CN204404203U - A kind of boiler ultra low-ash back-end ductwork system - Google Patents
A kind of boiler ultra low-ash back-end ductwork system Download PDFInfo
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- CN204404203U CN204404203U CN201520004003.2U CN201520004003U CN204404203U CN 204404203 U CN204404203 U CN 204404203U CN 201520004003 U CN201520004003 U CN 201520004003U CN 204404203 U CN204404203 U CN 204404203U
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- flue gas
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- end ductwork
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Abstract
The utility model relates to a kind of boiler ultra low-ash back-end ductwork system, comprise economizer, denitrating system, air preheater, high-temperature dust removal system is provided with before denitrating system after economizer, denitrating system is communicated with desulphurization system by the air preheater that connects successively, flue gas waste heat recovery system, air-introduced machine, and desulphurization system is connected with chimney.The utility model can reduce the equipment volume of denitrating system, air preheater, flue gas waste heat recovery system, desulphurization system etc., can the original measure removal for preventing and treating wearing and tearing, burn into dust stratification, stifled ash, reduce cost, simplify the structure, decrease space.
Description
Technical field
The utility model relates to a kind of boiler flue system, the dust contained flue gas concentration of boiler economizer outlet significantly can be reduced, makes whole back-end ductwork all be in the boiler flue system of almost ashless duty in particular to a kind of, belong to thermal power generation field.
Background technology
Current boiler back end ductwork system, in the flue after flue gas dust collecting system is generally arranged on air preheater, before desulfurizer.During due to boiler combustion, especially during coal-fired boiler combustion, can produce a large amount of ashes, the equipment worked under high dust flue gas environment is all subject to the impact of ash.
When ash-laden gas flows through denitrating system, the elements such as Na, K, Si, As of containing in flying dust can make catalyst contamination or poisoning, and contain the flue gas wearing and tearing reactor of dust particale and make cellular catalyst blockage, reduce denitration efficiency, increase operating cost.Also scholar is had to make improvement to denitrating system; cleaner is increased to remove the bulky grain dust entering denitrating system at the intake section of denitrating system; but this cleaner is only to remove the bulky grain dust entering denitrating system; for denitrating system service; its dust removing effects does not reach the emission request of country far away, and the further cleaner in flue is still indispensable.And the flue after denitration device has still been in dust state, these equipment have still been operated in the environment of ash.
Air preheater and flue gas waste heat recovery system are subject to the wearing and tearing of ash, the impact of dust stratification, heat transfer coefficient are declined, reliability decrease; The heat exchange corrugated plating of air preheater, owing to will consider the effect of dust stratification, so wave pitch is comparatively large, result also in the reduction of the coefficient of heat transfer.Gas cooler after being positioned at air preheater, more can be subject to the impact may blocking up ash, cause heat exchange property to decline fast, flow resistance sharply raises.
Figure 1 shows that the existing boiler flue system before transformation, the ash-laden gas produced that burns in boiler furnace (not shown) enters economizer, denitrating system, air preheater, flue gas waste heat recovery system, electrostatic precipitator, air-introduced machine and desulphurization system successively under the effect of flue entrance at air-introduced machine, eventually passes through chimney and discharges.Denitrating system adopts selective catalytic reduction, i.e. SCR method.When temperature about 300 DEG C, catalyst is in greater activity, therefore the denitration efficiency of 90% can be reached, but the elements such as Na, K, Si, As of containing in flying dust, cause catalyst contamination or poisoning, reduce catalyst life, and contain the flue gas wearing and tearing reactor of dust particale and make cellular catalyst blockage, therefore the denitration efficiency of 90% will be kept then to need higher investment and operating cost.Air preheater runs in high concentration flying dust environment, and this brings the problem of two aspects.On the one hand, there is more serious wear problem in air preheater.Through measuring, in rated load operation situation, the average flying dust concentration of air preheater position reaches 18.6g/kg.Because flying dust concentration is higher, cigarette speed is fast, air preheater serious wear, and therefore need to adopt rigidity is high, abrasion resistance properties is good steel as heat exchange tube material during design, the manufacturing cost of air preheater is very high.On the other hand, because the dust particale in flue gas is attached on heat exchange surface, cause heat exchanger heat exchange thermal resistance to increase, make exhaust gas temperature higher.In the actual moving process of this comparative example, time at full capacity, exhaust gas temperature is 150 DEG C, higher than design load 130 DEG C.And exhaust gas temperature often raises 10 DEG C, boiler efficiency reduces by 0.5%.Flue gas waste heat recovery system is arranged between air preheater and electrostatic precipitation, and flue gas heat recovery system comprises inlet header 61, outlet header 62 and heat-exchanging tube bundle 63, and heat-exchanging tube bundle is spiral fin coil.Because the flue gas heat recovery system works in this comparative example is in the flue gas environment of high ash concentration, be very easy to dust stratification between the fin of heat-exchanging tube bundle and cause flue blockage, flue gas waste heat recovery system heat exchange efficiency is caused to decline on the one hand, bring very large resistance on the other hand whole flue running environment, air-introduced machine is caused to exert oneself increase, therefore be generally not less than 10mm according to spiral fin coil when the spacing of fin of heat-exchanging tube bundle designs in dusty circumstances, H type finned tube is not less than 17mm and designs.In the prior art, spacing of fin is designed to 10mm.In rated power operation situation, the cigarette temperature of entering of flue gas waste heat recovery system is 135 DEG C, and exhaust gas temperature is 110 DEG C, and now the inflow temperature of flue gas waste heat recovery system is 80 DEG C, and flow is 65t/h, and leaving water temperature is 95-105 DEG C.Electrostatic precipitator is arranged in the port of export of air preheater, and design efficiency of dust collection is 99.4%, and house outlet dust content is 200mg/m
3.This electrostatic precipitator initial cost and operating cost higher, by boiler load variable effect in running, can not absolute guarantee's efficiency of dust collection, the discharge standard that country is stricter from now on cannot be tackled.Flue gas after dedusting is discharged boiler exhaust gas system through air-introduced machine, desulfurizer and chimney and is entered air.
Therefore, the reliability and the economy that are arranged at the various equipment of boiler back end ductwork are all subject to the impact of flue gas containing ash concentration, cause performance degradation.The normal operation of boiler can also be affected time serious.
Utility model content
The purpose of this utility model is the deficiency overcoming above-mentioned existing equipment technology, and a kind of boiler ultra low-ash back-end ductwork system is provided, bring the guarantee of environment can to the reliably working of equipment and efficient work, substantially be in ashless environment, thus the reliability in boiler and even whole power plant can be improved.
The technical scheme that the utility model is taked is:
A kind of boiler ultra low-ash back-end ductwork system, comprise economizer, denitrating system, air preheater, high-temperature dust removal system is provided with before denitrating system after economizer, denitrating system is communicated with desulphurization system by the air preheater that connects successively, flue gas waste heat recovery system, air-introduced machine, and desulphurization system is connected with chimney.
The dust content of the back-end ductwork after hot precipitator is all in reduced levels, and equipment all thereafter is all in clean environment.
Described high-temperature dust removal system adopts hot electrostatic precipitator.
Described high-temperature dust removal system adopts high-temperature ceramic materials deduster.
The pattern that described high-temperature dust removal system adopts high-temperature ceramic materials deduster and hot electrostatic precipitator to combine, hot electrostatic precipitator is elementary dedusting, and Ceramic dust collector is degree of depth dedusting.
Described flue gas heat recovery system, the finned tube of employing is spiral fin coil or H type finned tube, and heat exchanger tube spacing of fin reduces, and is generally 3-5mm, makes the coefficient of heat transfer higher.
Described spacing of fin is preferably 4mm.
The utility model changes the subversiveness of traditional boiler back end ductwork system, dust pelletizing system by traditional be positioned at air preheater after, before moving forward to denitrating system, define the low cloud of dust compression ring border of whole boiler back end ductwork, for boiler improvement, denitrating catalyst serviceability temperature can be made to broaden, and efficiency is higher, avoids catalyst poisoning; Improve the coefficient of heat transfer of air preheater and flue gas waste heat recovery system, keep from heat area ash, wearing and tearing, corrosion, can deeply reducing exhausted smoke temperature, improves the energy recovery rate of flue gas waste heat recovery system; Alleviate the wearing and tearing of air-introduced machine, reduce the power consumption of air-introduced machine; Improve the efficiency of wet desulfurization system, ensure that the recovery quality of gypsum.Therefore the utility model can improve economy and the reliability of power plant boiler, improves the efficiency of environmental protection equipment, reduces the maintenance workload of boiler tail equipment.
The utility model overcomes the deficiencies in the prior art completely, and just up hill and dale dust is reduced to the numerical value of national standard requirement in the high-temperature dust removal stage, back-end ductwork is in almost completely clean state.The utility model can reduce the equipment volume of denitrating system, air preheater, flue gas waste heat recovery system, desulphurization system etc., can the original measure removal for preventing and treating wearing and tearing, burn into dust stratification, stifled ash, reduce cost, simplify the structure, decrease space.
In addition, the structure that the utility model provides also provides possibility for improving flue other system further.Based on this structure, the denitrating system under clean environment can be built, reduce the requirement of the catalyst that denitrating system adopts, without the need to considering possibility poisoning in operation; Benitration reactor can design compact, reduces and takes up an area space, without the need to considering the clogging of reactor honeycomb; New clean environment air preheater can be built.Heat exchange corrugated plating conduit gap can be more intensive, makes the coefficient of heat transfer higher, can reduce the volume of air preheater.
Accompanying drawing explanation
Fig. 1 is the boiler flue system architecture schematic diagram of prior art;
Fig. 2 is structural representation of the present utility model;
Fig. 3 is the structural representation of flue gas waste heat recovery system in the utility model.
Wherein 1 is flue entrance, and 2 is economizer, and 3 is high-temperature dust removal system, and 4 is denitrating system, and 5 is air preheater, 6 is flue gas waste heat recovery system, and 7 is air-introduced machine, and 8 is desulphurization system, and 9 is chimney, 10 is deduster, and 61 is inlet header, and 62 is outlet header, and 63 is heat-exchanging tube bundle.
Detailed description of the invention
To illustrate below in conjunction with accompanying drawing and embodiment further illustrates the utility model:
The boiler smoke ultra low-ash back-end ductwork system that the utility model provides comprises flue entrance 1, economizer 2, high-temperature dust removal system 3, denitrating system 4, air preheater 5, flue gas waste heat recovery system 6, air-introduced machine 7, desulphurization system 8 and chimney 9, the exiting flue gas dust concentration of high-temperature dust removal system 3 meets discharging standards, such as key area, control discharge dust concentration is 20mg/Nm
3.Back-end ductwork like this after this dust pelletizing system, is all in the flue gas environment of ultra low-ash concentration, creates clean working environment for being positioned at later equipment.
Embodiment 1
Figure 2 shows that specific embodiment of the utility model, it also adopts 125MW coal-burning boiler, described boiler uses the high-temperature dust removal system 3 be arranged in before denitrating system 4 to instead of traditional electrostatic precipitator 11, the ash-laden gas that boiler furnace (not shown) is discharged enters economizer 2 through flue entrance 1, after high-temperature dust removal system 3 dedusting, enter denitrating system 4 and air preheater 5, flue gas waste heat recovery system 6, air-introduced machine 7 and desulphurization system 8 successively, eventually pass through chimney 9 and discharge.
In the present embodiment running, high-temperature dust removal system 3 adopts the hot electrostatic precipitator that can tolerate 400 DEG C of temperature, normally to operate in the high-temperature area between economizer 2 and denitrating system 4.High-temperature dust removal system 3 is hot electrostatic precipitator, comprises 5 electric fields, makes outlet dust emission concentration all the time lower than 20mg/m
3, discharge capacity is up to state standards, without the need to arranging other dust arresters at flue afterbody.High-temperature dust removal system 3 efficiency of dust collection can reach 99.8%, and not by the impact of Inlet dust concentration ratio, ratio resistance.In the present embodiment, high-temperature dust removal system 3 also can use the arrangement of 6 electric fields, with the requirement making discharge capacity reach higher standard.
In the present embodiment, dust particale in flue gas environment residing for denitrating system 4 is removed, denitrating system 4 works in clean cigarette environment, thus avoid the pollution of catalyst and poisoning, make denitration efficiency can remain on more than 90% for a long time, in simultaneously extending catalyst service life, decrease operation and maintenance cost.
The wear problem of air preheater 5 and flue gas waste heat recovery system 6 is resolved equally.
The prior minimizing due to equipment inner wall dust stratification, heat transfer effect improves.When running under operating mode at full capacity, it is even lower that the exhaust gas temperature of air preheater 5 can reach design load 130 DEG C, directly brings considerable economic benefit.The structure of flue gas waste heat recovery system 6 in the present embodiment and identical in comparative example.Because the flue gas waste heat recovery system 6 in embodiment is in clean cigarette environment, therefore there is not problem, wear problem that the dust stratification mentioned in comparative example causes overall heat exchange efficiency to decline.In the present embodiment, in rated power operation situation, the cigarette temperature of entering of flue gas waste heat recovery system 6 is 132 DEG C, and when exhaust gas temperature is 107 DEG C, the inflow temperature of flue gas waste heat recovery system 6 is 80 DEG C, and flow is 65t/h, and leaving water temperature is 100-110 DEG C.
In the present embodiment, directly discharge boiler exhaust gas system through air-introduced machine 7, desulfurizer 8 and chimney 9 by the flue gas of flue gas waste heat recovery system 6 and enter air.
Embodiment 2
The present embodiment difference compared with embodiment 1 is to use refractory ceramics deduster to instead of hot electrostatic precipitator, refractory ceramics deduster is inner primarily of porous ceramic filter pipe and structure stand composition, can run under the hot environment of the highest 1000 DEG C, variations in temperature is less on efficiency of dust collection impact, running resistance is little, and refractory ceramics deduster can make efficiency of dust collection up to more than 99.96%, than general electric cleaner height 0.1%-0.5%, and first cost is low, does not change by boiler load and affect.
In addition, the pattern that described high-temperature dust removal system of the present utility model can also adopt high-temperature ceramic materials deduster and hot electrostatic precipitator to combine, hot electrostatic precipitator is elementary dedusting, and Ceramic dust collector is degree of depth dedusting.
Embodiment 3
The present embodiment is the further improvement to embodiment 1, has mainly made transformation to the structure of flue gas waste heat recovery system 6.
Identical with embodiment 1, before the high-temperature dust removal system 3 of the present embodiment is arranged in denitrating system 4, the ash-laden gas that boiler furnace (not shown) is discharged enters economizer 2 through flue entrance 1, after high-temperature dust removal system 3 dedusting, enter denitrating system 4 and air preheater 5, flue gas waste heat recovery system 6, air-introduced machine 7 and desulphurization system 8 successively, eventually pass through chimney 9 and discharge.
Flue gas waste heat recovery system 6 in the present embodiment comprises inlet header 61, outlet header 62 and heat-exchanging tube bundle 63, and heat-exchanging tube bundle 63 is spiral fin coil, and spacing of fin is 4mm.Because the flue gas waste heat recovery system 6 in embodiment is in clean cigarette environment, therefore there is not the problem that the dust stratification mentioned in comparative example causes flue blockage, layout fin that can be more intensive in the tube bank of equal length, thus heat exchange area is increased under the prerequisite not reducing cigarette speed, improve the overall heat exchange efficiency of flue gas waste heat recovery system 6.In the present embodiment, in rated power operation situation, the cigarette temperature of entering of flue gas waste heat recovery system 6 is 132 DEG C, and when exhaust gas temperature is 105 DEG C, the inflow temperature of flue gas waste heat recovery system 6 is 80 DEG C, and flow is 65t/h, and leaving water temperature is 105-115 DEG C.
Applicant builds lab platform according to reynolds analogue criterion and measures, and calculates primary operating parameter comparable situation when flue gas waste heat recovery system 6 under identical boiler load, identical heat exchanger tube length, diameter condition adopts various heat-exchanging tube bundle in dust-laden and non-dusty circumstances:
Table 1
Known by contrasting, in identical spacing of fin situation, the heat exchanger tube heat exchange property in dustfree environment is obviously better than the heat exchanger tube in dusty circumstances.In dustfree environment, along with the reduction of spacing of fin, heat exchanger tube heat exchange property is constantly strengthened, and this is that spacing of fin is less, and heat exchange area is larger, and therefore heat exchanger tube heat exchange property is stronger due in identical heat exchanger tube length situation.Along with spacing of fin is reduced to 3mm from 4mm, the raising of heat exchanger tube heat exchange property is also not obvious, this is due to when spacing of fin reaches 3mm, the resistance of heat exchanger tube to flue gas causes cigarette speed to decline, heat exchanger tube heat exchange property is affected, therefore, even if in dustfree environment, the fin of heat exchanger tube also should be avoided to arrange too intensive.
The flue gas waste heat recovery system 6 of the present embodiment structurally difference with the prior art is mainly spacing of fin, it comprises inlet header 61, outlet header 62 and heat-exchanging tube bundle 63, heat-exchanging tube bundle 63 is spiral fin coil, and spacing of fin can be 3-5mm, preferred 4mm.Because the heat exchanger coefficient of heat transfer is improved, the heat exchange efficiency of flue gas waste heat recovery system 6 is improved significantly, and the efficiency that fume afterheat utilizes is higher, and effects of energy saving and emission reduction is better.
In addition, when adopting heat-exchanging tube bundle to adopt H type finned tube, its dust stratification and heat transfer characteristic have identical Changing Pattern with spiral fin coil, reach more excellent effect when spacing of fin 3-5mm, take 4mm as optimum.That is, in neat stress environment, the fin of H type finned tube is arranged and also than prior art more crypto set, thus can be improved the coefficient of heat transfer of heat exchanger.
The foregoing is only preferred embodiment of the present utility model; not in order to limit the utility model; all within spirit of the present utility model and principle, any amendment made, equivalent replacements, improvement etc., all should be included within scope that the utility model protects.
Claims (5)
1. a boiler ultra low-ash back-end ductwork system, comprise economizer, denitrating system, air preheater, flue gas waste heat recovery system, it is characterized in that, high-temperature dust removal system is provided with before denitrating system after economizer, denitrating system is communicated with desulphurization system by the air preheater that connects successively, flue gas waste heat recovery system, air-introduced machine, and desulphurization system is connected with chimney.
2. a kind of boiler ultra low-ash back-end ductwork system according to claim 1, it is characterized in that, described high-temperature dust removal system is hot electrostatic precipitator or refractory ceramics deduster.
3. a kind of boiler ultra low-ash back-end ductwork system according to claim 1, it is characterized in that, the pattern that described high-temperature dust removal system adopts high-temperature ceramic materials deduster and hot electrostatic precipitator to combine, hot electrostatic precipitator is elementary dedusting, and Ceramic dust collector is degree of depth dedusting.
4. a kind of boiler ultra low-ash back-end ductwork system according to claim 1, it is characterized in that, described flue gas waste heat recovery system comprises inlet header, outlet header and heat-exchanging tube bundle, and heat-exchanging tube bundle is spiral fin coil or H type finned tube, and spacing of fin is 3-5mm.
5. a kind of boiler ultra low-ash back-end ductwork system according to claim 4, it is characterized in that, described spacing of fin elects 4mm as.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520004003.2U CN204404203U (en) | 2015-01-04 | 2015-01-04 | A kind of boiler ultra low-ash back-end ductwork system |
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|---|---|---|---|
| CN201520004003.2U CN204404203U (en) | 2015-01-04 | 2015-01-04 | A kind of boiler ultra low-ash back-end ductwork system |
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| CN204404203U true CN204404203U (en) | 2015-06-17 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104534491A (en) * | 2015-01-04 | 2015-04-22 | 山东大学 | Ultralow-dust rear smoke channel system of boiler |
| CN105003926A (en) * | 2015-06-29 | 2015-10-28 | 张荣华 | Dust removal and denitration and waste heat recovery device for flue of boiler |
-
2015
- 2015-01-04 CN CN201520004003.2U patent/CN204404203U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104534491A (en) * | 2015-01-04 | 2015-04-22 | 山东大学 | Ultralow-dust rear smoke channel system of boiler |
| CN105003926A (en) * | 2015-06-29 | 2015-10-28 | 张荣华 | Dust removal and denitration and waste heat recovery device for flue of boiler |
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Granted publication date: 20150617 Termination date: 20180104 |
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