A treatment system and method for waste antimony pentachloride catalyst

Abstract

The present invention relates to the technical field of waste catalyst recovery, and specifically to a treatment system and method for waste antimony pentachloride catalyst. The treatment system comprises a hydrolysis device, a centrifugal device, and a drying device; the hydrolysis device is provided with a stirring device, and the top is provided with a waste catalyst inlet, an alkali liquid inlet, an oxidant inlet, and a water inlet, the side wall is provided with a clear liquid outlet, and the bottom is provided with a slurry outlet; the slurry outlet of the hydrolysis device is connected to the inlet of the centrifugal device; the solid phase outlet of the centrifugal device is connected to the inlet of the drying device. The treatment system has a simple process flow, reduces the energy consumption cost of the current waste catalyst treatment, and the hydrolysis reaction is carried out under alkaline conditions, and the material of the hydrolysis kettle does not need to be acid-resistant, which greatly reduces the equipment investment. At the same time, it has the advantages of airtightness, safety, and high degree of automation. Wastewater and waste gas are strictly treated and discharged up to the standard, and can be widely used in the production of difluoromonochloromethane.

Description

Technical Field

[0001] The invention relates to the technical field of waste catalyst recovery, and in particular to a treatment system and a treatment method for waste antimony pentachloride catalyst. Background Art

[0002] The activity of antimony pentachloride, a catalyst used in the production of difluorochloromethane, will gradually decrease after a period of reaction until part of the catalyst loses its activity and turns into antimony pentafluoride. Therefore, part of the catalyst in the reactor needs to be replaced after a period of time.

[0003] Waste antimony pentachloride catalyst contains organic high-boiling substances such as chloroform, antimony pentachloride, antimony trichloride, antimony pentafluoride, etc., which are highly hazardous substances and will produce a large amount of toxic and harmful gases during the hydrolysis process. The existing treatment methods have long process flows, high energy consumption, and great difficulty in separation, and cannot meet the society's increasingly high requirements for automation, safety, environmental protection, and energy conservation in chemical and environmental protection equipment. Summary of the invention

[0004] In view of the above problems, the present invention provides a system and method for treating waste antimony pentachloride catalyst in the production process of difluoromonochloromethane.

[0005] Specifically, the present invention provides the following technical solutions:

[0006] A system for treating a waste antimony pentachloride catalyst, comprising a hydrolysis device, a centrifugal device, and a drying device;

[0007] The hydrolysis device is provided with a stirring device, a waste catalyst inlet, an alkali solution inlet, an oxidant inlet and a water inlet are provided on the top, a clear liquid outlet is provided on the side wall, and a slurry outlet is provided on the bottom;

[0008] The slurry outlet of the hydrolysis device is connected to the inlet of the centrifugal device;

[0009] The solid phase outlet of the centrifugal device is connected to the inlet of the drying device.

[0010] Preferably, in the above-mentioned treatment system, the hydrolysis device is also provided with an exhaust port, and the exhaust port of the hydrolysis device is connected to a water alkali washing system, and the water alkali washing system is used for water alkali washing to treat and collect acidic gases.

[0011] Preferably, in the above-mentioned treatment system, the clear liquid outlet of the hydrolysis device is connected to the spent alkali tank.

[0012] Preferably, in the above-mentioned treatment system, the centrifugal device is a horizontal scraper discharge centrifuge, and the drying device is a double cone rotary vacuum dryer. After hydrolysis, the horizontal scraper discharge centrifuge and the double cone rotary vacuum dryer are used for post-treatment. The whole system is not easy to be blocked (sodium fluoride and sodium chloride are easy to crystallize) and has high drying efficiency.

[0013] Preferably, the above-mentioned processing system further comprises a plasma cracking device, and the liquid phase outlet of the centrifugal device is connected to the plasma cracking device.

[0014] Preferably, in the above-mentioned processing system, the drying device is provided with an exhaust port, and the exhaust port of the drying device is connected to the plasma cracking device.

[0015] The present invention also provides a method for treating a waste antimony pentachloride catalyst, comprising the following steps:

[0016] (1) adding industrial water to a hydrolysis device, and further adding sodium hydroxide solution to adjust the pH value to above 10;

[0017] (2) adding the waste antimony pentachloride catalyst and hydrogen peroxide to the hydrolysis device respectively and continuously, maintaining a certain temperature and stirring speed for hydrolysis reaction, and the acidic gas generated in the reaction enters the water alkali washing system for water alkali washing treatment;

[0018] (3) The feed liquid after the hydrolysis reaction is allowed to stand to separate the clear liquid and the slurry. The clear liquid enters the waste alkali tank, the slurry enters the centrifuge for solid-liquid separation, the separated liquid phase enters the plasma cracking device, and the separated solid phase enters the dryer for drying;

[0019] During the hydrolysis reaction, the pH value of the reaction system is maintained above 10 by adding sodium hydroxide solution.

[0020] Preferably, in the above treatment method, the temperature of the hydrolysis reaction is 50-60°C.

[0021] Preferably, in the above treatment method, the mass ratio of the total amount of the waste antimony pentachloride catalyst added to the industrial water is 1 to 5:10;

[0022] and / or, the Sb in the waste antimony pentachloride catalyst added continuously 3+ The molar flow ratio of the hydrogen peroxide is 1.8 to 2.2:3, preferably 2:3.

[0023] The beneficial effects achieved by the present invention are:

[0024] The treatment system of the waste antimony pentachloride catalyst provided by the present invention has a simple process flow, reduces the energy consumption cost of the current waste catalyst treatment, and performs a hydrolysis reaction under alkaline conditions, and the material of the hydrolysis kettle does not need to be acid-resistant, which greatly reduces equipment investment, thereby improving the economic and environmental benefits of the enterprise. At the same time, it has the advantages of airtightness, safety, and high degree of automation. Wastewater and waste gas are strictly treated and discharged in compliance with standards, and can be widely used in the production of difluoromonochloromethane. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the device described in Example 1; wherein, 1. hydrolysis kettle, 2. horizontal scraper unloading centrifuge, 3. double cone rotary vacuum dryer, 4. water alkali washing system, 5. waste alkali tank, 6. fluorine-containing wastewater treatment device, 7. plasma cracking device. DETAILED DESCRIPTION

[0026] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the art or the product instructions are used.

[0027] In the description of the present invention, unless otherwise specified, the terms "upper", "lower", etc. indicating the orientation or state relationship are based on the orientation or state relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0028] In the following examples, the instruments used without indicating the manufacturer are all conventional products that can be purchased through regular channels. The methods described are conventional methods unless otherwise specified, and the raw materials described can be obtained from public commercial channels unless otherwise specified.

[0029] In the following examples, the waste antimony pentachloride used comes from the F22 reactor, with about 30% waste antimony pentachloride (the proportion of Sb3+ in the waste antimony pentachloride is about 20%), 60% chloroform, 1% hydrogen chloride, 4% hydrogen fluoride, and the rest being F21, etc.

[0030] Example 1

[0031] like Figure 1 As shown, Example 1 provides a treatment system for waste antimony pentachloride catalyst in the production process of difluoromonochloromethane, comprising a hydrolysis kettle 1, a horizontal scraper unloading centrifuge 2, a double cone rotary vacuum dryer 3, a water alkali washing system 4, a waste alkali tank 5, a fluorine-containing wastewater treatment device 6, and a plasma cracking device 7;

[0032] The hydrolysis kettle 1 is provided with a stirring device, and the top thereof is provided with an inlet for the spent antimony pentachloride catalyst, an inlet for the sodium hydroxide solution, an inlet for the hydrogen peroxide solution and an inlet for the industrial water, a side wall is provided with a clear liquid outlet, and a bottom is provided with a slurry outlet;

[0033] The hydrolysis kettle 1 is also provided with an exhaust port, and the exhaust port of the hydrolysis kettle 1 is connected to the water alkali washing system 4;

[0034] The clear liquid outlet of the hydrolysis kettle 1 is connected to the spent alkali tank 5 and the fluorine-containing wastewater treatment device 6 in sequence;

[0035] The slurry outlet of the hydrolysis kettle 1 is connected to the inlet of the horizontal scraper discharge centrifuge 2;

[0036] The horizontal scraper discharge centrifuge 2 is provided with a solid phase outlet and a liquid phase outlet, wherein the solid phase outlet is connected to the double cone rotary vacuum dryer 3, and the liquid phase outlet is connected to the plasma cracking device 7;

[0037] The double-cone rotary vacuum dryer 3 is provided with an exhaust port, which is connected to the plasma cracking device 7 .

[0038] Example 2

[0039] The method for treating the waste antimony pentachloride catalyst using the treatment system described in Example 1 is specifically as follows:

[0040] In the hydrolysis kettle 1 (carbon steel, V = 5m 3 ) was added with 2000 kg of industrial water, stirred at 15 r / min, about 400 kg of 15% sodium hydroxide aqueous solution was prepared and added to the hydrolysis kettle 1, and the cooling circulating water in the side wall jacket of the hydrolysis kettle 1 was turned on. 600 kg of waste antimony pentachloride catalyst was slowly added to the hydrolysis kettle at a rate of 300 kg / h through the potential difference, while adding the waste antimony pentachloride catalyst at a rate of 1 m 3 / h rate of hydrogen peroxide, and automatically monitor the pH value, if the pH value drops to 10, automatically add 0.1m 3 15% sodium hydroxide aqueous solution is added to keep the solution in the hydrolysis kettle alkaline. After the addition is completed, the stirring is turned off and the solution is cooled to room temperature. The acidic gases such as HF and HCl generated during the hydrolysis process enter the water alkali washing system 4 for treatment and then meet the discharge standards.

[0041] The upper inorganic clear liquid in the hydrolysis kettle 1 is discharged into the waste alkali tank 5, and then transported to the fluorine-containing wastewater treatment device 6 through a pump; the remaining slurry, organic phase and a small amount of inorganic phase enter the horizontal scraper unloading centrifuge 2, and the slurry is separated at a speed of 3500-5000r / min, and the organic phase and a small amount of inorganic phase are transported to the plasma cracking device 7 for treatment; the slurry is transported to the double-cone rotary vacuum dryer 3 for slight negative pressure and drying at 120-150°C to form a finished product (about 60kg, antimony pentoxide content of about 60-70%), and the dry exhaust gas is transported to the ion cracking device 7 for treatment.

[0042] Although the present invention has been described in detail above by general description, specific implementation methods and experiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A system for treating spent antimony pentachloride catalyst used in the production of difluoromonochloromethane, characterized in that: It includes a hydrolysis device, a centrifugal device, and a drying device; The hydrolysis device is provided with a stirring device, a waste catalyst inlet, an alkali solution inlet, an oxidant inlet and a water inlet are provided on the top, a clear liquid outlet is provided on the side wall, and a slurry outlet is provided on the bottom; The slurry outlet of the hydrolysis device is connected to the inlet of the centrifugal device; The solid phase outlet of the centrifugal device is connected to the inlet of the drying device; The material of the hydrolysis device does not need to be acid-resistant.

2. The processing system according to claim 1, characterized in that The hydrolysis device is also provided with an exhaust port, which is connected to a water-alkali washing system, and the water-alkali washing system is used for water-alkali washing to treat and collect acidic gases.

3. The processing system according to claim 1, characterized in that The clear liquid outlet of the hydrolysis device is connected to the spent alkali tank.

4. The processing system according to claim 1, characterized in that The centrifugal device is a horizontal scraper discharge centrifuge.

5. The processing system according to claim 1, characterized in that The drying device is a double-cone rotary vacuum dryer.

6. The processing system according to claim 1, characterized in that It also includes a plasma cracking device, and the liquid phase outlet of the centrifugal device is connected to the plasma cracking device.

7. The processing system according to claim 6, characterized in that The drying device is provided with an exhaust port, and the exhaust port of the drying device is connected to the plasma cracking device.

8. A method for treating a waste antimony pentachloride catalyst, characterized in that: The processing system as claimed in claim 1 is used and comprises the following steps: (1) Adding industrial water to the hydrolysis device, and further adding sodium hydroxide solution to adjust the pH value to above 10; (2) adding the waste antimony pentachloride catalyst and hydrogen peroxide to the hydrolysis device respectively and continuously, maintaining a certain temperature and stirring speed for hydrolysis reaction, and the acidic gas generated in the reaction enters the water alkali washing system for water alkali washing treatment; (3) The liquid after the hydrolysis reaction is allowed to stand to separate the clear liquid and the slurry. The clear liquid enters the waste alkali tank, and the slurry enters the centrifuge for solid-liquid separation. The separated liquid phase enters the plasma cracking device, and the separated solid phase enters the dryer for drying. During the hydrolysis reaction, the pH value of the reaction system is maintained above 10 by adding sodium hydroxide solution.

9. The processing method according to claim 8, characterized in that: The temperature of the hydrolysis reaction is 50-60°C.

10. The processing method according to claim 8 or 9, characterized in that: The mass ratio of the total amount of the waste antimony pentachloride catalyst added to the industrial water is 1-5:10; and / or, the Sb in the waste antimony pentachloride catalyst added continuously 3+ The molar flow ratio of the hydrogen peroxide is 1.8-2.2:3.

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