CN110805923A - Steam air preheater system based on energy cascade utilization - Google Patents
Steam air preheater system based on energy cascade utilization Download PDFInfo
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- CN110805923A CN110805923A CN201911245840.3A CN201911245840A CN110805923A CN 110805923 A CN110805923 A CN 110805923A CN 201911245840 A CN201911245840 A CN 201911245840A CN 110805923 A CN110805923 A CN 110805923A
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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
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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
Abstract
The invention discloses a steam air preheater system based on energy gradient utilization, which comprises 3 steam heating stages and 6 hydrophobic heating stages; the 3 steam heating stages are respectively a low-pressure steam heating stage, a medium-pressure steam heating stage and a high-pressure steam heating stage along the direction of an air inlet; the 6 hydrophobic heating stages comprise 3 hydrophobic low-temperature heating stages, 2 hydrophobic medium-temperature heating stages and 1 hydrophobic high-temperature heating stage. According to the invention, 9 heating stages are adopted to heat air according to different heat source qualities, so that the gradient utilization of energy is realized, and the utilization efficiency of energy is improved; after the heat energy of each stage of steam is utilized in a gradient manner, the heat load impact of drainage on the deaerator is reduced, the self-boiling of the deaerator is effectively prevented, and the operation risk of the boiler is reduced; the cold air is heated by adopting multi-stage and low-temperature rise, thereby effectively relieving the influence of load fluctuation on the air temperature and ensuring the stable operation of the incineration system.
Description
Technical Field
The invention relates to the technical field of waste incineration power generation, in particular to a steam air preheater system.
Background
The air preheater is an air heating device which utilizes waste heat to improve the temperature of air entering a hearth so as to facilitate combustion. The method has the main functions of improving the theoretical combustion temperature of the fuel, ensuring the furnace temperature, improving the combustion efficiency and the like. Because the boiler flue gas of the waste incineration power plant contains more acid gas and is very easy to cause low-temperature corrosion at low temperature, a steam air preheater for heating air by steam is generally adopted. The steam air preheater system has great influence on stable combustion of garbage, stability of a thermodynamic system and heat efficiency of a whole plant.
The conventional steam air preheater in a waste incineration power plant is 2-stage heating: the first stage is a low-pressure heating section, and the heat source is a first-stage extraction steam of a steam turbine; the second stage is a high-pressure heating section, and the heat source is superheated main steam or saturated steam of a steam drum. Conventional steam air preheaters suffer from the following disadvantages: 1) two-stage heating is adopted, so that energy is not fully utilized, the heat efficiency is low, and energy is wasted; 2) when the load of the boiler changes, the air temperature of each heating section often cannot reach the design temperature; 3) the heat of the drainage is not fully utilized, and a large amount of heat carried in the drainage directly enters the deaerator after vaporization to cause the deaerator to boil by itself, so that the deaerating effect is reduced, and the safe operation of the boiler is influenced.
Disclosure of Invention
The invention aims to provide an efficient and stable steam air preheater system based on energy cascade utilization.
The specific technical scheme of the invention is as follows:
a steam air preheater system based on energy cascade utilization comprises 3 steam heating stages and 6 hydrophobic heating stages. The 3 steam heating stages are respectively a low-pressure steam heating stage, a medium-pressure steam heating stage and a high-pressure steam heating stage along the direction of an air inlet, and the steam source of each heating stage is respectively from the secondary steam extraction of a steam turbine, the primary steam extraction of the steam turbine and the saturated steam of a boiler drum; the 6 hydrophobic heating stages comprise 3 hydrophobic low-temperature heating stages, 2 hydrophobic medium-temperature heating stages and 1 hydrophobic high-temperature heating stage, the low-pressure hydrophobic low-temperature heating stage, the medium-pressure hydrophobic low-temperature heating stage, the high-pressure hydrophobic low-temperature heating stage, the medium-pressure hydrophobic medium-temperature heating stage, the high-pressure hydrophobic medium-temperature heating stage and the high-pressure hydrophobic high-temperature heating stage are respectively arranged along the direction of an air inlet, and the heat source of each hydrophobic heating stage is from the hydrophobic of the steam heating stage with the corresponding pressure. The arrangement relation of each steam heating stage and each hydrophobic heating stage along the direction of the air inlet is as follows: 1 low-pressure steam heating stage is arranged behind 3 hydrophobic low-temperature heating stages, 1 medium-pressure steam heating stage is arranged behind 2 hydrophobic medium-temperature heating stages, and 1 high-pressure steam heating stage is arranged behind 1 hydrophobic high-temperature heating stage. The heat exchange process of each stage of steam is as follows: saturated steam from a boiler drum is condensed into saturated drain after being subjected to heat release in a high-pressure steam heating stage, the saturated drain enters a high-pressure drain high-temperature heating stage for further heat release to form super-cooled drain, and the super-cooled drain enters a deaerator after being subjected to two-stage heat release in a high-pressure drain medium-temperature heating stage and a high-pressure drain low-temperature heating stage; superheated steam from the first-stage steam extraction of the steam turbine is condensed into saturated drain after being subjected to heat release by a medium-pressure steam heating stage, the saturated drain enters a medium-pressure drain medium-temperature heating stage for further heat release to form supercooled drain, and the supercooled drain enters a deaerator after being subjected to heat release by a medium-pressure drain low-temperature heating stage; superheated steam from the secondary steam extraction of the steam turbine is condensed into saturated drain after being subjected to heat release by the low-pressure steam heating stage, and the saturated drain enters the low-pressure drain low-temperature heating stage to further release heat to form super-cooled drain and enters the deaerator.
The invention has the beneficial effects that: the system is safe, reliable, stable and efficient, and adopts 9 heating stages to heat air according to different heat source qualities, so that the gradient utilization of energy is realized, the utilization efficiency of the energy is improved, and the purposes of energy conservation and consumption reduction are achieved; the heat energy of each stage of steam is utilized in a gradient manner, the heat quantity of the tail end drain is greatly reduced, the heat load impact of the drain on the deaerator is reduced, the self-boiling of the deaerator is effectively prevented, and the operation risk of the boiler is reduced; the cold air is heated by adopting multi-stage and low-temperature rise, thereby effectively relieving the influence of load fluctuation on the air temperature and ensuring the stable operation of the incineration system.
Drawings
FIG. 1 is a schematic diagram of a steam air preheater system based on energy cascade utilization according to the present invention.
FIG. 2 is a schematic diagram of the apparatus of the system of the present invention.
In the figure: 1-low pressure hydrophobic low temperature heating stage, 2-medium pressure hydrophobic low temperature heating stage, 3-high pressure hydrophobic low temperature heating stage, 4-low pressure steam heating stage, 5-medium pressure hydrophobic medium temperature heating stage, 6-high pressure hydrophobic medium temperature heating stage, 7-medium pressure steam heating stage, 8-high pressure hydrophobic high temperature heating stage, 9-high pressure steam heating stage.
Detailed Description
The steam air preheater system based on energy cascade utilization as shown in the attached figure 1 comprises a low-pressure hydrophobic low-temperature heating stage 1, a medium-pressure hydrophobic low-temperature heating stage 2, a high-pressure hydrophobic low-temperature heating stage 3, a low-pressure steam heating stage 4, a medium-pressure hydrophobic medium-temperature heating stage 5, a high-pressure hydrophobic medium-temperature heating stage 6, a medium-pressure steam heating stage 7, a high-pressure hydrophobic high-temperature heating stage 8 and a high-pressure steam heating stage 9. The steam pocket saturated steam is condensed into saturated drain after being released heat through a high-pressure steam heating stage 9, the saturated drain enters a high-pressure drain high-temperature heating stage 8 for further releasing heat to form super-cooled drain, and the super-cooled drain enters a deaerator after being released heat through two stages of a high-pressure drain medium-temperature heating stage 6 and a high-pressure drain low-temperature heating stage 3; superheated steam from the first-stage steam extraction of the steam turbine is condensed into saturated drain after being subjected to heat release by the medium-pressure steam heating stage 7, the saturated drain enters the medium-pressure drain medium-temperature heating stage 5 for further heat release to form supercooled drain, and the supercooled drain enters the deaerator after being subjected to heat release by the medium-pressure drain low-temperature heating stage 2; superheated steam from the secondary extraction of the steam turbine is condensed into saturated drain after being released heat through the low-pressure steam heating stage 4, and the saturated drain enters the low-pressure drain low-temperature heating stage 1 to be further released heat to form super-cooled drain and enters the deaerator.
When the device is used, cold air enters from the inlet end of the air preheater and then sequentially passes through the low-pressure hydrophobic low-temperature heating stage 1, the medium-pressure hydrophobic low-temperature heating stage 2, the high-pressure hydrophobic low-temperature heating stage 3, the low-pressure steam heating stage 4, the medium-pressure hydrophobic medium-temperature heating stage 5, the high-pressure hydrophobic medium-temperature heating stage 6, the medium-pressure steam heating stage 7, the high-pressure hydrophobic high-temperature heating stage 8 and the high-pressure steam heating stage 9, and the outlet air temperature of the air preheater reaches a design value after nine-stage heating.
Example 1, a waste incineration power generation project with a primary air temperature of 220 ℃ and a main steam parameter of 4.0MPa/400 ℃. Saturated steam (5.1MPa/266 ℃) from a steam pocket is condensed into saturated hydrophobicity (5.1MPa/266 ℃) after being subjected to heat release in a high-pressure steam heating stage 9, the saturated hydrophobicity (5.1MPa/266 ℃) enters a high-pressure hydrophobic high-temperature heating stage 8 for further heat release to form supercooled hydrophobicity (5.1MPa/215 ℃), the supercooled hydrophobicity (5.1MPa/215 ℃) is decompressed to 2.1MPa and then is subjected to heat release in a high-pressure hydrophobic medium-temperature heating stage 6 to form medium-temperature hydrophobicity (2.1MPa/140 ℃), the medium-temperature hydrophobicity (2.1MPa/140 ℃) is decompressed to 1.0MPa, and then is subjected to heat release in a high-pressure hydrophobic low-temperature heating stage 3 to form low-temperature hydrophobicity (1.0MPa/90 ℃) and then enters a deaerator; superheated steam (1.0MPa/264 ℃) from primary steam extraction of a steam turbine is condensed into saturated hydrophobic (1.0MPa/184 ℃) after heat release of a medium-pressure steam heating stage 7, the saturated hydrophobic (1.0MPa/184 ℃) enters a medium-pressure hydrophobic medium-temperature heating stage 5 to further release heat to form supercooled hydrophobic (1.0MPa/140 ℃), and the supercooled hydrophobic (1.0MPa/140 ℃) enters a deaerator after heat release of a medium-pressure hydrophobic low-temperature heating stage 2 to form low-temperature hydrophobic (1.0MPa/90 ℃); superheated steam (0.4MPa/186 ℃) from the secondary steam extraction of the steam turbine is condensed into saturated hydrophobic (0.4MPa/151 ℃) after heat release of the low-pressure steam heating stage 4, the saturated hydrophobic (0.4MPa/151 ℃) enters the low-pressure hydrophobic low-temperature heating stage 1 to further release heat to form super-cooled hydrophobic (0.4MPa/90 ℃) and then enters a deaerator. The primary air-cooled air (25 ℃) enters from the inlet end of the air preheater and then is sequentially heated to 35.4 ℃ by the low-pressure hydrophobic low-temperature heating stage 1, 38.7 ℃ by the medium-pressure hydrophobic low-temperature heating stage 2, 43.9 ℃ by the high-pressure hydrophobic low-temperature heating stage 3, 130 ℃ by the low-pressure steam heating stage 4, 133 ℃ by the medium-pressure hydrophobic medium-temperature heating stage 5, 141 ℃ by the high-pressure hydrophobic medium-temperature heating stage 6, 175 ℃ by the medium-pressure steam heating stage 7, 180.9 ℃ by the high-pressure hydrophobic high-temperature heating stage 8 and 220 ℃ by the high-pressure steam heating stage 9. Compared with the conventional two-stage steam air preheater scheme, the heat efficiency of the whole plant is relatively improved by about 0.8 percent; all the drained water enters the deaerator at the temperature of 90 ℃ after being subjected to multi-stage cooling, and compared with the mode that the drained water directly enters the deaerator in a saturated water state in the conventional scheme, the scheme greatly reduces the thermal load impact of the drained water on the deaerator; the cold air can stably reach the design value (220 ℃) after being heated by nine stages of sections, and has stronger load fluctuation resistance compared with the conventional scheme.
Example 2, a waste incineration power generation project with a primary air temperature of 220 ℃ and a main steam parameter of 4.0MPa/450 ℃. The air preheater system flow is the same as in case 1, which is a relative plant thermal efficiency improvement of about 1.3% over the conventional two-stage steam air preheater scheme.
Example 3, a waste incineration power generation project with a primary air temperature of 220 ℃ and main steam parameters of 6.4MPa/485 ℃. The air preheater system flow is the same as case 1, which is a relative plant thermal efficiency improvement of about 1.1% over the conventional two-stage steam air preheater scheme.
Claims (3)
1. A steam air preheater system based on energy cascade utilization is characterized by comprising 3 steam heating stages and 6 hydrophobic heating stages; the 3 steam heating stages are respectively a low-pressure steam heating stage, a medium-pressure steam heating stage and a high-pressure steam heating stage along the direction of an air inlet; the 6 hydrophobic heating stages comprise 3 hydrophobic low-temperature heating stages, 2 hydrophobic medium-temperature heating stages and 1 hydrophobic high-temperature heating stage; a low-pressure hydrophobic low-temperature heating stage, a medium-pressure hydrophobic low-temperature heating stage, a high-pressure hydrophobic low-temperature heating stage, a medium-pressure hydrophobic medium-temperature heating stage, a high-pressure hydrophobic medium-temperature heating stage and a high-pressure hydrophobic high-temperature heating stage are respectively arranged along the direction of an air inlet; the heat source of each hydrophobic heating stage is respectively from the hydrophobic of the steam heating stage with corresponding pressure; the arrangement relation of each steam heating stage and each hydrophobic heating stage along the direction of the air inlet is as follows: 1 low-pressure steam heating stage is arranged behind 3 hydrophobic low-temperature heating stages, 1 medium-pressure steam heating stage is arranged behind 2 hydrophobic medium-temperature heating stages, and 1 high-pressure steam heating stage is arranged behind 1 hydrophobic high-temperature heating stage.
2. A steam air preheater system based on energy cascade utilization, as set forth in claim 1, wherein: and the steam sources of the respective heating stages of the low-pressure steam heating stage, the medium-pressure steam heating stage and the high-pressure steam heating stage are respectively from a secondary steam extraction of a steam turbine, a primary steam extraction of the steam turbine and saturated steam of a boiler drum.
3. A steam air preheater system based on energy cascade utilization, as set forth in claim 1, wherein: the heat exchange process of each stage of steam is as follows: saturated steam from a boiler drum is condensed into saturated drain after being subjected to heat release in a high-pressure steam heating stage, the saturated drain enters a high-pressure drain high-temperature heating stage for further heat release to form super-cooled drain, and the super-cooled drain enters a deaerator after being subjected to two-stage heat release in a high-pressure drain medium-temperature heating stage and a high-pressure drain low-temperature heating stage; superheated steam from the first-stage steam extraction of the steam turbine is condensed into saturated drain after being subjected to heat release by a medium-pressure steam heating stage, the saturated drain enters a medium-pressure drain medium-temperature heating stage for further heat release to form supercooled drain, and the supercooled drain enters a deaerator after being subjected to heat release by a medium-pressure drain low-temperature heating stage; superheated steam from the secondary steam extraction of the steam turbine is condensed into saturated drain after being subjected to heat release by the low-pressure steam heating stage, and the saturated drain enters the low-pressure drain low-temperature heating stage to further release heat to form super-cooled drain and enters the deaerator.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112628790A (en) * | 2020-12-17 | 2021-04-09 | 上海双木散热器制造有限公司 | Preheating system of air for combustion of garbage furnace |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112628790A (en) * | 2020-12-17 | 2021-04-09 | 上海双木散热器制造有限公司 | Preheating system of air for combustion of garbage furnace |
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