Desublimation crystallization device for separating nitrile compounds

Abstract

The utility model relates to a desublimation crystallization device for separating nitrile compounds. The desublimation crystallization device mainly comprises a crystallization box and an internal component, the crystallization box is composed of a horizontally-placed conical cooling section and a box body crystallization section, the conical cooling section is in a quadrangular pyramid shape, the box body crystallization section is in a rectangular shape, a material inlet is formed in the conical opening position of the conical cooling section and used for inputting nitrile-containing gas phase products, a cooling N2 inlet is formed in the conical surface of the conical cooling section, and a cooling N2 outlet is formed in the conical surface of the box body crystallization section. The box body crystallization section is used for inputting chilling N2, a material outlet is formed in the bottom wall surface of the tail end of the box body crystallization section and used for outputting materials, and a gas outlet is formed in the wall surface of the tail end of the box body crystallization section and used for outputting residual gas after crystallization separation; and the inner component comprises a crystallization unit and a support frame. The desublimation crystallization box is simple in structure, convenient to operate and flexible and adjustable in process parameters, so that proper supersaturation degree, crystallization temperature and the like are convenient to control, precipitation of nitrile compounds is optimized, and the desublimation crystallization box is convenient to discharge, simple to maintain and capable of stably running for a long time.

Description

Technical Field

[0001] The utility model relates to a desublimation crystallization box, belonging to the technical field of separation of fine chemical products, in particular to separation of organic nitrile substances with desublimation and sublimation characteristics. Background Art

[0002] Nitrile compounds are a class of organic compounds containing cyano (-CN) and are important intermediates in organic synthesis. As important chemical raw materials, organic nitrile compounds are widely used in the manufacture of drugs, synthetic fibers and plastics, and are also used in electroplating, steel quenching and mineral processing industries. There are many methods for the synthesis of nitrile, mainly including the preparation of nitrile by HCN addition method; the preparation of nitrile by cyanation of halogenated hydrocarbons; the synthesis of nitrile by ammoxidation method; the preparation of nitrile by Sandmeyer reaction of diazonium salts; the preparation of nitrile by dehydration of amides, thioamides, ammonium acids or amination and dehydration of carboxylic acids and carboxylic acid esters. The reaction temperature of the dehydration or ammonia dehydration catalytic synthesis of nitrile is relatively high, and the product nitrile, unreacted raw materials and by-products are all output from the reactor in gaseous form. If a solvent is introduced into the reaction, the gaseous product will dissolve in the solvent to form a solution after cooling; if it is a solvent-free reaction, due to the sublimation characteristics of nitrile compounds, it is often necessary to use a sublimation crystallizer to collect the gaseous product and separate and purify the nitrile compounds therein.

[0003] The desublimation crystallizer commonly used in chemical production is mainly a cylindrical tank structure with a built-in fixed cooling tube. When the crystallizer is collecting, the gas phase material condenses into solids on the surface of the cooling tube and accumulates continuously. However, with the gradual increase of condensed materials, the heat transfer coefficient of the cooling tube decreases, the condensation effect becomes worse, and the product is taken out with the non-condensable gas more and more seriously. Patents such as CN206910841U, CN215195493U, and CN112439222A describe a continuous crystallization device, that is, the generated crystals are scraped off in time and separated from the system by devices such as scrapers or stirring paddles, thereby ensuring a good heat transfer rate, and the crystallization operation can be repeated to achieve the effect of continuous crystallization. However, these power devices often cause the internal structure of the crystallizer to be more complicated, and the operation and maintenance are more cumbersome. The long-term use of scrapers or stirring paddles causes serious wear of the equipment, and the falling metal debris will cause the product purity to decrease. Another common problem is scaling at the edges and corners. Once scaling occurs, the scale layer will continue to grow, which will have an adverse effect on stirring, mixing, heat and mass transfer in the crystallizer, seriously affecting the continuous and stable operation of the device, and requires regular shutdown and cleaning. Utility Model Content

[0004] In view of the problems existing in the prior art, the utility model provides a desublimation crystallization device and method with simple structure, easy operation and high heat exchange efficiency, which is used in the process of solvent-free high-temperature synthesis of nitrile to directly crystallize and separate nitrile compounds from gas phase products.

[0005] The technical solution of the utility model is as follows:

[0006] A desublimation crystallization device for separating nitrile compounds, the structure of which mainly includes: a crystallization box and internal components;

[0007] The crystallization box is composed of a horizontally placed conical cooling section and a box crystallization section, the conical cooling section is in a quadrangular pyramid shape, the box crystallization section is in a rectangular shape, a material inlet is provided at the conical mouth of the conical cooling section for inputting nitrile-containing gas phase products, a cooling N2 inlet is provided on the conical surface of the conical cooling section for inputting quenching N2, a material outlet is provided on the bottom wall surface of the end of the box crystallization section for outputting materials, and a gas outlet is provided on the end wall surface of the box crystallization section for outputting residual gas after crystallization separation;

[0008] The internal components include a crystallization unit and a support frame.

[0009] Preferably, two or more support frames are provided; and one or more crystallization units are provided, and the crystallization units are arranged between the support frames.

[0010] Preferably, the cross section of the crystallization unit is in a comb shape, a group of fins are vertically arranged on the metal bottom plate, and the fins are parallel to each other; the crystallization unit is supported on the support frame.

[0011] Preferably, cooling N2 inlets are provided on 1 to 4 conical surfaces of the conical cooling section, which are symmetrically distributed and used for inputting quenching N2.

[0012] Preferably, the angle between the conical surface of the conical cooling section and the central axis is 30-75°, more preferably 40-60°, so as to facilitate the rapid reduction of gas velocity after quenching.

[0013] Preferably, the gap between the fins of the crystallization unit is 3 to 30 mm.

[0014] Preferably, a guide rail is provided on the support frame to facilitate the positioning of the crystallization unit.

[0015] Preferably, the box crystallization section may be provided with a thermometer interface, a pressure gauge interface, and a safety discharge interface for monitoring the collection status of the material.

[0016] Preferably, a mirror observation port may be provided on the box crystallization section for real-time monitoring of the crystallization condition on the fins.

[0017] Beneficial Effects

[0018] Compared with the prior art, the crystallization device designed in the utility model has a simple structure, convenient operation, and flexible and adjustable process parameters such as feeding temperature and rate, cooling N2 temperature and flow rate, so as to facilitate the control of appropriate supersaturation, crystallization temperature, etc., optimize the precipitation of nitrile compounds, and convenient discharging and simple maintenance. Multiple crystallization devices can be used in parallel to realize continuous operation of reaction and separation integration, ensuring the long-term stable operation of the entire nitrile synthesis system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In the drawings that are not necessarily drawn to scale, the same reference numerals may describe similar parts in different views. The same reference numerals with letter suffixes or different letter suffixes may represent different instances of similar parts. The accompanying drawings generally illustrate various embodiments by way of example and not limitation, and together with the specification and claims, are used to illustrate the embodiments of the utility model. When appropriate, the same reference numerals are used in all drawings to refer to the same or similar parts. Such embodiments are illustrative and are not intended to be exhaustive or exclusive embodiments of the present device or method.

[0020] Figure 1 The figure is a schematic diagram of the appearance structure of a crystallization device for separating nitrile compounds according to the utility model.

[0021] Figure 2 The figure is a schematic diagram of the internal structure of a crystallization device for separating nitrile compounds according to the utility model.

[0022] Figure 3 The utility model is a schematic diagram of the crystallization unit structure of a crystallization device for separating nitrile compounds.

[0023] Reference numerals:

[0024] Crystallization box: 1- material inlet, 2- cooling N2 inlet; 3- cone cooling section, 4- box crystallization section, 5- material outlet, 6- gas outlet; internal components: 7- metal bottom plate, 8- support frame, 9- fins. DETAILED DESCRIPTION

[0025] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings, but are not intended to limit the present invention.

[0026] It should be understood that various modifications may be made to the embodiments disclosed herein. Therefore, the following description should not be considered as limiting, but merely as an example of an embodiment. Other modifications within the scope and spirit of the present disclosure will occur to those skilled in the art.

[0027] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the general description of the present disclosure given above and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure.

[0028] These and other characteristics of the invention will become apparent from the following description of a preferred form of embodiment given as a non-limiting example, with reference to the accompanying drawings.

[0029] It should also be understood that although the present invention has been described with reference to some specific examples, those skilled in the art will be able to realize many other equivalent forms of the present invention that have the features described in the claims and are therefore within the scope of protection defined thereby.

[0030] The above and other aspects, features and advantages of the present disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

[0031] Specific embodiments of the present disclosure are described hereinafter with reference to the accompanying drawings; however, it should be understood that the disclosed embodiments are merely examples of the present disclosure, which may be implemented in a variety of ways. Well-known and / or repeated functions and structures are not described in detail to avoid obscuring the present disclosure with unnecessary or redundant details. Therefore, the specific structural and functional details disclosed herein are not intended to be limiting, but merely serve as a basis and representative basis for the claims to teach those skilled in the art to use the present disclosure in a variety of ways with substantially any suitable detailed structure.

[0032] This specification may use the phrases "in one embodiment," "in another embodiment," "in a further embodiment," or "in other embodiments," all of which may refer to one or more of the same or different embodiments according to the present disclosure.

[0033] Reference below Figure 1-Figure 3 The structure of the crystallization separation device of the utility model is specifically described. The crystallization device for separating nitrile compounds mainly comprises a crystallization box and internal components.

[0034] The crystallization box is composed of a horizontally placed conical cooling section 3 and a box crystallization section 4, wherein the conical cooling section 3 is in a quadrangular pyramid shape, and the box crystallization section 4 is in a rectangular shape. A material inlet 1 is provided at the conical mouth of the conical cooling section 3 for inputting nitrile-containing gas phase products, a cooling N2 inlet 2 is provided on the conical surface of the conical cooling section 3 for inputting quenching N2, a material outlet 5 is provided on the bottom wall surface of the end of the box crystallization section 4 for outputting materials, and a gas outlet 6 is provided on the end wall surface of the box crystallization section for outputting residual gas after crystallization separation;

[0035] The internal components include a crystallization unit and a support frame 8 .

[0036] Preferably, two or more support frames 8 are provided; and one or more crystallization units are provided, and the crystallization units are arranged between the support frames 8 .

[0037] Preferably, the cross section of the crystallization unit is comb-shaped, and a group of fins 9 are vertically arranged on the metal base plate 7. The fins 9 are parallel to each other. The parallel fins 9 provide sufficient attachment surfaces for nitrile compounds to desublimate, and the gaps between the fins ensure smooth passage of non-condensable gas.

[0038] The crystallization unit is carried on the support frame 8 .

[0039] Preferably, cooling N2 inlets 2 are provided on 1 to 4 conical surfaces of the conical cooling section 3, which are symmetrically distributed and used for inputting quenching N2.

[0040] Preferably, the temperature of the quenched N2 introduced through the cooling N2 inlet 2 is generally less than 10°C, and the flow rate and temperature of the cooling N2 are balanced with each other, that is, while ensuring that the gas velocity in the box is not higher than 0.1 m / s, the temperature of the quenched N2 is controlled so that the target nitrile compounds can be effectively condensed in large quantities at the mixed gas phase temperature, while other gas phase components are separated from them as much as possible.

[0041] Preferably, the angle between the conical surface of the conical cooling section 3 and the central axis is 30-75°, more preferably 40-60°, so as to facilitate the rapid reduction of gas velocity after quenching.

[0042] Preferably, the gap between the crystallization unit fins 9 is 3 to 30 mm.

[0043] Preferably, a guide rail is provided on the support frame 8 to facilitate the positioning of the crystallization unit.

[0044] Preferably, the box crystallization section 4 may be provided with a thermometer interface, a pressure gauge interface, and a safety discharge interface for monitoring the collection status of the material.

[0045] Preferably, a mirror observation port may be provided on the box crystallization section 4 for real-time monitoring of the crystallization condition on the fins.

[0046] Preferably, the crystallization unit is designed to be of a size that is easy to carry and disassemble. Multiple groups and layers of support frames 8 are provided in the box-type crystallization section 4. The crystallization units are arranged and fixed on the support frames 8. Preferably, guide rails are provided on the support frames 8 to facilitate positioning of the crystallization units. The multiple groups of crystallization units need to be evenly and compactly arranged to avoid gas phase short circuiting.

[0047] Preferably, the crystallization unit is placed parallel to the airflow direction so that the airflow flows evenly along the fin gap of the crystallization unit; during the flow of the nitrile compounds in the airflow, they are continuously condensed and precipitated on the fins, and the remaining gas phase components continue to flow to the crystallization box outlet 6.

[0048] Preferably, after the crystals are collected, the material inlet 1 is switched to introduce a solvent or steam to dissolve or melt the crystalline nitrile product from the fins 9 and output it from the material outlet 5; further preferably, the hot solvent includes but is not limited to hot water, ethylene dichloride, and dichloromethane.

[0049] Reference below Figure 1-Figure 3 The specific operation method of a novel desublimation crystallization device of the utility model is specifically described as follows:

[0050] 1) The high-temperature gas phase material containing nitrile enters the conical cooling section 3 from the material inlet 1 at the front end of the crystallization device;

[0051] 2) Cooling N2 is passed from the cooling N2 inlet 2 into the conical cooling section 3, meets the high-temperature material in step 1), the two are quickly mixed, and the high-temperature material is simultaneously quenched and cooled by N2;

[0052] 3) adjusting the temperature and flow rate of cooling N2, controlling the gas phase temperature at the end of the conical cooling section 3 to drop to the temperature range where nitrile compounds can condense and sublimate, and at the same time, the gas velocity is significantly reduced to below 0.1 m / s;

[0053] 4) The gas phase after quenching in step 3) enters the box crystallization section 4, which is filled with the crystallization units. The airflow slowly passes through the gaps between the fins 9 of the evenly distributed crystallization units. The nitrile compounds in the airflow are continuously precipitated, and the condensed crystals are continuously attached to the fins and accumulated layer by layer. The remaining gas phase components continue to flow through the gaps between the fins.

[0054] 5) The remaining gas phase components of step 4) are gathered at the gas outlet 6 at the end of the box crystallization section 4, and are output from the gas outlet 6, and the remaining gas phase composition is sampled and detected;

[0055] 6) When the collection process is completed, the cooling N2 inlet 2 is closed, and the input of high-temperature material from the material inlet 1 is stopped;

[0056] 7) switching to introduce solvent or steam from the material inlet 1, controlling the solvent temperature, dissolving or melting the crystalline nitrile product from the fins, and washing it off;

[0057] 8) After the crystals are completely detached from the crystallization unit fins 9, the material outlet 5 is opened to discharge all the materials.

[0058] Embodiment 1:

[0059] The following is a detailed description of the collection and separation process of preparing salicylic nitrile by catalytic dehydration of salicylamide. A mixed gas containing phenol, salicylic nitrile and water vapor enters the crystallization box through the material inlet 1 for collection and separation, wherein the boiling point of salicylic nitrile is 273.11°C and the freezing point is 92-95°C, the boiling point of phenol is 181.9°C and the freezing point is 40-42°C, and the temperature of the cooling N2 is below 10°C.

[0060] The specific steps are as follows:

[0061] 1) The temperature of the mixed gas containing phenol, salicylonitrile and water vapor is about 120° C. The material inlet 1 enters the conical cooling section 3;

[0062] 2) When the mixed gas in step 1) enters, cooling N2 is introduced from the four cooling N2 inlets 2 on the wall of the conical cooling section 3, and the hot mixed gas is mixed with the cooling N2 and quenched to about 80°C, and then the gas flow enters the box crystallization section 4;

[0063] 3) The gas quenched in step 2) slowly flows through the gaps between the fins 9 of the crystallization unit in the box crystallization section 4, and the salicylonitrile in the airflow adheres to the surface of the fins 9 to condense and crystallize to form a crystal layer. As the crystallization continues, the crystal layer gradually thickens;

[0064] 4) The remaining gas phase that does not crystallize in step 2) gathers at the gas outlet 6 and flows out of the system. The remaining gas phase mainly contains phenol and water vapor and a small amount of uncrystallized salicylonitrile;

[0065] 5) Controlling the mixed gas feed flow rate and temperature of the material inlet 1, and adjusting the temperature and flow rate of the cooling N2 inlet 2, the crystallization rate on the crystallization unit fin 9 and the salicylonitrile content taken out from the gas outlet 6 can be effectively controlled;

[0066] 6) When the crystal thickness on the crystal unit fin 9 reaches about 2.5 mm, stop feeding and close the cooling N2 inlet 2;

[0067] 7) The material inlet 1 is switched to introduce 120° C. steam to heat the crystallization box for discharging, and the crystalline salicylonitrile on the fins of the crystallization unit 7 is softened, dissolved, and falls off the fins, and is finally discharged from the material outlet 5 together with the condensed water.

[0068] The above embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention. The protection scope of the present invention is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present invention, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present invention.

Claims

1. A desublimation crystallization device for separating nitrile compounds, characterized in that: Its structure mainly includes: crystallization box and internal components; The crystallization box is composed of a horizontally placed conical cooling section and a box crystallization section, the conical cooling section is in a quadrangular pyramid shape, the box crystallization section is in a rectangular shape, a material inlet is provided at the conical mouth of the conical cooling section for inputting nitrile-containing gas phase products, a cooling N2 inlet is provided on the conical surface of the conical cooling section for inputting quenching N2, a material outlet is provided on the bottom wall surface of the end of the box crystallization section for outputting materials, and a gas outlet is provided on the end wall surface of the box crystallization section for outputting residual gas after crystallization separation; The internal components include a crystallization unit and a support frame.

2. The desublimation crystallization device for separating nitrile compounds according to claim 1, characterized in that: Two or more support frames are provided; one or more crystallization units are provided, and the crystallization units are arranged between the support frames.

3. The desublimation crystallization device for separating nitrile compounds according to claim 1, characterized in that: The cross section of the crystallization unit is in a comb shape, a group of fins are vertically arranged on the metal bottom plate, and the fins are parallel to each other; the crystallization unit is supported on the support frame.

4. The desublimation crystallization device for separating nitrile compounds according to claim 1, characterized in that: Cooling N2 inlets are provided on 1 to 4 conical surfaces of the conical cooling section, which are symmetrically distributed and used for inputting quenching N2.

5. The desublimation crystallization device for separating nitrile compounds according to claim 1, characterized in that: The angle between the conical surface of the conical cooling section and the central axis is 30-75°, so as to facilitate the rapid reduction of gas velocity after quenching.

6. The desublimation crystallization device for separating nitrile compounds according to claim 5, characterized in that: The angle between the conical surface of the conical cooling section and the central axis is 40-60°.

7. The desublimation crystallization device for separating nitrile compounds according to claim 1, characterized in that: The gap between the fins of the crystallization unit is 3 to 30 mm.

8. The desublimation crystallization device for separating nitrile compounds according to claim 1, characterized in that: A guide rail is provided on the support frame to facilitate the positioning of the crystallization unit.

9. The desublimation crystallization device for separating nitrile compounds according to claim 1, characterized in that: The box crystallization section is provided with a thermometer interface, a pressure gauge interface, and a safety discharge interface for monitoring the collection status of the material.

10. The desublimation crystallization device for separating nitrile compounds according to claim 1, characterized in that: The box body crystallization section is provided with a mirror observation port for real-time monitoring of the crystallization condition on the fins.

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