Corner tube type biomass boiler and energy-saving heat supply system

Abstract

The invention discloses a corner tube type biomass boiler and an energy-saving heat supply system.The boiler comprises a horizontal boiler body, a combustor, a plurality of evaporators and a denitration dust removal device, and the horizontal boiler body is provided with a transversely-arranged hearth, a first heat transfer area, a second heat transfer area, a first connecting flue, a second connecting flue, a third connecting flue and a plurality of ash falling hoppers; the hearth is provided with a burner installation opening, a first air inlet and a second air inlet. According to the boiler, the hearth, the first heat transfer area and the second heat transfer area are arranged in a modularized mode, the ash falling hopper, the evaporator, the denitration dust removal device and other structures are matched, the boiler is arranged in a horizontal structure, all the components are modularly delivered, the field installation period can be greatly shortened, meanwhile, the boiler body is subjected to multi-stage heat transfer and ash falling treatment, and the boiler is convenient to use. According to the utility model, the heat transfer process is not influenced by fly ash, and flames can be prevented from directly scouring the heating surface in the hearth, so that the hearth is prevented from slagging or coking, and a better heat exchange effect is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of biomass boilers, and in particular to a corner tube biomass boiler and an energy-saving heating system. Background Art

[0002] A biomass boiler is a boiler that uses biomass energy as fuel. In general, biomass boilers use a screw feeder to feed biomass fuel into the furnace, where it is gradually preheated, dried, ignited, and burned due to the action of high-temperature flue gas and primary air. A large amount of volatile matter is precipitated during this process, and the combustion is intense. The high-temperature flue gas generated flushes the main heating surface of the boiler, then enters the economizer and air preheater at the rear heating surface of the boiler, then enters the dust collector, and is finally discharged into the atmosphere through the chimney. The ungasified fuel moves toward the rear of the grate until it is burned out, and the remaining small amount of ash falls into the slag removal port behind the grate.

[0003] Since most biomass fuels are burned directly or after gasification, they always carry some fly ash or small ungasified carbon residues, which leads to the fact that most of the current biomass boilers are vertical in structure, so that the fly ash or carbon residue can fall back into the furnace and burn out again. Considering the heat transfer and ash removal effects, a higher combustion area or heat transfer area is often set, such as CN116241876A-a biomass boiler structure with a gasification chamber, CN117823886A-gas-solid two-phase high-efficiency combustion biomass boiler, etc. However, the overall height of the vertical biomass boiler is relatively high, and it is generally installed on-site, resulting in a long on-site installation cycle, which affects the normal heat use of users. At present, there is little research on horizontal biomass boilers, and there are few related literature reports. There is an urgent need for a horizontal biomass boiler that is easy to transport and maintain and has a good heat transfer effect. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, one of the objectives of the present invention is to provide a corner tube biomass boiler to solve the above-mentioned traditional problems.

[0005] A second object of the present invention is to provide an energy-saving heating system using the corner tube biomass boiler.

[0006] One of the purposes of the present invention is achieved by the following technical solution: A corner tube biomass boiler comprises a horizontal boiler body, a burner, a plurality of evaporators and a de-ashing and dust removing device. The horizontal boiler body is provided with a transversely arranged furnace, a first heat transfer zone, a second heat transfer zone, a first connecting flue, a second connecting flue, a third connecting flue and a plurality of ash hoppers. The furnace is provided with a burner mounting port, a first air inlet and a second air inlet. The first air inlet is used to connect with a cracking gas outlet. The side of the furnace is connected with the first heat transfer zone through the first connecting flue. The first heat transfer zone is connected with the second heat transfer zone through the second connecting flue. The second heat transfer zone is connected with the de-ashing and dust removing device through the third connecting flue. The first heat transfer zone is provided with a plurality of first evaporator mounting ports for installing the evaporator. The second heat transfer zone is provided with a plurality of second evaporator mounting ports for installing the evaporator.

[0007] Preferably, the horizontal boiler body is a serpentine plane bending structure composed of a boiler drum, a main membrane water-cooled wall, a lower header, an upper header and a convection tube bundle. The boiler drum is arranged on the top of the horizontal boiler body, the lower header and the upper header are arranged at the opposite ends of the main membrane water-cooled wall, and the convection tube bundle is used for convection communication between the boiler drum and the lower header and the upper header.

[0008] Preferably, the horizontal boiler body is also provided with a water connecting pipe and a steam connecting pipe, one end of the water connecting pipe is connected to the bottom of the evaporator, one end of the steam connecting pipe is connected to the top of the evaporator, and the other end of the steam connecting pipe is connected to the boiler drum.

[0009] Preferably, the horizontal boiler body is further provided with a bypass flue, one end of the bypass flue is connected to the second connecting flue, the other end of the bypass flue is connected to the third connecting flue, and a control valve is installed on the bypass flue.

[0010] Preferably, the evaporator includes a water collecting pipe, a water distribution pipe, a secondary membrane water-cooled wall connecting the water collecting pipe and the water distribution pipe, and a closely packed convection tube bundle, the water distribution pipe is provided with a first water pipe and a second water pipe, the first water pipe is an arched pipe, the second water pipe is a straight pipe, and the first water pipe and the second water pipe are staggered.

[0011] Preferably, the desulfurization and dust removal device includes a cyclone dust collector, a fourth connecting flue, a high-temperature desulfurization device, a high-temperature energy saver, a fifth connecting flue, a low-temperature energy saver, a sixth connecting flue, a low-temperature desulfurization device and a bag dust collector arranged in sequence along the flue gas flow.

[0012] Preferably, the corner tube biomass boiler also includes a biomass cracking device, which includes a feeding mechanism, a feeding chamber, a cracking gasification chamber, a burnout chamber and a movable material bed. The feeding mechanism includes a feeding hopper and an elevator. The top of the feeding chamber is provided with a feeding port connected to the elevator; the side top of the cracking gasification chamber is provided with a cracking gas outlet, the movable material bed is arranged at the bottom of the biomass cracking device, and an independently adjustable gasifying agent inlet is provided below the movable material bed; the movable material bed is divided into an inclined portion and a lying portion, the inclined portion is arranged at the bottom of the cracking gasification chamber, the inclined portion is inclined from the feeding chamber to the burnout chamber, the lying portion is arranged at the bottom of the burnout chamber, and the burnout chamber is provided with a connecting port connected to the second air inlet.

[0013] Preferably, a first partition wall is provided between the feed chamber and the cracking gasification chamber, a second partition wall is provided between the cracking gasification chamber and the burnout chamber, and the bottom of the feed chamber, the bottom of the cracking gasification chamber, and the bottom of the burnout chamber are interconnected.

[0014] Preferably, the inclination angle of the inclined portion is 20-45°.

[0015] The second object of the present invention is achieved by adopting the following technical solution: An energy-saving heating system comprises the corner tube biomass boiler described above.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The corner tube biomass boiler of the present invention adopts a modular setting of the furnace, the first heat transfer zone, and the second heat transfer zone, and is combined with structures such as an ash hopper, an evaporator, and a de-ashing and dust removal device, so that the boiler is arranged in a horizontal structure. All components are modularized when shipped, which can greatly reduce the on-site installation cycle. At the same time, the boiler body undergoes multi-stage heat transfer and ash removal treatments to ensure that the heat transfer process is not affected by fly ash, and the flame can be prevented from directly scouring the heating surface in the furnace to prevent slagging or coking in the furnace, thereby achieving a better heat exchange effect.

[0017] 2. The burner of the present invention adopts a biomass thermal cracking burner, which can effectively utilize biomass resources such as agricultural and forestry wastes, reduce environmental pollution, and improve energy utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural view of the corner tube biomass boiler of the present invention; Figure 2 for Figure 1 A first cross-sectional view of a corner tube biomass boiler is shown; Figure 3 for Figure 1A second cross-sectional view of the corner tube biomass boiler shown; Figure 4 for Figure 1 A third cross-sectional view of the corner tube biomass boiler shown; Figure 5 for Figure 1 A fourth cross-sectional view of the corner tube biomass boiler shown; Figure 6 for Figure 1 A fifth cross-sectional view of the corner tube biomass boiler shown; Figure 7 It is a schematic diagram of the connection structure of the corner tube type biomass boiler of the present invention; Figure 8 for Figure 7 A schematic diagram of the three-dimensional structure of the evaporator shown; Fig. 9 for Figure 8 A first cross-sectional view of the evaporator is shown; Fig.10 for Figure 8 A second cross-sectional view of the evaporator is shown.

[0019] In the figure: 10, biomass cracking device; 11, feeding mechanism; 12, feeding chamber; 13, cracking gasification chamber; 14, burnout chamber; 15, movable material bed; 20, horizontal boiler body; 21, drum; 22, main membrane water-cooled wall; 23, lower header; 24, upper header; 25, convective tube bundle; 26, furnace; 27, first heat transfer zone; 28, second heat transfer zone; 29, ash hopper; 30, burner; 40, evaporator; 41, water collecting pipe; 42, water distribution pipe; 43, secondary membrane water-cooled wall; 44, close-packed convection tube bundle; 50, desulfurization device; 51, cyclone dust collector; 52, high-temperature desulfurization device; 53, high-temperature energy saver; 54, low-temperature energy saver; 55, low-temperature desulfurization device; 56, bag filter; 60, bypass flue. DETAILED DESCRIPTION

[0020] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0021] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0022] In the description of the present invention, it should be understood that when an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be intermediate elements at the same time. On the contrary, when an element is said to be "directly" connected to another element, there are no intermediate elements.

[0023] See also Figure 1-Figure 10 , which is a corner tube biomass boiler of a preferred embodiment of the present invention, is used to provide hot water or steam for users. Specifically, the corner tube biomass boiler includes a biomass cracking device 10, a horizontal boiler body 20 connected to the biomass cracking device 10, a burner 30 installed on the horizontal boiler body 20, a plurality of evaporators 40, and a desulfurization and dust removal device 50.

[0024] like Figure 2 and Figure 7 As shown, the biomass cracking device 10 is used to thermally crack the biomass fuel transported in. Specifically, the biomass cracking device 10 includes a feeding mechanism 11, a feeding chamber 12, a cracking gasification chamber 13, a burnout chamber 14 and a movable material bed 15. The feeding mechanism 11 includes a feeding hopper and an elevator. The feeding hopper is used to load the biomass fuel. The top of the feeding chamber 12 is provided with a feeding port connected to the elevator. A first partition wall is provided between the feeding chamber 12 and the cracking gasification chamber 13. A second partition wall is provided between the cracking gasification chamber 13 and the burnout chamber 14. The bottom of the feeding chamber 12, the bottom of the cracking gasification chamber 13, and the bottom of the burnout chamber 14 are interconnected. The side top of the cracking gasification chamber 13 is provided with a cracking gas outlet. The movable material bed 15 is provided at the top of the biomass fuel. At the bottom of the cracking device 10, an independently adjustable gasifying agent inlet is provided below the movable material bed 15, which is used to supply the gasifying agent to the cracking gasification chamber 13. The movable material bed 15 is divided into an inclined portion and a lying portion. The inclined portion is provided at the bottom of the cracking gasification chamber 13. The inclined portion is inclined from the feed chamber 12 to the burnout chamber 14, such as an inclination angle of 20-45°, preferably 30°, which is convenient for gradually conveying the material for cracking. The lying portion is provided at the bottom of the burnout chamber 14. The burnout chamber 14 is provided with a connecting port connected to the horizontal boiler body 20, which is used to receive the residual carbon or fly ash falling from the horizontal boiler body 20 for re-cracking and combustion, and the cracking gas is conveyed to the horizontal boiler body 20 through the connecting port or the air inlet for combustion.

[0025] The function of the pyrolysis and gasification chamber is to enable the biomass fuel to be burned at low to medium temperature (300℃~450℃) with oxygen depletion and to be efficiently pyrolyzed and gasified, to provide the heat required for pyrolysis and gasification of the biomass molding fuel, and to produce biomass fuel gas. The thickness of the biomass fuel in the pyrolysis and gasification chamber is maintained at 400~500mm, so that the fine dust particles produced after gasification are bonded into large particles by the sticky substances precipitated by the pyrolysis and gasification of the fuel in the material bed. Most of the particles enter the combustion chamber and are discharged as slag after combustion, which greatly reduces the content of particles in the combustible gas entering the boiler furnace 26, achieving the effect of clean combustion and clean emission, and meeting the national environmental protection emission standards. An independently adjustable air inlet chamber is provided below the movable material bed 15 in the pyrolysis and gasification chamber to promote the gasification effect of the fuel in the material bed, and at the same time play a role in promoting the pyrolysis and gasification of the fuel, so that the fuel can be evenly transported to the material bed, so as to achieve the gasification agent required for the pyrolysis and gasification of the fuel in the material bed and be evenly distributed, which is convenient for the efficient pyrolysis and gasification of the biomass fuel. The gasifying agent (the gasifying agent is a mixture of air and water vapor, with a volume ratio of 70-80% air and 20-30% water vapor) is transported through the lower air inlet chamber of the pyrolysis gasification material bed with a high pressure head (above 8kPa), so that the tar and other substances released by the biomass fuel during pyrolysis enter the upper space of the pyrolysis gasification chamber under the impact of the gasifying agent. The temperature of this part of the space is above 300°C, which is higher than the tar precipitation and condensation temperature (the tar condensation temperature is about 200°C), so that the biomass fuel can be efficiently utilized after pyrolysis and gasification. After the fuel in the material bed of the pyrolysis gasification chamber is pyrolyzed and gasified, the slag is discharged online through the movable material bed 15.

[0026] In other embodiments, the biomass cracking device 10 may also be a cracking gas delivery pipe or a fuel gas containing fly ash, which will not be described in detail herein.

[0027] For example Figure 2-Figure 7As shown, the horizontal boiler body 20 is used to ignite and burn the cracking gas and exchange heat with the high-temperature flue gas to prepare hot water or high-temperature steam. The horizontal boiler body 20 is roughly arranged in a horizontal structure. In the cross section, the horizontal boiler body 20 is roughly composed of a serpentine plane bending structure composed of a drum 21, a main membrane water-cooled wall 22, a lower header 23, an upper header 24 and a convection tube bundle 25, which is convenient for heat transfer with the high-temperature flue gas and combustion of the carbon slag carried by the flue gas. Among them, the drum 21 is arranged on the top of the horizontal boiler body 20, the lower header 23 and the upper header 24 are arranged at the opposite ends of the main membrane water-cooled wall 22, and the convection tube bundle 25 is used for convection communication between the drum 21 and the lower header 23 and the upper header 24. In one embodiment, the horizontal boiler body 20 is provided with a horizontal The furnace 26, the first heat transfer zone 27, the second heat transfer zone 28, the first connecting flue, the second connecting flue, the third connecting flue and several ash hoppers 29 are arranged in the horizontal direction. The furnace 26 is provided with a burner 30 installation port, a first air inlet and a second air inlet. The burner 30 installation port is used to install the burner 30. The first air inlet is used to connect with the cracking gas outlet of the cracking gasification chamber 13. The second air inlet is used to connect with the connecting port of the burnout chamber 14. The ash hoppers 29 are evenly distributed at the bottom of the horizontal boiler body 20 to facilitate the collection of fly ash. The side of the furnace 26 is connected with the first heat transfer zone 27 through the first connecting flue, the first heat transfer zone 27 is connected with the second heat transfer zone 28 through the second connecting flue, and the second heat transfer zone 28 is connected with the de-ashing dust removal device 50 through the third connecting flue. It can be understood that the furnace 26, the first heat transfer zone 27, and the second heat transfer zone 28 are connected side by side on the same plane to form a serpentine plane bending structure. The de-pinning dust removal device 50 is arranged according to the specific position to facilitate the compact arrangement of the overall equipment. The first heat transfer zone 27 is provided with a plurality of first evaporator 40 installation ports for installing the evaporator 40, and the second heat transfer zone 28 is provided with a plurality of second evaporator 40 installation ports for installing the evaporator 40, so that each evaporator 40 is installed side by side, which is convenient for gradual heat transfer and improves the heat transfer effect, and also facilitates modular shipment of each area, which is convenient for transportation and convenient on-site installation. In addition, the evaporator 40 is easy to dismantle and repair to avoid dust and carbon accumulation that seriously affects heat transfer.

[0028] In this embodiment, the furnace 26 is rectangular. In order to prevent the flame from directly scouring the heating surface and to prevent the furnace 26 from slagging or coking, the length of the furnace 26 is 2-5 times the length of the flame of the burner 30. Preferably, the size of the furnace 26 is 9180*2210*22660mm, and the maximum allowable size of the flame of the burner 30 is Φ2000*7500mm. A soot blower interface is reserved in the convection area of ​​the boiler body, and soot blowing equipment can be installed to blow the fly ash in the boiler.

[0029] In other embodiments, the horizontal boiler body 20 is further provided with a bypass flue 60, one end of the bypass flue 60 is connected to the second connecting flue, and the other end of the bypass flue 60 is connected to the third connecting flue, and a control valve is installed on the bypass flue 60, wherein the second connecting flue is provided with a first pressure transmitter, a first thermometer and a first temperature sensor, and the third connecting flue is provided with a second pressure transmitter, a second thermometer and a second temperature sensor. When the second temperature sensor detects that the flue gas temperature in the third connecting flue does not meet the desulfurization temperature requirement of the desulfurization dust removal device 50, and the first temperature sensor detects that the flue gas temperature in the second connecting flue meets the desulfurization temperature requirement, the control valve is opened to transport the high-temperature flue gas in the second connecting flue to the third connecting flue, thereby ensuring the normal operation of the desulfurization dust removal device 50.

[0030] When the boiler is running at low load, due to the reduction of boiler heat load, the outlet flue gas temperature after the boiler evaporation heating surface will also decrease. In order to ensure that the denitration reaction can proceed normally, the user must select a low-temperature denitration catalyst, and the denitration operation cost will increase. When the boiler is at full load, the flue gas temperature will rise again, and the low-temperature denitration catalyst cannot meet the denitration requirements. Therefore, during the boiler load change process, part of the high-temperature flue gas can be extracted from the position of the second connecting flue into the denitration dust removal device 50, so as to adjust the reaction temperature in the device and ensure that the reaction temperature entering the denitration dust removal device 50 is within the range of 280°C to 310°C, so as to ensure efficient catalysis, so that the boiler can also ensure the normal operation of the denitration device during the load change process.

[0031] In this embodiment, the horizontal boiler body 20 is also provided with a water connecting pipe and a steam connecting pipe. One end of the water connecting pipe is connected to the water supply end, and the other end of the water connecting pipe is connected to the bottom of the evaporator 40 to provide a reliable water supply for the evaporator 40. One end of the steam connecting pipe is connected to the top of the evaporator 40, and the other end of the steam connecting pipe is connected to the drum 21 to transport the water vapor generated by the evaporator 40 to the drum 21 for steam-water separation.

[0032] In one embodiment, if Figure 8-Figure 10As shown, the evaporator 40 is an external evaporator 40 structure. Specifically, the evaporator 40 includes a water collecting pipe 41, a water distribution pipe 42, a secondary membrane water-cooled wall 43 connecting the water collecting pipe 41 and the water distribution pipe 42, and a close-packed convection tube bundle 44. The water distribution pipe 42 is provided with a first water pipe and a second water pipe. The first water pipe is an arched pipe, and the second water pipe is a straight pipe. The first water pipe and the second water pipe are staggered to form a high-low staggered structure, which increases the dust-falling space below and is more conducive to the sedimentation of dust in the flue gas. Optionally, the opposite ends of the secondary membrane water-cooled wall 43 are bent outward to increase the dust-falling space between the close-packed convection tube bundle 44, and also buffer the water in the tube to improve the heat exchange performance of its outer wall, that is, to reduce the middle space to facilitate the heat exchange in the middle, wherein the angle of the opposite ends of the secondary membrane water-cooled wall 43 bending outward is 140°-160°.

[0033] In one embodiment, if Figure 7 As shown, the desulfurization and dust removal device 50 includes a cyclone dust collector 51, a fourth connecting flue, a high-temperature desulfurization device 52, a high-temperature energy saver 53, a fifth connecting flue, a low-temperature energy saver 54, a sixth connecting flue, a low-temperature desulfurization device 55 and a bag dust collector 56 arranged in sequence along the flow of flue gas. The cyclone dust collector 51 is connected to one end of the third connecting flue, and the outlet of the bag dust collector 56 is connected to the chimney. The above device removes the desulfurization and dust from the flue gas through the dust collector, the desulfurization device, etc., so that it meets the standard for external discharge. At the same time, an energy saver is set to recover the waste heat of the flue gas to improve the energy saving effect of the system. Among them, the high-temperature energy saver 53 and the low-temperature energy saver 54 are both composed of light pipe serpentine pipes.

[0034] Its working principle is: (1) Smoke flow: Biomass such as agricultural and forestry waste is transported to the biomass cracking device 10 for thermal cracking. The cracking gas enters the horizontal boiler body 20 through the first air inlet (air enters from the other side and mixes with the cracking gas), and is ignited and burned by the burner 30. The high-temperature flue gas heats the main membrane water-cooled wall 22 of the furnace 26, and then flows into the first heat transfer area 27 through the first connecting flue, and then transfers the heat to the evaporator 40 and the main membrane water-cooled wall 22 in turn, and then flows into the second heat transfer area 28 through the second connecting flue, and transfers the heat to the evaporator 40 and the main membrane water-cooled wall 22 again. Then, it enters the denitrification dust removal device 50 for dust removal, denitrification and waste heat recovery. During the flow of flue gas, most of the fly ash and residual carbon fall into the ash hopper 29 for subsequent treatment, and a small part of the fly ash is treated by the denitrification dust removal device 50.

[0035] (2) System water flow: After the pure water passes through the low-temperature economizer 54 and the high-temperature economizer 53 in turn for waste heat recovery, it passes through the second heat transfer zone 28 and the evaporator 40 on the first heat transfer zone 27 for convection heat exchange. The steam obtained by the evaporator 40 is transported to the drum 21 for steam-water separation. The separated hot water is then diverted to each convection tube bundle and enters each water-cooled wall and the evaporator 40 for heat exchange again, and the high-temperature steam is output to the outside.

[0036] Compared with the biomass corner tube boiler and biomass SZS boiler currently on the market, the boiler of the present invention has the following characteristics: 1. At present, the corner tube furnaces producing substances in the market are mainly vertical. The overall layout of the boiler of the present invention is a horizontal corner tube boiler, which occupies a small area and has low on-site installation and construction costs.

[0037] 2. All parts of the boiler are modularized, which can greatly reduce the on-site installation period. At the same time, the modular design can be combined more flexibly under the premise of meeting the maximum transportation size. Different modules can be combined according to needs to adapt to different heat loads.

[0038] 3. Compared with the convection tube bundle of the conventional biomass SZS boiler, the lower header of the convection tube bundle of the boiler of the present invention adopts a high-low staggered arrangement, which increases the ash falling space at the bottom and is more conducive to the sedimentation of dust in the flue gas. At the same time, an ash falling hopper 29 is arranged at the bottom of the boiler to facilitate the collection and transportation of ash during the operation of the boiler. A screw conveyor and a scraper conveyor can be installed at the bottom of the ash hopper to improve the degree of mechanization and reduce the work intensity of the boiler operator.

[0039] 4. A flue gas bypass interface is provided in the flue connecting the boiler body and the external evaporator 40 .

[0040] When the boiler is running at low load, the outlet flue gas temperature after the boiler evaporation heating surface will also decrease due to the reduction of boiler heat load. To ensure that the denitration reaction can proceed normally, the user must use a low-temperature denitration catalyst, and the denitration operation cost will increase. When the boiler is at full load, the flue gas temperature will rise again, and the low-temperature denitration catalyst cannot meet the denitration requirements.

[0041] Therefore, during the load change process of the boiler, part of the high-temperature flue gas can be extracted from this position to enter the SCR device or the cyclone dust collector 51 before the SCR device, so as to adjust the reaction temperature in the SCR device. The reaction temperature entering the SCR device is guaranteed to be within the range of 280°C to 310°C to ensure efficient catalysis, so that the boiler can also ensure the normal operation of the denitrification device during the load change process.

[0042] 5. The burner 30 uses a biomass thermal cracking burner 30, which can effectively utilize biomass resources such as agricultural and forestry wastes, reduce environmental pollution, and improve energy utilization.

[0043] In another embodiment, the present invention also provides an energy-saving heating system, including the corner tube biomass boiler of the above embodiment, which is connected to a heating pipeline to achieve a better energy-saving heating effect. The device is also provided with corresponding control instruments and control equipment to facilitate automatic control thereof, and is coated with an insulation layer on the outside to improve its thermal efficiency. The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0044] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A corner tube biomass boiler, characterized in that: The invention comprises a horizontal boiler body, a burner, a plurality of evaporators and a de-powder dust removal device. The horizontal boiler body is provided with a transversely arranged furnace, a first heat transfer zone, a second heat transfer zone, a first connecting flue, a second connecting flue, a third connecting flue and a plurality of ash hoppers. The furnace is provided with a burner installation port, a first air inlet and a second air inlet. The first air inlet is used to connect with a cracking gas outlet. The side of the furnace is connected with the first heat transfer zone through the first connecting flue. The first heat transfer zone is connected with the second heat transfer zone through the second connecting flue. The second heat transfer zone is connected with the de-powder dust removal device through the third connecting flue. The first heat transfer zone is provided with a plurality of first evaporator installation ports for installing the evaporator. The second heat transfer zone is provided with a plurality of second evaporator installation ports for installing the evaporator.

2. The corner tube biomass boiler according to claim 1, characterized in that: The horizontal boiler body is a serpentine plane bending structure composed of a boiler drum, a main membrane water-cooled wall, a lower header, an upper header and a convection tube bundle. The boiler drum is arranged on the top of the horizontal boiler body, the lower header and the upper header are arranged at the opposite ends of the main membrane water-cooled wall, and the convection tube bundle is used for convection communication between the boiler drum and the lower header and the upper header.

3. The corner tube biomass boiler according to claim 2, characterized in that: The horizontal boiler body is also provided with a water connecting pipe and a steam connecting pipe, one end of the water connecting pipe is connected to the bottom of the evaporator, one end of the steam connecting pipe is connected to the top of the evaporator, and the other end of the steam connecting pipe is connected to the boiler drum.

4. The corner tube biomass boiler according to claim 1, characterized in that: The horizontal boiler body is also provided with a bypass flue, one end of which is connected to the second connecting flue, and the other end of which is connected to the third connecting flue. A control valve is installed on the bypass flue.

5. The corner tube biomass boiler according to claim 1, characterized in that: The evaporator includes a water collecting pipe, a water distribution pipe, a secondary membrane water-cooled wall connecting the water collecting pipe and the water distribution pipe, and a closely packed convection tube bundle. The water distribution pipe is provided with a first water pipe and a second water pipe. The first water pipe is an arched pipe, and the second water pipe is a straight pipe. The first water pipe and the second water pipe are staggered.

6. The corner tube biomass boiler according to claim 1, characterized in that: The desulfurization and dust removal device includes a cyclone dust collector, a fourth connecting flue, a high-temperature desulfurization device, a high-temperature energy saver, a fifth connecting flue, a low-temperature energy saver, a sixth connecting flue, a low-temperature desulfurization device and a bag dust collector which are arranged in sequence along the flow of flue gas.

7. The corner tube biomass boiler according to claim 1, characterized in that: The corner tube biomass boiler also includes a biomass cracking device, which includes a feeding mechanism, a feeding chamber, a cracking gasification chamber, a burnout chamber and a movable material bed. The feeding mechanism includes a feeding hopper and an elevator. The top of the feeding chamber is provided with a feeding port connected to the elevator; the side top of the cracking gasification chamber is provided with a cracking gas outlet, the movable material bed is arranged at the bottom of the biomass cracking device, and an independently adjustable gasification agent inlet is arranged below the movable material bed; the movable material bed is divided into an inclined portion and a lying portion, the inclined portion is arranged at the bottom of the cracking gasification chamber, the inclined portion is inclined from the feeding chamber to the burnout chamber, the lying portion is arranged at the bottom of the burnout chamber, and the burnout chamber is provided with a connecting port connected to the second air inlet.

8. The corner tube biomass boiler according to claim 7, characterized in that: A first partition wall is provided between the feed chamber and the cracking and gasification chamber, a second partition wall is provided between the cracking and gasification chamber and the burnout chamber, and the bottom of the feed chamber, the bottom of the cracking and gasification chamber, and the bottom of the burnout chamber are interconnected.

9. The corner tube biomass boiler according to claim 7, characterized in that: The inclination angle of the inclined portion is 20-45°.

10. An energy-saving heating system, characterized in that: It comprises a corner tube biomass boiler as described in any one of claims 1 to 9.

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