Resourceful treatment system and process for oxidation and phosphorus diffusion tail gas in solar cell production process

Abstract

The invention discloses a resourceful treatment system and a resourceful treatment process for oxidation and phosphorus diffusion tail gas in a production process of a solar cell, and the resourceful treatment system adopts an efficient gas-liquid reactor, a supergravity solid-liquid reactor and a polymerization reactor as main reaction equipment, and uses a ferrous chloride solution generated by reaction of industrial hydrochloric acid and scrap iron as an absorption liquid; the method comprises the following steps: performing oxidation-reduction reaction on ferrous chloride and chlorine in the tail gas to generate an absorption reaction rich solution rich in ferric trichloride, and performing reduction regeneration on the absorption reaction rich solution through scrap iron to obtain a regeneration absorption solution rich in ferrous chloride for cyclic utilization to form a circulating system; when the concentration of the ferrous chloride solution in the regeneration absorption liquid rich in ferrous chloride reaches 45%-50%, part of the regeneration absorption liquid is fed into a polymerization reactor, a catalyst and a stabilizer are added, oxygen is introduced at the same time, catalytic oxidation is carried out on the regeneration absorption liquid, polymerization ferric chloride is generated, and resource utilization is achieved.

Description

Technical Field

[0001] The invention relates to the field of waste gas treatment, and in particular to a system and process for resource treatment of oxidation and phosphorus expansion tail gas in the production process of solar cell sheets. Background Art

[0002] Solar cells are made by doping semiconductors with different impurities to create P-type and N-type semiconductors. They are generally made of high-purity silicon wafers as the substrate and are produced through processes such as cleaning, texturing, phosphorus diffusion, deposition, printing, sintering, and packaging. Phosphorus diffusion is essentially the formation of a PN junction in silicon wafers, and phosphorus oxychloride is a diffusion source that is used more frequently for phosphorus diffusion. The silicon wafer is placed in a quartz container in a diffusion furnace. At a high temperature of 810 to 860°C, oxygen and phosphorus oxychloride react in the diffusion furnace as follows. The phosphorus atoms generated by the reaction diffuse into the silicon wafer, and the waste gas generated by the diffusion is mainly Cl2. Chlorine is a highly toxic substance, and its mass concentration in the air cannot exceed 1 mg / m 3 Otherwise, it will cause serious damage to the personnel and poisoning. And if the concentration in the air exceeds a certain range, it will cause serious explosion accidents and threaten the production safety of enterprises, so certain measures must be taken to deal with it.

[0003] At present, the treatment of chlorine mainly adopts the absorption principle, that is, the chlorine is absorbed by liquid alkali with a concentration of about 15%. This principle has certain production added value, but it also has certain defects. Chlorine has a certain range of solubility in water, so it is necessary to ensure that all treatments can be carried out through efficient planning to avoid incomplete absorption of chlorine and leakage. In addition, there is another principle that uses the oxidation and reduction of chlorine to prepare other industrial raw materials. However, this method has high system construction requirements, and also requires the joint action of some high temperature, high pressure or catalysts, and the corresponding cost investment is also large. Based on this, it is urgent to develop an efficient treatment process for the oxidation and phosphorus expansion tail gas generated in the production process of solar cells, so that the pollution factors in the tail gas meet the emission standards. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a system and process for resource processing of oxidation and phosphorus expansion tail gas in the production process of solar 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 process for resource treatment of oxidation and phosphorus expansion tail gas in the production process of solar cells is provided, and the process comprises the following steps:

[0006] S1, inputting fresh ferrous chloride solution into a high-efficiency gas-liquid reactor, filling a packing layer in a supergravity solid-liquid reactor, and loading scrap iron on the packing layer;

[0007] S2, injecting the regenerated ferrous chloride absorption liquid into the high-efficiency gas-liquid reactor through an ejector, mixing it with the fresh ferrous chloride solution to form an absorption liquid, and allowing the oxidation and phosphorus expansion tail gas to be treated, which is generated in the production process of solar cells, to enter the high-efficiency gas-liquid reactor, and react with the absorption liquid in the high-efficiency gas-liquid reactor to produce a gas-liquid mixing reaction, the chlorine in the tail gas oxidizes the ferrous chloride in the absorption liquid into ferric chloride, and the absorption reaction rich liquid is discharged from the bottom of the high-efficiency gas-liquid reactor, and the purified tail gas is discharged from the top of the high-efficiency gas-liquid reactor;

[0008] S3, the absorption reaction rich liquid enters the supergravity solid-liquid reactor through the liquid distributor, the supergravity solid-liquid reactor keeps rotating, the ferric chloride in the absorption reaction rich liquid is reduced to ferrous chloride, forming a regenerated ferrous chloride absorption liquid, which is discharged from the bottom of the supergravity solid-liquid reactor and then returned to the high-efficiency gas-liquid reactor;

[0009] S4. Monitor the concentration of ferrous chloride in the regenerated ferrous chloride absorption liquid. When the concentration reaches a set value, transport part of the regenerated ferrous chloride absorption liquid to the polymerization reactor to react with oxygen to form polyferric chloride.

[0010] Preferably, in step S1, the fresh ferrous chloride solution is obtained by reacting hydrochloric acid having a mass concentration of 20-35% with waste iron filings.

[0011] Preferably, in step S1, the mass concentration of ferrous chloride in the fresh ferrous chloride solution input into the high-efficiency gas-liquid reactor is controlled to be 0.5-2%.

[0012] Preferably, the packing layer in the supergravity solid-liquid reactor is a magnetic metal perforated plate corrugated regular packing layer.

[0013] Preferably, step S4 is specifically:

[0014] The concentration of ferrous chloride in the regenerated ferrous chloride absorption liquid is monitored. When the concentration reaches 45wt% to 50wt%, part of the regenerated ferrous chloride absorption liquid is transported to a polymerization reactor, and a catalyst and a stabilizer are added to the polymerization reactor. At the same time, oxygen is introduced to react the ferrous chloride with oxygen to generate polyferric chloride.

[0015] The second aspect of the present invention provides a system for resource processing of oxidation and phosphorus expansion tail gas generated in the production process of solar cells. The system uses the process as described above to process the oxidation and phosphorus expansion tail gas generated in the production process of solar cells. The system includes a high-efficiency gas-liquid reactor, a supergravity solid-liquid reactor and a polymerization reactor connected in sequence.

[0016] Preferably, the upper part of the high-efficiency gas-liquid reactor is provided with an ejector, a tail gas outlet and a fresh absorption liquid inlet, and the bottom of the high-efficiency gas-liquid reactor is provided with an absorption rich liquid outlet;

[0017] The ejector comprises a cylindrical tube section, a conical nozzle coaxially arranged in the cylindrical tube section, an air inlet pipe tangentially connected to the cylindrical tube section, a throat section connected to the cylindrical tube section, and a diffuser section connected to the throat section, wherein the opening on the cylindrical tube section forms an inlet end;

[0018] The regenerated ferrous chloride absorption liquid returned from the supergravity solid-liquid reactor enters the ejector from the inlet end of the column pipe section, so that negative pressure is generated in the column pipe section, thereby sucking the oxidation and phosphorus expansion tail gas generated in the production process of the solar cell into the ejector through the air inlet pipe, and entering the high-efficiency gas-liquid reactor together with the regenerated ferrous chloride absorption liquid after passing through the throat section and the diffusion pipe section.

[0019] Preferably, the absorption rich liquid outlet of the high-efficiency gas-liquid reactor is connected to the absorption rich liquid delivery pipe of the supergravity solid-liquid reactor, and the absorption rich liquid delivery pipe is provided with an absorption rich liquid temporary storage tank and an absorption rich liquid delivery pump;

[0020] A liquid distributor is fixedly inserted in the supergravity solid-liquid reactor, and the liquid distributor is connected to the end of the absorption rich liquid delivery pipe;

[0021] The ultra-gravity solid-liquid reactor is filled with a magnetic metal perforated plate corrugated regular packing layer, a plug hole for inserting the liquid distributor is opened in the middle of the packing layer, and the packing layer is arranged on the rotor of the ultra-gravity solid-liquid reactor.

[0022] Preferably, the liquid distributor comprises a shaft body arranged in a vertical direction and fixedly connected to the rotor of the supergravity solid-liquid reactor, a rotary joint rotatably connected to the shaft body, a sleeve sleeved on the shaft body, a liquid guide channel opened inside the upper end of the shaft body and connected to the lower end of the rotary joint, a liquid guide cavity formed between the inner wall of the sleeve and the outer wall of the shaft body, and a plurality of liquid outlet holes opened on the sleeve and connected to the liquid guide cavity; the end of the absorption rich liquid delivery pipe is connected to the rotary joint;

[0023] The liquid guiding channel comprises a vertical channel connected to the lower end of the rotary joint and a tapered channel connected to the lower end of the vertical channel, and the end of the tapered channel is connected to the liquid guiding cavity;

[0024] The liquid outlet holes include a first liquid outlet hole and a second liquid outlet hole. From the shaft body to the shaft sleeve, the diameter of the first liquid outlet hole gradually increases, and the diameter of the second liquid outlet hole gradually decreases. In the vertical direction, the first liquid outlet hole and the second liquid outlet hole are alternately arranged.

[0025] Preferably, a regeneration absorption liquid outlet is provided at the bottom of the supergravity solid-liquid reactor, a regeneration absorption liquid delivery pipe is connected to the supergravity solid-liquid reactor, and a regeneration absorption liquid delivery pump is provided on the regeneration absorption liquid delivery pipe;

[0026] The end of the regeneration absorption liquid delivery pipe is connected in parallel with a first branch pipe and a second branch pipe, the first branch pipe is connected to the inlet end of the ejector, and the second branch pipe is connected to the polymerization reactor;

[0027] The first branch pipe and the second branch pipe are respectively provided with a first solenoid valve and a second solenoid valve.

[0028] The beneficial effects of the present invention are:

[0029] Aiming at the emission characteristics of characteristic pollutants of oxidation and phosphorus expansion tail gas in the production process of solar cells, the present invention proposes a resource processing system and process of oxidation and phosphorus expansion tail gas in the production process of solar cells. The present invention adopts a high-efficiency gas-liquid reactor, a supergravity solid-liquid reactor and a polymerization reactor as main reaction equipment, utilizes ferrous chloride solution generated by the reaction of industrial hydrochloric acid and scrap iron as absorption liquid, and generates an oxidation-reduction reaction with chlorine in the tail gas to generate an absorption reaction rich liquid rich in ferric chloride, and the absorption reaction rich liquid is reduced and regenerated by scrap iron to obtain a regenerated absorption liquid rich in ferrous chloride for recycling, so as to form a circulation system; when the concentration of ferrous chloride solution in the regenerated absorption liquid rich in ferrous chloride reaches 45% to 50%, part of the regenerated absorption liquid is sent to the polymerization reactor, a catalyst and a stabilizer are added, and oxygen is introduced at the same time to catalytically oxidize the regenerated absorption liquid to generate polyferric chloride (PFC), so as to achieve resource utilization; polyferric chloride (PFC) is a novel inorganic polymer flocculant, which can be widely used in the fields of water supply and drainage.

[0030] The present invention not only realizes the treatment of oxidation and phosphorus expansion tail gas in the production process of solar cell sheets, but also can make full use of waste iron filings to realize the recycling of absorption liquid, and the absorption waste liquid can be used to prepare polyferric chloride (PFC), realizing the recycling of resources. The process of the present invention is simple and economical, and can not only achieve good environmental and social benefits, but also obtain good economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the structure of the oxidation and phosphorus expansion tail gas resource treatment system in the solar cell production process in Example 1 of the present invention;

[0032] Figure 2 is a schematic diagram of the structure of the ejector in Example 1 of the present invention;

[0033] Figure 3 It is a structural schematic diagram of the liquid distributor in Example 1 of the present invention;

[0034] Figure 4 It is an enlarged schematic diagram of the local structure of the liquid distributor in Example 1 of the present invention.

[0035] Description of reference numerals:

[0036] 1—high-efficiency gas-liquid reactor; 11—ejector; 12—exhaust outlet; 13—fresh absorption liquid inlet; 14—absorption rich liquid outlet; 111—column pipe section; 112—conical nozzle; 113—intake pipe; 114—throat section; 115—diffuser pipe section;

[0037] 2—supergravity solid-liquid reactor; 21—packing layer; 22—regeneration absorption liquid outlet; 23—regeneration absorption liquid delivery pipe; 24—regeneration absorption liquid delivery pump; 25—first branch pipe; 26—second branch pipe; 27—first solenoid valve; 28—second solenoid valve;

[0038] 3—polymerization reactor;

[0039] 4—absorption rich liquid delivery pipe; 41—absorption rich liquid temporary storage tank; 42—absorption rich liquid delivery pump; 411—vent pipe;

[0040] 5—liquid distributor; 51—shaft body; 52—rotating joint; 53—shaft sleeve; 54—liquid guide channel; 55—liquid guide cavity; 56—liquid outlet; 541—vertical channel; 542—conical channel; 561—first liquid outlet; 562—second liquid outlet. DETAILED DESCRIPTION

[0041] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0042] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0043] The test methods used in the following examples are conventional methods unless otherwise specified. The materials and reagents used in the following examples are all commercially available unless otherwise specified. In the following examples, if no specific conditions are specified, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used, if the manufacturer is not specified, are all conventional products that can be purchased commercially.

[0044] The present invention provides a process for resource processing of oxidation and phosphorus expansion tail gas in the production process of solar cell sheets, the process comprising the following steps:

[0045] S1, system preparation stage, industrial hydrochloric acid (30wt%) is used to react with scrap iron to generate fresh ferrous chloride solution, and then the fresh ferrous chloride solution is input into the high-efficiency gas-liquid reactor 1, and a packing layer 21 is filled in the supergravity solid-liquid reactor 2, and scrap iron is loaded on the packing layer 21;

[0046] S2, system startup stage, the regenerated ferrous chloride absorption liquid is injected into the high-efficiency gas-liquid reactor 1 through the injector 11, mixed with the fresh ferrous chloride solution to form an absorption liquid, and the oxidation and phosphorus expansion tail gas to be treated, which is generated in the production process of the solar cell, enters the high-efficiency gas-liquid reactor 1, and undergoes a gas-liquid mixing reaction with the absorption liquid in the high-efficiency gas-liquid reactor 1, the chlorine in the tail gas oxidizes the ferrous chloride in the absorption liquid into ferric chloride, the absorption reaction rich liquid is discharged from the bottom of the high-efficiency gas-liquid reactor 1, and the purified tail gas is discharged from the upper part of the high-efficiency gas-liquid reactor 1, and the discharge meets the standards;

[0047] S3, the absorption reaction rich liquid enters the supergravity solid-liquid reactor 2 through the liquid distributor 5, the supergravity solid-liquid reactor 2 keeps rotating, the ferric chloride in the absorption reaction rich liquid is reduced to ferrous chloride, forming a regenerated ferrous chloride absorption liquid, which is discharged from the bottom of the supergravity solid-liquid reactor 2 and then returned to the high-efficiency gas-liquid reactor 1;

[0048] S4, monitoring the concentration of ferrous chloride in the regenerated ferrous chloride absorption liquid, when the concentration reaches a set value, transporting part of the regenerated ferrous chloride absorption liquid to the polymerization reactor 3, and reacting with oxygen to form polyferric chloride.

[0049] In a preferred embodiment, in step S1, the mass concentration of ferrous chloride in the fresh ferrous chloride solution input into the high-efficiency gas-liquid reactor 1 is controlled to be 0.5-2%.

[0050] In a preferred embodiment, the packing layer 21 in the ultra-gravity solid-liquid reactor 2 has a magnetic metal perforated plate corrugated structured packing layer 21 .

[0051] In a preferred embodiment, step S4 is specifically as follows:

[0052] The concentration of ferrous chloride in the regenerated ferrous chloride absorption liquid is monitored. When the concentration reaches 45wt% to 50wt%, part of the regenerated ferrous chloride absorption liquid is transported to the polymerization reactor 3, and a catalyst and a stabilizer are added to the polymerization reactor 3. At the same time, oxygen is introduced to catalytically oxidize the ferrous chloride so that the ferrous chloride reacts with oxygen to form polyferric chloride (PFC).

[0053] The present invention also provides a resource processing system for oxidation and phosphorus expansion tail gas generated in the production process of solar cells. The system adopts the above process to process the oxidation and phosphorus expansion tail gas generated in the production process of solar cells. The system includes a high-efficiency gas-liquid reactor 1, a supergravity solid-liquid reactor 2 and a polymerization reactor 3 connected in sequence.

[0054] In a preferred embodiment, an ejector 11, a tail gas outlet 12 and a fresh absorption liquid inlet 13 are provided at the upper portion of the high-efficiency gas-liquid reactor 1, and an absorption rich liquid outlet 14 is provided at the bottom of the high-efficiency gas-liquid reactor 1;

[0055] The ejector 11 comprises a cylindrical tube section 111, a conical nozzle 112 coaxially arranged in the cylindrical tube section 111, an air inlet pipe 113 tangentially connected to the cylindrical tube section 111, a throat section 114 connected to the cylindrical tube section 111, and a diffuser section 115 connected to the throat section 114, wherein the opening on the cylindrical tube section 111 forms an inlet end;

[0056] The regenerated ferrous chloride absorption liquid returned from the supergravity solid-liquid reactor 2 enters the ejector 11 from the inlet end of the column pipe section 111, so that negative pressure is generated in the column pipe section 111, so that the oxidation and phosphorus expansion tail gas generated in the production process of the solar cell is sucked into the ejector 11 through the air inlet pipe 113, and enters the high-efficiency gas-liquid reactor 1 together with the regenerated ferrous chloride absorption liquid through the throat section 114 and the diffusion pipe section 115, and generates a gas-liquid mixing reaction with the absorption liquid.

[0057] In a preferred embodiment, the absorption rich liquid outlet 14 of the high-efficiency gas-liquid reactor 1 is connected to the absorption rich liquid delivery pipe 4 which is connected to the supergravity solid-liquid reactor 2, and the absorption rich liquid delivery pipe 4 is provided with an absorption rich liquid temporary storage tank 41 and an absorption rich liquid delivery pump 42; the absorption rich liquid temporary storage tank 41 is provided with a vent pipe 411;

[0058] A liquid distributor 5 is fixedly inserted in the supergravity solid-liquid reactor 2, and the liquid distributor 5 is connected to the end of the absorption rich liquid delivery pipe 4;

[0059] The ultra-gravity solid-liquid reactor 2 is filled with a magnetic metal perforated plate corrugated regular packing layer 21 , a plug hole for inserting the liquid distributor 5 is provided in the middle of the packing layer 21 , and the packing layer 21 is arranged on the rotor of the ultra-gravity solid-liquid reactor 2 .

[0060] The absorption reaction rich liquid enters the supergravity solid-liquid reactor 2 through the absorption reaction rich liquid delivery pump, and enters the internal packing layer 21 through the liquid distributor 5. The rotor drives the packing layer 21 to rotate at a certain speed. The strong shear force generated causes the absorption reaction rich liquid to be cut into liquid micro-elements, thereby increasing the contact area between the ferric chloride in the absorption reaction rich liquid and the scrap iron filings loaded on the packing, reducing the mass transfer diffusion resistance, and the ferric chloride is reduced to ferrous chloride. The regenerated absorption liquid is discharged from the bottom of the supergravity solid-liquid reactor 2 and re-enters the high-efficiency gas-liquid reactor 1 through the regenerated absorption liquid circulation pump for recycling.

[0061] In a preferred embodiment, the liquid distributor 5 includes a shaft body 51 arranged in a vertical direction and fixedly connected to the rotor of the supergravity solid-liquid reactor 2, a rotary joint 52 rotatably connected to the shaft body 51, a sleeve 53 sleeved on the shaft body 51, a liquid guide channel 54 opened inside the upper end of the shaft body 51 and connected to the lower end of the rotary joint 52, a liquid guide cavity 55 formed between the inner wall of the sleeve 53 and the outer wall of the shaft body 51, and a plurality of liquid outlet holes 56 opened on the sleeve 53 and connected to the liquid guide cavity 55; the end of the absorption rich liquid delivery pipe 4 is connected to the rotary joint 52;

[0062] The liquid guiding channel 54 includes a vertical channel 541 connected to the lower end of the rotary joint 52 and a tapered channel 542 connected to the lower end of the vertical channel 541, and the end of the tapered channel 542 is connected to the liquid guiding cavity 55;

[0063] The liquid outlet hole 56 includes a first liquid outlet hole 561 and a second liquid outlet hole 562. From the shaft body 51 to the shaft sleeve 53, the diameter of the first liquid outlet hole 561 gradually increases, and the diameter of the second liquid outlet hole 562 gradually decreases; along the vertical direction, the first liquid outlet hole 561 and the second liquid outlet hole 562 are arranged alternately.

[0064] The absorption reaction rich liquid passes through the rotary joint 52 and enters the vertical channel 541 of the liquid guide channel 54, and then is evenly distributed to the liquid guide cavity 55 through the tapered channel 542, and then discharged from the liquid distributor 5 through the liquid outlet hole 56 connected to the liquid guide cavity 55, so as to be evenly distributed outward to the packing layer 21. The liquid outlet holes 56 are arranged at intervals from top to bottom, so that the absorption reaction rich liquid can be more evenly discharged to various positions on the packing layer 21 in the vertical direction; and the outlet end of the first liquid outlet hole 561 is trumpet-shaped, which enables the discharged absorption reaction rich liquid to flow in the up and down directions in addition to flowing horizontally from the center to the outside, so that the absorption reaction rich liquid can be better dispersed to the packing layer 21 between adjacent liquid outlet holes 56, thereby strengthening the contact between the absorption reaction rich liquid and the packing layer 21 in the vertical direction; the outlet end of the second liquid outlet hole 562 is constricted, which enables the absorption reaction rich liquid to flow out in a jet-like shape, and the flow rate is increased, thereby strengthening the contact with the packing layer 21 in the horizontal direction; the first liquid outlet hole 561 and the second liquid outlet hole 562 are staggered in the vertical direction, so that the contact between the absorption reaction rich liquid and the packing layer 21 can be enhanced from the horizontal direction and the vertical direction, thereby improving the treatment effect of the ultra-gravity solid-liquid reactor 2.

[0065] In a preferred embodiment, a regeneration absorption liquid outlet 22 is provided at the bottom of the supergravity solid-liquid reactor 2, a regeneration absorption liquid delivery pipe 23 is connected to the supergravity solid-liquid reactor 2, and a regeneration absorption liquid delivery pump 24 is provided on the regeneration absorption liquid delivery pipe 23;

[0066] The end of the regeneration absorption liquid delivery pipe 23 is connected in parallel with a first branch pipe 25 and a second branch pipe 26. The first branch pipe 25 is connected to the inlet end of the ejector 11, and the second branch pipe 26 is connected to the polymerization reactor 3.

[0067] The first branch pipe 25 and the second branch pipe 26 are provided with a first solenoid valve 27 and a second solenoid valve 28 respectively. The first solenoid valve 27 and the second solenoid valve 28 can control the ratio of the regenerated ferrous chloride absorption liquid in the first branch pipe 25 and the second branch pipe 26.

[0068] The above is the overall concept of the present invention, and detailed embodiments and comparative examples are provided below on the basis of the overall concept of the present invention to further illustrate the present invention.

[0069] Example 1

[0070] A system for recycling oxidation and phosphorus expansion tail gas during the production of solar cell sheets comprises a high-efficiency gas-liquid reactor 1, a supergravity solid-liquid reactor 2 and a polymerization reactor 3 which are connected in sequence.

[0071] The upper part of the high-efficiency gas-liquid reactor 1 is provided with an ejector 11, a tail gas outlet 12 and a fresh absorption liquid inlet 13, and the bottom of the high-efficiency gas-liquid reactor 1 is provided with an absorption rich liquid outlet 14;

[0072] The ejector 11 comprises a cylindrical tube section 111, a conical nozzle 112 coaxially arranged in the cylindrical tube section 111, an air inlet pipe 113 tangentially connected to the cylindrical tube section 111, a throat section 114 connected to the cylindrical tube section 111, and a diffuser section 115 connected to the throat section 114, wherein the opening on the cylindrical tube section 111 forms an inlet end;

[0073] The regenerated ferrous chloride absorption liquid returned from the supergravity solid-liquid reactor 2 enters the ejector 11 from the inlet end of the column pipe section 111, so that negative pressure is generated in the column pipe section 111, so that the oxidation and phosphorus expansion tail gas generated in the production process of the solar cell is sucked into the ejector 11 through the air inlet pipe 113, and enters the high-efficiency gas-liquid reactor 1 together with the regenerated ferrous chloride absorption liquid through the throat section 114 and the diffusion pipe section 115, and generates a gas-liquid mixing reaction with the absorption liquid.

[0074] The absorption rich liquid outlet 14 of the high-efficiency gas-liquid reactor 1 is connected to the absorption rich liquid delivery pipe 4 of the supergravity solid-liquid reactor 2, and the absorption rich liquid delivery pipe 4 is provided with an absorption rich liquid temporary storage tank 41 and an absorption rich liquid delivery pump 42;

[0075] A liquid distributor 5 is fixedly inserted in the supergravity solid-liquid reactor 2, and the liquid distributor 5 is connected to the end of the absorption rich liquid delivery pipe 4;

[0076] The ultra-gravity solid-liquid reactor 2 is filled with a magnetic metal perforated plate corrugated regular packing layer 21 , a plug hole for inserting the liquid distributor 5 is provided in the middle of the packing layer 21 , and the packing layer 21 is arranged on the rotor of the ultra-gravity solid-liquid reactor 2 .

[0077] The absorption reaction rich liquid enters the supergravity solid-liquid reactor 2 through the absorption reaction rich liquid delivery pump, and enters the internal packing layer 21 through the liquid distributor 5. The rotor drives the packing layer 21 to rotate at a certain speed. The strong shear force generated causes the absorption reaction rich liquid to be cut into liquid micro-elements, thereby increasing the contact area between the ferric chloride in the absorption reaction rich liquid and the scrap iron filings loaded on the packing, reducing the mass transfer diffusion resistance, and the ferric chloride is reduced to ferrous chloride. The regenerated absorption liquid is discharged from the bottom of the supergravity solid-liquid reactor 2 and re-enters the high-efficiency gas-liquid reactor 1 through the regenerated absorption liquid circulation pump for recycling.

[0078] The liquid distributor 5 includes a shaft body 51 arranged in a vertical direction and fixedly connected to the rotor of the supergravity solid-liquid reactor 2, a rotary joint 52 rotatably connected to the shaft body 51, a sleeve 53 sleeved on the shaft body 51, a liquid guide channel 54 opened inside the upper end of the shaft body 51 and connected to the lower end of the rotary joint 52, a liquid guide cavity 55 formed between the inner wall of the sleeve 53 and the outer wall of the shaft body 51, and a plurality of liquid outlet holes 56 opened on the sleeve 53 and connected to the liquid guide cavity 55; the end of the absorption rich liquid delivery pipe 4 is connected to the rotary joint 52;

[0079] The liquid guiding channel 54 includes a vertical channel 541 connected to the lower end of the rotary joint 52 and a tapered channel 542 connected to the lower end of the vertical channel 541, and the end of the tapered channel 542 is connected to the liquid guiding cavity 55;

[0080] The liquid outlet hole 56 includes a first liquid outlet hole 561 and a second liquid outlet hole 562. From the shaft body 51 to the shaft sleeve 53, the diameter of the first liquid outlet hole 561 gradually increases, and the diameter of the second liquid outlet hole 562 gradually decreases; along the vertical direction, the first liquid outlet hole 561 and the second liquid outlet hole 562 are arranged alternately.

[0081] The bottom of the supergravity solid-liquid reactor 2 is provided with a regeneration absorption liquid outlet 22, the supergravity solid-liquid reactor 2 is connected with a regeneration absorption liquid delivery pipe 23, and the regeneration absorption liquid delivery pipe 23 is provided with a regeneration absorption liquid delivery pump 24;

[0082] The end of the regeneration absorption liquid delivery pipe 23 is connected in parallel with a first branch pipe 25 and a second branch pipe 26. The first branch pipe 25 is connected to the inlet end of the ejector 11, and the second branch pipe 26 is connected to the polymerization reactor 3.

[0083] The first branch pipe 25 and the second branch pipe 26 are provided with a first solenoid valve 27 and a second solenoid valve 28 respectively. The first solenoid valve 27 and the second solenoid valve 28 can control the ratio of the regenerated ferrous chloride absorption liquid in the first branch pipe 25 and the second branch pipe 26.

[0084] This embodiment also provides a process for resource recovery of oxidation and phosphorus expansion tail gas in the production process of solar cells, which uses the above system for treatment, and the process includes the following steps:

[0085] S1, system preparation stage, industrial hydrochloric acid (30wt%) is used to react with scrap iron to generate ferrous chloride solution, which is pumped into the high-efficiency gas-liquid reactor 1 as a fresh absorption liquid, and the initial ferrous chloride solution concentration is controlled to be 1%, and the initial dosage is 10t; at the same time, the supergravity solid-liquid reactor 2 is filled with a magnetic metal perforated plate corrugated regular packing layer 21, and the packing layer 21 is loaded with scrap iron, and the load is 200 kg.

[0086] S2, system startup stage, regenerated ferrous chloride absorption liquid through the first branch pipe 25 with a flow rate of 0.05m 3 / h is injected into the high-efficiency gas-liquid reactor 1 from the ejector 11 at the top, so that a certain negative pressure is generated inside the column pipe section 111 of the ejector 11, and the oxidation and phosphorus expansion tail gas (tail gas volume 400m 3 / h, chlorine concentration 90~100mg / m 3) is sucked into the high-efficiency gas-liquid reactor 1, and reacts with the absorption liquid to produce a gas-liquid mixed reaction. The chlorine in the tail gas oxidizes the ferrous chloride in the absorption liquid into ferric chloride. The absorption reaction rich liquid enters the absorption reaction rich liquid temporary storage tank from the bottom of the high-efficiency gas-liquid reactor 1. The oxidized and phosphorus-expanded tail gas is purified and discharged from the upper outlet of the high-efficiency gas-liquid reactor 1 into the exhaust pipe. The chlorine concentration in the tail gas at the monitoring port of the exhaust pipe is less than 5mg / m 3 , meet the emission requirements of the "Battery Industry Pollutant Emission Standard" (GB30484-2013) and meet the emission standards.

[0087] S3, the absorption reaction rich liquid is transported by the absorption reaction rich liquid delivery pump at a flow rate of 0.05m 3 / h enters the supergravity solid-liquid reactor 2, enters the internal packing layer 21 through the liquid distributor 5, and the rotor drives the packing layer 21 to rotate at a certain speed. The strong shear force generated causes the absorption reaction rich liquid to be cut into liquid micro-elements, thereby increasing the contact area between the ferric chloride in the absorption reaction rich liquid and the scrap iron filings loaded on the packing, reducing the mass transfer diffusion resistance, and the ferric chloride is reduced to ferrous chloride. The regenerated absorption liquid is discharged from the bottom of the supergravity solid-liquid reactor 2 and re-enters the high-efficiency gas-liquid reactor 1 through the regenerated absorption liquid circulation pump for recycling.

[0088] S4. Monitor the concentration of ferrous chloride in the regenerated absorption liquid. When the concentration of ferrous chloride reaches 45%, a part (the specific flow rate of this part accounts for 80%) of the regenerated absorption liquid is sent into the polymerization reactor 3 through the second branch pipe 26, and a catalyst (specifically a nitrite solution, the addition amount is 4.5% of the mass of ferrous chloride) and a stabilizer (specifically a phosphate, the addition amount is 3.5% of the mass of ferrous chloride) are added, and oxygen is introduced at the same time to catalyze and oxidize it to generate polyferric chloride (PFC).

[0089] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. 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 process for recycling oxidation and phosphorus expansion tail gas in the production process of solar cells, characterized in that: The process includes the following steps: S1, inputting fresh ferrous chloride solution into a high-efficiency gas-liquid reactor, filling a packing layer in a supergravity solid-liquid reactor, and loading scrap iron on the packing layer; S2, injecting the regenerated ferrous chloride absorption liquid into the high-efficiency gas-liquid reactor through an ejector, mixing it with the fresh ferrous chloride solution to form an absorption liquid, and allowing the oxidation and phosphorus expansion tail gas to be treated, which is generated in the production process of solar cells, to enter the high-efficiency gas-liquid reactor, and react with the absorption liquid in the high-efficiency gas-liquid reactor to produce a gas-liquid mixing reaction, the chlorine in the tail gas oxidizes the ferrous chloride in the absorption liquid into ferric chloride, and the absorption reaction rich liquid is discharged from the bottom of the high-efficiency gas-liquid reactor, and the purified tail gas is discharged from the top of the high-efficiency gas-liquid reactor; S3, the absorption reaction rich liquid enters the supergravity solid-liquid reactor through the liquid distributor, the supergravity solid-liquid reactor keeps rotating, the ferric chloride in the absorption reaction rich liquid is reduced to ferrous chloride, forming a regenerated ferrous chloride absorption liquid, which is discharged from the bottom of the supergravity solid-liquid reactor and then returned to the high-efficiency gas-liquid reactor; S4. Monitor the concentration of ferrous chloride in the regenerated ferrous chloride absorption liquid. When the concentration reaches a set value, transport part of the regenerated ferrous chloride absorption liquid to the polymerization reactor to react with oxygen to form polyferric chloride.

2. The process for recycling oxidation and phosphorus expansion tail gas in the production process of solar cells according to claim 1, characterized in that: In step S1, fresh ferrous chloride solution is obtained by reacting hydrochloric acid with a mass concentration of 20-35% with waste iron filings.

3. The process for recycling oxidation and phosphorus expansion tail gas in the production process of solar cells according to claim 2, characterized in that: In step S1, the mass concentration of ferrous chloride in the fresh ferrous chloride solution input into the high-efficiency gas-liquid reactor is controlled to be 0.5-2%.

4. The process for recycling oxidation and phosphorus expansion tail gas in the production process of solar cells according to claim 1, characterized in that: The packing layer in the supergravity solid-liquid reactor is a corrugated regular packing layer of a metal perforated plate with magnetism.

5. The process for recycling oxidation and phosphorus expansion tail gas in the production process of solar cells according to claim 1, characterized in that: Step S4 is specifically as follows: The concentration of ferrous chloride in the regenerated ferrous chloride absorption liquid is monitored. When the concentration reaches 45wt% to 50wt%, part of the regenerated ferrous chloride absorption liquid is transported to a polymerization reactor, and a catalyst and a stabilizer are added to the polymerization reactor. At the same time, oxygen is introduced to react the ferrous chloride with oxygen to generate polyferric chloride.

6. A system for recycling oxidation and phosphorus expansion tail gas in the production process of solar cells, characterized in that: The system uses the process described in any one of claims 1 to 5 to treat the oxidation and phosphorus expansion tail gas generated during the production of solar cells. The system includes a high-efficiency gas-liquid reactor, a supergravity solid-liquid reactor and a polymerization reactor connected in sequence.

7. The system for recycling oxidation and phosphorus expansion tail gas in the production process of solar cells according to claim 6, characterized in that: The upper part of the high-efficiency gas-liquid reactor is provided with an ejector, a tail gas outlet and a fresh absorption liquid inlet, and the bottom of the high-efficiency gas-liquid reactor is provided with an absorption rich liquid outlet; The ejector comprises a cylindrical tube section, a conical nozzle coaxially arranged in the cylindrical tube section, an air inlet pipe tangentially connected to the cylindrical tube section, a throat section connected to the cylindrical tube section, and a diffuser section connected to the throat section, wherein the opening on the cylindrical tube section forms an inlet end; The regenerated ferrous chloride absorption liquid returned from the supergravity solid-liquid reactor enters the ejector from the inlet end of the column pipe section, so that negative pressure is generated in the column pipe section, thereby sucking the oxidation and phosphorus expansion tail gas generated in the production process of the solar cell into the ejector through the air inlet pipe, and entering the high-efficiency gas-liquid reactor together with the regenerated ferrous chloride absorption liquid after passing through the throat section and the diffusion pipe section.

8. The system for recycling oxidation and phosphorus expansion tail gas in the production process of solar cells according to claim 7, characterized in that: The absorption rich liquid outlet of the high-efficiency gas-liquid reactor is connected to an absorption rich liquid delivery pipe connected to the supergravity solid-liquid reactor, and the absorption rich liquid delivery pipe is provided with an absorption rich liquid temporary storage tank and an absorption rich liquid delivery pump; A liquid distributor is fixedly inserted in the supergravity solid-liquid reactor, and the liquid distributor is connected to the end of the absorption rich liquid delivery pipe; The ultra-gravity solid-liquid reactor is filled with a magnetic metal perforated plate corrugated regular packing layer, a plug hole for inserting the liquid distributor is opened in the middle of the packing layer, and the packing layer is arranged on the rotor of the ultra-gravity solid-liquid reactor.

9. The system for recycling oxidation and phosphorus expansion tail gas in the production process of solar cells according to claim 8, characterized in that: The liquid distributor comprises a shaft body arranged in a vertical direction and fixedly connected to the rotor of the supergravity solid-liquid reactor, a rotary joint rotatably connected to the shaft body, a sleeve sleeved on the shaft body, a liquid guide channel opened inside the upper end of the shaft body and connected to the lower end of the rotary joint, a liquid guide cavity formed between the inner wall of the sleeve and the outer wall of the shaft body, and a plurality of liquid outlet holes opened on the sleeve and connected to the liquid guide cavity; the end of the absorption rich liquid delivery pipe is connected to the rotary joint; The liquid guiding channel comprises a vertical channel connected to the lower end of the rotary joint and a tapered channel connected to the lower end of the vertical channel, and the end of the tapered channel is connected to the liquid guiding cavity; The liquid outlet holes include a first liquid outlet hole and a second liquid outlet hole. From the shaft body to the shaft sleeve, the diameter of the first liquid outlet hole gradually increases, and the diameter of the second liquid outlet hole gradually decreases. In the vertical direction, the first liquid outlet hole and the second liquid outlet hole are alternately arranged.

10. The system for recycling oxidation and phosphorus expansion tail gas in the production process of solar cells according to claim 9, characterized in that: The bottom of the supergravity solid-liquid reactor is provided with a regeneration absorption liquid outlet, the supergravity solid-liquid reactor is connected with a regeneration absorption liquid delivery pipe, and the regeneration absorption liquid delivery pipe is provided with a regeneration absorption liquid delivery pump; The end of the regeneration absorption liquid delivery pipe is connected in parallel with a first branch pipe and a second branch pipe, the first branch pipe is connected to the inlet end of the ejector, and the second branch pipe is connected to the polymerization reactor; The first branch pipe and the second branch pipe are respectively provided with a first solenoid valve and a second solenoid valve.

Images