CN116817261A - Intermediate storage bin type hot furnace smoke drying steel ball milling powder making system and method - Google Patents
Intermediate storage bin type hot furnace smoke drying steel ball milling powder making system and method Download PDFInfo
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- CN116817261A CN116817261A CN202310477717.4A CN202310477717A CN116817261A CN 116817261 A CN116817261 A CN 116817261A CN 202310477717 A CN202310477717 A CN 202310477717A CN 116817261 A CN116817261 A CN 116817261A
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- 239000000843 powder Substances 0.000 title claims abstract description 191
- 238000001035 drying Methods 0.000 title claims abstract description 83
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 63
- 239000010959 steel Substances 0.000 title claims abstract description 63
- 238000000034 method Methods 0.000 title claims abstract description 32
- 239000000779 smoke Substances 0.000 title claims abstract description 25
- 238000000498 ball milling Methods 0.000 title claims abstract description 16
- 238000012432 intermediate storage Methods 0.000 title claims description 5
- 239000003245 coal Substances 0.000 claims abstract description 88
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims abstract description 51
- 239000003546 flue gas Substances 0.000 claims abstract description 51
- 238000000227 grinding Methods 0.000 claims abstract description 19
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 15
- 239000001301 oxygen Substances 0.000 claims abstract description 15
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 15
- 230000008569 process Effects 0.000 claims abstract description 13
- 239000000428 dust Substances 0.000 claims abstract description 5
- 239000007789 gas Substances 0.000 claims description 17
- 238000010298 pulverizing process Methods 0.000 claims description 14
- 238000007664 blowing Methods 0.000 claims description 9
- 239000002245 particle Substances 0.000 claims description 9
- 239000002817 coal dust Substances 0.000 claims description 7
- 230000001105 regulatory effect Effects 0.000 claims description 4
- 238000000926 separation method Methods 0.000 claims description 4
- 239000007787 solid Substances 0.000 claims description 4
- 238000002156 mixing Methods 0.000 claims description 3
- 238000009423 ventilation Methods 0.000 claims description 3
- 238000003801 milling Methods 0.000 claims description 2
- 238000012216 screening Methods 0.000 claims 1
- 238000004880 explosion Methods 0.000 abstract description 10
- 238000002360 preparation method Methods 0.000 abstract description 10
- 239000002802 bituminous coal Substances 0.000 abstract description 9
- 230000004044 response Effects 0.000 abstract description 9
- 238000002485 combustion reaction Methods 0.000 abstract description 5
- 239000000463 material Substances 0.000 abstract description 3
- 238000003860 storage Methods 0.000 abstract description 3
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- RHZUVFJBSILHOK-UHFFFAOYSA-N anthracen-1-ylmethanolate Chemical compound C1=CC=C2C=C3C(C[O-])=CC=CC3=CC2=C1 RHZUVFJBSILHOK-UHFFFAOYSA-N 0.000 description 4
- 239000003830 anthracite Substances 0.000 description 4
- 239000003077 lignite Substances 0.000 description 4
- 230000000630 rising effect Effects 0.000 description 3
- 238000010276 construction Methods 0.000 description 2
- 230000003111 delayed effect Effects 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 231100000206 health hazard Toxicity 0.000 description 2
- 238000007689 inspection Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
Classifications
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- 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
- F23C5/00—Disposition of burners with respect to the combustion chamber or to one another; Mounting of burners in combustion apparatus
- F23C5/08—Disposition of burners
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C17/00—Disintegrating by tumbling mills, i.e. mills having a container charged with the material to be disintegrated with or without special disintegrating members such as pebbles or balls
- B02C17/10—Disintegrating by tumbling mills, i.e. mills having a container charged with the material to be disintegrated with or without special disintegrating members such as pebbles or balls with one or a few disintegrating members arranged in the container
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23K—FEEDING FUEL TO COMBUSTION APPARATUS
- F23K3/00—Feeding or distributing of lump or pulverulent fuel to combustion apparatus
- F23K3/02—Pneumatic feeding arrangements, i.e. by air blast
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B17/00—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement
- F26B17/10—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed by fluid currents, e.g. issuing from a nozzle, e.g. pneumatic, flash, vortex or entrainment dryers
- F26B17/101—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed by fluid currents, e.g. issuing from a nozzle, e.g. pneumatic, flash, vortex or entrainment dryers the drying enclosure having the shape of one or a plurality of shafts or ducts, e.g. with substantially straight and vertical axis
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
- F26B21/14—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects using gases or vapours other than air or steam, e.g. inert gases
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B25/00—Details of general application not covered by group F26B21/00 or F26B23/00
- F26B25/001—Handling, e.g. loading or unloading arrangements
- F26B25/002—Handling, e.g. loading or unloading arrangements for bulk goods
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B3/00—Drying solid materials or objects by processes involving the application of heat
- F26B3/02—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air
- F26B3/10—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air the gas or vapour carrying the materials or objects to be dried with it
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Life Sciences & Earth Sciences (AREA)
- Microbiology (AREA)
- Food Science & Technology (AREA)
Abstract
The invention relates to a powder preparation system and a method of a steel ball mill for drying smoke of an intermediate bin type hot furnace, wherein the system structure comprises a raw coal bin, a coal feeder, a drying pipe, a steel ball mill, a coarse powder separator, a fine powder separator and a powder bin which are sequentially connected; the output end of the powder bin is connected to the boiler through a powder feeder and a wind powder mixer; the flue gas output end of the boiler is sequentially provided with an air preheater, a dust remover, an induced draft fan and a chimney; and pipelines are branched at the smoke output end of the boiler and the output end of the induced draft fan and are connected to the drying pipes. The scheme adopts an intermediate bin type system, obviously reduces the minimum powder supply amount, solves the problem of slow powder supply response rate caused by powder preparation delay, and is beneficial to low-load stable combustion of the boiler; meanwhile, the steel ball milling drying medium adopts hot flue gas as a main material, and is subjected to temperature adjustment by cold flue gas, so that the oxygen content of the drying medium is low, the inerting atmosphere is ensured in the whole process of grinding, drying and coal powder storage, and the problem of high bituminous coal explosion risk is fundamentally avoided.
Description
Technical Field
The invention belongs to the technical field of coal-fired power generation, and particularly relates to a system and a method for milling powder by using a steel ball mill through drying smoke in a hot furnace in an intermediate storage bin.
Background
The existing coal-fired generating unit powder production system mainly has four forms: 1. the medium-speed mill direct-fired pulverizing system is suitable for bituminous coal and lignite, is the main flow configuration of the current thermal power unit, and accounts for more than 80%; 2. the double-inlet double-tapping ball milling direct-blowing pulverizing system is suitable for anthracite (and lean coal) and overcomes the defect that a medium-speed mill cannot grind hard coal; 3. the fan mill direct-blowing pulverizing system is suitable for high-moisture lignite, and solves the problem of insufficient drying output when the high-moisture lignite is ground at a medium speed; 4. the intermediate warehouse type pulverizing system for steel ball mill is mainly applied to small capacity units below 20 ten thousand in nineties and 2000 and is mainly used for combusting anthracite or lean coal.
Most of the pulverizing systems of the thermal power generating units in China are direct blowing systems, mainly adopt a medium-speed mill, and only aim at special coal types (anthracite with high hardness and lignite with high moisture), correspondingly replace the medium-speed mill by a steel ball mill or a fan mill, so that the applicability problem of the medium-speed mill is solved, and no exception is taken to adopt the direct blowing system. Bin-type pulverizing systems have been rarely adopted in large thermal power units in recent decades due to long process, multiple devices, high risk, high cost and the like.
In order to adapt to the construction of a novel power system taking new energy as a main body, a thermal power unit is required to flexibly and rapidly lift load, have a wider operation load range and even develop in the direction of day start and stop so as to adapt to the scheduling requirement of a power grid (the new energy can be completely generated, and a power gap is supplemented by thermal power). The gas turbine unit plays an important role because of the characteristics of quick start and stop, wide load range and quick load rising rate. The coal-fired generator set is required to be aligned to the combustion engine, and technical development is carried out in the direction of starting and stopping daily at a wider load and a faster speed, but the powder supply response speed of the direct-fired pulverizing system adopted at present is slower, so that the required requirement is difficult to achieve.
Disclosure of Invention
The technical problems to be solved by the invention are as follows: the intermediate storage type hot furnace smoke drying steel ball milling powder preparing system and method solves the problem of slow powder supply response rate caused by delayed powder preparation, meets the rapid increase of the rapid load increase on the powder demand, and avoids the bituminous coal explosion risk.
According to the technical scheme of the invention, the invention provides a powder grinding system for a steel ball for drying smoke in an intermediate bin type hot furnace, which comprises a raw coal bin, a coal feeder, a drying pipe, a steel ball mill, a coarse powder separator, a fine powder separator and a powder bin which are sequentially connected; the output end of the powder bin is connected to the boiler through a powder feeder and a wind powder mixer; the flue gas output end of the boiler is sequentially provided with an air preheater, a dust remover, an induced draft fan and a chimney; and pipelines are branched at the smoke output end of the boiler and the output end of the induced draft fan and are connected to the drying pipes.
Further, the output end of the wind-powder mixer is connected with a primary wind burner of the boiler.
Further, the air purifier also comprises an air feeder, wherein the output end of the air feeder is branched to form two pipelines, one pipeline is connected with the air-powder mixer after passing through the air preheater, and the other pipeline is directly connected with the air-powder mixer.
Further, on the pipeline between the air preheater and the wind-powder mixer, a pipeline is also branched and connected to the overgrate air burner of the boiler.
Further, the fine powder separator is connected with a tertiary air burner of the boiler through a ventilation air fan.
Further, the fine powder output end of the coarse powder separator is connected with the fine powder separator, and the coarse powder output end of the coarse powder separator is connected with the steel ball mill.
The invention also provides a method for grinding the powder by using the intermediate bin type hot furnace smoke drying steel balls, which adopts an intermediate bin type system structure with a powder bin, and controls the oxygen content of a drying medium and a conveying medium in the whole process from before coal enters the steel ball mill to after coal powder enters the powder bin, so as to form an inerting atmosphere.
Further, the drying medium is formed by mixing hot flue gas and cold flue gas outside the flue gas output end of the boiler.
Further, the oxygen content of the drying medium is not more than 10%.
Further, the method is implemented by adopting the intermediate bin type hot smoke drying steel ball grinding powder system, and comprises the following steps:
coal is sent into steel ball mill from raw coal bin after passing through coal feeder and drying pipe, and is ground into coal powder;
hot flue gas pumped from a flue gas output end of the boiler in front of the air preheater is adopted, meanwhile, cold flue gas at an output end of the induced draft fan is mixed for temperature adjustment, the mixed flue gas is taken as a drying medium to enter a drying pipe for drying coal, and then the flue gas continuously enters a steel ball mill and is taken as a conveying medium for blowing out coal dust;
the blown coal powder flows through a coarse powder separator to screen out particles, the coal powder with the overlarge particle size returns into a steel ball mill to continue grinding, the coal powder with the qualified particle size enters a fine powder separator to carry out gas-solid separation, the separated coal powder enters a powder bin, and the separated exhaust gas is pressurized by an exhaust gas fan and sent to a tertiary air burner of a boiler;
the pulverized coal is sent into an air-powder mixer from a powder bin through a powder feeder, secondary hot air conveyed by a part of air feeder after passing through an air preheater is mixed with secondary cold air of the air feeder for temperature adjustment, and then flows through the air-powder mixer, and the pulverized coal sent to the air-powder mixer by the powder feeder is blown into a primary air burner of a boiler.
Compared with the prior art, the invention has the main beneficial technical effects that:
1. according to the intermediate bin type hot furnace smoke drying steel ball milling powder preparing system and method, the intermediate bin type hot furnace smoke drying steel ball milling powder preparing system is adopted, the minimum powder supplying amount is obviously reduced, the problem of slow powder supplying response rate caused by powder preparing delay is solved, compared with a direct blowing type hot furnace smoke drying steel ball milling powder preparing system, the low-load powder supplying amount can be reduced by 75%, and the constraint influence of the powder preparing delay on the unit load increasing rate is reduced to 0; the powder supply amount and the air distribution amount entering the primary air burner can be respectively and independently set, so that the air-coal ratio of the boiler under low load is reduced, and the stable combustion of the boiler under low load is facilitated.
2. The coal mill drying medium adopts hot flue gas as main material, and is subjected to temperature regulation by cold flue gas, the oxygen content of the drying medium is not more than 10%, the inerting atmosphere is ensured in the whole process of grinding, drying and coal powder storage, and the problem of high bituminous coal explosion risk is fundamentally avoided.
3. The drying medium is conveyed and the exhaust gas is pressurized by adopting a rear-mounted scheme of a fan, and after the exhaust gas fan is arranged on the fine powder separator, negative pressure powder preparation is realized, the An Jian ring level of a coal powder preparation workshop is improved, and occupational health hazard to power plant operation and inspection personnel is reduced.
4. The powder feeding link from the outlet of the powder bin to the primary air burner adopts the hot air from the outlet of the air feeder, namely the secondary hot air for feeding powder, and the setting of the primary air blower is canceled.
Drawings
Fig. 1 is a schematic structural view of a conventional steel ball mill intermediate bin type pulverizing system.
Fig. 2 is a schematic diagram of the system architecture of the present invention.
Reference numerals in the drawings illustrate:
1. raw coal bin;
2. a coal feeder;
3. a drying tube;
4. ball milling of steel;
5. a coarse powder separator;
6. a fines separator;
7. a powder bin;
8. a powder feeder;
9. a wind-powder mixer;
10. a boiler;
11. a primary air burner;
12. a secondary air burner;
13. a tertiary air burner;
14. an air preheater;
15. a dust remover;
16. an induced draft fan;
17. a chimney;
18. a blower;
19. a exhaust fan.
Detailed Description
The invention provides a powder preparation system and a method for a steel ball mill by drying smoke in an intermediate bin type hot furnace, which solve the problem of slow powder supply response rate caused by delayed powder preparation, meet the rapid increase of the load on the powder demand, and avoid the explosion risk of bituminous coal.
The main idea of the present invention is as follows. The angle of standing on the combustion side of the boiler needs to realize wider load and faster unit load rising rate, namely the lowest load level of the boiler needs to be suppressed as much as possible, so that the powder supply quantity with low load is realized as much as possible, the powder supply response speed is improved, and the rapid increase of the load rising speed to the powder demand is met. The hysteresis of the pulverizing system (the process of grinding raw coal into pulverized coal with acceptable fineness) cannot be avoided, and in order to realize the rapid response of powder supply, the best method is to prepare the pulverized coal in advance for later use, namely an intermediate bin type system is adopted.
A traditional steel ball mill warehouse-type pulverizing system is shown in figure 1, and has the main structure and working process that coal is fed into a steel ball mill (steel ball mill for short) from a raw coal warehouse through a coal feeder and a drying pipe (mill inlet drying section) and is ground into coal powder with qualified fineness. The primary air flows through an air preheater to become primary hot air, and the primary hot air is mixed with part of primary cold air to be used as a drying medium to enter a drying pipe, so that raw coal is dried, and then enters a steel ball mill. Blowing out pulverized coal in a mill, flowing through a coarse powder separator, separating out pulverized coal with unqualified fineness, returning the pulverized coal into a steel ball mill, carrying the pulverized coal with qualified fineness into a fine powder separator by primary air, carrying out gas-solid separation, separating out pulverized coal, entering a powder bin, and entering a tertiary air burner of a boiler after the pulverized coal is boosted by a powder discharge fan from the top exhaust gas (about 5-10% of pulverized coal) of the fine powder separator. The powder feeding adopts hot air powder feeding, part of secondary hot air is led to be mixed with a small amount of secondary cold air for temperature adjustment, and then flows through an air-powder mixer, and the pulverized coal fed by a powder feeder at the lower part of a powder bin is blown into a primary air burner of a boiler.
The system is a powder preparation system configuration scheme which is applied more when the unit capacity is below 300MW in twenty years ago in China, and can solve the problems of low powder supply response speed and minimum powder supply amount, but the application conditions are mainly limited to anthracite or lean coal, and the volatile matters are lower, so that the explosion risk is still lower under the condition of higher heat generated in the steel ball grinding process. And for bituminous coal with high volatile matters, no application case exists, and the risk is high. Therefore, in order to be transplanted to the bituminous coal, the explosion protection problem needs to be considered. In this way, the scheme of the invention adopts the mode that the oxygen content of the drying and conveying medium is controlled in the whole process from the grinding advance to the powder discharge so as to form an inerting atmosphere, thereby fundamentally solving the problem of explosion prevention.
Referring to fig. 2, the intermediate bin type hot flue gas drying steel ball grinding powder making system mainly comprises a raw coal bin 1, a coal feeder 2, a drying pipe 3, a steel ball mill 4, a coarse powder separator 5, a fine powder separator 6 and a powder bin 7 which are sequentially connected. The output of the powder bin 7 is connected to a boiler 10 through a powder feeder 8 and a wind powder mixer 9. The flue gas output end of the boiler 10 is provided with an air preheater 14, a dust remover 15, an induced draft fan 16 and a chimney 17 in sequence. The flue gas output end (specifically, for example, a flue in front of the air preheater 14) of the boiler 10 and the output end (specifically, for example, a flue between the induced draft fan 16 and the chimney 17) of the induced draft fan 16 are branched and are both connected to the drying medium input end of the drying pipe 3, so that the hot flue gas and the cold flue gas with very low oxygen content at the two positions are respectively introduced as the drying medium of coal and the conveying medium of the subsequent pulverized coal to form inert atmosphere, thereby avoiding explosion. Preferably, the drying medium input end of the drying pipe 3 is an inlet pipeline, the hot flue gas and the cold flue gas pipeline are converged and regulated at the inlet pipeline, and a temperature measuring device and the like can be arranged on the inlet pipeline, so that the flue gas temperature is basically uniform and meets the requirements, and then the flue gas enters the drying pipe 3.
More specifically, the boiler 10 has a primary air burner 11, a secondary air burner 12, and a tertiary air burner 13 at its input. The output end of the wind-powder mixer 9 is connected with a primary wind burner 11 of a boiler 10. The air supply device also comprises an air blower 18, wherein the output end of the air blower 18 is branched to form two pipelines, one pipeline is connected with the hot air input end of the air-powder mixer 9 after passing through the air preheater 14, the other pipeline is directly connected with the hot air input end of the air-powder mixer 9, and the two pipelines are used for regulating temperature to form hot air used in the powder supply process; before the pulverized coal enters the burner of the boiler 10 from the air-powder mixer 9, the temperature (ignition energy) of the pulverized coal is insufficient, so that the oxygen contained in the hot air for feeding the pulverized coal is not easy to explode. Preferably, the hot air input end of the air-powder mixer 9 is an inlet pipeline, the pipeline of the hot air heated by the air preheater 14 and the pipeline of the cold air not heated by the air preheater 14 are converged and temperature-regulated at the one inlet pipeline, and a temperature measuring device and the like can be arranged on the pipeline, so that the temperature of the air (hot air) is basically uniform and meets the requirement, and then the air (hot air) enters the air-powder mixer 9.
In the line between the air preheater 14 and the air-powder mixer 9, there is also branched a line connected to the overgrate air burner 12 of the boiler 10, so as to supply the boiler with the required oxygen. The fine powder output end of the coarse powder separator 5 is connected with the fine powder separator 6, and the coarse powder output end of the coarse powder separator 5 is connected with the steel ball mill 4, so that coarse powder and fine powder are screened and continuously ground. The gas output end of the fine powder separator 6 is connected with a tertiary air burner 13 of the boiler 10 through a ventilation air fan 19, so as to realize the function of recycling boiler flue gas.
Based on the above inventive concept and system structure, the invention provides a method for grinding powder by using an intermediate bin type hot furnace smoke drying steel ball, which adopts an intermediate bin type system structure with a powder bin 7, and controls the oxygen content of a drying medium and a conveying medium in the whole process from coal entering the steel ball mill 4 to coal dust entering the powder bin 7 to form an inerting atmosphere, thereby realizing reliable explosion protection. Preferably, the drying medium is formed by mixing hot flue gas and cold flue gas outside the flue gas output end of the boiler 10. The oxygen content of the drying medium is preferably not more than 10%.
Further specifically, taking the preferred embodiment shown in fig. 2 as an example, the method for grinding the steel balls by using the intermediate bin type hot smoke drying steel balls mainly comprises the following steps:
coal is fed into a steel ball mill 4 from a raw coal bin 1 through a coal feeder 2 and a drying pipe 3 (an inlet drying section of the steel ball mill 4), and is ground into coal dust.
The process of drying coal adopts hot flue gas extracted from a flue gas output end (flue) of the boiler 10 in front of the air preheater 14, and simultaneously mixes a small amount of cold flue gas at the output end of the induced draft fan 16 for temperature adjustment, and the mixed flue gas enters the drying pipe 3 as a drying medium to dry raw coal.
The flue gas (carrying a small amount of steam evaporated from the raw coal) then continues to enter the steel ball mill 4 together with the coal as a conveying medium to blow out the pulverized coal milled in the steel ball mill 4.
The blown coal powder flows through the coarse powder separator 5 to screen out particles, the coal powder with overlarge particle size returns into the steel ball mill 4 to continue grinding, and the coal powder with qualified particle size enters the fine powder separator 6 to carry out gas-solid separation.
The separated coal powder enters the powder bin 7, and the separated exhaust gas is pressurized by an exhaust gas fan 19 and sent to a tertiary air burner 13 of the boiler 10. Wherein the exhaust gas comprises a drying medium (namely boiler flue gas), steam evaporated from coal and 5-10% of coal dust.
The powder feeding adopts hot air powder feeding, specifically, pulverized coal is fed into an air powder mixer 9 from a powder bin 7 through a powder feeder 8, secondary hot air conveyed by a part of air blowers 18 after passing through an air preheater 14 is mixed with secondary cold air of a small amount of air blowers 18 to adjust temperature, and then flows through the air powder mixer 9, and the pulverized coal fed out from the powder feeder 8 to the air powder mixer 9 is blown into a primary air burner 11 of a boiler 10.
It should be noted that the above system and method of the present invention only illustrate major improvements and relevant parts, and other parts not described in detail, for example, a pipeline for communicating each part in the system is provided with a valve control system according to need, and then, the temperature and flow rate control in the method are performed according to need by adopting the prior art scheme; and a fan or an air pump can be additionally arranged in a specific pipeline according to the requirement so as to further control the flue gas/air flow and the like.
In summary, the main characteristics, advantages and innovations of the invention are as follows:
1. according to the intermediate bin type hot furnace smoke drying steel ball milling powder preparing system and method, the intermediate bin type hot furnace smoke drying steel ball milling powder preparing system is adopted, the minimum powder supplying amount is obviously reduced, the problem of slow powder supplying response rate caused by powder preparing delay is solved, compared with a direct blowing type hot furnace smoke drying steel ball milling powder preparing system, the low-load powder supplying amount can be reduced by 75%, and the constraint influence of the powder preparing delay on the unit load increasing rate is reduced to 0; the powder supply amount and the air distribution amount entering the primary air burner can be respectively and independently set, so that the air-coal ratio of the boiler under low load is reduced, and the stable combustion of the boiler under low load is facilitated.
2. The coal mill drying medium adopts hot flue gas as a main material, and is subjected to temperature regulation by cold flue gas, the oxygen content of the drying medium is not more than 10%, and the coal mill is milled, dried and a coal powder storage bin, so that an inerting atmosphere is ensured in the whole process, and the problem of high bituminous coal explosion risk is fundamentally avoided.
3. The drying medium is conveyed and the exhaust gas is pressurized by adopting a rear-mounted scheme of a fan, and after the exhaust gas fan is arranged on the fine powder separator, negative pressure powder preparation is realized, the An Jian ring level of a coal powder preparation workshop is improved, and occupational health hazard to power plant operation and inspection personnel is reduced.
4. Because the coal powder content in the exhaust gas of the pulverizing is relatively large and the oxygen content is extremely low, the exhaust gas cannot be used for delivering the pulverized coal at the moment.
5. The powder feeding link from the outlet of the powder bin to the primary air burner adopts the hot air from the outlet of the air feeder, namely the secondary hot air for feeding powder, and the setting of the primary air blower is canceled.
6. The adopted system structure is relatively mature, and only the characteristic of high volatile matter of the bituminous coal is aimed at, the drying medium is changed into the mixed drying medium of cold and hot smoke from the mixed gas of cold and hot air, the design and construction of the system are convenient, and a new integral system and components are not required to be designed.
Claims (10)
1. The intermediate storage bin type hot furnace smoke drying steel ball milling system is characterized by comprising a raw coal bin (1), a coal feeder (2), a drying pipe (3), a steel ball mill (4), a coarse powder separator (5), a fine powder separator (6) and a powder bin (7) which are sequentially connected; the output end of the powder bin (7) is connected to a boiler (10) through a powder feeder (8) and a wind powder mixer (9); the flue gas output end of the boiler (10) is sequentially provided with an air preheater (14), a dust remover (15), an induced draft fan (16) and a chimney (17); and a pipeline is branched at the smoke output end of the boiler (10) and the output end of the induced draft fan (16) and is connected to the drying pipe (3).
2. An intermediate bin type hot flue gas drying steel ball milling system according to claim 1, characterized in that the output end of the wind-powder mixer (9) is connected with a primary wind burner (11) of the boiler (10).
3. The intermediate bin type hot flue gas drying steel ball grinding powder system according to claim 2, further comprising a blower (18), wherein the output end of the blower (18) is branched into two pipelines, one pipeline is connected with the wind powder mixer (9) after passing through the air preheater (14), and the other pipeline is directly connected with the wind powder mixer (9).
4. An intermediate bin type hot flue gas drying steel ball milling system as claimed in claim 3, characterized in that a secondary air burner (12) connected to said boiler (10) is branched off in the line between said air preheater (14) and said air-powder mixer (9).
5. An intermediate bin type hot flue gas drying steel ball milling system as claimed in claim 4, wherein the fines separator (6) is connected to a tertiary air burner (13) of the boiler (10) by a ventilation air fan (19).
6. An intermediate bin type hot flue gas drying steel ball mill pulverizing system according to claim 5, characterized in that the fine powder output end of the coarse powder separator (5) is connected with the fine powder separator (6), and the coarse powder output end of the coarse powder separator (5) is connected with the steel ball mill (4).
7. The method for grinding the powder by using the steel balls through drying the smoke in the intermediate bin type hot furnace is characterized in that an intermediate bin type system structure with a powder bin (7) is adopted, and the oxygen content of a drying medium and an oxygen content of a conveying medium are controlled in the whole process from the time when coal enters the steel ball mill (4) to the time when coal dust enters the powder bin (7), so that an inerting atmosphere is formed.
8. The method for grinding powder of steel balls by using the intermediate bin type hot flue gas drying process according to claim 7, wherein the drying medium is formed by mixing hot flue gas and cold flue gas outside a flue gas output end of a boiler (10).
9. The method for grinding steel balls into powder according to claim 7, wherein said drying medium has an oxygen content of not more than 10%.
10. The method for grinding and pulverizing the steel balls by using the intermediate warehouse type hot smoke drying steel ball as claimed in claim 7, which is implemented by using the intermediate warehouse type hot smoke drying steel ball grinding and pulverizing system as claimed in claim 6, and comprises the following steps:
coal is sent into the steel ball mill (4) from the raw coal bin (1) through the coal feeder (2) and the drying pipe (3) and is ground into coal dust;
hot flue gas extracted from a flue gas output end of the boiler (10) in front of the air preheater (14) is adopted, meanwhile cold flue gas at an output end of the induced draft fan (16) is mixed for temperature adjustment, the mixed flue gas is taken as a drying medium to enter the drying pipe (3) for drying coal, and then the flue gas continuously enters the steel ball mill (4) to be taken as a conveying medium for blowing coal dust;
the blown coal powder flows through the coarse powder separator (5) for particle screening, the coal powder with the overlarge particle size returns into the steel ball mill (4) for continuous milling, the coal powder with the qualified particle size enters the fine powder separator (6) for gas-solid separation, the separated coal powder enters the powder bin (7), and the separated exhaust gas is pressurized by the exhaust gas fan (19) and is sent to the tertiary air burner (13) of the boiler (10);
pulverized coal is fed into the air-powder mixer (9) from the powder bin (7) through the powder feeder (8), secondary hot air conveyed by the blower (18) after passing through the air preheater (14) is mixed with secondary cold air of the blower (18) to be temperature-regulated, and then flows through the air-powder mixer (9), and the pulverized coal fed from the powder feeder (8) to the air-powder mixer (9) is blown into the primary air burner (11) of the boiler (10).
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310477717.4A CN116817261A (en) | 2023-04-28 | 2023-04-28 | Intermediate storage bin type hot furnace smoke drying steel ball milling powder making system and method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310477717.4A CN116817261A (en) | 2023-04-28 | 2023-04-28 | Intermediate storage bin type hot furnace smoke drying steel ball milling powder making system and method |
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