CN104534450B - A comprehensive utilization device for flue gas waste heat in a thermal power plant - Google Patents

Abstract

The invention provides a comprehensive utilization device for flue gas waste heat of a thermal power plant, which comprises an air preheater, a first-stage heat exchanger, a condensate water device, an absorption refrigerator, an electric dust removal device, a second-stage heat exchanger, a desulfurization device and a chimney, wherein the air preheater is connected with the first-stage heat exchanger; the air preheater, the electric dust removal device, the desulfurization device and the chimney are sequentially connected in series through pipelines; a first-stage heat exchanger is additionally arranged between the air preheater and the electric dust removal device and is used for reducing the temperature of the flue gas discharged by the air preheater, exchanging the high-temperature flue gas with cold water and then conveying the heated water to a condensate water device and an absorption refrigerator for reuse; the second-stage heat exchanger conveys the heat energy to the air preheater again to be recycled, so that energy waste is prevented. The invention adds the first-stage heat exchanger and the second-stage heat exchanger, can reduce the temperature of the discharged flue gas and prevent the flue gas from polluting the air.

Description

A comprehensive utilization device for flue gas waste heat in a thermal power plant

technical field

The invention belongs to the technical field of thermal power plants, and in particular, the invention particularly relates to a comprehensive utilization device for waste heat of flue gas in thermal power plants.

Background technique

Thermal power plants use the heat generated by the combustion of fuel such as coal to heat water into steam, and the pressure of the steam drives a steam turbine to do work to generate electricity.

However, in the process of thermal power generation, the flue gas released by fuel combustion contains harmful substances such as dust, carbon dioxide, sulfur oxides, carbon oxides, mercury and their compounds. Directly discharging the flue gas not only pollutes the atmosphere, but also brings harm to people's health. It may also cause acid rain, photochemical smog, ozone hole, greenhouse effect and other phenomena, further threatening the environment for human survival. Furthermore, the country has put forward new requirements for energy conservation. It is increasingly urgent to improve the thermal efficiency of boilers. One of the most effective ways is to use the waste heat from boiler exhaust. According to relevant data, due to changes in the original design of the boiler and the type of coal used, the thermal efficiency of a general industrial boiler is about 60% to 70%, and its exhaust gas temperature is about 250 to 350°C, while the heat conduction oil furnace, The exhaust gas temperature is even higher than 280°C, and a large amount of waste heat is not fully utilized, which greatly wastes energy.

From the above analysis, it can be seen that the thermal power plant power generation process of the prior art has the following characteristics and defects:

1. Discharging the flue gas released by the existing thermal power plants directly into the air will cause the temperature to rise and cause pollution to the environment.

2. At present, the flue gas released by thermal power plants is directly discharged into the air, resulting in a large amount of waste heat not being fully utilized, which greatly wastes energy.

Therefore, reducing the boiler flue gas temperature has become an important way for boiler energy saving.

Contents of the invention

The object of the present invention is to provide a comprehensive utilization device for waste heat of flue gas in a thermal power plant, so as to at least solve the problems of environmental pollution in the prior art, and further solve the problems of wasting resources in the prior art.

In order to solve the above problems, the present invention provides a thermal power plant flue gas waste heat comprehensive utilization device, and its technical scheme is as follows:

A comprehensive utilization device for flue gas waste heat in a thermal power plant, comprising: an air preheater, a first-stage heat exchanger, a condensation water device, an absorption refrigerator, an electric dust removal device, a desulfurization device and a chimney; the flue gas is produced by the air The flue gas inlet end of the preheater enters the air preheater, and the flue gas outlet end of the air preheater communicates with the first circuit inlet end of the first stage heat exchanger through a pipeline; The outlet end of the first circuit of the first-stage heat exchanger is connected with the inlet end of the electrostatic precipitator through a pipeline; the outlet end of the electrostatic precipitator is connected with the inlet end of the desulfurization device through a pipeline; The outlet end of the desulfurization device is connected to the chimney through a pipeline; the outlet end of the second circuit of the first-stage heat exchanger is connected with the inlet end of the condensate device through a pipeline; the condensate device The outlet end of the first stage heat exchanger is connected with the inlet end of the second circuit through the pipeline; the outlet end of the third circuit of the first stage heat exchanger is connected with the inlet end of the absorption refrigerator through the pipe The outlet end of the absorption refrigerating machine is connected with the inlet end of the third circuit of the first-stage heat exchanger through a pipeline.

Preferably, in the thermal power plant flue gas waste heat comprehensive utilization device, it also includes: a second-stage heat exchanger, the inlet end of the second-stage heat exchanger is connected to the outlet end of the electrostatic precipitator through a pipeline through; the outlet end of the second-stage heat exchanger is connected with the inlet end of the desulfurization device through a pipeline.

Preferably, in the thermal power plant flue gas waste heat comprehensive utilization device, the second-stage heat exchanger is also provided with a cold air inlet port and a hot air outlet port, and a hot air outlet port is also provided on the air preheater. The return port; the cold air inlet port of the second-stage heat exchanger communicates with the atmosphere; the hot air outlet port of the second-stage heat exchanger and the hot air return port of the air preheater pass through the pipeline connected.

Preferably, in the thermal power plant flue gas waste heat comprehensive utilization device, the flue gas channel inlet section connected to the first circuit inlet end of the first stage heat exchanger is a gradually expanding bell mouth structure, and the The outlet section of the flue gas channel connected to the outlet end of the first circuit of the first stage heat exchanger has a tapered bell mouth structure, so that the flow cross-sectional area of the flue gas channel in the first stage heat exchanger remains unchanged.

Preferably, in the thermal power plant flue gas waste heat comprehensive utilization device, the flue gas channel inlet section connected to the inlet end of the second-stage heat exchanger is a gradually expanding bell-mouth structure, and the second-stage The outlet section of the flue gas channel connected to the outlet end of the heat exchanger is a tapered bell-mouth structure, so that the cross-sectional area of the flue gas flow in the second-stage heat exchanger remains unchanged.

Preferably, in the thermal power plant flue gas waste heat comprehensive utilization device, it also includes: a support member, the support member is arranged between the intake section of the flue gas channel and the inlet end of the first circuit, while the A support member is also arranged between the outlet section of the flue gas channel and the outlet end of the first circuit, and is used to provide fixed support for the first-stage heat exchanger.

Preferably, in the thermal power plant flue gas waste heat comprehensive utilization device, it also includes: a wear plate installed on the windward side of the front heat exchange tube of the first stage heat exchanger for Play the role of anti-wear.

Preferably, in the thermal power plant flue gas waste heat comprehensive utilization device, it further includes: two pressure dynamometers, and one of the pressure dynamometers is installed on the flue gas channel at the front of the first-stage heat exchanger , used to measure the flue gas pressure that does not enter the first stage heat exchanger, and the other pressure gauge is installed on the flue gas channel at the rear of the first stage heat exchanger for measuring the The flue gas pressure discharged from the first stage heat exchanger; and the shock wave soot blower installed in the first stage heat exchanger, when the pressure difference between the two pressure dynamometers When it is greater than 400Pa, start the shock wave sootblower for sootblowing treatment.

Preferably, in the thermal power plant flue gas waste heat comprehensive utilization device, there are multiple shock wave sootblowers, which are the same as the number of rows of heat exchange tubes in the first-stage heat exchanger, and are respectively installed in the One side of each row of heat exchange tubes of the first stage heat exchanger is used to blow off the soot on the row of heat exchange tubes.

Preferably, in the thermal power plant flue gas waste heat comprehensive utilization device, the heat exchange tubes of the second stage heat exchanger are glass tubes or ceramic tubes.

It can be seen from the analysis that compared with the prior art, the present invention first increases the first-stage heat exchanger and the second-stage heat exchanger to reduce the temperature of the exhausted flue gas and prevent the flue gas from polluting the air. Furthermore, the present invention uses the thermal energy of the first-stage heat exchanger for the condensation water device and the absorption refrigerator, so that the thermal energy in the flue gas can be fully utilized again and energy waste is prevented. In the present invention, the thermal energy of the second-stage heat exchanger is sent back to the air preheater, and the temperature of the secondary air entering the air preheater is increased, so that the amount of steam used by the conventional air heater can be reduced, and the combustion effect of the boiler can be enhanced; Furthermore, the flue gas temperature at the flue gas outlet end can be increased to provide conditions for further utilization of the waste heat of the flue gas.

Description of drawings

Fig. 1 is a schematic structural diagram of a preferred embodiment of the present invention.

Fig. 2 is a schematic diagram of the assembly structure of the first-stage heat exchanger, the inlet end of the first loop, and the outlet end of the first loop in a preferred embodiment of the present invention.

1-air preheater; 11-flue gas inlet; 12-flue gas outlet; 13-hot air return port; 2-first-stage heat exchanger; 21-first loop inlet; 22-first 23-the outlet of the second circuit; 24-the inlet of the second circuit; 25-the outlet of the third circuit; 26-the inlet of the third circuit; 27-the inlet section of the smoke channel; 28-the smoke channel Outlet section; 3-condensed water device; 31-inlet port; 32-exit port; 4-absorption refrigerator; 41-inlet port; 42-export port; 5-electric dust removal device; 51-inlet port; 52-export 6-second stage heat exchanger; 61-inlet port; 62-outlet port; 63-cold air inlet port; 64-hot air outlet port; 7-desulfurization device; 71-inlet port; 72-export port.

detailed description

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

As shown in Figure 1, the thermal power plant flue gas waste heat comprehensive utilization device of the preferred embodiment of the present invention mainly includes an air preheater 1, a first-stage heat exchanger 2, a condensation water device 3, an absorption refrigerator 4, and an electric dust removal device 5. Desulfurization device 7 and chimney.

The air preheater 1 and the first stage heat exchanger 2 use the heat of the flue gas to heat the fluid entering their respective interiors. The air preheater 1 , the electric precipitator 5 , and the desulfurization device 7 are sequentially connected in series, and the first-stage heat exchanger 2 is arranged between the air preheater 1 and the electric precipitator 5 .

Specifically, the air preheater 1 is provided with a flue gas inlet port 11 and a flue gas outlet port 12. The fluid circulating in the air preheater 1 is air, and the flue gas passes through the flue gas inlet of the air preheater 1. The flue gas enters through port 11 and is discharged from the flue gas outlet port 12. During the second process, it exchanges heat with the air in the air preheater 1, so that the temperature of the air in it increases, the temperature of the flue gas decreases, and the air with high temperature is used for external use. , the temperature-reduced flue gas enters the first-stage heat exchanger 2 from the inlet port 21 of the first circuit to exchange heat with the fluid in the first-stage heat exchanger 2;

The first-stage heat exchanger 2 is used to recover the waste heat of the flue gas between the air preheater 1 and the electrostatic precipitator 5 to the fluid circulating in it for heat exchange, so that the recovered heat is combined with the condensate water device 3 and the absorption type The refrigerator 4 performs heat exchange; that is, the fluid in the first-stage heat exchanger 2 is cold water, and the outlet port 32 of the condensation water device 3 is connected to the second inlet port 24 of the first-stage heat exchanger 2 through a pipeline; The inlet port 31 of the condensed water device 3 communicates with the second circuit outlet port 23 of the first stage heat exchanger 2 through pipelines; the outlet port 42 of the absorption refrigerator 4 communicates with the third circuit port of the first stage heat exchanger 2 The inlet port 26 is connected through a pipeline, and the inlet port 41 of the absorption refrigerating machine 4 is connected with the outlet port 25 of the third circuit of the first-stage heat exchanger 2 through a pipeline; the flue gas recovered by the first-stage heat exchanger 2 The heat is used to heat the cold water in it, and the heated cold water is divided into two paths through the pipeline and sent to the condensed water device 3 and the absorption refrigerator 4 respectively; Condensed water, in order to achieve the effect of reducing heat recovery and air extraction of the power plant, and reducing the heat consumption rate of the unit; heating the thermal water in the absorption chiller 4 is used as the driving heat source of the absorption chiller 4, and the output of the absorption chiller 4 Cooling capacity is used to supply all cooling loads in the power plant, including centralized control buildings, guest houses, office buildings, etc.;

The outlet end 22 of the first circuit of the first-stage heat exchanger 2 is connected to the inlet end 51 of the electrostatic precipitator 5 through a pipeline, so that the first-stage heat exchanger 2 is transported to the flue gas of the electric precipitator 5 The temperature drops to about 110°C; thus, the temperature of the flue gas entering the electrostatic precipitator 5 decreases, which can improve the dust removal effect of the electrostatic precipitator 5 and effectively reduce the power consumption of the equipment. Then enter the desulfurization device 7 for desulfurization, and then discharge from the chimney.

In order to further reduce the flue gas temperature, a second-stage heat exchanger 6 can be provided between the electric precipitator 5 and the desulfurization device 7, specifically: the outlet end 52 of the electric precipitator 5 and the inlet of the second-stage heat exchanger 6 The end 61 is connected through the pipeline, the outlet end 62 of the second stage heat exchanger 6 is connected with the inlet end 71 of the desulfurization device 7 through the pipeline, and the outlet end 72 of the desulfurization device 7 is connected to the chimney.

In order to further utilize the waste heat in the flue gas, the second-stage heat exchanger 6 is provided with a cold air inlet port 63 and a hot air outlet port 64, and a hot air return port 13 is provided on the air preheater 1. Heat exchange between flue gas and air (that is, cold air from the cold air inlet port 63) is performed in the heat exchanger 6, and the hot air after heat exchange is delivered to the air preheater 1 through the hot air return port 13, Increase the temperature of the secondary air entering the air preheater 1, which can reduce the amount of steam used by conventional heaters and enhance the combustion effect of the boiler; moreover, the temperature of the flue gas at the flue gas outlet 12 can be increased to further increase the waste heat of the flue gas. Take advantage of the conditions provided.

In actual work, it is necessary to consider how to realize that the flow cross-sectional area in the flue gas channel (that is, the pipeline) at the installation position of the first stage heat exchanger 2 remains unchanged. In this case, the original flue gas channel must be made Appropriate changes are made to increase the geometric dimensions of this section of the flue gas passage. As shown in Figure 2, the means adopted in the present invention are: the inlet section 27 of the flue gas passage connected to the inlet end 21 of the first circuit is a gradually expanding bell mouth Structure, the outlet section 28 of the flue gas channel connected to the outlet end 22 of the first circuit is a tapered bell-mouth structure, so that the cross-sectional area of the flue gas channel in the first-stage heat exchanger 2 remains unchanged. The theory is that the inlet section 27 of the flue gas channel at the front end of the first-stage heat exchanger 2 adopts a gradually expanding bell mouth design, and the outlet section 28 of the flue gas channel at the rear end of the first-stage heat exchanger 2 adopts a gradually expanding bell mouth design. The contracted bell mouth design allows the first-stage heat exchanger 2 to be installed in the flue gas channel to ensure that the cross-sectional area of the flow remains unchanged. In the same way, the inlet section of the flue gas channel connected to the inlet port 61 of the present invention is a gradually expanding bell mouth structure, and the outlet section of the flue gas channel connected to the outlet end 62 is a tapered bell mouth structure, so that the second stage heat exchange The flue gas flow cross-sectional area in the device 6 is constant.

To install the first-stage heat exchanger 2 in the flue gas passage, it is necessary to consider how to make the newly added first-stage heat exchanger 2 stable and firm in the flue gas passage. Based on this, the present invention also includes support members, support members It is arranged between the inlet section 27 of the flue gas channel and the inlet end 21 of the first circuit, and the support is also arranged between the outlet section 28 of the flue gas channel and the outlet end 22 of the first circuit, for the first stage heat exchanger 2 provide fixed support. Similarly, in the present invention, a support is provided between the inlet end 61 and the inlet section of the flue gas channel, and a support is provided between the outlet end 62 and the outlet section of the flue gas channel, so as to provide a fixation for the second-stage heat exchanger 6 support.

In order to enable the first-stage heat exchanger 2 to better realize gas-liquid heat exchange (that is, heat exchange between the flue gas in the flue gas channel and the liquid in the condensate water device 3 and the absorption refrigerator 4), and to prevent The flue gas causes damage to the structure of the first-stage heat exchanger 2, and the present invention also includes a wear-resistant plate (not shown), which is installed on the windward side of the front-end heat exchange tube of the first-stage heat exchanger 2, Used to prevent wear. It is further preferred to install wear-resistant plates on the windward surfaces of the three rows of heat exchange tubes at the front end of the first stage heat exchanger 2 .

The first-stage heat exchanger 2 of the present invention realizes gas-liquid heat exchange. Since the soot is carried in the flue gas, the soot will adhere to the heat exchanger of the first-stage heat exchanger 2 when passing through the first-stage heat exchanger 2. On the heat pipe, this will reduce the quality of gas-liquid heat exchange. In order to ensure the heat exchange quality, the present invention needs to consider how to remove the soot adhering to the heat exchange tube and the soot adhering to the inner wall of the first stage heat exchanger 2. Dispose of it, based on this, the present invention also includes two pressure dynamometers, one pressure dynamometer is installed on the flue gas channel at the front of the first stage heat exchanger 2, and is used for measuring 2 flue gas pressure, another pressure gauge is installed on the flue gas channel at the rear of the first stage heat exchanger 2 to measure the flue gas pressure discharged from the first stage heat exchanger 2; and shock wave soot blowing device (not shown), the shock wave soot blower is installed in the first-stage heat exchanger 2, and when the pressure difference between the two pressure gauges is greater than 400Pa, it proves that the first-stage heat exchanger 2 has Soot accumulation requires soot blowing. At this time, start the shock wave soot blower for soot blowing. In order to improve the quality of soot blowing, there are multiple shock wave soot blowers in the present invention. One side of each row of heat exchange tubes of the heater 2 is used to blow off soot on the row of heat exchange tubes.

Different from the gas-liquid heat exchange of the first-stage heat exchanger 2, the gas-gas heat exchange performed by the second-stage heat exchanger 6, the specific heat capacity of the flue gas in the second-stage heat exchanger 6 is not much different from the specific heat capacity of the air, which is much smaller than The difference between the specific heat capacity of the flue gas and the specific heat capacity of the liquid (that is, the working medium water in the condensing water device 3 and the absorption refrigerator 4), so the heat exchange area and volume in the second-stage heat exchanger 6 are large enough to realize the heat exchange heat; but the second-stage heat exchanger 6 directly borrows the cold air from the external environment. In this case, it is necessary to consider how to solve the anti-corrosion problem of the cold air. Based on this, the heat exchange tubes of the second-stage heat exchanger 6 of the present invention Choose glass tube or ceramic tube to make full use of the corrosion resistance stability of glass tube and ceramic tube. Furthermore, the flue gas temperature should not be lowered too much, on the premise of meeting the needs of subsequent desulfurization, it is more appropriate to lower the temperature to 50°C-70°C, and the optimum temperature is 70°C (that is, the outlet of the second-stage heat exchanger 6 after heat exchange) The temperature of the exhausted flue gas at end 62 is 70°C); the temperature is reduced to the temperature required by the desulfurization device 7, if the temperature is higher than the flue gas inlet temperature required by the desulfurization device 7, it is necessary to continue to spray water to cool down, wasting water. If the temperature is lower than the flue gas inlet temperature required by the desulfurization device 7, the desulfurization effect will be affected. The control of the flue gas temperature can be realized by the flow rate and bypass volume of the cold air entering the second-stage heat exchanger 6. When the temperature of the flue gas is low, the amount of cold air entering the second-stage heat exchanger 6 is reduced, Bypass capacity; on the contrary, increase the amount of cold air entering the second-stage heat exchanger and reduce the bypass capacity.

In this preferred embodiment, two-stage heat exchangers are used, and the heated water and hot air obtained by the heat exchangers are reused, which saves costs and prevents pollution to the environment.

In summary, the present invention can achieve the following beneficial effects:

1. Reduce boiler exhaust gas temperature and improve boiler efficiency;

2. Increase the temperature of the secondary air entering the boiler and improve the combustion efficiency of the boiler;

3. Reduce the temperature of the flue gas entering the electrostatic precipitator 5, improve the use efficiency of the electrostatic precipitator 5, and reduce the power consumption of the electrostatic precipitator 5;

4. By extracting part of the cold water and flue gas to exchange heat, stick to the amount of steam extracted in the condensate water device 3 (ie, the heat recovery system of the power plant), and reduce the heat consumption rate of the power plant; use the waste heat of the flue gas as the driving heat source of the absorption refrigerator 4 , the cooling capacity output by the absorption refrigerating machine 4 is used to supply all cooling loads in the power plant, reducing the power consumption rate of the power plant.

It can be known from common technical knowledge that the present invention can be realized through other embodiments without departing from its spirit or essential features. Accordingly, the above-disclosed embodiments are, in all respects, illustrative and not exclusive. All changes within the scope of the present invention or within the scope equivalent to the present invention are embraced by the present invention.

Claims (7)

1. a coal steam-electric plant smoke comprehensive waste-heat utilizing device, it is characterised in that: include air preheater, First order heat exchanger, condensate water device, Absorption Refrigerator, electric dust collector, desulfurizer and chimney；

Flue gas is entered in described air preheater by the gas approach end of described air preheater, described air The smoke outlet of preheater is connected by pipeline with the first circuit inlet end of described first order heat exchanger Logical；First circuit outlet end of described first order heat exchanger and the entrance point of described electric dust collector are by pipe Road is connected；The port of export of described electric dust collector is connected by pipeline with the entrance point of described desulfurizer Logical；The port of export of described desulfurizer is by pipeline connection to described chimney；

The exhaust gases passes air inlet section being connected with the first circuit inlet end of described first order heat exchanger is gradual-enlargement type Bell-mouth structure of air, the exhaust gases passes air outlet section being connected with the first circuit outlet end of described first order heat exchanger For tapering type bell-mouth structure of air, the actual internal area making exhaust gases passes in described first order heat exchanger is constant；

The second servo loop port of export of described first order heat exchanger and the entrance point of described condensate water device are by pipe Road is connected；The port of export of described condensate water device and the second servo loop entrance point of described first order heat exchanger It is connected by pipeline；

The tertiary circuit port of export of described first order heat exchanger passes through with the entrance point of described Absorption Refrigerator Pipeline is connected；The port of export of described Absorption Refrigerator enters with the tertiary circuit of described first order heat exchanger Mouth end is connected by pipeline；

Also include: second level heat exchanger, the entrance point of described second level heat exchanger and described electric dust collector The port of export be connected by pipeline；The port of export of described second level heat exchanger enters with described desulfurizer Mouth end is connected by pipeline；

Also including: support member, described support member is arranged on described exhaust gases passes air inlet section and described first time Between the entrance point of road, the most described support member is additionally arranged at described exhaust gases passes air outlet section and described first time Between way outlet end, support for providing fixing to described first order heat exchanger.

Coal steam-electric plant smoke comprehensive waste-heat utilizing device the most according to claim 1, it is characterised in that:

Described second level heat exchanger is additionally provided with inlet of cold air end and hot air outlet end, pre-at described air It is additionally provided with hot-air on hot device to answer back end；

The inlet of cold air end of described second level heat exchanger communicates with air；The heat of described second level heat exchanger Air outlet slit end is answered back with the hot-air of described air preheater to hold and is connected by pipeline.

Coal steam-electric plant smoke comprehensive waste-heat utilizing device the most according to claim 1, it is characterised in that:

The exhaust gases passes air inlet section being connected with the entrance point of described second level heat exchanger is gradual-enlargement type horn mouth knot Structure, the exhaust gases passes air outlet section being connected with the port of export of described second level heat exchanger is tapering type horn mouth knot Structure, makes the flue gas actual internal area in the heat exchanger of the described second level constant.

Coal steam-electric plant smoke comprehensive waste-heat utilizing device the most according to claim 1, it is characterised in that Also include:

Wear strip, at the windward side of the front end heat exchanger tube that described wear strip is arranged on described first order heat exchanger, For playing anti-wear effect.

Coal steam-electric plant smoke comprehensive waste-heat utilizing device the most according to claim 1, it is characterised in that Also include:

Two pressure ergometers, a described pressure ergometer is arranged on described first order heat exchanger front portion On exhaust gases passes, for measuring the flue gas pressures being introduced into described first order heat exchanger, another described pressure Power ergometer is arranged on the exhaust gases passes at described first order heat exchanger rear portion, is used for measuring the described first order The flue gas pressures that heat exchanger is discharged；With

Shock wave soot blower, described shock wave soot blower is arranged in first order heat exchanger, when two described pressure When pressure differential between ergometer is more than 400Pa, starts described shock wave soot blower and carry out soot blowing process.

Coal steam-electric plant smoke comprehensive waste-heat utilizing device the most according to claim 5, it is characterised in that:

Described shock wave soot blower is multiple, identical with the row of heat exchanger tube in described first order heat exchanger, point It is not arranged on the side often arranging heat exchanger tube of described first order heat exchanger, for by flue dust on this row's heat exchanger tube Blow off.

Coal steam-electric plant smoke comprehensive waste-heat utilizing device the most according to claim 1, it is characterised in that:

The heat exchanger tube of described second level heat exchanger is glass tubing or earthenware.