CN106861412B - System and method for sharing and recycling high-calcium fly ash of multi-unit power station - Google Patents
System and method for sharing and recycling high-calcium fly ash of multi-unit power station Download PDFInfo
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- CN106861412B CN106861412B CN201710220980.XA CN201710220980A CN106861412B CN 106861412 B CN106861412 B CN 106861412B CN 201710220980 A CN201710220980 A CN 201710220980A CN 106861412 B CN106861412 B CN 106861412B
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- calcium fly
- calcium
- desulfurization
- flue gas
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- 239000010881 fly ash Substances 0.000 title claims abstract description 337
- 239000011575 calcium Substances 0.000 title claims abstract description 250
- 229910052791 calcium Inorganic materials 0.000 title claims abstract description 250
- 238000000034 method Methods 0.000 title claims abstract description 41
- 238000004064 recycling Methods 0.000 title claims abstract description 31
- 238000006477 desulfuration reaction Methods 0.000 claims abstract description 223
- 230000023556 desulfurization Effects 0.000 claims abstract description 222
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims abstract description 142
- 239000003546 flue gas Substances 0.000 claims abstract description 142
- 239000000428 dust Substances 0.000 claims abstract description 98
- 238000010521 absorption reaction Methods 0.000 claims abstract description 79
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims abstract description 67
- 239000000292 calcium oxide Substances 0.000 claims abstract description 53
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 claims abstract description 39
- 230000003009 desulfurizing effect Effects 0.000 claims abstract description 11
- 239000002956 ash Substances 0.000 claims description 66
- 239000006227 byproduct Substances 0.000 claims description 44
- 230000002745 absorbent Effects 0.000 claims description 35
- 239000002250 absorbent Substances 0.000 claims description 35
- 230000001105 regulatory effect Effects 0.000 claims description 27
- 238000012546 transfer Methods 0.000 claims description 24
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 13
- 239000006096 absorbing agent Substances 0.000 claims description 4
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 3
- 239000005864 Sulphur Substances 0.000 claims 1
- 239000003795 chemical substances by application Substances 0.000 abstract description 5
- 235000012255 calcium oxide Nutrition 0.000 description 48
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 24
- 238000007599 discharging Methods 0.000 description 11
- 239000000779 smoke Substances 0.000 description 10
- 230000008901 benefit Effects 0.000 description 9
- 235000019738 Limestone Nutrition 0.000 description 8
- JGIATAMCQXIDNZ-UHFFFAOYSA-N calcium sulfide Chemical compound [Ca]=S JGIATAMCQXIDNZ-UHFFFAOYSA-N 0.000 description 8
- 239000006028 limestone Substances 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 6
- 239000000920 calcium hydroxide Substances 0.000 description 6
- 235000011116 calcium hydroxide Nutrition 0.000 description 6
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 5
- 239000003245 coal Substances 0.000 description 5
- 238000002485 combustion reaction Methods 0.000 description 5
- 239000003344 environmental pollutant Substances 0.000 description 3
- 231100000719 pollutant Toxicity 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 239000011593 sulfur Substances 0.000 description 3
- 229910052717 sulfur Inorganic materials 0.000 description 3
- 239000002253 acid Substances 0.000 description 2
- 239000011449 brick Substances 0.000 description 2
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000001502 supplementing effect Effects 0.000 description 2
- 230000006978 adaptation Effects 0.000 description 1
- 238000000889 atomisation Methods 0.000 description 1
- 230000015271 coagulation Effects 0.000 description 1
- 238000005345 coagulation Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000003517 fume Substances 0.000 description 1
- 238000005469 granulation Methods 0.000 description 1
- 230000003179 granulation Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000012946 outsourcing Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 230000002277 temperature effect Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000010977 unit operation Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/48—Sulfur compounds
- B01D53/50—Sulfur oxides
- B01D53/508—Sulfur oxides by treating the gases with solids
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C10/00—Fluidised bed combustion apparatus
- F23C10/18—Details; Accessories
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J15/00—Arrangements of devices for treating smoke or fumes
- F23J15/006—Layout of treatment plant
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J15/00—Arrangements of devices for treating smoke or fumes
- F23J15/02—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2258/00—Sources of waste gases
- B01D2258/02—Other waste gases
- B01D2258/0283—Flue gases
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Biomedical Technology (AREA)
- Health & Medical Sciences (AREA)
- Combustion & Propulsion (AREA)
- Environmental & Geological Engineering (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Treating Waste Gases (AREA)
Abstract
The invention belongs to the field of flue gas treatment, and particularly relates to a system and a method for sharing and recycling high-calcium fly ash of a multi-unit power station. Each unit of the system comprises: the device comprises a circulating fluidized bed boiler, a front dust remover, a circulating fluidized bed dry desulfurization absorption tower, a rear dust remover and an induced draft fan; all units share one set of high-calcium fly ash distribution system, and the high-calcium fly ash distribution system can send the fly ash captured by the front dust remover into the circulating fluidized bed dry desulfurization absorption tower or discharge the fly ash according to the calcium oxide content of the fly ash. The invention takes the high-calcium fly ash as the desulfurizing agent of the circulating fluidized bed dry desulfurization process, and utilizes the high-calcium fly ash distribution system to select and regulate the high-calcium fly ash quantity entering the circulating fluidized bed dry desulfurization absorption tower of the plurality of generator sets and the low-calcium fly ash quantity discharged to the fly ash warehouse according to the desulfurization requirements of the plurality of generator sets and the calcium oxide content of the fly ash, thereby realizing the on-site high-efficiency recycling of the high-calcium fly ash.
Description
Technical Field
The invention belongs to the field of flue gas treatment, and particularly relates to a system and a method for sharing and recycling high-calcium fly ash of a multi-unit power station.
Background
The circulating fluidized bed boiler has the advantages of wide fuel adaptability, strong load adjusting capability, low pollutant emission concentration and the like. And 25% of the coal resources in China are high-sulfur coal with the sulfur content exceeding 2%, meanwhile, the accumulated gangue reaches 15 hundred million tons, and the circulating fluidized bed boiler has a huge application market in China. Since the introduction of foreign countries, the circulating fluidized bed boiler technology of China is continuously developed, and at present, china has 300 MW-level circulating fluidized bed boilers at most in the world, and 600 MW-level circulating fluidized bed boilers at the maximum in the world are built.
Because the combustion temperature of the circulating fluidized bed boiler is lower than that of the pulverized coal boiler and is about 850-950 ℃, the thermal NOx generated by combustion is less; meanwhile, the combustion temperature range of 850-950 ℃ is just the optimal reaction zone for calcium spraying and desulfurization in the furnace, and the circulating fluidized bed boiler SO is used for desulfurization in the furnace 2 Emissions can be controlled at relatively low levels. Along with the increasing requirements of China on the emission of flue gas pollutants in coal-fired power plants, the circulating fluidized bed boiler is widely applied.
In the desulfurization in the circulating fluidized bed boiler, limestone powder is used as a desulfurizing agent, and is put into the boiler, calcined into quicklime under the high temperature effect of coal combustion, and then mixed with SO in flue gas 2 And (3) reacting to generate calcium sulfate. In the process of desulfurization in the circulating fluidized bed boiler, the method canProduction of a composition containing CaSO 4 And fly ash of CaO; the sulfur-removing calcium-sulfur ratio in the furnace is different, and the content of calcium oxide in the fly ash is different. When the CaO content in the fly ash is lower than 10%, the fly ash is called low-calcium fly ash; when the content of the desulfurized calcium and sulfur in the furnace is high, the CaO content in the fly ash is higher than 10 percent, even up to 20 to 40 percent, and the fly ash is also called high-calcium fly ash. Research shows that the CaO content in the high-calcium fly ash is obviously higher than the national standard about brick making and concrete, even higher than the upper limit value required by brick and concrete manufacturers, and is difficult to comprehensively utilize, and the high-calcium fly ash can be treated only by adopting a gray field storage mode, so that a large amount of CaO is not utilized and is wasted.
Disclosure of Invention
In view of the above, the invention aims to provide a system and a method for sharing and recycling high-calcium fly ash of a multi-unit power station.
The invention provides a high-calcium fly ash sharing and recycling system of a multi-unit power station, each unit comprises:
a circulating fluidized bed boiler;
a flue gas inlet is connected with a flue gas outlet of the circulating fluidized bed boiler;
the flue gas inlet is connected with a flue gas outlet of the front dust remover;
a flue gas inlet is connected with a flue gas outlet of the circulating fluidized bed dry desulfurization absorption tower;
the induced draft fan is connected with the flue gas inlet and the flue gas outlet of the rear dust remover;
all units share one set of high-calcium fly ash distribution system, the inlet of the high-calcium fly ash distribution system is connected with the ash outlet of the front dust remover of each unit, and the high-calcium fly ash distribution system can send the fly ash trapped by the front dust remover into the circulating fluidized bed dry desulfurization absorption tower or discharge the fly ash according to the calcium oxide content of the fly ash.
Preferably, the high-calcium fly ash distribution system comprises a high-calcium fly ash distribution transfer station and a plurality of high-calcium fly ash bins; the ash inlet of the high-calcium fly ash distribution transfer station is connected with the ash outlet of the front dust remover of each unit, the ash outlet of the high-calcium fly ash distribution transfer station is connected with the ash inlet of the high-calcium fly ash bin of each unit, and the ash outlet of the high-calcium fly ash bin of each unit is respectively connected with the high-calcium fly ash inlet of the circulating fluidized bed dry desulfurization absorption tower of the unit; the first-stage distributing and conveying device and the middle storage and conveying regulating device are arranged on a connecting pipeline between an ash inlet of the high-calcium fly ash distributing transfer station and an ash outlet of a front dust remover of each unit; and a second-stage distribution conveying device is arranged on a connecting pipeline between the ash outlet of the high-calcium fly ash distribution transfer station and the ash inlet of the high-calcium fly ash bin of each unit.
Preferably, the high-calcium fly ash distribution system further comprises a fly ash warehouse, wherein an ash inlet of the fly ash warehouse is connected with an ash outlet of a front dust remover of each unit; the connecting pipeline between the ash inlet of the fly ash warehouse and the ash outlet of the front dust remover of each unit is provided with a primary distribution conveying device and an external discharge conveying and adjusting device.
Preferably, the system further comprises an auxiliary absorbent supply device, and a discharge port of the auxiliary absorbent supply device is connected with an auxiliary absorbent inlet of the circulating fluidized bed dry desulfurization absorption tower.
Preferably, the system further comprises desulfurization by-product recycling and discharge means; the ash inlet of the desulfurization byproduct circulation and discharge device is connected with the ash outlet of the rear dust remover, and the desulfurization byproduct circulation and discharge device can circulate the desulfurization byproducts trapped by the rear dust remover back into the circulating fluidized bed dry desulfurization absorption tower or discharge the desulfurization byproducts outside according to the requirements.
Preferably, the ash outlet of the high-calcium fly ash bin is connected with the high-calcium fly ash inlet of the circulating fluidized bed dry desulfurization tower; the connecting pipeline between the ash outlet of the high-calcium fly ash bin and the high-calcium fly ash inlet of the circulating fluidized bed dry desulfurization tower is also provided with a high-calcium fly ash metering device, a high-calcium fly ash feeding and adjusting device and a high-calcium fly ash feeding and conveying device.
The invention provides a method for sharing and recycling high-calcium fly ash of a multi-unit power station in the system according to the technical scheme, which comprises the following steps:
a) The method comprises the steps that in-furnace desulfurization flue gas generated by in-furnace desulfurization of circulating fluidized bed boilers of a plurality of generator sets is treated by a front dust remover to obtain fly ash and front dust-removed flue gas;
b) The fly ash is sent into a circulating fluidized bed dry desulfurization absorption tower of a plurality of generator sets or discharged outside through a high-calcium fly ash distribution system according to the content of calcium oxide and the flue gas desulfurization requirements of the plurality of generator sets;
c) Desulfurizing the front dedusting flue gas in a circulating fluidized bed dry desulfurization absorption tower by taking high-calcium fly ash as a desulfurization absorbent to obtain flue gas containing desulfurization byproducts;
d) And the flue gas containing the desulfurization byproducts is treated by a post-dust remover to obtain the desulfurization byproducts and post-dust-removal flue gas.
Preferably, the calcium oxide content of the high-calcium fly ash fed into the circulating fluidized bed dry desulfurization absorption tower is more than 10 wt%.
Preferably, SO in the desulfurization flue gas in the furnace 2 The concentration is higher than 500mg/Nm 3 And during the process, the auxiliary absorbent is sent into a circulating fluidized bed dry desulfurization absorption tower for auxiliary desulfurization.
Preferably, in step c), the desulphurised calcium sulphur ratio is not higher than 3.0.
Compared with the prior art, the invention provides a system and a method for sharing and recycling high-calcium fly ash of a multi-unit power station. Each unit of the system comprises: a circulating fluidized bed boiler; a flue gas inlet is connected with a flue gas outlet of the circulating fluidized bed boiler; the flue gas inlet is connected with a flue gas outlet of the front dust remover; a flue gas inlet is connected with a flue gas outlet of the circulating fluidized bed dry desulfurization absorption tower; the induced draft fan is connected with the flue gas inlet and the flue gas outlet of the rear dust remover; all units share one set of high-calcium fly ash distribution system, the inlet of the high-calcium fly ash distribution system is connected with the ash outlet of the front dust remover of each unit, and the high-calcium fly ash distribution system can send the fly ash trapped by the front dust remover into the circulating fluidized bed dry desulfurization absorption tower or discharge the fly ash according to the calcium oxide content of the fly ash. In the invention, the desulfurization flue gas in the circulating fluidized bed boiler generated by the desulfurization in the circulating fluidized bed boiler of a plurality of generator sets is treated by a front dust remover to obtain fly ash and front dust-removed flue gas; then, the high-calcium fly ash with high calcium oxide content is sent into a circulating fluidized bed dry desulfurization absorption tower of a plurality of generator sets through a high-calcium fly ash distribution system, and front dedusting flue gas is desulfurized in the circulating fluidized bed dry desulfurization absorption tower by taking the high-calcium fly ash as a desulfurization absorbent, so that flue gas containing desulfurization byproducts is obtained; finally, the flue gas containing the desulfurization byproducts is treated by a post-dust remover to obtain the desulfurization byproducts and post-dust-removal flue gas. The invention takes the high-calcium fly ash as the desulfurizing agent of the circulating fluidized bed dry desulfurization process, and utilizes the high-calcium fly ash distribution system to select and regulate the high-calcium fly ash amount in the circulating fluidized bed dry desulfurization absorption tower and the low-calcium fly ash amount discharged to the fly ash warehouse according to the desulfurization requirements of a plurality of generator sets and the calcium oxide content of the fly ash, so that the low-calcium fly ash with low calcium oxide content is sold and utilized, and sulfur dioxide in the flue gas is efficiently removed in the circulating fluidized bed dry desulfurization absorption tower, thereby the clean flue gas with ultra-low sulfur dioxide content is obtained by a plurality of units of the whole coal-fired power plant, the on-site high-efficiency recycling of the high-calcium fly ash is realized, and the comprehensive benefit of the thermal power unit is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a high-calcium fly ash sharing and recycling system of a multi-unit power station provided by the embodiment of the invention;
fig. 2 is a flow chart of the operation of the high calcium fly ash distribution system provided by the embodiment of the invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention provides a high-calcium fly ash sharing and recycling system of a multi-unit power station, each unit comprises:
a circulating fluidized bed boiler;
a flue gas inlet is connected with a flue gas outlet of the circulating fluidized bed boiler;
the flue gas inlet is connected with a flue gas outlet of the front dust remover;
a flue gas inlet is connected with a flue gas outlet of the circulating fluidized bed dry desulfurization absorption tower;
the induced draft fan is connected with the flue gas inlet and the flue gas outlet of the rear dust remover;
all units share one set of high-calcium fly ash distribution system, the inlet of the high-calcium fly ash distribution system is connected with the ash outlet of the front dust remover of each unit, and the high-calcium fly ash distribution system can send the fly ash trapped by the front dust remover into the circulating fluidized bed dry desulfurization absorption tower or discharge the fly ash according to the calcium oxide content of the fly ash.
Referring to fig. 1, fig. 1 is a flow chart of a high-calcium fly ash sharing and recycling system of a multi-unit power station provided by the embodiment of the invention. In fig. 1, 1 is a front dust remover, 2 is a high-calcium fly ash distribution system, 31 is a circulating fluidized bed dry desulfurization absorption tower, 32 is a rear dust remover, 3 is a circulating fluidized bed dry desulfurization dust remover, 4 is an induced draft fan, 33 is an auxiliary absorbent supply device, and 34 is a desulfurization byproduct circulation and discharge device; f1 is desulfurization flue gas in the furnace, F2 is front dust-removing flue gas, F3 is rear dust-removing flue gas, and L1 is atomization process water.
The high-calcium fly ash sharing and recycling system of the multi-unit power station comprises a circulating fluidized bed boiler, a front dust remover 1, a high-calcium fly ash distribution system 2, a circulating fluidized bed dry desulfurization absorption tower 31, a rear dust remover 32, an auxiliary absorbent supply device 33, a desulfurization byproduct circulation and discharge device 34 and an induced draft fan 4.
The flue gas inlet of the front dust remover 1 is connected with the flue gas outlet of the circulating fluidized bed boiler and is used for capturing fly ash in the desulfurization flue gas in the circulating fluidized bed boiler. In the invention, the front dust collector 1 is a dry dust collector, and specifically an electric dust collector, a bag dust collector or an electric bag dust collector can be selected, and the electric dust collector is preferred.
In the invention, the circulating fluidized bed dry desulfurization absorption tower 31 is used for further desulfurizing the front dust-removed flue gas F1, and the flue gas inlet of the circulating fluidized bed dry desulfurization absorption tower 31 is connected with the flue gas outlet of the front dust remover 1. In the invention, a high-calcium fly ash inlet is arranged on a circulating fluidized bed dry desulfurization absorption tower 31, and high-calcium fly ash with high calcium oxide content captured by a front dust remover 1 is conveyed to the high-calcium fly ash inlet of the circulating fluidized bed dry desulfurization absorption tower 31 through a high-calcium fly ash distribution system 2, and the high-calcium fly ash is used as a desulfurization absorbent. In the invention, the circulating fluidized bed dry desulfurization absorption tower 31 is also provided with an auxiliary absorbent inlet, and when the high-calcium fly ash is used alone as an absorbent to hardly meet the desulfurization requirement, the auxiliary absorbent is supplemented to the circulating fluidized bed dry desulfurization absorption tower 31 through the auxiliary absorbent inlet. In the present invention, an auxiliary absorbent supply device 33 is provided, and an auxiliary absorbent inlet of the circulating fluidized bed dry desulfurization absorption tower 31 is connected to a discharge port of the auxiliary absorbent supply device 33. In the invention, an atomized process water inlet is also arranged on the circulating fluidized bed dry desulfurization absorption tower 31, and is a channel for atomized process water L1 to enter the inner cavity of the circulating fluidized bed dry desulfurization absorption tower 31.
In the invention, the post-dust remover 32 is used for capturing desulfurization byproducts generated by desulfurization in the circulating fluidized bed dry desulfurization absorption tower 31, and the flue gas inlet of the post-dust remover 32 is connected with the flue gas outlet of the circulating fluidized bed dry desulfurization absorption tower 31. In the present invention, the post-dust collector 32 is a dry dust collector, and specifically, an electric dust collector, a bag dust collector or an electric bag dust collector may be selected, and is preferably a bag dust collector. In the present invention, the system preferably further includes a desulfurization by-product recycling and discharging device 34, and the ash outlet of the post-dust remover 32 is connected to the ash inlet of the desulfurization by-product recycling and discharging device 34. In the invention, the flue gas enters the rear dust remover 32, the desulfurization byproducts carried by the flue gas are captured and enter the desulfurization byproduct circulation and discharge device 34, and part of the flue gas returns to the circulating fluidized bed dry desulfurization absorption tower 31 for desulfurization again, so that the desulfurization efficiency and the utilization rate of unreacted CaO are improved; and the other part of desulfurization byproducts are discharged, and then are conveyed to an ash storage field or a comprehensive utilization point by an ash tank truck.
In the invention, a smoke outlet of the rear dust remover 32 is provided with the induced draft fan 4, the smoke outlet of the induced draft fan 4 is connected with a smoke inlet of a chimney, and the smoke treated by the rear dust remover 32 is conveyed to the chimney through the induced draft fan 4 and is discharged to the atmosphere through the chimney.
In the invention, the inlet of the high-calcium fly ash distribution system 2 is connected with the ash outlet trapped by the front dust remover 1 of the plurality of units, and the fly ash trapped by the front dust remover 1 can be sent into the circulating fluidized bed dry desulfurization absorption tower 31 of the plurality of units or discharged outside according to the calcium oxide content of the fly ash.
Referring to fig. 2, fig. 2 is a flow chart of the high calcium fly ash distribution system provided by an embodiment of the invention. In fig. 2, 1#, 2#, 3#, … and n# are 1#, 2#, 3#, … and n# generator sets of the same coal-fired power plant; 1 is a front dust remover, 31 is a circulating fluidized bed dry desulfurization absorption tower; a1 is a primary distribution conveying device, A21 is an outward discharge conveying regulating device, A22 is a middle storage conveying regulating device, A23 is an outward sales regulating device, A24 is an emergency outward discharge regulating device, A31 is a fly ash warehouse, A32 is a high-calcium fly ash distribution transfer station, A2 is a secondary distribution conveying device, A33 is a high-calcium fly ash warehouse, A3 is a high-calcium fly ash metering device, A26 is a high-calcium fly ash feeding regulating device, and A4 is a high-calcium fly ash feeding conveying device.
The high-calcium fly ash distribution system 2 preferably comprises a high-calcium fly ash distribution transfer station A32 for storing high-calcium fly ash captured by the front dust collector 1 of the plurality of units and a high-calcium fly ash bin A33 of the plurality of units; the ash inlet of the high-calcium fly ash distribution transfer station A32 is connected with the ash outlet of the front dust collector 1 of each unit, the ash outlet of the high-calcium fly ash distribution transfer station A32 is connected with the ash inlet of the high-calcium fly ash bin A33 of each unit, and the ash outlet of the high-calcium fly ash bin A33 of each unit is respectively connected with the high-calcium fly ash inlet of the circulating fluidized bed dry desulfurization absorption tower 31 of the unit. In the invention, a first-stage distribution conveying device A1 and a middle storage conveying regulating device A22 are preferably arranged on a connecting pipeline of an ash inlet of a high-calcium fly ash distribution transfer station A32 and an ash outlet of a front dust remover 1 of each unit, and are used for regulating the high-calcium fly ash storage conveying capacity of each unit meeting the conditions. In the invention, a secondary distribution conveying device A2 is preferably arranged on a connecting pipeline between the ash outlet of the high-calcium fly ash distribution transfer station A32 and the ash inlet of the high-calcium fly ash bin A33 of each unit, and is used for conveying the high-calcium fly ash according to the requirement of each unit. In the invention, a high-calcium fly ash metering device A3, a high-calcium fly ash feeding and adjusting device A26 and a high-calcium fly ash feeding and conveying device A4 are preferably arranged on a connecting pipeline between the ash outlet of a high-calcium fly ash bin A33 of each unit and the high-calcium fly ash inlet of a circulating fluidized bed dry desulfurization absorption tower 31 of the unit, and are used for accurately metering and adjusting the high-calcium fly ash feeding amount according to the flue gas desulfurization requirements of each unit. In the invention, the high-calcium fly ash distribution transfer station A32 is preferably also provided with an emergency discharge port, and the emergency discharge port is connected with an emergency discharge regulating device A24 for discharging the high-calcium fly ash under emergency conditions such as unit fault maintenance and the like.
In the invention, the high-calcium fly ash distribution system 2 preferably further comprises a fly ash warehouse A31 for storing the low-calcium fly ash with low calcium oxide content captured by the front dust collectors 1 of the plurality of units, and an ash inlet of the fly ash warehouse A31 is connected with an ash outlet of the front dust collector 1 of each unit. In the invention, a first-stage distributing and conveying device A1 and an outward-discharging and conveying regulating device A21 are preferably arranged on a pipeline connecting an ash inlet of a fly ash warehouse A31 with an ash outlet of a front dust collector 1 of each unit and are used for regulating and controlling the outward-discharging and conveying of low-calcium fly ash. In the invention, the first-stage distribution conveying device A1 is preferably arranged on a common pipeline of the fly ash warehouse A31 and the high-calcium fly ash distribution transfer station A32 connected with the front dust remover 1 of each unit, namely the storage conveying device and the discharge conveying device of the fly ash of each unit share the same first-stage distribution conveying device.
Therefore, in the invention, the fly ash can have a plurality of different directions according to the content of calcium oxide in the fly ash of each unit and the flue gas desulfurization requirement of each unit. In one embodiment provided by the invention, fly ash travel may be regulated in the following manner:
when the detected value of the calcium oxide content in the fly ash trapped by the front dust remover 1 of a certain unit is lower than a required value, if the detected value is lower than 10%, starting an outward-discharging conveying regulating device A21, closing a middle-storing conveying regulating device A22, discharging low-calcium fly ash to a fly ash warehouse A31, and transporting and selling the low-calcium fly ash by an ash tank truck; when the detected value of the calcium oxide content in the fly ash meets the requirement, if the detected value is higher than 10%, the discharging conveying regulating device A21 is closed, the middle storage conveying regulating device A22 is started, and the high-calcium fly ash is conveyed to the high-calcium fly ash distribution transfer station A32 for storage. The fly ash trapped by other units can be selectively stored or discharged in the same control mode. In actual operation, the calcium oxide content of the fly ash under different boiler loads and in-furnace desulfurization working conditions can be detected and analyzed in advance, a corresponding curve of the unit operation working conditions and the calcium oxide content of the fly ash is drawn, and accordingly control logic of fly ash storage or discharge is established.
When the storage capacity of the high-calcium fly ash in the high-calcium fly ash bin of a certain unit is insufficient, a secondary distribution conveying device A2 of the unit is started, and the high-calcium fly ash stored in the high-calcium fly ash distribution transfer station A32 is conveyed to the high-calcium fly ash bin A33 of the unit. Meanwhile, according to the flue gas desulfurization requirement of the unit, the high-calcium fly ash feeding regulating device A26 of the unit is regulated, and a certain amount of high-calcium fly ash is fed into the circulating fluidized bed dry desulfurization absorption tower 31 of the unit after passing through the high-calcium fly ash metering device A3, the high-calcium fly ash feeding regulating device A26 and the high-calcium fly ash feeding conveying device A4. In the invention, the high-calcium fly ash bin A33 of each unit preferably stores the high-calcium fly ash meeting the 3-day consumption of flue gas desulfurization of the unit. When the high-calcium fly ash bin A33 of the unit does not need to be fed, the secondary distribution conveying device A2 of the unit is closed, and meanwhile, the secondary distribution conveying devices A2 of other units are opened according to the material level conditions of the high-calcium fly ash bins of the other units, so that the flue gas desulfurization requirements of the multiple units are met. The sharing and the distribution of the high-calcium fly ash of a plurality of units of the same coal-fired power plant are realized through the processes, and the recycling utilization rate of the high-calcium fly ash is improved.
In the invention, desulfurization flue gas in a furnace generated by desulfurization in a circulating fluidized bed boiler of a plurality of units is treated by a front dust remover of each unit to obtain fly ash and front dust removal flue gas; then, the high-calcium fly ash with high calcium oxide content is sent into a circulating fluidized bed dry desulfurization absorption tower of each unit through a high-calcium fly ash distribution system, and the front dedusting flue gas is desulfurized in the circulating fluidized bed dry desulfurization absorption tower by taking the high-calcium fly ash as a desulfurization absorbent to obtain flue gas containing desulfurization byproducts; finally, the flue gas containing the desulfurization byproducts is treated by a post-dust remover to obtain the desulfurization byproducts and post-dust-removal flue gas. The invention takes the high-calcium fly ash as the desulfurizing agent of the circulating fluidized bed dry desulfurization process, and utilizes the high-calcium fly ash distribution system to regulate and control the amount of the high-calcium fly ash entering the circulating fluidized bed dry desulfurization absorption towers of a plurality of units, so that the high-calcium fly ash can efficiently remove sulfur dioxide in the flue gas in the circulating fluidized bed dry desulfurization absorption towers, thereby obtaining clean flue gas with ultralow sulfur dioxide content, realizing the on-site high-efficiency recycling of the high-calcium fly ash, and improving the comprehensive benefit of the thermal power unit.
The invention provides a method for sharing and recycling high-calcium fly ash of a multi-unit power station in the system according to the technical scheme, which comprises the following steps:
a) The method comprises the steps that in-furnace desulfurization flue gas generated by in-furnace desulfurization of circulating fluidized bed boilers of a plurality of generator sets is treated by a front dust remover to obtain fly ash and front dust-removed flue gas;
b) The fly ash is sent into a circulating fluidized bed dry desulfurization absorption tower of a plurality of generator sets or discharged outside through a high-calcium fly ash distribution system according to the content of calcium oxide and the flue gas desulfurization requirements of the plurality of generator sets;
c) Desulfurizing the front dedusting flue gas in a circulating fluidized bed dry desulfurization absorption tower by taking high-calcium fly ash as a desulfurization absorbent to obtain flue gas containing desulfurization byproducts;
d) And the flue gas containing the desulfurization byproducts is treated by a post-dust remover to obtain the desulfurization byproducts and post-dust-removal flue gas.
In the method provided by the invention, the in-furnace desulfurization flue gas generated by in-furnace desulfurization of the circulating fluidized bed boiler is firstly treated by a front-end dust remover. Wherein SO in the desulfurization flue gas in the furnace 2 The concentration is preferably below 2000mg/Nm 3 More preferably less than 500mg/Nm 3 The method comprises the steps of carrying out a first treatment on the surface of the The temperature of the desulfurization flue gas in the furnace is preferably 100 to 150 ℃, more preferably 120 to 140 ℃. In the embodiment provided by the invention, the flue gas amount of the desulfurization flue gas in the furnace is 500000 ～ 2000000m 3 /h, in particular 1750000 and 810000m 3 And/h. And the flue gas is treated by a front dust remover to obtain fly ash and front dust removing flue gas.
After the fly ash and the front dedusting smoke are obtained, the high-calcium fly ash with high calcium oxide content is sent into a circulating fluidized bed dry desulfurization absorption tower through a high-calcium fly ash distribution system; the front dedusting flue gas is desulfurized in a circulating fluidized bed dry desulfurization absorption tower by taking high-calcium fly ash as a desulfurization absorbent. In the invention, the high-calcium fly ash distribution system preferably sends the high-calcium fly ash with the calcium oxide content of more than 10 weight percent into a circulating fluidized bed dry desulfurization absorption tower, and more preferably sends the high-calcium fly ash with the calcium oxide content of 20-40 weight percent. In the present invention, the desulfurization calcium-sulfur ratio of the high-calcium fly ash as a desulfurization absorbent is preferably not higher than 3.0, more preferably 2.5. In the present invention, when desulfurization needs cannot be satisfied by using only high-calcium fly ash as a desulfurization absorber, it is preferable to add an auxiliary absorber, including but not limited to slaked lime, into the circulating fluidized bed dry desulfurization absorber. In the embodiments provided by the invention, it is preferred that SO is present in the flue gas desulfurization in the furnace 2 The concentration is higher than 500mg/Nm 3 When the auxiliary absorbent is fed into the circulating fluidized bed dry desulfurization absorberAnd carrying out auxiliary desulfurization in the tower. In the embodiment provided by the invention, in the desulfurization process, the atomized process water consumption of a single circulating fluidized bed dry desulfurization absorption tower is 12-30 t/h; the operation temperature of the circulating fluidized bed dry desulfurization absorption tower is preferably 70-90 ℃, and can be specifically 80 ℃ or 85 ℃; the bed pressure drop of the circulating fluidized bed dry desulfurization absorption tower is preferably 0.6 to 1.4kPa, and may be specifically 1.1kPa. And treating the front dedusting flue gas by a circulating fluidized bed dry desulfurization absorption tower to obtain flue gas containing desulfurization byproducts.
And after the flue gas containing the desulfurization byproducts is obtained, the flue gas is treated by a post-dust remover to obtain the desulfurization byproducts and post-dust-removal flue gas. And the post-dedusting flue gas is discharged to the external atmosphere through a chimney. In one embodiment provided by the invention, the SO of the post-dedusting flue gas 2 Concentration of less than 35mg/Nm 3 。
The method provided by the invention takes the high-calcium fly ash as a desulfurizing agent of the circulating fluidized bed dry desulfurization process, selects the high-calcium fly ash with the calcium oxide content meeting the conditions by utilizing the high-calcium fly ash distribution system, shares and distributes the high-calcium fly ash meeting the conditions according to the flue gas desulfurization requirements of a plurality of units in the same power station, regulates and controls the amount of the high-calcium fly ash entering the circulating fluidized bed dry desulfurization absorption tower of each unit, and conveys the high-calcium fly ash into the circulating fluidized bed dry desulfurization absorption tower of each unit according to the running condition of each unit to efficiently remove sulfur dioxide in the flue gas, thereby obtaining clean flue gas with ultra-low sulfur dioxide content, realizing the on-site high-efficiency recycling utilization of the high-calcium fly ash and improving the comprehensive benefit of a thermal power unit.
Compared with the prior art, the high-calcium fly ash sharing and recycling system and method for the multi-unit power station provided by the invention have the following specific advantages:
1) The high-calcium fly ash sharing and recycling method for the multi-unit power station provided by the invention has the advantages that after the fly ash generated by the circulating fluidized bed boiler of the multi-unit power station is captured by the front dust remover, the high-calcium fly ash is selected, stored and distributed by the high-calcium fly ash distribution system, and the high-calcium fly ash with high calcium oxide content is sent into the circulation of each unitThe fluidized bed dry desulfurizing and dedusting device uses the dense bed layer and sprayed atomized water film in the circulating fluidized bed dry desulfurizing and absorbing tower to mix with SO in fume 2 The acid gas generates rapid ion reaction to realize SO in the flue gas 2 And the high-efficiency removal of pollutants.
2) The high-calcium fly ash distribution system and the auxiliary absorbent supply device play a role in regulation at the same time: on one hand, according to the flue gas desulfurization requirements of a plurality of units, the content of calcium oxide in the fly ash of each unit is controlled by controlling the desulfurization working condition in the furnace of each unit, so that the proportion of low-calcium fly ash discharged outside the whole power station and the proportion of high-calcium fly ash subjected to flue gas desulfurization are regulated, and the comprehensive utilization benefit of the high-calcium fly ash is improved to the greatest extent; on the other hand, according to the concentration range of the sulfur dioxide in the flue gas at the inlet and the concentration range of the sulfur dioxide in the flue gas at the outlet of the circulating fluidized bed dry desulfurization absorption tower of each unit, the conveying amount of the high-calcium fly ash and the supplementing amount of the auxiliary absorbent are controlled, the problem of exceeding standard discharge caused by insufficient high-calcium fly ash removal capacity when the concentration of the sulfur dioxide in the flue gas is too high is avoided, and the problem of low utilization rate of calcium oxide caused by excessive high-calcium fly ash input under the working condition of low sulfur dioxide at the inlet can be avoided.
3) When a plurality of units are simultaneously built in one coal-fired power plant, the high-calcium fly ash demand of each unit can be balanced through the high-calcium fly ash distribution system, and the utilization rate of the high-calcium fly ash can be improved to the greatest extent. More importantly, the high-calcium fly ash sharing and recycling system of the multi-unit power station provided by the invention is not influenced by the arrangement form of the unit induced draft fan, and has strong field adaptability.
4) By utilizing the coagulation and granulation characteristics of the circulating fluidized bed dry desulfurization absorption tower, the rear dust remover realizes the efficient collection of fine smoke particles and ensures the ultra-low emission of smoke. The desulfurization byproducts trapped by the rear dust remover are sent back to the absorption tower through the desulfurization byproduct circulation and discharge device, and calcium oxide which is not completely reacted can further participate in desulfurization reaction in the tower, so that the desulfurization efficiency of the desulfurization absorption tower and the utilization rate of calcium oxide in the high-calcium fly ash are effectively ensured.
For clarity, the following examples are provided in detail.
Example 1
High-calcium fly ash sharing and resource utilization system of multi-unit power station
The high-calcium fly ash sharing and recycling system of the multi-unit power station shown in fig. 1 comprises a circulating fluidized bed boiler, a front dust remover 1, a high-calcium fly ash distribution system 2, a circulating fluidized bed dry desulfurization absorption tower 31, a rear dust remover 32, an induced draft fan 4 and a chimney, which are sequentially arranged along the flow direction of flue gas.
In the embodiment, the ash outlet of the front dust collector 1 of the plurality of units is connected with a first-stage distribution and conveying device A1, and the outlet of the first-stage distribution and conveying device A1 of each unit is connected with an outer row conveying regulating device A21 and a middle storage conveying regulating device A22 in parallel; the discharge conveying adjusting device A21 of each unit is connected with a common fly ash warehouse A31; the middle storage and conveying adjusting device A22 of each unit is connected with an ash inlet of a common high-calcium fly ash distribution transfer station A32, and an ash outlet of the high-calcium fly ash distribution transfer station A32 is also connected with a secondary distribution and conveying device A2 of each unit; the secondary distribution conveying device A2 of each unit is connected with an ash inlet of a high-calcium fly ash bin A33 of the unit, and an ash outlet of the high-calcium fly ash bin A33 of each unit is connected with a high-calcium fly ash inlet of a circulating fluidized bed dry desulfurization absorption tower 31 of the unit; along the high-calcium fly ash conveying direction, a high-calcium fly ash metering device A3, a high-calcium fly ash feeding and adjusting device A26 and a high-calcium fly ash feeding and conveying device A4 are sequentially arranged on a connecting pipeline of an ash outlet of a high-calcium fly ash bin A33 and a high-calcium fly ash inlet of a circulating fluidized bed dry desulfurization absorption tower 31. In this embodiment, the above-described devices constitute the high calcium fly ash distribution system 2 of this embodiment, as shown in FIG. 2.
In this embodiment, the circulating fluidized bed dry desulfurization absorption tower 31, the post-dust remover 32 and the pipeline connected therebetween together form the circulating fluidized bed dry desulfurization dust remover 3. An atomized process water L1 inlet is arranged on the circulating fluidized bed dry desulfurization absorption tower 31 of each unit; in this embodiment, an auxiliary absorbent supply 33 and desulfurization by-product recycle and discharge system 34 are also included.
The specific working process of the high-calcium fly ash sharing and recycling system of the multi-unit power station provided by the embodiment is as follows:
firstly, limestone powder is put into a circulating fluidized bed boiler, the limestone powder is calcined in the boiler to generate calcium oxide, then the calcium oxide participates in the desulfurization reaction in the boiler, and fly ash formed after coal combustion and in-boiler desulfurization enters a front dust remover 1 along with in-boiler desulfurization flue gas F1, so that most of the fly ash is captured. The front dust-removing flue gas F2 enters a circulating fluidized bed dry desulfurization dust-removing device 3 at the tail part, and the rear dust-removing flue gas F3 after desulfurization dust-removing purification is discharged out of a chimney under the action of a desulfurization induced draft fan 4.
The fly ash trapped by the front dust collector 1 enters the high-calcium fly ash distribution system 2. Under the action of the first-stage distributing and conveying device A1, the fly ash can have a plurality of different directions. When the content of calcium oxide in the fly ash is lower than 10wt%, opening an outward discharge conveying regulating device A21, closing a middle storage conveying regulating device A22, discharging the low-calcium fly ash to a fly ash warehouse A31, and transporting and selling the low-calcium fly ash by an ash tank truck; when the content of calcium oxide in the fly ash meets the requirement, if the content of calcium oxide in the fly ash is higher than 10%, the discharging conveying regulating device A21 is closed, the middle storage conveying regulating device A22 is opened, and the high-calcium fly ash is conveyed to the high-calcium fly ash distribution transfer station A32 for storage.
When the high-calcium fly ash bin A33 of a certain unit is insufficient in high-calcium fly ash storage capacity, a secondary distribution conveying device A2 of the unit is started, and the high-calcium fly ash stored in the high-calcium fly ash distribution transfer station A32 is conveyed to the high-calcium fly ash bin A33 of the unit. Meanwhile, according to the sulfur dioxide concentration of the front dust-removing flue gas F2 and the rear dust-removing flue gas F3 of the unit, the high-calcium fly ash feeding adjusting device A26 of the unit is adjusted, a certain amount of high-calcium fly ash is fed into the circulating fluidized bed dry desulfurization absorption tower 31 of the unit after passing through the high-calcium fly ash metering device A3, the high-calcium fly ash feeding adjusting device A26 and the high-calcium fly ash feeding conveying device A4, and atomized process water L1 and SO in the flue gas are sprayed 2 Quick ion reaction of the acid gas and removing SO in the flue gas 2 。
When the high-calcium fly ash bin A33 of the unit does not need to be fed, the secondary distribution conveying device A2 of the unit is closed, and meanwhile, the secondary distribution conveying devices A2 of other units are opened according to the material level conditions of the high-calcium fly ash bins of the other units so as to simultaneously meet the flue gas desulfurization requirements of the multiple units. The sharing and the distribution of the high-calcium fly ash of a plurality of units of the same power station are realized through the above processes.
When the absorption tower is at the inlet SO 2 The concentration is higher than 500mg/Nm 3 When the auxiliary absorbent supply device 33 is started, the auxiliary absorbent is put into the circulating fluidized bed dry desulfurization absorption tower 31 through the auxiliary absorbent supply device 33 to participate in auxiliary desulfurization, SO that the inlet SO of a chimney is ensured 2 The concentration meets the emission requirements.
The desulfurized flue gas enters a rear dust remover 32, desulfurization byproducts carried by the flue gas are captured, and a part of the desulfurization byproducts are returned to the circulating fluidized bed dry desulfurization absorption tower 31 for re-desulfurization through a desulfurization byproduct circulation and discharge device 34, so that the desulfurization efficiency and the utilization rate of unreacted calcium oxide are improved; a portion of the desulfurization byproducts are exhausted through a desulfurization byproduct recycling and exhaust device 34 and transported to a designated location by the ash tanker.
Example 2
In the system provided in example 1, high-calcium fly ash sharing and resource utilization of a multi-unit power station are performed, and a single 300 MW-level unit of a certain power station is taken as an example, and the specific implementation conditions are as follows:
the 300 MW-level scale circulating fluidized bed boiler provides raw flue gas, and the raw flue gas SO is not desulfurized in the boiler 2 At a concentration of 2000mg/Nm 3 SO in raw flue gas after desulfurization in furnace 2 The concentration was 480mg/Nm 3 The flue gas temperature is 138 ℃, and the flue gas volume is 1750000m 3 And/h. The CaO content of the high-calcium fly ash after desulfurization in the furnace is 15 to 23 weight percent. And conveying the high-calcium fly ash into an absorption tower, wherein the operating temperature of the absorption tower is kept at 85 ℃ during operation, the pressure drop of the bed layer of the absorption tower is 1.1kPa, the consumption of the high-calcium fly ash is 6.5t/h, the consumption of atomized process water is 26t/h, and the supplementary absorbent supplementing amount is zero. After treatment, SO is obtained 2 At a concentration of 34mg/Nm 3 Has remarkable desulfurization effect.
Example 3
In the system provided in example 1, high-calcium fly ash sharing and resource utilization of a multi-unit power station are carried out, and a self-contained power station built with a 6X 100MW circulating fluidized bed boiler unit is taken as an example, and the sulfur dioxide content requirement at the inlet of a chimney is not higher than 35mg/Nm 3 The specific implementation conditions are as follows:
the working condition smoke volume of each 100MW boiler is 810000m 3 Per hour, humidity-standard smoke volume 490000m 3 Per hour, dry standard smoke volume 450000m 3 And/h, SO in raw flue gas when the furnace is not desulfurized 2 At a concentration of 4000mg/Nm 3 The concentration of the fly ash in the raw flue gas is 20000mg/Nm when the furnace is not desulfurized 3 。
According to the result of the in-furnace desulfurization test, when the in-furnace desulfurization calcium-sulfur ratio is 1.0, the in-furnace desulfurization efficiency is 50%, the CaO content in the fly ash is less than 3.0%, the in-furnace desulfurization calcium-sulfur ratio belongs to the category of low-calcium fly ash, the in-furnace desulfurization calcium-sulfur ratio can be used for sale, and SO in the flue gas after the front dust remover is arranged 2 The content is 2000mg/Nm 3 The method comprises the steps of carrying out a first treatment on the surface of the When the desulfurization calcium-sulfur ratio in the furnace is 2.0, the desulfurization efficiency in the furnace is 75%, the CaO content in the fly ash is more than 10.0%, the fly ash belongs to the category of high-calcium fly ash, the fly ash cannot be sold and utilized, and SO in the flue gas after the front dust remover is arranged 2 The content is 1000mg/Nm 3 The method comprises the steps of carrying out a first treatment on the surface of the When the desulfurization calcium-sulfur ratio in the furnace is 3.0, the desulfurization efficiency in the furnace is 90%, the CaO content in the fly ash is more than 20.0%, the fly ash belongs to the category of high-calcium fly ash, the fly ash cannot be sold and utilized, and SO in the flue gas after the front dust remover is arranged 2 The content is 400mg/Nm 3 。
By adopting the high-calcium fly ash sharing and recycling system of the multi-unit power station, 1 unit of the 6X 100MW circulating fluidized bed boiler unit selects 90% of in-furnace desulfurization efficiency, the fly ash generated by in-furnace desulfurization of the unit is high-calcium fly ash, and the high-calcium fly ash is shared and distributed to all circulating fluidized bed dry desulfurization absorption towers of the 6 100MW units through a high-calcium fly ash distribution system; the other 5 100MW units select 50% of desulfurization efficiency in the furnace, and SO in the flue gas after desulfurization in the furnace 2 The concentration is high, the high-calcium fly ash has insufficient flue gas desulfurization capability, and the outsourcing slaked lime is adopted as an auxiliary absorbent for auxiliary desulfurization. The fly ash trapped by the front dust remover of the 5 100MW units is lowAnd (5) discharging the calcium fly ash, and conveying the calcium fly ash to a fly ash warehouse for sale and utilization.
The high-calcium fly ash sharing and recycling system of the multi-unit power station is not adopted, and a 6X 100MW circulating fluidized bed boiler unit can only adopt a traditional desulfurization scheme, and the following three schemes with 50% -90% of desulfurization efficiency in the furnace are taken as examples:
1) Limestone desulfurization is carried out in a furnace, the CaO content of the fly ash is less than 3.0%, the fly ash is sold, and slaked lime is desulfurized after the furnace;
2) In the furnace, limestone desulfurization is carried out, the CaO content of the fly ash is more than 10.0%, the fly ash is piled up, and slaked lime is desulfurized after the furnace;
3) Limestone desulfurization is carried out in a furnace, the CaO content of the fly ash is more than 20.0%, the fly ash is piled up, and slaked lime is desulfurized after the furnace;
the local limestone price is 150 yuan/ton, the slaked lime price is 600 yuan/ton, and the fly ash selling price is 30 yuan/ton. Each unit was operated for 7000 hours each year.
The high-calcium fly ash sharing and recycling system of the multi-unit power station of the invention consumes 3.8 ten thousand tons of auxiliary absorbent and 18 ten thousand tons of limestone each year, and can sell 41 ten thousand tons of fly ash, compared with the three schemes without the invention, the self-contained power station of the 6X 100MW unit has the advantages of saving the running cost by 440-5400 ten thousand yuan, and having remarkable economic benefit.
The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.
Claims (9)
1. A high-calcium fly ash sharing and resource utilization system of a multi-unit power station comprises:
a circulating fluidized bed boiler;
a flue gas inlet is connected with a flue gas outlet of the circulating fluidized bed boiler;
the flue gas inlet is connected with a flue gas outlet of the front dust remover;
a flue gas inlet is connected with a flue gas outlet of the circulating fluidized bed dry desulfurization absorption tower;
the induced draft fan is connected with the flue gas inlet and the flue gas outlet of the rear dust remover;
all units share a set of high-calcium fly ash distribution system, the inlet of the high-calcium fly ash distribution system is connected with the ash outlet of the front dust remover of each unit, and the high-calcium fly ash distribution system can send the fly ash trapped by the front dust remover into the circulating fluidized bed dry desulfurization absorption tower or discharge the fly ash according to the calcium oxide content of the fly ash;
the high-calcium fly ash distribution system comprises a high-calcium fly ash distribution transfer station and a plurality of high-calcium fly ash bins; the ash inlet of the high-calcium fly ash distribution transfer station is connected with the ash outlet of the front dust remover of each unit, the ash outlet of the high-calcium fly ash distribution transfer station is connected with the ash inlet of the high-calcium fly ash bin of each unit, and the ash outlet of the high-calcium fly ash bin of each unit is respectively connected with the high-calcium fly ash inlet of the circulating fluidized bed dry desulfurization absorption tower of the unit; the first-stage distributing and conveying device and the middle storage and conveying regulating device are arranged on a connecting pipeline between an ash inlet of the high-calcium fly ash distributing transfer station and an ash outlet of a front dust remover of each unit; and a second-stage distribution conveying device is arranged on a connecting pipeline between the ash outlet of the high-calcium fly ash distribution transfer station and the ash inlet of the high-calcium fly ash bin of each unit.
2. The system of claim 1, wherein the high calcium fly ash distribution system further comprises a fly ash silo, wherein an ash inlet of the fly ash silo is connected with an ash outlet of a front-end dust collector of each unit; the connecting pipeline between the ash inlet of the fly ash warehouse and the ash outlet of the front dust remover of each unit is provided with a primary distribution conveying device and an external discharge conveying and adjusting device.
3. The system of claim 1, further comprising an auxiliary absorbent supply, wherein a discharge port of the auxiliary absorbent supply is connected to an auxiliary absorbent inlet of the circulating fluidized bed dry desulfurization absorber.
4. The system of claim 1, further comprising desulfurization by-product recycle and discharge means; the ash inlet of the desulfurization byproduct circulation and discharge device is connected with the ash outlet of the rear dust remover, and the desulfurization byproduct circulation and discharge device can circulate the desulfurization byproducts trapped by the rear dust remover back into the circulating fluidized bed dry desulfurization absorption tower or discharge the desulfurization byproducts outside according to the requirements.
5. The high calcium fly ash distribution system according to claim 1, wherein the ash outlet of the high calcium fly ash bin is connected to the high calcium fly ash inlet of the circulating fluidized bed dry desulfurization tower; the connecting pipeline between the ash outlet of the high-calcium fly ash bin and the high-calcium fly ash inlet of the circulating fluidized bed dry desulfurization tower is also provided with a high-calcium fly ash metering device, a high-calcium fly ash feeding and adjusting device and a high-calcium fly ash feeding and conveying device.
6. A method of sharing and recycling high calcium fly ash of a multi-unit power plant in the system of any one of claims 1 to 5, comprising the steps of:
a) The method comprises the steps that in-furnace desulfurization flue gas generated by in-furnace desulfurization of circulating fluidized bed boilers of a plurality of generator sets is treated by a front dust remover to obtain fly ash and front dust-removed flue gas;
b) The fly ash is sent into a circulating fluidized bed dry desulfurization absorption tower of a plurality of generator sets or discharged outside through a high-calcium fly ash distribution system according to the content of calcium oxide and the flue gas desulfurization requirements of the plurality of generator sets;
c) Desulfurizing the front dedusting flue gas in a circulating fluidized bed dry desulfurization absorption tower by taking high-calcium fly ash as a desulfurization absorbent to obtain flue gas containing desulfurization byproducts;
d) And the flue gas containing the desulfurization byproducts is treated by a post-dust remover to obtain the desulfurization byproducts and post-dust-removal flue gas.
7. The method according to claim 6, wherein the calcium oxide content of the high-calcium fly ash fed into the circulating fluidized bed dry desulfurization absorption tower is 10wt% or more.
8. The method of claim 6, wherein the in-furnace desulfurized flue gas is SO 2 The concentration is higher than 500mg/Nm 3 And during the process, the auxiliary absorbent is sent into a circulating fluidized bed dry desulfurization absorption tower for auxiliary desulfurization.
9. The method of claim 6, wherein in step c), the desulphurized calcium to sulphur ratio is not higher than 3.0.
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| CN108043204B (en) * | 2017-12-20 | 2024-01-26 | 上海电力学院 | High-calcium pulverized coal flue gas desulfurization system and application thereof |
| CN108036327B (en) * | 2018-01-20 | 2022-02-15 | 北京中力信达环保工程有限公司 | Small-size energy-conserving high-efficient domestic waste incineration disposal system |
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| WO2014183364A1 (en) * | 2013-05-14 | 2014-11-20 | 中国环境科学研究院 | High-efficiency method for removing sulfur and mercury of coal-fired flue gas, and apparatus thereof |
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| WO2014183364A1 (en) * | 2013-05-14 | 2014-11-20 | 中国环境科学研究院 | High-efficiency method for removing sulfur and mercury of coal-fired flue gas, and apparatus thereof |
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