CN212108373U - A circulating fluidized bed boiler for pure burning of high alkali and high chlorine coal - Google Patents

Abstract

The utility model relates to a circulating fluidized bed boiler for pure burning of high alkali and high chlorine coal. The dense phase area of the boiler hearth is provided with a large-pitch light tube and a thick-walled buried tube, and a slag blowing device is arranged at the arch at the lower part of the rear wall of the first flow of the furnace. , there is a brick hanging area on the upper membrane water-cooling wall of the first flow of the furnace, an adjustment baffle is provided at the inertial separation between the second flow of the furnace and the third flow of the furnace, and the connection of the second flow of the furnace and the third flow of the furnace A U-shaped flow channel is arranged at the bottom transition, an overflow device is arranged in the U-shaped flow channel, a cyclone separator is arranged at the third flow outlet of the furnace, and a coal feeder and a bed addition silo are arranged in front of the furnace. Control the operating temperature of the furnace between 750℃-820℃, and according to the change of the air pressure of the return material and the temperature of the furnace, add a number of bed materials from the bed silo to the spiral coal feeder, which can effectively solve the problem of high alkali and high alkali in the boiler. The boiler is forced to shut down due to the contamination and slagging of the heating surface of the chlorine coal, and the long-term, safe and stable operation of the boiler with pure high alkali and high chlorine coal is realized.

Description

A circulating fluidized bed boiler for pure burning of high alkali and high chlorine coal

technical field

The utility model relates to a boiler, in particular to a circulating fluidized bed boiler for pure burning of high-alkali and high-chlorine coal.

Background technique

Xinjiang's coal resources account for 2/5 of China's total coal reserves, up to 2.19 trillion tons, ranking first in the country. 95% of the total resources in the region are concentrated in Zhundong, Tuha and other places. Only Zhundong Coalfield has proven coal reserves of 213.6 billion tons, and Sha'er Lake Coalfield has proven coal reserves of 90 billion tons. Sha'er Lake coal has the advantages of high volatile content (above 30%), medium calorific value (14MJ/kg-19.5MJ/kg), low ash content (below 10%), and low sulfur content (0.2%-0.3%). However, the raw coal is lumpy, easily crushed and weathered, easily ignited and spontaneously ignited, with high moisture (above 20%), low ash melting point (softening temperature of 1180°C), and high sodium content (4% to 12%) in coal. The chlorine content of coal is more than 0.3%, and the highest is more than 1%. Sha'er Lake coal is a typical high-alkali and high-chlorine coal, which has serious slagging and fouling characteristics.

The operating temperature of conventional circulating fluidized bed boilers is generally in the range of 850℃-950℃. Coal particles are suspended and burned in the dense phase zone of the furnace. During the combustion process of coal particles, all the sodium salts in the coal ash will be released and exist in the flue gas in the gas phase. . The flue gas flows upward to the furnace outlet, and flows into the tail flue through the gas-solid separator. The tail flue is generally arranged in sequence with high temperature superheater/high temperature reheater, low temperature superheater/low temperature reheater, economizer, and air preheater. , the furnace outlet temperature is generally 800 ~ 900 ℃, the flue gas flows through the above heating surface to release heat, and the temperature gradually decreases from 800 ~ 900 ℃ to about 150 ℃. When the gas-phase sodium salt contacts the lower temperature heating surface, it condenses and accumulates on the surface of the tube, and absorbs the ultra-fine ash in the flue gas to form a contaminated inner layer. The continuous condensation and capture of fly ash particles in the flue gas make the contamination layer grow continuously, resulting in the thickening of the contamination layer on the pipe wall, which eventually covers the entire pipe wall, and even the entire heating surface will appear "bridging" phenomenon. The contamination layer becomes very hard, and the conventional boiler steam soot can not be removed, so the heat transfer effect of the convective heating surface will be greatly reduced, which directly affects the long-term safe and stable operation of the boiler.

Due to the lack of domestic understanding of burning high-alkali and high-chlorine coal in the early stage, and the lack of engineering operation experience, the boiler design and operation were treated according to ordinary coal quality, so that the boilers that were put into operation after burning high-alkali and high-chlorine coal all appeared The situation that the tail convection heating surface is seriously blocked by the cohesive fouling and forced to stop. Through searching relevant literature and actual investigation, it is found that the cohesive fouling of boilers is mainly concentrated in the high and low temperature superheater, reheater section, tail economizer, air preheater and other convective heating surfaces.

At present, the main methods to solve the above problems include blending combustion, flue gas recirculation and spraying, strengthening soot blowing, and using evaporation screens to cool the tail flue to below 600 °C. Additives to reduce the relative content of sodium in raw coal. This control method can only slow down the contamination, and the sodium compound vapor in the coal will eventually condense on the heating surface tube bundle, which cannot fundamentally solve the problem. When the proportion of external coal blending is too large, the demand for external coal is large. Due to the limitation of transportation conditions, the operating cost is greatly increased, and the additives also have the same problem, which is difficult to apply on a large scale. Flue gas recirculation or spraying is mainly through the mixing of cold flue gas or spray water spray to reduce the flue gas temperature in the area of high temperature heating surface (high over, high over/low over) area.

CN105805736B discloses a circulating fluidized bed boiler and a method for preventing the contamination of its heating surface by alkali metal compounds. No superheater and reheater are arranged in the high temperature zone of the flue at the tail of the boiler, and an evaporation screen is arranged in the flue at the tail to remove the flue gas. The temperature is lowered to below 600 °C; CN207334719U discloses a circulating fluidized bed boiler, which adopts a buried tube and film wall combined heat transfer structure, and reasonably arranges the heating surface to ensure that the inlet smoke temperature of the convective heating surface of the tail shaft is controlled below 530 °C; In principle, the above boilers use the method of cooling, so that the tail convection heating surface avoids the sodium vapor condensation temperature range. However, through the actual operation, it is found that the convection heating surface in the area where the temperature of the tail flue gas is reduced to below 530 °C is also very contaminated with ash (a thick gray wall is formed between the tubes). Loose and porous structure, the particle size of ash deposits ranges from 5 μm to 10 μm, and it is ellipsoid or irregular spherical. The main components are NaCl, MgO, CaSO ₄ , CaCO ₃ and SiO ₂ . These technical means of strengthening soot blowing can only slow down the cohesive soot deposition on the convective heating surface, and do not systematically solve all the characteristics of high-alkali and high-chlorine coal. These unfavorable factors limit the large-scale and high-efficiency utilization of Zhundong and Sha'er Lake coals, resulting in a large number of high-alkali and high-chlorine coals with low mining cost, good combustion activity, low pollution and low emissions not being fully utilized.

At present, it is found from the pure sintering experiment that there are several key problems to be solved in the pure sintering of high-alkali and high-chlorine coal:

1. The problem of contamination and slagging on the rear convection heating surface.

2. The ash melting point is low (ST temperature is not higher than 1180 ℃), the furnace combustion area is stained and coked, and the bed material sticks and agglomerates.

3. The high alkali and high chloride coal has less ash (below 10%), but it is easy to pulverize (fine powder with a particle size of less than 1mm accounts for 40%), and the fly ash concentration after combustion is much higher than that of conventional pulverized coal combustion. The bottom slag is much lower than that of conventional coal, which leads to unsustainable problems such as less and less bed material and reduction of boiler circulation.

Therefore, it is necessary to solve these key problems from the perspective of boiler structure design and operation method.

Utility model content

The technical problem to be solved by the utility model is to provide a circulating fluidized bed boiler that can run stably, safely and reliably for a long period of time.

The technical scheme adopted by the utility model to solve the technical problem is as follows: a circulating fluidized bed boiler of pure caustic high alkali and high chloride coal, comprising a furnace chamber composed of a furnace chamber dense phase zone and a furnace chamber dilute phase zone, and the furnace chamber is provided with The first process of the furnace, the second process of the furnace, the third process of the furnace, and the isobaric air chamber, the dense phase area of the furnace is provided with a large-pitch (preferably ≥ 200mm) light pipe thick-walled buried pipe, and the first process of the furnace is There is a slag blowing device at the arch at the lower part of the back wall, the upper membrane water wall of the first flow of the furnace is provided with a brick hanging area, and the inertial separation between the second flow of the furnace and the third flow of the furnace is provided with a regulating block Plate, a U-shaped flow channel is provided at the bottom connecting transition between the second flow of the furnace and the third flow of the furnace, an overflow device is arranged in the U-shaped flow channel, and the lower part of the overflow pipe of the overflow device is connected with soot. The air duct is provided with a shut-off valve. The third flow outlet of the furnace is provided with a cyclone separator, the convection heating surface in the tail flue is provided with a gas energy shock wave sootblower, a coal feeder is provided in front of the furnace, and a bed-adding silo is provided on the coal feeder.

The furnace adopts a three-flow membrane water-cooled wall structure and a buried pipe is set in the dense phase area of the furnace. The buried pipe must be a thick-walled pipe with a large pitch, (for anti-wear, the conventional circulating fluidized bed buried pipe is equipped with anti-wear fins fins, which will aggravate fouling and slagging). A large number of heating surfaces are arranged in the furnace with a light and thick-walled buried pipe, mainly to control the furnace outlet temperature below 550 °C, and to condense and precipitate the sodium compound vapor in the flue gas on the heating surface of the furnace (buried pipe and membrane water wall). , The furnace flue gas is used for strong scouring to realize the dynamic balance of contamination and slagging on the heating surface, and prevent the tail heating surface from being polluted by sodium compounds and cause cohesive ash deposition.

Further, the pitch between the thick-walled buried pipes of the adjacent light pipes in the dense phase area of the furnace is ≥200 mm.

Further, a slag blowing device is arranged on the rear wall of the first flow of the furnace, and the slag blowing device comprises a purging nozzle, a purging master pipe and a purging gap, and half of the purging nozzle is embedded in the lower part of the rear wall of the first flow. In the pouring material at the arch of the furnace, a purging gap is set on the nozzle; the purging main pipe is installed outside the furnace and connected to the hot air pipe, and is connected with the purging nozzle through the connecting pipe. The slag blowing device uses hot air to form an air curtain, which continuously blows.

Further, pins for fixing refractory bricks are arranged in the membrane-type water-cooled wall-hanging brick area. The refractory bricks cover the heating surface of the membrane-type water-cooling wall. By adjusting the number of fixed refractory bricks, the heating area of the membrane-type water-cooling wall can be adjusted flexibly and conveniently.

Further, an adjustment baffle is provided at the inertial separation between the second flow of the furnace and the third flow of the furnace. The adjustment baffle is a movable baffle, and the swinging angle of the baffle can be flexibly adjusted according to the operating conditions.

Further, the lower part of the overflow device is provided with an air chamber, and the air chamber is connected with a return air duct. The air chamber is provided with an air distribution plate and an air cap, and each air cap has 10 openings on the front side of the air cap furnace and 8 openings on the rear side of the furnace.

Further, the upper part of the overflow device is divided into two U-shaped grooves by a tongue-shaped plate.

Further, the overflow pipe of the overflow device and the lower part of the return pipe are equipped with an ash seeding pipe, and the ash seeding pipe is equipped with two stop valves, which can flexibly adjust the ash seeding air volume. The ash sowing air is used to blow away the overflow ash and the returning ash to prevent coking caused by accumulation on the furnace air distribution board.

Further, a superheater, an economizer, a denitration device and an air preheater are arranged in the tail flue, and a gas energy shock wave sootblower is installed on the convection heating surface.

Further, the superheaters are arranged in series to increase the pitch between the tube bundles.

Further, the air preheater is a horizontal air preheater.

The main purpose of adding bed material is to achieve the following two purposes:

1. Increase the amount of ash circulating in the furnace, take away the heat in the dense phase area of the furnace in time, and ensure that the temperature of the furnace is kept between 750 °C and 820 °C.

2. Continuously replace the existing bed material with high sodium compound content in the furnace by adding bed material from time to time to prevent the bed material from further reducing the ash melting point and causing adhesion, agglomeration and slag.

The utility model utilizes the three-flow membrane type water-cooling wall and the thick-walled buried pipe of the large-pitch light pipe to reduce the temperature of the flue gas to below 550 DEG C. The process membrane water-cooling wall will be completely precipitated, and under the self-cleaning effect of the strong scouring of the flue gas material in the furnace, the contamination and slagging will reach a dynamic balance and no longer deteriorate; in addition, by controlling the furnace temperature and adding bed material irregularly. , to solve the problem of the furnace bed material adhesion and agglomeration slag and ash circulation. In this way, it not only solves the problem of continuous deterioration of fouling and slagging in the furnace, but also solves the problem of fouling and slagging on the tail convection heating surface, so as to realize the safe, stable and long-term operation of the high-alkali high-chloride coal boiler.

Description of drawings

Fig. 1 is the structural representation of the utility model circulating fluidized bed boiler embodiment;

Fig. 2 is the structural representation of the overflow device in the embodiment shown in Fig. 1;

FIG. 3 is a schematic structural diagram of the slag blowing device in the embodiment shown in FIG. 1 .

In the accompanying drawings: 1-furnace, 101-furnace dense phase zone, 102-furnace dilute phase zone, 103-smooth pipe thick-walled buried pipe, 2-slag blowing device, 201-purging nozzle, 202-purging seam, 203-connecting pipe, 204-purging main pipe, 3-adjusting baffle plate, 4-furnace first process, 5-furnace second process, 6-furnace third process, 7-brick hanging area, 8-cyclone separator , 9- gas shock wave soot blower, 10- superheater, 11- economizer, 12- SCR denitration device, 13- horizontal air preheater, 14- U-shaped flow channel, 15- overflow device, 1501 -Intake duct, 1502-air chamber, 1503-air distribution plate, 1504-air cap, 1505-tongue plate, 1506-first U-shaped groove, 1507-second U-shaped groove 2, 1508-overflow pipe, 16 -Hot air duct, 17-deflector, 18-slag drop pipe, 19-isobaric air chamber, 20-furnace air distribution plate and air cap, 21-coal drop pipe, 22-returner, 23-ash sowing pipe, 24-stop valve, 25-screw coal feeder, 26-adding bed silo, 27-furnace front coal bunker

Detailed ways

The present utility model will be described in further detail below with reference to the accompanying drawings and specific embodiments.

As shown in Figures 1-3, the embodiment of the circulating fluidized bed boiler of the present invention includes a furnace chamber 1 composed of a furnace chamber dense phase zone 101 and a furnace chamber dilute phase zone 102, and the furnace chamber is provided with a first furnace chamber flow 4 and a second furnace chamber. Process 5 and the third process 6 of the furnace, the isobaric air chamber 19, the dense phase area of the furnace is provided with a large-pitch (200mm) light pipe thick-walled buried pipe 103, the arch of the lower part of the rear wall of the first process 4 of the furnace A slag blowing device 2 is provided at the shape, a brick hanging area 7 is provided on the upper membrane-type water-cooled wall of the first process 4 of the furnace, and the inertial separation between the second process 5 of the furnace and the third process 6 of the furnace is provided with adjustment The baffle 3, the bottom connecting transition between the second flow 5 of the furnace and the third flow 6 of the furnace is provided with a U-shaped flow channel 14, and the U-shaped flow channel 14 is provided with an overflow device 2, and the third flow of the furnace 6 A cyclone separator 8 is installed at the outlet, and a gas energy shock wave sootblower 9 is installed on the convective heating surface in the tail flue. The upper part of the coal feeder 25 is installed in front of the furnace. A bed bunker 26 and a coal bunker 27 in front of the furnace are installed.

The buried pipe in the dense phase zone 101 of the furnace adopts the thick-walled buried pipe 103 of the large-pitch light pipe, with a vertical clear distance of 200mm and a horizontal clear distance of 300mm. In view of the low melting point and sodium salt adhesion of high-alkali and high-chlorine coal, the material is very easy to be deposited in the furnace. The buried pipes with anti-wear devices will accumulate agglomeration, which will cause coking and slagging. For this reason, thick-walled pipes are used, and the flow rate between the buried pipes 103 with thick-walled smooth pipes is reduced, so as to achieve the anti-wear effect.

The furnace 1 adopts a three-flow membrane type water-cooled wall structure and a large-pitch light pipe thick-walled buried pipe 103 is arranged in the dense phase region 101 of the furnace. A large number of heating surfaces are arranged in the furnace 1, mainly to control the outlet temperature of the furnace 1 below 550 ℃, and to condense the sodium compound vapor in the flue gas on the heating surface of the furnace (buried pipe and membrane water wall), The furnace flue gas is used for strong scouring to achieve dynamic balance of contamination and slagging. Prevent the tail heating surface from being contaminated by sodium compounds and cause cohesive fouling. The full-film water-cooled hearth increases the burning time, improves the combustion efficiency, and reduces the outlet temperature of the hearth.

The high alkali and high chloride coal enters the furnace through the coal drop pipe 21, and is suspended and burned in the furnace dense phase area 101 with the hot air from the isobaric air chamber 19 and through the furnace air distribution plate and the air cap 20, and the temperature of the furnace dense phase area 101 is controlled at 750 ℃ At -850℃, the sodium compound in the coal is sublimated into the sodium compound vapor in the dense phase zone of the furnace, which is merged into the high temperature flue gas. The membrane type water wall and the thick wall of the light pipe of the three processes are buried on the thick-walled pipe 103, resulting in slagging and fouling. However, since the buried pipe and the membrane water-cooled wall are smooth and suspended vertically, the flue gas continuously scours the vertical membrane-type water-cooled wall and the thick-walled buried pipe 103 of the bare pipe, so that the buried pipe and the membrane-type water-cooled wall are fouled and slugged to achieve a dynamic balance.

The coal falling pipe 21 is the front wall of the first flow 4 of the furnace on the side of the furnace 1, and the back wall of the first flow 4 of the furnace is on the opposite side. Since the bed material in the dense phase zone 101 of the furnace contains a large amount of sodium compound steam, it is easy to be trapped in the first flow of the furnace. A large slag lump is formed in the arch at the lower part of the rear wall of the first process 4, which falls into the furnace and causes the fluidization to deteriorate. The slag blowing device 2 is set here. The slag blowing device is composed of a purging nozzle 201, a purging main pipe 204, a connecting pipe 203 and a purging slot 202. The purging nozzle 201 is half embedded in the back wall of the first flow 4 of the furnace. In the casting material at the lower arch, a purge slot 202 is set on the purge nozzle 201; The slag blowing device 2 uses hot air to form an air curtain, and it is continuously blown and blown away before the slag is formed.

Dowels for fixing refractory bricks are provided in the brick hanging area 7 . The outlet temperature of the first flow 4 of the furnace has a great influence on the burning of the fuel and the safe operation of the heating surface at the back. Dowels are reserved on the water-cooling wall for fixing the refractory bricks, and the refractory bricks cover the heating area of the membrane-type water-cooling wall, which is flexible and convenient to adjust the heating area.

An adjustment baffle 3 is set at the inertial separation between the second flow 5 of the furnace and the third flow 6 of the furnace to accurately adjust the first-stage separation efficiency, on the one hand to ensure that the bed temperature runs between 750-820 °C; The separation efficiency of the rear cyclone separator is optimal.

A U-shaped flow channel 14 is provided at the bottom connecting transition between the second flow of the furnace and the third flow of the furnace. The U-shaped flow channel 14 is provided with an overflow device 15, and the lower part of the overflow device 15 is provided with an air chamber 1502, The air chamber 1502 is provided with an air distribution plate 1503 and an air cap 1504. The upper part of the overflow device 15 is divided into a first U-shaped groove 1506 and a second U-shaped groove 1507 by the tongue plate 1505. The air chamber 1502 An air intake duct 1501 is externally connected, and the return air is connected to the air chamber 1501 through the air intake duct 1502 . The opening area of the air cap on the side of the first U-shaped groove 1506 is slightly smaller (8 holes per air cap), and the air volume at this place is used to fluidize the materials collected by the U-shaped flow channel 14. The opening area of the second U-shaped groove 1507 is larger. (10 holes per air cap), the air volume here is used to transport the material to the overflow pipe 1508 and enter the furnace 1 to burn again. After the low-melting high-alkali and high-chlorine coal is burned, it is collected at the U-shaped flow channel 14 through the inertia separation of the second flow 5 and the third flow 6 of the furnace, and it is easy to cause blockage and poor material return, and an overflow device is set here. 2. It can effectively solve the problems of material accumulation, blockage and poor return of materials here.

The overflow pipe 1508 has a large amount of ash returned, which is easy to accumulate on the furnace air distribution plate and cause coking. Therefore, an ash seeding pipe 23 is installed at the lower part of the overflow pipe 1508. The ash seeding pipe 23 is connected from the hot air duct 16, and two cut-off pipes are set The valve 24 is used to flexibly adjust the air volume for sowing ash. The ash returned by the overflow pipe 1508 is dispersed by the ash-spreading wind, so that it returns to the furnace air distribution plate 20 evenly.

After the high-alkali and high-chlorine coal is burned, the slag with a large specific gravity is deposited on the furnace air distribution plate and the air cap 20 in the dense phase zone 101 of the furnace, and is discharged from the furnace through the slag drop pipe 18, and the coal powder and ash with light specific gravity pass through the flue gas. The second flow 5 of the furnace and the third flow 6 of the furnace are separated by inertia, a part is collected at the U-shaped flow channel 14, and the other part is separated by the 550°C cyclone 8 and directly enters the furnace 1 through the return pipe of the return device 22. Burn again. The flue gas without sodium compound steam enters the tail flue after passing through the cyclone separator 8; the tail flue is provided with a superheater 10, an economizer 11, an SCR denitration device 12 (ie a selective catalytic reduction denitration device) and a horizontal type Air preheater 13, gas energy shock wave sootblowers 9 are respectively installed on the convection heating surface; after the high temperature flue gas exchanges heat with the convection heating surface, the flue gas temperature drops to 135°C and then goes to the boiler outlet. The induced draft fan is sucked out to the chimney and discharged into the atmosphere. The gas energy shock wave soot blower 9 performs shock wave soot blowing on the convective heating surface in a 360-degree angle without dead angle, and blows it once every 2 hours, which can effectively prevent viscous dust from bridging and accumulating.

The air preheater adopts a large-pitch horizontal air preheater 13 (practice has proved that for viscous ash, the vertical tubular air preheater is easy to be blocked, but the horizontal air preheater will not be blocked), and is installed. A gas energy shock wave sootblower 9 is provided to prevent the air preheater from being blocked.

The air preheated by the horizontal air preheater 13 is sent to the isobaric air chamber 19 of the furnace through the hot air duct 16. The hot air duct 16 is provided with a deflector 17 near the isobaric air chamber 19. When the hot air enters the isobaric air chamber 19, it is more uniform, laying a solid foundation for the fluidized bed material.

The operation method of the boiler is as follows. The operating temperature of the furnace is strictly controlled between 750 ° C and 820 ° C. The high volatile content of high alkali and high chloride coal is easy to catch fire, but the ash melting point is low, which can avoid bed material adhesion and agglomeration. In addition, pay close attention to the changes in the air pressure of the returned material, the furnace temperature and the differential pressure of the furnace. Once the temperature of the furnace exceeds the standard, or the air pressure of the returned material is low, the bed material should be added from the bed silo in time. The bed material must be non-high alkali. The slag produced by high chlorine coal has a particle size of not more than 5mm and a bulk density of not more than 1250kg/m ³ . The amount of bed material added is determined according to the two indicators of furnace temperature and return air pressure returning to normal.

The main purpose of adding bed material is to achieve the following two purposes:

1. Increase the amount of ash circulating in the furnace, take away the heat in the dense phase area of the furnace in time, and ensure that the temperature of the furnace is kept between 750 °C and 820 °C.

2. Continuously replace the existing bed material with high sodium compound content in the furnace by adding bed material from time to time to prevent the bed material from further reducing the ash melting point and causing adhesion, agglomeration and slag.

The 45t/h circulating fluidized bed boiler of a chemical plant in Xinjiang adopts the circulating fluidized bed boiler and the operation method of the utility model. The circulating fluidized bed boiler burns pure high-alkali and high-chlorine coal (Sha'erhu coal), and adopts a 2-stage crushing system. , the particle size of raw coal is controlled within 10mm, the bed material does not use the slag produced by the boiler itself, and the slag after combustion of non-high alkali and high chloride coal is purchased from nearby, and the particle size of the bed material is controlled to be less than 5mm and the bulk density is not more than 1250kg/m ³ , Strictly control the furnace temperature in the range of 750℃-820℃. When the furnace temperature exceeds 820℃, add about 100kg of bed material to the furnace through the bed silo 26 on the screw feeder 25 to reduce the furnace temperature. The air pressure of the material is also a very important indicator. When the air volume of the return material is lower than 3.1kPa, the bed material must also be added to the furnace. According to the actual operation experience, the boiler consumes about 140t of high-alkali and high-chlorine coal (Sha'er Lake coal) a day. The amount of bed material added every day is about 500kg. The pulverized coal in the boiler furnace is completely burned, the bed material is well fluidized, the overflow device returns smoothly and evenly, and there is no slagging at the arch of the back wall of the first process after the slag blowing pipe is injected. The main economic and technical indicators of the boiler during the assessment period are shown in the following table:

Main economic and technical indicators of boilers

该循环流化床锅炉实现了高碱高氯煤的纯烧和长周期运行，截止目前，该锅炉持续运行时间已经超过100天。

The circulating fluidized bed boiler has achieved pure combustion and long-term operation of high-alkali and high-chlorine coal. Up to now, the boiler has been running continuously for more than 100 days.

The utility model utilizes the three-flow membrane type water-cooling wall and the thick-walled buried pipe of the large-pitch light pipe to reduce the temperature of the flue gas to below 550 DEG C. The process membrane water-cooling wall will be completely precipitated. Under the self-cleaning effect of the strong scouring of the furnace flue gas material, the contamination and slagging will reach a dynamic balance and will not deteriorate. In addition, by controlling the furnace temperature and adding bed material irregularly. , to solve the problem of the furnace bed material adhesion and agglomeration slag and ash circulation. In this way, it not only solves the problem of continuous deterioration of fouling and slagging in the furnace, but also solves the problem of fouling and slagging on the convection heating surface of the tail, so as to realize the safe, stable and long-term operation of the high-alkali and high-chlorine coal-fired boiler.

Those skilled in the art can make various modifications and variations to the present utility model, if these modifications and variations are within the scope of the claims of the present utility model and its equivalent technology, then these modifications and variations are also within the protection scope of the present utility model. Inside.

The content not described in detail in the specification is the prior art known to those skilled in the art.

Claims (9)

1. The utility model provides a circulating fluidized bed boiler of high chlorine coal of soda is burnt to pure, includes the furnace that comprises furnace dense phase district and furnace dilute phase district, furnace is equipped with first process of furnace, furnace second process and furnace third process, isobaric plenum, its characterized in that: the device comprises a hearth dense-phase area, a large-pitch light pipe thick-wall buried pipe, a slag blowing device, a brick hanging area, a U-shaped flow channel, an overflow device, a cyclone separator, a tail flue, a convection heating surface, a coal feeder and a bed feeding bin, wherein the large-pitch light pipe thick-wall buried pipe is arranged in the hearth dense-phase area, the slag blowing device is arranged at the arch position of the lower portion of a rear wall of a first flow of the hearth, the membrane type water-cooling wall of the first flow of the hearth is provided with the brick hanging area, the U-shaped flow channel is arranged at the connecting transition position of the bottom of a second flow of the hearth and the bottom of.

2. The circulating fluidized bed boiler for burning soda-rich and high-chlorine coal as claimed in claim 1, wherein: the dense-phase region of the hearth is internally provided with buried pipes, the buried pipes adopt light pipe thick-wall pipes, and the pitch between the two adjacent light pipe thick-wall buried pipes is more than or equal to 200 mm.

3. The circulating fluidized bed boiler for burning soda-rich and high-chlorine coal as claimed in claim 1, wherein: and pins for fixing refractory bricks are arranged on the membrane water-cooled wall of the brick hanging area.

4. The circulating fluidized bed boiler for burning soda-rich coal according to any one of claims 1 to 3, wherein: an air chamber is arranged at the lower part of the overflow device, and a material returning air pipe is externally connected to the air chamber; the air chamber is provided with an air distribution plate and an air cap, and the upper part of the overflow device is divided into two U-shaped grooves by a tongue-shaped plate.

5. The circulating fluidized bed boiler for burning soda-rich and high-chlorine coal as claimed in claim 4, wherein: each blast cap is provided with 10 holes at the front side of the hearth and 8 holes at the rear side of the hearth.

6. The circulating fluidized bed boiler for burning soda-rich coal according to any one of claims 1 to 3, wherein: an ash sowing air pipe is arranged at the lower part of an overflow pipe of the overflow device.

7. The circulating fluidized bed boiler for burning soda-rich coal according to any one of claims 1 to 3, wherein: and an adjusting baffle is arranged at the inertia separation position between the second flow and the third flow of the hearth.

8. The circulating fluidized bed boiler for burning soda-rich and high-chlorine coal as claimed in claim 5, wherein: and an adjusting baffle is arranged at the inertia separation position between the second flow and the third flow of the hearth.

9. The circulating fluidized bed boiler for burning soda-rich and high-chlorine coal as claimed in claim 6, wherein: and an adjusting baffle is arranged at the inertia separation position between the second flow and the third flow of the hearth.

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