Mixed type dry desulfurization and denitrification process

Abstract

The invention discloses a mixed type dry desulfurization and denitrification process, which relates to the technical field of desulfurization and denitrification, and comprises the following steps: S1, spraying ammonia water into an inner cavity of a boiler through a spray gun, and removing part of NOX in flue gas by adopting an SNCR (selective non-catalytic reduction) denitrification process; s2, partially denitrified flue gas enters a desulfurizing agent bin to be subjected to desulfurization treatment; s3, the desulfurized flue gas is subjected to dust removal through a dust remover; s4, under pressurized adsorption of a booster fan, the dedusted gas enters an SCR reactor to be subjected to catalytic reduction and denitration again, and the denitrated gas is discharged through a chimney; and S5, performing unified treatment on the dust after dust removal. By means of the arrangement mode that the pretreatment unit, the SCR reactor, the desulfurization unit and the dust removal unit are matched, flue gas is subjected to SNCR non-catalytic reduction denitration, sulfur dioxide in the flue gas can be removed through the desulfurization unit, finally desulfurization products and dust in the flue gas are removed through the dust removal unit, and the treated flue gas returns to a boiler chimney to be discharged after reaching the standard.

Description

Technical Field

[0001] The present invention relates to the technical field of desulfurization and denitrification, and in particular to a mixed dry desulfurization and denitrification process. Background Art

[0002] With the development of industry and the improvement of people's living standards, the thirst for energy is also increasing. SO2 in coal-fired flue gas has become the main cause of air pollution. Reducing SO2 pollution has become a top priority for today's atmospheric environmental governance. Many flue gas desulfurization processes have been widely used in industry, and desulfurization generally refers to the removal of sulfur from fuel before combustion and the desulfurization process before flue gas emission. It is one of the important technical measures to prevent and control air pollution. It also has important practical significance for the treatment of exhaust gases from various boilers and incinerators.

[0003] In order to prevent excessive NOx pollution from being produced after coal combustion in boilers, coal should be denitrated. Denitrification is divided into denitrification before combustion, denitrification during combustion, and denitrification after combustion. There are generally three desulfurization methods: desulfurization before combustion, desulfurization during combustion, and desulfurization after combustion. Summary of the invention

[0004] The object of the present invention is to provide a hybrid dry desulfurization and denitrification process to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a hybrid dry desulfurization and denitrification process, comprising the following steps:

[0006] S1. Spray ammonia water into the boiler cavity through a spray gun, and use SNCR non-catalytic reduction denitrification process to remove part of NO in the flue gas. X ;

[0007] S2. The partially denitrated flue gas enters the desulfurizer bin for desulfurization treatment under the suction of the induced draft fan;

[0008] S3, the flue gas after desulfurization is dedusted by a dust collector;

[0009] S4. Under the pressure adsorption of the booster fan, the gas after dust removal enters the SCR reactor for catalytic reduction and denitrification again, and the denitrified gas is discharged through the chimney;

[0010] S5. The dust after dust removal is uniformly processed through the dust storage bin;

[0011] The hybrid dry desulfurization and denitrification process adopts a hybrid dry desulfurization and denitrification device comprising:

[0012] A boiler, wherein the combustion material of the boiler is particulate matter;

[0013] A pretreatment unit, wherein the pretreatment unit is installed on the boiler;

[0014] An SCR reactor, wherein the SCR reactor is used for denitration of flue gas;

[0015] A chimney, wherein the chimney is installed at the gas outlet end of the SCR reactor;

[0016] An induced draft fan, which is used to induce negative pressure air flow in the flue gas in the boiler through an air duct;

[0017] A desulfurization unit, wherein the desulfurization unit is installed at one end of the air outlet of the induced draft fan through a pipeline;

[0018] A dust removal unit and a booster fan, wherein the dust removal unit is installed between the desulfurization unit and the booster fan.

[0019] Preferably, the pretreatment unit includes: an autonomous compressed air system, an ammonia water supply unit and a reflux valve, the ammonia water supply unit sprays ammonia water into the inner cavity of the boiler through a spray gun, the autonomous compressed air system is used for gas supply to the spray gun, the reflux valve is installed in the reflux section of the flue gas, and the reflux valve is in a normally closed state.

[0020] Preferably, the ammonia water supply unit comprises: an ammonia water tank and an ammonia water pump, wherein the ammonia water pump is installed at the water outlet end of the ammonia water tank, and the ammonia water pump is used to supply water in the inner cavity of the ammonia water tank to the inner cavity of the spray gun.

[0021] Preferably, the desulfurization unit comprises:

[0022] A desulfurization agent bin, which is used for desulfurization of flue gas;

[0023] A first silo top dust removal box, wherein the first silo top dust removal box is installed on the top of the desulfurizer silo;

[0024] A first rapping motor, wherein the first rapping motor is fixed to the bottom of the desulfurizing agent bin;

[0025] A first star-shaped discharger, wherein the first star-shaped discharger is installed at the bottom of the desulfurizing agent bin;

[0026] A metering conveyor, which is installed at the discharge end of the first star-shaped discharger;

[0027] An electric heater, wherein the electric heater is arranged at the air inlet end of the metering conveyor;

[0028] a first Roots blower and a second Roots blower, wherein the first Roots blower and the second Roots blower are installed at one end of the electric heater through a pipeline;

[0029] A compressed air storage tank is connected to the first silo top dust removal box through an air supply duct.

[0030] Preferably, the first Roots blower and the second Roots blower are connected to the dust removal unit via a pipeline, and the compressed air storage tank is connected to the dust removal unit via an air supply pipeline.

[0031] Preferably, the dust removal unit comprises:

[0032] A dust collector, one end of which is connected to the air inlet duct of the booster fan through a non-metallic expansion joint;

[0033] An ash hopper, which is installed at the bottom of the dust collector;

[0034] The second star-shaped discharger is installed at the bottom of the ash hopper.

[0035] Preferably, the other end of the dust collector is connected to the air outlet pipe of the induced draft fan through a non-metallic expansion joint.

[0036] Preferably, the second star-shaped discharger is provided with an ash storage unit via a discharge pipe, and the air outlet end of the booster fan is connected to the chimney via an SCR reactor.

[0037] Preferably, the ash storage unit comprises:

[0038] An ash storage bin connected to the second star-shaped discharger via a discharge pipe;

[0039] A second silo top dust removal box, wherein the second silo top dust removal box is installed on the top of the ash storage silo;

[0040] A second rapping motor, wherein the second rapping motor is installed at the bottom of the ash storage bin;

[0041] A discharge hopper, which is installed at the bottom of the ash storage bin and is used to discharge the ash in the ash storage bin;

[0042] A Roots vacuum pump is connected to the top of the second silo top dust removal box through a vacuum pipeline.

[0043] Preferably, the second silo top dust removal box is connected to the air outlet pipe of the compressed air storage tank through a pipeline.

[0044] Technical effects and advantages of the present invention:

[0045] (1) The present invention adopts a configuration mode in which a pretreatment unit, an SCR reactor, a desulfurization unit and a dust removal unit are coordinated. The flue gas passes through the pretreatment unit for SNCR non-catalytic reduction denitrification, the desulfurization unit can remove sulfur dioxide in the flue gas, and finally the desulfurization products and dust in the flue gas are removed by the dust removal unit. The treated flue gas returns to the boiler chimney to meet the emission standards;

[0046] (2) The present invention adopts a configuration mode in which the desulfurization unit and the dust removal unit are matched to each other, so that the flue gas passes through the SCR reactor for dust removal, so that the catalyst micropores in the SCR reactor will not be blocked by dust, and the activity of the catalyst is maintained, so that the SCR reactor can stably denitrate the flue gas, and the denitration system can operate more stably, reliably and efficiently;

[0047] (3) The present invention adopts a configuration in which the induced draft fan and the booster fan are coordinated so that the desulfurization unit, the dust removal unit and the SCR reactor can perform stable desulfurization and denitrification. The process is simple, there is no problem of sewage and waste acid treatment, the energy consumption is low, the temperature of the flue gas after purification is high, which is conducive to the diffusion of chimney exhaust gas and does not produce white smoke. The corrosiveness of the purified flue gas is low, and the environmental protection performance is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0049] Figure 2 It is a schematic diagram of the structure of the boiler of the present invention.

[0050] Figure 3 It is a schematic diagram of the structure of the pre-treatment part of the present invention.

[0051] Figure 4 It is a structural schematic diagram of the ammonia water tank of the present invention.

[0052] Figure 5 It is a structural schematic diagram of the desulfurizer bin of the present invention.

[0053] Figure 6 It is a schematic diagram of the structure of the dust collector of the present invention.

[0054] Figure 7 It is a structural schematic diagram of the ash storage bin of the present invention.

[0055] In the figure: 1. Boiler; 2. Pretreatment unit; 21. In-house compressed air system; 22. Ammonia supply unit; 2201. Ammonia tank; 2202. Ammonia pump; 23. Reflux valve; 3. SCR reactor; 4. Chimney; 5. Draft fan; 6. Desulfurization unit; 61. Desulfurization agent bin; 62. First bin top dust removal box; 63. First vibrating motor; 64. First star-shaped discharger; 65. Measuring conveyor; 66. Electric heater; 67. First Roots blower; 68. Second Roots blower; 69. Compressed air storage tank; 7. Dust removal unit; 71. Dust collector; 72. Ash hopper; 73. Second star-shaped discharger; 8. Booster fan; 9. Ash storage unit; 91. Ash storage bin; 92. Second bin top dust removal box; 93. Second vibrating motor; 94. Discharge hopper; 95. Roots vacuum pump. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] The present invention provides Figure 1-7 A hybrid dry desulfurization and denitrification process shown includes the following steps:

[0058] S1, spray ammonia water into the inner cavity of boiler 1 through a spray gun, and use SNCR non-catalytic reduction denitrification process to remove part of NO in the flue gas X , ammonia water is evenly sprayed into boiler 1 using a spray gun. The temperature range of boiler 1 is 850℃ to 1250℃. NOX in flue gas is selectively reduced to N2 and H2O, thereby achieving the purpose of denitrification. The chemical reaction equation is as follows:

[0059] 4NH3+5O2→4NO+6H2O;

[0060] S2. The partially denitrified flue gas enters the desulfurization agent bin 61 under the suction of the induced draft fan 5 for desulfurization treatment, wherein the desulfurization agent loaded in the desulfurization agent bin 61 is active calcium, and the active calcium is used to replenish the desulfurization agent in the desulfurization agent bin 61 in real time through the loading vehicle. The principle of active calcium desulfurization is mainly based on the chemical reaction between active calcium and sulfur dioxide in the flue gas. When the active calcium contacts the flue gas, the alkaline oxide on its surface reacts with sulfur dioxide to generate calcium sulfate or other forms of sulfur compounds. This reaction process usually needs to be carried out under certain temperature and humidity conditions to ensure the adequacy and efficiency of the reaction. The use of active calcium desulfurization technology can effectively reduce the emission concentration of sulfur dioxide in the flue gas and protect the atmospheric environment; the reaction of the active calcium with sulfur dioxide in the flue gas is as follows:

[0061] When active calcium exists in the form of CaO, it reacts with sulfur dioxide and water to produce CaSO3 and hydrogen, but in actual reactions, hydrogen is usually ignored because its concentration in the reaction system is extremely low:

[0062] SO2+CaO→CaSO3 (in the presence of water vapor)

[0063] Calcium sulfate further reacts with oxygen to produce calcium sulfate:

[0064] 2CaSO3+O2→2CaSO4;

[0065] When active calcium exists in the form of calcium hydroxide, it reacts with sulfur dioxide and water to first generate calcium bisulfite and calcium hydroxide (but during the reaction, calcium hydroxide will be continuously consumed and regenerated, so its generation is usually not written separately). The reaction equation is as follows:

[0066] SO2+H2O+Ca(OH)2→Ca(HSO3)2;

[0067] The calcium bisulfite then reacts further with oxygen and calcium hydroxide to produce calcium sulfate and water:

[0068] 2Ca(HSO3)2+O2+2Ca(OH)2→4CaSO4+4H2O

[0069] Alternatively, if direct oxidation of sulfurous acid and formation of calcium sulfate is considered (without the intermediate step of calcium bisulfite), the reaction equation can be simplified to:

[0070] 2SO2+2Ca(OH)2+O2+2H2O→2CaSO4+4H2O;

[0071] S3, the flue gas after desulfurization is dedusted by the dust collector 71, so that impurities and desulfurization products in the flue gas can be removed from the flue gas;

[0072] S4. Under the pressure adsorption of the booster fan 8, the gas after dust removal enters the SCR reactor 3 for catalytic reduction and denitrification again. The denitrified gas is discharged through the chimney 4. The SCR denitrification technology refers to the use of reducing agents such as NH3, liquid ammonia, urea, etc. to selectively react with NOx in the flue gas under the action of a catalyst to generate non-toxic and non-polluting N2 and H2O. Its main reaction formula includes:

[0073] 4NO+4NH3+O2→4N2+6H2O

[0074] 2NO2+4NH3+O2→3N2+6H2O

[0075] 6NO2+8NH3→7N2+12H2O

[0076] After using the catalyst, the activation energy of the reaction is reduced, and the reaction can be carried out at a relatively low temperature of 300-400°C, which is equivalent to the flue gas temperature between the economizer and the air preheater. The SCR reactor 3 performs catalytic reduction and denitrification again, which is an efficient and environmentally friendly flue gas denitrification technology that can make the flue gas green.

[0077] S5. The dust after dust removal is uniformly processed through the dust storage bin 91, which is convenient for stable processing after dust removal;

[0078] The hybrid dry desulfurization and denitrification process adopts a hybrid dry desulfurization and denitrification device including: a boiler 1, a pretreatment unit 2, an SCR reactor 3, a chimney 4, an induced draft fan 5, a desulfurization unit 6, a dust removal unit 7 and a booster fan 8. The combustion material of the boiler 1 is particulate matter. The pretreatment unit 2 is installed on the boiler 1. The pretreatment unit 2 includes: a self-owned compressed air system 21, an ammonia water supply unit 22 and a reflux valve 23. The ammonia water supply unit 22 sprays ammonia water into the inner cavity of the boiler 1 through a spray gun. The self-owned compressed air system 21 is used for gas supply to the spray gun. The reflux valve 23 is installed in the reflux section of the flue gas, and the reflux valve 23 is in a normally closed state to avoid the phenomenon of flue gas reflux.

[0079] The ammonia water supply unit 22 includes: an ammonia water tank 2201 and an ammonia water pump 2202. The ammonia water pump 2202 is installed at the water outlet end of the ammonia water tank 2201. The ammonia water pump 2202 is used to supply water from the inner cavity of the ammonia water tank 2201 to the inner cavity of the spray gun. The ammonia water supply unit 22, the spray gun and the ammonia water pipeline constitute an ammonia water injection system. The ammonia water in the ammonia water tank 2201 is transported to the nozzle through the pipeline by the ammonia water pump 2202. The nozzle evenly sprays the ammonia water into the flue gas in the inner cavity of the boiler 1 for partial denitrification treatment.

[0080] Among them, the SCR reactor 3 is used for denitrification of flue gas. The SCR reactor 3 is installed near the chimney 4. The inner cavity of the SCR reactor 3 is loaded with a catalyst to facilitate catalytic reduction of the catalyst in the SCR reactor 3 and the flue gas for denitrification again. The chimney 4 is installed at the air outlet end of the SCR reactor 3. The induced draft fan 5 is used for negative pressure ventilation of the flue gas in the boiler 1 through the air duct. The air duct connection between the induced draft fan 5 and the boiler 1 is not shown in the attached figure. The flue gas in the boiler 1 can flow to the desulfurization unit 6 under the induced draft of the induced draft fan 5.

[0081] Specifically, the desulfurization unit 6 is installed at one end of the air outlet of the induced draft fan 5 through a pipeline. The desulfurization unit 6 includes: a desulfurization agent bin 61, a first bin top dust removal box 62, a first vibrating motor 63, a first star-shaped discharger 64, a metering conveyor 65, an electric heater 66, a first Roots blower 67, a second Roots blower 68 and a compressed air storage tank 69. The desulfurization agent bin 61 is used for desulfurization treatment of flue gas. The desulfurization agent in the desulfurization agent bin 61 is active calcium, and the active calcium is transported and supplied to the inner cavity of the desulfurization agent bin 61 by a conveyor vehicle. A humidifier is installed on the desulfurization agent bin 61 to facilitate the desulfurization treatment of flue gas. The first bin top dust removal box 62 is installed on the top of the desulfurization agent bin 61. The first bin top dust removal box 62 can perform dust reduction treatment on the inner cavity of the desulfurization agent bin 61. The first vibrating motor 63 is fixed to the desulfurization agent bin. The bottom of the desulfurizer bin 61 is provided with a first rapping motor 63, which can vibrate the bottom of the desulfurizer bin 61 to prevent the desulfurizer from blocking the discharge port, and ensure that the desulfurizer can flow out of the bin smoothly for use in subsequent production processes. The first star-shaped discharger 64 is installed at the bottom of the desulfurizer bin 61, so that the used desulfurizer can be discharged from the inner cavity of the desulfurizer bin 61. The metering conveyor 65 is installed at the discharge end of the first star-shaped discharger 64, so that the metering conveyor 65 can measure and convey the discharged desulfurizer. The electric heater 66 is arranged at the air inlet end of the metering conveyor 65, so that the electric heater 66 can create temperature conditions for the active calcium in the inner cavity of the desulfurizer bin 61 to contact with the flue gas, and the alkaline oxide on its surface will react with sulfur dioxide to generate calcium sulfate or other forms of sulfur compounds;

[0082] Among them, the first Roots blower 67 and the second Roots blower 68 are installed at one end of the electric heater 66 through a pipeline, so that the first Roots blower 67 and the second Roots blower 68 can blow the heated air into the inner cavity of the desulfurizer bin 61 through the pipeline, and the compressed air storage tank 69 is connected to the first bin top dust removal box 62 through the air supply pipeline, so that the compressed air storage tank 69 can supply air to the first bin top dust removal box 62, and the compressed air storage tank 69 is connected to the chimney 4 through a pipeline, and a waste heat recovery mechanism is installed at one end of the pipeline close to the chimney 4, which is convenient for the recovery and utilization of the flue gas heat in the chimney 4, and the setting of the compressed air storage tank 69 facilitates the acceleration of the gas circulation rate in the chimney 4.

[0083] More specifically, the first Roots blower 67 and the second Roots blower 68 are connected to the dust removal unit 7 through a pipeline, the compressed air storage tank 69 is connected to the dust removal unit 7 through an air supply pipeline, the dust removal unit 7 is installed between the desulfurization unit 6 and the booster fan 8, and the dust removal unit 7 includes: a dust collector 71, an ash hopper 72 and a second star-shaped discharger 73, one end of the dust collector 71 is connected to the air inlet end pipeline of the booster fan 8 through a non-metallic expansion joint, and the dust is separated from the gas by screening and dust removal of the dust collector 71, the ash hopper 72 is installed at the bottom of the dust collector 71, and the dust-removed particles can enter the inner cavity of the ash hopper 72, and the first The two-star discharger 73 is installed at the bottom of the ash hopper 72. The other end of the dust collector 71 is connected to the air outlet pipe of the induced draft fan 5 through a non-metallic expansion joint. The first Roots blower 67 and the second Roots blower 68 are connected to the pipe between the dust collector 71 and the induced draft fan 5 through a pipe, so that the first Roots blower 67 and the second Roots blower 68 can supply air to the dust collector 71 and blow the desulfurized flue gas into the inner cavity of the dust collector 71. The air outlet end of the booster fan 8 is connected to the chimney 4 through the SCR reactor 3, so that the flue gas dedusted by the dust collector 71 can enter the inner cavity of the SCR reactor 3 through the booster fan 8.

[0084] In particular, the second star-shaped discharger 73 is provided with an ash storage unit 9 via a discharge pipe, and the ash storage unit 9 comprises: an ash storage bin 91, a second bin top dust removal box 92, a second vibrating motor 93, a discharge hopper 94 and a Roots vacuum pump 95, the ash storage bin 91 is connected to the second star-shaped discharger 73 via a discharge pipe, the second bin top dust removal box 92 is installed at the top of the ash storage bin 91, the second vibrating motor 93 is installed at the bottom of the ash storage bin 91, and the discharge hopper 94 is installed at the bottom of the ash storage bin 91. The discharge hopper 94 is used to discharge the ash in the ash storage bin 91. Through the setting of the second vibrating motor 93, the dust in the inner cavity of the ash storage bin 91 can be stably discharged from the discharge hopper 94. The Roots vacuum pump 95 is connected to the top of the second bin top dust removal box 92 through a vacuum pipe. The second bin top dust removal box 92 is connected to the outlet pipe of the compressed air storage tank 69 through a pipe, so that the second bin top dust removal box 92 can stably remove dust from the inner cavity of the ash storage bin 91 and reduce the influence of dust on the flue gas.

[0085] In summary, this process has great advantages in terms of stable, reliable, efficient operation, and extremely low operation and maintenance costs. It is installed behind the high-temperature fan and will not affect the heating of the boiler 1. The operation cost is low. Compared with the high-temperature and high-dust method, the dry desulfurization process is simple, without sewage, low energy consumption, and the temperature of the flue gas after desulfurization is high, which is conducive to the exhaust diffusion of the chimney 4 and will not produce white smoke. The purified flue gas does not require secondary heating and has low corrosiveness.

[0086] Working principle of the present invention:

[0087] When in use, ammonia water is sprayed into the inner cavity of boiler 1 through a spray gun, and the SNCR non-catalytic reduction denitrification process is used to remove part of the NO in the flue gas in the inner cavity of boiler 1. X The partially denitrified flue gas enters the desulfurizer bin 61 for desulfurization treatment under the suction of the induced draft fan 5. The desulfurized flue gas passes through the dust collector 71 for dust removal. Under the pressure adsorption of the booster fan 8, the denitrified gas enters the SCR reactor 3 for catalytic reduction and denitrification again. The denitrified gas is discharged through the chimney 4, and the dust after dust removal passes through the ash storage bin 91 for unified dust treatment.

[0088] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A hybrid dry desulfurization and denitrification process, characterized in that: The invention comprises a mixed dry desulfurization and denitrification device, and further comprises the following steps: S1. Spray ammonia water into the boiler cavity through a spray gun, and use SNCR non-catalytic reduction denitrification process to remove part of NO in the flue gas. X ; S2. The partially denitrated flue gas enters the desulfurizer bin for desulfurization treatment under the suction of the induced draft fan; S3, the flue gas after desulfurization is dedusted by a dust collector; S4. Under the pressure adsorption of the booster fan, the gas after dust removal enters the SCR reactor for catalytic reduction and denitrification again, and the denitrified gas is discharged through the chimney; S5. The dust after dust removal is uniformly processed through the dust storage bin; The hybrid dry desulfurization and denitrification process adopts a hybrid dry desulfurization and denitrification device comprising: A boiler (1), wherein the combustion material of the boiler (1) is particulate matter; A pretreatment unit (2), wherein the pretreatment unit (2) is installed on the boiler (1); An SCR reactor (3), wherein the SCR reactor (3) is used for denitrification of flue gas; A chimney (4), wherein the chimney (4) is installed at the gas outlet end of the SCR reactor (3); An induced draft fan (5), the induced draft fan (5) is used for negative pressure draft of the flue gas in the boiler (1) through an air duct; A desulfurization unit (6), wherein the desulfurization unit (6) is installed at one end of the air outlet of the induced draft fan (5) through a pipeline; A dust removal unit (7) and a booster fan (8), wherein the dust removal unit (7) is installed between the desulfurization unit (6) and the booster fan (8).

2. A hybrid dry desulfurization and denitrification process according to claim 1, characterized in that: The pretreatment unit (2) comprises: an autonomous compressed air system (21), an ammonia water supply unit (22) and a reflux valve (23); the ammonia water supply unit (22) sprays ammonia water into the inner cavity of the boiler (1) through a spray gun; the autonomous compressed air system (21) is used for gas supply to the spray gun; the reflux valve (23) is installed in the reflux section of the flue gas, and the reflux valve (23) is in a normally closed state.

3. A hybrid dry desulfurization and denitrification process according to claim 2, characterized in that: The ammonia water supply unit (22) comprises: an ammonia water tank (2201) and an ammonia water pump (2202), wherein the ammonia water pump (2202) is installed at the water outlet end of the ammonia water tank (2201), and the ammonia water pump (2202) is used to supply water in the inner cavity of the ammonia water tank (2201) to the inner cavity of the spray gun.

4. A hybrid dry desulfurization and denitrification process according to claim 1, characterized in that: The desulfurization unit (6) comprises: A desulfurizing agent bin (61), wherein the desulfurizing agent bin (61) is used for desulfurization of flue gas; A first silo top dust removal box (62), wherein the first silo top dust removal box (62) is installed on the top of the desulfurizing agent silo (61); A first rapping motor (63), wherein the first rapping motor (63) is fixed to the bottom of the desulfurizing agent bin (61); A first star-shaped discharger (64), the first star-shaped discharger (64) being installed at the bottom of the desulfurizing agent bin (61); A metering conveyor (65), wherein the metering conveyor (65) is installed at the discharge end of the first star-shaped discharger (64); An electric heater (66), wherein the electric heater (66) is arranged at the air inlet end of the metering conveyor (65); A first Roots blower (67) and a second Roots blower (68), wherein the first Roots blower (67) and the second Roots blower (68) are installed at one end of the electric heater (66) through a pipeline; A compressed air storage tank (69) is connected to the first silo top dust removal box (62) via an air supply duct.

5. A hybrid dry desulfurization and denitrification process according to claim 4, characterized in that: The first Roots blower (67) and the second Roots blower (68) are connected to the dust removal unit (7) via a pipeline, and the compressed air storage tank (69) is connected to the dust removal unit (7) via an air supply pipeline.

6. A hybrid dry desulfurization and denitrification process according to claim 1, characterized in that: The dust removal unit (7) comprises: A dust collector (71), one end of which is connected to the air inlet end duct of the booster fan (8) via a non-metallic expansion joint; An ash hopper (72), wherein the ash hopper (72) is installed at the bottom of the dust collector (71); A second star-shaped discharger (73), wherein the second star-shaped discharger (73) is installed at the bottom of the ash hopper (72).

7. A hybrid dry desulfurization and denitrification process according to claim 6, characterized in that: The other end of the dust collector (71) is connected to the air outlet pipe of the induced draft fan (5) via a non-metallic expansion joint.

8. A hybrid dry desulfurization and denitrification process according to claim 6, characterized in that: The second star-shaped discharger (73) is provided with an ash storage unit (9) via a discharge pipe, and the gas outlet end of the booster fan (8) is connected to the chimney (4) via an SCR reactor (3).

9. A hybrid dry desulfurization and denitrification process according to claim 8, characterized in that: The ash storage unit (9) comprises: An ash storage bin (91), wherein the ash storage bin (91) is connected to the second star-shaped discharger (73) via a discharge pipe; A second silo top dust removal box (92), the second silo top dust removal box (92) is installed on the top of the ash storage silo (91); A second rapping motor (93), wherein the second rapping motor (93) is installed at the bottom of the ash storage bin (91); A discharge hopper (94), the discharge hopper (94) being installed at the bottom of the ash storage bin (91), the discharge hopper (94) being used to discharge ash in the ash storage bin (91); A Roots vacuum pump (95) is connected to the top of the second silo top dust removal box (92) through a vacuum pipeline.

10. A hybrid dry desulfurization and denitrification process according to claim 9, characterized in that: The second silo top dust removal box (92) is connected to the air outlet pipe of the compressed air storage tank (69) via a pipeline.

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