Air and all-oxygen dual-mode grate cooler

Abstract

The present disclosure relates to the technical field of cement production apparatuses, in particular to an air and full-oxygen dual-mode grate cooler which comprises a housing, a fixed wall plate and a grate, the grate comprising a first grate section and a second grate section, the housing being of a special-shaped structure and forming a sealed chamber between the tail end of the first grate section and the head end of the second grate section; in an air mode, in the process in which a clinker moves from the first grate section to the second grate section through the sealed chamber, the clinker occupying a small part of the section of the sealed chamber, and other spaces in the sealed chamber forming a communication channel between the upper space of the first grate section and the upper space of the second grate section; in a full-oxygen mode, the sealed chamber is filled with the clinker to form a material seal, so as to divide the upper space of the first grate section and the upper space of the second grate section into two independent cooling zones. The grate cooler achieves air and all-oxygen dual-mode operation, and can easily switch from an air mode to an all-oxygen mode, thus improving the operation flexibility of the whole firing system.

Description

Air and full oxygen dual-mode grate cooler

[0001] Related applications

[0002] This disclosure claims priority to a Chinese patent application filed with the Patent Office of China on September 12, 2023, with application number CN 202311169474.4 and invention name “Air, full oxygen dual-mode grate cooler”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to the technical field of cement production equipment, and in particular to an air and full oxygen dual-mode grate cooler. Background Art

[0004] In the context of carbon emission reduction in the cement industry, oxyfuel combustion is the primary technical approach for carbon emission reduction, offering broad prospects for energy conservation and carbon reduction in the cement industry. In oxyfuel combustion systems, grate coolers are key components of the system. The cement firing process typically begins in air mode, then gradually switches to oxyfuel combustion once the system stabilizes. This requires switching between air and oxyfuel modes. In dual-mode, grate coolers must provide both clinker cooling and independent zone cooling, ensuring excellent airtightness. Based on these requirements, our company proposes this design solution to meet these requirements.

[0005] Summary of the Invention

[0006] In response to the above problems, an embodiment of the present disclosure provides an air and full oxygen dual-mode grate cooler.

[0007] One aspect of the present disclosure provides an air and full oxygen dual-mode grate cooler, comprising a shell, a fixed wall plate and a grate bed, the grate bed comprising a first-stage grate bed and a second-stage grate bed, the shell having a special-shaped structure forming a sealing groove between the tail end of the first-stage grate bed and the head end of the second-stage grate bed; in the air mode, during the process of clinker passing from the first-stage grate bed through the sealing groove into the second-stage grate bed, the clinker occupies a small part of the cross-section of the sealing groove, and the other space in the sealing groove forms a connecting channel between the upper space of the first-stage grate bed and the upper space of the second-stage grate bed; in the full oxygen mode, the sealing groove is filled with clinker to form a material seal, dividing the upper space of the first-stage grate bed and the upper space of the second-stage grate bed into two independent cooling zones.

[0008] Compared with the prior art, the beneficial effects of the present invention are: the grate cooler meets the requirements of air and full oxygen dual-mode operation, and can be easily switched from air mode to full oxygen mode, thereby improving the operational flexibility of the entire firing system; at the same time, the grate cooler includes a first-stage grate bed and a second-stage grate bed, and a sealing groove is provided between the two sections. By controlling the amount of clinker in the sealing groove, the first and second sections of the grate cooler can be separated in the full oxygen mode, so that the gases in the upper parts of the two sections are independent, realizing the functions of independent partition cooling and good airtightness; in the air mode, no material is stored in the sealing groove, which is used to connect the upper gases between the two sections. The high-temperature air in the two sections can enter the kiln and the decomposition furnace respectively according to the required amount and be discharged from the exhaust gas outlet of the grate cooler, thereby solving the problem of large area requirement for the first-stage grate bed of the grate cooler in the air mode and reducing equipment investment.

[0009] Optionally, the first grate bed and the second grate bed have the same width, the first grate bed occupies 30-40% of the designed length of the grate bed, and the second grate bed occupies 60-70% of the designed length of the grate bed.

[0010] Optionally, blocks are provided on the front and rear sides of the sealing groove; the addition of blocks is beneficial to the flow of clinker, and at the same time less clinker can be used to form a sealed isolation and reduce the pressure of the clinker on the grate bed below.

[0011] Optionally, a crusher is provided at the tail end of the second-stage grate bed; when the crusher is arranged at the tail end of the second-stage grate bed, compared with arranging the crusher between the two grate beds, the crusher operates at a lower clinker temperature, which reduces the requirements for the crusher material and extends the service life of the crusher.

[0012] Optionally, a level meter is provided on the shell and above the sealing groove; the level meter can be used to detect the amount of clinker in the sealing groove to ensure that the sealing groove is full of clinker in the air mode, thereby ensuring the sealing effect.

[0013] Optionally, the grate plate located below the sealing groove outlet in the second-stage grate bed is a whole plate, and the grate plates in other areas are mesh plates with through holes; the grate plate below the sealing groove has no openings, and the blown-in cold air passes through the bottom of the grate plate to cool the grate plate. The grate plate after passing the sealing groove outlet is provided with openings, and the air enters the grate cooler from the grate plate to cool the clinker, thereby avoiding the air below the sealing groove in the second-stage grate bed from passing through the sealing groove into the first-stage grate bed.

[0014] Optionally, an ash unloading system is provided at the bottom of the shell, and a disc conveyor is provided below the ash unloading system, wherein the ash unloading system includes an ash unloading hopper arranged at intervals at the bottom of the shell and an ash unloading pipe arranged vertically at the bottom of the ash unloading hopper.

[0015] Optionally, each air chamber of the grate cooler is provided with one air supply duct, two air supply ducts are provided at the fixed wall panel, and a cooling fan is provided on the air supply duct, wherein the air inlet of the cooling fan for supplying air to a section of the grate bed and the fixed wall panel is connected to two ducts, one is an air duct, and the other is a high-concentration carbon dioxide and oxygen duct. Butterfly valves are provided on the two ducts. In the air mode, the butterfly valve on the air duct is open and the butterfly valves on the high-concentration carbon dioxide and oxygen ducts are closed. In the full oxygen mode, the butterfly valve on the air duct is closed and the butterfly valves on the high-concentration carbon dioxide and oxygen ducts are opened. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of the present disclosure, constitute a part of the present disclosure, and do not constitute a limitation of the present disclosure. In the drawings:

[0017] FIG1 is a schematic structural diagram of a first air and full oxygen dual-mode grate cooler provided in an embodiment of the present disclosure;

[0018] FIG2 is a schematic structural diagram of a second air and full oxygen dual-mode grate cooler provided in an embodiment of the present disclosure;

[0019] FIG3 is a schematic diagram of an air supply system of an air and full oxygen dual-mode grate cooler provided in an embodiment of the present disclosure.

[0020] Among them, there are shell 1, fixed wall panel 2, first-stage grate bed 3, second-stage grate bed 4, sealing groove 5, grate cooler inlet 6, exhaust gas outlet 7, block 8, crusher 9, level meter 10, ash unloading system 11, disc conveyor 12, air supply duct 13, cooling fan 14, air duct 15, high-concentration carbon dioxide and oxygen duct 16, and butterfly valve 17. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in conjunction with the embodiments and drawings. Here, the illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure, but are not intended to limit the present disclosure.

[0022] Referring to Figure 1, an air and full oxygen dual-mode grate cooler provided in an embodiment of the present disclosure includes a shell 1, a fixed wall panel 2 and a grate bed, the grate bed includes a first-stage grate bed 3 and a second-stage grate bed 4, and the shell 1 has a special-shaped structure to form a sealing groove 5 between the tail end of the first-stage grate bed 3 and the head end of the second-stage grate bed 4; in the air mode, when the clinker enters the second-stage grate bed 4 from the first-stage grate bed 3 through the sealing groove 5, the clinker occupies a small part of the cross-section of the sealing groove 5, and the other space in the sealing groove 5 forms a connecting channel between the upper space of the first-stage grate bed 3 and the upper space of the second-stage grate bed 4; in the full oxygen mode, the sealing groove 5 is filled with clinker to form a material seal, dividing the upper space of the first-stage grate bed 3 and the upper space of the second-stage grate bed 4 into two independent cooling zones.

[0023] During implementation, the shell 1 as a whole can be in a Z-shaped structure, with a certain height difference designed between the first-stage grate bed 3 and the second-stage grate bed 4. The sealing groove 5 is a material conveying channel connected between the tail end of the first-stage grate bed 3 and the head end of the second-stage grate bed 4 and has a certain height difference; the grate cooler inlet 6 is arranged on the shell 1 above the fixed wall panel 2, and the exhaust gas outlet 7 is arranged on the shell 1 above the second-stage grate bed 4.

[0024] The first grate bed 3 and the second grate bed 4 have the same width. The first grate bed 3 occupies 30-40% of the designed length of the grate bed, and the second grate bed 4 occupies 60-70% of the designed length of the grate bed.

[0025] 2 , blocks 8 are provided on the front and rear sides of the sealing groove 5; the cross section of the block 8 may be triangular; the addition of the block 8 is beneficial to the flow of the clinker, and at the same time, less clinker can be used to form a sealed isolation, thereby reducing the pressure of the clinker on the grate bed below.

[0026] A crusher 9 is provided at the tail end of the second-stage grate bed 4; the crusher 9 is arranged at the tail end of the second-stage grate bed 4. Compared with arranging the crusher 9 between the two grate beds, the crusher 9 operates at a lower clinker temperature, which reduces the requirements for the material of the crusher 9 and extends the service life of the crusher 9.

[0027] A material level meter 10 is provided on the housing 1 and above the sealing groove 5; the material level meter 10 can be used to detect the amount of clinker in the sealing groove 5 to ensure that the sealing groove 5 is full of clinker in the air mode, thereby ensuring the sealing effect.

[0028] The grate plate located below the outlet of the sealing groove 5 in the second-stage grate bed 4 is an integral plate, and the grate plates in other areas are mesh plates with through holes; the grate plate below the sealing groove 5 has no openings, and the cold air blown in passes through the lower part of the grate plate to cool the grate plate. The grate plate after passing the outlet of the sealing groove 5 is provided with openings, and the air enters the grate cooler from the grate plate to cool the clinker, avoiding the air below the sealing groove 5 in the second-stage grate bed 4 from passing through the sealing groove 5 into the first-stage grate bed 3, thereby enhancing the sealing performance.

[0029] An ash unloading system 11 is provided at the bottom of the shell 1 , and a disc conveyor 12 is provided below the ash unloading system 11 , wherein the ash unloading system 11 includes an ash unloading hopper spaced apart at the bottom of the shell 1 and an ash unloading pipe vertically provided at the bottom of the ash unloading hopper.

[0030] Referring to the air supply system shown in FIG3 , each air chamber of the grate cooler is provided with an air supply duct 13, two air supply ducts 13 are provided at the fixed wall plate 2, and a cooling fan 14 is provided on the air supply duct 13. The air inlet of the cooling fan 14 for supplying air to a section of the grate bed 3 and the fixed wall plate 2 is connected to two pipes, one for the air duct 15 and the other for the high-concentration carbon dioxide and oxygen pipe 16. A butterfly valve 17 is provided on the two pipes. In the air mode, the butterfly valve 17 on the air duct 15 is open, and the butterfly valve 17 on the high-concentration carbon dioxide and oxygen pipe 16 is closed. In the full oxygen mode, the butterfly valve 17 on the air duct 15 is closed, and the butterfly valve 17 on the high-concentration carbon dioxide and oxygen pipe 16 is opened.

[0031] During the cement burning process, the clinker is discharged from the rotary kiln and fed into the fixed wall plate 2 at the front end of the first grate bed 3 of the grate cooler. After that, the clinker is transported from the head end of the first grate bed 3 to the outlet at the tail end of the first grate bed 3.

[0032] In the air mode, the butterfly valve 17 on the air pipe 15 is opened, and the butterfly valve 17 on the high-concentration carbon dioxide and oxygen pipe 16 is closed; the clinker passes through the sealing groove 5 and is fed into the second-stage grate bed 4. It is then transported from the head end of the second-stage grate bed 4 to the outlet at the tail end of the second-stage grate bed 4 and then sent to the crusher 9, where it is crushed and discharged;

[0033] As the clinker passes through the grate bed, the cooling fan 14 blows in room-temperature air to cool the clinker. The air exchanges heat with the clinker to form high-temperature air, which then enters between the upper part of the grate bed material layer and the shell. The high-temperature air above the first-stage grate bed 3 selectively enters the kiln head cover, the kiln, and the decomposition furnace as needed to achieve heat recovery and provide oxygen for combustion in the kiln and the decomposition furnace. The high-temperature air above the second-stage grate bed 4 is discharged through the exhaust gas outlet 7.

[0034] In the full oxygen mode, the butterfly valve 17 on the air pipe 15 is closed, and the butterfly valve 17 on the high-concentration carbon dioxide and oxygen pipe 16 is opened; after the clinker enters the sealing tank 5, it is accumulated in the sealing tank 5, and the level meter 10 is used to detect the amount of clinker in the sealing tank 5. When it is determined that the clinker in the sealing tank 5 is consistent with the height of the upper layer of the first-stage grate bed 3, the clinker fills the sealing tank 5, and the upper space of the first-stage grate bed 3 and the second-stage grate bed 4 are separated to form two independent cooling partitions. Thereafter, the second-stage grate bed 4 begins to transport the clinker to the rear side; the first-stage grate bed 3 corresponds to the cooling fan 14 that blows low-temperature, high-concentration carbon dioxide and oxygen into the clinker to cool the clinker. After the high-concentration carbon dioxide and oxygen exchange heat with the clinker, they enter between the upper part of the first-stage grate bed 3 and the shell, and select to enter the kiln head cover, the kiln and the decomposition furnace as needed to provide oxygen for combustion in the kiln and the decomposition furnace. Heat recovery and flame temperature control are achieved; when the clinker passes through the second-stage grate bed 4, the corresponding cooling fan 14 blows in room temperature air, which exchanges heat with the clinker to form low-temperature hot air and is discharged from the exhaust gas outlet.

[0035] The solution provided by the present disclosure is as follows: 1. The grate cooler can operate in both air and full oxygen modes and can be easily switched from air mode to full oxygen mode, thereby improving the operational flexibility of the entire firing system;

[0036] 2. The grate cooler consists of a first-stage grate bed and a second-stage grate bed. A sealing groove is set between the two sections. By controlling the amount of clinker in the sealing groove, the first and second sections of the grate cooler can be separated in the full oxygen mode, so that the gases in the upper parts of the two sections are independent, realizing the functions of independent zone cooling and good airtightness;

[0037] 3. In air mode, there is no material stored in the sealing groove, which is used to connect the upper gas between the two sections. The high-temperature air in the two sections can enter the kiln and decomposition furnace respectively according to the required amount and be discharged from the exhaust gas outlet of the grate cooler, which solves the problem of large demand for the grate bed area of ​​the first section of the grate cooler in air mode and reduces equipment investment.

[0038] 4. Adding a block in the sealing groove is beneficial to the flow of clinker, and at the same time, less clinker can be used to form a sealed isolation and reduce the pressure of the clinker on the grate bed below;

[0039] 5. The crusher is arranged at the end of the second-stage grate bed. Compared with the crusher arranged between the two grate beds, the crusher works at a lower clinker temperature, which reduces the requirements for the crusher material and extends the service life of the crusher.

[0040] 6. There are no openings on the grate plate below the sealing groove. The cold air blown in passes through the bottom of the grate plate to cool the grate plate. There are openings on the grate plate after passing the sealing groove outlet. The air enters the grate cooler from the grate plate to cool the clinker, avoiding the air below the sealing groove in the second-stage grate bed from passing through the sealing groove into the first-stage grate bed.

[0041] The above description is only a preferred embodiment of the present disclosure and is not intended to limit the scope of protection of the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure are included in the scope of protection of the present disclosure.

Claims

1. An air and full oxygen dual-mode grate cooler, comprising a shell, a fixed wall plate and a grate bed, wherein the grate bed comprises a first-stage grate bed and a second-stage grate bed, characterized in that: The shell has a special-shaped structure to form a sealing groove between the tail end of the first grate bed and the head end of the second grate bed; in the air mode, when the clinker enters the second grate bed from the first grate bed through the sealing groove, the clinker occupies a small part of the cross section of the sealing groove, and the other space in the sealing groove forms a connecting channel between the upper space of the first grate bed and the upper space of the second grate bed; In the full oxygen mode, the sealing tank is filled with clinker to form a material seal, dividing the upper space of the first grate bed and the upper space of the second grate bed into two independent cooling zones; Stoppers are provided on the front and rear sides of the sealing groove; The grate plate located below the outlet of the sealing groove in the second-stage grate bed is an integral plate, and the grate plates in other areas are mesh plates with through holes; Each air chamber of the grate cooler is provided with one air supply duct, and two air supply ducts are provided at the fixed wall panel. A cooling fan is provided on the air supply duct, wherein the air inlet of the cooling fan for supplying air to a section of the grate bed and the fixed wall panel is connected to two ducts, one is an air duct, and the other is a high-concentration carbon dioxide and oxygen duct. Butterfly valves are provided on the two ducts. In the air mode, the butterfly valve on the air duct is opened, and the butterfly valves on the high-concentration carbon dioxide and oxygen ducts are closed; in the full oxygen mode, the butterfly valve on the air duct is closed, and the butterfly valves on the high-concentration carbon dioxide and oxygen ducts are opened.

2. The air and full oxygen dual-mode grate cooler according to claim 1, characterized in that: The width of the first grate bed and the second grate bed is the same, the first grate bed occupies 30-40% of the designed length of the grate bed, and the second grate bed occupies 60-70% of the designed length of the grate bed.

3. The air and full oxygen dual-mode grate cooler according to claim 1, characterized in that: A crusher is installed at the tail end of the second-stage grate bed.

4. The air and full oxygen dual-mode grate cooler according to claim 1, characterized in that: A material level meter is arranged on the shell body and above the sealing groove.

5. The air and full oxygen dual-mode grate cooler according to claim 1, characterized in that: An ash unloading system is arranged at the bottom of the shell, and a disk conveyor is arranged below the ash unloading system, wherein the ash unloading system comprises an ash unloading hopper arranged at intervals at the bottom of the shell and an ash unloading pipe arranged vertically at the bottom of the ash unloading hopper.

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