Hot water boiler utilizing waste heat of high-temperature waste gas

Abstract

The invention discloses a hot water boiler utilizing waste heat of high-temperature waste gas. The hot water boiler solves the problems that existing waste heat recovery equipment cannot adapt to the high-temperature tar-containing waste gas, and is low in heat exchange efficiency, inconvenient to clean and maintain and poor in operation stability. The boiler comprises a boiler frame, a water storage frame and a plurality of hot air conveying pipes. An air inlet pipe and an air outlet pipe are arranged on the left side and the right side above the boiler frame respectively, the water storage frame is arranged in the boiler frame, the hot air conveying pipes are transversely and densely arranged in the water storage frame and completely immersed in circulating water, the two ends of each hot air conveying pipe are communicated with the air inlet pipe and the air outlet pipe respectively, and a circulating water inlet and a circulating water outlet are formed in the top of the water storage frame. A single-stage direct dividing wall type immersion heat exchange structure is adopted, the waste heat recovery efficiency is high, large-flow high-temperature waste gas can be stably adapted, an online cleaning structure and a rigid supporting structure are matched, operation is reliable, maintenance is convenient and fast, and the device is suitable for various industrial high-temperature waste gas waste heat recovery scenes.

Description

Technical Field

[0001] This invention relates to the field of industrial waste heat recovery and utilization equipment, specifically to a hot water boiler that utilizes the waste heat of high-temperature exhaust gas. Background Technology

[0002] Industrial production processes generate a large amount of high-temperature waste gas carrying residual heat. Direct discharge of such gas not only causes serious energy waste but also creates thermal pollution, which does not meet the needs of energy conservation and emission reduction in industrial development.

[0003] In the prior art, Chinese utility model patent with publication number CN204255130U discloses a waste heat recovery system for high-temperature exhaust gas from oil pretreatment. This system targets high-temperature exhaust gas exceeding 85°C discharged from the oil cooler in the oil pretreatment workshop. It features a waste heat recovery structure centered on a waste heat absorption tower, primarily composed of a fan, air heater, oil cooler, cyclone separator, waste heat absorption tower, spray pump, and shell-and-tube heat exchanger. The core waste heat recovery principle is as follows: after being dusted by the cyclone separator, the high-temperature exhaust gas enters the waste heat absorption tower, passing through the packing layer from bottom to top. It directly contacts and exchanges heat with the cold water sprayed from the main spray pipe within the packing layer, forming a counter-current gas-liquid contact. The cold water absorbs the heat from the exhaust gas, becoming hot water, which is then pumped into the shell-and-tube heat exchanger for indirect heat exchange and heat release. The cooled water is then returned to the spray pipe for circulating spraying, thus achieving waste heat recovery from the high-temperature exhaust gas. This system increases the gas-liquid contact area through the packing layer, thereby improving the heat recovery rate of medium and low temperature exhaust gas. At the same time, it can simultaneously remove odors and dust impurities from the exhaust gas, and has certain application value in the scenario of low temperature dusty exhaust gas waste heat recovery in the oil pretreatment industry.

[0004] However, this scheme uses direct gas-liquid contact spray heat exchange, which is only suitable for medium-low temperature exhaust gases around 85℃. For high-temperature exhaust gases of 200℃, direct spray heat exchange will cause violent vaporization of the spray water, resulting in drastic pressure fluctuations in the heat exchange chamber and extremely poor heat exchange stability. It is also prone to safety hazards such as equipment cavitation and pipeline vibration, and cannot meet the requirements for continuous and stable heat exchange of high-temperature exhaust gases. Moreover, this existing technology adopts a two-stage heat exchange mode of "exhaust gas-spray water-purified water", which involves multiple heat transfer links and large overall heat loss. It can only achieve a small temperature drop for medium-low temperature exhaust gases and cannot simultaneously achieve the heat exchange target of large temperature difference. The waste heat recovery efficiency is difficult to meet the utilization requirements of high-temperature exhaust gases. At the same time, this scheme relies on a packing layer to achieve gas-liquid contact heat exchange. The effective heat exchange area is limited by the amount of packing, making it difficult to form a sufficient heat exchange area in a limited equipment space. In addition, its heat exchange chamber does not adopt an optimized structure adapted to the heat exchange unit, resulting in a large overall equipment volume, low space utilization, and inability to achieve efficient heat exchange in a compact structure. This scheme employs a counter-current layout where waste gas flows from bottom to top and sprayed water flows from top to bottom. This results in a long airflow path and high flow resistance, making it unsuitable for consistently meeting the heat exchange demands of large-volume, high-temperature waste gas. It is prone to airflow deviation and uneven heat exchange, leading to significant fluctuations in overall heat exchange efficiency and an inability to maintain stable waste heat recovery. Furthermore, this existing technology utilizes only a single form of waste heat utilization and cannot directly produce usable industrial hot water.

[0005] In summary, existing waste heat recovery systems based on spray-filled towers can only be adapted to medium- and low-temperature waste gas scenarios with low dust and oil content. They cannot solve the problem of efficient waste heat recovery from large-flow-rate, high-temperature industrial waste gas at 200℃, nor can they meet the requirements of efficient heat exchange. Therefore, there is an urgent need to develop a hot water boiler with high heat exchange efficiency and stable structure that utilizes the waste heat of high-temperature waste gas. Summary of the Invention

[0006] The purpose of this application is to provide a hot water boiler that utilizes the waste heat of high-temperature exhaust gas.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A hot water boiler utilizing the waste heat of high-temperature exhaust gas includes a boiler frame 1, a water storage frame 2 disposed inside the boiler frame 1, and multiple hot air delivery pipes disposed inside the water storage frame 2. An air inlet pipe 31 and an air outlet pipe 32 are respectively disposed on the left and right sides above the boiler frame 1 for inputting high-temperature exhaust gas and outputting cooled exhaust gas, respectively. The water storage frame 2 is filled with circulating water. The multiple hot air delivery pipes are arranged horizontally and densely within the water storage frame 2 and are completely submerged in the circulating water, with their ends connected to the air inlet pipe 31 and the air outlet pipe 32, respectively. The boiler frame 1 also has a circulating water inlet 41 and a circulating water outlet 42 connected to the top of the water storage frame 2, for inputting low-temperature circulating water and outputting heated hot water, respectively.

[0009] Preferably, the boiler frame 1 is divided into an air inlet chamber 11, a heat exchange chamber 12, and an air outlet chamber 13 from left to right; the air inlet chamber 11 is connected to the air inlet pipe 31 and the air inlet end of the hot air conveying pipe respectively; the water storage frame 2 is installed inside the heat exchange chamber 12; the air outlet chamber 13 is connected to the air outlet end of the hot air conveying pipe and the air outlet pipe 32 respectively.

[0010] Preferably, the water storage frame 2 is further provided with a support frame for fixing the hot air delivery pipe, and the support frame is composed of multiple round supports 51 arranged longitudinally inside the water storage frame 2.

[0011] Preferably, the boiler frame 1 is further provided with iron plate reinforcing ribs 6.

[0012] Preferably, the boiler frame 1 is also provided with a multi-functional drainage structure, which includes three drain outlets at the bottom of the boiler frame 1. The drain outlets on the left and right sides are used to discharge water or cleaning liquid, and the drain outlet in the middle is used to discharge water or cleaning liquid after cleaning the water storage frame 2 separately.

[0013] Preferably, the air inlet pipe 31 is provided with a chemical injection port 71 connected to the boiler frame 1 for injecting chemical solution during cleaning, and the air outlet pipe 32 is provided with a water injection port 72 connected to the boiler frame 1 for injecting clean water during cleaning.

[0014] Preferably, the top of the boiler frame 1 is also provided with an automatic air vent valve 81 for discharging air from the circulating water inside the water storage frame 2.

[0015] Preferably, the top of the boiler frame 1 is also provided with a water supply interface 82 for replenishing circulating water to the water storage frame 2.

[0016] Preferably, the hot air delivery pipe is a 304 stainless steel pipe.

[0017] Preferably, a support base 83 is also connected to the bottom of the boiler frame 1.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. This project addresses the core issues of traditional multi-stage heat transfer methods, such as high heat loss, inability of direct contact heat transfer to handle 200℃ high-temperature waste gas, insufficient effective heat exchange area, and low waste heat recovery efficiency, by integrating a heat exchange structure that combines indirect wall immersion heat exchange with single-stage direct heat exchange. The high-temperature waste gas flows through horizontally densely arranged hot air delivery pipes completely submerged in circulating water. Heat is directly transferred to the target circulating water outside the pipes through the stainless steel pipe walls in a single pass, eliminating intermediate heat exchange media and secondary transfer links. This maximizes the effective heat exchange area within a compact cylindrical water storage frame. In this way, the safety hazards of traditional spray heat exchange, such as severe water vaporization, cavity pressure fluctuations, and equipment cavitation under high-temperature conditions, as well as the problem of progressive heat loss caused by multi-stage heat exchange, can be stably achieved to achieve the goal of bidirectional large temperature difference heat exchange, with high-temperature exhaust gas decreasing from 200℃ to 120℃ and circulating water increasing from 75℃ to 95℃. The waste heat recovery efficiency is significantly improved, while the equipment structure is greatly simplified, reducing manufacturing costs and failure points. It achieves efficient, safe, and continuous recovery of waste heat from high-temperature industrial exhaust gas, taking into account both extreme heat exchange efficiency and adaptability to complex operating conditions.

[0020] 2. This design utilizes a fully optimized fluid flow structure that integrates a three-chamber, pressure-stabilizing, and flow-equalizing airflow path with a top-mounted convection circulating water path. This addresses the issues of uneven airflow distribution, biased heat transfer, and laminar flow in short-circuited water paths inherent in traditional heat exchange equipment under high-flow conditions, leading to fluctuating heat exchange efficiency, uneven heat transfer, and high energy consumption. By expanding and buffering the inlet chamber, the high-temperature exhaust gas is transformed into a more stable airflow, facilitating its even distribution to each hot air delivery pipe. This ensures the stability and uniformity of heat exchange under fluctuating flow rates.

[0021] 3. This solution addresses the problems of traditional heat exchange equipment, such as tar deposits clogging heat exchange tubes, incomplete cleaning, frequent downtime for disassembly and maintenance, and inability to maintain heat exchange efficiency long-term, through a multi-functional drainage structure with independent zone control and a separate convection-type chemical and water injection interface, which allows for independent zoned cleaning and drainage of the hot air delivery pipe system and the water storage frame system. The separate design of the inlet chemical injection interface and the outlet water injection interface allows for thorough mixing of the chemical solution and clean water within the heat exchange tubes, effectively dissolving and peeling off high-viscosity tar deposits from the tube walls. The entire cleaning process can be completed without disassembling the equipment. This avoids the problems of blind spots, tar residue, and cross-contamination associated with traditional equipment cleaning. It can flexibly adapt to different levels of scaling and cleaning needs, significantly shorten cleaning downtime, reduce labor maintenance costs, ensure no decrease in heat exchange efficiency during long-term operation, and extend the equipment's service life. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the internal structure of a hot water boiler that utilizes the waste heat of high-temperature exhaust gas, as shown in the front view, according to an embodiment of this case.

[0023] Figure 2 This is a side view of the internal structure of a hot water boiler that utilizes the waste heat of high-temperature exhaust gas, according to an embodiment. Detailed Implementation

[0024] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The components of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following drawings indicate similar items; therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. These embodiments are only used to explain the present invention and are not intended to limit the scope of protection of the present invention.

[0026] This embodiment provides a hot water boiler that utilizes the waste heat of high-temperature exhaust gas. It is suitable for the waste heat recovery of 200°C high-temperature gasification tail gas in a biomass gasification plant. It is required to cool the tail gas to 120°C, heat the 75°C circulating water to 95°C, and effectively treat the high-viscosity tar deposits in the tail gas.

[0027] like Figure 1 and Figure 2As shown in the figure, an embodiment of the present invention discloses a hot water boiler utilizing the waste heat of high-temperature exhaust gas, comprising: a boiler frame 1, a water storage frame 2 disposed inside the boiler frame 1, and multiple hot air conveying pipes disposed inside the water storage frame 2; an air inlet pipe 31 and an air outlet pipe 32 are respectively disposed on the left and right sides above the boiler frame 1 for inputting high-temperature exhaust gas and outputting cooled exhaust gas, respectively; the water storage frame 2 is filled with circulating water; the multiple hot air conveying pipes are arranged horizontally and densely inside the water storage frame 2 and are completely submerged in the circulating water, with their two ends connected to the air inlet pipe 31 and the air outlet pipe 32, respectively; the boiler frame 1 is also provided with a circulating water inlet 41 and a circulating water outlet 42 connected to the top of the water storage frame 2, for inputting low-temperature circulating water and outputting heated hot water, respectively. In specific implementation, the boiler frame can be welded from steel plates, forming a horizontal sealed cavity structure; the water storage frame 2 is a cylindrical water storage frame with a sealed cylindrical structure, also made of steel, and coaxially fixed inside the boiler frame 1 for filling circulating water; multiple hot air delivery pipes 10 are made of seamless steel pipes, densely arranged laterally along the axial direction of the boiler frame 1, all of which penetrate the left and right end walls of the cylindrical water storage frame, and the entire pipe is completely within the circulating water filling range of the water storage frame 2, with no exposed sections. The hot air delivery pipes 10 are only used to deliver hot air from the air inlet pipe 31 and will not allow water to enter; the air inlet pipe 31 is welded to the top left side of the boiler frame 1, and the air outlet pipe 32 is welded to the top right side. The air inlet pipe 31 is sealed and connected to the air inlet end of all the hot air delivery pipes 10, and the air outlet pipe 32 is sealed and connected to the air outlet end of all the hot air delivery pipes 10. The air inlet pipe is used to connect to a 200℃, 8000m 3 The industrial high-temperature waste gas is discharged at a rate of / h, and the exhaust duct 32 is used to discharge the cooled 120℃, 8000m³ waste gas. 3 / h exhaust gas; The top left end of the cylindrical water storage frame is welded with a circulating water inlet 41, and the top right end is welded with a circulating water outlet 42. The circulating water inlet is used to continuously input low-temperature circulating water at 75℃, and the circulating water outlet is used to output hot water heated to 95℃. During operation, high-temperature exhaust gas enters from the air inlet pipe, flows laterally through all hot air delivery pipes, and transfers heat directly to the completely submerged circulating water outside the pipes through the pipe walls, completing indirect heat exchange; low-temperature circulating water enters the water storage frame from the circulating water inlet, fills the entire cavity and surrounds all hot air delivery pipes, absorbs heat and heats up, and is stably output from the circulating water outlet. Specifically, indirect heat exchange means that two fluids with different temperatures (hot fluid and cold fluid) are completely separated by a solid heat-conducting wall (metal pipe wall, plate, etc.), and do not come into contact with or mix with each other throughout the process. Heat is transferred only through the heat conduction of the solid wall and the convection heat transfer between the fluid and the wall, ultimately achieving the heat exchange goal of cooling the hot fluid and heating the cold fluid.

[0028] As described above, this invention, through the arrangement of boiler frame 1, water storage frame 2, multiple hot air conveying pipes, air inlet pipe 31, air outlet pipe 32, circulating water inlet 41, and circulating water outlet 42, constitutes a gas-liquid isolated indirect heat exchange structure. This allows high-temperature exhaust gas to flow inside the hot air conveying pipes while the circulating water is completely submerged outside the pipes, with no direct contact between the gas and liquid phases. The heat exchange process is stable and safe, fundamentally avoiding the problems of violent vaporization of high-temperature water, cavity pressure fluctuations, equipment cavitation, and pipeline vibration caused by direct spray heat exchange in existing technologies. It can stably adapt to the heat exchange requirements of 200℃ high-temperature exhaust gas. This design utilizes a single-stage indirect heat exchange, eliminating any intermediate heat exchange medium or secondary transfer links, to directly transfer heat to the target cold fluid. This achieves the goal of cooling the hot fluid and heating the cold fluid in one step, realizing a single-stage direct heat exchange mode. It eliminates the intermediate steps of existing two-stage heat exchange technologies, significantly reducing heat loss. Combined with the long-distance heat exchange path formed by the horizontally densely arranged hot air delivery pipes, it stably achieves the bidirectional large temperature difference heat exchange target of "waste gas cooling from 200℃ to 120℃ and circulating water heating from 75℃ to 95℃," significantly improving waste heat recovery efficiency. Furthermore, the cylindrical water storage frame and the horizontally densely arranged hot air delivery pipes ensure that multiple pipes are horizontally densely arranged and completely submerged in the circulating water. The entire outer wall of each pipe is an effective heat exchange surface, creating a much larger effective heat exchange area within the limited equipment space than existing packing layer structures. This significantly improves the space utilization and heat exchange efficiency per unit volume, achieving high-efficiency heat exchange in a compact structure. Furthermore, this design employs a direct-flow air path layout with inlet and outlet pipes on the left and right sides of the boiler frame, combined with a horizontally integrated hot air delivery pipe running through the water storage frame. This allows the high-temperature exhaust gas, entering through the left-side inlet pipe, to be directly and evenly distributed to each horizontally arranged hot air delivery pipe. After flowing directly through the pipes in a horizontal direction, it exits through the right-side outlet pipe. The airflow path is short, and the flow resistance is extremely low, making it stably adaptable to 8000m³ boilers. 3 The system meets the high-flow-rate, high-temperature waste gas heat exchange requirements. Simultaneously, the horizontal direct-flow air path design ensures uniform distribution and consistent flow velocity of the high-temperature waste gas within each hot air delivery pipe, avoiding the airflow deviation and uneven heat exchange problems caused by the counter-flow layout of existing technologies. This guarantees the stability and consistency of the overall heat exchange efficiency of the equipment. Furthermore, this design employs a water path layout where both the circulating water inlet and outlet are located at the top of the water storage frame. Combined with the hot air delivery pipes fully immersed in the circulating water, the low-temperature circulating water enters the water storage frame from the top inlet and, under gravity, fills the entire water storage frame from top to bottom. This ensures full and uniform contact with the entire outer wall of the hot air delivery pipes, absorbing the heat transferred from the pipe walls and uniformly heating up. Finally, it stably outputs hot water meeting the required temperature from the top outlet, guaranteeing full contact and uniform heat exchange between the circulating water and the heat exchange interface within the water storage frame. This achieves stable and uniform heating of the circulating water, further ensuring the overall effectiveness of waste heat recovery.

[0029] In a preferred embodiment, the boiler frame 1 is divided into an air inlet chamber 11, a heat exchange chamber 12, and an air outlet chamber 13 from left to right; the air inlet chamber 11 is connected to the air inlet pipe 31 and the air inlet end of the hot air conveying pipe respectively; the water storage frame 2 is installed inside the heat exchange chamber 12; the air outlet chamber 13 is connected to the air outlet end of the hot air conveying pipe and the air outlet pipe 32 respectively. In practice, the boiler frame 1 can be divided into three independent sealed chambers from left to right by two vertical dividing steel plates: an air inlet chamber 11, a heat exchange chamber 12, and an air outlet chamber 13. The left dividing steel plate has through holes that match the number and outer diameter of the hot air delivery pipes. The air inlet end of the hot air delivery pipe passes through the through hole and is sealed to the air inlet chamber. The top of the air inlet chamber is sealed to the air inlet pipe. The middle heat exchange chamber is the main chamber of the boiler frame, and a cylindrical water storage frame is coaxially fixed inside the heat exchange chamber. The right dividing steel plate has through holes that match the number and outer diameter of the hot air delivery pipes. The air outlet end of the hot air delivery pipe passes through the through hole and is sealed to the air outlet chamber. The top of the air outlet chamber is sealed to the air outlet pipe. During operation, high-temperature exhaust gas first enters the air intake chamber through the air intake pipe, and then is evenly distributed to each hot air delivery pipe; after heat exchange, low-temperature exhaust gas enters the air outlet chamber from the air outlet end of the hot air delivery pipe and is collected, and finally discharged uniformly through the air outlet pipe.

[0030] Understandably, if the air inlet duct directly connects to a densely packed bundle of hot air delivery pipes, the few delivery pipes directly facing the inlet duct will be directly impacted by the high-speed airflow, while the delivery pipes far from the edge or corners of the inlet duct will be unable to receive airflow, resulting in extremely low flow rates or even backflow, leading to severe airflow deviation problems. Therefore, this design employs a three-chamber independent separation design. The air inlet chamber acts as a pressure buffer, facilitating the even distribution of hot air to multiple hot air delivery pipes. This solves the problems of uneven airflow distribution and overload of some delivery pipes / heat exchanger tubes when large volumes of exhaust gas enter, ensuring consistent airflow velocity and flow rate in each hot air delivery pipe and achieving uniform heat exchange across the entire cross-section. Furthermore, the heat exchanger chamber is completely isolated from the inlet and outlet chambers, forming an independent heat exchange space. This avoids the risk of cross-flow between high-temperature exhaust gas and the circulating water system, improving the sealing and safety of the equipment operation. In addition, the outlet chamber enables unified collection and discharge of exhaust gas, reducing airflow resistance.

[0031] In a preferred embodiment, the water storage frame 2 is further provided with a support frame for fixing the hot air delivery pipes. The support frame consists of multiple circular supports 51 arranged longitudinally inside the water storage frame 2. Specifically, the circular supports 51 are made of 304 stainless steel, and all circular supports are evenly arranged longitudinally along the axial direction of the water storage frame. The two ends of each circular support are welded and fixed to the inner walls of the front and rear ends of the water storage frame, respectively. Each circular support can have a semi-circular positioning groove that matches the outer diameter of the hot air delivery pipe along the axial direction. All hot air delivery pipes are sequentially inserted into the corresponding positioning grooves. Alternatively, they can be directly fixed by welding to form a stable tube bundle structure. In this way, the longitudinally arranged circular supports form a multi-point support structure, which can stably fix the densely arranged hot air delivery pipes, preventing the pipes from shifting, vibrating, or deforming under the impact of high-temperature airflow and the buoyancy of water, and ensuring the arrangement stability of the heat exchange tube bundle. On the other hand, it can also serve as a reinforcing support structure built into the water storage frame 2, improving the pressure-bearing capacity of the water storage frame and ensuring long-term stable operation. In addition, the round support made of 304 stainless steel has excellent corrosion resistance and can be used for a long time in the circulating water environment without the risk of rust damage, and will not pollute the circulating water quality.

[0032] In a preferred embodiment, the boiler frame 1 is further provided with iron plate reinforcing ribs 6. Specifically, iron plate reinforcing ribs are welded to the outer wall of the boiler frame, with the rib thickness matching the boiler frame wall thickness. The reinforcing ribs are welded circumferentially to the outer wall of the frame, and have two directions, allowing them to be welded in an interlaced manner to form a grid-like reinforcing structure. Thus, the reinforcing rib structure can improve structural strength and optimize the vibration resistance of the equipment without increasing the boiler frame wall thickness.

[0033] In a preferred embodiment, the boiler frame 1 is further provided with a multi-functional drainage structure, which includes three drain outlets located at the bottom of the boiler frame 1: a left drain outlet 14, a middle drain outlet 15, and a right drain outlet 16. The left and right drain outlets are used to discharge water or cleaning fluid, while the middle drain outlet is used to discharge water or cleaning fluid after cleaning the water storage frame 2 separately. In specific implementation, the three drain outlets are equidistantly arranged along the axial direction of the boiler frame; the left and right drain outlets are respectively connected to the air inlet and air outlet chambers of the boiler frame, and are used to discharge water or cleaning fluid after cleaning the heat exchange tubes; the middle drain outlet is separately connected to the bottom of the inner cavity of the water storage frame, completely isolated from the air inlet and air outlet chambers, and is only used to discharge water or cleaning fluid after cleaning inside the water storage frame; each drain outlet can be equipped with a flange-type shut-off valve, which can be independently controlled for on / off. During cleaning operations, the left and right drain outlets can be opened individually to complete the cleaning and drainage of the hot air delivery pipes; the middle drain outlet can also be opened individually to complete the cleaning and drainage of the inside of the water storage frame; or all three drain outlets can be opened simultaneously to complete the rapid emptying and cleaning of the entire system.

[0034] As described above, the three-drainage design of this project enables independent cleaning and drainage of the hot air delivery pipe system and the water storage frame system. This allows for targeted removal of impurities and tar deposits from different parts, avoiding cross-contamination and ensuring more thorough cleaning. The drain outlet at the bottom allows for complete emptying of the equipment, preventing cleaning fluid and water from remaining inside and preventing corrosion of the equipment's inner walls and blockage of pipes during long-term shutdowns. In this way, the problem of existing technologies being unable to conveniently clean heat exchange components online is solved, allowing for the periodic removal of tar deposits from the pipe walls and maintaining the equipment's heat exchange efficiency over the long term.

[0035] In a preferred embodiment, the air inlet pipe 31 is provided with a chemical injection port 71 connected to the boiler frame 1 for injecting chemical solution during cleaning, and the air outlet pipe 32 is provided with a water injection port 72 connected to the boiler frame 1 for injecting clean water during cleaning. Specifically, the chemical injection port is connected to the air inlet cavity of the boiler frame for injecting a special tar-removing chemical solution during cleaning. During the cleaning operation, clean water is first injected into the hot air delivery pipe through the water injection port of the air outlet pipe to fill all pipes. Then, the special cleaning chemical solution is injected through the chemical injection port of the air inlet pipe. The clean water and the chemical solution form convection within the pipes, thoroughly mixing to dissolve and remove tar deposits from the pipe walls, which are finally discharged through the drain outlets on the left and right sides at the bottom. Thus, the separate water injection and chemical dosing interface design allows clean water and chemical solution to convect and mix within the hot air delivery pipe, significantly improving the mixing uniformity and dissolution effect of the chemical solution. This solves the problems of uneven mixing and blind spots in existing cleaning solutions. The interface is directly connected to the air inlet and outlet chambers, allowing the cleaning solution to directly enter all hot air delivery pipes and thoroughly clean the inner wall of each heat exchanger tube, resulting in a significantly improved cleaning effect. Furthermore, the water injection and chemical dosing functions are independently controlled, allowing for flexible adjustment of the cleaning process to meet different scaling cleaning needs, thus broadening the applicability.

[0036] In a preferred embodiment, an automatic air vent valve 81 is also provided at the top of the boiler frame 1 to discharge air from the circulating water inside the water storage frame 2. Specifically, the air inlet of the vent valve is sealed to the top of the inner cavity of the water storage frame. The automatic vent valve is set with an opening pressure threshold. When air in the circulating water inside the water storage frame precipitates and accumulates at the top of the cavity, causing the internal pressure to exceed the threshold, the float descends, causing the valve to open automatically and discharge the accumulated air. After the air is discharged, the internal pressure returns to normal, and the float rises, causing the valve to close automatically, preventing the circulating water from overflowing. In this way, air precipitated in the circulating water system can be automatically and in real time discharged, solving the problem of air bubbles forming air resistance on the hot air delivery pipe wall. This avoids problems such as decreased heat exchange efficiency, localized overheating, and pipe wall corrosion caused by air resistance, thus maintaining the heat exchange performance of the equipment over a long period.

[0037] In a preferred embodiment, the top of the boiler frame 1 is also provided with a water supply interface 82 for replenishing circulating water to the water storage frame 2. This facilitates the replenishment of circulating water losses, ensures that the water storage frame maintains a normal operating level, guarantees that all hot air delivery pipes are completely submerged in the circulating water, and ensures stable heat exchange.

[0038] In a preferred embodiment, the hot air delivery pipe is made of 304 stainless steel. 304 stainless steel possesses excellent thermal conductivity, enabling rapid heat transfer between high-temperature exhaust gas and circulating water, ensuring high heat exchange efficiency. Furthermore, it exhibits strong corrosion resistance and high-temperature resistance, allowing for long-term stable operation in environments with 200°C high-temperature exhaust gas and circulating water. It resists corrosion from tar and acidic impurities in the exhaust gas, is not prone to rusting or cracking, and significantly extends the service life of the heat exchange tube.

[0039] In a preferred embodiment, a support base 83 is also connected to the bottom of the boiler frame 1. In practice, the support base 83 raises the boiler body by 200mm, which facilitates the operation of the bottom drain port and prevents corrosion from contact with the ground.

[0040] In summary, the operation process of the hot water boiler utilizing the waste heat of high-temperature exhaust gas in this embodiment is mainly divided into a heat exchange operation process and a cleaning and maintenance process. The two processes are carried out independently, and the cleaning and maintenance process is implemented after the boiler is shut down, as detailed below:

[0041] Heat exchange operation process:

[0042] like Figure 1 The exhaust gas at a high temperature of 200℃ travels at 8000m 3 A flow rate of [amount] / h enters the boiler's intake chamber through the inlet pipe, which evenly distributes the exhaust gas into each hot air delivery pipe. The high-temperature exhaust gas flows from left to right within the hot air delivery pipes. Because the pipes are completely submerged in 75°C circulating water within the water storage frame, the heat carried by the exhaust gas is rapidly transferred to the circulating water outside the pipes through the stainless steel pipe walls, achieving indirect heat exchange. After heat exchange, the exhaust gas temperature drops to 120°C, and after entering the outlet chamber, it is collected and discharged through the outlet pipe, achieving the required cooling level. The circulating water within the water storage frame absorbs heat, its temperature rising from 75°C to 95°C, and is continuously output through the circulating water outlet for use as industrial hot water, achieving efficient recovery of waste heat from the high-temperature exhaust gas. Furthermore... Figure 1 The red arrow in the image indicates the airflow direction of this application.

[0043] Cleaning and maintenance process

[0044] When a boiler has been running for a period of time and a decrease in heat exchange efficiency is detected (e.g., circulating water heating temperature is below 90℃, exhaust gas outlet temperature is above 130℃), it is determined that impurities such as tar have accumulated on the walls of the hot air conveying pipes. The boiler is then shut down and a cleaning and maintenance process is initiated. Specific steps are as follows:

[0045] ① Close the exhaust valves of the air inlet and outlet pipes, as well as the water valves of the circulating water inlet and outlet, to ensure that the boiler is completely isolated from the external pipelines;

[0046] ② Inject clean water into the boiler through the water inlet of the air outlet pipe until the hot air delivery pipe is completely submerged. Then inject special alkaline solution for removing tar through the chemical injection inlet of the air inlet pipe. The clean water and the chemical solution are fully mixed inside the boiler and soaked for 30 minutes to dissolve and soften the tar deposits on the pipe wall.

[0047] ③ Open the drain outlets on the left and right sides at the bottom of the boiler frame to completely drain the cleaning liquid mixed with tar and complete the overall cleaning of the boiler; if there are impurities deposited on the inner wall of the water storage frame, open the middle drain outlet separately and inject clean water into the water storage frame through the water injection interface to clean the inside of the water storage frame separately. The wastewater after cleaning is discharged from the middle drain outlet.

[0048] ④ Close all drain outlets, inject clean water again through the water injection interface, and rinse the inside of the boiler and the hot air delivery pipe with clean water. The wastewater after rinsing is discharged from the drain outlets on the left and right sides. Repeat rinsing 2-3 times to ensure that there is no chemical residue or tar residue.

[0049] ⑤ Open the automatic air vent valve and the circulating water inlet valve, and inject circulating water into the water storage frame until the set liquid level is reached. After cleaning and maintenance, the boiler can be restarted and enter the heat exchange operation process.

[0050] As stated above, this case protects a hot water boiler that utilizes the waste heat of high-temperature exhaust gas, and all technical solutions that are the same as or similar to this case should be considered to fall within the scope of protection of this case.

Claims

1. A hot water boiler utilizing waste heat from high-temperature exhaust gas, characterized in that, The boiler includes a boiler frame (1), a water storage frame (2) inside the boiler frame (1), and multiple hot air delivery pipes inside the water storage frame (2). An air inlet pipe (31) and an air outlet pipe (32) are respectively provided on the left and right sides above the boiler frame (1) for the input of high-temperature exhaust gas and the output of exhaust gas after cooling. The water storage frame (2) is filled with circulating water. The multiple hot air delivery pipes are arranged horizontally and densely inside the water storage frame (2) and are completely submerged in the circulating water. Both ends are connected to the air inlet pipe (31) and the air outlet pipe (32) respectively. The boiler frame (1) is also provided with a circulating water inlet (41) and a circulating water outlet (42) connected to the top of the water storage frame (2) for the input of low-temperature circulating water and the output of hot water after heating.

2. The hot water boiler utilizing high-temperature waste gas heat according to claim 1, characterized in that, The boiler frame (1) is divided into an air inlet chamber (11), a heat exchange chamber (12), and an air outlet chamber (13) from left to right. The air inlet chamber (11) is connected to the air inlet pipe (31) and the air inlet end of the hot air conveying pipe. The water storage frame (2) is installed inside the heat exchange chamber (12). The air outlet chamber (13) is connected to the air outlet end of the hot air conveying pipe and the air outlet pipe (32).

3. The hot water boiler utilizing high-temperature waste gas heat according to claim 1, characterized in that, The water storage frame (2) is also equipped with a support frame for fixing the hot air delivery pipe. The support frame is composed of multiple round branches (51) arranged longitudinally inside the water storage frame (2).

4. The hot water boiler utilizing high-temperature waste gas heat according to claim 1, characterized in that, The boiler frame (1) is also provided with iron plate reinforcing ribs (6).

5. The hot water boiler utilizing high-temperature waste gas heat according to claim 1, characterized in that, The boiler frame (1) is also provided with a multi-functional drainage structure, which includes three drainage outlets at the bottom of the boiler frame (1). The left and right drainage outlets are used to discharge water or cleaning liquid, and the middle drainage outlet is used to discharge water or cleaning liquid after cleaning the water storage frame (2) separately.

6. The hot water boiler utilizing waste heat from high-temperature exhaust gas according to claim 1 or 5, characterized in that, The air inlet pipe (31) is provided with a chemical injection interface (71) connected to the boiler frame (1) for injecting chemical solution during cleaning. The air outlet pipe (32) is provided with a water injection interface (72) connected to the boiler frame (1) for injecting clean water during cleaning.

7. The hot water boiler utilizing waste heat from high-temperature exhaust gas according to claim 1 or 4, characterized in that, An automatic air vent valve (81) is also provided on the top of the boiler frame (1) to discharge air from the circulating water inside the water storage frame (2).

8. The hot water boiler utilizing waste heat from high-temperature exhaust gas according to claim 1, characterized in that, The top of the boiler frame (1) is also provided with a water supply interface (82) for replenishing circulating water to the water storage frame (2).

9. The hot water boiler utilizing high-temperature waste gas heat according to claim 1, characterized in that, The hot air delivery pipe is made of 304 stainless steel.

10. The hot water boiler utilizing high-temperature waste gas heat according to claim 1, characterized in that, The bottom of the boiler frame (1) is also connected to a support base (83).

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