Special yellow phosphorus tail gas incineration boiler capable of reducing oxygen content of flue gas

Abstract

The utility model relates to the technical field of boilers, in particular to a special yellow phosphorus tail gas burning boiler capable of reducing the oxygen content of flue gas, which comprises a yellow phosphorus tail gas storage tank, a desulfurization and dephosphorization agent storage bin and a hearth, a primary air chamber is mounted at the bottom end of the hearth, and an under-bed ignition and flue gas yellow phosphorus tail gas burner is mounted on the side wall of the primary air chamber. A yellow phosphorus tail gas storage tank is communicated with an under-bed ignition and flue gas yellow phosphorus tail gas burner through a pipeline, a desulfurization and dephosphorization agent conveyor is installed at the bottom end of a desulfurization and dephosphorization agent storage bin and communicated with the bottom end of a hearth through a pipeline, and two yellow phosphorus tail gas burners are fixedly installed on each of the two sides of the hearth. A secondary air box communicated with the interior of the hearth is further installed on the side wall of the hearth, a separator is fixedly installed on the outer side of the top end of the hearth, and a material returning device communicated with the bottom end of the hearth is installed at the bottom of the separator.

Description

Technical Field

[0001] This utility model relates to the field of boiler technology, and in particular to a special boiler for burning yellow phosphorus tail gas to reduce the oxygen content of flue gas. Background Technology

[0002] Yellow phosphorus tail gas, a byproduct generated during the production of yellow phosphorus, has a complex composition and contains various highly toxic substances, posing a serious threat to the environment and human health. Yellow phosphorus tail gas is classified into two types: purified and primary purified. Due to the high cost of purification, many companies only perform primary purification. Primary purified yellow phosphorus tail gas contains a large amount of phosphorus and impurities, causing severe blockage and corrosion to equipment utilizing it. Since phosphorus combustion produces P2O5, which combines with water to form H3PO4, and H3PO4 is highly corrosive, the lifespan of metals used in boilers with this yellow phosphorus tail gas as fuel is very short, generally not exceeding three months, severely impacting its utilization. Therefore, many companies directly ignite and discharge it via flares, causing severe air pollution and energy waste. This application proposes a dedicated boiler for incinerating yellow phosphorus tail gas with reduced oxygen content in the flue gas. Utility Model Content

[0003] To address the shortcomings of existing technologies, the purpose of this utility model is to provide a special boiler for burning yellow phosphorus tail gas with reduced oxygen content in flue gas. This solves the problems mentioned above, such as severe corrosion of equipment by phosphorus in yellow phosphorus tail gas during use, and low utilization rate of common yellow phosphorus tail gas ignition methods, resulting in energy waste and environmental pollution.

[0004] To achieve the above objectives, this utility model is implemented through the following technical solution: It includes a yellow phosphorus tail gas storage tank, a desulfurization and dephosphorization agent storage silo, and a furnace. A primary air chamber is installed at the bottom of the furnace. An under-bed ignition and flue gas yellow phosphorus tail gas burner is installed on the side wall of the primary air chamber. The yellow phosphorus tail gas storage tank is connected to the under-bed ignition and flue gas yellow phosphorus tail gas burner via a pipeline. A desulfurization and dephosphorization agent conveyor is installed at the bottom of the desulfurization and dephosphorization agent storage silo. The desulfurization and dephosphorization agent conveyor is connected to the bottom of the furnace via a pipeline. Two yellow phosphorus tail gas burners are fixedly installed on both sides of the furnace. A secondary air box connected to the furnace interior is also installed on the side wall of the furnace. A separator is fixedly installed on the outer side of the top of the furnace. A return feeder connected to the bottom of the furnace is installed at the bottom of the separator. A flue gas treatment chamber connected to the separator is installed at the top of the separator.

[0005] Optionally, a dust collector is connected to the bottom of the flue gas treatment chamber via a pipe, and a desulfurization tower is connected to one side of the dust collector via a pipe. The desulfurization tower is connected to a chimney via a pipe, and an induced draft fan is installed on the pipe between the dust collector and the desulfurization tower.

[0006] Optionally, a flue gas recirculation fan is connected to the outlet of the induced draft fan via a pipe. A branch pipe is connected to the flue gas recirculation fan. One end of the branch pipe is connected to the secondary air box, and the other end of the branch pipe is connected to the primary air fan. The outlet of the primary air fan is connected to the under-bed ignition and flue gas yellow phosphorus tail gas burner via a pipe.

[0007] Optionally, a secondary air box is connected to a secondary air fan via a pipeline, and a yellow phosphorus tail gas conveying fan is installed between the yellow phosphorus tail gas storage tank and the pipeline of the under-bed ignition and flue gas yellow phosphorus tail gas burner.

[0008] Optionally, the flue gas treatment chamber is equipped with a superheater, an economizer, and an SCR denitrification agent from top to bottom. There are two sets of economizers, which are placed above and below the SCR denitrification agent, respectively.

[0009] Optionally, multiple SNCR nozzles that communicate with the interior are fixedly installed on the side wall of the furnace.

[0010] Optionally, the flue gas treatment chamber includes a pipe body, a sealing cover, and a sealing plate. An access port is provided on the side wall of the pipe body. A reversible sealing cover is hinged between the access ports. The sealing plate is fixedly installed at the edge of the outer wall of the sealing cover, with its inner wall fitting against the outer wall of the pipe body. A fixing ring, flush with the bottom of the access port, is fixedly installed inside the pipe body. A placement seat is provided on the fixing ring, and a through-hole is provided on the placement seat. A cross-shaped support frame is fixedly installed at the bottom of the through-hole. The SCR denitrification agent is in honeycomb block form and placed inside the through-hole on the placement seat. The end of the sealing plate away from the hinge is connected to the outer wall of the pipe body by bolts.

[0011] The beneficial effects of this utility model are:

[0012] 1. Dephosphorizing and desulfurizing agents (limestone, phosphate rock powder, coal gangue, slag, etc.) contain a large amount of CaO. CaO reacts with P2O5 to generate Ca3(PO4)2, and the decomposition temperature of Ca3(PO4)2 is above 1350℃, which can effectively prevent phosphorus from corroding the metal heating surface.

[0013] 2. By installing a flue gas recirculation fan at the outlet of the induced draft fan, a portion of the flue gas enters the inlet of the primary fan, and a portion of the flue gas enters the secondary air box, thereby reducing the oxygen content in the emitted flue gas.

[0014] 3. The use of a circulating fluidized bed boiler increases the concentration of dephosphorizing agent in the furnace, thereby improving the efficiency of dephosphorizing and desulfurizing agent use.

[0015] 4. By closing the flow of the pipeline between the separator and the flue gas treatment chamber, then opening the sealing cover on the pipe body to remove the storage seat, and replacing the SCR denitrification agent on the storage seat, the storage seat containing the SCR denitrification agent can be quickly replaced by placing it back onto the fixing ring in the pipe body through the removal port. This allows the SCR denitrification agent to continue to play its role in the treatment of flue gas. Attached Figure Description

[0016] Other features, objects, and advantages of this invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0017] Figure 1 This is a schematic diagram of the overall process structure of this utility model;

[0018] Figure 2 This is a schematic diagram of the closed sealing cap structure of the tube body of this utility model;

[0019] Figure 3 This is a schematic diagram of the structure of the sealing cap on the tube body of this utility model when it is open;

[0020] Figure 4 This is a schematic diagram of the structure of the tube body and the storage seat of this utility model;

[0021] In the diagram: 1. Yellow phosphorus tail gas storage tank; 2. Yellow phosphorus tail gas conveying fan; 3. Desulfurization and dephosphorization agent storage silo; 4. Secondary air box; 5. Desulfurization and dephosphorization agent conveyor; 6. Yellow phosphorus tail gas burner; 7. Primary air chamber; 8. Under-bed ignition and flue gas yellow phosphorus tail gas burner; 9. Furnace; 10. Separator; 11. Return feeder; 12. Superheater; 13. Economizer; 14. SNCR nozzle; 15. SCR denitrification agent; 16. Primary air fan; 17. Secondary air fan; 18. Flue gas recirculation fan; 19. Exhaust fan; 20. Dust collector; 21. Chimney; 22. Desulfurization tower; 231. Pipe body; 232. Sealing cover; 233. Sealing plate; 234. Storage seat; 235. Fixing ring. Detailed Implementation

[0022] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0023] Please see Figures 1-4This utility model provides a technical solution: it includes a yellow phosphorus tail gas storage tank 1, a desulfurization and dephosphorization agent storage silo 3, and a furnace 9. A primary air chamber 7 is installed at the bottom of the furnace 9. An under-bed ignition and flue gas yellow phosphorus tail gas burner 8 is installed on the side wall of the primary air chamber 7. The under-bed ignition and flue gas yellow phosphorus tail gas burner 8 can increase the temperature of the lower part of the furnace 9, thereby accelerating the desulfurization and dephosphorization reaction rate. The yellow phosphorus tail gas storage tank 1 is connected to the under-bed ignition and flue gas yellow phosphorus tail gas burner 8 through a pipeline. A desulfurization and dephosphorization agent conveyor 5 is installed at the bottom of the phosphorus agent storage silo 3. The desulfurization and dephosphorization agent conveyor 5 is connected to the bottom of the furnace 9 through a pipeline. Two yellow phosphorus tail gas burners 6 are fixedly installed on both sides of the furnace 9. A secondary air box 4 connected to the inside of the furnace 9 is also installed on the side wall of the furnace 9. A separator 10 is fixedly installed on the outer side of the top of the furnace 9. A return feeder 11 connected to the bottom of the furnace 9 is installed at the bottom of the separator 10. A flue gas treatment chamber connected to the separator 10 is installed at the top of the separator 10.

[0024] The desulfurization and dephosphorization agents (limestone, phosphate rock powder, coal gangue, slag, etc.) in the desulfurization and dephosphorization agent storage silo 3 are transported to the furnace 9 by the desulfurization and dephosphorization agent conveyor 5 arranged below it to participate in combustion. During the combustion process, the desulfurization and dephosphorization agents can effectively prevent the boiler from being corroded when burning yellow phosphorus tail gas. The desulfurization and dephosphorization agents contain a large amount of CaO and are suspended in the middle of the furnace 9. The CaO in the desulfurization and dephosphorization agents reacts with P2O5 to generate Ca3(PO4)2, and the decomposition temperature of Ca3(PO4)2 is above 1350℃, which can effectively prevent phosphorus from corroding the metal heating surface.

[0025] In order to improve the utilization efficiency of desulfurization and dephosphorization agents, the desulfurization and dephosphorization agents carried in the flue gas are separated by separator 10, and the desulfurization and dephosphorization agents separated by separator 10 are sent into furnace 9 through return feeder 11, thereby increasing the concentration of desulfurization and dephosphorization agents in furnace 9 and thus improving the phosphorus removal rate.

[0026] like Figure 1 As shown, a dust collector 20 is connected to the bottom of the flue gas treatment chamber via a pipe. A desulfurization tower 22 is connected to one side of the dust collector 20 via a pipe. The desulfurization tower 22 is connected to a chimney 21 via a pipe. An induced draft fan 19 is installed on the pipe between the dust collector 20 and the desulfurization tower 22. The flue gas in the dust collector 20 enters the desulfurization tower 22 via the induced draft fan 19, and then enters the chimney 21 via the pipe and is discharged into the atmosphere.

[0027] like Figure 1 As shown, the exhaust port of the induced draft fan 19 is connected to the flue gas recirculation fan 18 via a pipe. The flue gas recirculation fan 18 is connected to a branch pipe. One end of the branch pipe is connected to the secondary air box 4, and the other end of the branch pipe is connected to the primary air fan 16. The exhaust port of the primary air fan 16 is connected to the under-bed ignition and flue gas yellow phosphorus tail gas burner 8 via a pipe.

[0028] To reduce the O2 content in the flue gas, a portion of the flue gas is drawn from the outlet of the induced draft fan 19 by the flue gas recirculation fan 18 and then into the primary fan 16 and the secondary air box 4, thereby reducing the oxygen content in the flue gas and meeting the requirements for environmental protection emissions.

[0029] To reduce NOx emissions, a recirculation inlet is installed on the inlet side of the secondary air box 4. The recirculated flue gas is taken from the outlet of the induced draft fan 19 and is pressurized by the flue gas recirculation fan 18 and transported to the inlet side of the yellow phosphorus tail gas burner 6. During the combustion of the yellow phosphorus tail gas, it plays a role in cooling. At the same time, the yellow phosphorus tail gas burns in a reducing atmosphere, which reduces the NOx emissions in the flue gas.

[0030] like Figure 1 As shown, the secondary air box 4 is connected to the secondary air fan 17 via a pipeline. A yellow phosphorus tail gas conveying fan 2 is installed between the yellow phosphorus tail gas storage tank 1 and the pipeline of the under-bed ignition and flue gas yellow phosphorus tail gas burner 8. The yellow phosphorus tail gas in the yellow phosphorus tail gas storage tank 1 can be conveyed to the under-bed ignition and flue gas yellow phosphorus tail gas burner 8 by the yellow phosphorus tail gas conveying fan 2. The secondary air fan 17 and the primary air fan 16 can provide air for the combustion of yellow phosphorus tail gas.

[0031] like Figure 1 As shown, the flue gas treatment chamber is equipped with a superheater 12, an economizer 13, and an SCR denitrification agent 15 from top to bottom. The economizer 13 has two sets, which are placed above and below the SCR denitrification agent 15, respectively. The superheater 12 heats the saturated steam into superheated steam to improve the thermal efficiency and work capacity of the steam. The economizer 13 has the function of waste heat recovery and temperature regulation. It uses the waste heat of the flue gas to heat the boiler feedwater, improve the boiler thermal efficiency, and reduce the temperature of the flue gas entering the SCR denitrification agent 15. The SCR denitrification agent 15 includes a reducing agent (such as ammonia or urea) and a catalyst. The reducing agent reacts with NOx in the flue gas to produce harmless nitrogen and water. The catalyst acts as a reaction medium to reduce the activation energy of the reaction, so that the reduction reaction can be carried out efficiently at a lower temperature (usually 260-400℃).

[0032] like Figure 1 As shown, multiple SNCR nozzles 14 connected to the interior are fixedly installed on the side wall of the furnace 9. The core function of the SNCR nozzles 14 is to maximize the denitrification efficiency under catalyst-free conditions through precise temperature control, efficient mixing and reasonable layout, while taking into account equipment safety and economy.

[0033] like Figures 2-4As shown, the flue gas treatment chamber includes a pipe body 231, a sealing cover 232, and a sealing plate 233. An access port is provided on the side wall of the pipe body 231. A reversible sealing cover 232 is hinged between the access ports. The sealing plate 233 is fixedly installed at the edge of the outer wall of the sealing cover 232, and the inner wall of the sealing plate 233 is flush with the outer wall of the pipe body 231. A fixing ring 235, flush with the bottom of the access port, is fixedly installed inside the pipe body 231. A storage seat 234 is provided on the fixing ring 235, and a through-hole is provided on the storage seat 234. The opening has a cross-shaped support frame fixedly installed at the bottom. The SCR denitrification agent 15 is in the shape of a honeycomb block and is placed in the opening on the storage seat 234. The end of the sealing plate 233 away from the hinge is connected to the outer wall of the pipe body 231 by bolts. By unscrewing the bolts and flipping the sealing cover 232, the access port on the pipe body 231 can be opened. Then, the storage seat 234 can be taken out, the SCR denitrification agent 15 inside can be replaced, and then put back into the pipe body 231. The operation is simple and convenient, and the replacement of SCR denitrification agent 15 in the flue gas treatment chamber can be completed quickly.

[0034] Although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A special boiler for burning yellow phosphorus tail gas with reduced oxygen content in flue gas, comprising a yellow phosphorus tail gas storage tank (1), a desulfurization and dephosphorization agent storage bin (3), and a furnace (9), characterized in that, A primary air chamber (7) is installed at the bottom of the furnace (9). An under-bed ignition and flue gas yellow phosphorus tail gas burner (8) is installed on the side wall of the primary air chamber (7). A yellow phosphorus tail gas storage tank (1) is connected to the under-bed ignition and flue gas yellow phosphorus tail gas burner (8) through a pipe. A desulfurization and dephosphorization agent conveyor (5) is installed at the bottom of the desulfurization and dephosphorization agent storage silo (3). The desulfurization and dephosphorization agent conveyor (5) is connected to the bottom of the furnace (9) through a pipe. Two yellow phosphorus tail gas burners (6) are fixedly installed on both sides of the furnace (9). A secondary air box (4) connected to the inside of the furnace (9) is also installed on the side wall of the furnace (9). A separator (10) is fixedly installed on the outer side of the top of the furnace (9). A return feeder (11) connected to the bottom of the furnace (9) is installed at the bottom of the separator (10). A flue gas treatment chamber connected to the separator (10) is installed at the top of the separator (10).

2. The special boiler for yellow phosphorus tail gas combustion with reduced oxygen content in flue gas according to claim 1, characterized in that, The bottom of the flue gas treatment chamber is connected to a dust collector (20) via a pipe. A desulfurization tower (22) is connected to one side of the dust collector (20) via a pipe. The desulfurization tower (22) is connected to a chimney (21) via a pipe. An induced draft fan (19) is installed on the pipe between the dust collector (20) and the desulfurization tower (22).

3. A special boiler for burning yellow phosphorus tail gas with reduced oxygen content in flue gas according to claim 2, characterized in that, The exhaust port of the induced draft fan (19) is connected to a flue gas recirculation fan (18) via a pipe. A branch pipe is connected to the flue gas recirculation fan (18). One end of the branch pipe is connected to the secondary air box (4), and the other end of the branch pipe is connected to a primary air fan (16). The exhaust port of the primary air fan (16) is connected to the under-bed ignition and flue gas yellow phosphorus tail gas burner (8) via a pipe.

4. A special boiler for burning yellow phosphorus tail gas with reduced oxygen content in flue gas according to claim 1, characterized in that, The secondary air box (4) is connected to a secondary air fan (17) via a pipeline, and a yellow phosphorus tail gas conveying fan (2) is installed between the yellow phosphorus tail gas storage tank (1) and the pipeline of the under-bed ignition and flue gas yellow phosphorus tail gas burner (8).

5. A special boiler for burning yellow phosphorus tail gas with reduced oxygen content in flue gas according to claim 1, characterized in that, The flue gas treatment chamber is provided with a superheater (12), an economizer (13) and an SCR denitrification agent (15) from top to bottom. The economizer (13) is provided in two sets and is placed above and below the SCR denitrification agent (15) respectively.

6. A special boiler for burning yellow phosphorus tail gas with reduced oxygen content in flue gas according to claim 1, characterized in that, The side wall of the furnace (9) is fixedly installed with multiple SNCR nozzles (14) that communicate with its interior.

7. A special boiler for burning yellow phosphorus tail gas with reduced oxygen content in flue gas according to claim 5, characterized in that, The flue gas treatment chamber includes a pipe body (231), a sealing cover (232), and a sealing plate (233). An access port is provided on the side wall of the pipe body (231). The access ports are hinged together by a reversible sealing cover (232). The sealing plate (233) is fixedly installed at the edge of the outer wall of the sealing cover (232), and the inner wall of the sealing plate (233) is flush with the outer wall of the pipe body (231). A [missing information - likely a device or component] is fixedly installed inside the pipe body (231). A fixing ring (235) flush with the bottom of the retrieval port is provided with a storage seat (234). The storage seat (234) has a through-hole. A cross-shaped support frame is fixedly installed at the bottom of the through-hole. The SCR denitrification agent (15) is in the shape of a honeycomb block and is placed in the through-hole on the storage seat (234). The end of the sealing plate (233) away from the hinge is connected to the outer wall of the pipe body (231) by bolts.

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