Epitaxial circulating fluidized bed semi-dry desulfurization and dust removal system and desulfurization and dust removal method

Abstract

The invention discloses an epitaxial circulating fluidized bed semi-dry desulfurization and dust removal system and a desulfurization and dust removal method. The system comprises: a desulfurization tower, which comprises a vertical section and an epitaxial section, one end of the epitaxial section is connected to the top of the vertical section, and the other end of the epitaxial section is inclined downward; a fluidizing air chamber is arranged at the bottom of the epitaxial section, and a fluidizing plate is arranged at the top of the fluidizing air chamber; a dust collector, whose inlet is connected to the end of the epitaxial section, whose gas outlet is connected to the fluidizing air chamber, and whose solid outlet is connected to the bottom of the vertical section of the desulfurization tower through a chute. By adopting the epitaxial scheme of the desulfurization tower, the flue gas and the desulfurizer powder can continue to react in the epitaxial section of the desulfurization tower, which can effectively reduce the height of the desulfurization tower and reduce the system investment.

Description

Technical Field

[0001] The invention relates to the field of flue gas treatment, and in particular to an epitaxial circulating fluidized bed semi-dry desulfurization and dust removal system and a desulfurization and dust removal method. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] The semi-dry desulfurization and dust removal technology of circulating fluidized bed can synergistically remove pollutants such as acid gases, mercury, HCl, HF, dust, etc. in flue gas, and no desulfurization wastewater is generated; the flue gas temperature is always above the acid dew point, so the equipment and flue do not need corrosion protection. At present, this technology is widely used in the environmental protection supporting of circulating fluidized bed boiler units. The flue gas desulfurization process is mainly completed in the desulfurization tower. In order to achieve SO2≤35mg / Nm 3 The ultra-low emission requirements usually require that the flue gas stay in the desulfurization tower for ≥ 6s. The inventors found that under this requirement, the height of the desulfurization tower is usually high, and the top elevation of the entire system is also high, even higher than the top elevation of the boiler. On the one hand, the cost of the desulfurization tower body and its affiliated civil engineering and steel beam structures is high. On the other hand, the installation process of the desulfurization tower is complicated and the lifting is difficult. Summary of the invention

[0004] In order to solve the technical problems existing in the prior art, the purpose of the present invention is to provide an epitaxial circulating fluidized bed semi-dry desulfurization and dust removal system and a desulfurization and dust removal method. By introducing an epitaxial desulfurization tower scheme to reduce the height of the desulfurization tower, while effectively utilizing the electric bag dust collector, the system investment is effectively reduced.

[0005] To solve the above technical problems, one or more embodiments of the present invention provide the following technical solutions:

[0006] In a first aspect, the present invention aims to provide an epitaxial circulating fluidized bed semi-dry desulfurization and dust removal system, comprising:

[0007] The desulfurization tower comprises a vertical section and an extension section, one end of the extension section is connected to the top of the vertical section, and the other end of the extension section is inclined downward;

[0008] A fluidizing air chamber is provided at the bottom of the extension section, and a fluidizing plate is provided at the top of the fluidizing air chamber;

[0009] The dust collector has an inlet connected to the end of the extension section, a gas outlet connected to the fluidizing wind chamber, and a solid outlet connected to the bottom of the vertical section of the desulfurization tower through a chute.

[0010] In a second aspect, the present invention aims to provide an epitaxial circulating fluidized bed semi-dry desulfurization and dust removal method, comprising the following steps:

[0011] The flue gas enters the desulfurization tower and is mixed with the desulfurizer sprayed in the vertical section of the desulfurization tower for desulfurization;

[0012] The mixture of partially desulfurized flue gas and desulfurizer powder flows out from the top of the vertical section of the desulfurization tower and enters the extended section of the desulfurization tower to continue desulfurization;

[0013] After the flue gas that meets the desulfurization standards enters the dust collector for dust removal, part of the flue gas flows back to the fluidized air chamber at the bottom of the extended section of the desulfurization tower, and fluidized air is blown into the extended section of the desulfurization tower to blow up the desulfurizer powder settled in the extended section.

[0014] Compared with the prior art, the above one or more technical solutions of the present invention have achieved the following beneficial effects:

[0015] (1) By adopting the desulfurization tower extension scheme, the flue gas and the desulfurizer powder can continue to react in the extension section of the desulfurization tower, which can effectively reduce the height of the desulfurization tower, reduce system investment, and reduce the difficulty of desulfurization tower installation;

[0016] (2) The clean flue gas purified by the bag filter is introduced back to the extension section of the desulfurization tower in the form of fluidized air, which can effectively prevent the desulfurizer from settling in the extension section;

[0017] (3) The overflow plate can collect part of the settled desulfurizer directly into the ash hopper of the dust collector by overflow, which reduces the dust concentration in the flue gas entering the bag filter, helps to increase the filtration wind speed of the bag and reduce the number of bags;

[0018] (4) At present, there are few newly built thermal power units, and most of them are to optimize the environmental protection facilities of existing units to make their pollutant emission standards meet the ultra-low emission requirements. For existing circulating fluidized bed units, electric bag dust collectors are usually installed to control dust emissions. Therefore, in order to effectively reduce the cost of installing and modifying desulfurization and dust removal equipment in a limited space, the present invention adopts a solution to reduce the height of the desulfurization tower, and the existing electric bag dust collector can be reused to reduce the total cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0020] Figure 1 It is a schematic diagram of the overall structure of the epitaxial circulating fluidized bed desulfurization and dust removal system in Example 1 of the present invention;

[0021] Figure 2It is a schematic diagram of the external structure of the epitaxial circulating fluidized bed desulfurization and dust removal system in Example 1 of the present invention;

[0022] Among them, 1. desulfurization tower system, 101. return section, 102. acceleration section, 103. gradual expansion section, 104. straight section;

[0023] 2. Desulfurization tower epitaxial system, 201, epitaxial section, 202, fluidizing plate, 203, fluidizing air chamber;

[0024] 3. Bag filter system, 301. Bag cleaning system, 302. Dust collector inlet, 303. Bag, 304. Bag chamber, 305. Ash hopper, 306. Dust collector outlet flue;

[0025] 4. Return system, 401, return valve, 402, fluidizing chute;

[0026] 5. epitaxial fluidization system, 501. pipeline, 502. heater, 503. booster fan;

[0027] 6. Desulfurizer overflow system, 601, overflow plate, 602, overflow pipe;

[0028] 7. The first electric field, 8. The second electric field, 9. The first bag dust collector, 10. The second bag dust collector. DETAILED DESCRIPTION

[0029] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0030] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0031] In a first aspect, the present invention aims to provide an epitaxial circulating fluidized bed semi-dry desulfurization and dust removal system, comprising:

[0032] The desulfurization tower comprises a vertical section and an extension section, one end of the extension section is connected to the top of the vertical section, and the other end of the extension section is inclined downward;

[0033] A fluidizing air chamber is provided at the bottom of the extension section, and a fluidizing plate is provided at the top of the fluidizing air chamber;

[0034] The dust collector has an inlet connected to the end of the extension section, a gas outlet connected to the fluidizing wind chamber, and a solid outlet connected to the bottom of the vertical section of the desulfurization tower through a chute.

[0035] In some embodiments, the ratio of the axial lengths of the vertical section and the extended section of the desulfurization tower is 1-3:1.

[0036] In some embodiments, the angle between the extended section and the vertical section of the desulfurization tower is ≤8°.

[0037] In some embodiments, the bottom of the end of the extension section is connected to the ash hopper of the dust collector through a pipeline.

[0038] The bottom of the end of the extension section is connected to the ash hopper of the dust collector through a pipeline, so that the desulfurizer powder settled at the bottom of the extension section can be recovered into the dust collector to reduce the dust concentration of the flue gas entering the dust collector.

[0039] Furthermore, a baffle is provided at the end of the extension section, and the baffle extends upward from the bottom of the extension section.

[0040] Furthermore, types of fluidizing plates include but are not limited to perforated plates, wind caps, fluidizing canvases, and metal sintered plates.

[0041] In some embodiments, a booster fan and a heater are provided on the connecting pipe between the dust collector and the fluidizing air chamber.

[0042] By using a booster fan to boost the flue gas entering the fluidizing air chamber, the fluidization effect of this part of the flue gas on the settling desulfurizer can be improved. At the same time, this part of the flue gas is heated to prevent the fluidizing flue gas temperature from being too low, which will have an adverse effect on the desulfurization effect of the flue gas.

[0043] In some embodiments, the dust collector is a bag dust collector, and the bag dust collector adopts a high-pressure blowing form.

[0044] In a second aspect, the present invention aims to provide an epitaxial circulating fluidized bed semi-dry desulfurization and dust removal method, comprising the following steps:

[0045] The flue gas enters the desulfurization tower and is mixed with the desulfurizer sprayed in the vertical section of the desulfurization tower for desulfurization;

[0046] The mixture of partially desulfurized flue gas and desulfurizer powder flows out from the top of the vertical section of the desulfurization tower and enters the extended section of the desulfurization tower to continue desulfurization;

[0047] After the flue gas that meets the desulfurization standards enters the dust collector for dust removal, part of the flue gas flows back to the fluidized air chamber at the bottom of the extended section of the desulfurization tower, and fluidized air is blown into the extended section of the desulfurization tower to blow up the desulfurizer powder settled in the extended section.

[0048] In some embodiments, the cross-sectional flow velocity of the flue gas in the extended section of the desulfurization tower is 8-12 m / s.

[0049] In some embodiments, the wind pressure in the fluidizing air chamber is 90-110 kPa.

[0050] Furthermore, the air temperature in the fluidizing air chamber is 100-120°C.

[0051] Example 1

[0052] An epitaxial circulating fluidized bed semi-dry desulfurization and dust removal system is provided with a desulfurization tower system 1, a desulfurization tower epitaxial system 2, a bag filter system 3, a return system 4, and an epitaxial fluidization system 5; the desulfurization tower system 1 is composed of a return section 101, an acceleration section 102, a gradual expansion section 103, and a straight section 104; the desulfurization tower epitaxial system 2 It is composed of an extension section 201, a fluidizing plate 202, and a fluidizing air chamber 203; the bag dust collector system 3 is composed of a bag cleaning system 301, a dust collector inlet 302, bags 303, a bag bin 304, an ash hopper 305, and a dust collector outlet flue 306; the return system 4 is composed of a return valve 401 and a fluidizing chute 402; the extension fluidization system 5 is composed of a pipeline 501, a heater 502, and a booster fan 503; the desulfurizer overflow system 6 is composed of an overflow plate 601 and an overflow pipe 602; the dust collector outlet flue 306 is connected to the booster fan 502, and the booster fan 502 is connected to the fluidizing air chamber 203.

[0053] The inclination angle of the desulfurization tower epitaxial system 2 is 12°; the flow velocity of the epitaxial section 201 is 10m / s; the fluidizing plate 202 adopts a wind cap, and the flow velocity of the wind hole is 20m / s; the wind pressure of the fluidizing air chamber 203 is 101kPa; the wind temperature of the fluidizing air chamber 203 is 110℃; the dust concentration of the flue gas in the dust collector outlet flue 306 is 5mg / Nm 3 The heater 502 adopts steam heating to increase and heat the clean flue gas at the bag filter outlet to 110°C through the booster fan 502 and enter the fluidizing chamber 203; the height of the overflow plate 601 is 1 / 5 of the height of the cross section of the extension section 201; the bag filter system adopts a new construction method.

[0054] Example 2

[0055] An epitaxial circulating fluidized bed semi-dry desulfurization and dust removal system is provided with a desulfurization tower system 1, a desulfurization tower epitaxial system 2, a bag filter system 3, a return system 4, and an epitaxial fluidization system 5; the desulfurization tower system 1 is composed of a return section 101, an acceleration section 102, a gradual expansion section 103, and a straight section 104; the desulfurization tower epitaxial system 2 It is composed of an extension section 201, a fluidizing plate 202, and a fluidizing air chamber 203; the bag dust collector system 3 is composed of a bag cleaning system 301, a dust collector inlet 302, bags 303, a bag bin 304, an ash hopper 305, and a dust collector outlet flue 306; the return system 4 is composed of a return valve 401 and a fluidizing chute 402; the extension fluidization system 5 is composed of a pipeline 501, a heater 502, and a booster fan 503; the desulfurizer overflow system 6 is composed of an overflow plate 601 and an overflow pipe 602; the dust collector outlet flue 306 is connected to the booster fan 502, and the booster fan 502 is connected to the fluidizing air chamber 203.

[0056] The inclination angle of the desulfurization tower epitaxial system 2 is 8°; the flow velocity of the epitaxial section 201 is 10m / s; the fluidized plate 202 adopts a metal sintered plate; the flow velocity of the fluidized plate 202 is ≥3m 3 / (m 2 ·s); the wind pressure of the fluidizing air chamber 203 is 101 kPa; the wind temperature of the fluidizing air chamber 203 is 110°C; the dust concentration of the flue gas in the dust collector outlet flue 306 is 2 mg / Nm 3 The heater 502 adopts steam heating to pressurize and heat the clean flue gas at the bag filter outlet to 110°C through the booster fan 502 and enter the fluidizing chamber 203; the height of the overflow plate 601 is 1 / 4 of the cross-sectional height of the extension section 201.

[0057] The original system adopts the electric bag dust collector scheme, which is equipped with two electric fields, the first electric field 7 and the second electric field 8, and two bag dust collectors, the first bag dust collector 9 and the second bag dust collector 10. Figure 2 As shown. The bag filter system adopts the method of reusing the old one, and the first electric field 7 of the two electric fields is retained as a flue gas pre-dust collector to remove most of the fly ash in the flue gas; the second electric field 8 is removed as the entrance of the modified bag filter, the first bag filter 9 and the second bag filter 10 are reused, and the original bag filter outlet flue remains unchanged.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An epitaxial circulating fluidized bed semi-dry desulfurization and dust removal system, characterized in that: include: The desulfurization tower comprises a vertical section and an extension section, one end of the extension section is connected to the top of the vertical section, and the other end of the extension section is inclined downward; A fluidizing air chamber is provided at the bottom of the extension section, and a fluidizing plate is provided at the top of the fluidizing air chamber; A dust collector, whose inlet is connected to the end of the extension section, whose gas outlet is connected to the fluidizing wind chamber, and whose solid outlet is connected to the bottom of the vertical section of the desulfurization tower through a chute; A booster fan and a heater are provided on the connecting pipe between the dust collector and the fluidizing air chamber; The angle between the extension section and the vertical section of the desulfurization tower is ≤8°; The bottom of the end of the extension section is connected to the dust hopper of the dust collector through a pipeline; A baffle is arranged at the end of the extension section, and the baffle extends upward from the bottom of the extension section.

2. The epitaxial circulating fluidized bed semi-dry desulfurization and dust removal system according to claim 1 is characterized in that: The ratio of the axial length of the vertical section and the extended section of the desulfurization tower is 1-3:

1.

3. The epitaxial circulating fluidized bed semi-dry desulfurization and dust removal system according to claim 1 is characterized in that: Types of fluidizing plates include perforated plates, hoods, fluidizing canvas, and metal sintered plates.

4. The epitaxial circulating fluidized bed semi-dry desulfurization and dust removal system according to claim 1 is characterized in that: The dust collector is a bag dust collector.

5. An epitaxial circulating fluidized bed semi-dry desulfurization and dust removal method of the epitaxial circulating fluidized bed semi-dry desulfurization and dust removal system according to claim 1, characterized in that: The steps include: The flue gas enters the desulfurization tower and is mixed with the desulfurizer sprayed in the vertical section of the desulfurization tower for desulfurization; The mixture of partially desulfurized flue gas and desulfurizer powder flows out from the top of the vertical section of the desulfurization tower and enters the extended section of the desulfurization tower to continue desulfurization; After the flue gas that meets the desulfurization standards enters the dust collector for dust removal, part of the flue gas flows back to the fluidized air chamber at the bottom of the extended section of the desulfurization tower, and fluidized air is blown into the extended section of the desulfurization tower to blow up the desulfurizer powder settled in the extended section.

6. The epitaxial circulating fluidized bed semi-dry desulfurization and dust removal method of the epitaxial circulating fluidized bed semi-dry desulfurization and dust removal system according to claim 5, characterized in that: The cross-sectional flow velocity of flue gas in the extended section of the desulfurization tower is 8-12m / s.

7. The epitaxial circulating fluidized bed semi-dry desulfurization and dust removal method of the epitaxial circulating fluidized bed semi-dry desulfurization and dust removal system according to claim 5, characterized in that: The wind pressure in the fluidizing air chamber is 90-110kPa.

8. The epitaxial circulating fluidized bed semi-dry desulfurization and dust removal method of the epitaxial circulating fluidized bed semi-dry desulfurization and dust removal system according to claim 5, characterized in that: The air temperature in the fluidizing air chamber is 100-120℃.

Images