CN213515190U - Efficient anti-blocking pulverized coal heater - Google Patents

Abstract

The utility model relates to a firing equipment indicates a stifled coal powder heater is prevented to high efficiency very much contains pipe shaft, buggy inlet tube, buggy outlet pipe, heat source inlet tube, heat source outlet pipe, heat exchange module and transducer. The main body of the heat exchange module is sleeved in the tube body, and the two ends of the heat exchange module extend out of the tube body. The coal powder inlet pipe and the coal powder outlet pipe are respectively connected to two ends of the heat exchange module. Above the side of the tube body, a heat source inlet tube is arranged, and below the side of the tube body, a heat source outlet tube is arranged. One or more transducers are connected to the heat exchange module. The utility model discloses have that stand wear and tear energy is strong, heating module live time is long, ensure that the buggy can not stagnant flow and deposit in the heating process, prevent that the buggy deposit is effectual, improved heat exchange efficiency, design processing technology is simple moreover, makes things convenient for batch production.

Description

Efficient anti-blocking pulverized coal heater

Technical Field

The utility model relates to a firing equipment indicates a stifled buggy heater is prevented to high efficiency very much.

Background

The fuel for the boiler of the thermal power plant is formed by mixing coal powder through a pipeline and high-speed air to form coal powder airflow which is sent into a hearth for combustion, the coal powder airflow entering the boiler can reach an ignition temperature only by absorbing certain heat from an initial temperature to realize stable combustion, and the ignition temperature is called ignition heat of the coal powder airflow. The ignition heat of the pulverized coal airflow entering the boiler hearth is linearly reduced along with the increase of the initial temperature of the pulverized coal airflow. Obviously, if the pulverized coal airflow can be maintained at a higher temperature level when the boiler is started or under a low-load working condition, the ignition heat of the pulverized coal airflow can be greatly reduced, the ignition heat required by the pulverized coal entering the boiler is reduced, the mechanical and chemical incomplete combustion loss of the pulverized coal can be reduced, the combustion efficiency of the pulverized coal is improved, and the heat loss of smoke exhaust is reduced; the stable combustion characteristic of the boiler in a low-load state can be effectively improved, the combustion state of the boiler is improved, the peak regulation of a thermal power generating unit is greatly facilitated, and the boiler efficiency is improved; it is also beneficial to ensure the stable operation of the boiler when non-designed coal is used in the thermal power plant or other non-standard coal types with high ash content and high moisture coal quality are used.

At present, due to the change of boiler coal types of a thermal power plant and the limitation of a raw coal powder heating system, the current coal powder airflow temperature cannot meet the combustion requirement. The temperature of the pulverized coal airflow needs to be increased by adopting special heating equipment so as to achieve the purpose of reducing the ignition heat of the pulverized coal. Due to the particularity of the use environment and the operation condition of the pulverized coal heater, the heating device has the following problems:

1. the heat exchange surface is abraded in the coal powder heating process, and when the air-powder mixture flowing at high speed contacts the heat exchange surface, the impact and abrasion are generated on the heat exchange surface, so that the service life of the heater is influenced.

2. The heat exchange efficiency is low, the coal powder is generally heated by high-temperature steam through a heat exchange pipe to heat coal powder airflow, and the heat transfer coefficient of the coal powder airflow is less than 100 Wm-2-1.

3. The coal dust is seriously blocked in the heating process.

Among them, the coal dust is clogged for several reasons:

1. under the influence of raw coal components, coal contains a certain amount of mineral substances such as clay, carbonate, pyrite and the like. The content and the performance of clay minerals have great influence on coal caking property, and coal dust is easy to be stuck and blocked when the content is higher.

2. The smaller the average particle size of the pulverized coal is, the more fine powder is, the specific surface area is large, the surface free enthalpy is high, the surface energy is rapidly increased, the acting force between particles is large, the internal force is strong, so that the pulverized coal becomes an unstable thermodynamic system, the particles have the tendency of spontaneous aggregation to reduce the free enthalpy of the system, the particles gradually become larger to form secondary particles, and the macroscopic expression of the secondary particles is that the caking property of the pulverized coal is strong.

3. During the movement of the pulverized coal particles, the particle size, speed and temperature of the pulverized coal particles change along the track due to evaporation, volatilization, surface reaction, resistance and heat transfer.

4. Although the hot air dries the coal dust in the coal dust process, the coal dust is not completely dehydrated, and the coal dust flow capacities of different water content rates are different, mainly because of the action of liquid capillary force, water exists among particles in a liquid bridging mode, so that liquid bridging force is generated, and the particles have the tendency of being bonded with each other.

5. Studies have shown that fine-grained powders are decisive for the flowability of the coal dust particles, coarse particles are not very viscous without the fine particles adhering, and in particular the change in the amount of the grain constituents below 10 μm has a considerable influence on their flowability.

6. The coal dust particles are mutually collided and rubbed in motion, and the particles are positively charged in the collision and friction process between the particles and the wall surface of the pipeline; during the process of heating coal powder by hot air, some gaseous ions with charges contact with coal powder particles to cause the particles to have negative charges, thereby forming coal powder agglomeration.

Based on one or more reasons, the pulverized coal is very easy to deposit in the heat exchange tube in the heating process of the heater, so that the flow resistance is increased slightly, and the pulverized coal accumulation deflagration accident is caused seriously. At present, no ideal solution is provided for the problem of heating coal powder before entering the furnace.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a stifled buggy heater is prevented to high efficiency, through special structural design, can effectually solve buggy heating in-process heat-transfer surface wearing and tearing, heat exchange efficiency hang down and buggy heating in-process blocks up serious scheduling problem.

The utility model provides a high-efficiency anti-blocking pulverized coal heater, which is characterized by comprising a pipe body, a pulverized coal inlet pipe, a pulverized coal outlet pipe, a heat source inlet pipe, a heat source outlet pipe, a heat exchange module and a transducer; the main body of the heat exchange module is sleeved in the tube body, and the two ends of the heat exchange module extend out of the tube body; the pulverized coal inlet pipe and the pulverized coal outlet pipe are respectively connected to two ends of the heat exchange module; the heat source inlet pipe is arranged above the side edge of the pipe body; a heat source outlet pipe is arranged below the side edge of the pipe body; one or more of the transducers are connected to the heat exchange module.

Further, a plurality of sets of expansion pipes are arranged on the pipe body close to the heat source inlet pipe and surround the pipe body for one circle.

Furthermore, a splitter cone for guiding the high-speed pulverized coal airflow to be uniformly distributed is arranged inside the pulverized coal inlet pipe.

Furthermore, the heat exchange module is composed of a front tube plate, a rear tube plate and a plurality of straight round tubular heat exchange tubes fixed between the front tube plate and the rear tube plate.

One or more partition plates for guiding a heat source are further arranged between the front tube plate and the rear tube plate; and through holes for the heat exchange tubes to pass through are arranged on the partition plate.

Further, one or more water drainage ports are arranged at the bottom of the partition plate.

Further, a plurality of fins for improving heat exchange efficiency are arranged in the heat exchange tube; the single fin is sheet-shaped and is fixed on the inner wall of the heat exchange tube along the radial direction of the heat exchange tube; the plurality of fins are uniformly distributed along the circumferential direction.

Furthermore, a wear-resistant pipe is arranged at the high-speed pulverized coal airflow inlet end of each heat exchange pipe; the front end of the wear-resistant pipe is a bell mouth, the middle and rear ends of the wear-resistant pipe are in a straight round pipe shape, and the outer diameter of the middle and rear section round pipe is smaller than the inner diameter of the heat exchange pipe; the middle rear end of the wear-resistant pipe is inserted into and fixed in the heat exchange pipe.

Furthermore, a coarse concave thread is processed on the outer wall of the middle rear end of the wear-resistant pipe; the front end of the heat exchange tube is provided with a part inserted corresponding to the wear-resistant tube, and the inner wall of the heat exchange tube is provided with a rough concave thread corresponding to the thread on the outer wall of the wear-resistant tube; and a spiral high-temperature resistant strip is arranged in a gap formed by the wear-resistant pipe and the coarse concave thread on the heat exchange pipe.

The utility model discloses a stifled pulverized coal heater is prevented to high efficiency compares with prior art, and it is showing characteristics and has:

1. the ceramic wear-resistant pipe is adopted at the inlet end of the heat exchange pipe, so that the wear-resistant energy is strong, and the service time of the heater is ensured.

2. The ultrasonic transducer is arranged on the tube plate, so that metal particles of the heat exchange tube keep high-frequency elliptical motion all the time, the coal powder is ensured not to stagnate and deposit in the heating process, and the effect of preventing the coal powder from depositing is good.

3. Fins are arranged inside the heat exchange tube, so that the heat transfer area is increased; in addition, through the high-frequency fluctuation of the heat exchange pipe wall, the thermal resistance of the viscous flow layer is damaged, the disturbance inside and outside the heat exchange pipe is increased, and the heat exchange efficiency is improved.

4, the utility model discloses a heater and ordinary shell and tube type heat exchanger are unanimous basically in the aspect of design and processing technology, and wear-resisting ceramic pipe and heat exchange tube adopt the screw thread form to connect, do not need special technology, also need not to change conventional heater structural design, and design processing technology is simple, convenient batch production.

Drawings

Fig. 1 is a schematic overall structure diagram of a preferred embodiment of the high-efficiency anti-blocking pulverized coal heater of the present invention;

fig. 2 is a schematic structural diagram of a heat exchange module according to a preferred embodiment of the high-efficiency anti-blocking pulverized coal heater of the present invention;

FIG. 3 is a schematic structural view of a wear-resistant tube and a heat exchange tube of a preferred embodiment of the high-efficiency anti-blocking pulverized coal heater of the present invention;

FIG. 4 is a schematic structural view of a wear-resistant tube of a preferred embodiment of the high-efficiency anti-blocking pulverized coal heater of the present invention;

FIG. 5 is a schematic view of the structure of the refractory strips of a preferred embodiment of the high efficiency anti-clogging pulverized coal heater of the present invention;

FIG. 6 is a detailed view of the inside of the heat exchange tube of a preferred embodiment of the high efficiency anti-clogging pulverized coal heater of the present invention;

fig. 7 is a schematic view of the fin structure of the heat exchange tube of a preferred embodiment of the high-efficiency anti-blocking pulverized coal heater of the present invention.

The heat exchanger comprises a pipe body 1, an expansion pipe 2, a pulverized coal inlet pipe 3, a pulverized coal outlet pipe 4, a shunting cone 5, a heat source inlet 6, a heat source outlet 7, an energy converter 8, a front pipe plate 9, a rear pipe plate 10, a heat exchange pipe 11, a partition plate 12, a wear-resistant pipe 13, a high-temperature resistant strip 14 and a fin 15.

Detailed Description

Specific embodiments of the present invention will be described below with reference to the accompanying drawings.

Examples

Referring to fig. 1, a preferred embodiment of a high-efficiency anti-blocking pulverized coal heater of the present invention includes a pipe body 1, an expansion pipe 2, a pulverized coal inlet pipe 3, a pulverized coal outlet pipe 4, a heat source inlet pipe 6, a heat source outlet pipe 7, a heat exchange module, and a transducer 8. A heat source inlet pipe 6 is provided at the upper right side of the pipe body 1, and a heat source outlet pipe 7 is provided at the lower left side of the pipe body 1. The heat source is steam and at the heat source inlet 6, the new steam pressure and temperature are high, so the inlet is generally arranged to be relatively large. At the heat source outlet 7, the input steam is cooled through the heat exchange module, and according to different designs, the steam can be low-temperature steam or condensed water, and the equipment connected with the outlet at the heat source outlet 7 is different accordingly. The heat source outlet 7 may be provided smaller if condensed water is discharged, and the heat source outlet 7 may be provided larger if low-temperature steam is discharged. The expansion pipes 2 surrounding the pipe body 1 for one circle are arranged on the pipe body close to the heat source inlet pipe 6 on the right side of the pipe body 1, are made of the same metal material, can resist corrosion, temperature and pressure, and are connected with the pipe body 1 by a welding method. The main body of the heat exchange module is sleeved in the tube body, and a front tube plate 9 positioned on the left side of the heat exchange module and a rear tube plate 10 positioned on the right side of the heat exchange module extend out of two ends of the tube body and are fixed on the tube body 1 in a welding mode. The coal powder inlet pipe 3 is fixed on the front pipe plate 9, and a shunting cone 5 for guiding high-speed coal powder airflow to be uniformly distributed is arranged in the coal powder inlet pipe 3. The pulverized coal outlet pipe 4 is fixed to the rear tube plate 10. The transducers 8 are welded to the front 9 and rear 10 tube sheet arrangements. The number of transducers 8 is selected according to the size of the heat exchange module and the degree of pipe blockage.

Referring to fig. 2, the heat exchange module is composed of a front tube plate, a rear tube plate, and a plurality of straight round tubular heat exchange tubes fixed between the front tube plate and the rear tube plate. Round holes corresponding to the number and the outer diameter of the heat exchange tubes 11 are processed on the front tube plate 9 and the rear tube plate 10 and used for installing the heat exchange tubes 11. And a heat exchange tube 11 is arranged on each round hole, and two ends of each heat exchange tube 11 are respectively fixed on the front tube plate 9 and the rear tube plate 10 by adopting strength welding and strength expansion joint processes to form a heat exchange tube bundle in the heat exchange module. A baffle 12 is provided at a suitable position in the middle of the bundle for directing the steam entering the heater. The partition plate 12 is provided with a through hole for the heat exchange tube to pass through, and can also play a role in fixing the heat exchange tube 11 in the heat exchange tube bundle. When the steam temperature as the heat source is discharged in the form of condensed water, in order to prevent the condensed water from collecting between the partition plates, a plurality of drain ports are provided at the bottom of the partition plate 12 to facilitate the discharge of the condensed water. The front tube plate 9 and the rear tube plate 10 are made of metal materials which are corrosion-resistant, high in elastic coefficient and easy to weld. The heat exchange tube 11 is made of a metal material which is corrosion-resistant, has a high elastic coefficient and is easy to weld and expand.

Referring to fig. 3, 4, 5, 6 and 7, a wear-resistant pipe 13 is disposed at the high-speed pulverized coal stream inlet end of the heat exchange pipe 11. The wear-resistant pipe 13 is made of a ceramic material having high hardness, a small friction coefficient, and wear resistance. The front end of the wear-resistant pipe 13 is a horn mouth, the middle and rear ends are straight round pipes, and the outer diameter of the middle and rear round pipes is smaller than the inner diameter of the heat exchange pipe 11. The front end bell mouth of the wear-resistant pipe 13 is an inlet end and faces to the direction of high-speed pulverized coal airflow movement, and the middle rear end of the wear-resistant pipe 13 is inserted into and fixed in the heat exchange pipe 11. The outer wall of the rear section circular tube of the wear-resistant tube 13 is provided with a rough concave thread. A coarse concave thread corresponding to the thread on the outer wall of the rear round tube of the wear-resistant tube 13 is processed on the part inserted corresponding to the wear-resistant tube 13 in the left end of the heat exchange tube 11. Other parts of the heat exchange tube 11 are provided with fins 15. The fin 15 is a plate shape and is fixed to the inner wall of the heat exchange tube 11 in the radial direction of the heat exchange tube 11. The plurality of fins 15 are uniformly distributed along the circumferential direction.

Depending on the nature of the on-site heating of the pulverized coal, it may be necessary to provide an abrasion resistant coating on the inside of the heat exchange tube 11 to improve the operation time. Between the wear resistant tube 13 and the heat exchange tube 11, a high temperature resistant strip 14 is provided. The high temperature resistant strips 14 are spiral and correspond to the thick concave threads on the wear-resistant pipe 13 and the heat exchange pipe 11. The round tube part of the wear-resistant tube 13 is arranged at the left side of the heat exchange tube 11, and before installation, the high-temperature resistant strip 14 is wound on the thick concave thread at the round tube part of the wear-resistant tube 13, and is adhered to two ends by high-temperature resistant glue and then screwed into the heat exchange tube 11. At this time, the high temperature resistant strip 14 is embedded in the gap composed of the wear resistant pipe 13 and the coarse female thread on the heat exchange pipe 11, filling and sealing the gap. Therefore, the flexible connection between the wear-resistant pipe 13 and the heat exchange pipe 11 is ensured, namely the wear-resistant pipe 13 is ensured not to fall off in the operation process of the heat exchanger, and simultaneously the vibration of the heat exchange pipe 11 is ensured not to be directly transmitted to the wear-resistant pipe 13, so that the wear-resistant pipe 13 is ensured not to be damaged by vibration.

Referring to fig. 1, 2 and 3, in the actual operation process, the front part of the heat exchange tube 11 has a high air speed and a high friction ratio, i.e. the abrasion problem is dominant and the coal dust deposition and blockage problem is light; the problem of coal dust deposition and blockage is obvious under the actions of friction resistance, fine powder adhesion, charge attraction, thermophoretic force and the like on the coal dust at the rear part of the heat exchange tube 11, and at the moment, effective measures must be taken to prevent the problem of coal dust deposition in the heat exchange tube 11.

The pulverized coal airflow to be heated enters the heater from the pulverized coal inlet pipe 3, and the shunting cone 5 is arranged inside the pulverized coal inlet pipe 3 to conduct certain diversion on the high-speed pulverized coal airflow, so that the pulverized coal airflow is uniformly distributed to the inlet of the heat exchange pipe 11, and the pulverized coal airflow is prevented from impacting the heat exchange pipe 11 positioned at the center.

The coal dust air flow enters the inlet of the heat exchange tube 11 and firstly contacts the bell-mouth part of the wear-resistant tube 13 at the front end of the heat exchange tube 11, and the bell-mouth part has larger area and plays the roles of guiding flow and protecting the tube plate. Then the pulverized coal airflow enters the straight pipe section part of the wear-resistant pipe 13. In the actual operation of the conventional pulverized coal heater, it was found that the high-speed pulverized coal stream is most severely damaged by friction at the stage of entering the inlet of the heat exchange tube 11. The utility model discloses in, the cover is equipped with before the heat exchange tube 11 and adopts wear-resisting and low surface energy's ceramic material to make wear-resisting pipe 13, and its abrasive resistance is higher than metal material far away, so the life of heat exchange tube entrance has been guaranteed in this design.

Because the wear-resistant pipe 13 is inserted into the heat exchange pipe 11, the inner diameter of the wear-resistant pipe is smaller than that of the wear-resistant pipe by more than 2mm, so that the high-speed pulverized coal airflow does not directly impact the inner wall of the heat exchange pipe 11 after leaving the wear-resistant pipe 13, but contacts the inner wall of the heat exchange pipe 11 at a very small angle after being rushed out for a certain distance, and in addition, the impact abrasion of the pulverized coal airflow on the inner wall of the heat exchange pipe 11 is greatly reduced due to the fact that the sectional area is enlarged and the pulverized coal flow velocity is reduced, and. The design solves the problems of abrasion in the middle of the heat exchange tube and short service time.

The coal dust airflow enters the rear part of the heat exchange tube 11, and the physical and chemical properties of the coal dust change to a certain extent along with the increase of the temperature, so that the coal dust is very easy to deposit and block in the heat exchange tube 11, the fluid resistance is increased, the coal dust flux is reduced, and the explosion of the coal dust can be caused to cause serious accidents in serious cases. The coal powder heating has the specific conditions of high temperature, large abrasion and the like in the operation process; the low surface energy coating which is commonly used in the heat exchange module at present and reduces the friction coefficient of the heat exchange wall surface cannot be used at all. In addition, the power plant boiler cannot be temporarily stopped during operation, and all equipment in the system must be kept in stable operation for a long time. Therefore, the utility model discloses in adopted power ultrasonic wave technique to thoroughly solve the problem of buggy deposit and jam, the high-efficient long-term steady operation of guarantee heater.

A plurality of transducers 8 are arranged on a front tube plate 9 and a rear tube plate 10 of the heat exchange module, receive power ultrasonic signals of a controller, convert electric energy into mechanical wave energy with the same frequency, and the energy is transmitted in the tube plates in the form of longitudinal waves, so that the front tube plate 9 and the rear tube plate 10 generate energy waves with high-frequency fluctuation of about 5 microns. Each heat exchange tube 11, the front tube plate 9 and the rear tube plate 10 of the heat exchange tube bundle in the heat exchange module are connected in a strength welding and strength expansion mode, so that energy waves from the transducer 8 can be transmitted to each heat exchange tube 11, micron-sized fluctuation with the same frequency as the transducer 8 can be generated in the heat exchange tubes 11, the fluctuation is actually the result of elliptical motion generated by metal particles on the surfaces of the heat exchange tubes, and the elliptical motion of the metal particles can be decomposed into component force in the horizontal direction of the axis of a pipeline and component force in the vertical direction of the axis of the pipeline. The horizontal component force has good stripping capability on the pulverized coal, the vertical component force has good conveying capability on the pulverized coal, both the horizontal component force and the vertical component force have good capability of preventing the pulverized coal from depositing, and the pulverized coal is always ensured not to stay at any position in the heat exchange tube 11 in the heating process, so that the problems of sedimentation and blockage of the pulverized coal are avoided.

In addition, the arrangement of the transducer 8 also has the function of enhancing heat transfer. The elliptic motion of the metal particles on the surface of the heat exchange tube 11 can break or reduce a stagnant layer between the pulverized coal airflow and the inner wall of the heat exchange tube 11, reduce the frictional resistance, insulate heat and increase disturbance, thereby enhancing the heat exchange effect. For the outer wall of the heat exchange tube 11, the stagnant layer between the steam and the heat exchange tube wall can be reduced or destroyed, especially under the condition of condensation heat exchange, the film-shaped condensation heat exchange can be effectively converted into the bead-shaped condensation heat exchange, and the heat transfer efficiency can be improved by more than dozens of times.

The heat exchange tube 11, the front tube plate 9 and the rear tube plate 10 are driven by the transducer 8 to carry out micron high-frequency fluctuation, which belongs to the elastic fluctuation range of metal and cannot cause any damage to a heating system. In order to ensure that the wear-resistant pipe 13 is not damaged by the high-frequency fluctuation of the heat exchange pipe 11, the wear-resistant pipe 13 and the heat exchange pipe 11 are connected and isolated in a threaded manner by adopting the high-temperature resistant strip 14, so that the wear-resistant pipe 13 is ensured not to fall off in the operation process, and the high-frequency fluctuation of the heat exchange pipe 11 is ensured not to be transmitted to the upper surface of the wear-resistant pipe 13, thereby ensuring the service time of the wear-resistant pipe 13.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. All equivalent changes and modifications made according to the content of the claims of the present invention shall fall within the technical scope of the present invention.

Claims (9)

1. A high-efficiency anti-blocking coal powder heater is characterized by comprising a pipe body, a coal powder inlet pipe, a coal powder outlet pipe, a heat source inlet pipe, a heat source outlet pipe, a heat exchange module and a transducer; the main body of the heat exchange module is sleeved in the tube body, and the two ends of the heat exchange module extend out of the tube body; the pulverized coal inlet pipe and the pulverized coal outlet pipe are respectively connected to two ends of the heat exchange module; the heat source inlet pipe is arranged above the side edge of the pipe body; a heat source outlet pipe is arranged below the side edge of the pipe body; one or more of the transducers are connected to the heat exchange module.

2. A high efficiency blockage-preventing pulverized coal heater as defined in claim 1, wherein a plurality of groups of expansion pipes are arranged around the circumference of said pipe body near said heat source inlet pipe.

3. A high efficiency blockage-preventing pulverized coal heater as defined in claim 1, wherein a splitter cone for guiding high speed pulverized coal flow to be uniformly distributed is disposed inside said pulverized coal inlet pipe.

4. A high efficiency anti-clogging pulverized coal heater as defined in claim 1, wherein the heat exchange module is composed of a front tube plate, a rear tube plate and a plurality of straight round tubular heat exchange tubes fixed between said front tube plate and said rear tube plate.

5. A high efficiency anti-clogging pulverized coal heater as claimed in claim 4, wherein one or more baffles for guiding the heat source are further disposed between said front tube plate and said rear tube plate; and through holes for the heat exchange tubes to pass through are arranged on the partition plate.

6. A high efficiency anti-clogging pulverized coal heater as defined in claim 5, wherein one or more drain ports are provided at the bottom of said partition.

7. A high-efficiency anti-blocking pulverized coal heater as claimed in claim 4, wherein a plurality of fins for improving heat exchange efficiency are provided inside the heat exchange tube; the single fin is sheet-shaped and is fixed on the inner wall of the heat exchange tube along the radial direction of the heat exchange tube; the plurality of fins are uniformly distributed along the circumferential direction.

8. A high-efficiency anti-blocking coal dust heater as claimed in claim 4, wherein a wear-resistant pipe is arranged at the high-speed coal dust airflow inlet end of each heat exchange pipe; the front end of the wear-resistant pipe is a bell mouth, the middle and rear ends of the wear-resistant pipe are in a straight round pipe shape, and the outer diameter of the middle and rear section round pipe is smaller than the inner diameter of the heat exchange pipe; the middle rear end of the wear-resistant pipe is inserted into and fixed in the heat exchange pipe.

9. A high-efficiency anti-blocking pulverized coal heater as claimed in claim 8, wherein the outer wall of the middle rear end of the wear-resistant pipe is provided with a coarse concave thread; the front end of the heat exchange tube is provided with a part inserted corresponding to the wear-resistant tube, and the inner wall of the heat exchange tube is provided with a rough concave thread corresponding to the thread on the outer wall of the wear-resistant tube; and a spiral high-temperature resistant strip is arranged in a gap formed by the wear-resistant pipe and the coarse concave thread on the heat exchange pipe.

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