DEVICE AND METHOD FOR PRODUCING CEMENT CLINKER BY TOTAL OXYGEN COMBUSTION

Abstract

DEVICE AND METHOD FOR PRODUCING CEMENT CLINKER BY TOTAL OXYGEN COMBUSTION This publication provides a device for producing cement clinker by total oxygen combustion. The device includes: a rotary kiln, a decomposition kiln, a gas cooling device, and a carbon dioxide collection device. A second pipe port is connected to a second pipe, and the second pipe is equipped with a second oxygen inlet. A third pipe port is connected to the third pipe, and the third pipe is equipped with a third oxygen inlet. A cooling gas inlet from the gas cooling device includes a first oxygen inlet and a carbon dioxide inlet, and a cooling gas outlet is connected to the second and third pipes separately.In the publication, the circulating O2 and CO2 flue gases are rationally matched in the rotary kiln and the decomposition kiln, thus enabling heat recovery, optimizing combustion conditions in both the rotary and decomposition kilns, and effectively reducing carbon capture costs in cement production. The final flue gases obtained after combustion contain a high concentration of CO2, which can be collected and absorbed through adsorption and distillation. Operational costs for adsorption and distillation can be reduced by 47%, and capital costs by 35%. (Drawing from the abstract: Figure 1).

Description

Title of the invention: DEVICE AND METHOD CEMENT CLINKER PRODUCTION BY TOTAL OXYGEN COMBUSTION technical field

[0001] The publication relates to the technical field of construction materials, and in particular to a device and a process for the production of cement clinker by total oxygen combustion. PREVIOUS ART

[0002] The cement industry is the third largest emitter of CO2 in the world. The majority of its CO2 emissions come from the high energy and resource consumption used in cement production. In China, CO2 emissions from the cement industry are second only to those from the power generation and steel industries. Green and low-carbon technologies applied to the cement industry promote zero-carbon emissions and play a crucial role in China's achievement of the dual goals of peak carbon and carbon neutrality.

[0003] It is generally believed in China and abroad that carbon capture applications, and the technologies for their use and storage, are the only way to achieve carbon neutrality for the cement industry. However, air is usually used in the cement industry to promote combustion, resulting in a low concentration (20%-30%) of CO2 in the flue gases. Thus, a solvent absorption process must be used in CO2 capture, which is operationally extremely expensive. If the combustion-promoting air is replaced by high-purity oxygen, and the mean flux and heat transfer characteristics of a kiln are adjusted via flue gas circulation, flue gases with a high concentration of CO2 can be obtained, and the CO2 can be captured via adsorption and distillation.Compared to solvent absorption, the operational costs of adsorption and distillation can be reduced by 47% and investment costs by 35%. Thus, as a very promising technological approach to CO2 capture, total oxygen combustion technology enjoys the advantage of producing high-concentration CO2 streams and more efficient and economical CO2 capture.

[0004] In the prior art, when the fuel is burned at a high concentration of CO2, the flame temperature is lower than that of air combustion, and the speed The combustion rate is slower. With an increased O2 concentration, the flame temperature rises rapidly. However, an excessive O2 concentration leads to an excessively high combustion flame temperature and a risk of deflagration. Furthermore, due to an irrational O2 injection position, the O2 and fuel are not uniformly mixed, resulting in a partial high-temperature zone and a partial low-temperature zone. This affects the efficiency and stability of the combustion reaction. Incorrect O2 injection quantity and position are the major problems facing current total oxygen combustion.

[0005] Since current total oxygen combustion technology still suffers from flaws in the injection position and the ratio of injected O2, the combustion process is unstable, and it is impossible to fully realize the advantages of total oxygen combustion. To overcome the aforementioned problems, this publication provides a method for injecting oxygen during total oxygen combustion. By optimizing the O2 injection position and regulating the O2 mixing ratio at a high CO2 concentration in the flue gases, combustion stability is improved while carbon capture costs are reduced. Summary of the invention

[0006] In order to address the problems of high cost and low efficiency of carbon capture in a cement production process, the publication provides a device and a process for producing cement clinker by total oxygen combustion. The publication is implemented using the following technical plan:

[0007] A device for producing cement clinker by total oxygen combustion, comprising:

[0008] a rotary kiln used to produce cement clinker, in which the rotary kiln includes a rotary kiln feed port, a rotary kiln discharge port, a rotary kiln flue gas outlet, a burner, and a second pipe port; and the second pipe port is connected to a second pipe, the second pipe is provided with a second oxygen inlet, and the second oxygen inlet is used to introduce oxygen into the second pipe;

[0009] a decomposition furnace used to preheat a raw material and decompose the carbonate in the raw material, wherein the decomposition furnace comprises a raw material inlet, a rotary kiln flue gas inlet, a third conduit port, and a decomposition furnace outlet; the third conduit port is connected to the third conduit, and the third conduit is provided with a third oxygen inlet, and the third oxygen inlet is used to introduce oxygen into the third conduit; the flue gas inlet of the rotary kiln is connected to the rotary kiln's combustion gas outlet; and the decomposition kiln outlet is connected to the rotary kiln's feed port, and the decomposition kiln outlet is further connected to the tail gas outlet;

[0010] a gas cooling device, wherein the gas cooling device is connected to the discharge port of the rotary kiln; the gas cooling device is used to cool the material produced at the discharge port of the rotary kiln; the cooling device comprises a cooling gas inlet and a cooling gas outlet; the cooling gas inlet comprises a first oxygen inlet and a carbon dioxide inlet; the cooling gas outlet is connected to the second and third lines separately; and

[0011] a carbon dioxide collection device, in which the carbon dioxide collection device is connected to the tail gas outlet; and the carbon dioxide collection device is used to collect carbon dioxide from the combustion gases produced at the tail gas outlet.

[0012] Optionally, a grid cooler is used as a gas cooling device.

[0013] The first oxygen inlet and the carbon dioxide inlet are both located at the base of the grid cooler.

[0014] Optionally, the burner includes a burner carrier gas inlet, a fuel inlet, and a burner outlet; the carrier gas containing oxygen and carbon dioxide is conveyed into the burner through the carrier gas inlet and is mixed with the fuel and then burned at the burner outlet; and the volume fraction of oxygen in the carrier gas is 33%-38%, and the volume fraction of carbon dioxide is 50%-53%.

[0015] The gas is supplied from the second line at the burner outlet to promote combustion.

[0016] Optionally, a carbon dioxide adsorption and distillation device is used as a carbon dioxide collection device.

[0017] Optionally, the tail gas outlet is connected to a circulating flue gas port, and the circulating flue gas port is connected to the burner and the exhaust gas cooling device. The carbon dioxide supply to the exhaust gas cooling device uses the flue gases conveyed through the circulating flue gas port, and the carbon dioxide content is approximately 80%. In the burner, the oxygen and the flue gases conveyed through the circulating flue gas port are mixed to form a carrier gas, and then the carrier gas is mixed with the fuel for combustion.

[0018] Optionally, the third oxygen inlet is provided at a termination of the third proximal conduit of the gas cooling device.

[0019] The second oxygen inlet is provided at a termination of the second proximal conduit of the gas cooling device.

[0020] Optionally, the cement clinker production device by total oxygen combustion includes an oxygen preparation device. The first oxygen inlet, the second oxygen inlet, and the third oxygen inlet are all connected to the oxygen preparation device.

[0021] In a process for producing cement clinker by total oxygen combustion, production is carried out by the cement clinker production device by total oxygen combustion. The process comprises the following steps:

[0022] step 1), convey oxygen into a gas cooling device via a first oxygen inlet; convey carbon dioxide into the gas cooling device via a carbon dioxide inlet; and mix carbon dioxide and oxygen in the gas cooling device to form a first mixed gas, convey the first mixed gas into a second line and a third line separately via a gas cooling outlet;

[0023] step 2), conveying oxygen into the second line via a second oxygen inlet to mix it with the first mixed gas in the second line, forming a second mixed gas, and conveying the second mixed gas into a rotary kiln via the second line port to promote combustion in a burner; and enabling the combustion gas in the rotary kiln to enter a decomposition kiln via the rotary kiln's combustion gas outlet; and

[0024] step 3), convey the oxygen into the third conduit via a third oxygen inlet in order to mix it with the first mixed gas, to form a third mixed gas, and convey the third mixed gas into the decomposition furnace via a third conduit port; and produce combustion gas and material in the decomposition furnace from the decomposition furnace discharge port, allow the material in the decomposition furnace to enter the rotary furnace via a rotary furnace feed port, allow the combustion gas from the decomposition furnace to enter the carbon dioxide collection device via a tail gas outlet, and collect the carbon dioxide.

[0025] Optionally, the volume fraction of oxygen in the first mixed gas is 18%-22%.

[0026] Optionally, the volume fraction of oxygen in the second mixed gas is 33%-38%.

[0027] Optionally, the volume fraction of oxygen in the third mixed gas is 25%-30%.

[0028] The aforementioned fuel is coal.

[0029] Publication enjoys the following advantageous effects:

[0030] In the publication, the circulating O2 and CO2 flue gases are rationally matched in the rotary kiln and the decomposition kiln, thereby implementing heat recovery, optimizing combustion conditions in the rotary kiln and the decomposition kiln, and effectively reducing carbon capture costs in cement production. The flue gases ultimately obtained after combustion contain a high concentration of CO2, which can be collected and absorbed by adsorption and distillation. The operating costs of adsorption and distillation can be reduced by 47%, and the investment costs by 35%.

[0031] In the publication, oxygen-enriched injection is carried out in the gas cooling device, so that O2 can be fully mixed with the high CO2 combustion gas before the combustion reaction, the high partial temperature caused by a high partial concentration of O2 is avoided, and the stability of the combustion process is improved.

[0032] According to the publication, a control mechanism is provided for the O2 concentration in the rotary kiln and the decomposition kiln separately, so that the O2 ratio can be precisely controlled, and the requirements for different oxygen concentrations in the decomposition kiln and the rotary kiln can be met. BRIEF DESCRIPTION OF THE FIGURES

[0033] In order to illustrate more clearly the technical solutions of the specific embodiments of the publication or related art, the accompanying figures required for the description of the specific embodiments or related art are briefly described below. Of course, the accompanying figures in the following description constitute several embodiments of the publication, and a person skilled in the art can create other figures from these accompanying figures without creative effort.

[0034] Fig. 1 is a schematic structural diagram of the publishing device;

[0035] Figure 2 is a schematic structural diagram of a burner in a furnace rotary; and

[0036] Fig. 3 is a schematic diagram of a gas cooling device. DETAILED DESCRIPTION

[0037] Various embodiments of the publication are described in detail. These detailed descriptions should not be considered as limiting the publication, and should be understood as more detailed descriptions of certain aspects, features, and implementation solutions of the publication. It is important to understand that the terms used in the publication are intended solely to describe specific embodiments, and not to limit the publication.

[0038] Furthermore, it should be understood that each intermediate value between an upper and lower limit of a numeric range in the publication is more specifically included. Any stated value or any intermediate value within a given range, as well as any other stated value or each lower range between the intermediate values ​​within the range, are also included in the publication. The upper and lower limits may be included independently or excluded from the range.

[0039] Except where otherwise specified, all technical and scientific terms used herein have the same meanings as those ordinarily understood by a person skilled in the art to whom the publication relates. Although the publication describes only preferred processes and materials, any process or material similar or equivalent to those described herein may also be used in an implementation or trial of the publication.

[0040] The words "include", "comprise", "have", "contain", etc. used herein are open-ended formulations and indicate inclusion without limitation. The gas concentrations mentioned in the following examples are all measured as volume fractions. Example 1

[0041] A cement clinker production device by total oxygen combustion as shown in Figures 1-3, comprising: a rotary kiln 1, a decomposition kiln 2, a gas cooling device 3 and a carbon dioxide collection device 4.

[0042] The rotary kiln 1 is used to produce cement clinker. The rotary kiln includes a rotary kiln feed port 11, a rotary kiln discharge port 12, a rotary kiln flue gas outlet 13, a burner 14, and a second line port 15. The second line port 15 is connected to a second line 151. The second line 151 is provided with a second oxygen inlet 152. The second oxygen inlet is arranged at the termination of the second proximal line of the gas cooling device. The burner 14 is used to heat the rotary kiln. The burner 14 includes a burner carrier gas inlet 141, a fuel inlet 142, and a burner outlet 143. Gas is supplied from the second line 151 to the burner outlet 143 to promote combustion.The carrier gas containing oxygen and carbon dioxide is delivered to the burner via the carrier gas inlet 141 and is mixed with the fuel and then burned at the burner outlet; .

[0043] The decomposition furnace 2 is used to preheat a raw material and decompose the carbonate in the raw material. The decomposition furnace includes a raw material inlet (not shown in the figure), a combustion gas inlet from the rotary kiln 21, a third line port 22, and a decomposition furnace outlet 23. During operation, a mixed raw material comprising the raw material and fuel is added from the raw material inlet and burned in the decomposition furnace. The carbonate in the raw material is preheated and decomposed. The third line port 22 is connected to the third line 221. The third line 221 is provided with a third oxygen inlet 222. The third oxygen inlet is arranged at a termination of the proximal third line of the gas cooling device.The flue gas inlet of the rotary kiln 21 is connected to the flue gas outlet of the rotary kiln 13, so that the rotary kiln's flue gases can enter the decomposition kiln from the rotary kiln's flue gas inlet 21. The decomposition kiln's outlet 23 is connected to the rotary kiln's feed port, and the decomposition kiln's outlet 23 is further connected to a tail gas outlet 231. The tail gas outlet 231 is connected to the carbon dioxide collection device 4. The tail gas outlet 231 is connected to the circulating flue gas port 232, which is connected to the burner 14 and the gas cooling device 3, and is used to deliver the required carbon dioxide to the burner and the gas cooling device.In the carrier gas formed by mixing oxygen and circulating combustion gases, the volume fraction of oxygen is 33%-38%, and the volume fraction of carbon dioxide is 50%-53%.

[0044] The gas cooling device 3 is arranged. A grid cooler is used as the gas cooling device 3. The gas cooling device 3 is connected to the discharge port of the rotary kiln 12 and is used to cool the material produced at the outlet of the rotary kiln 12. The cooling device 3 includes a cooling gas inlet and a cooling gas outlet 33. The cooling gas inlet includes a first oxygen inlet 32 ​​and a carbon dioxide inlet 31. The first oxygen inlet and the carbon dioxide inlet are located at the base of the grid cooler. The cooling gas outlet is connected to the second line 151 and the third line 221 separately.

[0045] The carbon dioxide collection device 4 is provided. A carbon dioxide adsorption and distillation device is used as the carbon dioxide collection device 4. The carbon dioxide collection device is connected to the tail gas outlet. The carbon dioxide collection device 4 is used to collect carbon dioxide from the combustion gases produced at the tail gas outlet.

[0046] The aforementioned fuel is coal.

[0047] One implementation process of the publication is as follows: in a process for producing cement clinker by total oxygen combustion, production is carried out by the cement clinker production device by total oxygen combustion. The process comprises the following steps:

[0048] step 1), oxygen is routed into a gas cooling device via a first oxygen inlet; the circulating combustion gas is routed into the gas cooling device via a carbon dioxide inlet; and the carbon dioxide and oxygen are mixed in the gas cooling device to form a first mixed gas, and the first mixed gas is routed into a second line and a third line separately via a gas cooling outlet.

[0049] step 2), oxygen is routed into the second line via a second oxygen inlet in order to mix it with the first mixed gas in the second line, a second mixed gas is formed, and the second mixed gas is routed into a rotary kiln via the second line port in order to promote combustion in a burner; and the combustion gas in the rotary kiln enters a decomposition kiln via the rotary kiln combustion gas outlet.

[0050] step 3), oxygen is routed into the third line via a third oxygen inlet in order to mix it with the first mixed gas, a third mixed gas is formed, and the third mixed gas is routed into the decomposition furnace via a third line port; combustion gas and material are produced from the discharge port of the decomposition furnace, the material in the decomposition furnace enters the rotary furnace via a rotary furnace feed port, the combustion gas from the decomposition furnace enters the carbon dioxide collection device via a tail gas outlet, and the carbon dioxide is collected.

[0051] The oxygen volume fraction in the first mixed gas is 18%-22%. The oxygen volume fraction in the second mixed gas is 33%-38%. The oxygen volume fraction in the third mixed gas is 25%-30%.

[0052] Thanks to the device, the carbon dioxide concentration in the flue gas conveyed to the carbon dioxide collection device can reach approximately 80%. Due to the high concentration, the adsorption and distillation process can be used to recover the carbon dioxide. In the prior art, the CO2 concentration of the flue gas was 20%–30%, and the CO2 is generally captured by a solvent absorption process. The process is suitable for recovering carbon dioxide from flue gas containing a Carbon dioxide recovery is characterized by low concentrations and complex processes with high investment and operating costs. Adsorption and distillation separate carbon dioxide from other gases based on their boiling points. Heavier components, with higher boiling points than carbon dioxide, are removed by various adsorbents, while lighter components are extracted by distillation, leaving only carbon dioxide with a purity of 99.99% or higher. It is estimated that operating costs and investment costs can be reduced by 45.7% and 36.4%, respectively, by using adsorption and distillation equipment instead of solvent absorption equipment to recover carbon dioxide.

[0053] In the publication, oxygen-enriched injection is carried out in the exhaust gas cooling device, so that the O2 can be fully mixed with the high-CO2 combustion gases before the combustion reaction. This avoids the high partial temperature caused by a high partial concentration of O2 and improves the stability of the combustion process. If the oxygen and combustion gases are not mixed beforehand in the cooling device, all the oxygen may be mixed with the combustion gases in the second and third lines, resulting in a heterogeneous mixture. In this case, a partially high oxygen concentration and a partially low oxygen concentration are likely to occur, and complete combustion of the fuel is not facilitated. Example 2

[0054] Based on the device of Example 1, cement clinker is produced by total oxygen combustion, thus reducing CO2 capture costs while improving the combustion stability of a rotary kiln and a decomposition kiln. The specific steps are as follows:

[0055] Step 1), oxygen is conveyed into a gas cooling device via a first oxygen inlet; the circulating combustion gas is conveyed into the gas cooling device via a carbon dioxide inlet; and the carbon dioxide and oxygen are mixed in the gas cooling device to form a first mixed gas, the concentration of O2 in the first mixed gas is 21.2%, and the first mixed gas is conveyed into a second line and a third line separately via a gas cooling outlet.

[0056] Step 2), oxygen is conveyed into the second line via a second oxygen inlet to mix it with the first mixed gas in the second line, a second mixed gas is formed, the O2 concentration in the second mixed gas is 35.4%, and the second mixed gas is conveyed into a rotary furnace via the second line port to promote combustion in a burner; and the gas of Combustion in the rotary kiln enters a decomposition kiln via the combustion gas outlet of the rotary kiln.

[0057] Step 3), oxygen is routed into the third line via a third oxygen inlet in order to mix it with the first mixed gas, a third mixed gas is formed, the concentration of O2 in the third mixed gas is 27.0%, and the third mixed gas is routed into the decomposition furnace via a third line port; combustion gas and material are produced from the discharge port of the decomposition furnace, the material in the decomposition furnace enters the rotary furnace via a feed port of the rotary furnace, the combustion gas from the decomposition furnace enters the carbon dioxide collection device via a tail gas outlet, and the carbon dioxide is collected.

[0058] Measurements have shown that the O2 concentration in the tailpipe flue gas is 2.8% and the CO2 concentration is 78.4%. Temperatures in the rotary kiln and the decomposition furnace are maintained within the expected range, and no partial temperature increases or severe temperature fluctuations occur. The combustion process is stable. The average NOx concentration in the decomposition furnace is 330 mg / m³, and the average NOx concentration in the rotary kiln is 900 mg / m³. Example 3

[0059] Based on the structure of Example 1, a cement production line is subjected to a total oxygen combustion transformation in order to reduce CO2 capture costs and improve the combustion stability of a rotary kiln and a decomposition kiln. The specific steps are as follows:

[0060] Step 1), oxygen is conveyed into a gas cooling device via a first oxygen inlet; the circulating combustion gas is conveyed into the gas cooling device via a carbon dioxide inlet; and the carbon dioxide and oxygen are mixed in the gas cooling device to form a first mixed gas, the concentration of O2 in the first mixed gas is 19.6%, and the first mixed gas is conveyed into a second line and a third line separately via a gas cooling outlet.

[0061] Step 2), oxygen is routed into the second line via a second oxygen inlet in order to mix it with the first mixed gas in the second line, a second mixed gas is formed, the concentration of O2 in the second mixed gas is 33.7%, and the second mixed gas is routed into a rotary kiln via the second line port in order to promote combustion in a burner; and the combustion gas in the rotary kiln enters a decomposition kiln via the combustion gas outlet of the rotary kiln.

[0062] Step 3), oxygen is routed into the third line via a third oxygen inlet in order to mix it with the first mixed gas, a third mixed gas is formed, the concentration of O2 in the third mixed gas is 25.2%, and the third mixed gas is routed into the decomposition furnace via a third line port; combustion gas and material are produced from the discharge port of the decomposition furnace, the material in the decomposition furnace enters the rotary furnace via a rotary furnace feed port, the combustion gas from the decomposition furnace enters the carbon dioxide collection device via a tail gas outlet, and the carbon dioxide is collected.

[0063] Measurements have shown that the O2 concentration in the tailpipe flue gas is 2.4% and the CO2 concentration is 80.5%. Temperatures in the rotary kiln and the decomposition furnace are maintained within the expected range, and no partial temperature increases or severe temperature fluctuations occur. The combustion process is stable. The average NOx concentration in the decomposition furnace is 320 mg / m³, and the average NOx concentration in the rotary kiln is 940 mg / m³. Example 4

[0064] Based on the device of Example 1, cement clinker is produced by total oxygen combustion, thus reducing CO2 capture costs while improving the combustion stability of a rotary kiln and a decomposition kiln. The specific steps are as follows:

[0065] Step 1), oxygen is routed into a gas cooling device via a first oxygen inlet; the circulating combustion gas is routed into the gas cooling device via a carbon dioxide inlet; and the carbon dioxide and oxygen are mixed in the gas cooling device to form a first mixed gas, the concentration of O2 in the first mixed gas is 18.2%, and the first mixed gas is routed into a second line and a third line separately via a gas cooling outlet.

[0066] Step 2), oxygen is routed into the second line via a second oxygen inlet in order to mix it with the first mixed gas in the second line, a second mixed gas is formed, the concentration of O2 in the second mixed gas is 33.5%, and the second mixed gas is routed into a rotary kiln via the second line port in order to promote combustion in a burner; and the combustion gas in the rotary kiln enters a decomposition kiln via the rotary kiln combustion gas outlet.

[0067] Step 3), oxygen is conveyed into the third pipe via a third oxygen inlet in order to mix it with the first mixed gas, a third gas mixed gas is formed, the concentration of O2 in the third mixed gas is 25.1%, and the third mixed gas is routed into the decomposition furnace via a third pipe port; combustion gas and material are produced from the discharge port of the decomposition furnace, the material in the decomposition furnace enters the rotary furnace via a rotary furnace feed port, the combustion gas from the decomposition furnace enters the carbon dioxide collection device via a tail gas outlet, and the carbon dioxide is collected.

[0068] Measurements have shown that the O2 concentration in the tailpipe flue gas is 2.3% and the CO2 concentration is 79.1%. Temperatures in the rotary kiln and the decomposition furnace are maintained within the expected range, and no partial temperature increases or severe temperature fluctuations occur. The combustion process is stable. The average NOx concentration in the decomposition furnace is 325 mg / m³, and the average NOx concentration in the rotary kiln is 890 mg / m³. Example 5

[0069] Based on the device of Example 1, cement clinker is produced by total oxygen combustion, thus reducing CO2 capture costs while improving the combustion stability of a rotary kiln and a decomposition kiln. The specific steps are as follows:

[0070] Step 1), oxygen is conveyed into a gas cooling device via a first oxygen inlet; the circulating combustion gas is conveyed into the gas cooling device via a carbon dioxide inlet; and the carbon dioxide and oxygen are mixed in the gas cooling device to form a first mixed gas, the concentration of O2 in the first mixed gas is 21.7%, and the first mixed gas is conveyed into a second line and a third line separately via a gas cooling outlet.

[0071] Step 2), oxygen is routed into the second line via a second oxygen inlet in order to mix it with the first mixed gas in the second line, a second mixed gas is formed, the concentration of O2 in the second mixed gas is 37.6%, and the second mixed gas is routed into a rotary kiln via the second line port in order to promote combustion in a burner; and the combustion gas in the rotary kiln enters a decomposition kiln via the rotary kiln combustion gas outlet.

[0072] Step 3), oxygen is conveyed into the third line via a third oxygen inlet to mix it with the first mixed gas, a third mixed gas is formed, the O2 concentration in the third mixed gas is 29.8%, and the third mixed gas is conveyed into the decomposition furnace via a port of third conduit; combustion gas and material are produced from the discharge port of the decomposition furnace, the material in the decomposition furnace enters the rotary furnace via a feed port of the rotary furnace, the combustion gas from the decomposition furnace enters the carbon dioxide collection device via a tail gas outlet, and the carbon dioxide is collected.

[0073] Measurements have shown that the O2 concentration in the tailpipe flue gas is 2.9% and the CO2 concentration is 80.3%. Temperatures in the rotary kiln and the decomposition furnace are maintained within the expected range, and no partial temperature increases or severe temperature fluctuations occur. The combustion process is stable. The average NOx concentration in the decomposition furnace is 340 mg / m³, and the average NOx concentration in the rotary kiln is 950 mg / m³. Comparative example 1

[0074] The additional amount of oxygen from the second oxygen inlet of Example 2 is increased, and the oxygen ratio of the second mixed gas in Example 2 is increased to 40%. The other steps are the same as those in Example 2. As a result, the oxygen concentration in the rotary kiln is excessive, leading to a partial temperature rise and an increased NOx concentration. Measurements show that the average NOx concentration in the decomposition kiln is 450 mg / m³, and the average NOx concentration in the rotary kiln is 1090 mg / m³. The increased nitrogen oxide concentration results in higher pressure and costs for denitrification of the denitrification device. Comparative example 2

[0075] The additional amount of oxygen from the second oxygen inlet of Example 2 is increased, and the oxygen ratio of the third mixed gas in Example 2 is increased to 33%. The other steps are the same as those in Example 2. As a result, the oxygen concentration in the decomposition furnace is excessive, leading to a partial temperature rise and an increased NOx concentration. Measurements show that the average NOx concentration in the decomposition furnace is 530 mg / m³, and the average NOx concentration in the rotary kiln is 950 mg / m³. The increased nitrogen oxide concentration results in higher pressure and denitrification costs for the denitrification device.

[0076] Through comparison between examples and comparative examples, according to the publication, a regulation mechanism is provided for the O2 concentration in the rotary kiln and the decomposition kiln separately, so that the O2 ratio can be precisely controlled, and the different oxygen concentration requirements in the decomposition kiln and the rotary kiln can be met. A quantity Appropriate supplemental oxygen can effectively prevent excessive nitrogen oxide production, and reduce the pressure and denitrification costs of a denitrification device.

[0077] Obviously, the above examples are given for illustrative purposes only and are not intended to limit embodiments. A person skilled in the art can make variations or modifications in various forms based on the above description. It is neither necessary nor possible to list all embodiments. Any variation or modification that is clearly derived from them is covered by the scope of protection of this publication.

Claims

1. Demands A device for the production of cement clinker by total oxygen combustion, comprising: a rotary kiln used to produce cement clinker, in which the rotary kiln includes a rotary kiln feed port, a rotary kiln discharge port, a rotary kiln flue gas outlet, a burner, and a second pipe port; and the second pipe port is connected to a second pipe, the second pipe is provided with a second oxygen inlet, and the second oxygen inlet is used to introduce oxygen into the second pipe; a decomposition furnace used to preheat a raw material and decompose the carbonate in the raw material, wherein the decomposition furnace comprises a raw material inlet, a rotary kiln flue gas inlet, a third pipe port, and a decomposition furnace outlet; the third pipe port is connected to the third pipe, and the third pipe is provided with a third oxygen inlet, and the third oxygen inlet is used to introduce oxygen into the third pipe; the rotary kiln flue gas inlet is connected to the rotary kiln flue gas outlet; and the decomposition furnace outlet is connected to the rotary kiln feed port, and the decomposition furnace outlet is further connected to the tail gas outlet; a gas cooling device, wherein the gas cooling device is connected to the discharge port of the rotary kiln; the gas cooling device is used to cool the material produced at the discharge port of the rotary kiln; the cooling device comprises a cooling gas inlet and a cooling gas outlet; the cooling gas inlet comprises a first oxygen inlet and a carbon dioxide inlet; the cooling gas outlet is connected to the second and third lines separately; and a carbon dioxide collection device, wherein the carbon dioxide collection device is connected to the tail gas outlet; and the carbon dioxide collection device carbon is used to collect carbon dioxide from the combustion gases produced at the tailpipe outlet.

2. A device for producing cement clinker by total oxygen combustion according to claim 1, wherein a grid cooler is used as a gas cooling device; and the first oxygen inlet and the carbon dioxide inlet are both located at the base of the grid cooler.

3. A device for producing cement clinker by total oxygen combustion according to claim 1, wherein the burner comprises a burner carrier gas inlet, a fuel inlet, and a burner outlet; the carrier gas containing oxygen and carbon dioxide is conveyed into the burner by the carrier gas inlet and is mixed with the fuel and then burned at the burner outlet; and the volume fraction of oxygen in the carrier gas is 33%-38%, and the volume fraction of carbon dioxide is 50%-53%; and the gas is supplied from the second line at the burner outlet to promote combustion.

4. A device for producing cement clinker by total oxygen combustion according to claim 1, wherein a carbon dioxide adsorption and distillation device is used as a carbon dioxide collection device; and preferably, the tail gas outlet is connected to a circulating combustion gas port, and the circulating combustion gas port is connected to the burner and the gas cooling device.

5. A cement clinker production device by total oxygen combustion according to claim 1, wherein the third oxygen inlet is provided at a termination of the third proximal conduit of the gas cooling device; and the second oxygen inlet is provided at a termination of the second proximal conduit of the gas cooling device.

6. A device for producing cement clinker by total oxygen combustion according to claim 1, further comprising an oxygen preparation device, wherein the first oxygen inlet, the second oxygen inlet, and the third

7.

8.

9. Oxygen supply lines are all connected to the oxygen preparation device. A process for producing cement clinker by total oxygen combustion, wherein production is carried out by the cement clinker production device by total oxygen combustion according to any one of claims 1-5, and the process comprises the following steps: step 1), convey oxygen into a gas cooling device via a first oxygen inlet; convey carbon dioxide into the gas cooling device via a carbon dioxide inlet; and mix carbon dioxide and oxygen in the gas cooling device to form a first mixed gas, convey the first mixed gas into a second line and a third line separately via a gas cooling outlet; step 2), convey oxygen into the second line via a second oxygen inlet to mix it with the first mixed gas in the second line, forming a second mixed gas, and convey the second mixed gas into a rotary kiln via the second line port to promote combustion in a burner; and allow the combustion gas in the rotary kiln to enter a decomposition kiln via the rotary kiln's combustion gas outlet; and step 3), route oxygen into the third line via a third oxygen inlet to mix it with the first mixed gas, to form a third mixed gas, and route the third mixed gas into the decomposition furnace via a third line port; and produce combustion gas and material in the decomposition furnace from the decomposition furnace discharge port, allow the material in the decomposition furnace to enter the rotary kiln via a rotary kiln feed port, allow the combustion gas from the decomposition furnace to enter the carbon dioxide collection device via a tail gas outlet, and collect the carbon dioxide. A process according to claim 7, wherein the oxygen volume fraction in the first mixed gas is 18%-22%. A process according to claim 7, wherein the oxygen volume fraction in the second mixed gas is 33%-38%.

10. A process according to claim 7, wherein the volume fraction of oxygen in the third mixed gas is 25%-30%.

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