CN118310325B - A method for recovering heat from high-temperature materials after calcination in a rotary kiln - Google Patents

Abstract

The present invention relates to the technical field of rotary kilns, and in particular to a method for recovering heat from high-temperature materials after calcination in a rotary kiln. The system includes a heat exchanger, a cooling kiln, a first three-way chute, a second three-way chute, and a straight chute. The heat exchanger and the cooling kiln are located below the rotary kiln. The discharge port of the rotary kiln is connected to an interface of the first three-way chute. The other two interfaces of the first three-way chute are provided with valves, and are respectively connected to the feed port of the heat exchanger and an interface of the second three-way chute through the straight chute. Among the other two interfaces of the second three-way chute, one interface is connected to the heat exchanger, and the other interface is connected to the feed port of the cooling kiln. The interface of the second three-way chute leading to the heat exchanger is provided with a valve. By designing a heat recovery method with a heat exchanger and a cooling kiln, a combined heat exchange method is realized, which not only reasonably controls the size of the required heat exchanger, but also has a high heat recovery efficiency for high-temperature materials, realizes maximum heat recovery, and reduces production costs.

Description

A method for recovering heat from high-temperature materials after calcination in a rotary kiln

Technical Field

The invention relates to the technical field of rotary kilns, and in particular to a method for recovering heat from high-temperature materials after calcination in a rotary kiln.

Background Art

In 2022, the domestic production of calcined petroleum coke has reached nearly 30 million tons. Although most of them adopt the tank furnace calcination process, a small part still adopts the rotary kiln calcination process, especially at the source of petroleum coke production in petrochemical plants. In addition, the rotary kiln process is also used for the calcination of needle coke in the special carbon field. The temperature of calcined coke after calcination in the rotary kiln is as high as 1300~1350℃. In order to cool the high-temperature material, the direct cooling method of spraying in the cooling kiln is generally adopted. This cooling method not only wastes a lot of water resources, but also generates a lot of steam during the cooling process. The steam directly enters the post-combustion chamber of the rotary kiln, causing system pressure loss and affecting the production process. In the current situation where high-sulfur coke is dominant, the desulfurization and denitrification system will also greatly increase production costs due to the increase in flue gas volume.

Based on the above reasons, heat exchangers can be used to recover heat from high-temperature materials in rotary kilns. However, if heat exchangers are used to recover all the heat from high-temperature calcined coke, a very large heat exchange area is required, which is not feasible in terms of engineering space and process configuration. Indirect water cooling using an indirect built-in coil structure in the cooling kiln jacket can also be used, but the recovered heat can only produce more hot water, and only a small part of the hot water required for engineering and life is needed. The excess hot water has no suitable use, and the heat cannot be effectively recovered.

Summary of the invention

In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a heat recovery system and method for high-temperature materials after calcination in a rotary kiln. By designing a heat recovery system with a heat exchanger and a cooling kiln, a combined heat exchange mode is realized, which not only reasonably controls the size of the required heat exchanger, but also has a high heat recovery efficiency for high-temperature materials, thereby realizing maximum heat recovery and reducing production costs.

In order to achieve the above object, the main technical solutions adopted by the present invention include:

A heat recovery system for high-temperature materials after calcination in a rotary kiln comprises a heat exchanger, a cooling kiln, a first three-way chute, a second three-way chute and a straight chute. The heat exchanger and the cooling kiln are located below the rotary kiln. The discharge port of the rotary kiln is connected to an interface of the first three-way chute. The other two interfaces of the first three-way chute are provided with valves and are respectively connected to the feed port of the heat exchanger and an interface of the second three-way chute through the straight chute. Of the other two interfaces of the second three-way chute, one interface is connected to the heat exchanger, and the other interface is connected to the feed port of the cooling kiln. The interface of the second three-way chute leading to the heat exchanger is provided with a valve.

By designing a heat recovery system with a heat exchanger and a cooling kiln, a combined heat exchange method is realized. The high-temperature material enters the heat exchanger after calcination in the rotary kiln, and the medium-temperature material after heat exchange is discharged through the heat exchanger to the cooling kiln for further cooling. This not only reasonably controls the size of the required heat exchanger, but also has a high efficiency in heat recovery for high-temperature materials. The high-quality heat recovered by the heat exchanger can be used to produce steam for power generation, etc., and the low-quality heat recovered by the cooling kiln can be used to produce hot water for production and life, etc., thereby maximizing heat recovery.

The heat recovery system can realize both the combined cooling method of the heat exchanger and the cooling kiln, and the single cooling method of the cooling kiln. It can be flexibly adjusted according to the actual operation of the system, which is beneficial to improving the operation efficiency of the entire system.

Furthermore, it also includes an elevator, the heat exchanger discharge port is located lower than the cooling kiln, the heat exchanger discharge port is connected to the feed port of the elevator, the discharge port of the elevator is connected to the interface of the second three-way chute, and the discharge port of the elevator is located higher than the feed port of the cooling kiln.

By setting up a hoist, the materials discharged from the heat exchanger can be easily entered into the cooling kiln without digging the cooling kiln foundation, and the length between the first three-way chute and the second three-way chute is reduced, avoiding the situation where the materials in the rotary kiln are directly discharged into the cooling kiln and are broken due to the large height difference.

Furthermore, it also includes a screw conveyor, and the discharge port of the heat exchanger is connected to the feed port of the elevator through the screw conveyor.

A screw conveyor is provided to facilitate the material discharged from the heat exchanger to be fed into the cooling kiln.

Furthermore, the discharge port of the elevator is located higher than the feed port of the cooling kiln.

By setting the discharge port of the elevator higher than the feed port of the cooling kiln, it is convenient for the material output by the elevator to enter the cooling kiln through the second three-way chute and the straight chute.

Furthermore, a spiral distributor is provided on the top of the heat exchanger.

A spiral distributor is provided to evenly distribute the high-temperature material entering the heat exchanger.

Furthermore, the spiral distributor is of a jacket structure, wherein the outer shell and the internal spiral blades of the spiral distributor are provided with a jacket layer along their outer shape, cooling water flows through the jacket layer, and the cooling water pipeline of the spiral distributor is independent of the pipeline of the heat exchanger.

By setting the spiral distributor as a jacket structure, on the one hand, heat is exchanged for high-temperature materials, and on the other hand, the spiral distributor is cooled, thereby extending its service life.

Furthermore, the cooling kiln is a coil cooling kiln, and the cooling medium is water.

Furthermore, the heat recovery system is sealed.

By adopting sealing treatment, the entry of oxygen is reduced and oxidation of high-temperature materials is prevented.

A method for recovering heat from high-temperature materials after calcination in a rotary kiln adopts a heat recovery system for high-temperature materials after calcination in a rotary kiln. When a heat exchanger works normally, the valve from a first three-way chute to a second three-way chute is closed, and the valves from the first three-way chute and the second three-way chute to the heat exchanger are opened, so that the high-temperature materials first enter the heat exchanger after being discharged from the rotary kiln, and then enter the cooling kiln.

By designing a heat recovery method, high-temperature materials are calcined in a rotary kiln and then enter the heat exchanger. The medium-temperature materials after heat exchange are discharged through the heat exchanger to the cooling kiln for further cooling. The heat recovery efficiency of high-temperature materials is high. The high-quality heat recovered by the heat exchanger can be used to produce steam for power generation, etc. The low-quality heat recovered by the cooling kiln can be used to produce hot water for production and life, etc., thereby maximizing heat recovery.

Furthermore, when the heat exchanger is overhauled, the valve from the first three-way chute to the second three-way chute is opened, and the valves from the first three-way chute and the second three-way chute to the heat exchanger are closed, so that the high-temperature material can directly enter the cooling kiln after being discharged from the rotary kiln.

By adjusting the valve opening and closing, when the heat exchanger is under maintenance, high-temperature materials can directly enter the cooling kiln, realizing heat recovery of high-temperature materials, avoiding maintenance shutdowns and improving recovery efficiency.

The beneficial effects of the present invention are:

The present invention provides a heat recovery system and method for high-temperature materials after calcination in a rotary kiln. By designing a heat recovery system with a heat exchanger and a cooling kiln, a combined heat exchange mode is realized. The high-temperature materials enter the heat exchanger after calcination in the rotary kiln, and the medium-temperature materials after heat exchange are discharged to the cooling kiln through the heat exchanger for further cooling. This not only reasonably controls the size of the required heat exchanger, the heat exchanger occupies less space, and has high heat recovery efficiency for high-temperature materials. The high-quality heat recovered by the heat exchanger can be used to produce steam for power generation, etc., and the low-quality heat recovered by the cooling kiln can be used to produce hot water for production and life, etc., thereby maximizing heat recovery and reducing production costs.

The heat recovery system can realize both the combined cooling method of the heat exchanger and the cooling kiln, and the single cooling method of the cooling kiln. It can be flexibly adjusted according to the actual operation of the system, which is beneficial to improving the operation efficiency of the entire system.

At the same time, a method for recovering heat from high-temperature materials after calcination in a rotary kiln is provided, which not only has all the beneficial effects of the above-mentioned heat recovery system, but also can realize heat recovery of high-temperature materials by opening and closing valves when the heat exchanger is under maintenance, avoiding maintenance shutdown and improving recovery efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a heat recovery system for high-temperature materials after calcination in a rotary kiln according to the present invention.

In the figure: 1. rotary kiln; 2. first three-way chute; 3. straight chute; 4. spiral distributor; 5. heat exchanger; 6. screw conveyor; 7. elevator; 8. second three-way chute; 9. cooling kiln.

DETAILED DESCRIPTION

In order to better explain the present invention and facilitate understanding, the present invention is described in detail below in conjunction with the accompanying drawings through specific embodiments. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a clearer and more thorough understanding of the present invention and to be able to fully convey the scope of the present invention to those skilled in the art.

As shown in FIG1 , a heat recovery system for high-temperature materials after calcination in a rotary kiln comprises a heat exchanger 5, a cooling kiln 9, a first three-way chute 2, a second three-way chute 8, and a straight chute 3. The heat exchanger 5 and the cooling kiln 9 are located below the rotary kiln 1. The discharge port of the rotary kiln 1 is connected to an interface of the first three-way chute 2. The other two interfaces of the first three-way chute 2 are provided with valves, and are respectively connected to the feed port of the heat exchanger 5 and an interface of the second three-way chute 8 through the straight chute 3. Of the other two interfaces of the second three-way chute 8, one interface is connected to the heat exchanger 5, and the other interface is connected to the feed port of the cooling kiln 9. The interface of the second three-way chute 8 leading to the heat exchanger 5 is provided with a valve.

By designing a heat recovery system with a heat exchanger 5 and a cooling kiln 9, a combined heat exchange method is realized. The high-temperature material enters the heat exchanger 5 after being calcined in the rotary kiln 1, and the medium-temperature material after heat exchange is discharged from the heat exchanger 5 to the cooling kiln 9 for further cooling, so that the size of the required heat exchanger 5 is reasonably controlled. The length, width and height of the heat exchanger 5 used in the system are respectively about 6m, 3m and 6m. If only the heat exchanger 5 is used to recover all the heat of the high-temperature calcined coke, the size of the heat exchanger 5 is 8-10 times of the size, and the heat recovery efficiency of the high-temperature material is high. The heat exchanger 5 recovers most of the heat of the high-temperature material for generating steam, and the steam can be used for power generation, etc. After heat exchange, the high-temperature material becomes a medium-temperature material; the cooling kiln 9 is used to recover the heat of the medium-temperature material to produce a small amount of hot water, which is used for production and life, such as boiler economizer water intake, heating, bathing, etc., to achieve maximum heat recovery.

In this embodiment, the product after the rotary kiln 1 is heated is high-temperature calcined coke, with a temperature of 1300-1350°C. After heat exchange in the heat exchanger 5, it becomes medium-temperature calcined coke of about 600°C, and simultaneously generates 3.8MPa, 450°C high-temperature and high-pressure steam. After the medium-temperature calcined coke enters the cooling kiln 9, it is indirectly heat exchanged with water, and the temperature drops to below 100°C, generating hot water of 60-80°C.

The heat recovery system can realize both the combined cooling method of the heat exchanger 5 and the cooling kiln 9 and the single cooling method of the cooling kiln 9, and can be flexibly adjusted according to the actual operation of the system, which is beneficial to improving the operation efficiency of the entire system.

Specifically, it also includes an elevator 7, the discharge port of the heat exchanger 5 is located lower than the cooling kiln 9, the discharge port of the heat exchanger 5 is connected to the feed port of the elevator 7, the discharge port of the elevator 7 is connected to the interface of the second three-way chute 8, and the discharge port of the elevator 7 is located higher than the feed port of the cooling kiln 9.

By setting the elevator 7, the material discharged from the heat exchanger 5 can be easily entered into the cooling kiln 9 without digging the foundation of the cooling kiln 9, and the length between the first three-way chute 2 and the second three-way chute 8 is reduced, avoiding the situation where the material in the rotary kiln 1 is directly discharged into the cooling kiln 9 and the material is broken due to the large height difference.

Specifically, it also includes a screw conveyor 6 , and the discharge port of the heat exchanger 5 is connected to the feed port of the elevator 7 through the screw conveyor 6 .

The screw conveyor 6 is provided to facilitate the material discharged from the heat exchanger 5 to be fed into the cooling kiln 9 .

Specifically, the discharge port of the elevator 7 is located higher than the feed port of the cooling kiln 9 .

By arranging the discharge port of the elevator 7 to be higher than the feed port of the cooling kiln 9 , it is convenient for the material output by the elevator 7 to enter the cooling kiln 9 through the second three-way chute 8 and the straight chute 3 .

Specifically, a spiral distributor 4 is provided on the top of the heat exchanger 5 .

The spiral distributor 4 is provided to evenly distribute the high-temperature material entering the heat exchanger 5 .

Specifically, the spiral distributor 4 is a jacket structure, in which the outer shell and the internal spiral blades of the spiral distributor 4 are provided with a jacket layer along their outer shape, and cooling water flows through the jacket layer. The cooling water pipeline of the spiral distributor 4 is independent of the pipeline of the heat exchanger 5.

By setting the spiral distributor 4 as a jacket structure, on the one hand, heat is exchanged for the high-temperature material, and on the other hand, the spiral distributor 4 is cooled, thereby extending its service life.

Specifically, the cooling kiln 9 is a coil cooling kiln, and the cooling medium is water.

Specifically, the heat recovery system adopts a sealed process.

By adopting sealing treatment, the entry of oxygen is reduced and oxidation of high-temperature materials is prevented.

Specifically, the first three-way slide pipe 2, the second three-way slide pipe 8 and the straight slide pipe 3 are made of heat-resistant high-temperature castable materials, and rivets are welded first during construction.

Specifically, the elevator 7 is a bucket elevator.

A method for recovering heat from high-temperature materials after calcination in a rotary kiln adopts a heat recovery system for high-temperature materials after calcination in a rotary kiln. When a heat exchanger 5 works normally, the valve from the first three-way chute 2 to the second three-way chute 8 is closed, and the valves from the first three-way chute 2 and the second three-way chute 8 to the heat exchanger 5 are opened, so that the high-temperature materials enter the heat exchanger 5 first after being discharged from the rotary kiln 1, and then enter the cooling kiln 9.

By designing a heat recovery method, the high-temperature material is calcined in the rotary kiln 1 and then enters the heat exchanger 5, and the medium-temperature material after heat exchange is discharged through the heat exchanger 5 to the cooling kiln 9 for further cooling. The heat recovery efficiency of the high-temperature material is high, and the high-quality heat recovered by the heat exchanger 5 can be used to produce steam for power generation, etc., and the low-quality heat recovered by the cooling kiln 9 can be used to produce hot water for production and life, etc., thereby realizing maximum heat recovery.

Specifically, when the heat exchanger 5 is overhauled, the valve from the first three-way chute 2 to the second three-way chute 8 is opened, and the valves from the first three-way chute 2 and the second three-way chute 8 to the heat exchanger 5 are closed, so that the high-temperature material can directly enter the cooling kiln 9 after being discharged from the rotary kiln 1.

By adjusting the opening and closing of the valve, when the heat exchanger 5 is under maintenance, the high-temperature material directly enters the cooling kiln 9, so as to realize heat recovery of the high-temperature material, avoid maintenance shutdown, and improve recovery efficiency.

The heat exchanger 5, spiral distributor 4 and other equipment involved in this case are all non-standard equipment. Their structures and raw materials are not complicated and are well-known technologies in the art. Their specific structures will not be described here.

Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims (8)

1. A method for recovering heat from high-temperature materials after calcination in a rotary kiln, characterized in that it comprises a heat exchanger (5), a cooling kiln (9), a first three-way chute (2), a second three-way chute (8), and a straight chute (3), wherein the heat exchanger (5) and the cooling kiln (9) are located below the rotary kiln (1), the discharge port of the rotary kiln (1) is connected to an interface of the first three-way chute (2), the other two interfaces of the first three-way chute (2) are provided with valves, and are respectively connected to the feed port of the heat exchanger (5) and an interface of the second three-way chute (8) through the straight chute (3), one of the other two interfaces of the second three-way chute (8) is connected to the heat exchanger (5), and the other interface is connected to the feed port of the cooling kiln (9), and the interface of the second three-way chute (8) leading to the heat exchanger (5) is provided with a valve; When the heat exchanger (5) is operating normally, the valve from the first three-way chute (2) to the second three-way chute (8) is closed, and the valves from the first three-way chute (2) and the second three-way chute (8) to the heat exchanger (5) are opened, so that the high-temperature material, after being discharged from the rotary kiln (1), first enters the heat exchanger (5) and then enters the cooling kiln (9); When the heat exchanger (5) is under maintenance, the valve from the first three-way chute (2) to the second three-way chute (8) is opened, and the valves from the first three-way chute (2) and the second three-way chute (8) to the heat exchanger (5) are closed, so that the high-temperature material can be directly discharged from the rotary kiln (1) into the cooling kiln (9). 2. A method for recovering heat from high-temperature materials after calcination in a rotary kiln as described in claim 1, characterized in that: it also includes an elevator (7), the discharge port of the heat exchanger (5) is located lower than the cooling kiln (9), the discharge port of the heat exchanger (5) is connected to the feed port of the elevator (7), the discharge port of the elevator (7) is connected to the interface of the second three-way chute (8), and the discharge port of the elevator (7) is located higher than the feed port of the cooling kiln (9). 3. A method for recovering heat from high-temperature materials after calcination in a rotary kiln as claimed in claim 2, characterized in that it also includes a screw conveyor (6), and the discharge port of the heat exchanger (5) is connected to the feed port of the elevator (7) through the screw conveyor (6). 4. A method for recovering heat from high-temperature materials after calcination in a rotary kiln as claimed in claim 2, characterized in that the discharge port of the elevator (7) is located higher than the feed port of the cooling kiln (9). 5. A method for recovering heat from high-temperature materials after calcination in a rotary kiln as claimed in claim 1, characterized in that a spiral distributor (4) is provided on the top of the heat exchanger (5). 6. A method for recovering heat from high-temperature materials after calcination in a rotary kiln as claimed in claim 5, characterized in that: the spiral distributor (4) is a jacket structure, and the jacket structure is that the outer shell and the internal spiral blades of the spiral distributor (4) are both provided with a jacket layer along their outer shape, and cooling water flows through the jacket layer, and the cooling water pipeline of the spiral distributor (4) is independent of the pipeline of the heat exchanger (5). 7. A method for recovering heat from high-temperature materials after calcination in a rotary kiln as claimed in claim 1, characterized in that the cooling kiln (9) is a coil cooling kiln and the cooling medium is water. 8. A method for recovering heat from high temperature materials after calcination in a rotary kiln as claimed in any one of claims 1 to 7, characterized in that the heat recovery system is sealed.