Biomass hot air stove

Abstract

The present invention discloses a biomass hot air stove, which comprises: a combustion chamber, the upper part of which is determined by a front arch, a rear arch, and a first part of the combustion chamber top located between the front arch and the rear arch, and a wall panel, wherein a given distance is left between the upper end of the rear arch and the combustion chamber top, and the part of the combustion chamber top located at the rear side of the upper end of the rear arch is the second part, so that a reflux cavity is constructed between the combustion chamber top and the rear arch; a heat exchanger is installed in the reflux cavity; a feeding device is located at the front side of the combustion chamber, and introduces biomass fuel into the combustion chamber from a furnace port arranged at the front side of the combustion chamber; and a purification air outlet device is connected to the end of the reflux cavity. Based on the present invention, the service life of the combustion chamber can be effectively improved without reducing the heat utilization rate.

Description

Technical Field

[0001] The invention relates to a biomass hot blast stove. Background Art

[0002] Biomass hot air furnace is a new type of hot air furnace that uses biomass fuel as fuel. Common biomass fuels include straw, sawdust, bagasse, rice bran and other organic matter formed through photosynthesis. Generally, biomass hot air furnaces do not directly use straw as fuel. Biomass fuel is actually processed products of straw, etc., and its physical form is granular.

[0003] The top of the combustion chamber of the existing biomass hot blast furnace is generally welded with a flat plate. During the upward process of high-temperature flue gas, the heating of various parts of the combustion chamber is uneven, and the top of the combustion chamber is relatively fully heated. Based on the principle of thermal expansion and contraction, the uneven heating of various parts of the combustion chamber will inevitably lead to different degrees of thermal expansion and contraction, thus generating large thermal stress, which may cause damage to the top of the combustion chamber. The top stress concentration, coupled with the effect of thermal expansion and contraction, can easily cause damage to the top of the combustion chamber.

[0004] In addition, in order to enhance the heat utilization rate, the existing biomass hot air furnace is usually equipped with multiple combustion chambers connected in sequence, and each combustion chamber is divided into two parts, the upper and lower parts, which are connected by a fire pipe, and the lower part of the combustion chamber is usually provided with an ash removal port. Although the existence of the fire pipe increases the heat exchange area between the high-temperature flue gas and the wind flow, making the heat utilization rate higher, once the fire pipe is blocked, the ash accumulated in the upper part of the combustion chamber will not be cleaned. If ash cleaning is required, the combustion chamber must be cut open, which will bring great inconvenience to the ash cleaning work. If the ash cleaning is not timely, it will also lead to the occurrence of gas explosion.

[0005] Accordingly, each combustion chamber of a traditional biomass hot blast furnace is connected by a bridge. As the only channel for high-temperature flue gas to flow between the combustion chambers, the bridge is not only prone to stress concentration but also severely corroded by the flue gas and is easily damaged. Once the bridge is damaged, the entire equipment will be unusable. Summary of the invention

[0006] The object of the present invention is to provide a biomass hot blast stove which can effectively increase the service life of a combustion chamber without reducing the heat utilization rate.

[0007] In an embodiment of the present invention, a biomass hot air stove is provided, comprising:

[0008] A combustion chamber, the upper part of which is defined by a front arch, a rear arch, a first portion of a combustion chamber top located between the front arch and the rear arch, and a wall panel, wherein a given distance is left between the upper end of the rear arch and the combustion chamber top, and a portion of the combustion chamber top located behind the upper end of the rear arch is the second portion, so that a reflow chamber is constructed between the combustion chamber top and the rear arch;

[0009] A heat exchanger is installed in the reflux chamber;

[0010] A feeding device is located at the front side of the combustion chamber and introduces biomass fuel into the combustion chamber from a furnace port arranged at the front side of the combustion chamber;

[0011] The purified air outlet device is connected to the end of the reflux chamber.

[0012] Optionally, the heat exchanger is a shell and tube heat exchanger;

[0013] Correspondingly, the flue gas generated by the combustion chamber flows through the shell side of the shell and tube heat exchanger, and the cold fluid used to cool the flue gas flows through the tube side.

[0014] Optionally, the pipelines constituting the pipe pass are arranged in multiple layers in the upper and lower directions of the reflux chamber;

[0015] There is a gap between the pipes on each floor for smoke flow.

[0016] Optionally, the feeding device is installed on the front side of the front wall panel of the biomass hot air stove, and the feeding device includes:

[0017] A feed hopper, the lower part of which is provided with a front guide plate and a rear guide plate, and a discharge port is formed between the front and rear guide plates;

[0018] An impeller is installed at the discharge port and feeds the material based on the gap between the blades of the impeller.

[0019] Optionally, the impeller is a straight-blade impeller;

[0020] There are four blades, which are evenly distributed around the impeller shaft;

[0021] Correspondingly, the angle between the front guide plate and the rear guide plate is 90 degrees.

[0022] Optionally, a slide is provided below the impeller, the front end of the slide being higher than the rear end, and being used for guiding the materials into the furnace opening.

[0023] Optionally, the grate plates arranged at the lower part of the combustion chamber gradually descend from front to back.

[0024] The biomass hot air stove according to claim 7, characterized in that the grate plate comprises:

[0025] still film;

[0026] The moving piece is located at the lower side of the static piece and is used to adjust the flow gap of the grate;

[0027] The adjusting mechanism is used to drive the moving plate to move in the front-rear direction.

[0028] Optionally, the lower middle portion of the rear arch is tilted rearward;

[0029] An air outlet pipe is provided at the rear side of the rear arch, and the air outlet pipe receives the reflux cavity and is connected to the purification air outlet device.

[0030] Optionally, the air purification device includes:

[0031] A desulfurization and denitrification agent hopper connected to the air outlet pipe through a bypass;

[0032] The cyclone dust collector is connected to the air outlet pipe and is used for settling ash in the flue gas.

[0033] It should be noted that the combustion of biomass fuel in a biomass hot blast furnace is the thermal utilization of biomass. In the embodiment of the present invention, a heat exchanger is set at the top of the furnace, that is, the top of the combustion chamber. The existence of the heat exchanger effectively cools the flue gas, thereby reducing the impact of the flue gas temperature on the top of the combustion chamber. Specifically, the temperature of the flue gas in direct contact with the top of the combustion chamber is reduced, which reduces the thermal stress generated by the burner top, thereby effectively improving the service life of the combustion chamber. At the same time, the heat exchanger can be used as a heat source for other applications. While cooling the flue gas, it does not reduce the thermal utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the main cross-sectional structure of a biomass hot air furnace in one embodiment.

[0035] Figure 2 Schematic diagram of the top view of the biomass hot air furnace in one embodiment.

[0036] Figure 3 It is a schematic diagram of the left side structure of a biomass hot air furnace in one embodiment.

[0037] In the figure: 1. blower, 2. air hole, 3. grate, 4. furnace mouth, 5. slide, 6. straight blades, 7. impeller, 8. feed hopper, 9. front guide plate, 10. rear guide plate, 11. front temperature-resistant layer, 12. front arch, 13. reflux chamber, 14. heat exchanger, 15. temperature-resistant layer, 16. rear arch, 17. air outlet pipe, 18. desulfurization and denitrification agent hopper, 19. dust collector, 20. exhaust port, 21. cone, 22. ash box, 23. base, 24. furnace door. DETAILED DESCRIPTION

[0038] It should be noted that the hot blast furnace includes a shell installed on a base 23, and the shell needs to be insulated, that is, an insulation layer, such as an asbestos layer, needs to be provided inside the shell.

[0039] Generally speaking, in this field, the feed port is Figure 1The side where the middle furnace opening 4 is located is the front side, and the side opposite to it is the rear side. The left and right sides are further determined. In addition, the front view is essentially determined according to the reference system selected during design, rather than the conventional front and back.

[0040] Figure 1 The biomass hot air furnace shown in the figure has a basic structure including a combustion chamber, a heat exchanger 14, a feeding device, and a purification air outlet device. And as a general configuration, it also includes conventional auxiliary structures such as a furnace door 24.

[0041] In the embodiment of the present invention, the biomass hot air furnace adopts a relatively typical rectangular furnace body, and accordingly, the shell has a front wall panel, a rear wall panel, and left and right wall panels. It should be noted that, in order to simplify the description, in the embodiment of the present invention, the front wall panel is used to represent the front wall panel of the shell and the corresponding insulation structure, which does not affect the correct understanding of those skilled in the art.

[0042] In an embodiment of the present invention, a single combustion chamber structure is adopted. In addition to the wall panels, the basic structure of the combustion chamber also includes auxiliary structures arranged on the inner side of the wall panels, such as the front arch 12 and the rear arch 16. These auxiliary structures are used to construct the structure of the upper part of the combustion chamber to better guide the smoke.

[0043] from Figure 1 It can be seen from the structure shown that the combustion chamber top is divided into two parts, front and rear, by the upper part of the rear arch 16. The front part is called the first part, and the rear part is called the second part. The smoke enters the second part from the first part and then goes down.

[0044] It should be noted that the direction of flue gas is based on heat convection on the one hand and induced draft on the other hand. Figure 1 The dust collector 19 shown in FIG. 1 is generally equipped with an induced draft fan to induce air, so that Figure 1 Suction is generated in the air outlet pipe 17 shown in the figure, which belongs to the active exhaust method.

[0045] If it is simply based on heat convection or the siphon effect generated thereby, it is known that resistance will be generated during dust removal, affecting the drainage. In the embodiment of the present invention, an active drainage method is preferred, that is, an induced draft fan is used, such as Figure 1 Active exhaust is achieved by means of the exhaust vent 20 shown in FIG.

[0046] Furthermore, the upper portion of the combustion chamber is defined by the front arch 12, the rear arch 16, and the first portion of the combustion chamber top and the wall panel located between the front arch 12 and the rear arch 16. Since a given distance is left between the upper end of the rear arch 16 and the combustion chamber top, at this time, the upper portion of the combustion chamber is not blocked by the rear arch 16 in the front-to-rear direction, and the smoke is discharged rearwardly therefrom.

[0047] The portion of the combustion chamber top located at the rear side of the upper end of the rear arch 16 is referred to as the second portion, so that a reflow cavity 13 is constructed between the combustion chamber top and the rear arch 16, and the smoke is discharged backward through the reflow cavity 13.

[0048] Furthermore, regarding the heat exchanger 14, it is installed in the reflux chamber 13. After the high-temperature flue gas is cooled by the heat exchanger 14, the heat acting on the top of the combustion chamber becomes relatively mild, and it is not easy to generate large thermal stress. When the design can meet higher thermal stress conditions and faces relatively small thermal stress, it is not easy to cause damage to the top of the combustion chamber, thereby making the combustion chamber have a longer service life.

[0049] At the same time, the heat exchanger 14 can be used as a component of heat utilization, and no loss is generated due to the cooling of the flue gas. For example, the biomass hot air furnace is used for heating. Figure 1 The heat exchanger 14 shown in the figure is a primary heat exchanger, and the biomass hot air furnace uses a secondary heat exchanger to supply heat to the outside. The two-stage heat exchanger can be incorporated into the heating network without causing heat loss.

[0050] As a basic configuration, Figure 1 The combustion chamber is also provided with a feeding device, which is located at the front side of the combustion chamber and introduces biomass fuel into the combustion chamber from a furnace port 4 arranged at the front side of the combustion chamber.

[0051] The purified air outlet device is connected to the end of the reflux chamber 13 and supplies heat to the target heat-using equipment after purification.

[0052] The heat exchanger 14 may be a plate heat exchanger, a liner heat exchanger, a shell and tube heat exchanger, or a coil heat exchanger, with shell and tube heat exchangers and coil heat exchangers being preferred, as both provide a larger heat exchange area with relatively little impact on fluid flow.

[0053] If a shell and tube heat exchanger is used, the flue gas generated by the combustion chamber flows through the shell side of the shell and tube heat exchanger, and the cold fluid used to cool the flue gas flows through the tube side. Figure 1 As can be seen from the structure shown, there are multiple rows and columns of circular holes in the reflux chamber 13, which are used to represent the tube body. The part covering the tube body is recorded as the reflux chamber shell. Correspondingly, it can be equivalent to a shell and tube heat exchanger with one shell side and several tube sides, and the overall heat exchange effect is relatively good.

[0054] Further preferably, since the flue gas flow rate is relatively fast, in order to improve the heat exchange efficiency, the pipes of the tube pass are arranged in multiple layers in the upper and lower directions of the reflux chamber; accordingly, a flue gas flow gap is left between each layer of pipes, so that the flue gas can be cooled step by step as it ascends and moves laterally, thereby achieving a better heat exchange effect.

[0055] Correspondingly, there are gaps between the pipe layers to meet the requirements of smoke flow in the reflow chamber 13 .

[0056] For the feeding device, the speed at which the material enters the combustion chamber will affect the stability of the biomass combustion due to the state of the material. Therefore, in a preferred embodiment, the feeding device is installed on the front side of the front wall plate of the biomass hot blast furnace, and the feeding device includes:

[0057] The feed hopper 8 has a front guide plate 9 and a rear guide plate 10 at its lower portion, and a discharge port is formed between the front and rear guide plates. Figure 1 In the figure, the front guide plate 9 is tilted backward and downward, and the rear guide plate 10 is tilted backward and forward, and cooperates with the wall panel or the independently set left and right side panels to enclose the discharge port. For the guide plate, the rear guide plate 10 can be omitted, and the discharge port can be directly constructed by the front wall panel.

[0058] The arrangement of the front and rear guide plates mentioned above will gradually collect the materials in a top-down direction and narrow to a minimum at the discharge port.

[0059] An impeller 7 is provided and installed at the discharge port. The material is fed based on the gap between the blades of the impeller 7. In other words, when the impeller 7 stops rotating, the material stops flowing. When the impeller speed increases, the material flow rate increases, thereby controlling the feeding speed.

[0060] It should be noted that biomass fuel is generally in the form of particles, which are actually rod-like particles and have low fluidity. The mutual support between the particles ensures that even when the impeller 7 is in a stopped state and the discharge port is not tightly closed, the material will not flow downward uncontrollably.

[0061] Based on the aforementioned feeding method of the impeller 7, it can be known that by feeding with the help of the gap between the blades, the distance between the blades and the structure that determines the discharge port will not be too large. Based on the material properties of the biomass fuel, when the impeller 7 stops, the mutual support between the particles prevents the material from leaking uncontrollably.

[0062] exist Figure 1 In the structure shown, the impeller 7 is a straight-blade impeller;

[0063] There are four blades, which are evenly distributed around the impeller shaft;

[0064] Correspondingly, the angle between the front guide plate 9 and the rear guide plate 10 is 90 degrees. In this case, there will inevitably be a state where the front guide plate 9 is coplanar with a blade, and a state where the rear guide plate 10 is coplanar with a blade, and the closure is the tightest at this time. The state where the distance between the blade and the discharge port is the largest is when a blade is exactly located in the middle of the discharge port. At this time, the gaps between the two blades and the structure that determines the discharge port are not large in the horizontal and vertical directions. Based on the supporting effect of the material, the material will not go down.

[0065] In the aforementioned structure, the feed hopper 8 is located at the front side of the combustion chamber. In order to introduce the material into the combustion chamber in a more orderly manner, a slide 5 is provided below the impeller 7. Accordingly, the slide 5 has a high front end and a low rear end, and is used to introduce the material into the furnace mouth 4.

[0066] For hot blast furnaces, there are grates inside the furnace. On the one hand, the space under the grate is used to introduce air, and on the other hand, the slag produced by combustion will also fall through the gap of the grate. Figure 2 The furnace door 24 shown in the figure is used to take out the slag regularly.

[0067] Affected by the feeding method, the grate plate 3 arranged at the lower part of the combustion chamber gradually decreases from front to back. The biomass fuel has a granular physical property and has a certain fluidity, but the fluidity is slightly poor. The inclined grate is conducive to the material flowing backward.

[0068] As mentioned above, one of the purposes of the grate plate 3 is to introduce air. The amount of introduced air will affect the sufficiency of material combustion. For this purpose, the grate plate 3 includes:

[0069] still film;

[0070] The moving piece is located on the lower side of the static piece and is used to adjust the flow gap of the grate. If the gap between the grate bars contained in the moving piece and the static piece is the same and the grate bars of the two pieces overlap in the inclination direction, the flow gap is the largest. As the misalignment increases, the flow gap gradually decreases.

[0071] An adjustment mechanism is provided to drive the moving piece to move in the front-to-back direction, specifically, along the tilting direction of the grate piece 3. It should be noted that the so-called front-to-back movement does not affect the understanding of those skilled in the art, and the tilting direction of the grate piece 3 also belongs to the macroscopic front-to-back direction.

[0072] In addition, regarding the adjustment mechanism, the output motion form is linear motion, which is the most common motion form in the mechanical field. However, in order to achieve precise adjustment, the adjustment mechanism adopts a nut-and-screw mechanism.

[0073] In order to reduce the impact of the rear arch 16 on the combustion chamber space, the lower middle portion of the rear arch 16 is tilted backwards to ensure that the combustion chamber space is less affected. The rear arch 16 tilted backwards has less impact on, for example, the layout of the air outlet duct 17. In particular, when the air outlet duct 17 adopts active exhaust, its layout has better flexibility and is less affected by the space of the rear arch 16.

[0074] Correspondingly, an air outlet pipe 17 is provided at the rear side of the rear arch 16 , and the air outlet pipe 17 receives the reflux chamber 13 and is connected to the purification air outlet device, or in other words, the air outlet pipe 17 is used for the connection between the reflux chamber 13 and the purification air outlet device.

[0075] Furthermore, the air purification device comprises:

[0076] The desulfurization and denitrification agent hopper 18 is connected to the air outlet pipe 17 through a bypass, and is used to deliver the purifying agent into the air outlet pipe 17 .

[0077] Figure 1 The dust collector 19 shown in the figure is included in the purification air outlet device. The dust collector 19 shown in the figure is a composite dust collector, which itself constitutes a bag dust collector. At the same time, a cyclone dust collector can be configured in its front stage to remove coarser ash, while the bag dust collector can be used to remove relatively fine ash.

Claims

1. A biomass hot air stove, characterized in that: include: A combustion chamber, the upper part of which is defined by a front arch, a rear arch, a first portion of a combustion chamber top located between the front arch and the rear arch, and a wall panel, wherein a given distance is left between the upper end of the rear arch and the combustion chamber top, and a portion of the combustion chamber top located behind the upper end of the rear arch is the second portion, so that a reflow chamber is constructed between the combustion chamber top and the rear arch; A heat exchanger is installed in the reflux chamber; A feeding device is located at the front side of the combustion chamber and introduces biomass fuel into the combustion chamber from a furnace port arranged at the front side of the combustion chamber; The purified air outlet device is connected to the end of the reflux chamber; The heat exchanger is a shell and tube heat exchanger; Accordingly, the flue gas generated in the combustion chamber flows through the shell side of the shell and tube heat exchanger, and the cold fluid used to cool the flue gas flows through the tube side; The pipeline of the pipe-pass is arranged in multiple layers in the upper and lower directions of the reflux chamber; There is a gap between the pipes on each floor for smoke flow; The grate plates arranged at the lower part of the combustion chamber gradually lower from front to back; The grate includes: still film; The moving piece is located at the lower side of the static piece and is used to adjust the flow gap of the grate; The adjusting mechanism is used to drive the moving plate to move in the front-rear direction.

2. The biomass hot air stove according to claim 1, characterized in that: The feeding device is installed on the front side of the front wall plate of the biomass hot air furnace, and the feeding device includes: A feed hopper, the lower part of which is provided with a front guide plate and a rear guide plate, and a discharge port is formed between the front and rear guide plates; An impeller is installed at the discharge port and feeds the material based on the gap between the blades of the impeller.

3. The biomass hot air stove according to claim 2, characterized in that: The impeller is a straight blade impeller; There are four blades, which are evenly distributed around the impeller shaft; Correspondingly, the angle between the front guide plate and the rear guide plate is 90 degrees.

4. The biomass hot air stove according to claim 2, characterized in that: A slide is provided below the impeller, the front end of the slide being higher than the rear end, and is used to guide the materials into the furnace mouth.

5. The biomass hot air stove according to claim 1, characterized in that: The lower middle part of the rear arch slopes backwards; An air outlet pipe is provided at the rear side of the rear arch, and the air outlet pipe receives the reflux cavity and is connected to the purification air outlet device.

6. The biomass hot air stove according to claim 5, characterized in that: The air purification device comprises: A desulfurization and denitrification agent hopper connected to the air outlet pipe through a bypass; The cyclone dust collector is connected to the air outlet pipe and is used for settling ash in the flue gas.

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