Summary of the invention
The objective of the invention is to the problems referred to above, provide a kind of thermal power plant coal-burning boiler smoke discharging residual heat to reclaim and the reduction of discharging comprehensive application system.
The object of the invention is realized through following technical proposals:
A kind of thermal power plant coal-burning boiler smoke discharging residual heat reclaims and reduces discharging comprehensive application system; It is characterized in that: along the flow direction of flue gas; Be disposed with air preheater, first low-level (stack-gas) economizer, low cold precipitator, air-introduced machine, second low-level (stack-gas) economizer, desulfurization island on the pipeline between from the boiler to the chimney; Said air preheater import is connected with a cold airduct road, cold secondary wind pipeline respectively; Said cold secondary wind pipeline is provided with the secondary wind steam air heater, and said secondary wind steam air heater is communicated with second low-level (stack-gas) economizer through the hydrophily pipeline, and said hydrophily pipeline is provided with expansion tank, water pump.
As optimal way, a said cold airduct road is provided with the wind steam air heater one time, a said wind steam air heater and the shared identical hydrophily pipeline of said secondary wind steam air heater.
As optimal way, a said cold airduct road is provided with the wind steam air heater one time, and a said wind steam air heater passes through condensing water conduit and links to each other from the low-pressure heater in the heat regenerative system, and said condensing water conduit is provided with booster.
Workflow of the present invention: flue gas comes out from air preheater; Through first low-level (stack-gas) economizer; Cigarette temperature drop to 90 ℃ about-100 ℃, low-temperature flue gas gets into the deduster dedusting, then entering second low-level (stack-gas) economizer through air-introduced machine boosts after; The cigarette temperature drop allows inlet temperature to desulfurization, and flue gas is after desulfurization island, chimney enter atmosphere.First low-level (stack-gas) economizer is used for heat-setting water, and second low-level (stack-gas) economizer is through the be situated between cold secondary wind of heating air preheater import of the hydrophily on the hydrophily pipeline.Cold wind mode of heating according to the air preheater import is different; Comprise three schemes:
the cold wind of air preheater import do not heat, the cold elegance of
air preheater import is used the heating source identical with cold secondary wind; The cold elegance of
air preheater import is with independent condensate heating; This condensate is from heat regenerative system certain one-level low-pressure heater wherein, with condensate in first low-level (stack-gas) economizer be not from the one-level low-pressure heater.
The effect of (1) first low-level (stack-gas) economizer is following:
First low-level (stack-gas) economizer utilizes fume afterheat heat-setting water, can reduce the unit hear rate, reduces the coal consumption of unit generation mark.On the other hand; Flue gas is behind first low-level (stack-gas) economizer, and the cigarette temperature significantly reduces, and the flue gas volume flow in deduster and downstream significantly reduces; This not only can reduce specification capacity such as deduster, air-introduced machine, flue, and helps reducing the energy consumption of deduster, air-introduced machine; Simultaneously, the cigarette temperature drop is low, can change the exhaust gas dust characteristic, and it is favourable that electric cleaner is gathered dust.
Before first low-level (stack-gas) economizer is arranged in deduster, be in the high ash-laden gas environment, therefore exit gas temperature, should take measures to prevent the first low-level (stack-gas) economizer dust stratification, corrosion and wearing and tearing from aspects such as material, technology, designs near the flue gas dew point temperature.
The effect of (2) second low-level (stack-gas) economizers is following:
The many synchronized desulfurings of domestic large-scale unit, denitration at present, part is provided with low-level (stack-gas) economizer, makes that air-introduced machine shaft power is big, and flue gas temperature rise behind air-introduced machine is higher.For 1000MW level unit exhaust gas volumn, when the air-introduced machine voltage rise reaches about 8500Pa, the cigarette temperature will raise about 10 ℃.In order effectively to utilize air-introduced machine temperature rise heat, second low-level (stack-gas) economizer is set.
Second low-level (stack-gas) economizer utilizes fume afterheat, is situated between through the hydrophily on the hydrophily pipeline and heats the cold secondary wind and/or a cold wind of air preheater import, improves the air preheater EAT.On the hydrophily pipeline expansion tank is set and booster provides hydrophily.For wet desulphurization, flue gas gets into desulfurization island behind second low-level (stack-gas) economizer, considers water balance in the desulfurization island, and flue-gas temperature is taken as desulfurization and allows inlet temperature behind second low-level (stack-gas) economizer.For wet desulphurization, main water consumption is that will spray water evaporates used up owing to get into the hot flue gas of desulfurization island, second low-level (stack-gas) economizer is set after, the reduction of desulfurization island inlet flue gas temperature can be practiced thrift the desulphurization system water consumption.
(3) effect of low cold precipitator is following:
Flue gas is after the cooling of first low-level (stack-gas) economizer, and the electric cleaner entrance flue gas temperature is lower, is near or below the flue gas dew point temperature, and performance of precipitator improves, and this electric cleaner is called low cold precipitator.
The electric cleaner inlet flue gas temperature of the present extensive use of China is many about 120 ℃, and then about 90-100 ℃, the cigarette temperature descends more low cold precipitator inlet flue gas temperature.Compare with conventional electric cleaner, adopt low cold precipitator to mainly contain following benefit;
1) the cigarette temperature drop is low, and the flue gas volume flow reduces, and the flow velocity of flue gas is also corresponding to be reduced, and the time of staying will increase in deduster, and electric dust collector can effectively be caught flue dust.10 ℃ of the every reductions of flue-gas temperature, exhaust gas volumn will reduce about 6%.
2) the low optimum efficiency interval that can reduce dust specific resistance to electric precipitation of cigarette temperature drop.Rule of thumb, about the cigarette temperature is from 130 ℃, drop to about 90 ℃, dust specific resistance can reduce an one magnitude.In the high specific resistance zone, lower more than resistance, efficiency of dust collection is high more.
3) the cigarette temperature drop is low, and deduster electric field breakdown voltage is improved, and this is favourable to improving efficiency of dust collection.About 10 ℃ of the every reduction of cigarette temperature, electric field breakdown voltage raises about 3%.
4) can remove most SO
3, reduce the tail flue gas cold end corrosion.Because flue-gas temperature has dropped to below the dew-point temperature, dust contained flue gas concentration is higher, and total surface area is very big, adheres to the condition that provides good for condensing of sulfuric acid mist.Generally, grey sulphur compared greater than 100 o'clock, the SO in the flue gas
3Clearance can reach more than 95%, and this helps to reduce the cold end corrosion of deduster rear pass, blower fan.
5) efficiency of dust collection is high, and dust emission concentration can reach 20-30mg/Nm
3Or it is lower.When the deduster inlet flue gas temperature is 99 ℃, during the low cold precipitator of the two chambers of configuration biserial four electric fields, dust concentration will on average be lower than 20mg/Nm
3When the deduster inlet temperature is 93 ℃, during the low cold precipitator of the two chambers of configuration biserial four electric fields, the smoke dust discharge concentration minimum is merely 7 mg/Nm
3
This shows that low cold precipitator can improve efficiency of dust collection, in design, can adopt less deduster specification, less service area, less number of power sources, lower power consumption, small device floor space etc.
(4) effect of steam air heater is following
For preventing cold end corrosion of air preheater cold junction and stifled ash, and adopt steam air heater or flue gas recirculation, steam air heater generally adopts Steam Heating.
Among the application, the secondary wind steam air heater adopts hydrophily Jie to absorb the second low-level (stack-gas) economizer flue gas and reclaims heat, improves the air preheater inlet temperature.It is estimated, when the second low-level (stack-gas) economizer flue gas temperature drop is 18 ℃, can second wind cooling wind-warm syndrome degree be improved about 30 ℃.Wind steam air heater adopt the thermal source identical with the secondary wind steam air heater or adopt independent condensate heat (with condensate in first low-level (stack-gas) economizer be not from the one-level low-pressure heater; Need according to the heating-up temperature requirement; Select suitable condensate to pick out a little and the backwater point), condensate line need be provided with booster and be used to boost.
Adopt the condensate among the application to compare with conventional steam steam air heater with hydrophily Jie (from the fume afterheat of second low-level (stack-gas) economizer) steam air heater, the pipe specification can reduce, and can high-quality steam is used for generating electricity, and improves the unit hear rate, reduces the unit net coal consumption rate.Compare with flue gas recirculation, can reduce the pressure fan volume flow, reduce the pressure fan energy consumption.
Steam air heater is set; Improve air preheater inlet wind-warm syndrome as far as possible; Not only can reduce the air preheater cold end corrosion, the more important thing is, air preheater inlet wind-warm syndrome raises; Boiler air preheater outlet exhaust gas temperature can raise, and is that first low-level (stack-gas) economizer reclaims more thickness gas waste heat and created condition.Estimate that according to the boiler factory when 10 ℃ of air preheater inlet wind-warm syndrome risings, the flue gas exhaust gas temperature can raise about 6-7 ℃.
When the cold elegance on the air preheater during with the heating of independent condensate, this condensate is from heat regenerative system one-level low-pressure heater, with condensate in first low-level (stack-gas) economizer be not from the one-level low-pressure heater.
Beneficial effect of the present invention: the application is provided with the low-level (stack-gas) economizer segmentation, and one section is arranged between air preheater and the deduster, is used for heat-setting water; One section is arranged between air-introduced machine and the desulfurization island; Through the cold secondary wind of hydrophily Jie heating air preheater import,, three kinds of embodiments are arranged according to the difference of the cold wind mode of heating of air preheater import; Because the deduster inlet flue gas temperature is lower; Can reduce flue gas volume, reduce dust specific resistance, thereby performance of precipitator is improved, dust emission concentration can be reduced to 20~30mg/Nm
3, the cold secondary wind of air preheater import is utilized the fume afterheat heating, and a cold wind of air preheater import is through the condensate heating; The application's maximizing utilizes fume afterheat, not only can reduce the unit hear rate, reduces the unit net coal consumption rate; Also can reduce equipment energy consumptions such as deduster, air-introduced machine, pressure fan, reduce station service power consumption rate, improve the economy of power plant; Energy efficient helps the construction of low-carbon (LC) society more efficiently.
The specific embodiment
Below in conjunction with specific embodiment and accompanying drawing the present invention is further described.
Whether the cold wind according to the air preheater import heats and the mode of heating difference, is divided into following three embodiment.
Embodiment 1
As shown in Figure 2; A kind of thermal power plant coal-burning boiler smoke discharging residual heat reclaims and reduces discharging comprehensive application system; The flow direction along flue gas; On the pipeline between 7 from the boiler to the chimney, be disposed with air preheater 1, first low-level (stack-gas) economizer 2, low cold precipitator 3, air-introduced machine 4, second low-level (stack-gas) economizer 5, desulfurization island 6, said air preheater 1 import is connected with a cold airduct road 15, cold secondary wind pipeline 16 respectively, and said cold secondary wind pipeline 16 is provided with secondary wind steam air heater 9; Said secondary wind steam air heater 9 is communicated with second low-level (stack-gas) economizer 5 through hydrophily pipeline 10, and said hydrophily pipeline 10 is provided with expansion tank 11, water pump 12.There is not heater on the said cold airduct road 15.
The workflow of present embodiment: flue gas C comes out from air preheater; Through first low-level (stack-gas) economizer; Cigarette temperature drop to 90 ℃ about-100 ℃, low-temperature flue gas gets into the deduster dedusting, then entering second low-level (stack-gas) economizer through air-introduced machine boosts after; The cigarette temperature drop allows inlet temperature to desulfurization, and flue gas is after desulfurization island, chimney enter atmosphere.First low-level (stack-gas) economizer is used for heat-setting water, and second low-level (stack-gas) economizer is through the be situated between cold secondary wind B of heating air preheater import of the hydrophily on the hydrophily pipeline.
Embodiment 2
As shown in Figure 3; A kind of thermal power plant coal-burning boiler smoke discharging residual heat reclaims and reduces discharging comprehensive application system; The flow direction along flue gas; On the pipeline between 7 from the boiler to the chimney, be disposed with air preheater 1, first low-level (stack-gas) economizer 2, low cold precipitator 3, air-introduced machine 4, second low-level (stack-gas) economizer 5, desulfurization island 6, said air preheater 1 import is connected with a cold airduct road 15, cold secondary wind pipeline 16 respectively, and said cold secondary wind pipeline 16 is provided with secondary wind steam air heater 9; Said secondary wind steam air heater 9 is communicated with second low-level (stack-gas) economizer 5 through hydrophily pipeline 10, and said hydrophily pipeline 10 is provided with expansion tank 11, water pump 12.A said cold airduct road 15 is provided with wind steam air heater 8 one time, a said wind steam air heater 8 and said secondary wind steam air heater 9 shared identical hydrophily pipelines 10.
The workflow of present embodiment: flue gas C comes out from air preheater; Through first low-level (stack-gas) economizer; Cigarette temperature drop to 90 ℃ about-100 ℃, low-temperature flue gas gets into the deduster dedusting, then entering second low-level (stack-gas) economizer through air-introduced machine boosts after; The cigarette temperature drop allows inlet temperature to desulfurization, and flue gas is after desulfurization island, chimney enter atmosphere.
In the present embodiment; The cold wind A of air preheater import adopts the heating source identical with cold secondary wind B; Promptly a wind steam air heater 8 is communicated with common hydrophily pipeline 10 with secondary wind steam air heater 9, and the hydrophily that is provided by water pump 12 and expansion tank 11 on the hydrophily pipeline 10 is situated between, and is used to the fume afterheat from second low-level (stack-gas) economizer; The cold secondary wind and a cold wind of the import of heating air preheater improve the air preheater EAT.
Embodiment 3
As shown in Figure 4; A kind of thermal power plant coal-burning boiler smoke discharging residual heat reclaims and reduces discharging comprehensive application system; The flow direction along flue gas; On the pipeline between 7 from the boiler to the chimney, be disposed with air preheater 1, first low-level (stack-gas) economizer 2, low cold precipitator 3, air-introduced machine 4, second low-level (stack-gas) economizer 5, desulfurization island 6, said air preheater 1 import is connected with a cold airduct road 15, cold secondary wind pipeline 16 respectively, and said cold secondary wind pipeline 16 is provided with secondary wind steam air heater 9; Said secondary wind steam air heater 9 is communicated with second low-level (stack-gas) economizer 5 through hydrophily pipeline 10, and said hydrophily pipeline 10 is provided with expansion tank 11, water pump 12.
A said cold airduct road 15 is provided with wind steam air heater 8 one time, and a said wind steam air heater 8 passes through condensing water conduit 13 and links to each other from the low-pressure heater in the heat regenerative system, and said condensing water conduit 13 is provided with booster 14.
Workflow of the present invention: flue gas C comes out from air preheater; Through first low-level (stack-gas) economizer; Cigarette temperature drop to 90 ℃ about-100 ℃, low-temperature flue gas gets into the deduster dedusting, then entering second low-level (stack-gas) economizer through air-introduced machine boosts after; The cigarette temperature drop allows inlet temperature to desulfurization, and flue gas is after desulfurization island, chimney enter atmosphere.First low-level (stack-gas) economizer is used for heat-setting water, and second low-level (stack-gas) economizer is through the be situated between cold secondary wind B of heating air preheater import of the hydrophily on the hydrophily pipeline.The cold wind A of air preheater import adopts independent condensate G heating; This condensate is from heat regenerative system certain one-level low-pressure heater wherein; With condensate F in first low-level (stack-gas) economizer be not from the one-level low-pressure heater; Need to select suitable condensate to pick out a little and the backwater point according to the heating-up temperature requirement, condensate line need be provided with booster and be used to boost.
The above is merely preferred embodiment of the present invention, not in order to restriction the present invention, all any modifications of within spirit of the present invention and principle, being done, is equal to and replaces and improvement etc., all should be included within protection scope of the present invention.