CN108916861B

CN108916861B - Biomass powder controllable turbulence premixed combustion boiler and application method thereof

Info

Publication number: CN108916861B
Application number: CN201811062950.1A
Authority: CN
Inventors: 段景峰
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-09-12
Filing date: 2018-09-12
Publication date: 2023-09-15
Anticipated expiration: 2038-09-12
Also published as: CN108916861A

Abstract

The invention provides a biomass powder controllable turbulence premixed combustion boiler and a using method thereof. The biomass powder controllable turbulent premixed combustion boiler and the use method thereof solve the problems that in the prior art, flames cannot be directionally and orderly controlled, combustion ashes are accumulated in dead angles, biomass powder is incompletely combusted, and a high-power induced draft fan is arranged for wind direction traction.

Description

Biomass powder controllable turbulence premixed combustion boiler and application method thereof

Technical Field

The invention relates to a biomass powder controllable turbulence premixed combustion boiler and a combustion method thereof, and belongs to the technical field of biomass powder fuel boilers.

Background

Traditional biomass powder burns and adopts direct spray-fire boiler or the direct spray-fire boiler of buggy, and the combustion chamber adopts hexahedral structure, flame and flue gas outlet design top have a plurality of dead angles in the combustion chamber, cause the ash content to pile up at the air current dead angle, because the unordered uncontrollable burning position of turbulent premixed combustion flame state in the combustion chamber, the suitable feeding position can't be found to the overgrate air, and partial fuel that does not burn completely is carried by the flue gas and escapes, leads to biomass powder to burn incompletely. The boiler adopting the smoke turning-back technology of the independent jet head has the advantages that flame weakens at a first turning-back point due to huge resistance, heat generated by the flame is absorbed by the boiler wall, a part of heat is wasted, the flame cannot burn completely due to repeated turning-back and cooling, secondary air and tertiary air are not provided with reasonable space, incomplete combustion is finally caused, a large amount of black carbon-containing particles are in the smoke, and recycling and environmental pollution are not facilitated. Meanwhile, as the heat exchange mode of the traditional boiler is that the flue gas passes through the tube side of the heat exchanger, besides the defect that the resistance is large and the induced draft fan is necessary to be used for forced smoke exhaust, dust in the flue gas can block the pipeline to ensure that the flue gas cannot be smoothly exhausted. In addition, the traditional technology in the field has many defects in the aspects of realizing automatic control, automatic ash removal, combustion power design trial range and the like.

Disclosure of Invention

The invention aims to solve the problems that in the biomass powder fuel device in the prior art, flames are in a disordered uncontrollable state and cannot be controlled in an oriented and ordered manner due to the shape limitation of a combustion space, so that combustion ashes are accumulated in dead corners, and matched machinery is required to clean the ashes; the secondary air can not find a proper feeding position, partial fuel which is not completely combusted is carried by flue gas to escape, so that biomass powder is incompletely combusted, and meanwhile, a high-power induced draft fan is required to be equipped for wind direction traction.

The invention adopts the following technical scheme to achieve the aim:

the biomass powder controllable turbulent premixed combustion boiler comprises an injection port, a tertiary air supply pipe, a flue gas outlet, a tubular heat exchange pipe, a secondary air supply pipe, a main combustion chamber, a main duty flame chamber and a secondary duty flame chamber; the main combustion chamber is formed by integrally forming a cylindrical sleeve-shaped side wall and a top plate, the auxiliary flame chamber is located inside the main combustion chamber and connected with the top plate, the jet orifice penetrates through the top plate and stretches into the auxiliary flame chamber, the main flame chamber is arranged at an air outlet of the auxiliary flame chamber, the main flame chamber comprises a blunt body, a fire leading hole and a flame jet hole, the side wall of the air outlet of the main flame chamber is provided with the flame jet hole, the blunt body is correspondingly arranged at the air inlet of the main flame chamber opposite to the jet orifice, the fire leading hole is arranged on the side wall of the main flame chamber, the secondary air supply pipe stretches into the main combustion chamber from the top plate and surrounds the periphery of the main flame chamber, the tertiary air supply pipe stretches into the main combustion chamber from the top plate and is located below the main combustion chamber and is used for blowing ash completely combusted out of the main combustion chamber, the tubular heat exchange pipe is arranged behind the air outlet of the main flame chamber, and the flue gas outlet is arranged at the air outlet of the main combustion chamber.

Preferably, the blunt body is in the shape of a cone.

Preferably, the hemispherical shape, and a surface opposite to the ejection port is a hemispherical spherical shape.

Preferably, the tertiary air supply pipe is provided with two rows of directional air flows which are used for supporting combustion and blowing ash which is completely combusted out of the main combustion chamber.

Preferably, two openings are arranged above and below the flue gas outlet for actively discharging flue gas.

Preferably, the tube heat exchange tube adopts a mode that tube side fluid is micro-positive pressure water.

Preferably, the side wall of the main combustion chamber comprises an inner housing and an outer housing, the inner housing and the outer housing form a sleeve structure, and cooling water is filled between the inner housing and the outer housing.

Preferably, the flue gas outlet is of a wide mouth design.

A method of using the biomass powder controlled turbulence premix combustion boiler, comprising the steps of:

step one: firstly, uniformly mixing air and biomass powder fuel in advance to form a mixture, injecting the mixture into a secondary flame chamber through an injection port, guiding the mixture to change the movement direction under the dispersion and blocking actions of a blunt body, refracting a part of the mixture into a main flame chamber in a casting state, forming a main backflow area in the main flame chamber, reflecting one part of wind to the side wall of the secondary flame chamber through the blunt body, forming a secondary backflow area in the secondary flame chamber, and dispersing the other part of wind to the periphery of the main flame chamber;

step two: the pilot flame is ejected from the pilot hole to ignite the mixture in the main duty flame chamber, part of biomass powder with smaller particle size in the mixture in the main duty flame chamber and the auxiliary duty flame chamber is directly combusted, part of biomass powder with larger particle size begins to combust on the surface, the released heat heats the side walls of the main duty flame chamber and the auxiliary duty flame chamber and rapidly increases the temperature of the inner wall to more than 1000 ℃, at this moment, the main duty flame chamber forms controllable turbulence premixed combustion flame, the rest of biomass powder with larger particle size is heated and volatilized out of inflammable gas, the inflammable gas escapes from the main duty flame chamber and the auxiliary duty flame chamber and enters the controllable turbulence premixed combustion flame, the mixture outside the main duty flame chamber is blown to the controllable turbulence premixed combustion flame through the wind feeding action of a secondary wind pipe, and most of fuel forms a layer of turbulent flame outside the controllable turbulence premixed combustion flame and fully combusts due to the larger space of the main combustion chamber;

step three: the biomass powder with large particle size and incomplete combustion falls on the bottom of the main combustion chamber, directional air flow given by the tertiary air supply pipe is used for supporting combustion and plays a role in supporting continuous combustion of controllable turbulent premixed combustion flame;

step four: the controllable turbulent premixed combustion flame and the flue gas enter a shell side formed by the tubular heat exchange tube and the inner shell of the main combustion chamber and move towards the direction of the flue gas outlet, and the temperature of the water in the tubular heat exchange tube side is increased due to the high temperature effect of the controllable turbulent premixed combustion flame and the flue gas.

The working principle of the biomass powder controllable turbulence premixed combustion boiler provided by the invention is as follows:

after being sprayed to a blunt plate with a certain angle with a horizontal plane and a certain size, which is arranged at an inlet of a main valve flame chamber, a cylindrical biomass powder fuel and air mixture sprayed out of a spray orifice is sprayed to the blunt plate, the biomass powder and air mixture suspension flow is guided to change the movement direction, the mixture is projected into the main valve flame chamber and is reflected to the side wall of the auxiliary valve flame chamber, two spaces which are formed in the front and back surfaces of the blunt plate, the main valve flame chamber and the auxiliary valve flame chamber, the relative flow velocity of the mixture of two materials and air is small and can form backflow are formed in the blunt plate, a pilot hole is designed in the space, under the action of pilot flame, the fuel powder is ignited in the valve flame chamber, part of the smaller particle size powder is directly combusted, part of the larger particle size powder begins to be combusted, the released heat heats the side wall of the main valve flame chamber and the auxiliary valve flame chamber and quickly enables the temperature of the side wall to rise to be more than 1000 ℃, the rest fuel powder is heated and volatilized from the main valve flame chamber and the auxiliary valve flame chamber, a controllable turbulent premixed combustion is formed, the secondary turbulent combustion is enabled to escape to pass through the escape outlet, the premixed combustion is enabled to continuously support the turbulent combustion of the liquid flame in the main valve flame chamber, the turbulent combustion is enabled to be enabled to continuously in the main air duct or the turbulent combustion chamber, the turbulent combustion is enabled to continuously enabled to be enabled to have a large turbulent combustion effect, and the turbulent combustion flame is enabled to continuously to be enabled to be in the main combustion flame combustion is enabled to be in the main combustion air duct or the main combustion duct is enabled to continuously to have a large turbulent combustion condition, and the turbulent combustion is enabled to continuously is enabled to have a large combustion effect and has a turbulent combustion effect and has a flame combustion effect flame combustion effect is enabled.

The biomass powder controllable turbulence premixed combustion boiler has the beneficial effects that:

(1) The invention is based on the traditional injection technology of powder combustion, a blunt body, a main valve flame chamber and a secondary valve flame chamber are added, the movement state of the powder after injection is changed, the flow velocity of the mixture of air and biomass powder fuel in the main valve flame chamber is greatly reduced, and a backflow area is generated after the blunt body, so that the injected powder fuel and air mixture form a turbulent premixed flame state similar to natural gas combustion, the controllable turbulent premixed flame is ensured to move directionally, the unordered state of the original flame is overcome, and the combustion process is controllable.

(2) According to the invention, the secondary air supply pipe is arranged outside the main shift, and laminar flame is formed at the rear end of turbulent premixed flame, so that powder can be fully combusted.

(3) The main combustion chamber is designed into a sleeve shape and is horizontally arranged, and the diameter and the length of the inner cylinder of the sleeve are changed to adapt to different combustion strengths so as to form boilers with different specifications and heat production strengths. The main combustion chamber is designed into a sealed sleeve structure, water flow is formed in the sleeve, and the sleeve replaces refractory bricks, so that the weight of the boiler is reduced, and meanwhile, the heat exchange efficiency is improved. The main combustion chamber is designed into a sealed cylinder shape except the flue gas outlet, so that the heat efficiency is improved, other cylinders can be square cylinders, the material can be common refractory bricks and refractory cement concrete, and the main combustion chamber provides a combustion space for the turbulent premixed combustion flame of the controllable biomass powder.

(4) Compared with the closing-in design of the outlet of the traditional boiler, the main combustion chamber adopts a wide-mouth design, and the smoke outlet of the main combustion chamber can be directly connected with a chimney, so that the smoke is automatically discharged to the atmosphere by utilizing the lifting force generated by the temperature of the smoke, and the induced draft fan is removed.

(5) The tubular heat exchanger is arranged at the rear part of the boiler cavity controllable turbulence premixed combustion flame, so that the high-temperature flame and the flue gas exchange heat with flowing normal-pressure water, and the heat exchanger shell pass is directly formed by the boiler cavity and the heat exchanger, so that the defect that the flue gas of the traditional powder jet combustion boiler is blocked by the tube pass is avoided.

(6) The directional air flow given by the tertiary air supply double-row pipe is used for jetting air flow to the inner side at a certain speed for tertiary air supply, so that larger particles falling on the bottom of the boiler continue to burn until the combustion is complete, and ash is blown out of the main combustion chamber. The method and the device for realizing the method realize the function of automatic ash removal, and avoid the defect that the traditional powder burning boiler needs to stop the furnace for ash removal or adds a complex ash removal system.

(7) The invention forms stable controllable turbulent premixed combustion integral flame through the duty flame chamber, ensures the directional ordered control of the flame, and simultaneously ensures the full combustion of biomass powder.

(8) The flame in the main combustion chamber is controllable turbulent premixed flame, is directional flame injection, provides an advantageous foundation for the design of a boiler body, can be designed into a cylinder shape, can be provided with a directional air pipe for blowing air at the lower part of the boiler body, ensures that ash is blown out of the boiler body in a directional motion, and omits a mechanical ash removing device.

Drawings

FIG. 1 is a schematic diagram of a biomass powder controlled turbulence premix combustion boiler according to the present invention;

FIG. 2 is a schematic partial perspective view of a biomass powder controlled turbulence premix combustion boiler according to the present invention;

wherein the arrow indicates the flow direction of the biomass powder and air mixture;

in the figure: 1-jet ports; 2-blunt body; 3-tertiary air supply pipe; 4-a flue gas outlet; 5-tube heat exchange tubes; 6-secondary air supply pipe; 7-a main combustion chamber; 8-an outer shell; 9-an inner housing; 10-a main shift flame chamber; 11-a secondary flame room; 12-controllable turbulent premix flame; 13-a main reflux zone; 14-a secondary reflux zone; 15-a fire hole; 16-flame injection holes.

Detailed Description

The technical scheme of the invention is further described below by the specific embodiments with reference to the accompanying drawings.

The first embodiment is described with reference to fig. 1-2, and the biomass powder controllable turbulent premixed combustion boiler according to the present embodiment includes an injection port 1, a tertiary air supply pipe 3, a flue gas outlet 4, a tubular heat exchange pipe 5, a secondary air supply pipe 6, a main combustion chamber 7, a main shift flame chamber 10 and a secondary shift flame chamber 11; the main combustion chamber 7 is formed by integrally forming a cylindrical sleeve-shaped side wall and a top plate, the auxiliary flame chamber 11 is located inside the main combustion chamber 7 and connected with the top plate, the jet orifice 1 penetrates through the top plate and stretches into the auxiliary flame chamber 11, the main flame chamber 10 is installed at an air outlet of the auxiliary flame chamber 11, the main flame chamber 10 comprises a blunt body 2, a pilot hole 15 and a flame jet hole 16, the side wall of the air outlet of the main flame chamber 10 is provided with the flame jet hole 16, the blunt body 2 is correspondingly arranged at an air inlet of the main flame chamber 10 opposite to the jet orifice 1, the pilot hole 15 is installed on the side wall of the main flame chamber 10, the secondary air supply pipe 6 stretches into the main combustion chamber 7 from the top plate and surrounds the periphery of the main flame chamber 10, the tertiary air supply pipe 3 stretches into the main combustion chamber 7 from the top plate and is located below the main combustion chamber 7 and is used for blowing ash completely combusted into the main combustion chamber 7, the main heat pipe 5 is installed at the air outlet of the main combustion chamber 7, and the flue gas is installed at the air outlet 4 of the main combustion chamber.

The blunt body 2 is in the shape of a cone or the blunt body 2 is in the shape of a hemispherical surface, and a surface facing the injection port 1 is in the shape of a hemispherical surface.

The mixture of air and biomass powder fuel is guided to change the movement direction through the dispersion and the blocking effect of the blunt body 2 in the duty flame chamber 10, one part of the mixture is scattered into a projection state uniformly in the main duty flame chamber 10, a main backflow area 13 is formed in the inner side area of the blunt body 2 in the main duty flame chamber 10, the other part of the mixture is reflected by the blunt body 2, backflow is formed in the auxiliary backflow area 14 in the auxiliary duty flame chamber 11, finer fuel particles are directly combusted in the duty flame chamber 10 and the auxiliary duty flame chamber 11, a part of particle fuel with larger particle size in the main duty flame chamber 10 and the auxiliary duty flame chamber 11 is initially combusted on the surface layer, and the combustible gas is decomposed and volatilized by the fuel due to the high temperature effect of the duty flame chamber and enters the controllable biomass powder turbulent premixed combustion flame 12.

Only through the blocking and the throwing even scattering functions of the blunt body 2, the mixed airflow of the biomass powder and the air sprayed at high speed can be uniformly and orderly sprayed to the inner walls of the main duty flame chamber 10 and the auxiliary duty flame chamber 11 only when the blunt body 2 is positioned at the inlet of the main duty flame chamber 10, and a main backflow area 13 is generated at the back of the blunt body 2 and an auxiliary backflow area 13 is generated at the front of the blunt body 2, so that the flow velocity of the biomass powder and the air mixture is rapidly reduced, a supporting part of stable controllable biomass turbulent premixed combustion flame is formed, the continuous combustion of the controllable turbulent premixed combustion flame 12 is facilitated, and the controllable turbulent premixed combustion flame 12 has the characteristic similar to the direct combustion of gas, so that the stable controllable turbulent premixed combustion flame 12 with directional movement can be formed only through the combined action of the blunt body 2, the main duty flame 10 and the auxiliary duty flame 11. Only the formation of a stable, directionally moving turbulent premixed flame 12 of biomass powder ensures accurate determination of the exact position of the secondary and tertiary wind feeds.

The tertiary air supply pipe 3 is provided with two rows of directional air flows which are used for supporting combustion and blowing ashes which are completely combusted out of the main combustion chamber 7.

The directional air flow given by the tertiary air supply double-row pipe 3 has the combustion supporting function, and more important functions are that ash which is completely burnt is blown out of the main combustion chamber 7, the direction of the blown air flow is forwards and inwards, and the air outlet holes with a certain distance ensure that the ash is continuously blown in the direction of the smoke outlet, and then the ash is blown out of the main combustion body of the boiler. The method and the device for realizing the method realize the function of automatic ash removal, and avoid the defect that the traditional powder burning boiler needs to stop the furnace for ash removal or adds a complex ash removal system. The secondary air supply pipe 6 supplies air to enable the combustion to be more complete, larger particle size powder is not completely combusted, the powder falls on the bottom of the main combustion chamber, and the directional air flow given by the tertiary air supply double calandria 3 is used for supporting combustion and continues to combust.

The upper and lower openings of the flue gas outlet 4 are used for actively discharging flue gas, so that the effect of canceling the induced draft fan is achieved.

The tube heat exchange tube 5 adopts a mode that tube side fluid is micro-positive pressure water.

The rear part of the main combustion chamber 7 is provided with the tubular heat exchange tube 5, so that high-temperature flame and smoke are subjected to heat exchange with flowing normal-pressure water, and the heat exchanger shell pass is directly formed by the inner cavity of the boiler and the heat exchanger, so that the defect that the smoke of the heat exchanger of the traditional powder jet combustion boiler is blocked by the tube pass is avoided, and the medium of the traditional boiler is exchanged, so that the heat exchanger is free of maintenance.

The side wall of the main combustion chamber 7 comprises an inner shell 9 and an outer shell 8, the inner shell 9 and the outer shell 8 form a sleeve structure, and cooling water is filled between the inner shell 9 and the outer shell 8.

The main combustion chamber 7 is of a sleeve-shaped structure, cooling water is filled in a sleeve interlayer formed by the inner shell 9 and the outer shell 8 to play a role in absorbing heat and reducing temperature, the inner shell 9 is easy to process and has high compressive strength, and is of a rigid structure formed by metal or refractory bricks and refractory concrete, and the function of the main combustion chamber is to provide a space capable of fully burning for biomass powder turbulent premixed flame 12 and to connect and fix various necessary matching devices. The main combustion chamber 7 adopts a wide-mouth design, is favorable for resistance-free smoke discharge of the smoke outlet 4, and does not need to add an additional induced draft fan. The main combustion chamber 7 is designed into a sleeve shape and is horizontally arranged, and the diameter and the length of the inner cylinder of the sleeve are changed to adapt to different combustion strengths so as to form boilers with different heat production strengths.

The flue gas outlet 4 adopts a wide-mouth design.

The main combustion chamber 7 is improved to be a wide-mouth design relative to the mouth-closing design of the outlet of the traditional boiler, and as the smoke outlet 4 of the main combustion chamber 7 can be directly connected with a chimney, the lifting force generated by the temperature of smoke is utilized, the smoke is automatically discharged to the atmosphere, and the induced draft fan is removed.

step one: firstly, air and biomass powder fuel are uniformly mixed in advance to form a mixture, the mixture is sprayed into a secondary duty flame chamber 11 through a spraying port 1, the mixture is guided to change the movement direction under the dispersion and blocking actions of a blunt body 2, one part of the mixture is projected into a main duty flame chamber 10 in a projection state, a main backflow area 13 is formed in the main duty flame chamber 10, one part of air is reflected to the side wall of the secondary duty flame chamber 11 through the blunt body 2, a secondary backflow area is formed in the secondary duty flame chamber 11, and the other part of air is dispersed to the periphery of the main duty flame chamber 10;

step two: the ignition holes 15 spray ignition flames to ignite the mixture in the main duty flame chamber 10, part of biomass powder with smaller particle size in the mixture in the main duty flame chamber 10 and the auxiliary duty flame chamber 11 is directly combusted, part of biomass powder with larger particle size begins to combust, the released heat heats the side walls of the main duty flame chamber 10 and the auxiliary duty flame chamber 11 and rapidly makes the temperature of the inner wall of the main duty flame chamber 10 rise to more than 1000 ℃, at this time, the main duty flame chamber 10 forms a controllable turbulence premixed combustion flame 12, the rest of biomass powder with larger particle size is heated and volatilized flammable gas, the flammable gas escapes from the main duty flame chamber 10 and the auxiliary duty flame chamber 11 and enters the controllable turbulence premixed combustion flame 12, and the mixture outside the main duty flame chamber 10 is blown to the controllable turbulence premixed combustion flame 12 through the wind feeding action of the secondary wind feeding pipe 6;

step three: the biomass powder with large particle size and incomplete combustion falls on the bottom of the main combustion chamber 7, is combured by directional airflow given by the tertiary air supply pipe 3, and plays a role in supporting continuous combustion of the controllable turbulent premixed combustion flame 12;

step four: the controllable turbulent premixed combustion flame 12 and the flue gas enter a shell side formed by the tubular heat exchange tube 5 and the inner shell 9 of the main combustion chamber 7 and move towards the direction of the flue gas outlet 4, and the temperature of the water in the tube side of the tubular heat exchange tube 5 is increased due to the high temperature effect of the controllable turbulent premixed combustion flame 12 and the flue gas.

Although the invention has been described with reference to specific details and examples, it is not intended to be limiting, but rather to modify the parameters appropriately for the skilled person without departing from the true scope of the invention, which is therefore defined by the claims.

Claims

1. The biomass powder controllable turbulence premixed combustion boiler is characterized by comprising an injection port (1), a tertiary air supply pipe (3), a flue gas outlet (4), a tubular heat exchange pipe (5), a secondary air supply pipe (6), a main combustion chamber (7), a main duty flame chamber (10) and a secondary duty flame chamber (11); the main combustion chamber (7) is formed by integrally forming a cylindrical sleeve-shaped side wall and a top plate, the auxiliary duty flame chamber (11) is positioned inside the main combustion chamber (7) and is connected with the top plate, the injection port (1) penetrates through the top plate and stretches into the auxiliary duty flame chamber (11), the main duty flame chamber (10) is arranged at an air outlet of the auxiliary duty flame chamber (11), the main duty flame chamber (10) comprises a blunt body (2), a pilot hole (15) and a flame injection hole (16), the side wall of the air outlet of the main duty flame chamber (10) is provided with a flame injection hole (16), a blunt body (2) is correspondingly arranged at an air inlet of the main duty flame chamber (10) opposite to the injection port (1), a pilot hole (15) is arranged on the side wall of the main duty flame chamber (10), a secondary air supply pipe (6) stretches into the main combustion chamber (7) from the top plate and surrounds the periphery of the main duty flame chamber (10) to provide sufficient oxygen, the main air supply pipe (3) stretches into the main combustion chamber (7) from the top plate and is arranged at the air outlet of the main combustion chamber (7) and is arranged at the air outlet (7) of the main combustion chamber (7), and the main combustion chamber (7) is completely arranged at the top plate (5) after the main combustion chamber (7) is completely burns;

the tertiary air supply pipe (3) is provided with two rows of directional air flows which are used for supporting combustion and blowing ashes completely combusted out of the main combustion chamber (7);

the blunt body (2) is in the shape of a cone.

2. A biomass powder controlled turbulent premix combustion boiler according to claim 1, characterized in that the blunt body (2) is hemispherical in shape and the surface opposite to the injection port (1) is hemispherical in shape.

3. A biomass powder controlled turbulent premix combustion boiler according to claim 1, characterized in that the flue gas outlet (4) is provided with two openings up and down for active flue gas discharge.

4. A biomass powder controllable turbulent premix combustion boiler according to claim 1, wherein the tube heat exchange tube (5) adopts a mode that tube side fluid is micro-positive pressure water.

5. A biomass powder controllable turbulent premix combustion boiler according to claim 1, characterized in that the side wall of the main combustion chamber (7) comprises an inner housing (9) and an outer housing (8), the inner housing (9) and the outer housing (8) form a sleeve structure, and cooling water is filled between the inner housing (9) and the outer housing (8).

6. A biomass powder controlled turbulent premix combustion boiler according to claim 1, characterized in that the flue gas outlet (4) is of a wide mouth design.

7. A method of using a biomass powder controlled turbulent premix combustion boiler as set forth in any one of claims 1-6, comprising the steps of:

step one: firstly, air and biomass powder fuel are mixed uniformly in advance to form a mixture, the mixture is sprayed into a secondary flame chamber (11) through a spraying port (1), the mixture is guided to change the movement direction under the dispersion and blocking actions of a blunt body (2), one part of the mixture is projected into a main flame chamber (10) in a projection state, a main backflow area (13) is formed in the main flame chamber (10), one part of air is reflected to the side wall of the secondary flame chamber (11) through the blunt body (2) and forms a secondary backflow area in the secondary flame chamber (11), and the other part of air is dispersed to the periphery of the main flame chamber (10);

step two: the ignition hole (15) sprays ignition flame to ignite the mixture in the main duty flame chamber (10), part of biomass powder with smaller particle size in the mixture in the main duty flame chamber (10) and the auxiliary duty flame chamber (11) is directly combusted, part of biomass powder with larger particle size begins to combust, the released heat heats the side wall of the main duty flame chamber (10) and the auxiliary duty flame chamber (11) and rapidly makes the temperature of the inner wall rise to more than 1000 ℃, at this moment, the main duty flame chamber (10) forms controllable turbulent premixed combustion flame (12), the rest of biomass powder with larger particle size is heated and volatilized to form inflammable gas, the inflammable gas escapes from the main duty flame chamber (10) and the auxiliary duty flame chamber (11) and enters the controllable turbulent premixed combustion flame (12), the mixture outside the main duty flame chamber (10) is blown to the controllable turbulent premixed combustion flame (12) through the wind feeding effect of the secondary wind supply pipe (6), and most of fuel forms a layer outside the controllable turbulent premixed combustion flame (12) due to the larger space of the main combustion chamber (7);

step three: the biomass powder with large particle size and incomplete combustion falls on the bottom of the main combustion chamber (7), is combured by directional airflow given by the tertiary air supply pipe (3), and plays a role in supporting continuous combustion of controllable turbulent premixed combustion flame (12);

step four: the controllable turbulent premixed combustion flame (12) and the flue gas enter a shell side formed by the tubular heat exchange tube (5) and the inner shell (9) of the main combustion chamber (7), and move in the direction of the flue gas outlet (4), and the temperature of the water in the tube side of the tubular heat exchange tube (5) is increased due to the high temperature effect of the controllable turbulent premixed combustion flame (12) and the flue gas.