Energy-saving synthesis device of molecular sieve

Abstract

The utility model provides an energy-saving synthesis device of a molecular sieve, aiming at solving the problem that a large amount of heat is lost before and after crystallization synthesis. The crystallization system comprises a crystallization device (2) and is characterized in that a material output end (23) of the crystallization device (2) is connected with a first inlet of a heat exchanger (3), a second inlet of the heat exchanger (3) is used as a raw material inlet, a second outlet of the heat exchanger (3) is connected with a material input end (221) of the crystallization device (2), the first inlet is communicated with the first outlet through a pipeline, and the second inlet is communicated with the second outlet through a pipeline. And the second inlet is communicated with the second outlet through a pipeline. Materials of the crystallization kettle are subjected to crystallization reaction at high temperature, cold materials entering the crystallization kettle and hot materials exiting from the crystallization kettle are subjected to cold-heat exchange through the heat exchanger, almost all energy of the hot materials can be transferred to the cold materials, and the crystallization synthesis energy consumption is greatly reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of molecular sieve synthesis, in particular to an energy-saving synthesis device of a molecular sieve. Background Art

[0002] At present, the synthesis of ZSM-5 molecular sieve mainly uses silica sol, water glass, ethyl orthosilicate, aluminum sulfate, sodium aluminate, organic amines and other chemical products as raw materials. A single synthesis reactor is used to add all the materials. After the reactor is closed, it is heated to a certain temperature (usually 180℃) with a heat source. The temperature is fixed for a certain time (usually 24 hours). Then the heat source is turned off and the cooling source is turned on to cool it down. After that, the crystallized synthetic slurry is filtered, exchanged, washed with water, and dried to obtain qualified ZSM-5 molecular sieve. The ZSM-5 molecular sieve is crystallized and synthesized by frequent intermittent heating and cooling in a single reactor. A large amount of heat is lost before and after the crystallization synthesis, resulting in a high cost for the synthesis of ZSM-5 molecular sieve.

[0003] Patent application CN 117380127 A discloses a molecular sieve continuous crystallization system and method, which arranges multiple crystallization kettles in series from top to bottom, with the upstream crystallization kettle connected to the pulping tank and the downstream crystallization kettle connected to the flash tank. This reduces the problem of uneven material residence time and improves product quality, crystallinity, and silicon-aluminum ratio compared to intermittent crystallization processes. The high head difference between the multiple crystallization kettles allows the material to be transported by gravity, eliminating the need for a transfer pump between the multiple crystallization kettles, saving power costs. However, the following problems still exist:

[0004] 1. The crystallization kettle temperature is 170-200°C. After entering the flash tank, the material temperature drops to 100-150°C, preferably 120°C. The slurry material after flash evaporation is transported downstream via a slurry delivery pump. This patent does not address the problem of large heat loss before and after crystallization synthesis.

[0005] 2. The crystallization kettle's material input is located at the bottom, and the material output is at the bottom. The stirring mechanism within the crystallization kettle uses multi-layer propellers or pitched-blade turbine-style impellers. After entering each crystallization kettle, the material is stirred upward along the inner wall of the kettle by the stirring mechanism and returns to the bottom of each crystallization kettle through the center at the liquid level. Because the material input and output are close together, the material may be directly discharged, making it difficult to ensure that the material moves along the predetermined route and remains in the kettle for a sufficient time before being discharged. Utility Model Content

[0006] In order to solve the problems in the background technology, the utility model provides an energy-saving synthesis device for molecular sieves to solve the problem of large-scale heat loss before and after crystallization synthesis.

[0007] The technical solution of this utility model is:

[0008] An energy-saving synthesis device for molecular sieves includes a crystallization device 2, characterized in that: the material output end 23 of the crystallization device is connected to the first inlet of the heat exchanger 3, the second inlet of the heat exchanger 3 serves as the raw material inlet, the second outlet of the heat exchanger 3 is connected to the material input end 221 of the crystallization device 2, the first inlet and the first outlet are connected by a pipeline, and the second inlet and the second outlet are connected by a pipeline.

[0009] Preferably, the second inlet of the heat exchanger 3 is connected to the raw material premixing tank 1 .

[0010] Preferably, the crystallization device includes at least one crystallization kettle. When there are two or more crystallization kettles, the multiple crystallization kettles are connected in series.

[0011] Preferably, when there are two crystallization reactors, the material output end 23 of the first crystallization reactor is higher than the material input end 221 of the second crystallization reactor. When there are three crystallization reactors, the material output end 23 of the first crystallization reactor is higher than the material input end 221 of the second crystallization reactor, and the material output end 23 of the second crystallization reactor is higher than the material input end 221 of the third crystallization reactor, and so on. More preferably, the last crystallization reactor has an upper side feed and a bottom discharge to ensure that no gas phase is included in the process.

[0012] Preferably, the material output end 23 of the crystallization kettle is located at a set liquid level height position in the crystallization kettle.

[0013] Preferably, the last crystallization kettle feeds from the upper side and discharges from the bottom; the material input end 221 of each of the remaining crystallization kettles is close to the top of the kettle body 21 of the crystallization kettle, and the material input end 221 of the crystallization kettle is connected to the material conduit 222, the material conduit 222 is located in the kettle body 21 of the crystallization kettle and the outlet of the material conduit 222 is located at the bottom of the kettle body 21; or the material input end 221 of each of the remaining crystallization kettles is located at the bottom of the kettle body 21.

[0014] Preferably, the bottom of the material conduit 22 is fixed to the inside of the kettle body 21 through a material conduit bracket 223 .

[0015] Preferably, at least one set of external heat-conducting components is provided outside the kettle body 21, and the external heat-conducting components include a spiral half-tube inlet 261, a spiral half-tube 262 and a spiral half-tube outlet 263 connected in sequence, and each set of external heat-conducting components is connected in parallel.

[0016] Preferably, the cross section of the spiral half tube 262 is semicircular, and the arc surface where the diameter of the semicircle is located faces the outer surface of the kettle body 21.

[0017] Preferably, the kettle body 21 is provided with an internal heat-conducting component, which includes an internal heat-conducting medium inlet 241 , a spiral coil 244 and an internal heat-conducting medium outlet 246 that are connected in sequence, and the spiral coil 244 is located inside the kettle body 21 .

[0018] Preferably, the internal heat-conducting medium inlet 241 is connected to three inlet branch pipes 243 through a first four-way pipe 242, and the three inlet branch pipes are respectively connected to three outlet branch pipes 245 through three spiral coils 244, and the three outlet branch pipes 245 are connected to the internal heat-conducting medium outlet 246 through a second four-way pipe 247; the three spiral coils 244 are arranged in sequence from top to bottom on the outer wall of the kettle body 21.

[0019] Preferably, a stirring shaft 27 is further provided inside the crystallization kettle. A bottom bearing bracket 252 is fixed to the bottom of the kettle body 21 , a bottom bearing 251 is fixed to the bottom bearing bracket 252 , and the bottom of the stirring shaft 27 is movably connected to the bottom bearing 251 .

[0020] Preferably, the heat exchanger is a wide-channel flat plate heat exchanger, which is not only less prone to clogging and scaling, but also has a heat exchange efficiency 2-6 times that of a tube-sheet heat exchanger.

[0021] The advantages of the present invention are as follows: (1) The material in the crystallization kettle of the present invention undergoes a crystallization reaction at high temperature, and the material output end of the crystallization kettle outputs a high-temperature synthetic slurry of about 170°C, which is input into the heat exchanger. At the same time, the raw materials at room temperature are mixed and enter the heat exchanger as a cold source. The high-temperature synthetic slurry and the room-temperature raw materials exchange heat through the heat exchanger 3, and the raw materials are heated and enter the crystallization kettle, which saves the heat energy consumption of the crystallization kettle and accelerates the cooling speed of the synthetic slurry, so that the synthetic slurry can be filtered, exchanged, washed, and other operations can be performed later. The heat loss before and after the entire crystallization is small, which saves heat energy loss and reduces the cost of molecular sieve synthesis.

[0022] (2) The material input end 221 is at the top, and the outlet of the material conduit 222 connected to the material input end 221 is located at the bottom of the crystallization kettle. The material falls to the bottom of the crystallization kettle by the gravity of the material itself, and the new material entering the crystallization kettle is located at the bottom of the crystallization kettle. With the addition of new material, the original material gradually moves upward, so that all the materials entering the crystallization kettle can maintain the moving trajectory from the bottom to the top, thereby ensuring the residence time of the material entering the kettle body, the material is heated evenly, and the material is evenly mixed and reacts fully, thereby improving the reaction efficiency.

[0023] (3) The external heat conduction components and the internal heat conduction components are connected in parallel in multiple groups, thereby reducing the temperature difference between the upper and lower parts of the kettle body. This is especially suitable for large-capacity kettle bodies. The temperature inside the kettle body is more uniform, which improves the heating efficiency and reaction efficiency.

[0024] (4) For large-capacity kettles, the bottom of the stirring shaft is connected to the inside of the kettle through a bottom bearing, which improves the balance and stability of the stirring shaft and is particularly suitable for large-capacity crystallization kettles. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0026] Figure 2 This is a schematic diagram of the structure of the crystallization kettle of the utility model.

[0027] Among them: 1-raw material premixing tank; 2-crystallization device; 21-kettle body; 221-material input end; 222-material conduit; 223-material conduit bracket; 23-material output end; 241-internal heat transfer medium inlet; 242-first four-way pipe; 243-inlet branch pipe; 244-spiral coil; 245-outlet branch pipe; 246-internal heat transfer medium outlet; 247-second four-way pipe; 251-bottom bearing; 252-bottom bearing bracket; 261-spiral half-pipe inlet; 262-spiral half-pipe; 263-spiral half-pipe outlet; 27-agitation shaft; 28-manhole; 29-bottom drain port; 3-heat exchanger. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention are described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0029] like Figure 1 As shown, the energy-saving synthesis device of molecular sieve includes a crystallization device 2, the material output end 23 of the crystallization device is connected to the first inlet of the heat exchanger 3, the second inlet of the heat exchanger 3 serves as the raw material inlet, and the second outlet of the heat exchanger 3 is connected to the material input end 221 of the crystallization device 2. The first inlet and the first outlet are connected by a pipeline, and the second inlet and the second outlet are connected by a pipeline.

[0030] This utility model utilizes a wide-channel flat-plate heat exchanger with smooth fluid channels on both the hot and cold sides. The heat exchanger design and calculations ensure that material flow rates (0.4-1.2 m / s) on both sides are maintained when channel widths are 8-150 mm. This reduces the likelihood of internal solids depositing and scaling, ensuring long-term, continuous, and stable operation. This heat exchanger is not only less susceptible to clogging and scaling, but also boasts a heat transfer efficiency 2-6 times higher than tube-sheet heat exchangers.

[0031] Preferably, the second inlet of the heat exchanger 3 is connected to the raw material premixing tank 1, and various raw materials can also be directly introduced into it.

[0032] Preferably, the crystallization device includes at least one crystallization kettle. When there are two or more crystallization kettles, the multiple crystallization kettles are connected in series.

[0033] Preferably, when there are two crystallization kettles, the material output end 23 of the first crystallization kettle is higher than the material input end 221 of the second crystallization kettle; when there are three crystallization kettles, the material output end 23 of the first crystallization kettle is higher than the material input end 221 of the second crystallization kettle, and the material output end 23 of the second crystallization kettle is higher than the material input end 221 of the third crystallization kettle; and so on.

[0034] Preferably, the last crystallization reactor is fed from the upper side and discharged from the bottom to ensure that no gas phase is contained in the process.

[0035] The material output end 23 of each of the remaining crystallization kettles is located at a set liquid level height position in the crystallization kettle, and the material input end 221 is close to the top of the kettle body 21 of the crystallization kettle. The material input end 221 of the crystallization kettle is connected to the material conduit 222, and the material conduit 222 is located in the kettle body 21 of the crystallization kettle and the outlet of the material conduit 222 is located at the bottom of the kettle body 21; the material conduit 222 transports the material to the bottom of the kettle body 21, ensuring that the new material always starts to move upward from the bottom of the kettle body 21 and eventually overflows from the material output end 23, ensuring that all materials have a uniform residence time in the kettle body 21 and a uniform heating time of the materials, thereby ensuring that the materials obtain uniform heat from the outside, react fully, and improve reaction efficiency.

[0036] Alternatively, the material output end 23 of each of the other crystallization kettles is located at a set liquid level height in the crystallization kettle, and the material input end 221 is located at the bottom of the kettle body 21 .

[0037] The two designs of the material input end of the crystallization kettle are essentially bottom feeding, that is, the previous crystallization kettles connected in series are bottom feeding and discharge from the upper side to form a pipeline flow.

[0038] 2-10 or more crystallization kettles with stirring devices are connected in series as a whole by means of differential power transmission or liquid mechanical equipment power transmission to ensure the crystallization residence time required for molecular sieve synthesis, realize the continuity of feeding and discharging of the crystallization kettle, and achieve continuous production of molecular sieve crystallization stage, which greatly improves the synthesis efficiency; the crystallization synthesis residence time can be flexibly adjusted by adjusting the flow rate of feeding and discharging or fixing the flow rate, or by increasing the size of a single kettle or by increasing the number of series kettles, which also allows for future industrial production with a larger multiple; the series connection can make the volume of a single kettle not too large, solving the problems of difficult installation and high investment cost of a large-volume single kettle; it avoids the problems of unstable synthetic products caused by frequent temperature increase and decrease in the intermittent synthesis process, and obtains qualified molecular sieves while keeping other subsequent slurry treatment processes unchanged.

[0039] like Figure 2As shown, the crystallization kettle includes a kettle body 21, which is provided with a material input end 221, a material output end 23, a stirring shaft 27, a manhole 28, a bottom drain port 29, an external heat conduction component, an internal heat conduction component, etc.

[0040] In order to prevent the material from generating thrust on the material conduit 222 under the action of the stirring shaft 27 and causing damage to the material conduit 222 , preferably, the bottom of the material conduit 222 is fixed to the inside of the kettle body 21 through a material conduit bracket 223 .

[0041] Preferably, at least one external heat-conducting assembly is disposed outside the kettle 21. The external heat-conducting assembly comprises a spiral half-tube inlet 261, a spiral half-tube 262, and a spiral half-tube outlet 263, which are interconnected in sequence. Hot steam is introduced into the external heat-conducting assembly. Providing multiple sets of external heat-conducting assemblies in parallel prevents the spiral half-tubes 262 from extending too long and causing unbalanced steam distribution. This reduces the temperature difference between the upper and lower portions of the kettle 21, making it particularly suitable for large-capacity kettles. The internal temperature of the kettle 21 is more uniform, thereby improving heating and reaction efficiency.

[0042] Further preferably, the cross section of the spiral half tube 262 is semicircular, and the arc surface where the diameter of the semicircle is located faces the outer surface of the kettle body 21. Compared with the spiral tube with a circular cross section, the semicircular spiral half tube has a larger contact area and higher heating efficiency.

[0043] Preferably, the kettle body 21 is provided with an internal heat-conducting component, which includes an internal heat-conducting medium inlet 241 , a spiral coil 244 and an internal heat-conducting medium outlet 246 that are connected in sequence, and the spiral coil 244 is located inside the kettle body 21 .

[0044] Further preferably, the internal heat transfer medium inlet 241 is connected to three inlet branch pipes 243 via a first cross-section pipe 242. The three inlet branch pipes are respectively connected to three outlet branch pipes 245 via three spiral coils 244. The three outlet branch pipes 245 are connected to the internal heat transfer medium outlet 246 via a second cross-section pipe 247. The three spiral coils 244 are arranged sequentially from top to bottom on the outer wall of the kettle body 21. The provision of multiple inlet branch pipes, outlet branch pipes, and spiral coils avoids a large temperature difference between the inlet and outlet of a whole spiral pipe, which would cause uneven heating of the material.

[0045] The crystallization kettle is also provided with a stirring shaft 27. For large-volume crystallization kettles, the stirring shaft is easily swung by the resistance of the material, thereby damaging the reducer. The present invention fixes a bottom bearing bracket 252 at the bottom of the kettle body 21, and fixes a bottom bearing 251 on the bottom bearing bracket 252. The bottom of the stirring shaft 27 is movably connected to the bottom bearing 251, thereby improving the balance and stability of the stirring shaft. The stirring shaft is preferably made of Stellite alloy, which is wear-resistant, acid-resistant, alkali-resistant, corrosion-resistant, and high-temperature-resistant.

[0046] The working process of this utility model is as follows:

[0047] (1) In the raw material premixing tank 1, the raw materials are mixed into a gel solution.

[0048] (2) A peristaltic pump is used to send the gel liquid into the heat exchanger. After the cold side (gel liquid) and the hot side material (hot material that has been crystallized and synthesized in the crystallization kettle) of the heat exchanger are exchanged at a stable flow rate, the cold material rises from 29.4℃ to 167.2℃, and the hot material that has been crystallized and synthesized drops from 170℃ to 32.2℃. After the temperature of the hot material drops, it enters the set receiving kettle with stirring.

[0049] (3) The cold material enters the crystallization kettle after heat exchange, and the crystallization reaction occurs at a constant temperature in the crystallization kettle.

[0050] (4) After the crystallization is completed, the hot material in the crystallization kettle is pressed into the hot side of the heat exchanger by the pressure in the kettle to realize heat exchange with the cold material in the heat exchanger.

[0051] The entire crystallization process is continuous and stable in this utility model. Each series-connected reactor is equipped with a heating source (serving as a constant-temperature heat source and a heating source for initial startup). After the last reactor discharges, a crystallization synthesis reactor heat exchanger is connected (one side of the heat exchanger carries the cold material entering the crystallization reactor, and the other side carries the hot material that has been synthesized). This crystallization synthesis heat exchanger achieves continuous heat transfer and recycling. The heat exchanger exchanges heat between the cold material entering the crystallization reactor and the hot material leaving the crystallization reactor, transferring nearly all of the hot material's energy to the cold material, significantly reducing the energy consumption of crystallization synthesis.

Claims

1. An energy-saving synthesis device for molecular sieves, comprising a crystallization device (2), characterized in that: The material output end (23) of the crystallization device (2) is connected to the first inlet of the heat exchanger (3), the second inlet of the heat exchanger (3) serves as a raw material inlet, the second outlet of the heat exchanger (3) is connected to the material input end (221) of the crystallization device (2), the first inlet and the first outlet are connected via a pipeline, and the second inlet and the second outlet are connected via a pipeline.

2. The energy-saving molecular sieve synthesis device according to claim 1, characterized in that: The second inlet of the heat exchanger (3) is connected to the raw material premixing tank (1).

3. The energy-saving molecular sieve synthesis device according to claim 1 or 2, characterized in that: The crystallization device (2) comprises at least one crystallization kettle. When there are two or more crystallization kettles, the multiple crystallization kettles are connected in series.

4. The energy-saving molecular sieve synthesis device according to claim 3, characterized in that: When there are two crystallization kettles, the material output end (23) of the first crystallization kettle is higher than the material input end (221) of the second crystallization kettle; when there are three crystallization kettles, the material output end (23) of the first crystallization kettle is higher than the material input end (221) of the second crystallization kettle, and the material output end (23) of the second crystallization kettle is higher than the material input end (221) of the third crystallization kettle; and so on.

5. The energy-saving molecular sieve synthesis device according to claim 4, characterized in that: The material output end (23) of the crystallization kettle is located at a set liquid level height position in the crystallization kettle.

6. The energy-saving molecular sieve synthesis device according to claim 5, characterized in that: The last crystallization kettle is fed from the upper side and discharged from the bottom; the material input end (221) of the remaining crystallization kettles is close to the top of the kettle body (21) of the crystallization kettle, the material input end (221) of the crystallization kettle is connected to the material conduit (222), the material conduit (222) is located in the kettle body (21) of the crystallization kettle and the outlet of the material conduit (222) is located at the bottom of the kettle body (21); or the material input end (221) of the remaining crystallization kettles is located at the bottom of the kettle body (21).

7. The energy-saving molecular sieve synthesis device according to claim 6, characterized in that: At least one group of external heat-conducting components is provided outside the body (21) of the crystallization kettle. The external heat-conducting components include a spiral half-tube inlet (261), a spiral half-tube (262) and a spiral half-tube outlet (263) that are connected in sequence, and each group of external heat-conducting components is connected in parallel.

8. The energy-saving molecular sieve synthesis device according to claim 7, characterized in that: The cross section of the spiral half tube (262) is semicircular, and the arc surface where the diameter of the semicircle is located faces the outer surface of the kettle body (21).

9. The energy-saving molecular sieve synthesis device according to claim 8, characterized in that: The kettle body (21) is provided with an internal heat-conducting component, which comprises an internal heat-conducting medium inlet (241), a spiral coil (244), and an internal heat-conducting medium outlet (246) that are connected in sequence, and the spiral coil (244) is located inside the kettle body (21).

10. The energy-saving molecular sieve synthesis device according to claim 9, characterized in that: The internal heat-conducting medium inlet (241) is connected to three inlet branch pipes (243) via a first four-way pipe (242); the three inlet branch pipes are respectively connected to three outlet branch pipes (245) via three spiral coils (244); the three outlet branch pipes (245) are connected to the internal heat-conducting medium outlet (246) via a second four-way pipe (247); the three spiral coils (244) are arranged in sequence from top to bottom on the outer wall of the kettle body (21).

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