Desulfurization device in circulating fluidized bed boiler

Abstract

The utility model discloses an in-furnace desulfurization device of a circulating fluidized bed boiler. The in-furnace desulfurization device comprises filter assemblies arranged in pairs, a limestone furnace front bin and limestone feeding assemblies arranged in pairs. The limestone feeding assembly is communicated with the filtering assembly through a pipeline; a discharge port of the filter assembly is communicated with a feed port pipeline of the limestone furnace front bin; the other group of limestone feeding assembly is communicated with the filtering assembly through a pipeline; and a discharge port of the filter assembly is communicated with a feed port pipeline of the limestone furnace front bin. By means of the device, impurities in limestone powder can be filtered and removed in the conveying process, the operation failure rate of desulfurization system equipment in the boiler is reduced, and SO2 in flue gas at an outlet of the boiler is prevented from exceeding the standard.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of limestone conveying, in particular to a circulating fluidized bed boiler in-furnace desulfurization device. BACKGROUND

[0002] The flue gas generated by the circulating fluidized bed boiler contains a large amount of SO2, which needs to be treated in the furnace and outside the furnace to ensure that the flue gas meets the emission requirements. The in-furnace treatment is to reduce the SO2 content by spraying limestone powder into the boiler. Since the ammonia water concentration used by the off-furnace treatment system is set according to the SO2 content in the flue gas entering the off-furnace desulfurization system, when the SO2 content in the flue gas entering the off-furnace desulfurization system exceeds its treatment capacity, the off-furnace desulfurization system cannot effectively control the SO2 content in the flue gas, resulting in non-compliance of the flue gas emission. It is calculated that the SO2 content in the flue gas emitted by the existing circulating fluidized bed boiler can reach 5000-6000 mg / m 3 If not treated, it will seriously pollute the environment.

[0003] However, in the actual use process of the above-mentioned existing equipment, since the limestone powder in the feed cannot be completely removed in advance, a certain proportion of iron filings, wooden sticks, adhesive tape and other impurities exist in the limestone powder in the feed, which causes the variable frequency feeder to stop frequently due to the jamming of impurities during the limestone conveying and feeding process, and the boiler limestone feeding has to be stopped for impurity removal. At this time, there is no limestone powder sprayed into the furnace, and the in-furnace desulfurization cannot be carried out, which affects the treatment effect of the off-furnace desulfurization system, resulting in SO2 exceeding standard in the flue gas emitted by the boiler and not meeting the environmental protection requirements.

[0004] The existing limestone filtering device, such as the filter disclosed in CN201822271714.2, includes two filtering cylinders butted together, the filtering cylinder is a circular truncated cone without upper and lower bottom surfaces, and the two filtering cylinders are butted together at the end with larger diameter; a filter plate is arranged on at least one filtering cylinder at the butted end. The filter is of a jet shape, when the limestone powder is sprayed into the filtering cylinder under the action of compressed air, it rapidly spreads in the filtering cylinder, the fine powder is concentrated and enters the powder bin along the pipeline under the action of air pressure after passing through the filter plate, and the large particles are gathered on the filter plate after spreading and fall on the lower part of the perforated plate, the filtering effect is remarkable. However, when the air pressure is large, the impurities attached to the filter screen are easy to block the powder passing channel, affecting the effective filtration of the limestone powder and the normal feeding stability of the boiler.

[0005] The information disclosed in the background section is only intended to increase the understanding of the general background of the present application and should not be considered as admission or any form of suggestion that this information constitutes prior art. CONTENT OF THE PRESENT INVENTION

[0006] The application provides a circulating fluidized bed boiler in-furnace desulfurization device, which reduces the content of impurities in limestone powder entering the boiler through filtration, realizes stable operation of the boiler, and ensures that the flue gas emission meets the standard.

[0007] The application provides a circulating fluidized bed boiler in-furnace desulfurization device, which includes: a pair of filter assemblies, a limestone pre-furnace bin, and a pair of limestone feeding assemblies.

[0008] One group of limestone feeding assemblies and filter assemblies are in pipeline communication; the discharge port of the filter assembly is in pipeline communication with the feeding port of the limestone pre-furnace bin.

[0009] Another group of limestone feeding assemblies and filter assemblies are in pipeline communication; the discharge port of the filter assembly is in pipeline communication with the feeding port of the limestone pre-furnace bin.

[0010] The limestone feeding assembly includes: a limestone intermediate bin, a compressed air source, a bin pump, and a powder injector.

[0011] The discharge port of the limestone intermediate bin is in pipeline communication with the feeding port of the bin pump; the discharge port of the bin pump is in pipeline communication with the feeding port of the powder injector; and the gas outlet of the compressed air source is in pipeline communication with the gas inlet of the powder injector.

[0012] The gas outlet of the powder injector is in pipeline communication with the filter assembly.

[0013] Preferably, the filter assembly includes: a cylinder, a filter screen, a blow assisting port, a feeding interface, and a discharge interface.

[0014] The feeding interface and the discharge interface are symmetrically arranged on the opposite side walls of the cylinder.

[0015] The filter screen is arranged in the cylinder and divides the inner cavity of the cylinder into a feeding cavity and a discharge cavity.

[0016] The blow assisting port is arranged on the bottom surface of the cylinder and faces the feeding cavity.

[0017] The feeding interface is in pipeline communication with the discharge port of the feeding assembly; and the discharge interface is in pipeline communication with the feeding port of the pre-furnace bin.

[0018] Preferably, the filter assembly includes: a first branch pipe, a second branch pipe, a first valve, and a third valve.

[0019] The first branch pipe is in communication with the blow assisting port and the gas outlet of the compressed air source; and the first valve is arranged on the first branch pipe.

[0020] The second branch pipe is in communication with the discharge interface and the limestone pre-furnace bin; and the third valve is arranged on the second branch pipe.

[0021] Preferably, the filter assembly includes: a second valve; and the second valve is arranged on the pipeline in communication with the feeding interface and the gas outlet of the powder injector.

[0022] Preferably, the filtering assembly comprises: a cylinder cover, a connecting elbow, a plurality of mounting screw holes, a handle;

[0023] An opening is arranged on the top surface of the cylinder body, and the opening is covered by the cylinder cover;

[0024] The cylinder cover is hinged to the cylinder body through the connecting elbow;

[0025] A handle is arranged on the top surface of the cylinder cover;

[0026] The mounting screw holes are arranged through the cylinder cover and the cylinder body and are aligned on the cylinder cover and the cylinder body.

[0027] Preferably, the circulating fluidized bed boiler, the variable frequency feeder, the Roots blower, and the mixer are comprised; the discharge port of the limestone front bin is in pipeline communication with the feeding port of the variable frequency feeder; the discharge port of the variable frequency feeder is in pipeline communication with the feeding port of the mixer;

[0028] The Roots blower is in pipeline communication with the air inlet of the mixer;

[0029] The discharge port of the mixer is in pipeline communication with the powder inlet of the circulating fluidized bed boiler.

[0030] Preferably, the bin pump comprises: a branch pipe, a pump valve, a trapped orifice plate, and an exhaust pipe;

[0031] One end of the exhaust pipe is in communication with the top of the bin pump, and the other end is in communication with the limestone intermediate bin;

[0032] The trapped orifice plate and a plurality of pump valves are arranged on the branch pipe in intervals;

[0033] One end of the branch pipe is in communication with the air outlet of the compressed air source, and the other end is in communication with the upper part of the bin pump.

[0034] Preferably, the limestone intermediate bin comprises: a level meter and a dust collector; the dust collector is arranged on the top surface of the limestone intermediate bin; and the level meter is arranged on the side wall of the limestone intermediate bin.

[0035] Preferably, the limestone intermediate bin comprises: a breather valve; the breather valve is arranged on the top surface of the limestone intermediate bin.

[0036] The beneficial effects that can be produced by the present application include:

[0037] 1) The circulating fluidized bed boiler in-situ desulfurization device provided by the present application can filter and remove impurities in the limestone powder during the conveying process, reduce the equipment failure rate of the in-situ desulfurization system, and prevent the SO2 in the boiler outlet flue gas from exceeding the standard; after filtering with the device, the trapped impurities can be conveniently and quickly removed, avoiding shutdown for maintenance, effectively ensuring the continuous operation of the limestone conveying system, reducing the damage to the equipment, and increasing the service life of the equipment.

[0038] 2) The circulating fluidized bed boiler in-furnace desulfurization device provided by the application reduces the failure rate of the limestone variable frequency feeder from 15 times / month to 27 times / month to 2 times / month to 3 times / month, the failure rate is obviously reduced, the SO2 at the furnace outlet is effectively controlled, and the service life of each device in the limestone variable frequency feeder is prolonged. BRIEF DESCRIPTION OF DRAWINGS

[0039] Fig. 1 The circulating fluidized bed boiler in-furnace desulfurization device in at least one embodiment provided by the application is a schematic diagram;

[0040] Fig. 2 The filter front view structure schematic diagram in at least one embodiment provided by the application is a schematic diagram;

[0041] LEGEND:

[0042] Limestone intermediate bin 1, breather valve 11, level gauge 112, dust collector 114, exhaust pipe 115, feeding interface 13, compressed air source 3, bin pump 2, pump valve 21, interception orifice plate 22, powder injector 23, limestone furnace front bin 4, variable frequency feeder 41, Roots blower 42, mixer 43, circulating fluidized bed boiler 5, filter 31, cylinder body 311, cylinder cover 35, connecting elbow 312, connecting shaft 313, mounting screw hole 314, handle 315, feeding interface 331, discharging interface 332, filter screen 34, auxiliary blowing port 316, first branch pipe 323, second branch pipe 322, first valve 321, second valve 324, third valve 325. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0045] The technical means not described in detail in the present application and not used to solve the technical problems of the present application are set according to common knowledge in the art, and various common knowledge setting modes can be implemented.

[0046] Referring to Figs. 1-2 The circulating fluidized bed boiler furnace desulfurization device provided by the application comprises: a pair of limestone feeding assemblies, a pair of filtering assemblies, and a limestone forechamber 4; the limestone feeding assemblies and the filtering assemblies are taken as a group, the limestone feeding assemblies and the filtering assemblies are in pipeline communication, and the discharge port of the filtering assembly in the group is in pipeline communication with the feeding port of the limestone forechamber 4.

[0047] The limestone feeding assemblies and the filtering assemblies are taken as another group, the limestone feeding assemblies and the filtering assemblies are in pipeline communication, and the discharge port of the filtering assembly in the other group is in pipeline communication with the feeding port of the limestone forechamber 4; thus, when the group is stopped for cleaning, the limestone forechamber 4 can be normally fed.

[0048] In an embodiment, the limestone intermediate chamber 1 comprises: a breather valve 11, a level meter 112, a dust collector 114, an exhaust pipe 115, and a feeding interface 13.

[0049] The limestone intermediate chamber 1 is maintained at a positive pressure, and the breather valve 11, the dust collector 114, and the feeding interface 13 are arranged at intervals at the top of the limestone intermediate chamber 1; the feeding interface 13 is used for being connected to a discharge pipe of a tank truck for conveying limestone and for feeding; the dust collector 114 is used for discharging air in the limestone intermediate chamber 1 and forming a negative pressure area at the upper part of the limestone intermediate chamber 1 when limestone powder is fed, so as to facilitate feeding and to recycle dust in the discharged air in the limestone intermediate chamber 1, thereby avoiding environmental pollution.

[0050] The breather valve 11 is used for connecting the inside and outside of the limestone intermediate chamber 1, for example, when the dust collector 114 is maintained, the breather valve 11 can ensure safety in pressure. The air outlet of the filtering assembly is in pipeline communication with the feeding port of the limestone forechamber 4; the variable-frequency feeder 41 is arranged on the discharge port of the limestone forechamber 4 and is in pipeline communication with the discharge port; the feeding end of the mixer 43 is in pipeline communication with the discharge port of the variable-frequency feeder 41; the Roots blower 42 is in pipeline communication with the air inlet of the mixer 43; and the discharge port of the mixer 43 is in pipeline communication with the powder inlet of the circulating fluidized bed boiler 5. Thus, the variable-frequency feeder 41 can effectively remove impurities from the limestone powder entering the variable-frequency feeder 41, and the occurrence of a shutdown condition of the variable-frequency feeder 41 can be avoided.

[0051] In an embodiment, one end of the exhaust pipe 115 is connected to the limestone intermediate chamber 1, and the other end is connected to the chamber pump 2; through the pipeline, the gas in the chamber pump 2 can be discharged to the intermediate chamber.

[0052] In an embodiment, the lower part of the chamber pump 2 is connected to a powder injector, so as to accelerate the powder to be conveyed. The air inlet of the powder injector is in pipeline communication with the compressed air source 3, and the air outlet is in pipeline communication with the air inlet of the filtering assembly. A second valve 324 is arranged on the pipeline, and is used for controlling the feeding of the fluidized powder.

[0053] In a specific embodiment, the bin pump 2 comprises: a branch pipe; a plurality of pump valves 21 and trap orifice plates 22 arranged at intervals on the branch pipe; one end of the branch pipe is in communication with the top of the bin pump 2, and the other end is in communication with the outlet pipe of the compressed air source 3; compressed air enters the bin pump 2 through the branch pipe, fluidizes the powder in the bin pump 2, and facilitates transportation. The trap orifice plates 22 can maintain the pressure in the bin pump 2 stable, avoid the impact of excessive compressed air flow on the bin pump 2, and cooperate with the plurality of pump valves 21 to effectively control the fluidization of the powder in the bin pump 2.

[0054] The compressed air source 3 can be a compressed air generator or a compressed air storage tank, which is arranged in a common manner in the prior art and will not be described here.

[0055] The filter assembly comprises: a first filter assembly and a second filter assembly; so as to periodically clean the filter assembly as needed, maintain the stability of the limestone feed, and avoid the problem of no limestone feed during shutdown and cleaning. Rotating cleaning of each filter assembly at a frequency of 4h cleaning can ensure that the boiler flue gas meets the standard.

[0056] The first filter assembly and the second filter assembly are completely identical in structure and each comprises: a filter 31, a first branch pipe 323, a second branch pipe 322, a first valve 321, a second valve 324, and a third valve 325; the filter 31 comprises: a feed inlet, a discharge outlet, and a blow assisting port 316; the feed inlet of the filter 31 is in communication with the discharge outlet of the powder injector 23 of the bin pump 2 through a communication pipe, and the second valve 324 is arranged on the communication pipe; the discharge outlet of the filter 31 is in communication with the limestone furnace front bin 4 through the second branch pipe 322; the third valve 325 is arranged on the second branch pipe 322; the blow assisting port 316 of the filter 31 is in communication with the outlet of the compressed air source 3 through the first branch pipe 323, and the first valve 321 is arranged on the first branch pipe 323.

[0057] In a specific embodiment, the filter 31 comprises: a cylinder body 311, a cylinder cover 35, a connecting elbow 312, a connecting shaft 313, a feed interface 331, a discharge interface 332, and a filter screen 34; the feed interface 331 and the discharge interface 332 are symmetrically arranged on opposite sides of the cylinder body 311 as feed and discharge connection pipes; the top of the cylinder body 311 is open, and the cylinder cover 35 is arranged on the opening; the cylinder cover 35 and the cylinder body 311 are hinged through the connecting elbow 312 and the connecting shaft 313 arranged on one side of the cylinder body 311.

[0058] The filter screen 34 is arranged inside the filter 31 along the central symmetry axis of the cylinder body 311; the filter screen 34 divides the cylinder body 311 into a feed chamber and a discharge chamber; the feed interface 331 is arranged on the outer side wall of the feed chamber; the discharge interface 332 is arranged on the outer side wall of the discharge chamber. The blow assisting port 316 is arranged on the bottom surface of the cylinder body 311 opposite the feed chamber.

[0059] The fluidized limestone powder flowing into the filter 31 needs to pass through the filter screen 34 to be discharged. At this time, the impurities contained in the fluid are blocked by the filter screen 34, and the compressed air enters the cylinder 311 on the side of the filter screen 34 of the feed inlet through the blow assisting port 316, fluidizes the material passing through the filter screen 34, strengthens the dispersion uniformity of the powder in the gas, avoids the deposition of the powder material on the side of the filter screen 34 due to speed reduction, and ensures the normal and effective filtration of the powder.

[0060] In a specific embodiment, one end of the connecting elbow 312 is connected with the upper side wall of the cylinder 311, and the other end of the connecting elbow 312 is hingedly connected with one side of the cylinder cover 35, and the hinge shaft is the connecting shaft 313.

[0061] In a specific embodiment, mounting screw holes 314 are aligned and arranged on the cylinder 311 and the cylinder cover 35, so that the cylinder 311 can be closed by a bolt assembly and opened for regular maintenance.

[0062] In a specific embodiment, a handle 315 is arranged on the top surface of the cylinder cover 35, so as to facilitate opening operation.

[0063] In a specific embodiment, the aperture of the filter holes on the filter screen 34 is 12 mm, and the distance between any two filter holes on the filter screen 34 is 16 mm.

[0064] Embodiment:

[0065] The above technical innovation is carried out on the limestone conveying system of the boiler of the power station of Yunnan Yuntianhua Petrochemical Co., Ltd.

[0066] Before the reconstruction: The frequency of fault shutdown and cleaning of the limestone frequency feeders was 15 times / month to 27 times / month.

[0067] The safe operation period of the two circulating fluidized bed boilers was only 280 days, and the components needed to be replaced beyond the period;

[0068] Before the reconstruction, the outlet SO2 of the circulating fluidized bed boiler 5 fluctuated greatly, indicating that the desulfurization stability in the furnace was poor, which seriously affected the environmental protection index;

[0069] After the reconstruction: After the reconstruction in 2022, it has been continuously operated for 14370 hours, the fault rate of the limestone frequency feeder has been reduced from 15 times / month to 27 times / month to 2 times / month to 3 times / month, the fault rate has been obviously reduced, and the outlet SO2 of the hearth has also been effectively controlled.

[0070] Conclusion: Through the technical innovation reconstruction of the conveying system, not only the fault rate of the limestone frequency feeder is reduced, but also the reliability of the desulfurization system in the furnace is improved.

[0071] Although the utility model has been explained in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or make equivalent replacement to part of the technical features, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A circulating fluidized bed boiler furnace desulfurization device, characterized by, The invention relates to a limestone feeding system for a circulating fluidized bed boiler, which comprises: a pair of filter assemblies, a limestone forehearth (4), and a pair of limestone feeding assemblies; a group of limestone feeding assemblies and filter assemblies are in pipeline communication; the outlet of the filter assembly is in pipeline communication with the inlet of the limestone forehearth (4); another group of limestone feeding assemblies and filter assemblies are in pipeline communication; the outlet of the filter assembly is in pipeline communication with the inlet of the limestone forehearth (4); the limestone feeding assembly comprises a limestone intermediate bin (1), a compressed air source (3), a bin pump (2), and a powder injector (23); the outlet of the limestone intermediate bin (1) is in pipeline communication with the inlet of the bin pump (2); the outlet of the bin pump (2) is in pipeline communication with the inlet of the powder injector (23); the outlet of the compressed air source (3) is in pipeline communication with the inlet of the powder injector (23); the outlet of the powder injector (23) is in pipeline communication with the filter assembly.

2. The circulating fluidized bed boiler in-furnace desulfurization apparatus according to claim 1, characterized by, The filter assembly comprises a cylinder (311), a filter screen (34), a blow assisting port (316), an inlet interface (331), and an outlet interface (332); the inlet interface (331) and the outlet interface (332) are symmetrically arranged on the opposite side walls of the cylinder (311); the filter screen (34) is arranged in the cylinder (311) and divides the inner cavity of the cylinder (311) into an inlet cavity and an outlet cavity; the blow assisting port (316) is arranged on the bottom surface of the cylinder (311) and faces the inlet cavity; the inlet interface (331) is in pipeline communication with the outlet of the feeding assembly; the outlet interface (332) is in pipeline communication with the inlet of the limestone forehearth (4).

3. The circulating fluidized bed boiler in-furnace desulfurization apparatus according to claim 2, characterized by, The filter assembly comprises a first branch pipe (323), a second branch pipe (322), a first valve (321), and a third valve (325); the first branch pipe (323) is in communication with the blow assisting port (316) and the outlet of the compressed air source (3); the first valve (321) is arranged on the first branch pipe (323); the second branch pipe (322) is in communication with the outlet interface (332) and the limestone forehearth (4); the third valve (325) is arranged on the second branch pipe (322).

4. The circulating fluidized bed boiler in-furnace desulfurization apparatus according to claim 2, characterized by The filter assembly comprises a second valve (324); the second valve (324) is arranged on the pipeline which is in communication with the inlet interface (331) and the outlet of the powder injector (23).

5. The circulating fluidized bed boiler in-furnace desulfurization apparatus according to claim 2, characterized by The filter assembly comprises a cylinder cover (35), a connecting elbow (312), a plurality of mounting screw holes (314), and a handle (315); an opening is arranged on the top surface of the cylinder (311); the cylinder cover (35) is arranged on the opening; the cylinder cover (35) is hinged to the cylinder (311) through the connecting elbow (312); the handle (315) is arranged on the top surface of the cylinder cover (35); the mounting screw holes (314) are arranged on the cylinder cover (35) and the cylinder (311) in alignment.

6. The circulating fluidized bed boiler in-furnace desulfurization apparatus according to claim 1, characterized by The invention relates to a limestone feeding system for a circulating fluidized bed boiler, which comprises: a circulating fluidized bed boiler (5), a variable frequency feeder (41), a Roots blower (42), and a mixer (43); the outlet of the limestone forehearth (4) is in pipeline communication with the inlet of the variable frequency feeder (41); the outlet of the variable frequency feeder (41) is in pipeline communication with the inlet of the mixer (43); the Roots blower (42) is in pipeline communication with the inlet of the mixer (43). The discharge port of the mixer (43) is in communication with the powder inlet pipeline of the circulating fluidized bed boiler (5).

7. The circulating fluidized bed boiler in-furnace desulfurization apparatus according to claim 1, characterized by, The bin pump (2) comprises a branch pipe, a pump valve (21), a trapped orifice plate (22), and an exhaust pipe (115). One end of the exhaust pipe (115) is in communication with the top of the bin pump (2), and the other end is in communication with the limestone intermediate bin (1). The trapped orifice plate (22) and multiple pump valves (21) are arranged on the branch pipe at intervals. One end of the branch pipe is in communication with the air outlet of the compressed air source (3), and the other end is in communication with the upper part of the bin pump (2).

8. The circulating fluidized bed boiler in-furnace desulfurization apparatus according to claim 1, characterized by, The limestone intermediate bin (1) comprises a level gauge (112) and a dust remover (114).

9. The circulating fluidized bed boiler in-furnace desulfurization apparatus according to claim 1, characterized by, The dust remover (114) is arranged on the top surface of the limestone intermediate bin (1). The limestone intermediate bin (1) comprises a breather valve (11). The breather valve (11) is arranged on the top surface of the limestone intermediate bin (1).

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