A sulfur recovery tail gas dedusting, desulfurization and denitration integrated system and method

Abstract

The application provides a sulfur recovery tail gas dry dedusting desulfurization and denitrification integrated system, which comprises a pretreatment device, a fixed bed dry desulfurization device, an SCR denitrification reactor and an induced draft fan; the first gas outlet of the pretreatment device is connected with the second gas inlet of the fixed bed dry desulfurization device, the second gas outlet of the fixed bed dry desulfurization device is connected with the third gas inlet of the SCR denitrification reactor; the gas inlet of the induced draft fan is connected with the third gas outlet of the SCR denitrification reactor; the pretreatment device is used for tail gas dedusting, the fixed bed dry desulfurization device is used for tail gas desulfurization, and the SCR denitrification reactor is used for tail gas denitrification. The application also provides a dedusting, desulfurization and denitrification integrated method. The sulfur recovery tail gas dry dedusting desulfurization and denitrification integrated system of the application realizes integrated dedusting, desulfurization and denitrification synergistic treatment of the sulfur recovery tail gas, the dedusting, desulfurization and denitrification integrated method of the application does not consume water in the treatment process and the by-products are easy to clean, and the treatment effect of the sulfur recovery tail gas is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coal chemical industry incinerator flue gas desulfurization and denitrification and dust removal, and particularly relates to a sulfur recovery tail gas dust removal, desulfurization and denitrification integrated system and method. BACKGROUND

[0002] Most of the sulfur recovery devices in the coal chemical industry use the AGCU patented process or a similar process for production, which integrates the Claus process and the tail gas absorption process. The tail gas of the sulfur recovery device is burned in the incinerator, and residual hydrogen sulfide, carbonyl sulfide, carbon disulfide and liquid sulfur are burned into sulfur dioxide, and other combustibles such as hydrocarbons, hydrogen and carbon monoxide are also burned, and are discharged through a chimney. The hot tail gas from the sulfur recovery device leaves the incinerator and exchanges heat with the incinerator waste heat boiler, and recovers heat by generating saturated low-pressure steam, which is then supplied to the steam users in the device.

[0003] For sulfur recovery tail gas desulfurization, the commonly used desulfurization process is limestone-gypsum wet desulfurization or ammonia desulfurization process, but due to the complex composition of the sulfur recovery tail gas, these two common processes have defects in operation. The limestone-gypsum wet desulfurization process consumes a large amount of water, and because the byproduct gypsum has low quality, it has a greater impact on the system during the maintenance of the sulfur recovery device; the ammonia desulfurization process has wide adaptability to the sulfur content in coal, but because the composition of the sulfur recovery tail gas is complex, the quality of the byproduct ammonium sulfate is poor, it is difficult to handle in the later stage, and a large amount of water is consumed in the process.

[0004] For the denitrification of sulfur recovery tail gas, the appropriate flue gas temperature range meets the SCR selective catalytic reduction process, but in the low-concentration flue gas nitrogen oxide treatment of sulfur recovery tail gas, the existing SCR system has a lag in the matching of ammonia injection amount and flue gas parameters, which can easily lead to excessive ammonia in the flue gas. For the dust removal of sulfur recovery tail gas, the existing technology usually removes particulate matter in wet desulfurization, which has a certain advancement in process, but also reduces the quality of the desulfurization byproduct and increases the difficulty of its recycling. SUMMARY

[0005] In view of the problems in the prior art, the present application aims to provide a sulfur recovery tail gas dust removal, desulfurization and denitrification integrated system and method, which integrally removes dust, desulfurizes and denitrifies the sulfur recovery tail gas, does not consume water in the process, and the byproduct is easy to clean, thereby improving the treatment effect of the sulfur recovery tail gas.

[0006] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions.

[0007] In a first aspect, the application discloses a sulfur recovery tail gas dust removal, desulfurization and denitrification integrated system, which comprises a pretreatment device, a fixed-bed dry desulfurization device, an SCR denitrification reactor and an induced draft fan; the pretreatment device is provided with a first gas inlet on the upper part of the side wall and a first gas outlet close to the lower part of the side wall; the fixed-bed dry desulfurization device is provided with a second gas inlet on the lower part of the side wall and a second gas outlet close to the upper part of the side wall; the SCR denitrification reactor is provided with a third gas inlet on the upper part and a third gas outlet on the lower part; the first gas outlet of the pretreatment device is connected with the second gas inlet of the fixed-bed dry desulfurization device, the second gas outlet of the fixed-bed dry desulfurization device is connected with the third gas inlet of the SCR denitrification reactor, and the third gas outlet of the SCR denitrification reactor is connected with the gas inlet of the induced draft fan; the pretreatment device is used for removing particulate dust in the sulfur recovery tail gas; the fixed-bed dry desulfurization device is used for desulfurizing the tail gas after the dust removal and removing sulfur dioxide in the tail gas; and the SCR denitrification reactor is used for denitrifying the tail gas after the dust removal and desulfurization and removing nitrogen oxides in the tail gas.

[0008] Preferably, the pretreatment device comprises a first vertical cylinder, the first vertical cylinder is provided with the first gas inlet on the upper part of the left wall and the first gas outlet on the lower part of the right wall; the first vertical cylinder is provided with a baffle plate parallel to the right wall of the first vertical cylinder, a first filter material bin and a second filter material bin filled with filter material, the left end of the first filter material bin is connected with the left wall of the first vertical cylinder, the left end of the second filter material bin is connected with the left wall of the first vertical cylinder, the right end of the first filter material bin is connected with the baffle plate, the right end of the second filter material bin is connected with the baffle plate, and the first filter material bin, the second filter material bin and the baffle plate form a closed space; a first airflow channel is formed between the first filter material bin and the front wall of the first vertical cylinder, a second airflow channel is formed between the second filter material bin and the rear wall of the first vertical cylinder, and a third airflow channel is formed between the baffle plate and the right wall of the first vertical cylinder, and the first airflow channel, the second airflow channel and the third airflow channel are connected with each other; the tail gas enters the closed space from the first gas inlet, passes through the first filter material bin or the second filter material bin and is discharged from the first gas outlet along the airflow channel.

[0009] Further preferably, the top end of the filter material bin is provided with a filter material feeding port, and the bottom is provided with a filter material discharging port; the filter material is granular calcium-based filter material with a porous structure.

[0010] Preferably, the fixed-bed dry desulfurization device comprises a second vertical cylinder and a desulfurizing agent, the desulfurizing agent is granular calcium hydroxide; the middle part of the second vertical cylinder is provided with a desulfurizing agent fixed bed, the desulfurizing agent is placed on the desulfurizing agent fixed bed; the upper part of the desulfurizing agent fixed bed is provided with a distribution plate, and the lower part of the desulfurizing agent fixed bed is a funnel-shaped bin, the funnel-shaped bin wall is provided with uniformly distributed air permeable holes; the top of the second vertical cylinder is provided with a desulfurizing agent feeding port, the lower part of the desulfurizing agent fixed bed is provided with a desulfurizing agent discharging port, and the desulfurizing agent feeding port and the desulfurizing agent discharging port are provided with covers; the lower part of the sidewall of the second vertical cylinder is provided with the second gas inlet, and the second gas outlet is arranged on the sidewall of the second vertical cylinder below the distribution plate.

[0011] Further preferably, a plurality of downwardly extending vertical pipes are uniformly distributed on the distribution plate, the lower ends of the vertical pipes extend below the second gas outlet, and the vertical pipes are used for uniformly distributing the desulfurizing agent on the desulfurizing agent fixed bed.

[0012] Preferably, the SCR denitration reactor comprises a third vertical cylinder and a reducing agent releasing device; the reducing agent nozzle of the reducing agent releasing device extends from the third vertical cylinder inwardly close to the upper end, and a denitration catalyst assembly is arranged in the middle part of the third vertical cylinder; the top of the third vertical cylinder is provided with the third gas inlet, and the bottom of the third vertical cylinder is provided with the third gas outlet; the denitration catalyst assembly is a corrugated plate type catalyst assembly, the corrugated plate type catalyst assembly comprises a substrate and a catalyst adhered to the substrate, the substrate is glass fiber, and the catalyst is a medium-temperature vanadium-titanium denitration catalyst; the third gas inlet is further provided with a flue gas flow distributor.

[0013] In a second aspect, an integrated method for dust removal, desulfurization and denitration of sulfur recovery tail gas comprises the following steps:

[0014] Step 1: introducing the sulfur recovery tail gas into the first gas inlet of the pretreatment device, and removing the particulate matters in the tail gas by filtering and absorbing;

[0015] Step 2: introducing the tail gas after removal of the particulate matters into the fixed-bed dry desulfurization device, and removing the sulfur dioxide in the tail gas by reaction with the desulfurizing agent;

[0016] Step 3: introducing the tail gas after desulfurization into the SCR denitration reactor, and removing the nitrogen oxides under the action of the reducing agent and the denitration catalyst;

[0017] Step 4: discharging the sulfur recovery tail gas after denitration by the induced draft fan.

[0018] Preferably, in step 3, the reducing agent is liquid ammonia or ammonia gas, and the flow of the liquid ammonia or ammonia gas is adjusted and controlled by the reducing agent releasing device.

[0019] Preferably, in step 2, the specific method for removing the sulfur dioxide is:

[0020] The sulfur recovery tail gas entraining water vapor is contacted with the desulfurizer bed, and the sulfur dioxide in the sulfur recovery tail gas reacts with the particulate calcium hydroxide desulfurizer as follows:

[0021] Ca(OH)2+SO2→CaSO3·1 / 2H2O+1 / 2H2O

[0022] CaSO3·1 / 2H2O+1 / 2O2+3 / 2H2O→CaSO4·2H2O

[0023] The sulfur dioxide reacts with the particulate calcium hydroxide desulfurizer to finally generate CaSO4·2H2O, and is removed from the sulfur recovery tail gas.

[0024] Preferably, in the step 3, the specific method for removing the nitrogen oxides is as follows:

[0025] Under the catalysis of the denitration catalyst, the reducing agent reacts with the nitrogen oxides in the sulfur recovery tail gas as follows:

[0026] 4NO+4NH3→4N2+6H2O

[0027] 2NO2+4NH3+O2→3N2+6H2O

[0028] The nitrogen oxides NO or NO2 are converted into N2 and H2O in the SCR denitration reactor, and are removed from the sulfur recovery tail gas.

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] The sulfur recovery tail gas dust removal, desulfurization and denitration integrated system integrates the dust removal, desulfurization and denitration in one system, and performs integrated dust removal, desulfurization and denitration collaborative processing on the sulfur recovery tail gas, thereby improving the processing effect on the sulfur recovery tail gas.

[0031] The sulfur recovery tail gas dust removal, desulfurization and denitration integrated method has the following advantages: the desulfurization process does not consume water, the byproduct is easy to clean, and the system is less affected; the denitration process can accurately control the reducing agent dosage, thereby improving the denitration effect. In addition, the sulfur recovery tail gas dust removal, desulfurization and denitration integrated method recycles the waste desulfurizer and uses it as the filler of the pretreatment device to remove the carbonyl sulfur and inorganic sulfur in the sulfur recovery tail gas, thereby improving the purification effect and economic benefits. BRIEF DESCRIPTION OF DRAWINGS

[0032] The present application will be further described in detail below in combination with the drawings and specific embodiments.

[0033] Figure 1 It is a schematic diagram of the sulfur recovery tail gas dust removal, desulfurization and denitration integrated system.

[0034] Figure 2 It is a top view of the pretreatment device.

[0035] Figure 3 is a front view of the pretreatment device;

[0036] Figure 4 is a left view of the pretreatment device;

[0037] The drawing identification: 1. Pretreatment device, 2. Fixed bed dry desulfurization device, 3. SCR denitration reactor, 4. Induced draft fan, 11. First vertical cylinder, 12. First filter material bin, 13. Cavity, 14. Second filter material bin, 15. Filter material feeding port, 16. Filter material discharging port, 17. Baffle, 21. Second vertical cylinder, 22. Desulfurizer, 23. Desulfurizer feeding port, 24. Desulfurizer discharging port, 25. Desulfurizer fixed bed, 26. Distributor plate, 27. Standpipe, 31. Third vertical cylinder, 32. Spray hole, 33. Denitration catalyst assembly, 34. Flue gas flow equalizer. DETAILED DESCRIPTION

[0038] The embodiments of the present application will be described in detail below with reference to the examples, but those skilled in the art will understand that the following examples are only for illustration of the present application and should not be regarded as limiting the scope of the present application.

[0039] (I) Reference Figure 1 , the schematic diagram of the sulfur recovery tail gas dust removal desulfurization and denitration integrated system of the present application. A sulfur recovery tail gas dust removal desulfurization and denitration integrated system, comprising a pretreatment device 1, a fixed bed dry desulfurization device 2, an SCR denitration reactor 3 and an induced draft fan 4; the pretreatment device 1 has a first gas inlet at the upper part of the side wall and a first gas outlet near the lower part of the side wall; the fixed bed dry desulfurization device 2 has a second gas inlet at the lower part of the side wall and a second gas outlet near the upper part of the side wall; the SCR denitration reactor 3 has a third gas inlet at the upper part and a third gas outlet at the lower part; the first gas outlet of the pretreatment device 1 is connected with the second gas inlet of the fixed bed dry desulfurization device 2, and the second gas outlet of the fixed bed dry desulfurization device 2 is connected with the third gas inlet of the SCR denitration reactor 3; the gas inlet of the induced draft fan 4 is connected with the third gas outlet of the SCR denitration reactor 3; the pretreatment device 1 is used for removing particulate matter dust in the sulfur recovery tail gas; the fixed bed dry desulfurization device 2 is used for desulfurizing the tail gas after removing the dust to remove sulfur dioxide in the tail gas; the SCR denitration reactor 3 is used for denitration of the tail gas after removing the dust and desulfurization to remove nitrogen oxides in the tail gas.

[0040] Typical sulfur recovery tail gas, pollutant concentration: sulfur dioxide 200-350 mg / Nm 3 , nitrogen oxides 50-240 mg / Nm 3 , particulate matter 10-20 mg / Nm 3, temperature 280-300℃; the sulfur recovery tail gas contains about 12% water vapor; during maintenance, the sulfur recovery tail gas may contain a small amount of sulfur impurities.

[0041] Reference Figure 2 , Figure 3 and Figure 4 wherein, Figure 2 is a top view of the pretreatment device; Figure 3 is a front view of the pretreatment device; Figure 4 is a left view of the pretreatment device. The pretreatment device 1 comprises a first vertical cylinder 11, the first vertical cylinder 11 is provided with a first gas inlet on the upper part of the left wall and a first gas outlet on the lower part of the right wall; the first vertical cylinder 11 is provided with a baffle plate 17 parallel to the right wall of the first vertical cylinder 11 and a first filter material bin 12 and a second filter material bin 14 filled with filter material, the left end of the first filter material bin 12 is connected with the left wall of the first vertical cylinder 11, the left end of the second filter material bin 14 is connected with the left wall of the first vertical cylinder 11, the right end of the first filter material bin 12 is connected with the baffle plate 17, the right end of the second filter material bin 14 is connected with the baffle plate 17, the first filter material bin 12, the second filter material bin 14 and the baffle plate 17 form a closed space 13; a first gas flow channel is formed between the first filter material bin 12 and the front wall of the first vertical cylinder 11, a second gas flow channel is formed between the second filter material bin 14 and the rear wall of the first vertical cylinder 11, and a third gas flow channel is formed between the baffle plate 17 and the right wall of the first vertical cylinder 11, the first gas flow channel, the second gas flow channel and the third gas flow channel are connected with each other; the tail gas enters the closed space 13 from the first gas inlet, passes through the first filter material bin 12 or the second filter material bin 14, and is discharged from the first gas outlet along the gas flow channel.

[0042] The top end of the filter material bin 12 is provided with a filter material charging port 15 and the bottom is provided with a filter material discharging port 16 for adding or replacing filter material, so that the filter material can be quickly replaced online. The filter material is granular calcium-based filter material with a porous structure, such as calcium sulfate and calcium carbonate. The filter material filters particulate matters in the sulfur recovery tail gas, such as carbonyl sulfide and inorganic sulfur; when the sulfur recovery device is restarted after maintenance, the filter material can also filter a large amount of sulfur recovery tail gas containing high-concentration elemental sulfur in a short time.

[0043] The fixed-bed dry desulfurization device 2 comprises a second vertical cylinder 21 and a desulfurizing agent 22, the desulfurizing agent 22 is granular calcium hydroxide; the desulfurizing agent 22 can remove sulfur dioxide in the sulfur recovery tail gas and also has a dust filtering effect, which can reduce the particulate matter concentration in the original flue gas; the deactivated waste desulfurizing agent can be used as filter material of the pretreatment device 1, realizing waste treatment with waste and saving resources. The desulfurizing agent can also maintain a small temperature drop of the flue gas, providing temperature conditions for the subsequent SCR denitration reactor. In this embodiment, the temperature drop of the fixed bed is not more than 20℃, and the fixed-bed dry desulfurization device 2 can operate reliably when the gas volume and pollutant concentration of the sulfur recovery tail gas are within 50%-150% of the set value.

[0044] The second vertical cylinder 21 is provided with a desulfurizer fixed bed 25 in the middle, and the desulfurizer 22 is placed on the desulfurizer fixed bed 25; the desulfurizer fixed bed 25 is provided with a distribution plate 26 at the upper part, and a plurality of vertical pipes 27 extending downward are uniformly distributed on the distribution plate 26, and the lower ends of the vertical pipes 27 extend to below the second gas outlet, for uniformly distributing the desulfurizer on the desulfurizer fixed bed; the lower part of the desulfurizer fixed bed 25 is a funnel-shaped bin, and the bin wall is provided with uniformly distributed air permeable holes; the second vertical cylinder is provided with a desulfurizer feeding port 23 at the top, and a desulfurizer discharging port 24 is arranged at the lower part of the desulfurizer fixed bed 25, for adding desulfurizer and replacing the deactivated waste desulfurizer; the desulfurizer feeding port and the desulfurizer discharging port are provided with covers; the second gas inlet is arranged at the lower part of the side wall of the second vertical cylinder 21, and the second gas outlet is arranged on the cylinder wall of the second vertical cylinder 21 at the lower part of the distribution plate 26.

[0045] The SCR denitration reactor 3 comprises a third vertical cylinder 31 and a reducing agent releasing device; the reducing agent nozzle of the reducing agent releasing device extends from the third vertical cylinder 31 inwardly from the position close to the upper end, and a denitration catalyst assembly is arranged in the middle of the third vertical cylinder 31; after the reducing agent is sprayed out by the nozzle, the nitrogen oxides are removed under the catalysis of the denitration catalyst assembly; the third gas inlet is arranged at the top of the third vertical cylinder 31, and the third gas outlet is arranged at the bottom; the denitration catalyst assembly is a corrugated plate type catalyst assembly, which comprises a base material and a catalyst adhered to the base material; the base material is glass fiber, and the catalyst is a medium-temperature vanadium-titanium denitration catalyst; a flue gas flow equalizer 34 is further arranged in the third gas inlet, for uniformly entering the tail gas into the SCR denitration reactor 3.

[0046] The sulfur recovery tail gas dust removal, desulfurization and denitration integrated system has good adaptability to the parameter changes of the sulfur recovery device incinerator waste gas and good treatment effect.

[0047] (II) A sulfur recovery tail gas dust removal, desulfurization and denitration integrated method, comprising the following steps:

[0048] Step 1: The sulfur recovery tail gas is connected to the first gas inlet of the pretreatment device, and the particulate matters in the tail gas are removed by filtering and absorbing.

[0049] The sulfur recovery tail gas discharged from the sulfur recovery tail gas incinerator enters the pretreatment device 1, and the particulate matters such as elemental sulfur, carbonyl sulfur and inorganic sulfur in the sulfur recovery tail gas are removed.

[0050] Step 2: The tail gas after removing the particulate matters enters the fixed bed dry desulfurization device, and reacts with the desulfurizer to remove the sulfur dioxide in the tail gas.

[0051] The sulfur recovery tail gas discharged from the pretreatment device enters the fixed-bed dry desulfurization device. The sulfur recovery tail gas entraining water vapor contacts with the desulfurizer bed, and the sulfur dioxide in the sulfur recovery tail gas reacts with the particulate calcium hydroxide desulfurizer as follows:

[0052] Ca(OH)2+SO2→CaSO3·1 / 2H2O+1 / 2H2O

[0053] CaSO3·1 / 2H2O+1 / 2O2+3 / 2H2O→CaSO4·2H2O

[0054] The sulfur dioxide reacts with the particulate calcium hydroxide desulfurizer to generate CaSO4·2H2O, which is removed from the sulfur recovery tail gas. After the desulfurization treatment, the concentration of sulfur dioxide is reduced to the emission concentration, reaching the emission standard. At the same time, the desulfurizer can further remove the particulate matter in the sulfur recovery tail gas, further reducing the concentration of particulate matter in the sulfur recovery tail gas.

[0055] In addition, the spent desulfurizer deactivated after absorbing sulfur dioxide is sent to the pretreatment device for use as filter material, realizing waste utilization.

[0056] Step 3, the tail gas after desulfurization treatment enters the SCR denitration reactor, and nitrogen oxides are removed under the action of a reducing agent and a denitration catalyst;

[0057] After the desulfurized sulfur recovery tail gas enters the SCR denitration reactor, the reducing agent is sprayed from the nozzle inside the SCR denitration reactor, and the flow rate of the reducing agent is adjusted and controlled by a reducing agent release device. In this embodiment, the reducing agent release device is a micro-flow ammonia spraying device, and the reducing agent is liquid ammonia or ammonia gas. Under the catalysis of the denitration catalyst, the reducing agent reacts with the nitrogen oxides in the sulfur recovery tail gas as follows:

[0058] 4NO+4NH3→4N2+6H2O

[0059] 2NO2+4NH3+O2→3N2+6H2O

[0060] The nitrogen oxides NO or NO2 are converted into N2 and H2O in the SCR denitration reactor, and are removed from the sulfur recovery tail gas. After the denitration treatment, the concentration of nitrogen oxides is reduced to the emission concentration, reaching the emission standard.

[0061] Step 4, the sulfur recovery tail gas after denitration treatment is discharged by an induced draft fan.

[0062] The concentration data of various pollutants in the sulfur recovery tail gas before and after treatment are shown in Table 1. It can be seen that the nitrogen oxides, sulfur dioxide and particulate matter after treatment all meet the emission standard.

[0063] Table 1 Concentration of pollutants in sulfur recovery tail gas before and after treatment, unit: mg / Nm 3

[0064] pollutants before treatment after treatment emission standards nitrogen oxides 70 12 ≤50 sulfur dioxide 200 9 ≤35 particulate matter 10 2.2 ≤10

[0065] While the application has been described in connection with specific embodiments thereof, it will be understood that it is capable of modification and variation and is limited only by the claims.

Claims

1. A sulfur recovery tail gas dedusting, desulfurization and denitrification integrated system, characterized in that: The application relates to a flue gas treatment device, which comprises a pretreatment device (1), a fixed-bed dry desulfurization device (2), an SCR denitration reactor (3) and an induced draft fan (4); the pretreatment device (1) is provided with a first air inlet on the upper part of the side wall and a first air outlet close to the lower part of the side wall; the fixed-bed dry desulfurization device (2) is provided with a second air inlet on the lower part of the side wall and a second air outlet close to the upper part of the side wall; the upper part of the SCR denitration reactor (3) is provided with a third air inlet, and the lower part is provided with a third air outlet; the first air outlet of the pretreatment device (1) is connected with the second air inlet of the fixed-bed dry desulfurization device (2), the second air outlet of the fixed-bed dry desulfurization device (2) is connected with the third air inlet of the SCR denitration reactor (3), and the air inlet of the induced draft fan (4) is connected with the third air outlet of the SCR denitration reactor (3); the pretreatment device (1) is used for removing particulate matters and dust in sulfur recovery tail gas; the fixed-bed dry desulfurization device (2) is used for desulfurizing the tail gas after the dust is removed, and removing sulfur dioxide in the tail gas; the SCR denitration reactor (3) is used for denitration of the tail gas after the dust and sulfur are removed, and removing nitrogen oxides in the tail gas; The pretreatment device (1) comprises a first vertical cylinder (11), the first vertical cylinder (11) is provided with the first air inlet on the upper part of the left wall and the first air outlet on the lower part of the right wall; the first vertical cylinder (11) is provided with a baffle (17) parallel to the right wall of the first vertical cylinder (11), a first filter material bin (12) and a second filter material bin (14) filled with filter materials, the left end of the first filter material bin (12) is connected with the left wall of the first vertical cylinder (11), the left end of the second filter material bin (14) is connected with the left wall of the first vertical cylinder (11), the right end of the first filter material bin (12) is connected with the baffle (17), the right end of the second filter material bin (14) is connected with the baffle (17), the first filter material bin (12), the second filter material bin (14) and the baffle (17) form a closed space (13); a first airflow channel is formed between the first filter material bin (12) and the front wall of the first vertical cylinder (11), a second airflow channel is formed between the second filter material bin (14) and the rear wall of the first vertical cylinder (11), and a third airflow channel is formed between the baffle (17) and the right wall of the first vertical cylinder (11), the first airflow channel, the second airflow channel and the third airflow channel are communicated with each other; the tail gas enters the closed space (13) from the first air inlet, passes through the first filter material bin (12) or the second filter material bin (14) and is discharged from the first air outlet along the airflow channel. The fixed bed dry desulfurization device (2) comprises a second vertical cylinder (21) and a desulfurizer (22), the desulfurizer (22) is granular calcium hydroxide; the second vertical cylinder (21) is provided with a desulfurizer fixed bed (25) in the middle part, the desulfurizer (22) is placed on the desulfurizer fixed bed (25); the upper part of the desulfurizer fixed bed (25) is provided with a distribution plate (26), and the lower part of the desulfurizer fixed bed (25) is a funnel-shaped bin, the funnel-shaped bin wall is provided with uniformly distributed air permeable holes; the second vertical cylinder top is provided with a desulfurizer feeding port (23), the lower part of the desulfurizer fixed bed (25) is provided with a desulfurizer discharge port (24), and the desulfurizer feeding port and the desulfurizer discharge port are provided with covers; the lower part of the second vertical cylinder (21) side wall is provided with the second gas inlet, and the second gas outlet is arranged on the second vertical cylinder (21) cylinder wall below the distribution plate (26); The SCR denitration reactor (3) comprises a third vertical cylinder (31) and a reducing agent releasing device; the reducing agent nozzle of the reducing agent releasing device penetrates from the inside of the third vertical cylinder (31) close to the upper end, and the third vertical cylinder (31) is provided with a denitration catalyst assembly in the middle part; the third vertical cylinder (31) is provided with the third gas inlet at the top and the third gas outlet at the bottom; the denitration catalyst assembly is a corrugated plate type catalyst assembly, the corrugated plate type catalyst assembly comprises a substrate and a catalyst adhered to the substrate, the substrate is glass fiber, and the catalyst is a medium-temperature vanadium-titanium denitration catalyst; the third gas inlet is further provided with a flue gas flow equalizer (34).

2. The sulfur recovery tail gas dedusting, desulfurization and denitrification integrated system according to claim 1, characterized in that, The first filter bin (12) is provided with a filter feeding port (15) at the top end and a filter discharge port (16) at the bottom, and the filter is granular calcium-based filter material with a porous structure.

3. The sulfur recovery tail gas dedusting, desulfurization and denitrification integrated system according to claim 1, characterized in that, A plurality of downward extending vertical pipes (27) are uniformly distributed on the distribution plate (26), the lower end of the vertical pipe (27) extends below the second gas outlet, and the vertical pipe (27) is used for uniformly distributing the desulfurizer on the desulfurizer fixed bed layer.

4. A sulfur recovery tail gas dedusting, desulfurization and denitrification integrated method, characterized in that, The method is based on the sulfur recovery tail gas dust removal, desulfurization and denitration integrated system according to any one of claims 1 to 3, and comprises the following steps: Step 1, the sulfur recovery tail gas is connected to the first gas inlet of the pretreatment device, and the particulate matters in the tail gas are removed by filtering and absorbing through the filter; Step 2, the tail gas after removing the particulate matters enters the fixed bed dry desulfurization device, and reacts with the desulfurizer to remove sulfur dioxide in the tail gas; Step 3, the tail gas after desulfurization treatment enters the SCR denitration reactor, and the nitrogen oxides are removed under the action of the reducing agent and the denitration catalyst; Step 4, the sulfur recovery tail gas after denitration treatment is discharged through the induced draft fan.

5. The sulfur recovery tail gas dedusting, desulfurization and denitrification integrated method according to claim 4, characterized in that, In step 3, the reducing agent is liquid ammonia or ammonia gas, and the flow of the liquid ammonia or ammonia gas is adjusted and controlled through the reducing agent releasing device.

6. The sulfur recovery tail gas dedusting, desulfurization and denitrification integrated method according to claim 4, characterized in that, In step 2, the specific method for removing sulfur dioxide is as follows: After the sulfur recovery tail gas containing water vapor contacts with the desulfurizer bed, the sulfur dioxide in the tail gas reacts with the granular calcium hydroxide desulfurizer as follows: Ca (OH) 2+ SO2 → CaSO3·1 / 2H2O + 1 / 2H2O CaSO3·1 / 2H2O + 1 / 2O2 + 3 / 2H2O→ CaSO4·2H2O Sulfur dioxide reacts with the particulate calcium hydroxide desulfurizer to ultimately produce CaSO4·2H2O, removing sulfur from the sulfur recovery tail gas.

7. The sulfur recovery tail gas dedusting, desulfurization and denitrification integrated method according to claim 4, characterized in that, The specific method for removing nitrogen oxides in step 3 is: Under the catalysis of the denitration catalyst, the reducing agent reacts with the nitrogen oxides in the sulfur recovery tail gas as follows: 4NO + 4NH3→ 4N2 + 6H2O 2NO2 + 4NH3 + O2→ 3N2 + 6H2O The nitrogen oxides NO or NO2 are converted into N2 and H2O in the SCR denitration reactor, removing sulfur from the sulfur recovery tail gas.

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