CN110529872A - Station boiler afterheat utilizing system based on entrance flue gas temperature communication control - Google Patents

Abstract

The present invention provides a waste heat utilization system for power station boilers with intelligent control and utilization of waste heat. The system includes an air preheater and a heat storage device. Data connection with the heat storage valve, the third temperature sensor is set at the flue gas inlet of the air preheater, and the central controller automatically controls the air preheater valve and the heat storage according to the temperature detected by the third temperature sensor The valve opening of the valve. Through the above-mentioned operation, the present invention can store excess heat through the heat storage device after meeting the demand for preheated air when the temperature of the flue gas is high, and can use more heat when the temperature of the flue gas is low. The flue gas enters the air preheater to preheat the air, ensuring the demand for preheated air and saving energy at the same time.

Description

Power Plant Boiler Waste Heat Utilization System Based on Inlet Flue Gas Temperature Communication Control

technical field

The present invention is a part of the subject project jointly developed with the enterprise, and is an improvement on the previous application. It relates to the field of waste heat recovery of heat pipes, and in particular relates to a control method and device for recovering waste heat of flue gas by using heat pipes.

Background technique

With the rapid development of my country's economy, energy consumption is increasing day by day, and the problem of deteriorating urban air quality is becoming more and more prominent. It is urgent to save energy and reduce the emission of harmful environmental substances. In the common steam generation process, one of the main reasons for high energy consumption and serious pollution is that the exhaust temperature of boiler flue gas is too high, which wastes a lot of energy. Therefore, the waste heat of boiler exhaust gas is recovered and reused to achieve energy saving and emission reduction. purpose, while protecting the environment. However, in the prior art, low-temperature corrosion may occur while satisfying the residual heat of the flue gas, so how to avoid low-temperature corrosion is an important issue. At the same time, if only to avoid low-temperature corrosion, the waste heat in the flue gas is wasted Too much, leading to the problem of poor utilization of waste heat, so the above-mentioned related problems need to be solved urgently.

Heat pipe technology is a heat transfer element called "heat pipe" invented by George Grover of Los Alamos National Laboratory in the United States in 1963. It makes full use of the principle of heat conduction and phase change medium. The rapid heat transfer properties of the heat pipe quickly transfer the heat of the heating object to the heat source, and its thermal conductivity exceeds that of any known metal. Compared with the most commonly used shell-and-tube heat exchanger in coal-fired flue gas waste heat recovery, the heat pipe heat exchanger has the advantages of high heat transfer efficiency, compact structure, small pressure loss, and is beneficial to control dew point corrosion. There is more potential in waste heat recovery and utilization.

The heat exchange fluid in the heat pipe is a mixture of steam and water. During the evaporation process of the heat pipe, it will inevitably carry liquid to the steam end. At the same time, because of the exothermic condensation of the condensation end, there will be liquid in the condensation end, and the liquid will inevitably mix with the steam, so that the fluid in the heat pipe is vapor. Liquid mixture, the existence of vapor-liquid mixture causes the gas to mix together, and the heat transfer capacity between the gas and the liquid is reduced, which greatly affects the heat transfer efficiency.

In the boiler waste heat utilization system of the prior art, there is a lack of research on intelligent control, especially the intelligent control when there are multiple waste heat utilization devices at the same time, such as setting heat distribution and so on.

In view of the above problems, the present invention improves on the previous invention, and provides a boiler waste heat utilization device with a new intelligent control structure, which makes full use of heat sources, reduces energy consumption, and realizes intelligent control.

Contents of the invention

Aiming at the above problems, the present invention improves on the previous invention, and provides a new structural boiler waste heat utilization equipment to realize the full utilization of waste heat and its intelligent control.

In order to achieve the above object, the technical scheme of the present invention is as follows:

A utility boiler waste heat utilization system, the system includes an air preheater and a heat storage device, the air preheater is arranged on the main pipe of the flue, the heat storage is arranged on the auxiliary pipe, and the main pipe It forms a parallel pipeline with the auxiliary pipeline. The flue gas in the flue enters the air preheater and heat storage of the main pipeline and the auxiliary pipeline respectively. Steam is generated in the air preheater and stored in the heat storage. The flue gas after heat exchange in the preheater and heat storage unit flows into the flue again;

The air preheater valve is set at the inlet of the air preheater in the main flue to control the flow of flue gas entering the air preheater, and the heat storage valve is set at the inlet pipe of the heat storage of the auxiliary pipeline position, used to control the flow of flue gas entering the heat storage, the system also includes a central controller, the central controller is connected with the data of the air preheater valve and the heat storage valve, and the third temperature sensor is set at The position of the flue gas inlet of the air preheater is used to measure the temperature of the flue gas entering the air preheater; the third temperature sensor is connected to the central controller for data, and the central controller determines the temperature according to the temperature detected by the third temperature sensor. Automatically control the valve opening of the air preheater valve and the heat storage valve.

Preferably, when the temperature measured by the third temperature sensor is lower than a certain temperature, the central controller controls the valve of the air preheater to increase the opening degree, and at the same time controls the valve of the heat storage device to reduce the opening degree to increase the preheating of the incoming air When the temperature measured by the third temperature sensor is higher than a certain temperature, the central controller controls the valve of the air preheater to reduce the opening degree, and at the same time controls the valve of the heat storage device to increase the opening degree to reduce the inflow Flue gas flow of the air preheater.

Preferably, if the temperature detected by the first temperature sensor is lower than the temperature detected by the second temperature sensor, the central controller controls the fan to stop running. If the temperature detected by the first temperature sensor is higher than the temperature detected by the second temperature sensor, the central controller controls the fan to start running.

Preferably, when the central controller detects that there is smoke passing through the pipeline, the central controller automatically controls the fan to stop running; when the central controller detects that there is no smoke passing through the pipeline, the central controller controls the upstream valve and the downstream valve to close, and the air pre- The pipeline where the heater and the heat storage are located forms a circulation pipeline, and the central controller automatically controls the fan to start running.

Preferably, the air preheater includes a heat pipe, a flue gas channel and an air channel, the heat pipe includes an evaporation end and a condensation end, the condensation end is arranged in the air passage, and the evaporation end is arranged in the flue; the evaporation end absorption boiler The waste heat of the flue gas in the flue is transferred to the air in the air channel through the condensing end, and the preheated air enters the boiler furnace for combustion.

Preferably, a stabilizing device is provided in the heat collecting tube, and the stabilizing device is a sheet structure, and the sheet structure is arranged on the cross section of the heat collecting tube; the stabilizing device is composed of a square through hole and a regular octagonal through hole , the side length of the square through hole is equal to the side length of the regular octagonal through hole, the four sides of the square through hole are respectively the sides of four different regular octagonal through holes, and the four sides of the regular octagonal through hole The sides spaced apart from each other are the sides of four different square through holes.

Preferably, the cross section of the heat collecting tube is square.

Preferably, the distance between adjacent stabilizing devices is K1, the side length of the square is B1, the heat pipe is a square section, the side length of the heat pipe is B2, the acute angle formed between the heat pipe and the horizontal plane is A, and the distance between the centers of adjacent heat pipes is The spacing is K2 to meet the following requirements:

c*K2/B2＝d*(K1/B2) ² +ef*(K1/B2) ³ -h*(K1/B2);

Where d, e, f, h are parameters,

1.239<d<1.240, 1.544<e<1.545, 0.37<f<0.38, 0.991<h<0.992; c=1/cos(A) ⁿ , where 0.090<n<0.098, preferably n=0.093.

11<B2<46mm;

1.9<B1<3.2mm;

18<K1<27mm.

16<K2<76mm.

Compared with the prior art, the present invention has the following advantages:

1) Through the above-mentioned operation, the present invention can store excess heat through the heat storage device after satisfying the demand for preheated air when the temperature of the flue gas is high, and can store the excess heat when the temperature of the flue gas is low. More flue gas enters the air preheater to preheat the air, ensuring the demand for preheated air and saving energy at the same time.

2) The present invention provides a power plant boiler waste heat utilization system with a new structure of a stabilizing device combining a new square through hole and a regular octagonal through hole. The square hole and the regular octagonal hole are formed through the square and the regular octagon. The included angles formed by the sides are greater than or equal to 90 degrees, so that the fluid can fully flow through each position of each hole, and avoid or reduce the short circuit of the fluid flow. The invention separates the two-phase fluid into a liquid phase and a gas phase through a stabilizing device with a new structure, divides the liquid phase into small liquid masses, and divides the gas phase into small bubbles, inhibits the backflow of the liquid phase, promotes the smooth flow of the gas phase, and stabilizes the flow rate. The role of improving the heat transfer effect. Compared with the stabilizing device in the prior art, the stabilizing effect is further improved, the heat transfer is enhanced, and the manufacture is simple.

3) The present invention makes the square and regular octagonal through-holes evenly distributed through a reasonable layout, so that the fluid on the overall transverse street is evenly divided, and avoids the uneven division of the ring structure along the circumferential direction in the prior art. Even problem.

4) The present invention evenly distributes the spacing between square holes and regular octagonal holes, so that the large holes and small holes are evenly distributed on the overall cross section, and the positions of the large holes and small holes of the adjacent stabilizing devices change, so that Separation works better.

5) In the present invention, the stabilizing device has a sheet structure, so that the stabilizing device has a simple structure and a reduced cost.

6) The present invention studies the above-mentioned parameters by setting the distance between adjacent stabilizing devices in the height direction of the heat-absorbing tube, the side length of the hole of the stabilizing device, the pipe diameter of the heat-absorbing pipe, the tube spacing and other parameters. The best relationship size, so as to further achieve the effect of steady flow, reduce noise and improve heat transfer effect.

7) The present invention conducts extensive research on the heat transfer laws caused by the changes of various parameters of the stabilizing device, and realizes the optimal relational expression of the heat transfer effect under the condition of satisfying the flow resistance.

8) A waste heat utilization device with a new structure is provided. By arranging a flow equalizing pipe between the heat pipes, the uniform pressure in each heat pipe, the uniform distribution of the fluid flow rate and the uniform distribution of the fluid motion resistance are guaranteed.

Description of drawings

Fig. 1 is a schematic structural view of the air preheater of the present invention.

Fig. 2 is a schematic diagram of the intelligent control of the flue gas waste heat utilization device of the present invention.

Fig. 3 cross-sectional structure schematic diagram of stabilizing device of the present invention;

Fig. 4 is a schematic diagram of another cross-sectional structure of the stabilizing device of the present invention;

Fig. 5 is a schematic diagram of the arrangement of the stabilizing device of the present invention in the heat pipe;

Fig. 6 is a cross-sectional schematic diagram of the arrangement of the stabilizing device in the heat pipe of the present invention;

Fig. 7 is a schematic cross-sectional view of a heat pipe provided with a flow equalizing pipe according to the present invention.

Fig. 8 is a schematic structural diagram of a flue gas waste heat utilization device provided with a bypass flue according to the present invention.

In the figure: 1 air preheater, 2 heat storage, 3 central controller, 4 stabilizer, 5 air preheater valve, 6 upstream valve, 7 downstream valve, 8 air outlet, 9 air inlet, 10-heat pipe, 11 shell, 12 main pipe, 13 auxiliary pipe, 14 flue, 15 bypass valve, 16 air passage, 17 heat storage valve, 18 equalizing pipe

Detailed ways

The specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

In this article, if there is no special explanation, when it comes to formulas, "/" means division, and "×" and "*" mean multiplication.

The specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

A utility boiler flue gas waste heat utilization system, the waste heat utilization system includes an air preheater 1, the air preheater 1 includes a heat pipe 10, a flue gas channel 14 and an air channel 16, and the heat pipe 10 includes an evaporation The condensing end 101 and the condensing end 102, the condensing end 102 is arranged in the air passage 12, and the evaporating end 101 is arranged in the flue. The evaporating end 101 absorbs the waste heat of the flue gas in the boiler flue, and transfers the heat to the air in the air channel 12 through the condensing end 102 . The preheated air enters the boiler furnace for combustion support.

During operation, the heat pipe of the present invention absorbs heat from the flue gas through the evaporating end 101, and then releases heat to the air at the condensing end, and the fluid condenses, and then enters the evaporating end 101 by gravity.

During the operation of the waste heat utilization device, there is uneven distribution of fluid, and because different heat pipes absorb different heat during the heat collection process, resulting in different fluid temperatures in different heat pipes, and even fluids in some heat pipes, such as water becoming gas In the liquid two-phase state, the fluid in some heat pipes is still liquid, so that the pressure in the heat pipe increases because the fluid turns into steam, so by setting a flow equalizer between the heat pipes, the fluids can flow into each other in the heat pipe, so that The pressure distribution in all heat pipes is made to be balanced, and the fluid distribution is also promoted to be balanced.

As an option, as shown in FIG. 8 , flow equalizing pipes 18 are arranged between the heat pipes. A flow equalizing pipe 18 is arranged between at least two adjacent heat pipes 10 . In the research, it is found that in the process of heat absorption and heat release of the evaporator tube, the heat absorption and release heat of the heat absorption and heat release tubes in different positions will be different, resulting in different pressures or temperatures between the heat pipes 10, which will cause some heat pipes 10 If the temperature is too high, the service life will be shortened. Once a problem occurs in the heat pipe 10, the whole waste heat utilization system may become unusable. Through a lot of research in the present invention, the flow equalizing pipe 18 is arranged on adjacent heat pipes, which can make the fluid in the heat pipe 10 with high pressure quickly flow to the heat pipe 10 with low pressure when the heat pipes are heated differently and cause different pressures. Thereby maintaining the overall pressure balance and avoiding local overheating or overcooling.

Preferably, from the evaporating end of the heat pipe 10 to the condensing end of the heat pipe 10, a plurality of flow equalizing pipes 18 are arranged between adjacent heat pipes 10 . By arranging a plurality of equalizing pipes, the pressure of the fluid can be continuously balanced during the process of absorbing heat and evaporating, so as to ensure the pressure balance in the entire heat pipe.

Preferably, at the evaporating end 101 , the distance between adjacent flow equalizing tubes 18 decreases continuously from the evaporating end of the heat pipe 10 to the condensing end of the heat pipe 10 . The purpose of this is to set up more flow equalizing tubes, because as the fluid flows upwards, the fluid absorbs heat continuously, and as the fluid continuously absorbs heat, the pressure in different heat pipes becomes more and more uneven, so through the above settings, It can ensure that the pressure balance is achieved as soon as possible during the fluid flow process.

Preferably, at the evaporating end 101 , from the evaporating end of the heat pipe 10 to the condensing end of the heat pipe 10 , the distance between adjacent flow equalizing pipes decreases continuously and becomes larger and larger. It is found through experiments that the above setting can ensure better and faster pressure equalization in the process of fluid flow. This is also the best connection method obtained through a large number of studies on the law of pressure distribution changes.

Preferably, at the evaporating end 101 , the diameter of the equalizing pipe 18 increases continuously from the evaporating end of the heat pipe 10 to the condensing end of the heat pipe 10 . The purpose of this is to ensure a larger communication area, because as the fluid flows upwards, the fluid absorbs heat continuously to generate steam, and as the steam is continuously generated, the temperature and pressure in different heat pipes become more and more uneven, so through the above The setting can ensure that the pressure equalization is achieved as soon as possible during the fluid flow.

Preferably, at the evaporating end 101 , from the evaporating end of the heat pipe 10 to the condensing end of the heat pipe 10 , the diameter of the equalizing pipe 18 increases more and more. It is found through experiments that the above setting can ensure better and faster pressure equalization in the process of fluid flow. This is also the best connection method obtained through a large number of studies on the law of pressure distribution changes.

Preferably, at the condensing end 102 , the distance between adjacent flow equalizing tubes 18 increases continuously from the evaporating end of the heat pipe 10 to the condensing end of the heat pipe 10 . The purpose of this is to set fewer flow sharing tubes and reduce costs. Because as the lower part of the condensing end 102 goes upward, the steam in the heat pipe continuously releases heat and condenses, and as the fluid continuously releases heat, the pressure in the heat pipe becomes smaller and smaller, so the uneven phenomenon becomes more and more relaxed. Therefore, through the above The setting can save materials, and setting the equalizing pipe according to the pressure change can ensure that the pressure equalization is achieved as soon as possible during the fluid flow process.

Preferably, at the condensing end 102 , from the evaporating end of the heat pipe 10 to the condensing end of the heat pipe 10 , the distance between adjacent flow equalizing pipes increases continuously. It is found through experiments that the above setting can ensure better and faster pressure equalization in the process of fluid flow. This is also the best connection method obtained through a large number of studies on the law of pressure distribution changes.

Preferably, at the condensing end 102 , the diameter of the equalizing pipe 18 decreases continuously from the evaporating end of the heat pipe 10 to the condensing end of the heat pipe 10 . The purpose of this is to set a guaranteed reduced connected area and reduce costs. It is the same principle as the previous distance increasing.

Preferably, at the condensing end 102 , from the evaporating end of the heat pipe 10 to the condensing end of the heat pipe 10 , the diameter of the flow equalizing pipe 18 decreases gradually to a larger extent. It is found through experiments that the above setting can ensure better and faster pressure equalization in the process of fluid flow. This is also the best connection method obtained through a large number of studies on the law of pressure distribution changes.

Because of the heat exchange of steam in the heat pipe, the vapor-liquid two-phase flow occurs in the heat pipe. On the one hand, the heat pipe will inevitably carry the liquid into the heat pipe during the evaporation process. At the same time, due to the exothermic condensation at the condensation end, there will be Liquid, the liquid also inevitably enters the steam, so that the fluid in the heat pipe is a vapor-liquid mixture. At the same time, the heat pipe will produce non-condensable gas due to aging during the operation process. The non-condensable gas generally rises to the condensation end of the upper part of the heat pipe. The presence of condensate causes the pressure in the condensing end of the heat pipe to increase, and the pressure causes the liquid to flow into the heat pipe. Greatly affects the efficiency of heat exchange. Therefore, the present invention adopts a new structure to divide the vapor phase and the liquid phase, so that the heat exchange is strengthened.

A stabilizing device 4 is arranged inside the heat pipe, and the structure of the stabilizing device 4 is shown in FIGS. 2 and 3 . The stabilizing device 4 is a sheet structure, and the sheet structure is arranged on the cross section of the heat pipe 10; the stabilizing device 4 is composed of a square and a regular octagonal structure, thereby forming a square through hole 41 and a regular octagonal through hole 42. As shown in Figure 2, the side length of the square through hole 41 is equal to the side length of the regular octagonal through hole 42, and the four sides 43 of the square through hole are respectively the sides 43 of four different regular octagonal through holes, and the regular octagonal deformation The four sides 43 spaced apart from each other are the sides 43 of four different square through holes.

The present invention adopts the stabilizing device of novel structure, has the following advantages:

1) The present invention provides a new type of stabilizing device with a combination of a new square through hole and a regular octagonal through hole, through the square and the regular octagon, the angle formed by the sides of the formed square hole and the regular octagonal hole All are greater than or equal to 90 degrees, so that the fluid can fully flow through each position of each hole, and avoid or reduce the short circuit of the fluid flow. The invention separates the two-phase fluid into a liquid phase and a gas phase through a stabilizing device with a new structure, divides the liquid phase into small liquid masses, and divides the gas phase into small bubbles, inhibits the backflow of the liquid phase, promotes the smooth flow of the gas phase, and stabilizes the flow rate. It has the effect of reducing vibration and noise, and improves the heat transfer effect. Compared with the stabilizing device in the prior art, the stabilizing effect is further improved, the heat transfer is enhanced, and the manufacture is simple.

2) The present invention makes the square and regular octagonal through-holes evenly distributed through a reasonable layout, so that the fluid on the overall cross-street surface is evenly divided, avoiding the uneven division of the ring structure along the circumferential direction in the prior art. Even problem.

3) The present invention evenly distributes the spacing between the square hole and the regular octagonal through hole, so that the large hole and the small hole are evenly distributed on the overall cross section, and the positions of the large hole and the small hole of the adjacent stabilizing device change, Make the separation effect better.

4) In the present invention, the stabilizing device has a sheet structure, so that the stabilizing device has a simple structure and a reduced cost.

In the present invention, by setting the annular stabilizing device, it is equivalent to increasing the inner heat exchange area in the heat pipe, strengthening the heat exchange and improving the heat exchange effect.

The present invention divides the gas-liquid two-phase at all cross-sectional positions of all heat exchange tubes, thereby realizing the separation of the gas-liquid interface and the gas-phase boundary layer and the contact area of the cooling wall surface on the entire heat exchange tube section, and enhancing the disturbance. The noise and vibration are greatly reduced, and the heat transfer is enhanced.

Preferably, the stabilizing device includes two types, as shown in FIGS. 3 and 4 , the first type is a square central stabilizing device, and the square is located at the center of the heat pipe or condenser pipe, as shown in FIG. 4 . The second type is a regular octagon center stabilizing device, and the regular octagon is located at the center of the heat pipe or condenser pipe, as shown in FIG. 3 . As a preference, the above two types of stabilizing devices are arranged adjacently, that is, the types of stabilizing devices arranged adjacently are different. That is, adjacent to the square central stabilizing device is a regular octagonal central stabilizing device, and adjacent to the regular octagonal central stabilizing device is a square central stabilizing device. The present invention evenly distributes the intervals between square holes and regular octagonal holes, so that large holes and small holes are evenly distributed on the overall cross-section, and through the position changes of large holes and small holes of adjacent stabilizing devices, large holes can pass through The fluid in the hole passes through the small hole next, and the fluid passing through the small hole passes through the large hole next, further separating and promoting the mixing of gas and liquid, making the separation and heat exchange effect better.

Preferably, the cross section of the heat pipe 10 is square.

Preferably, a plurality of stabilizing devices are arranged in the evaporating end, and at the evaporating end 101 , the distance between the stabilizing devices becomes smaller from the evaporating end of the heat pipe 10 to the condensing end of the heat pipe 10 . Let the distance from the evaporation end of the heat pipe be H, and the distance between adjacent stabilizing devices be S, S=F ₁ (H), that is, S is a function of the variable with height H, and S' is a function of S Derivatives meet the following requirements:

S'<0;

The main reason is that the liquid in the heat pipe is continuously heated to generate steam. During the rising process, the steam is constantly increasing, resulting in more and more gas in the gas-liquid two-phase flow, because the vapor phase in the vapor-liquid two-phase flow More and more, the heat exchange capacity in the heat pipe will be relatively weakened with the increase of the vapor phase, and the vibration and noise will also increase continuously with the increase of the vapor phase. Therefore, the distance between adjacent stabilizing devices that need to be provided becomes shorter and shorter.

Through experiments, it is found that through the above-mentioned setting, the vibration and noise can be reduced to the greatest extent, and the heat exchange effect can be improved at the same time.

Further preferably, at the evaporating end 101 , from the evaporating end of the heat pipe 10 to the condensing end of the heat pipe 10 , the distance between adjacent stabilizing devices becomes shorter and shorter. That is, S" is the second derivative of S, which meets the following requirements:

S">0;

Through experiments, it is found that by setting in this way, the vibration and noise can be further reduced by about 7%, and the heat exchange effect can be improved by about 8%.

Preferably, a plurality of stabilizing devices are arranged in the evaporation end 101 , and at the evaporation end 101 , from the evaporation end of the heat pipe 10 to the condensation end of the heat pipe 10 , the side length of the square becomes smaller and smaller. The distance from the lower end of the heat pipe is H, the side length of the square is C, C=F ₂ (H), and C' is the first derivative of C, which meets the following requirements:

C'<0;

Further preferably, at the evaporating end 101 , from the evaporating end of the heat pipe 10 to the condensing end of the heat pipe 10 , the side lengths of the squares are continuously increasing with smaller and smaller amplitudes. C" is the second derivative of C, which meets the following requirements:

C”>0.

For specific reasons, see the change in spacing between stabilizers above.

Preferably, the distance between adjacent stabilizing means remains constant.

As preferably, a plurality of stabilizing devices are arranged in the condensing end, and at the condensing end 102, from the inlet of the condensing end 102 (that is, starting from the position where the heat pipe 10 extends into the air channel) to the end of the condensing end, the spacing between the stabilizing devices is constantly increasing . Suppose the distance from the position where the heat pipe 10 stretches into the air channel is H, the distance between adjacent stabilizing devices is S, S=F ₁ (H), that is, S is a function of the variable with the height H, and S' is S The first derivative of , satisfying the following requirements:

S'>0;

The main reason is that the steam in the condensing end is continuously condensing during the rising process, and the steam is getting less and less, resulting in less and less gas in the gas-liquid two-phase flow, because the vapor phase in the vapor-liquid two-phase flow is getting smaller and smaller. less. Therefore, the distance between the adjacent stabilizing devices needs to be set longer and longer, so that the cost can be further saved, the same effect can be achieved, and the flow resistance can be reduced.

Through experiments, it is found that through the above-mentioned setting, the vibration and noise can be reduced to the greatest extent, and the heat exchange effect can be improved at the same time.

Further preferably, at the condensing end 102, from the inlet of the condensing end 102 (that is, from the position where the heat pipe 10 extends into the air channel) to the end of the condensing end, the distance between adjacent stabilizing devices increases continuously. That is, S" is the second derivative of S, which meets the following requirements:

S">0;

Through experiments, it is found that by setting in this way, the resistance of about 7% can be further reduced, and at the same time, basically the same heat exchange effect can be achieved.

As preferably, a plurality of stabilizing devices are arranged in the condensing end 102, and at the condensing end 102, from the inlet of the condensing end 102 (that is, starting from the position where the heat pipe 10 stretches into the air channel) to the end of the condensing end, the side length of the square becomes more and more big. Suppose the distance from the position where the heat pipe 10 extends into the water tank is H, the side length of the square is C, C=F ₂ (H), and C' is the first derivative of C, which meets the following requirements:

C'>0;

Further preferably, at the condensing end 102, from the lower end of the heat pipe upwards, the side length of the square increases continuously. C" is the second derivative of C, which meets the following requirements:

C”>0.

For specific reasons, see the change in spacing between stabilizers above.

Preferably, the distance between adjacent stabilizing means remains constant.

Through analysis and experiments, we know that the distance between the stabilizing devices should not be too large. If it is too large, the effect of shock absorption and noise reduction and separation will not be good. At the same time, it should not be too small. If it is too small, the resistance will be too large. Similarly, the square The length of the side can not be too large or too small, it will also lead to poor effect of shock absorption and noise reduction or excessive resistance, so the present invention, through a large number of experiments, first satisfies the normal flow resistance (total pressure is below 2.5Mpa) , or when the resistance along the path of a single heat pipe is less than or equal to 5Pa/M), the vibration and noise reduction can be optimized, and the best relationship of each parameter has been sorted out.

Preferably, the present invention is arranged on a vertical flue. The heat pipe forms a certain angle with the extending direction of the flue. That is, the heat pipe is at a certain angle to the horizontal.

Preferably, the distance between adjacent stabilizing devices is K1, the side length of the square through hole is B1, the heat pipe has a square section, the side length of the square section of the heat pipe is B2, and the acute angle formed between the heat pipe and the horizontal plane is A, which meets the following requirements :

c*K1/B2=a*Ln(B1/B2)+b

Where a, b are parameters, where 1.725<a<1.733, 4.99<b<5.01; c=1/cos(A) ^m , where 0.085<m<0.095, preferably m=0.090.

11<B2<46mm;

1.9<B1<3.2mm;

18<K1<27mm.

0°<A<50°.

Preferably, 0°<A<25°.

Further preferably, as B1/B2 increases, a becomes smaller and b becomes larger.

As preferred, a=1.728, b=4.997;

Preferably, the side length B1 of the square through hole is the average value of the inner side length and the outer side length of the square through hole, and the side length B2 of the square section of the heat pipe is the average value of the inner side length and the outer side length of the heat pipe.

Preferably, the length of the outer side of the square through hole is equal to the length of the inner side of the square section of the heat pipe.

As A increases, m becomes smaller and smaller.

Preferably, as B2 increases, B1 also increases continuously. But with the increase of B2, the increasing range of B1 becomes smaller and smaller. This change in law is obtained through a large number of numerical simulations and experiments. Through the change in the above law, the heat exchange effect can be further improved and the noise can be reduced.

Preferably, as B2 increases, K1 decreases continuously. But with the increase of B2, the decreasing range of K1 becomes smaller and smaller. This change in law is obtained through a large number of numerical simulations and experiments. Through the change in the above law, the heat exchange effect can be further improved and the noise can be reduced.

Through analysis and experiments, it is known that the distance between heat pipes should also meet certain requirements, such as not being too large or too small. The stabilizing device also has certain requirements on the distance between the heat pipes. Therefore, through a large number of experiments, the present invention optimizes the vibration and noise reduction under the condition that the normal flow resistance (the total pressure is below 2.5Mpa, or the resistance along the course of a single heat pipe is less than or equal to 5Pa/M) is satisfied first. , sorting out the best relationship of each parameter.

The distance between adjacent stabilizing devices is K1, the side length of a square is B1, the heat pipe is a square section, the side length of the heat pipe is B2, the acute angle formed between the heat pipe and the horizontal plane is A, and the distance between the centers of adjacent heat pipes is K2 Meet the following requirements:

c*K2/B2＝d*(K1/B2) ² +ef*(K1/B2) ³ -h*(K1/B2);

Where d, e, f, h are parameters,

1.239<d<1.240, 1.544<e<1.545, 0.37<f<0.38, 0.991<h<0.992; c=1/cos(A) ⁿ , where 0.090<n<0.098, preferably n=0.093.

11<B2<46mm;

1.9<B1<3.2mm;

18<K1<27mm.

16<K2<76mm.

The distance K2 between the centers of adjacent heat pipes refers to the distance between the centerlines of the heat pipes.

As A increases, n becomes smaller and smaller.

0°<A<50°.

Preferably, 0°<A<25°.

More preferably, d=1.2393, e=1.5445, f=0.3722, h=0.9912;

Preferably, as K1/B2 increases, d, e, f become larger and h becomes smaller.

Preferably, as B2 increases, K2 increases continuously, but with the increase of B2, the range of K2 continuously increases becomes smaller and smaller. This change in law is obtained through a large number of numerical simulations and experiments, and the heat exchange effect can be further improved through the change in the above law.

Preferably, the length of the evaporation end (the length of the heat pipe located in the flue 1 ) is between 1000-1800 mm. More preferably, between 1200-1400mm.

Preferably, the length of the condensation end is between 500-900mm. More preferably, between 600-700mm.

By optimizing the optimal geometric scale of the above formula, the best effect of shock and noise reduction can be achieved under normal flow resistance conditions.

For other parameters, such as pipe wall, wall thickness and other parameters can be set according to normal standards.

There are multiple heat pipes, and the distribution density of the heat pipes becomes smaller and smaller along the flow direction of the flue gas. In the numerical simulation and experiment, it is found that along the flow direction of the flue gas, the heat received by the heat pipe is getting smaller and smaller, and the temperature of the heat pipe at different positions is also different, resulting in uneven local heating. Because with the continuous heat exchange of the flue gas, the temperature of the flue gas is also continuously decreasing, resulting in a decrease in the heat exchange capacity. Therefore, the present invention sets the density of the heat pipes at different positions of the flue gas passage, so that the Along the flue gas flow direction, the heat absorption capacity of the heat pipe keeps decreasing, so that the overall heat pipe temperature remains basically the same, thereby improving the overall heat exchange efficiency, saving materials, avoiding local damage caused by uneven temperature, and prolonging the service life of the heat pipe.

Preferably, along the flow direction of the flue gas, the distribution density of the heat pipes increases continuously with a smaller and smaller range. As for the variation of the distribution density of the heat pipes, the present invention has carried out a large number of numerical simulations and experiments, so as to obtain the above-mentioned variation law of the distribution density of the heat pipes. Through the above-mentioned changing rules, materials can be saved, and at the same time, the heat exchange efficiency can be increased by about 9%.

Preferably, the diameter and length of each heat pipe 10 are the same.

As preferably, along the flue gas flow direction, the length of the flue that distributes the heat pipe is C, and along the flue gas flow direction, the density of the heat pipe 10 at the rear end of the flue is M _tail , and the distance from the heat pipe 10 tail is 1 position The law of heat pipe density M is as follows: M=b*M _tail +c*M _tail *(l/C) ^a , wherein a, b, c are coefficients, satisfying the following requirements:

1.083<a<1.127, 0.982<b+c<1.019, 0.483<b<0.648.

Preferably, as l/C increases, a decreases gradually.

As preferred, 1.09<a<1.11, b+c=1, 0.543<b<0.578;

The above optimized formula is obtained through a large number of experiments and numerical simulations, which can make the distribution density of the heat pipes of the heat pipes reach an optimal distribution, uniform heat distribution on the whole, good heat exchange effect, and save materials at the same time. Preferably, the vertical portion 101 is arranged in the air channel. By heating the air channels, the heated air is used directly for combustion.

Preferably, there are multiple heat pipes, and along the flow direction of the flue gas, the diameters of the heat pipes become smaller and smaller. In the numerical simulation and experiment, it is found that along the flow direction of the flue gas, the heat received by the heat pipe is getting smaller and smaller, and the temperature of the heat pipe at different positions is also different, resulting in uneven local heating. Because with the continuous heat exchange of the flue gas, the temperature of the flue gas is also continuously decreasing, resulting in a decrease in the heat exchange capacity. Therefore, the present invention sets different diameters of the heat pipes at different positions of the flue gas passage, so that Along the flue gas flow direction, the heat absorption capacity of the heat pipe keeps decreasing, so that the overall heat pipe temperature remains basically the same, thereby improving the overall heat exchange efficiency, saving materials, avoiding local damage caused by uneven temperature, and extending the service life of the heat pipe .

Preferably, along the flow direction of the flue gas, the pipe diameter of the heat pipe is gradually increased with decreasing diameter. As the change of the diameter of the heat pipe, the present invention has carried out a large number of numerical simulations and experiments, so as to obtain the above-mentioned change law of the diameter of the heat pipe. Through the above-mentioned changing rules, materials can be saved, and at the same time, the heat exchange efficiency can be increased by about 8%.

Preferably, the distribution density and length of all heat pipes 10 are the same.

Along the flue gas flow direction, the length of the flue of the distributed heat pipe is C. Along the flue gas flow direction, the last end of the flue, that is, the diameter of the heat pipe at the end of the heat pipe is D _tail , and the distance from the end of the heat pipe is l. The heat pipe diameter D rule is as follows:

D ² ＝b*(D _tail ) ² +c*(D _tail ) ² *(l/C) ^a , where a, b, and c are coefficients, meeting the following requirements:

1.085<a<1.125, 0.985<b+c<1.015, 0.485<b<0.645.

Preferably, as l/C increases, a decreases gradually.

As preferred, 1.093<a<1.106, b+c=1, 0.548<b<0.573;

The above optimized formula is obtained through a large number of experiments and numerical simulations, which can make the distribution density of the heat pipes reach an optimal distribution, uniform heat distribution on the whole, good heat exchange effect, and save materials at the same time.

Preferably, along the flue gas flow direction, the length from the condensation end to the air channel becomes smaller and smaller.

Preferably, along the flow direction of the flue gas, the length from the condensing end to the air passage increases continuously with decreasing amplitude. The changes in the above rules are similar to the changes in the distribution density and diameter above. They are all along the flow direction of the flue gas, reducing the heat transfer area, so that along the flow direction of the flue gas, the heat absorption capacity of the condensing pipe is continuously reduced, so as to be suitable for heat transfer. The number gradually decreased.

Further preferably, as shown in FIG. 1 , the waste heat utilization system includes a heat storage 2 , and the flue gas channel includes a main pipe 12 and a secondary pipe 13 . The heat pipe is arranged on the main pipe 12 of the flue. The heat accumulator 2 is arranged on the secondary pipeline 13, and the main pipeline 12 and the secondary pipeline 12 form a parallel pipeline. The flue gas in the flue 14 enters the air preheater 1 and the heat storage 2 of the main pipeline 12 and the auxiliary pipeline 13 respectively, heats the air through the heat pipe, and stores heat in the heat storage 2. The flue gas after heat exchange in the heat accumulator 2 flows into the main flue again.

In the above system, while the air is heated by the waste heat of the flue gas, the heat storage device can be used for heat storage.

As shown in Figure 1, the system includes a heat accumulator valve 17 and an air preheater valve 5, an upstream valve 6 and a downstream valve 7, and the upstream valve 6 is arranged in the flue upstream of the air preheater 1 and the heat accumulator 2 14, used to control the total flue gas flow into the air preheater 1 and heat storage 2, the downstream valve 7 is set on the flue 14 downstream of the air preheater 1 and heat storage 2, the air preheater The valve 5 is set at the entrance of the air preheater 1 of the main flue 12, and is used to control the flow of flue gas entering the air preheater 1, and the heat storage valve 17 is set at the side of the heat storage 2 of the auxiliary pipeline 13. The location of the inlet pipe to control the flow of flue gas entering the heat storage 2, the system also includes a central controller that communicates with the heat storage valve 17, the air preheater valve 5 and the upstream valve 6 , The downstream valve 7 is connected for communication data. The central controller controls the opening and closing of the heat accumulator valve 17, the air preheater valve 5, the upstream valve 6, and the downstream valve 7, as well as the opening degree, thereby controlling the smoke entering the air preheater 1 and the heat accumulator 2. capacity.

As a preference, as shown in Figure 8, the system is also provided with a bypass pipe connected to the flue 14, the connection position between the bypass pipe and the flue 14 is located upstream of the upstream valve 6, and the bypass pipe is provided with Bypass valve 15. The bypass valve 15 is in data connection with the central controller 3 . The opening and closing of the bypass valve 15 can ensure whether the flue gas passes through the air preheater 1 and the heat storage device 2 .

Preferably, the bypass valve 15 is opened, and the upstream valve 6 and the downstream valve 7 are closed.

(1) Control the opening and closing of the valve according to the flue gas flow

Preferably, a smoke sensor is provided in the flue 14 upstream of the upstream valve 6, and the smoke sensor is used to detect whether there is smoke flowing through the flue. The smoke sensor is connected to the central controller for data, and the central controller controls the opening and closing of the upstream valve 6 and the downstream valve according to the data detected by the flue sensor.

When the central controller detects that there is flue gas passing through the flue 14, for example, when the boiler is running, the central controller controls the upstream valve 6 and the downstream valve 7 to be open, and the flue gas can enter the air preheater 1 and heat storage 2. Exhaust the smoke after the heat exchange is completed. When the central controller detects that there is no flue gas passing through the flue 14, for example, when the boiler stops running, the central controller controls the upstream valve 6 and the downstream valve 7 to close, and the pipeline where the air preheater 1 and the heat storage device 2 are located forms a cycle pipeline. At this time, the heat stored in the heat accumulator 2 is used to heat the air preheater 1 to preheat the air. Through the above-mentioned operation, when there is flue gas, under the condition that the amount of preheated air generated by the air preheater 1 is satisfied, excess heat can be stored in the heat storage device 2, and when there is no residual heat of flue gas In some cases, the heat stored in the waste heat of the flue gas is used to heat the air preheater 1 to meet the actual working requirements of the air preheater 1 . In this way, the residual heat of the flue gas can be fully utilized to avoid excessive waste of heat.

Preferably, the bypass valve 15 is opened, and the upstream valve 6 and the downstream valve 7 are closed.

Preferably, when the smoke sensor detects smoke, the central controller controls the bypass valve 15 to close, and the upstream valve 6 and the downstream valve 7 to open.

Preferably, when the smoke sensor detects that there is no smoke, the central controller controls the bypass valve 15 to open, and the upstream valve 6 and the downstream valve 7 to close.

(2) Control the operation of the fan in the closed circulation system according to the flue gas flow

As a preference, a fan is provided on the auxiliary pipeline 13 to close the upstream valve 6 and the lower valve 7 in the absence of waste heat of the flue gas. The operation of the fan makes the air preheater 1 and the heat storage 2 located The lines form a circulation line.

Preferably, the fan is connected to the central controller for data, and the central controller 3 automatically controls the operation of the fan according to the data monitored by the flue sensor.

When the central controller detects that there is smoke passing through the pipeline, the central controller automatically controls the fan to stop running. When the central controller detects that there is no flue gas passing through the pipeline, the central controller automatically controls the fan to start running. By controlling the intelligent operation of the fan, the intelligent control of the operation of the fan can be realized according to the actual situation, which improves the intelligence of the system.

(3) Control the operation of the fan according to the dual temperature detection

Preferably, a first temperature sensor is arranged in the heat storage 2 for detecting the temperature of the heat storage material in the heat storage. The air preheater is provided with a second temperature sensor for detecting the temperature of the air in the air preheater 1 . The first temperature sensor and the second temperature sensor are in data connection with the central controller 3 . The upstream valve 6 and the downstream valve 7 are closed, and the central controller 3 automatically controls the operation of the fan according to the temperature detected by the first temperature sensor and the second temperature sensor.

If the temperature detected by the first temperature sensor is lower than the temperature detected by the second temperature sensor, the central controller 3 controls the fan to stop running. If the temperature detected by the first temperature sensor is higher than the temperature detected by the second temperature sensor, the central controller 3 controls the fan to start running.

By controlling the operation of the fan through the detected temperature, the air preheater can be automatically heated. Because it is found in the process of research and development and experiments that when the heat of the heat storage is gradually used up, the temperature of the gas coming out of the heat storage will be lower than the temperature of the air in the air preheater 1. In this case It is impossible to use the heat storage to heat the air preheater, but it may cause the heat of the air preheater to be taken away. Therefore, by intelligently controlling the operation of the fan according to the detected temperature, the cycle between the heat storage device 2 and the air preheater 1 is intelligently controlled, and the air preheating effect is improved.

(4) Control the opening of the valve according to the flue gas temperature at the inlet of the air preheater

Preferably, the third temperature sensor is arranged at the flue gas inlet of the air preheater 1 for measuring the temperature of the flue gas entering the air preheater. The third temperature sensor is in data connection with the central controller 3, and the central controller automatically controls the valve openings of the air preheater valve 5 and the heat storage valve 17 according to the temperature detected by the third temperature sensor.

Preferably, when the temperature measured by the third temperature sensor is lower than a certain temperature, the central controller controls the valve 5 to increase the opening degree, and at the same time controls the valve 17 to reduce the opening degree, so as to increase the flue gas entering the air preheater 1 traffic. When the temperature measured by the third temperature sensor is higher than a certain temperature, the central controller controls the valve 5 to reduce the opening degree, and simultaneously controls the valve 17 to increase the opening degree to reduce the flow of air entering the air preheater 1 .

When the temperature measured by the third temperature sensor is lower than a certain temperature, the ability of the air preheater 1 to preheat the air will become worse and cannot meet the normal demand, so more flue gas is needed to heat the air preheater , thereby preheating the air.

Through the above operation, when the flue gas temperature is high, after meeting the demand for preheated air, the excess heat can be stored through the heat storage device, and when the flue gas temperature is low, more flue gas can be The air enters the air preheater to preheat the air, which ensures the demand for preheated air and saves energy at the same time.

(5) Control the opening and closing of the valve according to the flue gas temperature

Preferably, a fourth temperature sensor is provided in the flue 14 upstream of the upstream valve 6, and the fourth temperature sensor is used to detect the flue gas temperature in the flue. The fourth temperature sensor is in data connection with the central controller, and the central controller controls the opening and closing of the upstream valve 6 and the downstream valve 7 according to the data detected by the fourth temperature sensor.

When the central controller detects that the temperature of the flue 14 exceeds a certain temperature, for example, the boiler starts to discharge high-temperature flue gas when it is running, the central controller controls the upstream valve 6 and the downstream valve 7 to be open, and the flue gas can enter the air pre-heater. Heater 1 and heat storage device 2 are exhausted after the heat exchange is completed. When the central controller detects that the flue gas temperature in the flue 14 is lower than a certain temperature, such as when the boiler stops running, or the flue gas temperature is low due to the use of waste heat in the front, in order to avoid low-temperature corrosion or the waste heat cannot be used, the central control The controller controls the upstream valve 6 and the downstream valve 7 to close, and the pipeline where the air preheater 1 and the heat storage 2 are located forms a circulation pipeline. At this time, the heat stored in the heat accumulator 2 is used to heat the air preheater 1 to preheat the air. Through the above-mentioned operation, when the flue gas temperature meets the requirements and the amount of preheated air generated by the air preheater 1 is satisfied, excess heat can be stored in the heat storage device 2, and when there is no smoke In the case of waste gas heat, the heat stored in the waste heat of the flue gas is used to heat the air preheater 1 to meet the actual working requirements of the air preheater 1 . In this way, the residual heat of the flue gas can be fully utilized to avoid excessive waste of heat.

Preferably, when the smoke sensor detects that the temperature exceeds a certain level, the central controller controls the bypass valve 15 to close, and the upstream valve 6 and the downstream valve 7 to open.

Preferably, when the smoke sensor detects that the temperature is lower than a certain temperature, the central controller controls the bypass valve 15 to open, and the upstream valve 6 and the downstream valve 7 to close.

(6) Control the operation of the fan in the closed circulation system according to the flue gas flow

This embodiment is an improvement on the basis of the (fifth) embodiment.

As a preference, a fan is installed on the secondary pipeline 13, and when the flue gas temperature in the pipeline 14 is lower than a certain value, the pipeline where the air preheater 1 and the heat storage 2 are located forms a circulation pipeline through the operation of the fan.

Preferably, the fan is connected to the central controller for data, and the central controller 3 automatically controls the operation of the fan according to the data monitored by the flue sensor.

When the central controller detects that the flue gas temperature in the pipeline is higher than a certain temperature, the central controller controls the upstream valve 6 and the downstream valve 7 to open, and automatically controls the fan to stop running. Because the flue gas temperature at this time meets the heat exchange requirement, the flue gas can be used to heat the air preheater and the heat storage device 2 . When the central controller detects that the flue gas temperature in the pipeline is lower than a certain temperature, the central controller controls the upstream valve 6 and the downstream valve 7 to close, and the central controller automatically controls the fan to start running. Because the flue gas temperature at this time does not meet the heat exchange requirements, it is necessary to use the heat storage device 2 to heat the air preheater. By controlling the intelligent operation of the fan according to the flue gas temperature, the intelligent control of the fan operation can be realized according to the actual situation, which improves the intelligence of the system.

When the central controller detects that the flue gas temperature in the pipeline is higher than a certain temperature, the bypass valve is closed. When the central controller detects that the flue gas temperature in the pipeline is lower than a certain temperature, the bypass valve opens.

(7) Control the operation of the fan according to the temperature detection at the outlet of the heat storage device

Preferably, the outlet of the heat storage 2 is provided with a first temperature sensor for detecting the temperature of the gas at the outlet of the heat storage. The air preheater is provided with a second temperature sensor for detecting the temperature of the air in the air preheater 1 . The first temperature sensor and the second temperature sensor are in data connection with the central controller 3 . The central controller 3 automatically controls the operation of the fan according to the temperature detected by the first temperature sensor and the second temperature sensor.

If the temperature detected by the first temperature sensor is lower than the temperature detected by the second temperature sensor, the central controller 3 controls the fan to stop running.

When the upstream valve and downstream valve are closed, the operation of the fan is controlled by the detected temperature, and the air preheater can be automatically heated. Because it is found in the process of research and development and experiments that when the heat of the heat storage is gradually used up, the temperature of the gas coming out of the heat storage will be lower than the temperature of the air in the air preheater 1. In this case It is impossible to use the heat storage to heat the air preheater, but it may cause the heat of the air preheater to be taken away. Therefore, by intelligently controlling the operation of the fan according to the detected temperature, thereby intelligently controlling the circulation of the heat storage device 2 and the air preheater 1, and increasing the production rate of preheated air.

Although the present invention has been disclosed above with preferred embodiments, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, so the protection scope of the present invention should be based on the scope defined in the claims.

Claims (5)

1. a kind of station boiler afterheat utilizing system, the system comprises air preheater and thermal storage device, the air preheater It is arranged on the main pipeline of flue, the thermal storage device is arranged in secondary duct, and the main pipeline and secondary duct form parallel pipeline, Flue gas in flue respectively enters the air preheater and thermal storage device of main pipeline and secondary duct, and steaming is generated in air preheater Vapour carries out heat accumulation in thermal storage device, and the flue gas after exchanging heat in air preheater and thermal storage device converges again into flue；

The position of the entrance of the air preheater of flue collector is arranged in air preheater valve, enters air preheater for controlling Flue gas flow, the position of the inlet tube of the thermal storage device of secondary duct is arranged in thermal storage device valve, enters thermal storage device for controlling Flue gas flow, the system also includes central controller, the central controller and air preheater valve and thermal storage device Valve carries out data connection, and third temperature sensor is arranged at the position of the smoke inlet of air preheater, for measure into Enter the temperature of the flue gas of air preheater；Third temperature sensor and central controller carry out data connection, central controller root The valve opening of air preheater valve and thermal storage device valve is automatically controlled according to the temperature of third temperature sensor detection.

2. afterheat utilizing system as described in claim 1, which is characterized in that when the temperature of third temperature sensor measurement is lower than When certain temperature, central controller controls air preheater valve increases aperture, while controlling the reduction of thermal storage device valve Aperture, to increase the flow for the flue gas for entering air preheater；When the temperature of third temperature sensor measurement is higher than certain temperature When spending, central controller controls air preheater valve reduces aperture, while controlling thermal storage device valve and increasing aperture, to subtract Less into the flow of the flue gas of air preheater.

3. afterheat utilizing system as described in claim 1, which is characterized in that the air preheater includes that heat pipe, flue gas are logical Road and air duct, the heat pipe include evaporation ends and condensation end, and in the air passageway, evaporation ends are arranged for the condensation end setting In flue；Evaporation ends absorb the waste heat of flue gas in boiler flue, and the sky in air duct is transferred heat to by condensation end Gas, it is combustion-supporting that the air after preheating enters boiler furnace progress.

4. afterheat utilizing system as claimed in claim 3, which is characterized in that stabilising arrangement is set in the thermal-collecting tube, it is described Stabilising arrangement is laminated structure, and the laminated structure is arranged on the cross section of thermal-collecting tube；The stabilising arrangement is square logical Hole and octagon through-hole composition, the side length of the square through-hole are equal to the side length of octagon through-hole, and the square is logical Four of hole while be respectively four different octagon through-holes while, four of octagon through-hole apart from one another by side distinguish It is the side of four different square through-holes.

5. afterheat utilizing system as described in claim 1, which is characterized in that the cross section of thermal-collecting tube is square.