Filtration recovery system and process system for continuous catalytic hydrogenation reaction

Abstract

The present disclosure relates to a filtering and recovery system and a process system for continuous catalytic hydrogenation reaction. The filtering and recovery system includes: a first shunt pipeline, whose inlet is connected to a circulation loop, and the circulation loop is a loop formed by connecting the feed port and the discharge port of a reactor for catalytic hydrogenation reaction; a first reflux pipeline, whose outlet is connected to the circulation loop; and a first filtering device, including a first filtering element, a first feed port, a first discharge port and a second discharge port, the outlet of the first shunt pipeline is connected to the first feed port, and the inlet of the first reflux pipeline is connected to the second discharge port, the first filtering element is used to filter the material entering the first filtering device to form a first clear liquid and a first concentrated liquid, the first discharge port is used to discharge the first clear liquid, and the second discharge port is used to discharge the first concentrated liquid. Through the filtering and recovery system, the difficulty of material filtering can be reduced, and the problem of easy clogging of the filtering device can be improved or avoided.

Description

Technical Field

[0001] The present disclosure relates to the field of separation technology, and in particular, to a filtering recovery system and a process system for continuous catalytic hydrogenation reaction. Background Art

[0002] As an important organic chemical raw material, methylaniline plays an important role in many industries such as dyes, plastics, medicines and rubber. At present, methylaniline is mainly produced by catalytic hydrogenation of nitrotoluene in industry.

[0003] The process system for catalytic hydrogenation reaction includes a reactor, in which nitrotoluene and hydrogen generate methylaniline and water under the action of a catalyst. The process system also includes a filtering device for filtering and recovering the catalyst in the reaction product to obtain a clear liquid. The clear liquid is subsequently separated and purified to obtain the final methylaniline product.

[0004] However, the proportion of catalyst added in the reactor is relatively high, and the entire process system is in a high-speed circulation state, which makes the processing capacity of the filter device quite large when separating the product and catalyst in the material, resulting in extremely high difficulty in separating the catalyst and easily causing clogging of the filter device. Summary of the invention

[0005] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

[0006] The purpose of the present disclosure is to provide a filtering recovery system and a process system for continuous catalytic hydrogenation reaction that can reduce the difficulty of material separation and improve the problem of easy clogging of the filtering device.

[0007] In order to achieve the above object, according to a first aspect of the present disclosure, a filtering recovery system is provided, comprising:

[0008] A first branch pipeline, the inlet of which is connected to a circulation loop, wherein the circulation loop is a loop formed by connecting a feed inlet and a discharge outlet of a reactor for performing a catalytic hydrogenation reaction;

[0009] A first reflux pipeline, an outlet of which is connected to the circulation loop; and

[0010] The first filter device includes a first filter element, a first feed port, a first discharge port, and a second discharge port. The outlet of the first diversion pipeline is connected to the first feed port, and the inlet of the first reflux pipeline is connected to the second discharge port. The first filter element is used to filter the material entering the first filter device to form a first clear liquid and a first concentrated liquid. The first discharge port is used to discharge the first clear liquid, and the second discharge port is used to discharge the first concentrated liquid.

[0011] In some embodiments, the second discharge port may be configured to continuously discharge the first concentrated solution, so that the first concentrated solution continuously flows back to the circulation loop.

[0012] In some embodiments, the first filter device may further include a first liquid stabilizing device, which is arranged upstream of the first filter element to reduce turbulence of the material to be introduced into the first filter element.

[0013] In some embodiments, the first liquid stabilizing device may include a plurality of flow channel holes, and the plurality of flow channel holes are arranged so that the material passing through the first liquid stabilizing device flows toward the first filter element in the same flow direction.

[0014] In some embodiments, each of the plurality of flow channel holes may have a smooth inner surface.

[0015] In some embodiments, the first liquid stabilizing device may be in a flat plate shape, a conical shape, or an arc shape.

[0016] In some embodiments, the amount of material diverted from the first diversion line can be configured to account for 0.1% to 20% of the amount of material in the circulation loop, and the amount of the first concentrate refluxed from the first return line can be configured to account for 3% to 50% of the amount of material diverted from the first diversion line.

[0017] In some embodiments, the filtration recovery system may further include a second filtration device, the second filtration device including a second filter element, a second feed port, a third discharge port and a fourth discharge port, the filtration accuracy of the second filtration device is higher than the filtration accuracy of the first filtration device, the second feed port is connected to the first discharge port, the second filter element is used to filter the first clear liquid entering the second filtration device to form a second clear liquid and a second concentrated liquid, the third discharge port is used to discharge the second clear liquid, and the fourth discharge port is used to discharge the second concentrated liquid.

[0018] In some embodiments, the filtration recovery system may further include a catalyst recovery tank, and the fourth outlet is connected to the catalyst recovery tank.

[0019] In some embodiments, the filtration recovery system may also include a second diversion line and a second return line, the inlet of the second diversion line is connected to the circulation loop and the outlet is connected to the second feed port of the second filtration device, and the inlet of the second return line is connected to the fourth discharge port and the outlet is connected to the circulation loop.

[0020] In some embodiments, the filtration recovery system may further include a control device and a cleaning device, which are communicatively connected to each other, and the control device is configured to control the cleaning device to automatically clean the first filter element according to the pressure difference between the upstream and downstream of the first filter element.

[0021] In some embodiments, the cleaning device may be configured to perform at least one of backwash cleaning and power wave cleaning.

[0022] In some embodiments, the material may be a material for preparing methylaniline, diaminotoluene or o-chloroaniline by catalytic hydrogenation.

[0023] According to a second aspect of the present disclosure, a process system for continuous catalytic hydrogenation reaction is provided, comprising:

[0024] a reactor for carrying out a catalytic hydrogenation reaction therein; and

[0025] According to the filtration recovery system of any one of the embodiments of the first aspect of the present disclosure, the first branch line and the first reflux line of the filtration recovery system are connected to a circulation loop formed by connecting the feed port and the discharge port of the reactor.

[0026] According to the above technical solution, by adopting the design of split flow filtration, the amount of material passing through the filter device can be effectively reduced, thereby reducing the amount of material that the filter device needs to process per unit time, thereby reducing the difficulty of filtration, improving or avoiding the problem of easy clogging of the filter device, and facilitating the filtration recovery system to achieve long-term stable operation. In addition, the concentrated solution containing a large amount of catalyst can be continuously returned to the circulation loop, so that the catalyst can be continuously recycled, which is further conducive to the filtration recovery system to achieve long-term stable operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The features and advantages of the embodiments of the present disclosure will become more easily understood through the following description with reference to the accompanying drawings. The drawings are not drawn to scale and some features may be exaggerated or reduced to show details of particular components.

[0028] Figure 1 is a schematic diagram of a filtration recovery system according to an embodiment of the present disclosure.

[0029] Figure 2 is a schematic diagram of a filtration recovery system according to another embodiment of the present disclosure.

[0030] Figure 3 It is a schematic diagram of a filtration recovery system according to another embodiment of the present disclosure.

[0031] Figure 4 It is a schematic diagram of a filtration recovery system according to yet another embodiment of the present disclosure.

[0032] Figure 5 Schematic diagram of a first liquid stabilizing device in the shape of a flat plate.

[0033] Figure 6Schematic diagram of a first liquid stabilizing device in the shape of a flat plate with a central hole.

[0034] Figure 7 Schematic diagram of a first liquid stabilizing device in a conical shape.

[0035] Figure 8 Schematic diagram of a first liquid stabilizing device having a conical shape and a central hole.

[0036] Fig. 9 It is a schematic diagram of a first liquid stabilizing device in an arc shape.

[0037] Fig.10 It is a schematic diagram of a first liquid stabilizing device having an arc shape and a central hole.

[0038] In the drawings, the same or corresponding technical features or components are represented by the same or corresponding reference numerals. DETAILED DESCRIPTION

[0039] The present disclosure is described in detail below with reference to the accompanying drawings by means of exemplary embodiments. It should be noted that the following detailed description of the present disclosure is only for illustrative purposes and is by no means a limitation of the present disclosure.

[0040] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the common meanings understood by those skilled in the art to which this disclosure belongs. The words "first", "second", "third", "fourth" and the like used in this disclosure do not indicate any order or importance, but are only used to distinguish similar components or objects.

[0041] In the present disclosure, it should be understood that materials refer to substances used to participate in catalytic hydrogenation reactions, which include not only reaction raw materials, but also products and by-products obtained after a period of reaction. For example, for the reaction of synthesizing methylaniline from nitrotoluene, the materials include nitrotoluene, catalysts, hydrogen and other reaction raw materials, polymers or intermediates generated during the reaction, and one or more of methylaniline generated by the reaction.

[0042] As mentioned above, a filter is required in the process system for catalytic hydrogenation to filter and recover the catalyst. However, in the related art, the reactor and the filter in the process system are usually connected to form a closed loop. In other words, all the materials leaving the reactor enter the filter for filtration. This results in the filter needing to process a considerable amount of material per unit time, which leads to greater difficulty in solid-liquid separation, and the filter is very prone to clogging, which is not conducive to the long-term stable filtration and recovery process.

[0043] To solve the above problems, refer to Figures 1 to 4According to an embodiment of the present disclosure, a filtration recovery system 10 is provided. Figures 1 to 4 In FIG. 1 , a filtration recovery system 10 and a reactor 210 for performing a catalytic hydrogenation reaction are shown.

[0044] The reactor 210 includes a feed port 211 and a discharge port 212, which are connected to form a circulation loop 20. In the circulation loop 20, the material leaves through the discharge port 212, for example, under the action of a pump 220, the material continues to flow along an external pipeline connecting the feed port 211 and the discharge port 212, and returns to the reactor 210 through the feed port 211, thereby realizing continuous catalytic hydrogenation reaction.

[0045] For example, Figure 2 As shown, the reactor 210 may further include a supply port 213 for liquid-phase reaction raw materials and a supply port 214 for solid-phase catalysts to facilitate the supply and replenishment of corresponding material components.

[0046] The filtering recovery system 10 comprises a first diversion pipeline 110 , a first return pipeline 120 and a first filtering device 130 . The first filtering device 130 comprises a first filtering element 131 , a first feed port 132 , a first discharge port 133 and a second discharge port 134 .

[0047] The inlet 111 of the first branch line 110 is connected to the circulation loop 20. For example, the inlet 111 can be at the outlet 212 of the reactor 210 or at the outlet 212 of the reactor 210. Figure 1 As shown, it is connected to the circulation loop 20 at a certain point of the external pipeline. In addition, the outlet 112 of the first branch pipeline 110 is connected to the first feed port 132 of the first filtering device 130, so that the material leaving the outlet 212 of the reactor 210 is split into two parts at the inlet 111 of the first branch pipeline 110. Specifically, one part of the material returns to the reactor 210 via the feed port 211 along the circulation loop 20, and the other part of the material flows through the inlet 111 and the outlet 112 of the first branch pipeline 110 and enters the first filtering device 130.

[0048] The first filter element 131 is used to filter the material entering the first filter device 130 to form a first clear liquid and a first concentrated liquid. The first discharge port 133 of the first filter device 130 is used to discharge the first clear liquid, and the second discharge port 134 is used to discharge the first concentrated liquid.

[0049] Specifically, the first outlet 133 is located downstream of the first filter element 131, and the second outlet 134 is located upstream of the first filter element 131. Figure 1As shown, the first discharge port 133 may be located above the first filter device 130 , and the second discharge port 134 may be located below the first filter device 130 , but is not limited thereto.

[0050] It should be understood that in the present disclosure, "clear liquid" and "concentrated liquid" are defined by the solid content in the liquid phase of the material. Specifically, "clear liquid" refers to a fluid with a very low solid content entering the downstream of the filter element, and "concentrated liquid" refers to a fluid with a relatively high solid content intercepted by the filter element upstream. Here, the solid content refers to the catalyst content.

[0051] The second discharge port 134 is connected to the inlet 121 of the first reflux pipeline 120, and the outlet 122 of the first reflux pipeline 120 is connected to the circulation loop 20, so that the first concentrated solution can be returned to the circulation loop 20 via the first reflux pipeline 120, thereby allowing the first concentrated solution and the higher concentration of catalyst in the first concentrated solution to return to the reactor 210 to continue to participate in the catalytic hydrogenation reaction.

[0052] It should be noted that, in the above case, the catalyst in the first concentrated solution can basically maintain its original state and return to the circulation loop 20, that is, the concentration, activity state and other conditions of the catalyst can remain basically consistent with the material in the circulation loop 20, so it will hardly affect the reaction process, which helps to maintain the stability of the reaction process.

[0053] By adopting the above-mentioned filtering and recycling system, the first diversion pipeline is used to divert the materials involved in the catalytic hydrogenation reaction, which can reduce the materials entering the first filtering device, thereby effectively reducing the amount of materials that need to be processed by the first filtering element per unit time, and reducing the material particle load on the first filtering element. As a result, not only can the difficulty of material separation be reduced, but also the clogging of the first filtering element is slowed down or directly avoided, reducing the risk of clogging of the first filtering device, which is conducive to the long-term stable operation of the filtering and recycling system.

[0054] It is conceivable that in some embodiments, the first filtering device 130 may be a dead-end filter. In view of the principle of dead-end filtering, the dead-end filter can be well adapted to such a small feed amount, so that the production capacity can be kept stable even when the feed amount is reduced.

[0055] Regarding the circulation loop 20, Figure 2As shown, it is conceivable that a heat exchanger 230 may also be connected to the circulation loop 20. The feed port and the discharge port of the heat exchanger 230 may be connected to the discharge port 212 and the feed port 211 of the reactor 210, respectively, so as to recover heat from the material to maintain the temperature of the reaction system. An ejector 240 may also be connected to the circulation loop 20. The ejector 240 may be connected to the feed port 211 of the reactor 210 upstream of the feed port 211 to atomize the material before it enters the reactor 210, thereby increasing the contact area between the components of the material.

[0056] It is conceivable that the outlet 122 of the first return line 120 can be connected to the circulation loop 20 upstream of the ejector 240, such as Figure 2 In this case, the first concentrated solution and the material in the circulation loop 20 can be mixed before entering the ejector 240, so that the two parts of the material can enter the reactor 210 after being fully mixed, which is conducive to uniform contact between the reaction components and improves the reaction efficiency.

[0057] In some embodiments, the second discharge port 134 of the first filtering device 130 may be configured to continuously discharge the first concentrated solution, so that the first concentrated solution continuously flows back to the circulation loop 20 .

[0058] Exemplarily, the filtration recovery system 10 may include a pump 101 disposed downstream of the second discharge port 134 to provide sufficient fluid pressure difference to drive the first concentrated solution to return to the circulation loop 20. Through the continuous operation of the pump 101, the first concentrated solution can be continuously returned to the circulation loop 20, thereby, on the one hand, realizing the continuous recycling of the catalyst, and on the other hand, preventing excessive catalyst solid particles from being enriched in the first filter device 130 (for example, enriched in its lower part), thereby preventing the filtering effect from being affected. In addition, in this way, for example, the flow of the concentrated solution at the lower part will not affect the filtering effect of the filter element above, thereby ensuring the stable output of the clear solution, without affecting the material circulation process, and truly achieving stable operation.

[0059] It is understandable that the pump 101 may be a pump of the same type as the pump 220 , for example, a centrifugal pump, a reciprocating pump, or other suitable types of pumps, which are not limited herein.

[0060] In some embodiments, Figure 3 and Figure 4 As shown, the first filter device 130 may further include a first liquid stabilizing device 135. The first liquid stabilizing device 135 may be arranged upstream of the first filter element 131 to reduce the turbulence of the material to be introduced into the first filter element 131.

[0061] Specifically, the material circulates at a high speed in the circulation loop 20, so the material diverted through the first diversion pipeline 110 enters the first filter device 130 at a faster flow rate and in a substantially turbulent state. In the case where the first liquid stabilizing device 135 is located upstream of the first filter element 131, the material flowing to the first filter element 131 will first pass through the first liquid stabilizing device 135, and then flow to the first filter element 131 with a reduced turbulence degree or turbulence intensity, for example, in a substantially flat flow state.

[0062] By allowing the material to flow through the first filter element 131 in a relatively stable state, vibration or impact on the first filter element 131 caused by material turbulence can be avoided, which helps to ensure a smooth filtration process, thereby improving filtration efficiency and extending the service life of the first filter element 131.

[0063] On the other hand, other materials that do not flow toward the downstream of the first filter element 131, that is, the first concentrated solution that flows toward the second discharge port 134, do not need to first pass through the first liquid stabilizing device 135, and thus can be kept in a substantially turbulent state, which helps to prevent the catalyst in the materials from settling and staying in the first filter device 130. This helps to return all or substantially all of the catalyst to the circulation loop, improves the efficiency of catalyst recovery and reuse, and reduces or avoids the clogging of the first filter device 130.

[0064] In addition, the first liquid stabilizing device 135 can be configured to intercept the catalyst within a specific particle size range in the material, for example, intercept the catalyst with a larger particle size, so that it can be directly returned to the circulation loop 20 without passing through the first filter element 131. In this way, the processing flux of the filter element is further reduced to a certain extent, thereby further reducing the difficulty of material separation and reducing the risk of clogging of the first filter device.

[0065] It is conceivable that the first liquid stabilizing device 135 may be made of a metal material with a certain strength, so that the first liquid stabilizing device 135 has higher wear resistance and impact resistance, thereby improving its stability and durability.

[0066] In some embodiments, reference Figure 3 , Figure 4 , Figure 5 and Figure 6 The first liquid stabilizing device 135 may include a plurality of flow channel holes 136, and the plurality of flow channel holes 136 are arranged so that the material passing through the first liquid stabilizing device 135 flows to the first filter element 131 in the same flow direction, so as to further improve the smoothness of the material flow.

[0067] For example, Figure 5 and Figure 6As shown, the first liquid stabilizing device 135 may have a grid structure, and the plurality of flow channel holes 136 are a plurality of mesh holes in the grid structure. However, the structure of the first liquid stabilizing device 135 and the form of the flow channel holes 136 are not limited thereto.

[0068] Exemplarily, for example, for the first filter device 130 of dead-end filtering type, the multiple flow channel holes 136 can have axes parallel to each other, which can be perpendicular or approximately perpendicular to the filtering surface of the first filter element 131 used for filtering, such as a filter membrane, so that materials that originally flow in different directions tend to flow vertically toward the filtering surface as a whole after passing through the flow channel holes 136, thereby further improving the filtering efficiency.

[0069] It is conceivable that the size of the multiple flow holes 136 can also be designed according to the size of the catalyst particles in the material, and designed so that the multiple flow holes 136 can intercept the catalyst within a specific particle size range in the material to provide a certain pre-filtration effect.

[0070] In some embodiments, each of the plurality of flow channel holes 136 may have a smooth inner surface to prevent the solid or liquid components in the material from adhering to and depositing on the inner surface, thereby reducing the risk of clogging of the first liquid stabilizing device 135 and extending the service life. For example, the smooth inner surface may be achieved by physical, chemical or electrochemical means, such as mechanical polishing or surface coating, spraying, etc.

[0071] In some embodiments, Figure 6 , Figure 8 , Fig.10 As shown, the first liquid stabilizing device 135 may further include a central hole 137 , the size of which may be larger than the size of the flow channel hole 136 , thereby allowing a relatively large flow of material to pass through the central hole 137 , which helps to improve the liquid stabilizing efficiency and the filtering efficiency.

[0072] It is understandable that the first liquid stabilizing device 135 can be adapted to the configuration of the first filtering device 130. For example, corresponding to the first filtering device 130 having a circular body, the first liquid stabilizing device 135 can be as follows when viewed from above: Figure 5 , Figure 7 and Fig. 9 As shown in the circular shape or as Figure 6 , Figure 8 and Fig.10 It is shown in a ring shape.

[0073] Reference Figure 6It can be imagined that the ratio R / r of the outer radius R of the annular shape of the first liquid stabilizing device 135 when viewed from above to its inner radius r can be between 2 and 10, for example, between 3 and 5, wherein the inner radius r is the radius of the center hole 137. If R / r is greater than 10, the center hole 137 is relatively too small, resulting in too fast a change in the flow velocity of the material when passing through the center hole 137, and poor flow stability. If R / r is less than 2, the center hole 137 is relatively too large, resulting in most of the material passing directly through the center hole 137, and thus the liquid stabilizing and catalyst pre-interception effects cannot be effectively achieved.

[0074] It is conceivable that the first liquid stabilizing device 135 may be in the shape of a flat plate, such as Figure 5 and Figure 6 shown.

[0075] It is conceivable that the first liquid stabilizing device 135 may be in a conical shape, such as Figure 7 and Figure 8 For example, in Figure 7 In the case of , the cone angle α of the cone shape may be in the range between 90° and 180°.

[0076] It is conceivable that the first liquid stabilizing device 135 may be in an arc shape, such as Fig. 9 and Fig.10 In the case where the first liquid stabilizing device 135 does not include a central hole, refer to Fig. 9 The ratio R1 / H of the radius R1 of the circular shape of the first stabilizing liquid device 135 when viewed from above to the first height H of the first stabilizing liquid device 135 may be between 1.2 and 10, for example, between 3 and 6, wherein the first height H is the vertical distance from the highest point to the lowest point of the circular arc shape of the first stabilizing liquid device 135. In the case where the first stabilizing liquid device 135 includes a central hole 137, as shown in FIG. Fig.10 As shown, the ratio R2 / h of the outer radius R2 of the annular shape of the first liquid stabilizing device 135 when viewed from above to the second height h can be between 1.5 and 10, for example, between 3 and 6, wherein the second height h is the vertical distance from the highest point of the arc shape of the first liquid stabilizing device 135, i.e., the center hole, to the lowest point of the arc shape. It can be understood that the radius R1 of the circular shape and the outer radius R2 of the annular shape mentioned above are both half of the chord length of the arc shape.

[0077] It can be understood that, in the case of a conical shape or an arc shape, the first liquid stabilizing device 135 can be configured to protrude toward the first filter element 131 so as to provide a guiding effect on the material, thereby helping to control the flow direction of the material.

[0078] In some embodiments, the amount of material diverted from the first diverting pipeline 110 can be configured to account for 0.1% to 20% of the amount of material in the circulation loop 20, for example, 0.5% to 10%. If the proportion is less than 0.1%, the amount of diverted material is too small, which may not guarantee the amount of clear liquid and normal production needs on the one hand, and may not ensure that the first concentrated liquid in the first filter device 130 has the desired turbulent state on the other hand. On the contrary, if the proportion exceeds 20%, the amount of diverted material is too much, which may increase the demand for the equipment volume of the first filter device 130 and increase the production cost on the other hand, and the flushing force on the first filter device 130 is too large due to the excessive flow rate of the material, shortening the service life of the device.

[0079] In addition, the amount of the first concentrated solution refluxed from the first reflux pipeline 120 can be configured to account for 3% to 50% of the amount of the material diverted from the first diversion pipeline 110, for example, 10% to 30%. If the proportion exceeds 50%, the amount of clear liquid actually filtered by the first filter element 131 may be too small, which is not conducive to maintaining production. If the proportion is less than 3%, the discharge amount of the first concentrated solution is too low, which easily causes the material to be deposited inside the first filter device 130 or in the pipeline, affecting the recycling of the catalyst.

[0080] It can be understood that the above proportions can be configured or adjusted by means of corresponding valves V1, V2, V3, etc.

[0081] In some embodiments, Figure 1 As shown, the filtration recovery system 10 may further include a clear liquid tank 102, and the first outlet 133 of the first filtration device 130 is connected to the feed port of the clear liquid tank 102 so that the first clear liquid enters the clear liquid tank 102. Exemplarily, the first clear liquid may be controlled by valves V4, V5, and V6. For example, after the process system is stable, the valve V4 may be opened to transport the clear liquid in the clear liquid tank 102 to the downstream so that the clear liquid can be subsequently processed or utilized.

[0082] High-speed circulation of materials can easily cause catalyst pulverization, which may lead to a decrease in catalyst activity or even deactivation. In this regard, in some embodiments, such as Figure 2As shown, the filtering and recycling system 10 may further include a second filtering device 140, which includes a second filtering element 141, a second feed port 142, a third discharge port 143, and a fourth discharge port 144. The second feed port 142 of the second filtering device 140 is connected to the first discharge port 133 of the first filtering device 130, so that the first clear liquid enters the second filtering device 140. The second filtering element 141 is used to filter the first clear liquid entering the second filtering device 140 to form a second clear liquid and a second concentrated liquid. The third discharge port 143 is used to discharge the second clear liquid, and the fourth discharge port 144 is used to discharge the second concentrated liquid.

[0083] The filtering accuracy of the second filtering device 140 is higher than that of the first filtering device 130, so it can specifically screen and filter out those catalysts with smaller particle sizes, lower activity or even deactivated, and retain those catalysts with larger particle sizes and higher activity, thereby effectively reducing the unnecessary loss of high-efficiency catalysts. In this case, when new catalysts need to be added, the above design allows for effective supplementation of catalysts with a relatively small amount of addition, reducing the amount of catalyst used and improving the economic benefits of the system.

[0084] It is conceivable that the first filter device 130 and the second filter device 140 can use membrane filtration, and the material of the membrane can be one or a combination of ceramic, mogan stone, stainless steel, alloy. In addition, similar to the first filter device 130, the second filter device 140 can include a second liquid stabilizing device 145.

[0085] It is also conceivable that the filtration recovery system 10 may be provided with more filtration devices in a similar manner to achieve a more refined catalyst separation effect through multi-stage filtration.

[0086] In some embodiments, Figure 2 As shown, the filtering and recycling system 10 may further include a clear liquid tank 103, and the third outlet 143 of the second filtering device 140 is connected to the feed port of the clear liquid tank 103, so that the second clear liquid enters the clear liquid tank 103. Exemplarily, the second clear liquid may be controlled by valves V100, V110, V130, etc. For example, after the process system is stable, the valve V130 may be opened to transport the clear liquid in the clear liquid tank 103 to the downstream.

[0087] In some embodiments, Figure 2 As shown, the filtration recovery system 10 may further include a catalyst recovery tank 104, and the fourth outlet 144 is connected to the catalyst recovery tank 104 so that the second concentrated liquid enters the catalyst recovery tank 104. A valve V140 may be provided upstream of the catalyst recovery tank 104 to control the entry of materials.

[0088] In some embodiments, Figure 2 As shown, the filtration recovery system 10 can also include a second diversion pipeline 150 and a second return pipeline 160, the inlet 151 of the second diversion pipeline 150 is connected to the circulation loop 20 and the outlet 152 is connected to the second feed port 142 of the second filter device 140, and the inlet 161 of the second return pipeline 160 is connected to the fourth discharge port 144 and the outlet 162 is connected to the circulation loop 20.

[0089] In this case, the first filter device 130 and the second filter device 140 can be allowed to independently undertake the filtering task of the entire system. Figure 2 When valves V10, V20, V40, V60, and V70 are open and other valves are closed, the first filter device 130 can independently undertake the filtering task. When valves V50, V30, V80, V90, and V110 are open and other valves are closed, the second filter device 140 can independently undertake the filtering task.

[0090] In this way, when one of them needs to perform maintenance operations such as cleaning, repair or replacement of filter elements, the other can take charge of the filtering task, thereby maintaining the continuous operation of the filtering and recycling system.

[0091] In some embodiments, Figure 3 As shown, the filtration recovery system 10 may further include a control device 170 and a cleaning device 180, which are connected to each other in a communication manner, and the control device 170 is configured to control the cleaning device 180 to automatically clean the first filter element 131 according to the pressure difference between the upstream and downstream of the first filter element 131. The control device 170 is, for example, a central controller.

[0092] For example, Figure 3 and Figure 4 As shown, the filtering recovery system 10 may further include a pressure difference detection device 105, which is used to detect the pressure difference between the upstream and downstream of the first filter element 131. The pressure difference detection device 105 may be connected to the control device 170 for communication with each other.

[0093] It is conceivable that Figure 3 As shown, the pressure difference detection device 105 can be arranged in conjunction with the valve V1 on the first branch pipeline 110. When the pressure difference of the first filter element 131 is detected to increase, the valve opening of the first branch pipeline 110 will be increased accordingly, thereby ensuring the stability of the clear liquid discharge amount.

[0094] It is conceivable that the filtration recovery system 10 may further include another pressure difference detection device 106, which is used to detect the pressure difference between the upstream and downstream of the second filter element 141, and which may be arranged in conjunction with the valve V30 on the second diversion pipeline 150, such as Figure 4 shown.

[0095] In some embodiments, the cleaning device 180 can be configured to perform at least one of backwashing and power wave cleaning. Exemplarily, the cleaning device 180 can be configured to backwash the first filter element 131 with the clean liquid in the clean liquid tank 102 to avoid introducing other contamination into the filtration recovery system.

[0096] In the case of using power wave cleaning, the cleaning device may include a vibration plate for generating power waves, so that the catalyst particles attached to the first filter element fall off under the action of the power waves. In this case, there is no need to empty and dismantle the filter device, and the cleaning operation is more efficient and convenient.

[0097] It is conceivable that the power wave can be a high frequency power wave. For example, the power wave can be an ultrasonic wave with a frequency between 20kHz and 1000kHz and a power between 50kW and 1000kW.

[0098] In the case of combining backwashing and power wave cleaning, for example, backwashing can be performed first and then power wave cleaning, or power wave cleaning can be performed first and then backwashing. In this case, the automatic cleaning time can be further shortened and the cleaning effect can be improved.

[0099] In some embodiments, the material can be a material for preparing methylaniline, diaminotoluene or o-chloroaniline by catalytic hydrogenation. In this case, the filtration recovery system 10 can be used together with a process system for synthesizing methylaniline by hydrogenation of nitrotoluene, a process system for synthesizing diaminotoluene by hydrogenation of dinitrotoluene, or a process system for synthesizing o-chloroaniline by hydrogenation of o-nitrochlorobenzene, but is not limited thereto. It should be understood that the filtration recovery system 10 can also be used together with other process systems for continuous catalytic hydrogenation reactions involving high-speed circulation of materials similar to the above examples.

[0100] According to an embodiment of the present disclosure, a process system for continuous catalytic hydrogenation reaction is also provided, which includes: a reactor 210, wherein the reactor 210 is used to perform a catalytic hydrogenation reaction therein; and a filtration recovery system 10 according to an embodiment of the present disclosure. The feed port 211 and the discharge port 212 of the reactor 210 are connected to form a circulation loop 20 for circulating the material therein. The first branch line 110 and the first reflux line 120 of the filtration recovery system 10 are connected to the circulation loop 20.

[0101] The above-mentioned process system for continuous catalytic hydrogenation reaction can be used for hydrogenation of nitrotoluene to synthesize methylaniline, hydrogenation of dinitrotoluene to synthesize diaminotoluene or hydrogenation of o-nitrochlorobenzene to synthesize o-chloroaniline or similar catalytic hydrogenation reactions, but is not limited thereto.

[0102] Although the present disclosure has been described with reference to exemplary embodiments, it should be understood that the present disclosure is not limited to the specific embodiments described and shown in detail herein. Various changes may be made to the exemplary embodiments by those skilled in the art without departing from the scope defined by the claims of the present disclosure.

[0103] The features mentioned and / or shown in the above description of the exemplary embodiments of the present disclosure may be combined in the same or similar manner into one or more other embodiments, combined with features in other embodiments or substituted for corresponding features in other embodiments. The technical solutions obtained by these combinations or substitutions shall also be deemed to be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.

Claims

1. A filtering and recycling system, characterized in that: include: A first branch pipeline, the inlet of which is connected to a circulation loop, wherein the circulation loop is a loop formed by connecting a feed inlet and a discharge outlet of a reactor for performing a catalytic hydrogenation reaction; A first reflux pipeline, an outlet of which is connected to the circulation loop; and The first filter device comprises a first filter element, a first feed port, a first discharge port and a second discharge port, the outlet of the first branch pipeline is connected to the first feed port, and the inlet of the first reflux pipeline is connected to the second discharge port, the first filter element is used to filter the material entering the first filter device to form a first clear liquid and a first concentrated liquid, the first discharge port is used to discharge the first clear liquid, and the second discharge port is used to discharge the first concentrated liquid, wherein the second discharge port is located below the first feed port, The first filtering device further comprises a first liquid stabilizing device for reducing the turbulence of the material passing therethrough, wherein the first liquid stabilizing device is arranged below the first filtering element and above the first feed inlet. The second discharge port is configured to continuously discharge the first concentrated solution so that the first concentrated solution continuously flows back to the circulation loop. The first liquid stabilizing device comprises a plurality of flow channel holes, and the plurality of flow channel holes are arranged so that the material passing through the first liquid stabilizing device flows to the first filter element in the same flow direction. Each of the plurality of flow channel holes has a smooth inner surface, The first liquid stabilizing device is in a flat plate shape, a conical shape or an arc shape, and includes a central hole, the size of the central hole is larger than the size of the flow channel hole, The filtration recovery system also includes a control device and a cleaning device, wherein the control device and the cleaning device are communicatively connected, and the control device is configured to control the cleaning device to automatically clean the first filter element according to the pressure difference between the upstream and downstream of the first filter element.

2. The filtration recovery system according to claim 1, characterized in that: The amount of material diverted from the first diversion line is configured to account for 0.1% to 20% of the amount of material in the circulation loop, and the amount of the first concentrate refluxed from the first reflux line is configured to account for 3% to 50% of the amount of material diverted from the first diversion line.

3. The filtration recovery system according to claim 1, characterized in that: It also includes a second filtering device, which includes a second filtering element, a second feed port, a third discharge port and a fourth discharge port. The filtering accuracy of the second filtering device is higher than that of the first filtering device. The second feed port is connected to the first discharge port. The second filtering element is used to filter the first clear liquid entering the second filtering device to form a second clear liquid and a second concentrated liquid. The third discharge port is used to discharge the second clear liquid, and the fourth discharge port is used to discharge the second concentrated liquid.

4. The filtration recovery system according to claim 3, characterized in that: A catalyst recovery tank is also included, and the fourth discharge port is connected to the catalyst recovery tank.

5. The filtration recovery system according to claim 3 or 4, characterized in that: It also includes a second shunt pipeline and a second reflux pipeline, the inlet of the second shunt pipeline is connected to the circulation loop and the outlet is connected to the second feed port of the second filtering device, and the inlet of the second reflux pipeline is connected to the fourth discharge port and the outlet is connected to the circulation loop.

6. The filtration recovery system according to claim 1, characterized in that: The cleaning device is configured to perform at least one of backwash cleaning and power wave cleaning.

7. The filtration recovery system according to claim 1, characterized in that: The material is a material used for preparing methylaniline, diaminotoluene or o-chloroaniline through catalytic hydrogenation reaction.

8. A process system for continuous catalytic hydrogenation reaction, characterized in that: include: A reactor for carrying out a catalytic hydrogenation reaction therein; as well as According to any one of claims 1 to 7, the first branch line and the first reflux line of the filtration recovery system are connected to a circulation loop formed by connecting a feed port and a discharge port of the reactor.

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