Device for drying cyanoacetamide

Abstract

The utility model provides a device for drying cyanoacetamide, which belongs to the technical field of cyanoacetamide production and comprises a circulating fan, a heat exchanger, an airflow dryer, a dust remover group, a condenser and a condensate receiving tank which are sequentially connected according to the flow direction of materials, and an outlet of the condensate receiving tank is connected with an inlet of the circulating fan through a circulating pipeline. A closed-loop type circulating drying system is formed; and an outlet of the heat exchanger is connected with an air inlet of the airflow dryer. By adopting the closed-loop circulating drying system, the gas recycling efficiency is greatly improved, the moisture in the tail gas is recycled, the air volume exhausted by the system is reduced, the problem that a solvent in the moisture in the tail gas with large air volume is difficult to recycle is solved, meanwhile, the treatment difficulty of the exhausted tail gas is reduced, and environment-friendly and green production is ensured.

Description

Technical Field

[0001] The utility model belongs to the technical field of cyanoacetamide production, and in particular relates to a device for drying cyanoacetamide. Background Art

[0002] Cyanoacetamide is an important organic synthesis raw material with low toxicity, no residue, and easy decomposition. It can be used to prepare a series of important drugs such as malononitrile or electroplating solution, synthesize vitamin B1, aminopterin, and triamterene. It can also synthesize benzylsulfuron, etc. It has a wide range of applications in the fields of medicine, dyes, and pesticide technology. Cyanoacetamide has the appearance of a white solid and is relatively light. It is mostly dried in the industry by airflow drying. This drying method uses a large amount of air to carry away the wet material in the system after heating it. It mainly relies on a large amount of wind to achieve the purpose of drying. However, the large air volume increases the difficulty of tail gas treatment, and the solvent contained in the wet part is not easy to recover. In today's increasingly severe environmental protection situation, this drying method is in urgent need of improvement. Utility Model Content

[0003] The utility model provides a device for drying cyanoacetamide, aiming to solve the problem that it is difficult to recover the solvent in the wet gas with a large air volume tail gas, and the problem that the large air volume increases the difficulty of tail gas treatment.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the utility model is: to provide a device for drying cyanoacetamide, comprising: a circulating fan, a heat exchanger, an air flow dryer, a dust collector group, a condenser and a condensate receiving tank connected in sequence, the outlet of the condensate receiving tank is connected to the inlet of the circulating fan through a circulating pipeline, forming a closed-loop circulating drying system; a material inlet is provided at the lower end of the air flow dryer, and the outlet of the heat exchanger is connected to the air inlet of the air flow dryer.

[0005] In one feasible manner, a drain pipe is provided on the lower side of the condensate receiving tank, a first control valve and a liquid pump are provided on the drain pipe, and a liquid level meter is also provided on the condensate receiving tank, and the liquid level meter is interlocked with the liquid pump.

[0006] In one achievable manner, the air flow dryer is provided with an oxygen content monitor, and a second control valve is provided at the material inlet of the air flow dryer, and the second control valve is interlocked with the oxygen content monitor.

[0007] In one feasible manner, the air flow dryer is provided with a gas replacement air inlet pipe, the gas replacement air inlet pipe is provided with a third control valve, a first pressure gauge is provided on the pipeline between the air flow dryer and the dust collector group, and the third control valve is interlocked with the first pressure gauge.

[0008] In one achievable manner, the dust collector group includes a cyclone dust collector and a bag dust collector which are sequentially connected in the direction of material flow.

[0009] In one achievable manner, the heat exchanger is a fin heat exchanger or a shell-and-tube heat exchanger.

[0010] In one achievable manner, the condenser is a fin-type condenser or a shell-and-tube condenser.

[0011] In one practicable manner, a thermometer is provided on the condenser.

[0012] In one achievable manner, a fourth control valve is provided on the circulation pipeline.

[0013] Compared with the prior art, the device for drying cyanoacetamide provided by the utility model has the following beneficial effects: cold air is sent to the heat exchanger through the circulating fan to be heated to form hot air, the hot air enters the airflow dryer to dry the wet material, and then enters the dust collector group, and finally enters the condenser. The condenser uses an ultra-low temperature condensation medium to condense the moisture entrained in the hot air, and the condensate enters the condensate receiving tank. The dry gas formed after the moisture is condensed continues to return to the inlet of the circulating fan through the circulating pipeline, so as to realize the closed-loop circulation drying of the entire system. The use of this closed-loop circulation drying system greatly improves the efficiency of gas recycling, recovers the moisture in the tail gas, reduces the air volume discharged from the system, solves the problem that it is difficult to recover the solvent in the moisture in the tail gas with a large air volume, and reduces the difficulty of processing the discharged tail gas, thereby ensuring environmentally friendly and green production. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic diagram of the structure of a device for drying cyanoacetamide provided in an embodiment of the utility model;

[0015] Description of reference numerals:

[0016] 1. Circulation fan; 2. Heat exchanger; 21. Heat exchanger steam inlet; 22. Heat exchanger steam outlet; 3. Air flow dryer; 31. First pressure gauge; 32. Oxygen content monitor; 33. Second control valve; 34. Gas replacement inlet pipe; 4. Cyclone dust collector; 41. First tail material outlet; 42. Fifth control valve; 43. Second pressure gauge; 5. Bag dust collector; 51. Second tail material outlet; 6. Condenser; 61. Thermometer; 7. Condensate receiving tank; 71. Drain pipe; 72. First control valve; 73. Liquid level meter; 74. Liquid pump; 8. Feeding device; 81. Third control valve; 9. Circulation pipeline; 91. Fourth control valve. DETAILED DESCRIPTION

[0017] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] In the claims, specification and the above-mentioned drawings of the utility model, unless otherwise clearly defined, the use of terms such as "first", "second" or "third" etc. is to distinguish different objects rather than to describe a specific order.

[0019] See also Figure 1 As shown, the device for drying cyanoacetamide provided by the utility model is now described. The device for drying cyanoacetamide comprises: a circulating fan 1, a heat exchanger 2, an airflow dryer 3, a dust collector group, a condenser 6 and a condensate receiving tank 7 connected in sequence according to the material flow direction, the outlet of the condensate receiving tank 7 is connected to the inlet of the circulating fan 1 through a circulating pipeline 9, forming a closed-loop circulating drying system; the lower end of the airflow dryer 3 is provided with a material inlet, and the outlet of the heat exchanger 2 is connected to the air inlet of the airflow dryer 3.

[0020] The utility model provides a device for drying cyanoacetamide, wherein an outlet of a circulating fan 1 is connected to an inlet of a heat exchanger 2, an outlet of the heat exchanger 2 is connected to an air inlet of an air flow dryer 3, a material discharge (air outlet) port of the air flow dryer 3 is connected to an inlet of a cyclone dust collector 4, an outlet of the cyclone dust collector 4 is connected to an inlet of a bag dust collector 5, an outlet of the bag dust collector 5 is connected to an inlet of a condenser 6, an outlet of the condenser 6 is connected to a condensate receiving tank 7, and an outlet of the condensate receiving tank 7 is connected to the inlet of the circulating fan 1.

[0021] According to the above connection method, cold air is sent to the heat exchanger 2 through the circulating fan 1 to be heated to form hot air. The hot air enters the air flow dryer 3 to dry the wet material and then enters the dust collector group, and finally enters the condenser 6. The condenser 6 uses an ultra-low temperature condensing medium to condense the moisture entrained in the hot air. The condensate enters the condensate receiving tank 7. The dry gas formed after the moisture is condensed continues to return to the inlet of the circulating fan 1 through the circulating pipeline 9, thereby realizing closed-loop circulation drying of the entire system.

[0022] The use of this closed-loop circulation drying system greatly improves the efficiency of gas recycling, recovers moisture in the exhaust gas, reduces the amount of air discharged from the system, and solves the problem that it is difficult to recover solvents in moisture from large exhaust gas volumes. At the same time, it reduces the difficulty of treating the emitted exhaust gas and ensures environmentally friendly, green and environmentally friendly production.

[0023] It should be noted that the airflow dryer is a hot air pulse dryer, also known as a hot air duct dryer. The advantages of this dryer are direct heating, fast drying, foldable installation, and space saving. The airflow dryer uses the principle of instant airflow drying and has the characteristics of high drying intensity, short drying time, low energy consumption, simple operation, and good product quality.

[0024] In some embodiments, a drain pipe 71 is provided on the lower side of the condensate receiving tank 7, a first control valve 72 and a liquid pump 74 are provided on the drain pipe 71, and a liquid level gauge 73 is also provided on the condensate receiving tank 7, and the liquid level gauge 73 is interlocked with the liquid pump 74. The condensate receiving tank 7 is provided with a liquid level gauge 73 and a liquid pump 74 with automatic drainage interlocking, and the liquid pump 74 is turned on when the liquid level is higher than a certain value, and is turned off when it is lower than a certain value, thereby realizing automatic adjustment of the volume of the condensate to prevent the liquid level of the condensate from being too high.

[0025] In some embodiments, an oxygen content monitor 32 is provided on the airflow dryer 3, and a second control valve 33 is provided at the material inlet of the airflow dryer 3, and the second control valve 33 is interlocked with the oxygen content monitor 32. The oxygen content monitor 32 is provided to monitor the oxygen content in the airflow dryer 3 in real time, and when the oxygen content is greater than 5%, the drying system stops feeding.

[0026] In some embodiments, a gas replacement inlet pipe 34 is provided on the airflow dryer 3, a third control valve 81 is provided on the gas replacement inlet pipe 34, a first pressure gauge 31 is provided on the pipeline between the airflow dryer 3 and the dust collector group, and the third control valve 81 is interlocked with the first pressure gauge 31.

[0027] During operation, it is necessary to first fill the system with inert gas for oxygen replacement, and then add cyanoacetamide material into the airflow dryer 3 after the oxygen content reaches below 5%; the inert gas can be common non-combustible gases such as nitrogen and helium. First, the device is circulated to replace the air, so that the oxygen content in the device drops to a certain value, and then the material is added from the material device for production, and the oxygen content in the device is automatically adjusted by interlocking to keep the oxygen content in the device not higher than a certain value. Because oxygen is a combustion-supporting gas, the oxygen content in the system directly affects the safety of production, so it is necessary to monitor the oxygen content in the system online, and interlock and stop the relevant equipment when the oxygen content exceeds the standard to ensure the safety of workers and production equipment.

[0028] When the oxygen content in the device reaches below 5%, the punching continues until the pressure reaches between 200Pa-500Pa, and the interlocking device is put into use: the system pressure is interlocked with the third control valve 81 on the gas replacement inlet pipe 34. When the pressure is lower than 200Pa, the automatic control valve opens, and when the pressure is higher than 500Pa, the automatic control valve closes to keep the pressure of the circulating air flow in the system stable.

[0029] The utility model uses inert gas as a medium to carry out cyclic drying in the system; the condenser 6 is used to condense the solvent in the gas to reduce the saturation of the circulating medium, thereby achieving the effect of cyclic drying. In addition, the entire system adds an inert gas supplement interlock setting to ensure that the system always maintains a slightly positive pressure state, and continuously supplements inert gas therein. At the same time, an oxygen content monitor 32 is set to prevent the formation of an explosive mixed gas atmosphere and improve the safety of the closed-loop drying system. According to this scheme, a closed-loop process for drying cyanoacetamide can be realized, and the dry loss of the product reaches the existing drying level, reducing the difficulty of tail gas treatment.

[0030] The application has the following beneficial effects: (1) Inert gas is used to circulate and dry in the system, effectively avoiding the formation of explosive mixtures and improving safety. (2) The recycling of tail gas reduces the tail gas emission index and the difficulty of treatment, and achieves standard emission. (3) The system is equipped with multiple interlocking controls to eliminate safety risks caused by employee operating errors. (4) The recycling of condensate realizes the recovery and reuse of solvents in wet materials.

[0031] The working process of the device is as follows: first, nitrogen is filled into the system for replacement. After the oxygen content reaches below 5%, the pressure is continued to be pressed until the pressure reaches between 200Pa and 500Pa. The interlock at the nitrogen replacement is put into use. When the pressure is lower than 200Pa, the third control valve 81 is opened, and when it is higher than 500Pa, the third control valve 81 is closed; the interlock of the oxygen content monitor 32 is also put into use to monitor the oxygen content in real time. When the oxygen content is greater than 5%, the drying system stops feeding; the condensate receiving tank 7 is provided with an automatic drainage interlock. When the liquid level is higher than a certain value, the liquid pump 74 is opened, and when it is lower than a certain value, the liquid pump 74 is closed, thereby realizing the automatic adjustment of the condensate receiving tank 7 and maintaining the stability of the liquid level in the tank. After confirming that the above interlocks are all put into use, the circulating fan 1 is turned on to transport the wet material into the drying system through the feeding device 8. According to the dry loss of the discharged material, the feeding speed can be appropriately adjusted through the third control valve 81.

[0032] In some embodiments, the dust collector group includes a cyclone dust collector 4 and a bag dust collector 5 connected in sequence according to the material flow direction. The cold air is sent to the fin heat exchanger through the fan to heat the hot air, and the hot air enters the air flow dryer 3 to dry the wet material, and then enters the cyclone dust collector and the bag dust collector 5 in sequence, and finally enters the condenser 6, and the condensate enters the condensate receiving tank 7. The dry gas formed after the moisture is condensed continues to return to the inlet of the circulating fan 1, realizing the closed-loop circulation drying of the entire system.

[0033] A first tail material outlet 41 is provided below the cyclone dust collector 4 to discharge some waste materials, and a second tail material outlet 51 is provided below the bag dust collector 5 to discharge some waste materials. Meanwhile, a second pressure gauge 43 and a fifth control valve 42 are also provided on the cyclone dust collector 4 to discharge some tail gas.

[0034] Cyclone dust collector is a type of dust removal device. The dust removal mechanism is to make the dust-laden airflow rotate, separate the dust particles from the airflow with the help of centrifugal force and capture them on the wall, and then use gravity to make the dust particles fall into the ash hopper. Cyclone dust collector and bag dust collector are two common dust removal equipment, each of which has different working principles and advantages and disadvantages:

[0035] Cyclone dust collector: The working principle is to use centrifugal force to separate dust, which is suitable for the removal of coarse particles, such as coal gangue, limestone, etc. Its advantages include simple structure, small size, low investment, and suitable for the treatment of high temperature, high humidity, and corrosive gases. The disadvantages are low filtration efficiency, especially poor filtration effect on tiny particles, and high noise.

[0036] Bag filter: The working principle is to use filter bags to filter dusty gas, which is suitable for dust removal of fine particles, such as steel, electricity, cement and other industries. Its advantages include high dust removal efficiency, which can reach more than 99.9%, suitable for filtering tiny particles, simple structure and stable operation. The disadvantages are high one-time investment cost and high maintenance cost. The replacement and cleaning of filter bags require downtime maintenance, which affects production efficiency.

[0037] The present application utilizes the mutual complementation of the cyclone dust collector 4 and the bag dust collector 5 to improve the dust removal effect. The material discharged from the air flow dryer 3 first enters the cyclone dust collector 4 to filter large particles, and then enters the bag dust collector 5 to filter small particles, thereby achieving a better dust removal effect.

[0038] In some embodiments, the heat exchanger 2 is a fin heat exchanger or a shell-and-tube heat exchanger. The heat exchanger 2 is provided with a heat exchanger steam inlet 21 and a heat exchanger steam outlet 22 .

[0039] In some embodiments, the condenser 6 is a finned condenser or a shell-and-tube condenser.

[0040] In some embodiments, a thermometer 61 is provided on the condenser 6. The condenser 6 uses an ultra-low temperature condensing medium to condense moisture entrained in the hot air. The ultra-low temperature condensing medium has a temperature range of -75°C to 30°C, preferably -20°C to 10°C.

[0041] In some embodiments, a fourth control valve 91 is provided on the circulation pipeline 9 to adjust the flow of wet air entering the circulation fan 1 .

[0042] It is explained that each control valve in the present application adopts an electrically controlled valve, and the selected pressure gauge, oxygen content monitor, thermometer and liquid level gauge can also facilitate automatic online monitoring.

[0043] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A device for drying cyanoacetamide, characterized in that, include: A circulating fan (1), a heat exchanger (2), an airflow dryer (3), a dust collector group, a condenser (6) and a condensate receiving tank (7) are connected in sequence, and the outlet of the condensate receiving tank (7) is connected to the inlet of the circulating fan (1) through a circulating pipeline (9), so as to form a closed-loop circulating drying system; a material inlet is provided at the lower end of the airflow dryer (3), and the outlet of the heat exchanger (2) is connected to the air inlet of the airflow dryer (3).

2. The device for drying cyanoacetamide as claimed in claim 1, characterized in that, A liquid discharge pipe (71) is provided on the side of the lower end of the condensate receiving tank (7), and a first control valve (72) and a liquid pump (74) are provided on the liquid discharge pipe (71). A liquid level meter (73) is also provided on the condensate receiving tank (7), and the liquid level meter (73) is interlocked with the liquid pump (74).

3. The device for drying cyanoacetamide as claimed in claim 1, characterized in that, The air flow dryer (3) is provided with an oxygen content monitor (32), and a second control valve (33) is provided at the material inlet of the air flow dryer (3), and the second control valve (33) is interlocked with the oxygen content monitor (32).

4. The device for drying cyanoacetamide as claimed in claim 1, characterized in that, The airflow dryer (3) is provided with a gas replacement air inlet pipe (34), the gas replacement air inlet pipe (34) is provided with a third control valve (81), a first pressure gauge (31) is provided on the pipeline between the airflow dryer (3) and the dust collector group, and the third control valve (81) is interlocked with the first pressure gauge (31).

5. The device for drying cyanoacetamide as claimed in claim 1, characterized in that, The dust collector group comprises a cyclone dust collector (4) and a bag dust collector (5) which are connected in sequence according to the material flow direction.

6. The device for drying cyanoacetamide as claimed in claim 1, characterized in that, The heat exchanger (2) is a fin-type heat exchanger or a shell-and-tube heat exchanger.

7. The device for drying cyanoacetamide as claimed in claim 1, characterized in that, The condenser (6) is a fin-type condenser or a shell-and-tube condenser.

8. The device for drying cyanoacetamide as claimed in claim 1, characterized in that, The condenser (6) is provided with a thermometer (61).

9. The device for drying cyanoacetamide as claimed in claim 1, characterized in that, The circulation pipeline (9) is provided with a fourth control valve (91).

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