Texturing etching tail gas treatment process and system in passivation back contact battery production

Abstract

The invention discloses a process and a system for treating texturing etching tail gas in passivation back contact battery production, the system comprises a rotating packed bed, a supergravity rotating adsorption bed and an absorption liquid storage container, oxidation absorption liquid is stored in the absorption liquid storage container, and the texturing etching tail gas to be treated is firstly input into the rotating packed bed; and meanwhile, the oxidation absorption liquid in the absorption liquid storage container is pumped into the rotating packed bed to react with the texturing etching tail gas, and the reacted tail gas enters the supergravity rotating adsorption bed, is purified by the supergravity rotating adsorption bed and is discharged after reaching the standard. Aiming at the characteristics of pollutants in the texturing etching tail gas generated in the production process of the passivated back contact battery, an efficient treatment scheme is provided, the rotating packed bed and the supergravity rotating adsorption bed are adopted as reactors to treat the texturing etching tail gas, efficient purification of the pollutants in the texturing etching tail gas can be achieved, and the quality of the texturing etching tail gas is improved. And the discharged tail gas can meet the requirements of related standards.

Description

Technical Field

[0001] The present invention relates to the technical field of waste gas treatment, and in particular to a process and system for treating tail gas from texturing and etching in the production of passivated back contact batteries. Background Art

[0002] Crystalline silicon solar cells are the most technologically mature of all solar cell types, boasting a comprehensive R&D, manufacturing, and market supply chain, and are playing an increasingly important role in the new energy sector. As the conversion efficiency of P-type cells approaches its ceiling, N-type cell technology is emerging as a promising approach. N-type cell technology primarily encompasses three key areas: tunneling oxide passivation contact (TOPCon), heterojunction (HJT), and interdigitated back contact (IBC). In recent years, some leading photovoltaic companies have leveraged the electrical advantages of TOPCon technology and the optical advantages of IBC technology, integrating the two to form passivated back contact (TBC) solar cells. During the production of passivated back contact (TBC) batteries, nitric acid and hydrofluoric acid need to be added to the etching tank during the wet etching and PSG removal process. The silicon is oxidized by nitric acid, and the hydrofluoric acid dissolves the silicon oxide in the solution. The solution is then rinsed with pure water. HNO3 and HF react with Si to produce H2SiF6, NO2, and NO, generating acidic waste gas containing nitrogen oxides (mainly NO2 and NO).

[0003] For the texturing and etching exhaust gas generated in the production process of passivated back contact batteries (TBC), the traditional treatment technology is to use a spray tower. When the exhaust gas flows from bottom to top through the packing layer, the washing liquid is evenly sprayed on the surface of the packing layer from the nozzle. The exhaust gas and the spray liquid are fully contacted and absorbed in the gas-liquid two-phase. The pollutants in the exhaust gas are absorbed into the washing liquid by physical and chemical absorption, thereby achieving the purpose of removing pollutants. The whole reaction process will produce by-products such as hydrochloric acid, sodium sulfate, sodium bisulfate, sulfur, sodium chloride, and sodium nitrate. The reaction process is complex and unstable, the by-product composition is complex, and the chemicals contained in the denitrification waste liquid are difficult to separate and purify, resulting in serious secondary pollution, large chemical consumption, high operating costs, and serious corrosion to equipment. Therefore, it is urgent to develop an economical, practical and efficient texturing and etching exhaust gas treatment solution. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a texturing and etching tail gas treatment process and system in the production of passivated back contact cells in view of the deficiencies in the above-mentioned prior art.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: In the first aspect of the present invention, a texturing and etching tail gas treatment system in the production of passivated back contact cells is provided, comprising a rotating packed bed, a high-gravity rotating adsorption bed and an absorption liquid storage container:

[0006] The rotor blades in the high-gravity rotating adsorption bed are loaded with polyethylene glycol modified adsorbent fillers, and the absorption liquid storage container is filled with oxidizing absorption liquid. The texturing and etching tail gas to be treated is first input into the rotating packed bed, and at the same time, the oxidizing absorption liquid in the absorption liquid storage container is pumped into the rotating packed bed to react with the texturing and etching tail gas. The tail gas after the reaction enters the high-gravity rotating adsorption bed, and is purified by the high-gravity rotating adsorption bed before being discharged in compliance with the emission standards.

[0007] The method for loading the polyethylene glycol modified adsorbent filler on the rotor blades is as follows:

[0008] The adsorbent powder, polyethylene glycol and silane coupling agent are mixed, and then a dispersant is added and ball milled to obtain a polyethylene glycol modified adsorbent suspension. The rotor blades are immersed in the polyethylene glycol modified adsorbent suspension, dried, and loaded on the rotor blades to form a polyethylene glycol modified adsorbent filler.

[0009] Preferably, the method for loading the polyethylene glycol modified adsorbent filler on the rotor blade is:

[0010] The adsorbent powder, polyethylene glycol, and silane coupling agent are mixed in a mass ratio of 100:20 to 40:1, and then a dispersant PVP is added and ball milled to obtain a uniform polyethylene glycol-modified adsorbent suspension. The rotor blade is immersed in the polyethylene glycol-modified adsorbent suspension for 5-20 minutes, pulled to form a uniform wet film, and dried. The immersion, pulling, and drying operations are repeated 2 to 3 times to form a polyethylene glycol-modified adsorbent filler with a thickness of 120 to 150 μm on the rotor blade.

[0011] Preferably, the adsorbent powder is at least one of silica gel powder, graphite powder, activated carbon powder, and zeolite powder.

[0012] Preferably, the oxidation absorption liquid is a mixture of 20-40 wt% sodium chlorite solution and 30-70 wt% sulfuric acid solution in a mass ratio of 2.5-10:0.5-2.

[0013] Preferably, the rotating packed bed includes a shell, a packing rotor rotatably arranged in the shell, a first motor for driving the packing rotor to rotate, a liquid distributor arranged in the middle of the packing rotor, a gas inlet arranged on the side of the shell, a gas outlet arranged on the upper part of the shell, and a liquid outlet arranged at the bottom of the shell.

[0014] Preferably, the supergravity rotating adsorption bed includes a shell, a rotating shaft rotatably arranged in the shell, a rotor assembly arranged on the rotating shaft, an air inlet opened on the shell, and a second motor for driving the rotating shaft to rotate.

[0015] Preferably, the rotating shaft includes an upper rotating shaft portion and a lower rotating shaft portion, the rotor assembly is connected between the upper rotating shaft portion and the lower rotating shaft portion, and the rotor assembly includes an upper rotor disk connected to the bottom end of the upper rotating shaft portion, a lower rotor disk connected to the upper end of the lower rotating shaft portion, and a plurality of rotor blades with a wire mesh structure connected between the upper rotor disk and the lower rotor disk and arranged in an annular shape;

[0016] The upper rotating shaft portion is hollow inside to form an exhaust channel. The upper rotor disc is provided with an exhaust through hole connected to the bottom of the exhaust channel. The upper end of the exhaust channel forms an exhaust port.

[0017] Preferably, the system further comprises an absorption liquid output pipeline and an absorption liquid recovery pipeline connected to the absorption liquid storage container, a delivery pump provided on the absorption liquid output pipeline, and a gas delivery pipeline connecting the rotating packed bed to the high-gravity rotating adsorption bed;

[0018] The outlet end of the absorption liquid output pipeline is connected to the bottom of the liquid distributor, the inlet end of the absorption liquid recovery pipeline is connected to the liquid outlet of the rotating packed bed, the inlet end of the gas delivery pipeline is connected to the gas outlet at the upper end of the rotating packed bed, and the outlet end of the gas delivery pipeline is connected to the air inlet of the supergravity rotating adsorption bed.

[0019] A second aspect of the present invention provides a process for treating tail gas from texturing and etching in the production of a passivated back contact cell, wherein the system described above is used to treat the tail gas from texturing and etching, and the process comprises the following steps:

[0020] S1, inputting the texturing etching tail gas to be treated into a rotating packed bed, and at the same time pumping an oxidizing absorption liquid into the rotating packed bed to react with the texturing etching tail gas, the tail gas after the reaction is discharged, and the oxidizing absorption liquid after the reaction is refluxed into the absorption liquid storage container;

[0021] S2. The exhaust gas discharged from the rotating packed bed enters the super gravity rotating adsorption bed and is purified by the super gravity rotating adsorption bed material before being discharged in compliance with the emission standards.

[0022] Preferably, the texturing and etching tail gas treatment process in the production of the passivated back contact battery comprises the following steps:

[0023] S1. Add sodium chlorite solution and sulfuric acid solution to an absorption liquid storage container, mix them evenly to obtain an oxidizing absorption liquid, input the texturing etching tail gas to be treated into a rotating packed bed, and at the same time pump the oxidizing absorption liquid in the absorption liquid storage container into the rotating packed bed to react with the texturing etching tail gas, discharge the tail gas after the reaction, and reflux the oxidizing absorption liquid after the reaction into the absorption liquid storage container;

[0024] S2. The exhaust gas discharged from the rotating packed bed enters the high-gravity rotating adsorption bed. The speed of the high-gravity rotating adsorption bed is controlled at 800-1200rpm and the high-gravity factor is 100-300. The exhaust gas is purified by the polyethylene glycol modified adsorbent filler on the rotor blades and then passes through the exhaust through-hole, exhaust channel and exhaust port in sequence to meet the emission standards.

[0025] The beneficial effects of the present invention are:

[0026] The present invention aims at the characteristics of pollutants in the texturing and etching exhaust gas generated in the production process of passivated back contact batteries (TBCs), and proposes a new and efficient treatment scheme. The scheme adopts a gas-liquid high-efficiency rotating absorption reaction bed (rotating packed bed) and a supergravity rotating adsorption bed as reactors to treat the texturing and etching exhaust gas, which can achieve efficient purification of pollutants in the texturing and etching exhaust gas, and the exhaust gas discharge can meet the requirements of relevant standards.

[0027] In the rotating packed bed of the present invention, NaClO2 and H2SO4 are used as oxidation absorbers. The ClO2 generated by the reaction can react with NO in the gas phase to oxidize NO into NO2, thereby overcoming the disadvantage that NO is slightly soluble in water and cannot be oxidized in water. At the same time, the high-gravity environment of the rotating packed bed can significantly increase the gas-liquid contact area, reduce the mass transfer resistance, and accelerate the reaction rate.

[0028] After purification by the rotating packed bed, the exhaust gas enters the high-gravity rotating adsorption bed. Thanks to high gas-phase mass transfer and the action of the fillers on the rotor blades, pollutants in the exhaust gas undergo a two-phase adsorption removal process involving liquid-phase complexation and solid-phase adsorption. Polyethylene glycol absorbs NO₂ and forms nitrate ester molecules with it. Once the fillers on the rotor blades are saturated with adsorption, thermal desorption can be used to remove the polyethylene glycol-modified adsorbent. The desorbed adsorbent is a highly selective oxidant suitable for the oxidation of some organic compounds.

[0029] The present invention adopts a rotating packed bed and a supergravity rotating adsorption bed as reactors, which can achieve more compact, efficient and stable treatment of texturing and etching tail gas. Compared with traditional spray tower equipment, the volume of the reactor of the present invention is greatly reduced, which can save equipment cost and floor space. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic structural diagram of a texturing and etching tail gas treatment system in the production of a passivated back contact cell according to Example 1;

[0031] Figure 2 Schematic diagram of the structure of the rotating packed bed of Example 1;

[0032] Figure 3 This is a schematic structural diagram of the high-gravity rotating adsorption bed of Example 1.

[0033] Description of reference numerals:

[0034] 1—rotating packed bed; 11—housing; 12—packing rotor; 13—first motor; 14—liquid distributor; 15—gas inlet; 16—gas outlet; 17—liquid outlet;

[0035] 2—supergravity rotating adsorption bed; 21—housing; 22—rotating shaft; 23—rotor assembly; 24—air inlet; 25—bearing; 26—sealing ring; 221—upper rotating shaft; 222—lower rotating shaft; 223—exhaust channel; 224—exhaust port; 231—upper rotor disk; 232—lower rotor disk; 233—rotor blades;

[0036] 3—Absorption liquid storage container; 4—Absorption liquid output pipeline; 5—Absorption liquid recovery pipeline; 6—Transfer pump; 7—Gas transmission pipeline. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below with reference to the embodiments so that those skilled in the art can implement the invention with reference to the description.

[0038] It should be understood that terms such as “having”, “including” and “comprising” used herein do not preclude the existence or addition of one or more other elements or combinations thereof.

[0039] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Materials and reagents used in the following examples are commercially available unless otherwise specified. In the following examples, where specific conditions are not specified, the experiments were conducted under conventional conditions or those recommended by the manufacturer. Reagents and instruments used, where the manufacturer is not specified, are commercially available conventional products.

[0040] The present invention provides a texturing and etching tail gas treatment system in the production of passivated back contact batteries, comprising a rotating packed bed 1 (or called a gas-liquid high-efficiency rotating absorption reaction bed), a supergravity rotating adsorption bed 2, an absorption liquid storage container 3, an absorption liquid output pipeline 4 and an absorption liquid recovery pipeline 5 connected to the absorption liquid storage container 3, a delivery pump 6 arranged on the absorption liquid output pipeline 4, and a gas delivery pipeline 7 connecting the rotating packed bed 1 to the supergravity rotating adsorption bed 2.

[0041] The rotating packed bed 1 includes a shell 11, a packing rotor 12 rotatably arranged in the shell 11, a first motor 13 for driving the packing rotor 12 to rotate, a liquid distributor 14 arranged in the middle of the packing rotor 12, a gas inlet 15 arranged on the side of the shell 11, a gas outlet arranged on the upper part of the shell 11, and a liquid outlet 17 arranged at the bottom of the shell 11.

[0042] The high-gravity rotating adsorption bed 2 includes a shell 21, a rotating shaft 22 rotatably arranged in the shell 21, a rotor assembly 23 arranged on the rotating shaft 22, an air inlet 24 opened on the shell 21, and a second motor for driving the rotating shaft 22 to rotate.

[0043] The rotating shaft 22 includes an upper rotating shaft portion 221 and a lower rotating shaft portion 222, and the rotor assembly 23 is connected between the upper rotating shaft portion 221 and the lower rotating shaft portion 222. The rotor assembly 23 includes an upper rotor disk 231 connected to the bottom end of the upper rotating shaft portion 221, a lower rotor disk 232 connected to the upper end of the lower rotating shaft portion 222, and a plurality of rotor blades 233 of a wire mesh structure connected between the upper rotor disk 231 and the lower rotor disk 232 and arranged in an annular shape. In a preferred embodiment, 12 rotor blades 233 are included, the spacing between the rotor blades 233 is set to 30°, the blades are evenly distributed radially, and the rotor blades 233 are made of stainless steel wire mesh.

[0044] The upper shaft portion 221 is hollow inside to form an exhaust channel 223 . The upper rotor disk 231 is provided with an exhaust hole connected to the bottom of the exhaust channel 223 . An exhaust port 224 is formed at the upper end of the exhaust channel 223 .

[0045] Among them, the outlet end of the absorption liquid output pipeline 4 is connected to the bottom of the liquid distributor 14, the inlet end of the absorption liquid recovery pipeline 5 is connected to the liquid outlet 17 of the rotating packed bed 1, the inlet end of the gas delivery pipeline 7 is connected to the gas outlet at the upper end of the rotating packed bed 1, and the outlet end of the gas delivery pipeline 7 is connected to the air inlet 24 of the supergravity rotating adsorption bed 2.

[0046] In a preferred embodiment, the rotor blades 233 in the supergravity rotating adsorption bed 2 are loaded with polyethylene glycol modified adsorbent fillers, and the absorption liquid storage container 3 stores oxidizing absorption liquid. The texturing and etching exhaust gas to be treated is first input into the rotating packed bed 1, and at the same time, the oxidizing absorption liquid in the absorption liquid storage container 3 is pumped into the rotating packed bed 1 to react with the texturing and etching exhaust gas. The exhaust gas after the reaction enters the supergravity rotating adsorption bed 2, and is purified by the supergravity rotating adsorption bed 2 before being discharged in compliance with the standards.

[0047] In a preferred embodiment, the method for loading the polyethylene glycol modified adsorbent filler on the rotor blade 233 is:

[0048] The adsorbent powder, polyethylene glycol, and silane coupling agent are mixed in a mass ratio of 100:20 to 40:1, and then a dispersant PVP (polyvinyl pyrrolidone) is added and ball milled to obtain a uniform polyethylene glycol-modified adsorbent suspension. The rotor blade 233 is immersed in the polyethylene glycol-modified adsorbent suspension for 5-20 minutes, and slowly pulled to form a uniform wet film. Drying is repeated 2 to 3 times to form a polyethylene glycol-modified adsorbent filler with a thickness of 120 to 150 μm on the rotor blade 233.

[0049] In a preferred embodiment, the adsorbent powder is at least one of silica gel powder, graphite powder, activated carbon powder, and zeolite powder.

[0050] In a preferred embodiment, the oxidation absorption liquid is a mixture of 20-40 wt% sodium chlorite solution and 30-70 wt% sulfuric acid solution in a mass ratio of 2.5-10:0.5-2.

[0051] The present invention also provides a texturing and etching tail gas treatment process in the production of passivated back contact cells, which uses the above system to treat the texturing and etching tail gas. The process includes the following steps:

[0052] S1, inputting the texturing etching tail gas to be treated into the rotating packed bed 1, and at the same time pumping the oxidizing absorption liquid into the rotating packed bed 1 to react with the texturing etching tail gas, the tail gas after the reaction is discharged, and the oxidizing absorption liquid after the reaction is refluxed into the absorption liquid storage container 3;

[0053] S2. The tail gas discharged from the rotating packed bed 1 enters the supergravity rotating adsorption bed 2, and is purified by the material of the supergravity rotating adsorption bed 2 before being discharged in compliance with the emission standards.

[0054] In a preferred embodiment, the texturing and etching tail gas treatment process in the production of a passivated back contact cell comprises the following steps:

[0055] S1, add sodium chlorite solution and sulfuric acid solution to the absorption liquid storage container 3, mix them evenly to obtain oxidation absorption liquid, and remove the texturing etching tail gas to be treated (the main pollutant is NOx, containing a small amount of HF and sulfuric acid mist, in some embodiments, the NOx concentration is 320-430 mg / m 3 , NO2 concentration is 190~270mg / m 3 , NO concentration is 130~160mg / m 3 HF concentration <10 mg / m 3) is input into the rotating packed bed 1, and at the same time, the oxidized absorption liquid in the absorption liquid storage container 3 is pumped into the rotating packed bed 1. The oxidized absorption liquid is evenly distributed on the surface of the packing rotor 12 in the rotating packed bed 1 by the liquid distributor 14, and reacts with the texturing etching tail gas. The gas-liquid two phases are fully in contact, and a series of absorption and oxidation reactions occur, and the reaction is rapid; the tail gas after the reaction is discharged, and the oxidized absorption liquid after the reaction is refluxed into the absorption liquid storage container 3 for recycling; the main reactions occurring at this stage are as follows:

[0056] NaClO2+H2SO4→NaHSO4+HClO2

[0057] 8HClO2→6ClO2+Cl2+4H2O;

[0058] 2NO+ClO2→2NO2+Cl2+O2

[0059] Exhaust gas from rotating packed bed S2 enters high-gravity rotating adsorption bed 2, which operates at a speed of 800-1200 rpm and a high-gravity factor of 100-300. After being purified by the polyethylene glycol-modified adsorbent filler on rotor blades 233, the exhaust gas passes sequentially through exhaust holes, exhaust passage 223, and exhaust port 224 before reaching standard discharge. High-gravity rotating adsorption bed 2 offers advantages such as low pressure drop, high gas-phase mass transfer coefficient, and optimized gas flow, enabling efficient purification and removal of pollutants from exhaust gas, ensuring standard exhaust emissions.

[0060] In the rotating packed bed 1 of the present invention, NaClO2 and H2SO4 react to generate ClO2, which reacts with NO in the gas phase, oxidizing NO to NO2. This overcomes the drawback of NO being slightly soluble in water and unable to be oxidized in water. Furthermore, the high-gravity environment of the gas-liquid high-efficiency rotating absorption reactor significantly increases the gas-liquid contact area, reduces mass transfer resistance, and accelerates the reaction rate.

[0061] In a preferred embodiment, the corrugated plate packing (PVDF material) in the packing rotor 12 forms a tortuous channel, enhances turbulence, reduces the risk of liquid retention and scaling, and avoids erosion caused by the highly corrosive ClO2 gas generated by the reaction, thereby enhancing the service life of the packing.

[0062] The purified exhaust gas enters the high-gravity rotating adsorption bed 2. Thanks to high gas-phase mass transfer and the action of the filler on the rotor blades 233, pollutants in the exhaust gas undergo a two-phase adsorption removal process involving liquid-phase complexation and solid-phase adsorption. The polyethylene glycol absorbs NO₂ and forms nitrate molecules with it. Once the filler on the rotor blades 233 is saturated with adsorption, thermal desorption can be used to remove the polyethylene glycol-modified adsorbent. The resulting adsorbent is a highly selective oxidant suitable for the oxidation of some organic compounds.

[0063] In the high-gravity rotating adsorption bed 2 of the present invention, a polyethylene glycol-modified adsorbent filler is used to treat the tail gas after the initial purification of the rotating packed bed 1. This allows for efficient adsorption and purification of pollutants such as NO2 and Cl2 generated by the reaction in the rotating packed bed 1. NO2 is absorbed by the polyethylene glycol to form nitrate molecules. The polyethylene glycol-modified adsorbent filler treats the tail gas after the initial purification of the rotating packed bed 1. NO2 in the tail gas is adsorbed, and the filler and the tail gas undergo a two-phase adsorption and removal process of liquid phase complexation and solid phase adsorption. The polyethylene glycol absorbs NO2 to form nitrate molecules, which are then adsorbed and encapsulated by the porous adsorbent material with a large specific surface area in an alcohol atmosphere, thereby effectively removing nitrogen oxides. The polyethylene glycol absorption of NO2 occurs in three stages: first, NO2 is adsorbed in a free state on the outside of the polyethylene glycol liquid membrane. Then, NO2 enters the polyethylene glycol liquid membrane and forms a nitrite with the polyethylene glycol. The nitrite structure gradually transforms into a highly stable nitrate structure.

[0064] The content of pollutants such as HF and Cl2 generated in the rotating packed bed 1 is very small and can be removed by physical adsorption in the high-gravity rotating adsorption bed 2.

[0065] The present invention adopts a rotating packed bed 1 and a supergravity rotating adsorption bed 2 as reactors, which can achieve more compact, efficient and stable treatment of texturing etching tail gas. Compared with traditional spray tower equipment, the volume of the reactor of the present invention is greatly reduced, which can save equipment cost and floor space.

[0066] The above is the overall concept of the present invention. Detailed examples and comparative examples are provided below to further illustrate the present invention.

[0067] Example 1

[0068] A texturing and etching tail gas treatment system in the production of passivated back contact batteries includes a rotating packed bed 1 (or called a gas-liquid high-efficiency rotating absorption reaction bed), a supergravity rotating adsorption bed 2, an absorption liquid storage container 3, an absorption liquid output pipeline 4 and an absorption liquid recovery pipeline 5 connected to the absorption liquid storage container 3, a delivery pump 6 arranged on the absorption liquid output pipeline 4, and a gas delivery pipeline 7 connecting the rotating packed bed 1 to the supergravity rotating adsorption bed 2.

[0069] In this embodiment, the rotating packed bed 1 includes a shell 11, a packing rotor 12 rotatably arranged in the shell 11, a first motor 13 for driving the packing rotor 12 to rotate, a liquid distributor 14 arranged in the middle of the packing rotor 12, a gas inlet 15 arranged on the side of the shell 11, a gas outlet arranged on the upper part of the shell 11, and a liquid outlet 17 arranged at the bottom of the shell 11.

[0070] In this embodiment, the high-gravity rotating adsorption bed 2 includes a housing 21, a rotating shaft 22 rotatably disposed within the housing 21, a rotor assembly 23 disposed on the rotating shaft 22, an air inlet 24 provided on the housing 21, and a second motor (not shown) for driving the rotating shaft 22. The rotating shaft 22 includes an upper rotating shaft portion 221 and a lower rotating shaft portion 222. The rotor assembly 23 is connected between the upper rotating shaft portion 221 and the lower rotating shaft portion 222. The rotor assembly 23 includes an upper rotor disk 231 connected to the bottom end of the upper rotating shaft portion 221, a lower rotor disk 232 connected to the upper end of the lower rotating shaft portion 222, and a plurality of rotor blades 233 of a wire mesh structure connected between the upper rotor disk 231 and the lower rotor disk 232 and arranged in an annular pattern. In this embodiment, twelve rotor blades 233 are included, with a pitch of 30° between the rotor blades 233 and radially uniform distribution. The rotor blades 233 are made of stainless steel wire mesh.

[0071] The upper rotating shaft portion 221 and the lower rotating shaft portion 222 are both rotatably connected to the housing 21 via bearings 25 , and the connection positions are sealed by sealing rings 26 to prevent gas leakage.

[0072] In this embodiment, the upper shaft portion 221 is hollow inside to form an exhaust channel 223 , the upper rotor disk 231 is provided with an exhaust through hole (not shown) communicating with the bottom of the exhaust channel 223 , and an exhaust port 224 is formed at the upper end of the exhaust channel 223 .

[0073] In this embodiment, the outlet end of the absorption liquid output pipeline 4 is connected to the bottom of the liquid distributor 14, the inlet end of the absorption liquid recovery pipeline 5 is connected to the liquid outlet 17 of the rotating packed bed 1, the inlet end of the gas delivery pipeline 7 is connected to the gas outlet at the upper end of the rotating packed bed 1, and the outlet end of the gas delivery pipeline 7 is connected to the air inlet 24 of the supergravity rotating adsorption bed 2.

[0074] The rotor blades 233 in the high-gravity rotating adsorption bed 2 are loaded with polyethylene glycol modified adsorbent fillers. The method for loading the polyethylene glycol modified adsorbent fillers on the rotor blades 233 is as follows:

[0075] Silica gel powder (particle size 60 mesh), polyethylene glycol, and silane coupling agent (specifically vinyltrichlorosilane) are mixed in a mass ratio of 100:40:1, and then a dispersant PVP is added (the addition amount is 6.5% of the total mass of the adsorbent powder, polyethylene glycol, and silane coupling agent). Ball milling is performed to obtain a uniform polyethylene glycol-modified adsorbent suspension. The rotor blade 233 (the blade surface is pre-acid-washed to increase the surface roughness) is immersed in the polyethylene glycol-modified adsorbent suspension for 10 minutes, slowly pulled to form a uniform wet film, and dried. The immersion, pulling, and drying operations are repeated three times to form a polyethylene glycol-modified adsorbent filler with a thickness of 130 μm on the rotor blade 233.

[0076] This embodiment also provides a texturing and etching tail gas treatment process in the production of a passivated back contact cell, which uses the above system to treat the texturing and etching tail gas. The process includes the following steps:

[0077] S1, add 10 tons of 30wt% sodium chlorite solution and 2 tons of 50wt% sulfuric acid solution to the absorption liquid storage container 3, mix them evenly to obtain oxidation absorption liquid, and 10000m 3 / h of texturing and etching exhaust gas (the main pollutant is NOx, containing a small amount of HF and sulfuric acid mist, of which the NOx concentration range is 400~430mg / m 3 , NO2 concentration range is 200~240mg / m 3 , NO concentration range is 180~210mg / m 3 HF concentration range is 8~10mg / m 3 ) is collected and then input into the rotating packed bed 1, and at the same time, the oxidizing absorption liquid in the absorption liquid storage container 3 is pumped into the rotating packed bed 1 at a flow rate of 100 L / h to react with the texturing etching tail gas, and the tail gas after the reaction is discharged and the oxidizing absorption liquid after the reaction is refluxed into the absorption liquid storage container 3 for recycling;

[0078] S2. The exhaust gas discharged from the rotating packed bed 1 enters the high-gravity rotating adsorption bed 2. The speed of the high-gravity rotating adsorption bed 2 is controlled to be 1200 rpm, and the high-gravity factor is 250. After the exhaust gas is purified by the polyethylene glycol-modified adsorbent filler on the rotor blade 233, it passes through the exhaust through-hole, the exhaust channel 223 and the exhaust port 224 in sequence and meets the emission standards.

[0079] After 40 days of continuous operation monitoring, the NOx concentration in the exhaust pipe was between 7 and 12 mg / m 3 Fluctuation within the range, HF concentration is 0.24~0.50mg / m 3 The concentration of sulfuric acid mist fluctuates within a certain range, and the concentration of sulfuric acid mist is between 0.3 and 2.8 mg / m 3 Fluctuates within a certain range, meeting the requirements of the Pollutant Emission Standard for Battery Industry (GB30484-2013).

[0080] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to specific details.

Claims

1. A texturing and etching tail gas treatment system in the production of passivated back contact cells, characterized in that: Including rotating packed bed, super gravity rotating adsorption bed and absorption liquid storage container: The rotor blades in the high-gravity rotating adsorption bed are loaded with polyethylene glycol modified adsorbent fillers, and the absorption liquid storage container is filled with oxidizing absorption liquid. The texturing and etching tail gas to be treated is first input into the rotating packed bed, and at the same time, the oxidizing absorption liquid in the absorption liquid storage container is pumped into the rotating packed bed to react with the texturing and etching tail gas. The tail gas after the reaction enters the high-gravity rotating adsorption bed, and is purified by the high-gravity rotating adsorption bed before being discharged in compliance with the emission standards. The method for loading the polyethylene glycol modified adsorbent filler on the rotor blades is as follows: The adsorbent powder, polyethylene glycol and silane coupling agent are mixed, and then a dispersant is added and ball milled to obtain a polyethylene glycol modified adsorbent suspension. The rotor blades are immersed in the polyethylene glycol modified adsorbent suspension, dried, and loaded on the rotor blades to form a polyethylene glycol modified adsorbent filler.

2. The texturing and etching tail gas treatment system in the production of passivated back contact cells according to claim 1 is characterized in that: The method for loading polyethylene glycol modified adsorbent filler on the rotor blade is: The adsorbent powder, polyethylene glycol, and silane coupling agent are mixed in a mass ratio of 100:20 to 40:1, and then a dispersant PVP is added and ball milled to obtain a uniform polyethylene glycol-modified adsorbent suspension. The rotor blade is immersed in the polyethylene glycol-modified adsorbent suspension for 5-20 minutes, pulled to form a uniform wet film, and dried. The immersion, pulling, and drying operations are repeated 2 to 3 times to form a polyethylene glycol-modified adsorbent filler with a thickness of 120 to 150 μm on the rotor blade.

3. The texturing and etching tail gas treatment system in the production of passivated back contact cells according to claim 2, characterized in that: The adsorbent powder is at least one of silica gel powder, graphite powder, activated carbon powder and zeolite powder.

4. The texturing and etching tail gas treatment system in the production of passivated back contact cells according to claim 3, characterized in that: The oxidation absorption liquid is a mixture of 20-40 wt% sodium chlorite solution and 30-70 wt% sulfuric acid solution in a mass ratio of 2.5-10:0.5-2.

5. The texturing and etching tail gas treatment system in the production of passivated back contact cells according to claim 1, characterized in that: The rotating packed bed includes a shell, a packing rotor rotatably arranged in the shell, a first motor for driving the packing rotor to rotate, a liquid distributor arranged in the middle of the packing rotor, a gas inlet arranged on the side of the shell, a gas outlet arranged on the upper part of the shell, and a liquid outlet arranged at the bottom of the shell.

6. The texturing and etching tail gas treatment system in the production of passivated back contact cells according to claim 5, characterized in that: The high-gravity rotating adsorption bed includes a shell, a rotating shaft rotatably arranged in the shell, a rotor assembly arranged on the rotating shaft, an air inlet opened on the shell, and a second motor for driving the rotating shaft to rotate.

7. The texturing and etching tail gas treatment system in the production of passivated back contact cells according to claim 6, characterized in that: The rotating shaft includes an upper rotating shaft portion and a lower rotating shaft portion, the rotor assembly is connected between the upper rotating shaft portion and the lower rotating shaft portion, the rotor assembly includes an upper rotor disk connected to the bottom end of the upper rotating shaft portion, a lower rotor disk connected to the upper end of the lower rotating shaft portion, and a plurality of rotor blades with a wire mesh structure connected between the upper rotor disk and the lower rotor disk and arranged in an annular shape; The upper rotating shaft portion is hollow inside to form an exhaust channel. The upper rotor disc is provided with an exhaust through hole connected to the bottom of the exhaust channel. The upper end of the exhaust channel forms an exhaust port.

8. The texturing and etching tail gas treatment system in the production of passivated back contact cells according to claim 7, characterized in that: The system also includes an absorption liquid output pipeline and an absorption liquid recovery pipeline connected to the absorption liquid storage container, a delivery pump arranged on the absorption liquid output pipeline, and a gas delivery pipeline connecting the rotating packed bed to the high-gravity rotating adsorption bed; The outlet end of the absorption liquid output pipeline is connected to the bottom of the liquid distributor, the inlet end of the absorption liquid recovery pipeline is connected to the liquid outlet of the rotating packed bed, the inlet end of the gas delivery pipeline is connected to the gas outlet at the upper end of the rotating packed bed, and the outlet end of the gas delivery pipeline is connected to the air inlet of the supergravity rotating adsorption bed.

9. A process for treating tail gas from texturing and etching in the production of passivated back contact cells, characterized in that: The system according to any one of claims 1 to 8 is used to treat the tail gas of texturing and etching, and the process includes the following steps: S1, inputting the texturing etching tail gas to be treated into a rotating packed bed, and at the same time pumping an oxidizing absorption liquid into the rotating packed bed to react with the texturing etching tail gas, the tail gas after the reaction is discharged, and the oxidizing absorption liquid after the reaction is refluxed into the absorption liquid storage container; S2. The exhaust gas discharged from the rotating packed bed enters the super gravity rotating adsorption bed and is purified by the super gravity rotating adsorption bed material before being discharged in compliance with the emission standards.

10. The process for treating tail gas from texturing and etching in the production of passivated back contact cells according to claim 9, characterized in that: The following steps are involved: S1. Add sodium chlorite solution and sulfuric acid solution to an absorption liquid storage container, mix them evenly to obtain an oxidizing absorption liquid, input the texturing etching tail gas to be treated into a rotating packed bed, and at the same time pump the oxidizing absorption liquid in the absorption liquid storage container into the rotating packed bed to react with the texturing etching tail gas, discharge the tail gas after the reaction, and reflux the oxidizing absorption liquid after the reaction into the absorption liquid storage container; S2. The exhaust gas discharged from the rotating packed bed enters the high-gravity rotating adsorption bed. The speed of the high-gravity rotating adsorption bed is controlled at 800-1200rpm and the high-gravity factor is 100-300. The exhaust gas is purified by the polyethylene glycol modified adsorbent filler on the rotor blades and then passes through the exhaust through-hole, exhaust channel and exhaust port in sequence to meet the emission standards.

Images