CN114001558A - Flue gas waste heat reutilization process device - Google Patents
Flue gas waste heat reutilization process device Download PDFInfo
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- CN114001558A CN114001558A CN202111344703.2A CN202111344703A CN114001558A CN 114001558 A CN114001558 A CN 114001558A CN 202111344703 A CN202111344703 A CN 202111344703A CN 114001558 A CN114001558 A CN 114001558A
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- Prior art keywords
- flue gas
- primary
- outlet
- inlet
- preheater
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
- F27D17/004—Systems for reclaiming waste heat
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
- F23L15/00—Heating of air supplied for combustion
- F23L15/04—Arrangements of recuperators
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
- F27D17/008—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases cleaning gases
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
- F27D17/004—Systems for reclaiming waste heat
- F27D2017/006—Systems for reclaiming waste heat using a boiler
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E20/00—Combustion technologies with mitigation potential
- Y02E20/34—Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/25—Process efficiency
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Air Supply (AREA)
- Chimneys And Flues (AREA)
Abstract
The invention discloses a process unit for secondary utilization of flue gas waste heat, which sequentially comprises a coal-fired (coal-fired or oil-fired) boiler, a secondary preheater, a dust remover, a flue gas cooler, a desulfurizing tower and a flue gas discharge tower according to a flue gas flow. The primary preheater is provided with a heat exchange coil pipe and is used for primary heat exchange of air and flue gas, the waste heat utilization rate is high, the coal consumption is reduced, and the desulfurization effect is good.
Description
Technical Field
The invention relates to a flue gas waste heat recycling technology.
Background
The waste heat is energy which is not utilized in energy utilization equipment under certain economic and technical conditions, namely redundant and waste energy. The method comprises seven types of waste heat of high-temperature waste gas, waste heat of cooling medium, waste heat of waste steam and waste water, waste heat of high-temperature products and furnace slag, waste heat of chemical reaction, waste heat of combustible waste gas and waste material, and residual pressure of high-pressure fluid. According to investigation, the total waste heat resources of all industries account for 17% -67% of the total fuel consumption, and the recyclable waste heat resources account for 60% of the total waste heat resources.
The waste heat recycling is an important way for improving the economy and saving the fuel. The waste gas and waste heat utilization method commonly used by metallurgical enterprises comprises the steps of installing a heat exchanger, installing a waste heat boiler behind the heat exchanger, vaporizing and cooling a furnace bottom pipe, generating electricity (cogeneration), and refrigerating. The recovered heat is mainly used for preheating combustion air, preheating coal gas and producing steam. For the electric furnace, the electric energy consumption of the electric furnace can be reduced by preheating the scrap steel or feeding materials, and the smelting time is shortened; for a heating furnace, air, fuel or workpieces are preheated, and the waste heat of flue gas returns to the furnace, so that flame is stabilized, and the temperature of the fuel, the combustion efficiency and the thermal efficiency of the furnace are improved.
The reason for poor waste heat recovery of the industrial furnace kiln is that besides high exhaust gas temperature and small capacity of a heat exchanger, attention is paid to the fact that sensible heat of flue gas and hot air cannot be effectively stored, the flue gas is emitted from a hearth and is sucked into cold air, an underground flue leaks water and air, a bypass flue is short-circuited, and pipeline heat insulation is poor, so that the heat loss of the flue gas of most furnaces in front of a recovery device is up to 30-50%, and the sensible heat loss of return hot air is 20-33%.
Disclosure of Invention
The purpose of the invention is as follows:
the flue gas waste heat secondary utilization process device has the advantages of high waste heat recovery utilization rate and combination of heat convection, heat exchange and reaction heat.
The technical scheme is as follows:
the flue gas waste heat reutilization process device is sequentially provided with a coal-fired (coal-fired or oil-fired) boiler, a secondary preheater, a dust remover, a flue gas cooler, a desulfurizing tower and a flue gas discharge tower according to a flue gas flow.
The primary preheater is provided with a heat exchange coil and is used for the first heat exchange between air and flue gas; the heat exchange coil has a primary cold air (coolant) inlet and a primary hot air outlet, and a secondary hot flue gas inlet and a secondary cold flue gas outlet.
The secondary preheater is provided with a secondary air inlet positioned at the lower part and a secondary hot air outlet positioned at the upper part; and a primary hot flue gas inlet and a primary flue gas outlet are also arranged. The air and the flue gas are directly mixed in the coal-fired boiler, and most of the air and the flue gas enter an air inlet of the coal-fired boiler; a small amount flows out from the primary flue gas outlet.
The lower part of the coal-fired boiler is provided with an air inlet and a coal-fired inlet, and the upper part of the coal-fired boiler is provided with a cold water inlet and a steam outlet.
And a primary hot air outlet above the primary preheater of the primary preheater is communicated with a secondary air inlet below the secondary preheater, and a secondary hot air outlet of the secondary preheater is communicated with an air inlet of the coal-fired boiler.
A primary flue gas outlet of the secondary preheating tower is communicated with an inlet of a dust remover, an outlet of the dust remover is communicated with a flue gas cooler, and the flue gas cooling tower is provided with a secondary flue gas inlet; and a smoke liquid (mixture of liquid and gas) outlet is arranged at the bottom, a secondary smoke outlet on the side wall is communicated with a secondary hot smoke inlet, and a secondary cold smoke outlet is communicated with a tertiary smoke inlet. The flue gas after dust removal is not easy to pollute the heat exchange coil pipe, and the heat exchange efficiency is not greatly influenced.
The smoke liquid outlet of the smoke cooling tower is communicated with the inlet of the desulfurizing tower, and the desulfurizing tower is provided with a tail gas outlet which is communicated with the discharging tower.
The process flow comprises the following steps:
cold air passes through the primary preheater, is preheated for the first time, then enters the secondary preheater, is preheated again, becomes hot air, enters the coal-fired boiler, improves the furnace temperature, enables the combustion efficiency of coal to be higher, and makes full use of the waste heat in the flue gas.
The high-temperature flue gas that the boiler came out is by the first cooling in secondary preheater, and the dust is got rid of by the dust remover after the flue gas comes out, becomes the dust removal flue gas, gets into flue gas cooling tower after that, and the heat exchange is carried out with the heat exchange coil pipe in the primary preheater to the dust removal flue gas in the flue gas cooling tower, has further reduced the temperature of dust removal flue gas. The returned dedusting flue gas contains tail gas and condensate, the tail gas and the condensate flow out from the bottom of the flue gas cooling tower together, the flue gas enters a desulfurizing tower for desulfurization, and the final tail gas enters an exhaust tower for emptying.
The secondary preheater is preferably preset with a vanadium pentoxide catalyst and is provided with a temperature sensor, when the temperature in the secondary preheater is 400-620 ℃ (at the temperature, sulfur dioxide is catalytically oxidized into sulfur trioxide by oxygen in the secondarily preheated hot air), the primary flue gas outlet is opened, so that the gas entering the flue gas cooling tower is cooled, and the sulfur trioxide becomes liquid and flows out from the bottom together with the gas.
Has the advantages that:
the invention utilizes waste heat twice, has high utilization rate of waste heat and reduces the consumption of fire coal. Sulfur dioxide in the flue gas is basically converted into sulfur trioxide and is recovered, the desulfurization effect is good, and basically no sulfur is discharged. In the primary heat exchanger, the flue gas is directly mixed with air, dust removal is not needed, and the flue gas directly enters the coal-fired boiler, so that coal dust is fully combusted, and the waste of coal resources is reduced. The dust remover is arranged in front of the secondary heat exchanger to remove dust, avoid deposition in the heat exchanger to reduce heat exchange effect and reduce dust emission to the atmosphere.
Drawings
FIG. 1 is a schematic diagram of an apparatus and process of the present invention;
in the figure, 1-boiler; 2, a secondary preheater; 3, an electric dust remover; 4-a flue gas cooler; 5-a desulfurizing tower; 6-a discharge column; 7-primary preheater; 21-primary hot flue gas inlet; 22-primary flue gas outlet; 23-a secondary air inlet; 24-hot air outlet; 41-secondary flue gas inlet; 42-secondary flue gas outlet; 43-three flue gas inlets; 44-tobacco juice outlet 71-secondary hot flue gas inlet; 72-secondary cold flue gas outlet; 73-primary cold air inlet; 74-primary hot air outlet.
Detailed Description
The process device for secondary utilization of flue gas waste heat shown in fig. 1 sequentially comprises a coal-fired boiler, a dust remover, a flue gas cooler, a desulfurizing tower and a flue gas discharge tower according to a flue gas flow, wherein a secondary preheater is arranged between the coal-fired boiler and the dust remover, and is provided with a secondary air inlet positioned at the lower part and a secondary hot air outlet positioned at the upper part; a primary hot flue gas inlet for boiler flue gas to enter and a primary flue gas outlet for flue gas to flow out are arranged; in the secondary preheater, the secondary air is directly mixed with the primary flue gas to form hot air, and most of the hot air enters an air inlet of the coal-fired boiler; a small amount flows out from the primary flue gas outlet.
The primary preheater is provided with a heat exchange coil and is used for the first heat exchange between air and flue gas; the heat exchange coil is provided with a primary cold air inlet, a primary hot air outlet, a secondary hot flue gas inlet and a secondary cold flue gas outlet; the primary hot air outlet above the primary preheater is communicated with the secondary air inlet below the secondary preheater.
The primary flue gas outlet is communicated with the inlet of the dust remover, and the outlet of the dust remover is communicated with the flue gas cooler. The flue gas cooling tower is provided with a secondary flue gas inlet, a flue gas liquid outlet is arranged at the bottom of the flue gas cooling tower, the secondary flue gas outlet on the side wall is communicated with the secondary hot flue gas inlet, and the secondary cold flue gas outlet is communicated with the tertiary flue gas inlet.
Claims (3)
1. The utility model provides a flue gas waste heat reutilization process units, according to the flue gas flow, has coal fired boiler, dust remover, flue gas cooler, desulfurizing tower, flue gas emission tower in proper order, its characterized in that: a secondary preheater is arranged between the coal-fired boiler and the dust remover, and is provided with a secondary air inlet positioned at the lower part and a secondary hot air outlet positioned at the upper part; a primary hot flue gas inlet and a primary flue gas outlet are also arranged; directly mixing air and flue gas in a secondary preheater, and enabling most of the air to enter an air inlet of the coal-fired boiler; a small amount flows out from the primary flue gas outlet.
2. The secondary utilization process unit for flue gas waste heat according to claim 1, characterized in that: the primary preheater is provided with a heat exchange coil and is used for the first heat exchange between air and flue gas; the heat exchange coil is provided with a primary cold air inlet, a primary hot air outlet, a secondary hot flue gas inlet and a secondary cold flue gas outlet; the primary hot air outlet of the primary preheater is communicated with the secondary air inlet below the secondary preheater.
3. The secondary utilization process unit for flue gas waste heat according to claim 1 or 2, characterized in that: a primary flue gas outlet of the secondary preheating tower is communicated with an inlet of a dust remover, an outlet of the dust remover is communicated with a flue gas cooler, and the flue gas cooling tower is provided with a secondary flue gas inlet; the bottom is provided with a tobacco juice outlet; the secondary flue gas outlet of the side wall is communicated with the secondary hot flue gas inlet, and the secondary cold flue gas outlet is communicated with the tertiary flue gas inlet.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111344703.2A CN114001558A (en) | 2021-11-15 | 2021-11-15 | Flue gas waste heat reutilization process device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111344703.2A CN114001558A (en) | 2021-11-15 | 2021-11-15 | Flue gas waste heat reutilization process device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114001558A true CN114001558A (en) | 2022-02-01 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111344703.2A Pending CN114001558A (en) | 2021-11-15 | 2021-11-15 | Flue gas waste heat reutilization process device |
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| CN (1) | CN114001558A (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1227846A (en) * | 1967-04-05 | 1971-04-07 | ||
| CN201636884U (en) * | 2009-09-27 | 2010-11-17 | 西安交通大学 | Deep cooling and waste heat recovery device for boiler smoke gas |
| CN103968401A (en) * | 2014-04-18 | 2014-08-06 | 华北电力大学 | Dedusting, desulfuration and waste-heat utilization integrated system with low PM2.5 emission |
| CN104197343A (en) * | 2014-08-29 | 2014-12-10 | 华北电力大学 | Oxygen-enriched combustion recycle flue gas catalytic desulfurization system and method |
| CN104534450A (en) * | 2014-08-28 | 2015-04-22 | 国电龙源电力技术工程有限责任公司 | Smoke waste heat comprehensive utilization device for thermal power plant |
| US20160169510A1 (en) * | 2014-12-16 | 2016-06-16 | Great River Energy | Method and system for reheating flue gas using waste heat to maintain dry chimney stack operation |
-
2021
- 2021-11-15 CN CN202111344703.2A patent/CN114001558A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1227846A (en) * | 1967-04-05 | 1971-04-07 | ||
| CN201636884U (en) * | 2009-09-27 | 2010-11-17 | 西安交通大学 | Deep cooling and waste heat recovery device for boiler smoke gas |
| CN103968401A (en) * | 2014-04-18 | 2014-08-06 | 华北电力大学 | Dedusting, desulfuration and waste-heat utilization integrated system with low PM2.5 emission |
| CN104534450A (en) * | 2014-08-28 | 2015-04-22 | 国电龙源电力技术工程有限责任公司 | Smoke waste heat comprehensive utilization device for thermal power plant |
| CN104197343A (en) * | 2014-08-29 | 2014-12-10 | 华北电力大学 | Oxygen-enriched combustion recycle flue gas catalytic desulfurization system and method |
| US20160169510A1 (en) * | 2014-12-16 | 2016-06-16 | Great River Energy | Method and system for reheating flue gas using waste heat to maintain dry chimney stack operation |
Non-Patent Citations (1)
| Title |
|---|
| 林文孚主编: "《单元机组热力设备运行》", 水利水电出版社, pages: 33 * |
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