A device and process for flue gas activated coke dry desulfurization

Abstract

The present invention discloses a device and process for flue gas activated coke dry desulfurization. The powdered activated coke two-stage fluidized bed flue gas dry desulfurization device comprises a two-stage fluidized bed desulfurization device, and the two-stage fluidized bed desulfurization device is provided with a discharge port for activated coke after desulfurization, a flue gas conveying inlet, a fluidized flue gas inlet, a dense phase return port, a powdered activated coke feeding port and a flue gas outlet after desulfurization. The present invention can be applied to the technical field of flue gas dry desulfurization. Compared with the existing flue gas activated coke dry desulfurization device, the present invention uses amorphous fine powdered activated coke as an adsorbent, and a two-stage fluidized bed dry desulfurization device with a circulating return device as a desulfurization device, which is conducive to reducing the cost of the desulfurization adsorbent, and greatly improving the utilization efficiency of the activated coke adsorbent and the removal efficiency of sulfur dioxide.

Description

Technical Field

[0001] The present invention relates to a device and process for flue gas activated coke dry desulfurization, and in particular to a powdered activated coke two-stage fluidized bed flue gas dry desulfurization device, belonging to the technical field of flue gas desulfurization. Background Art

[0002] Coal occupies an important position in my country's primary energy structure. Sulfur dioxide and nitrogen oxide pollutants exist in the flue gas generated during the coal combustion process. The pollutants in the flue gas must be removed to meet the standards before the flue gas can be discharged. At present, the main methods for removing sulfur dioxide from flue gas are wet desulfurization, semi-dry desulfurization and dry desulfurization. Among them, limestone-gypsum wet and semi-dry flue gas desulfurization have been widely promoted due to their simple process, cheap and easy to obtain desulfurization raw materials, and high desulfurization efficiency. However, some problems have also been brought about: 1) The large water consumption leads to large wastewater discharge, and the problem of wastewater treatment has become increasingly prominent; 2) Excessive exploitation of limestone resources has caused ecological damage; 3) The quality of the by-product desulfurization gypsum is low, and the secondary utilization value is not high, resulting in a large amount of gypsum being discarded or landfilled, which is easy to cause secondary pollution.

[0003] The activated coke dry flue gas desulfurization technology is one of the emerging technologies for flue gas desulfurization in recent years. It has the advantages of no wastewater discharge, sulfur resource utilization and multiple pollutants (SO2, NO x , Hg and dioxins, etc.) can be removed in an integrated manner. At present, activated coke dry flue gas desulfurization has been used for the purification of flue gas in the steel industry, flue gas from non-ferrous metal smelting, sulfuric acid tail gas, and flue gas from environmental collection. The activated coke flue gas desulfurization device that has been put into industrial application mainly uses a moving bed as a desulfurization reactor, and the main problems are as follows: 1) The desulfurizer is a columnar shaped activated coke with a diameter of 5 to 9 mm. Due to the high preparation cost, the price of each ton of activated coke is as high as 6,000 to 12,000 yuan / ton, resulting in a high operating cost of the moving bed activated coke dry desulfurization technology; 2) Due to the large size of activated coke particles, it is difficult for the molecules of gaseous pollutants to diffuse into the interior of the activated coke particles, resulting in low utilization of the inner surface of the activated coke, and the adsorption performance of the activated coke particles cannot be fully utilized; 3) The moving bed desulfurization reactor device is large in size, occupies a large area, and has high investment in supporting equipment. Summary of the invention

[0004] The present invention aims to provide a device and process for dry desulfurization of flue gas with activated coke, which is essentially an adsorption desulfurization device for granular amorphous activated coke, so as to solve the problems of large footprint of desulfurization devices, high cost of activated coke and low utilization of particle adsorption performance of existing shaped activated coke desulfurization technology.

[0005] The present invention provides a flue gas activated coke dry desulfurization device, comprising a powdered activated coke two-stage fluidized bed desulfurization device, the fluidized bed desulfurization device is provided with a cylinder, a flue gas distribution cylinder, a discharge device, a flue gas air distribution device, a return device, and a feeding device; the cylinder is also provided with a flue gas desulfurization post-activated coke discharge port, a conveying flue gas inlet, a fluidized flue gas inlet, a dense phase section return port, a powdered activated coke feeding port, and a flue gas post-desulfurization outlet;

[0006] The powdered activated coke two-stage fluidized bed desulfurization device comprises a cylinder, which comprises a discharge device, a flue gas air distribution device, a dense phase section, a gradually contracting section and a dilute phase section which are sequentially connected from bottom to top;

[0007] The two-stage fluidized bed desulfurization device for powdered activated coke comprises a flue gas distribution cylinder, which is connected to the flue gas inlet and is also connected to the flue gas air distribution device and the central pipe of the cylinder; the undesulfurized flue gas enters the flue gas distribution cylinder from the flue gas inlet and is divided into two gases, one of which enters the flue gas air distribution device as fluidizing gas, and the other enters the central pipe of the discharge device as conveying gas;

[0008] The powdered activated coke two-stage fluidized bed desulfurization device comprises a discharge device, which comprises a central tube and a discharge collection hopper, wherein a flue gas inlet on the side wall of the central tube is connected to a flue gas distribution cylinder through a pipeline, the bottom of the central tube is connected to the discharge collection hopper, and the top of the central tube extends to a flue gas air distribution device in the powdered activated coke two-stage fluidized bed desulfurization device;

[0009] The powdered activated coke two-stage fluidized bed desulfurization device comprises a flue gas air distribution device, the flue gas air distribution device is provided with a truncated cone-shaped distribution plate and an air chamber, the air chamber is connected with the flue gas distribution cylinder through a pipeline, the truncated cone-shaped distribution plate comprises an upper table and a lower table, the lower table of the truncated cone-shaped distribution plate is connected with the central tube, the upper table of the truncated cone-shaped distribution plate is connected with the dense phase section, and a fluidizing nozzle is provided on the truncated cone-shaped distribution plate, and the nozzle is connected with the air chamber and the inside of the fluidized bed desulfurization device;

[0010] The two-stage fluidized bed desulfurization device for powdered activated coke includes a return device, which includes a collecting hopper, a feeding bin and an N-type return valve. The powdered activated coke is transported to the feeding bin through an activated coke supply system. The bottom of the feeding bin is connected to the top of the collecting hopper through a pipeline equipped with a metering device and a flow control device. The collecting hopper is connected to the return port of the dense phase section through a pipeline equipped with an N-type return valve.

[0011] The two-stage fluidized bed desulfurization device for powdered activated coke comprises a feeding device, which is provided with a powdered activated coke supply port. After the amorphous powdered activated coke used for flue gas desulfurization is added into the feeding device through the powdered activated coke supply port, the amorphous powdered activated coke is connected to the powdered activated coke feeding port of the two-stage fluidized bed desulfurization device for powdered activated coke through a pipeline. A metering device and a star-shaped feeder are provided on the pipeline to respectively record and control the flow rate of the powdered activated coke.

[0012] Furthermore, a discharge port for desulfurized activated coke is provided at the lower part of the discharge collection hopper of the discharge device, a return port for the dense phase section is provided on the side wall of the dense phase section, a feeding port for powdered activated coke is provided on the side wall of the dilute phase section, and a flue gas outlet for desulfurized activated coke is provided at the top of the dilute phase section.

[0013] Furthermore, the diffusion angle θ formed by the diameter of the lower table of the truncated cone distribution plate of the flue gas distribution device and the waistline of the truncated cone is 45~60°, the conveying flue gas inlet is arranged on the side wall of the central tube of the discharge device, and the fluidizing flue gas inlet is arranged on the side wall of the air chamber of the flue gas distribution device.

[0014] A tapered section is arranged in the middle of a two-stage fluidized bed desulfurization device for powdered activated coke, and the tapered section connects a dense phase section and a dilute phase section. The ratio of the diameter of the lower dense phase section to the diameter of the upper dilute phase section is 1:(2-4), and the ratio of the height of the lower dense phase section to the height of the upper dilute phase section is 1:(0.5-2). The tapered section is truncated cone-shaped, including an upper table surface and a lower table surface. The diffusion angle α formed by the diameter of the lower table surface and the waistline of the truncated cone is 45-65°.

[0015] The two-stage fluidized bed desulfurization device for powdered activated coke also includes a first-stage cyclone separator, which is connected to the desulfurization flue gas outlet through a pipeline, the powdered activated coke collected by the first-stage cyclone separator enters the collecting hopper through the pipeline, and the flue gas at the top outlet of the first-stage cyclone separator enters the second-stage cyclone separator; the powdered activated coke collected by the second-stage cyclone separator is collected and recycled, and the flue gas at the top outlet of the second-stage cyclone separator enters the bag dust collector; the bag dust collector is provided with a flue gas discharge pipeline after desulfurization and dust removal, the flue gas is discharged through the pipeline, and the powdered activated coke collected by the bag dust collector is recycled.

[0016] The present invention provides a process for dry desulfurization of flue gas with activated coke using the above-mentioned device, comprising the following steps: using amorphous fine powdered activated coke as an adsorbent, adding the amorphous powdered activated coke with a particle equivalent diameter of 0.5 to 1.0 mm into an activated coke feeding device through an activated coke supply system, and entering the dilute phase section of a two-stage fluidized bed desulfurization device for powdered activated coke after being controlled and metered by a star feeder and a metering device respectively, and falling into the dense phase section of the two-stage fluidized bed desulfurization device for powdered activated coke under the action of gravity, and the undesulfurized flue gas entering the flue gas separation cylinder is divided into two gases and respectively enters the dense phase section through the air chamber of a flue gas distribution device and a central tube, and due to the airflow formed by the flue gas, the powdered activated coke as an adsorbent is fully mixed and turbulent with the flue gas, presenting a polymerized fluidization, and the sulfur dioxide in the flue gas is fully absorbed by the activated coke. After the activated coke particles rise to the dilute phase section together with the flue gas, a part of the particles return to the dense phase section due to their own gravity due to the decrease in the flue gas velocity. This is conducive to further increasing the concentration of powdered activated coke particles in the bed layer in the dense phase section, while prolonging the time for the powdered or activated coke to participate in the adsorption desulfurization. The other part of the activated coke is carried out of the powdered activated coke two-stage fluidized bed desulfurization device along with the flue gas. The purified dust-containing flue gas passes through a primary cyclone separator, a secondary cyclone separator and a bag dust collector and is discharged to the next process. The powdered activated coke collected by the primary cyclone separator and part of the powdered activated coke in the feed bin are controlled by the N-type return valve in the return device and then enter the dense phase section of the powdered activated coke two-stage fluidized bed desulfurization device to participate in desulfurization, thereby further improving the desulfurization adsorption performance of the powdered activated coke. The single-set device of the flue gas activated coke dry desulfurization process of the present invention is suitable for flue gas operating conditions with a flow rate of 40,000-70,000 Nm 3 / h, the sulfur dioxide concentration in the inlet flue gas is ≤ 3000 mg / Nm 3 , dust concentration in flue gas ≤ 5 g / Nm 3 , the flue gas temperature is in the range of 120-160 ℃. The sulfur dioxide concentration in the treated flue gas is ≤ 35 mg / Nm 3 , which can meet the national requirements for ultra-low emission concentration of sulfur dioxide in flue gas of various industries.

[0017] Beneficial effects of the present invention:

[0018] Compared with the existing activated coke dry desulfurization device, the present invention uses amorphous fine powdered activated coke as the adsorbent and a two-stage fluidized bed dry desulfurization device with a circulating return device as the desulfurization device, which is beneficial to reducing the cost of the desulfurization adsorbent and greatly improving the utilization efficiency of the activated coke adsorbent and the removal efficiency of sulfur dioxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the device for flue gas activated coke dry desulfurization according to the present invention.

[0020] Figure 2 It is a structural schematic diagram of the flue gas air distribution device.

[0021] In the figure: 1. flue gas distribution cylinder; 2. discharge collection hopper; 3. central pipe; 4. flue gas air distribution device; 5. dense phase section; 6. tapering section; 7. dilute phase section; 8. feeding device; 9. feeding bin; 10. primary cyclone separator; 11. collecting hopper; 12. N-type return valve; 13. secondary cyclone separator; 14. bag filter; 15. air chamber; 16. distribution plate; 17. fluidizing nozzle; 18. fluidizing flue gas inlet; 19. conveying flue gas inlet; 20. flue gas inlet, 21. activated coke inlet, 22. feeding port, 23. flue gas outlet, 24. discharge port. DETAILED DESCRIPTION

[0022] The present invention provides a powdered activated coke two-stage fluidized bed flue gas dry desulfurization device and process. In order to make the purpose, technical scheme and effect of the present invention clearer, the scheme is further described through the following examples. The specific examples described in the present invention are only used to explain the present invention and are not used to limit the present invention.

[0023] Embodiment 1:

[0024] like Figure 1 and 2 As shown, a device for dry desulfurization of flue gas activated coke includes a two-stage fluidized bed desulfurization device for powdered activated coke, the fluidized bed desulfurization device is provided with a cylinder, a flue gas distribution cylinder 1, a discharge device, a flue gas air distribution device 4, a return device, and a feeding device 8; a discharge port for activated coke after flue gas desulfurization, a conveying flue gas inlet 19, a fluidized flue gas inlet 18, a dense phase return port, a powdered activated coke feeding port and a flue gas outlet after desulfurization.

[0025] The smoke distribution cylinder 1 is connected to the smoke inlet, and the smoke distribution cylinder 1 leads to the smoke air distribution device 4 and the central pipe 3 of the cylinder;

[0026] The powdered activated coke two-stage fluidized bed desulfurization device comprises a cylinder, which comprises a discharge device, a flue gas air distribution device 4, a dense phase section 5, a tapering section 6 and a dilute phase section 7 which are sequentially connected from bottom to top;

[0027] The two-stage fluidized bed desulfurization device for powdered activated coke comprises a flue gas separation cylinder 1. After the undesulfurized flue gas enters the flue gas separation cylinder 1 from the flue gas inlet, it is divided into two gases, one of which is used as fluidizing gas to enter the flue gas air distribution device 4, and the other is used as conveying gas to enter the central pipe 3 of the discharge device;

[0028] The discharge device includes a central tube 3 and a discharge collection hopper 2, the side wall of the central tube 3 is connected to the flue gas inlet and the flue gas cylinder 1 through a pipeline, the bottom of the central tube 3 is connected to the discharge collection hopper 2, and the top of the central tube 3 extends to the flue gas air distribution device 4 in the powdered activated coke two-stage fluidized bed desulfurization device;

[0029] The powdered activated coke two-stage fluidized bed desulfurization device comprises a flue gas air distribution device, the flue gas air distribution device 4 is provided with a truncated cone-shaped distribution plate 16 and an air chamber 15, the air chamber 15 is connected to the flue gas distribution cylinder 1 through a pipeline, the truncated cone-shaped distribution plate 16 comprises an upper table and a lower table, the lower table of the truncated cone-shaped distribution plate 16 is connected to the central tube 3, the upper table of the truncated cone-shaped distribution plate 16 is connected to the dense phase section 5, and a fluidizing nozzle 17 is provided on the truncated cone-shaped distribution plate 16, and the nozzle communicates with the air chamber and the inside of the fluidized bed desulfurization device;

[0030] The two-stage fluidized bed desulfurization device for powdered activated coke also includes a return device, which includes a collecting hopper 11, a feeding bin 9 and an N-type return valve 12. The powdered activated coke is transported to the feeding bin 9 through an activated coke supply system. The bottom of the feeding bin 9 is connected to the top of the collecting hopper 11 through a pipeline equipped with a metering device and a flow control device. The collecting hopper 11 is connected to the return port of the dense phase section through a pipeline equipped with an N-type return valve 12.

[0031] The two-stage fluidized bed desulfurization device for powdered activated coke also includes a feeding device, which is provided with a powdered activated coke inlet 21. After the amorphous powdered activated coke used for flue gas desulfurization is added to the feeding device through the powdered activated coke supply port, it is connected to the powdered activated coke feeding port of the two-stage fluidized bed desulfurization device for powdered activated coke through a pipeline. A metering device and a star-shaped feeder are provided on the pipeline to respectively record and control the flow rate of the powdered activated coke.

[0032] A discharge port for desulfurized activated coke is provided at the lower part of the discharge collecting hopper 2 of the discharge device, a return port for the dense phase section 5 is provided on the side wall of the dense phase section 5, a feeding port for powdered activated coke is provided on the side wall of the dilute phase section 7, and a flue gas outlet for desulfurized activated coke is provided at the top of the dilute phase section 7.

[0033] Furthermore, the diffusion angle θ formed by the diameter of the lower surface of the truncated cone distribution plate 16 of the flue gas distribution device 4 and the waistline of the truncated cone is 45~60°, the conveying flue gas inlet 19 is arranged on the side wall of the central tube 3 of the discharge device, and the fluidizing flue gas inlet 18 is arranged on the side wall of the air chamber 15 of the flue gas distribution device.

[0034] A tapered section 6 is arranged in the middle of the two-stage fluidized bed desulfurization device for powdered activated coke, and the tapered section 6 connects the dense phase section 5 and the dilute phase section 7. The ratio of the diameter of the lower dense phase section 5 to the diameter of the upper dilute phase section 7 is 1:(2-4), and the ratio of the height of the lower dense phase section to the height of the upper dilute phase section is 1:(0.5-2).

[0035] The two-stage fluidized bed desulfurization device for powdered activated coke also includes a primary cyclone separator 10, which is connected to the desulfurization flue gas outlet through a pipeline. The powdered activated coke collected by the primary cyclone separator 10 enters a collecting hopper 11 through a pipeline, and the flue gas at the top outlet of the primary cyclone separator 10 enters a secondary cyclone separator 13; the powdered activated coke collected by the secondary cyclone separator 13 is collected and recycled, and the flue gas at the top outlet of the secondary cyclone separator 13 enters a bag dust collector 14; the bag dust collector 14 is provided with a flue gas discharge pipeline after desulfurization and dust removal, and the flue gas is discharged through the pipeline, and the powdered activated coke collected by the bag dust collector 14 is recycled.

[0036] The experimental detection methods used in the following examples are all conventional methods unless otherwise specified. The SO2 in the flue gas in the examples is analyzed and the data is recorded using an online flue gas analyzer. The initial concentration of SO2 in the flue gas and the concentration after the flue gas dry desulfurization of the present invention are measured, and the flue gas desulfurization efficiency can be obtained by calculation.

[0037] The activated coke used in the examples is commercially purchased powdered activated coke, and the particle equivalent diameter is 0.5-1 mm.

[0038] use Figure 1The flue gas activated coke dry desulfurization device shown in the figure carries out adsorption desulfurization treatment on the sulfur-containing flue gas, and the specific implementation process is as follows: first, fresh powdered activated coke particles are continuously loaded into the feeding device, the feeding bin and the collecting hopper, the discharge valve of the discharge collection hopper is closed, and then the sulfur-containing flue gas is introduced into the flue gas distribution cylinder, and the flow of the fluidized flue gas entering the flue gas air distribution device and the conveying flue gas entering the discharge device are adjusted respectively, and at the same time, the star feeder valve at the bottom of the feeding device is slowly opened to add granular activated coke to the dilute phase section, and gradually establish a stable operating material bed layer in a bubbling fluidized state, open the N-type return valve, and gradually enter a stable return cycle operation process. With the help of the disturbance of the airflow, the flue gas and the particles in the dense phase section are strongly mixed, and the gas-solid two-phase is fully contacted, resulting in the full absorption of SO2 in the flue gas. This gas-solid two-phase flow mechanism in the fluidized bed is very conducive to strengthening the mass transfer process between the gas-solid two-phase, can make full use of the adsorption capacity of activated coke, greatly improves the adsorption capacity of activated coke, and provides a fundamental guarantee for the efficient removal of SO2. When the working sulfur capacity of the activated coke in the bed is close to the saturated sulfur capacity, the flow rate of the flue gas is adjusted regularly to discharge this part of the activated coke into the discharge collection hopper, and then the discharge valve of the discharge collection hopper is regularly controlled to discharge it out of the system for regeneration and recycling. When the flue gas leaves the dense phase section and enters the dilute phase section through the tapering section, the gas velocity decreases, and it can contact with the fresh activated coke entering the dilute phase section from the feeding device again to undergo adsorption desulfurization reaction, further reducing the concentration of SO2 in the flue gas. Part of the activated coke that has not reached the saturated sulfur capacity enters the dense phase section by gravity to further participate in the desulfurization adsorption reaction, and the other part is carried by the flue gas to leave the dilute phase section of the fluidized bed and enter the first-stage cyclone separator to be captured and enter the collecting hopper. Together with the fresh activated coke continuously added to the feeding bin, it is controlled by the N-type return valve and returned to the dense phase section of the flue gas activated coke dry desulfurization device to undergo adsorption desulfurization reaction again. After the desulfurized flue gas leaves the first-stage cyclone separator, it enters the second-stage cyclone separator and the bag filter in turn to meet the emission standards.

[0039] Example 1

[0040] The diffusion angle α of the tapered section of the two-stage fluidized bed desulfurization device is 50°; the diffusion angle θ of the truncated cone distribution plate is 45°; the height of the dense phase section is 5 m and the diameter is 1 m; the height of the dilute phase section is 5 m and the diameter is 2.5 m. Sulfur-containing flue gas inlet composition (volume ratio) SO2: 1500 mg / Nm 3 ; Water vapor 10%; Oxygen: 6%; Carbon dioxide: 15%; The rest is N2; The inlet temperature of sulfur-containing flue gas is 120 ℃, and the dust concentration in the flue gas is ≤5 g / Nm 3 .

[0041] use Figure 1The flue gas activated coke dry desulfurization device shown in the figure performs adsorption desulfurization treatment on the sulfur-containing flue gas, and the desulfurization efficiency is ≥98%, and the SO2 concentration in the flue gas after desulfurization is ≤35 mg / Nm 3 .

[0042] Example 2

[0043] The diffusion angle α of the tapered section of the two-stage fluidized bed desulfurization device is 60°; the diffusion angle θ of the truncated cone distribution plate is 60°; the height of the dense phase section is 5 m and the diameter is 1 m; the height of the dilute phase section is 5 m and the diameter is 2 m. Sulfur-containing flue gas inlet composition (volume ratio) SO2: 5000 mg / Nm 3 ; Water vapor 10%; Oxygen: 6%; Carbon dioxide: 15%; The rest is N2; The inlet temperature of sulfur-containing flue gas is 150 ℃, and the dust concentration in the flue gas is ≤5 g / Nm 3 .

[0044] use Figure 1 After the flue gas activated coke dry desulfurization device shown in the figure carries out adsorption desulfurization treatment on the sulfur-containing flue gas, the desulfurization efficiency is ≥95%, and the SO2 concentration in the flue gas after desulfurization is ≤35 mg / Nm 3 .

[0045] The embodiments described above are only preferred embodiments of the present invention and are not intended to limit the present invention. For relevant technical personnel in the field, the present invention may have various modifications, improvements and variations without departing from the spirit and scope of the present invention. If these modifications, improvements and variations fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications, improvements and variations.

Claims

1. A flue gas activated coke dry desulfurization device, characterized in that: It comprises a two-stage fluidized bed desulfurization device for powdered activated coke, which is provided with a cylinder, a flue gas distribution cylinder, a discharge device, a flue gas air distribution device, a return device, and a feeding device; the cylinder is also provided with a discharge port for activated coke after flue gas desulfurization, a conveying gas inlet, a fluidized flue gas inlet, a dense phase return port, a powdered activated coke feeding port, and a flue gas outlet after desulfurization; The powdered activated coke two-stage fluidized bed desulfurization device comprises a cylinder, which comprises a discharge device, a flue gas air distribution device, a dense phase section, a gradually contracting section and a dilute phase section which are sequentially connected from bottom to top; The two-stage fluidized bed desulfurization device for powdered activated coke comprises a flue gas distribution cylinder, which is connected to the flue gas inlet and is also connected to the flue gas air distribution device and the central pipe of the cylinder; the undesulfurized flue gas enters the flue gas distribution cylinder from the flue gas inlet and is divided into two gases, one of which enters the flue gas air distribution device as fluidized flue gas, and the other enters the central pipe of the discharge device as conveying gas; The powdered activated coke two-stage fluidized bed desulfurization device comprises a discharge device, which comprises a central tube and a discharge collection hopper, wherein a flue gas inlet on the side wall of the central tube is connected to a flue gas distribution cylinder through a pipeline, the bottom of the central tube is connected to the discharge collection hopper, and the top of the central tube extends to a flue gas air distribution device in the powdered activated coke two-stage fluidized bed desulfurization device; The powdered activated coke two-stage fluidized bed desulfurization device comprises a flue gas air distribution device, the flue gas air distribution device is provided with a truncated cone-shaped distribution plate and an air chamber, the air chamber is connected with the flue gas distribution cylinder through a pipeline, the truncated cone-shaped distribution plate comprises an upper table and a lower table, the lower table of the truncated cone-shaped distribution plate is connected with the central tube, the upper table of the truncated cone-shaped distribution plate is connected with the dense phase section, and a fluidizing nozzle is provided on the truncated cone-shaped distribution plate, and the nozzle is connected with the air chamber and the inside of the fluidized bed desulfurization device; The powdered activated coke two-stage fluidized bed desulfurization device includes a return device, which includes a collecting hopper, a feeding bin and an N-type return valve. The powdered activated coke is transported to the feeding bin through an activated coke supply system. The bottom of the feeding bin is connected to the top of the collecting hopper through a pipeline provided with a metering device and a flow control device. The collecting hopper is connected to the return port of the dense phase section through a pipeline provided with an N-type return valve. The powdered activated coke two-stage fluidized bed desulfurization device comprises a feeding device, which is provided with a powdered activated coke supply port. After the amorphous powdered activated coke used for flue gas desulfurization is added into the feeding device through the powdered activated coke supply port, it is connected to the powdered activated coke feeding port of the powdered activated coke two-stage fluidized bed desulfurization device through a pipeline.

2. The device for dry desulfurization of flue gas with activated coke according to claim 1, characterized in that: A discharge port for desulfurized activated coke is provided at the lower part of the discharge collecting hopper of the discharge device, a return port for the dense phase section is provided on the side wall of the dense phase section, a feeding port for powdered activated coke is provided on the side wall of the dilute phase section, and a flue gas outlet for desulfurized activated coke is provided on the top of the dilute phase section.

3. The device for dry desulfurization of flue gas with activated coke according to claim 1, characterized in that: The diffusion angle θ formed by the diameter of the lower table of the truncated cone distribution plate of the flue gas air distribution device and the waistline of the truncated cone is 45~60°, the conveying flue gas inlet is arranged on the side wall of the central tube of the discharge device, and the fluidized flue gas inlet is arranged on the side wall of the air chamber of the flue gas air distribution device.

4. The device for dry desulfurization of flue gas with activated coke according to claim 1, characterized in that: A tapered section is arranged in the middle of a two-stage fluidized bed desulfurization device for powdered activated coke, and the tapered section connects a dense phase section and a dilute phase section. The ratio of the diameter of the lower dense phase section to the diameter of the upper dilute phase section is 1:(2-4), and the ratio of the height of the lower dense phase section to the height of the upper dilute phase section is 1:(0.5-2). The tapered section is truncated cone-shaped, including an upper table surface and a lower table surface. The diffusion angle α formed by the diameter of the lower table surface and the waistline of the truncated cone is 45-65°.

5. The device for flue gas activated coke dry desulfurization according to claim 1, characterized in that: The powdered activated coke two-stage fluidized bed desulfurization device also includes a primary cyclone separator, which is connected to the desulfurization flue gas outlet through a pipeline, the powdered activated coke collected by the primary cyclone separator enters the collecting hopper through the pipeline, and the flue gas at the top outlet of the primary cyclone separator enters the secondary cyclone separator; the powdered activated coke collected by the secondary cyclone separator is collected and recycled, and the flue gas at the top outlet of the secondary cyclone separator enters the bag dust collector; The bag filter is equipped with a flue gas discharge pipe after desulfurization and dust removal. The flue gas is discharged after passing through the pipe, and the powdered activated coke collected by the bag filter is recycled.

6. The device for dry desulfurization of flue gas with activated coke according to claim 1, characterized in that: A metering device and a star-shaped feeder are arranged on the feeding device pipeline to respectively record and control the flow of powdered activated coke.

7. A process for flue gas activated coke dry desulfurization, using the device according to any one of claims 1 to 6, characterized in that The following steps are involved: (1) Amorphous fine powdered activated coke is used as an adsorbent. The amorphous powdered activated coke is added to the activated coke feeding device through the activated coke supply system, and then enters the dilute phase section of the two-stage fluidized bed desulfurization device for powdered activated coke after being controlled and metered by the star feeder and metering device, and then falls into the dense phase section of the two-stage fluidized bed desulfurization device for powdered activated coke under the action of gravity; (2) After the undesulfurized flue gas enters the flue gas separation cylinder, it is divided into two gases and enters the dense phase section through the air chamber of the flue gas distribution device and the central tube respectively. Due to the airflow formed by the flue gas, the powdered activated coke as an adsorbent is fully mixed and turbulent with the flue gas, presenting a concentrated fluidization state, and the sulfur dioxide in the flue gas is fully absorbed by the activated coke; (3) After the activated coke particles rise to the dilute phase section together with the flue gas, due to the decrease in the flue gas velocity, a part of the particles return to the dense phase section due to their own gravity, and the other part of the activated coke is carried out of the powdered activated coke two-stage fluidized bed desulfurization device along with the flue gas; (4) The purified dust-containing flue gas passes through the first-stage cyclone separator, the second-stage cyclone separator and the bag dust collector and is discharged to the next process.

8. The process for flue gas activated coke dry desulfurization according to claim 7, characterized in that: The particle equivalent diameter of amorphous powdered activated coke is 0.5~1.0mm.

9. The process for flue gas activated coke dry desulfurization according to claim 7, characterized in that: The single set of flue gas activated coke dry desulfurization process is suitable for flue gas working conditions with flue gas flow rate of 40000-70000Nm 3 / h, the sulfur dioxide concentration in the inlet flue gas is ≤ 3000 mg / Nm 3 , dust concentration in flue gas ≤ 5 g / Nm 3 , the flue gas temperature is within the range of 120-160 ℃; the sulfur dioxide concentration in the treated flue gas is ≤ 35 mg / Nm 3 .

10. The process for flue gas activated coke dry desulfurization according to claim 7, characterized in that: The powdered activated coke collected by the first-stage cyclone separator and the powdered activated coke in part of the feed bin are controlled by the N-type return valve in the return device and enter the dense phase section of the two-stage fluidized bed desulfurization device for powdered activated coke to participate in desulfurization, thereby further improving the desulfurization adsorption performance of the powdered activated coke.

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