CN117213227A - Method and system for obtaining high-concentration carbon dioxide flue gas based on calcined cement clinker - Google Patents
Method and system for obtaining high-concentration carbon dioxide flue gas based on calcined cement clinker Download PDFInfo
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- CN117213227A CN117213227A CN202311194724.XA CN202311194724A CN117213227A CN 117213227 A CN117213227 A CN 117213227A CN 202311194724 A CN202311194724 A CN 202311194724A CN 117213227 A CN117213227 A CN 117213227A
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- carbon dioxide
- heat exchange
- flue gas
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- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 title claims abstract description 248
- 229910002092 carbon dioxide Inorganic materials 0.000 title claims abstract description 124
- 239000001569 carbon dioxide Substances 0.000 title claims abstract description 124
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 81
- 239000003546 flue gas Substances 0.000 title claims abstract description 81
- 238000000034 method Methods 0.000 title claims abstract description 49
- 239000004568 cement Substances 0.000 title claims abstract description 19
- 239000007789 gas Substances 0.000 claims abstract description 58
- 235000012054 meals Nutrition 0.000 claims abstract description 55
- 239000000779 smoke Substances 0.000 claims abstract description 44
- 238000001354 calcination Methods 0.000 claims abstract description 21
- 238000001816 cooling Methods 0.000 claims abstract description 19
- 230000005674 electromagnetic induction Effects 0.000 claims abstract description 14
- 238000007599 discharging Methods 0.000 claims abstract description 9
- 239000002994 raw material Substances 0.000 claims description 34
- 239000000463 material Substances 0.000 claims description 18
- 230000007423 decrease Effects 0.000 claims description 16
- JTJMJGYZQZDUJJ-UHFFFAOYSA-N phencyclidine Chemical class C1CCCCN1C1(C=2C=CC=CC=2)CCCCC1 JTJMJGYZQZDUJJ-UHFFFAOYSA-N 0.000 claims description 14
- 239000002918 waste heat Substances 0.000 claims description 10
- 238000000354 decomposition reaction Methods 0.000 claims description 7
- 239000000428 dust Substances 0.000 claims description 7
- 230000001276 controlling effect Effects 0.000 abstract description 12
- 238000010438 heat treatment Methods 0.000 abstract description 4
- 230000001105 regulatory effect Effects 0.000 abstract description 3
- 239000000446 fuel Substances 0.000 description 5
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 4
- 238000002485 combustion reaction Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000000112 cooling gas Substances 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 230000009919 sequestration Effects 0.000 description 2
- 230000000391 smoking effect Effects 0.000 description 2
- 238000003746 solid phase reaction Methods 0.000 description 2
- 239000002912 waste gas Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 239000003517 fume Substances 0.000 description 1
- 238000004868 gas analysis Methods 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
Abstract
The application provides a method and a system for obtaining high-concentration carbon dioxide flue gas based on calcined cement clinker, wherein the system comprises: the rotary kiln is provided with a smoke chamber and a kiln head cover, and surrounds the electromagnetic induction device along the length direction; a pressure sensor and a gas analyzer are arranged in the kiln head cover; the air cooling device is used for heating clinker generated by calcining the raw meal by using the air cooling rotary kiln through the electromagnetic induction device; the first heat exchange device is used for exchanging heat between the raw meal and smoke generated by calcining the raw meal in the rotary kiln; the second heat exchange device is used for exchanging heat between the raw meal and the air subjected to heat exchange; the flue gas pipeline is provided with a first fan for discharging the flue gas subjected to heat exchange; the air pipeline is provided with a second fan for discharging the air subjected to the secondary heat exchange; the control device is used for regulating and controlling the rotating speeds of the first fan and the second fan, so that the carbon dioxide concentration is reduced to a threshold value and the pressure value is reduced to be within a preset range value. According to the system provided by the application, high-concentration carbon dioxide flue gas can be obtained.
Description
Technical Field
The application relates to the technical field of cement calcination, in particular to a method and a system for obtaining high-concentration carbon dioxide smoke based on calcined cement clinker.
Background
The carbon dioxide capture system is used to remove carbon dioxide from the gas stream or to separate carbon dioxide as a gaseous product. Capture is the first step in carbon capture and sequestration (carbon capture and storage, CCS technology for short). Carbon dioxide is required to be present in higher purity for transportation and sequestration, and in most cases the concentration of carbon dioxide in industrial tail gas is not as high as this requirement, so carbon dioxide must be separated from the tail gas, a process known as carbon dioxide capture. The carbon dioxide capturing system can be divided into a plurality of categories such as chemical absorption, physical absorption, membrane separation, cryogenic separation and the like, and the capturing mode and equipment selection are required to be carried out according to the actual characteristics, parameters and the like of a carbon dioxide emission source during application.
In the process of implementing the present application, the inventor finds that at least the following problems exist in the prior art:
the conventional rotary kiln cement calcination process needs fuel combustion, the combustion-supporting medium is air, and the concentration of carbon dioxide in the finally produced flue gas is low, generally between 18 and 25 percent. The investment and the operation cost of the carbon dioxide capturing system are greatly related to the carbon dioxide concentration, and the investment and the operation cost of the carbon dioxide capturing system are greatly increased by the low-concentration carbon dioxide flue gas generated by the conventional rotary kiln cement calcination process.
There is therefore a need for a method and a system for obtaining high concentration carbon dioxide fumes based on calcining cement clinker, to at least partially solve the above-mentioned technical problems.
Disclosure of Invention
The embodiment of the application provides a method and a system for obtaining high-concentration carbon dioxide flue gas based on calcined cement clinker, which can obtain high-concentration carbon dioxide flue gas and have low energy consumption.
In a first aspect, the present application provides a system for obtaining high concentration carbon dioxide flue gas based on calcining cement clinker, comprising: the tail part and the head part of the rotary kiln are respectively provided with a smoke chamber and a kiln head cover, and the rotary kiln surrounds the electromagnetic induction device along the length direction; a pressure sensor and a gas analyzer are arranged in the kiln head cover;
the kiln head cover is provided with a hot air pipeline for guiding out air after heat exchange;
the first heat exchange device is communicated to the smoke chamber and is used for exchanging heat between the raw meal and smoke generated by calcining the raw meal in the rotary kiln, and comprises a first raw meal inlet for introducing the raw meal and a first raw meal outlet for leading out the raw meal subjected to heat exchange to the smoke chamber;
the second heat exchange device is respectively communicated with the smoke chamber and the hot air pipeline and is used for exchanging heat between the raw meal and the air subjected to heat exchange, and comprises a second raw meal inlet for introducing the raw meal and a second raw meal outlet for leading out the raw meal subjected to heat exchange to the smoke chamber;
the flue gas pipeline is communicated with the first heat exchange device, is provided with a first fan and is used for discharging the flue gas subjected to heat exchange;
the air pipeline is communicated with the second heat exchange device, is provided with a second fan and is used for discharging air subjected to secondary heat exchange;
control device, control device is connected respectively to pressure sensor, gas analyzer, first fan and second fan, control device is used for: when the carbon dioxide concentration monitored by the gas analyzer is greater than a threshold value, controlling the rotating speed of the first fan to be gradually increased until the rotating speed is remained when the carbon dioxide concentration can be reduced to the threshold value, wherein the pressure value monitored by the pressure sensor is within a preset range value; if the pressure value monitored by the pressure sensor is larger than the upper limit of the preset range value in the process of controlling the rotating speed of the first fan to be gradually increased, controlling the rotating speed of the second fan to be gradually reduced, wherein the rotating speed of the first fan is unchanged until the rotating speeds of the first fan and the second fan stay at the rotating speeds when the carbon dioxide concentration can be reduced to the threshold value and the pressure value is reduced to the preset range value; if the carbon dioxide concentration is not reduced to the threshold value in the process of controlling the rotation speed of the second fan to gradually decrease, controlling the rotation speed of the first fan to continuously gradually increase, wherein the rotation speed of the second fan is unchanged; and repeating the process until the first fan and the second fan stay at the rotating speeds when the concentration of the carbon dioxide can be reduced to the threshold value and the pressure value is reduced to the preset range value.
According to the system disclosed by the application, the raw materials in the rotary kiln are heated and calcined through the electromagnetic induction device, and the raw materials are decomposed to release carbon dioxide gas, so that compared with the traditional fuel combustion mode, the system does not bring air, and the concentration of carbon dioxide in the generated carbon dioxide flue gas is high; simultaneously, the rotating speeds of the first fan and the second fan are regulated and controlled by the control device, and the concentration of carbon dioxide is controlled to be reduced to a threshold value and the pressure value to be reduced to be within a preset range value, so that the carbon dioxide flue gas and the air subjected to heat exchange are respectively self-propelled in respective paths and are not mixed, and the high concentration of carbon dioxide is further ensured; in addition, the whole system utilizes air to cool down clinker, and utilizes carbon dioxide flue gas and heat exchanged air to preheat raw materials, so that the energy is reused, and the energy consumption is low.
Optionally, the first heat exchange device comprises a plurality of cyclones arranged from top to bottom, a bottom material outlet of the cyclone positioned at the lowest is communicated with the smoke chamber, a gas inlet of the cyclone positioned at the lowest is communicated with the smoke chamber, and a top gas outlet of the cyclone positioned at the highest is communicated with the smoke pipeline; the gas outlet of the cyclone cylinder positioned below is communicated with the cyclone cylinder positioned above through a connecting pipeline, and the material outlet at the bottom of the cyclone cylinder positioned above is communicated with the connecting pipeline below;
wherein raw meal is fed into the connecting pipe located uppermost.
Optionally, the second heat exchange device also comprises a plurality of cyclones arranged from top to bottom, a bottom material outlet of the cyclone positioned at the lowest is communicated with the smoke chamber, a gas inlet of the cyclone positioned at the lowest is communicated with the hot air pipeline, and a top gas outlet of the cyclone positioned at the highest is communicated with the air pipeline; the gas outlet of the cyclone cylinder positioned below is communicated with the cyclone cylinder positioned above through a connecting pipeline, and the material outlet at the bottom of the cyclone cylinder positioned above is communicated with the connecting pipeline below;
wherein raw meal is fed into the connecting pipe located uppermost.
Optionally, the air cooling device comprises a grate cooler, and a blower for introducing air is arranged at the bottom of the grate cooler.
Optionally, the ratio of raw materials fed into the first heat exchange device and the second heat exchange device is 1:2-5.
Optionally, the flue gas discharged by the flue gas pipeline is further processed by a dust collector, and the processed flue gas can be communicated to a carbon dioxide capturing system.
Optionally, the flue gas duct and/or the air duct is also connected to a waste heat boiler.
In a second aspect, the application also provides a method for obtaining high-concentration carbon dioxide flue gas based on calcining cement clinker, and a system based on the technical scheme, which specifically comprises the following steps:
the raw materials are heated and decomposed in a rotary kiln provided with an electromagnetic induction device to generate carbon dioxide gas, and are calcined into clinker;
flue gas containing carbon dioxide gas generated by decomposition enters a first heat exchange device through a flue gas chamber, clinker enters an air cooling device through a kiln hood to exchange heat with air for cooling, and the air after heat exchange enters a second heat exchange device;
before entering the rotary kiln, the raw materials are respectively put into a first heat exchange device and a second heat exchange device to exchange heat with smoke and air, and enter the rotary kiln through a smoke chamber to be calcined after heat exchange, and the smoke and air after heat exchange are respectively discharged through a smoke pipeline and an air pipeline; the flue gas exhausted by the flue gas pipeline is high-concentration carbon dioxide flue gas, and the concentration of carbon dioxide in the flue gas is more than 80%;
when the carbon dioxide concentration monitored by the gas analyzer is greater than a threshold value, the first fan gradually increases the rotating speed until the rotating speed stays at the rotating speed when the carbon dioxide concentration is reduced to the threshold value, and the pressure value monitored by the pressure sensor is always within a preset range value; in the process, if the pressure value monitored by the pressure sensor is larger than the upper limit of the preset range value but the carbon dioxide concentration does not decrease to the threshold value in the process of gradually increasing the rotating speed, the second fan starts to gradually decrease the rotating speed, and the rotating speed of the first fan is kept unchanged until the first fan and the second fan respectively stay at the rotating speeds when the carbon dioxide concentration decreases to the threshold value and the pressure value decreases to the preset range value; in the above process, if the carbon dioxide concentration of the second fan is not reduced to the threshold value when the pressure value is smaller than the lower limit of the preset range value in the process of gradually reducing the rotating speed, the first fan continues to gradually increase the rotating speed, and the rotating speed of the second fan is kept unchanged; repeating the steps until the first fan and the second fan stay at the rotating speeds when the carbon dioxide concentration is reduced to the threshold value and the pressure value is reduced to the preset range value.
The application has the advantages that by utilizing the technical scheme according to the embodiment of the application, the application has at least the following advantages:
1. the raw materials in the rotary kiln are heated and calcined through the electromagnetic induction device, and the raw materials are decomposed to release carbon dioxide gas, so that compared with the traditional fuel combustion mode, no air is taken in, no flue gas generated by fuel combustion exists, the amount of waste gas is greatly reduced, and the concentration of carbon dioxide in the generated carbon dioxide flue gas is high;
2. through controlling means, pressure sensor and the gas analysis appearance that set up, regulate and control the rotational speed of first fan and second fan through controlling means, control carbon dioxide concentration falls to threshold value and pressure value and falls to the within range value that presets, aim at make the interior raw meal of rotary kiln decompose the carbon dioxide gas of release, with the air after the heat transfer not mix, further ensure the high concentration of carbon dioxide.
Additional advantages, objects, and features of the application will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the application. The objectives and other advantages of the application may be realized and attained by the structure particularly pointed out in the written description and drawings.
It will be appreciated by those skilled in the art that the objects and advantages that can be achieved with the present application are not limited to the above-described specific ones, and that the above and other objects that can be achieved with the present application will be more clearly understood from the following detailed description.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate and together with the description serve to explain the application. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the application. Corresponding parts in the drawings may be exaggerated, i.e. made larger relative to other parts in an exemplary device actually manufactured according to the present application, for convenience in showing and describing some parts of the present application. In the drawings:
FIG. 1 is an overall schematic of a system for obtaining high concentration carbon dioxide flue gas based on calcining cement clinker in accordance with an embodiment of the present application; and
fig. 2 is a schematic diagram showing connection between a control device and a pressure sensor, a gas analyzer, a first fan and a second fan, respectively, in a system for obtaining high-concentration carbon dioxide flue gas based on calcining cement clinker according to an embodiment of the present application.
Reference numerals illustrate:
100. a system;
110. a rotary kiln; 111. a smoke chamber; 112. a kiln head cover; 113. an electromagnetic induction device; 114. a pressure sensor; 115. a gas analyzer;
120. a grate cooler; 121. a blower; 122. a hot air duct;
130. a first heat exchange device;
140. a second heat exchange device;
150. a flue gas duct; 151. A first fan;
160. an air duct; 161. A second fan;
170. a control device;
180. a cyclone; 181. a connecting pipe;
190. a waste heat boiler; 191. a dust collector; 192. a carbon dioxide capture system.
Detailed Description
The objects and functions of the present application and methods for achieving these objects and functions will be elucidated by referring to exemplary embodiments. However, the present application is not limited to the exemplary embodiments disclosed below; this may be implemented in different forms. The essence of the description is merely to aid one skilled in the relevant art in comprehensively understanding the specific details of the application.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present application. As used herein, the singular is intended to include the plural unless the context clearly indicates otherwise. Furthermore, it will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Ordinal numbers such as "first" and "second" cited in the present application are merely identifiers and do not have any other meaning, such as a particular order or the like. Also, for example, the term "first component" does not itself connote the presence of "second component" and the term "second component" does not itself connote the presence of "first component".
It should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", and the like are used herein for illustrative purposes only and are not limiting.
In a first aspect, the present application provides a system 100 for obtaining high-concentration carbon dioxide flue gas based on calcining cement clinker, which is applied to the technical field of cement calcination and solves the problem of low concentration of carbon dioxide in flue gas generated by the existing cement calcination process.
As shown in fig. 1 and 2, in a preferred embodiment, the system 100 includes a rotary kiln 110, an air cooling device, a first heat exchange device 130, a second heat exchange device 140, a flue gas duct 150, an air duct 160, and a control device 170. The rotary kiln 110 is used for heating the calcined raw meal. The wind cooling device is used for cooling clinker generated by calcining raw materials. The first heat exchanging device 130 is used for preheating the raw meal utilization flue gas fed into the rotary kiln 110. The second heat exchange device 140 is used for preheating raw meal fed into the rotary kiln 110 by using air. The flue gas pipe 150 is used for discharging flue gas generated by the rotary kiln 110 to obtain high-concentration carbon dioxide flue gas. The air duct 160 is used to discharge the heat exchanged air. The control device 170 is used for controlling the pressure balance in the kiln head cover 112, so that the carbon dioxide flue gas generated in the rotary kiln 110 is not mixed with the air passing through the kiln head cover 112, and the high concentration of the carbon dioxide in the flue gas is ensured.
Specifically, the rotary kiln 110 is provided with a smoke chamber 111 and a kiln head hood 112 at the tail and head, respectively. Raw meal enters the rotary kiln 110 through the flue box 111. Smoke passing through smoke chamber111 are discharged outwards. The clinker is directed outwardly through the kiln hood 112. The rotary kiln 110 is a rotatable cylinder structure. The rotary kiln 110 can include an intake section, a firing section, and a cooling section. The rotary kiln 110 is surrounded by an electromagnetic induction device 113, such as an electromagnetic induction coil, in the longitudinal direction. The high-frequency alternating current generates an alternating magnetic field through the coil, so that the rotary kiln 110 generates eddy current self-heating. The raw material in the rotary kiln 110 is heated to realize carbonate decomposition, and the decomposition product CaO of the raw material in the advancing process and SiO in the raw material 2 、Fe 2 O 3 、Al 2 O 3 And the like, and mutually diffusing to carry out solid phase reaction to form clinker minerals. During this process the carbonate decomposes to produce carbon dioxide.
A pressure sensor 114 and a gas analyzer 115 are disposed within the kiln hood 112. The pressure sensor 114 is used to monitor pressure data within the kiln hood 112 in real time. The gas analyzer 115 is used to monitor the carbon dioxide concentration in the kiln head hood 112 in real time, and to monitor whether the carbon dioxide concentration exceeds the normal carbon dioxide content in the air (the carbon dioxide content in the air is 0.03%) so as to know whether the flue gas is mixed in the air in the kiln head hood 112.
The wind cooling means communicates to the kiln hood 112. The air cooling device is used to cool the clinker produced by calcining the raw meal by air in the rotary kiln 110 via the electromagnetic induction device 113. The kiln head hood 112 is provided with hot air ducts 122 for leading out heat exchanged air. The air cooling device may be a prior art device. For example, the air cooling device may employ the grate cooler 120. The bottom of the grate cooler 120 may be provided with a blower 121 for introducing air. The cooling gas in this embodiment is air, but other cooling gases may be used, and the gas object monitored by the gas analyzer 115 is adapted accordingly.
The first heat exchanging arrangement 130 communicates to the smoking chamber 111. The first heat exchanging device 130 is used for exchanging heat between the raw meal and flue gas generated by calcining the raw meal in the rotary kiln 110. The first heat exchange device 130 comprises a first raw material inlet for introducing raw material and a first raw material outlet for leading heat exchanged raw material out to the smoking chamber 111. Wherein the first heat exchanging arrangement 130 may be a prior art arrangement.
The second heat exchanging device 140 is respectively communicated to the smoke chamber 111 and the hot air duct 122. The second heat exchange device 140 is used for exchanging heat between the raw meal and the air after heat exchange. The second heat exchange means 140 comprises a second raw meal inlet for introducing raw meal and a second raw meal outlet for leading out the heat exchanged raw meal to the flue box 111. Wherein the second heat exchange device 140 may be a prior art device.
The flue gas duct 150 communicates to the first heat exchange device 130. The flue gas pipeline 150 is provided with a first fan 151 for discharging the flue gas after heat exchange. The first fan 151 normally operates at a certain rotational speed.
The air duct 160 communicates to the second heat exchanging arrangement 140. The air duct 160 is provided with a second fan 161 for discharging the air after the secondary heat exchange. The second fan 161 normally operates at a certain rotational speed.
The control device 170 is connected to the pressure sensor 114, the gas analyzer 115, the first blower 151, and the second blower 161, respectively. When the carbon dioxide concentration monitored by the gas analyzer 115 is greater than the threshold value (i.e., the carbon dioxide content in the air is 0.03%), the control device 170 controls the rotational speed of the first fan 151 to be gradually increased until the rotational speed at which the carbon dioxide concentration is reduced to the threshold value is remained, during which the pressure value monitored by the pressure sensor 114 is within a preset range of values, for example, between minus 10Pa and minus 35 Pa. In the above process, if the pressure value monitored by the pressure sensor 114 is greater than the upper limit of the preset range value (i.e., minus 35 Pa) during the process of controlling the rotation speed of the first fan 151 to gradually increase, the control device 170 controls the rotation speed of the second fan 161 to gradually decrease, and at this time, the rotation speed of the first fan 151 is unchanged (i.e., the rotation speed when the rotation speed of the second fan 161 is kept to be adjusted), until the first fan 151 and the second fan 161 stay at the rotation speeds when the carbon dioxide concentration is reduced to the threshold value and the pressure value is reduced to the preset range value. If the carbon dioxide concentration is not reduced to the threshold value while controlling the rotation speed of the second fan 161 to gradually decrease, the control device 170 controls the rotation speed of the first fan 151 to continuously gradually increase, and at this time, the rotation speed of the second fan 161 is unchanged (i.e. the rotation speed when the rotation speed of the first fan 151 starts to be adjusted is maintained). The above process is repeated until the first fan 151 and the second fan 161 stay at the rotational speeds at which the carbon dioxide concentration falls within the threshold value and the pressure value falls within the preset range value.
In the above process, the control device 170 combines the adjustment made by the pressure sensor 114, the gas analyzer 115, the first fan 151 and the second fan 161 to realize that the pressure balance point in the rotary kiln 110 is located at the kiln outlet end (near the kiln hood 112), so that the carbon dioxide gas generated by the thermal decomposition of the raw materials in the rotary kiln 110 is discharged only through the rotary kiln 110, the smoke chamber 111 and the first heat exchange device 130, and the air exchanging heat with the clinker is discharged only through the hot air pipeline 122 and the second heat exchange device 140 after passing through the kiln hood 112, and the two are not mixed, thereby ensuring the high concentration of carbon dioxide in the flue gas.
According to the system 100 of the application, the raw materials in the rotary kiln 110 are heated and calcined through the electromagnetic induction device 113, and the raw materials are decomposed to release carbon dioxide gas, so that compared with the traditional method of burning fuel, the system does not take in air, and the concentration of carbon dioxide in the generated carbon dioxide flue gas is high; simultaneously, the rotating speeds of the first fan 151 and the second fan 161 are regulated and controlled by the control device 170, and the concentration of carbon dioxide is controlled to be reduced to a threshold value and the pressure value is controlled to be reduced to be within a preset range value, so that the carbon dioxide flue gas and the air subjected to heat exchange are respectively self-propelled in respective paths and are not mixed, and the high concentration of carbon dioxide is further ensured; in addition, the whole system 100 utilizes air to cool down clinker, utilizes carbon dioxide flue gas and heat exchanged air to preheat raw materials, and has the advantages of energy reuse and low energy consumption.
Referring to fig. 1, in order to provide a first heat exchanging apparatus 130 with good heat exchanging effect, the first heat exchanging apparatus 130 may include a plurality of cyclones 180 arranged from top to bottom. The number of the cyclones 180 is not limited, and may be 5, 6 or other numbers, for example. Wherein the bottom material outlet of the cyclone 180 located at the lowest position is communicated to the smoke chamber 111. The gas inlet of the lowermost cyclone 180 communicates with the smoke chamber 111. The top gas outlet of the uppermost cyclone 180 is connected to the flue gas duct 150. The gas outlet of the cyclone 180 located below is communicated to the cyclone 180 located above through a connecting pipe 181. The bottom material outlet of the cyclone 180 positioned above is communicated to the connecting pipeline 181 positioned below. Wherein raw meal is fed into the uppermost connecting pipe 181.
With continued reference to fig. 1, also to provide a second heat exchange device 140 with good heat exchange effect, the second heat exchange device 140 may also include a plurality of cyclones 180 arranged from top to bottom. The number of the cyclones 180 is not limited, and may be 5, 6 or other numbers, for example. The bottom material outlet of the cyclone 180 located at the lowest position is communicated to the smoke chamber 111. The gas inlet of the lowermost cyclone 180 is connected to the hot air duct 122. The top gas outlet of the uppermost cyclone 180 is connected to the air duct 160. Wherein, the gas outlet of the cyclone cylinder 180 positioned below is communicated with the cyclone cylinder 180 positioned above through a connecting pipeline 181. The bottom material outlet of the cyclone 180 positioned above is communicated to the connecting pipeline 181 positioned below. Wherein raw meal is fed into the uppermost connecting pipe 181.
In order to ensure that the first heat exchange device 130 and the second heat exchange device 140 have basically the same feed gas ratio, the raw materials of the first heat exchange device 130 and the second heat exchange device 140 are added in the ratio of 1:2-5. For example, the first heat exchange device 130 feeds about 1/4 of the raw meal and the second heat exchange device 140 feeds about 3/4 of the raw meal.
In a preferred embodiment, the flue gas exiting the flue gas duct 150 may also be subjected to a dust removal process via a dust collector 191. The dedusted flue gas may be communicated to a carbon dioxide capture system 192 for use by the carbon dioxide capture system 192.
Further, the flue gas duct 150 and the air duct 160 may also be connected to a waste heat boiler 190 for waste heat utilization.
The operation of the system 100 will be described below with reference to fig. 1, taking the example that the first heat exchanging device 130 and the second heat exchanging device 140 are each provided with 6 cyclones 180:
raw meal is fed from the connection pipe 181 between the cyclone C2A and C1-A1, C1-A2 of the first heat exchange means 130, and the connection pipe 181 between C2B and C1-B1, C1-B2, the connection pipe 181 between C2A and C1-A1, C1-A2 being fed with about 1/4 raw meal, the connection pipe 181 between C2B and C1-B1, C1-B2 being fed with 3/4 raw meal. Raw materials are dispersed in the connecting pipeline 181, heat exchange is carried out, the raw materials enter the C1-A1, C1-A2, C1-B1 and C1-B2 cyclone along with air flow, the raw materials are separated in the cyclone 180, the air is discharged from the top of the cyclone 180, the C1-A1 and C1-A2 cyclone discharge high-concentration carbon dioxide flue gas, and the C1-B1 and C1-B2 cyclone discharge hot air. The raw meal is collected in the cone of cyclone 180 and discharged.
A connecting pipeline 181 between C2A and C3A for feeding the raw materials discharged from the cone parts of the C1-A1 and C1-A2 cyclones; raw materials discharged from the cone parts of the C1-B1 and C1-B2 cyclones are fed into a connecting pipeline 181 between the C2B and the C3B. Raw materials disperse in connecting pipe 181, heat transfer, along with the air current entering C2A, C B cyclone, the material gas carries out the material gas separation in cyclone 180, and gas is discharged from the top of cyclone 180, and the C2A cyclone discharge is high-concentration carbon dioxide flue gas, and the C2B cyclone discharge is the hot air. Raw meal is collected into the cone of the C2A, C2B cyclone and discharged. And materials are analogically processed through C3A, C B, C4A, C B, C5A, C5B and C6A, C6B cyclones, and heated raw materials are finally discharged from the cone part of the C6A, C6B cyclone and fed into the smoke chamber 111.
The heated raw meal is fed into the smoke chamber 111 and then enters the rotary kiln 110, and the high-frequency alternating current generates an alternating magnetic field through a coil, so that the rotary kiln 110 generates vortex self-heating. The raw materials in the kiln are heated to realize carbonate decomposition, and decomposition products CaO of the materials in the advancing process and SiO in raw materials 2 、Fe 2 O 3 、Al 2 O 3 And the like, and mutually diffusing to carry out solid phase reaction to form clinker minerals. The materials pass through the kiln, and the clinker calcination process is completed. Carbon dioxide gas generated by decomposing carbonate in the process is conveyed from the kiln interior and the kiln tail smoke chamber 111 to the inlet of the cyclone cylinder C6A.
The calcined clinker is fed into the front section of the grate cooler 120, the clinker moves continuously from an inlet to an outlet on the grate cooler 120 and exchanges heat with air entering by a blower 121 at the bottom of the grate cooler 120, cooling of the clinker and recovery of heat are completed, and 700-850 ℃ high-temperature air enters the inlet of the cyclone C6B through a kiln hood 112 and a hot air pipeline 122. By controlling the rotational speed of the high temperature first fan 151 and the second fan 161, a pressure balance point in the kiln is achievedAt the kiln exit end (near the kiln hood 112) to effect decomposition of CO within the kiln 2 Only the kiln 110 is moved into the kiln tail smoke chamber 111, and the high-temperature air only enters the hot air pipeline 122 through the kiln head cover 112, so that the two gases respectively move along the respective paths without mixing.
Excess preheating at the tail of the grate cooler 120 is removed from the tail and can enter the waste heat boiler 190 or be used for drying materials and the like.
The high-concentration carbon dioxide flue gas subjected to heat exchange from the outlets of the cyclones C1-A1 and C1-A2 enters the waste heat boiler 190 for waste heat utilization, then enters the high-temperature first fan 151 and the dust collector 191, and is fed into the carbon dioxide capturing system 192 for further carbon dioxide purification. The hot air subjected to heat exchange from the outlets of the cyclones C1-B1 and C1-B2 is subjected to waste heat utilization by the waste heat boiler 190, then enters the high-temperature second fan 161, is fed into a raw material drying and waste gas treatment system, and is discharged from a chimney after dust removal.
In a second aspect, the present application also provides a method for obtaining high concentration carbon dioxide flue gas based on calcining cement clinker, and the system 100 based on the above technical solution. The method specifically comprises the following steps:
the raw meal is heated and decomposed in the rotary kiln 110 provided with the electromagnetic induction device 113 to generate carbon dioxide gas, and is calcined into clinker.
The flue gas containing the decomposed carbon dioxide gas enters the first heat exchanging device 130 via the flue chamber 111. Clinker enters the air cooling device through the kiln hood 112 to exchange heat with air for cooling, and the air after heat exchange enters the second heat exchange device 140.
Before entering the rotary kiln 110, the raw materials are respectively put into the first heat exchange device 130 and the second heat exchange device 140 to exchange heat with the smoke and the air, and enter the rotary kiln 110 through the smoke chamber 111 to be calcined after the heat exchange, and the smoke and the air after the heat exchange are respectively discharged through the smoke pipeline 150 and the air pipeline 160; wherein the flue gas discharged through the flue gas pipeline 150 is high-concentration carbon dioxide flue gas, and the concentration of carbon dioxide in the flue gas is more than 80%.
When the carbon dioxide concentration monitored by the gas analyzer 115 is greater than the threshold value, the first fan 151 increases the rotation speed gradually until the rotation speed is remained when the carbon dioxide concentration is reduced to the threshold value, and the pressure value monitored by the pressure sensor 114 is always within the preset range value; in the above process, if the pressure value monitored by the pressure sensor 114 is greater than the upper limit of the preset range value but the carbon dioxide concentration does not decrease to the threshold value in the process of gradually increasing the rotation speed of the first fan 151, the second fan 161 starts to gradually decrease the rotation speed, and the rotation speed of the first fan 151 remains unchanged until the rotation speeds of the first fan 151 and the second fan 161 respectively stay at the rotation speeds when the carbon dioxide concentration decreases to the threshold value and the pressure value decreases to the preset range value; in the above process, if the carbon dioxide concentration of the second fan 161 is not reduced to the threshold value when the pressure value is smaller than the lower limit of the preset range value in the process of gradually reducing the rotation speed, the first fan 151 continues to gradually increase the rotation speed, and the rotation speed of the second fan 161 is kept unchanged; the above steps are repeated until the first fan 151 and the second fan 161 stay at the rotational speeds when the carbon dioxide concentration falls within the threshold value and the pressure value falls within the preset range value.
Other embodiments of the application will be apparent to and understood by those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the application being indicated by the following claims.
Claims (9)
1. A system for obtaining a high concentration carbon dioxide flue gas based on calcining cement clinker, the system comprising:
the tail part and the head part of the rotary kiln are respectively provided with a smoke chamber and a kiln head cover, and the rotary kiln surrounds the electromagnetic induction device along the length direction; a pressure sensor and a gas analyzer are arranged in the kiln head cover;
the kiln head cover is provided with a hot air pipeline for guiding out air after heat exchange;
the first heat exchange device is communicated to the smoke chamber and is used for exchanging heat between the raw meal and smoke generated by calcining the raw meal in the rotary kiln, and comprises a first raw meal inlet for introducing the raw meal and a first raw meal outlet for leading out the raw meal subjected to heat exchange to the smoke chamber;
the second heat exchange device is respectively communicated with the smoke chamber and the hot air pipeline and is used for exchanging heat between the raw meal and the air subjected to heat exchange, and comprises a second raw meal inlet for introducing the raw meal and a second raw meal outlet for leading out the raw meal subjected to heat exchange to the smoke chamber;
the flue gas pipeline is communicated with the first heat exchange device, is provided with a first fan and is used for discharging the flue gas subjected to heat exchange;
the air pipeline is communicated with the second heat exchange device, is provided with a second fan and is used for discharging air subjected to secondary heat exchange;
when the carbon dioxide concentration monitored by the gas analyzer is greater than a threshold value, the first fan gradually increases the rotating speed until the carbon dioxide concentration is reduced to the threshold value; if the pressure value monitored by the pressure sensor is larger than the upper limit of the preset range value in the process of gradually increasing the rotating speed of the first fan, the rotating speed of the second fan starts to be gradually reduced until the carbon dioxide concentration is reduced to the threshold value and the pressure value is reduced to be within the preset range value; if the carbon dioxide concentration of the second fan is not reduced to the threshold value in the process of gradually reducing the rotating speed when the pressure value is smaller than the lower limit of the preset range value, the first fan continues to gradually increase the rotating speed; and repeating the process until the concentration of the carbon dioxide is reduced to a threshold value and the pressure value is reduced to be within a preset range value.
2. The system of claim 1, further comprising:
control device, control device is connected respectively to pressure sensor, gas analyzer, first fan and second fan, control device is used for: when the carbon dioxide concentration monitored by the gas analyzer is greater than a threshold value, controlling the rotating speed of the first fan to be gradually increased until the rotating speed is remained when the carbon dioxide concentration can be reduced to the threshold value, wherein the pressure value monitored by the pressure sensor is within a preset range value; if the pressure value monitored by the pressure sensor is larger than the upper limit of the preset range value in the process of controlling the rotating speed of the first fan to be gradually increased, controlling the rotating speed of the second fan to be gradually reduced, and controlling the rotating speed of the first fan to be unchanged until the rotating speeds of the first fan and the second fan stay at the rotating speeds when the carbon dioxide concentration can be reduced to the threshold value and the pressure value is reduced to the preset range value; if the carbon dioxide concentration is not reduced to the threshold value in the process of controlling the rotation speed of the second fan to gradually decrease, controlling the rotation speed of the first fan to continuously gradually increase and controlling the rotation speed of the second fan to be unchanged; and repeating the process until the first fan and the second fan stay at the rotating speeds when the concentration of the carbon dioxide can be reduced to the threshold value and the pressure value is reduced to the preset range value.
3. A system according to claim 1 or 2, wherein the first heat exchange means comprises a plurality of cyclones arranged from top to bottom, the bottom material outlet of the lowermost cyclone being connected to the flue gas chamber, the gas inlet of the lowermost cyclone being connected to the flue gas chamber, the top gas outlet of the uppermost cyclone being connected to the flue gas duct; the gas outlet of the cyclone cylinder positioned below is communicated with the cyclone cylinder positioned above through a connecting pipeline, and the material outlet at the bottom of the cyclone cylinder positioned above is communicated with the connecting pipeline below;
wherein raw meal is fed into the connecting pipe located uppermost.
4. A system according to claim 3, wherein the second heat exchange means also comprises a plurality of cyclones arranged from top to bottom, the bottom material outlet of the lowermost cyclone being connected to the flue box, the gas inlet of the lowermost cyclone being connected to the hot air duct, the top gas outlet of the uppermost cyclone being connected to the air duct; the gas outlet of the cyclone cylinder positioned below is communicated with the cyclone cylinder positioned above through a connecting pipeline, and the material outlet at the bottom of the cyclone cylinder positioned above is communicated with the connecting pipeline below;
wherein raw meal is fed into the connecting pipe located uppermost.
5. The system of claim 4, wherein the air cooling device comprises a grate cooler, a bottom of which is provided with a blower for introducing air.
6. The system of claim 5, wherein the ratio of raw meal input to the first heat exchange device and the second heat exchange device is 1: (2-5).
7. The system of claim 1, wherein flue gas exiting the flue gas duct is further processed via a dust collector, and the processed flue gas is communicable to a carbon dioxide capture system.
8. The system according to claim 1, characterized in that the flue gas duct and/or the air duct is also connected to a waste heat boiler.
9. A method for obtaining a high concentration carbon dioxide flue gas based on calcined cement clinker, based on a system according to any one of claims 1 to 8, characterized in that the method comprises:
the raw materials are heated and decomposed in a rotary kiln provided with an electromagnetic induction device to generate carbon dioxide gas, and are calcined into clinker;
flue gas containing carbon dioxide gas generated by decomposition enters a first heat exchange device through a flue gas chamber, clinker enters an air cooling device through a kiln hood to exchange heat with air for cooling, and the air after heat exchange enters a second heat exchange device;
before entering the rotary kiln, the raw materials are respectively put into a first heat exchange device and a second heat exchange device to exchange heat with smoke and air, and enter the rotary kiln through a smoke chamber to be calcined after heat exchange, and the smoke and air after heat exchange are respectively discharged through a smoke pipeline and an air pipeline; the flue gas exhausted by the flue gas pipeline is high-concentration carbon dioxide flue gas, and the concentration of carbon dioxide in the flue gas is more than 80%;
when the carbon dioxide concentration monitored by the gas analyzer is greater than a threshold value, the first fan gradually increases the rotating speed until the rotating speed stays at the rotating speed when the carbon dioxide concentration is reduced to the threshold value, and the pressure value monitored by the pressure sensor is always within a preset range value; in the process, if the pressure value monitored by the pressure sensor is larger than the upper limit of the preset range value but the carbon dioxide concentration does not decrease to the threshold value in the process of gradually increasing the rotating speed, the second fan starts to gradually decrease the rotating speed, and the rotating speed of the first fan is kept unchanged until the first fan and the second fan respectively stay at the rotating speeds when the carbon dioxide concentration decreases to the threshold value and the pressure value decreases to the preset range value; in the above process, if the carbon dioxide concentration of the second fan is not reduced to the threshold value when the pressure value is smaller than the lower limit of the preset range value in the process of gradually reducing the rotating speed, the first fan continues to gradually increase the rotating speed, and the rotating speed of the second fan is kept unchanged; repeating the steps until the first fan and the second fan stay at the rotating speeds when the carbon dioxide concentration is reduced to the threshold value and the pressure value is reduced to the preset range value.
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