Reaction system for continuously preparing pentachloropropane and tetrachloropropane

Abstract

The utility model discloses a reaction system for continuously preparing pentachloropropane and tetrachloropropane, which comprises a reaction kettle, a heat exchanger, a static mixer and a Venturi ejector which are connected in sequence, the reaction kettle comprises a reaction kettle body, a stirring device, a magnetic attraction device and a cooling and heating device, wherein the stirring device, the magnetic attraction device and the cooling and heating device are respectively arranged on the reaction kettle body. According to the utility model, iron powder is skillfully fixed in the reaction kettle and is uniformly distributed, so that a larger contact area between liquid and solid phases is provided, the formation of a divalent iron complex is accelerated, and an effective catalyst is supplemented for a reaction system in time. A large amount of circulating liquid can quickly remove reaction heat, and after newly added carbon tetrachloride and auxiliaries are uniformly mixed, vinyl chloride or ethylene gas is uniformly dissolved in the circulating liquid through the venturi ejector, so that the vinyl chloride or the ethylene gas reacts quickly.

Description

Technical Field

[0001] This invention belongs to the field of reaction vessel technology, and specifically relates to a reaction system for the continuous preparation of pentachloropropane and tetrachloropropane. Background Technology

[0002] In methods for preparing pentachloropropane from carbon tetrachloride and vinyl chloride, and methods for preparing tetrachloropropane from carbon tetrachloride and ethylene using iron as the main catalyst, elemental iron needs to be converted to ferrous iron before being coupled to a phase transfer catalyst dissolved in the organic system to catalyze the reaction. This process is relatively slow, and the settling of iron powder further delays the conversion of elemental iron to its valence state. Therefore, a longer reaction time is required to ensure the conversion rate of vinyl chloride or ethylene. Simultaneously, reaction products such as R240fa or R250fb cannot be removed from the reactor in a timely manner, prolonging their further contact time with vinyl chloride or ethylene and leading to an increase in byproduct content. Furthermore, because iron powder accumulates at the bottom of the reactor, catalytically active complexes are first generated from the surface of the accumulated iron powder at the bottom. The complexes are difficult to distribute evenly within the reactor, which is another reason for the increase in byproducts. The slowed reaction rate is the main reason why this type of reaction is difficult to operate continuously. Utility Model Content

[0003] To address the deficiencies or shortcomings of the existing technology, this invention provides a reaction system for the continuous preparation of pentachloropropane and tetrachloropropane. This system uniformly adsorbs unreacted iron powder onto the inner wall of the reaction vessel or the surface of a built-in magnet. The magnet is uniformly installed on the outer wall of the inner liner of the reaction vessel or inside the vessel, increasing the contact area between the iron powder and the liquid. Under stirring, the complex formed on the surface of the iron powder can be uniformly distributed within the vessel.

[0004] The purpose of this application is achieved through the following technical solution:

[0005] A reaction system for the continuous preparation of pentachloropropane and tetrachloropropane includes a reaction vessel, a heat exchanger, a static mixer, and a Venturi injector, wherein the reaction vessel, heat exchanger, static mixer, and Venturi injector are connected in sequence; the reaction vessel includes a reaction vessel body, a stirring device, a magnetic attraction device, and a cooling and heating device, wherein the stirring device, the magnetic attraction device, and the cooling and heating device are respectively installed on the reaction vessel body.

[0006] Preferably, the device further includes an iron powder feeding device, which includes a buffer silo, a spiral powder conveyor, a dispensing silo, a pressure stabilizing silo, and a silo weighing device. The discharge end of the buffer silo is connected to the spiral powder conveyor, the discharge end of the spiral powder conveyor is connected to the dispensing silo, the discharge end of the spiral powder conveyor is connected to the pressure stabilizing silo, the discharge end of the pressure stabilizing silo is connected to the feed port of the reactor, and the silo weighing device is connected to the buffer silo.

[0007] Preferably, the stirring device includes a stirring motor, a reducer, a stirring shaft, and stirring paddles. The stirring motor and the reducer are installed on the top of the reactor body. The stirring motor is connected to the stirring shaft inside the reactor body through the reducer. Several stirring paddles are provided and installed on the stirring shaft.

[0008] Preferably, the magnetic attraction device includes an inner magnetic rod and an outer wall magnetic rod. The inner magnetic rods are installed at equal intervals on the inner side wall and bottom of the reactor body through magnetic rod fixing brackets, and the outer wall magnetic rods are installed on the outer wall of the reactor body corresponding to the inner magnetic rods.

[0009] Preferably, the cooling and heating device includes a jacket that covers the outside of the reactor body, forming a cooling and heating space between the jacket and the reactor body. The upper part of the cooling and heating space is provided with a cooling water outlet and a steam inlet, and the bottom part of the cooling and heating space is provided with a cooling water inlet and a condensate outlet.

[0010] Preferably, the outlet of the reactor is connected to the tube-side inlet of the heat exchanger via a circulating pump, the tube-side outlet of the heat exchanger is connected to the inlet of the static mixer, the outlet of the static mixer is connected to the liquid inlet of the Venturi ejector, the outlet of the Venturi ejector is connected to the circulating feed inlet of the reactor, a check valve is installed at the tube-side outlet of the heat exchanger, another outlet of the heat exchanger tube-side is connected to a material collection pipeline, the inlet of the static mixer is connected to a mixed liquid pipeline, and the gas phase inlet of the Venturi ejector is connected to the ethylene feed pipeline.

[0011] Preferably, a reactor weighing device is installed on the reactor body.

[0012] Preferably, the discharge ends of the spiral powder conveyor, the dispensing silo, and the pressure stabilizing silo are each equipped with a shut-off valve.

[0013] Preferably, flow meters and control valves are respectively installed on the extracted material pipeline, the mixed liquid pipeline and the ethylene feed pipeline.

[0014] This invention provides a reaction system for the continuous preparation of pentachloropropane and tetrachloropropane. The system circulates a large amount of mother liquor. Fresh carbon tetrachloride and additives are uniformly mixed with the circulating mother liquor in a static mixing zone, and then enter a Venturi injector. Gas-phase vinyl chloride or ethylene is drawn into the circulating liquid through the Venturi, ensuring that the gas-phase vinyl chloride or ethylene is uniformly dissolved in the circulating liquid. This reduces the generation of byproducts and accelerates the reaction. The large amount of circulating liquid allows for rapid removal of reaction heat, resulting in a more moderate reaction temperature.

[0015] Compared with the prior art, this application has at least the following obvious advantages and effects:

[0016] This invention ingeniously fixes iron powder within the reaction vessel and distributes it evenly, providing a larger contact area between the liquid and solid phases, accelerating the formation of ferrous complexes, and promptly replenishing the reaction system with an effective catalyst. A large amount of circulating liquid can quickly remove the heat of reaction, and after the newly added carbon tetrachloride and additives are evenly mixed, vinyl chloride or ethylene gas is uniformly dissolved in the circulating liquid through a Venturi injector, enabling a rapid reaction. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0018] Figure 2 This is a schematic diagram of the structure of the reaction vessel in this utility model;

[0019] Figure 3 This is a schematic diagram of the iron powder feeding device in this utility model;

[0020] Figure 4 This is a plan view showing the distribution of the magnetic attraction device inside the reactor in this utility model;

[0021] List of components in this application:

[0022] 1. Reactor; 2. Heat exchanger; 3. Static mixer; 4. Venturi injector; 5. Iron powder feeding device; 6. Circulating pump; 7. Check valve; 8. Flow meter; 9. Control valve; 11. Reactor body; 12. Stirring device; 13. Magnetic suction device; 14. Cooling and heating device; 15. Reactor weighing device; 21. Outgoing material pipeline; 31. Mixed liquid pipeline; 41. Ethylene feed pipeline; 51. Buffer silo; 52. Dispensing silo; 5 3. Spiral powder conveyor; 54. Pressure stabilizing silo; 55. Silo weigher; 56. Shut-off valve; 121. Agitator motor; 122. Reducer; 123. Agitator shaft; 124. Agitator paddle; 131. Inner magnetic rod; 132. Outer wall magnetic rod; 133. Magnetic rod fixing bracket; 141. Jacket; 142. Cooling and heating space; 143. Cooling water outlet; 144. Steam inlet; 145. Cooling water inlet; 146. Condensate outlet. Detailed Implementation

[0023] Specific embodiments of this application are described in conjunction with the accompanying drawings and the following description to teach those skilled in the art how to make and use this application. For the purpose of teaching the principles of the application, some conventional aspects have been simplified or omitted. Those skilled in the art should understand that variations derived from these embodiments fall within the scope of this application. Those skilled in the art should understand that the following features can be combined in various ways to form multiple variations of this application. Terms such as “upper,” “lower,” “left,” “right,” “middle,” and “one” used in this application are merely for clarity of description and are not intended to limit the scope of implementation of this utility model. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of implementation of this utility model. Therefore, this application is not limited to the specific embodiments described below, but is only defined by the claims and their equivalents.

[0024] Example 1

[0025] like Figure 1 As shown, this embodiment relates to a reaction system for the continuous preparation of pentachloropropane and tetrachloropropane, which includes a reaction vessel 1, a heat exchanger 2, a static mixer 3, and a Venturi injector 4, wherein the reaction vessel 1, the heat exchanger 2, the static mixer 3, and the Venturi injector 4 are connected in sequence; the reaction vessel 1 includes a reaction vessel body 11, a stirring device 12, a magnetic suction device 13, and a cooling and heating device 14, which are respectively installed on the reaction vessel body 11; the reaction vessel body 11 is also equipped with a reaction vessel weighing device 15 for measuring the liquid holding capacity inside the reaction vessel body 11.

[0026] Specifically, such as Figure 1 and Figure 2 As shown, the stirring device 12 includes a stirring motor 121, a reducer 122, a stirring shaft 123, and a stirring paddle 124. The stirring motor 121 and the reducer 122 are installed on the top of the reactor body 11. The stirring motor 121 is connected to the stirring shaft 123 inside the reactor body 11 through the reducer 122. Several stirring paddles 124 are provided and installed on the stirring shaft 123.

[0027] The magnetic attraction device 13 includes an inner magnetic rod 131 and an outer wall magnetic rod 132. The inner magnetic rods 131 are installed at equal intervals on the inner wall and bottom of the reactor body 11 via magnetic rod fixing brackets 123. The outer wall magnetic rods 132 are installed on the outer wall of the reactor body 11 corresponding to the inner magnetic rods 131. The magnetic attraction device 13 is used to attract unreacted iron powder to the surface of the inner magnetic rods 131 or the inner wall of the reactor body 11.

[0028] The cooling and heating device 14 includes a jacket 141 that covers the outside of the reactor body 11, forming a cooling and heating space 142 between the jacket 141 and the reactor body 11. The upper part of the cooling and heating space 142 is provided with a cooling water outlet 143 and a steam inlet 144, while the bottom of the cooling and heating space 142 is provided with a cooling water inlet 145 and a condensate outlet 146. The cooling and heating device has both heating and cooling functions. When the temperature rises from room temperature to the reaction temperature, the heating function is activated. During the reaction, the overall temperature of the reaction system is controlled to remain stable based on the reactor temperature, heat exchanger outlet temperature, and the amount of cooling medium used.

[0029] like Figure 3 As shown, in this embodiment of the application, an iron powder feeding device 5 is also included. The iron powder feeding device 5 includes a buffer silo 51, a spiral powder conveyor 52, a dispensing silo 53, a pressure stabilizing silo 54, and a silo weighing device 55. The discharge end of the buffer silo 51 is connected to the spiral powder conveyor 52, the discharge end of the spiral powder conveyor 52 is connected to the dispensing silo 53, the discharge end of the dispensing silo 53 is connected to the pressure stabilizing silo 54, and the discharge end of the pressure stabilizing silo 54 is connected to the feeding port of the reactor 1. The silo weighing device 55 is connected to the buffer silo 51. A shut-off valve 56 is respectively installed at the discharge ends of the spiral powder conveyor 52, the dispensing silo 53, and the pressure stabilizing silo 51.

[0030] like Figure 1 As shown in the embodiment of this application, the outlet of the reactor 1 is connected to the tube-side inlet of the heat exchanger 2 via a circulating pump 6, the tube-side outlet of the heat exchanger 2 is connected to the inlet of the static mixer 3, the outlet of the static mixer 3 is connected to the liquid inlet of the Venturi ejector 4, the outlet of the Venturi ejector 4 is connected to the circulating feed inlet of the reactor 1, a check valve 7 is installed at the tube-side outlet of the heat exchanger 2, another outlet of the tube-side of the heat exchanger 2 is connected to a material collection pipeline 21, and the inlet of the static mixer 3 is connected to a mixed liquid pipeline 31 for replenishing fresh carbon tetrachloride and additives; the additives can be pre-mixed with carbon tetrachloride. After uniform feeding, the raw materials are fed together according to the specified ratio. The gas phase inlet of the Venturi injector 4 is connected to the ethylene feed pipeline 41 for the feeding of vinyl chloride or ethylene gas. The output material pipeline 21, the mixed liquid pipeline 31 and the ethylene feed pipeline 41 are respectively equipped with flow meters 8 and control valves 9. In this application, the heat exchanger 2 can meet the heating needs when the system starts up and the cooling needs when the reaction is in progress. Various heating (such as steam, heat transfer oil, etc.) and cooling media (circulating water, etc.) can be selected. By controlling the amount of material entering and leaving the system, combined with the weighing indication of the reactor 1, the overall material balance of the reaction system is maintained.

[0031] The principle of this utility model:

[0032] CCl4 + CH2 = CH l(Ethylene chloride) → CCl3CH2CHCl2 (R240fa, i.e., pentachloropropane)

[0033] CCl4 + CH2 = CH2 (ethylene) → CCl3CH2CH2Cl (R250fb, i.e., tetrachloropropane)

[0034] If TBP is selected as the catalytic agent, then the substance responsible for its catalytic action is the FeCl2-TBP complex.

[0035] CCl4+FeCl2-TBP→·CCl3-FeCl3-TBP

[0036] ·CCl3-FeCl3-TBP+CH2=CH l / CH2=CH2→

[0037] CCl3CH2CHCl2 / CCl3CH2CH2Cl+FeCl2-TBP

[0038] The system is rich in chlorine. In actual production, it is difficult for FeCl3-TBP to supply Cl and reduce itself to FeCl2-TBP to maintain its activity. Therefore, Fe is added to convert FeCl3-TBP to FeCl2-TBP. This conversion rate is the key step that limits the reaction rate.

[0039] A certain amount of carbon tetrachloride and additives are added to the reactor, and stirring is started. A certain amount of iron powder is then added, which adheres to the inner wall of the reactor and the surface of the built-in magnetic rod. The circulation pump is then activated, and a large amount of liquid is injected into the reactor through external circulation. Compared to the liquid settling to the bottom, this invention provides a larger contact area between the iron powder and the liquid. Furthermore, the external circulation of a large amount of liquid reduces the radial material concentration difference within the reactor, allowing the complex reduced on the iron powder surface to be evenly distributed throughout the system. Additionally, the added carbon tetrachloride and additives are uniformly mixed with the large amount of circulating liquid through a static mixer. Then, gaseous vinyl chloride or ethylene is drawn in through a Venturi injector and dissolved in the liquid, resulting in a more uniform mixture than liquid feeding or gas bubbling methods.

[0040] By improving the timely reduction and uniform distribution of the catalytic complex, the mixing of vinyl chloride or ethylene in the liquid is made more uniform, and the circulation pipeline is used to ensure that the two reactants are mixed uniformly and in preferential contact, thereby improving selectivity and conversion efficiency.

[0041] By assessing the system's reactivity, the feed rate is controlled, and the output rate is controlled by the reactor's liquid holdup.

[0042] The system temperature is interlocked and controlled through the heat exchanger and reactor jacket to maintain the optimal reaction temperature.

[0043] Example 2

[0044] like Figure 1 As shown, taking the continuous preparation of pentachloropropane as an example, a certain amount of carbon tetrachloride and an auxiliary agent (such as TBP) are first added to the reactor. Stirring is started, and a certain amount of iron powder is added. The iron powder will not participate in the reaction quickly, but will be adsorbed on the inner wall of the reactor body and the outer wall of the magnetic rod inside the reactor. The circulation pump is started, and the jacket is turned on to raise the temperature to the target reaction temperature. The system will slowly produce FeCl2-TBP complex. It can also be initiated by adding FeCl3 to accelerate the formation of FeCl2-TBP complex.

[0045] Vinyl chloride gas is initially introduced into the system. The presence and rate of reaction are determined by monitoring system pressure and temperature changes. Once the reaction begins, the temperature is stabilized using one or a combination of the heat exchanger and reactor jacket. Under stable temperature conditions, the rate of vinyl chloride feed is adjusted based on system pressure. When the system concentration reaches the target level, carbon tetrachloride and additives are continuously fed, along with iron powder. A specific feed ratio of vinyl chloride, carbon tetrachloride, additives, and iron powder is maintained. If the reaction proceeds normally, the outlet regulating valve is opened to maintain a stable liquid holdup in the reactor. The continuous production of pentachloropropane then commences.

[0046] Example 3

[0047] like Figure 1 As shown, taking the continuous preparation of tetrachloropropane as an example, a certain amount of carbon tetrachloride and an auxiliary agent (such as TBP) are first added to the reactor. Stirring is started, and a certain amount of iron powder is added. The iron powder will not participate in the reaction quickly, but will be adsorbed on the inner wall of the reactor and the outer wall of the magnetic rod inside the reactor. The circulation pump is started, and the jacket is turned on to raise the temperature to the target reaction temperature. The system will slowly produce FeCl2-TBP complex. It can also be initiated by adding FeCl3 to accelerate the formation of FeCl2-TBP complex.

[0048] Ethylene gas is initially introduced into the system. The presence and rate of reaction are determined based on system pressure and temperature changes. Once the reaction begins, the temperature is stabilized using one or a combination of the heat exchanger and reactor jacket. Under stable temperature conditions, the ethylene feed rate is adjusted according to system pressure. When the system material concentration reaches the target, carbon tetrachloride and additives are continuously fed, along with iron powder. A specific feed ratio of ethylene, carbon tetrachloride, additives, and iron powder is maintained. If the reaction proceeds normally, the outlet regulating valve is opened to maintain a stable liquid holdup in the reactor. The continuous production of tetrachloropropane then commences.

[0049] As those skilled in the art will readily conceive, any modifications, equivalent substitutions, improvements, etc., made using the concept and principles of this application should be included within the scope of the claims of this application.

Claims

1. A reaction system for the continuous preparation of pentachloropropane and tetrachloropropane, characterized in that, It includes a reaction vessel, a heat exchanger, a static mixer, and a Venturi injector, which are connected in sequence. The reaction vessel includes a reaction vessel body, a stirring device, a magnetic attraction device, and a cooling and heating device, which are respectively installed on the reaction vessel body.

2. The reaction system for the continuous preparation of pentachloropropane and tetrachloropropane according to claim 1, characterized in that, It also includes an iron powder feeding device, which comprises a buffer silo, a spiral powder conveyor, a dispensing silo, a pressure stabilizing silo, and a silo weighing device. The discharge end of the buffer silo is connected to the spiral powder conveyor, the discharge end of the spiral powder conveyor is connected to the dispensing silo, the discharge end of the dispensing silo is connected to the pressure stabilizing silo, the discharge end of the pressure stabilizing silo is connected to the feed port of the reactor, and the silo weighing device is connected to the buffer silo.

3. The reaction system for the continuous preparation of pentachloropropane and tetrachloropropane according to claim 1, characterized in that, The stirring device includes a stirring motor, a speed reducer, a stirring shaft, and stirring paddles. The stirring motor and speed reducer are installed on the top of the reactor body. The stirring motor is connected to the stirring shaft inside the reactor body through the speed reducer. Several stirring paddles are provided and installed on the stirring shaft.

4. The reaction system for the continuous preparation of pentachloropropane and tetrachloropropane according to claim 1, characterized in that, The magnetic attraction device includes an inner magnetic rod and an outer wall magnetic rod. The inner magnetic rods are installed at equal intervals on the inner side wall and bottom of the reactor body through magnetic rod fixing brackets, and the outer wall magnetic rods are installed on the outer wall of the reactor body corresponding to the inner magnetic rods.

5. The reaction system for the continuous preparation of pentachloropropane and tetrachloropropane according to claim 1, characterized in that, The cooling and heating device includes a jacket that covers the outside of the reactor body, forming a cooling and heating space between the jacket and the reactor body. The upper part of the cooling and heating space is provided with a cooling water outlet and a steam inlet, and the bottom part of the cooling and heating space is provided with a cooling water inlet and a condensate outlet.

6. The reaction system for the continuous preparation of pentachloropropane and tetrachloropropane according to claim 1, characterized in that, The outlet of the reactor is connected to the tube-side inlet of the heat exchanger via a circulating pump. The tube-side outlet of the heat exchanger is connected to the inlet of the static mixer. The outlet of the static mixer is connected to the liquid inlet of the Venturi ejector. The outlet of the Venturi ejector is connected to the circulating feed inlet of the reactor. A check valve is installed at the tube-side outlet of the heat exchanger. The other outlet of the heat exchanger tube-side is connected to a material collection pipeline. The inlet of the static mixer is connected to a mixed liquid pipeline. The gas phase inlet of the Venturi ejector is connected to the ethylene feed pipeline.

7. The reaction system for the continuous preparation of pentachloropropane and tetrachloropropane according to claim 1, characterized in that, A reactor weighing device is installed on the reactor body.

8. The reaction system for the continuous preparation of pentachloropropane and tetrachloropropane according to claim 2, characterized in that, The discharge ends of the spiral powder conveyor, the dispensing silo, and the pressure stabilizing silo are each equipped with a shut-off valve.

9. The reaction system for the continuous preparation of pentachloropropane and tetrachloropropane according to claim 6, characterized in that, Flow meters and control valves are respectively installed on the extracted material pipeline, the mixed liquid pipeline and the ethylene feed pipeline.

Images