CN114110570A

CN114110570A - W flame boiler capable of flexibly adjusting peak by using reserved coal bunker and boiler peak adjusting method

Info

Publication number: CN114110570A
Application number: CN202111282647.4A
Authority: CN
Inventors: 李争起; 杜贺; 郑玉; 张鸣镝; 陈智超; 宋健
Original assignee: Hunan Datang Energy Saving Science And Technology Co ltd; Harbin Institute of Technology
Current assignee: Hunan Datang Energy Saving Science And Technology Co ltd; Harbin Institute of Technology
Priority date: 2021-11-01
Filing date: 2021-11-01
Publication date: 2022-03-01

Abstract

The invention relates to a W flame boiler and a boiler peak regulation method which utilize a reserve coal bunker to flexibly regulate peak, in particular to a W flame boiler and a boiler peak regulation method which flexibly regulate peak, aiming at solving the problems of great difficulty in the flexible peak regulation technology and poor boiler deep peak regulation capability of the existing W flame boiler, and comprising a reserve coal bunker system, a boiler body, a double-cyclone barrel burner and a secondary air box; the coal storage bin system comprises a first storage bin, a mixing bin and a coal mill; a first deposit with boiler body preceding stove arch go up two cyclone combustor intercommunication, another first deposit storehouse and boiler body after the stove arch go up two cyclone combustor intercommunication, step one: preparing; step two: and (3) combustion work: starting the boiler body to work; step three: peak regulation work: the peak regulation work of the boiler body is carried out by controlling the quality and the type of the pulverized coal entering the boiler body from the first storage bin and the mixing bin, and the coal supply ratio of the high-quality bituminous coal stored in the second storage bin is changed. The invention belongs to the field of boilers.

Description

W flame boiler capable of flexibly adjusting peak by using reserved coal bunker and boiler peak adjusting method

Technical Field

The invention relates to a W flame boiler with flexible peak regulation and a boiler peak regulation method, in particular to a W flame boiler with flexible peak regulation by utilizing a reserve coal bunker and a boiler peak regulation method, and belongs to the field of boilers.

Background

The W-flame boiler is a power station boiler which is introduced from the areas of North Africa and Western Europe and the like from the nineties of the twenty-century in China and is specially designed for burning low-volatile and difficult-to-burn coal types such as lean coal, anthracite and the like. Because the anthracite and lean coal have compact and stable lithofacies structures, small porosity and low reactivity, the problems of difficult ignition, difficult stable combustion and difficult burnout exist in actual combustion, higher ignition temperature and burnout temperature are needed, and the coal powder burnout time is longer. When the boiler is operated under low load, the temperature of the hot air is reduced because the quantity of fuel fed into the boiler is less, and the primary air and the secondary air are reduced along with the reduction of the quantity of the fuel. The oxygen content in the furnace is relatively high, and the heat load in the furnace and the temperature of a hearth are low. The combustion stability of the boiler will be further deteriorated and even cause fire extinguishment. Therefore, compared with other coal-fired utility boilers, the W flame boiler has the difficulties in flexible peak regulation and is heavy.

In recent years, with the intervention of large-scale renewable energy sources, the power system in china has changed greatly. The power generation capacity of renewable energy sources accounts for an increasing proportion of the power grid. However, due to the limitation of the power generation mode, the instability of the output of the renewable energy power generation brings a great challenge to the regulation capability of the power system; in addition, a large number of uncertain factors on the power generation side and the demand side also affect the safe and stable operation of the power system. The data shows that the net thermal power increasing electric installation machine 7202 ten thousand kilowatts (wherein the coal power is 5186 ten thousand kilowatts) in China in 2015 all the year is the largest year of production in 2009. However, the power generation amount of thermal power is continuously and negatively increased for two years, and the utilization rate is new and low since 1969. In addition, in recent years, while wind power is continuously and rapidly developed, serious wind abandon problems occur in partial areas, and consumption becomes a key factor for restricting the development of new energy resources such as wind power. Therefore, in order to adapt to the high-speed development of renewable energy sources, improve the consumption capacity of a power system on the renewable energy sources, ensure the safe and stable operation of the power system, and flexibly modify a coal-electric machine set, the method is imperative.

Because the main limiting factor of the W flame boiler for flexible peak regulation is the particularity of the coal quality for combustion, the W flame boiler is difficult to flexibly peak regulate because of the poor anthracite and lean coal which are difficult to stably combust. Flexible peak shaving is difficult to achieve in the short term by combustion technology optimization and combustion tuning alone. Therefore, the fuel structure of the boiler is properly adjusted, and high-quality coal types such as soft coal and the like which have high volatile contents and are easy to catch fire and stably burn are mixed and burned, so that the W flame boiler is an effective technology of the flexible peak regulation technology of the W flame boiler at the present stage and has wide application prospects.

Disclosure of Invention

The invention aims to solve the problems of high difficulty and poor deep peak regulation capability of the conventional W flame boiler, and further provides a W flame boiler and a boiler peak regulation method for flexibly regulating peaks by using a reserve bunker.

The technical problem is solved by the following scheme:

the system comprises a coal storage bin system, a boiler body, two groups of double-cyclone-cylinder combustors and a secondary air box; the coal storage bin system comprises two first storage bins, two mixing bins and four coal mills; two sets of two dryer combustors install respectively on the preceding arch of boiler body and the back arch of a furnace, the secondary bellows is installed in boiler body periphery, a first deposit storehouse passes through a coal pulverizer and encircles a set of dryer combustor intercommunication before the boiler body, another first deposit storehouse encircles a set of dryer combustor intercommunication after passing through coal pulverizer and boiler body, a mixed storehouse passes through a coal pulverizer and encircles a set of dryer combustor intercommunication before boiler body, another mixed storehouse encircles a set of dryer combustor intercommunication after passing through coal pulverizer and boiler body.

The method is realized according to the following steps:

the method comprises the following steps: preparation work: poor anthracite and lean coal are stored in the basic bin and the first storage bin, and high-quality bituminous coal is stored in the second storage bin;

step two: and (3) combustion work: starting the boiler body to work;

step three: peak regulation work: the peak regulation work is set according to the requirement, the boiler body is enabled to carry out the peak regulation work by controlling the quality and the type of the coal powder entering the boiler body from the first storage bin and the mixing bin, the coal feeding amount ratio of the high-quality bituminous coal stored in the second storage bin is changed, and the effect of the peak regulation work of the W flame boiler is further achieved.

Compared with the prior art, the invention has the following beneficial effects:

1. the invention can realize simultaneous combustion of anthracite, lean coal and soft coal in the same boiler

In the prior art, domestic W flame boilers in active service only have a common coal bunker system, and the coal quality for daily combustion is usually that the dry ashless volatile component of inferior anthracite is less than or equal to 9 percent or the dry ashless volatile component content of lean coal is 9 to 19 percent. V of these coal types_dafThe content is about 10 percent generally, V_dafThe ash-free base volatile matter is one of important indexes of coal classification for drying, the ash content is high, the structure is compact, the coal is difficult to catch fire and burn out, and the ignition temperature of coal dust airflow can reach 900 ℃ or even higher. In order to burn anthracite and lean coal, the conventional W flame boiler generally adopts a dense-dilute separation combustion mode to reduce primary air speed, so that the primary air coal dust concentration is improved, the ignition distance of coal dust airflow is shortened, and the coal dust airflow is ensured to be ignited in time. Meanwhile, a large number of combustion preventing belts are usually laid in the W flame boiler, so that the temperature of a hearth can reach over 1200 ℃, and therefore stable combustion of pulverized coal after ignition is ensured and burnout of the pulverized coal is promoted. If in ordinary coalThe bunker is mixed with bituminous coal or only the bituminous coal is dried and the volatile component content of the ash-free base is reduced>19% of the total load, when the boiler is above 60% of rated load, due to V of coal_dafThe content is higher, the ignition temperature of the coal dust airflow can be greatly reduced to 600 ℃ or even lower, and the ignition distance of the coal dust airflow is obviously shortened. When the same combustion method as that of anthracite is adopted, a high-temperature area formed by firing of pulverized coal airflow is close to a burner nozzle, so that the burner nozzle is easy to burn and deform, and a high primary air speed is required. Meanwhile, due to the fact that ignition is advanced and the required burnout distance is shortened, after bituminous coal is burnt, the main burning zone of pulverized coal is completely concentrated in the lower hearth area, the temperature of the lower hearth can reach 1500 ℃ or even higher, and the heating surface is extremely easy to be over-heated. And the ash content carried in the coal dust is heated to a molten state at the high temperature of 1500 ℃, so that the ash content is easy to adhere to a burning control belt of a furnace wall to cause a serious slag bonding problem, and the safe operation of the boiler is threatened. Therefore, the conventional W-flame boiler with only a common coal bunker system can only be suitable for burning low-quality coal such as anthracite, lean coal and the like.

The invention stores high-quality bituminous coal by arranging the coal storage bin system, flexibly changes the quality of coal entering the boiler according to the operation load of the boiler, and can realize the simultaneous combustion of the anthracite, the lean coal and the bituminous coal by the same boiler. The coal bunker system of the boiler comprises a storage coal bunker system and a common coal bunker system. The number of the coal storage bunker systems is the same as that of the common coal bunker systems, and the coal storage bunker systems and the common coal bunker systems are symmetrically arranged around the central line of the hearth. The boiler stores low-quality anthracite, lean coal and bituminous coal daily. Daily storage V in basic coal bunker_dafAbout 5 to 15 percent of inferior anthracite or lean coal, and the stored coal bunker is used for daily storage of V_daf25 to 40 percent of high-quality bituminous coal. When the boiler operates at a rated load of more than 60 percent, due to the fact that the coal amount fed into the boiler is relatively high, the pulverized coal is burnt in a hearth to release enough heat, and the temperature of the hearth is improved. The pulverized coal airflow can still be timely ignited and stably combusted when anthracite and lean coal are combusted, and stable operation of the boiler is realized. When the boiler is in 40-60% of normal low load, the temperature of the hearth is reduced due to the reduction of the coal amount fed into the boiler, and then the inferior anthracite, the lean coal and the reserve coal in the basic coal bunker are added according to the load levelHigh-quality bituminous coal in the bin is blended to form mixed coal with 16-25% of volatile components, and stable operation of the mixed coal can be still ensured without changing the combustion mode of a boiler. When the boiler is in 20-40% rated load deep peak shaving, compared with the conventional load, the coal feeding amount of the boiler is greatly reduced, the temperature of a hearth is greatly reduced, and the burning conditions of anthracite and lean coal cannot be met. Meanwhile, in order to ensure the normal conveying of the pulverized coal, the primary air speed of the boiler is still kept at a high level, and the burning requirement of the bituminous coal is completely met. Therefore, under the load condition, the coal quality of the boiler is completely supplied by the high-quality bituminous coal in the reserve coal bunker. After the high-quality bituminous coal is fed into the hearth, the high-quality bituminous coal still can be ignited in time at a relatively low hearth temperature and can be sufficiently combusted in the lower hearth to release enough heat, so that the stable operation of the boiler is ensured. In conclusion, the invention flexibly adjusts the burning of the anthracite and the bituminous coal according to the load of the boiler, and the coal quality put into the boiler is changed in time according to the actual operation condition of the boiler. The boiler can realize the simultaneous combustion of anthracite, lean coal and bituminous coal by the same boiler while ensuring the stable operation of the boiler under various load states, and the adaptability to coal types is greatly improved.

2. The invention can simultaneously realize the stable operation of the W flame boiler with full load, normal low load and 20 to 40 percent ultralow load

Since the conventional W-flame boiler is designed to burn low-quality anthracite or lean coal. When the boiler is in normal low-load or full-load operation, the coal amount put into the boiler is large. The coal powder is burnt in the hearth to release a large amount of heat, so that the temperature of the hearth can be maintained to be above 1000 ℃, and the stable combustion of anthracite and lean coal can be ensured. However, when the boiler load is reduced to a lower level, because the fuel quantity fed into the boiler is greatly reduced, and the primary air speed is reduced, the burnout distance of the pulverized coal airflow in the lower hearth is shortened, pulverized coal particles cannot be sufficiently combusted in the hearth, so that the temperature in the lower hearth is greatly reduced, and the pulverized coal airflow cannot be stably combusted and even can extinguish fire. At present, the minimum oil-free stable combustion load of an existing W flame boiler is only about 50%, and the stable combustion of 20-40% of ultralow load and even ultralow load cannot be realized. Therefore, the traditional W flame boiler can not realize the stable operation of the full load, the conventional low load and the 20-40% ultra-low load of the W flame boiler simultaneously only through operation adjustment.

The invention realizes the stable operation of the same boiler under the conditions of full load, normal low load and 20-40% ultra-low load by arranging the external coal blending system and flexibly adjusting the quality of the coal entering the boiler. When the boiler is operated at the normal load and the full load of more than 60 percent, the coal as fired is completely supplied by the basic coal bunker, and the quality of the coal as fired is about 10 percent of anthracite and lean coal. Under the load condition, the boiler fuel supply is large, the pulverized coal burns in the hearth to release more heat, the temperature in the hearth can be maintained above 1000 ℃, and the pulverized coal airflow is guaranteed to catch fire and stably burn in time after being sprayed into the hearth, so that the stable burning of the boiler is realized. When the boiler is in 40-60% normal low-load operation, all coal mills and burners of the W flame boiler are still put into use, but because the amount of coal entering the boiler is reduced, the temperature of a hearth is reduced, and the temperature conditions in the boiler can not meet the requirements of ignition and stable combustion of pulverized coal airflow when only anthracite and lean coal are combusted. At this time, the basic bunker and the reserve bunker are put into use at the same time. The inferior power coal in the basic coal bunker and the high quality soft coal in the reserve coal bunker are reasonably proportioned according to the requirement of the boiler load to ensure that the V of the coal quality entering the boiler is_dafThe content reaches 10-20%, the ignition point of the coal dust airflow is reduced to about 800 ℃, meanwhile, the burnout distance required by coal dust combustion is shortened, more heat is released in the lower hearth, the temperature level in the hearth is improved, and therefore timely ignition and stable combustion of the coal dust airflow are guaranteed. When the boiler is in a deep peak shaving state of 20-40%, the coal grinding machines and the burners of the boiler are all put into use due to the fact that the fuel quantity entering the boiler is greatly reduced, the coal powder concentration of primary air of the burners is reduced to an extremely low level, and the firing conditions cannot be met. At this time, the power plant usually stops 1-2 coal mills to increase the pulverized coal concentration of the primary air of the operating combustor. As the amount of coal powder entering a boiler is greatly reduced, the temperature of a hearth is greatly reduced, and meanwhile, in order to ensure that the wind speed of primary air of the powder feeding capacity is still kept about 15m/s, when 10-20% of lean coal is used by a boiler, the timely ignition and stable combustion of coal powder airflow cannot be effectively ensured. At this time, the process of the present invention,the basic coal bunker is stopped, the boiler only uses the stored coal bunker V_dafHigh-quality bituminous coal with the content of more than 20 percent. The ignition point of the pulverized coal airflow can be greatly reduced to about 700 ℃ under the condition of the air-coal ratio of ultra-low load, and the pulverized coal airflow can not cause damage to a burner nozzle after being ignited under the condition of reducing the powder feeding amount. Meanwhile, the flow distance and the time required by the pulverized coal airflow after being burnt out are greatly shortened, the pulverized coal airflow can be fully combusted in the lower hearth, more heat is released, the overall temperature level of the lower hearth area is improved, and the pulverized coal airflow is ensured to catch fire and stably combust in time so as to ensure the stable operation of the boiler. Therefore, the invention can realize the stable operation of the same boiler under the conditions of full load, normal low load and 20-40% ultra-low load through operation adjustment.

3. The invention can realize the flexible peak regulation of the boiler

In recent years, in order to solve the problem of deep peak regulation of the boiler, various measures for improving the low-load stable combustion capacity of the boiler are provided for the thermal power plant. The most effective measure at present is to store a certain amount of high-quality bituminous coal, and change the coal quality for boiler combustion from low-quality anthracite coal into high-quality bituminous coal which is easy to ignite and stably combust under the conditions of low load and ultralow load of the boiler. The measure can effectively improve the low-load stable combustion capacity of the boiler and realize deep peak regulation. But can be effectively developed only on the premise of predicting the requirement of the boiler on deep peak regulation. And the coal quality of a boiler coal burning system is changed and the operation scheduling of a coal yard needs certain transition time, so the flexible peak shaving capacity of the measure is very limited, and the flexible peak shaving requirement of a future thermal power plant cannot be met.

In the invention, a certain amount of high-quality bituminous coal is stored in a power plant for a long time by constructing parallel inferior and high-quality coal supply systems outside the boiler. When the boiler has the requirement of deep peak regulation, the coal quantity regulating valves of the basic coal bunker and the reserve coal bunker are adjusted in time, and the coal quantity ratio of the inferior coal and the high-quality coal is changed, so that the coal quality characteristic of the boiler entering the boiler can be effectively changed, and the requirement of low-load stable combustion is met. When the boiler needs to be adjusted to be operated at full load, the load adjustment of the boiler can be realized while the stable and safe operation of the boiler is ensured by changing the coal amount ratio of the basic coal bunker and the reserved coal bunker and improving the ratio of anthracite to lean coal in the coal as fired. According to the invention, only the coal quantity regulating valve of the coal bunker needs to be regulated during peak regulation, and no additional operation scheduling is needed, so that the operation is convenient and fast, and the flexible peak regulation of the boiler can be realized.

Drawings

Fig. 1 is a schematic view of the overall structure of the present application.

Fig. 2 is a schematic diagram of the connection of the coal storage bunker system and the double-cyclone cylinder burner 8.

Detailed Description

The first embodiment is as follows: the embodiment is described with reference to fig. 1-2, and the W-flame boiler using the reserve coal bunker for peak shaving comprises a reserve coal bunker system, a boiler body 7, two groups of double-cyclone-barrel burners 8 and a secondary air box 9; the coal storage bin system comprises two first storage bins 2, two mixing bins and four coal mills 5; two sets of two dryer combustors 8 are installed respectively on the preceding arch of boiler body 7 and the back arch of a stove, secondary bellows 9 is installed in 7 peripheries of boiler body, a first deposit storehouse 2 encircles a set of dryer combustor 8 intercommunication through coal pulverizer 5 and 7 preceding arches of boiler body, another first deposit storehouse 2 encircles a set of dryer combustor 8 intercommunication through coal pulverizer 5 and 7 back arches of boiler body, a mixed storehouse encircles a set of dryer combustor 8 intercommunication through coal pulverizer 5 and 7 preceding arches of boiler body, another mixed storehouse encircles a set of dryer combustor 8 intercommunication through coal pulverizer 5 and 7 back arches of boiler body.

Inferior anthracite or lean coal with Vdaf of about 5-15% is daily stored in the basic coal bin 1, and high-quality bituminous coal with Vdaf of 25-45% is daily stored in the second storage bin 2-1;

the second embodiment is as follows: the embodiment is described with reference to fig. 1-2, and the W-flame boiler using the reserve coal bunker for peak shaving in the embodiment includes a basic bunker 1 and a second reserve bunker 2-1, and both the basic bunker 1 and the second reserve bunker 2-1 are communicated with a coal mill 5. Other components and connection modes are the same as those of the first embodiment.

The third concrete implementation mode: the embodiment is described by combining fig. 1-2, the W-flame boiler using the reserve coal bunker for peak shaving in the embodiment further comprises a blender 4, and the basic bunker 1 and the second reserve bunker 2-1 are communicated with a coal mill 5 through the blender 4. Other components and connection modes are the same as those of the second embodiment.

The fourth concrete implementation mode: the embodiment is described with reference to fig. 1-2, and the W-flame boiler using the reserve coal bunker to adjust peak flexibly according to the embodiment further includes two coal quantity adjusting valves 3; the basic bin 1 is communicated with a coal quantity adjusting valve 3, the second storage bin 2-1 is communicated with the coal quantity adjusting valve 3, and the two coal quantity adjusting valves 3 are communicated with a blender 4. Other components and connection modes are the same as those of the third embodiment.

The fifth concrete implementation mode: the embodiment is described with reference to fig. 1-2, and the W-flame boiler using the reserve coal bunker to perform peak shaving flexibly in the embodiment further includes a plurality of coal conveying pipelines 6, the first reserve coal bunker 2 is communicated with each group of double cyclone barrel burners 8 on the boiler body 7 through the coal conveying pipelines 6, and the mixing bunker is communicated with each group of double cyclone barrel burners 8 on the boiler body 7 through the coal conveying pipelines 6. Other components and connection modes are the same as those of the first embodiment.

The sixth specific implementation mode: the embodiment is described with reference to fig. 1, and the embodiment utilizes a W flame boiler with a flexible peak regulation of the reserve coal bunker, the reserve coal quantity of the second reserve coal bunker 2-1 is 0.5-0.8 times of the coal quantity of the basic bunker 1, and the daily coal quantity of the first reserve coal bunker 2 is the same as the daily coal quantity of the basic bunker 1. Other components and connection modes are the same as those of the first embodiment.

The seventh embodiment: the embodiment is described by combining the figures 1-2, and the embodiment utilizes the boiler peak shaving method of the W flame boiler with the reserve coal bunker flexible peak shaving, and the method is realized according to the following steps:

the method comprises the following steps: preparation work: poor anthracite and lean coal are stored in the basic bin 1 and the first storage bin 2, and high-quality bituminous coal is stored in the second storage bin 2-1;

step two: and (3) combustion work: starting the boiler body 7 to work;

step three: peak regulation work: the peak shaving work is set according to the requirement, the boiler body 7 is enabled to carry out the peak shaving work by controlling the quality and the type of the pulverized coal entering the boiler body 7 through the first storage bin 2 and the mixing bin, and the peak shaving work of the W flame boiler is further achieved.

V is stored in a basic coal bunker 1_daf5 to 15 percent of inferior anthracite or lean coal, and V is stored in the second storage bin 2-1_daf25 to 40 percent of high-quality bituminous coal.

The specific implementation mode is eight: the present embodiment is described with reference to fig. 1, and the peak shaving method of the boiler using the W flame boiler with the reserve coal bunker for peak shaving in the present embodiment is that in the third step, when the boiler load needs to work at a rated load of more than 60%, the second reserve coal bunker 2-1 stops working, only the basic coal bunker 1 and the first reserve coal bunker 2 supply pulverized coal, and only the pulverized coal supplied by the basic coal bunker 1 and the first reserve coal bunker 2 in the boiler body 7 performs combustion work. The other components and the connection mode are the same as those of the seventh embodiment.

The specific implementation method nine: the peak regulation method of the boiler of the W flame boiler is explained by combining with the figure 1, the peak regulation work in the third step is that when the boiler works with the working load of 40% -60% of the rated load, 40% is not included, the basic bin 1, the first storage bin 2 and the second storage bin 2-1 work, the high-quality coal with the volatile content of 20% -30% and the low-quality coal are supplied to the coal powder in proportion, the low-quality coal and the high-quality bituminous coal are mixed into the mixed coal with the Vdaf of 16% -25% by the mixer 4 and are supplied to the boiler, and the coal powder in the boiler body 7 is burnt. The other components and the connection mode are the same as those of the seventh embodiment.

The detailed implementation mode is ten: the peak shaving operation in the third step is that when the boiler is deeply peak-shaving operation with the rated load of 20% -40% of the working load of the boiler, the basic bin 1 and the first storage bin 2 stop supplying coal powder, the second storage bin 2-1 supplies coal powder, high-quality coal with the volatile component content of 30% -40% is supplied to the coal powder, and the coal powder in the boiler body 7 is combusted. The coal as fired adopts high-quality bituminous coal with 25-40% of Vdaf in the second storage bin 2-1, and the other components and connection modes are the same as those of the seventh specific embodiment.

Principle of operation

Example (b): the invention has been applied to a 300MW FW type W flame boiler in a certain power plant. 12 groups of 24 double-cyclone-cylinder thick-thin pulverized coal burners are symmetrically arranged on the front wall and the rear wall of the boiler. The boiler was equipped with A, B, C, D4 coal mills, each supplying 3 sets of burners. B, D two coal mills adopting the rear boiler are provided with a reserve coal bunker system. High-quality bituminous coal with coal dry ashless volatile components of 10-15% and dry ashless volatile components of 20-25% is stored in a basic coal bunker.

Before the invention is adopted, 24 burners on the front wall and the rear wall of the boiler are all put into operation and can keep stable operation under the full load condition. However, when the boiler load is reduced to 120MWe, namely 40% BMCR load, A, C two mills of the boiler are stopped, only B, D two coal mills are put into operation, and actual operation shows that 12 traditional combustors corresponding to the two mills have the phenomena of difficult ignition, unstable combustion and even fire extinguishing to different degrees, and the ignition point temperature of pulverized coal airflow is measured to be about 950 ℃ through tests. The ignition distance of the burner can reach more than 2 m. The lowest oil-free and combustion-stabilizing load of the boiler is only about 50% of the rated load. And because the coal quality of the daily combustion of the boiler changes, the problems of overheating of a reheater and a wall and slag bonding on the side of a wing wall often occur in the running process of the boiler.

After the invention is adopted, when only B, D mills are put into operation, the ignition points of the burners are all about 1.2m by adjusting the coal blending quantity of the basic coal bunker and the reserve coal bunker, the ignition point temperature of the pulverized coal airflow is reduced to about 600 ℃ through test measurement, the pulverized coal airflow is ignited in time, and the stable combustion characteristic is good. When the boiler load is reduced to 20%, the 12 burners can still be stably put into operation by adjusting the ratio of high-quality coal to low-quality coal. And the problems of the reheater and the wall temperature of the boiler over-temperature disappear, and the problem of slag bonding on the wing wall side is light.

Claims

1. The W flame boiler utilizing the reserve coal bunker to adjust peak flexibly comprises a reserve coal bunker system, a boiler body (7), two groups of double-cyclone-barrel combustors (8) and a secondary air box (9); the method is characterized in that: the coal storage bin system comprises two first storage bins (2), two mixing bins and four coal mills (5); two sets of two-cyclone burner (8) are installed respectively on the preceding arch of boiler body (7) and on the back arch of a stove, secondary bellows (9) are installed in boiler body (7) periphery, one first deposit storehouse (2) are through coal pulverizer (5) and boiler body (7) preceding arch of a stove on a set of two-cyclone burner (8) intercommunication, another first deposit storehouse (2) are through coal pulverizer (5) and boiler body (7) back arch of a stove on a set of two-cyclone burner (8) intercommunication, a mix storehouse is through coal pulverizer (5) and boiler body (7) preceding arch of a stove on a set of two-cyclone burner (8) intercommunication, another mixes storehouse and encircles a set of two-cyclone burner (8) intercommunication behind boiler body (7) through coal pulverizer (5).

2. The W-flame boiler with flexible peak shaving using a reserve bunker as claimed in claim 1, wherein: the mixing bin comprises a basic bin (1) and a second storage bin (2-1), and the basic bin (1) and the second storage bin (2-1) are communicated with a coal mill (5).

3. The W-flame boiler with flexible peak shaving using a reserve bunker as claimed in claim 2, wherein: the mixing bin further comprises a blender (4), and the basic bin (1) and the second storage bin (2-1) are communicated with the coal mill (5) through the blender (4).

4. The W-flame boiler with flexible peak shaving using a reserve bunker as claimed in claim 3, wherein: the mixing bin also comprises two coal quantity adjusting valves (3); the basic bin (1) is communicated with a coal quantity adjusting valve (3), the second storage bin (2-1) is communicated with the coal quantity adjusting valve (3), and the two coal quantity adjusting valves (3) are communicated with the blender (4).

5. The W-flame boiler with flexible peak shaving using a reserve bunker as claimed in claim 1, wherein: the coal storage system further comprises a plurality of coal conveying pipelines (6), the first storage bin (2) is communicated with each group of double-cyclone-barrel burners (8) on the boiler body (7) through the coal conveying pipelines (6), and the mixing bin is communicated with each group of double-cyclone-barrel burners (8) on the boiler body (7) through the coal conveying pipelines (6).

6. The W-flame boiler with flexible peak shaving using a reserve bunker as claimed in claim 1, wherein: the coal storage amount of the second storage bin (2-1) is 0.5-0.8 times of the coal storage amount of the basic bin (1), and the daily coal storage amount of the first storage bin (2) is the same as that of the basic bin (1).

7. A boiler peak shaving method using the W-flame boiler with flexible peak shaving using the reserve bunker as claimed in claims 1-6; the method is characterized in that: the method is realized according to the following steps:

the method comprises the following steps: preparation work: poor-quality anthracite and lean coal are stored in the basic bin (1) and the first storage bin (2), and high-quality bituminous coal is stored in the second storage bin (2-1);

step two: and (3) combustion work: starting the boiler body (7) to work;

step three: peak regulation work: the peak shaving work is set according to the requirement, the boiler body (7) is enabled to carry out the peak shaving work by controlling the mass and the type of the pulverized coal entering the boiler body (7) through the first storage bin (2) and the mixing bin, and the peak shaving work of the W flame boiler is further achieved.

8. The boiler peak shaving method of the W-flame boiler using the reserve bunker for peak shaving flexibility as claimed in claim 7; the method is characterized in that: the peak regulation work in the third step is that when the work load of the boiler needs to be more than 60 percent of the rated load work, the second storage bin (2-1) stops working, only the basic bin (1) and the first storage bin (2) supply pulverized coal, and only the pulverized coal supplied by the basic bin (1) and the first storage bin (2) in the boiler body (7) is combusted.

9. The boiler peak shaving method of the W-flame boiler with flexible peak shaving using the reserve bunker as claimed in claim 7: the method is characterized in that: the peak regulation work in the third step is that when the boiler works with 40% -60% rated load, the basic bin (1), the first storage bin (2) and the second storage bin (2-1) work, high-quality coal with 20% -30% of volatile content and low-quality coal are supplied to pulverized coal in proportion, and the pulverized coal in the boiler body (7) is combusted.

10. The boiler peak shaving method of the W-flame boiler with flexible peak shaving using the reserve bunker as claimed in claim 7: the method is characterized in that: the peak regulation work in the third step is that when the boiler works at 20% -40% rated load deep peak regulation work, the basic bin (1) and the first storage bin (2) stop supplying coal powder, the second storage bin (2-1) supplies coal powder, high-quality coal with 30% -40% of volatile content supplies coal powder, and the coal powder in the boiler body (7) burns.