Chemical device for measuring crystallization point in adipic acid production

Abstract

The utility model relates to the technical field of chemical equipment, in particular to a chemical device for measuring a crystallization point in adipic acid production. The device comprises a measuring tank, a coil pipe, a temperature measuring instrument, a high-temperature water path, a material pipeline, a cooling water path and a material storage tank, the high-temperature water path and one end, facing the measuring tank, of the material pipeline intersect and converge into a confluence pipeline; the tail end of the confluence pipeline is connected with a top inlet of the measuring tank; the coil pipe is arranged in the measuring tank and is spirally arranged along the inner wall of the measuring tank, the cooling water path is connected with an inlet of the coil pipe, and an outlet of the coil pipe extends out of the measuring tank; the temperature measuring instrument is mounted in the measuring tank, and a stirring piece is arranged in the measuring tank; a gas outlet is formed in the top of the measuring tank; a bottom outlet of the measuring tank is connected with the material storage tank through a discharge pipeline. The utility model effectively solves the technical problem that the measurement of the crystallization point is inaccurate due to small effective heat exchange area when the measurement device in the prior art is used for measuring the crystallization point of adipic acid in a jacketed heating manner.

Description

Technical Field

[0001] This utility model relates to the field of chemical equipment technology, and in particular to a chemical device for measuring the crystallization point in the production of adipic acid. Background Technology

[0002] Adipic acid, also known as fatty acid, is an important organic dicarboxylic acid with the structural formula HOOC(CH2)4COOH. It can undergo salt formation, esterification, and amidation reactions, and can condense with diamines or diols to form high molecular weight polymers. Adipic acid plays a vital role in chemical production, organic synthesis, pharmaceuticals, and lubricant manufacturing.

[0003] Traditional methods for measuring the crystallization point of adipic acid during production require manual sampling and waiting for the solution to cool before measurement. This method is time-consuming and prone to errors, resulting in low accuracy. To address this, patent document CN203551487U discloses an automatic crystallization point analyzer for adipic acid solution. This analyzer includes a measuring container, an outer jacket, a feed valve, a stirrer, a thermometer, a drain valve, and a vent pipe. The outer jacket is located on the side wall of the measuring container and is equipped with a jacket steam / water inlet valve and a jacket steam / water return valve. The feed valve is located on the upper part of the side wall of the measuring container, the drain valve is located at the bottom of the measuring container, the stirrer is located in the middle of the measuring container, the thermometer is located near the side wall of the measuring container, and the vent pipe is located at the top of the measuring container.

[0004] As can be seen, the aforementioned measuring device can achieve online measurement of the crystallization point of adipic acid using a thermometer, and can dissolve the crystallizing adipic acid by introducing steam into the outer jacket, preventing crystallization on the inner wall of the measuring device container before the next sample solution enters the container. However, the aforementioned measuring device heats and dissolves the measuring device container through the outer jacket. The heat exchange area of ​​the outer jacket is limited by the area of ​​the outer wall of the container, resulting in a small effective heat exchange area and poor heat exchange effect. This cannot effectively melt the crystals, which not only leads to inaccurate crystallization point measurements but also requires frequent cleaning of the measuring device container during subsequent use, significantly increasing downtime and affecting the production efficiency of adipic acid. Utility Model Content

[0005] This invention provides a chemical apparatus for measuring the crystallization point in adipic acid production, which solves the technical problem that the existing measuring device uses jacket heating when measuring the crystallization point of adipic acid, resulting in a small effective heat exchange area and inaccurate crystallization point measurement.

[0006] To solve the above problems, the chemical apparatus for measuring the crystallization point in adipic acid production provided by this utility model adopts the following technical solution:

[0007] A chemical apparatus for measuring the crystallization point in adipic acid production includes a measuring tank, a coil, a temperature measuring instrument, a high-temperature water circuit, a material pipeline, a cooling water circuit, and a material storage tank.

[0008] The high-temperature water circuit intersects with the material pipeline at one end facing the measuring tank and merges into the manifold, the end of which is connected to the top inlet of the measuring tank.

[0009] The coil is installed inside the measuring tank and arranged in a spiral shape along the inner wall of the measuring tank. The cooling water circuit is connected to the inlet of the coil, and the outlet of the coil extends to the outside of the measuring tank.

[0010] The temperature measuring instrument is installed inside the measuring tank, and the measuring tank is equipped with a stirring element;

[0011] The measuring tank has an air outlet at the top, and the bottom outlet of the measuring tank is connected to the material storage tank through a discharge pipeline.

[0012] The beneficial effects of the chemical apparatus for measuring the crystallization point in adipic acid production provided by this utility model are:

[0013] 1. By installing a coil arranged in a spiral shape along the inner wall of the measuring tank, the coil provides a larger heat transfer area in the measuring tank. The flow path of the cooling water in the coil is tortuous, which will generate secondary flow, enhance the degree of turbulence, and make the heat transfer more complete. Under turbulent conditions, the heat exchange efficiency between the cooling water and the coil is much higher than that of laminar flow, which helps to break the boundary layer, reduce thermal resistance, and rapidly cool down the material in the measuring tank to reach the crystallization point temperature, thereby improving the accuracy of crystallization point measurement.

[0014] 2. By setting up a high-temperature water path, high-temperature water can be introduced into the measuring tank after the crystallization point measurement is completed. This quickly melts and removes any residual crystals in the measuring tank, preventing the crystals from interfering with the temperature measurement during the next crystallization point measurement and thus improving the accuracy of the crystallization point measurement.

[0015] Through the above-mentioned design, this utility model effectively solves the technical problem in the prior art where the measuring instrument uses jacket heating to measure the crystallization point of adipic acid, resulting in a small effective heat exchange area and inaccurate crystallization point measurement.

[0016] Furthermore, valves are installed on the high-temperature water circuit, the material pipeline, the cooling water circuit, and the discharge pipeline.

[0017] Furthermore, the valve, the temperature measuring instrument, and the stirring component are all connected to the automatic control system via signals.

[0018] Furthermore, the automatic control system is a distributed control system.

[0019] Furthermore, a level gauge is installed inside the measuring tank.

[0020] Furthermore, the air outlet is connected to an air outlet pipeline, and an induced draft fan is installed on the air outlet pipeline.

[0021] Furthermore, an overflow hole is provided on the upper side wall of the measuring tank, and the overflow hole is connected to the material storage tank through an overflow pipe.

[0022] Furthermore, a regulating valve is provided on the cooling water circuit.

[0023] Furthermore, the stirring element extends to the middle of the measuring vessel.

[0024] Furthermore, the temperature measuring instrument is a thermometer. Attached Figure Description

[0025] The above and other objects, features, and advantages of the present invention will become readily understood by reading the following detailed description of exemplary embodiments with reference to the accompanying drawings. In the drawings, several embodiments of the present invention are shown by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein:

[0026] Figure 1 This is a schematic diagram of the chemical apparatus for measuring the crystallization point in the production of adipic acid, provided by this utility model.

[0027] Explanation of reference numerals in the attached figures:

[0028] 1. Measuring tank; 2. Coil; 3. Temperature measuring instrument; 4. High-temperature water circuit; 5. Material pipeline; 6. Cooling water circuit; 7. Manifold; 8. Discharge pipeline; 9. Agitator; 10. Valve; 11. Level gauge; 12. Gas outlet pipeline; 13. Exhaust fan; 14. Overflow pipeline; 15. Regulating valve. Detailed Implementation

[0029] The principles and spirit of this utility model will be explained in detail below with reference to several representative embodiments.

[0030] An embodiment of the chemical apparatus for measuring the crystallization point in adipic acid production provided by this utility model:

[0031] like Figure 1 As shown, the chemical equipment for measuring the crystallization point in adipic acid production includes a measuring tank 1, a coil 2, a temperature measuring instrument 3, a high-temperature water circuit 4, a material water circuit, a cooling water circuit 6, and a material storage tank (not shown in the figure).

[0032] The high-temperature water pipeline and the material pipeline 5 intersect at their right ends and merge into the manifold 7. The end of the manifold 7 is connected to the top inlet of the measuring tank 1. The coil 2 is installed inside the measuring tank 1 and is arranged in a spiral shape along the inner wall of the measuring tank 1. The cooling water line 6 is connected to the inlet of the coil 2, and the outlet of the coil 2 extends to the outside of the measuring tank 1. The temperature measuring instrument 3 is installed inside the measuring tank 1. The measuring tank 1 is equipped with a stirring element 9. The top of the measuring tank 1 has an air outlet, and the bottom outlet of the measuring tank 1 is connected to the material storage tank through the discharge pipeline 8.

[0033] In this embodiment, valves 10 are installed on the high-temperature water circuit 4, material pipeline 5, cooling water circuit 6, and discharge pipeline 8. A level gauge 11 is installed inside the measuring tank 1. The top of the measuring tank 1 has an air outlet, which is connected to an air outlet pipeline 12. An induced draft fan 13 is installed on the air outlet pipeline 12. The valves 10, temperature measuring instrument 3, level gauge 11, induced draft fan 13, and stirring component 9 are all connected to the automatic control system (not shown in the figure). In this embodiment, all valves 10 are solenoid valves, and the automatic control system is a distributed control system.

[0034] In addition, in this embodiment, an overflow hole is provided on the upper side wall of the measuring tank 1, and the overflow hole is connected to the material storage tank through an overflow pipe 14; a regulating valve 15 is provided on the cooling water circuit 6, and the regulating valve 15 is connected to the automatic control system signal; the stirring component 9 extends to the middle of the measuring tank 1; the temperature measuring instrument 3 is a thermometer. In other embodiments, the temperature measuring instrument 3 is an infrared thermometer.

[0035] It should be noted that the production of adipic acid requires a reaction between nitric acid and cyclohexanol. To ensure complete participation of cyclohexanol in the reaction, excess nitric acid is used. The ratio of cyclohexanol to nitric acid affects the concentration of the resulting solution. If the concentration is too high, the crystallization point will be low, which can easily clog the pipeline. If the crystallization point is too low, there will be excess nitric acid, increasing consumption. Furthermore, an excessively low concentration is also detrimental to the operation of subsequent systems. Therefore, measuring the crystallization point of the adipic acid solution can directly reflect its concentration, and the ratio of nitric acid can be adjusted accordingly.

[0036] The working principle of the chemical device for measuring the crystallization point in adipic acid production provided by this utility model is as follows: First, the valve 10 of the material pipeline 5 is opened, and the adipic acid solution enters the measuring tank 1 through the material pipeline 5. When the level gauge 11 detects that the liquid level of the material in the measuring tank 1 is greater than 50% of the height of the measuring tank 1, the stirring element 9 is started to make the material temperature in the measuring tank 1 uniform.

[0037] The temperature of the material in measuring tank 1 is observed by a temperature detector. If the temperature of the material is still rising, the feeding time can be extended until the temperature of the material in measuring tank 1 is stable. Excess material enters the material storage tank through the overflow hole and overflow pipe 14.

[0038] Once the material temperature in measuring tank 1 stabilizes, control the closure of valve 10 in material pipeline 5 and the opening of valve 10 in cooling pipeline. Cooling water enters coil 2 through cooling pipeline to cool the material. The cooling rate is adjusted by control regulating valve 15. When the temperature of the material in measuring tank 1 shows a smooth end or a brief rise during the temperature drop, the current temperature can be determined as the crystallization point. After the crystallization point measurement is completed, control the closure of valve 10 in cooling water pipeline 6 and the opening of valve 10 in high-temperature water pipeline 4 to introduce hot water into measuring tank 1. The hot water dilutes and dissolves the crystals formed in measuring tank 1. Then, open valve 10 in discharge pipeline 8, and the material in measuring tank 1 is discharged into the material storage tank. When the level gauge 11 detects that the liquid level of the material in measuring tank 1 is below 50%, control the agitator 9 to stop.

[0039] During the measurement of the crystallization point, the blower 13 draws gas from the measuring tank 1, making the measuring tank 1 under a slight negative pressure. The extracted exhaust gas is then purified by the treatment system.

[0040] Based on the above description in this specification, those skilled in the art will also understand that the following terms used, such as "upper," "lower," "front," "rear," "left," "right," "width," "horizontal," "top," "bottom," "inner," and "outer," are terms indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings of this specification. They are only for the purpose of facilitating the explanation of the present invention and simplifying the description, and do not explicitly or implicitly suggest that the device or element involved must have the specific orientation, or be constructed and operated in a specific orientation. Therefore, the above-mentioned orientation or positional relationship terms should not be understood or interpreted as limitations on the present invention.

[0041] In addition, in the description of this specification, "multiple" means at least two, such as two, three or more, etc., unless otherwise expressly and specifically defined.

Claims

1. A chemical apparatus for measuring the crystallization point in adipic acid production, characterized in that, This includes measuring tanks, coils, temperature measuring instruments, high-temperature water circuits, material pipelines, cooling water circuits, and material storage tanks; The high-temperature water circuit intersects with the material pipeline at one end facing the measuring tank and merges into the manifold, the end of which is connected to the top inlet of the measuring tank. The coil is installed inside the measuring tank and arranged in a spiral shape along the inner wall of the measuring tank. The cooling water circuit is connected to the inlet of the coil, and the outlet of the coil extends to the outside of the measuring tank. The temperature measuring instrument is installed inside the measuring tank, and a stirring element is provided inside the measuring tank. The measuring tank has an air outlet at the top, and the bottom outlet of the measuring tank is connected to the material storage tank through a discharge pipeline.

2. The chemical apparatus for measuring the crystallization point in adipic acid production according to claim 1, characterized in that, Valves are installed on the high-temperature water circuit, the material pipeline, the cooling water circuit, and the discharge pipeline.

3. The chemical apparatus for measuring the crystallization point in adipic acid production according to claim 2, characterized in that, The valve, the temperature measuring instrument, and the stirring component are all connected to the automatic control system via signal transmission.

4. The chemical apparatus for measuring the crystallization point in adipic acid production according to claim 3, characterized in that, The automatic control system is a distributed control system.

5. The chemical apparatus for measuring the crystallization point in adipic acid production according to any one of claims 1 to 4, characterized in that, The measuring tank is equipped with a level gauge.

6. The chemical apparatus for measuring the crystallization point in adipic acid production according to any one of claims 1 to 4, characterized in that, The air outlet is connected to an air outlet pipeline, and an induced draft fan is installed on the air outlet pipeline.

7. The chemical apparatus for measuring the crystallization point in adipic acid production according to any one of claims 1 to 4, characterized in that, An overflow hole is provided on the upper side wall of the measuring tank, and the overflow hole is connected to the material storage tank through an overflow pipe.

8. The chemical apparatus for measuring the crystallization point in adipic acid production according to any one of claims 1 to 4, characterized in that, A regulating valve is installed on the cooling water line.

9. The chemical apparatus for measuring the crystallization point in adipic acid production according to any one of claims 1 to 4, characterized in that, The stirring element extends to the middle of the measuring vessel.

10. The chemical apparatus for measuring the crystallization point in adipic acid production according to any one of claims 1 to 4, characterized in that, The temperature measuring instrument is a thermometer.

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