CN1078033A - Composite phase change heat exchanger - Google Patents
Composite phase change heat exchanger Download PDFInfo
- Publication number
- CN1078033A CN1078033A CN92102776A CN92102776A CN1078033A CN 1078033 A CN1078033 A CN 1078033A CN 92102776 A CN92102776 A CN 92102776A CN 92102776 A CN92102776 A CN 92102776A CN 1078033 A CN1078033 A CN 1078033A
- Authority
- CN
- China
- Prior art keywords
- temperature
- flue gas
- heat exchanger
- safety
- heat
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000008859 change Effects 0.000 title abstract description 3
- 239000002131 composite material Substances 0.000 title abstract description 3
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims abstract description 46
- 239000003546 flue gas Substances 0.000 claims abstract description 46
- 238000005260 corrosion Methods 0.000 claims abstract description 31
- 230000007797 corrosion Effects 0.000 claims abstract description 31
- 239000002184 metal Substances 0.000 claims abstract description 27
- 229910052751 metal Inorganic materials 0.000 claims abstract description 27
- 238000000034 method Methods 0.000 claims abstract description 8
- 238000010438 heat treatment Methods 0.000 claims abstract description 4
- 239000012530 fluid Substances 0.000 claims description 18
- 230000011218 segmentation Effects 0.000 claims 2
- 239000003517 fume Substances 0.000 claims 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 9
- 230000008569 process Effects 0.000 abstract description 6
- 238000011084 recovery Methods 0.000 abstract description 3
- 239000002918 waste heat Substances 0.000 abstract description 3
- 239000000779 smoke Substances 0.000 abstract description 2
- 230000007246 mechanism Effects 0.000 description 7
- 230000008901 benefit Effects 0.000 description 3
- 238000005530 etching Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- 235000019504 cigarettes Nutrition 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000002309 gasification Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
Classifications
-
- 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
Landscapes
- Air Supply (AREA)
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Abstract
The composite phase change heat exchanger, a novel thermotechnical energy-saving device, can be used for recovering the waste heat of the discharged flue gas of boilers and the like. Besides compact structure, high heat transfer rate, and capability of providing energy in two forms of hot air or hot water, the heat exchanger also has the following technical characteristics: 1. the temperature of the metal wall is controlled in two safety areas of low-temperature corrosion by adjusting the phase-change pressure of the intermediate medium at each stage, so that the emission temperature of the flue gas is as low as 105-110 ℃. 2. And the energy quality of recovered energy is improved by a multi-stage heating mode. When the inlet smoke temperature is 250 ℃, the air or water can be heated to more than 160 ℃ in consideration of economy. 3. Simple process, low cost, wide application and short recovery period.
Description
The present invention is a kind of thermal energy-saving equipment, is widely used in the waste heat recovery of boiler and other electro-heat equipment discharging flue gas.Compare with prior art, the present invention except the utility model that contains the inventor and invented (patent No.: 912131136) compact conformation that is possessed, heat transfer efficiency height, can provide the whole advantages of energy of hot-air and two kinds of forms of hot water, also possess following several distinguishing feature:
(1) according to flue gas researching and analysing to metal wall corrosion mechanism, utilize the adjustment of complex phase-change heat exchanger by intermediate medium pressure phase transitions at different levels, realize the characteristics that the metallic walls surface temperature can grading control, when reducing smog discharge temperature greatly, composite phase-change parallel operation and successor devices thereof are all placed in two places of safety of metal cold end corrosion, thereby make the exhaust temperature of boiler smoke from reducing to large-sized station boiler more than 160 ℃, realized a breakthrough of flue gas waste heat recovery technically by means of miscellaneous equipment reached 110 ℃～level below 105 ℃.
(2) according to Exergy Analysis mechanism, by multistage mode of heating, the temperature that is heated fluid is improved step by step, the energy matter that recovers energy is greatly improved.When inlet flue gas temperature is 250 ℃, considering under the economic factors prerequisites such as cost, can be with the level about water or air heat to 200 ℃.
(3) technology is simple, with low cost, payoff period short.
Metal cold end corrosion mechanism and prior art overview
Fig. 1 is exposed to the variation relation curve between metal wall cold end corrosion speed Ve and tube wall temperature Tw in the flue gas.Concerning with a kind of metal, the temperature value of three characteristic point A, B, C is different with the difference of corrosive gas composition in the flue gas among the figure.In coal-burning boiler, the temperature span that A, B, C are 3 is generally 130～140 ℃, between 100 ℃～110 ℃ and 60 ℃～70 ℃.Claim that A point is first place of safety with the zone on the right side, the zone between 2 of title B, the C is second place of safety.When the metallic walls surface temperature that contacts with flue gas was in these two zones, the cold end corrosion speed of metal was considered to allow.Why the smog discharge temperature of large-sized station boiler can reach 100 ℃～level below 110 ℃, is exactly to have considered its successor devices, the reason that has all entered second place of safety as deduster, blower fan etc.
Because the metallic walls that contacts with flue gas also is subjected to the influence of opposite side cold fluid, its wall temperature must be lower than the temperature of flue gas stream, therefore as not taking special version, flue gas is reduced to and the corresponding temperature in metal cold end corrosion second place of safety from higher temperature, as 105 ℃ process, the part wall surface temperature of heat exchanger is bound to drop in the strong cold end corrosion district.Like this, the exhaust temperature of flue gas is generally always got than the first place of safety lower limit temperature t among Fig. 1
wOn the general level of high tens degree.Discuss respectively at the present situation of several typical heat transmission equipments of present use below.
(1) to general shell-and-tube heat exchanger, above-mentioned conclusion is fairly obvious.With one way adverse current dividing wall type heat exchanger is example, its tube wall temperature t
w, flue-gas temperature t
gWith the temperature t f that is heated fluid along the distribution of flue gas flow as shown in Figure 2.Because wall temperature is a continually varying, tw must be taken in first place of safety.Only in this way, the unlikely generation heavy corrosion of the metal wall that the whole and flue gas in the heat exchanger is contacted.
(2) as for heat-pipe heat exchanger, though the wall temperature of each heat extraction pipe is a discrete magnitude, along the flow of flue gas direction, the general trend that the wall temperature of each heat extraction pipe is still pressed the tw curve among Fig. 2 changes, so its design exhaust gas temperature is still higher.The possessor proposes to the greatest extent, the plurality of rows heat pipe that heavy corrosion will take place in the opposite heat tube heat exchanger is handled especially, promptly increase considerably this plurality of rows heat pipe cold junction one side and be heated thermal resistance between fluid, make tube wall temperature more near the higher flue-gas temperature of temperature, thereby the heat pipe that strong corrosion will take place in these predictions is controlled in the first higher place of safety of temperature by force.This in fact idea is not reduced to caused cold end corrosion problem the suitable low temperature process from solving flue gas in essence from higher temperature, now is analyzed as follows:
1. extremely ideally, as do not consider on the heat-transfer mechanism irrationality and technologic can not realization property, think that the heat exchange thermal resistance of heat pipe cold junction one side and cold fluid is an infinitely large quantity, the metallic walls surface temperature equals contacted with it flue-gas temperature.Even yet under this extreme assumed condition, the exhaust temperature of flue gas still must not be lower than the temperature that A is ordered among Fig. 1, otherwise always the plurality of rows heat pipe of heat exchange of heat pipe is in the deep-etching district.The suitable level of the second place of safety temperature of therefore attempting to use general heat exchange of heat pipe that exhaust gas temperature is reduced to the metal cold end corrosion is impossible, Here it is at present the flue gas design exhaust temperature of heat exchange of heat pipe always get more than 160 ℃ even higher cause.
2. the thermal resistance that increases considerably heat pipe cold side one end will cause heat transfer efficiency to reduce greatly, and structure is artificially huge, and in fact above-mentioned imagination is difficult to realize.
3. the flow of flue gas in the boiler operatiopn, always there is fluctuation in temperature, and it is therefore in service that actual to be in the heat pipe that deep-etching will take place the heat pipe deep-etching state under and prediction always identical.
Existence just because of the problems referred to above, although the exhaust temperature with flue gas is controlled at more than 160 ℃, the cold end corrosion phenomenon of common heat exchange of heat pipe is still very serious in actual applications, certainly let alone consider the exhaust temperature of flue gas is controlled at second place of safety that reaches the metal cold end corrosion, about about 105 ℃ temperature levels.
(3) in the station boiler in order to prevent the cold end corrosion in the last grade air preheater, adopted warm-air drier.Adopt the basic thought of warm-air drier to remain, make it be in traditional idea in the first higher place of safety of temperature based on attempting raising and the contacted wall surface temperature of flue gas.In fact adopt warm-air drier fundamentally not solve the cold end corrosion problem, reason is:
Though 1. obtain to a certain degree raising through the pre-warmed cold air temperature of dim blower fan, dim blower fan outlet must be lower than the exhaust temperature of flue gas.Therefore, when the exhaust temperature of flue gas is low, still has part metals in the last grade air preheater and be operated in the corrosion region.This just some station boilers the last grade air preheater is made as the reason of periodic replacement form.
2. not only additionally expended a steam of regularly measuring with dim blower fan preheated air, and reduced the temperature and pressure between cold fluid and hot fluid in the air preheater, heat transfer efficiency has been reduced, thereby cause device macroeconomic performance decrease.
In sum, various existing heat exchangers all can't make the exhaust temperature of flue gas reduce to enough low level at present, and do not produce serious cold end corrosion phenomenon.Set up warm-air drier and also can only reach the purpose of alleviating cold end corrosion to a certain extent.
Anticorrosive mechanism of the present invention, version and major advantage
Be not difficult to find out by analysis prior art, guaranteeing that the boiler successor devices is under the prerequisite of cold end corrosion place of safety, the key technology that makes flue gas be reduced to enough low temperature levels is to make in the temperature-fall period of flue gas through a desirable heat exchanger, guarantee in the heat exchanger that temperature with the contacted whole metal surfaces of flue gas directly is not subjected on the temperature regime of contacted flue gas with it, and can more balancedly be controlled in the less temperature range of a setting, make it to be in the problem in the cold end corrosion place of safety.Adopt basic design provided by the present invention and corresponding structure form can solve this key technical problem fully.
Heat exchanger structure form below in conjunction with shown in the accompanying drawing 3,4 is illustrated anticorrosive mechanism of the present invention.
Fig. 3 is a general illustration of the present invention, is become by some grades of phase-change heat-exchanger serial connection faces, and wherein 1 to 6 represents flue gas respectively, is heated fluid, the first order of heat exchanger, the second level, n level, pressure-regulating device.The version of every grade of independent phase-change heat-exchanger is roughly similar, as shown in Figure 4,1 is cigarette institute among the figure, 2 for being heated fluid, and 3 is metal tube, and 4 is dividing plate, 5 is pressure-regulating device, 6 is water pipe, and 7 is fin, and the concrete size of each grade phase-change heat-exchanger, the selection of Pressure Control Unit form change with the difference of medium pressure phase transition.Heated fluid can be that air, water or air generally adopt the form of connecting with a kind of heated fluid with water, so that this fluid is heated to higher temperature levels.The phase-change heat-exchanger of two kinds of forms shown in Figure 4 can adopt, but concerning adding hot-air, can only be with the b type among Fig. 4, to guarantee higher heat transfer efficiency.
The corresponding work process is: when plunderring metal tube 3 outside the flue gas stream 1, make intermediate medium 8 gasifications in the pipe, the wall of the medium that has gasified by the water pipe 6 among Fig. 4 a is to its inboard water heating, or the wall that passes through metal tube 3 upsides among Fig. 4 b heats the cold fluid outside it 2, and liquefaction again, circulation is more than.
In this heat exchanger that this patent provided, flue gas in previous stages phase-change heat-exchanger stream and the temperature that is heated fluid all are in higher level, and the metal wall what is easy to this is controlled in first place of safety.Therefore, the last grade phase-change heat-exchanger only, be that n level heat exchanger among Fig. 3 need be considered the cold end corrosion problem, and require the outlet cigarette temperature of this grade heat exchanger to reach and the suitable lower temperature levels in metal cold end corrosion second place of safety, the successor devices of boiler is still located in the place of safety.Consider that the inboard of whole metal tube 3 shown in Figure 4 carrying out the phase-change heat-exchange process, the outside carry out be and flue gas between the convection heat transfer process, although therefore along flue gas flow direction, the temperature of metal tube outside flue gas constantly changes on the different longitudinal position, but because the phase-change heat-exchange thermal resistance is significantly smaller than convection heat transfer thermal resistance (several reach two more than the magnitude), and be in the same space of mutual perforation with the intermediate medium in the whole metal planches of one-level, so the temperature of these metal walls is all very approaching, the state that is decided by intermediate medium fully, thus whole pipe fittings that can easily this level be contacted with flue gas are controlled in the place of safety of cold end corrosion.For example in this grade phase-change heat-exchanger, suppose that flue gas reduces to 105 ℃ from 170 ℃, be-0.3 * 10 if the pressure phase transition of intermediate medium is controlled at gauge pressure
5Pa, then whole metallic surface temperatures of contacting with flue gas of this level are about 90 ℃, are in fully in the place of safety of cold end corrosion, thereby have avoided strong cold end corrosion problem.
Compared with prior art, the present invention has following advantage:
(1) based on the research of metal cold end corrosion mechanism, utilize version provided by the present invention, guaranteeing that heat exchanger self and successor devices thereof all are under the prerequisite of cold end corrosion place of safety, smog discharge temperature is significantly reduced, this technical conceive proposes first for the present invention.
(2) intermediate medium can be in little negative pressure and direct draught work.When load variations is big, can be controlled the pressure of middle medium by means of the adjustment that is heated fluid flow.The flow adjustment that is heated fluid can be by manually carrying out, or microcomputer carries out automatically.
(3) adopt heat form step by step, part or all of fluid is heated to higher temperature levels, to improve the energy matter that reclaims heat.
Claims (4)
1, a kind of thermal energy-saving equipment that is used to recycle hot equipment exhausting fume afterheats such as boiler is characterized in that:
A. the intermediate medium of whole metal pipe-walls inboard of contacting with flue gas of each section is in respectively in the space that can connect mutually, as shown in Figure 4.
B. by directly aligning and control the method for intermediate medium pressure, will all be in the place of safety of flue gas low-temperature corrosion with the contacted metal surface of flue gas in the heat exchanger with in contacted metal pipe-wall of flue gas and the successor devices thereof.
C. adopt the form of segmentation heating, segmentation control, improved step by step so that be heated the temperature levels of fluid, as shown in Figure 3.
2, device according to claim 1 is characterized in that the intermediate medium of some section of heat exchanger is in respectively in the space that connects mutually.
3, device according to claim 1, it is characterized in that when the high temperature section with heat exchanger is controlled in the place of safety that is in more than the dew point, method by direct levelling intermediate medium state, the metal wall temperature that may be in the higher strong cold end corrosion district of temperature reduces by force, makes it to be in second place of safety.
4, device according to claim 1 is characterized in that heat exchanger is multistage layout, and every section can flexible configuration.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN92102776A CN1091235C (en) | 1992-04-23 | 1992-04-23 | Compound phase change heat exchanger |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN92102776A CN1091235C (en) | 1992-04-23 | 1992-04-23 | Compound phase change heat exchanger |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1078033A true CN1078033A (en) | 1993-11-03 |
| CN1091235C CN1091235C (en) | 2002-09-18 |
Family
ID=4939840
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN92102776A Expired - Fee Related CN1091235C (en) | 1992-04-23 | 1992-04-23 | Compound phase change heat exchanger |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1091235C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102910104A (en) * | 2012-11-14 | 2013-02-06 | 青岛奥环新能源科技发展有限公司 | Composite phase-change energy storage movable heat supply vehicle |
| CN105277027A (en) * | 2015-11-05 | 2016-01-27 | 吉林省电力科学研究院有限公司 | Phase-change heat exchanger and heat exchange method thereof |
-
1992
- 1992-04-23 CN CN92102776A patent/CN1091235C/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102910104A (en) * | 2012-11-14 | 2013-02-06 | 青岛奥环新能源科技发展有限公司 | Composite phase-change energy storage movable heat supply vehicle |
| CN102910104B (en) * | 2012-11-14 | 2014-10-29 | 青岛奥环新能源科技发展有限公司 | Composite phase-change energy storage movable heat supply vehicle |
| CN105277027A (en) * | 2015-11-05 | 2016-01-27 | 吉林省电力科学研究院有限公司 | Phase-change heat exchanger and heat exchange method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1091235C (en) | 2002-09-18 |
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| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |