Biomass boiler capable of preventing flag type heating surface from coking

Abstract

The biomass boiler capable of preventing the flag type heating surface from coking comprises a boiler body and a smoke discharging mechanism, a vertical smoke channel is arranged in the boiler body, one end of the vertical smoke channel is communicated with a hearth, and the other end of the vertical smoke channel is communicated with the flag type heating surface and a channel of the flag type heating surface. The flag-type heating surface is communicated with the channel of the flag-type heating surface and is communicated with the smoke exhaust mechanism; a vertical membrane type wall smoke channel and a smoke transfer chamber are additionally arranged between the membrane type wall hearth and the flag type heating surface as well as between the flag type heating surface and the channel; high-temperature flue gas enters the vertical membrane type wall flue gas channel from the hearth through the slag solidification pipe bundle, is further fully burnt out and is cooled to below 700 DEG C which is far lower than the ash melting point, so that the high-temperature flue gas cannot be coked and blocked on the flag type heating surface pipe, and the operation period of the boiler is greatly prolonged. After smoke enters the smoke transfer chamber, the speed of the smoke is reduced, the smoke is turned upwards and enters the flag type heating surface and a channel thereof, part of large-particle dust is separated due to the inertia separation effect, and abrasion to a flag type heating surface tube bundle and accumulated dust are reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of biomass boiler, specifically, especially relates to a biomass boiler capable of preventing coking of flag type heating surface. BACKGROUND

[0002] Biomass briquettes are made of agricultural and forestry wastes such as crop straws, sugar cane residues, rice husks, tree branches, tree barks and wood chips as raw materials through processes such as crushing, drying, mixing and extruding, and are mainly used to replace traditional fossil energy (such as coal, oil and natural gas) and are a new type of renewable clean fuel with broad prospects. However, since biomass contains alkali metal elements such as potassium, the ash melting point of the ash after combustion is low, which causes coking and ash deposition on the heating surface of the boiler, resulting in insufficient output of the boiler, decreased thermal efficiency, increased flue gas temperature and flue gas resistance, affecting the safe and economic operation of the boiler, and in severe cases, the flue gas passage of the entire convection heating surface is blocked, causing the boiler to be forced to shut down. Therefore, for a biomass boiler, reducing the outlet temperature of the furnace to be much lower than the ash melting point can effectively prevent coking at the tube bundle of the convection heating surface.

[0003] The corner tube boiler originated from Denmark and was introduced into China in the 1980s and is mainly used for coal-fired boilers. Since the boiler has the advantages of 1) simple and compact structure, 2) good overall seismic resistance, 3) membrane wall structure around the periphery, good sealing, 4) flag type heating surface structure for the convection heating surface, good heat transfer effect, 5) self-supporting structure for the boiler without steel frame, only the platform ladder has a steel frame, and low steel consumption, the boiler has been widely promoted in China and has been applied to biomass boilers. However, for coal-fired boilers, since the ash melting point of the ash is high, the flue gas from the furnace directly enters the flag type heating surface tube bundle after passing through the slag condensing tube bundle, which does not cause coking. If the boiler is directly used for a biomass boiler, since the flue gas temperature at the outlet of the furnace is high and the ash melting point of the biomass ash is low, the flue gas directly enters the flag type heating surface tube bundle after coming out of the furnace, which easily causes coking. The coking blocks the entire flue gas passage, which further causes forced shutdown.

[0004] If the height of the furnace is increased to reduce the outlet temperature of the furnace, the manufacturing cost of the boiler and the capital investment of the customer will be greatly increased. Therefore, how to solve the problem of easy coking caused by the flue gas directly entering the flag type heating surface tube bundle after coming out of the furnace is an important problem that needs to be solved in the development of biomass boilers. UTILITY MODEL CONTENTS

[0005] The utility model discloses a biomass boiler of preventing flag type heating surface coking which is proposed to solve the shortcomings in the prior art, comprising a boiler body and a smoke exhaust mechanism, further comprising a vertical flue gas passage arranged inside the boiler body, wherein one end of the vertical flue gas passage is in communication with a hearth arranged inside the boiler body, and the other end is in communication with a flag type heating surface and its passage arranged inside the boiler body, and the flag type heating surface and its passage are in communication with the smoke exhaust mechanism.

[0006] Preferably, the vertical flue gas passage is further provided with a slag condensing pipe bundle between the hearths.

[0007] Preferably, the vertical flue gas passage is provided with a smoke turning chamber at the end away from the hearth, and the high-temperature flue gas in the hearth is transferred to the flag type heating surface and its passage through the smoke turning chamber after being cooled by the vertical flue gas passage.

[0008] Preferably, the smoke exhaust mechanism comprises a boiler flue gas outlet in communication with the flag type heating surface and its passage, and the boiler flue gas outlet is in communication with a high / low temperature economizer arranged outside the boiler body through a communication pipeline.

[0009] Preferably, the high / low temperature economizer is provided with the communication pipeline at the end away from the boiler flue gas outlet.

[0010] Preferably, the boiler body comprises a boiler drum, a spreader, a chain grate, and a membrane wall hearth.

[0011] The boiler drum is arranged at the upper part of the front end of the boiler body.

[0012] The spreader is arranged at the middle lower part of the front end of the boiler body, and the upper part of the spreader is in communication with a charging port, and the lower part of the spreader is matched with the chain grate arranged at the lower end of the boiler body.

[0013] Preferably, the outer side of the boiler body is provided with a platform steel frame and a platform escalator.

[0014] Preferably, the chain grate is provided with a grate air chamber at both sides of the bottom.

[0015] Preferably, the chain grate is provided with a slag extractor at the bottom.

[0016] Compared with existing technologies, the beneficial effects of this invention are as follows: By adding a vertical membrane wall flue gas passage and a flue gas transfer chamber between the membrane furnace and the flag-type heating surface and its channels, high-temperature flue gas enters the vertical membrane wall flue gas passage from the furnace through the slag-forming tube bundle, where it undergoes further and more complete combustion and is cooled to below 700°C, far below the ash melting point. This prevents coking and blockage of the entire flue gas passage on the flag-type heating surface tubes, thus significantly extending the boiler's operating cycle. After entering the flue gas transfer chamber, the flue gas velocity decreases and it turns upwards into the flag-type heating surface and its channels. Due to inertial separation, some large dust particles are separated, reducing wear and ash accumulation on the flag-type heating surface tube bundle. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of a biomass boiler that prevents coking on the flag-type heating surface, as proposed in this utility model.

[0018] In the diagram, 1. Boiler drum; 2. Platform ladder; 3. Steel frame; 4. Feeder; 5. Chain grate; 6. Membrane furnace; 7. Slag-collecting tube bundle; 8. Vertical membrane wall flue gas passage; 9. Flag-type heating surface and its passage; 10. Flue gas chamber; 11. Boiler flue gas outlet; 12. High and low temperature economizers; 13. Air preheater; 14. Thermal insulation layer; 15. Protective plate. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0020] Referring to the figure, this embodiment provides a biomass boiler for preventing coking on the flag-type heating surface, including a boiler body and a flue gas mechanism, and also includes a vertical flue gas channel 8 disposed inside the boiler body. One end of the vertical flue gas channel 8 is connected to the furnace 6 disposed inside the boiler body, and the other end is connected to the flag-type heating surface and its channel 9 disposed inside the boiler body. The flag-type heating surface and its channel 9 are connected to the flue gas mechanism.

[0021] Furthermore, the vertical flue gas channel 8 is also provided with a slag-forming tube bundle 7 between it and the furnace chamber 6.

[0022] Furthermore, a flue gas transfer chamber 10 is provided at the end of the vertical flue gas channel 8 away from the furnace 6, and the high-temperature flue gas in the furnace 6 is cooled down by the flue gas transfer chamber 10 and then transferred to the flag-shaped heating surface and its channel 9.

[0023] Further, the smoke exhaust mechanism comprises a boiler flue gas outlet 11 communicated with the flag type heating surface and its passage, and the boiler flue gas outlet 11 is communicated with a high-low temperature economizer 12 arranged outside the boiler body through a communicating pipeline.

[0024] Further, one end of the high-low temperature economizer 12 far from the boiler flue gas outlet 11 is communicated through a communicating pipeline.

[0025] Further, the boiler body comprises a boiler drum 1, a biomass hopper 4, a chain grate 5, a furnace 6;

[0026] The boiler drum 1 is arranged at the upper portion of the front end of the boiler body.

[0027] The biomass hopper 4 is arranged at the middle lower portion of the front end of the boiler body, and the upper portion of the biomass hopper 4 is communicated with a feeding port arranged on the boiler body, and the lower portion of the biomass hopper 4 is matched with the chain grate 5 arranged at the lower end of the boiler body.

[0028] Further, the outside of the boiler body is provided with a platform steel frame 3 and a platform staircase 2.

[0029] Further, the chain grate 5 is provided with a grate air chamber at the bottom of both sides.

[0030] Further, the chain grate 5 is provided with a slagging machine at the bottom.

[0031] In the above embodiment, the biomass particles fall into the front end of the chain grate 5 from the biomass hopper 4, and are uniformly burned by the grate, and are changed into ash and slag after burning in the furnace 6 and fall into the slagging machine for discharging. The biomass hopper is provided with an independent variable speed motor to drive the roller biomass hopper 4 to rotate, and the biomass particles are sent to the chain grate 5, and the rotation speed of the biomass hopper 4 can be adjusted according to the load size, so as to control the thickness of the material layer.

[0032] The air sent by the air blower is preheated by the air preheater 13, enters the furnace through the air ducts on both sides of the base of the chain grate 5, enters the furnace in the partitioned grate air chamber, and the flue gas after the fuel is burned and the excess air enter the membrane wall furnace 6, the slag condensing pipe bundle 7, the vertical membrane wall flue gas passage 8, the smoke turning chamber 10, the flag type heating surface and its passage 9, the boiler flue gas outlet 11, the high-low temperature economizer, the air preheater 12, the environmental protection equipment, and then enter the chimney to be discharged into the atmosphere.

[0033] The innovation of the present application mainly lies in that the vertical membrane wall flue gas passage and the smoke turning chamber are added between the membrane wall hearth and the flag type heating surface and its passage. The high temperature flue gas enters the vertical membrane wall flue gas passage 8 from the slag condensing pipe bundle 7 of the hearth 6, is further fully burnt and is cooled to below 700 DEG C, which is far below the ash melting point, so that the coking and blocking of the flag type heating surface pipe and the whole flue gas passage are avoided, thereby greatly prolonging the operation cycle of the boiler. After the flue gas enters the smoke turning chamber 10, the smoke speed is reduced and is turned upward to enter the flag type heating surface and its passage 9. Due to the inertial separation effect, part of the large particle dust is separated, and the abrasion and ash accumulation of the flag type heating surface pipe bundle are reduced.

[0034] The above specific embodiments further specifically describe the purpose, technical scheme and beneficial effects of the present application, and it should be understood that the above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can make equivalent replacement or change according to the technical scheme and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

[0035] In addition, in the description of the present application, it should be understood that the terms indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0036] Furthermore, in the present application, unless otherwise specifically defined and limited, the terms "mounting", "connection", "connecting", "fixing" and the like should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integral; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

Claims

1. A biomass boiler for preventing coking on flag-type heating surfaces, comprising a boiler body and a flue gas exhaust mechanism, characterized in that, It also includes a vertical flue gas passage set inside the boiler body, and one end of the vertical flue gas passage (8) is connected to the furnace (6) set inside the boiler body, and the other end is connected to the flag-type heating surface and its passage (9) set inside the boiler body. The flag-type heating surface and its passage (9) are connected to the exhaust mechanism. The vertical flue gas passage (8) is also provided with a slag condensation tube bundle (7) between the furnace (6); The vertical flue gas channel (8) is provided with a flue gas transfer chamber (10) at one end away from the furnace (6). The vertical flue gas channel (8) transfers the high-temperature flue gas in the furnace (6) to the flag-type heating surface and its channel (9) after cooling through the flue gas transfer chamber (10).

2. A biomass boiler for preventing coking on the flag-type heating surface according to claim 1, characterized in that, The flue gas exhaust mechanism includes a boiler flue gas outlet (11) that is connected to the flag-shaped heating surface and its channel. The boiler flue gas outlet (11) is connected to a high and low temperature economizer (12) located on the outside of the boiler body through a connecting pipe.

3. A biomass boiler for preventing coking on the flag-type heating surface according to claim 2, characterized in that, The high and low temperature economizer (12) is connected to the end of the boiler flue gas outlet (11) via a connecting pipe.

4. A biomass boiler for preventing coking on the flag-type heating surface according to claim 1, characterized in that, The boiler body includes a boiler drum (1), a feeder (4), a chain grate (5), and a furnace (6); The boiler drum (1) is located at the upper part of the front end of the boiler body; The feeder (4) is located in the lower part of the front end of the boiler body, and the upper part of the feeder (4) is connected to the feeding port located on the boiler body, and the lower part of the feeder (4) is connected to the chain grate (5) located at the lower end of the boiler body.

5. A biomass boiler for preventing coking on the flag-type heating surface according to claim 1, characterized in that, The boiler body is provided with a platform steel frame (3) and a platform ladder (2) on the outside.

6. A biomass boiler for preventing coking on the flag-type heating surface according to claim 4, characterized in that, The chain grate (5) has grate air chambers on both sides of its bottom.

7. A biomass boiler for preventing coking on the flag-type heating surface according to claim 4, characterized in that, The bottom of the chain grate (5) is equipped with a slag discharge machine.

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