Heat energy recovery device for desalting and dedusting of high-temperature flue gas

Abstract

The present invention discloses a high-temperature flue gas desalination, dust removal and heat energy recovery device, which comprises a heat exchanger main body with heat exchange tubes. The heat exchange tubes are vertically installed in the heat exchanger main body. An ash cleaning mechanism for cleaning the inside of the heat exchange tubes is arranged outside the heat exchanger main body. The ash cleaning mechanism comprises a lifting rod, a rotating rod and a telescopic rod which are vertically and parallelly arranged. One end of the telescopic rod is fixedly connected with the lifting rod, and a guide sleeve through which the rotating rod passes is arranged at the other end of the telescopic rod. The rotating rod is rotationally matched with the guide sleeve. A lifting motor for driving the lifting rod to move up and down is connected to the lifting rod. The upper end of the rotating rod is connected with a rotating motor for driving the rotating rod to rotate. A dust cleaning brush for contacting the inner peripheral surface of the heat exchange tube is arranged at the lower end of the rotating rod; a dust cleaning port for the dust cleaning brush to enter the heat exchange tube downward is arranged at the top of the inlet pipe box. The number of the dust cleaning ports is equal to the number of the heat exchange tubes. Each dust cleaning port is respectively located above each heat exchange tube, and a sealing cover is respectively arranged on each dust cleaning port.

Description

Technical Field

[0001] The present invention relates to a high-temperature flue gas desalination, dust removal and heat energy recovery device, belonging to the technical field of furnace gas heat recovery in chemical production. Background Art

[0002] At present, a large amount of waste acid is generated in industrial production, especially in the chemical production field. How to reasonably utilize and treat waste acid has become the top priority of current resource recovery and reuse, especially environmental protection requirements. Waste acid cracking and regeneration is the main method for the reasonable treatment and utilization of waste acid at present. The main process of waste acid cracking is that the waste acid is incinerated and cracked in an incinerator, then goes to a waste heat boiler, and then through conversion and absorption. Since the waste acid may contain a large amount of metal ions, a large amount of metal salts (such as nickel sulfate, sodium sulfate, etc.) or metal oxides are formed during incineration. When the flue gas with dust and high salt enters the waste heat boiler (fire tube boiler), when the flue gas is cooled to below 900 °C, the metal salt components (the boiling point of nickel sulfate is 840 °C, the boiling point of sodium sulfate is 884 °C, etc.) precipitate due to the temperature decrease, resulting in easy fouling and ash accumulation on the heat pipes of the waste heat boiler (fire tube boiler). During long-term operation, the heat pipes of the boiler are severely fouled and the corrosion is accelerated. This greatly affects the heat transfer efficiency, reduces the service life of the boiler, and even causes serious accidents such as boiler explosion in severe cases.

[0003] The existing technology for treating fouling of boiler heat pipes is as follows: When the fouling of the waste heat boiler is severe, it must be shut down for manual ash cleaning, which consumes a large amount of manpower. Moreover, the ash cleaning during shutdown purging causes a large amount of ash scale substances to accumulate in downstream equipment. The ash scale substances will be purged into the catalyst bed of the converter, resulting in an increase in the pressure drop of the catalyst bed and affecting the performance of the catalyst at the same time. Therefore, the current ash cleaning and purging in the boiler section do not fundamentally solve the harm of metal salt components in high-salt flue gas to the system device. Therefore, under the condition of high-salt and high-temperature flue gas, the fouling and ash accumulation rate of the waste heat boiler is relatively fast, seriously affecting the continuity and long-term operation of the entire device system's safe production. Summary of the Invention

[0004] The purpose of the present invention is to provide a high-temperature flue gas desalination, dust removal and heat energy recovery device, which is used to solve the technical problem that the boiler under the condition of high-salt and high-temperature flue gas in the prior art needs to be shut down for purging and ash cleaning, affecting the continuity of system operation. At the same time, it also solves the technical problem that the ash scale will enter downstream equipment during purging, resulting in a reduction in system performance.

[0005] The present invention adopts the following technical solution: a high-temperature flue gas desalination, dust removal and heat energy recovery device, which includes a heat exchanger main body with heat exchange tubes. The heat exchanger main body adopts a vertical structure, and the heat exchange tubes are installed vertically in the heat exchanger main body. An upper tube sheet is provided in the upper part of the heat exchanger main body, and a lower tube sheet is provided in the lower part. Above the upper tube sheet is an inlet header, and below the lower tube sheet is an outlet header. A flue gas inlet is provided on the side of the inlet header, and a flue gas outlet is provided on the side of the outlet header. The upper end of the heat exchange tube passes through the upper tube sheet and leads into the inlet header, and the lower end of the heat exchange tube passes through the lower tube sheet and is communicated with the outlet header; the bottom of the outlet header is a tapered structure with a large upper part and a small lower part, and a slag discharge port is provided at the bottom end of the tapered structure; outside the heat exchanger main body, there is a dust cleaning mechanism for cleaning the inside of the heat exchange tubes. The dust cleaning mechanism includes a lifting rod and a rotating rod that are vertically and parallelly arranged. A horizontally arranged telescopic rod is connected between the upper ends of the lifting rod and the rotating rod. One end of the telescopic rod is fixedly connected to the lifting rod, and the other end of the telescopic rod is provided with a guide sleeve through which the rotating rod passes. The rotating rod is rotationally matched with the guide sleeve. A lifting motor for driving the lifting rod to move up and down is connected to the lifting rod, and a rotating motor for driving the rotating rod to rotate is connected to the upper end of the rotating rod. A dust cleaning brush for contacting the inner peripheral surface of the heat exchange tube is provided at the lower end of the rotating rod; a dust cleaning port for the dust cleaning brush to enter the heat exchange tube downward is provided at the top of the inlet header. The number of dust cleaning ports is equal to the number of heat exchange tubes. Each dust cleaning port is located above each heat exchange tube, and each dust cleaning port is respectively provided with a sealing cover.

[0006] A jacket tube is hermetically sleeved on the outer periphery of the part of the heat exchange tube located between the upper tube sheet and the lower tube sheet. The upper ends of the jacket tubes are communicated with the inner space of the jacket tubes through a first pipeline, and the lower ends of the jacket tubes are communicated with the inner space of the jacket tubes through a second pipeline. Along the flow direction of the medium in the jacket tube, a medium inlet pipe passing through the heat exchanger main body is provided on the first jacket tube, and a medium outlet pipe passing through the heat exchanger main body is provided on the last jacket tube. The medium inlet pipe is located above the outlet header, and the medium outlet pipe is located below the inlet header.

[0007] A spiral guide plate is provided in the jacket tube, and the spiral guide plate is spirally arranged along the length direction of the heat exchange tube outside the heat exchange tube.

[0008] The diameter range of the heat exchange tube is 400mm to 700mm.

[0009] The flue gas inlet and the flue gas outlet are respectively located at opposite sides of the heat exchanger main body.

[0010] A baffle with an angle less than 90° with the flue gas outlet is provided above the flue gas outlet.

[0011] The upper end opening of the heat exchange tube adopts a spiral rising structure. In the same heat exchange tube, the part of the upper end opening close to the flue gas inlet is lower than the part far from the flue gas inlet.

[0012] In the direction gradually away from the flue gas inlet, the positions of the upper ends of the heat exchange tubes increase in sequence.

[0013] On the inner wall of the heat exchange tube, there are guide ridge plates. One end of the guide ridge plate is high and the other end is low, and they are spirally distributed. The spiral distribution direction of the guide ridge plates is the same as the spiral direction at the upper end opening of the heat exchange tube.

[0014] On the inner side of the top surface of the inlet header, baffle plates are respectively provided above the lowest position of the upper end opening of each heat exchange tube. The baffle plates incline downward to guide the flue gas into the upper end opening of the heat exchange tube.

[0015] The beneficial effects of the present invention are as follows: Since a dust cleaning mechanism is provided outside the heat exchanger main body, when salts and dust scale on the inner wall of the heat exchange tube, the sealing cover on the dust cleaning opening above the corresponding pipeline is opened, and the dust cleaning mechanism is used to perform on-line dust cleaning inside the heat exchange tube. Before dust cleaning, the telescopic rod is adjusted to an appropriate length so that the rotating rod is located directly above the heat exchange tube to be dust cleaned, and the sealing cover directly above the heat exchange tube is quickly opened to reduce flue gas leakage. The lifting motor drives the lifting rod to quickly descend, driving the rotating rod to descend so that the dust cleaning brush enters the pipe orifice of the heat exchange tube. The rotating motor drives the rotating rod to rotate to drive the dust cleaning brush to rotate, realizing the removal of ash scale and salts on the inner wall of the heat exchange tube. At the same time, the lifting motor drives the lifting rod to descend, and the dust cleaning brush cleans the inner wall of the heat exchange tube from top to bottom. The cleaned ash residues are discharged from the slag discharge port at the bottom of the outlet header. When the present invention performs dust cleaning, it does not need to stop the machine, realizing on-line dust cleaning operation. After dust cleaning, the ash residues are discharged from the bottom slag discharge port, and the flue gas is discharged from the side. Therefore, the dust content in the flue gas can be reduced, and the influence on subsequent catalytic equipment can be reduced. Using the present invention makes the recovery of high-salt furnace gas with dust safer and does not affect downstream equipment, enabling the system to operate continuously and stably.

[0016] When the high-temperature flue gas desalination and dust removal heat energy recovery device of the present invention is in use, it is placed between the waste acid incineration cracking furnace and the waste heat boiler, so that the high-salt flue gas is reduced to 800 °C before entering the boiler, enabling the early precipitation of high-salt components and the precipitation and removal of solid dust particles in the flue gas, solving the problem of serious scale and ash accumulation on the heat pipes of the boiler in the high-salt high-temperature flue gas condition of the existing chemical device, and at the same time efficiently utilizing the heat energy of this section of temperature reduction.

[0017] Preferably, the flue gas enters the inlet header from the left side, then enters the heat exchange tube, transfers heat to the cooling medium, and then enters the outlet flue gas box and is discharged from the right side of the outlet flue gas box; the cooling medium enters the jacket outside the heat exchange tube from the right side of the heat exchanger main body from bottom to top, absorbs the heat in the flue gas and is discharged from the left side of the heat exchanger main body. When the cooling medium flows, the spiral guide plate guides the cooling medium upward, accelerating the flow of the cooling medium and improving the heat exchange efficiency.

[0018] Preferably, the heat exchange tubes have a large diameter of 400 mm to 700 mm, facilitating the entry of the soot brush for soot cleaning.

[0019] Preferably, the heights of the inlet ends of the heat exchange tubes are arranged in a gradually increasing manner along the air inlet direction. Multiple groups of flow guiding ridge plates are provided inside the heat exchange tubes. The spiral inclination of the ridge plates is consistent with the spiral inclination angle of the tube orifice. By using the inlet of the spiral structure and the flow guiding ridge plates, the flue gas entering the heat exchange tubes forms a downward swirling air flow direction, achieving the separation and removal of solid particles and salt components in the flue gas and meeting high-performance heat exchange.

[0020] Preferably, a baffle plate is arranged above the heat exchange tubes to deflect and guide the flue gas, enabling the flue gas to quickly enter the heat exchange tubes.

[0021] Preferably, a baffle is arranged above the flue gas outlet of the outlet header box, which can reduce the discharge of dust from the flue gas outlet. Description of the Drawings

[0022] Figure 1 is a schematic diagram of a high-temperature flue gas desalination and dust removal heat energy recovery device according to an embodiment of the present invention;

[0023] Figure 2 is a partial enlarged view of FIG. 1;

[0024] In the figure: 1 - outlet header box, 1.1 - flue gas outlet, 2 - lower tube sheet, 3 - heat exchanger main body, 4 - heat exchange tubes, 5 - flow guiding ridge plates, 6 - spiral flow guiding plates, 7 - jacket pipe, 7.1 - first pipe, 7.2 - second pipe, 7.3 - medium inlet pipe, 7.4 - medium outlet pipe, 8 - upper tube sheet, 9 - inlet header box, 9.1 - flue gas inlet, 10 - soot cleaning port, 11 - baffle plate, 12 - soot cleaning mechanism, 12.1 - lifting rod, 12.2 - rotating rod, 12.3 - telescopic rod, 12.4 - lifting motor, 12.5 - rotating motor, 12.6 - soot brush, 12.7 - guide sleeve, 13 - baffle, 14 - slag discharge port. Detailed Embodiments

[0025] The present invention will be described in detail below with reference to the drawings and specific embodiments.

[0026] A high-temperature flue gas desalination and dust removal heat energy recovery device according to an embodiment of the present invention is as Figure 1As shown in the figure, it includes a heat exchanger body 3 with heat exchange tubes 4. A heat insulation layer is provided outside the heat exchanger body 3. The heat exchanger body 3 adopts a vertical structure. The heat exchange tubes 4 are vertically installed in the heat exchanger body 3. An upper tube sheet 8 is provided in the upper part of the heat exchanger body 3, and a lower tube sheet 2 is provided in the lower part. Above the upper tube sheet 8 is an inlet header 9, and below the lower tube sheet 2 is an outlet header 1. A flue gas inlet 9.1 is provided on the side of the inlet header 9, and a flue gas outlet 1.1 is provided on the side of the outlet header 1. The upper end of the heat exchange tube 4 passes through the upper tube sheet 8 and leads into the inlet header 9, and the lower end of the heat exchange tube 4 passes through the lower tube sheet 2 and is communicated with the outlet header 1. The bottom of the outlet header 1 is a tapered structure with a larger upper part and a smaller lower part, and a slag discharge port 14 is provided at the bottom end of the tapered structure.

[0027] A dust cleaning mechanism 12 for cleaning the inside of the heat exchange tubes 4 is provided outside the heat exchanger body 3. The dust cleaning mechanism 12 includes a lifting rod 12.1 and a rotating rod 12.2 that are vertically and parallelly arranged. A horizontally arranged telescopic rod 12.3 is connected between the upper end of the lifting rod 12.1 and the upper end of the rotating rod 12.2. One end of the telescopic rod 12.3 is fixedly connected to the lifting rod 12.1, and a guide sleeve 12.7 through which the rotating rod passes is provided at the other end of the telescopic rod 12.3. The rotating rod 12.2 is rotationally matched with the guide sleeve 12.7. A lifting motor 12.4 for driving the lifting rod 12.1 to move up and down is connected to the lifting rod 12.1, and a rotating motor 12.5 for driving the rotating rod 12.5 to rotate is connected to the upper end of the rotating rod 12.5. A dust cleaning brush 12.6 for contacting the inner peripheral surface of the heat exchange tube 4 is provided at the lower end of the rotating rod 12.5.

[0028] A dust cleaning port 10 for the dust cleaning brush 12.6 to enter the heat exchange tube downward is provided at the top of the inlet header 9. The number of the dust cleaning ports 10 is equal to the number of the heat exchange tubes 4. Each dust cleaning port 10 is located above each heat exchange tube 4, and a sealing cover is provided on each dust cleaning port 10.

[0029] A jacket tube 7 is hermetically sleeved on the outer periphery of the part of the heat exchange tube 4 between the upper tube sheet 8 and the lower tube sheet 2. The upper ends of the jacket tubes 7 are communicated with the internal space of the jacket tubes 7 through a first pipeline 7.1, and the lower ends of the jacket tubes 7 are communicated with the internal space of the jacket tubes 7 through a second pipeline 7.2. Along the flow direction of the medium in the jacket tube 7, a medium inlet pipe 7.3 passing through the heat exchanger body 3 is provided on the first jacket tube 7, and a medium outlet pipe 7.4 passing through the heat exchanger body 3 is provided on the last jacket tube 3. The medium inlet pipe 7.3 is located above the outlet header 1, and the medium outlet pipe 7.4 is located below the inlet header 9.

[0030] A spiral guide plate 6 is provided in the jacket tube 7. The spiral guide plate 6 is spirally arranged along the length direction of the heat exchange tube 4 outside the heat exchange tube 4. The spiral guide plate conducts the cooling medium upward, accelerates the flow of the cooling medium, and improves the heat exchange efficiency.

[0031] The flue gas inlet 9.1 and the flue gas outlet 1.1 are respectively located at opposite sides of the heat exchanger main body 3; the diameter range of the heat exchange tubes 4 is 400 mm to 700 mm. Above the flue gas outlet 1.1, there is a baffle 13 with an angle less than 90° with the flue gas outlet 1.1.

[0032] As Figure 2 shown, in this embodiment, the upper end opening of the heat exchange tube 4 adopts a spiral rising structure. In the same heat exchange tube 4, the part of the upper end opening close to the flue gas inlet is lower than the part far from the flue gas inlet. In the direction gradually away from the flue gas inlet 9.1, the positions of the upper ends of the heat exchange tubes 4 increase in sequence.

[0033] On the inner wall of the heat exchange tube 4, there are diversion ridge plates 5. One end of the diversion ridge plate 5 is high and the other end is low and it is spirally distributed. The spiral direction of the diversion ridge plate 5 is the same as the spiral direction of the upper end opening of the heat exchange tube 4.

[0034] On the inner side of the top surface of the inlet header 9, there are baffle plates 11 respectively above the lowest position of the upper end opening of each heat exchange tube 4. The baffle plates 11 are inclined downward to guide the flue gas into the upper end opening of the heat exchange tube 4.

[0035] The heat exchanger main body of the present invention uses corrosion-resistant and high-temperature-resistant stainless steel S31008 as the main material and adopts a vertical structure with the flue gas side entering. As Figure 1 shown, the flue gas enters the inlet header from the left side, then enters the heat exchange tubes, transfers heat to the cooling medium, enters the outlet flue gas box, and is discharged from the right side of the outlet flue gas box; the cooling medium enters the jacket outside the heat exchange tubes from the bottom up on the right side of the heat exchanger main body, absorbs the heat in the flue gas, and is discharged from the left side of the heat exchanger main body. In this embodiment, components operating at high temperatures such as the heat exchange tubes and the jacket are all made of stainless steel S3100, and an outer thermal insulation layer is provided outside the heat exchanger main body, the inlet header, the outlet header, the flue gas inlet, and the flue gas outlet.

[0036] In this embodiment, the heat exchange tubes adopt large-diameter sizes. The inlet ends of each heat exchange tube adopt a semi-circular spiral port design. The heights of the inlet ends of the heat exchange tubes are arranged in a gradually increasing manner along the air inlet direction. There are multiple groups of diversion ridge plates inside the heat exchange tubes. The spiral inclination of the ridge plates is the same as the spiral inclination of the tube orifice. The height range of the ridge plates is 10 mm to 30 mm. By using the spiral structure of the inlet and the diversion ridge plates, the flue gas entering the heat exchange tubes forms a downward swirling air flow direction, achieving the separation and removal of solid particles and salt components in the flue gas and meeting high heat transfer performance.

[0037] When scale forms on the inner wall of the heat exchange tubes due to salts and dust, the sealing cover on the dust cleaning port above the corresponding pipeline can be opened, and the dust cleaning mechanism is used to perform on-line dust cleaning inside the heat exchange tubes. Before dust cleaning, the telescopic rod is adjusted to an appropriate length so that the rotating rod is directly above the heat exchange tube to be dust cleaned. The sealing cover directly above the heat exchange tube is quickly opened, and the lifting motor drives the lifting rod to quickly descend, driving the rotating rod to descend so that the dust cleaning brush enters the pipe orifice of the heat exchange tube. The rotating motor drives the rotating rod to rotate to drive the dust cleaning brush to rotate, realizing the removal of scale and salts on the inner wall of the heat exchange tube. At the same time, the lifting motor drives the lifting rod to descend, and the dust cleaning brush cleans the inner wall of the heat exchange tube from top to bottom. The ash residues after cleaning are discharged from the slag discharge port at the bottom of the outlet header box. When the present invention performs dust cleaning, it does not need to stop the machine, realizing on-line dust cleaning operation. After dust cleaning, the ash residues are discharged from the bottom slag discharge port, and the flue gas is discharged from the side. Therefore, the dust content in the flue gas can be reduced, and the influence on subsequent catalytic equipment can be reduced.

[0038] In the drawings of this embodiment, only three heat exchange tubes are used as an illustration. In actual use, the number of heat exchange tubes can be flexibly set according to actual needs. A single heat exchange tube can be used, or multiple rows and multiple columns of juxtaposed heat exchange tubes can be used.

[0039] What is described in the above embodiments and the specification only illustrates the structural principle of the present invention. Without departing from the concept of the present invention, the present invention will have various changes, and these changes and improvements all fall within the scope of the claims of the present invention to be protected.

Claims

1. High-temperature flue gas desalination and dust removal heat energy recovery device, which includes a heat exchanger main body with heat exchange tubes, characterized in that: The heat exchanger body adopts a vertical structure, and the heat exchange tubes are installed vertically in the heat exchanger body. An upper tube sheet is provided in the upper part of the heat exchanger body, and a lower tube sheet is provided in the lower part. Above the upper tube sheet is an inlet header, and below the lower tube sheet is an outlet header. A flue gas inlet is provided on the side of the inlet header, and a flue gas outlet is provided on the side of the outlet header. The upper ends of the heat exchange tubes pass through the upper tube sheet and lead into the inlet header, and the lower ends of the heat exchange tubes pass through the lower tube sheet and communicate with the outlet header; the bottom of the outlet header is a conical structure with a larger upper part and a smaller lower part, and a slag discharge port is provided at the lowest end of the conical structure; A dust cleaning mechanism for cleaning the inside of the heat exchange tubes is provided outside the heat exchanger body. The dust cleaning mechanism includes a lifting rod and a rotating rod that are vertically and parallelly arranged. A telescopic rod is horizontally connected between the upper ends of the lifting rod and the rotating rod. One end of the telescopic rod is fixedly connected to the lifting rod, and the other end of the telescopic rod is provided with a guide sleeve for the rotating rod to pass through. The rotating rod is rotationally matched with the guide sleeve. A lifting motor for driving the lifting rod to move up and down is connected to the lifting rod, and a rotating motor for driving the rotating rod to rotate is connected to the upper end of the rotating rod. A dust cleaning brush for contacting the inner peripheral surface of the heat exchange tube is provided at the lower end of the rotating rod; A dust cleaning port for the dust cleaning brush to enter the heat exchange tube downward is provided at the top of the inlet header. The number of dust cleaning ports is equal to the number of heat exchange tubes. Each dust cleaning port is located above each heat exchange tube, and a sealing cover is provided on each dust cleaning port respectively.

2. The high-temperature flue gas desalination, dust removal and heat energy recovery device according to claim 1, wherein: A jacket tube is hermetically sleeved on the outer periphery of the part of the heat exchange tube between the upper tube sheet and the lower tube sheet. The upper ends of the jacket tubes are connected through a first pipeline to communicate the internal spaces of the jacket tubes, and the lower ends of the jacket tubes are connected through a second pipeline to communicate the internal spaces of the jacket tubes. Along the flow direction of the medium in the jacket tube, a medium inlet pipe passing through the heat exchanger body is provided on the first jacket tube, and a medium outlet pipe passing through the heat exchanger body is provided on the last jacket tube. The medium inlet pipe is located above the outlet header, and the medium outlet pipe is located below the inlet header.

3. The high-temperature flue gas desalination, dust removal and heat energy recovery device according to claim 2, characterized in that: A spiral guide plate is provided in the jacket tube, and the spiral guide plate is spirally arranged along the length direction of the heat exchange tube outside the heat exchange tube.

4. The high-temperature flue gas desalination, dust removal and heat energy recovery device according to claim 1, characterized in that: The diameter range of the heat exchange tube is 400mm - 700mm.

5. The high-temperature flue gas desalination, dust removal and heat energy recovery device according to claim 1, wherein: The flue gas inlet and the flue gas outlet are respectively located at opposite sides of the heat exchanger body.

6. The high-temperature flue gas desalination, dust removal and heat energy recovery device according to claim 1, characterized in that: A baffle is provided above the flue gas outlet at an angle less than 90° with the flue gas outlet.

7. The high-temperature flue gas desalination, dust removal and heat energy recovery device according to claim 1, characterized in that: The upper end opening of the heat exchange tube adopts a spiral ascending structure. In the same heat exchange tube, the part of the upper end opening close to the flue gas inlet is lower than the part far from the flue gas inlet.

8. The high-temperature flue gas desalination and dust removal heat energy recovery device according to claim 7, characterized in that: In the direction gradually away from the flue gas inlet, the positions of the upper ends of the heat exchange tubes increase in sequence.

9. The high-temperature flue gas desalination, dust removal and heat energy recovery device according to claim 7, characterized in that: Flow guiding ridge plates are provided on the inner wall of the heat exchange tube. One end of the flow guiding ridge plate is high and the other end is low and is spirally distributed. The spiral distribution direction of the flow guiding ridge plates is the same as the spiral direction of the upper end opening of the heat exchange tube.

10. The high-temperature flue gas desalination, dust removal and heat energy recovery device according to claim 7, characterized in that: Deflector plates are respectively provided on the inner side of the top surface of the inlet header above the lowest position of the upper end opening of each heat exchange tube. The deflector plates are inclined downward to guide the flue gas into the upper end opening of the heat exchange tube.

Images