CN103196133A - Forced-circulation drum boiler with flue heating system - Google Patents

Forced-circulation drum boiler with flue heating system Download PDF

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Publication number
CN103196133A
CN103196133A CN 201310128405 CN201310128405A CN103196133A CN 103196133 A CN103196133 A CN 103196133A CN 201310128405 CN201310128405 CN 201310128405 CN 201310128405 A CN201310128405 A CN 201310128405A CN 103196133 A CN103196133 A CN 103196133A
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CN
China
Prior art keywords
boiler
economizer
temperature
flue gas
forced
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Pending
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CN 201310128405
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Chinese (zh)
Inventor
王东平
谭青
张彦琦
王伟敏
王吉翔
章良
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SHANGHAI ELECTRIC POWER ENGINEERING Co Ltd
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SHANGHAI ELECTRIC POWER ENGINEERING Co Ltd
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Priority to CN 201310128405 priority Critical patent/CN103196133A/en
Publication of CN103196133A publication Critical patent/CN103196133A/en
Pending legal-status Critical Current

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Abstract

The invention discloses a forced-circulation drum boiler with a flue heating system. The forced-circulation drum boiler comprises a boiler, a drum, a boiler water pump, a coal economizer, an SCR (selective catalytic reduction) reactor, an air pre-heater and the flue heating system. The flue heating system comprises electric adjusting valves 1 and 2. An inlet of the boiler water pump is connected with a downcomer of the drum, an outlet of the boiler water pump is divided into two branches, one branch is connected with a water feed bag of the boiler through the electric adjusting valve 1, and the other branch is connected with a water feed inlet pipeline of the coal economizer through the electric adjusting valve 2. The forced-circulation drum boiler with the flue heating system is applicable to subcritical and ultrahigh-pressure forced-circulation drum boilers, allows the SCR reactor to normally operate under the condition of low load and/or low atmospheric temperature, and guarantees that flue discharge quality of the subcritical and ultrahigh-pressure forced-circulation drum boilers can reach national standards under the conditions of low load and/or atmospheric temperature.

Description

A kind of forced circulation dum boiler that has the flue gas temperature elevation system
Technical field
The present invention relates to a kind of forced circulation dum boiler that has the flue gas temperature elevation system, improve the SCR reactor inlet cigarette temperature of former forced circulation dum boiler by the operation of flue gas temperature elevation system, needs improve the needs of flue-gas temperature when causing under boiler at low load and/or the atmospheric temperature low condition to satisfy that SCR reactor inlet flue-gas temperature is low can't to come into operation forced circulation dum boiler denitrating system.
Background technology
The energy resource structure of China is based on coal, and the coal consumption amount is also with sustainable growth.According to statistics, China's capacity of installed generator moderate heat Denso machine capacity accounts for more than 74% at present, and in a very long time in future, the coal-fired nitrogen oxides pollution that causes is the another important environmental problem after sulfur dioxide pollution." thermal power plant's atmosphere pollutants emission standards (GB13223-2011) " that implements in January, 2011 is reduced to 100 ~ 200mg/m to the highest permission concentration of emission of station boiler nitrogen oxide limit value simultaneously 3, coal-fired electric generation furnace configuration SCR reactor realizes that denitrating flue gas has become a kind of standard configuration.Along with development economic and society, 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 xThe nitrogen oxide that generates in the boiler combustion process (is mainly NO and NO 2) seriously polluted environment.Therefore suppress NO xGeneration and remove the NO that in flue gas, has generated xOne of subject matter that oneself must consider when becoming boiler combustion design and operation.
(SCR) is most widely used for selective catalytic reduction, and the denitration method for flue gas of technology maturation, and oneself becomes the mainstream technology of present station boiler denitration.SCR denitration efficiency height, concentration of emission is low can be satisfied at present and the environmental requirement of strictness from now on, is subjected to China and the attention of other country in the world day by day.
Present commercial SCR reactor denitration temperature is more widely generally controlled at 320 ~ 400 ℃.When the temperature of SCR reactor inlet flue gas is lower than 300 ℃, the activity of SCR catalyst reactor is reduced, can't 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.
At present, the reason of forced circulation dum boiler design aspect, when the forced circulation dum boiler moves under underload and/or atmospheric temperature low condition, the SCR reactor smoke inlet temperature of the forced circulation dum boiler of subcritical and super-pressure differs with the temperature that can guarantee the normal operation of SCR reactor and can reach more than 20 ℃, therefore under underload and/or atmospheric temperature low condition, the SCR reactor can't put into operation, and smoke emissioning concentration can not satisfy national requirements for environmental protection.
Summary of the invention
The objective of the invention is provides a kind of forced circulation dum boiler that has the flue gas temperature elevation system in order to solve the forced circulation dum boiler technical problem that the SCR reactor can't put into operation under underload and/or atmospheric temperature low condition.Namely by the water system of existing forced circulation dum boiler is transformed, what propose utilizes the stove water pump that part high temperature saturation water is delivered to the side-entrance of boiler economizer water to mix with the feedwater of economizer, to improve the feed temperature of economizer, and then improve the boiler economizer exit gas temperature, make it temperature and reach the Applicable temperature that the SCR reactor puts into operation.The present invention is applicable to subcritical and forced circulation dum boiler super-pressure.
Know-why of the present invention
The flow process of former boiler water side is that feedwater enters drum after heating up through economizer.The saturation water of the bottom of drum is through down-comer, is driven into the Xia Shuibao of boiler by the stove water pump, and the water of following water bag is by the water-cooling wall draw heat that rises, thereby part is evaporated to steam, and steam water interface enters drum and finishes carbonated drink separation.Saturated vapor after the separation enters superheater, and saturation water then enters down-comer and continues circulation.
The saturation water that transformation has increased the bottom of drum can partly enter economizer, the mixing of the feedwater of this part saturation water and economizer has improved the temperature of economizer entrance, thereby reduced the temperature difference of water and flue gas in the economizer, cause the minimizing of flue gas thermal discharge, the temperature of economizer exit flue gas has had raising to a certain degree, therefore the entrance flue gas temperature that enters the SCR reactor also raises, the amount that enters the saturation water of economizer entrance by adjusting is adjusted the temperature of economizer entrance, the flue-gas temperature of the step of going forward side by side joint SCR reactor inlet makes it to reach the put into operation temperature of required flue gas of SCR reactor.
Technical scheme of the present invention
A kind of forced circulation dum boiler that has the flue gas temperature elevation system comprises boiler, drum, stove water pump, economizer, SCR reactor, air preheater, also comprises the flue gas temperature elevation system;
Described flue gas temperature elevation system comprises electric control valve 1, electric control valve 2, the import of described stove water pump is connected with the down-comer of drum, the outlet of stove water pump is divided into two-way, the electric control valve 1 of leading up to is connected with the following water bag of boiler, and the electric control valve 2 of leading up to is in parallel with the feed-water intake pipeline of economizer.
The operation principle of above-mentioned a kind of forced circulation dum boiler that has a flue gas temperature elevation system is as follows:
The schematic flow sheet of former boiler water side enters drum after feedwater process economizer heats up as shown in Figure 1.The saturation water of the bottom of drum is driven into Xia Shuibao through down-comer by the stove water pump, and the water of following water bag is by the water-cooling wall draw heat that rises, thereby part is evaporated to steam, and steam water interface enters drum and finishes carbonated drink separation.Saturated vapor after the separation enters superheater, and saturation water then enters down-comer and continues circulation.
Have the flue gas temperature elevation system dum boiler the water side schematic flow sheet as shown in Figure 2, the saturation water of drum bottom is through the stove water pump, then through the i.e. adjustment door 1 among the figure of electric control valve 1, electric control valve 2 i.e. adjustment door 2 among the figure is regulated the saturated water amount that enters economizer, the mixing that enters the feedwater of this part saturation water of economizer and economizer improves the temperature of economizer entrance, thereby reduced the temperature difference of water and flue gas in the economizer, cause the minimizing of flue gas thermal discharge, the temperature of economizer exit flue gas has had raising to a certain degree, thereby makes the temperature of the flue gas that enters the SCR reactor can satisfy the Applicable temperature that the SCR reactor puts into operation.
A kind of forced circulation dum boiler that has the flue gas temperature elevation system of the present invention is applicable to subcritical and forced circulation dum boiler super-pressure.
Beneficial effect of the present invention
A kind of forced circulation dum boiler that has the flue gas temperature elevation system of the present invention, by increasing electric control valve 1, electric control valve 2 and corresponding pipeline, the mixing of the feedwater of the fractional saturation water in the drum and economizer is improved the temperature of economizer entrance, thereby reduced the temperature difference of water and flue gas in the economizer, make the minimizing of the flue gas thermal discharge in the economizer, the temperature of the flue gas of economizer exit raises, make the flue-gas temperature that enters the SCR reactor can satisfy the Applicable temperature that puts into operation of SCR reactor, therefore, by increasing the flue gas temperature elevation system, guaranteed dum boiler SCR reactor normally operation under underload and/or atmospheric temperature low condition of former forced circulation, thereby guaranteed that the forced circulation dum boiler fume emission quality under the subcritical and super-pressure under underload and/or the atmospheric temperature low condition also can be up to state standards.
Further, a kind of forced circulation dum boiler of flue gas temperature elevation system that has of the present invention is by the transformation of water side, effectively solved low and the problem that SCR reactor that cause is stopped transport of under underload and/or atmospheric temperature low condition SCR inlet flue gas temperature, other method than the water side has the amplitude that promotes flue-gas temperature big, and system is simple, investment for trnasforming urban land is few, to the little characteristics of other operating mode influence.Further comparing maximum characteristics of the present invention with the fume side remodeling method is little, the small investments of The reconstruction scope, and the construction time is short.
Further, a kind of forced circulation dum boiler that has the flue gas temperature elevation system of the present invention can be saved investment cost over half at least with economizer classification raising cigarette temperature method commonly used at present.
Description of drawings
The schematic diagram of Fig. 1, the former water effluent of forced circulation dum boiler journey;
Fig. 2, have the schematic diagram of water effluent journey of the forced circulation dum boiler of flue gas temperature elevation system;
The graph of a relation of the situation that puts into operation of the SCR reactor of Fig. 3, subcritical 300MW forced circulation dum boiler and unit load, ambient temperature;
The structural representation of Fig. 4, subcritical 300MW forced circulation dum boiler;
Fig. 5, have the structural representation of the subcritical 300MW forced circulation dum boiler of flue gas temperature elevation system.
The specific embodiment
Also by reference to the accompanying drawings the present invention is further set forth below by concrete Application Example, but do not limit the present invention.
Application Example 1
A kind of forced circulation dum boiler that has the flue gas temperature elevation system is that example is introduced with subcritical 300MW forced circulation dum boiler namely:
One, the subcritical 300MW forced circulation dum boiler with Waigaoqiao of Shaihai generating Co., Ltd is example, and this subcritical 300MW forced circulation dum boiler technical parameter is as follows:
Boiler model: SG-1025/18.3-M831
Major parameter:
Superheated steam (MCR) reheated steam (MCR)
Flow 1025 t/h flow 830t/h
Pressure 18.3 Mpa pressure 3.85/3.66 Mpa
323/541 ℃ of 541 ℃ of temperature of temperature
The SCR reactor moves the requirement for the smoke inlet temperature:
Inlet temperature≤314 ℃ warning
314 ℃<inlet temperature>308 ℃ time-delay 1h stop to spray ammonia
Inlet temperature≤308 ℃ stop to spray ammonia SCR and stop transport
The unit load size influences boiler economizer outlet cigarette temperature, namely directly influences 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 more low, and putting into operation of SCR reactor will be at the boiler high-load region.
The 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 more low, unit is when high load capacity, and the 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;
When ambient temperature raise, for example, ambient temperature was 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 when 140MW load is following, and the economizer exhaust gas temperature can't satisfy the SCR reactor condition that puts into operation.
Two, subcritical 300MW forced circulation dum boiler original system and operating mode
The structural representation of subcritical 300MW forced circulation dum boiler comprises boiler-steam dome, stove water pump, economizer, SCR reactor, air preheater as shown in Figure 4, and the import of stove water pump is connected with the down-comer of drum, and the outlet of stove water pump is connected with the following water bag of boiler.
When unit when 35% rated load (136MW), subcritical 300MW forced circulation dum boiler operational factor is 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 given 265 ℃ of water outlet temperatures.At this moment, 290 ℃ of economizer exhanst gas outlet temperature are lower than 310 ℃ of the minimum temperatures that the SCR reactor puts into operation.Therefore, must improve boiler economizer outlet cigarette temperature, thereby improve SCR reactor inlet flue-gas temperature, namely satisfy 310 ℃ of the minimum temperatures that the SCR reactor puts into operation, thereby the SCR reactor is put into operation.
Three, the subcritical 300MW forced circulation dum boiler that has the flue gas temperature elevation system is implemented in that the SCR reactor puts into operation under the condition of underload
Have the flue gas temperature elevation system subcritical 300MW forced circulation dum boiler structural representation as shown in Figure 5, comprise boiler-steam dome, stove water pump, economizer, SCR reactor, air preheater, also comprise the flue gas temperature elevation system, described flue gas temperature elevation system comprises the i.e. i.e. adjustment door 2 among the figure of adjustment door 1 among the figure, electric control valve 2 of electric control valve 1;
The import of described stove water pump is connected with the down-comer of drum, and the outlet of stove water pump is divided into two-way, and the electric control valve 1 of leading up to is connected with the following water bag of boiler, and the electric control valve 2 of leading up to is in parallel with the feed-water intake pipeline of economizer.
Four, have the subcritical 300MW forced circulation dum boiler operation of flue gas temperature elevation system, its operational factor as shown in Figure 5:
When load is low, the economizer exit flue-gas temperature is low, thereby when making SCR reactor inlet flue-gas temperature be lower than the entrance flue gas temperature that the SCR reactor puts into operation required, the SCR reactor can not move, and needs to start the flue gas temperature elevation system:
At first open the adjustment door 2 of stove exit of pump, adjust the aperture of door 1 then, the saturated water amount that enters Xia Shuibao is reduced, the amount of the saturation water that enters economizer is increased, when economizer exit cigarette temperature reaches 315 ℃, stop to adjust the aperture of door 1, at this moment, the entrance flue gas temperature that enters the SCR reactor meets the flue-gas temperature that the SCR reactor puts into operation, and the SCR reactor brings into operation.
When load raises, when economizer exit cigarette temperature reaches SCR reactor service condition, close the flue gas temperature elevation system, do not influence the normal operation of original subcritical 300MW forced circulation dum boiler.
Above said content only is the basic explanation of the present invention under conceiving, and according to technical scheme of the present invention institute
Any equivalent transformation of doing all should belong to protection scope of the present invention.

Claims (1)

1. a forced circulation dum boiler that has the flue gas temperature elevation system comprises boiler, drum, stove water pump, economizer, SCR reactor, air preheater, it is characterized in that also comprising the flue gas temperature elevation system;
Described flue gas temperature elevation system comprises electric control valve 1, electric control valve 2, the import of described stove water pump is connected with the down-comer of drum, the outlet of stove water pump is divided into two-way, the electric control valve 1 of leading up to is connected with the following water bag of boiler, and the electric control valve 2 of leading up to is in parallel with the feed-water intake pipeline of economizer.
CN 201310128405 2013-04-15 2013-04-15 Forced-circulation drum boiler with flue heating system Pending CN103196133A (en)

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CN 201310128405 CN103196133A (en) 2013-04-15 2013-04-15 Forced-circulation drum boiler with flue heating system
CN2013103171943A CN103343953A (en) 2013-04-15 2013-07-26 Forced circulation drum boiler with smoke temperature rising system

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105889899A (en) * 2014-12-16 2016-08-24 华北电力大学(保定) Superheated steam temperature adjusting system and method suitable for SCR low-load operation

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103939885B (en) * 2014-03-28 2016-03-09 上海发电设备成套设计研究院 A kind of feedwater displaced type economizer system put into operation for denitration device whole process

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JP2923172B2 (en) * 1993-06-22 1999-07-26 三菱重工業株式会社 Economizer
JP2930520B2 (en) * 1994-04-13 1999-08-03 三菱重工業株式会社 Heat recovery unit for boiler with denitration equipment
US6609483B1 (en) * 2002-02-27 2003-08-26 The Babcock & Wilcox Company System for controlling flue gas exit temperature for optimal SCR operations
US7578265B2 (en) * 2006-05-09 2009-08-25 Babcock & Wilcox Power Generation Group, Inc. Multiple pass economizer and method for SCR temperature control
CN102937295B (en) * 2012-11-20 2015-02-18 上海锅炉厂有限公司 Boiler economizer arrangement form suitable for denitration device negative whole process load operation
CN203595112U (en) * 2013-04-15 2014-05-14 上海上电电力工程有限公司 Forced circulation drum boiler with smoke warming system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105889899A (en) * 2014-12-16 2016-08-24 华北电力大学(保定) Superheated steam temperature adjusting system and method suitable for SCR low-load operation

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Application publication date: 20130710