CN104964572A - Product waste heat ring-shaped partition-type recovery system and method for pellet calcining rotary kiln - Google Patents

Abstract

The invention discloses an annular partition wall recovery system and method for waste heat of rotary kiln products calcined with pellets, and belongs to the technical field of waste heat recovery of rotary kiln products. The recovery system of the present invention includes an annular partition wall heat exchange mechanism and an air supply pipe heat exchange mechanism. Both the high-temperature section cover and the medium-temperature section cover are cylinders with openings at both ends. The inner diameters of the high-temperature section cover and the medium-temperature section cover are both larger than the outer diameter of the cooling cylinder. The section cover is covered on the middle temperature section. The air supply pipe heat exchange mechanism includes the air supply pipe. The air supply pipe includes the air supply pipe insulation section and the air supply pipe heating section. The feed port of the cylinder and the outlet end of the heating section of the air supply pipe are connected with the air inlet of the burner through the pipe. The invention realizes the goals of improving the waste heat utilization efficiency of the rotary kiln, reducing cooling water consumption, reducing the probability of cooling equipment being corroded and improving the operating environment.

Description

A ring-shaped partition wall recovery system and method for waste heat of rotary kiln products calcined with pellets

technical field

The invention relates to the technical field of waste heat recovery of rotary kiln products, and more specifically relates to an annular partition wall recovery system and method for waste heat of rotary kiln products calcined with pellets.

Background technique

Rotary kiln calcination is the main process for the production of bioceramic filter materials. Its function is to dry and sinter the raw materials (that is, spherical particles made of clay and fly ash) produced by filter materials. Among them, the drying section is used to eliminate The moisture contained in the ceramic filter material, the sintering section is calcined to make the filter material pellets reach the strength and hardness requirements required for industrial applications.

In the existing bioceramic filter material production process, the rotary kiln is used as its main calcining equipment. The combustion system supplies heat into the rotary kiln in the form of high-temperature flue gas, and heats and calcines the reverse-flowing ceramic filter material. The ceramic filter material that has completed the calcination process is discharged from the launder at the kiln head at high temperature and enters the cooling cylinder for cooling. In order to enhance the cooling effect, cooling water is usually sprayed on the outer wall of the cooling cylinder to take away the heat stored in the high-temperature calcined ceramic filter material and achieve the purpose of reducing the temperature of the ceramic filter material. After spraying, the heated cooling water flows into the storage tank for recycling. However, the above-mentioned bioceramic filter material production process has the following disadvantages: (1), the waste heat resources carried by the high-temperature calcined pellets (ie ceramic filter material) are completely wasted, which is contrary to the circular economy principle of energy saving and emission reduction ; (2), in the cooling water spraying process, a large amount of cooling water becomes steam and loses, and the cooling water consumption is large, which is not conducive to the saving of water resources; and a large amount of power is consumed in the cooling water circulation spraying process; (3) 1. Long-term spraying of cooling water, severe oxidation and corrosion of cooling equipment, increased equipment repair and maintenance costs; (4), long-term spray cooling process produces a large amount of hot steam in the surrounding environment, deteriorating the operating environment.

For the heat lost in the production process of recycling pellets, relevant technical solutions have been disclosed in the prior art, such as patent publication number: CN 203824299 U, publication date: September 10, 2014, and the name of the invention is: Rotary Kiln Waste Heat Utilization structure and rotary kiln production system. This application discloses a rotary kiln waste heat utilization structure and a rotary kiln production system. The rotary kiln waste heat utilization structure includes a rotary kiln discharge pipeline and a combustion-supporting gas pipeline connecting the rotary kiln and the cooling kiln. As well as the gas pipeline connected with the rotary kiln, the combustion-supporting gas pipeline extends through the discharge pipeline of the rotary kiln and is connected to the rotary kiln, so as to be able to supply the combustion-supporting gas into the rotary kiln. The combustion-supporting gas is heated by the waste heat of the rotary kiln in the discharge pipeline of the rotary kiln, and then passed into the rotary kiln, thereby reducing the consumption of gas. At the same time, the combustion-supporting gas exchanges heat with the waste heat of the rotary kiln in the discharge pipeline of the rotary kiln, thereby reducing the cooling load of the subsequent cooling process. But this application also has the following disadvantages: (1), the residence time of the pellets in the discharge pipeline of the rotary kiln is relatively short, the heat carried on the pellets is difficult to fully utilize, and the utilization efficiency of the waste heat of the rotary kiln is low; ( 2) The cooling kiln still needs to cool the pellets with a certain temperature in it by spraying, which wastes a lot of waste heat resources, consumes a lot of cooling water, increases the cost of equipment repair and maintenance, and deteriorates the operating environment .

To sum up, how to overcome the disadvantages of low waste heat utilization efficiency, large amount of cooling water waste, easy corrosion of cooling equipment and harsh operating environment in the prior art is a technical problem that needs to be solved urgently.

Contents of the invention

1. The technical problem to be solved by the invention

The purpose of the present invention is to overcome the disadvantages of the prior art, such as low utilization efficiency of waste heat in the pellet calcining rotary kiln, waste of a large amount of cooling water, easy corrosion of cooling equipment and poor operating environment, and to provide a circular partition wall for the waste heat of the pellet calcining rotary kiln. The recovery system and method achieve the goals of improving the waste heat utilization efficiency of the rotary kiln, reducing cooling water consumption, reducing the probability of cooling equipment being corroded, and improving the operating environment.

2. Technical solution

In order to achieve the above object, the technical scheme provided by the invention is:

The waste heat annular partition wall recovery system of pellet calcined rotary kiln products of the present invention includes a burner, a combustion chamber, a rotary kiln, a discharge port, a cooling cylinder bearing seat, a cooling cylinder driving wheel and a cooling cylinder, and the burner is located in the combustion chamber Generate combustion flames and calcinate the pellets in the rotary kiln; the calcined pellets flow out from the discharge port to the feed port of the cooling cylinder; there are two cooling cylinder bearing seats, and the cooling cylinder is installed obliquely at two different heights On the bearing seat of the cooling cylinder, the height of the inlet of the cooling cylinder is higher than the height of the outlet of the cooling cylinder; the driving wheel of the cooling cylinder drives the cooling cylinder to rotate;

It also includes an annular partition wall heat exchange mechanism and an air supply pipe heat exchange mechanism; the cooling cylinder is divided into three sections along the direction from the cooling cylinder inlet to the cooling cylinder outlet, which are called high temperature section, medium temperature section and low temperature section respectively. ;

The annular partition wall heat exchange mechanism includes a fan, an air induction main pipe, a high temperature section air induction pipe, a high temperature section cover and a medium temperature section cover; the high temperature section cover and the medium temperature section cover are both cylinders with openings at both ends; The inner diameters of the high-temperature section cover and the medium-temperature section cover are both larger than the outer diameter of the cooling cylinder; the high-temperature section cover is set on the high-temperature section, and the medium-temperature section cover is set on the medium-temperature section; the inlet of the high-temperature section air duct The end is connected with the middle position on the side of the cover body in the high temperature section, and the outlet end of the air induction pipe in the high temperature section is connected with the side of the main air duct; The outlet end of the main pipe is connected with the suction port of the fan;

The heat exchange mechanism of the air supply pipe includes an air supply pipe, and the air supply pipe includes a heat preservation section of the air supply pipe and a heating section of the air supply pipe; the inlet end of the heat preservation section of the air supply pipe is connected with the air outlet of the fan, The outlet end of the heat preservation section is connected with the inlet end of the heating section of the air supply pipe, and the outer surface of the heat preservation section of the air supply pipe is wrapped with insulation materials; the heating section of the air supply pipe is located inside the cooling cylinder, and the outlet end of the heating section of the air supply pipe Stretch out the feeding port of the cooling cylinder, and the outlet end of the heating section of the air supply pipe is connected with the air inlet of the burner through the pipe.

As a further improvement of the pellet calcined rotary kiln product waste heat annular partition wall recovery system of the present invention,

It also includes a feeding mechanism located between the discharge port and the cooling cylinder feeding port. The feeding mechanism includes a launder, a fixed jaw, a movable jaw and a cam. The fixed jaw is L-shaped, and the fixed jaw is fixed on the upper part of the launder The upper end of the movable jaw is fixed on the upper side of the launder through a rotating shaft and the inner surface of the movable jaw is opposite to the fixed jaw; the cam is located below the movable jaw and the cam is in contact with the outer surface of the movable jaw; A rotating shaft is fixed on the rotating center of the machine, and the rotating shaft is connected with the output shaft of the frequency conversion motor, and the movable jaw swings through the rotation of the cam.

As a further improvement of the pellet calcined rotary kiln product waste heat annular partition wall type recovery system of the present invention, the middle temperature section cover body includes the middle temperature section upper cover body and the middle temperature section lower cover body, the middle temperature section upper cover body and the middle temperature section lower cover body The body is semi-cylindrical, the side end surface of the upper cover body of the middle temperature section and the side end surface of the lower cover body of the middle temperature section are fixedly connected with connecting plates, the connecting plate on the side end surface of the upper cover body of the middle temperature section The connecting plates on the side end faces cooperate with each other and are fixed together by connecting bolts;

The structure of the high temperature section cover is the same as that of the middle temperature section cover.

As a further improvement of the pellet calcined rotary kiln product waste heat annular partition wall recovery system of the present invention,

The middle position on the cover body of the middle temperature section is called the cover body expansion section, and the inner diameter of the cover body expansion section is larger than the inner diameters at both sides of the middle position on the cover body of the middle temperature section;

The middle position on the cover body of the high temperature section is called the enlarged section of the cover body of the high temperature section, and the inner diameter of the enlarged section of the cover body of the high temperature section is larger than the inner diameters of the two sides of the middle position on the cover body of the high temperature section.

As a further improvement of the pellet calcined rotary kiln product waste heat annular partition wall recovery system of the present invention,

The inner surface of the heating section of the air supply pipe is welded with ribs at equal intervals along the circumferential direction; the inner surface of the cooling cylinder is welded with dispersing rods at equal intervals along the circumferential direction; the dispersing rod is L-shaped, and the dispersing rod One end is welded to the inner surface of the cooling cylinder.

As a further improvement of the pellet calcined rotary kiln product waste heat annular partition wall recovery system of the present invention,

The launder, fixed jaw, movable jaw and cam are all made of heat-resistant steel;

During the swinging process of the movable jaw, the distance between the movable jaw and the fixed jaw is controlled at 20-50mm;

The outer surface of the insulation section of the air supply pipe is wrapped with insulation cotton.

As a further improvement of the pellet calcined rotary kiln product waste heat annular partition wall recovery system of the present invention,

The central axis of the high-temperature section cover coincides with the central axis of the high-temperature section, and the central axis of the medium-temperature section cover coincides with the central axis of the medium-temperature section; the length of the high-temperature section cover is 1500-2000 mm, and the length of the medium-temperature section cover is 3000-4500mm; the inner diameter of both sides of the enlarged section of the high-temperature section cover is larger than the outer diameter of the cooling cylinder by 20-100mm, and the inner diameter of both sides of the expanded section of the upper cover of the middle-temperature section is larger than the outer diameter of the cooling cylinder 20-100mm; the inner diameter of the expanded section of the cover is 20-200mm larger than the inner diameter of the enlarged section of the upper cover of the middle-temperature section, and the inner diameter of the expanded section of the cover of the high-temperature section is larger than that of the expanded section of the upper high-temperature section of the cover by two times. The inner diameter of the side is 20-200mm; the length of the expanded section of the cover body is 200-1500mm, and the length of the expanded section of the cover body in the high-temperature section is 200-1500mm; The inner diameter of the heat preservation section of the pipe and the heating section of the air supply pipe is 150-500mm, and the inner diameter of the outlet end of the heating section of the air supply pipe is reduced to 50-100mm.

As a further improvement of the pellet calcined rotary kiln product waste heat annular partition wall recovery system of the present invention,

The number of the ribs is 10-20, and the height of each rib is 30-80mm.

As a further improvement of the waste heat annular partition wall recovery system for pellet calcined rotary kiln products of the present invention, a spraying device is provided above the low temperature section.

The method for recovering the residual heat of the rotary kiln product waste heat of the pellet calcining rotary kiln according to the present invention comprises the following steps,

Step A: After being calcined in the rotary kiln, the pellets with a temperature of 800-900°C flow out from the discharge port and enter the feed port of the cooling cylinder through the feeding mechanism; wherein, the pellets are crushed in the feeding mechanism, and the movable jaw The swing frequency is 2-5 times per second, and the distance between the movable jaw and the fixed jaw is controlled at 20-50mm during the swinging process of the movable jaw;

Step B: The driving wheel of the cooling cylinder drives the cooling cylinder to rotate, so that the pellets at the inlet of the cooling cylinder are transported to the outlet of the cooling cylinder; the pellets are heated in the cooling cylinder and the heating section of the air supply pipe, and on the cooling cylinder The average wall temperature of the high-temperature section is 550°C, the average wall temperature of the medium-temperature section is 400°C, and the average wall temperature of the low-temperature section is 150°C; among them, the pellets at the bottom of the cooling cylinder are rotated by the cooling cylinder. The dispersing rod at the bottom gathers together, and the gathered pellets fall freely when they rotate to the top inside the cooling cylinder. After the pellets fall freely, they are gathered by the dispersing rod again and then fall freely, reciprocating in this way until the pellets are discharged from the outlet of the cooling cylinder. ;

Step C: Turn on the fan, and the fan draws the air in the annular gap between the high temperature section cover and the high temperature section through the high temperature section air duct, and the air in the annular gap between the high temperature section cover and the high temperature section is mixed with the high temperature during the extraction process. The wall surface of the middle temperature section conducts convective heat exchange, and the air temperature rises; the fan draws the air in the ring gap between the middle temperature section cover and the middle temperature section through the main air duct, and the air in the ring gap between the middle temperature section cover and the middle temperature section is being extracted. During the process, it conducts convective heat exchange with the wall surface of the medium temperature section, and the air temperature rises;

Step D: The air drawn by the fan through the induced air duct of the high temperature section and the main induced air duct is mixed and then sent to the heating section of the air supply pipe for further heating, and the temperature of the air rises again; wherein, the inner surface of the heating section of the air supply pipe is along the circumferential direction, etc. Spacing welded ribbed plates;

Step E: The heated air in the heating section of the air supply pipe is sent to the air inlet of the burner through the pipe to supply preheated air for the flame combustion in the combustion chamber.

3. Beneficial effect

Compared with the prior art, the technical solution provided by the invention has the following remarkable effects:

(1) In the existing process of producing pellets by calcining in a rotary kiln, the waste heat carried by the pellets after calcination accounts for 50% of the total heat input, so the recovery of waste heat from rotary kiln products is the key to improving the utilization efficiency of waste heat in rotary kilns Therefore, the waste heat annular partition wall recovery system of pellet calcined rotary kiln products of the present invention is designed based on the full recovery of waste heat resources carried by pellets after high-temperature calcination, and at the same time considering the specific problems encountered in the process of pellet waste heat recovery of. In the present invention, firstly, the air is divided into two paths, one path of air conducts convective heat exchange on the wall surface of the high temperature section, and the other path of air conducts convective heat exchange on the wall surface of the medium temperature section, the temperature of the two paths of air rises for the first time after absorbing heat, and Mixing in the fan; wherein, the air is divided into two channels to conduct convective heat exchange on the wall surface of the high temperature section and the wall surface of the medium temperature section, which is beneficial to improve the efficiency and reliability of air heat exchange. The hot air mixed in the fan is sent to the heating section of the air supply pipe, and is reheated in the heating section of the air supply pipe. The hot air after the second heating is sent to the air inlet of the burner to supply the flame combustion in the combustion chamber Preheating the air improves the combustion efficiency and combustion temperature of the fuel (the combustion temperature is increased by more than 100°C); in the present invention, the air is heated twice through the annular partition wall heat exchange mechanism and the air supply pipe heat exchange mechanism, which increases the number of rotary kiln products. The amount of waste heat recovery greatly improves the utilization efficiency of rotary kiln waste heat.

(2), the waste heat annular partition wall recovery system and method of the pellet calcined rotary kiln product of the present invention, through the process that the air is heated twice, fully absorb the waste heat carried by the pellet itself after the calcination, and the pellet from the cooling cylinder After discharge from the discharge port, the temperature drops greatly, and there is no need to use or only a small amount of cooling water to spray and cool the cooling cylinder, which reduces the consumption of cooling water, is conducive to the saving of water resources, and reduces the chance of corrosion of cooling equipment. It avoids the occurrence of a large amount of hot steam that deteriorates the operating environment, and improves the operating environment.

(3), the waste heat annular partition wall recovery system of the pellet calcining rotary kiln product of the present invention adds a set of simple jaw crushing device in the feeding mechanism, which can reduce the existence of agglomerates in the pellets and avoid agglomerated pellets The impact damage to the heating section of the air supply pipe and the wear and tear on the production equipment; and the jaw crushing device breaks all the pellets into small pellets, which ensures the smooth flow of the pellets in the feeding mechanism and increases the quality of the product. High efficiency, which is conducive to the uniform and sufficient heat dissipation of pellets in the heating section of the air supply pipe, and improves the efficiency of waste heat recovery of pellets.

(4), in the present invention, along with the rotation of the cooling cylinder, the pellets at the bottom of the cooling cylinder are gathered by the dispersing rod at the bottom of the cooling cylinder, and the gathered pellets fall freely when rotating to the top of the cooling cylinder, and the pellets are free After falling, it is gathered again by the dispersing rod and then falls freely, reciprocating in this way until the pellets are discharged from the outlet of the cooling cylinder; the process of the pellets being picked up to the highest point by the dispersing rod and then falling is conducive to the uniform and sufficient heat dissipation of the pellets , while prolonging the residence time of pellets in the cooling cylinder, improving the efficiency of waste heat recovery of pellets.

(5), in the waste heat annular partition wall recovery system of the granular material calcining rotary kiln product of the present invention, the inner surface of the heating section of the air supply pipe is welded with ribs at equal intervals along the circumference, and the setting of the ribs is used to increase air and heat on the one hand. The heat exchange area of the heating section of the air supply pipe improves the efficiency of pellet waste heat recovery; on the other hand, it can reduce the bending deformation of the heating section of the air supply pipe and improve the strength of the heating section of the air supply pipe.

Description of drawings

Fig. 1 is the structure schematic diagram of the waste heat annular partition wall type recovery system of pellet calcined rotary kiln product of the present invention;

Fig. 2 is a schematic cross-sectional structure diagram along the radial direction of the middle temperature section cover in the present invention;

Fig. 3 is a top view structure schematic diagram of the middle temperature section cover body in the present invention;

Fig. 4 is the structural representation of unloading mechanism in the present invention;

Fig. 5 is a schematic cross-sectional structure diagram along the radial direction of the heating section of the air supply pipe in the present invention.

Explanation of the labels in the schematic diagram: 1. Burner; 2. Combustion chamber; 3. Rotary kiln; 4. Fan; Air pipe heating section; 6021, rib plate; 7, spray device; 8, discharge port; 9, feeding mechanism; 901, launder; 902, fixed jaw; 903, movable jaw; 904, cam; Section cover; 11. Cooling tube bearing seat; 12. Connecting bolt; 13. Connecting plate; 14. Medium temperature section cover; 1401. Cover expansion section; 15. Cooling tube drive wheel; 16. Cooling tube; pole.

Detailed ways

In order to further understand the content of the present invention, the present invention will be described in detail in conjunction with the accompanying drawings and embodiments.

Example 1

As shown in Figure 1, the waste heat annular partition wall recovery system for pellet calcined rotary kiln products in this embodiment includes a burner 1, a combustion chamber 2, a rotary kiln 3, a discharge port 8, a cooling cylinder bearing seat 11, and a cooling cylinder drive wheel 15 and cooling cylinder 16. The burner 1 generates a combustion flame in the combustion chamber 2. The high-temperature flue gas generated by the combustion flame enters the rotary kiln 3 and calcines the pellets in the rotary kiln 3. The calcined pellets flow out from the discharge port 8 to the inlet of the cooling cylinder 16. feed port. There are two cooling cylinder bearing seats 11, and the cooling cylinder 16 is obliquely installed on two cooling cylinder bearing seats 11 of different heights. 16, the cooling cylinder bearing seat 11 at the discharge port, so that the height at the inlet of the cooling cylinder 16 is higher than the height at the discharge port of the cooling cylinder 16. The cooling cylinder driving wheel 15 and the cooling cylinder 16 are geared, the cooling cylinder driving wheel 15 drives the cooling cylinder 16 to rotate, and the pellets in the cooling cylinder 16 move to the discharge port of the cooling cylinder 16 along with the rotation of the cooling cylinder 16 .

The annular partition wall type recovery system for waste heat of pellet calcined rotary kiln products in this embodiment also includes an annular partition wall heat exchange mechanism, an air supply pipe heat exchange mechanism and a feeding mechanism 9 . The cooling cylinder 16 is divided into three sections along the direction from the inlet of the cooling cylinder 16 to the outlet of the cooling cylinder 16, which are respectively called high temperature section, medium temperature section and low temperature section. The annular partition wall heat exchange mechanism includes a fan 4 , an air induction main pipe 501 , an air induction pipe 502 in the high temperature section, a cover body 10 in the high temperature section and a cover body 14 in the middle temperature section. The fan 4 is a negative pressure fan, the air inlet of the fan 4 is used to suck the air from the outside, and the air outlet of the fan 4 is used to discharge the sucked air. Both the high temperature section cover body 10 and the middle temperature section cover body 14 are cylinders with openings at both ends. The inner diameters of the high-temperature section cover 10 and the middle-temperature section cover 14 are larger than the outer diameter of the cooling cylinder 16, the high-temperature section cover 10 is set on the high-temperature section, and the middle-temperature section cover 14 is set on the middle-temperature section. The inlet end of the high temperature section air duct 502 communicates with the middle position of the side surface of the high temperature section cover body 10 , and the outlet end of the high temperature section air duct 502 communicates with the side of the main air duct 501 . The inlet end of the main air duct 501 communicates with the middle position on the side of the cover body 14 in the middle temperature section, and the outlet end of the main air duct 501 communicates with the air suction port of the fan 4 . The middle temperature section cover body 14 comprises the middle temperature section upper cover body and the middle temperature section lower cover body. The connecting plates 13 on the side end faces of the middle temperature section and the lower cover body in the middle temperature section cooperate with each other and are fixed and sealed together by connecting bolts 12. The structure of the high temperature section cover body 10 is the same as that of the middle temperature section cover body 14 .

In this embodiment, if the middle temperature section cover body 14 is a straight cylinder, then when the air blower 4 sucks the air in the ring gap between the middle temperature section cover body 14 and the middle temperature section, the two airflows at both ends of the ring gap are in the process of drawing the air. The inlet ends of the main pipe 501 converge, and a short-circuit area will be formed at the ring seam facing the inlet end of the air main pipe 501. The air in this short-circuit area is almost in a static state, which greatly reduces the heat exchange effect between the air and the wall surface of the medium temperature section, and it is difficult to achieve air and medium temperature. Effective heat exchange on the wall surface of the section; if the inner diameter of the middle-temperature section cover body 14 connected to the inlet end of the main air duct 501 is enlarged, at this time, when the gas at both ends of the annular seam reaches the annular seam facing the inlet end of the main air duct 501, it will appear A certain degree of air flow disturbance makes air flow into the main air duct 501 along the wall surface of the medium temperature section, which greatly enhances the heat exchange effect between the air and the wall surface of the medium temperature section, and improves the efficiency of heat recovery. If the high-temperature section cover body 10 is straight cylindrical, then the same is true. Therefore, as shown in FIG. 3 , the middle position on the middle temperature section cover body 14 is called the cover body expansion section 1401 , and the inner diameter of the cover body expansion section 1401 is larger than the inner diameters at both sides of the middle position on the middle temperature section cover body 14 . The middle position on the high-temperature section cover body 10 is called the high-temperature section cover body expansion section, and the inner diameter of the high-temperature section cover body expansion section is greater than the internal diameters at both sides of the middle position on the high-temperature section cover body 10 (the high-temperature section cover body expansion section is shown in Fig. 1 omitted, not shown).

The air supply pipe heat exchange mechanism includes an air supply pipe, and the air supply pipe includes an air supply pipe insulation section 601 and an air supply pipe heating section 602 . The inlet end of the air supply pipe insulation section 601 is connected with the air outlet of the fan 4, the outlet end of the air supply pipe insulation section 601 is connected with the inlet end of the air supply pipe heating section 602, and the outer surface of the air supply pipe insulation section 601 is used The insulation material is wrapped, and the insulation material in this embodiment is insulation cotton, which is used to insulate the insulation section 601 of the air supply pipe to reduce heat loss. The heating section 602 of the air supply pipe is arranged inside the cooling cylinder 16, the outlet end of the heating section 602 of the air supply pipe protrudes from the feed port of the cooling cylinder 16, and the outlet end of the heating section 602 of the air supply pipe passes through the pipe and the air from the burner 1. The import is connected. As shown in Figure 5, the inner surface of the heating section 602 of the air supply pipe is welded with ribs 6021 at equal intervals along the circumference, and the number of ribs 6021 is 10 to 20 pieces. Specifically, the number of ribs 6021 in this embodiment is 10 pieces. The height of each rib plate 6021 is 30-80mm. Specifically, the height of each rib plate 6021 in this embodiment is 30mm. The rib plate 6021 is used to increase the heat exchange area on the one hand, and can reduce the heating section of the air supply pipe on the other hand. Bending deformation of 602; the manufacturing method of the heating section 602 of the air supply pipe is to first weld the corresponding rib plate 6021 on a rectangular plate, and then roll it into a pipe. As shown in Figure 2, the inner surface of the cooling cylinder 16 is welded with dispersing rods 1601 at equal intervals along the circumference, and the dispersing rods 1601 are L-shaped, and one end of the dispersing rods 1601 is welded on the inner surface of the cooling cylinder 16; The connection line of the opening direction of the other end is the same as the rotation direction of the cooling cylinder 16, so that the dispersing rod 1601 is designed to facilitate the picking up of the pellets in the cooling cylinder 16 during the rotation of the cooling cylinder 16.

As shown in Figure 4, the unloading mechanism 9 is located between the discharge port 8 and the feed inlet of the cooling cylinder 16. The unloading mechanism 9 includes a flow groove 901, a fixed jaw 902, a movable jaw 903 and a cam 904. The fixed jaw 902 is L-shaped, the fixed jaw 902 is fixed on the upper side of the launder 901, the upper end of the movable jaw 903 is fixed on the upper side of the launder 901 by a rotating shaft and the inner surface of the movable jaw 903 is opposite to the fixed jaw 902. The cam 904 is disposed below the movable jaw 903 and the cam 904 is in contact with the outer surface of the movable jaw 903 . A rotating shaft is fixed on the rotation center of the cam 904, and the rotating shaft is connected with the output shaft of the frequency conversion motor, and the movable jaw 903 swings through the rotation of the cam 904. The fixed jaw 902, the movable jaw 903 and the cam 904 together constitute a simple jaw crushing device. Launder 901, fixed jaw 902, movable jaw 903 and cam 904 are all made of heat-resistant steel with a maximum working temperature greater than 900°C. The heat-resistant steel in this embodiment is oxidation-resistant steel 0Cr25Ni20 that can withstand repeated heating below 1000°C. The swing frequency of the movable jaw 903 is 2 to 5 times per second. In this embodiment, the swing frequency of the movable jaw 903 is 2 times per second, and the swing frequency is controlled by a variable frequency motor connected to the cam 904; Its installation position is such that the distance between the movable jaw 903 and the fixed jaw 902 is controlled at 20-50 mm during the swing process of the movable jaw 903. Specifically, in this embodiment, the distance between the movable jaw 903 and the fixed jaw 902 is controlled at 20 mm. It can ensure the smooth flow of small particles while breaking the agglomerated particles.

The central axis of the high-temperature section cover 10 coincides with the central axis of the high-temperature section, and the central axis of the medium-temperature section cover 14 coincides with the central axis of the medium-temperature section. The length of the high-temperature section cover 10 is 1500-2000mm, which is 2000mm in this embodiment; the length of the medium-temperature section cover 14 is 3000-4500mm, which is 4400mm in this embodiment; The inner diameters at both sides are 20-100 mm larger than the outer diameter of the cooling cylinder 16, 20 mm in this embodiment; In this embodiment, 20 mm is taken; the inner diameter of the enlarged section 1401 of the cover body is greater than the inner diameter of 20-200 mm at both sides of the enlarged section 1401 of the cover body 14 of the middle temperature section, and 20 mm is taken in this embodiment; the inner diameter of the enlarged section of the cover body of the high temperature section It is 20-200 mm larger than the inner diameter of both sides of the high-temperature section cover body expansion section on the high-temperature section cover body 10, which is 20 mm in this embodiment; the length of the cover body expansion section 1401 is 200-1500 mm, and 200 mm is taken in this embodiment; The length of the enlarged section of the cover body is 200-1500 mm, which is 200 mm in this embodiment; the inner diameter of the main air-introduction pipe 501 and the air-induction pipe 502 of the high-temperature section is 200-500 mm, and the inner diameter of the main air-induction pipe 501 in this implementation is 300 mm, and the inner diameter of the air-induction main pipe 501 in the high-temperature section is 300 mm. The inner diameter of the air induction pipe 502 is 200mm; the inner diameter of the air supply pipe insulation section 601 and the air supply pipe heating section 602 is 150-500mm, and the inner diameters of the air supply pipe insulation section 601 and the air supply pipe heating section 602 in this embodiment are both 300mm; considering the layout of the feeding mechanism 9, the inner diameter of the outlet end of the air supply pipe heating section 602 is reduced to 50-100mm, and the inner diameter of the air supply pipe heating section 602 outlet end is reduced to 50mm in this embodiment.

The method for recovering the waste heat of the rotary kiln products of pellet calcining in the present embodiment is an annular partition wall recovery method, which recovers the heat of the calcined products by preheating the air required for combustion, and mainly includes the following steps,

Step A: After being calcined in the rotary kiln 3 , the high-temperature pellets at a temperature of 800-900° C. flow out from the discharge port 8 and enter the feed port of the cooling cylinder 16 through the feeding mechanism 9 . Among them, in the feeding mechanism 9, the agglomerated pellets are crushed by the jaw crushing device, the swing frequency of the movable jaw 903 is 2 times per second, and the distance between the movable jaw 903 and the fixed jaw 902 during the swing of the movable jaw 903 is Controlled at 20mm;

Step B: The driving wheel 15 of the cooling cylinder drives the cooling cylinder 16 to rotate, so that the pellets at the inlet of the cooling cylinder 16 are transported to the outlet of the cooling cylinder 16 . The pellets heat the wall surface of the cooling cylinder 16 and the wall surface of the heating section 602 of the air supply pipe through radiation and heat conduction in the cooling cylinder 16 . The average wall temperature of the high temperature section on the cooling cylinder 16 is 550°C, the average wall temperature of the middle temperature section is 400°C, and the average wall temperature of the low temperature section is 150°C. Wherein, as shown in Figure 2, the pellets at the bottom of the cooling cylinder 16 are gathered by the dispersing rod 1601 at the bottom of the cooling cylinder 16 along with the rotation of the cooling cylinder 16, and the gathered pellets are free when they rotate to the top of the cooling cylinder 16 Falling, after the pellets fall freely, they are gathered again by the dispersing rod 1601 and then fall freely, reciprocating in this way until the pellets are discharged from the outlet of the cooling cylinder 16. The process that the pellets are picked up to the highest point by the dispersing rod 1601 and then falls is conducive to the uniform and sufficient heat dissipation of the pellets, and at the same time prolongs the residence time of the pellets in the cooling cylinder 16, improving the efficiency of waste heat recovery of the pellets; however, The pellets will impact the heating section 602 of the air supply pipe during the falling process, and the impact of the pellets with small particles will have less impact, but if there are large agglomerates in the pellets, the impact of the agglomeration on the heating section 602 of the air supply pipe will be large. greatly reduce its service life. In this embodiment, in order to solve this problem, a set of simple jaw crushing device is designed in the unloading mechanism 9, and its purpose is in order to reduce the existence of agglomeration in the granular material, avoid the agglomerated granular material to the heating section of the air supply pipe. 602 impact damage; and the jaw crushing device breaks all the pellets into small pellets, which is conducive to the uniform and sufficient heat dissipation of the pellets in the heating section 602 of the air supply pipe, and improves the efficiency of waste heat recovery of pellets.

Step C: Turn on the fan 4, and the fan 4 draws the air in the annular gap between the high-temperature section cover 10 and the high-temperature section through the high-temperature section air duct 502, and the air in the surrounding environment is continuously replenished into the gap between the high-temperature section cover 10 and the high-temperature section The air in the annular gap between the high-temperature section cover body 10 and the high-temperature section performs convective heat exchange with the wall surface of the high-temperature section during the extraction process, taking away part of the heat, and the air temperature rises at this time. The fan 4 extracts the air in the annular gap between the middle temperature section cover body 14 and the middle temperature section through the air main pipe 501, and the air in the surrounding environment is continuously replenished into the annular gap between the middle temperature section cover body 14 and the middle temperature section, and the middle temperature section The air in the annular gap between the cover body 14 and the middle temperature section performs convective heat exchange with the wall surface of the middle temperature section during the extraction process, taking away part of the heat, and the air temperature rises at this time.

In the present embodiment, the inner diameter of the cooling cylinder 16 is 800 mm, the inner diameter of the high temperature section cover body 10 is 820 mm, that is, the thickness of the annular seam between the high temperature section cover body 10 and the high temperature section is 10 mm, and the length of the high temperature section cover body 10 is 2000mm; the inner diameter of the cover body 14 in the middle temperature section is 820mm, and the length is 4400mm. When the air flow required for flame combustion in the burner 1 is 2500m ³ /h, by adjusting the power of the fan 4 and the flow valve (flow valves are provided on the main air induction pipe 501 and the air induction pipe 502 in the high temperature section), the flow rate from the high temperature is controlled. The amount of air sucked from the ring gap between the section cover 10 and the high temperature section is 1000m ³ /h, and the air sucked from the ring gap between the middle temperature section cover 14 and the middle temperature section is 1500m ³ /h.

The following is the calculation of the heat exchange that air takes place in the high-temperature section cover 10 and the middle-temperature section cover 14:

Heat transfer: Q=k·s·Δt

In the formula: k--comprehensive heat transfer coefficient, take k=20W/m ² K;

S - heat transfer area, m ² ;

Δt--temperature difference, K.

Air temperature rise: ${\mathrm{\Δt}}^{\′}=\frac{Q}{C_{p}m}=\frac{Q}{C_p\mathrm{\ρ}V}$

In the formula: Q--heat exchange rate, kW;

C _p -- air specific volume, take C _p = 1.005kJ/kgK;

ρ--air density, take ρ=1.1kg/m ³ ;

V--volume flow, m ³ /s

①. Inside the cover body 10 of the high-temperature section: take the air inlet temperature as 30°C, and set the air outlet temperature as 175°C;

Q＝20×π×0.8×1×(550+550-30-175)/2

=20×2.512×447.5

=22.48KW

Therefore, the temperature of the air inside the cover 10 in the high temperature section rises by 146°C, that is, the air outlet temperature is 176°C, which is basically consistent with the assumption and meets the requirements.

②. In the cover body 14 of the middle temperature section: take the air inlet temperature as 30°C, and set the air outlet temperature as 175°C;

Q＝20×π×0.8×2.2×(400+400-30-175)/2

=20×5.53×297.5

=32.9KW

Therefore, the temperature of the air in the cover body 14 in the middle temperature section rises by 143°C, that is, the air outlet temperature is 173°C, which is basically consistent with the assumption and meets the requirements.

After the above calculation, the temperature of the air rises to 175° C. after the first heat exchange in the high-temperature section cover 10 and the middle-temperature section cover 14 .

Step D: The hot air extracted by the fan 4 through the high-temperature section air-induction pipe 502 and the air-induction main pipe 501 is mixed and sent to the air supply pipe heating section 602, and the hot air is mixed with the air supply pipe heating section 602 in the air supply pipe heating section 602 The inner wall of the air is subjected to convection and radiation heat exchange, the air is reheated, and the air temperature rises again. As shown in Figure 5, the inner surface of the heating section 602 of the air supply pipe is welded with ribs 6021 at equal intervals along the circumference. The strength of the heating section 602 of the air duct. In this embodiment, the arrangement of the ribs 6021 doubles the heat exchange area between the air and the heating section 602 of the air supply duct. The flow direction of the air in the heating section 602 of the air supply pipe is opposite to the conveying direction of the pellets in the cooling cylinder 16 , which is beneficial to improve the heat exchange efficiency of the air in the heating section 602 of the air supply pipe.

In this embodiment, the inner diameter of the heating section 602 of the air supply pipe is 300mm, and the length is 10000mm; the temperature of the wall surface at the inlet end of the heating section 602 of the air supply pipe is 200°C, and the temperature of the wall surface at the outlet end of the heating section 602 of the air supply pipe is 800°C. Assume that the outlet temperature of the air after being reheated in the heating section 602 of the air supply pipe is 300°C.

Q＝20×π×0.3×10×2×(200+800-175-300)/2

=20×18.84×262.5

=98.91KW

Therefore, the air temperature in the heating section 602 of the air supply pipe rises by 128°C, that is, the air outlet temperature is 303°C, which is basically consistent with the assumption and meets the requirements.

Step E: According to the above calculation, the air reheated to 300°C in the heating section 602 of the air supply pipe is sent into the air inlet of the burner 1 through the pipe to supply preheated air for the flame combustion in the combustion chamber 2, which can improve Fuel combustion efficiency and combustion temperature.

In the pellet calcining rotary kiln waste heat recovery system of this embodiment, a set of simple jaw crushing device is added to the feeding mechanism 9, which can reduce the presence of agglomerates in the pellets and prevent the agglomerated pellets from being fed to each other. The impact damage of the heating section 602 of the air duct and the wear and tear on the production equipment; and the jaw crushing device breaks all the pellets into small pellets, which ensures the smooth flow of the pellets in the feeding mechanism 9 and increases the quality of the product. The efficiency is beneficial to the uniform and sufficient heat dissipation of the pellets in the heating section 602 of the air supply pipe, which improves the efficiency of waste heat recovery of the pellets.

In the waste heat annular partition wall recovery system for pellet calcined rotary kiln products in this embodiment, the inner surface of the heating section 602 of the air supply pipe is welded with ribs 6021 at equal intervals along the circumference. The setting of the ribs 6021 is used to increase air and The heat exchange area of the heating section 602 of the air supply pipe improves the efficiency of waste heat recovery of pellets;

In the existing process of producing pellets by calcining in a rotary kiln, the waste heat carried by the pellets after calcination accounts for 50% of the total heat input. Therefore, the recovery of waste heat from rotary kiln products is the key to improving the utilization efficiency of waste heat in rotary kilns. This implementation The example of pellet calcined rotary kiln product waste heat annular partition wall recovery system is designed based on the full recovery of waste heat resources carried by pellets after high-temperature calcination, while considering the specific problems encountered in the process of pellet waste heat recovery. In this embodiment, firstly, the air is divided into two paths, one path of air conducts convective heat exchange on the wall surface of the high temperature section, and the other path of air conducts convective heat exchange on the wall surface of the medium temperature section, and the temperature of the two paths of air rises for the first time after absorbing heat. And mix in fan 4; Wherein, air divides into two roads and carries out convective heat exchange on the wall surface of high temperature section and the wall surface of middle temperature section respectively, helps to improve the efficiency of air heat exchange (because the wall surface temperature of high temperature section and the wall surface temperature of middle temperature section The difference is that the heat exchange effect of the air being divided into two channels for convective heat exchange is better than that of one channel of air directly for convective heat exchange, the heat exchange effect is better, and the heat exchange efficiency is higher) and reliability. The hot air mixed in the blower 4 is sent to the heating section 602 of the air supply pipe, and is reheated in the heating section 602 of the air supply pipe. The flame combustion in 2 supplies preheated air, which improves the combustion efficiency and combustion temperature of the fuel (combustion temperature is increased by more than 100°C); Air, which increases the waste heat recovery of rotary kiln products, greatly improves the efficiency of rotary kiln waste heat utilization.

In this embodiment, the pellets at the bottom of the cooling cylinder 16 are gathered by the dispersing rod 1601 at the bottom of the cooling cylinder 16 as the cooling cylinder 16 rotates, and the gathered pellets fall freely when they rotate to the top of the cooling cylinder 16. After the material falls freely, it is gathered again by the dispersing rod 1601 and then falls freely, reciprocating in this way until the pellets are discharged from the outlet of the cooling cylinder 16. The process of the pellets being picked up to the highest point by the dispersing rod 1601 and then falling is conducive to the uniform and sufficient heat dissipation of the pellets, and at the same time prolongs the residence time of the pellets in the cooling cylinder 16, improving the efficiency of waste heat recovery of the pellets.

The pellet calcined rotary kiln waste heat recycling system and method in this embodiment, through the process of the air being heated twice, fully absorb the waste heat carried by the pellet itself after calcining, and the pellets are discharged from the cooling cylinder 16 After the outlet is discharged, the temperature drops greatly, no need to use or only a small amount of cooling water to spray and cool the cooling cylinder 16, which reduces the consumption of cooling water, is conducive to the saving of water resources, reduces the chance of cooling equipment being corroded, and avoids The occurrence of a large amount of hot steam that deteriorates the operating environment improves the operating environment.

In the system and method for recovering the waste heat of the pellet calcined rotary kiln products in the present embodiment, when the fan 4 sucks the surrounding air, the flow of the air can affect the cooling cylinder bearing seat 11 and the cooling cylinder driving wheel 15 installed on the cooling cylinder 16. A certain degree of cooling is carried out, thereby reducing the consumption of lubricating oil on the cooling cylinder bearing seat 11 and the consumption of gear lubricating oil on the cooling cylinder driving wheel 15, thereby increasing the service life of the cooling cylinder bearing seat 11 and the cooling cylinder driving wheel 15; in addition , the fan 4 sucks the surrounding air, which can reduce the temperature of the surrounding environment and improve the operating environment.

The waste heat annular partition wall recovery system of pellet calcined rotary kiln products in this embodiment has only made few changes on the basis of the original equipment, the transformation cost is low, and the operation and maintenance are convenient; by absorbing the waste heat of the calcined pellets itself The production of preheated air can reduce the amount of fuel used, and can save hundreds of thousands to millions of dollars for a production line every year.

Example 2

The pellet calcined rotary kiln product waste heat annular partition wall recovery system in this embodiment is basically the same as that in Embodiment 1, the difference is that in order to ensure that the pellets are fully cooled below the specified temperature, a spray is provided above the low temperature section Device 7, the spraying device 7 is a cooling water spraying device, and the spraying device 7 includes a row of cooling water pipes with uniform round holes on the sides, the cooling water flows down from the round holes on the side of the cooling water pipes, and is sprayed on the surface of the low temperature section , to lower the temperature of the low-temperature section, so that the pellets are further cooled.

Example 3

The waste heat annular partition wall recovery system for pellet calcined rotary kiln products in this embodiment is basically the same as that in Embodiment 1, the difference is that the inner surface of the heating section 602 of the air supply pipe is welded with ribs 6021 at equal intervals along the circumference, Specifically, the number of ribs 6021 in this embodiment is 15, and the height of each rib 6021 is 55 mm; the swing frequency of the movable jaw 903 in this embodiment is 3 times/second, and the movable jaw 903 and the fixed jaw 903 are in the swing process. The distance between the jaws 902 is controlled at 35mm; the length of the high-temperature section cover 10 is 1500mm, and the length of the middle-temperature section cover 14 is 3000mm; The outer diameter of 16 is 60 mm, and the inner diameter at both sides of the upper cover body expansion section 1401 of the middle temperature section cover body 14 is larger than the outer diameter of the cooling cylinder 16 by 60 mm; The inner diameter at both sides is 110mm; the inner diameter of the enlarged section of the high temperature section cover is larger than the inner diameter of 110mm at both sides of the expanded section of the high temperature section cover on the high temperature section cover 10; the length of the expanded section 1401 of the cover is 850mm; the enlarged section of the high temperature section cover The length of section is 850mm; In this implementation, the inner diameter of air induction main pipe 501 is 400mm, and the inner diameter of high temperature section air induction pipe 502 is 300mm; The inner diameter of air supply pipe insulation section 601 and air supply pipe heating section 602 is 150mm; In the example, the inner diameter of the outlet end of the heating section 602 of the air supply pipe is reduced to 75mm.

Example 4

The waste heat annular partition wall recovery system for pellet calcined rotary kiln products in this embodiment is basically the same as that in Embodiment 1, the difference is that the inner surface of the heating section 602 of the air supply pipe is welded with ribs 6021 at equal intervals along the circumference, Specifically, the number of ribs 6021 in this embodiment is 20, and the height of each rib 6021 is 80 mm; the swing frequency of the movable jaw 903 in this embodiment is 5 times/second, and the movable jaw 903 and the fixed jaw 903 are in the swing process. The distance between the jaws 902 is controlled at 50mm; the length of the high temperature section cover 10 is 1750mm, and the length of the middle temperature section cover 14 is 3800mm; the inner diameter of the two sides of the high temperature section cover expansion section on the high temperature section cover 10 is larger than the cooling cylinder The outer diameter of 16 is 100 mm, and the inner diameter at both sides of the upper cover body expansion section 1401 of the middle temperature section cover body 14 is greater than the outer diameter of 100 mm of the cooling cylinder 16; The inner diameter at both sides is 200mm; the inner diameter of the enlarged section of the high temperature section cover is larger than the inner diameter of 200mm at both sides of the expanded section of the high temperature section cover on the high temperature section cover 10; the length of the expanded section 1401 of the cover is 1500mm; the enlarged section of the high temperature section cover The length of section is 1500mm; In this implementation, the internal diameter of air induction main pipe 501 is 500mm, and the internal diameter of high temperature section air induction pipe 502 is 400mm; The internal diameter of air supply pipe insulation section 601 and air supply pipe heating section 602 is 500mm; In the example, the inner diameter of the outlet end of the heating section 602 of the air supply pipe is reduced to 100 mm.

The above schematically describes the present invention and its implementation, which is not restrictive, and what is shown in the drawings is only one of the implementations of the present invention, and the actual structure is not limited thereto. Therefore, if a person of ordinary skill in the art is inspired by it, without departing from the inventive concept of the present invention, without creatively designing a structural mode and embodiment similar to the technical solution, it shall all belong to the protection scope of the present invention .

Claims (10)

1. An annular partition wall recovery system for the waste heat of rotary kiln products for pellet calcining, including burner (1), combustion chamber (2), rotary kiln (3), discharge port (8), cooling cylinder bearing seat (11) , cooling cylinder driving wheel (15) and cooling cylinder (16), the burner (1) generates a combustion flame in the combustion chamber (2), and calcines the pellets in the rotary kiln (3); the calcined pellets are The material outlet (8) flows out to the feed inlet of the cooling cylinder (16); there are two cooling cylinder bearing seats (11), and the cooling cylinder (16) is obliquely installed on two cooling cylinder bearing seats of different heights ( 11), so that the height of the inlet of the cooling cylinder (16) is higher than the height of the outlet of the cooling cylinder (16); the driving wheel of the cooling cylinder (15) drives the rotation of the cooling cylinder (16); it is characterized in that: It also includes an annular partition wall heat exchange mechanism and an air supply pipe heat exchange mechanism; the cooling cylinder (16) is divided into three sections in sequence along the direction from the cooling cylinder (16) inlet to the cooling cylinder (16) outlet, respectively called High temperature section, medium temperature section and low temperature section; The annular partition wall heat exchange mechanism includes a fan (4), an air induction main pipe (501), a high temperature section air induction pipe (502), a high temperature section cover (10) and a medium temperature section cover (14); the high temperature section cover Both the body (10) and the middle temperature section cover (14) are cylinders with openings at both ends; the inner diameters of the high temperature section cover (10) and the middle temperature section cover (14) are larger than the outer diameter of the cooling cylinder (16); The section cover (10) is set on the high temperature section, and the medium temperature section cover (14) is set on the medium temperature section; the inlet end of the high temperature section air duct (502) is connected with the side of the high temperature section cover (10) The middle position is connected, the outlet end of the high-temperature section air induction pipe (502) is connected with the side of the air induction main pipe (501); the inlet end of the air introduction main pipe (501) is connected with the middle position of the side of the middle temperature section cover body (14) The outlet end of the air induction main pipe (501) is connected with the suction port of the fan (4); The air supply pipe heat exchange mechanism includes an air supply pipe, and the air supply pipe includes an air supply pipe insulation section (601) and an air supply pipe heating section (602); the inlet end of the air supply pipe insulation section (601) is connected to the fan The air outlets of (4) are connected, the outlet end of the air supply pipe insulation section (601) is connected with the inlet end of the air supply pipe heating section (602), and the outer surface of the air supply pipe insulation section (601) is wrapped with thermal insulation material The heating section of the air supply pipe (602) is located inside the cooling cylinder (16), the outlet end of the heating section of the air supply pipe (602) protrudes from the inlet of the cooling cylinder (16), and the heating section of the air supply pipe (602) The outlet end of the outlet port communicates with the air inlet of the burner (1) through a pipe. 2. According to claim 1, the waste heat annular partition wall recovery system for pellet calcined rotary kiln products is characterized in that: It also includes a feeding mechanism (9) arranged between the material outlet (8) and the inlet of the cooling cylinder (16). The feeding mechanism (9) includes a launder (901), a fixed jaw (902), The movable jaw (903) and the cam (904), the fixed jaw (902) is L-shaped, the fixed jaw (902) is fixed on the upper side of the launder (901), and the upper end of the movable jaw (903) is fixed on the The upper side of the launder (901) and the inner side of the movable jaw (903) are opposite to the fixed jaw (902); the cam (904) is located below the movable jaw (903) and the cam (904) and the movable jaw (903 ) in contact with the outer surface; the rotation center of the cam (904) is fixed with a rotating shaft, which is connected with the output shaft of the frequency conversion motor, and the movable jaw (903) swings through the rotation of the cam (904). 3. The waste heat annular partition wall recovery system for pellet calcined rotary kiln products according to claim 1, characterized in that: the middle temperature section cover (14) includes the middle temperature section upper cover and the middle temperature section lower cover, the middle temperature section The upper cover body and the lower cover body of the middle temperature section are both semi-cylindrical, and the side end faces of the upper cover body of the middle temperature section and the side end faces of the lower cover body of the middle temperature section are fixedly connected with connecting plates (13). The connecting plate (13) on the end face cooperates with the connecting plate (13) on the side end face of the lower cover body in the middle temperature section and is fixed together by connecting bolts (12); The structure of the high temperature section cover (10) is the same as that of the middle temperature section cover (14). 4. According to claim 1, the waste heat annular partition wall recovery system for pellet calcined rotary kiln products is characterized in that: The middle position on the middle temperature section cover body (14) is called the cover body expansion section (1401), and the inner diameter of the cover body expansion section (1401) is larger than the inner diameters on both sides of the middle position on the middle temperature section cover body (14); The middle position on the high temperature section cover (10) is called the high temperature section cover expansion section, and the inner diameter of the high temperature section cover expansion section is larger than the inner diameters on both sides of the high temperature section cover (10). 5. According to claim 1, the waste heat annular partition wall recovery system for pellet calcined rotary kiln products is characterized in that: The inner surface of the air supply pipe heating section (602) is welded with ribs (6021) at equal intervals along the circumference; the inner surface of the cooling cylinder (16) is welded with dispersion rods (1601) at equal intervals along the circumference ; The dispersing rod (1601) is L-shaped, and one end of the dispersing rod (1601) is welded to the inner surface of the cooling cylinder (16). 6. According to claim 2, the waste heat annular partition wall recovery system for pellet calcined rotary kiln products is characterized in that: The launder (901), fixed jaw (902), movable jaw (903) and cam (904) are all made of heat-resistant steel; During the swinging process of the movable jaw (903), the distance between the movable jaw (903) and the fixed jaw (902) is controlled within 20-50mm; The outer surface of the air supply pipe insulation section (601) is wrapped with insulation cotton. 7. According to claim 4, the waste heat annular partition wall recovery system for pellet calcined rotary kiln products is characterized in that: The central axis of the high-temperature section cover (10) coincides with the central axis of the high-temperature section, and the central axis of the medium-temperature section cover (14) coincides with the central axis of the medium-temperature section; the length of the high-temperature section cover (10) is 1500 ~ 2000mm, the length of the middle temperature section cover (14) is 3000 ~ 4500mm; The inner diameter of the upper cover expansion section (1401) of the cover (14) is larger than the outer diameter of the cooling cylinder (16) by 20-100 mm; the inner diameter of the cover expansion section (1401) is larger than the upper cover of the middle temperature section cover (14) The inner diameter of both sides of the body expansion section (1401) is 20-200 mm, and the inner diameter of the high-temperature section cover expansion section is larger than the inner diameter of the high-temperature section cover body (10) at both sides of the high-temperature section cover body expansion section of 20-200 mm; The length of the section (1401) is 200-1500mm, the length of the extended section of the high-temperature section cover is 200-1500mm; the inner diameter of the main air duct (501) and the air-induction pipe (502) of the high-temperature section is 200-500mm; The inner diameter of the section (601) and the heating section of the air supply pipe (602) is 150-500 mm, and the inner diameter of the outlet end of the heating section (602) of the air supply pipe is reduced to 50-100 mm. 8. According to claim 5, the system for recovering waste heat of rotary kiln products from granular material calcining with annular partition wall is characterized in that: The number of the ribs (6021) is 10-20, and the height of each rib (6021) is 30-80mm. 9. The annular partition wall type recovery system for the waste heat of rotary kiln products for granule calcining according to claim 1 or 2, characterized in that: a spraying device (7) is provided above the low temperature section. 10. A method for recovering the waste heat of a pellet calcined rotary kiln product with an annular partition wall, characterized in that it comprises the following steps, Step A: After being calcined in the rotary kiln (3), the pellets with a temperature of 800-900°C flow out from the discharge port (8), and enter the feed port of the cooling cylinder (16) through the feeding mechanism (9); wherein , the pellets are crushed in the feeding mechanism (9), the swing frequency of the movable jaw (903) is 2 to 5 times per second, the gap between the movable jaw (903) and the fixed jaw (902) during the swing process of the movable jaw (903) The distance is controlled at 20-50mm; Step B: The driving wheel of the cooling cylinder (15) drives the cooling cylinder (16) to rotate, so that the pellets at the inlet of the cooling cylinder (16) are transported to the outlet of the cooling cylinder (16); ) inside the heating and cooling cylinder (16) and the heating section of the air supply pipe (602), the average wall temperature of the high-temperature section on the cooling cylinder (16) is 550°C, the average wall temperature of the medium-temperature section is 400°C, and the average wall temperature of the low-temperature section 150°C; wherein, the pellets at the bottom of the cooling cylinder (16) are gathered by the dispersing rod (1601) at the bottom of the cooling cylinder (16) as the cooling cylinder (16) rotates, and the aggregated pellets are rotated to cool When the inner top of the cylinder (16) falls freely, the pellets are gathered by the dispersing rod (1601) again after falling freely, and then fall freely, and reciprocate in this way until the pellets are discharged from the outlet of the cooling cylinder (16); Step C: Turn on the fan (4), and the fan (4) draws the air in the annular gap between the high temperature section cover (10) and the high temperature section through the high temperature section air duct (502), and the high temperature section cover (10) and the high temperature section The air in the annular gap between the high-temperature sections conducts convective heat exchange with the wall surface of the high-temperature section during the extraction process, and the air temperature rises; The air in the annular gap between the intermediate temperature section cover body (14) and the intermediate temperature section conducts convective heat exchange with the wall surface of the intermediate temperature section during the extraction process, and the air temperature rises; Step D: The air drawn by the fan (4) through the high-temperature section air-induction pipe (502) and the air-induction main pipe (501) is mixed and sent to the air supply pipe heating section (602) for further heating, and the air temperature rises again; among them, The inner surface of the heating section of the air supply pipe (602) is welded with ribbed plates (6021) at equal intervals along the circumference; Step E: The heated air in the heating section (602) of the air supply pipe is sent to the air inlet of the burner (1) through the pipe to supply preheated air for flame combustion in the combustion chamber (2).