CN203595114U - Natural circulation drum boiler with smoke warning system - Google Patents

Natural circulation drum boiler with smoke warning system Download PDF

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Publication number
CN203595114U
CN203595114U CN201320448193.8U CN201320448193U CN203595114U CN 203595114 U CN203595114 U CN 203595114U CN 201320448193 U CN201320448193 U CN 201320448193U CN 203595114 U CN203595114 U CN 203595114U
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China
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boiler
economizer
drum
flue gas
temperature
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CN201320448193.8U
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王东平
谭青
张彦琦
王伟敏
王吉翔
章良
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SHANGHAI ELECTRIC POWER ENGINEERING Co Ltd
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SHANGHAI ELECTRIC POWER ENGINEERING Co Ltd
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Priority to CN201320186122.5 priority
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Priority to CN201320448193.8U priority patent/CN203595114U/en
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Abstract

The utility model relates to a natural circulation drum boiler with a smoke warning system, which comprises a boiler, a steam drum, an economizer, a SCR reactor, an air pre-heater and a smoke warming system, wherein a down pipe of the steam drum is connected to a down water drum of the boiler, the smoke warming system comprises a water pump, a switch valve and an electric control valve, wherein the down water drum of the boiler is connected to an inlet pipeline of the water pump by the switch valve and an outlet pipeline of the water pump is connected in parallel with a water feeding inlet pipeline of the economizer by the electric control valve. A check valve is connected between the outlet of the water pump and the electric control valve. The forced natural drum boiler with the smoke warming system in the utility model is applicable to the subcritical and ultrahigh-pressure forced natural drum boiler and can realize normal operation of the SCR reactor under conditions of low loads and/or low atmospheric temperatures, so that smoke discharge quality of the subcritical and ultrahigh-pressure forced natural drum boiler under the conditions of low loads and/or low atmospheric temperatures can be ensured to reach national standards as well.

Description

With the Natural Circulation dum boiler of flue gas temperature elevation system
Technical field
The utility model relates to a kind of Natural Circulation dum boiler of the use of generating electricity, especially a kind of Natural Circulation dum boiler of the SCR reactor inlet cigarette temperature that can improve Natural Circulation dum boiler.
Background technology
The energy resource structure of China is take coal as main, and coal consumption amount is also by sustainable growth.According to statistics, the installed capacity of current Chinese capacity of installed generator moderate heat electricity accounts for more than 74%, and in following a very long time, the coal-fired nitrogen oxides pollution causing is the another important environmental problem after sulfur dioxide pollution." fossil-fuel power plant atmospheric pollutant emission standard (GB13223-2011) " that implement in January, 2011 is reduced to 100 ~ 200mg/m the highest permission concentration of emission of station boiler nitrogen oxide limit value simultaneously 3, coal-fired electric generation furnace configuration SCR reactor is realized denitrating flue gas has become a kind of standard configuration.Along with economical and social development, will be strict gradually to the concentration of emission of SCR reactor denitrification apparatus and the rate requirement that comes into operation.
Nitrogen oxide refers generally to NO, NO 2, NO 3, N 2o, N 2o 3deng, be referred to as NO x.The nitrogen oxide generating in boiler combustion process (is mainly NO and NO 2) seriously pollute environment.Therefore suppress NO xgeneration and remove the NO having generated in flue gas xone of the subject matter that must consider when oneself becomes boiler combustion design and operation.
Selective catalytic reduction (SCR) is most widely used, and the denitration method for flue gas of technology maturation, and oneself becomes the mainstream technology of current station boiler denitration.SCR denitration efficiency is high, and concentration of emission is low can be met at present and strict environmental requirement from now on, is day by day subject to China and the attention of other country in the world.
At present commercial more widely SCR reactor denitration temperature general control at 320 ~ 400 ℃.When the temperature of SCR reactor inlet flue gas is during lower than 300 ℃, can make the activity decreased of SCR catalyst reactor, cannot realize the normal operation of SCR reactor denitration.Therefore the temperature that, guarantees suitable SCR reactor denitration inlet flue gas is the key of the normal operation of SCR reactor denitration.
The flow process (Fig. 1) of existing boiler water side is: feedwater enters drum 6 after economizer 7 heats up.The saturation water of the bottom of drum 6 enters the lower water bag 10 of boiler through down-comer 5, the water of lower water bag 10 is by water-cooling wall 9 rising draw heats, thereby part is evaporated to steam, and steam water interface enters drum 6 and completes carbonated drink separation.Saturated vapor after separation enters superheater, and saturation water enters down-comer 5 and continues circulation.
The structural representation of subcritical 300MW Natural Circulation dum boiler as shown in Figure 4, comprises boiler 4, drum 6, economizer 7, SCR reactor, air preheater, and the down-comer 5 of drum 6 is connected with the lower water bag 10 of boiler 4.
The current reason due to Natural Circulation dum boiler design aspect, when Natural Circulation dum boiler moves under underload and/or atmospheric temperature low condition, the SCR reactor smoke inlet temperature of the Natural Circulation dum boiler of subcritical and super-pressure differs and can reach more than 20 ℃ with the temperature that can guarantee the normal operation of SCR reactor, therefore under underload and/or atmospheric temperature low condition, SCR reactor cannot put into operation, and smoke emissioning concentration can not meet China national environmental requirement.
Summary of the invention
The utility model is in order to solve the Natural Circulation dum boiler technical problem that SCR reactor cannot put into operation under underload and/or atmospheric temperature low condition, and provide a kind of Natural Circulation dum boiler with flue gas temperature elevation system, by the water system of existing Natural Circulation dum boiler is transformed, utilizing water pump that the high temperature saturation water that is entered the lower water bag of boiler by the down-comer of drum is delivered to the side-entrance of boiler economizer water mixes with economizer feedwater, to improve the feed temperature of economizer, and then raising boiler economizer exit gas temperature, make it temperature and reach the Applicable temperature that SCR reactor puts into operation.
For achieving the above object, the technical solution of the utility model: a kind of Natural Circulation dum boiler with flue gas temperature elevation system, comprise boiler, drum, economizer, SCR reactor, air preheater, flue gas temperature elevation system, the down-comer of drum is connected with the lower water bag of boiler, it is characterized in that: described flue gas temperature elevation system is made up of water pump, switch valve, electric control valve; The lower water bag of boiler is connected with pump entrance pipeline by switch valve, and the outlet conduit of water pump is connected in parallel by the feed-water intake pipeline of electric control valve and economizer.
Between water delivery side of pump and electric control valve, be connected with check-valves.
In a preferred embodiment of the present utility model, between water delivery side of pump and electric control valve, check-valves is installed, thereby is avoided entering the aqueous reflux in economizer, thereby guarantee the safe operation in boiler of flue gas temperature elevation system.
With the schematic flow sheet of the water side of the dum boiler of flue gas temperature elevation system as shown in Figure 2, the saturation water of drum bottom i.e. isolating door 1 in figure of switch valve successively after the lower water bag of boiler, water pump, electric control valve i.e. adjustment doors 3 in figure regulates and enters economizer, enter the mixing of this part saturation water of economizer and the feedwater of economizer, improve the temperature of economizer entrance feedwater, thereby reduce the temperature difference of water and flue gas in economizer, cause the minimizing of flue gas thermal discharge, the temperature of economizer exit flue gas has had raising to a certain degree, thereby make the temperature of the flue gas that enters SCR reactor can meet the Applicable temperature that SCR reactor puts into operation.
A kind of Natural Circulation dum boiler with flue gas temperature elevation system of the present utility model, is applicable to subcritical and dum boiler super-pressure.
The beneficial effects of the utility model are:
The utility model is by increasing water pump, switch valve, electric control valve and corresponding pipeline, the fractional saturation water of discharging from drum is mixed with the feedwater that enters economizer after water bag boiler, thereby improve the temperature of economizer entrance feedwater, reduce the temperature difference of water and flue gas in economizer, make the minimizing of flue gas thermal discharge, the temperature of economizer exit flue gas is improved, the flue-gas temperature that makes to enter SCR reactor can meet the Applicable temperature putting into operation of SCR reactor, therefore, by increasing flue gas temperature elevation system, guarantee SCR reactor normally operation under underload and/or atmospheric temperature low condition of the dum boiler of former Natural Circulation, thereby guarantee that the Natural Circulation dum boiler fume emission quality under the subcritical and super-pressure under underload and/or atmospheric temperature low condition also can be up to state standards.
Further, between water delivery side of pump and electric control valve, check-valves is installed, thereby is avoided entering the aqueous reflux in economizer, thereby guarantee the safe operation in boiler of flue gas temperature elevation system.
Further, of the present utility modelly transform by water side, effectively solve the problem that SCR reactor inlet cigarette temperature SCR reactor low and that cause is stopped transport under underload and/or atmospheric temperature low condition, there is the amplitude of lifting flue-gas temperature large compared with other method of water side, and system is simple, investment for trnasforming urban land is few, and other operating mode is affected to little feature.Further comparing maximum feature of the present utility model with fume side remodeling method is that the reconstruction scope is little, small investment, and the construction time is short.
Further, at present more conventional economizer classification raising cigarette temperature method of the present utility model at least can be saved investment cost over half.
Accompanying drawing explanation
Fig. 1 is the schematic diagram of the former water effluent of existing Natural Circulation dum boiler journey;
Fig. 2 is the Natural Circulation dum boiler structural representation with flue gas temperature elevation system of the present utility model;
Fig. 3 is the graph of a relation of the situation that puts into operation of SCR reactor of subcritical 300MW Natural Circulation dum boiler and unit load, ambient temperature;
Fig. 4 is the structural representation of existing subcritical 300MW Natural Circulation dum boiler;
Fig. 5 is the structural representation of the subcritical 300MW Natural Circulation dum boiler with flue gas temperature elevation system of the present utility model.
The specific embodiment
Also by reference to the accompanying drawings the utility model is further set forth below by concrete Application Example, but do not limit the utility model.
As shown in Figure 2, the Natural Circulation dum boiler with flue gas temperature elevation system of the present utility model, comprises boiler 4, drum 6, economizer 7, SCR reactor, air preheater, flue gas temperature elevation system etc.
The down-comer 5 of drum 6 is connected with lower water bag 10 imports of boiler 4, and lower water contracts out mouth and connects drum 6 by the water-cooling wall 9 in boiler 4 burner hearths.Flue gas temperature elevation system is made up of water pump 3, switch valve 1, electric control valve 2; The lower water bag 10 of boiler 4 is connected with water pump 3 inlet ducts by switch valve 1, and the outlet conduit of water pump 3 is connected in parallel by electric control valve 2 and the feed-water intake pipeline 8 of economizer 7.
As shown in Figure 5, in a preferred embodiment of the present utility model, between the outlet of water pump 3 and electric control valve 2, check-valves 11 is installed, thereby is avoided entering the aqueous reflux in economizer, thereby guarantee the safe operation in boiler of flue gas temperature elevation system.
The saturation water of drum 6 bottoms after the lower water bag 10 of boiler 4 successively through switch valve 1, water pump 3, after regulating, electric control valve 2 enters economizer 7, enter the mixing of this part saturation water of economizer 7 and the feedwater of economizer 7, improve the temperature of economizer 7 entrance feedwater, thereby reduce the temperature difference of water and flue gas in economizer 7, cause the minimizing of flue gas thermal discharge, the temperature that economizer 7 exports flue gas has had raising to a certain degree, thereby makes the temperature of the flue gas that enters SCR reactor can meet the Applicable temperature that SCR reactor puts into operation.
Natural Circulation dum boiler with flue gas temperature elevation system of the present utility model, is applicable to subcritical and dum boiler super-pressure.
The utility model is by increasing in existing Natural Circulation dum boiler transformation, the saturation water that can realize drum bottom enters economizer after the lower water bag of boiler, the feedwater of this part saturation water and economizer mixes, improve economizer entrance feed temperature, thereby the temperature difference of water and flue gas in minimizing economizer, flue gas thermal discharge is reduced, further make the temperature of economizer exit flue gas improve, the entrance flue gas temperature that enters SCR reactor also raises, the saturated water amount that enters economizer entrance by adjusting is adjusted the temperature that economizer entrance feeds water, the step of going forward side by side saves the flue-gas temperature of SCR reactor inlet, make it to reach the put into operation temperature of required flue gas of SCR reactor.
With the Natural Circulation dum boiler with flue gas temperature elevation system, be introduced as an example of subcritical 300MW dum boiler example below.
One, take the subcritical 300MW Natural Circulation dum boiler of certain power plant as example, this subcritical 300MW Natural Circulation dum boiler technical parameter is as follows:
Superheated steam (MCR); Reheated steam (MCR);
Flow 1025 t/h; Flow 830t/h;
Pressure 18.3 Mpa; Pressure 3.85/3.66Mpa;
541 ℃ of temperature; 323/541 ℃ of temperature.
SCR reactor moves the requirement for smoke inlet temperature:
Inlet temperature≤314 ℃ warning;
308 ℃ of time delay 1h of 314 ℃ of < inlet temperature > stop spraying ammonia;
Inlet temperature≤308 ℃ stop spraying ammonia SCR and stop transport.
Unit load size affects boiler economizer outlet cigarette temperature, directly affects SCR reactor inlet flue-gas temperature.Outer atmospheric temperature and this power plant load affect the operational percentage of SCR reactor denitration.Ambient temperature is lower, and putting into operation of SCR reactor will be at boiler high-load region.
SCR reactor put into operation situation and unit load, ambient temperature relation as shown in Figure 3, as can be seen from Figure 3:
When ambient temperature is lower, unit is in the time of high load capacity, and SCR reactor just can put into operation.For example, ambient temperature is in the time of 10 ℃, and unit is below 190MW load, and economizer exhaust cigarette temperature just can not reach the SCR reactor condition that puts into operation;
In the time that ambient temperature raises, for example, ambient temperature is in the time of 35 ℃, and unit is more than 140MW load, and economizer exhaust cigarette temperature can reach the SCR reactor condition that puts into operation.
In a word, unit is below 140MW load time, and economizer exhaust gas temperature cannot meet the SCR reactor condition that puts into operation.
Two, subcritical 300MW Natural Circulation dum boiler original system and operating mode
The structural representation of subcritical 300MW Natural Circulation dum boiler as shown in Figure 4, comprises boiler 4, drum 6, economizer 7, SCR reactor, air preheater, and the down-comer 5 of drum 6 is connected with the lower water bag 10 of boiler 4.
When unit is when 35% rated load (136MW), its system operational parameters as shown in Figure 4.In boiler 35% rated load (136MW), boiler fuel flow 650t/h, economizer feedwater flow 365.5t/h, 396 ℃ of economizer gas approach temperature, 224.7 ℃ of economizer feed-water inlet temperature, economizer is to 265 ℃ of water outlet temperatures.Now, 290 ℃ of economizer exhanst gas outlet temperature, 314 ℃ of the minimum temperatures putting into operation lower than SCR reactor.Therefore, must improve boiler economizer outlet cigarette temperature, thereby improve SCR reactor inlet temperature, meet 314 ℃ of the minimum temperatures that SCR reactor puts into operation, thereby SCR reactor is put into operation.
Three, with the subcritical 300MW Natural Circulation dum boiler of flue gas temperature elevation system, put into operation to realize SCR reactor under the condition of underload.
With the structural representation of the subcritical 300MW Natural Circulation dum boiler of flue gas temperature elevation system as shown in Figure 5, comprise boiler 4, drum 6, economizer 7, SCR reactor, air preheater, also comprise flue gas temperature elevation system, flue gas temperature elevation system comprises water pump 3, switch valve 1, check-valves 11, electric control valve 2;
The down-comer 5 of drum 6 is connected with the lower water bag 10 of boiler 4, and the lower water bag 10 of boiler 4 is connected with water pump 3 inlet ducts through switch valve 1, and the outlet conduit of water pump 3 is in parallel with the feed-water intake pipeline 8 of economizer 7 after check-valves 11, electric control valve 3 successively.
Four, with the subcritical 300MW Natural Circulation dum boiler operation of flue gas temperature elevation system, its operational factor as shown in Figure 5:
When the subcritical 300MW Natural Circulation dum boiler load with flue gas temperature elevation system drops to a certain degree, economizer exit flue-gas temperature is during lower than the minimum applicable temperature of SCR reactor inlet, for preventing that SCR reactor from stopping transport, need to start flue gas temperature elevation system:
First opening switch valve 1, check-valves 11, water pump 3 puts into operation, then according to economizer 7 entrance feed temperatures, adjusts electric control valve 2 apertures that water pump 3 exports.Thereby adjust economizer 7 and export cigarette temperature, reach 315 ℃ when economizer 7 exports cigarette temperature, stop adjusting the aperture of electric control valve 2, at this moment, the entrance flue gas temperature that enters SCR reactor meets the flue-gas temperature that SCR reactor puts into operation, and SCR reactor can move.
When the subcritical 300MW Natural Circulation dum boiler load with flue gas temperature elevation system raises, when economizer 7 exports cigarette temperature and reaches SCR reactor service condition, close flue gas temperature elevation system, do not affect the normal operation of original subcritical 300MW Natural Circulation dum boiler.
Above said content is only the basic explanation under the utility model design, and any equivalent transformation doing according to the technical solution of the utility model all should belong to protection domain of the present utility model.

Claims (2)

1. the Natural Circulation dum boiler with flue gas temperature elevation system, comprise boiler (4), drum (6), economizer (7), SCR reactor, air preheater, flue gas temperature elevation system, the down-comer (5) of drum (6) is connected with the Xia Shuibao (10) of boiler (4), it is characterized in that: described flue gas temperature elevation system is made up of water pump (3), switch valve (1), electric control valve (2); The Xia Shuibao (10) of boiler (4) is connected with water pump (3) inlet duct by switch valve (1), and the outlet conduit of water pump (3) is connected in parallel by electric control valve (2) and the feed-water intake pipeline (8) of economizer (7).
2. the Natural Circulation dum boiler with flue gas temperature elevation system according to claim 1, is characterized in that: between the outlet of described water pump (3) and electric control valve (2), be connected with check-valves (11).
CN201320448193.8U 2013-04-15 2013-07-26 Natural circulation drum boiler with smoke warning system Active CN203595114U (en)

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Application Number Priority Date Filing Date Title
CN201320186122 2013-04-15
CN201320186122.5 2013-04-15
CN201320448193.8U CN203595114U (en) 2013-04-15 2013-07-26 Natural circulation drum boiler with smoke warning system

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Application Number Priority Date Filing Date Title
CN201320448193.8U CN203595114U (en) 2013-04-15 2013-07-26 Natural circulation drum boiler with smoke warning system

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103343959A (en) * 2013-04-15 2013-10-09 上海上电电力工程有限公司 Natural circulating drum boiler with smoke temperature rising system
CN107376635A (en) * 2016-08-18 2017-11-24 天津大唐国际盘山发电有限责任公司 A kind of anti-cold operation automatic protecting method of catalyst for denitrating flue gas and control system

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103343959A (en) * 2013-04-15 2013-10-09 上海上电电力工程有限公司 Natural circulating drum boiler with smoke temperature rising system
CN107376635A (en) * 2016-08-18 2017-11-24 天津大唐国际盘山发电有限责任公司 A kind of anti-cold operation automatic protecting method of catalyst for denitrating flue gas and control system
CN107376635B (en) * 2016-08-18 2020-02-11 天津大唐国际盘山发电有限责任公司 Automatic protection method and control system for preventing low-temperature operation of flue gas denitration catalyst

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