Coal economizer flue system

Abstract

The application discloses a coal economizer flue system, which comprises a coal economizer shell, a high-temperature flue gas introduction pipe is integrally connected to one side of the lower end of the coal economizer shell, and a flue gas discharge port is arranged at the top end of the coal economizer shell; the coal economizer shell comprises a heat exchange cavity and a heat exchange pipe capable of conveying liquid water; the heat exchange pipe is composed of a plurality of straight pipe sections and elbows used for connecting the straight pipe sections in series; all the straight pipe sections of the heat exchange pipe are horizontally parallel to the heat exchange cavity, and there is a flue gas gap between any two adjacent straight pipe sections of the heat exchange pipe; the head and tail of the heat exchange pipe are respectively a water inlet end and a water outlet end; the coal economizer shell comprises a vertical a fixed partition plate, an a lifting partition plate, a b fixed partition plate and a b lifting partition plate from left to right, and automatic conversion between a low air resistance state and a high flue gas stroke state is realized.

Description

Technical Field

[0001] This invention belongs to the field of economizers. Background Technology

[0002] Conventional economizers typically use fixed series or parallel flue gas passages, and once the design is finalized, the flow path cannot be adjusted during operation. When the boiler load is high and the flue gas flow rate is large, fixed series flue gas passages can lead to a significant increase in flue gas flow resistance, resulting in increased furnace back pressure, increased induced draft fan power consumption, and even limited combustion intensity. Conversely, when the boiler is operating at low load or during start-up and shutdown, and the flue gas flow rate is small, fixed parallel flue gas passages, while having lower resistance, suffer from insufficient contact time between the flue gas and the heat exchange tube bundle due to the short flue gas path. As a result, a large amount of waste heat is not fully recovered and is lost through the exhaust port, leading to higher exhaust gas temperature and reduced thermal efficiency. Summary of the Invention

[0003] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the present invention provides an economizer flue system and working method to realize the automatic switching between low gas resistance state and high flue gas stroke state.

[0004] Technical Solution: To achieve the above objectives, the present invention provides an economizer flue system, comprising an economizer shell, a high-temperature flue gas inlet pipe integrally connected to one side of the lower end of the economizer shell, and a flue gas outlet at the top of the economizer shell; the economizer shell includes a heat exchange chamber and a heat exchange tube capable of transmitting liquid water; the heat exchange tube is composed of multiple straight pipe sections and elbows connecting the ends of the straight pipe sections; all straight pipe sections of the heat exchange tube are transversely parallel to the heat exchange chamber, and a flue gas gap exists between any two adjacent straight sections of the heat exchange tube; the beginning and end of the heat exchange tube are the water inlet and water outlet, respectively; the economizer shell includes, from left to right, vertical a fixed baffle, a lifting baffle, b fixed baffle, and b lifting baffle.

[0005] Furthermore, the elbows are distributed on the outside of the economizer shell.

[0006] Furthermore, the economizer shell includes a bottom wall and a top wall. The top wall includes a central flat top wall and two symmetrical left and right inclined top walls. A rectangular exhaust port is cut out on the central flat top wall.

[0007] Furthermore, a first flue gas heat exchange channel is formed between the right shell wall of the economizer shell and the b lifting baffle; a second flue gas heat exchange channel is formed between the b lifting baffle and the b fixed baffle; a third flue gas heat exchange channel is formed between the b fixed baffle and the a lifting baffle; a fourth flue gas heat exchange channel is formed between the a lifting baffle and the a fixed baffle; and a fifth flue gas heat exchange channel is formed between the a fixed baffle and the left shell wall of the economizer shell.

[0008] Furthermore, each of the first, second, third, fourth, and fifth flue gas heat exchange channels has horizontally passing through parallel and evenly distributed straight heat exchange tube sections.

[0009] Furthermore, the upper end of fixed partition a is hinged to gravity swing plate a via hinge a, and the upper inner side of the right shell wall is hinged to gravity swing plate b via hinge b; gravity swing plate a and gravity swing plate b are symmetrical about the center line of fixed partition b; a horizontal support platform is integrally connected to the upper end of fixed partition b; the upper section of lifting partition a near the top is the upper ventilation section of lifting partition a; the upper section of lifting partition b near the top is the upper ventilation section of lifting partition b; ventilation holes are evenly perforated on the upper ventilation sections of lifting partition a and lifting partition b, so that flue gas can pass smoothly through the upper ventilation sections of lifting partition a and lifting partition b; rollers a and b are rotatably mounted on the upper ends of the upper ventilation sections of lifting partition a and lifting partition b via bearings; rollers a and b are tangentially rolled with the lower surfaces of gravity swing plate a and gravity swing plate b, respectively.

[0010] Furthermore, this includes two states: low air resistance and high flue gas travel. In the "low air resistance state": the lower ends of fixed baffle a, lifting baffle a, fixed baffle b, and lifting baffle b all form a gap with the bottom wall of the shell, thus forming a section of air pressure chamber on the upper side of the bottom wall of the shell. One side of the air pressure chamber is connected to the high-temperature flue gas inlet pipe. Gravity swing plate a is tilted under the support of roller a, and the upper end of gravity swing plate a is limited to contact the center position of the lower surface of the central flat top wall. The upper contour of gravity swing plate a divides the exhaust port on the central flat top wall into two halves. At the same time, gravity swing plate b is tilted under the support of roller b, and the upper end of gravity swing plate b is limited to contact the right edge of the lower surface of the central flat top wall. The upper contour of gravity swing plate a divides the exhaust port on the central flat top wall into two halves. At this time, the left and right symmetrical gravity swing plates a and b form an equal shape that is narrower at the top and wider at the bottom. The main exhaust chamber is shaped like a waist trapezoid; both the upper ventilation section of the lifting baffle (a) and the upper ventilation section of the lifting baffle (b) are vertically positioned within the main exhaust chamber; the upper end of the main exhaust chamber is connected to the outside through the right half of the exhaust port; the upper ends of the first, second, third, and fourth flue gas heat exchange channels are connected to the lower end of the main exhaust chamber; an upward-sloping secondary exhaust chamber is formed between the gravity swing plate (a) and the left inclined top wall, and the upper end of the secondary exhaust chamber is connected to the outside through the left half of the exhaust port; the upper end of the fifth flue gas heat exchange channel is connected to the lower end of the secondary exhaust chamber; the lower ends of the first, second, third, fourth, and fifth flue gas heat exchange channels are connected to the ventilation pressure chamber; based on the "low air resistance state," when the lifting baffle (a) and the lifting baffle (b) descend to their lower ends and reach the limit contact with the bottom wall of the shell, they transition to the "high flue gas stroke state."

[0011] Under the "high flue gas travel state":

[0012] The lower ends of both lifting baffles a and b descend to the limit contact bottom wall of the housing. The originally tilted gravity swing plates a and b, losing the support of rollers a and b, swing downwards to a horizontal position under gravity. The ends of the horizontally positioned gravity swing plates a and b are supported by the left and right ends of the horizontal support platform, respectively. In this state, the main exhaust chamber and auxiliary exhaust chamber, originally in a "low air resistance state," merge into a single exhaust chamber. Simultaneously, the upper ends of the first and second flue gas heat exchange channels are separated from the single exhaust chamber by the horizontal gravity swing plate b; the upper ends of the third and fourth flue gas heat exchange channels are separated from the single exhaust chamber by the horizontal gravity swing plate a. The lower ends of lifting baffles a and b divide the original "low air resistance state" air pressure chamber into three compartments from left to right: the first compartment, the second compartment, and the third compartment. The high-temperature flue gas inlet pipe connects to the lower end of the first flue gas heat exchange channel through the third compartment. The upper left side of the first flue gas heat exchange channel connects to the upper right side of the second flue gas heat exchange channel through the upper venting section of lifting baffle b. The lower end of the second flue gas heat exchange channel connects to the lower end of the third flue gas heat exchange channel through the second compartment. The upper left side of the third flue gas heat exchange channel connects to the upper right side of the fourth flue gas heat exchange channel through the upper venting section of lifting baffle a. The lower end of the fourth flue gas heat exchange channel connects to the lower end of the fifth flue gas heat exchange channel through the first compartment. The upper end of the fifth flue gas heat exchange channel connects to a single exhaust chamber.

[0013] Beneficial effects: By utilizing the linkage between the lifting baffle and the gravity swing plate, the present invention achieves automatic switching between low air resistance state and high flue gas stroke state without adding external valves and complex control mechanisms.

[0014] When the flue gas flow rate is high, the lifting baffle is in a high position, and the bottom of all channels are connected in parallel through the air pressure chamber. The flue gas flows through five channels at the same time and then merges into the exhaust port. The total resistance of the flow channel is greatly reduced, ensuring smooth exhaust and stable furnace pressure under high load conditions.

[0015] When the flue gas flow rate is low, the lifting device drives the lifting baffle to descend until it contacts the bottom wall of the shell. After the gravity swing plate loses the support of the rollers, it automatically falls to the horizontal position, thereby merging the top space into a single flue gas chamber and dividing the bottom air pressure chamber into three compartments. The flue gas flows through five channels in sequence to form a serpentine series stroke that is five times longer than that in the low air resistance state, which greatly extends the contact time between the flue gas and the heat exchange tube bundle and improves the heat recovery rate under low load. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the economizer as a whole.

[0017] Figure 2 This is a partial schematic diagram of the device from another perspective;

[0018] Figure 3 This is a cross-sectional view under "low air resistance" conditions;

[0019] Figure 4 This is a cross-sectional view under the "high flue gas travel condition";

[0020] Figure 5 for Figure 4 A three-dimensional image;

[0021] Figure 6 for" Figure 4 "A schematic diagram with the heat exchanger tubes removed;" Detailed Implementation

[0022] The invention will now be further described with reference to the accompanying drawings.

[0023] like Figures 1 to 4 An economizer flue system is shown, comprising an economizer shell 1, a high-temperature flue gas inlet pipe 9 integrally connected to one side of the lower end of the economizer shell 1, and a flue gas outlet 3 at the top of the economizer shell 1; the economizer shell 1 includes a heat exchange chamber 17 and a heat exchange tube 2 capable of transmitting liquid water; the heat exchange tube 2 is composed of multiple straight pipe sections and elbows 2.1 for connecting the straight pipe sections end to end, forming a reciprocating bending structure; each elbow 2.1 is distributed on the outside of the economizer shell 1, all straight pipe sections of the heat exchange tube 2 are transversely parallel to the heat exchange chamber 17, and there is a flue gas gap between any two adjacent straight sections of the heat exchange tube 2; the beginning and end of the heat exchange tube 2 are a water inlet 71 and a water outlet 72, respectively.

[0024] The economizer shell 1 includes a bottom wall 16 and a top wall. The top wall includes a central flat top wall 4 and two symmetrical left and right inclined top walls 23.1 and 23.2. A rectangular exhaust port 3 is hollowed out on the central flat top wall 4. Inside the economizer shell 1, from left to right, there are vertical a fixed partition 21, a lifting partition 19, b fixed partition 20 and b lifting partition 18.

[0025] A first flue gas heat exchange channel 17a is formed between the right shell wall 1.2 of the economizer shell 1 and the b lifting partition 18; a second flue gas heat exchange channel 17b is formed between the b lifting partition 18 and the b fixed partition 20; a third flue gas heat exchange channel 17c is formed between the b fixed partition 20 and the a lifting partition 19; a fourth flue gas heat exchange channel 17d is formed between the a lifting partition 19 and the a fixed partition 21; and a fifth flue gas heat exchange channel 17e is formed between the a fixed partition 21 and the left shell wall 1.1 of the economizer shell 1.

[0026] The active lifting device on the inner wall of the economizer shell 1 can drive the lifting baffles 19 and 18 to perform active lifting movements. The active lifting device can be either an electric push rod or a screw jack, and the power transmission and lifting linkage with the internal baffles are realized through the sealing components on the shell. The lifting device can be connected to the boiler DCS control system, and automatically determine the current flue gas flow status based on the real-time signal from the flow meter or differential pressure transmitter installed at the high-temperature flue gas inlet pipe 9, and execute the corresponding lifting action.

[0027] Each of the first flue gas heat exchange channel 17a, the second flue gas heat exchange channel 17b, the third flue gas heat exchange channel 17c, the fourth flue gas heat exchange channel 17d, and the fifth flue gas heat exchange channel 17e has a horizontally passing section of a parallel and evenly distributed heat exchange tube 2 straight pipe.

[0028] The upper end of fixed partition 21 is hinged to gravity swing plate 10 via hinge 12, and the inner side of the upper end of right shell wall 1.2 is hinged to gravity swing plate 11 via hinge 13. Gravity swing plate 10 and gravity swing plate 11 are symmetrical about the center line of fixed partition 20. Gravity swing plate 10 and gravity swing plate 11 are made of stainless steel or cast iron, and their own weight is sufficient to overcome the buoyancy of flue gas and flow disturbance.

[0029] The upper end of the fixed partition 20 is integrally connected to a horizontal support platform 6; the upper section of the lifting partition 19 is the upper ventilation section 19.2; the upper section of the lifting partition 18 is the upper ventilation section 18.2; the upper ventilation sections 19.2 and 18.2 are evenly perforated with ventilation holes, so that the upper ventilation sections 19.2 and 18.2 can smoothly allow flue gas to pass through.

[0030] The upper ends of the upper ventilation section 19.2 of the lifting partition a and the upper ventilation section 18.2 of the lifting partition b are respectively rotatably mounted with roller a 14 and roller b 15 via bearings; roller a 14 and roller b 15 roll tangentially with the lower surfaces of gravity pendulum a 10 and gravity pendulum b 11 respectively; roller a 14 and roller b 15 are made of heat-resistant ceramic rollers. When the lifting partition rises, the rollers push the gravity pendulum upwards, causing it to rotate upwards around the hinge.

[0031] The economizer has two states: low gas resistance and high flue gas stroke. This allows the same economizer to dynamically adjust the internal flue gas flow channel structure according to changes in boiler load and flue gas flow. This ensures smooth flue gas exhaust under high load conditions, preventing excessive furnace back pressure from affecting combustion efficiency, while also ensuring that the flue gas can fully release heat under low load conditions, thereby improving feedwater temperature and overall boiler thermal efficiency.

[0032] When the flow rate of the high-temperature flue gas inlet pipe 9 is too high, reducing the exhaust resistance of the high-temperature flue gas inlet pipe 9 takes precedence over heat utilization, requiring the economizer to enter a "low air resistance state". In the "low air resistance state", the lower ends of a fixed baffle 21, a lifting baffle 19, b fixed baffle 20, and b lifting baffle 18 are all spaced from the bottom wall 16 of the shell, thereby forming a section of air pressure chamber 7 on the upper side of the bottom wall 16 of the shell. One side of the air pressure chamber 7 is connected to the high-temperature flue gas inlet pipe 9; a gravity swing plate 10 is tilted under the support of a roller 14, and the upper end of a gravity swing plate 10 is limited. The upper contour of gravity swing plate 10 divides the smoke exhaust port 3 on the central flat top wall 4 into two halves, with the lower surface of the central flat top wall 4 in the center. Simultaneously, gravity swing plate 11, supported by roller 15, is tilted, with its upper end positioned to contact the right edge of the lower surface of the central flat top wall 4. The upper contour of gravity swing plate 10 divides the smoke exhaust port 3 on the central flat top wall 4 into two halves. At this point, the symmetrical gravity swing plate 10 and gravity swing plate 11 form a main smoke exhaust chamber 5b, which is narrower at the top and wider at the bottom than the upper surface of the central flat top wall 4. The upper ventilation section 19 of the lifting partition... Both the upper ventilated sections 18.2 and 19.2 of the lifting partition are vertically positioned within the main exhaust chamber 5b. The upper ventilated sections 18.2 and 19.2 of the lifting partition serve as ventilated structures and do not provide substantial separation or gas isolation for the main exhaust chamber 5b. The upper end of the main exhaust chamber 5b is connected to the outside via the right half of the exhaust port 3. The upper ends of the first flue gas heat exchange channel 17a, the second flue gas heat exchange channel 17b, the third flue gas heat exchange channel 17c, and the fourth flue gas heat exchange channel 17d are connected to the lower end of the main exhaust chamber 5b. The gravity swing plate 10 is connected to the left inclined top wall 23. A secondary flue gas chamber 5a is formed at an upward angle between the two sides. The upper end of the secondary flue gas chamber 5a is connected to the outside through the left half of the flue gas outlet 3. The upper end of the fifth flue gas heat exchange channel 17e is connected to the lower end of the secondary flue gas chamber 5a. The lower ends of the first flue gas heat exchange channel 17a, the second flue gas heat exchange channel 17b, the third flue gas heat exchange channel 17c, the fourth flue gas heat exchange channel 17d, and the fifth flue gas heat exchange channel 17e are connected to the ventilation pressure chamber 7. Under this "low air resistance state", all flue gas heat exchange channels form parallel air intake at the bottom through the ventilation pressure chamber 7, and converge into the main flue gas chamber 5b and the secondary flue gas chamber 5a respectively at the top. This parallel flow channel structure makes the total resistance coefficient of flue gas flow only about one-fifth of that of a single long-stroke flow channel, thereby effectively reducing the pressure drop on the economizer side when the flue gas flow is large, and avoiding a sharp increase in boiler furnace positive pressure or induced draft fan power consumption due to poor flue gas exhaust.

[0033] Flue gas path and principle under "low air resistance":

[0034] High-flow-rate flue gas from the high-temperature flue gas inlet pipe 9 is continuously introduced into the pressure chamber 7, thereby creating a pressure chamber 7 to concentrate the high-temperature flue gas. The high-temperature flue gas entering the pressure chamber 7 is then simultaneously diverted upwards into the first flue gas heat exchange channel 17a, the second flue gas heat exchange channel 17b, the third flue gas heat exchange channel 17c, the fourth flue gas heat exchange channel 17d, and the fifth flue gas heat exchange channel 17e. The high-temperature flue gas flows upwards in parallel through these channels, and then... The flue gas at the upper end of flue 17d is collected in the main exhaust chamber 5b and discharged to the outside through the right half of the exhaust port 3, while the flue gas at the upper end of the fifth flue gas heat exchange channel 17e is discharged to the outside through the auxiliary exhaust chamber 5a and the left half of the exhaust port 3. In this state, the flue gas flows in parallel through the first flue gas heat exchange channel 17a, the second flue gas heat exchange channel 17b, the third flue gas heat exchange channel 17c, the fourth flue gas heat exchange channel 17d, and the fifth flue gas heat exchange channel 17e, which significantly reduces the flue gas flow resistance. At the same time, although the shortened flue gas flow path reduces the heat exchange time per flow through the heat exchange tubes, the increased flue gas velocity and Reynolds number at high flow rates also increase the external convective heat transfer coefficient, which to some extent compensates for the heat transfer loss caused by the shortened flow path. The low gas resistance state ensures the safe and stable operation of the boiler during high load or start-up and shutdown phases, preventing the forced reduction of combustion intensity or the triggering of interlocking protection actions due to excessive economizer resistance.

[0035] When the high-temperature flue gas flow rate in the high-temperature flue gas inlet pipe 9 is low, the priority of improving the heat utilization rate of the high-temperature flue gas is higher than the priority of exhaust resistance. It is necessary to change from "low air resistance state" to "high flue gas stroke state". The process of changing from "low air resistance state" to "high flue gas stroke state" is achieved by actively controlling the lifting device to lower the a lifting baffle 19 and b lifting baffle 18 until they both fall to the limit contact with the bottom wall 16 of the housing. During the switching process, the lifting device drives the a lifting baffle 19 and b lifting baffle 18 to move downward synchronously. After the lower edge of the lifting baffle contacts the bottom wall 16 of the housing, the upper surface of the bottom wall 16 of the housing has a pre-processed sealing groove or flexible sealing strip that matches the lower edge of the baffle. This can further ensure the flue gas sealing between the compartments and prevent the flue gas from leaking in a non-designed path.

[0036] The economizer is in the "high flue gas stroke state":

[0037] The lower ends of lifting baffle 19 and lifting baffle 18 both descend to the limit contact bottom wall 16 of the housing. The originally tilted gravity swing plate 10 and gravity swing plate 11 lose the support of roller 14 and roller 15 and swing downward to the horizontal under the action of gravity. The ends of the horizontal gravity swing plate 10 and gravity swing plate 11 are supported by the left and right ends of the horizontal support platform 6 respectively. In this state, the main smoke chamber 5b and the auxiliary smoke chamber 5a, which were originally in the "low air resistance state", merge into a single smoke chamber 5. Meanwhile, the upper ends of the first flue gas heat exchange channel 17a and the second flue gas heat exchange channel 17b are separated from the single exhaust chamber 5 by a horizontal gravity swing plate 11 (b); the upper ends of the third flue gas heat exchange channel 17c and the fourth flue gas heat exchange channel 17d are separated from the single exhaust chamber 5 by a horizontal gravity swing plate 10 (a); at the same time, the lower ends of the lifting baffle 19 (a) and the lifting baffle 18 (b) divide the original "low air resistance state" wind pressure chamber 7 into a first compartment 7a, a second compartment 7b, and a third compartment 7a from left to right. Chamber 7c; the high-temperature flue gas inlet pipe 9 connects to the lower end of the first flue gas heat exchange channel 17a via the third compartment 7c. The upper left side of the first flue gas heat exchange channel 17a connects to the upper right side of the second flue gas heat exchange channel 17b via the upper venting section 18.2 of the lifting partition (b). The lower end of the second flue gas heat exchange channel 17b connects to the lower end of the third flue gas heat exchange channel 17c via the second compartment 7b. The upper left side of the third flue gas heat exchange channel 17c connects to the fourth flue gas heat exchange channel 17 via the upper venting section 19.2 of the lifting partition (a). On the upper right side of d, the lower end of the fourth flue gas heat exchange channel 17d is connected to the lower end of the fifth flue gas heat exchange channel 17e through the first compartment 7a; the upper end of the fifth flue gas heat exchange channel 17e is connected to the single exhaust chamber 5; at this time, the horizontal gravity swing plate 10 and gravity swing plate 11 not only serve to separate the top space, but their lower surfaces also form an almost sealed planar contact with the horizontal support platform 6 at the upper end of the fixed partition 20 and the upper edge of each channel, preventing the flue gas from short-circuiting upwards at the top without passing through the ventilated section.

[0038] Flue gas path and principle under "high flue gas travel state":

[0039] High-flow-rate flue gas from the high-temperature flue gas inlet pipe 9 continuously flows sequentially through the connected third compartment 7c, first flue gas heat exchange channel 17a, upper venting section 18.2 of the lifting baffle plate, second flue gas heat exchange channel 17b, second compartment 7b, third flue gas heat exchange channel 17c, upper venting section 19.2 of the lifting baffle plate, fourth flue gas heat exchange channel 17d, first compartment 7a, fifth flue gas heat exchange channel 17e, single exhaust chamber 5, and exhaust port 3. In this state, the effective heat exchange path of any flue gas is five times that under the "low air resistance state," thus effectively improving the heat utilization rate of the flue gas under low flow conditions. In this serpentine series flow channel with a five-fold travel distance, the flue gas sequentially sweeps across five sets of heat exchange tube bundles, significantly increasing the total heat exchange time and heat exchange area utilization rate. Under low-load conditions, due to the low flue gas velocity and the inherently short residence time of the flue gas in the furnace, if the travel distance of the flue gas within the economizer is not increased, a large amount of waste heat will be lost with the exhaust gas.

[0040] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An economizer flue system, characterized in that: The system includes an economizer shell (1), with a high-temperature flue gas inlet pipe (9) integrally connected to one side of the lower end of the economizer shell (1), and a flue gas outlet (3) provided at the top of the economizer shell (1); the economizer shell (1) includes a heat exchange chamber (17) and a heat exchange tube (2) capable of transmitting liquid water; the heat exchange tube (2) is composed of multiple straight pipe sections and elbows (2.1) for connecting the straight pipe sections end to end; all straight pipe sections of the heat exchange tube (2) are transversely parallel to the heat exchange chamber (17), and there is a flue gas gap between any two adjacent straight sections of the heat exchange tube (2); the beginning and end of the heat exchange tube (2) are the water inlet (71) and the water outlet (72), respectively. Inside the economizer housing (1), from left to right, there are vertical a fixed partition (21), a lifting partition (19), b fixed partition (20) and b lifting partition (18).

2. The economizer flue system according to claim 1, characterized in that: Each elbow (2.1) is located on the outside of the economizer shell (1).

3. The economizer flue system according to claim 1, characterized in that: The economizer shell (1) includes a bottom wall (16) and a top wall. The top wall includes a central flat top wall (4) and a left symmetrical inclined top wall (23.1) and a right symmetrical inclined top wall (23.2). A rectangular exhaust port (3) is hollowed out on the central flat top wall (4).

4. The economizer flue system according to claim 1, characterized in that: A first flue gas heat exchange channel (17a) is formed between the right shell wall (1.2) of the economizer shell (1) and the b lifting partition (18); a second flue gas heat exchange channel (17b) is formed between the b lifting partition (18) and the b fixed partition (20); a third flue gas heat exchange channel (17c) is formed between the b fixed partition (20) and the a lifting partition (19); a fourth flue gas heat exchange channel (17d) is formed between the a lifting partition (19) and the a fixed partition (21); and a fifth flue gas heat exchange channel (17e) is formed between the a fixed partition (21) and the left shell wall (1.1) of the economizer shell (1).

5. The economizer flue system according to claim 4, characterized in that: The first flue gas heat exchange channel (17a), the second flue gas heat exchange channel (17b), the third flue gas heat exchange channel (17c), the fourth flue gas heat exchange channel (17d), and the fifth flue gas heat exchange channel (17e) are all transversely traversed by straight sections of parallel and uniformly distributed heat exchange tubes (2).

6. An economizer flue system according to claim 5, characterized in that: The upper end of the fixed partition (21) is hinged to the gravity pendulum (10) via hinge (12), and the inner side of the upper end of the right shell wall (1.2) is hinged to the gravity pendulum (11) via hinge (13); the gravity pendulum (10) and gravity pendulum (11) are symmetrical about the center line of the fixed partition (20); the upper end of the fixed partition (20) is integrally connected to a horizontal support platform (6); the lifting partition ( 19) The section near the top is the upper ventilation section of the lifting partition a (19.2); the section near the top of the lifting partition b (18) is the upper ventilation section of the lifting partition b (18.2); the upper ventilation sections of the lifting partition a (19.2) and the upper ventilation sections of the lifting partition b (18.2) are evenly perforated with ventilation holes, so that the upper ventilation sections of the lifting partition a (19.2) and the upper ventilation sections of the lifting partition b (18.2) can smoothly pass through the flue gas; The upper ends of the upper ventilation section (19.2) of the lifting partition a and the upper ventilation section (18.2) of the lifting partition b are respectively rotatably mounted with roller a (14) and roller b (15) via bearings; roller a (14) and roller b (15) are tangentially rolled with the lower surfaces of gravity pendulum a (10) and gravity pendulum b (11) respectively.

7. An economizer flue system according to claim 6, characterized in that: This includes two states: low air resistance and high flue gas travel. Under "low air resistance": the lower ends of a fixed partition (21), a lifting partition (19), b fixed partition (20), and b lifting partition (18) are all spaced from the bottom wall (16) of the shell, thereby forming a section of air pressure chamber (7) on the upper side of the bottom wall (16), and one side of the air pressure chamber (7) is connected to the high-temperature flue gas inlet pipe (9); a gravity swing plate (10) is tilted under the support of a roller (14), and the upper end of a gravity swing plate (10) is limited to contact the lower surface of the central flat top wall (4) at the center position. The upper contour of the gravity pendulum (10) divides the smoke vent (3) on the central flat top wall (4) into two halves; at the same time, the gravity pendulum (11) is tilted under the support of the roller (15), and the upper end of the gravity pendulum (11) is in contact with the right edge of the lower surface of the central flat top wall (4), while the upper contour of the gravity pendulum (10) divides the smoke vent (3) on the central flat top wall (4) into two halves; at this time, the symmetrical gravity pendulum (10) and gravity pendulum (11) form a shape that is narrower at the top and wider at the bottom. The main exhaust chamber (5b) is in the shape of an isosceles trapezoid; a) the upper ventilation section (19.2) of the lifting baffle and b) the upper ventilation section (18.2) of the lifting baffle are both vertical in the main exhaust chamber (5b); the upper end of the main exhaust chamber (5b) is connected to the outside through the right half of the exhaust port (3); the upper ends of the first flue gas heat exchange channel (17a), the second flue gas heat exchange channel (17b), the third flue gas heat exchange channel (17c) and the fourth flue gas heat exchange channel (17d) are connected to the lower end of the main exhaust chamber (5b); the a gravity swing plate (10 A secondary flue gas chamber (5a) is formed between the upper part of the secondary flue gas chamber (5a) and the left sloping top wall (23.1). The upper part of the secondary flue gas chamber (5a) is connected to the outside through the left half of the flue gas outlet (3). The upper part of the fifth flue gas heat exchange channel (17e) is connected to the lower part of the secondary flue gas chamber (5a). The lower parts of the first flue gas heat exchange channel (17a), the second flue gas heat exchange channel (17b), the third flue gas heat exchange channel (17c), the fourth flue gas heat exchange channel (17d), and the fifth flue gas heat exchange channel (17e) are all connected to the wind pressure chamber (7). Based on the "low air resistance state", when the a lifting baffle (19) and b lifting baffle (18) descend to the lower end and both descend to the limit contact with the bottom wall of the shell (16), it will change to the "high flue gas stroke state"; Under the "high flue gas travel state": The lower ends of lifting partitions a (19) and b (18) both descend to the limit contact bottom wall (16). The originally tilted gravity pendulums a (10) and b (11), having lost the support of rollers a (14) and b (15), swing downwards to a horizontal position under gravity. The ends of the horizontally positioned gravity pendulums a (10) and b (11) are respectively supported by the left and right ends of the horizontal support platform (6). In this state, the original... Under low air resistance conditions, the main exhaust chamber (5b) and the auxiliary exhaust chamber (5a) are merged into a single exhaust chamber (5); at the same time, the upper ends of the first flue gas heat exchange channel (17a) and the second flue gas heat exchange channel (17b) are separated from the single exhaust chamber (5) by a horizontal gravity swing plate (11); the upper ends of the third flue gas heat exchange channel (17c) and the fourth flue gas heat exchange channel (17d) are separated from the single exhaust chamber (5) by a horizontal gravity swing plate (10). The lower ends of lifting baffles (19) and (18) divide the original "low air resistance state" air pressure chamber (7) into a first compartment (7a), a second compartment (7b), and a third compartment (7c) from left to right; the high-temperature flue gas inlet pipe (9) connects to the lower end of the first flue gas heat exchange channel (17a) through the third compartment (7c), and the upper left side of the first flue gas heat exchange channel (17a) connects to the upper right side of the second flue gas heat exchange channel (17b) through the upper venting section (18.2) of lifting baffle (18). The lower end of the second flue gas heat exchange channel (17b) is connected to the lower end of the third flue gas heat exchange channel (17c) through the second compartment (7b). The upper left side of the third flue gas heat exchange channel (17c) is connected to the upper right side of the fourth flue gas heat exchange channel (17d) through the upper ventilation section (19.2) of the lifting partition a. The lower end of the fourth flue gas heat exchange channel (17d) is connected to the lower end of the fifth flue gas heat exchange channel (17e) through the first compartment (7a). The upper end of the fifth flue gas heat exchange channel (17e) is connected to the single exhaust chamber (5).

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