CN111170660A - Lime production system and method - Google Patents
Lime production system and method Download PDFInfo
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- CN111170660A CN111170660A CN202010029261.1A CN202010029261A CN111170660A CN 111170660 A CN111170660 A CN 111170660A CN 202010029261 A CN202010029261 A CN 202010029261A CN 111170660 A CN111170660 A CN 111170660A
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2/00—Lime, magnesia or dolomite
- C04B2/10—Preheating, burning calcining or cooling
- C04B2/12—Preheating, burning calcining or cooling in shaft or vertical furnaces
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Abstract
The invention provides a lime production system and method, and belongs to the technical field of lime production. The system comprises a shaft kiln and a heating device, wherein the shaft kiln is sequentially provided with a feeding hole, a preheating section, a reaction section, a cooling section and a discharging hole from top to bottom; the top of the preheating section is connected with a discharge pipeline, the top of the preheating section is connected with the bottom of the cooling section through a cooling pipeline, and the top of the preheating section is also connected with the bottom of the reaction section through a heating pipeline; the heating pipeline is provided with a heating device. After entering the shaft kiln from the feed inlet, the limestone raw material is changed into a lime product after passing through the preheating section, the reaction section and the cooling section in sequence. The system avoids the mixing of carbon dioxide released by limestone decomposition and fuel combustion flue gas, so that the emission carrier gas containing high-concentration carbon dioxide is obtained, carbon dioxide capture can be carried out without gas separation, and the system has an important effect on carbon emission reduction in the lime production process.
Description
Technical Field
The invention relates to the technical field of lime production, in particular to a lime production system and method.
Background
Lime is an important industrial raw material and is widely used in the main industries of ferrous metallurgy, flue gas desulfurization, building, papermaking and the like. Lime is generally obtained by the thermal decomposition of limestone into lime and carbon dioxide in a shaft or rotary kiln, and therefore the carbon emission from the lime production industry is enormous. In china, lime production causes greenhouse gas emissions that increase from 0.35 million tons of equivalent carbon dioxide in 1979 to 1.4 million tons of equivalent carbon dioxide in 2009, where emissions in 2009 account for more than 60% of world emissions. Therefore, as a carbon emission intensive industry, the emission reduction of carbon dioxide in the lime production process is urgent.
The thermal decomposition reaction equation of limestone is as follows:
CaCO3CaO + CO2↑
As can be seen from the above reaction formula, the carbon dioxide in the lime production process comes from two source processes, namely: (1) carbon dioxide released in the limestone decomposition process, generally the mass fraction of carbon dioxide contained in the limestone ore material is about 42%; (2) carbon dioxide released during combustion of the fuel, because the decomposition reaction of limestone is an endothermic reaction, the industry typically provides the high temperature heat required for the thermal decomposition of limestone by combustion of fossil fuels. In the process of the two sources, the carbon emission of the limestone decomposition process is dominant, and accounts for about 70% of the total carbon emission in lime production. For the conventional calcination process widely used for lime production at present, the two parts of carbon dioxide are mixed and then discharged as flue gas. In this way, the flue gas, because of the large content of nitrogen, does not reach the purity required for the transport and storage of carbon dioxide, whereby the capture of carbon dioxide requires a gas separation device and considerable energy consumption for separation. Therefore, the way to separate the two source processes is the development direction of carbon emission reduction in the lime production process.
Recently, CN110451822A proposes a recycling process for recycling and recovering limestone and carbon dioxide from product gas, which has the following main principles: firstly, carrier gas at the top of the shaft kiln is recycled and introduced into a shaft kiln cooling section, the carrier gas is primarily heated by utilizing the waste heat of high-temperature lime products, then the carrier gas is introduced into a heating device for further heating and temperature rise, and finally the carrier gas is introduced into a shaft kiln reaction section to provide heat required by limestone decomposition. The process can realize the capture of carbon dioxide released by limestone decomposition, and has the process characteristics that: and all carrier gas recovered from the top of the shaft kiln is introduced into the cooling section, and is primarily heated by utilizing the waste heat of the high-temperature lime product, and then is completely discharged from the cooling section and introduced into the heating device. However, the scheme of 'preliminary heating the carrier gas by using the waste heat of the high-temperature lime product' proposed by the process has the following defects in the aspect of feasibility: if the carrier gas passes through the cooling section in a pipeline mode, the heat exchange between the carrier gas and the lime particles in the cooling section is the dividing wall type heat exchange, and the problem that the heat exchange pipe needs to work at a high temperature of over 800 ℃ and bears the gravity impact of a limestone particle material layer exists, namely the selection of the heat exchange pipe material is very difficult; if the carrier gas is directly introduced into the cooling section, the heat exchange between the carrier gas and the lime particles in the cooling section is contact heat exchange, and the problem of gas cross exists, namely the carrier gas can continuously and naturally rise to enter the reaction section when reaching the top of the cooling section, and is difficult to enter a heating device outside the shaft kiln.
For this reason, the present invention proposes a carrier gas dual-circuit circulation scheme, which is fundamentally different from the above scheme in that: dividing the carrier gas recovered from the top of the shaft kiln into two parts, introducing one part of the carrier gas serving as cooling carrier gas into a cooling section, carrying out contact type heat exchange on the cooling carrier gas and lime particles, and allowing the carrier gas to naturally rise to enter a reaction section when reaching the top of the cooling section; the other strand is used as heating carrier gas and directly introduced into the heating device. The scheme provided by the invention overcomes the defects of the prior art in the aspect of practicability, and has the characteristic of strong practicability.
Disclosure of Invention
The invention aims to provide a lime production system and method.
The system comprises a shaft kiln and a heating device, wherein the shaft kiln comprises a feeding hole, a preheating section, a reaction section, a cooling section and a discharging hole, and the feeding hole, the preheating section, the reaction section, the cooling section and the discharging hole are sequentially arranged in the shaft kiln from top to bottom; the top of the preheating section is connected with a discharge pipeline, the top of the preheating section is connected with the bottom of the cooling section through a cooling pipeline, and the top of the preheating section is also connected with the bottom of the reaction section through a heating pipeline; a heating device is arranged on the heating pipeline; and a first fan and a second fan are respectively arranged on the cooling pipeline and the heating pipeline.
Wherein the cooling pipeline and the heating pipeline have a section of common pipeline.
The heating device is a hot blast stove.
The shaft kiln is a sleeve kiln.
The bottom of the preheating section is connected with a heating device through a heat return pipeline, and a third fan is arranged on the heat return pipeline.
The method for applying the lime production system specifically comprises the following steps: after entering the shaft kiln from the feeding hole, the limestone raw material is changed into a lime product after passing through the preheating section, the reaction section and the cooling section in sequence, and the lime product is discharged out of the shaft kiln from the discharging hole; the discharged carrier gas is discharged out of the system through a discharge pipeline, the cooling carrier gas is sent to the bottom of the cooling section through a cooling pipeline, and the heating carrier gas is sent to the bottom of the reaction section through a heating pipeline.
And heating carrier gas is heated and heated by a heating device, and the discharge carrier gas, the cooling carrier gas and the heating carrier gas are all from the top of the preheating section.
The exhaust carrier gas, the cooling carrier gas, and the heating carrier gas each include at least one of carbon dioxide and water vapor.
The heat return pipeline is internally communicated with heat return carrier gas, the heat return carrier gas is sent into the heating device through the heat return pipeline, and the heat return carrier gas comes from the bottom of the preheating section.
The technical scheme of the invention has the following beneficial effects:
in the scheme, the mixing of carbon dioxide released by limestone decomposition and fuel combustion flue gas is avoided, so that the emission carrier gas containing high-concentration carbon dioxide is obtained, carbon dioxide capture can be carried out without gas separation, and the method has an important effect on carbon emission reduction in the lime production process. Meanwhile, the carrier gas recovered from the top of the shaft kiln is divided into two parts, one part is used as cooling carrier gas and introduced into the cooling section, and the other part is used as heating carrier gas and directly introduced into the heating device, so that the method has the advantage of strong practicability.
Drawings
FIG. 1 is a first schematic structural diagram of a lime production system of the present invention;
fig. 2 is a schematic structural diagram of a lime production system of the present invention.
Wherein: 1-shaft kiln; 2-a heating device; 3-a discharge conduit; 4-cooling the pipeline; 5-heating the pipeline; 6-heat return pipeline; 10-a feed inlet; 11-a preheating section; 12-a reaction section; 13-a cooling section; 14-a discharge hole; 41-a first fan; 51-a second fan; 61-blower three.
Detailed Description
In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.
The invention provides an ash production system and method.
As shown in figure 1, the system comprises a shaft kiln 1 and a heating device 2, wherein the shaft kiln 1 comprises a feeding hole 10, a preheating section 11, a reaction section 12, a cooling section 13 and a discharging hole 14, and the feeding hole 10, the preheating section 11, the reaction section 12, the cooling section 13 and the discharging hole 14 in the shaft kiln 1 are sequentially arranged from top to bottom; the top of the preheating section 11 is connected with the discharge pipeline 3, the top of the preheating section 11 is connected with the bottom of the cooling section 13 through the cooling pipeline 4, and the top of the preheating section 11 is also connected with the bottom of the reaction section 12 through the heating pipeline 5; the heating pipeline 5 is provided with a heating device 2; the cooling pipeline 4 and the heating pipeline 5 are respectively provided with a first fan 41 and a second fan 51.
As shown in FIG. 2, the system further comprises a heat return pipeline 6, the bottom of the preheating section 11 is connected with the heating device 2 through the heat return pipeline 6, and a third fan 61 is arranged on the heat return pipeline 6.
The following description is given with reference to specific examples.
Example 1
As shown in fig. 1, the production system includes a shaft kiln 1 and a heating device 2. Shaft kiln 1 includes from top to bottom in proper order: a feed inlet 10, a preheating section 11, a reaction section 12, a cooling section 13 and a discharge outlet 14. Wherein, the top of the preheating section 11 is connected with a discharge pipeline 3, the top of the preheating section 11 is connected with the bottom of a cooling section 13 through a cooling pipeline 4, and the top of the preheating section 11 is also connected with the bottom of a reaction section 12 through a heating pipeline 5; the heating pipeline 5 is provided with a heating device 2; the cooling pipeline 4 and the heating pipeline 5 are respectively provided with a first fan 41 and a second fan 51.
The feed inlet 10 is used for adding limestone raw materials into the shaft kiln 1, and the discharge outlet 14 is used for discharging lime products from the shaft kiln 1; the shaft kiln 1 is used for converting limestone into lime, the limestone mass in the preheating section 11 of which is preheated to the initial reaction temperature, the limestone mass in the reaction section 12 of which undergoes a decomposition reaction and releases carbon dioxide gas, and the lime mass in the cooling section 13 of which is cooled.
The discharge pipeline 3 is used for discharging carrier gas in a quantitative mode outwards from the top of the shaft kiln 1 so as to maintain the material balance of the system, and the flow rate of the discharged carrier gas is equal to the flow rate of carbon dioxide released by the decomposition of limestone in the reaction section; the main components of the emission carrier gas are carbon dioxide and water vapor, so that the emission carrier gas can capture the carbon dioxide without a gas separation process, and the emission reduction of the carbon dioxide is facilitated.
The cooling pipeline 4 is used for recovering the carrier gas at the top of the shaft kiln 1 and sending the carrier gas serving as the cooling carrier gas to the bottom of the cooling section 13, and a first fan 41 is arranged on the cooling pipeline 4 to maintain the circulation of the cooling carrier gas.
The heating pipeline 5 is used for recovering the carrier gas at the top of the shaft kiln 1 and sending the carrier gas serving as the heating carrier gas to the bottom of the reaction section 12, a second fan 51 is arranged on the heating pipeline 5 to maintain the circulation of the heating carrier gas, and a heating device 2 is further arranged on the heating pipeline 5 to improve the temperature of the heating carrier gas; the heating carrier gas is typically heated to a temperature above 1200 c and then introduced to the bottom of the reaction section 12 to provide the heat required for the limestone decomposition reaction.
The heating device 2 is typically a hot blast stove, such as a top-fired stove, a kalukin stove or the like.
The shaft kiln 1 is typically a sleeve kiln.
Example 2
The specific process mainly comprises the following steps:
limestone raw materials enter the shaft kiln 1 from a feeding hole 10, in the shaft kiln, a slowly descending material block passes through a preheating section 11, a reaction section 12 and a cooling section 13 in sequence, the material block is in contact with ascending carrier gas to transfer heat and mass, limestone in the material block is converted into lime, and a lime product is obtained and discharged out of the shaft kiln 1 from a discharging hole 14.
The ascending carrier gas is discharged after reaching the top of the preheating section 11 in three portions: discharge carrier gas, cool carrier gas, and heat carrier gas. Wherein:
the exhaust carrier gas exits the system through exhaust line 3 to maintain the material balance of the system.
The cooling carrier gas is fed to the bottom of the cooling section 13 through the cooling duct 4. In the cooling section 13, the cooling carrier gas flowing upward cools the material block and simultaneously the temperature of the material block is increased, and the cooling carrier gas naturally rises into the bottom of the reaction section 12 after reaching the top of the cooling section 13.
The heating carrier gas is sent to the bottom of the reaction section 12 through the heating pipeline 5, and the heating carrier gas is heated and heated through the heating device 2. In the reaction section 12, the heating carrier gas and the cooling carrier gas from the bottom of the reaction section 12 are mixed into the carrier gas, the rising flowing carrier gas transfers heat to the material block, the temperature of the rising flowing carrier gas is gradually reduced, limestone in the material block is continuously decomposed into lime and carbon dioxide after the material block absorbs heat, therefore, the mass flow of the carrier gas is gradually increased, and the carrier gas naturally rises to the bottom of the preheating section 11 after reaching the top of the reaction section 12. In the preheating section 11, the carrier gas flowing upward transfers heat to the mass block, the temperature of the mass block is gradually reduced, but the mass block does not reach the initial decomposition temperature, so that the mass flow of the carrier gas is basically kept unchanged, and the carrier gas is divided into three parts to be discharged when reaching the top of the preheating section 11, thereby completing the circulation of the carrier gas.
The main component of the exhaust carrier gas, the cooling carrier gas and the heating carrier gas is carbon dioxide, and a certain amount of water vapor is also contained.
Example 3
As shown in FIG. 2, in the system of the present invention, the bottom of the preheating section 11 of the shaft kiln 1 can be further connected to the heating device 2 through a heat recovery pipeline 6, and a third fan 61 is arranged on the heat recovery pipeline 6.
Example 4
Compared to example 2, the process of the lime production system as shown in fig. 2 also feeds recuperative carrier gas to the heating device 2 via recuperative piping 6, said recuperative carrier gas coming from the bottom of the preheating section 11.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (9)
1. A lime production system which characterized in that: the device comprises a shaft kiln (1) and a heating device (2), wherein the shaft kiln (1) comprises a feed inlet (10), a preheating section (11), a reaction section (12), a cooling section (13) and a discharge outlet (14), and the feed inlet (10), the preheating section (11), the reaction section (12), the cooling section (13) and the discharge outlet (14) are sequentially arranged from top to bottom in the shaft kiln (1); the top of the preheating section (11) is connected with a discharge pipeline (3), the top of the preheating section (11) is connected with the bottom of a cooling section (13) through a cooling pipeline (4), and the top of the preheating section (11) is also connected with the bottom of a reaction section (12) through a heating pipeline (5); the heating pipeline (5) is provided with a heating device (2); the cooling pipeline (4) and the heating pipeline (5) are respectively provided with a first fan (41) and a second fan (51).
2. The lime production system of claim 1, wherein: the cooling pipeline (4) and the heating pipeline (5) are provided with a section of common pipeline.
3. The lime production system of claim 1, wherein: the heating device (2) is a hot blast stove.
4. The lime production system of claim 1, wherein: the shaft kiln (1) is a sleeve kiln.
5. The lime production system of claim 1, wherein: the bottom of the preheating section (11) is connected with the heating device (2) through a heat return pipeline (6), and a third fan (61) is arranged on the heat return pipeline (6).
6. A method of using the lime production system of claim 1, wherein: limestone raw materials enter the shaft kiln (1) from the feeding hole (10), then are changed into lime products after passing through the preheating section (11), the reaction section (12) and the cooling section (13) in sequence, and the lime products are discharged out of the shaft kiln (1) from the discharging hole (14); the discharged carrier gas is discharged out of the system through a discharge pipeline (3), the cooling carrier gas is sent to the bottom of a cooling section (13) through a cooling pipeline (4), and the heating carrier gas is sent to the bottom of a reaction section (12) through a heating pipeline (5).
7. The method of using the lime production system of claim 6, wherein: the heating carrier gas is heated and heated by a heating device (2), and the discharge carrier gas, the cooling carrier gas and the heating carrier gas are all from the top of the preheating section (11).
8. The method of using the lime production system of claim 6, wherein: the exhaust carrier gas, the cooling carrier gas, and the heating carrier gas each include at least one of carbon dioxide and water vapor.
9. The lime production system of claim 5, wherein: the heat recovery carrier gas is introduced into the heat recovery pipeline (6), the heat recovery carrier gas is sent into the heating device (2) through the heat recovery pipeline (6), and the heat recovery carrier gas comes from the bottom of the preheating section (11).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010029261.1A CN111170660A (en) | 2020-01-10 | 2020-01-10 | Lime production system and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010029261.1A CN111170660A (en) | 2020-01-10 | 2020-01-10 | Lime production system and method |
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| Publication Number | Publication Date |
|---|---|
| CN111170660A true CN111170660A (en) | 2020-05-19 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202010029261.1A Pending CN111170660A (en) | 2020-01-10 | 2020-01-10 | Lime production system and method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111763019A (en) * | 2020-07-27 | 2020-10-13 | 北京科技大学 | Carbon capture lime calcining system and application method |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5460296A (en) * | 1977-10-21 | 1979-05-15 | Tatsu Chisaki | Top type lime burining furnace |
| CN108314336A (en) * | 2018-05-09 | 2018-07-24 | 王长春 | A kind of lime kiln device using circulating air |
| CN110423023A (en) * | 2019-09-04 | 2019-11-08 | 石家庄圣宏达热能工程技术股份有限公司 | Carbon-lime kiln coal gas system is not arranged |
| CN110451822A (en) * | 2019-08-15 | 2019-11-15 | 北京科技大学 | A kind of product gas Cyclic Calcination lime stone and Resources of Carbon Dioxide recovery process |
-
2020
- 2020-01-10 CN CN202010029261.1A patent/CN111170660A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5460296A (en) * | 1977-10-21 | 1979-05-15 | Tatsu Chisaki | Top type lime burining furnace |
| CN108314336A (en) * | 2018-05-09 | 2018-07-24 | 王长春 | A kind of lime kiln device using circulating air |
| CN110451822A (en) * | 2019-08-15 | 2019-11-15 | 北京科技大学 | A kind of product gas Cyclic Calcination lime stone and Resources of Carbon Dioxide recovery process |
| CN110423023A (en) * | 2019-09-04 | 2019-11-08 | 石家庄圣宏达热能工程技术股份有限公司 | Carbon-lime kiln coal gas system is not arranged |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111763019A (en) * | 2020-07-27 | 2020-10-13 | 北京科技大学 | Carbon capture lime calcining system and application method |
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Application publication date: 20200519 |