CN102012039B - Forced circulation air preheat system - Google Patents
Forced circulation air preheat system Download PDFInfo
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- CN102012039B CN102012039B CN201010601629.3A CN201010601629A CN102012039B CN 102012039 B CN102012039 B CN 102012039B CN 201010601629 A CN201010601629 A CN 201010601629A CN 102012039 B CN102012039 B CN 102012039B
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- heat exchanger
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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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Abstract
The invention discloses a forced circulation air preheat system which is characterized in that a lower-section air preheater is internally provided with at least two gas ducts and at least two air flues, wherein the numbers of the gas ducts and the air flues are same; each gas duct is isolated from each air flue; the gas ducts and the air flues are arranged at intervals; a lower-section heat exchange tube is arranged between each two adjacent gas duct and air flue, and all the lower-section heat exchange tubes are communicated; and a transporter is arranged between the water inlet and water outlet of each lower-section heat exchange tube, and is connected with a circuit controller. Because the forced circulation air preheat system is subject to secondary heat exchange by means of a medium, the medium generates phase change in the lower-section heat exchange tubes so as to maintain the wall surface temperature of the lower-section heat exchange tubes to be equal to the phase change temperature of water, and the pressure in the lower-section heat exchange tubes is adjusted in the gas ducts so as to control the tube wall temperature of the lower-section heat exchange tubes to be higher than the acid dew point temperature of flue, thus avoiding the parts, which are positioned in the gas ducts, of the lower-section heat exchange tubes from acid corrosion, thereby solving the problem of low temperature corrosion caused by the smoke removal temperature reduction of the air preheater.
Description
Technical field
The present invention relates to boiler plant heat recovery technology field, particularly a kind of air preheating system that reduces boiler exhaust gas heat loss and make full use of waste heat of realizing by forced circulation.
Background technology
Existing boiler plant, as all kinds of high pressure, super-pressure, subcritical pressure boiler, the exhaust gas temperature of its air preheater rear pass is higher, in order to improve boiler thermal output, conventionally using air preheater as flue surface, carries out air and the exchange of flue gas direct heat.
The wider product of application mainly contains tubular air preheater and regenerative air preheater at present.From former boiler design technique, conventional tubular or regenerative air preheater be for avoiding occurring cold end corrosion and stifled ash, and for example, when acid dew point is 80 ℃, exhaust gas temperature will be higher than 135 ℃ (if import wind-warm syndrome 20 ℃).As need further reduce the exhaust gas temperature of boiler and guarantee that the tube wall temperature of air preheater is not less than flue gas dew point, adopting conventional art is to accomplish.Therefore conventionally when guaranteeing safe operation of the boiler, exhaust gas temperature need to design highlyer, thereby causes boiler exhaust gas heat loss.
The import wind-warm syndrome of existing air preheater is along with can change season simultaneously, and exhaust gas temperature is also subject to the impacts such as load, burning, when the wall surface temperature of air preheater is during lower than acid dew-point temperature, will there is cold end corrosion and cause local dust stratification, SR increase, heating surface fouling etc. in air preheater end, thereby affect the thermal efficiency of boiler.
Summary of the invention
The technical problem that the present invention mainly solves is to provide a kind of forced circulation air preheating system, the cold end corrosion that this forced circulation air preheating system produces in the time of can avoiding reducing the exhaust gas temperature of air preheater, reduce the exhaust gas temperature of air preheat simultaneously, improve the utilization ratio of fume afterheat.
In order to address the above problem, the invention provides a kind of forced circulation air preheating system, this forced circulation air preheating system comprises hypomere air preheater, in this hypomere air preheater, be provided with at least two flues and at least two air channels that quantity is identical, each flue and air channel are mutually isolated, flue gas and air do not carry out direct heat transfer by tube wall, and flue is adjacent with interval, air channel, between this adjacent flue and air channel, be respectively equipped with the hypomere heat exchanger tube of connection, between the water inlet end of this hypomere heat exchanger tube and water side, be provided with conveying device, this conveying device is connected with circuit controller.
Preferably, described hypomere heat exchanger tube is in parallel distributes.
Preferably, between the water side of described hypomere heat exchanger tube and conveying device, being provided with the expansion tank of adjustable water pressure is connected with conveying device and accepts the first switch that circuit controller is controlled.
Preferably, described the first switch comprises electrically operated valve or electromagnetic valve.
Preferably, described conveying device comprises water circulating pump.
Preferably, described forced circulation air preheating system also comprises the stage casing air preheater being connected with hypomere air preheater, and wherein on this stage casing air preheater, two air channels are arranged in a crossed manner.
Preferably, described forced circulation air preheating system also comprises the epimere air preheater being connected with stage casing air preheater, this epimere air preheater is provided with the conduit being connected with water cooler with epimere heat exchanger tube in it, and this conduit is provided with the second switch that is connected and controls conduit condensing water flow with described circuit controller.
Preferably, described gate-controlled switch comprises electrically operated valve or electromagnetic valve.
Preferably, the condensing water conduit hydraulic pressure of the entrance of described epimere heat exchanger tube, outlet hydraulic pressure and introducing, the heat regenerative system of drawing is identical.
Preferably, at least two of described hypomere air preheater outlet air channels are higher than described at least two gas approach.
Forced circulation air preheating system of the present invention, in this hypomere air preheater, be provided with at least two flues and at least two air channels that quantity is identical, each flue and air channel are mutually isolated, flue gas and air do not carry out direct heat transfer by tube wall, and flue is adjacent with interval, air channel, the hypomere heat exchanger tube that is respectively equipped with connection between this adjacent flue and air channel, is provided with conveying device between the water inlet end of this hypomere heat exchanger tube and water side, and this conveying device is connected with circuit controller.During work, by the water that is positioned at the hypomere heat exchanger tube of flue, absorb heat, make water become steam, this steam is passed to heat in the hypomere heat exchanger tube in air channel, this steam makes to raise with the air themperature contacting in hypomere heat exchanger tube, simultaneously with air contact process in make steam condense into water to flow in header, this water carries out forced circulation under described conveying device is carried, and realizes Continuous Heat Transfer.
Because forced circulation air preheating system is to carry out secondary heat exchange by medium, medium undergoes phase transition in hypomere heat exchanger tube, make the wall surface temperature of hypomere heat exchanger tube maintain the phase transition temperature of water, in flue, by the pressure (being expansion tank pressure) in adjusting hypomere heat exchanger tube, hypomere heat exchanger tube wall temperature (water temperature) is controlled on flue gas acid dew point temperature all the time, avoid hypomere heat exchanger tube to be positioned at the pipeline generation acid corrosion of flue, thereby solve the problem of traditional air preheater cold end corrosion.
When the coal combustion speciogenesis of boiler changes, acid dew-point temperature also can change, and the phase transition temperature by medium in expansion tank pressure change hypomere heat exchanger tube, is controlled at the wall surface temperature of hypomere heat exchanger tube on acid dew-point temperature all the time, prevents the corrosion of acid dew.By circuit controller, control gate-controlled switch simultaneously and be greater than to regulate water cooler condensate flow, cigarette temperature after water cooler is changed, to change the flue-gas temperature after hypomere air preheater, thereby realize the object that prevents boiler flue corrosion and reduce to greatest extent exhaust gas temperature.
Accompanying drawing explanation
Fig. 1 is forced circulation air preheating system example structure schematic diagram of the present invention;
Fig. 2 is along A-A direction sectional structure schematic diagram;
Fig. 3 is another example structure schematic diagram of forced circulation air preheating system of the present invention.
Below in conjunction with embodiment, and with reference to accompanying drawing, the realization of the object of the invention, functional characteristics and advantage are described further.
The specific embodiment
As shown in Figure 1, Figure 2 and Figure 3, the invention provides a kind of forced circulation air preheating system embodiment.
This forced circulation air preheating system comprises: hypomere air preheater, in this hypomere air preheater, be respectively equipped with at least two flues (exhaust gases passes) and at least two air channels (air duct) that quantity is identical, the quantity of flue is identical with the quantity in air channel.Each flue and air channel are mutually isolated, flue gas and air do not carry out direct heat transfer by tube wall, and flue is adjacent with interval, air channel, between this adjacent flue and air channel, be respectively equipped with the hypomere heat exchanger tube of connection, between the water inlet end of this hypomere heat exchanger tube and water side, be provided with conveying device, as adopting the water circulating pump of variable frequency adjustment, this conveying device is connected with circuit controller; Described hypomere heat exchanger tube can be in parallel distribution.
Between the water side of described hypomere heat exchanger tube and conveying device, be provided with the expansion tank of adjustable water pressure and be connected with conveying device and accept the first switch that circuit controller is controlled, this first switch comprises electrically operated valve or electromagnetic valve.
During work, flue gas is from top to bottom by described hypomere air preheater.By the water that is positioned at the hypomere heat exchanger tube of flue, absorbed the heat of flue gas, make water become steam, this steam is passed to heat the hypomere heat exchanger tube that is positioned at air channel, this steam raises the air themperature contacting with hypomere heat exchanger tube outer wall, simultaneously with air contact process in make steam in hypomere heat exchanger tube condense into water to flow in header, this water carries out forced circulation under described conveying device is carried, and realizes Continuous Heat Transfer.
Because forced circulation air preheating system is to carry out secondary heat exchange by medium, medium undergoes phase transition in hypomere heat exchanger tube, make the wall surface temperature of hypomere heat exchanger tube maintain the phase transition temperature of water, in flue, by the pressure (being expansion tank pressure) in adjusting hypomere heat exchanger tube, make hypomere heat exchanger tube wall temperature (water temperature) be controlled at all the time on acid dew-point temperature, avoid hypomere heat exchanger tube to be positioned at the pipeline generation acid corrosion of flue, thereby solve the problem of traditional air preheater cold end corrosion.
When the coal combustion speciogenesis of boiler changes, acid dew-point temperature also can change, can the wall surface temperature of hypomere heat exchanger tube be controlled on acid dew-point temperature all the time by the phase transition temperature of medium in expansion tank pressure change hypomere heat exchanger tube, prevent the corrosion of acid dew.
In upper embodiment, water source in described epimere heat exchanger tube comes from the condensate water of steam turbine water supply heat back system, hydraulic pressure is the pipeline pressure that attracts condensate water, and the condensing water conduit hydraulic pressure of the entrance of described epimere heat exchanger tube, outlet hydraulic pressure and introducing, the heat regenerative system of drawing is identical; At least two outlet air channels of described hypomere air preheater are higher than described at least two gas approach.
As shown in Figure 3, described forced circulation air preheating system also comprises the stage casing air preheater being connected with hypomere air preheater, wherein on this stage casing air preheater, two air channels are arranged in a crossed manner, can make the flue gas in flue fully contact with air channel outer wall, the heat exchange coefficient of flue gas in the air in raising air channel and flue.
On the air preheater of described stage casing, be provided with epimere air preheater, this epimere air preheater is provided with epimere heat exchanger tube, this epimere heat exchanger tube and water cooler connect, this conduit is provided with the second switch that is connected and controls conduit condensing water flow with described circuit controller, and this second switch comprises electrically operated valve or electromagnetic valve.
Technique effect for better explanation the present invention reaches, illustrates the course of work.
Described water cooler is the gas one water heat-exchanger rig of flue gas and condensate water, structure and economizer are similar, the high-temperature flue gas of 330-350 ℃ of left and right can be reduced to 250-270 ℃ of left and right, high-temperature flue gas and low-temperature condensate carry out heat exchange, and water-cooled source comes from the condensate water of water supply heat back system.Can control the flow of inlet water that second switch regulates water cooler by circuit controller as required, realize and control the cooldown rate of water cooler to flue gas.
Stage casing heat exchanger tube on the air preheater of stage casing adopts oblique layout, and air is along pipe to upwards flowing in the heat exchanger tube of the stage casing of this oblique layout, and flue gas flows downward outward and washes away heat exchanger tube at stage casing heat exchanger tube.This stage casing air preheater can be reduced to the high-temperature flue gas of 250-270 ℃ 160 ℃ of left and right, normal temperature air is heated to temperature required level simultaneously, supplies with boiler-burner and burns.
Hypomere air preheater can adopt four passages, and wherein two passages are flue, and two passages are air channel, and each flue and air channel are mutually isolated, and flue gas and air do not carry out direct heat transfer by tube wall, and flue is adjacent with interval, air channel.Hypomere heat exchanger tube on hypomere air preheater adopts parallel transistor to arrange and puts, according to circumstances hypomere heat exchanger tube also can adopt horizontal positioned, can vertical or oblique placement, in hypomere heat exchanger tube for aqueous medium carries out carbonated drink phase-change heat-exchange.Hypomere heat exchanger tube absorbs flue gas heat in flue, makes the water evaporation in hypomere heat exchanger tube produce steam, and heat is delivered to the hypomere heat exchanger tube that is positioned at air channel, makes the atmosphere temperature rising in air channel, exhaust gas temperature is down to lower; Make steam in hypomere heat exchanger tube condense into water flows in header and carries out next circulation simultaneously.By be connected expansion tank with described hypomere air preheater, control water lateral pressure in hypomere heat exchanger tube, by water circulating pump, forced to promote the reciprocation cycle of carbonated drink, for circulation provides power and carries out moisturizing.
In this system, by circuit controller, it is carried out to multi-faceted adjusting, can make the flue-gas temperature after air preheater can be down to alap level, reach the object that reduces heat loss due to exhaust gas.Because exhaust gas temperature is reduced, flue gas actual flow will reduce thereupon, so also corresponding reducing of the flow velocity of the heat exchanger tube in sweep of gases air preheater, heat exchanger tube will be improved by the abrasion condition of flying dust in flue gas, the stifled ash of Antidewing.
The foregoing is only the preferred embodiments of the present invention; not thereby limit the scope of the claims of the present invention; every equivalent structure or conversion of equivalent flow process that utilizes description of the present invention and accompanying drawing content to do; or be directly or indirectly used in other relevant technical fields, be all in like manner included in scope of patent protection of the present invention.
Claims (6)
1. forced circulation air preheating system, it comprises hypomere air preheater, it is characterized in that:
In this hypomere air preheater, be provided with at least two flues and at least two air channels that quantity is identical, each flue and air channel are mutually isolated, and flue is adjacent with interval, air channel, between this adjacent flue and air channel, be respectively equipped with the hypomere heat exchanger tube of connection, between the water inlet end of this hypomere heat exchanger tube and water side, be provided with the conveying device of forced water circulation, this conveying device is connected with circuit controller, described hypomere heat exchanger tube is in parallel to distribute, in described hypomere heat exchanger tube for aqueous medium carries out carbonated drink phase-change heat-exchange, hypomere heat exchanger tube wall temperature is controlled on flue gas acid dew point temperature all the time, between the water side of described hypomere heat exchanger tube and conveying device, being provided with the expansion tank of adjustable water pressure is connected with conveying device and accepts the first switch that circuit controller is controlled, described hypomere heat exchanger tube water inlet end and water side are equipped with header, described forced circulation air preheating system also comprises the stage casing air preheater being connected with hypomere air preheater, wherein the stage casing heat exchanger tube of walking air on this stage casing air preheater is arranged in a crossed manner, this stage casing heat exchanger tube is communicated with the air channel on hypomere air preheater, described forced circulation air preheating system also comprises the epimere air preheater being connected with stage casing air preheater, this epimere air preheater is provided with epimere heat exchanger tube, this epimere heat exchanger tube is communicated with water cooler by conduit, this conduit is provided with the second switch that is connected and controls conduit condensing water flow with described circuit controller.
2. forced circulation air preheating system according to claim 1, is characterized in that:
Described the first switch comprises electrically operated valve.
3. forced circulation air preheating system according to claim 1, is characterized in that:
Described conveying device comprises water circulating pump.
4. forced circulation air preheating system according to claim 1, is characterized in that:
Described second switch comprises electrically operated valve.
5. forced circulation air preheating system according to claim 1, is characterized in that:
The condensing water conduit hydraulic pressure of the entrance of described epimere heat exchanger tube, outlet hydraulic pressure and introducing, the heat regenerative system of drawing is identical.
6. forced circulation air preheating system according to claim 1, is characterized in that:
The outlet at least two air channels of described hypomere air preheater is higher than the entrance of described at least two flues.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010601629.3A CN102012039B (en) | 2010-12-22 | 2010-12-22 | Forced circulation air preheat system |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010601629.3A CN102012039B (en) | 2010-12-22 | 2010-12-22 | Forced circulation air preheat system |
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| CN102012039A CN102012039A (en) | 2011-04-13 |
| CN102012039B true CN102012039B (en) | 2014-01-22 |
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| CN201010601629.3A Expired - Fee Related CN102012039B (en) | 2010-12-22 | 2010-12-22 | Forced circulation air preheat system |
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Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102345997B (en) * | 2011-09-29 | 2012-11-28 | 熊泽宇 | Dew point corrosion resistant method for flue gas heat exchanger |
| CN103148502B (en) * | 2011-12-06 | 2015-06-03 | 攀钢集团西昌钢钒有限公司 | Method for alleviating corrosion of boiler preheater |
| CN107860022B (en) * | 2017-11-28 | 2023-10-24 | 西安交通大学 | Variable flue section tubular air preheater |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN2368001Y (en) * | 1999-04-23 | 2000-03-08 | 杨本洛 | Integrated heat-pipe type compound phase transition heat exchanger |
| CN200972137Y (en) * | 2006-11-15 | 2007-11-07 | 上海宁松热能环境工程有限公司 | Combined water thermal media air preheater |
| CN201582842U (en) * | 2009-11-17 | 2010-09-15 | 中国石油化工集团公司 | Combined air preheater |
| CN202002140U (en) * | 2010-12-22 | 2011-10-05 | 深圳中兴节能环保股份有限公司 | Forced circulation air preheating system |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0631696B2 (en) * | 1985-03-22 | 1994-04-27 | 三菱重工業株式会社 | Combined gas preheater |
| JPS62175513A (en) * | 1986-01-28 | 1987-08-01 | Babcock Hitachi Kk | Method for direct igniting and energizing of fine powder coal for boiler |
| CN201434623Y (en) * | 2009-05-18 | 2010-03-31 | 上海泽宇机电设备制造有限公司 | Two-phase flow water heat medium heat exchange system |
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2010
- 2010-12-22 CN CN201010601629.3A patent/CN102012039B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2368001Y (en) * | 1999-04-23 | 2000-03-08 | 杨本洛 | Integrated heat-pipe type compound phase transition heat exchanger |
| CN200972137Y (en) * | 2006-11-15 | 2007-11-07 | 上海宁松热能环境工程有限公司 | Combined water thermal media air preheater |
| CN201582842U (en) * | 2009-11-17 | 2010-09-15 | 中国石油化工集团公司 | Combined air preheater |
| CN202002140U (en) * | 2010-12-22 | 2011-10-05 | 深圳中兴节能环保股份有限公司 | Forced circulation air preheating system |
Non-Patent Citations (2)
| Title |
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| JP昭61-217694A 1986.09.27 |
| JP昭62-175513A 1987.08.01 |
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