CN212005631U

CN212005631U - Biomass boiler with external fluidized bed

Info

Publication number: CN212005631U
Application number: CN202020140216.9U
Authority: CN
Inventors: 李永华; 徐建东; 刘影; 瞿云富; 高杰
Original assignee: Hangzhou Guozhen Yitaike Engineering Technology Co ltd
Current assignee: Hangzhou Guozhen Yitaike Engineering Technology Co ltd
Priority date: 2020-01-22
Filing date: 2020-01-22
Publication date: 2020-11-24
Anticipated expiration: 2030-01-22

Abstract

The utility model provides a biomass boiler with an external fluidized bed, which comprises a hearth, an air distribution plate, two separators, an external fluidized bed and a tail flue; the bottom of the hearth is provided with an air distribution plate, the rear side of the top of the hearth is provided with two separators, the tops of the separators are connected with a tail flue, a blanking pipe at the lower ends of the separators is connected with the upper end of an external fluidized bed, and the side wall at the lower end of the external fluidized bed is connected with an ash return port at the side wall at the lower part of the hearth; the external fluidized bed is provided with a first hearth, a second hearth and a third hearth in parallel along the width of the hearths, and a first-stage high-temperature superheater, a reheater and a second-stage high-temperature superheater are respectively arranged in the first hearth, the second hearth and the third hearth. Be equipped with external fluidized bed's biomass boiler, fundamentally has avoided current biomass fluidized bed boiler's over heater, re-heater high temperature corrosion problem. The external fluidized bed has the function of adjusting the furnace temperature, can adapt to the larger changes of load and fuel, and simultaneously ensures lower pollutant emission.

Description

Biomass boiler with external fluidized bed

Technical Field

The utility model belongs to the technical field of fluidized bed boiler, especially, relate to a biomass boiler who is equipped with external fluidized bed.

Background

The biomass direct-fired fluidized bed boiler is a high-temperature, ultrahigh-pressure and single-reheat boiler. The biomass boiler furnace entering fuel has large change, corn straws, wheat straws, forestry wastes, building templates and the like are main fuels, the difference of various fuel components, water content and heat value is large, the supply amount of different fuels has large change, and the moisture content of the fuels also has large change; the biomass fuel has high Cl, K and Na contents, and can form ash deposits on the surfaces of tubes of a high-temperature superheater and a high-temperature reheater to generate high-temperature corrosion, which is one of the main reasons for shutdown maintenance of the high-parameter fluidized bed boiler.

The existing biomass fluidized bed boiler mainly comprises the following components: (1) half tower type: the middle part is equipped with the water-cooling screen in the furnace, and upper portion is equipped with high temperature over heater, reheater. The furnace type hearth has low temperature, and the combustion efficiency and the pollutant discharge are not ideal. (2) A four-channel type: the middle lower part of the hearth is provided with a water-cooling screen, the middle upper part is provided with a superheating screen, and the high-temperature superheater and the reheater are arranged in the tail convection flue. The temperature of the hearth is high, and the temperature of the smoke at the outlet of the hearth is high. Superheater and reheater are susceptible to high temperature corrosion. (3) With the structure of the coal-fired boiler, the middle upper part of the hearth is provided with the water cooling and overheating screen, the high-temperature superheater and the low-temperature superheater are arranged on the upper part of the tail flue, the fuel adaptability is poor, and the dust deposition and corrosion conditions are easy to occur on the heated surface of the tail. With the above furnace type, when the load of fuel and boiler changes, the temperature of the hearth is difficult to control, and the adaptability of the boiler load is poor.

SUMMERY OF THE UTILITY MODEL

To the technical problem, an object of the utility model is to provide a biomass boiler who is equipped with external fluidized bed arranges high temperature over heater, reheater in external fluidized bed to avoid high temperature corrosion, boiler combustion efficiency is high, pollutant emission concentration is low, the fault rate is low.

The utility model adopts the technical proposal that:

a biomass boiler with an external fluidized bed comprises a hearth, an air distribution plate, at least one separator, the external fluidized bed and a tail flue; the bottom of the hearth is provided with an air distribution plate, the rear side of the top of the hearth is provided with at least one separator, the top of the separator is connected with a tail flue, a blanking pipe at the lower end of the separator is connected with the upper end of the external fluidized bed, and the side wall at the lower end of the external fluidized bed is connected with an ash return port at the side wall at the lower part of the hearth; the external fluidized bed is characterized in that a first external fluidized bed, a second external fluidized bed and a third external fluidized bed are arranged in parallel along the width of the hearth, a first-stage high-temperature superheater, a reheater and a second-stage high-temperature superheater are respectively arranged in the first external fluidized bed, the second external fluidized bed and the third external fluidized bed, and the adjacent first external fluidized bed, the second external fluidized bed and the third external fluidized bed are separated by a furnace wall.

Be equipped with external fluidized bed's biomass boiler, wherein, one-level high temperature over heater the re-heater with second grade high temperature over heater's heating surface is snakelike tubular arrangement.

Be equipped with biomass boiler of external fluidized bed, wherein, be equipped with first interface channel, second interface channel and third interface channel in the external fluidized bed, first interface channel the second interface channel with third interface channel's one end respectively with external fluidized bed one, external fluidized bed two and external fluidized bed three are connected, the other end respectively with furnace returns the ash mouth and connects.

Be equipped with external fluidized bed's biomass boiler, wherein, afterbody flue include cooling chamber and first vertical flue, the cooling chamber sets up the upper portion of separator, the cooling chamber covers every separator, the upper end of first vertical flue directly with the cooling chamber links to each other.

Be equipped with external fluidized bed's biomass boiler, wherein, the width of cooling chamber with the width at furnace top is the same, constitute by the water-cooling wall around the cooling chamber.

The biomass boiler with the external fluidized bed provided by the utility model is characterized in that the tail flue also comprises a second vertical flue and a third vertical flue, the lower end of the first vertical flue is connected with the lower end of the second vertical flue, the upper end of the second vertical flue is connected with the upper end of the third vertical flue, and the lower end of the third vertical flue is provided with a flue gas outlet; and a plurality of groups of low-temperature superheaters are arranged in the second vertical flue at intervals from top to bottom, and an economizer and an air preheater are arranged in the third vertical flue from top to bottom.

Be equipped with external fluidized bed's biomass boiler, wherein, furnace includes lower part furnace and upper portion furnace, lower part furnace is the diaphragm type wall structure for laying fire-resistant wear-resisting concrete, upper portion furnace is the diaphragm type wall structure.

The biomass boiler with the external fluidized bed of the utility model is characterized in that one section of the lower furnace is trapezoidal, and the other section is rectangular; and the lower hearth is provided with two layers of secondary air, a feeding port and three ash return ports.

Be equipped with external fluidized bed's biomass boiler, wherein, the vertical flue of second with the vertical flue of third is the structure of falling the U-shaped.

Be equipped with external fluidized bed's biomass boiler, wherein, the separator is cyclone.

The utility model discloses beneficial effect:

be equipped with external fluidized bed's biomass boiler, arrange two-stage high temperature over heater and one-level reheater side by side in external fluidized bed, the respective heat absorption capacity of control that can be independent, the temperature of control superheated steam, reheat steam can avoid high temperature corrosion, high temperature corrosion's leading cause is the corruption to the metal under the high temperature of elements such as Cl, Na, K in the flue gas, especially high temperature over heater, reheater take place more easily. The utility model discloses place high temperature over heater, reheater in external fluidized bed, the heating surface pipe does not contact with the flue gas, but carries out the heat transfer with ash (the finer sand of granule) and the fluidizing air that separate in the flue gas. The flue gas entering the separator from the hearth contains a large amount of ash, wherein the very fine ash and the fly ash with low density are discharged from the upper part of the separator along with the flue gas and enter a tail heating surface; the ash (fine sand) with larger particles is separated out and enters the external fluidized bed from the lower part of the separator. At high temperature, Cl, Na, K and other elements form gaseous compounds which flow away along with the flue gas and hardly enter the external fluidized bed, thereby cutting off the substance factors of high-temperature corrosion. The external fluidized bed fundamentally avoids the problem of high-temperature corrosion of a superheater and a reheater of the existing biomass fluidized bed boiler because the contents of components such as K, Na, Cl and S are extremely low. The external fluidized bed has the function of adjusting the furnace temperature, so that the external fluidized bed can adapt to larger changes of load and fuel, and simultaneously ensures lower pollutant emission.

Be equipped with external fluidized bed's biomass boiler, set up the cooling chamber at the separator top to absorb the flue gas heat, the high velocity air who comes out cyclone simultaneously slows down, at the uniform velocity, slows down the wearing and tearing to the afterbody, as the continuation of cooling chamber, first vertical flue is direct to link to each other with the cooling chamber, the flue gas continues the cooling in this first vertical flue, and passes to intraductal working medium with the heat.

Drawings

FIG. 1 is a schematic structural view of a biomass boiler equipped with an external fluidized bed according to the present invention;

FIG. 2 is a front view of the furnace chamber, the air distribution plate and the external fluidized bed according to the present invention;

FIG. 3 is a top view of the furnace, the grid plate and the external fluidized bed according to the present invention;

FIG. 4 is a front view of the centrifuge, cooling chamber and first vertical flue of the present invention;

fig. 5 is a top view of the centrifuge, cooling chamber and first vertical flue of the present invention.

The invention will be further described with reference to specific embodiments and drawings.

Detailed Description

In the description of the present application, it is to be understood that the terms "upper", "lower", "left", "right", "front", "rear", "inner", "outer", and the like, indicate orientations or positional relationships that are used to simplify the description of the present application, based on the orientations or positional relationships shown in the drawings, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered limiting of the present application.

As shown in fig. 1 to 5, a biomass boiler equipped with an external fluidized bed comprises a furnace 1, an air distribution plate 2, two separators 3, an external fluidized bed 4, a cooling chamber 5, a first vertical flue 6, a second vertical flue 7 and a third vertical flue 8, wherein the separator 3 is a cyclone separator.

The hearth 1 comprises a lower hearth 11 and an upper hearth 12, the lower hearth 11 is a film-type wall structure for laying fire-resistant and wear-resistant concrete, and the lower hearth 11 is provided with two layers of secondary air, a feeding port and three ash return ports; one section of the lower furnace 11 is trapezoidal (see fig. 1) and the other section (left view in fig. 1) is rectangular. The upper furnace 12 is a membrane wall structure to absorb the heat of the flue gas.

An air distribution plate 2 is arranged at the bottom of the hearth 1, two separators 3 are arranged on the rear side of the top of the hearth 1, the tops of the separators 3 are connected with a tail flue, a blanking pipe at the lower ends of the separators 3 is connected with the upper end of an external fluidized bed 4, and the side wall of the lower end of the external fluidized bed 4 is connected with an ash return port on the side wall of the lower part of the hearth 1.

The external fluidized bed 4 is divided into three parts along the width of the hearth 1, a first external fluidized bed, a second external fluidized bed and a third external fluidized bed are respectively arranged from left to right in parallel, a first-stage high-temperature superheater 41, a reheater 42 and a second-stage high-temperature superheater 43 are respectively arranged in the first external fluidized bed, the second external fluidized bed and the third external fluidized bed, and the three parts can independently control respective heat absorption capacity and control the temperature of superheated steam and reheated steam. And the adjacent first external fluidized bed, the second external fluidized bed and the third external fluidized bed are separated by a furnace wall 44. The heating surfaces of the primary high-temperature superheater 41, the reheater 42 and the secondary high-temperature superheater 43 are all arranged in a serpentine tube manner. A first connecting channel 45, a second connecting channel 46 and a third connecting channel 47 are arranged in the external fluidized bed 4, one end of the first connecting channel 45, one end of the second connecting channel 46 and one end of the third connecting channel 47 are respectively connected with the first external fluidized bed, the second external fluidized bed and the third external fluidized bed, the other end of the first connecting channel 45, the second external connecting channel 46 and the third external connecting channel 47 are respectively connected with the ash return port of the hearth 1, and the ash return port is arranged on the lower hearth 11 in the middle of the bottom of the external fluidized bed 4.

The tail flue comprises a cooling chamber 5, a first vertical flue 6, a second vertical flue 7 and a third vertical flue 8. A cooling chamber 5 is provided at the upper part of the separators 3, the cooling chamber 5 covers both the separators 3, and the width of the cooling chamber 5 is the same as the width of the ceiling of the furnace 1. The periphery of the cooling chamber 5 is composed of water-cooled walls to absorb the heat of the flue gas, and simultaneously, the high-speed airflow from the separator 3 is decelerated and uniform, and the abrasion to the tail part is slowed down. As the continuation of the cooling chamber 5, the upper end of the first vertical flue 6 is directly connected with the cooling chamber 5, and the flue gas is continuously cooled in the first vertical flue 6 and transfers heat to the working medium in the pipe. The lower extreme of first vertical flue 6 is connected with the lower extreme of second vertical flue 7, and the upper end of second vertical flue 7 is connected with the upper end of third vertical flue 8, and the lower extreme of third vertical flue 8 is equipped with the exhanst gas outlet, and 5 groups low temperature superheater have been arranged to the inside from top to bottom interval of second vertical flue 7, and economizer and air heater have been arranged to the inside from top to bottom of third vertical flue 8, and the flue gas is followed after cooling to 130 ℃ the exhanst gas outlet discharges, and second vertical flue 7 and third vertical flue 8 are the structure of falling the U-shaped.

The working process of the biomass boiler with the external fluidized bed in the embodiment is as follows:

the fuel is fed into the lower hearth 11, the air distribution plate 2 uses primary air to fluidize the bed material to form a dense phase combustion zone, and the fuel and the high-temperature bed material in the furnace start to combust after being mixed. The flue gas and the fly ash are led out from the top of the separator 3 and enter a tail flue; after entering the external fluidized bed 4 from the bottom of the separator 3, the high-temperature fine sand is fluidized by fresh air, exchanges heat with the primary high-temperature superheater 41, the reheater 42 and the secondary high-temperature superheater 43, and after the temperature is reduced to about 600 ℃, cooled ash returns to the furnace 1 through the first connecting channel 45, the second connecting channel 46 and the third connecting channel 47, and transfers heat to steam.

The utility model discloses not arranging screen formula heating surface in furnace 1, arranging two-stage high temperature over heater and one-level re-heater heating surface in external fluidized bed 4, this external fluidized bed 4 has avoided wearing and tearing, the high temperature corrosion of screen formula heating surface in furnace 4, has simplified the furnace structure, is favorable to organizing the burning in the stove, and furnace 1's combustion temperature control does benefit to in-furnace desulfurization, denitration, reduces the original pollutant emission of boiler at 850 ℃.

The above-mentioned embodiments are only for describing the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention, and various modifications and improvements made by those skilled in the art without departing from the design spirit of the present invention should fall into the protection scope defined by the claims of the present invention.

Claims

1. The utility model provides a be equipped with external fluidized bed's biomass boiler which characterized in that: comprises a hearth (1), an air distribution plate (2), at least one separator (3), an external fluidized bed (4) and a tail flue; the bottom of the hearth (1) is provided with an air distribution plate (2), the rear side of the top of the hearth (1) is provided with at least one separator (3), the top of the separator (3) is connected with a tail flue, a blanking pipe at the lower end of the separator (3) is connected with the upper end of the external fluidized bed (4), and the side wall at the lower end of the external fluidized bed (4) is connected with an ash return port at the side wall at the lower part of the hearth (1); the external fluidized bed (4) is arranged with an external fluidized bed I, an external fluidized bed II and an external fluidized bed III in parallel along the width of the hearth (1), a first-stage high-temperature superheater (41), a reheater (42) and a second-stage high-temperature superheater (43) are respectively arranged in the external fluidized bed I, the external fluidized bed II and the external fluidized bed III, and the adjacent external fluidized bed I, the external fluidized bed II and the external fluidized bed III are separated by a furnace wall (44).

2. The external fluidized bed-equipped biomass boiler according to claim 1, characterized in that: heating surfaces of the primary high-temperature superheater (41), the reheater (42) and the secondary high-temperature superheater (43) are all arranged in a coiled pipe manner.

3. The external fluidized bed-equipped biomass boiler according to claim 1, characterized in that: be equipped with first interface channel (45), second interface channel (46) and third interface channel (47) in external fluidized bed (4), first interface channel (45), second interface channel (46) and the one end of third interface channel (47) respectively with external fluidized bed one, external fluidized bed two and external fluidized bed three are connected, and the other end respectively with the return ash mouth of furnace (1) is connected.

4. The external fluidized bed-equipped biomass boiler according to claim 1, characterized in that: the tail flue comprises a cooling chamber (5) and a first vertical flue (6), the cooling chamber (5) is arranged on the upper portion of the separator (3), the cooling chamber (5) covers each separator (3), and the upper end of the first vertical flue (6) is directly connected with the cooling chamber (5).

5. The external fluidized bed-equipped biomass boiler according to claim 4, characterized in that: the width of the cooling chamber (5) is the same as that of the top of the hearth (1), and the periphery of the cooling chamber (5) is composed of water-cooled walls.

6. The external fluidized bed-equipped biomass boiler according to claim 4, characterized in that: the tail flue also comprises a second vertical flue (7) and a third vertical flue (8), the lower end of the first vertical flue (6) is connected with the lower end of the second vertical flue (7), the upper end of the second vertical flue (7) is connected with the upper end of the third vertical flue (8), and the lower end of the third vertical flue (8) is provided with a flue gas outlet; a plurality of groups of low-temperature superheaters are arranged in the second vertical flue (7) at intervals from top to bottom, and an economizer and an air preheater are arranged in the third vertical flue (8) from top to bottom.

7. The external fluidized bed-equipped biomass boiler according to claim 1, characterized in that: the hearth (1) comprises a lower hearth (11) and an upper hearth (12), the lower hearth (11) is a film-type wall structure for laying fire-resistant and wear-resistant concrete, and the upper hearth (12) is a film-type wall structure.

8. The external fluidized bed-equipped biomass boiler according to claim 7, characterized in that: one section of the lower hearth (11) is trapezoidal, and the other section of the lower hearth is rectangular; and the lower hearth (11) is provided with two layers of secondary air, a feeding port and three ash return ports.

9. The external fluidized bed-equipped biomass boiler according to claim 6, characterized in that: the second vertical flue (7) and the third vertical flue (8) are of inverted U-shaped structures.

10. The biomass boiler equipped with an external fluidized bed according to any one of claims 1 to 9, wherein: the separator (3) is a cyclone separator.