A straw-burning boiler with an independent air distribution system

Abstract

The present invention discloses a straw bale burning boiler with an independent air distribution system, comprising a first combustion chamber, a second combustion chamber, a third combustion chamber and an air distribution unit. The air volume delivered by the air distribution unit to the first combustion chamber, the second combustion chamber and the third combustion chamber can be adjusted. During operation, the baled straw is placed in the first combustion chamber, and the air distribution unit delivers air to the first combustion chamber to ensure uniform combustion of the straw bale. During the combustion process, the baled straw fuel sequentially undergoes stages such as water evaporation, precipitation of volatiles and coke formation; the coke produced by the combustion falls into the second combustion chamber through a grate and undergoes secondary air distribution combustion, and the incompletely burned volatiles enter the third combustion chamber through a connecting port along with the flue gas, and the air distribution unit delivers air to the third combustion chamber to burn the volatiles in the flue gas again. The heat generated during the combustion of the straw bale is transferred to a circulating medium through heat exchange for use by a user.

Description

Technical Field

[0001] The invention relates to the technical field of new fuels and peripheral supporting facilities thereof, and in particular to a straw bale burning boiler with an independent air distribution system. Background Art

[0002] Straw bale burning is a better way to utilize straw energy. It is a technical process that picks up and baled the loose straw in the field and then burns it for heating. Baling the straw increases the energy density and reduces the cost of storage and transportation. At the same time, the semi-gasification combustion of the bundled straw greatly improves the combustion efficiency and boiler heating efficiency, which has good economic benefits. At present, there are two main straw bale burning technologies. One is the intermittent feeding straw bale boiler combustion system, which is a method of re-feeding and burning after all the straw fuel in the combustion chamber is burned. The characteristics of intermittent feeding bale burning are small footprint, simple and convenient operation, and can be directly loaded and cleaned manually. It is usually used for heating and heating of small buildings; the other is a continuous bale burning boiler system, which can realize continuous feeding and continuous cleaning during the combustion process, maintain a stable combustion state in the combustion chamber, and the furnace temperature fluctuation is small, which is conducive to intelligent operation and suitable for large buildings or centralized heating areas.

[0003] Countries with relatively mature biomass straw baling and burning technology include Denmark, France and Belgium. Denmark started burning whole bales of straw in the 1970s. The continuous burning equipment developed by Denmark is called Cigar burner. Because its burning method is very similar to that of a lit cigar, it is called Cigar burner. The continuous burning process is well controllable, the furnace temperature is stable, and it is conducive to intelligent operation. Therefore, it has been widely promoted and applied abroad and is considered to be the best way to burn whole bales of straw.

[0004] The research on baling combustion technology in my country started late, there is little research on baling combustion equipment, and the theory of baling combustion needs to be improved. Domestic scholars have studied the combustion characteristics, furnace design and smoke reduction of straw bale burning, and have made great progress. There are also large-scale baling direct combustion projects in northern my country, but in actual operation, there are still problems such as incomplete combustion, low combustion efficiency, excessive nitrogen oxide emissions, and complicated flue gas purification processes.

[0005] Therefore, how to optimize the straw bale burning process, improve the straw bale burning efficiency, and reduce smoke emissions has become a problem that needs to be solved urgently by technical personnel in this field. Summary of the invention

[0006] The purpose of the present invention is to provide a straw bale burning boiler with an independent air distribution system to solve the problems existing in the above-mentioned prior art, improve the combustion efficiency of straw bale burning, avoid thermal stress concentration during combustion, and reduce nitrogen oxide emissions.

[0007] To achieve the above-mentioned purpose, the present invention provides the following scheme: The present invention provides a straw bale burning boiler with an independent air distribution system, comprising a first combustion chamber, a second combustion chamber, a third combustion chamber and an air distribution unit, the second combustion chamber is located at the bottom of the first combustion chamber, the third combustion chamber is connected to the first combustion chamber, the second combustion chamber and the third combustion chamber are respectively connected to the first combustion chamber, a grate is arranged between the first combustion chamber and the second combustion chamber, the grate can place straw bales, a connecting port is arranged between the first combustion chamber and the third combustion chamber, the third combustion chamber is also provided with a smoke exhaust port, the first combustion chamber, the second combustion chamber and the third combustion chamber are all provided with temperature sensors; the air distribution unit is connected to the bottom of the first combustion chamber, the air distribution unit is connected to the second combustion chamber, the air distribution unit is connected to the top of the third combustion chamber, and the air volume delivered by the air distribution unit to the first combustion chamber, the second combustion chamber and the third combustion chamber can be adjusted.

[0008] Preferably, the third combustion chamber is arranged around the outside of the first combustion chamber.

[0009] Preferably, the air distribution unit includes an induced draft fan, which is connected to the first combustion chamber through a first air distribution duct, which is connected to the bottom of the first combustion chamber, and the connecting port is located at the top of the first air distribution duct. A first valve is arranged between the first air distribution duct and the induced draft fan, and the induced draft fan is connected to the second combustion chamber through a second air distribution duct, which is arranged between the second air distribution duct and the induced draft fan, and the induced draft fan is connected to the third combustion chamber through a third air distribution duct, which is connected to the top of the third combustion chamber, and a third valve is arranged between the third air distribution duct and the induced draft fan, and the smoke exhaust port is arranged at the top of the third combustion chamber.

[0010] Preferably, the number of the first air distribution duct, the second air distribution duct, and the third air distribution duct are all multiple, and the multiple first air distribution ducts, the second air distribution ducts, and the third air distribution ducts are uniformly distributed in a circle.

[0011] Preferably, the axes of the first air distribution pipe and the second air distribution pipe are respectively perpendicular to the axis of the first combustion chamber, and the first combustion chamber and the second combustion chamber are coaxially arranged.

[0012] Preferably, the third combustion chamber has a frustum portion at one end away from the first combustion chamber, the third air distribution pipe is connected to the frustum portion, the third air distribution pipe is inclined downward in the direction close to the axis of the third combustion chamber, and the smoke exhaust port is arranged at the end with a smaller diameter of the frustum portion.

[0013] Preferably, the grate is detachably connected to the first combustion chamber.

[0014] Preferably, the smoke exhaust port is provided with a filter assembly.

[0015] Compared with the prior art, the present invention has achieved the following technical effects: the straw bale burning boiler with an independent air supply system of the present invention comprises a first combustion chamber, a second combustion chamber, a third combustion chamber and an air supply unit, the second combustion chamber is located at the bottom of the first combustion chamber, the third combustion chamber is connected to the first combustion chamber, the second combustion chamber and the third combustion chamber are respectively connected to the first combustion chamber, a grate is arranged between the first combustion chamber and the second combustion chamber, the grate can place straw bales, a connecting port is arranged between the first combustion chamber and the third combustion chamber, the third combustion chamber is also provided with a smoke exhaust port, and the first combustion chamber, the second combustion chamber and the third combustion chamber are all provided with temperature sensors; the air supply unit is connected to the bottom of the first combustion chamber, the air supply unit is connected to the second combustion chamber, and the air supply unit is connected to the top of the third combustion chamber, and the air volume delivered by the air supply unit to the first combustion chamber, the second combustion chamber and the third combustion chamber can be adjusted. When using the straw bale burning boiler with an independent air supply system of the present invention, the baled straw is placed in the first combustion chamber, and the air supply unit supplies air to the first combustion chamber to ensure uniform combustion of the straw bale. During the combustion process, the baled straw fuel sequentially undergoes stages such as water evaporation, precipitation of volatiles and coke formation; the coke produced by the combustion falls into the second combustion chamber through the grate and undergoes secondary air supply combustion, and the incompletely burned volatiles enter the third combustion chamber through the connecting port with the flue gas, and the air supply unit supplies air to the third combustion chamber to burn the volatiles in the flue gas again, and the heat generated during the combustion of the straw bale is transferred to the circulating medium through heat exchange for use by the user end. The straw bale burning boiler of the present invention is equipped with an independent air distribution system, and the first combustion chamber, the second combustion chamber, and the third combustion chamber are all connected to the air distribution unit. The whole combustion process is divided into three combustion intervals, namely, primary combustion of straw semi-gasification, secondary combustion of straw charcoal and volatile matter, and re-combustion of volatile matter. The combustion efficiency is improved, while thermal stress concentration is avoided during the bale burning process, and nitrogen oxide emissions are reduced. In addition, temperature sensors are provided in the three combustion chambers to further ensure the boiler temperature and combustion stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0017] Figure 1 It is a structural schematic diagram of a straw bale burning boiler with an independent air distribution system of the present invention;

[0018] Among them, 1 is the first combustion chamber, 2 is the second combustion chamber, 3 is the third combustion chamber, 4 is the air distribution unit, 5 is the grate, 6 is the connecting port, 7 is the temperature sensor, 8 is the smoke exhaust port, 9 is the first air distribution duct, 10 is the first valve, 11 is the second air distribution duct, 12 is the second valve, 13 is the third air distribution duct, 14 is the third valve, and 15 is the straw bale. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The purpose of the present invention is to provide a straw bale burning boiler with an independent air distribution system to solve the problems existing in the above-mentioned prior art, improve the combustion efficiency of straw bale burning, avoid thermal stress concentration during combustion, and reduce nitrogen oxide emissions.

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Please refer to Figure 1 , Figure 1 It is a structural schematic diagram of a straw bale burning boiler with an independent air distribution system according to the present invention.

[0023] The present invention provides a straw bale burning boiler with an independent air distribution system, comprising a first combustion chamber 1, a second combustion chamber 2, a third combustion chamber 3 and an air distribution unit 4, the second combustion chamber 2 is located at the bottom of the first combustion chamber 1, the third combustion chamber 3 is connected to the first combustion chamber 1, the second combustion chamber 2 and the third combustion chamber 3 are respectively connected to the first combustion chamber 1, a grate 5 is arranged between the first combustion chamber 1 and the second combustion chamber 2, the grate 5 can place straw bales, a connecting port 6 is arranged between the first combustion chamber 1 and the third combustion chamber 3, the third combustion chamber 3 is also provided with a smoke exhaust port 8, the first combustion chamber 1, the second combustion chamber 2, and the third combustion chamber 3 are all provided with temperature sensors 7; the air distribution unit 4 is connected to the bottom of the first combustion chamber 1, the air distribution unit 4 is connected to the second combustion chamber 2, and the air distribution unit 4 is connected to the top of the third combustion chamber 3, and the air volume delivered by the air distribution unit 4 to the first combustion chamber 1, the second combustion chamber 2, and the third combustion chamber 3 can be adjusted.

[0024] When using the straw bale burning boiler with an independent air supply system of the present invention, the baled straw is placed in the first combustion chamber 1, and the air supply unit 4 supplies air to the first combustion chamber 1 to ensure uniform combustion of the straw bale. During the combustion process, the baled straw fuel sequentially undergoes stages such as water evaporation, precipitation of volatiles and coke formation; the coke produced by the combustion falls into the second combustion chamber 2 through the grate 5 and undergoes secondary air supply combustion, and the incompletely burned volatiles enter the third combustion chamber 3 along with the flue gas through the connecting port 6, and the air supply unit supplies air to the third combustion chamber 3 to burn the volatiles in the flue gas again, and the heat during the combustion of the straw bale is transferred to the circulating medium through heat exchange for use by the user end. The straw bale burning boiler with an independent air distribution system of the present invention has a first combustion chamber 1, a second combustion chamber 2, and a third combustion chamber 3 which are all connected to an air distribution unit 4. The entire combustion process is divided into three combustion intervals, namely, primary combustion of straw semi-gasification, secondary combustion of straw charcoal and volatile matter, and re-combustion of volatile matter. This improves the combustion efficiency, avoids thermal stress concentration during the bale burning process, and reduces nitrogen oxide emissions. In addition, temperature sensors 7 are provided in the three combustion chambers to ensure boiler temperature and combustion stability.

[0025] Among them, the third combustion chamber 3 is arranged around the outside of the first combustion chamber 1, and accordingly, a plurality of connecting ports 6 are also provided. The plurality of connecting ports 6 are arranged in a circular shape, and the axis of the connecting port 6 is perpendicular to the axis of the first combustion chamber 1 to ensure uniform air supply to the lower part of the straw bale, so that the incompletely burned volatiles can evenly enter the third combustion chamber 3. At the same time, the third combustion chamber 3 is arranged around the outside of the first combustion chamber 1, which can also play a role in keeping the first combustion chamber 1 warm, reduce the heat loss of the first combustion chamber 1, and improve the combustion efficiency.

[0026] Specifically, the air distribution unit 4 includes an induced draft fan, which is connected to the first combustion chamber 1 through a first air distribution pipe 9. The first air distribution pipe 9 is connected to the bottom of the first combustion chamber 1 to provide uniform wind from the outside to the inside for the straw bale, and to perform a semi-gasification combustion on the fuel in the bottom cross section of the straw bale. After the combustion is completed, the fuel at the upper end automatically sinks under the action of gravity and performs the next round of semi-gasification combustion. This cycle is repeated until the fuel is burned out to ensure the stability of the entire straw bale burning process. In this specific embodiment, the distance between the first air distribution pipe 9 and the grate 5 is 5 cm. The connecting port 6 is located at the top of the first air distribution duct 9, a first valve 10 is arranged between the first air distribution duct 9 and the induced draft fan, the induced draft fan is connected to the second combustion chamber 2 through the second air distribution duct 11, a second valve 12 is arranged between the second air distribution duct 11 and the induced draft fan, the induced draft fan is connected to the third combustion chamber 3 through the third air distribution duct 13, the third air distribution duct 13 is connected to the top of the third combustion chamber 3, a third valve 14 is arranged between the third air distribution duct 13 and the induced draft fan, the smoke exhaust port 8 is arranged at the top of the third combustion chamber 3, valves are arranged between each air distribution duct and the induced draft fan, so that the control end can control the air distribution volume of each combustion chamber according to the temperature of the combustion chamber to ensure the stability of the boiler furnace temperature. It should be noted here that the setting of the control end, furnace door and ash cleaning door are all common means of those skilled in the art, which will not be repeated here.

[0027] More specifically, the number of the first air distribution duct 9, the second air distribution duct 11, and the third air distribution duct 13 are all multiple, and the multiple first air distribution ducts 9, the second air distribution duct 11, and the third air distribution duct 13 are uniformly distributed in a circular shape, thereby improving the uniformity of air supply.

[0028] In this specific embodiment, the axes of the first air distribution pipe 9 and the second air distribution pipe 11 are respectively perpendicular to the axis of the first combustion chamber 1, so as to facilitate uniform air supply to the first combustion chamber 1 and the second combustion chamber 2. The first combustion chamber 1 and the second combustion chamber 2 are coaxially arranged, and the coke produced by the combustion in the first combustion chamber 1 falls into the second combustion chamber 2.

[0029] Furthermore, the third combustion chamber 3 has a frustum portion at one end away from the first combustion chamber 1, and the third air distribution pipe 13 is connected to the frustum portion. The third air distribution pipe 13 is inclined downward in the direction close to the axis of the third combustion chamber 3, and the smoke exhaust port 8 is arranged at the end with a smaller diameter of the frustum portion. The third combustion chamber 3 is provided with a frustum portion to facilitate the collection of smoke, and finally the smoke is discharged from the smoke exhaust port 8.

[0030] In addition, the grate 5 is detachably connected to the first combustion chamber 1, which facilitates cleaning and maintenance of the grate 5 to prevent blockage and ensure normal operation of the boiler.

[0031] In order to reduce pollutant emissions, a filter component is provided at the smoke exhaust port 8, which can filter out some pollutants in the smoke and reduce environmental pollution.

[0032] When the straw bale burning boiler with an independent air supply system of the present invention is working, the baled straw is placed in the first combustion chamber 1, and the air supply unit 4 supplies air to the first combustion chamber 1 to ensure uniform combustion of the straw bale. During the combustion process, the baled straw fuel successively undergoes stages such as water evaporation, precipitation of volatiles and coke formation, and the temperature of the first combustion chamber 1 is set to 800°C; the coke produced by the combustion falls into the second combustion chamber 2 through the grate 5, and secondary air supply combustion is carried out, and the temperature of the second combustion chamber 2 is set to 750°C, and the incompletely burned volatiles enter the third combustion chamber 3 with the flue gas through the connecting port 6, and the air supply unit supplies air to the third combustion chamber 3 to burn the volatiles in the flue gas again, and the temperature of the third combustion chamber 3 is set to not less than 700°C, and the opening degree of the valve between the induced draft fan and the air supply duct is adjusted in time according to the temperature of each combustion chamber sensed by the temperature sensor 7 to ensure stable combustion, and the heat in the straw bale combustion process is transferred to the circulating medium through heat exchange for use by the user end.

[0033] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A straw bale burning boiler with an independent air distribution system, characterized in that: The invention comprises a first combustion chamber, a second combustion chamber, a third combustion chamber and an air distribution unit, wherein the second combustion chamber is located at the bottom of the first combustion chamber, the third combustion chamber is connected to the first combustion chamber, the second combustion chamber and the third combustion chamber are respectively connected to the first combustion chamber, a grate is arranged between the first combustion chamber and the second combustion chamber, the grate can be used to place straw bales, a connecting port is arranged between the first combustion chamber and the third combustion chamber, the third combustion chamber is also provided with a smoke exhaust port, and the first combustion chamber, the second combustion chamber and the third combustion chamber are all provided with temperature sensors; the air distribution unit is connected to the bottom of the first combustion chamber, the air distribution unit is connected to the second combustion chamber, the air distribution unit is connected to the top of the third combustion chamber, and the air volume delivered by the air distribution unit to the first combustion chamber, the second combustion chamber and the third combustion chamber can be adjusted; the third combustion chamber is arranged around the outside of the first combustion chamber, and a plurality of connecting ports are arranged circumferentially around the axis of the first combustion chamber.

2. The straw bale burning boiler with independent air distribution system according to claim 1, characterized in that: The air distribution unit includes an induced draft fan, which is connected to the first combustion chamber through a first air distribution duct, the first air distribution duct is connected to the bottom of the first combustion chamber, the connecting port is located at the top of the first air distribution duct, a first valve is arranged between the first air distribution duct and the induced draft fan, the induced draft fan is connected to the second combustion chamber through a second air distribution duct, a second valve is arranged between the second air distribution duct and the induced draft fan, the induced draft fan is connected to the third combustion chamber through a third air distribution duct, the third air distribution duct is connected to the top of the third combustion chamber, a third valve is arranged between the third air distribution duct and the induced draft fan, and the smoke exhaust port is arranged at the top of the third combustion chamber.

3. The straw bale burning boiler with independent air distribution system according to claim 2, characterized in that: The number of the first air distribution duct, the second air distribution duct, and the third air distribution duct are all multiple, and the multiple first air distribution ducts, the second air distribution ducts, and the third air distribution ducts are uniformly distributed in a circle.

4. The straw bale burning boiler with independent air distribution system according to claim 3, characterized in that: The axes of the first air distribution pipe and the second air distribution pipe are respectively perpendicular to the axis of the first combustion chamber, and the first combustion chamber and the second combustion chamber are coaxially arranged.

5. The straw bale burning boiler with independent air distribution system according to claim 3, characterized in that: The third combustion chamber has a frustum at one end away from the first combustion chamber, the third air distribution pipe is connected to the frustum, the third air distribution pipe is tilted downward toward the direction close to the axis of the third combustion chamber, and the smoke exhaust port is arranged at the end of the frustum with a smaller diameter.

6. The straw bale burning boiler with an independent air distribution system according to any one of claims 1 to 5, characterized in that: The grate is detachably connected to the first combustion chamber.

7. The straw bale burning boiler with an independent air distribution system according to any one of claims 1 to 5, characterized in that: The smoke exhaust port is provided with a filter assembly.

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