Patent Description:
The present disclosure relates to the field of petrochemical industry, in particular to a catalytic reaction unit and a reactive distillation column using the catalytic reaction unit.

Catalytic distillation originated from the chemical industry, is used to accomplish catalytic reaction and distillation operations in the same container, and it has advantages such as energy saving, high efficiency and high economic efficiency, etc. The catalytic distillation technique has been widely applied in the chemical industry owing to its advantages. Early in the <NUM>, American enterprises began to use the ideal of catalytic distillation to solve the problem that it was difficult to separate mixtures containing normal olefins, isomeric olefins and alkanes by conventional distillation because of the similar boiling points. Later, based on the characteristics of different reactions, various catalytic distillation apparatuses came into being. For example, there are catalytic distillation apparatuses having a difunctional structure, in which a distillation function is arranged on the left, while a reaction function is arranged on the right, i.e., a left chamber has a distillation function, and is equipped with distillation plates; a right chamber has a reaction function, and is filled with a catalyst required for the reaction, and the left chamber and the right chamber are separated from each other by a partition. For another example, there are catalytic distillation apparatuses having a vertical structure, which are more common; here, the vertical structure refers to the relative arrangement of the reaction zone and the distillation zone. A catalytic distillation apparatus having a vertical structure for preparing methanol from a synthetic gas has been disclosed in the US Patent Application No. <CIT>. The apparatus has a plurality of fixed bed layers therein, and the diameter of the reaction zone may vary at different heights; whether the reaction zone is filled with a catalyst and the thickness of the filled catalyst can be determined according to the actual circumstance; an external heat exchanger, a dehydration device, or a paraffin separation device and reflux side lines may be arranged at the side lines at different positions; and the outside of the entire catalytic distillation apparatus may be surrounded by a separate cooling device. Another example of a catalytic reaction unit is provided in <CIT>.

In view of the existence of gas phase components in the product, a concept of gas channel is put forward in the industry to enable the gas to pass through the catalyst bed layers more easily. For example, a gas channel may be embedded in the middle part of the catalytic distillation apparatus. The gas passage enables the gas phase in the lower bed layer to directly go to the upper distillation plate layer for mass transfer without being blocked by the catalyst bed layer. Alternatively, a plurality of gas channels may be arranged in the catalytic distillation apparatus. A catalytic distillation column is a columnar outer cylinder that is closed at the top and the bottom, with a plurality of cylindrical gas channels perpendicular to the cross section arranged therein; the gas channels are embedded in the reaction zone, and the terminals of the channels are in communication with the open areas of a rectifying section and a stripping section or the media in these sections; the outer cylinder of the reaction zone is filled with a high-density catalyst, and the wall of the inner cylinder may be perforated to enable close contact with the catalyst.

In summary, the existing catalytic distillation technique itself improves the reaction efficiency and the separation of the product. In the application of the catalytic distillation technique, there are various forms of reactors and internal components inside the reactors. However, it is necessary to further improve the efficiency of the existing reactors and internal components; especially, the problem of separating the gas phase reaction product from the reaction zone timely still can't be solved effectively in the prior art. Therefore, there is an urgent need for a catalytic reaction unit and a distillation column using the catalytic reaction unit that have solved the separation efficiency problem in the prior art. In addition, with the catalytic reaction unit and the distillation column, the gas phase product can still be separated efficiently even if the gas phase product has secondary reactions.

The information disclosed in this section is only intended to make the background of the present disclosure understood better, and should not be deemed as acknowledging or implying in any form that the information constitutes the prior art well known to those having ordinary skills in the art.

An object of the present disclosure is to provide a catalytic reaction unit and a distillation column using the catalytic reaction unit, so as to overcome the drawback that the gas phase reaction product can't be separated timely from the reaction zone in the prior art; especially, with the catalytic reaction unit and the distillation column, the gas phase product can still be separated efficiently even if the gas phase product has secondary reactions.

To attain the object described above, in a first aspect, the present disclosure provides a catalytic reaction unit, which comprises:
a plurality of catalyst bed layers arranged vertically, each of the catalyst bed layers being filled with a solid catalyst (<NUM>) respectively, and an inclined surface on an upper part of the corresponding solid catalyst (<NUM>) being arranged between adjacent catalyst bed layers, wherein the inclined surface as a whole is an umbrella-shaped partition (<NUM>), the solid catalyst (<NUM>) is supported by a liquid receiving tray (<NUM>), a tail end of the umbrella-shaped partition (<NUM>) is provided with an annular downcomer, and the bottom of the annular downcomer is spaced apart from the liquid receiving tray (<NUM>) by a certain distance, so that the liquid phase feed enters the catalyst bed layer in a radial direction;.

Preferably, the liquid phase feeding subunit comprises: a liquid phase feed pipe extending in the radial direction of the catalytic reaction unit; and a liquid phase distribution pipe, which is annular and orthogonal or tangential to the liquid phase feed pipe, wherein a pipe wall of the liquid phase distribution pipe is provided with a plurality of pores for uniformly distributing the liquid phase feed to the annular downcomer in all directions.

Preferably, the liquid-sealing baffle comprises: a horizontal part, which is in an annular flat plate shape and disposed above the overflow weir; and a vertical part, which is in a cylindrical shape and is integrally formed with the horizontal part, with a lower end of the vertical part spaced apart from the bottom of the catalyst bed layer by a certain distance.

Preferably, the top edge of the overflow weir is higher than the top surface of the catalyst in the bed layer by <NUM>-<NUM>.

Preferably, the gas phase feeding subunit comprises: a gas phase feed pipe extending in the radial direction of the catalytic reaction unit; and a gas phase distribution pipe, which is in an annular shape or multi-layer concentric ring shape, and is orthogonal or tangential to the gas phase feed pipe, with a wall surface of the gas phase distribution pipe provided with a plurality of pores for uniformly distributing the gas phase feed to the bottom of the catalyst bed layer in all directions.

Preferably, the gas phase feeding subunit further comprises: a gas phase distribution disk, which is disposed at the bottom of the catalyst bed layer and is generally in a disk shape, with a plurality of pores distributed uniformly and densely in the gas phase distribution disk.

Preferably, the gas phase distribution pipe is disposed below or inside the catalyst bed layer.

Preferably, the gas phase channel is disposed in the middle of the catalytic reaction unit and extends through all the catalyst bed layers from bottom to top.

Preferably, the height of each catalyst bed layer is set to <NUM> - <NUM>,<NUM>.

In the above technical scheme, the top edge of the overflow weir may be higher than the top surface of the catalyst in the bed layer by <NUM>-<NUM>. The gas phase distribution pipe may be disposed below or inside the catalyst bed layer.

In another aspect, the present disclosure provides a reactive distillation column using the aforesaid catalytic reaction unit, wherein the reactive distillation column has a multi-layer plate tower structure. The reactive distillation column is applicable to a reaction system in which at least one liquid phase feed and at least one gas phase feed have chemical reactions on a solid catalyst and at least one of the reaction products is a gas phase product.

Compared with the prior art, the present disclosure attains the following beneficial effects:.

The above description is only a summary of the technical scheme of the present disclosure. Hereunder one or more preferred embodiments will be presented and described with reference to the accompanying drawings in detail, in order to make the technical means of the present disclosure understood more clearly and implemented on the basis of the description, and make the above-mentioned and other objects, technical features and advantages of the present disclosure understood more easily.

Hereunder some specific embodiments of the present disclosure will be detailed with reference to the accompanying drawings. However, it should be understood that the scope of protection of the present disclosure is not limited to those embodiments.

Unless otherwise expressly stated, throughout the specification and claims, the term "comprise" or "include" or their variants such as "comprising" or "including" shall be understood as including the enumerated elements or components, without excluding other elements or components.

In this document, for the convenience of description, spatially relative terms such as "underside", "below", "bottom", "upside", "above", and "top", etc., may be used to describe the relationship between one element or feature and another element or feature in the drawings. It should be understood that the spatially relative terms are intended to include different directions of the objects in use or operation other than the directions depicted in the drawings. For example, if an object in a drawing is turned upside down, an element described as "below" or "downside" other elements or features will be oriented "above" the elements or features. Therefore, the exemplary term "below" may include "below" and "above" directions. Objects may also have other orientations (rotated by <NUM> degrees or other orientations), and the spatially relative terms used herein should be interpreted accordingly.

In this document, the terms "first", "second", etc. are used to distinguish two different elements or parts, rather than to define a specific position or relative relationship. In other words, in some embodiments, the terms "first", "second", etc. may also be interchanged with each other.

As shown in <FIG>, the catalytic reaction unit in the present disclosure is an internal component of a reactive distillation column <NUM>, and comprises a plurality of catalyst bed layers, a liquid phase feeding subunit, a gas phase feeding subunit, and a gas phase channel. The catalytic reaction unit may be provided with two or more catalyst bed layers, each of which is filled with a solid catalyst <NUM>, an inclined surface on the upper part of the corresponding solid catalyst <NUM> (i.e., the solid catalyst in the lower catalyst bed layer) is arranged between adjacent catalyst bed layers, the inclined surface may be generally in an umbrella shape and serves as a partition, which can separate the gas phase feed from the product gas between adjacent catalyst bed layers on one hand, and guides the liquid phase flow and the gas phase flow on the other hand; preferably, but not limitingly, the surface of the umbrella may be in an arc shape, or the umbrella may be a telescopic umbrella. The liquid phase feeding subunit is arranged above the inclined surface (i.e., the umbrella-shaped partition <NUM>) of the topmost catalyst bed layer, a liquid phase feed is guided by the inclined surface of the umbrella-shaped partition <NUM> to the catalyst bed layer and contacts with the solid catalyst <NUM>; specifically, the tail end of the umbrella-shaped partition <NUM> is provided with an annular outer downcomer <NUM> (i.e., the annular space between the downcomer flap <NUM> and the inner wall surface of the reactive distillation column <NUM> in <FIG>), and the bottom of the outer downcomer <NUM> is spaced apart from the bottom of the catalyst bed layer by a certain distance, so that the liquid phase feed enters the catalyst bed layer in the radial direction of the reactive distillation column <NUM>. A gas phase feeding subunit is arranged at each catalyst bed layer; specifically, the gas phase feeding subunit is arranged between the catalyst bed layer of an upper layer and the umbrella-shaped partition <NUM> of the next layer, and the gas phase feed at each layer enters the catalyst bed layer upwardly. After the gas phase feed and the liquid phase feed react fully in the presence of the solid catalyst <NUM> in a catalyst bed layer, the gas phase product in each layer is guided along the lower part of the umbrella-shaped partition <NUM> to a gas phase channel <NUM>. The gas phase channel <NUM> is relatively isolated from the gas phase feeding subunit, i.e., the gas phase product generated by reaction of the gas phase feed to the liquid phase feed in the catalyst bed layer directly enters the gas phase channel <NUM>. The gas phase channel is located in the middle of the reactive distillation column <NUM>, and extends through all the catalyst bed layers from bottom to top.

Furthermore, as shown in <FIG> and <FIG>, the liquid phase feeding subunit further comprises a liquid phase feed pipe <NUM> and a liquid phase distribution pipe <NUM>. The liquid phase feed pipe <NUM> extends in the radial direction of the catalytic reaction unit, is annular, and is orthogonal or tangential to the pipe body <NUM> of the liquid phase distribution pipe <NUM>; the pipe wall of the liquid phase distribution pipe <NUM> is provided with a plurality of pore channels <NUM> for uniformly distributing the liquid phase feed to the annular outer downcomer <NUM> in all directions. The openings of the pore channels <NUM> may be in the top surface, bottom surface, and side surface of the pipe body in various directions. The liquid phase feed enters the reactive distillation column <NUM> through the liquid phase feed pipe <NUM>, is distributed through the annular liquid phase distribution pipe <NUM> into the tower, flows via the umbrella-shaped partition <NUM> to the periphery and into the outer downcomer <NUM>, and then enters into the catalyst bed layer horizontally to contact with the solid catalyst <NUM>. The feeding direction of the liquid phase feed pipe <NUM> is the radial direction of the reactive distillation column and orthogonal or tangential to the radial direction of the annular liquid phase distribution pipe <NUM>; the ring diameter of the annular liquid phase distribution pipe <NUM> is greater than the outer diameter of the gas phase channel <NUM> but smaller than the inner diameter of the reactive distillation column <NUM>; and the pipe wall of the annular liquid phase distribution pipe <NUM> is provided with several pores to facilitate distributing the liquid phase feed uniformly in all directions of the outer downcomer <NUM>. The height of the downcomer flap <NUM> is usually smaller than the catalyst packing height in the layer, and the distance of the downcomer flap <NUM> from the inner wall of the reactive distillation column <NUM> is determined according to the flow rate of the liquid-phase reactant in the layer.

Furthermore, as shown in <FIG>, the catalyst bed layers in the reactive distillation column <NUM> may have the same height or different heights, depending on the specific chemical reaction system; the top part of each catalyst bed layer is fixed with a mesh to keep the bed layer relatively stable, and the height of the bed layers is set to <NUM> - <NUM>,<NUM>. Each catalyst bed layer is provided with an overflow weir <NUM> and a liquid-sealing baffle <NUM>, and the overflow weir <NUM> is disposed at the side near the gas phase channel <NUM>. The liquid-sealing baffle <NUM> is disposed at the upper part of the overflow weir <NUM> and configured to isolate the gas phase feed from the gas phase product. Furthermore, the liquid-sealing baffle <NUM> comprises a horizontal part and a vertical part, wherein the horizontal part is in an annular flat plate shape and disposed above the overflow weir <NUM>; the vertical part is in a cylindrical shape, and is integrally formed with the horizontal part or otherwise seamlessly connected to the horizontal part; the lower end of the vertical part is spaced apart from the bottom of the catalyst bed layer by a certain distance to ensure the outflow of the liquid phase product. The unreacted liquid phase feed and the material that has reacted but remains in the liquid phase in the catalyst bed layer flow through the overflow weir <NUM> and the inner downcomer <NUM> (i.e., an annular space between the overflow weir <NUM> and the outer wall of the gas phase channel <NUM>), and flow along the umbrella-shaped partition <NUM> through the outer downcomer <NUM> of the next layer and enter the next catalyst bed layer. The overflow weir <NUM> is higher than the top flat surface of the catalyst in the bed layer, preferably is higher by <NUM>-<NUM>. The spacing of the annular inner downcomer <NUM> formed between the overflow weir <NUM> and the outer wall of the gas phase channel <NUM> may be determined according to the liquid phase load, and the downcomer of each bed layer may have the same dimensions or different dimensions.

Furthermore, as shown in <FIG> and <FIG>, the gas phase feeding subunit comprises a gas phase feed pipe <NUM> and a gas phase distribution pipe <NUM>, wherein the gas phase feed pipe <NUM> extends in the radial direction of the reactive distillation column <NUM>; the gas phase distribution pipe <NUM> is in an annular shape (see <FIG> and <FIG>) or multi-layer concentric ring shape (see the two-layer concentric ring in <FIG>); the gas phase feed pipe <NUM> is orthogonal to the pipe body <NUM> of the gas phase distribution pipe <NUM> (see <FIG>) or tangential to the pipe body <NUM> of the gas phase distribution pipe <NUM> (see <FIG>); the wall surface of the gas phase distribution pipe <NUM> is provided with a plurality of pore channels <NUM> for uniformly distributing the gas phase feed to the bottom of the catalyst bed layer in all directions. Preferably, but not limitingly, the gas phase distribution pipe <NUM> may be disposed below or inside the catalyst bed layer. Furthermore, as shown in <FIG>, the gas phase feeding subunit further comprises a gas phase distribution disk <NUM>, which is disposed at the bottom of the catalyst bed layer and is generally in a disk shape, and a plurality of pores <NUM> are distributed uniformly and densely in the gas phase distribution disk. The gas phase feed enters the reactive distillation column <NUM> through the gas phase feed pipe <NUM> in each layer, is distributed through the annular gas phase distribution pipe <NUM> into the reactive distillation column <NUM>, and enter upward through the gas phase distribution disk <NUM> at the lower part of the catalyst supporting tray <NUM> into the catalyst bed layer. The gas phase feed pipe <NUM> enters the reactive distillation column <NUM> in the radial direction, and is orthogonal or tangential to the annular gas phase distribution pipe <NUM>; the annular gas phase distribution pipe <NUM> is disposed below the catalyst bed layer, the ring diameter of the annular gas phase distribution pipe <NUM> is smaller than the diameter of the outer ring of the catalyst bed layer, the inner diameter of the annular gas phase distribution pipe <NUM> is greater than the diameter of the inner ring of the catalyst bed layer, and the pipe wall of the annular gas phase distribution pipe <NUM> is provided with several pore channels <NUM> to facilitate distributing the gas uniformly to all positions of the gas phase distribution disk <NUM>. The main function of the catalyst supporting tray <NUM> is to support the catalyst bed layer and ensure that the catalyst bed layer is kept stable in the axial direction of the reactive distillation column. The function of the gas phase distribution disk <NUM> is to ensure uniform distribution of the gas phase feed and avoid direct leakage of the liquid phase feed on the catalyst bed layer as far as possible (with the gas phase distribution disk <NUM> in the present disclosure, the liquid leakage is less than <NUM>%). The distribution of the gas phase feed will be more uniform if two or more annular gas phase distribution pipes <NUM> that are concentric but have different diameters are arranged in the same plane. In the embodiment shown in <FIG>, the annular gas phase distribution pipe <NUM> is disposed below the catalyst bed layer; in the case that the annular gas phase distribution pipe <NUM> is mounted inside the catalyst bed layer, the catalyst supporting tray <NUM> may be modified from the grating <NUM> in <FIG> to a supporting plate, and the gas phase distribution disk <NUM> may be omitted at the same time.

In the catalyst bed layer of the catalytic reaction unit in the present disclosure, the liquid phase feed and the gas phase feed have a catalytic reaction, the gas-phase product and the unreacted gas phase feed rise up through the gas phase channel <NUM> and escape from the reaction system, and the gas phase product generated after the chemical reaction of the reactants in the catalyst bed layer leaves the reaction zone timely and doesn't enter the upper catalyst bed layer (isolated by the umbrella-shaped partition), thereby any secondary reaction of the target product is avoided, and the selectivity of the reaction is improved. Besides, since the gas-phase product in the reaction zone leaves the reaction zone timely, the driving force of the reaction is increased, and the equilibrium conversion ratio is improved.

The reactive distillation column in the present disclosure uses the catalytic reaction unit described above, and the reactive distillation column <NUM> may have a multi-layer plate tower structure. Two or more catalyst bed layers may be provided in the reactive distillation column. The reactive distillation column <NUM> in the present disclosure is applicable to a reaction system in which at least one liquid phase feed and at least one gas phase feed have chemical reactions on a solid catalyst and at least one of the reaction products is a gas phase product, for example, hydrocracking of petroleum fractions and chemical synthetic oils, hydro-dewaxing of diesel and lube oil distillates, and hydrotreating of various petroleum fractions, etc..

In the reactive distillation column <NUM> in the present disclosure, each column tray is provided with a liquid-sealing baffle connected to the gas phase channel, besides the downcomer, the overflow weir and the liquid receiving tray <NUM>; adjacent column trays are separated by an umbrella-shaped partition; and each layer of column tray has an annular structure, with an inner edge connected to the gas phase channel and an outer edge connected to the inner wall of the reactive distillation column. The gas phase channel is a common channel for transporting out the gas-phase product generated in the chemical reaction on each layer of column tray. In the embodiment of the present disclosure, all liquid phase feed positions are arranged at the upper part of one layer of column tray or arranged on some or all layers of column trays; and a gas phase feed position is arranged at the bottom of each layer. The space above each layer of column tray is a catalyst loading area, the liquid phase feed flows through the catalyst bed layer in the radial direction, the gas phase feed enters the reactive distillation column <NUM> from the bottom of the column tray, and the liquid phase feed and the gas phase feed react under the action of the catalyst; the gas phase material generated through the reaction directly leaves the reaction system and enters the gas phase channel in the middle part, the liquid phase material leaves the bed layer and then enters the next bed layer through the downcomer, and may be discharged through a drain port (not shown) arranged at the bottom of the reactive distillation column <NUM>. Since the reaction and the separation happen at the same time, the reaction equilibrium can be destroyed, and the conversion efficiency of the reactants and the selectivity of the target product can be improved effectively.

The catalytic reaction unit in the present disclosure is applied in a hydrocracking reactor for the catalytic hydrocracking process of diesel oil, and a pre-refining reactor is connected in series upstream of the cracking reactor process for removing the impurities in the raw oil. The catalyst is the same catalyst applied in similar industrial apparatuses. The yield of the gasoline fraction in the cracked product is <NUM>%, the gasoline octane number RON is <NUM>, and the liquid yield is <NUM>%.

The catalytic reaction unit in the present disclosure is applied in a hydrocracking reactor for the catalytic hydrocracking process of diesel oil, and a pre-refining reactor is connected in series upstream of the cracking reactor process for removing the impurities in the raw oil. The catalyst is the same catalyst applied in similar industrial apparatuses, and is fixed on the bed layers with a stainless steel mesh. The yield of the gasoline fraction in the cracked product is <NUM>%, the gasoline octane number RON is <NUM>, and the liquid yield is <NUM>%.

The catalytic reaction unit in the present disclosure is applied in a hydrocracking reactor for the catalytic hydrocracking process of diesel oil, and a pre-refining reactor is connected in series upstream of the cracking reactor process for removing the impurities in the raw oil. The catalyst is the same catalyst applied in similar industrial apparatuses, and is fixed on the bed layers with a stainless steel mesh. The yield of the gasoline fractions is <NUM>%, the gasoline octane number RON is <NUM>, and the liquid yield is <NUM>%.

The catalytic reaction unit in the present disclosure is applied in a hydrocracking reactor for the catalytic hydrocracking process of VGO, and a pre-refining reactor is connected in series upstream of the cracking reactor process for removing the impurities in the raw oil. The catalyst is the same catalyst applied in similar industrial apparatuses, and is fixed on the bed layers with a stainless steel mesh. The yield of the heavy naphtha fraction is <NUM>%, the aromatic content in the heavy naphtha is <NUM>%, and the liquid yield is <NUM>%.

Claim 1:
A catalytic reaction unit, comprising:
a plurality of catalyst bed layers arranged vertically, each of the catalyst bed layers being filled with a solid catalyst (<NUM>) respectively, and an inclined surface on an upper part of the corresponding solid catalyst (<NUM>) being arranged between adjacent catalyst bed layers, wherein the inclined surface as a whole is an umbrella-shaped partition (<NUM>), the solid catalyst (<NUM>) is supported by a liquid receiving tray (<NUM>), a tail end of the umbrella-shaped partition (<NUM>) is provided with an annular downcomer, and the bottom of the annular downcomer is spaced apart from the liquid receiving tray (<NUM>) by a certain distance, so that the liquid phase feed enters the catalyst bed layer in a radial direction;
a liquid phase feeding subunit, which is arranged above a topmost catalyst bed layer, so that a liquid phase feed can be introduced into the catalyst bed layer, and the liquid phase feed is guided by the inclined surface to sequentially enter each catalyst bed layer from top to bottom;
a gas phase feeding subunit, which is arranged between the catalyst bed layer of an upper layer and the inclined surface of the next layer, a gas phase feed of each layer entering the catalyst bed layer in an upward manner; and
a gas phase channel (<NUM>), which is relatively isolated from the gas phase feeding subunit, and a gas phase product generated by reaction of the gas phase feed to the liquid phase feed in the catalyst bed layer directly entering the gas phase channel (<NUM>),
wherein the gas phase channel (<NUM>) is disposed in the middle of the catalytic reaction unit and extends through all the catalyst bed layers from bottom to top, and the catalyst bed layer is provided with:
an overflow weir (<NUM>) arranged at a side near the gas phase channel (<NUM>); and
a liquid-sealing baffle (<NUM>) arranged at the upper part of the overflow weir (<NUM>) and configured to isolate the gas phase feed from the gas phase product.