Method and system for treating catalyst in a polysilicon disproportionation reactor column

Abstract

The application discloses a kind of polycrystalline silicon disproportionation reaction tower in the processing method and processing system of catalyst, which comprises the following steps: 1) into polycrystalline silicon disproportionation reaction tower, silicon tetrachloride reacts with dichlorodihydrogen silicon in polycrystalline silicon disproportionation reaction tower to generate trichlorosilane;2) again into silicon tetrachloride and carry out cyclic replacement, and then the silicon tetrachloride into polycrystalline silicon disproportionation reaction tower is evacuated;3) into polycrystalline silicon disproportionation reaction tower, nitrogen is replaced until the hydrogen concentration value in polycrystalline silicon disproportionation reaction tower is lower than the first preset hydrogen concentration value and stop replacement;4) into polycrystalline silicon disproportionation reaction tower, oxygen in air reacts with trichlorosilane in polycrystalline silicon disproportionation reaction tower to generate silicon dioxide, silicon tetrachloride, hydrogen chloride.The processing method is low cost, safe, environmental protection, non-toxic, high efficiency removes residual material in catalyst, reduces catalyst direct exposure risk, replacement is complete, and residual material in catalyst is effectively removed.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of polysilicon production, and particularly relates to a treatment method and a treatment system for catalysts in a polysilicon disproportionation reaction tower. BACKGROUND

[0002] In the field of polysilicon, at present, the main production method of polysilicon is the modified Siemens method. The reduction of polysilicon also produces a byproduct dichlorosilane. Dichlorosilane reacts with silicon tetrachloride in a disproportionation reaction tower to generate trichlorosilane, achieving internal circulation processing in the whole process. Adding a catalyst to the disproportionation reaction tower can improve the chemical reaction rate and increase the processing capacity, which is a relatively common method adopted by the existing polysilicon industry. Chlorosilane is a toxic gas with irritating and suffocating odor and corrosive properties, which is flammable in air and produces corrosive smoke in wet air. The boiling point of dichlorosilane (101.325 kPa) is 8.2℃, the boiling point of trichlorosilane (101.325 kPa) is 31.8℃, and the boiling point of silicon tetrachloride (101.325 kPa) is 57.6℃. Dichlorosilane is the most dangerous among them.

[0003] The catalysts in the disproportionation reaction tower will be poisoned, deactivated, and blocked after long-term use, and need to be replaced or regenerated. The danger of chlorosilane and the large specific surface area and porosity of the catalyst make it difficult to completely replace the materials in the disproportionation reaction tower, increasing the difficulty of catalyst replacement. Currently, production enterprises basically only use nitrogen to replace, and the replacement is often incomplete during catalyst replacement. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a treatment method and a treatment system for catalysts in a polysilicon disproportionation reaction tower, which is safe, environmentally friendly, and low-cost, and solves the problems of incomplete replacement and attached materials during the replacement of catalysts in the disproportionation reaction tower.

[0005] The technical solution adopted to solve the technical problem of the present application is to provide a treatment method for catalysts in a polysilicon disproportionation reaction tower, comprising the following steps:

[0006] 1) Four chlorosilane is introduced into the polysilicon disproportionation reaction tower to consume dichlorosilane, and four chlorosilane reacts with dichlorosilane in the polysilicon disproportionation reaction tower to generate trichlorosilane;

[0007] 2) Four chlorosilane is introduced again for cyclic replacement, and then the four chlorosilane introduced into the polysilicon disproportionation reaction tower is evacuated;

[0008] 3) Nitrogen is introduced into the polysilicon disproportionation reaction tower for replacement until the hydrogen concentration in the polysilicon disproportionation reaction tower is lower than the first preset hydrogen concentration value to stop replacement.

[0009] 4) air is introduced into the polysilicon dismutation reaction tower to consume trichlorosilane, and oxygen in the air reacts with trichlorosilane in the polysilicon dismutation reaction tower to generate silicon dioxide, silicon tetrachloride and hydrogen chloride.

[0010] Preferably, in step 3), nitrogen is introduced into the polysilicon dismutation reaction tower for replacement, and the pressure is charged to 0.2-0.4 MPaG, and the pressure is released to 0.02-0.10 MPaG.

[0011] Preferably, between step 3) and step 4), step i) is further included.

[0012] A blind plate is added at the connection between the polysilicon dismutation reaction tower and the external system to isolate the polysilicon dismutation reaction tower from the external operating system.

[0013] Preferably, after the blind plate is added in step i), the following steps are further included.

[0014] Nitrogen is introduced into the polysilicon dismutation reaction tower for replacement until the hydrogen concentration in the polysilicon dismutation reaction tower is lower than the second preset hydrogen concentration value, and the replacement is stopped.

[0015] Preferably, in step i), heated nitrogen is introduced into the tower kettle of the polysilicon dismutation reaction tower for replacement, and the nitrogen is gradually increased from 50°C to 100°C to 150°C to 200°C, and each temperature increase interval is 18-24h.

[0016] Preferably, in step 4), if the temperature of the catalyst section of the polysilicon dismutation reaction tower rises by more than 60°C, nitrogen is immediately introduced into the reflux pipeline at the top of the polysilicon dismutation reaction tower, and cold nitrogen is introduced into the tower kettle of the polysilicon dismutation reaction tower for air cooling and temperature reduction to below 30°C.

[0017] Preferably, after the step of introducing cold nitrogen into the tower kettle of the polysilicon dismutation reaction tower for air cooling and temperature reduction to below 30°C in step 4), the following steps are further included.

[0018] Air is introduced into the tower kettle of the polysilicon dismutation reaction tower for replacement again, and air and cold nitrogen are alternately introduced according to the change of temperature until the hydrogen chloride concentration is lower than the preset hydrogen chloride concentration value.

[0019] Preferably, after step 4), step 5) is further included.

[0020] Air is introduced into the reflux pipeline at the top of the polysilicon dismutation reaction tower, and the environment in the tower is an aerobic environment, and the tower kettle is replaced with air for 20-30 hours.

[0021] The tower is pressurized to 0.1-0.5 MPa by using air, the tower bottom is depressurized to 0.005-0.02 MPa, and the pressurization and depressurization replacement is repeated for 2-5 times.

[0022] Preferably, the step 5) is followed by a step 6):

[0023] Open the manhole of the polysilicon disproportionation reaction tower, and continuously blow air into the bottom part.

[0024] The application also provides a treatment system for the treatment method.

[0025] The polysilicon disproportionation reaction tower is used for inputting silicon tetrachloride and dichlorosilane to generate trichlorosilane, and a catalyst for catalyzing the reaction is placed in the polysilicon disproportionation reaction tower.

[0026] The silicon tetrachloride input unit is connected with the polysilicon disproportionation reaction tower, and is used for inputting silicon tetrachloride into the polysilicon disproportionation reaction tower to generate the reverse disproportionation reaction, inputting silicon tetrachloride to consume dichlorosilane, reacting silicon tetrachloride with dichlorosilane in the polysilicon disproportionation reaction tower to generate trichlorosilane, and inputting silicon tetrachloride again to circulate and replace.

[0027] The dichlorosilane input unit is connected with the polysilicon disproportionation reaction tower, and is used for inputting dichlorosilane into the polysilicon disproportionation reaction tower to generate the reverse disproportionation reaction.

[0028] The tower bottom liquid extraction unit is connected with the tower bottom of the polysilicon disproportionation reaction tower, and is used for extracting the tower bottom liquid.

[0029] The tower top tail gas condensation and circulation unit is connected with the tower top of the polysilicon disproportionation reaction tower, and is used for condensing the tower top tail gas of the polysilicon disproportionation reaction tower into trichlorosilane condensate and circulating the condensate, and obtaining the exhaust tail gas after condensation.

[0030] The exhaust tail gas unit is connected with the tower top tail gas condensation and circulation unit, and is used for extracting the exhaust tail gas.

[0031] The trichlorosilane extraction unit is connected with the tower top tail gas condensation and circulation unit, and is used for extracting the trichlorosilane condensate.

[0032] The nitrogen input unit is connected with the polysilicon disproportionation reaction tower, and is used for inputting nitrogen into the polysilicon disproportionation reaction tower to replace, until the hydrogen concentration value in the polysilicon disproportionation reaction tower is lower than the first preset hydrogen concentration value to stop the replacement.

[0033] The air input unit is connected with the polysilicon disproportionation reaction tower, and is used for inputting air into the polysilicon disproportionation reaction tower to consume trichlorosilane, and oxygen in the air reacts with trichlorosilane in the polysilicon disproportionation reaction tower to generate silicon dioxide, silicon tetrachloride and hydrogen chloride.

[0034] Preferably, the treatment system used in the treatment method described above further comprises:

[0035] The first blind plate is arranged on a connecting pipeline between the tower liquid outlet unit and the tower pot of the polysilicon disproportionation reaction tower.

[0036] The second blind plate is arranged on a connecting pipeline between the dichlorosilane input unit and the polysilicon disproportionation reaction tower.

[0037] The third blind plate is arranged on a connecting pipeline between the silicon tetrachloride input unit and the polysilicon disproportionation reaction tower.

[0038] The fourth blind plate is arranged on a connecting pipeline between the trichlorosilane outlet unit and the tower top tail gas condensation circulation unit.

[0039] The fifth blind plate is arranged on a connecting pipeline between the exhaust gas unit and the tower top tail gas condensation circulation unit.

[0040] The treatment method and treatment system of the catalyst in the polysilicon disproportionation reaction tower in the application have low cost, safety, environmental protection, non-toxicity, can efficiently remove residual materials in the catalyst, reduce the risk of direct exposure of the catalyst, completely replace and effectively remove the residual materials in the catalyst, greatly improve the safety of the catalyst replacement process, and avoid abnormal accidents such as combustion and explosion in the replacement process. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 FIG. 2 is a structural schematic diagram of the treatment system of the catalyst in the polysilicon disproportionation reaction tower in Embodiment 2 of the application.

[0042] In the figure, 1 is a polysilicon disproportionation reaction tower, 2 is a silicon tetrachloride input unit, 3 is a dichlorosilane input unit, 4 is a tower liquid outlet unit, 5 is an exhaust gas unit, 6 is a trichlorosilane outlet unit, 7 is a nitrogen gas input unit, 8 is an air input unit, 9 is a first condenser, 10 is a first circulation pump, 11 is a second condenser, 12 is a third condenser, 13 is a reflux tank, 14 is a second circulation pump, 15 is a nitrogen gas pipeline, 16 is a first blind plate, 17 is a second blind plate, 18 is a third blind plate, 19 is a fourth blind plate, 20 is a fifth blind plate, and 21 is a heater. DETAILED DESCRIPTION

[0043] In order for those skilled in the art to better understand the technical solutions of the application, the application will be further described in detail below with reference to the drawings and specific embodiments.

[0044] Embodiments of the present patent are described below in detail, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary only, for the purpose of explanation, and are not to be understood as limiting the present patent.

[0045] Embodiment 1

[0046] The present embodiment provides a method for treating catalysts in a polysilicon disproportionation reactor, comprising the following steps:

[0047] 1) introducing silicon tetrachloride into the polysilicon disproportionation reactor to consume dichlorosilane, and the silicon tetrachloride reacts with the dichlorosilane in the polysilicon disproportionation reactor to generate trichlorosilane;

[0048] 2) introducing silicon tetrachloride again for cyclic displacement, and then stopping the introduction of silicon tetrachloride into the polysilicon disproportionation reactor;

[0049] 3) introducing nitrogen into the polysilicon disproportionation reactor for displacement until the hydrogen concentration in the polysilicon disproportionation reactor is lower than a first preset hydrogen concentration value, and stopping the displacement;

[0050] 4) introducing air into the polysilicon disproportionation reactor to consume trichlorosilane, and the oxygen in the air reacts with the trichlorosilane in the polysilicon disproportionation reactor to generate silicon dioxide, silicon tetrachloride, and hydrogen chloride.

[0051] The present embodiment also provides a treatment system for the above treatment method, comprising:

[0052] a polysilicon disproportionation reactor for introducing silicon tetrachloride and dichlorosilane to generate trichlorosilane, and a catalyst for catalyzing the reaction is placed in the polysilicon disproportionation reactor;

[0053] a silicon tetrachloride input unit connected to the polysilicon disproportionation reactor, the silicon tetrachloride input unit is used to input silicon tetrachloride into the polysilicon disproportionation reactor to generate trichlorosilane through reverse disproportionation reaction, the silicon tetrachloride input unit is also used to input silicon tetrachloride to consume dichlorosilane, and the silicon tetrachloride reacts with the dichlorosilane in the polysilicon disproportionation reactor to generate trichlorosilane, and the silicon tetrachloride input unit is also used to input silicon tetrachloride again for cyclic displacement;

[0054] a dichlorosilane input unit connected to the polysilicon disproportionation reactor, the dichlorosilane input unit is used to input dichlorosilane into the polysilicon disproportionation reactor to generate trichlorosilane through reverse disproportionation reaction;

[0055] a tower kettle liquid extraction unit connected to the tower kettle of the polysilicon disproportionation reactor, the tower kettle liquid extraction unit is used to extract the tower kettle liquid;

[0056] A tower top tail gas condensation circulation unit is connected to the tower top of the polysilicon disproportionation reaction tower. The tower top tail gas condensation circulation unit is used to condense the tower top tail gas of the polysilicon disproportionation reaction tower into trichlorosilane condensate and circulate the condensate. The exhaust tail gas is obtained after condensation;

[0057] An exhaust tail gas unit is connected to the tower top tail gas condensation circulation unit. The exhaust tail gas unit is used to extract the exhaust tail gas;

[0058] A trichlorosilane extraction unit is connected to the tower top tail gas condensation circulation unit. The trichlorosilane extraction unit is used to extract the trichlorosilane condensate;

[0059] A nitrogen input unit is connected to the polysilicon disproportionation reaction tower. The nitrogen input unit inputs nitrogen into the polysilicon disproportionation reaction tower for replacement until the hydrogen concentration value in the polysilicon disproportionation reaction tower is lower than the first preset hydrogen concentration value to stop replacement;

[0060] An air input unit is connected to the polysilicon disproportionation reaction tower. The air input unit is used to input air into the polysilicon disproportionation reaction tower to consume trichlorosilane. Oxygen in the air reacts with trichlorosilane in the polysilicon disproportionation reaction tower to generate silicon dioxide, silicon tetrachloride, and hydrogen chloride.

[0061] The treatment method and treatment system of the catalyst in the polysilicon disproportionation reaction tower in the embodiment are low-cost, safe, environmentally friendly, non-toxic, and can efficiently remove residual materials in the catalyst, reduce the risk of direct exposure of the catalyst, completely replace the catalyst, and effectively remove residual materials in the catalyst, greatly improving the safety of the catalyst replacement process and avoiding abnormal accidents such as combustion and explosion during the replacement process.

[0062] Embodiment 2

[0063] As shown in Figure 1 The embodiment provides a treatment method for a catalyst in a polysilicon disproportionation reaction tower, which includes the following steps:

[0064] 1) Silicon tetrachloride is introduced into the polysilicon disproportionation reaction tower 1 to consume dichlorodihydrogen silicon. Silicon tetrachloride reacts with dichlorodihydrogen silicon in the polysilicon disproportionation reaction tower 1 to generate trichlorosilane;

[0065] 2) Silicon tetrachloride is introduced again for circulation replacement, and then the silicon tetrachloride introduced into the polysilicon disproportionation reaction tower 1 is removed;

[0066] 3) nitrogen is introduced into the polysilicon disproportionation reactor 1 for replacement, the pressure is charged to 0.2-0.4 MPaG, and the pressure is released to 0.02-0.10 MPaG until the hydrogen concentration in the polysilicon disproportionation reactor 1 is lower than the first preset hydrogen concentration value, and the replacement is stopped. In this embodiment, the replacement is performed for 10-20 times, and the hydrogen concentration is less than 100 PPM (the first preset hydrogen concentration value) when the replacement is sampled at the replacement port, and the replacement is stopped. Specifically, in this embodiment, the pressure is charged to 0.3 MPaG, the pressure is released to 0.05 MPaG, and the replacement is performed for 15 times.

[0067] 4) a blind plate is added at the connection between the polysilicon disproportionation reactor 1 and the external system to isolate the polysilicon disproportionation reactor 1 from the external operation system, so as to avoid the reverse flow of the system materials caused by the internal leakage of the valve and the like. After the blind plate is added, a nitrogen heater 21 is installed at the tank of the reactor, hot nitrogen is introduced during the replacement to improve the replacement speed of the materials. Nitrogen is introduced into the polysilicon disproportionation reactor 1 for replacement until the hydrogen concentration in the polysilicon disproportionation reactor 1 is lower than the second preset hydrogen concentration value, and the replacement is stopped. The heated nitrogen is introduced into the tank of the polysilicon disproportionation reactor 1 for replacement, and the temperature of the nitrogen is increased from 50°C to 100°C, from 100°C to 150°C, and from 150°C to 200°C in sequence, and the interval of each temperature increase is 18-24 h. Specifically, the interval of each temperature increase is 50°C to 100°C, 100°C to 150°C, and 150°C to 200°C. The pressure release port is connected to the atmosphere through a metal hose for replacement, the replacement is performed in the air while the reactor is kept in a positive pressure state, the pressure is controlled to be 10-30 kpa, the replacement port is connected to an alkali tank through a metal hose to prevent environmental pollution, and a warning line is arranged around the operation point. In order to avoid incomplete replacement and ensure the safe and environmentally-friendly replacement of the catalyst, the replacement is stopped when the hydrogen concentration is less than 50 PPM (the second preset hydrogen concentration value) when the replacement port is sampled. Specifically, the interval of each temperature increase in each temperature increase section in this embodiment is 20 h.

[0068] 5) air is introduced into the polysilicon disproportionation reactor 1 to consume trichlorosilane. Specifically, instrument air is introduced in this embodiment, and the dew point of the instrument air needs to be less than -50°C. The instrument air is introduced from the tank for continuous replacement and replacement, the residual materials in the catalyst are subjected to contact reaction, and the risk of directly contacting the air when the catalyst is disassembled is reduced. The oxygen in the air reacts with the trichlorosilane in the polysilicon disproportionation reactor 1 to generate silicon dioxide, silicon tetrachloride, and hydrogen chloride, and the reaction equation is as follows: 2SiHCl3+O2=SiO2+SiCl4+2HCl. The reaction is an exothermic reaction.

[0069] If the temperature of the upper and lower parts of the catalyst section of the polysilicon disproportionation reaction tower 1 rises by more than 60°C, nitrogen is immediately introduced into the reflux pipeline at the top of the polysilicon disproportionation reaction tower 1, and cold nitrogen is introduced into the tower bottom of the polysilicon disproportionation reaction tower 1 to cool it to below 30°C. This process requires constant attention to temperature changes to prevent rapid temperature rise and high-temperature combustion. If a reaction occurs, the HCl concentration will be > 50 ppm.

[0070] Air is again introduced into the tower bottom of the polysilicon disproportionation reaction tower 1 to displace it, and air and cold nitrogen are alternately introduced according to the temperature changes.

[0071] Displacement is continued until the temperature in the tower no longer rises, and the top temperature drops to 30°C. Displacement is maintained for at least 24 hours. The HCl concentration at the displacement port is < 3 ppm.

[0072] 6) Air is introduced into the reflux pipeline at the top of the polysilicon disproportionation reaction tower 1, and the tower environment is aerobic. The tower bottom is vented to air for 20-30 hours. Specifically, in this embodiment, the tower bottom is vented to air for 24 hours.

[0073] The tower is pressurized to 0.1-0.5 MPa using air, and the tower bottom is vented to air to 0.005-0.02 MPa. This pressurization and venting is repeated 2-5 times. Specifically, in this embodiment, the tower is pressurized to 0.2 MPa using air, and the tower bottom is vented to air to 0.01 MPa. This pressurization and venting is repeated 3 times, and the HCl concentration at the displacement port is < 3 ppm.

[0074] 7) The manhole M3 of the polysilicon disproportionation reaction tower 1 is opened, and air is continuously introduced into the bottom.

[0075] When the oxygen content in the tower reaches 18 vol% to 23.5 vol%, the construction personnel enter the tower with a long tube respirator under adequate safety protection.

[0076] Compressed air is introduced into the reflux pipeline, and the HCl content at the venting point is < 3 ppm, indicating that the trichlorosilane and hydrogen in the catalyst have reacted completely, and the catalyst is in a safe state.

[0077] It should be noted that instrument air is continuously introduced during catalyst replacement.

[0078] The lower manhole of the open manhole should not be opened until the upper catalyst is completely removed, so as to prevent the chimney effect from causing the tower to absorb wet air and causing the catalyst in the tower to generate heat.

[0079] The reaction is as follows:

[0080] SiCl4+ 3H2O = H2SiO3+ 4HCl or SiCl4+ 4H2O = H4SiO4+ 4HCl

[0081] Data detection is continuously monitored by adding online monitoring equipment for hydrogen, oxygen, and hydrogen chloride.

[0082] Safety precautions:

[0083] The hydrogen concentration measured by replacing the sampling port before adding the blind plate should be less than 100 ppm, and the hydrogen concentration should be less than 50 ppm before air replacement.

[0084] While air is being introduced, attention should be paid to the temperature of the catalyst section to prevent the remaining material in the catalyst from reacting too quickly, causing the temperature to rise too quickly and posing a safety hazard.

[0085] As shown in Figure 1 The embodiment also provides a processing system for the processing method.

[0086] A polysilicon disproportionation reaction tower 1 is used to introduce silicon tetrachloride and dichlorodihydrogen silicon to react to generate trichlorosilane, and a catalyst for catalytic reaction is placed inside the tower;

[0087] A silicon tetrachloride input unit 2 is connected to the polysilicon disproportionation reaction tower 1, and is used to input silicon tetrachloride into the polysilicon disproportionation reaction tower 1 to undergo reverse disproportionation reaction, to consume dichlorodihydrogen silicon, to react with the dichlorodihydrogen silicon in the polysilicon disproportionation reaction tower 1 to generate trichlorosilane, and to input silicon tetrachloride again for circulation replacement;

[0088] A dichlorodihydrogen silicon input unit 3 is connected to the polysilicon disproportionation reaction tower 1, and is used to input dichlorodihydrogen silicon into the polysilicon disproportionation reaction tower 1 to undergo reverse disproportionation reaction;

[0089] A tower kettle liquid circulation unit is connected to the polysilicon disproportionation reaction tower 1, and is used to circulate the tower kettle liquid of the polysilicon disproportionation reaction tower 1;

[0090] A tower kettle liquid extraction unit 4 is connected to the tower kettle of the polysilicon disproportionation reaction tower 1, and is used to extract the tower kettle liquid;

[0091] A tower top tail gas condensation circulation unit is connected to the tower top of the polysilicon disproportionation reaction tower 1, and is used to condense the tower top tail gas of the polysilicon disproportionation reaction tower 1 into trichlorosilane condensate and circulate the condensate, and to obtain discharge tail gas after condensation;

[0092] A discharge tail gas unit 5 is connected to the tower top tail gas condensation circulation unit, and is used to extract the discharge tail gas;

[0093] A trichlorosilane extraction unit 6 is connected to the tower top tail gas condensation circulation unit, and is used to extract the trichlorosilane condensate.

[0094] The nitrogen input unit 7 is connected with the polysilicon disproportionation reaction tower 1, and the nitrogen input unit 7 inputs nitrogen into the polysilicon disproportionation reaction tower 1 to displace, until the hydrogen concentration value in the polysilicon disproportionation reaction tower 1 is lower than the first preset hydrogen concentration value, the displacement is stopped.

[0095] The air input unit 8 is connected with the polysilicon disproportionation reaction tower 1, and the air input unit 8 is used for inputting air into the polysilicon disproportionation reaction tower 1 to consume trichlorosilane, and the oxygen in the air reacts with the trichlorosilane in the polysilicon disproportionation reaction tower 1 to generate silicon dioxide, silicon tetrachloride and hydrogen chloride.

[0096] The tower kettle liquid circulation unit in the embodiment includes:

[0097] The first condenser 9 is connected with the tower kettle of the polysilicon disproportionation reaction tower 1, and the first condenser 9 is used for cooling and condensing the tower kettle liquid of the polysilicon disproportionation reaction tower.

[0098] The first circulating pump 10 is connected with the first condenser 9 and the middle upper part of the polysilicon disproportionation reaction tower 1 respectively, and the first circulating pump 10 is used for pumping the tower kettle liquid of the polysilicon disproportionation reaction tower 1 into the polysilicon disproportionation reaction tower 1 to circulate.

[0099] Specifically, the tower kettle liquid extraction unit 4 is connected with the connecting pipeline between the first circulating pump 10 and the middle upper part of the polysilicon disproportionation reaction tower 1.

[0100] The tower top tail gas condensation circulation unit in the embodiment includes:

[0101] The second condenser 11 is connected with the tower top of the polysilicon disproportionation reaction tower 1, and the second condenser 11 is used for primary cooling of the tower top liquid of the polysilicon disproportionation reaction tower 1.

[0102] The third condenser 12 is connected with the second condenser 11, and the third condenser 12 is used for secondary cooling of the tower top liquid of the polysilicon disproportionation reaction tower 1.

[0103] The reflux tank 13 is connected with the third condenser 12, and the reflux tank 13 is used for receiving the condensate.

[0104] The second circulating pump 14 is connected with the reflux tank 13 and the middle upper part of the polysilicon disproportionation reaction tower 1 respectively, and the second circulating pump 14 is used for pumping the reflux liquid into the polysilicon disproportionation reaction tower 1 to circulate.

[0105] Specifically, the exhaust tail gas unit 5 is connected with the connecting pipeline between the third condenser 12 and the reflux tank 13, and the pipeline of the exhaust tail gas unit 5 is further connected with a nitrogen pipeline 15, and the nitrogen pipeline 15 is used for inputting nitrogen to perform purging.

[0106] The treatment of the catalyst in the polysilicon disproportionation reaction tower 1 in the embodiment also includes:

[0107] The heater 21 is connected with the tower kettle of the polysilicon disproportionation reaction tower 1 and also connected with the lower part of the polysilicon disproportionation reaction tower 1. The heater 21 is used to heat the nitrogen gas and then send it into the polysilicon disproportionation reaction tower 1.

[0108] Preferably, the treatment system used in the treatment method described above also includes:

[0109] The first blind plate 16 is arranged on the connecting pipeline between the tower kettle liquid extraction unit 4 and the tower kettle of the polysilicon disproportionation reaction tower 1. The first blind plate 16 is used to separate the tower kettle of the polysilicon disproportionation reaction tower 1 from the tower kettle liquid extraction unit 4.

[0110] The second blind plate 17 is arranged on the connecting pipeline between the dichlorodihydrogen silicon input unit 3 and the polysilicon disproportionation reaction tower 1. The second blind plate 17 is used to separate the polysilicon disproportionation reaction tower 1 from the dichlorodihydrogen silicon input unit 3.

[0111] The third blind plate 18 is arranged on the connecting pipeline between the silicon tetrachloride input unit 2 and the polysilicon disproportionation reaction tower 1. The third blind plate 18 is used to separate the polysilicon disproportionation reaction tower 1 from the silicon tetrachloride input unit 2.

[0112] The fourth blind plate 19 is arranged on the connecting pipeline between the trichlorosilane extraction unit 6 and the overhead tail gas condensation circulation unit. The fourth blind plate 19 is used to separate the polysilicon disproportionation reaction tower 1 from the trichlorosilane extraction unit 6.

[0113] The fifth blind plate 20 is arranged on the connecting pipeline between the exhaust gas unit 5 and the overhead tail gas condensation circulation unit. The fifth blind plate 20 is used to separate the polysilicon disproportionation reaction tower 1 from the exhaust gas unit 5.

[0114] The polysilicon disproportionation reaction tower 1 is a device for producing trichlorosilane by reacting dichlorodihydrogen silicon and silicon tetrachloride. A catalyst is placed in the tower to improve conversion efficiency and increase production capacity. During catalyst replacement, due to the porous nature of the catalyst, there may be incomplete displacement, and the mixed chlorosilanes on the surface of the catalyst may undergo hydrolysis reaction when exposed to water, resulting in smoking and heat release. If the heat cannot be timely removed, there is a risk of spontaneous combustion, making the replacement process extremely difficult.

[0115] The treatment method and treatment system for the catalyst in the polysilicon disproportionation reaction tower 1 in the embodiment are low-cost, safe, environmentally friendly, non-toxic, and can efficiently remove residual materials from the catalyst, reducing the risk of direct exposure of the catalyst. The replacement is complete and effectively removes the residual materials in the catalyst, greatly improving the safety of the catalyst replacement process and avoiding abnormal accidents such as combustion and explosion during the replacement process.

[0116] Embodiment 3

[0117] The embodiment provides a treatment method of a catalyst in a polysilicon disproportionation reaction tower using the treatment system in the embodiment 2, and the difference from the method in the embodiment 2 is that:

[0118] Step 3) nitrogen is introduced into the polysilicon disproportionation reaction tower 1 for replacement, the pressure is charged to 0.2 MPaG, the pressure is released to 0.10 MPaG, and the replacement is recycled for 20 times.

[0119] Step 4) the nitrogen is gradually increased from 50 DEG C to 100 DEG C, 150 DEG C to 200 DEG C, and each temperature interval is 24 h.

[0120] Step 6) air is introduced into the polysilicon disproportionation reaction tower 1 through a reflux pipeline at the top of the tower, the environment in the tower is aerobic, the tower is replaced with air for 20 hours, the tower is charged with air to 0.5 MPa, and the tower is released to 0.005 MPa, and the replacement is repeated for 2 times.

[0121] Compressed air is introduced through a rectifying column reflux pipeline, and the HCl content is detected at a release point <3 ppm, which indicates that the trichlorosilane and hydrogen in the catalyst have been completely reacted, and the catalyst is in a safe state.

[0122] The treatment method and the treatment system of the catalyst in the polysilicon disproportionation reaction tower 1 in the embodiment can efficiently remove residual materials in the catalyst, reduce the risk of direct exposure of the catalyst, completely replace the residual materials in the catalyst, and greatly improve the safety of the catalyst replacement process, so that abnormal accidents such as combustion and explosion are avoided in the replacement process.

[0123] Embodiment 4

[0124] The embodiment provides a treatment method of a catalyst in a polysilicon disproportionation reaction tower using the treatment system in the embodiment 2, and the difference from the method in the embodiment 2 is that:

[0125] Step 3) nitrogen is introduced into the polysilicon disproportionation reaction tower 1 for replacement, the pressure is charged to 0.4 MPaG, the pressure is released to 0.02 MPaG, and the replacement is recycled for 10 times.

[0126] Step 4) the nitrogen is gradually increased from 50 DEG C to 100 DEG C, 150 DEG C to 200 DEG C, and each temperature interval is 18 h.

[0127] Step 6) air is introduced into the polysilicon disproportionation reaction tower 1 through a reflux pipeline at the top of the tower, the environment in the tower is aerobic, the tower is replaced with air for 30 hours, the tower is charged with air to 0.1 MPa, and the tower is released to 0.02 MPa, and the replacement is repeated for 5 times.

[0128] Through the rectifying column backflow pipeline into compressed air, the release point detects HCl content <3ppm, indicating that the trichlorosilane and hydrogen in the catalyst have been completely reacted, and the catalyst is in a safe state.

[0129] The treatment method and treatment system of the catalyst in the polysilicon dismutation reaction tower 1 in the embodiment are low-cost, safe, environmentally friendly, non-toxic, can efficiently remove residual materials in the catalyst, reduce the risk of direct exposure of the catalyst, completely replace and effectively remove the residual materials in the catalyst, greatly improve the safety of the catalyst replacement process, and avoid abnormal accidents such as combustion and explosion during the replacement process.

[0130] It can be understood that the above embodiments are only exemplary embodiments for illustrating the principles of the present application, but the present application is not limited thereto. Various modifications and improvements can be made by those of ordinary skill in the art without departing from the spirit and essence of the present application, and these modifications and improvements are also considered within the protection scope of the present application.

Claims

1. A method of treating a catalyst in a polysilicon disproportionation reactor column, characterized by, The method comprises the following steps: 1) introducing silicon tetrachloride into the polysilicon dismutation reaction tower to consume dichlorosilane, so that the silicon tetrachloride reacts with the dichlorosilane in the polysilicon dismutation reaction tower to generate trichlorosilane; 2) introducing silicon tetrachloride again to perform cyclic replacement, and then stopping the introduction of silicon tetrachloride into the polysilicon dismutation reaction tower; 3) introducing nitrogen into the polysilicon dismutation reaction tower to perform replacement until the hydrogen concentration in the polysilicon dismutation reaction tower is lower than a first preset hydrogen concentration value, and then stopping the replacement; i) adding a blind plate at the connection between the polysilicon dismutation reaction tower and the external system to isolate the polysilicon dismutation reaction tower from the external system; introducing nitrogen into the polysilicon dismutation reaction tower to perform replacement, introducing heated nitrogen into the tower bottom of the polysilicon dismutation reaction tower to perform replacement, and gradually increasing the temperature of the nitrogen from 50℃ to 100℃, from 100℃ to 150℃, and from 150℃ to 200℃ at an interval of 18-24 hours until the hydrogen concentration in the polysilicon dismutation reaction tower is lower than a second preset hydrogen concentration value, and then stopping the replacement; 4) introducing air into the polysilicon dismutation reaction tower to consume trichlorosilane, so that the oxygen in the air reacts with the trichlorosilane in the polysilicon dismutation reaction tower to generate silicon dioxide, silicon tetrachloride and hydrogen chloride.

2. The method of claim 1, wherein the catalyst is treated in a polysilicon disproportionation reactor. In the step 3), the nitrogen is introduced into the polysilicon dismutation reaction tower to perform replacement, and the pressure is charged to 0.2-0.4 MPaG and discharged to 0.02-0.10 MPaG.

3. The method of claim 1, wherein the catalyst is a catalyst for a polysilicon disproportionation reaction. In the step 4), if the temperature of the catalyst section of the polysilicon dismutation reaction tower rises by more than 60℃, nitrogen is immediately introduced into the reflux pipeline at the top of the polysilicon dismutation reaction tower, and cold nitrogen is introduced into the tower bottom of the polysilicon dismutation reaction tower to perform air blowing and cooling to below 30℃.

4. The method of claim 3, wherein the catalyst is treated in a polysilicon disproportionation reactor. After the step of introducing cold nitrogen into the tower bottom of the polysilicon dismutation reaction tower to perform air blowing and cooling to below 30℃ in the step 4), the method further comprises the following steps: Air is introduced into the tower bottom of the polysilicon dismutation reaction tower again to perform replacement, and air and cold nitrogen are alternately introduced according to the change of the temperature until the hydrogen chloride concentration is lower than a preset hydrogen chloride concentration value.

5. The method of claim 1, wherein the catalyst is a catalyst for a polysilicon disproportionation reaction tower. The method further comprises the following step 5) after the step 4): Air is introduced into the reflux pipeline at the top of the polysilicon dismutation reaction tower, the environment in the tower is an oxygen-containing environment, and the tower bottom is continuously blown by air for 20-30 hours; The tower is repeatedly charged with air to 0.1-0.5 MPa and discharged to 0.005-0.02 MPa for 2-5 times.

6. The method of claim 5, wherein the catalyst is treated in a polysilicon disproportionation reactor. The method further comprises the following step 6) after the step 5): A manhole of the polysilicon dismutation reaction tower is opened, and air is continuously blown into the tower bottom.

7. A processing system for use in the processing method according to any one of claims 1 to 6, characterized in that The method comprises: a polysilicon dismutation reaction tower for introducing silicon tetrachloride and dichlorosilane to generate trichlorosilane, and a catalyst for catalyzing the reaction is arranged in the polysilicon dismutation reaction tower; a silicon tetrachloride input unit connected with the polysilicon dismutation reaction tower, the silicon tetrachloride input unit is used for introducing silicon tetrachloride into the polysilicon dismutation reaction tower to perform reverse dismutation reaction, and is also used for introducing silicon tetrachloride to consume dichlorosilane, so that the silicon tetrachloride reacts with the dichlorosilane in the polysilicon dismutation reaction tower to generate trichlorosilane, and is further used for introducing silicon tetrachloride again to perform cyclic replacement; A dichlorodihydrogen silicon input unit is connected with the polysilicon dismutation reaction tower, and is used for inputting dichlorodihydrogen silicon into the polysilicon dismutation reaction tower to generate a reverse dismutation reaction; A tower kettle liquid extraction unit is connected with the tower kettle of the polysilicon dismutation reaction tower, and is used for extracting the tower kettle liquid; A tower top tail gas condensation circulation unit is connected with the tower top of the polysilicon dismutation reaction tower, and is used for condensing the tower top tail gas of the polysilicon dismutation reaction tower into trichlorosilane condensate and circulating the condensate, and obtaining exhaust tail gas after condensation; An exhaust tail gas unit is connected with the tower top tail gas condensation circulation unit, and is used for extracting the exhaust tail gas; A trichlorosilane extraction unit is connected with the tower top tail gas condensation circulation unit, and is used for extracting the trichlorosilane condensate; A nitrogen input unit is connected with the polysilicon dismutation reaction tower, and is used for inputting nitrogen into the polysilicon dismutation reaction tower to replace, until the hydrogen concentration value in the polysilicon dismutation reaction tower is lower than a first preset hydrogen concentration value to stop the replacement; An air input unit is connected with the polysilicon dismutation reaction tower, and is used for inputting air into the polysilicon dismutation reaction tower to consume trichlorosilane, and oxygen in the air reacts with trichlorosilane in the polysilicon dismutation reaction tower to generate silicon dioxide, silicon tetrachloride and hydrogen chloride.

8. The processing system of claim 7, wherein, Further comprising: A first blind plate is arranged on a connecting pipeline between the tower kettle liquid extraction unit and the tower kettle of the polysilicon dismutation reaction tower; A second blind plate is arranged on a connecting pipeline between the dichlorodihydrogen silicon input unit and the polysilicon dismutation reaction tower; A third blind plate is arranged on a connecting pipeline between the silicon tetrachloride input unit and the polysilicon dismutation reaction tower; A fourth blind plate is arranged on a connecting pipeline between the trichlorosilane extraction unit and the tower top tail gas condensation circulation unit; A fifth blind plate is arranged on a connecting pipeline between the exhaust tail gas unit and the tower top tail gas condensation circulation unit.

Images