Dichloromethane refining device

Abstract

The utility model discloses a dichloromethane refining device, which relates to the technical field of chemical engineering, and comprises a first condenser, an oil-water separator, a first drying kettle and a receiving tank, the oil-water separator is positioned between the first condenser and the first drying kettle, the first drying kettle is positioned between the receiving tank and the oil-water separator, the receiving tank is also connected with a delivery pump, and the delivery pump is connected with the oil-water separator. The first condenser, the oil-water separator, the first drying kettle and the receiving tank are sequentially connected through pipelines. Therefore, after the tail gas containing dichloromethane is deeply condensed by the first condenser, the dichloromethane is converted from a gaseous state to a liquid state, then the liquid dichloromethane is refined by the oil-water separator and the first drying kettle, dehydration is completed, and the dichloromethane recovery work is completed. And the environmental pollution caused by the emission of dichloromethane is reduced.

Description

TECHNICAL FIELD

[0001] The utility model is suitable for chemical technology field, provide a kind of methylene chloride refining device. BACKGROUND

[0002] In the production of BE acid, the chlorobenzene used can be replaced by dichloromethane.

[0003] Because BE acid needs to be kept at high temperature during production, the dichloromethane used in the production process will evaporate due to high temperature and be discharged with tail gas. Dichloromethane has a pungent odor, so if it is discharged directly, it will not only harm the surrounding environment, but also cause waste of raw materials. Therefore, we need to recover dichloromethane.

[0004] However, the existing recovery technology is difficult to purify dichloromethane, which results in the recovery of dichloromethane mixed with impurities and cannot be reused. UTILITY MODEL CONTENT

[0005] In view of the above defects, the utility model aims to provide a dichloromethane refining device to solve the problems in the background.

[0006] A dichloromethane refining device, comprising a first condenser, an oil-water separator, a first drying kettle and a receiving tank, the oil-water separator is located between the first condenser and the first drying kettle, the first drying kettle is located between the receiving tank and the oil-water separator, the receiving tank is also connected with a delivery pump, the first condenser, the oil-water separator, the first drying kettle and the receiving tank are connected in sequence.

[0007] Among them, the second condenser is arranged between the first condenser and the oil-water separator, and the second condenser is connected with the oil-water separator.

[0008] Among them, the oil-water separator is also connected with a third condenser.

[0009] Among them, the alkali washing tower is arranged between the oil-water separator and the first drying kettle, and the alkali washing tower is connected with the oil-water separator and the first drying kettle respectively.

[0010] Among them, the water washing tower is arranged between the alkali washing tower and the first drying kettle, and the water washing tower is connected with the alkali washing tower and the first drying kettle respectively.

[0011] Among them, the first rectifying tower and the first rotary plate condenser are arranged between the water washing tower and the first drying kettle, and the water washing tower, the first rectifying tower, the first rotary plate condenser and the first drying kettle are connected in sequence.

[0012] The first rectification tower is further connected with a second rectification tower, the second rectification tower is further connected with an ethylbenzene storage tank and a benzene receiving tank, and a second rotating plate type condenser is arranged between the second rectification tower and the benzene receiving tank.

[0013] The first drying kettle is provided with a second drying kettle between the first drying kettle and the receiving tank.

[0014] Advantages

[0015] The tail gas containing dichloromethane is deeply condensed by the first condenser, and the dichloromethane is converted from gaseous state to liquid state, then the liquid dichloromethane is refined by the oil-water separator and the first drying kettle to complete dehydration, and the dichloromethane recovery is completed, which reduces the cost and reduces the environmental pollution caused by dichloromethane emission. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a structure diagram of the dichloromethane refining device.

[0017] In the figure: 1-first condenser, 2-second condenser, 3-third condenser, 4-oil-water separator, 5-alkali washing tower, 6-water washing tower, 7-first rectification tower, 8-first rotating plate type condenser, 9-second rectification tower, 10-second rotating plate type condenser, 11-benzene receiving tank, 12-ethylbenzene storage tank, 13-first drying kettle, 14-second drying kettle, 15-receiving tank, 16-conveying pump, 17-tail gas receiving pipeline. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the utility model more clear, the utility model is further described in detail below with reference to the drawings. It should be understood that the specific embodiments described herein are only used to explain the utility model, and are not used to limit the utility model.

[0019] Embodiment:

[0020] Dichloromethane has very low boiling point, therefore, the dichloromethane is deeply condensed in the present scheme, so that it is converted from gaseous state to liquid state, to facilitate dichloromethane recovery. For this purpose, see Figure 1A dichloromethane refining device, comprising a first condenser 1, an oil-water separator 4, a first drying kettle 13 and a receiving tank 15, wherein the oil-water separator 4 is located between the first condenser 1 and the first drying kettle 13, the first drying kettle 13 is located between the receiving tank 15 and the oil-water separator 4, the receiving tank 15 is further connected with a delivery pump 16, and the first condenser 1, the oil-water separator 4, the first drying kettle 13 and the receiving tank 15 are sequentially connected by pipelines. The first condenser 1 is connected with a tail gas receiving pipeline 17 for receiving tail gas containing dichloromethane from a desolventizing tower. Then, the tail gas is circulated and condensed in the first condenser 1, and dichloromethane, benzene, toluene, ethylbenzene, water and other materials in the tail gas are all changed into liquid state, the condensed solution enters the oil-water separator 4, water and other materials are separated by the different concentration of the solution, and then the water is discharged to preliminarily dehydrate the solution. After the preliminary dehydration, the solution reaches the first drying kettle 13 for secondary dehydration to obtain a more concentrated solution, and the concentration of dichloromethane in the solution is above 90%. Finally, the solution is sent to the receiving tank 15 for use.

[0021] In the scheme, the delivery pump 16 provides power for the flow of the solution from the first drying kettle 13 to the receiving tank 15.

[0022] Since the boiling point of dichloromethane is extremely low, the tail gas treated by the first condenser 1 still contains some gaseous dichloromethane. In order to further recover the dichloromethane, a second condenser 2 is arranged between the first condenser 1 and the oil-water separator 4, and the second condenser 2 is connected with the oil-water separator 4 by a pipeline.

[0023] When the ambient temperature is high, part of the dichloromethane in the oil-water separator 4 will become gaseous. In order to recover the dichloromethane, the oil-water separator 4 is further connected with a third condenser 3 by a pipeline. The third condenser 3 is in communication with the oil-water separator 4, the dichloromethane in the oil-water separator 4 changes from liquid state to gaseous state after being heated, the gaseous dichloromethane enters the third condenser 3 after expansion, the third condenser 3 continuously condenses the gas, and the condensed product is sent back to the oil-water separator 4.

[0024] Since there is still some hydrochloric acid in the tail gas, the hydrochloric acid will be condensed into liquid state together. In order to remove the hydrochloric acid, an alkali washing tower 5 is arranged between the oil-water separator 4 and the first drying kettle 13, and the alkali washing tower 5 is connected with the oil-water separator 4 and the first drying kettle 13 by pipelines respectively.

[0025] After the alkali washing, some alkali solution remains in the solution. In order to remove the alkali solution, a water washing tower 6 is arranged between the alkali washing tower 5 and the first drying kettle 13, and the water washing tower 6 is connected with the alkali washing tower 5 and the first drying kettle 13 by pipelines respectively.

[0026] The solution after water washing still has some impurities (such as benzene, toluene, ethylbenzene), in order to remove the part of impurities, a first rectifying tower 7, a first rotating plate condenser 8 are arranged between the water washing tower 6 and the first drying kettle 13, and the water washing tower 6, the first rectifying tower 7, the first rotating plate condenser 8 and the first drying kettle 13 are sequentially connected by pipelines. The first rectifying tower 7 rectifies the solution, in the process, the dichloromethane becomes gaseous, the gaseous dichloromethane reaches the first rotating plate condenser 8 and is converted into liquid state, and then the liquid dichloromethane is sent to the first drying kettle 13 for dehydration.

[0027] In order to recover benzene from the impurities, the first rectifying tower 7 is further connected with a second rectifying tower 9, the second rectifying tower 9 is further connected with an ethylbenzene storage tank 12 and a benzene receiving tank 11, and a second rotating plate condenser 10 is arranged between the second rectifying tower 9 and the benzene receiving tank 11. After the impurities are rectified by the second rectifying tower 9, the benzene reaches the second rotating plate condenser 10 and is then temporarily stored in the benzene receiving tank 11. The ethylbenzene in the impurities is temporarily stored in the ethylbenzene storage tank 12.

[0028] In order to ensure the drying of dichloromethane, the dichloromethane needs to be further dried, and therefore, the first drying kettle 13 is provided with a second drying kettle 14 between the receiving tank 15.

[0029] In summary, the scheme has the following advantages: the tail gas containing dichloromethane is deeply condensed by the first condenser 1, the dichloromethane is converted from gaseous state to liquid state, then the liquid dichloromethane is refined by the oil-water separator 4 and the first drying kettle 13 to complete dehydration, and the recovery of dichloromethane is completed, which reduces the cost and reduces the environmental pollution caused by dichloromethane emission.

[0030] There are many other embodiments, and those skilled in the art can make various corresponding changes and modifications according to the present application without departing from the spirit and essence of the present application, but these corresponding changes and modifications should belong to the protection scope of the claims attached to the present application.

Claims

1. A methylene chloride refining apparatus characterized by comprising: It includes first condenser (1), oil-water separator (4), first drying kettle (13) and receiving tank (15), the oil-water separator (4) is located between first condenser (1) and first drying kettle (13), the first drying kettle (13) is located between receiving tank (15) and oil-water separator (4), the receiving tank (15) is also connected with delivery pump (16), the first condenser (1), oil-water separator (4), first drying kettle (13), receiving tank (15) are sequentially connected by pipeline.

2. The methylene chloride refining apparatus according to claim 1, characterized by Second condenser (2) is arranged between the first condenser (1) and the oil-water separator (4), and the second condenser (2) is connected by pipeline with the oil-water separator (4).

3. The methylene chloride refining apparatus according to claim 1, characterized by The oil-water separator (4) is also connected by pipeline with third condenser (3).

4. The methylene chloride refining apparatus according to claim 2, characterized by Alkaline washing tower (5) is arranged between the oil-water separator (4) and the first drying kettle (13), and the alkaline washing tower (5) is connected by pipeline with the oil-water separator (4) and the first drying kettle (13) respectively.

5. The methylene chloride refining apparatus according to claim 4, characterized by Water washing tower (6) is arranged between the alkaline washing tower (5) and the first drying kettle (13), and the water washing tower (6) is connected by pipeline with the alkaline washing tower (5) and the first drying kettle (13) respectively.

6. The methylene chloride refining apparatus according to claim 5, characterized by First rectifying tower (7) and first rotary plate condenser (8) are arranged between the water washing tower (6) and the first drying kettle (13), and the water washing tower (6), the first rectifying tower (7), the first rotary plate condenser (8) and the first drying kettle (13) are sequentially connected by pipeline.

7. The methylene chloride refining apparatus according to claim 6, characterized by The first rectifying tower (7) is also connected by pipeline with second rectifying tower (9), and the second rectifying tower (9) is also connected with ethylbenzene storage tank (12) and benzene receiving tank (11), and second rotary plate condenser (10) is arranged between the benzene receiving tank (11) and the second rectifying tower (9).

8. The methylene chloride refining apparatus according to claim 1, characterized by Second drying kettle (14) is arranged between the first drying kettle (13) and the receiving tank (15).

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