Glyoxylic acid crystal preparation system

Abstract

The utility model provides a glyoxylic acid crystal preparation system. Comprising a first granulator used for adding induction crystals and a glyoxylic acid solution and obtaining glyoxylic acid crystals, a first screening machine used for screening out cakes in the glyoxylic acid crystals, a second granulator used for adding the screened glyoxylic acid crystals and an acetic aldehyde solution, and a cooling bin connected with the second granulator, the second screening machine is used for screening glyoxylic acid crystals into first-stage crystals, second-stage crystals and third-stage crystals, the particle sizes of the first-stage crystals, the second-stage crystals and the third-stage crystals are sequentially increased, the first-stage crystals serve as induction crystals and are conveyed to the first granulator, the second-stage crystals are conveyed to the finished product bin, the third-stage crystals are conveyed to the crusher, and the third-stage crystals are conveyed to the second screening machine. The crusher is used for treating cakes and tertiary crystals; the glyoxylic acid crystal finished product obtained by the glyoxylic acid crystal preparation system is high in quality, not easy to cake and convenient to store and transport.

Description

Technical Field

[0001] The utility model relates to the technical field of glyoxylic acid production, in particular to a glyoxylic acid crystal preparation system. Background Art

[0002] Glyoxylic acid is an important organic chemical intermediate, which is widely used in the fields of spices, medicine, paint, papermaking, fine chemicals, etc. It is an important organic chemical intermediate. With the expansion of the application field of glyoxylic acid and the development of downstream products, its market demand continues to increase. The preparation methods of glyoxylic acid mainly include oxalic acid electrolytic reduction method and glyoxal nitric acid oxidation method. The oxalic acid electrolytic reduction method has the disadvantages of poor cation exchange membrane performance, large solution volatilization and unsatisfactory electrode materials. The glyoxal nitric acid oxidation method inevitably has equipment corrosion and environmental pollution problems, and the glyoxylic acid aqueous solution prepared is 30-50%. There is a large amount of water in the glyoxylic acid aqueous solution, and it contains a large amount of aldehyde impurities such as glyoxal, which is difficult to meet the demand for industrial high-purity solid glyoxylic acid.

[0003] In an existing method for preparing glyoxylic acid, maleic anhydride is used as a raw material, maleic anhydride is hydrolyzed to form maleic acid, ozone is introduced for oxidation to obtain glyoxylic acid, and then after steps such as impurity removal and concentration, high-purity glyoxylic acid solutions of different concentrations can be obtained, which can meet the requirements of downstream products for high-purity glyoxylic acid. However, the glyoxylic acid aqueous solution is very easy to darken in color during storage, affecting its use, and the aqueous solution is inconvenient to transport and has high costs. Another existing technology crystallizes glyoxylic acid from an aqueous solution, and the product is a large block, or the large block is broken, which increases the processing cost, has different shapes, and is not conducive to packaging and transportation. After breaking and packaging, the broken blocks squeeze and rub against each other, forming a large amount of powdered glyoxylic acid, which is easy to aggregate into large blocks, causing great inconvenience to the use of downstream products. Utility Model Content

[0004] In order to solve the problems existing in the prior art, the utility model provides a glyoxylic acid crystal preparation system.

[0005] A glyoxylic acid crystal preparation system provided by the utility model comprises:

[0006] a first granulator, which is used to add the induction crystals and the glyoxylic acid solution and obtain glyoxylic acid crystals;

[0007] a first screening machine connected to the first granulator and used to screen out lumps in the glyoxylic acid crystals;

[0008] a second granulator connected to the first screening machine and used to add the glyoxylic acid crystals and acetic acid aldehyde solution screened by the first screening machine;

[0009] A cooling silo connected to the second granulator;

[0010] a second screening machine connected to the cooling silo;

[0011] a finished product silo connected to the second screening machine;

[0012] A crusher, connected to the first screening machine and the second screening machine respectively;

[0013] The second screening machine is configured to: screen the glyoxylic acid crystals into primary crystals, secondary crystals and tertiary crystals with successively increasing particle sizes, convey the primary crystals as induced crystals to the first granulator, convey the secondary crystals to the finished product silo, and convey the tertiary crystals to the crusher; the crusher is configured to process the agglomerates and the tertiary crystals.

[0014] In one embodiment of the present invention, the first granulator and the second granulator are respectively equipped with an air-cooled drying device.

[0015] In one embodiment of the present invention, a first screw conveyor and a first elevator for conveying glyoxylic acid crystals are arranged between the second granulator and the cooling silo.

[0016] In one embodiment of the present invention, a second screw conveyor and a second elevator for conveying glyoxylic acid crystals are provided between the cooling bin and the second screening machine.

[0017] In one embodiment of the utility model, it also includes a buffer bin and a third screw conveyor. The buffer bin is connected to the second screening machine and is used to hold the primary crystals. The buffer bin conveys the primary crystals to the first granulator through the third screw conveyor.

[0018] A beneficial effect of the utility model is that the glyoxylic acid crystals obtained after the glyoxylic acid solution is processed by the first granulator and the second granulator of the glyoxylic acid crystal preparation system are of high quality and less small particle crystals, the first screening machine can screen out agglomerates to improve the crystal quality, the second screening machine screens the glyoxylic acid crystals that have passed through the cooling silo into secondary crystals that meet the finished product standard, the screened primary crystals with a particle size smaller than the finished product standard are sent to the first granulator as induced crystals for circulation crystallization, and the screened tertiary crystals with a particle size larger than the finished product standard are sent to the crusher for crushing; the glyoxylic acid crystals finally obtained have high quality, are not easy to agglomerate, and are convenient for the storage and transportation of glyoxylic acid.

[0019] Other features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention.

[0021] Figure 1 The utility model provides a schematic diagram of the overall structure of a glyoxylic acid crystal preparation system.

[0022] Figure 1 The one-to-one correspondence between the component names and the reference numerals is as follows:

[0023] 1. The first granulator; 2. The first screening machine; 3. The second granulator; 4. The cooling silo; 5. The second screening machine; 6. The finished product silo; 7. The crusher; 8. The first screw conveyor; 9. The first elevator; 10. The second screw conveyor; 11. The second elevator; 12. The buffer silo; 13. The third screw conveyor. DETAILED DESCRIPTION

[0024] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0025] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present invention, its application, or uses.

[0026] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0027] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0028] In this article, "first", "second", etc. are only used to distinguish each other, and do not indicate the importance and order, or the premise of each other's existence.

[0029] In this document, “equal”, “same”, etc. are not strictly limited in a mathematical and / or geometric sense, but also include errors that can be understood by those skilled in the art and are allowed in manufacturing or use.

[0030] In this document, unless otherwise specified, "plurality" means two or more. Unless otherwise specified, the numerical ranges herein include not only the entire ranges within the two endpoints thereof, but also several sub-ranges contained therein.

[0031] The utility model provides a system for preparing glyoxylic acid crystals. Figure 1 As shown, it includes a first granulator 1, a first screening machine 2, a second granulator 3, a cooling silo 4, a second screening machine 5, a finished product silo 6 and a crusher 7.

[0032] The first granulator 1 is used to obtain glyoxylic acid crystals by treating the glyoxylic acid solution with induced crystals. A selected proportion of induced crystals is added to the first granulator 1, and the induced crystals and the glyoxylic acid solution are mixed and crystallized in the first granulator 1 to obtain glyoxylic acid crystals. Specifically, the first granulator 1 is a drum granulator, and the mass of the selected induced crystal seeds is 9 times the mass of the 80% glyoxylic acid solution. The glyoxylic acid induced crystals are added to the first granulator 1, and the glyoxylic acid solution is sprayed into the first granulator 1 through a spray gun to perform solid-liquid mixing and gradual crystallization.

[0033] The first screening machine 2 is connected to the first granulator 1. The glyoxylic acid crystals produced by the first granulator 1 are fed into the first screening machine 2. The first screening machine 2 is used to preliminarily screen out the agglomerates in the glyoxylic acid crystals. Since the acetic acid aldehyde solution contains a lot of water, the acetic acid aldehyde crystals produced by the first granulator 1 have poor dryness, small crystal size, and are prone to agglomeration. Screening out the agglomerates by the first screening machine 2 can improve the product quality of the acetic acid aldehyde crystals.

[0034] The second granulator 3 is connected to the first screening machine 2, and is used to add the glyoxylic acid crystals screened by the first screening machine and the acetic acid aldehyde solution. Specifically, the second granulator 3 also adopts a drum-type granulator, adds the glyoxylic acid crystals and further sprays the glyoxylic acid solution through a spray gun, further performs solid-liquid mixing and crystallization, which can improve the quality of the acetic acid aldehyde crystals and obtain higher quality glyoxylic acid crystals.

[0035] Furthermore, the first granulator 1 and the second granulator 3 are respectively provided with an air-cooled drying device, which sends dry cold air flow into the first granulator 1 and the second granulator 3 to cool and dry the glyoxylic acid, thereby reducing the agglomeration of glyoxylic acid crystals, thereby improving work efficiency and product quality.

[0036] Specifically, the air-cooled drying device includes a fan and a refrigeration assembly, and the refrigeration assembly includes an evaporator, a compressor connected to one end of the evaporator, and a condenser connected to the other end of the evaporator. The evaporator, the compressor and the condenser form a closed loop. The coolant evaporates and absorbs heat in the evaporator, so that the air outside the evaporator is cooled to form a cold air flow, which is extracted by the fan and sent to the drum of the first granulator 1 / the second granulator 3.

[0037] The cooling silo 4 is connected to the second granulator 3, and the glyoxylic acid crystals obtained by the second granulator 3 are sent to the cooling silo 4 for cooling and storage. Specifically, a first screw conveyor 8 and a first elevator 9 for conveying the glyoxylic acid crystals are provided between the second granulator 3 and the cooling silo 4. The glyoxylic acid crystals produced by the second granulator 3 are conveyed to the first elevator 9 by the first screw conveyor 8, and the first elevator 9 conveys the glyoxylic acid crystals into the cooling silo 4.

[0038] The second screening machine 5 is connected to the cooling silo 4, and is used to further screen the cooled glyoxylic acid crystals. The second screening machine 5 is configured to screen the glyoxylic acid crystals into primary crystals, secondary crystals and tertiary crystals with increasing particle sizes, and to transport the primary crystals as induced crystals to the first granulator 1, the secondary crystals to the finished product silo 6, and the tertiary crystals to the crusher 7.

[0039] Specifically, the crystals with a particle size of less than 2.5 mm are primary crystals, the crystals with a particle size between 2.5 and 4 mm are secondary crystals, and the crystals with a particle size of more than 4 mm are tertiary crystals. Among them, the secondary crystals are product grade, meet product standards, and can be sent to the finished product silo 6, and then enter the packaging link. The primary crystals have a smaller particle size and can be sent to the first granulator 1 as induced crystals to continue mixing with the glyoxylic acid solution, thereby circulating the crystallization process. The large-sized tertiary crystals can be sent to the crusher 7 for crushing.

[0040] Specifically, a second screw conveyor 10 and a second elevator 11 for conveying glyoxylic acid crystals are provided between the cooling bin 4 and the second screening machine 5. The glyoxylic acid crystals in the cooling bin 4 are conveyed to the second elevator 11 by the second screw conveyor 10, and the second elevator 11 conveys the glyoxylic acid crystals into the second screening machine 5.

[0041] The crusher 7 is connected to the first screening machine 2 and the second screening machine 5 respectively. The first screening machine 2 sends the agglomerates screened out from the acetic acid aldehyde crystals to the crusher 7 for crushing, and the second screening machine 5 sends the tertiary crystals screened out to the crusher 7 for crushing. The crusher 7 can crush the agglomerates or tertiary crystals of the acetic acid aldehyde crystals into particles of less than 2.5 mm. The crusher 7 can be connected to the first granulator 1 to send the crushed crystals as induced crystals to the first granulator 1.

[0042] Specifically, the second screening machine 5 is connected to a buffer bin 12 for holding the primary crystals, and the buffer bin 12 is connected to the first granulator 1 through a third screw conveyor 13 to convey the primary crystals to the first granulator 1. The crusher 7 can be connected to the third screw conveyor 13 to convey the crushed acetic acid aldehyde crystals into the first granulator 1 through the third screw conveyor 13.

[0043] The glyoxylic acid crystal preparation system provided by the utility model can prepare a stable glyoxylic acid solid product. After the solid is dissolved in water, it becomes a colorless aqueous solution, which greatly guarantees the quality of the glyoxylic acid and facilitates the storage and transportation of the glyoxylic acid.

[0044] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein. The scope of the present invention is defined by the appended claims.

Claims

1. A system for preparing glyoxylic acid crystals, characterized in that: include: a first granulator, which is used to add the induction crystals and the glyoxylic acid solution and obtain glyoxylic acid crystals; a first screening machine connected to the first granulator and used to screen out lumps in the glyoxylic acid crystals; a second granulator connected to the first screening machine and used to add the glyoxylic acid crystals and acetic acid aldehyde solution screened by the first screening machine; A cooling silo connected to the second granulator; a second screening machine connected to the cooling silo; a finished product silo connected to the second screening machine; A crusher, connected to the first screening machine and the second screening machine respectively; The second screening machine is configured to: screen the glyoxylic acid crystals into primary crystals, secondary crystals and tertiary crystals with successively increasing particle sizes, convey the primary crystals as induced crystals to the first granulator, convey the secondary crystals to the finished product silo, and convey the tertiary crystals to the crusher; the crusher is configured to process the agglomerates and the tertiary crystals.

2. The system for preparing glyoxylic acid crystals according to claim 1, characterized in that: The first granulator and the second granulator are respectively equipped with an air-cooled drying device.

3. The system for preparing glyoxylic acid crystals according to claim 1, characterized in that: A first screw conveyor and a first elevator for conveying glyoxylic acid crystals are arranged between the second granulator and the cooling silo.

4. The system for preparing glyoxylic acid crystals according to claim 1, characterized in that: A second screw conveyor and a second elevator for conveying glyoxylic acid crystals are arranged between the cooling bin and the second screening machine.

5. The system for preparing glyoxylic acid crystals according to claim 1, characterized in that: It also includes a buffer bin and a third screw conveyor. The buffer bin is connected to the second screening machine and is used to hold the primary crystals. The buffer bin conveys the primary crystals to the first granulator through the third screw conveyor.

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