A high-sulfur yellow phosphorus tail gas boiler flue gas purification treatment system and method

Abstract

The application discloses a high-sulfur yellow phosphorus tail gas boiler flue gas purification treatment system and method, relates to the technical field of yellow phosphorus tail gas boiler flue gas treatment, and solves the problem of low removal efficiency of unit slaked lime on sulfur-containing impurities in the removal process of sulfur-containing impurities in the boiler flue gas after yellow phosphorus tail gas combustion. The application comprises the following steps: step 1, yellow phosphorus tail gas is graded combustion, preliminary desulfurization, denitrification and dephosphorization are carried out at the same time of combustion, and high-temperature flue gas is obtained; step 2, the high-temperature flue gas is cooled to 230-280 DEG C; step 3, the flue gas in step 2 is subjected to first dust removal; step 4, the flue gas after the first dust removal in step 3 is mixed with sprayed slaked lime powder to be thoroughly desulfurized, and cooling water is sprayed to be cooled in the desulfurization process; step 5, the flue gas after the thorough desulfurization obtained in step 4 is subjected to second dust removal; and step 6, the flue gas after the second dust removal in step 5 is exhausted. The application aims to create suitable temperature for continuous desulfurization through accurate control of flue gas temperature.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of yellow phosphorus tail gas boiler flue gas treatment, and particularly relates to a high-sulfur yellow phosphorus tail gas boiler flue gas purification treatment system and method. BACKGROUND

[0002] Yellow phosphorus tail gas is a byproduct generated by an electric furnace in a yellow phosphorus production process, and mainly includes phosphine (PH3), hydrogen sulfide (H2S), sulfur dioxide (SO2), elemental phosphorus (P) and carbon monoxide (CO) and the like; in view of the high heat value, a production unit often recovers it to be used as boiler fuel gas, so as to realize the recycling of energy; the sulfur, nitrogen, phosphorus and other impurities in the yellow phosphorus tail gas are converted into harmful pollutants such as sulfates, nitrogen oxides and phosphates in the combustion process, which have potential harm to the environment and human health, therefore, strict requirements are put forward for the emission standards of boiler flue gas by countries, and the yellow phosphorus tail gas needs to be deeply purified; traditional desulfurization technologies mainly include wet desulfurization, dry desulfurization and semi-dry desulfurization, the wet desulfurization usually uses limestone or slaked lime as an absorbent to remove SO2 through a wet scrubber; the denitration technology is mainly divided into selective catalytic reduction (SCR), selective non-catalytic reduction (SNCR) and adsorption method and the like; the dephosphorization technology usually involves a chemical precipitation method, and uses certain chemicals to react with phosphorus to generate insoluble precipitates, so as to realize the removal of phosphorus.

[0003] However, in the existing removal process of sulfur impurities in the yellow phosphorus tail gas, the removal efficiency of unit slaked lime on the sulfur impurities is low, and cannot be adaptively adjusted according to the flow of the yellow phosphorus tail gas; and the solid particles generated in the desulfurization process can cause fouling or blockage in the equipment, affecting the normal operation of the system; due to different phosphorus ore producing areas and harmful element contents, the sulfur content in the yellow phosphorus tail gas is wide and fluctuates greatly, and the operation time of the yellow phosphorus electric furnace is affected by the electricity price in different provinces in China to different degrees, which indicates that the utilization of the yellow phosphorus tail gas cannot achieve the goal of stable operation like traditional gas power plants or chemical plants with stable raw material sources, and the desulfurization device is difficult to realize stable and effective operation. SUMMARY

[0004] To solve the above technical problems, the application provides a high-sulfur yellow phosphorus tail gas boiler flue gas purification treatment system and method, and accurate control of the temperature of flue gas cooling is crucial to the desulfurization process, and too high or too low temperature can affect the rate and efficiency of the desulfurization reaction; the application can effectively reduce the temperature of the yellow phosphorus tail gas boiler flue gas by spraying cooling water, and the accurate control of the flue gas temperature can be realized by adjusting the spraying amount and temperature of the cooling water, so as to create suitable temperature conditions for continuous desulfurization reaction.

[0005] The technical scheme adopted by the application is as follows:

[0006] A high-sulfur yellow phosphorus tail gas boiler flue gas purification treatment system, comprising a desulfurization tower, a first gas inlet is arranged on the desulfurization tower, a plurality of first nozzles are arranged in the desulfurization tower, and two of the first nozzles are arranged on the upper and lower sides of the first gas inlet; the device further comprises a power generation boiler, a buffer assembly and a first dust removal assembly connected in sequence, and the air outlet of the first dust removal assembly is communicated with the first gas inlet of the desulfurization tower through a pipeline.

[0007] A high-sulfur yellow phosphorus tail gas boiler flue gas purification treatment method, comprising the following steps:

[0008] Step 1: The yellow phosphorus tail gas is staged combustion, and preliminary desulfurization, denitrification and dephosphorization are carried out at the same time, so as to obtain high-temperature flue gas;

[0009] Step 2: The high-temperature flue gas is cooled to t1, and t1 ranges from 140 to 200℃;

[0010] Step 3: The flue gas in step 2 is subjected to first dust removal;

[0011] Step 4: The flue gas after first dust removal in step 3 is mixed with sprayed lime powder for complete desulfurization, and cooling water is sprayed for cooling during the desulfurization process;

[0012] Step 5: The flue gas after complete desulfurization obtained in step 4 is subjected to second dust removal;

[0013] Step 6: The flue gas after second dust removal obtained in step 5 is exhausted.

[0014] Preferably, in step 1, limestone is sprayed for preliminary desulfurization, urea is sprayed for denitrification, and coal gangue powder is sprayed for dephosphorization.

[0015] Preferably, in step 1, the large particle size coal gangue after dephosphorization is returned to the dephosphorization step in step 1 for continuous dephosphorization.

[0016] Preferably, in step 3, the first dust removal is carried out by an electrostatic precipitator, and in step 5, the second dust removal is carried out by a bag-type dust collector.

[0017] Preferably, in step 4, the complete desulfurization comprises the following steps:

[0018] Step 401: Step 4 is carried out in a desulfurization tower, the flue gas is introduced into the desulfurization tower, and a thermometer monitors the temperature of the flue gas introduced into the desulfurization tower in real time;

[0019] Step 402: The control system receives the feedback of the flue gas temperature in real time, and sends a signal to the spray head of the sprayed cooling water mist, so that the cooling water mist is sprayed to cool the flue gas to a temperature t2;

[0020] Step 403: When the temperature drops to t2, the slaked lime powder is sprayed, and at this time, the spray head maintains the spraying of the cooling water mist to maintain the real-time temperature of the flue gas at t2, and at the same time, the airflow is introduced to make the slaked lime powder suspended in the flue gas and the cooling water mist;

[0021] Step 404: The slaked lime powder spraying is maintained for T time, and the reacted slaked lime powder is discharged, so that new slaked lime powder is sprayed.

[0022] Preferably, in step 402, the production state of the power boiler is different in different time periods, the tail gas supply amount, i.e., the load of the boiler, is different, and therefore, according to the tail gas supply amount of the power boiler, the initial temperature introduced into the desulfurization tower changes, and the size of the cooling water mist is adjusted according to the initial temperature, and when the real-time temperature is maintained at t2, the cooling water mist is maintained at the size.

[0023] Preferably, in step 404, T is 40-60 min.

[0024] Preferably, in step 402, t2 is 100-130℃.

[0025] Preferably, in step 402, the temperature of the sprayed cooling water mist is normal temperature, the flow rate is 0-7.5 t / h, and the spraying area of the water mist covers the cross section of the desulfurization tower.

[0026] As described above, due to the adoption of the above technical solutions, the present application has the following beneficial effects:

[0027] 1. Precise control of the temperature of the flue gas is crucial for the desulfurization process, and too high or too low temperature can affect the rate and efficiency of the desulfurization reaction. The present application can effectively reduce the temperature of the yellow phosphorus tail gas boiler flue gas by spraying cooling water, and by adjusting the spraying amount and temperature of the cooling water, the temperature of the flue gas can be precisely controlled to create suitable temperature conditions for continuous desulfurization reaction;

[0028] 2. The spraying of the cooling water not only reduces the temperature of the flue gas, but also causes a hydration reaction with the unreacted quicklime (CaO) in the slaked lime to generate more calcium hydroxide (Ca(OH)2), which helps to improve the activity and reactivity of the slaked lime, optimize the desulfurization reaction conditions, improve the SO2 removal rate, improve the utilization efficiency and desulfurization efficiency of the slaked lime, reduce the amount of desulfurization agent used, reduce the operating cost, improve the economy of the system, reduce the emission of pollutants, and consume the unreacted quicklime in the slaked lime, reduce its accumulation in the desulfurization system, and avoid blockage or wear of the equipment and pipelines;

[0029] 3. Due to the improvement of the desulfurization efficiency, the secondary pollutants that may be generated in the desulfurization process, such as the emission of sulfates or sulfites, can be reduced;

[0030] 4. By precisely controlling the flue gas temperature and optimizing the use of desulfurizer, the reliability and stability of the entire desulfurization system can be improved, and the downtime caused by equipment failure or operation error can be reduced.

[0031] 5. By monitoring the flue gas temperature entering the desulfurization tower in real time, the actual production of yellow phosphorus tail gas can be adjusted, and stable operation of the desulfurization device can be realized, so that the yellow phosphorus tail gas is realized. Resource utilization, and the generated waste gas also obtains a more stable and effective treatment method. BRIEF DESCRIPTION OF DRAWINGS

[0032] The present application will be described by way of example and with reference to the accompanying drawings, in which:

[0033] Figure 1 is a structural schematic diagram of the in-furnace desulfurization, denitrification and dephosphorization device for high-sulfur yellow phosphorus tail gas boiler flue gas in the present application;

[0034] Figure 2 is a structural schematic diagram of the desulfurization tower in the present application;

[0035] Figure 3 is an enlarged structural schematic diagram of the A part in the present application. Figure 2

[0036] REFERENCE NUMERALS

[0037] 1-desulfurization tower, 2-first gas inlet, 3-gas outlet, 4-first nozzle, 5-first channel, 6-sprayer, 7-fixed plate, 8-second nozzle, 9-rotating shaft, 10-anti-sticking layer, 11-power generation boiler, 12-third nozzle, 13-fourth nozzle, 14-separator, 15-second channel, 16-second gas inlet, 17-buffering assembly, 18-slag outlet, 19-first dust removal assembly, 20-second dust removal assembly, 21-emptying tower. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0039] The present application will be described in detail below. Figures 1 to 3

[0040] Embodiment 1

[0041] A high-sulfur yellow phosphorus tail gas boiler flue gas purification treatment system, referring to the accompanying drawings Figure 1 ​​, including desulfurization tower 1, the first gas inlet 2 is arranged on the desulfurization tower 1, the inside of the desulfurization tower 1 is provided with a plurality of first nozzles 4, and two of the first nozzles 4 are arranged on the upper and lower sides of the first gas inlet 2;By arranging the first nozzles 4 on the upper and lower sides of the first gas inlet 2 of the desulfurization tower 1, the first nozzles 4 spray water mist, thereby rapidly reducing the temperature of the sulfur-containing flue gas sprayed at the first nozzles 4, and the mist sprayed at the first nozzles 4 can cause the quicklime in the slaked lime to react completely, thereby improving the utilization efficiency of the slaked lime;The water mist sprayed by the first nozzles 4 can wash the slaked lime attached to the inside of the desulfurization tower 1.

[0042] Wherein, the first gas inlet 2 is used for entering the sulfur-containing flue gas.

[0043] Wherein, the first nozzle 4 is connected with the water source through a pipeline, and a water pump is also installed on the pipeline.

[0044] In the embodiment, the desulfurization tower 1 is connected with a first channel 5 for inputting slaked lime, and the tail end of the first channel 5 is communicated with the inside of the desulfurization tower 1 through a spray head 6;The first channel 5 is used for inputting slaked lime, and the spray head 6 can spray the slaked lime.

[0045] Wherein, the first channel 5 is connected with a slaked lime powder supply end at the head end, and a booster pump is also connected with the spray head 6.

[0046] In the embodiment, the inside of the desulfurization tower 1 is also provided with a fixed plate 7, and a plurality of second nozzles 8 are arranged on the fixed plate 7;By arranging the second nozzles 8 on the fixed plate 7, the second nozzles 8 are used for spraying gas flow, so that the slaked lime powder is fully blown away and mixed with the sulfur-containing flue gas for sufficient reaction.

[0047] Wherein, the plurality of second nozzles 8 are connected with a gas pump through a pipeline and a universal joint.

[0048] In the embodiment, referring to the accompanying drawings Figure 2 The fixed plate 7 is provided with two, and the two fixed plates 7 are respectively hinged with the inner wall of the desulfurization tower 1 through a rotating shaft 9;After the slaked lime and the sulfur-containing flue gas are fully reacted, the waste slaked lime needs to be discharged, at this time, the fixed plate 7 is opened by rotating the rotating shaft 9, and the slaked lime is discharged through the bottom discharge port of the desulfurization tower 1.

[0049] In the embodiment, the inner wall of the desulfurization tower 1 is provided with an anti-sticking layer 10;The anti-sticking layer 10 further avoids the problem that the solid particles generated in the desulfurization process cause fouling or blockage in the equipment.

[0050] In the embodiment, referring to the accompanying drawings Figure 3The device further comprises a power generation boiler 11, a buffer assembly 17 and a first dust removal assembly 19 connected in sequence through pipelines, and an air outlet of the first dust removal assembly 19 is communicated with the first air inlet 2 of the desulfurization tower 1 through a pipeline; the power generation boiler 11 discharges sulfur-containing flue gas after power generation, the buffer assembly 17 adjusts the temperature of the sulfur-containing flue gas to avoid overheating of the sulfur-containing flue gas, and the first dust removal assembly 19 removes dust in the sulfur-containing flue gas, and the sulfur-containing flue gas after preliminary dust removal is introduced into the desulfurization tower 1.

[0051] The buffer assembly 17 comprises a containing tower, and the containing tower comprises, from top to bottom, a high-temperature superheater, a low-temperature superheater and a plurality of air preheaters.

[0052] The first dust removal assembly 19 comprises an electrostatic precipitator.

[0053] The upper portion of the power generation boiler 11 is further communicated with a feeding port for introducing coal gangue.

[0054] In the embodiment, the gas outlet 3 of the desulfurization tower 1 is communicated with a second dust removal assembly 20 and an emptying tower 21 in sequence through pipelines; the second dust removal assembly 20 is used for thoroughly removing dust from the flue gas discharged from the desulfurization tower 1, and finally the flue gas is introduced into the emptying tower 21 for emptying.

[0055] The second dust removal assembly 20 comprises a bag-type dust collector.

[0056] In the embodiment, the lower portion of the buffer assembly 17 is provided with a slag outlet 18; the slag outlet 18 is used for discharging ash and slag falling from the buffer assembly 17.

[0057] In the embodiment, the sidewall of the power generation boiler 11 is respectively provided with a third nozzle 12 and a fourth nozzle 13; the sidewall of the bottom of the power generation boiler 11 is further provided with a second air inlet 16; the third nozzle 12 and the fourth nozzle 13 respectively spray in limestone powder and urea for dephosphorization and desulfurization.

[0058] The third nozzle 12 is connected with the limestone powder through a pipeline, and a high-pressure pump is installed on the pipeline.

[0059] The fourth nozzle 13 is connected with the urea supply end through a pipeline, and a high-pressure pump is installed on the pipeline.

[0060] In the embodiment, a separator 14 is connected between the power generation boiler 11 and the buffer assembly 17 through a pipeline, the bottom of the separator 14 is connected with the sidewall of the power generation boiler 11 through a second channel 15; the separator 14 is used for separating coal gangue introduced into the power generation boiler 11, the coal gangue passes through the separator 14, the particles with large particle size continue to enter the power generation boiler 11 for dephosphorization, and the particles with small particle size, i.e., fine particles, enter the rear-end flue gas treatment system after being pretreated by a dust collector, i.e., in the desulfurization tower 1 for second-stage desulfurization.

[0061] The separator 14 is a cyclone separator 14.

[0062] Examples 2-8 and Comparative Examples 1-3

[0063] The flue gas is purified according to the method for purifying flue gas of high-sulfur yellow phosphorus tail gas boiler, and the device described in Example 1 is used, which includes the following steps:

[0064] Step 1: The yellow phosphorus tail gas is burned in the power boiler 11, and preliminary desulfurization (by spraying limestone powder through the third nozzle 12), denitrification (by spraying urea through the fourth nozzle 13), and dephosphorization (by introducing coal gangue into the boiler) are carried out at the same time, obtaining high-temperature flue gas with a temperature of 360-390°C.

[0065] Step 2: The high-temperature flue gas is cooled to t1 through the air preheater and the coal economizer, and t1 ranges from 140 to 200°C. The upper and lower limits of the range of t1 are set to ensure the best heat exchange effect of the high-temperature flue gas while saving energy as much as possible. Moreover, reducing the temperature of the high-temperature flue gas to a suitable temperature helps to reduce the temperature of the subsequent flue gas in the desulfurization tower, thereby balancing the subsequent water spraying amount and making the water content in the flue gas reach a most reasonable value, which better controls the acid dew point and reduces the corrosion of the equipment.

[0066] Step 3: The flue gas in step 2 is subjected to first dust removal, which is carried out in the first dust removal assembly 19.

[0067] Step 4: The flue gas after the first dust removal in step 3 is mixed with sprayed lime powder for thorough desulfurization, and cooling water is sprayed for cooling during the desulfurization process.

[0068] Step 5: The flue gas after thorough desulfurization obtained in step 4 is subjected to second dust removal, which is carried out in the second dust removal assembly 20.

[0069] Step 6: The flue gas after the second dust removal in step 5 is exhausted through the exhaust tower 21.

[0070] In this example, limestone is sprayed in step 1 for preliminary desulfurization, urea is sprayed for denitrification, and coal gangue powder is sprayed for dephosphorization.

[0071] In this example, the large-particle-size coal gangue after dephosphorization in step 1 is returned to the dephosphorization step in step 1 for continued dephosphorization.

[0072] In this example, electrostatic precipitators are used for first dust removal in step 3, and bag-type dust collectors are used for second dust removal in step 5.

[0073] In this embodiment, the complete desulfurization in step 4 includes the following steps:

[0074] Step 401: Step 4 is carried out in the desulfurization tower 1, and the flue gas is introduced into the desulfurization tower 1, and the thermometer monitors the temperature of the flue gas introduced into the desulfurization tower 1 in real time;

[0075] Step 402: The control system receives the feedback of the flue gas temperature in real time, and sends a signal to the spray head 6 for spraying cooling water mist, so that the cooling water mist is sprayed to cool the flue gas to a temperature t2;

[0076] Step 403: When the thermometer detects that the temperature drops to t2, the spray of quicklime powder is started, and at this time the spray head 6 maintains the spraying of cooling water mist to maintain the real-time temperature of the flue gas at t2, and at the same time the airflow is introduced to make the quicklime powder suspended in the flue gas and the cooling water mist;

[0077] Step 404: The quicklime powder is continuously sprayed, and the reaction T time is completed, the quicklime powder contacts the boiler flue gas, is carried along with the flue gas to the bag filter, and reacts with the sulfur dioxide in the flue gas at all times during the period, until it is discharged from the hopper below the bag filter, thereby renewing the quicklime powder, which can keep the quicklime powder in the absorption tower always active.

[0078] In this embodiment, in step 402, the production state of the power generation boiler 11 is different at different time periods, the tail gas supply amount, i.e. the load of the boiler, is different, so according to the tail gas supply amount of the power generation boiler 11, the initial temperature introduced into the desulfurization tower 1 will change, and the size of the cooling water mist is adjusted according to the initial temperature, and when the real-time temperature is maintained at t2, the cooling water mist is maintained at this size.

[0079] In this embodiment, in step 404, T is 50 min.

[0080] In this embodiment, in step 402, t2 is 100-130°C.

[0081] In this embodiment, in step 402, the temperature of the sprayed cooling water mist is normal temperature, the flow rate is 0-7.5 t / h, and the area covered by the sprayed water mist covers the cross section of the desulfurization tower 1.

[0082] Table 1: t1, t2, the amount of quicklime required for removing sulfur impurities in flue gas, and the time table of consumed sulfur impurities in examples 2-8 and comparative examples 1-3.

[0083] The absorption section length of the desulfurization tower 1 is about 32 m, and in the actual operation, when the boiler load reaches 60 t / h or more, the flue gas flow rate is about 3-5 m 3 / s, and the reaction time is about 6.5-10 s; when the boiler load is 35-60 t / h, the flue gas flow rate is 1.5-3 m 3 / s, reaction time is about 10-21s, and the flue gas entraining the lime enters the bag filter. The main reaction is carried out in the desulfurization tower 1.

[0084]

[0085]

[0086] In the examples 1-3, t1 and t2 are selected at a temperature lower than the range disclosed in the present application, and in the examples 4-6, t1 and t2 are selected at a temperature higher than the range disclosed in the present application. In the low temperature state, the desulfurization and denitrification will be affected. In the case of super high temperature, although the removal of nitrogen oxides will not be affected, the removal of sulfur dioxide will be affected. Therefore, only when t1 and t2 are in the most suitable temperature range, the desulfurization and denitrification effects can be optimal.

[0087] In the above table 1, the ratio of the removal of unit concentration of sulfur dioxide to the consumption of lime is [the set concentration of sulfur dioxide before removal (monitoring value) - the concentration after removal (monitoring value)] / the actual consumption of lime.

[0088] From the data in the above table 1, it can be seen that when the temperature t1 is controlled at 140-200℃ and the temperature t2 is controlled at 100-130℃, the removal efficiency of sulfur dioxide is the highest, and the actual consumption of lime is the least.

[0089] It should be noted that:

[0090] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for purifying and treating flue gas from a high-sulfur, yellow phosphorus tail gas boiler, characterized in that, The device includes a desulfurization tower (1), on which a first air inlet (2) is provided, and inside the desulfurization tower (1) are several first nozzles (4), wherein two of the first nozzles (4) are located on the upper and lower sides of the first air inlet (2); the device also includes a power generation boiler (11), a buffer assembly (17), and a first dust removal assembly (19) connected in sequence, and the air outlet of the first dust removal assembly (19) is connected to the first air inlet (2) of the desulfurization tower (1) through a pipe; The first air inlet (2) is used to introduce sulfur-containing flue gas; The first nozzle (4) is connected to the water source through a pipe, and a water pump is also installed on the pipe; The desulfurization tower (1) is connected to a first channel (5) for inputting quicklime. The end of the first channel (5) is connected to the interior of the desulfurization tower (1) through a nozzle (6). The first channel (5) is used to input quicklime, and the nozzle (6) can spray the quicklime out. The first end of the first channel (5) is connected to the quicklime powder supply end, and a booster pump is also connected to the nozzle (6); The desulfurization tower (1) is also equipped with a fixed plate (7), and several second nozzles (8) are provided on the fixed plate (7); by providing the second nozzles (8) on the fixed plate (7), the second nozzles (8) are used to spray out gas flow, thereby fully dispersing the quicklime powder and mixing it with the sulfur-containing flue gas for full reaction; Several second nozzles (8) are connected to the air pump via pipes and universal joints; Use the following steps: Step 1: The yellow phosphorus tail gas is staged for combustion, and preliminary desulfurization, denitrification and dephosphorization are carried out during combustion to obtain high-temperature flue gas; Step 2: Cool the high-temperature flue gas to t1, where t1 ranges from 180 to 190°C; Step 3: Perform the first dust removal on the flue gas from Step 2; Step 4: Mix the flue gas after the first dust removal in Step 3 with the sprayed quicklime powder for thorough desulfurization. During the desulfurization process, spray cooling water to cool down the flue gas. Step 4, complete desulfurization, includes the following steps: Step 401: Step 4 is carried out in the desulfurization tower (1). Flue gas is introduced into the desulfurization tower (1), and the temperature of the flue gas introduced into the desulfurization tower (1) is monitored in real time by a thermometer. Step 402: The control system receives feedback on the flue gas temperature in real time and sends a signal to the nozzle (6) that sprays cooling water mist, thereby spraying cooling water mist to cool the flue gas to temperature t2. In step 402, the production status of the power generation boiler (11) is different at different times, and the tail gas supply, i.e. the boiler load, is different. Therefore, the tail gas supply of the power generation boiler (11) changes, and the initial temperature in the desulfurization tower (1) will change. The size of the cooling water mist is adjusted according to the initial temperature. When the real-time temperature is maintained at t2, the cooling water mist is maintained at that size. In step 402, t2 is 115~120℃; The temperature of the cooling water mist sprayed in step 402 is normal, the flow rate is 0~7.5t / h, and the area of ​​the sprayed water mist covers the cross section of the desulfurization tower (1); Step 403: When the thermometer detects that the temperature has dropped to t2, quicklime powder is sprayed into the flue gas. At this time, the nozzle (6) maintains the spraying of cooling water mist to keep the real-time temperature of the flue gas at t2. At the same time, the airflow is introduced to suspend the quicklime powder in the flue gas and cooling water mist. Step 404: Spray quicklime powder and maintain for time T. The reacted quicklime powder is discharged, and then fresh quicklime powder is sprayed to replace it. In step 404, T is 50 min; Step 5: Perform a second dust removal process on the completely desulfurized flue gas obtained in Step 4; Step 6: Discharge the flue gas obtained after the second dust removal in Step 5.

2. The method for purifying and treating high-sulfur, yellow phosphorus tail gas boiler flue gas according to claim 1, characterized in that, In step 1, limestone is sprayed for preliminary desulfurization, urea is sprayed for denitrification, and coal gangue powder is sprayed for dephosphorization.

3. The method for purifying and treating high-sulfur, yellow phosphorus tail gas boiler flue gas according to claim 2, characterized in that, Large-particle coal gangue from step 1, after dephosphorization, is returned to the dephosphorization step in step 1 for further dephosphorization.

4. The method for purifying and treating high-sulfur, yellow phosphorus tail gas boiler flue gas according to claim 1, characterized in that, In step 3, the first dust removal is carried out using an electrostatic precipitator, and in step 5, the second dust removal is carried out using a bag filter.

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