Boiler blowdown waste heat recovery device

Abstract

This utility model relates to the field of boiler blowdown technology and discloses a boiler blowdown waste heat recovery device, including a blowdown expansion container. The blowdown expansion container is connected to a liquid heat exchanger and a gas heat exchanger through a pipeline system. The gas heat exchanger and the liquid heat exchanger are respectively connected to a secondary heat exchange cylinder. The secondary heat exchange cylinder is an inverted conical structure with a spirally coiled exhaust pipe inside. The inlet end of the exhaust pipe is located at the lower part of the secondary heat exchange cylinder. The outlet end of the exhaust pipe is connected to a guide ring located at the upper part of the interior of the secondary heat exchange cylinder. The inner ring of the guide ring has guide nozzles along its circumference. The water inlet on the secondary heat exchange cylinder is located at the upper part of the guide ring. This utility model can not only realize the smooth heating of water injected into the secondary heat exchange cylinder by the exhaust pipe, but also realize the transport and dissolution of hot gas into the water, avoiding the phenomenon of water entering the exhaust pipe and causing corrosion of the exhaust pipe, thus ensuring heat exchange efficiency and heat exchange effect.

Description

Technical Field

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

[0002] Boiler blowdown primarily involves discharging a certain amount of water from the boiler to reduce internal pressure and remove salts and impurities. This process typically occurs during boiler operation to ensure water quality and prevent the accumulation of impurities and salts that could affect normal boiler operation. The main functions of blowdown are: 1. Ensuring safe boiler operation: Regular blowdown removes impurities and salts from the boiler water, preventing their accumulation and thus preventing scaling, corrosion, or blockage on the boiler's heating surfaces, ensuring safe operation. 2. Maintaining stable water quality: Regular blowdown effectively maintains boiler water quality, preventing excessively hard or alkaline water that could adversely affect the boiler's inner walls. 3. Reducing blowdown heat loss: In certain situations, properly controlling the blowdown volume can reduce heat loss and improve boiler thermal efficiency.

[0003] In the process of boiler blowdown, the efficiency and effect of heat recovery remain the most important issues in order to achieve energy conservation and emission reduction. Based on this, invention patent CN118031202A discloses a boiler blowdown waste heat recovery device, including a blowdown expansion container and a pipeline system. The blowdown port of the blowdown expansion container is connected to a liquid heat exchange structure, which uses wastewater to heat clean water. The exhaust port is connected to a gas heat exchange structure, which uses blowdown steam to heat air. The liquid heat exchange structure and the gas heat exchange structure are respectively connected to a secondary heat exchange structure. The secondary heat exchange structure includes a secondary heat exchange cylinder, which is an inverted cone shape. An exhaust pipe is installed inside the secondary heat exchange cylinder. The exhaust pipe is spirally bent in an inverted cone shape inside the secondary heat exchange cylinder. Multiple exhaust holes are opened on the exhaust pipe, and check valves are installed in the exhaust holes.

[0004] The above-mentioned device can improve the efficiency of waste heat utilization, reduce boiler energy consumption, and reduce pollutant emissions, thus achieving certain energy-saving and emission-reduction effects. However, in actual use, although a check valve is installed in the exhaust port of the exhaust pipe in the secondary heat exchanger in the above scheme, it can only prevent water from flowing back into the exhaust pipe when the water in the secondary heat exchanger has passed the exhaust port. During the exhaust process, the water will flow into the exhaust pipe as the check valve opens, which will not only corrode the pipe but also hinder the normal emission of gas and reduce heat transfer efficiency.

[0005] Therefore, there is an urgent need for a boiler blowdown waste heat recovery device that can heat the water in the secondary heat exchanger without allowing water to flow into the exhaust pipe. Utility Model Content

[0006] The purpose of this invention is to provide a boiler blowdown waste heat recovery device that can not only smoothly heat the water injected into the secondary heat exchange cylinder through the exhaust pipe, but also realize the transport and dissolution of hot air into the water, avoiding the phenomenon of water entering the exhaust pipe and causing corrosion, thus ensuring heat exchange efficiency and heat exchange effect.

[0007] The present invention adopts the following technical solution:

[0008] A boiler blowdown waste heat recovery device includes a blowdown expansion tank. The blowdown expansion tank is connected to a liquid heat exchanger and a gas heat exchanger via a pipeline system. The gas heat exchanger and the liquid heat exchanger are respectively connected to a secondary heat exchange cylinder. The secondary heat exchange cylinder has an inverted conical structure and a spirally coiled exhaust pipe inside. The inlet end of the exhaust pipe is located on the lower side of the secondary heat exchange cylinder. The outlet end of the exhaust pipe is connected to a gas guide ring located above the interior of the secondary heat exchange cylinder. The inner ring of the gas guide ring has gas guide nozzles along its circumference. A water injection port on the secondary heat exchange cylinder is located on the upper part of the gas guide ring.

[0009] Preferably, the air guide nozzle is inclined downwards.

[0010] Preferably, a water distribution ring is provided on the secondary heat exchange cylinder above the air guide ring, and water distribution holes are provided along the circumference of the inner ring of the water distribution ring.

[0011] Preferably, a filter is provided between the gas heat exchanger and the secondary heat exchange cylinder.

[0012] Preferably, the filter includes a housing, and a filter screen cylinder is disposed inside the housing. One end of the filter screen cylinder is fixedly disposed on the inner wall of the housing, and a discharge pipe communicating with the inner wall of the filter screen cylinder is disposed on the housing at that end.

[0013] Preferably, a rotating shaft is rotatably arranged inside the housing, and a cleaning brush is provided on the rotating shaft. The cleaning brush is L-shaped and covers the end of the filter screen cylinder and the outer wall. A ash discharge valve is provided at the bottom of the housing.

[0014] Preferably, the rotating shaft is driven by a motor mounted on the housing.

[0015] Preferably, the bottom of the shell is provided with a conical sludge collection bin, and the ash discharge valve is located at the bottom of the sludge collection bin.

[0016] Compared with existing technologies, the advantages of this invention are as follows: By designing the exhaust pipe as a spiral coil structure extending to the upper part of the secondary heat exchange cylinder and connecting it with the air guide ring, this invention fundamentally avoids the risk of submerging the exhaust port when the water level inside the cylinder is too high. The elimination of the check valve simplifies the pipeline structure and reduces the failure rate. The air guide nozzle has no moving parts, ensuring high long-term operational stability and reducing maintenance costs. Located above the water surface, the air guide nozzle ensures that even when the secondary heat exchange cylinder is filled with water, the exhaust channel remains unobstructed, completely solving the problems of pipeline corrosion and obstructed gas emission caused by backflow. Furthermore, the circumferential distribution design of the air guide nozzle ensures uniform spraying of high-temperature gas, preventing localized overheating, while the gas directly contacts the upper water flow, improving heat exchange efficiency.

[0017] Furthermore, the spirally coiled exhaust pipe extends the residence time of high-temperature gas within the secondary heat exchanger and, through the inverted conical cylinder structure, creates upward turbulence, enhancing gas-liquid heat exchange. The guide ring disperses the gas to multiple guide nozzles, increasing the contact area between the gas and water, further optimizing heat transfer and reducing waste heat loss. The inverted conical secondary heat exchanger, combined with the exhaust pipe design at the lower inlet, forms a "low-in, high-out" airflow path, utilizing the principle of natural hot air rise to reduce power consumption. Attached Figure Description

[0018] Figure 1 This is a front view of an embodiment of this application;

[0019] Figure 2 This is a partial cross-sectional view of the secondary heat exchanger cylinder according to an embodiment of this application;

[0020] Figure 3 This is a partial cross-sectional view of the filter in an embodiment of this application. Detailed Implementation

[0021] The present invention will now be described clearly and completely with reference to the accompanying drawings and embodiments:

[0022] like Figures 1 to 3 As shown, the boiler blowdown waste heat recovery device of this utility model includes a blowdown expansion container 1, which is connected to a liquid heat exchanger 2 and a gas heat exchanger 3 through a pipeline system. The gas heat exchanger 3 and the liquid heat exchanger 2 are respectively connected to a secondary heat exchange cylinder 4. Since the above content is all prior art, its working principle can be referred to the content disclosed in the invention patent with publication number CN118031202A. In order to highlight the inventive points of this application, the content of the prior art section above will not be described in detail.

[0023] The secondary heat exchanger 4 is an inverted conical structure with a spirally coiled exhaust pipe 5 inside. The inlet end of the exhaust pipe 5 is located on the lower side of the secondary heat exchanger 4. The outlet end of the exhaust pipe 5 is connected to a guide ring 6 located at the upper part of the secondary heat exchanger 4. A guide cavity is formed inside the guide ring 6. A guide nozzle 7 is opened along the circumference of the inner ring of the guide ring 6, which communicates with the guide cavity. The water inlet on the secondary heat exchanger 4 is located on the upper part of the guide ring 6. This arrangement enables the water flow to impact the airflow discharged below during the water injection process into the secondary heat exchanger 4. This achieves rapid contact and fusion of water flow and airflow, reduces the upward escape of airflow, and improves the utilization rate of heat. This application fundamentally avoids the risk of submerging the exhaust port when the water level inside the secondary heat exchanger 4 is too high by designing the exhaust pipe 5 as a spiral coil structure that extends to the upper part of the secondary heat exchanger 4 and connects with the air guide ring 6. This eliminates the need for a check valve, simplifying the piping structure and reducing the failure rate. The air guide nozzle 7 has no moving parts, ensuring high long-term operational stability and reducing maintenance costs. Located above the water surface, the air guide nozzle 7 ensures that the exhaust channel remains unobstructed even when the secondary heat exchanger 4 is filled with water, completely solving the problems of pipe corrosion and obstructed gas emission caused by backflow. Furthermore, the circumferential distribution design of the air guide nozzle 7 ensures uniform spraying of high-temperature gas, preventing localized overheating, while the gas directly contacts the upper water flow, improving heat exchange efficiency.

[0024] Furthermore, the circumferential distribution design of the air guide nozzle 7 ensures uniform spraying of high-temperature gas, avoiding localized overheating. Simultaneously, the gas directly contacts the upper water flow, improving heat exchange efficiency. Additionally, the spirally coiled exhaust pipe 5 extends the residence time of high-temperature gas within the secondary heat exchange cylinder 4 and, through its inverted conical cylinder structure, creates upward turbulence, enhancing gas-liquid heat exchange and demonstrating strong practicality.

[0025] Furthermore, in this embodiment, each air-guiding nozzle 7 is tilted downwards to facilitate the airflow into the water and prevent water from flowing back into the air-guiding ring 6 and the exhaust pipe 5. A water-distributing ring 8 is provided on the secondary heat exchange cylinder 4 above the air-guiding ring 6. The inner ring of the water-distributing ring 8 has water-distributing holes along its circumference. The even distribution of water through these holes prevents concentrated water flow from impacting a specific area, ensuring that the cold water is evenly dispersed within the secondary heat exchange cylinder 4 and fully contacts the high-temperature gas ejected from the air-guiding ring 6 below. Simultaneously, this helps the water flow evenly cover the entire heat exchange area, avoiding sudden temperature changes in localized areas, ensuring balanced heat transfer, and improving the stability of the system operation. By positioning the water-distributing ring 8 above the air-guiding ring 6, the water, after being evenly distributed through the water-distributing holes, forms a dynamic mixing layer with the high-temperature gas ejected from the air-guiding ring 6 in the middle of the secondary heat exchange cylinder 4. This optimizes the gas-liquid contact area and avoids the common "gas-to-gas, water-to-water" phenomenon in traditional heat exchange structures, allowing for more efficient heat transfer from the gas to the water.

[0026] Furthermore, in this embodiment, a filter is provided between the gas heat exchanger 3 and the secondary heat exchange cylinder 4 to filter the gas entering the exhaust pipe 5, reducing the scouring and wear caused by impurities entrained in the airflow on the inner wall of the exhaust pipe 5, and also preventing impurities from entering the water and affecting the water quality. Specifically, the filter includes a housing 9, with a maintenance cover 16 detachably provided on one side of the housing 9 by bolts. A filter screen cylinder 10 is provided inside the housing 9, and an air inlet is provided on the outer wall of the housing 9. The air inlet is connected to the gas heat exchanger 3 through a pipe. The filter screen cylinder 10 increases the filtration area and improves the filtration efficiency. One end of the filter screen cylinder 10 is fixedly provided on the inner wall of the housing 9, and an exhaust pipe 11 is provided on the housing 9 at this end, which is connected to the inner wall of the filter screen cylinder 10. The gas entering the housing 9 is filtered by the filter screen cylinder 10 and then enters the exhaust pipe 11, which is then transported to the exhaust pipe 5.

[0027] A rotating shaft is rotatably mounted inside the housing 9, and a cleaning brush 12 is mounted on the shaft. The cleaning brush 12 is L-shaped, and initially, the bristles cover the end and outer wall of the filter cylinder 10. A dust discharge valve 13 is located at the bottom of the housing 9. By periodically controlling the rotation of the cleaning brush 12, the dust filtered from the surface of the filter cylinder 10 can be cleaned in a timely manner, ensuring filtration efficiency. The filtered dust can be discharged through the opening of the dust discharge valve 13. Preferably, the rotating shaft is driven by a motor 14 mounted on the housing 9. The cleaning operation of the filter cylinder 10 can be achieved by periodically turning on the motor 14, improving the convenience of operation. The motor 14 can be a motor with a self-locking structure to ensure stability in a static state. The motor 14 is connected to the rotating shaft by a coupling. In addition, a conical dirt collection bin 15 is provided at the bottom of the housing 9. The dirt collection bin 15 is designed to facilitate the rapid fall of cleaned dust, preventing accumulation inside the housing 9. The dust discharge valve 13 is located at the bottom of the dirt collection bin 15.

[0028] This invention fundamentally avoids the risk of submerging the exhaust port when the water level inside the secondary heat exchanger 4 is too high by designing the exhaust pipe 5 as a spiral coiled structure that extends to the upper part of the secondary heat exchanger 4 and connects with the air guide ring 6. It eliminates the need for a check valve, simplifying the pipeline structure and reducing the failure rate. The air guide nozzle 7 has no moving parts, ensuring high long-term operational stability and reducing maintenance costs. Located above the water surface, the air guide nozzle 7 ensures that the exhaust channel remains unobstructed even when the secondary heat exchanger 4 is filled with water, completely solving the problems of pipeline corrosion and obstructed gas emission caused by backflow. Furthermore, the circumferential distribution design of the air guide nozzle 7 ensures uniform spraying of high-temperature gas, preventing localized overheating, while the gas directly contacts the upper water flow, improving heat exchange efficiency. In addition, by installing a filter between the gas heat exchanger 3 and the secondary heat exchanger 4, the airflow entering the exhaust pipe 5 can be filtered, reducing the erosion and wear caused by impurities in the airflow on the inner wall of the exhaust pipe 5, and preventing impurities from entering the water and affecting water quality, making it highly practical.

Claims

1. A boiler blowdown waste heat recovery device, comprising a blowdown expansion tank, wherein the blowdown expansion tank is connected to a liquid heat exchanger and a gas heat exchanger via a pipeline system, and the gas heat exchanger and the liquid heat exchanger are respectively connected to a secondary heat exchange cylinder, characterized in that: The secondary heat exchange cylinder is an inverted conical structure with a spirally coiled exhaust pipe inside. The inlet end of the exhaust pipe is located on the lower side of the secondary heat exchange cylinder. The outlet end of the exhaust pipe is connected to a guide ring located above the interior of the secondary heat exchange cylinder. The inner ring of the guide ring has a guide nozzle along its circumference. The water inlet on the secondary heat exchange cylinder is located on the upper part of the guide ring.

2. The boiler blowdown waste heat recovery device according to claim 1, characterized in that: The air guide nozzle is tilted downwards.

3. The boiler blowdown waste heat recovery device according to claim 2, characterized in that: A water distribution ring is provided on the secondary heat exchange cylinder above the air guide ring, and water distribution holes are provided along the circumference of the inner ring of the water distribution ring.

4. The boiler blowdown waste heat recovery device according to claim 1, characterized in that: A filter is provided between the gas heat exchanger and the secondary heat exchange cylinder.

5. The boiler blowdown waste heat recovery device according to claim 4, characterized in that: The filter includes a housing, and a filter screen cylinder is disposed inside the housing. One end of the filter screen cylinder is fixedly disposed on the inner wall of the housing, and a discharge pipe communicating with the inner wall of the filter screen cylinder is disposed on the housing at that end.

6. The boiler blowdown waste heat recovery device according to claim 5, characterized in that: The housing is rotatably mounted with a rotating shaft, and a cleaning brush is mounted on the rotating shaft. The cleaning brush is L-shaped and covers the end of the filter screen and the outer wall. A ash discharge valve is located at the bottom of the housing.

7. The boiler blowdown waste heat recovery device according to claim 6, characterized in that: The rotating shaft is driven by a motor mounted on the housing.

8. The boiler blowdown waste heat recovery device according to claim 6, characterized in that: The bottom of the shell is provided with a conical sludge collection bin, and the ash discharge valve is located at the bottom of the sludge collection bin.

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