CN210373405U

CN210373405U - Vertical pulverized coal boiler

Info

Publication number: CN210373405U
Application number: CN201921039705.9U
Authority: CN
Inventors: 赵慧武; 马登斌; 江维光; 付存厚; 马金忠
Original assignee: Bg Clean Thermal Co ltd
Current assignee: Bg Clean Thermal Co ltd
Priority date: 2019-07-04
Filing date: 2019-07-04
Publication date: 2020-04-21
Anticipated expiration: 2029-07-04

Abstract

An embodiment of the utility model provides a vertical pulverized coal boiler, this vertical pulverized coal boiler include furnace and shaft flue, and furnace's water-cooling wall is hugged closely to the shaft flue. The utility model discloses vertical pulverized coal boiler simple structure, the leakproofness is good.

Description

Vertical pulverized coal boiler

Technical Field

The utility model relates to a boiler technical field especially relates to a vertical pulverized coal fired boiler.

Background

The energy resource of China is characterized by rich coal, lack of oil and little gas. This means that coal will be the leading factor of our energy structure both at present and for a considerable period of time in the future. However, the current state of the coal-fired industrial boiler in China is not optimistic.

Firstly, the pollution is serious. The data show that in 2010, the coal of the Chinese industrial boiler discharges about 1000 million tons of sulfur dioxide, about 200 million tons of nitrogen oxides, about 100 million tons of dust and about 9000 million tons of waste residues, and is the second largest coal smoke type pollution source next to coal-fired power generation in China. However, in the chinese industrial boiler, more than 85% of the total number and the total capacity are coal-fired industrial boilers.

Secondly, the energy efficiency level is low. According to statistics, the design efficiency of the coal-fired industrial boiler is generally 72% -80%, the actual operation thermal efficiency is mostly 60% -65%, and the difference from the international level is 15-20 percentage points.

And thirdly, the automation level is low. Most coal-fired boilers are still manually operated by workers, the operating environment is severe, and the actual operation efficiency is poor.

The twelve-five energy-saving emission-reduction target indicates that by 2015, the total energy consumption of the national ten thousand yuan domestic production is reduced to 0.869 ton of standard coal (calculated according to 2005), which is 16% lower than 1.034 ton of standard coal in 2010 and 32% lower than 1.276 ton of standard coal in 2005. If the overall thermal efficiency of an industrial boiler is improved from 65% to 80%, more than 1.3 million tons of coal can be saved each year. The national institute of energy improvement and development committee indicates that the korean science of the long term has great potential for energy conservation in industrial boilers as "the joint business of china".

Under the background of the current market situation, the energy saving performance of the novel pulverized coal industrial boiler is highlighted. 863 ministry of science and technology, the expert Deminghua in the advanced energy technology field, to the Chinese United states Commission, shows that pulverized coal particles are uniform, and are combusted in suspension in air, and compared with stratified combustion, the proportion of combustion air is low, the burnout rate is high, and the heat loss of smoke emission is small; the pulverized coal industrial boiler adopts the totally-enclosed powder feeding, air supplying and ash discharging technology, has good heat preservation performance, greatly reduces the heat loss caused by hot air and smoke leakage, and is beneficial to improving the heat efficiency of the boiler; the traditional industrial boiler (such as a chain boiler) adopts slow-burning stewing operation under intermittent load, so that fuel waste is caused, the pulverized coal industrial boiler can be started and stopped immediately, and the fuel loss during stewing is reduced.

In the published survey of the "strategic emerging industry key products and service guide catalogues" compiled by the national development and improvement committee, "precision powder supply, rapid ignition and stable combustion, low-nitrogen combustion, clean pressure-bearing hearth without ash deposition, high-efficiency and low-resistance bag-type dust removal, combined integration of ash-calcium flue gas desulfurization, automatic control of whole-process linkage protection, and other distributed high-efficiency pulverized coal combustion technologies and equipment" are listed in the first industry of the seven industries in the catalogues, "energy-saving and environment-friendly industry, high-efficiency and energy-saving boiler and kiln" appear at the significant position of the first section and are described in detail.

The traditional pulverized coal fired boiler is limited in various aspects such as a burner and environmental protection, and most of the traditional pulverized coal fired boiler is only applied to power plants and large-scale chemical enterprises. The pulverized coal boiler is provided with concentrated pulverized coal supply; the working environment is relatively good; the start and stop of the boiler are simple; the measurement and control level is higher; high efficiency, energy saving, land saving and the like. However, compared with other types of boilers, the high efficiency of the pulverized coal boiler also brings a corresponding high pollution problem, and the miniaturization of the burner is also a factor for limiting the miniaturization of the pulverized coal boiler, so that the pulverized coal boiler has not been widely popularized in the past decades.

Nowadays, environmental protection equipment in the boiler industry is mature day by day, the technology of a combustor is also developed, the pulverized coal pulverizing realizes the concept of 'no coal fired' urban and off-city pulverizing, and the popularization of high-efficiency pulverized coal boilers is also facing to the emerging development. Meanwhile, the method is a challenge for the traditional high-efficiency pulverized coal boiler, and the market competition of the high-efficiency pulverized coal boiler is increased.

The pulverized coal furnace is a suspension combustion furnace using pulverized coal as fuel. The hearth is a large space surrounded by water-cooled fireplace walls, and pulverized coal and air which are ground are mixed by a burner and then sprayed into the hearth for combustion. The combustion of pulverized coal is divided into a preparation stage, a combustion stage and a burnout stage before ignition. Correspondingly, the furnace can be divided into three areas: an ignition zone, a combustion zone and a burnout zone. If the three areas are at the same level, they are conventionally called vertical pulverized coal boilers.

The pulverized coal boiler is suitable for various coals, coal grinding equipment and a corresponding dust removal device need to be arranged, the organization of the combustion working condition is complex, and factors influencing the combustion stability are more. The fly ash of the pulverized coal furnace is as high as 80-90%, and a high-efficiency dust removal device is required.

The high-efficiency pulverized coal boiler is a novel coal-fired boiler taking a pulverized coal combustion technology as a core. The impurities of the pulverized coal ground to the fineness of 200 meshes are fully removed in the grinding process; the fire coal has fine granularity, easy ignition and high volatile value, and can improve the burnout rate; the ash content of the fire coal is low, and the dust removal load can be reduced. The flue gas treated by matched desulfurization, denitration and dust removal equipment meets the national environmental protection standard.

The horizontal flue furnace wall of furnace outlet of the existing vertical pulverized coal boiler has potential safety hazard: the horizontal section of the furnace outlet arranged in the pi shape is generally provided with a superheater to change saturated steam into superheated steam. The surrounding wall superheaters are generally arranged around the horizontal flue and the turning chamber, so that the problems of thermal expansion and sealing of the part are well solved, and the arrangement is classically called. The industrial boiler is mostly used for heating or industrial production, only saturated steam or high-temperature hot water is generated by the boiler, a superheater is not needed, a horizontal flue and a steering chamber cannot be protected by a heating surface, the structure is very complex no matter a steam boiler or a hot water boiler is provided with the heating surface, the steam-water resistance is large, the compensation is not realized, only a heat insulation guard plate structure is adopted, the expansion and sealing of the boiler are difficult to solve at the smoke temperature of 850 ℃, potential safety hazards exist, and the long-term stable operation of the boiler is influenced.

SUMMERY OF THE UTILITY MODEL

The utility model provides a vertical pulverized coal boiler can solve the boiler structure complicacy among the prior art, the poor problem of leakproofness.

In order to solve the technical problem, the utility model discloses a technical scheme be: the vertical pulverized coal boiler comprises a hearth and a vertical shaft flue, wherein the vertical shaft flue is tightly attached to a water-cooled wall of the hearth.

Wherein, the afterbody of shaft flue is equipped with diaphragm type wall enclosed construction for seal shaft flue is in order to avoid the air leakage.

The vertical pulverized coal boiler also comprises a burner, the burner is connected with the hearth, and the burner is a mixed flow burner comprising direct flow and rotational flow.

The mixed flow type combustor is provided with four-stage graded air distribution, and the four-stage graded air distribution comprises three-stage beam-shaped rotational flow and one-stage direct current jet flow.

Wherein, the combustor is two, and two combustors are to the setting of dashing.

The hearth adopts four-face membrane type water-cooled walls, the upper part of the hearth is a combustion chamber, and the lower part of the hearth is used for cooling a cold ash hopper of ash and slag.

Wherein, a slag outlet and a slag outlet door are arranged below the cold ash bucket, and the slag outlet door is connected with a mechanical slag conveyor.

The vertical pulverized coal boiler also comprises a slag condensing tube bundle and a steering chamber, wherein the slag condensing tube bundle is connected with the combustion chamber, and the steering chamber is connected with the slag condensing tube bundle.

Wherein, the shaft flue includes convection bank, and convection bank is connected with the room that turns to.

Wherein, the shaft flue still includes SCR denitrification facility, and SCR denitrification facility locates the below of shaft flue and is connected with convection bank.

The embodiment of the utility model provides a vertical pulverized coal boiler forms II type through hugging closely the shaft flue with furnace's water-cooled wall, does not have horizontal flue, compares in prior art II type, the utility model discloses a vertical pulverized coal boiler simple structure, the leakproofness is good.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained without inventive work, wherein:

FIG. 1 is a schematic structural view of a vertical pulverized coal boiler according to an embodiment of the present invention;

fig. 2 is a schematic top view of the vertical pulverized coal boiler shown in fig. 1.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work all belong to the protection scope of the present invention.

Referring to fig. 1 and 2, fig. 1 is a schematic front view of a vertical pulverized coal boiler according to an embodiment of the present invention, and fig. 2 is a schematic top view of the vertical pulverized coal boiler shown in fig. 1. The vertical pulverized coal boiler of the present embodiment includes a burner 10, a furnace 20, a clinker tube bundle 30, a shaft flue 40, a drum 50, and a shell 60.

The burner 10 of the present embodiment is a mixed flow burner 10 including a straight flow and a swirling flow, and the mixed flow burner 10 has a four-stage staged air distribution including a three-stage bundled swirling flow and a one-stage straight flow jet. The mixed-flow burner 10 is characterized in that the pulverized coal flame is short, and the flame burnout process is completed in a short distance. Therefore, the boiler furnace 20 can be relatively arranged in a short way, the occupied area of the boiler is reduced, the steel consumption of the boiler is less, and the manufacturing cost of the boiler is reduced. The combustor 10 of this embodiment is preferred two, and two combustors 10 adopt the hedging to arrange, and two hedging flame's combustor 10, the department flame overlaps in the middle of the boiler, because revolve to the same, two strands of rotatory air current superposes, has accelerated rotatoryly, has played the enhancement to the later stage mixture, and the burn-out rate has improved, has increased the efficiency of boiler.

The hearth 20 is connected with the combustor 10 and adopts a four-face membrane type water-cooled wall. The upper part of the hearth 20 is a combustion chamber 21, the lower part of the hearth 20 is provided with a cold ash hopper 22 for cooling ash, the combustion chamber 21 is approximately rectangular, and pulverized coal is combusted in the combustion chamber 21 and generates high-temperature flue gas. The cold ash bucket 22 is a bucket formed by a cold water wall, and in the embodiment, the inclination angle of the bucket 22 is preferably 35 °. Of course, in other embodiments, the angle may be 40 ° or 50 °, which is not limited by the present invention. Due to the inclined cold ash hopper 22, the coal ash generated by combustion can be discharged along the cold ash hopper 22, and no ash deposit is formed in the hearth 20.

Preferably, a slag outlet and a slag outlet door are further arranged below the cold ash bucket 22, the slag outlet door is further connected with a mechanical slag conveyor, coal ash generated by combustion is discharged through the slag outlet and the slag outlet door, and the coal ash is further uniformly fished out by the mechanical slag conveyor, so that the labor intensity of ash removal and slag discharge of operating workers is reduced.

The slag condenser tube bundle 30 is connected with the combustion chamber 21, and the high-temperature flue gas generated by the combustion chamber 21 generates heat exchange in the slag condenser tube bundle 30. In this embodiment, the vertical pulverized coal boiler further comprises a turning chamber, the turning chamber is connected with the slag condensing tube bundle 30, and the turning chamber is used for turning the flue gas after cooling the slag condensing tube bundle 30 and transferring the flue gas to a convection heating surface.

The shaft flue 40 is tightly attached to the water-cooled wall of the furnace 20. The tail part of the vertical shaft flue 40 is provided with a membrane wall sealing structure for sealing the vertical shaft flue 40 to avoid air leakage. The vertical flue 40 and the hearth 20 form a II type, and no horizontal flue exists. The shaft flue 40 comprises a convection bank 41 and an SCR denitration device 42, the convection bank 41 is connected with the steering chamber, and the SCR denitration device 42 is arranged below the shaft flue 40 and connected with the convection bank 41.

Preferably, the vertical pulverized coal fired boiler of the embodiment further comprises a boiler shell 60, the boiler shell 60 is arranged outside the furnace 20 and connected with the SCR denitration device 42, and a threaded smoke pipe with a first stroke and a second stroke is arranged in the boiler shell 60, so as to facilitate sufficient heat exchange on the flue gas.

The drum 50 is disposed between the firebox 20 and the shell 60, and in this embodiment, there is one drum 50. The drum 50 is connected to the lower header of the furnace 20 through a downcomer provided at the lower portion of the drum 50.

Preferably, the vertical pulverized coal boiler may further include an air preheater, an induced draft fan, and a chimney. The air and the high-temperature flue gas can form heat exchange in the air preheater, and the draught fan and the chimney are connected with the threaded smoke pipe in the second stroke and used for leading out the denitrated flue gas and discharging the denitrated flue gas through the chimney.

The main structure of the vertical pulverized coal boiler is introduced above, and the operation of the vertical pulverized coal boiler is described below with reference to fig. 1-2.

The total air quantity of the boiler is divided into primary air and secondary air, the primary air conveys pulverized coal to the pulverized coal burner 10, the secondary air enters the pulverized coal burner 10 through an air preheater (if any), rotates and mixes in the burner 10, organizes pulverized coal to catch fire, and blows into the hearth 20. The flue gas moves upwards along the central line direction of the hearth 20, and continues to burn and release heat. The flue gas cooled by the water-cooled wall of the hearth 20 enters the slag condensing tube bundle 30 at the outlet of the hearth 20, then turns 90 degrees, enters the convection tube bundle 41, and then enters the SCR denitration device 42, and the denitrated flue gas enters the boiler shell 60 (with two strokes in total), finally enters the air preheater (if any), and is discharged into a chimney through the induced draft fan.

The utility model discloses a vertical pulverized coal boiler has following advantage:

1. adopting a high-efficiency low-nitrogen pulverized coal burner: the burner is a mixed-flow type high-efficiency low-nitrogen pulverized coal burner with rich and lean combustion, four-stage graded air distribution (three-stage beam-shaped cyclone + one-stage direct current jet), cyclone and direct current, and has the outstanding characteristics that the pulverized coal flame is short, and the flame burnout process is completed in a short distance. Therefore, the boiler furnace can be relatively arranged in a short way, the occupied area of the boiler is reduced, the steel consumption of the boiler is less, and the manufacturing cost of the boiler is reduced.

2. The combustor adopts both sides wall offset to arrange, improves the boiler and fires the ashes rate, increases boiler efficiency: at present, all high-efficiency pulverized coal industrial boilers adopt rotational flow pulverized coal burners, and the high-efficiency pulverized coal industrial boilers are characterized in that the early-stage air-powder mixing is strong, the later-stage air-powder mixing is weakened due to the rapid attenuation of wind rotation, the burnout degree is poor, and the boiler efficiency is reduced. Adopt the offset to arrange, two burners of offset flame, locate the flame at the boiler middle part and overlap, because revolve to the same, two strands of rotatory air current superposes, have accelerateed rotatoryly, have played the enhancement to the later stage mixture, and the burn-out rate has improved, has increased the efficiency of boiler.

3. The tail convection heating surface adopts a full-film wall closed structure, so that air leakage is reduced, and the boiler efficiency is improved.

4. SCR is conveniently arranged: in the tail shaft flue, the space can be reserved at will according to the requirements of users, SCR can be conveniently arranged in the tail shaft flue, and the denitration catalyst arrangement problem is solved from the design angle.

5. Furnace adopts cold ash bucket structure, makes things convenient for the deashing ash removal: the hearth consists of four membrane walls, the lower parts of the left and right side wall membrane water-cooled walls are inclined inwards by 35 degrees to form a cold ash bucket structure, the cold ash bucket structure is a mature typical structure commonly used by a power station pulverized coal boiler, and fly ash can only naturally slide down and can not be accumulated when falling on the cold ash bucket structure. According to the length of the hearth, a plurality of square ash falling hoppers are finally formed, and the lower parts of the ash falling hoppers are provided with slag outlets, slag doors and mechanical slag conveyors, so that the labor intensity of ash removal and slag discharge of operating workers is reduced.

6. The coal quality is stable, and the boiler operation stability is good: one reason that the traditional coal-fired industrial boiler has low efficiency is that the source of the coal-fired is unstable, and the boiler cannot adjust parameters such as air quantity in time according to the coal quality condition. The efficient industrial pulverized coal boiler adopts centralized powder making, the coal quality source is stable, and the boiler can be ensured to stably run for a long time.

7. The boiler efficiency is high: because the coal quality is stable, the pulverized coal is stably and fully combusted, the boiler efficiency can reach 92 percent, and the coal can be saved by 30 to 50 percent compared with the traditional coal-fired boiler;

8. energy conservation: the frequency converter is arranged on the electric equipment with larger power, so that the power-saving effect is obvious.

9. The operation is simple, the automatic control degree is high: the system can be started and stopped immediately, and the ignition source is cut off for 30 seconds to enter normal operation; the shutdown can be realized by cutting off the supply of the pulverized coal. The system automatically monitors and adjusts the operation parameters to ensure that the system is in the optimal operation state; meanwhile, the labor intensity and the interference of human factors to the operation of the boiler are reduced.

10. The environment-friendly emission is qualified: the pulverized coal burner adopts a low-nitrogen combustion design, has a uniform temperature field, and avoids a large amount of NOx generated by local high-temperature combustion; flue gas adopts dust collectors of colleges and universities such as a desulfurization device, a bag-type dust collector and the like, the emission concentration of pollutants discharged by the atmosphere is low, and the environmental protection requirement is met; the fly ash is collected into an ash tank and discharged by a closed system, and no secondary pollution is caused.

11. The coal is not burnt, and the surrounding environment of the boiler room is good: the powder is transported to the front of the boiler by the coal powder tank vehicle and stored in the powder bin, so that the whole process runs in a closed manner without leakage, and the environment around the boiler room is greatly improved.

12. Land conservation: the boiler room has no coal yard and slag yard and occupies small area.

The above only is the embodiment of the present invention, not limiting the patent scope of the present invention, all the equivalent structures or equivalent processes that are used in the specification and the attached drawings or directly or indirectly applied to other related technical fields are included in the patent protection scope of the present invention.

Claims

1. The vertical pulverized coal boiler is characterized by comprising a hearth and a vertical shaft flue, wherein the vertical shaft flue is tightly attached to a water-cooled wall of the hearth.

2. The vertical pulverized coal fired boiler according to claim 1, wherein a membrane wall sealing structure is provided at a rear portion of the shaft flue for sealing the shaft flue to prevent air leakage.

3. The vertical pulverized coal fired boiler according to claim 1, further comprising a burner connected to the furnace, the burner being a mixed flow burner comprising a straight flow and a swirling flow.

4. The vertical pulverized coal-fired boiler according to claim 3, characterized in that the mixed-flow burner has a four-stage staged air distribution comprising a three-stage bundled swirl and a one-stage straight jet.

5. The vertical pulverized coal boiler as claimed in claim 4, wherein the number of the burners is two, and the two burners are arranged in opposition.

6. The vertical pulverized coal fired boiler according to claim 1, wherein the furnace is a four-sided membrane type water-cooled wall, the upper part of the furnace is a combustion chamber, and the lower part of the furnace is a cold ash hopper for cooling ash.

7. The vertical pulverized coal fired boiler according to claim 6, wherein a slag outlet and a slag outlet door are provided below the cold ash hopper, and the slag outlet door is connected with a mechanical slag conveyor.

8. The vertical pulverized coal fired boiler according to claim 1, further comprising a slag condensing tube bundle and a steering chamber, wherein the slag condensing tube bundle is connected with the combustion chamber, and the steering chamber is connected with the slag condensing tube bundle.

9. The vertical pulverized coal boiler as claimed in claim 8, wherein the shaft flue comprises a convection bank connected to the turn room.

10. The vertical pulverized coal fired boiler according to claim 9, wherein the shaft flue further comprises an SCR denitration device, and the SCR denitration device is disposed below the shaft flue and connected to the convection bank.