Photovoltaic industry high ammonia spraying wastewater treatment process

Abstract

The present application relates to a kind of photovoltaic industry high ammonia spray wastewater treatment process, process includes: (1) wastewater is adjusted to alkaline, make adjusted wastewater and air contact, ammonia nitrogen in wastewater is converted into ammonia gas, wherein, air temperature is greater than or equal to 40 ℃;(2) make the ammonia gas obtained in step (1) be absorbed by adsorbent, wherein, the preparation method of adsorbent is as follows: mixed solution is obtained by mixing iron-containing compound solution and carrier, then the mixed solution is suction filtered, and granular adsorbent is obtained by drying, carrier includes one or several combinations of active alumina, silicon oxide, zirconium oxide, magnesium oxide, molecular sieve.The photovoltaic industry high ammonia spray wastewater treatment process provided in the present application, under alkaline conditions, ammonia nitrogen in wastewater is converted into free ammonia, a large amount of air is effectively contacted with wastewater, ammonia is converted from liquid phase into gas phase, to achieve the purpose of removing ammonia nitrogen;The generated ammonia gas can enter the pores of adsorbent, the adsorption amount is large, and no by-product is produced.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment, specifically relating to a process for treating high-ammonia spray wastewater from the photovoltaic industry. Background Technology

[0002] In recent years, TOPCon batteries, the mainstream technology for next-generation solar cells, have ushered in new opportunities for industrialization and have begun large-scale applications. In the TOPCon battery production process, processes such as LPCVD, front-side coating, and back-side coating require the use of SiH4 and NH3 to treat silicon wafers. The resulting waste gas is typically treated using silane combustion towers, dust collectors, and spray towers, generating high-concentration ammonia nitrogen scrubbing wastewater. This type of wastewater has a single pollutant, high ammonia nitrogen concentration, and no organic pollutants. Conventional treatment technologies for this type of wastewater include biological denitrification, chemical precipitation, and stripping / vapor stripping, as detailed below:

[0003] Biological nitrogen removal: Ammonia nitrogen in wastewater is removed through a series of reactions such as nitrification and denitrification by various microorganisms, ultimately producing nitrogen gas. For wastewater with high biodegradability (B / C > 0.3), ammonia nitrogen can be removed biologically. When treating ammonia-containing wastewater biologically, the relative concentration of organic carbon is a major consideration, and maintaining the optimal carbon-to-nitrogen ratio is crucial for the success of biological treatment. Currently, common biological nitrogen removal processes can be divided into three categories: single-stage sludge systems, multi-stage sludge systems, and biofilm systems. In addition, there are newer nitrogen removal technologies such as short-cut nitrification / denitrification, simultaneous nitrification / denitrification, and anaerobic ammonia oxidation. Biological methods have the advantages of simple operation, stable performance, no secondary pollution, and economy. Disadvantages include large footprint, treatment efficiency being easily affected by temperature and toxic substances, and high requirements for operation and management. For high-concentration ammonia nitrogen spray wastewater generated by the photovoltaic industry, since the wastewater does not contain organic carbon, biological nitrogen removal requires the addition of a large amount of carbon source, resulting in extremely high operating costs.

[0004] Chemical precipitation: Chemical precipitation involves adding chemical agents to water to cause ammonia to react and form an insoluble precipitate, thus achieving nitrogen removal from wastewater. Commonly used chemicals are magnesium salts and soluble phosphates, which precipitate ammonia nitrogen and phosphorus in the wastewater as struvite (magnesium ammonium phosphate), while simultaneously recovering nitrogen and phosphorus from the wastewater. The ammonia nitrogen removal rate of chemical precipitation is generally 80%-90%, and the process is relatively simple with lower equipment investment. However, because it requires the addition of phosphates, whose discharge is strictly controlled by the state (the national first-class standard requires phosphorus <0.5 mg / L), subsequent phosphorus removal requirements are very high, and there is also the issue of downstream magnesium ammonium phosphate resource utilization.

[0005] Stripping / Stripping Method: Currently, the commonly used ammonia nitrogen stripping technology uses packed towers as stripping equipment. This method suffers from drawbacks such as large size, low efficiency, and high power consumption. During the ammonia nitrogen stripping process, scale forms inside the stripping tower, significantly reducing stripping efficiency and increasing power consumption. Furthermore, when treating high-concentration ammonia nitrogen wastewater using stripping methods in China, the stripped ammonia gas is absorbed by an absorbent to form ammonia water or ammonium sulfate. However, the absorption rate is generally low, and the recovered ammonia water or ammonium sulfate has a low concentration, resulting in low effective utilization. Therefore, stripping-absorption technology merely transfers ammonia from water to the air; the ammonia pollution problem is not properly addressed. Summary of the Invention

[0006] The purpose of this invention is to provide an improved process for treating high-ammonia spray wastewater in the photovoltaic industry, which removes ammonia nitrogen from the wastewater without generating byproducts.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A process for treating high-ammonia spray wastewater from the photovoltaic industry, the process comprising:

[0009] (1) Adjust the wastewater to alkaline, so that the adjusted wastewater comes into contact with air, and the ammonia nitrogen in the wastewater is converted into ammonia gas, wherein the air temperature is greater than or equal to 40℃;

[0010] (2) The ammonia gas obtained in step (1) is absorbed by the adsorbent, wherein the preparation method of the adsorbent is as follows: the iron-containing compound solution is mixed with the carrier to obtain a mixed solution, and then the mixed solution is filtered and dried to obtain a granular adsorbent. The carrier includes one or a combination of several of the following: activated alumina, silicon oxide, zirconium oxide, magnesium oxide, and molecular sieve.

[0011] Preferably, in step (2), the mass ratio of the carrier to the iron-containing compound solution is 1 g: (8-15) mL.

[0012] Preferably, in step (2), the concentration of the iron-containing compound solution is 5-20%.

[0013] Preferably, in step (2), the carrier is activated alumina, and the activated alumina has a particle size of 1-3 mm and a specific surface area of ​​300-350 m². 2 / g, Al2O3 content is greater than or equal to 93%.

[0014] Preferably, in step (1), the pH value of the wastewater is 9.5-10.5.

[0015] Preferably, the process is implemented using the following apparatus:

[0016] The device includes a first hypergravity reactor, which comprises:

[0017] A first housing, wherein an air outlet and a liquid outlet are provided on the first housing;

[0018] The first rotating shaft is partially disposed inside the first housing. The first rotating shaft extends along the vertical direction of the first housing, and the upper end and lower end of the first rotating shaft pass through the upper and lower parts of the first housing, respectively. The upper end of the first rotating shaft is provided with a liquid inlet channel, and the lower end of the first rotating shaft is provided with an air inlet channel.

[0019] A first rotor is mounted on a first rotating shaft. The first rotor has a reaction space for air to contact with wastewater. The upper and lower end faces of the first rotor have openings that communicate with the reaction space and allow air and wastewater to pass through. The liquid inlet channel communicates with the reaction space for supplying wastewater into the reaction space. The air inlet channel communicates with the reaction space for introducing air into the reaction space. The liquid outlet is also communicated with the reaction space.

[0020] A bushing is provided on the first rotating shaft located in the reaction space, and a flow space is formed between the bushing and the first rotating shaft. An opening communicating with the reaction space is provided on the bushing.

[0021] Preferably, in step (1), the hypergravity factor of the first hypergravity reactor is 80-100.

[0022] Preferably, the device further includes a second hypergravity reactor, the second hypergravity reactor comprising:

[0023] The second housing is provided with an air outlet;

[0024] The second rotating shaft is partially disposed within the second housing and extends vertically along the first housing, with one end of the second rotating shaft extending out of the second housing. An air inlet channel is provided on the second rotating shaft. The second rotor is disposed on the second rotating shaft and has a reaction space within it. The adsorbent is disposed within the reaction space. Both the upper and lower end faces of the second rotor have openings that communicate with the reaction space and allow ammonia gas to pass through. The air inlet channel communicates with the reaction space to introduce ammonia gas into the reaction space, and the air outlet communicates with the reaction space.

[0025] Preferably, in step (2), the hypergravity factor of the second hypergravity reactor is 50-70.

[0026] Preferably, the device further includes an air supply assembly, which includes a blower, a buffer tank, and a heater. The blower is connected to the buffer tank, the buffer tank is connected to the air inlet channel of the first rotating shaft, and the heater is disposed on the pipeline between the buffer tank and the first hypergravity reactor.

[0027] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0028] In the photovoltaic industry high-ammonia spray wastewater treatment process provided by this invention, under alkaline conditions, ammonia nitrogen in the wastewater is converted into free ammonia. A large amount of air is used to effectively contact the wastewater, causing the ammonia to transfer from the liquid phase to the gas phase, thereby achieving the purpose of removing ammonia nitrogen. The generated ammonia gas can enter the pores of the adsorbent, with a large adsorption capacity and no by-products are generated. Attached Figure Description

[0029] Appendix Figure 1 This is a schematic diagram of the apparatus used in the photovoltaic industry high-ammonia spray wastewater treatment process of the present invention.

[0030] Appendix Figure 2 This is a structural diagram of the first hypergravity reactor;

[0031] Appendix Figure 3 This is a structural diagram of the first rotating shaft of the first supergravity reactor;

[0032] Appendix Figure 4 This is a structural diagram of the second hypergravity reactor;

[0033] Appendix Figure 5 The graph shows the ammonia nitrogen removal rate of the first hypergravity reactor and the ammonia concentration at the outlet of the second hypergravity reactor in Example 1.

[0034] Appendix Figure 6 This is a graph showing the adsorption performance of the adsorbent for ammonia in Example 2.

[0035] In the attached diagrams above:

[0036] 1-First hypergravity reactor, 11-First shell, 111-Gas outlet, 112-Liquid outlet, 12-First rotating shaft, 121-Liquid inlet channel, 13-First rotor, 14-Shaft sleeve, 141-Opening;

[0037] 2-Second hypergravity reactor, 21-Second shell, 211-Outlet, 22-Second shaft, 221-Inlet channel, 23-Second rotor;

[0038] 3-Blower; 4-Buffer tank; 5-Heater; 6-First rotor flow meter; 7-First two-way valve; 8-Regulating tank; 9-Centrifugal pump; 10-Second rotor flow meter; 16-Second two-way valve; 17-First connector; 18-Second connector; 19-Third connector; 20-Air seal. Detailed Implementation

[0039] The present invention will be further described below with reference to the embodiments shown in the accompanying drawings.

[0040] A process for treating high-ammonia spray wastewater from the photovoltaic industry, comprising the following steps:

[0041] (1) Adjust the wastewater to alkaline (pH>7) so that the adjusted wastewater comes into contact with air and the ammonia nitrogen in the wastewater is converted into ammonia gas; wherein, the air has a certain temperature, the air temperature is greater than or equal to 40℃; the wastewater is high ammonia spray wastewater from the photovoltaic industry, the ammonia nitrogen concentration in the wastewater ranges from 1500-2500mg / L, the COD concentration is 0mg / L, the total nitrogen concentration ranges from 1500-2500mg / L, there is no nitrate nitrogen or organic nitrogen pollutants, and no heavy metal pollutants.

[0042] (2) The ammonia gas obtained in step (1) is absorbed by the adsorbent. The preparation method of the adsorbent is as follows: the iron-containing compound solution is mixed with the carrier to obtain a mixed solution, and then the mixed solution is filtered and dried to obtain a granular adsorbent.

[0043] The prepared adsorbent has both physical and chemical adsorption properties. Air passes through the adsorbent and undergoes adsorption mass transfer with it. Ammonia can enter the pores of the adsorbent, resulting in a large adsorption capacity.

[0044] In step (2), the support includes one or a combination of several of the following: activated alumina, silicon dioxide, zirconium oxide, magnesium oxide, and molecular sieves. Activated alumina is the optimal support, and it is purchased externally. The activated alumina has a particle size of 1-3 mm and a specific surface area of ​​330 μm. 2 / g, Al2O3 content ≥93%.

[0045] In step (2), the iron-containing compound includes one or a mixture of ferric chloride (FeCl3), ferrous chloride, ferric sulfate, ferrous sulfate, ferrous sulfide, ferric acetate, ferrous oxalate, ferric phosphate, ferric hydroxide, ferric hydroxide, ferric oxide, and magnetite. The concentration of the iron-containing compound solution is 5-20%, such as 8%, 12%, or 16%. The mass ratio of the carrier to the iron-containing compound solution is 1 g : (8-15) mL.

[0046] Iron-supported activated alumina is preferred because iron-modified activated alumina can achieve rapid magnetic separation of materials and increase the electrostatic adsorption capacity of the material surface, thereby increasing the amount of NH3 adsorbed.

[0047] In step (2), the drying temperature is 100℃-120℃.

[0048] To further understand the method of the present invention, the present invention further provides an apparatus for implementing the above-described method for removing nitrogen oxides from flue gas.

[0049] See Figures 1 to 4 The device includes a first hypergravity reactor 1 and a second hypergravity reactor 2. Hypergravity refers to an acceleration higher than Earth's gravitational acceleration (9.8 m / s²). 2 In a hypergravity environment, the forces (including gravitational or repulsive forces) experienced by matter are considered to be accelerations of approximately (10-1000) m / s². 2 The environment.

[0050] The first hypergravity reactor 1 is applied in step (1). The first hypergravity reactor 1 includes a first shell 11, a first rotating shaft 12, and a first rotor 13. The first shell 11 has a accommodating space and is provided with an air outlet 111 and a liquid outlet 112. The first rotating shaft 12 is partially disposed inside the first shell 11 and extends along the vertical direction of the first shell 11. The upper and lower ends of the first rotating shaft 12 extend out of the upper and lower parts of the first shell 11, respectively. The upper end of the first rotating shaft 12 is provided with a liquid inlet channel 121 for wastewater to enter, and the lower end of the first rotating shaft 12 is provided with an air inlet channel 221 for air to enter. Both the liquid inlet channel 121 and the air inlet channel 221 are located outside the first shell 11. In addition, the treated wastewater is discharged through the liquid outlet 112, and the generated ammonia gas is discharged through the air outlet 111.

[0051] The first rotor 13 is mounted on the first rotating shaft 12. The first rotor 13 is cylindrical and has a reaction space inside. The reaction space is used to allow air to come into contact with wastewater. The upper and lower end faces of the first rotor 13 both have openings that communicate with the reaction space and allow air and wastewater to pass through. The liquid inlet channel 121 is connected to the reaction space and is used to transport wastewater into the reaction space. The air inlet channel 221 is connected to the reaction space and is used to introduce air into the reaction space. The liquid outlet 112 is connected to the reaction space.

[0052] A bushing 14 is fitted over the first rotating shaft 12 located in the reaction space. The bushing 14 extends axially along the first rotating shaft 12, and a circulation space for air and wastewater is formed between the bushing 14 and the first rotating shaft 12. An opening 141 communicating with the reaction space is provided on the bushing 14. The bushing 14 is annular, and multiple openings 141 are provided on the outer peripheral wall of the bushing 14. The multiple openings 141 can be distributed along the vertical direction of the bushing 14.

[0053] The first supergravity reactor 1 also includes a first connector 17 and a second connector 18. The upper end of the first rotating shaft 12 is rotatably connected to the first connector 17 and the upper end of the first rotating shaft 12 is rotatably connected to the second connector 18. The first connector 17 has a channel communicating with the liquid inlet channel 121. Wastewater enters the first rotor 13 through the channel and the liquid inlet channel 121 of the first rotating shaft 12 in sequence. The second connector 18 has a channel communicating with the air inlet channel 221. Air enters the first rotor 13 through the channel and the air inlet channel 221 of the first rotating shaft 12 in sequence.

[0054] See Figure 3 The liquid inlet channel 121 at the upper end of the first rotating shaft 12 includes a first channel, a second channel, and a third channel that are connected to each other. The opening of the first channel is located at the upper end of the first rotating shaft 12, and the openings of the second and third channels are located on the outer peripheral side of the first rotating shaft 12 and are both located in the flow space between the first rotating shaft 12 and the bushing 14.

[0055] The air intake channel 221 at the lower end of the first rotating shaft 12 includes a first channel, a second channel, and a third channel that are connected to each other. The opening of the first channel is located at the lower end of the first rotating shaft 12, and the openings of the second and third channels are located on the outer periphery of the first rotating shaft 12, and are all located in the flow space between the first rotating shaft 12 and the bushing 14.

[0056] Furthermore, the reaction space of the first rotor 13 contains packing material, which is a regular stainless steel wire mesh, to increase the residence time of wastewater and air in the first rotor 13, making the reaction more thorough.

[0057] High ammonia nitrogen wastewater enters the flow space between the bushing 14 and the first rotating shaft 12 located inside the first rotor 13 through the liquid inlet channel 121 of the first rotating shaft 12. The high ammonia nitrogen wastewater is then evenly sprayed onto the inner edge of the packing inside the first rotor 13. Under the action of centrifugal force, it moves radially outward. The high ammonia nitrogen wastewater is sheared into micro-nano scale liquid forms such as liquid filaments, liquid droplets, and liquid films, providing a huge phase interface area for heat and mass transfer. In addition, the interface renewal rate is high, which greatly improves the rate of direct heat exchange between hot air and high ammonia wastewater in the rotating packing bed and the rate of ammonia desorption process. Free ammonia is rapidly transferred from the liquid phase to the gas phase and finally discharged from the ammonia outlet.

[0058] In this process, the ammonium ions (NH4+) in the high ammonia nitrogen wastewater + There is an equilibrium relationship between NH3 and free ammonia. This chemical equilibrium is related to pH and temperature. When pH > 7, increasing the pH, raising the temperature, or decreasing the partial pressure of ammonia in the gas phase will disrupt the equilibrium, shifting the reaction to the left and producing more free ammonia, which facilitates stripping. Under alkaline conditions, ammonia nitrogen in the wastewater is converted into free ammonia. A large amount of air (reducing the partial pressure of ammonia) is then used to effectively contact the wastewater in the rotating packing of the first supergravity reactor 1, causing ammonia to transfer from the liquid phase to the gas phase, thus achieving the purpose of removing ammonia nitrogen.

[0059] In step (1), the operating conditions of the first hypergravity reactor 1 are as follows: the pH value of the wastewater is 9.5-10.5, the gas-liquid ratio (the ratio of gas flow rate to liquid flow rate) is 500-1000, the hypergravity factor can be 80-100, and the air temperature can be 40-50℃.

[0060] Compared with traditional packed stripping towers, the first supergravity reactor 1 in step (1) has advantages such as small gas-liquid ratio, high removal efficiency, high gas-liquid mass transfer efficiency, and low energy consumption.

[0061] After treatment by the first supergravity reactor 1 in step (1), the ammonia nitrogen concentration in the wastewater is <300mg / L. After treatment by the A / O treatment system, the wastewater is discharged in compliance with the standards.

[0062] Furthermore, the device also includes an air supply assembly, which includes a blower 3, a buffer tank 4, and a heater 5. The blower 3 is connected to the buffer tank 4, and the buffer tank 4 is connected to the air inlet channel 221 of the first rotating shaft 12. The heater 5 is installed on the pipeline between the buffer tank 4 and the first hypergravity reactor 1. A first rotor flow meter 6 and a first two-way valve 7 are also installed on the pipeline between the buffer tank 4 and the heater 5. Air enters the buffer tank 4 through the blower 3, and after being regulated and controlled by the first rotor flow meter 6 and the valve, it enters the air heater 5. After being heated to a specified temperature, it enters the first hypergravity reactor 1, and the hot air passes through the packing material inside the first rotor.

[0063] Meanwhile, the device also includes a liquid delivery component, which includes an adjustment tank 8. The adjustment tank 8 is connected to the liquid inlet channel 121 of the first hypergravity reactor 1. A centrifugal pump 9, a second two-way valve 16, and a second rotor flow meter 10 are installed on the pipeline connecting the adjustment tank 8 and the first hypergravity reactor 1. The high ammonia spraying wastewater from the photovoltaic industry is regulated in the high ammonia nitrogen wastewater adjustment tank 8 to adjust the water quality and balance the water volume, and alkali is added to adjust the pH value to 10-11. Under the action of the centrifugal pump 9, after being regulated and controlled by the valve and the second rotor flow meter 10, it enters the first rotor 13 through the liquid inlet channel 121 of the first hypergravity reactor 1.

[0064] The device also includes a second hypergravity reactor 2, which includes a second shell 21, a second rotating shaft 22, and a second rotor 23. The second shell 21 has a accommodating space and an air outlet 211 is provided on the second shell 21. The second rotating shaft 22 is at least partially disposed inside the second shell 21. The second rotating shaft 22 extends along the vertical direction of the first shell 11, and one end of the second rotating shaft 22 extends out of the second shell 21. An air inlet channel 221 is provided on the end of the second rotating shaft 22 that extends out of the second shell 21. The air inlet channel 221 is located inside the second shell 21 and outside the second rotor 23.

[0065] The second rotor 23 is mounted on the second shaft 22. The second rotor 23 is cylindrical and has a reaction space inside. The reaction space contains an adsorbent. Both the upper and lower end faces of the second rotor 23 have openings that communicate with the reaction space and allow ammonia gas to pass through. The air inlet channel 221 is connected to the reaction space to introduce ammonia gas into the reaction space. The air outlet 211 is connected to the reaction space, and ammonia gas that is not absorbed by the adsorbent is discharged through the air outlet.

[0066] The device also includes a third connector 19, the lower end of the second rotating shaft 22 is rotatably connected to the third connector 19, the upper end of the second rotating shaft 22 is rotatably connected to the second rotor 23, and the third connector 19 is provided with a channel communicating with the inlet channel. Ammonia gas enters the reaction space of the second rotor 23 through the channel and the inlet channel 221 of the second rotating shaft 22 in sequence.

[0067] See Figure 4 The air intake passage 221 at the lower end of the second rotating shaft 22 includes a first passage, a second passage, and a third passage that are connected to each other. The opening of the first passage is located at the lower end of the second rotating shaft 22, and the openings of the second and third passages are located on the outer peripheral side of the second rotating shaft 22 and within the accommodating space of the second housing 21.

[0068] Both the first rotor 13 and the second rotor 23 are cylindrical. The reaction space of the second rotor 23 is equipped with a wire mesh, which can be used to place particulate adsorbents and fill them up. The filling amount can reach 200 kg.

[0069] Inside the second hypergravity reactor 2, the adsorbent particles are in a state of high-speed rotation, increasing the relative velocity with ammonia gas and thus increasing the probability of gas-solid two-phase contact. This increases the outward diffusion force of ammonia gas on the adsorbent surface, allowing more ammonia gas to come into contact with the adsorbent per unit time. Under the action of high-speed rotation, ammonia gas is rapidly renewed on the adsorbent surface, resulting in a high concentration of ammonia gas on the adsorbent surface. This effectively promotes the entry of ammonia gas into the adsorbent pores, increases the adsorption rate of the inner pores, promotes deep adsorption, and increases the adsorption capacity.

[0070] In this example, in step (1), the hypergravity factor of the first hypergravity reactor 1 is 80-100; in step (2), the hypergravity factor of the second hypergravity reactor 2 is 50-70.

[0071] The hypergravity factor is a dimensionless quantity used to measure the strength of a hypergravity field; it is the ratio of the rotor's average centrifugal acceleration to the acceleration under normal gravity. Its calculation formula is as follows:

[0072]

[0073] In the above formula, γ1 - inner radius (mm), γ2 - outer radius (mm), ω - angular velocity (rad / s), and g - gravitational acceleration 9.8 m / s². 2 .

[0074] The process of treating high-ammonia spray wastewater from the photovoltaic industry using the above-mentioned device is as follows:

[0075] In step (1), wastewater enters the flow space between the bushing 14 and the first rotating shaft 12 inside the first rotor 13 through the liquid inlet channel 121 of the first rotating shaft 12 of the first supergravity reactor 1, and then enters the reaction space of the first rotor 13; air enters the flow space between the bushing 14 and the first rotating shaft 12 inside the first rotor 13 through the air inlet channel 221 at the lower end of the first rotating shaft 12, and then enters the reaction space of the first rotor 13. The air and wastewater come into contact in the reaction space of the first rotor 13, causing ammonia to transfer from the liquid phase to the gas phase, and finally the ammonia gas is discharged through the gas outlet.

[0076] In step (2), the ammonia gas obtained in step (1) enters the reaction space of the second rotor 23 through the air inlet channel 221 of the second rotating shaft 22, and the ammonia gas is absorbed by the adsorbent in the reaction space of the second rotor 23.

[0077] The above-mentioned solution will be further described below with reference to specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments; the implementation conditions used in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0078] Example 1

[0079] At room temperature, a 16% (w / w) FeCl3 solution was prepared. A certain amount of activated alumina adsorbent material was weighed and added to the prepared FeCl3 solution, stirred for 2 hours, and then allowed to stand for 16 hours. After filtration and drying, the material was ready for use. The activated alumina was purchased externally, with a particle size of 1-3 mm and a specific surface area of ​​330 μm. 2 / g, Al2O3 content ≥93%, added in the ratio of activated alumina mass: FeCl3 solution volume = 1g: 10mL.

[0080] Airflow set to 200m 3 The solution is heated to 50°C per hour and then enters the first high-gravity reactor. Simultaneously, the NH3 in the high-ammonia spray wastewater from the photovoltaic industry... 4+ The concentration was 2500 mg / L, the pH was 10.5, and the liquid flow rate was set to 0.2-0.4 m³ / L. 3 The gas-liquid ratio (the ratio of gas flow rate to liquid flow rate) is 500-1000. Wastewater enters the reaction space of the first rotor through the liquid inlet of the first rotating shaft. Under the action of centrifugal force, it moves radially outward. The high ammonia nitrogen wastewater is sheared into micro-nano scale liquid forms such as liquid filaments, droplets, and liquid films, providing a huge phase interface area for heat and mass transfer. In addition, the high interface renewal rate greatly improves the rate of direct heat exchange between hot air and high ammonia wastewater in the rotating packed bed and the rate of ammonia desorption process. Free ammonia is rapidly transferred from the liquid phase to the gas phase and finally discharged from the ammonia outlet. The remaining low-concentration ammonia nitrogen wastewater is discharged from the liquid outlet at the lower end of the hypergravity system. The hypergravity factor β of the first hypergravity reactor is 100.

[0081] The reaction space of the second rotor in the second hypergravity reactor is lined with wire mesh, and the prepared ferric chloride-modified activated alumina adsorbent material is loaded into it, filling it completely with a loading amount of 200 kg. Ammonia gas discharged from the first hypergravity reactor is regulated and controlled by valves and a flow meter on the second rotor, with the gas flow rate set to 200 m³ / s. 3 / h, ammonia gas undergoes adsorption mass transfer with the adsorbent, and the hypergravity factor β of the second hypergravity reactor is 60.

[0082] In this example, the ammonia nitrogen removal rate and the ammonia concentration at the outlet of the first centrifugal reactor were obtained under different gas-liquid ratio conditions. Figure 5 ,Depend on Figure 5 It can be seen that the ammonia nitrogen removal rate increases with the increase of the gas-liquid ratio. This is because the increased gas-liquid ratio enhances the driving force for mass transfer between the gas and liquid phases, thereby accelerating the gas-liquid mass transfer rate of ammonia and thus improving the ammonia nitrogen removal rate. When the gas-liquid ratio is in the range of 500-1000, the ammonia nitrogen removal rate of the hypergravity ammonia removal system is higher than 85% (for the first hypergravity reactor, ammonia nitrogen removal rate = (NH4+ in inlet wastewater)). + Concentration - NH4 in residual wastewater at the outlet + (Concentration) / NH4 in inlet wastewater + (Concentration * 100%), the ammonia nitrogen concentration in the residual low-concentration ammonia nitrogen wastewater at the effluent outlet of the first hypergravity reactor is <300 mg / L, which can be treated in the biological system to meet discharge standards. The ammonia gas concentration at the effluent outlet of the second hypergravity reactor is 10 mg / m³. 3 Within this range, as the gas-liquid ratio increases, the ammonia concentration at the outlet gradually decreases, reaching a minimum of 3 mg / m³. 3 the following.

[0083] Example 2

[0084] At room temperature, a 12% (w / w) FeCl3 solution was prepared. A certain amount of activated alumina adsorbent material was weighed and added to the prepared FeCl3 solution, stirred for 2 hours, and then allowed to stand for 16 hours. After filtration and drying, the material was ready for use. The activated alumina was purchased externally, with a particle size of 1-3 mm and a specific surface area of ​​330 μm. 2 / g, Al2O3 content ≥93%, added in the ratio of activated alumina mass: FeCl3 solution volume = 1g: 10mL.

[0085] Airflow set to 200m 3 The solution is heated to 50°C per hour and then enters the first high-gravity reactor. Simultaneously, the NH3 in the high-ammonia spray wastewater from the photovoltaic industry... 4+ The concentration was 2000 mg / L, the pH was 10.5, and the liquid flow rate was set to 0.25 m³ / L. 3 / h, the gas-liquid ratio (the ratio of gas flow rate to liquid flow rate) is 800. Wastewater enters the reaction space of the first rotor through the liquid inlet of the first rotating shaft. Under the action of centrifugal force, it moves radially outward. The high ammonia nitrogen wastewater is sheared into micro-nano scale liquid forms such as liquid filaments, liquid droplets, and liquid films, providing a huge phase interface area for heat and mass transfer. In addition, the interface renewal rate is high, which greatly improves the rate of direct heat exchange between hot air and high ammonia wastewater in the rotating packed bed and the rate of ammonia desorption process. Free ammonia is rapidly transferred from the liquid phase to the gas phase and finally discharged from the ammonia gas outlet. The remaining low-concentration ammonia nitrogen wastewater is discharged from the liquid outlet at the lower end of the hypergravity system. The hypergravity factor β of the first hypergravity reactor is 100.

[0086] The reaction space of the second rotor in the second hypergravity reactor is lined with wire mesh, and the prepared ferric chloride-modified activated alumina adsorbent material is loaded into it, filling it completely with a loading amount of 200 kg. Ammonia gas discharged from the first hypergravity reactor is regulated and controlled by valves and a flow meter on the second rotor, with the gas flow rate set to 200 m³ / s. 3 / h, ammonia gas undergoes adsorption mass transfer with the adsorbent, and the hypergravity factor β of the second hypergravity reactor is 60.

[0087] In this example, the adsorption performance of the adsorbent material for ammonia was characterized by the adsorption curve of ammonia on the composite adsorbent material. The adsorption curve shows that after 50 days of operation, the ammonia concentration at the outlet of the second centrifugal reactor stabilized at 4 mg / m³. 3 Within this range, the NH3 adsorption capacity reaches 2.53 kg / kg adsorbent. This process system has the advantages of a long ammonia adsorption cycle and a large ammonia adsorption capacity. The adsorption curve is shown below. Figure 6 .

[0088] Experimental results

[0089] The elemental composition of the prepared adsorbent was quantitatively analyzed using inductively coupled plasma mass spectrometry (ICP). The amount of iron loaded on the surface of the activated alumina was determined by ICP testing, as shown in the table below:

[0090] Table 1. Data on the amount of iron loaded on the surface of activated alumina

[0091] Preparation conditions Fe element loading <![CDATA[FeCl3 solution with a mass concentration of 8%]]> 6.4％ <![CDATA[FeCl3 solution with a mass concentration of 12%]]> 9.52％ <![CDATA[FeCl3 solution with a mass concentration of 16%]]> 15.83％

[0092] The new and efficient treatment process for high-ammonia spray wastewater in the photovoltaic industry provided in this example can achieve a new and efficient treatment of high-ammonia spray wastewater in the photovoltaic industry. This process equipment has a small footprint, is easy to operate, has a high degree of controllability, produces no sludge, and can achieve clean wastewater treatment.

[0093] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A process for treatment of high ammonia spray wastewater from the photovoltaic industry, characterized in that, The process comprises: (1) adjusting the wastewater to be alkaline, and contacting the adjusted wastewater with air, so that the ammonia nitrogen in the wastewater is converted into ammonia gas, wherein the air temperature is 40-50℃, the gas-liquid ratio is 500-1000, and the pH value of the adjusted wastewater is 9.5-11; (2) absorbing the ammonia gas obtained in step (1) by an adsorbent, wherein the adsorbent is prepared by mixing a solution containing an iron compound with a carrier to obtain a mixed solution, and then performing suction filtration and drying on the mixed solution to obtain a granular adsorbent, and the carrier comprises one or a combination of several of active alumina, silicon oxide, zirconium oxide, magnesium oxide, and molecular sieve; The process is realized by the following device: The device comprises a first high gravity reactor, which comprises: a first shell, wherein a gas outlet and a liquid outlet are formed on the first shell; a first rotating shaft, which is partially arranged in the first shell, extends along the up-down direction of the first shell, and has an upper end and a lower end penetrating the upper part and the lower part of the first shell, respectively, wherein the upper end of the first rotating shaft is provided with a liquid inlet channel, and the lower end of the first rotating shaft is provided with an air inlet channel for air to enter, and high ammonia nitrogen wastewater enters the flow-through space between the shaft sleeve and the first rotating shaft located in the interior of the first rotor through the liquid inlet channel of the first rotating shaft; a first rotor, which is arranged on the first rotating shaft and has a reaction space in the interior thereof, wherein the reaction space is used for air and wastewater to contact, the upper and lower end faces of the first rotor are both provided with a port portion which is in communication with the reaction space and allows air and wastewater to pass through, the liquid inlet channel is in communication with the reaction space and is used for conveying wastewater into the reaction space, the air inlet channel is in communication with the reaction space and is used for introducing air into the reaction space, and the liquid outlet is in communication with the reaction space; the reaction space of the first rotor contains a filler, and the filler is a regular stainless steel wire mesh; a shaft sleeve is arranged on the first rotating shaft in the reaction space, and the shaft sleeve and the first rotating shaft form a flow-through space therebetween, and the shaft sleeve is provided with an opening which is in communication with the reaction space; The device further comprises a second high gravity reactor, which comprises: a second shell, wherein a gas outlet is arranged on the second shell; a second rotating shaft, which is partially arranged in the second shell, extends along the up-down direction of the second shell, and has one end penetrating the second shell, and is provided with an air inlet channel; a second rotor, which is arranged on the second rotating shaft and has a reaction space in the interior thereof, wherein the reaction space is provided with the adsorbent, the upper and lower end faces of the second rotor are both provided with a port portion which is in communication with the reaction space and allows ammonia gas to pass through, the air inlet channel is in communication with the reaction space and is used for introducing ammonia gas into the reaction space, and the gas outlet is in communication with the reaction space. The mass ratio of the carrier to the iron-containing compound solution in step (2) is 1g:(8-15)mL; the concentration of the iron-containing compound solution in step (2) is 5-20%; The high gravity factor of the first high gravity reactor in step (1) is 80-100; The high gravity factor of the second high gravity reactor in step (2) is 50-70; The device further comprises a blast assembly, which comprises a blower, a buffer tank and a heater, the blower is communicated with the buffer tank, the buffer tank is communicated with the air inlet channel of the first rotating shaft, and the heater is arranged on the pipeline between the buffer tank and the first high gravity reactor. A first rotor flowmeter and a first two-way valve are further arranged on the pipeline between the buffer tank and the heater.

2. The photovoltaic industry high ammonia spray wastewater treatment process of claim 1, wherein, In step (2), the carrier is activated alumina, the particle size diameter of the activated alumina is 1-3 mm, the specific surface area is 300-350 m 2 / g, and the Al2O3 content is greater than or equal to 93%.

3. The photovoltaic industry high ammonia spray wastewater treatment process of claim 1, wherein, The pH value of the wastewater in step (1) is 9.5-10.5.

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