Multi-fuel nine-return-stroke efficient energy-saving boiler

Abstract

The multi-fuel nine-return-stroke efficient energy-saving boiler comprises a water jacket shell, a hearth, a graded air supply assembly and a heat exchange assembly, the water jacket shell is of a closed water cavity structure defined by an outer-layer heat preservation shell and an inner-layer boiler wall, the top of the water jacket shell is of an arc-shaped structure and is provided with an air outlet, the hearth is arranged in the water jacket shell, and the graded air supply assembly is arranged in the hearth. The bottom of the hearth is provided with a fire grate and a furnace door, a lower ash cleaning opening is formed below the fire grate and used for cleaning ash in a fire grate area, the graded air supply assembly comprises a primary air channel, a secondary air channel and a tertiary air channel, the primary air channel is correspondingly arranged below the fire grate, and the secondary air channel is correspondingly arranged below the tertiary air channel. The secondary air channel and the tertiary air channel are symmetrically arranged on the side wall of the hearth, the heat exchange assembly comprises a preheating pipe horizontally arranged over the hearth and a plurality of annular fire pipes arranged over the preheating pipe, and the annular fire pipes are arranged in a multi-layer staggered mode in the smoke flowing direction.

Description

Technical Field

[0001] This invention relates to the field of boiler technology, specifically to a multi-fuel, nine-pass, high-efficiency, energy-saving boiler. Background Technology

[0002] Boilers, as thermal energy devices that transfer the heat energy released from fuel combustion to a medium such as water to produce hot water or steam, are widely used in industrial production, heating, and domestic hot water supply. The structure of a traditional boiler typically includes a furnace and a single flue or simple fire tube assembly located above the furnace. The high-temperature flue gas generated by the combustion of fuel in the furnace is discharged through the flue, exchanging heat with the water in the boiler's water chamber during this process.

[0003] However, existing boilers generally suffer from short flue gas flow paths and insufficient heat exchange in their design. Specifically, in most boilers, flue gas exits the chimney after only one or two passes, resulting in a significant amount of heat being lost into the atmosphere before being effectively absorbed. This hinders the improvement of boiler thermal efficiency and leads to energy waste. Furthermore, traditional single-pass or short-pass structures result in insufficient contact time between the flue gas and heat exchange components, limiting the heat exchange area and preventing the deep utilization of flue gas thermal energy. Therefore, how to extend the flue gas flow path and increase the number of heat exchange cycles within a limited space to improve boiler thermal efficiency is a pressing technical problem that needs to be solved in this field. Summary of the Invention

[0004] The purpose of this invention is to provide a multi-fuel nine-pass high-efficiency and energy-saving boiler to solve the problems of short flue gas flow and insufficient heat exchange leading to low thermal efficiency in conventional boilers.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A multi-fuel, nine-pass, high-efficiency, energy-saving boiler includes a water jacket shell, a furnace, a staged air supply assembly, and a heat exchange assembly. The water jacket shell is a closed water cavity structure formed by an outer insulation shell and an inner furnace wall. The top of the water jacket shell has an arc-shaped structure and an air outlet. The furnace is located inside the water jacket shell, and a grate and a furnace door are located at the bottom of the furnace. A lower ash cleaning port is provided below the grate for cleaning ash and slag in the grate area. The staged air supply assembly includes a primary air channel, a secondary air channel, and a tertiary air channel. The primary air channel is located below the grate, and the secondary and tertiary air channels are symmetrically arranged in the furnace. The heat exchange assembly includes a preheating tube horizontally arranged above the furnace and multiple annular fire tubes located above the preheating tubes. The multiple annular fire tubes are arranged in multiple staggered layers along the flue gas flow direction, so that the flue gas rises from the furnace and flows back and forth between adjacent annular fire tubes in sequence, forming nine continuous flue gas heat exchange cycles. During the flow of the nine cycles, the flue gas contacts the outer wall of the preheating tube, the outer wall of the annular fire tube, and the inner furnace wall of the water jacket shell in sequence to achieve multi-stage heat exchange. The side wall of the water jacket shell is provided with an upper ash cleaning port corresponding to the installation area of ​​the annular fire tube for cleaning the ash adhering to the outer wall of the annular fire tube.

[0006] Preferably, a water level gauge for monitoring the liquid level in the water chamber is provided on the outer side of the water jacket housing.

[0007] Preferably, the nine flue gas heat exchange return paths are formed by an alternating arrangement of multiple layers of annular fire tubes. Each time the flue gas passes through a layer of annular fire tubes and completes a turnback, it corresponds to completing one heat exchange return path, thereby extending the contact time between the flue gas and the heat exchange components and the heat exchange path.

[0008] Preferably, the primary air duct, secondary air duct, and tertiary air duct are all connected to the same blower, and each air duct is independently equipped with an air volume regulating device. By adjusting the air volume of each air duct, the different combustion requirements of the three fuels, coal, firewood, and biomass pellets, can be adapted.

[0009] Preferably, the preheating pipe is fixedly arranged horizontally above the furnace, with its bottom facing directly into the furnace interior to directly absorb the radiant heat generated by fuel combustion in the furnace to achieve the first stage of heat exchange.

[0010] Preferably, the multiple annular fire tubes are arranged in a multi-layered, staggered manner along the vertical direction, with the arrangement positions of adjacent layers of annular fire tubes being staggered, so that the flue gas forms an S-shaped reciprocating flow between adjacent annular fire tubes, ensuring that the flue gas fully flows through the outer wall of each annular fire tube.

[0011] By adopting the above technical solution, the present invention has the following advantages compared with the prior art: This invention provides a multi-fuel, nine-pass, high-efficiency, energy-saving boiler. By setting up preheating tubes and multiple layers of staggered annular fire tubes, nine continuous flue gas heat exchange passes are constructed. The flue gas flows sequentially between the preheating tubes and multiple layers of annular fire tubes directly above the furnace, forming an S-shaped reciprocating flow. This extends the single-pass or short-pass flue gas path of traditional boilers into a nine-pass ultra-long path, significantly increasing the contact time and heat exchange area between the flue gas and the heat exchange components. It realizes multi-stage utilization of radiative and convective heat exchange, effectively solving the technical problem of low thermal efficiency caused by short flue gas flow and insufficient heat exchange in existing boilers, and significantly improving the boiler's thermal energy utilization rate. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of the present invention. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0014] It should be noted that in this invention, the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are all based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element of this invention must have a specific orientation, and therefore should not be construed as a limitation of this invention. Example

[0015] Please refer to Figure 1 As shown, this invention discloses a multi-fuel nine-pass high-efficiency energy-saving boiler, which mainly includes a water jacket shell 1, a furnace 2, a staged air supply assembly 3, and a heat exchange assembly 4. The water jacket shell 1 is formed by the outer insulation shell 11 and the inner furnace wall 12 together to form a closed water cavity structure 13. The water cavity is used to contain the heat exchange medium (such as water). The top of the water jacket shell 1 is designed as an arc structure, and an air outlet 14 is provided at its highest point to ensure that the steam or gas generated during boiler operation can be discharged smoothly and to prevent the gas pressure from affecting the heat exchange efficiency.

[0016] The furnace 2 is located inside the lower part of the water jacket shell 1 and serves as the main area for fuel combustion. A grate 21 and a furnace door 22 for adding fuel are installed at the bottom of the furnace 2. A lower ash removal port 23 is provided below the grate 21 for periodically cleaning the ash and slag falling in the grate 21 area to ensure smooth ventilation in the combustion area.

[0017] The staged air supply assembly 3 includes a primary air duct 31, a secondary air duct 32, and a tertiary air duct 33. The primary air duct 31 is located below the grate 21 and is used to provide basic oxygen for fuel combustion. The secondary air duct 32 and the tertiary air duct 33 are symmetrically arranged on the side wall of the furnace 2 and are used to supplement oxygen to the upper space of the furnace 2, forming a staged air supply, which effectively suppresses the generation of nitrogen oxides and promotes the complete combustion of unburned combustible gases.

[0018] The heat exchange assembly 4 includes a preheating pipe 41 horizontally arranged above the furnace 2, and multiple annular fire tubes 42 located above the preheating pipe 41. The preheating pipe 41 is fixedly arranged in the horizontal direction, with its bottom facing directly into the interior of the furnace 2, directly absorbing the intense radiant heat generated by fuel combustion in the furnace 2, thus achieving efficient heat exchange in the first stage.

[0019] Multiple annular fire tubes 42 are arranged in a multi-layered, staggered pattern along the vertical direction, meaning that the positions of adjacent layers of annular fire tubes are staggered, causing the flue gas to flow back and forth in an S-shape between adjacent annular fire tubes. Specifically, after rising from the furnace 2, the flue gas first passes through the area of ​​the preheating tube 41, and then flows back and forth sequentially between the multiple layers of annular fire tubes 42. Each time the flue gas passes through one layer of annular fire tubes and completes one directional reversal, it corresponds to completing one heat exchange cycle. Through the staggered arrangement of the multiple layers of annular fire tubes, this embodiment forms a total of nine continuous flue gas heat exchange cycles. During the flow of these nine cycles, the flue gas successively contacts the outer wall of the preheating tube 41, the outer wall of the annular fire tube 42, and the inner furnace wall 12 of the water jacket shell 1, achieving multi-stage and sufficient heat exchange, thereby maximizing the absorption of heat from the flue gas.

[0020] The side wall of the water jacket shell 1 is provided with an upper ash cleaning port 15 corresponding to the installation area of ​​the annular fire tube 42, which is used to periodically clean the ash adhering to the outer wall of the annular fire tube 42 to prevent the ash from affecting the heat transfer efficiency.

[0021] A water level gauge 16 is installed on the outside of the water jacket shell 1. The water level gauge 16 is connected to the water cavity 13 and is used to monitor the liquid level in the water cavity 13 in real time to ensure the water level safety during boiler operation and prevent dry burning accidents caused by water shortage.

[0022] The nine flue gas heat exchange cycles are specifically formed by the staggered arrangement of multiple layers of annular fire tubes 42. After the flue gas enters the heat exchange area from the top of the furnace 2, the flue gas is forced to continuously change its flow direction between the tube bundles due to the staggered positions of adjacent layers of annular fire tubes 42, forming a tortuous flow path. Each time the flue gas passes through one layer of annular fire tubes 42 and completes one turn, it is considered to have completed one heat exchange cycle. This process repeats, significantly improving the boiler's thermal efficiency by extending the contact time and heat exchange path between the flue gas and the heat exchange components.

[0023] The primary air duct 31, secondary air duct 32, and tertiary air duct 33 are all connected to the same blower (not shown in the figure) to simplify the airflow system. Each air duct is also independently equipped with an airflow regulating device (such as an air valve or damper). When switching between different fuels such as coal, firewood, or biomass pellets, the airflow in each air duct can be adjusted to precisely control the air distribution ratio in different areas of the furnace, adapting to the combustion characteristics of different fuels and ensuring that the boiler achieves efficient and clean combustion when burning multiple fuels.

[0024] The preheating tube 41 is fixedly arranged horizontally above the furnace 2, with its bottom surface unobstructed, directly facing the high-temperature flames and flue gas inside the furnace 2. The water medium inside the preheating tube 41 can directly absorb the intense radiant heat generated by fuel combustion in the furnace 2, achieving the first stage of heat exchange. This arrangement makes full use of the furnace's radiant heat, further improving the overall thermal efficiency of the boiler.

[0025] Multiple annular fire tubes 42 are arranged in a multi-layered, staggered pattern along the vertical direction. Specifically, the positions of adjacent layers of annular fire tubes are staggered in the horizontal projection, causing the flue gas to flow back and forth in an S-shape between adjacent annular fire tubes during its ascent. This arrangement effectively breaks the laminar flow state of the flue gas, increases the degree of flue gas turbulence, ensures that the flue gas can fully flow through the outer wall of each annular fire tube 42, avoids flue gas short-circuiting, and achieves uniform and efficient heat exchange.

[0026] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A multi-fuel, nine-pass, high-efficiency, energy-saving boiler, characterized in that: The system includes a water jacket shell, a furnace chamber, a staged air supply assembly, and a heat exchange assembly. The water jacket shell is a closed water cavity structure formed by an outer insulation shell and an inner furnace wall. The top of the water jacket shell has an arc-shaped structure and an air outlet. The furnace chamber is located inside the water jacket shell, and a grate and furnace door are located at the bottom of the furnace chamber. A lower ash cleaning port is provided below the grate for cleaning ash and slag in the grate area. The staged air supply assembly includes a primary air channel, a secondary air channel, and a tertiary air channel. The primary air channel is located below the grate, and the secondary and tertiary air channels are symmetrically arranged on the side walls of the furnace chamber. The heat exchange assembly... The assembly includes a preheating tube horizontally arranged above the furnace and multiple annular fire tubes located above the preheating tubes. The multiple annular fire tubes are arranged in multiple staggered layers along the flue gas flow direction, so that the flue gas rises from the furnace and flows back and forth between adjacent annular fire tubes in sequence, forming nine continuous flue gas heat exchange cycles. During the flow of the nine cycles, the flue gas comes into contact with the outer wall of the preheating tube, the outer wall of the annular fire tube, and the inner furnace wall of the water jacket shell in sequence to achieve multi-stage heat exchange. The side wall of the water jacket shell has an upper ash cleaning port corresponding to the installation area of ​​the annular fire tube for cleaning the ash adhering to the outer wall of the annular fire tube.

2. The multi-fuel nine-pass high-efficiency energy-saving boiler as described in claim 1, characterized in that: The outer side of the water jacket housing is equipped with a water level gauge for monitoring the liquid level in the water chamber.

3. The multi-fuel nine-pass high-efficiency energy-saving boiler as described in claim 1, characterized in that: The nine flue gas heat exchange return paths are formed by the staggered arrangement of multiple layers of annular fire tubes. Each time the flue gas passes through a layer of annular fire tubes and completes a turnback, it corresponds to completing one heat exchange return path, thereby extending the contact time between the flue gas and the heat exchange components and the heat exchange path.

4. The multi-fuel nine-pass high-efficiency energy-saving boiler as described in claim 1, characterized in that: The primary air duct, secondary air duct, and tertiary air duct are all connected to the same blower, and each air duct is independently equipped with an air volume regulating device. By adjusting the air volume of each air duct, the different combustion requirements of coal, firewood, and biomass pellets can be adapted.

5. The multi-fuel nine-pass high-efficiency energy-saving boiler as described in claim 1, characterized in that: The preheating tube is fixedly arranged horizontally above the furnace, with its bottom facing directly into the furnace interior to directly absorb the radiant heat generated by fuel combustion in the furnace, thus achieving the first stage of heat exchange.

6. The multi-fuel nine-pass high-efficiency energy-saving boiler as described in claim 1, characterized in that: The multiple annular fire tubes are arranged in a staggered, multi-layered manner along the vertical direction, with the positions of adjacent layers of annular fire tubes being staggered. This allows the flue gas to flow back and forth in an S-shape between adjacent annular fire tubes, ensuring that the flue gas fully flows through the outer wall of each annular fire tube.

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