A natural gas boiler flue gas waste heat recovery equipment

Abstract

This utility model relates to the field of waste heat recovery technology and discloses a waste heat recovery device for natural gas boiler flue gas. The device includes a base plate, a heat pump a fixedly connected to the top of the base plate, a connecting pipe fixedly connected to the output end of the heat pump a, a heat exchanger fixedly connected to the other end of the connecting pipe, a central water tank fixedly connected to the top of the base plate, an air source heat pump fixedly connected to the top of the base plate, a high-temperature water tank fixedly connected to the top of the base plate, a heat pump b fixedly connected to the top of the base plate, a boiler body fixedly connected to the top of the base plate, and a chimney fixedly connected to the top of the base plate. In this utility model, high-temperature flue gas from the boiler is transported to the heat exchanger for counter-current heat exchange with demineralized water. After the demineralized water is heated by the heat exchange, it is heated by the air source heat pump and stored in the high-temperature water tank, supplying the boiler as needed. This achieves efficient recovery of waste heat from the flue gas and utilization of water for heating, significantly improving energy utilization and flue gas treatment efficiency.

Description

Technical Field

[0001] This utility model relates to the field of waste heat recovery technology, and in particular to a waste heat recovery device for natural gas boiler flue gas. Background Technology

[0002] A natural gas boiler is a special type of equipment that uses natural gas as its main fuel to heat water to certain parameters through combustion and then outputs the heat energy. It is widely used in industrial production, district heating, and commercial hot water supply. It is one of the core equipment for clean energy heating and heat supply. Flue gas waste heat recovery equipment is an energy-saving device installed at the tail end of combustion equipment such as boilers, kilns, and industrial furnaces. It is specifically used to recover the heat that is not fully utilized in the flue gas and convert it into usable energy, thereby improving the energy utilization efficiency of the entire combustion system and reducing energy waste and pollutant emissions.

[0003] Common structures for waste heat recovery from flue gas in some natural gas boilers mainly include three types: finned tube heat exchangers, spiral finned tube heat exchangers, and condensing heat exchangers. Finned tube heat exchangers increase the heat exchange area by adding metal fins to the outside of the base tube. High-temperature flue gas flows through the channels between the fins and transfers heat to the water inside the tube. They are suitable for medium and low temperature waste heat recovery. Spiral finned tube heat exchangers use a spiral fin design to enhance flue gas turbulence and improve heat exchange efficiency. They are often used in scenarios with high flue gas temperatures. Condensing heat exchangers target water vapor in the flue gas, using a low-temperature medium to condense the water vapor and release latent heat, while simultaneously recovering sensible heat, resulting in higher heat exchange efficiency.

[0004] In existing technologies, some natural gas boiler flue gas waste heat recovery devices do not optimize the matching of flue gas flow path and water flow velocity, which easily leads to heat exchange dead zones and local overheating. This not only affects heat transfer efficiency, but also causes equipment blockage due to the accumulation of condensate and impurities in the flue gas, further reducing operational stability and the sustainability of waste heat recovery. Therefore, in order to address the above shortcomings, a natural gas boiler flue gas waste heat recovery device is proposed to solve the above problems. Utility Model Content

[0005] To overcome the above shortcomings, this utility model provides a natural gas boiler flue gas waste heat recovery device, which aims to improve the problem of low sustainability in some existing waste heat recovery devices.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A waste heat recovery device for natural gas boiler flue gas includes a base plate, a heat pump a fixedly connected to the top of the base plate, a connecting pipe fixedly connected to the output end of the heat pump a, a heat exchanger fixedly connected to the other end of the connecting pipe, a central water tank fixedly connected to the top of the base plate, an air source heat pump fixedly connected to the top of the base plate, a high-temperature water tank fixedly connected to the top of the base plate, a heat pump b fixedly connected to the top of the base plate, a boiler body fixedly connected to the top of the base plate, and a chimney fixedly connected to the top of the base plate.

[0008] As a further description of the above technical solution:

[0009] A purification box is fixedly connected to the top of the base plate, a water storage tank is fixedly connected to the bottom of the purification box, and a water outlet pipe is fixedly connected to the outside of the water storage tank.

[0010] As a further description of the above technical solution:

[0011] A grid plate is fixedly connected to the middle of the interior of the purification box, and a placement box is fixedly connected to the top of the grid plate. The placement box contains multiple packing blocks.

[0012] As a further description of the above technical solution:

[0013] The purification box is fixedly connected to a fixed pipe inside, and multiple spray heads are fixedly connected to the bottom of the fixed pipe. A water inlet pipe is fixedly connected to the outside of each spray head.

[0014] As a further description of the above technical solution:

[0015] An activated carbon plate is fixedly connected to the upper part of the interior of the purification box, and the exterior of the purification box is fixedly connected to the exterior of the chimney through the connecting pipe.

[0016] As a further description of the above technical solution:

[0017] The exterior of the heat exchanger is fixedly connected to the exterior of the central water tank via the connecting pipe, and the exterior of the central water tank is fixedly connected to the exterior of the air source heat pump via the connecting pipe.

[0018] As a further description of the above technical solution:

[0019] The exterior of the air source heat pump is fixedly connected to the exterior of the high-temperature water tank through the connecting pipe; the exterior of the high-temperature water tank is fixedly connected to the exterior of the heat pump b through the connecting pipe; and the exterior of the heat pump b is fixedly connected to the exterior of the boiler body through the connecting pipe.

[0020] As a further description of the above technical solution:

[0021] The exterior of the high-temperature water tank is fixedly connected to the exterior of the heat pump b through the connecting pipe, and the exterior of the connecting pipe is fixedly connected to the exterior of the purification box through the connecting pipe.

[0022] This utility model has the following beneficial effects:

[0023] 1. In this utility model, the high-temperature flue gas from the boiler is transported to the heat exchanger for countercurrent heat exchange with the demineralized water. After the demineralized water is heated by the heat exchange, it is heated by the air source heat pump and stored in the high-temperature water tank, which is supplied to the boiler as needed. This achieves efficient recovery of waste heat from the flue gas and utilization of water heating. Moreover, the flue gas purification process is continuous, which greatly improves energy utilization and flue gas treatment efficiency.

[0024] 2. In this utility model, the waste gas is transported to the bottom of the purification box through the connecting pipe. The waste gas moves upward in the purification box and is purified by the packing blocks placed inside the box. At the same time, the spray head is turned on to spray the upward waste gas, washing the dust downward. Finally, it is filtered and purified by the activated carbon plate, which realizes the function of purifying the waste gas and reduces the dust content in the waste gas, thereby achieving the effect of protecting the environment. Attached Figure Description

[0025] Figure 1 This is a three-dimensional schematic diagram of a natural gas boiler flue gas waste heat recovery device proposed in this utility model.

[0026] Figure 2 This is a schematic diagram of the chimney structure of a natural gas boiler flue gas waste heat recovery device proposed in this utility model;

[0027] Figure 3 This is a schematic diagram of the purification box of a natural gas boiler flue gas waste heat recovery device proposed in this utility model.

[0028] Legend:

[0029] 1. Heat pump a; 2. Connecting pipe; 3. Heat exchanger; 4. Central water tank; 5. Air source heat pump; 6. High temperature water tank; 7. Heat pump b; 8. Boiler body; 9. Purification box; 10. Chimney; 11. Activated carbon plate; 12. Water storage tank; 13. Water outlet pipe; 14. Grid plate; 15. Placement box; 16. Packing block; 17. Fixing pipe; 18. Spray head; 19. Water inlet pipe; 20. Base plate. Detailed Implementation

[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0031] A waste heat recovery device for flue gas from a natural gas boiler, referring to Figure 1 and Figure 2 The system includes a base plate 20, with a heat pump a1 fixedly connected to the top of the base plate 20. This heat pump a1 provides energy support for maintaining the initial temperature of the demineralized water or for auxiliary heating. A connecting pipe 2 is fixedly connected to the output end of the heat pump a1, handling the transmission of demineralized water, high-temperature hot water, and purified flue gas. A heat exchanger 3 is fixedly connected to the other end of the connecting pipe 2, responsible for heat transfer between the natural gas boiler flue gas and the demineralized water. The exterior of the heat exchanger 3 is fixedly connected to the exterior of the central water tank 4 via the connecting pipe 2. The exterior of the central water tank 4 is also fixedly connected to the exterior of the air source heat pump 5 via the connecting pipe 2. The base plate 20... A central water tank 4 is fixedly connected to the top, which is used to store 50℃ demineralized water after heat exchange by heat exchanger 3. An air source heat pump 5 is fixedly connected to the top of the bottom plate 20. It uses low-grade heat energy in the ambient air to heat the 50℃ hot water output from the central water tank 4 to 80℃ during normal and off-peak electricity periods, thereby achieving efficient energy enhancement and storage. The exterior of the air source heat pump 5 is fixedly connected to the exterior of the high-temperature water tank 6 through a connecting pipe 2. The exterior of the high-temperature water tank 6 is fixedly connected to the exterior of the heat pump b7 through a connecting pipe 2. The exterior of the heat pump b7 is fixedly connected to the exterior of the boiler body 8 through a connecting pipe 2.

[0032] Specifically, the components are fixed on the base plate 20. The heat pump a provides initial energy support for the demineralized water. The heat exchanger 3 efficiently transfers the heat between the flue gas and the demineralized water, achieving full recovery of the waste heat of the flue gas. The middle water tank 4 stores the 50°C demineralized water after heat exchange. Then, the air source heat pump 5 utilizes the low-grade heat energy of the environment to raise the water temperature to 80°C during peak and off-peak electricity periods, which is both efficient in energy storage and reduces energy consumption costs. The high-temperature water tank 6 and the heat pump b are further connected to the system to supply energy to the boiler body 8.

[0033] A high-temperature water tank 6 is fixedly connected to the top of the base plate 20. This tank stores 80°C hot water heated by the air source heat pump 5, providing a high-temperature heat source for subsequent boiler water replenishment or other heating needs. The exterior of the high-temperature water tank 6 is fixedly connected to the exterior of the heat pump b7 via a connecting pipe 2. The exterior of the connecting pipe 2 is also fixedly connected to the exterior of the purification tank 9 via another connecting pipe 2. The heat pump b7, fixedly connected to the top of the base plate 20, is responsible for further heating or maintaining the temperature of the 80°C hot water output from the high-temperature water tank 6, ensuring that the water entering the boiler body 8 meets the requirements for boiler operation. Temperature requirements: The top of the base plate 20 is fixedly connected to the boiler body 8, which is the natural gas combustion and main heating equipment and the source of flue gas generation. It also receives high-temperature hot water after being treated by the waste heat recovery system. The top of the base plate 20 is fixedly connected to the chimney 10, which is the flue gas emission channel and is responsible for discharging the clean flue gas treated by the purification box 9 into the atmosphere at high altitude. The upper part of the interior of the purification box 9 is fixedly connected to the activated carbon plate 11, which undertakes the adsorption and filtration functions of pollutants in the flue gas. The exterior of the purification box 9 is fixedly connected to the exterior of the chimney 10 through the connecting pipe 2.

[0034] Specifically, the high-temperature water tank 6 can store 80℃ hot water, providing a stable high-temperature heat source for boiler water replenishment and other heating needs, ensuring convenient heating. The heat pump b can further heat or keep the hot water at a constant temperature, ensuring that the water entering the boiler body 8 meets the operating temperature requirements, improving the boiler's operating efficiency. The activated carbon plate 11 in the purification box 9 can efficiently adsorb and filter pollutants in flue gas, working with the chimney 10 to achieve clean flue gas emission at high altitude, reducing air pollution and meeting environmental protection requirements.

[0035] Reference Figure 1 and Figure 3 A purification box 9 is fixedly connected to the top of the base plate 20. This box is responsible for removing pollutants such as dust, sulfides, nitrogen oxides, and odors from the flue gas after heat exchange with the heat exchanger 3. A water storage tank 12 is fixedly connected to the bottom of the purification box 9. This tank collects and temporarily stores the wastewater after dust suppression spraying. A water outlet pipe 13 is fixedly connected to the outside of the water storage tank 12. This pipe directs the dust-laden wastewater collected in the water storage tank 12 to the outside. A grid plate 14 is fixedly connected to the middle of the interior of the purification box 9. This plate is responsible for fixing the box 15 and simultaneously diverting the upward-flowing exhaust gas. A [missing information - likely a device or component] is fixedly connected to the top of the grid plate 14. The placement box 15 is responsible for neatly fixing multiple packing blocks 16. Multiple packing blocks 16 are set inside the placement box 15. They are responsible for removing harmful gases from the exhaust gas through chemical reactions such as adsorption and neutralization. The purification box 9 is fixedly connected to the fixing pipe 17, which is responsible for fixing the spray head 18 and evenly distributing the spray water delivered by the water inlet pipe 19 to each spray head 18. Multiple spray heads 18 are fixedly connected to the bottom of the fixing pipe 17. They are responsible for converting the high-pressure water flow into a fine water mist to spray and wash the upward-flowing exhaust gas. The spray head 18 is fixedly connected to the outside of the water inlet pipe 19.

[0036] Specifically, the fine water mist sprayed from the spray head 18 can first spray and rinse the flue gas to initially remove pollutants such as dust. After the flue gas is diverted by the grid plate 14, the packing blocks 16 placed in the box 15 efficiently remove harmful gases such as sulfides and nitrogen oxides through adsorption and neutralization reactions. The activated carbon plate 11 further filters the gas, realizing multi-stage purification of pollutants. The water storage tank 12 collects the spray wastewater and delivers it in a directional manner through the outlet pipe 13 to avoid secondary pollution. The fixed pipe 17 ensures that the spray water is evenly distributed and improves the purification efficiency.

[0037] The implementation principle of this application embodiment is as follows: First, after the boiler body 8 is started and running, natural gas is burned inside to generate high-temperature flue gas. Then, the flue gas is first transported to the heat exchanger 3, where it undergoes countercurrent heat exchange with 20°C demineralized water introduced from the outside, achieving preliminary recovery of waste heat from the flue gas. After heat exchange, the temperature of the flue gas drops to about 60°C, and then enters the purification box 9 through the connecting pipe 2. The flue gas entering the purification box 9 moves upward and first contacts the grid plate 14 to divert the flue gas, making the flue gas diffuse upward evenly. Then, the diverted flue gas passes through multiple packing blocks 16. The packing block 16 removes harmful gases from the flue gas through chemical reactions such as adsorption and neutralization. At the same time, multiple spray heads 18 are turned on, converting the high-pressure water flow delivered by the water inlet pipe 19 into water mist, which sprays and washes the flue gas, washing away dust and other particulate matter downwards, which falls into the water storage tank 12 and is then transported to the outside through the water outlet pipe 13. The sprayed flue gas continues to rise and passes through the activated carbon plate 11 to adsorb and filter the residual pollutants and odors in the flue gas. The purified clean flue gas is then transported to the chimney 10 through the connecting pipe 2 and discharged into the atmosphere from the chimney 10.

[0038] Meanwhile, the 20°C demineralized water is pumped into heat exchanger 3, where it undergoes countercurrent heat exchange with the high-temperature flue gas, raising its temperature to 50°C. It then enters the central water tank 4 for storage via connecting pipe 2. During periods of normal and off-peak electricity, the 50°C hot water in the central water tank 4 is transported to the air source heat pump 5. The air source heat pump 5 utilizes low-grade heat energy from the ambient air to heat the water to 80°C. The heated hot water then enters the high-temperature water tank 6 for temporary storage via connecting pipe 2. When the boiler body 8 needs water replenishment or heating, the 80°C hot water in the high-temperature water tank 6 is transported to heat pump b7. Heat pump b7 further heats or maintains the temperature of the water to ensure it meets the boiler's operating requirements. Finally, it is transported to the boiler body 8 via connecting pipe 2 to participate in the boiler's operating cycle. Meanwhile, heat pump a1 continues to operate, providing energy support for maintaining the initial temperature of the demineralized water.

[0039] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A waste heat recovery device for natural gas boiler flue gas, comprising a base plate (20), characterized in that: A heat pump a (1) is fixedly connected to the top of the base plate (20), a connecting pipe (2) is fixedly connected to the output end of the heat pump a (1), a heat exchanger (3) is fixedly connected to the other end of the connecting pipe (2), a central water tank (4) is fixedly connected to the top of the base plate (20), an air source heat pump (5) is fixedly connected to the top of the base plate (20), a high-temperature water tank (6) is fixedly connected to the top of the base plate (20), a heat pump b (7) is fixedly connected to the top of the base plate (20), a boiler body (8) is fixedly connected to the top of the base plate (20), and a chimney (10) is fixedly connected to the top of the base plate (20).

2. The waste heat recovery equipment for natural gas boiler flue gas according to claim 1, characterized in that: A purification box (9) is fixedly connected to the top of the base plate (20), a water storage tank (12) is fixedly connected to the bottom of the purification box (9), and a water outlet pipe (13) is fixedly connected to the outside of the water storage tank (12).

3. The waste heat recovery equipment for natural gas boiler flue gas according to claim 2, characterized in that: A grid plate (14) is fixedly connected to the middle of the interior of the purification box (9), and a placement box (15) is fixedly connected to the top of the grid plate (14). Multiple packing blocks (16) are arranged inside the placement box (15).

4. The waste heat recovery equipment for natural gas boiler flue gas according to claim 2, characterized in that: The purification box (9) is fixedly connected to a fixed pipe (17), and a plurality of spray heads (18) are fixedly connected to the bottom of the fixed pipe (17). The spray heads (18) are fixedly connected to a water inlet pipe (19).

5. The waste heat recovery equipment for natural gas boiler flue gas according to claim 2, characterized in that: An activated carbon plate (11) is fixedly connected to the upper part of the interior of the purification box (9), and the exterior of the purification box (9) is fixedly connected to the exterior of the chimney (10) through the connecting pipe (2).

6. The waste heat recovery equipment for natural gas boiler flue gas according to claim 2, characterized in that: The exterior of the heat exchanger (3) is fixedly connected to the exterior of the central water tank (4) through the connecting pipe (2), and the exterior of the central water tank (4) is fixedly connected to the exterior of the air source heat pump (5) through the connecting pipe (2).

7. The waste heat recovery equipment for natural gas boiler flue gas according to claim 5, characterized in that: The exterior of the air source heat pump (5) is fixedly connected to the exterior of the high-temperature water tank (6) through the connecting pipe (2), the exterior of the high-temperature water tank (6) is fixedly connected to the exterior of the heat pump b (7) through the connecting pipe (2), and the exterior of the heat pump b (7) is fixedly connected to the exterior of the boiler body (8) through the connecting pipe (2).

8. The waste heat recovery equipment for natural gas boiler flue gas according to claim 2, characterized in that: The exterior of the high-temperature water tank (6) is fixedly connected to the exterior of the heat pump b (7) through the connecting pipe (2), and the exterior of the connecting pipe (2) is fixedly connected to the exterior of the purification box (9) through the connecting pipe (2).

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