with a circular cross-section. And the gas outlet A is an opening on the first gas distribution pipe, the gas outlet B is an opening on the second gas distribution pipe, and the at least one gas outlet C is an opening on the third gas distribution pipe, wherein the opening angles αA, αB, αC are respectively equivalent to the gas injection angles εA, εB, εC, wherein the opening angle is the angle between the center point of the opening cross section and the straight line where the center point of the cross-sectional circle of the corresponding gas distribution pipe is located and the vertical direction. Preferably, there are multiple openings on the first gas distribution pipe as gas outlet A, there are multiple openings on the second gas distribution pipe as gas outlet B, and there are multiple openings on the third gas distribution pipe as gas outlet C. More preferably, the first, second and third gas distribution pipes each have an opening rate of 1‰ to 60‰, preferably 1‰-45‰, and more preferably 5‰ to 30‰.

9. The gas distribution unit according to any one of claims 6 to 8, characterized in that: Also includes A bottom gas distribution pipe, which is located below all of the at least one gas distribution pipes and sprays gas upward at a spray angle β, wherein β is 0-80°, preferably 30-60°; Preferably, a plurality of bottom gas distribution pipes are interconnected to form a bottom gas distributor.

10. A bubbling bed reactor, characterized in that: comprising the gas distribution unit according to any one of claims 1 to 4, Preferably, the height of the gas outlet A in the bubbling bed reactor is hA, and the height of the gas outlet B in the bubbling bed reactor is hB, wherein hA and hB are 10-90%, preferably 20-85%, of the total height H of the bubbling bed reactor; Preferably, the difference between hA and hB is 5-70%, preferably 10-60%, of the total height H of the bubbling bed reactor.

11. The bubbling bed reactor according to claim 10, characterized in that: The bubbling bed reactor further comprises at least one catalyst bed layer, wherein the at least one catalyst bed layer is composed of catalyst particles, wherein the first and second gas distribution pipes are independently located in the at least one catalyst bed layer, Preferably, the first and second gas distribution pipes are respectively located in the first and second catalyst beds, and preferably, the first and second catalyst beds are each composed of catalyst particles, wherein the average particle sizes of the catalyst particles in the first and second catalyst beds are P1 and P2, respectively, and P1>P2; More preferably, the bubbling bed reactor further comprises at least one bottom gas distributor, which is located below each catalyst bed or below all catalyst beds, wherein the bottom gas distributor is formed by connecting a plurality of bottom gas distribution pipes and the bottom gas distribution pipes include a gas outlet. The port sprays gas upward at a spray angle β, wherein β is 0-80°, preferably 30-60°.

12. A bubbling bed reactor, characterized in that: comprising a gas distribution unit as claimed in any one of claims 6 to 8, Preferably, the height of the gas outlet A in the bubbling bed reactor is hA, the height of the gas outlet B in the bubbling bed reactor is hB, and the height of the gas outlet C in the bubbling bed reactor is hC, preferably hA, hB and hC are 10-90% of the total height H of the bubbling bed reactor, preferably 20-85%; More preferably, the difference between hA and hB is 5-70%, preferably 10-60%, of the total height H of the bubbling bed reactor, and the difference between hB and hC is 5-60%, preferably 10-50%, of the total height H of the bubbling bed reactor, wherein the difference between hB and hC is the same as or different from the difference between hA and hB.

13. The gas distribution unit according to claim 12, characterized in that The bubbling bed reactor further comprises at least one catalyst bed layer, wherein the at least one catalyst bed layer is composed of catalyst particles, wherein the first, second and third gas distribution pipes are independently located in the at least one catalyst bed layer, Preferably, the first, second and third gas distribution pipes are respectively located in the first, second and third catalyst beds, preferably, the first, second and third catalyst beds are each composed of catalyst particles, wherein the average particle sizes of the catalyst particles in the first, second and third catalyst beds are P1, P2 and P3 respectively, and P1>P2>P3; More preferably, the bubbling bed reactor also includes at least one bottom gas distributor, which is located below each catalyst bed or below all catalyst beds, and the bottom gas distributor is formed by connecting a plurality of bottom gas distribution pipes, and the bottom gas distribution pipes include a gas outlet to spray gas upward at an injection angle β, wherein β is 0-80°, preferably 30-60°.

14. The bubbling bed reactor according to any one of claims 10 to 13, characterized in that: Also includes: A liquid distribution pipe, the height of which in the bubbling bed reactor is greater than the height of all the at least one gas distribution pipes in the bubbling bed reactor, and greater than the height of all the at least one catalyst bed in the bubbling bed reactor, and which inputs the liquid raw material into the bubbling bed reactor; Preferably, a plurality of liquid distribution pipes are interconnected to form a top liquid distributor.

15. A reaction method, characterized in that: The method comprises the steps of: using the gas distribution unit as claimed in any one of claims 1 to 9 to inject the gas reactant into the bubbling bed reactor to react with the liquid reactant therein.

16. The reaction method according to claim 15, characterized in that The reaction method is used for synthesizing ethylene carbonate, propylene carbonate or butylene carbonate, the liquid reactant is ethylene oxide, propylene oxide or butylene oxide respectively, and the gas reactant is carbon dioxide.

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