Straw bundling direct-fired boiler with ultrasonic automatic descaling function

Abstract

The utility model discloses a bundled straw direct-fired boiler with an ultrasonic automatic descaling function, relates to the technical field of boilers, and solves the problem that a heat exchanger continuously precipitates in the heat exchange process to form a sediment heat-resistant layer. The utility model relates to an ultrasonic descaling boiler, which solves the problems that the total heat resistance of a whole heat exchanger is increased, the heat exchange coefficient and the working efficiency of the equipment are rapidly reduced and the energy consumption is increased due to the fact that a heat insulation layer reduces the performance and the heat exchange efficiency of the equipment in the prior art, and comprises a boiler main body, a plurality of rows of water cooling wall tubes and an ultrasonic descaling device, ultrasonic descaling devices are installed on the side wall of the boiler barrel and the side wall of the combustion chamber, the ultrasonic descaling devices are used for conducting ultrasonic descaling on the multiple rows of water cooling wall pipes located in the boiler barrel and on the side wall of the inner side of the combustion chamber, metal, scale and water vibrate along with ultrasonic vibration, due to different frequency responses among the metal, the scale and the water, asynchronous vibration is generated, and the scale is removed from the water cooling wall pipes. And the combination between the scale and the metal is destroyed, so that the scale layer is fatigued and loosened.

Description

Technical Field

[0001] This utility model relates to the technical field of boilers, and in particular to a direct-fired boiler for baled straw with ultrasonic automatic descaling function. Background Technology

[0002] Boilers and heat exchangers, as primary heat exchange components, are widely used in numerous industries, including petroleum, power, petrochemical, chemical, heating, and central air conditioning. Due to temperature and flow velocity differences in the liquid flowing inside the heat exchanger tubes, impurities such as salts, dust, silt, and microorganisms dissolved in the water continuously concentrate due to losses from circulation evaporation and airflow, increasing their proportion in the water. These impurities precipitate out during the heat exchange process, forming a deposited heat-insulating layer. This heat-insulating layer reduces the equipment's performance and heat exchange efficiency, leading to an increase in the overall thermal resistance of the heat exchanger. This causes a rapid decline in the heat transfer coefficient and operating efficiency, increasing energy consumption. In severe cases, it can cause blockages in some pipes, reduced unit operating load, and significant losses.

[0003] Most closed-loop water coolers use plate heat exchangers and circulating water for heat exchange. When the hardness of the circulating water exceeds 10 mg N / L, the calcium and magnesium bicarbonates in the water decompose into calcium carbonate and magnesium carbonate precipitates upon heating. These precipitates adhere to the heat-receiving surfaces of the heat exchanger, where they experience high heat intensity, forming hard or soft scale. After the circulating water dissipates heat through the cooling tower, the oxygen solubility in the water increases, causing oxygen corrosion of the pipes. Rust enters the heat exchanger with the circulating water and combines with the scale on the heat exchanger plates to form chocolate-colored scale flakes. This reduces the flow cross-section of the heat exchanger, gradually decreasing the heat transfer coefficient and operating efficiency, ultimately forcing the heat exchange equipment to be disassembled and descaled.

[0004] According to globally recognized data, a 1mm cumulative heat-insulating layer inside heat exchanger pipes will increase energy consumption by 33% and reduce condensation efficiency by more than 50%. It is conceivable that traditional periodic (usually 1-2 times a year) manual chemical descaling will cause the heat exchanger to operate under high load for a long time, which not only wastes energy and reduces COP and production efficiency, but also shortens the service life of the equipment. This is something that traditional treatment methods cannot avoid. Utility Model Content

[0005] To address the issue of heat exchangers continuously depositing and forming a heat-insulating layer during the heat exchange process, which reduces equipment performance and heat exchange efficiency, increases the overall thermal resistance of the heat exchanger, rapidly decreases the heat transfer coefficient and operating efficiency, and increases energy consumption, this invention aims to provide a baled straw direct-fired boiler with ultrasonic automatic descaling function.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] A direct-fired boiler for baled straw with ultrasonic automatic descaling function includes: a boiler body 1, water-cooled wall tubes 109, an ultrasonic descaling device 115, and a tail heat exchanger 116. The boiler body 1 has a combustion chamber 11 and a heat exchange chamber 12 inside. The heat exchange chamber 12 is located above the combustion chamber 11 and is connected to the combustion chamber 11. The front side wall of the combustion chamber 11 has a feed inlet 104, the side wall of the heat exchange chamber 12 has a flue gas outlet 105, and the bottom of the combustion chamber 11 has a slag outlet 103. The flue gas outlet 105 is connected to the tail flue of the boiler, and the tail heat exchanger 116 is installed on the tail flue of the boiler.

[0008] The top of the heat exchange chamber 12 is provided with a boiler drum 108, and the front side of the heat exchange chamber 12 is provided with a combustion chamber 110; multiple water-cooled wall pipes 109 are evenly distributed inside the boiler drum 108 and the inner side wall of the combustion chamber 11; the rear side wall of the combustion chamber 11 is provided with a water inlet 111 communicating with the water-cooled wall pipes 109; and the heat exchange chamber 12 is provided with a drain outlet and / or exhaust outlet communicating with the water-cooled wall pipes 109.

[0009] Ultrasonic descaling devices 115 are installed on the side walls of the boiler drum 108, combustion chamber 11, and tail heat exchanger 116. The installation locations are detailed in the attached diagram of the instruction manual. Figure 1 and Figure 3 As shown, ultrasonic descaling is performed on the boiler body, water-cooled walls, pipelines, heat exchangers, etc., specifically including the deposited soot on the outer wall of the water-cooled wall tube 109, the deposited water scale on the inner wall of the water-cooled wall tube 109, and soot and water scale in other locations.

[0010] The aforementioned multi-stroke combustion-powered baled straw biomass direct-fired boiler further includes: an in-furnace transmission system 3 and a first chain grate 4. The first chain grate 4 is installed at the bottom of the combustion chamber 11, and the in-furnace transmission system 3 is installed inside the combustion chamber 11 and above the first chain grate 4. The in-furnace transmission system 3 includes: at least one row of material conveying mechanisms, with multiple rows of material conveying mechanisms arranged sequentially from top to bottom. The front end of the uppermost material conveying mechanism is located below the feed inlet 104. The in-furnace transmission system 3 is used to repeatedly transfer biomass fuel and transfer the biomass fuel to the chain grate 4. The first chain grate 4 is used to transfer the fully burned biomass fuel located above it to the ash outlet 103.

[0011] The aforementioned multi-pass combustion biomass direct-fired boiler for baled straw further includes: a second chain grate 113; a feeding hopper 114 is provided on the front side wall of the combustion chamber 11, the feeding hopper 114 is located below the feed inlet 104; the first chain grate 4 is located near the rear side wall of the combustion chamber 11; the second chain grate 113 is located near the front side wall of the combustion chamber 11; and the ash discharge port is located between the first chain grate 4 and the second chain grate 113.

[0012] The above-mentioned multi-stroke combustion-powered baled straw biomass direct-fired boiler includes an in-furnace transmission system 3 comprising: at least one row of material conveying mechanisms, with multiple rows of material conveying mechanisms arranged sequentially from top to bottom; the front end of the uppermost material conveying mechanism is located near the front side wall of the combustion chamber 11 and below the feed inlet 104; for any row of material conveying mechanisms, when its front or rear end is located near the side wall of the combustion chamber 11, its other end is spaced from the side wall of the combustion chamber 11, and the distance between the other end and the side wall of the combustion chamber 11 is greater than the maximum size of the biomass fuel.

[0013] In the aforementioned multi-stroke combustion-powered direct-fired boiler for baled straw biomass, any two adjacent rows of material conveying mechanisms are arranged such that the front end of one row is located near the front side wall of the combustion chamber 11, while the rear end of the other row is located near the rear side wall of the combustion chamber 11. Each row of material conveying mechanisms includes multiple drive shafts located in the same plane and arranged parallel to each other. The two ends of each drive shaft are rotatably connected to the left and right side walls of the combustion chamber 11, respectively. The multiple drive shafts rotate synchronously in a clockwise or counterclockwise direction, and the rotation direction of the multiple drive shafts is the same as the direction of transfer of biomass fuel above them.

[0014] The aforementioned multi-stroke combustion-powered direct-fired boiler for baled straw biomass further includes: a baling shaft 5 and a coke-breaking shaft 106. The two ends of the baling shaft 5 are rotatably connected to the left and right side walls of the combustion chamber 11, respectively. The two ends of the coke-breaking shaft 106 are rotatably connected to the left and right side walls of the combustion chamber 11, respectively. Both the baling shaft 5 and the coke-breaking shaft 106 are located above the first chain grate 4. The baling shaft 5 and the coke-breaking shaft 106 rotate synchronously in a clockwise or counterclockwise direction. The rotation direction of the baling shaft 5 and the coke-breaking shaft 106 is opposite to the conveying direction of the first chain grate 4.

[0015] The aforementioned multi-stroke combustion biomass direct-fired boiler also includes: a baling straw feeder 2, which is used to transfer biomass fuel to the feed inlet 104 of the boiler body 1 and push it into the combustion chamber 11; the baling straw feeder 2 includes: a structural frame 21, baffles 22 and a hopper 23, the rear end of the structural frame 21 is connected to the feed inlet 104 of the boiler body 1, baffles 22 are installed on the left and right sides of the structural frame 21, and the hopper 23 travels on the upper surface of the structural frame 21, and the hopper 23 is used to push the biomass fuel located on the structural frame 21 into the combustion chamber 11;

[0016] The bottom of the hopper 23 is equipped with wheels, and gears are rotatably mounted on the side of the hopper 23. A rack is provided on the upper surface of the structural frame 21. The gears mesh with the racks, and the hopper 23 moves on the structural frame 21 by driving the gears to rotate.

[0017] The aforementioned multi-stroke combustion-powered direct-fired boiler for baled straw biomass further includes: a speed reducer unit 6, which is used to drive the furnace transmission system 3, the first chain grate 4, the second chain grate 113, the baling shaft 5, and the coke breaking shaft 106.

[0018] The above-mentioned multi-pass combustion-powered direct-fired boiler for baled straw biomass includes a preheating arch 101 inclined at the top front side of the combustion chamber 11, a limiting arch 102 inclined at the top rear side of the combustion chamber 11, and a burnout arch 107 inclined at the bottom of the combustion chamber 11. The preheating arch 101 is located above the feed inlet 104, and the burnout arch 107 is located above the ash outlet. Air ducts 112 are provided on the left and right side walls of the combustion chamber 11.

[0019] Because this utility model employs the aforementioned technology, it has the following positive effects compared to existing technologies:

[0020] (1) In this utility model, ultrasonic descaling devices 115 are installed on the side walls of the boiler drum and the combustion chamber. The ultrasonic descaling devices 115 are used to perform ultrasonic descaling on the multi-row cold wall pipes located inside the boiler drum and on the inner side wall of the combustion chamber. When the ultrasonic waves act on the liquid, many tiny bubbles are formed in the liquid, forming a "cavitation effect". The bursting of the bubbles will generate a shock wave with extremely high energy, which will destroy the adsorption between the deposits and the metal. The scale will then form sand-like particles, and some of them will fall off from the surface of the pipe wall. Water seeps into the heated surface through tiny cracks under capillary action, where water is evaporated, thereby causing the carbonized deposits to expand and fall off in pieces, achieving the purpose of descaling. The ultrasonic vibration causes the metal, scale and water to vibrate. Due to the different frequency responses of the three, asynchronous vibration is generated, forming a relative shear force at the interface between the scale layer and the pipe wall, i.e., the "shear effect", which destroys the bond between the scale and the metal, causing the scale layer to fatigue and loosen. It features a technology that prevents argon corrosion, inhibits scale formation, and thoroughly removes scale, resulting in significant effects. It also boasts high-efficiency heat exchange, sterilization, and environmental protection, saving energy. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a direct-fired boiler for baled straw with ultrasonic automatic descaling function according to this utility model.

[0022] Figure 2 This is a cross-sectional view of a baled straw direct-fired boiler with ultrasonic automatic descaling function according to this utility model.

[0023] Figure 3 This is a side view of the main body of a direct-fired boiler for baled straw with ultrasonic automatic descaling function according to this utility model.

[0024] Figure 4 This is an axonometric view of the main body of a direct-fired boiler for baled straw with ultrasonic automatic descaling function according to this utility model.

[0025] Figure 5 This is a schematic diagram of the structure of a direct-fired boiler for baled straw with ultrasonic automatic descaling function, which adopts an indirect coupling combustion method.

[0026] Figure 6 This is a cross-sectional view of a direct-fired boiler for baled straw with ultrasonic automatic descaling function, which adopts an indirect coupling combustion method.

[0027] Figure 7 This is a side view of the main body of a direct-fired boiler for baled straw with ultrasonic automatic descaling function, which adopts an indirect coupling combustion method.

[0028] Figure 8 This is an axonometric view of the main body of a direct-fired boiler for baled straw with ultrasonic automatic descaling function, which adopts an indirect coupling co-firing method.

[0029] Figure 9 This is a schematic diagram showing the installation location of the tail heat exchanger.

[0030] Figure 10 This is a block diagram illustrating the interaction of ultrasound in a solid-liquid two-phase system.

[0031] In the attached diagram: 1. Boiler body; 2. Straw baling feeder; 3. Furnace transmission system; 4. First chain grate; 5. Bagged straw breaking shaft; 6. Reducer unit; 11. Combustion chamber; 12. Heat exchange chamber; 21. Structural frame; 22. Baffle; 23. Hopper; 101. Preheating furnace arch; 102. Limiting furnace arch; 103. Slag discharge port; 104. Feed inlet; 105. Smoke outlet; 106. Coke breaking shaft; 107. Burnout furnace arch; 108. Boiler drum; 109. Water-cooled wall tubes; 110. Burnout chamber; 111. Water inlet; 112. Air duct; 113. Second chain grate; 114. Feed hopper; 115. Ultrasonic descaling device; 116. Tail heat exchanger. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention.

[0033] Please refer to Figures 1 to 10The diagram shows a direct-fired boiler for baled straw with ultrasonic automatic descaling function. It includes: a boiler body 1, water-cooled wall tubes 109, an ultrasonic descaling device 115, and a tail heat exchanger 116. The boiler body 1 contains a combustion chamber 11 and a heat exchange chamber 12. The heat exchange chamber 12 is located above and connected to the combustion chamber 11. The front side wall of the combustion chamber 11 has a feed inlet 104, and the side wall of the heat exchange chamber 12 has a flue gas outlet 105. The bottom of the combustion chamber 11 has a slag outlet 103. The combustion chamber 11 is used for burning biomass fuel. The heat exchange chamber 12 is used for heat exchange and external energy supply. The flue gas outlet 105 is connected to the boiler tail flue, and the tail heat exchanger 116 is installed on the boiler tail flue.

[0034] The top of the heat exchange chamber 12 is provided with a boiler drum 108, and the front side of the heat exchange chamber 12 is provided with a combustion chamber 110; multiple water-cooled wall pipes 109 are evenly distributed inside the boiler drum 108 and the inner side wall of the combustion chamber 11; the rear side wall of the combustion chamber 11 is provided with a water inlet 111 communicating with the water-cooled wall pipes 109; and the heat exchange chamber 12 is provided with a drain outlet and / or exhaust outlet communicating with the water-cooled wall pipes 109.

[0035] An ultrasonic descaling device 115 is installed on the side wall of the boiler drum 108 and the combustion chamber 11. The ultrasonic descaling device 115 is used to perform ultrasonic descaling on the multi-drain cold wall pipes 109 located inside the boiler drum 108 and on the inner side wall of the combustion chamber 11.

[0036] Furthermore, in a preferred embodiment, it further includes: an in-furnace drive system 3 and a first chain grate 4. The first chain grate 4 is installed at the bottom of the combustion chamber 11, and the in-furnace drive system 3 is installed inside the combustion chamber 11 and above the first chain grate 4. The in-furnace drive system 3 includes: at least one row of material conveying mechanisms, and multiple rows of material conveying mechanisms are arranged sequentially from top to bottom. The front end of the uppermost material conveying mechanism is located below the feed inlet 104. The in-furnace drive system 3 is used to repeatedly transfer biomass fuel and transfer the biomass fuel to the chain grate 4. The first chain grate 4 is used to transfer the fully burned biomass fuel located above it to the slag outlet 103. By using multiple rows of material conveying mechanisms to transfer biomass fuel in multiple strokes, the travel distance and combustion time of biomass fuel in the combustion chamber 11 can be effectively increased, making the biomass fuel burn more completely.

[0037] Furthermore, in a preferred embodiment, it further includes: a second chain grate 113, a feeding hopper 114 provided on the front side wall of the combustion chamber 11, the feeding hopper 114 being located below the feed inlet 104, a first chain grate 4 being disposed near the rear side wall of the combustion chamber 11, a second chain grate 113 being disposed near the front side wall of the combustion chamber 11, a slag discharge port being located between the first chain grate 4 and the second chain grate 113, and the feeding hopper 114 being located below the feed inlet 104. The high-temperature flue gas generated during the combustion of biomass fuel on the second chain grate 113 can dry and preheat the biomass fuel entering through the feed inlet 104.

[0038] Furthermore, in a preferred embodiment, the in-furnace transmission system 3 includes: at least one row of material conveying mechanisms, with multiple rows of material conveying mechanisms arranged sequentially from top to bottom; the front end of the uppermost material conveying mechanism is located near the front side wall of the combustion chamber 11 and below the feed inlet 104; for any row of material conveying mechanisms, when its front or rear end is located near the side wall of the combustion chamber 11, its other end is spaced from the side wall of the combustion chamber 11, and the distance is larger than the maximum size of the biomass fuel, so as to facilitate the conveying of biomass fuel from front to back or from back to front by the row of material conveying mechanisms. After the material reaches the end, the biomass fuel falls onto the next row of material conveying mechanisms located on the lower layer. Specifically, after the biomass fuel enters through the feed port 104, it falls to the front end of the uppermost material conveying mechanism. The uppermost material conveying mechanism moves the biomass fuel backward until it falls to the rear end of the second layer material conveying mechanism. Then, the second layer material conveying mechanism moves it forward until it falls to the front end of the third layer material conveying mechanism... until the biomass fuel falls onto the first chain grate 4. Then, the first chain grate 4 moves the fully burned biomass fuel to the slag discharge port 103.

[0039] Furthermore, in a preferred embodiment, for any two adjacent rows of material conveying mechanisms, if the front end of one row of material conveying mechanisms is located near the front side wall of the combustion chamber 11, then the rear end of the other row of material conveying mechanisms is located near the rear side wall of the combustion chamber 11. Each row of material conveying mechanisms includes: multiple drive shafts, which are located in the same plane and arranged parallel to each other. The two ends of each drive shaft are rotatably connected to the left and right side walls of the combustion chamber 11, respectively. The multiple drive shafts rotate synchronously in a clockwise or counterclockwise direction. The rotation direction of the multiple drive shafts is the same as the transfer direction of the biomass fuel located above them. The synchronous rotation of the multiple drive shafts in the same row realizes the transfer of biomass fuel until it falls onto the next layer of material conveying mechanism.

[0040] Furthermore, in a preferred embodiment, the end of any material conveying mechanism near the side wall of the combustion chamber 11 is higher than the end away from the side wall of the combustion chamber 11.

[0041] Furthermore, in a preferred embodiment, it further includes: a packing-breaking shaft 5 and a coke-breaking shaft 106. The two ends of the packing-breaking shaft 5 are rotatably connected to the left and right side walls of the combustion chamber 11, respectively. The two ends of the coke-breaking shaft 106 are also rotatably connected to the left and right side walls of the combustion chamber 11, respectively. Both the packing-breaking shaft 5 and the coke-breaking shaft 106 are located above the first chain grate 4. The packing-breaking shaft 5 and the coke-breaking shaft 106 rotate synchronously in a clockwise or counterclockwise direction. The rotation direction of the packing-breaking shaft 5 and the coke-breaking shaft 106 is the same as the conveying direction of the first chain grate 4, that is, the rotation direction of the packing-breaking shaft 5 and the coke-breaking shaft 106 is the same as the conveying direction of the first chain grate 4. The drive and driven wheels of the chain grate 4 rotate in the same direction. Specifically, the first chain grate 4 moves biomass fuel counterclockwise, and its upper surface moves biomass fuel from back to front. The baling shaft 5 and the coke crushing shaft 106 rotate counterclockwise. When the biomass fuel passes the baling shaft 5 or the coke crushing shaft 106, the teeth on the baling shaft 5 or the coke crushing shaft 106 are lifted upward. The baling shaft 5 can spread the irregularly burned straw bales evenly. The coke crushing shaft 106 can break the excessively large slag blocks formed after the straw bales are burned into slag blocks that meet the discharge standards of the slag discharge machine.

[0042] Furthermore, in a preferred embodiment, it further includes: a baling straw feeder 2, which is used to transfer biomass fuel to the feed inlet 104 of the boiler body 1 and push it into the combustion chamber 11; the baling straw feeder 2 includes: a structural frame 21, baffles 22 and a hopper 23, the rear end of the structural frame 21 is connected to the feed inlet 104 of the boiler body 1, baffles 22 are installed on the left and right sides of the structural frame 21, the hopper 23 travels on the upper surface of the structural frame 21, and the hopper 23 is used to push the biomass fuel located on the structural frame 21 into the combustion chamber 11;

[0043] The bottom of the hopper 23 is equipped with wheels, and gears are rotatably mounted on the side of the hopper 23. The upper surface of the structural frame 21 is equipped with a rack, and the gears mesh with the rack. The hopper 23 moves on the structural frame 21 by driving the gears to rotate.

[0044] Furthermore, in a preferred embodiment, it further includes: a speed reducer 6, which is used to drive the furnace transmission system 3, the first chain grate 4, the second chain grate 113, the packing breaker shaft 5, and the coke breaker shaft 106.

[0045] Furthermore, in a preferred embodiment, the combustion chamber 11 is provided with an inclined preheating furnace arch 101 at the top front side, an inclined limiting furnace arch 102 at the top rear side, and an inclined burnout furnace arch 107 at the bottom of the combustion chamber 11. The preheating furnace arch 101 is located above the feed inlet 104; the burnout furnace arch 107 is located above the slag outlet; and air ducts 112 are provided on the left and right side walls of the combustion chamber 11.

[0046] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention.

[0047] Based on the above, this utility model also has the following embodiments:

[0048] In a further embodiment of this utility model, such as Figures 1 to 4 The diagram shows a biomass direct-fired boiler with a single-row material conveying mechanism in the furnace transmission system 3. This embodiment is based on a baled straw biomass direct-fired boiler with a single-row material conveying mechanism.

[0049] In a further embodiment of this utility model, the baling straw feeder 2 uses a reciprocating mechanical transmission to perform work. The gear of the hopper 23 is driven by a motor or by an external chain drive to realize the reciprocating movement of the hopper 23 on the structural frame 21. The baling straw feeder 2 pushes the baled straw in the hopper into the feed inlet 104 at the front end of the boiler combustion chamber. After the feeding is completed, the hopper 23 returns to the starting point according to the original stroke. After new baled straw is put in, the previous operation is repeated.

[0050] In a further embodiment of this utility model, the transmission system consists of a motor and a reducer as the power source. A chain drives the transmission shaft to rotate, generating torsional force. This torsional force drives the gears on both sides of the equipment to rotate. The gears mesh with the rack and pinion, moving in a directional manner along the track established by the rack and pinion. The directional wheel set and gears form a triangular structure, ensuring stable movement of the equipment during directional movement and preventing derailment or self-spinning. The transmission system components are connected to the feeding hopper, and the operation of the components drives the feeding hopper to achieve the purpose of feeding materials.

[0051] In a further embodiment of this utility model, a closed door is provided between the boiler body 1 and the baled straw feeder 2. When the feeding hopper transports the baled straw to the feed inlet 104 of the boiler body 1, the closed door closes and the boiler door opens at the same time to prevent the high-temperature air inside the boiler from mixing with the low-temperature air outside, which would cause the furnace temperature to drop and affect the boiler's thermal efficiency. The closed door can prevent backfire at the boiler feed inlet 104 and solve safety hazards. The closed structure is reasonably equipped with maintenance and cleaning channels to facilitate the boiler operator to maintain and repair the components of each part of the baled straw feeder.

[0052] In a further embodiment of this utility model, the boiler body 1, as the core equipment for burning straw baled fuel, is composed of three sections: boiler, furnace, and grate. The boiler body 1 adopts a longitudinally arranged horizontal fire tube structure, wherein the three-dimensional height of the combustion zone of the furnace body is increased, such as... Figures 1 to 4 As shown, a biomass direct-fired boiler with a row of material conveying mechanisms forms two combustion layers by adding a drive shaft. At the same time, there is a gap between the drive shafts, which allows the straw baled fuel to be fully oxygenated during combustion. This structure can promote the complete combustion of straw.

[0053] In a further embodiment of this utility model, the pot body adopts a longitudinally arranged flue pipe outer pot cylinder 108, with a header below the pot cylinder 108 and water-cooled wall pipes 109 on the side of the pot cylinder 108. The headers are arranged in a structure connected by tube bundles. The furnace body is composed of components such as furnace door, feed inlet, front wall of upper fire port, furnace arch, upper combustion zone drive shaft assembly, water-cooled wall pipes 109, headers, and header connecting pipes. The chain grate 4 is placed below the furnace body, and the grate surface and the furnace body form the lower combustion zone, i.e., the combustion chamber 11. The straw burnout is discharged into the slag remover through the grate slag outlet 103.

[0054] In a further embodiment of this utility model, multiple air ducts 112 are distributed between multiple rows of drive shafts in the furnace transmission system 3, above and on both sides of the chain grate 4.

[0055] In a further embodiment of this utility model, a biomass direct-fired boiler with multiple material conveying mechanisms and multiple round trips is adopted. The boiler body is designed as a multi-round-trip flue gas structure. The superheated flue gas exchanges heat with components such as water-cooled walls, flue pipes, flue box, boiler drum, header and connecting pipe bundle through the boiler body structure. A cast-in-place wall is added to the lower side of the boiler drum to realize a two-way flue gas path for superheated flue gas, increasing the heat exchange area between the flue gas and the boiler body, thereby reducing the exhaust gas temperature.

[0056] In a further embodiment of this utility model, after the straw baled fuel enters the boiler through the feed inlet, the furnace door is closed by a motor. The furnace door and the feed inlet are connected to the boiler body by a flexible connecting pipe bundle and a connecting pipe bundle, and water is supplied. The heat released by the straw baled fuel entering the boiler and starting to burn can be exchanged between the furnace door and the feed inlet.

[0057] In a further embodiment of this invention, the baled straw fuel enters the upper combustion zone through the furnace door to begin preheating and combustion, and then moves at a constant speed towards the rear of the combustion chamber via a drive shaft structure. The drive shaft is arranged in a stepped, horizontal configuration towards the rear of the boiler to form a grate structure. The length of the drive shaft is greater than the width of the boiler. Sealed water boxes are installed at both ends of the shaft extending outside the furnace, and water pipes are connected to them. The shaft rotation is powered by an electric motor and a reducer. This power is converted into torque through a sprocket assembly and gears, driving the shaft to rotate in a directional and constant-speed manner. This design solves the problem of baled straw fuel stacking and compressing into a furnace arch during combustion in the upper combustion zone due to lack of stroke power, completely eliminating the risk of boiler component damage and smoke escaping from the furnace due to poor ventilation.

[0058] In a further embodiment of this invention, after the baled straw fuel travels from the upper combustion zone to the end of the upper combustion chamber, the unburned baled straw fuel falls into the lower combustion chamber. The lower combustion chamber is driven by the chain grate 4 to move the unburned baled straw fuel at a constant speed towards the ash outlet 103. During this movement, the bale-breaking shaft 5 works to evenly spread the unburned baled straw fuel for continued combustion, while the coke-breaking shaft 106 works to break and disperse the remaining coke residue into ash blocks that meet the ash discharge requirements and are discharged from the boiler. The rotation direction of the baled straw shaft 5 and the coke-breaking shaft 106 is the same as that of the drive wheel / driven wheel of the chain grate 4. The surfaces of the baled straw shaft 5 and the coke-breaking shaft 106 inside the furnace are fitted with teeth of varying lengths by welding. The rotation of the baled straw shaft 5 and the coke-breaking shaft 106 drives the teeth to do work to achieve the design requirements. The work of the baled straw shaft 5 can evenly spread the straw baled fuel that has been burned into an irregular shape. This design makes it easy for the straw baled fuel with a moisture content that exceeds the standard and is not easy to burn out to come into contact with sufficient oxygen and absorb the heat of the furnace to quickly dry and gasify for combustion. The work of the coke-breaking shaft 106 can break the slag blocks that are too large after the straw baled fuel is burned out into slag blocks that meet the discharge standards of the slag discharge machine. This design facilitates slag discharge and reduces the failure rate of the slag removal equipment.

[0059] In a further embodiment of this utility model, such as Figures 5 to 8 The diagram shows a biomass direct-fired boiler with a single-row material conveying mechanism and a double-grate structure designed for the furnace transmission system 3. This embodiment is based on a baled straw biomass direct-fired boiler with a single-row material conveying mechanism and a double-grate structure.

[0060] In a further embodiment of this utility model, two sets of grates are designed to be combined into a grate assembly with their tails facing each other to work together. The grate assembly is placed below the boiler body 1, wherein the second chain grate 113 is used to burn biomass briquettes; and the first chain grate 4 is used to burn straw baled fuel. The two sets of grates face each other at their tails and share a single slag discharge machine.

[0061] In a further embodiment of this utility model, the second chain grate 113 is located on the front side and is equipped with a biomass briquette fuel feeder. The feeder is located below the baled straw feeder 2 and feeds fuel into the feeding hopper 114 via a conveyor belt mechanism. The overall size of the second chain grate 113 is smaller than that of the first chain grate 4. A furnace arch is set on the top of the second chain grate 113, and masonry covering is provided on both sides and the front wall to form an independent combustion chamber. No water-cooled walls or connecting tube bundles are installed around the combustion chamber for heat exchange. The area directly above the structure of the second chain grate 113 is between the boiler feed inlet and the upper fire outlet. The first chain grate 4 is located behind the second chain grate 113 and its overall size is larger than that of the second chain grate 113.

[0062] In a further embodiment of this utility model, during operation, the second chain grate 113 does not have water-cooled walls and connecting tube bundles installed in its chamber structure. Therefore, the superheated flue gas generated by fuel combustion does not undergo heat exchange in its combustion chamber, but instead directly enters the corresponding upper combustion chamber through the upper fire port at the front end of the furnace arch.

[0063] In a further embodiment of this invention, according to the principle of energy conservation, when straw baled fuel with excessive moisture content enters the boiler for combustion, it does not first release heat, but rather absorbs heat to evaporate moisture and dry itself. Only after drying to the point where it can self-ignite can it burn and release heat. Throughout this process, the temperature inside the boiler will inevitably decrease because the straw with excessive moisture content absorbs heat and dries itself. In practice, this phenomenon will be particularly pronounced when using straw baled fuel with a moisture content of around 60%, severely affecting heat conversion efficiency. Because the entire heat absorption process is continuous, it is easy for the proportion of heat released by straw combustion to be lower than the heat absorbed by the straw with excessive moisture content during self-drying, resulting in the boiler continuously consuming straw but failing to produce heat. Meanwhile, as the boiler combustion chamber temperature continues to decrease, it cannot meet the requirement that the moisture released during the drying process of the straw with excessive moisture content be vaporized and participate in combustion. As the moisture is conducted through the boiler and discharged into the atmosphere along with the flue gas, it continues to absorb heat. When passing through components such as flue pipes, ductwork, dust collectors, and induced draft fans, it adheres to these components, causing corrosion, damaging related equipment, accelerating aging, and reducing service life. When excessive moisture enters the chimney, it immediately turns into water mist, adheres to the inner wall of the chimney, forms condensate, and flows downwards to the base of the chimney, continuing to corrode the chimney and creating serious safety hazards.

[0064] In a further embodiment of this utility model, as described above, the core purpose of adding a new combustion system to the original boiler structure is to solve the hidden danger caused by insufficient heat replenishment in the boiler combustion chamber when excessive heat is absorbed during the burning of straw with excessive moisture content.

[0065] In a further embodiment of this invention, the superheated flue gas released during the combustion of biomass briquettes by the second chain grate 113 and its corresponding combustion chamber directly enters the combustion chamber where the straw baled fuel is used for work without heat exchange, thus solving the aforementioned problem. This replenishes the heat consumed in the combustion chamber where the straw baled fuel is used for work. By continuously adjusting the consumption of biomass briquettes, the temperature in the combustion chamber where the straw baled fuel is used for work is maintained within the required temperature range. This not only dries the straw baled fuel with excessive moisture but also ensures the gasification requirements after water vapor evaporation. This ensures that the consumed fuel is not wasted, turning the moisture in the straw baled fuel into valuable energy through complete heat conversion.

[0066] In a further embodiment of this utility model, the ultrasonic descaling device has the following technical features: the descaling device mainly prevents the large-area formation of scale in heat exchange equipment, ensuring the continuous and uninterrupted operation of the heat exchange equipment. It has outstanding technical features such as descaling, scale prevention, corrosion prevention, improved heat exchange efficiency, sterilization and algae removal, environmental protection and energy saving.

[0067] In a further embodiment of this utility model, the descaling mechanism is as follows: When ultrasonic waves act on a liquid, many tiny bubbles are formed within the liquid, creating a "cavitation effect." The bursting of these bubbles generates high-energy shock waves, disrupting the adsorption between the deposits and the metal. The scale then forms gravel-like particles, some of which detach from the pipe wall surface. Water seeps into the heated surface through tiny cracks under capillary action, where it evaporates, causing the carbonized deposits to expand and detach in sheets, thus achieving descaling. Ultrasonic vibration causes the metal, scale, and water to vibrate. Due to the different frequency responses among the three, asynchronous vibrations occur, creating a relative shear force at the interface between the scale layer and the pipe wall, i.e., a "shear effect." This breaks the bond between the scale and the metal, leading to fatigue and loosening of the scale layer. This technology features significant effects in preventing argon corrosion, inhibiting scale formation, and thoroughly removing scale. It is highly efficient, heat-exchanges, sterilizes, disinfects, and is environmentally friendly and energy-saving.

[0068] In a further embodiment of this invention, the scale inhibition mechanism is as follows: Ultrasonic waves in the liquid medium break down water molecules into H radicals and HO radicals, and even H+ and OH, through the "cavitation effect." OH and scale-forming ions can form compounds such as Ca(OH)2 and Mg(OH)2, thereby increasing the water's ability to dissolve scale-forming ions and thus enhancing its scale-dissolving capacity, exhibiting an "activation" effect. The ultrasonic radiation also produces a "superionic condensation" phenomenon, preventing scale-forming ions from adhering to the metal. Vibration on the scale surface generates high-speed microflows and a "cavitation effect" between the metal and water, disrupting the conditions for scale formation and deposition on the pipe wall, thus hindering the sedimentation of these gravel-like substances on the pipe wall. Uncrystallized scale and scale that is difficult to dissolve after crystallization in the water form a suspended state, flowing away with the medium or being discharged through sewage.

[0069] In a further embodiment of this invention, to prevent oxidation corrosion, dissolved oxygen in the water is forced out of the naturally formed cracks on the inner surface of the pipe wall under the action of ultrasonic vibration. The pulse vibration of the ultrasonic waves acts on the inner wall surface of the pipe for a long time, causing deformation near the tiny gaps. These deformations seal the edges of the cracks, preventing dissolved oxygen in the water from seeping into the cracks, eliminating the source of corrosion, and protecting the metal from abrasion.

[0070] In a further embodiment of this invention, the system operates online, using physical methods to prevent scaling, resulting in no pollution to water bodies and the environment, and no corrosion to pipelines and containers. Compared to other methods that address scaling after it has formed, this descaling method is more environmentally friendly, while the heat exchange equipment operates at its optimal working condition for an extended period, resulting in significant overall energy savings.

[0071] In a further embodiment of this utility model, the descaling device is a next-generation product for condenser descaling. It is environmentally friendly, requires no chemical additives, does not require shutdown, and can inhibit and remove scale during operation, extending the unit's lifespan, improving heat exchange efficiency, and demonstrating long-term and significant cost-effectiveness.

[0072] In a further embodiment of this utility model, ultrasound refers to sound waves with a frequency higher than 20kHz. When it propagates in coal, it produces a series of mechanical, thermal, and chemical effects. Ultrasonic descaling is mainly achieved through mechanical action, cavitation action, and thermal action.

[0073] In a further embodiment of this invention, the ultrasonic descaling device 115 is installed on the side wall of the steam drum, which is only 6mm thick, much smaller than the wavelength of ultrasonic waves. Therefore, the ultrasonic energy is transferred to the water through this location, resulting in the strongest penetration and the best energy conversion effect. For this reason, the ultrasonic generator should preferably be installed perpendicular to the thinnest metal wall surface. There should be no reinforcing components such as stiffeners, connecting pipes, or tube sheets near the generator to minimize energy loss.

[0074] In a further embodiment of this utility model, the ultrasonic descaling device 115 is connected to the control panel via signal. By setting the start time or start frequency of the ultrasonic descaling device 115 on the control panel, the function of automatic descaling of the water-cooled wall tube 109 by ultrasonic waves can be realized.

[0075] In a further embodiment of this utility model, the flue gas outlet 105 is connected to the boiler tail flue, and the tail heat exchanger 116 is installed on the boiler tail flue. The tail heat exchanger 116 adopts an economizer structure. An economizer is a device installed at the lower part of the boiler tail flue to recover the waste heat of the exhaust gas. Its function is to heat the boiler feedwater to a saturated water surface under the pressure of the steam drum. The economizer is a heat exchange device, usually using a bare tube structure or a finned structure, composed of multiple parallel serpentine tubes. Its working principle mainly utilizes the high-temperature flue gas at the boiler tail to exchange heat with the feedwater. When the high-temperature flue gas flows through the economizer's flue, heat is transferred to the feedwater inside the tube through the pipe wall. The feedwater continuously flows in the economizer, absorbing heat from the flue gas, and its temperature gradually increases. After releasing heat, the flue gas temperature decreases, thereby achieving the purpose of reducing the exhaust gas temperature and reducing exhaust heat loss. From the perspective of heat transfer methods, it is mainly through heat conduction and convection. Heat conduction refers to the transfer of heat from one part of a hot object to another, or from one hot object to a colder object in contact with it. In an economizer, the heat from the flue gas is conducted to the feedwater inside the pipes through the metallic material of the pipe walls. Convective heat transfer, on the other hand, is the transfer of heat caused by the macroscopic movement of fluids. In an economizer, the flow of flue gas and feedwater facilitates the transfer of heat between them.

[0076] In a further embodiment of this utility model, the economizer functions in two ways: First, it reduces flue gas temperature, improves boiler efficiency, and saves fuel. By recovering waste heat from the flue gas to heat the feedwater, it reduces the amount of heat required to vaporize the water within the boiler, thereby improving energy utilization efficiency. Second, the increased feedwater temperature before entering the steam drum reduces the temperature difference between the drum walls, lowers thermal stress, and extends the service life of the steam drum.

[0077] In a further embodiment of this invention, during boiler startup, the economizer also serves to prevent water from vaporizing in a stagnant state. A pipe is connected from the central drain pipe of the steam drum to the inlet of the economizer, acting as a recirculation pipe to keep the water in the economizer flowing and prevent vaporization.

[0078] In a further embodiment of this utility model, the installation position of the ultrasonic descaling device 115 is as follows: Figure 1 and Figure 3 As shown, the ultrasonic descaling device 115 consists of a pulse power supply, a transducer, and a sealing assembly. The transducer can be an H-80-GW high-temperature type transducer, which is used for descaling boiler bodies, metallurgical blast furnaces, or other special high-temperature parts. The transducer has a Curie temperature of 960℃ and a maximum operating temperature of 380℃. It is used in conjunction with a specially designed lead wire protection cooling device.

[0079] In a further embodiment of this utility model, the ultrasonic descaling device 115 of this utility model can operate in a high-temperature environment. The selected model is based on the authorized invention patent CN201110325280.X a condenser online ultrasonic cyclone descaling device, CN201620666724.4 plate heat exchanger descaling equipment, and commercially available models from Harbin Tianbao Ink Technology Development Co., Ltd.

[0080] The above are merely preferred embodiments of the present utility model and are not intended to limit the implementation methods and protection scope of the present utility model. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A direct-fired boiler for baled straw with ultrasonic automatic descaling function, characterized in that, include: The boiler body (1), water-cooled wall tubes (109), ultrasonic descaling device (115), and tail heat exchanger (116) are provided inside the boiler body (1). The boiler body (1) is provided with a combustion chamber (11) and a heat exchange chamber (12). The heat exchange chamber (12) is located on the upper side of the combustion chamber (11) and is connected to the combustion chamber (11). The front side wall of the combustion chamber (11) is provided with a feed inlet (104), the side wall of the heat exchange chamber (12) is provided with a flue gas outlet (105), and the bottom of the combustion chamber (11) is provided with a slag outlet (103). The flue gas outlet (105) is connected to the tail flue of the boiler, and the tail heat exchanger (116) is installed on the tail flue of the boiler. The top of the heat exchange chamber (12) is provided with a boiler drum (108), and the front side of the heat exchange chamber (12) is provided with a combustion chamber (110); multiple water cooling wall pipes (109) are evenly distributed inside the boiler drum (108) and the inner side wall of the combustion chamber (11), and the rear side wall of the combustion chamber (11) is provided with a water inlet (111) communicating with the water cooling wall pipes (109), and the heat exchange chamber (12) is provided with a drain outlet and / or exhaust outlet communicating with the water cooling wall pipes (109); Ultrasonic descaling devices (115) are installed on the side walls of the boiler drum (108), combustion chamber (11) and tail heat exchanger (116).

2. The baled straw direct-fired boiler with ultrasonic automatic descaling function according to claim 1, characterized in that, Also includes: The furnace transmission system (3) and the first chain grate (4) are installed at the bottom of the combustion chamber (11). The furnace transmission system (3) is installed in the combustion chamber (11) and above the first chain grate (4). The furnace transmission system (3) includes: at least one row of material conveying mechanism, and multiple rows of material conveying mechanism are arranged from top to bottom. The front end of the material conveying mechanism at the top layer is located below the feed inlet (104). The furnace transmission system (3) is used to repeatedly transfer biomass fuel and transfer biomass fuel to the chain grate (4). The first chain grate (4) is used to transfer the biomass fuel located above it and which has been fully burned to the slag outlet (103).

3. The baled straw direct-fired boiler with ultrasonic automatic descaling function according to claim 2, characterized in that, It also includes: a second chain grate (113), a feeding hopper (114) provided on the front side wall of the combustion chamber (11), the feeding hopper (114) being located below the feed inlet (104), the first chain grate (4) being located near the rear side wall of the combustion chamber (11), the second chain grate (113) being located near the front side wall of the combustion chamber (11), and the slag outlet being located between the first chain grate (4) and the second chain grate (113).

4. The baled straw direct-fired boiler with ultrasonic automatic descaling function according to claim 2 or claim 3, characterized in that, The in-furnace transmission system (3) includes: at least one row of material conveying mechanisms, and multiple rows of material conveying mechanisms arranged sequentially from top to bottom; the front end of the material conveying mechanism located at the top layer is set close to the front side wall of the combustion chamber (11) and located below the feed inlet (104); for any row of material conveying mechanisms, when its front end or rear end is set close to the side wall of the combustion chamber (11), its other end is provided with a gap from the side wall of the combustion chamber (11), and the gap size is greater than the maximum size of biomass fuel.

5. The baled straw direct-fired boiler with ultrasonic automatic descaling function according to claim 4, characterized in that, For any two adjacent rows of material conveying mechanisms, if the front end of one row of material conveying mechanisms is located close to the front side wall of the combustion chamber (11), then the rear end of the other row of material conveying mechanisms is located close to the rear side wall of the combustion chamber (11).

6. The baled straw direct-fired boiler with ultrasonic automatic descaling function according to claim 5, characterized in that, Any row of material conveying mechanisms includes: multiple drive shafts, which are located in the same plane and are arranged in parallel to each other. The two ends of each drive shaft are rotatably connected to the left and right side walls of the combustion chamber (11), respectively. The multiple drive shafts rotate synchronously in a clockwise or counterclockwise direction, and the rotation direction of the multiple drive shafts is the same as the transfer direction of the biomass fuel located above them.

7. The baled straw direct-fired boiler with ultrasonic automatic descaling function according to claim 2, characterized in that, Also includes: The two ends of the packing breaker (5) and the coke breaker (106) are rotatably connected to the left and right side walls of the combustion chamber (11), respectively. The two ends of the coke breaker (106) are rotatably connected to the left and right side walls of the combustion chamber (11), respectively. The packing breaker (5) and the coke breaker (106) are both located above the first chain grate (4). The packing breaker (5) and the coke breaker (106) rotate synchronously in a clockwise or counterclockwise direction. The rotation direction of the packing breaker (5) and the coke breaker (106) is opposite to the conveying direction of the first chain grate (4).

8. The baled straw direct-fired boiler with ultrasonic automatic descaling function according to claim 2, characterized in that, Also includes: A baling straw feeder (2) is used to transfer biomass fuel to the feed inlet (104) of the boiler body (1) and push it into the combustion chamber (11); the baling straw feeder (2) includes: a structural frame (21), a baffle (22) and a hopper (23). The rear end of the structural frame (21) is connected to the feed inlet (104) of the boiler body (1). Baffles (22) are installed on the left and right sides of the structural frame (21). The hopper (23) travels on the upper surface of the structural frame (21). The hopper (23) is used to push the biomass fuel located on the structural frame (21) into the combustion chamber (11); The bottom of the hopper (23) is equipped with wheels, and gears are rotatably mounted on the side of the hopper (23). The upper surface of the structural frame (21) is equipped with a rack, and the gear meshes with the rack. The hopper (23) moves on the structural frame (21) by driving the gear to rotate.

9. The baled straw direct-fired boiler with ultrasonic automatic descaling function according to claim 3, characterized in that, Also includes: The speed reducer unit (6) is used to drive the furnace transmission system (3), the first chain grate (4), the second chain grate (113), the packing shaft (5), and the coke breaking shaft (106).

10. The baled straw direct-fired boiler with ultrasonic automatic descaling function according to claim 1, characterized in that, The combustion chamber (11) has an inclined preheating furnace arch (101) at the top front side, an inclined limiting furnace arch (102) at the top rear side, and an inclined burnout furnace arch (107) at the bottom. The preheating furnace arch (101) is located above the feed inlet (104); the burnout furnace arch (107) is located above the slag outlet; and air ducts (112) are provided on the left and right side walls of the combustion chamber (11).

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