A continuous production process and production device for high-purity carbon tetrachloride

Abstract

The present invention discloses a continuous production process of high-purity carbon tetrachloride, wherein a high-purity carbon tetrachloride product is obtained and enters a material collection tank (4). The present invention also discloses a device for continuous production of high-purity carbon tetrachloride, which is characterized in that it comprises a distillation tower (1), an alkali washing separation tank (2) and an azeotropic tower (3), wherein a feed port (6) and a discharge port (7) are respectively arranged on the side of the distillation tower (1), a raw material barrel (8) is connected to the feed port (6) through a feed pipe (9), a DCS regulating system (5) is arranged on the feed pipe (9), the discharge port (7) of the distillation tower (1) is connected to the inlet of the alkali washing separation tank (2) through a discharge pipe (10), a heat exchanger IV (18) is arranged on the discharge pipe (10), the outlet of the alkali washing separation tank (2) is connected to the input port on the side of the azeotropic tower (3), and the output port at the bottom of the azeotropic tower (3) is connected to the material collection tank (4).

Description

[0001] The present application relates to a continuous production process of high-purity carbon tetrachloride and a production device thereof. Background Art

[0002] At present, the by-product carbon tetrachloride of the methane chloride unit can be obtained by the following method: the crude carbon tetrachloride is treated in a distillation tower, and the main content of carbon tetrachloride does not exceed 99.5% after removing high-boiling substances such as trichloroethylene and tetrachloroethylene. After alkali washing and azeotropic treatment, it cannot meet the high purity requirements. The standard purity of carbon tetrachloride is above 99.8%, while the current existing purity is only 99.4%. The main content of carbon tetrachloride obtained by general refining methods cannot meet the market requirement of more than 99.8% main content, because the several thousand PPM of 1,2-dichloroethane contained in the crude carbon tetrachloride forms an azeotrope with carbon tetrachloride in the distillation tower. In the distillation tower, 1,2-dichloroethane changes from a heavy component to a light component, and is enriched in the top product, which reduces the main content and the grade of carbon tetrachloride products, and does not meet the market quality requirements. Summary of the invention

[0003] The present application provides a continuous production process of high-purity carbon tetrachloride and a production device thereof, which can not only obtain high-purity carbon tetrachloride, but also has a reliable preparation method, a convenient and fast preparation device and a simple structure.

[0004] The present application adopts the following technical scheme: a device for continuous production of high-purity carbon tetrachloride, which includes a distillation tower, an alkali washing separation tank and an azeotropic tower, wherein a feed port and a discharge port are respectively arranged on the side of the distillation tower, the raw material barrel is connected to the feed port through a feed pipe, a DCS regulating system is arranged on the feed pipe, the discharge port of the distillation tower is connected to the inlet of the alkali washing separation tank through a discharge pipe, a heat exchanger IV is arranged on the discharge pipe, the outlet of the alkali washing separation tank is connected to the input port on the side of the azeotropic tower, the output port at the bottom of the azeotropic tower is connected to the material collecting tank, the bottom of the distillation tower is connected to the side of the distillation tower through a centrifugal pump I and a heat exchanger I in sequence, the top of the distillation tower is connected to the side of the distillation tower through a heat exchanger II, a collecting tank and a centrifugal pump II in sequence, a centrifugal pump III is arranged between the outlet of the alkali washing separation tank and the input port on the side of the azeotropic tower, the A heat exchanger III is connected in series between the bottom of the azeotropic tower and the side of the azeotropic tower. The process of continuously producing high-purity carbon tetrachloride using the device is as follows: the crude carbon tetrachloride flow rate is 1.3-1.5m3 / h, and is continuously fed into the carbon tetrachloride distillation tower, and then heated by steam. The temperature of the top of the distillation tower is controlled at 76.5-77°C, the pressure of the top of the distillation tower is controlled at 0.005-0.007Mpa, and the reflux ratio of the top of the distillation tower is controlled at 5.5-6. When the concentration of 1,2-dichloroethane in the top component reaches a certain level, the material is discharged intermittently to ensure the distribution concentration of 1,2-dichloroethane in the distillation tower. After the component analysis of the tower side discharge is qualified and the carbon tetrachloride content is greater than 99.8%, the material is continuously discharged and sequentially enters the alkali washing separation tank and the azeotropic tower for treatment to obtain a high-purity carbon tetrachloride product and enters the material collection tank. The crude carbon tetrachloride is regulated by the DCS regulation system.

[0005] The present application has the following beneficial effects: after adopting the above technical scheme, the impurities 1,2-dichloroethane in the crude carbon tetrachloride of the present application form azeotropes with carbon tetrachloride during the distillation process, and 1,2-dichloroethane is enriched at the top of the tower from heavy components to light components, which seriously affects the main content of carbon tetrachloride. According to the principle that the azeotropes of 1,2-dichloroethane and carbon tetrachloride are distributed differently in the distillation tower, a suitable discharging position is selected instead of the top of the tower, and the high-purity carbon tetrachloride enters the alkali washing azeotropic system for treatment through the continuous discharging of the tower bottom to obtain a high-purity carbon tetrachloride product. The present application is designed for the fact that 1,2-dichloroethane in the crude carbon tetrachloride can form azeotropes with carbon tetrachloride, which is difficult to remove in normal process treatment, affects the main content of carbon tetrachloride, and thus affects the product grade. Through the tower side discharging, impurities of different properties are removed to obtain high-purity carbon tetrachloride. The preparation device adopted in the present application is convenient and fast, simple in structure, and has high preparation efficiency, which effectively reduces the preparation cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 This is a schematic diagram of the structure of this application. DETAILED DESCRIPTION

[0007] The present application discloses a continuous production process of high-purity carbon tetrachloride, which continuously feeds crude carbon tetrachloride into a carbon tetrachloride distillation tower 1 at a flow rate of 1.3-1.5 m3 / h, then heats the distillation tower 1 by steam, controls the temperature of the top of the distillation tower 1 to be 76.5-77°C, controls the pressure of the top of the distillation tower 1 to be 0.005-0.007 MPa, controls the reflux ratio of the top of the distillation tower 1 to be 5.5-6, and discharges materials at intervals when the concentration of 1,2-dichloroethane in the top components reaches a certain level, thereby ensuring the distribution concentration of 1,2-dichloroethane in the distillation tower 1. After the components of the tower side discharge are analyzed to be qualified and the carbon tetrachloride content is greater than 99.8%, the materials are continuously discharged and sequentially enter an alkali washing separation tank 2 and an azeotropic tower 3 for treatment, so as to obtain a high-purity carbon tetrachloride product and enter a material collecting tank 4, and the crude carbon tetrachloride is regulated and controlled by a DCS regulating system 5 for flow rate.

[0008] Finally, the product in the material collection tank 4 is analyzed. The product analysis data is shown in Table 1 Table 1

[0009]

[0010] According to the order of peak elution time, the six peaks correspond to chloroform, carbon tetrachloride, 1-2-dichloroethane, trichloroethylene, bromodichloromethane and bromotrichloromethane.

[0011] exist Figure 1 The present application discloses a device for continuous production of high-purity carbon tetrachloride, which comprises a distillation tower 1, an alkali washing separation tank 2 and an azeotropic tower 3, wherein a feed port 6 and a discharge port 7 are respectively arranged on the side of the distillation tower 1, a raw material barrel 8 is connected to the feed port 6 through a feed pipe 9, a DCS regulating system 5 is arranged on the feed pipe 9, the discharge port 7 of the distillation tower 1 is connected to the inlet of the alkali washing separation tank 2 through a discharge pipe 10, a heat exchanger IV18 is arranged on the discharge pipe 10, and the outlet of the alkali washing separation tank 2 is connected to the inlet of the azeotropic tower 3. The inlet port is connected, the output port at the bottom of the azeotropic tower 3 is connected to the material collecting tank 4, the bottom of the distillation tower 1 is connected to the side of the distillation tower 1 through a centrifugal pump I11 and a heat exchanger I12 in sequence, the top of the distillation tower 1 is connected to the side of the distillation tower 1 through a heat exchanger II13, a collecting tank 14 and a centrifugal pump II15 in sequence, a centrifugal pump III16 is provided between the outlet of the alkali washing separation tank 2 and the input port on the side of the azeotropic tower 3, and a heat exchanger III17 is connected in series between the bottom of the azeotropic tower 3 and the side of the azeotropic tower 3.

Claims

1. A device for continuous production of high-purity carbon tetrachloride, characterized in that It comprises a distillation tower (1), an alkali washing separation tank (2) and an azeotropic tower (3). A feed port (6) and a discharge port (7) are respectively arranged on the side of the distillation tower (1). A raw material barrel (8) is connected to the feed port (6) via a feed pipe (9). A DCS regulating system (5) is arranged on the feed pipe (9). The discharge port (7) of the distillation tower (1) is connected to the inlet of the alkali washing separation tank (2) via a discharge pipe (10). A heat exchanger IV (18) is arranged on the discharge pipe (10). The alkali washing separation tank (2 ) is connected to the input port on the side of the azeotropic tower (3), the output port at the bottom of the azeotropic tower (3) is connected to the material collecting tank (4), the bottom of the distillation tower (1) is connected to the side of the distillation tower (1) via a centrifugal pump I (11) and a heat exchanger I (12) in sequence, the top of the distillation tower (1) is connected to the side of the distillation tower (1) via a heat exchanger II (13), a collecting tank (14) and a centrifugal pump II (15) in sequence, the outlet of the alkali washing separation tank (2 ... A centrifugal pump III (16) is provided between the ports, and a heat exchanger III (17) is connected in series between the bottom of the azeotropic tower (3) and the side of the azeotropic tower (3). The process of continuously producing high-purity carbon tetrachloride using the device is as follows: the crude carbon tetrachloride flow rate is 1.3-1.5 m3 / h, and is continuously fed into the carbon tetrachloride distillation tower (1), and then heated by steam, the temperature of the top of the distillation tower (1) is controlled at 76.5-77°C, the pressure of the top of the distillation tower (1) is controlled at 0.005-0.007 MPa, and the distillation tower (1) is heated by steam. The reflux ratio of the top of the distillation tower (1) is controlled at 5.5 to 6. When the 1,2-dichloroethane in the top components reaches a certain concentration, the material is discharged intermittently to ensure the distribution concentration of 1,2-dichloroethane in the distillation tower (1). The side discharge component is analyzed to be qualified. After the carbon tetrachloride content is greater than 99.8%, the material is continuously discharged and sequentially enters the alkali washing separation tank (2) and the azeotropic tower (3) for treatment to obtain a high-purity carbon tetrachloride product that enters the material collection tank (4). The crude carbon tetrachloride is regulated by the DCS regulation system (5) to adjust the flow rate.

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