WO2022099532A1 - Cement kiln system and method for preparing cement clinker - Google Patents

Abstract

A cement kiln system and method, the system comprising a smoke chamber (1), a rotary kiln (2), a cooling machine (3), a first raw material pre-heating pre-decomposition system, and a second raw material pre-heating pre-decomposition system, the smoke chamber (1), the rotary kiln (2), and the cooling machine (3) being in communication sequentially, the first raw material pre-heating pre-decomposition system and the second raw material pre-heating pre-decomposition system respectively being in communication with the smoke chamber (1), and a feeding pipe of a top cyclone separator of the second raw material pre-heating pre-decomposition system being in communication with a feeding port of a top cyclone separator of the first raw material pre-heating pre-decomposition system. The present invention solves the technical problems in existing cement kiln systems of the Co₂ purification operation flow being complex due to the low concentration of CO₂, and the SO₂ content in the flue gas entering the CO₂ purification system being high due to the use of inferior raw materials, such that the CO₂ purification system requires desulphurisation treatment of the flue gas, greatly increasing the investment costs and running costs of the CO₂ purification system.

Description

A kind of cement kiln system and method for preparing cement clinker technical field

The invention relates to the technical field of carbon emission reduction in the cement industry, in particular to a cement kiln system and a method for preparing cement clinker.

Background technique

As a major greenhouse gas, the massive emission of CO ₂ aggravates the global greenhouse effect. All countries in the world are generally faced with the arduous task of reducing carbon emissions and mitigating global climate change. In order to better develop the global economy and protect the natural environment, countries around the world have successively formulated strategic goals for carbon emission reduction. In China, the cement industry has become the second largest source of _CO2 emissions after the power industry. According to statistics, the national output of cement clinker in 2018 was about 1.42 billion tons. Under the current technical level of about 0.84 tons of CO ₂ emissions per 1 ton of cement clinker produced in China, the CO ₂ emissions in 2018 have already exceeded close to 1.2 billion tons. Therefore, it is urgent to alleviate the problem of high _CO2 emissions in the cement industry.

There have been many reports on carbon emission reduction technologies at home and abroad, but these studies are mainly aimed at industries such as electricity, coal and steel, and there are relatively few reports on carbon emission reduction technologies in the cement industry. The current cement production process generally adopts the new dry production process, which mainly adopts the cement kiln system. The cement kiln system is specifically composed of a cooler, a burner, a rotary kiln, a cyclone preheater and a connecting air duct. Among them, the raw meal is preheated and heated up in the cyclone preheater, decomposed in the decomposition furnace, part of the fuel is burned in the decomposition furnace to provide the required heat for the decomposition of the raw meal, and the decomposed raw meal is heated by another part of the fuel in the rotary kiln It is calcined into cement clinker, and then the cement clinker is cooled to a suitable temperature by a cooler.

At present, the carbon emission reduction technical solutions that can be adopted in the cement industry are CO ₂ capture before combustion and CO ₂ capture after combustion. The pre-combustion capture of CO ₂ refers to the pretreatment of the fuel before combustion to separate the carbon in the fuel. Due to the characteristics of the cement clinker production process, a significant disadvantage of CO ₂ capture before combustion is that only the CO ₂ produced by the combustion of the fuel can be separated, while about 60% of the CO ₂ produced by the calcination of raw meal is emitted with the flue gas, that is, the raw material The _CO2 produced during the calcination of the feedstock is not treated. In addition, the pre-combustion _CO capture technology has very harsh conditions for hydrogen combustion in the clinker calcination process compared with other _CO capture technologies, and requires special design of the burner in the rotary kiln. Therefore, this technology plays an important role in carbon emission reduction in the cement industry. Feasibility is low. The post-combustion CO ₂ capture technology mainly refers to CO ₂ capture or separation of CO ₂ from the combustion flue gas. The existing main technologies include absorption method, adsorption method, membrane absorption method and mineral carbonization method. Due to the low concentration of CO ₂ in the flue gas, the subsequent purification operation process for CO ₂ in the flue gas is complicated, which greatly increases the investment cost and operating cost of the CO ₂ purification system.

In addition, in the process of producing cement in the cement kiln system, raw meal and fuel will bring sulfur impurities. The sulfur impurities mainly exist in the form of organic sulfide, inorganic sulfide (simple sulfide or complex sulfide) or sulfate. Sulfur can be ignored. The sulfur impurities brought by the fuel are generally absorbed by the active oxides in the calciner to form sulfite or sulfate, and then enter the rotary kiln through the smoke chamber; sulfur in the form of sulfate in the raw meal Impurities generally do not form SO ₂ gas in the cyclone preheater, and will eventually enter the rotary kiln. Part of the sulfate entering the rotary kiln will decompose and react at high temperature to generate SO ₂ gas, and part of the SO ₂ gas will pass through the cyclone preheater. The flue gas is discharged, and another part of SO2 gas is condensed _on the raw meal in the low temperature area of the flue chamber or cyclone separator, and enters the rotary kiln with the deposition of the raw meal, forming an internal circulation between the cyclone preheater and the rotary kiln, which is not decomposed. The sulfate will leave the rotary kiln with the cement clinker; the sulfur impurities in the raw meal in the form of organic sulfide, inorganic sulfide and other forms are generally oxidized at 300-600 ℃ to form SO ₂ gas, which mainly occurs in the cyclone preheating process. In the two-stage cyclone separator at the top of the heater and the air inlet pipe connected to the top two-stage cyclone separator; therefore, if the raw meal is made of low-quality raw materials with high sulfur content, the SO ₂ concentration emitted during the cement production process will be higher. However, the existing CO ₂ purification system is very sensitive to SO ₂ in the flue gas. Studies have shown that the SO ₂ concentration in the flue gas entering the CO ₂ purification system should be as low as possible, preferably within 10mg/Nm ³ , In order to ensure the stable operation and normal use of the CO ₂ purification system, the existing CO ₂ purification system needs to desulfurize the flue gas, which increases the investment cost and operating cost of the CO ₂ purification system.

SUMMARY OF THE INVENTION

In order to overcome the defects of the prior art, the present invention provides a cement kiln system and a method for preparing cement clinker, so as to solve the problem of subsequent purification of CO ₂ in the flue gas due to the low concentration of CO ₂ in the flue gas of the existing cement kiln system. The complex operation process and the use of inferior raw materials with high sulfur content in the raw meal lead to a high SO ₂ content in the flue gas entering the CO ₂ purification system, so that the CO ₂ purification system needs to desulfurize the flue gas, which greatly improves the efficiency of the flue gas. Technical issues of investment cost and operating cost of CO ₂ purification system.

The present invention is achieved through the following technical solutions:

A cement kiln system includes a smoke chamber, a rotary kiln and a cooler connected in sequence, a first burner is arranged on the rotary kiln, and the cement kiln system further includes a first raw meal preheating and predecomposition system and a second raw meal preheating system. Thermal pre-decomposition system, the first raw meal preheating and pre-decomposition system is a carbon dioxide self-enrichment system, the second raw meal pre-heating and pre-decomposition system is a conventional raw meal pre-heating and pre-decomposition system, and the first raw meal preheating and pre-decomposition system is The preheating and pre-decomposition system includes a pre-combustion furnace, a first decomposition furnace and a first row of cyclone preheaters;

A combustion-supporting medium inlet is provided on the pre-combustion furnace, a second burner is arranged on the pre-combustion furnace, and the bottom of the pre-combustion furnace is communicated with the cone of the first decomposition furnace;

A third burner is arranged on the first calcining furnace, and a first row of raw meal inlets is set on the first calcining furnace;

The air inlet of the bottom cyclone separator of the first row of cyclone preheaters is connected to the air outlet pipe of the first decomposition furnace, and the air outlet of the top cyclone separator of the first row of cyclone preheaters discharges low-temperature smoke The feed port of the top cyclone separator of the first row of cyclone preheaters is used for raw material feeding, and the discharge port of the bottom cyclone separator of the first row of cyclone preheaters is connected to the smoke room;

The second raw meal preheating and pre-decomposition system is communicated with the smoke chamber.

Further, the second raw meal preheating and pre-decomposition system includes a second calciner and a second row of cyclone preheaters, a fourth burner is arranged on the second calciner, and a second row is set on the second calciner. raw meal import;

The air inlet of the bottom cyclone separator of the second row of cyclone preheaters is connected to the air outlet pipe of the second decomposition furnace, and the air outlet of the top cyclone separator of the second row of cyclone preheaters discharges low-temperature smoke gas;

The feed port of the top cyclone separator of the second row of cyclone preheaters is used for raw material feeding, and the discharge port of the bottom end cyclone separator of the second row of cyclone preheaters is connected to the smoke chamber.

Further, the second raw meal preheating and pre-decomposition system further includes a third row of cyclone preheaters, and a third row of raw meal inlets is provided on the second precalciner;

The air inlet of the bottom cyclone separator of the third row of cyclone preheaters is connected to the air outlet pipe of the second decomposition furnace, and the air outlet of the top cyclone separator of the third row of cyclone preheaters discharges low-temperature smoke gas;

The feed port of the top cyclone separator of the third row of cyclone preheaters is used for raw material feeding, and the discharge port of the bottom cyclone separator of the third row of cyclone preheaters is connected to the smoke chamber.

Further, the feeding pipe of the top cyclone separator of the second row of cyclone preheaters or the third row of cyclone preheaters communicates with the feed port of the top cyclone separator of the first row of cyclone preheaters.

Further, the number of stages of the first row of cyclone preheaters is 3-7; the number of stages of the second row of cyclone preheaters is 3-7, and the number of stages of the third row of cyclone preheaters is 3-7. Numbers are grades 3-7.

Further, the first row of raw meal inlets includes one or more raw meal inlets;

A first material distribution valve is set at the feeding pipe of the penultimate second-stage cyclone separator from bottom to top of the first row of cyclone preheaters, and the first material distribution valve is connected to one of the raw meal inlets of the first row or multiple raw meal inlets.

Further, the first raw meal preheating and pre-decomposition system further includes a first conveying pipeline assembly, and the first conveying pipeline assembly includes a first branch pipeline, a second branch pipeline and a third branch pipeline;

The air inlets of the first branch pipe, the second branch pipe and the third branch pipe are communicated with the air outlet of the top cyclone separator of the first row of cyclone preheaters;

The exhaust port of the first branch pipe is communicated with the cooling equipment, the dust removal equipment, and the carbon dioxide purification system in sequence, and the exhaust port of the second branch pipe is communicated with the air outlet pipe of the first decomposition furnace. The exhaust port of the third branch pipeline is communicated with the combustion-supporting medium inlet.

Further, the first raw meal preheating and pre-decomposition system further includes an emergency discharge pipe, one end of the emergency discharge pipe is communicated with the bottom end of the first decomposition furnace, and the other end of the emergency discharge pipe communicated with the smoke chamber.

A method for preparing cement clinker using a cement kiln system, the method comprising the steps of:

When the cement kiln system is a CO2 self-accumulating precalciner:

The raw meal is fed into the second row of cyclone preheaters, the third row of cyclone preheaters and the first row of cyclone preheaters, and the raw meal and the flue gas undergo heat exchange and gas-solid separation in the cyclone preheater;

The raw meal preheated by the first row of cyclone preheaters enters the first calciner, and the raw meal preheated by the second row of cyclone preheaters and the third row of cyclone preheaters enters the second calciner;

The combustion-supporting medium enters the pre-combustion furnace from the combustion-supporting medium inlet of the pre-combustion furnace, and is used for the combustion of the fuel entering the pre-combustion furnace from the top of the pre-combustion furnace, and the combustion products enter the first decomposition furnace from the bottom of the pre-combustion furnace. The interior is pure oxygen combustion, and a large amount of heat released by the combustion is used for the endothermic decomposition of the raw meal in the first decomposition furnace to obtain hot raw meal and generate a large amount of flue gas. The flue gas generated in the first decomposition furnace enters the first column of cyclone preheater. The heat exchange with the raw meal in the heater becomes low-temperature flue gas. The low-temperature flue gas is discharged through the air outlet of the top cyclone separator of the first row of cyclone preheaters. The carbon dioxide concentration in the low-temperature flue gas is higher than 70%, and the SO ₂ concentration is less than 20 mg. /Nm ³ , the enrichment amount of carbon dioxide gas can be adjusted by adjusting the amount of raw meal fed into the first row of cyclone preheaters;

The raw meal in the second calciner is decomposed by endothermic heat to obtain hot raw meal, and a large amount of flue gas is generated. The flue gas in the second calciner enters the second row of cyclone preheaters and the third row of cyclone preheaters respectively. The heat exchange of raw meal becomes low-temperature flue gas. The low-temperature flue gas is discharged through the air outlet of the top cyclone separator of the second row of cyclone preheaters and the third row of cyclone preheaters respectively. The carbon dioxide concentration in the low-temperature flue gas is 25-35%. ;

The hot raw materials generated in the first and second calciners enter the rotary kiln through the smoke chamber, and are calcined in the rotary kiln to form cement clinker. The fuel in the rotary kiln is burned to generate kiln gas, and the cement clinker is cooled from the rotary kiln outlet. The kiln gas enters the second row of cyclone preheaters and the third row of cyclone preheaters respectively through the smoke chamber and the second calciner, and passes through the second row of cyclone preheaters and the third row of cyclone preheaters. The air outlet of the top cyclone separator of the three-row cyclone preheater is discharged as low-temperature flue gas;

When the cement kiln system is a conventional precalciner kiln, the first raw meal preheating and precalciner system stops working:

The raw meal is fed into the second row of cyclone preheaters and the third row of cyclone preheaters respectively, and the raw meal exchanges heat with the flue gas in the cyclone preheater;

The raw meal preheated by the second row of cyclone preheaters and the third row of cyclone preheaters enters the second decomposition furnace;

The raw meal is endothermic and decomposed in the second calcining furnace to obtain hot raw meal, and a large amount of flue gas is generated. The heat exchange of the material becomes low-temperature flue gas, and the low-temperature flue gas is discharged through the air outlet of the top cyclone separator of the second row of cyclone preheaters and the third row of cyclone preheaters respectively, and the carbon dioxide concentration in the low-temperature flue gas is 25-35%;

The hot raw meal enters the rotary kiln through the smoke chamber, and is calcined in the rotary kiln to form cement clinker. The fuel in the rotary kiln is burned to generate kiln gas. The cement clinker enters the cooler from the outlet of the rotary kiln, and exchanges heat with the air to obtain the cooled cement clinker. The kiln gas enters the second row of cyclone preheaters and the third row of cyclone preheaters through the smoke chamber and the second calciner in turn, and passes through the top cyclone separators of the second row of cyclone preheaters and the third row of cyclone preheaters. The air outlet is discharged as low temperature flue gas.

Further, the raw meal is fed into the second row of cyclone preheaters, the third row of cyclone preheaters and the first row of cyclone preheaters, and the raw meal undergoes heat exchange and gas solidification with the flue gas in the cyclone preheater. The separation specifically includes: feeding the raw meal into the second row of cyclone preheaters, the third row of cyclone preheaters and the first row of cyclone preheaters, where the raw meal exchanges heat and gas with the flue gas in the cyclone preheater. solid separation.

Further, the raw meal is fed into the second row of cyclone preheaters, the third row of cyclone preheaters and the first row of cyclone preheaters, and the raw meal undergoes heat exchange and gas solidification with the flue gas in the cyclone preheater. Separation specifically includes: feeding the raw meal into the second row of cyclone preheaters and the third row of cyclone preheaters respectively, and the raw meal of the second row of cyclone preheaters or the third row of cyclone preheaters passes through the top cyclone separator The feeding pipe is divided into two paths, one raw meal enters the second row of cyclone preheater or the third row of cyclone preheater, and the other raw meal enters the first row of cyclone preheater, and the raw meal is preheated in the cyclone. Heat exchange and gas-solid separation are carried out with flue gas in the device.

Further, the low-temperature flue gas discharged from the air outlet of the top cyclone separator of the first row of cyclone preheaters is divided into three paths. The first low-temperature flue gas enters the carbon dioxide purification system for purification after cooling and dust removal. The low-temperature flue gas of the first route is passed into the air outlet pipe of the first decomposition furnace, and the low-temperature flue gas of the third route is mixed with pure oxygen purchased from the outside or produced by the oxygen production system and passed into the pre-combustion furnace as a combustion-supporting medium.

Further, the bottom of the first calciner is communicated with the smoke chamber through an emergency discharge pipe.

Compared with the closest prior art, the technical solution of the present invention has the following beneficial effects:

In the cement kiln system provided by the present invention, the raw meal enters the first row of cyclone preheaters through the feeding pipe of the top cyclone separator of the second row of cyclone preheaters, and then enters the first row of cyclone preheaters after multiple gas-solid heat exchanges and separations. In the decomposition furnace, the combustion-supporting medium including pure oxygen obtained from the outsourcing or oxygen production system enters the pre-combustion furnace from the inlet of the combustion-supporting medium, and is used for the combustion of the fuel entering the pre-combustion furnace from the top of the pre-combustion furnace. The bottom of the combustion furnace enters the first decomposition furnace, and the first decomposition furnace is pure oxygen combustion, and the combustion releases a large amount of heat for the endothermic decomposition of the raw meal in the first decomposition furnace, obtaining hot raw meal, and generating a large amount of flue gas, heat The raw meal and the flue gas leave the first calciner and enter the cyclone separator at the bottom of the first row of cyclone preheaters, and then the hot raw meal is separated from the solid gas of the flue gas, and the flue gas moves upward through the first row of cyclone preheaters, and the The raw meal fed into the first row of cyclone preheaters undergoes multiple heat exchanges, and finally becomes low-temperature flue gas, and the carbon dioxide concentration in the low-temperature flue gas is above 70%, which simplifies the subsequent capture of CO ₂ in the cement kiln flue gas. The purification process greatly reduces the investment cost and operating cost of the CO ₂ purification system. The amount of raw meal fed into the first row of cyclone preheaters can be flexibly adjusted according to the market demand for carbon dioxide products, so as to achieve the purpose of carbon emission reduction in the cement industry, and the raw meal can be preheated and pre-decomposed through the first stage of the conventional raw meal pre-decomposition system. The feeding pipe of the top cyclone separator of the second row cyclone preheater or the third row cyclone preheater is fed into the feed port of the first row cyclone preheater of the carbon dioxide self-enrichment system. For raw materials containing high volatility sulfur The inferior raw meal, the sulfur impurities in the inferior raw meal in the form of organic sulfide, inorganic sulfide and other forms are in the top two-stage cyclone separator of the second column of cyclone preheater or the third column of cyclone preheater and the top of the communication The air inlet pipe of the two-stage cyclone separator is oxidized to generate SO ₂ gas, and the SO ₂ gas and low-sulfur inferior raw meal are gas-solid in the top cyclone separator of the second row cyclone preheater or the third row cyclone preheater Separation, SO ₂ gas is discharged with the flue gas, and the low-sulfur and inferior raw meal is fed into the feed port of the first row of cyclone preheaters of the carbon dioxide self-enrichment system, so as to ensure the feed inlet of the first row of cyclone preheaters. The raw meal has low sulfur content, thus ensuring low sulfur content in the low-temperature flue gas discharged from the first column of cyclone preheaters (SO ₂ concentration < 20mg/Nm ³ ), so that the CO ₂ purification system can save the desulfurization process or large The investment cost and operating cost of the desulfurization process are greatly reduced, and the operation stability of the CO ₂ purification system is improved.

The cement kiln system provided by the invention does not need to redesign the key firing equipment such as the rotary kiln and the cooler, greatly simplifies the technological process and reduces the transformation cost.

The cement kiln system provided by the present invention not only includes a carbon dioxide self-enriching first raw meal preheating and pre-decomposition system, but also includes a conventional second raw meal preheating and pre-decomposition system. When the concentration of carbon dioxide gas is used, only the conventional second raw meal preheating and pre-decomposition system is used to cooperate with the smoke chamber, rotary kiln, cooler, fan and other components to convert the raw meal into cement clinker, and discharge the raw meal containing low concentration (30%). Left and right) the flue gas of carbon dioxide gas, when it is necessary to capture high-concentration carbon dioxide gas from the flue gas, the carbon dioxide self-enriched first raw meal preheating pre-decomposition system and the conventional second raw meal preheating and pre-decomposition system Put into use together, the first raw meal preheating and pre-decomposition system discharges flue gas containing high concentration (above 70%) carbon dioxide gas, and the second raw meal preheating and pre-decomposition system discharges flue gas containing low concentration (about 30%) carbon dioxide gas gas, which can meet a variety of needs.

The first raw meal preheating and pre-decomposition system of the present invention and the conventional second raw meal pre-heating and pre-decomposing system are set relatively independently, and the first raw meal pre-heating and pre-decomposing system operates stably to the second raw meal pre-heating and pre-decomposing system Impact can be minimized. When the operation of the first raw meal preheating and predecomposition system fails, the second raw meal preheating and predecomposing system stops feeding raw meal to the first raw meal preheating and predecomposing system, and then the bottom of the first preheating furnace is connected The valve on the emergency discharge pipe of the first raw meal preheating and pre-decomposition system is opened to discharge the material in the first raw meal preheating and pre-decomposition system into the smoke chamber, thereby eliminating the potential safety hazard caused by the operation failure of the first raw meal pre-heating and pre-decomposition system. After the unloading is completed, the on-line maintenance of the first raw meal preheating and pre-decomposition system can be realized, and the stable operation of the second raw meal preheating and pre-decomposition system is not affected at this time. After the overhaul of the first raw meal preheating and pre-decomposition system is completed, the valve on the emergency discharge pipe connected to the bottom of the first precalciner can be closed. The feed pipe enters the smoke chamber, and the first raw meal preheating and pre-decomposition system is put into normal operation.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

Figure 1 is a schematic structural diagram of a cement kiln system suitable for high volatility sulfur raw materials;

Figure 2 is a schematic structural diagram of a cement kiln system suitable for low volatility sulfur raw materials;

Among them, 1-smoke chamber, 2-rotary kiln, 201-first burner, 3-cooler, 4-fan, 5-pre-combustion furnace, 501-combustion medium inlet, 502-second burner, 6-th 1 calciner, 601-third burner, 602-first raw meal inlet, 603-second raw meal inlet, 604-first air outlet pipe, 7-emergency discharge pipe, 801-first cyclone separator, 802-second cyclone, 803-third cyclone, 804-fourth cyclone, 805-fifth cyclone, 806-sixth cyclone, 807-seventh cyclone, 808- Eighth cyclone, 809-ninth cyclone, 8010-tenth cyclone, 8011-eleventh cyclone, 8012-twelfth cyclone, 8013-thirteenth cyclone, 8014 - Fourteenth cyclone, 8015 - Fifteenth cyclone, 901 - First exhaust pipe, 902 - Second exhaust pipe, 903 - Third exhaust pipe, 101 - First intake pipe, 102 - 2nd air inlet duct, 103- 3rd air inlet duct, 104- 4th air inlet duct, 105- 5th air inlet duct, 106- 6th air inlet duct, 107- 7th air inlet duct, 108- 1st air inlet duct Eighth intake duct, 109-ninth intake duct, 1010-tenth intake duct, 1011- eleventh intake duct, 1012-twelfth intake duct, 1101-first branch duct, 1102-th Second branch pipeline, 1103-third branch pipeline, 1104-fourth branch pipeline, 1105-fifth branch pipeline, 1106-sixth branch pipeline, 1201-first communication pipeline, 1202-second communication pipeline , 1203 - the third communication pipe, 13 - the second decomposition furnace, 1301 - the fourth burner, 1302 - the third raw meal inlet, 1303 - the fourth raw meal inlet, 1304 - the fifth raw meal inlet, 1305 - the sixth Raw meal inlet, 1306-second air outlet pipe, 1401-first material distribution valve, 1402-second material distribution valve, 1403-third material distribution valve.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Example 1

As shown in Figure 1, it is a cement kiln system suitable for high-volatile sulfur raw materials, including a smoke chamber 1, a rotary kiln 2, a cooler 3, a fan 4, a first raw meal preheating and pre-decomposition system, and a second raw meal preheating system. Thermal pre-decomposition system, the first raw meal pre-heating and pre-decomposition system is a carbon dioxide self-concentration system, and the second raw-meal pre-heating and pre-decomposition system is a conventional raw meal pre-heating and pre-decomposing system. It should be noted that the first The number of the raw meal preheating and pre-decomposition system and the number of the second raw meal preheating and pre-decomposition system is only for illustration, and those skilled in the art can set it according to actual needs. The cooler 3 can be a grate cooler, or a single For a drum cooler or a multi-drum cooler, the fan 4 can be a combination of existing multiple fans.

The first raw meal preheating and predecomposing system and the second raw meal preheating and predecomposing system are respectively communicated with the smoke chamber 1, the rotary kiln 2 is provided with a first burner 201, the tail of the rotary kiln 2 is communicated with the smoke chamber 1, and the rotary kiln The head of 2 communicates with the cooler 1 .

The first raw meal preheating and pre-decomposition system includes a pre-combustion furnace 5 , a first decomposition furnace 6 , a first row of cyclone preheaters, a first conveying pipeline assembly and an emergency discharge pipe 7 .

The side wall of the above-mentioned pre-combustion furnace 5 is provided with a combustion-supporting medium inlet 501, and the combustion-supporting medium can be selected from pure oxygen gas, and the pure oxygen gas can be purchased or made from an air separation device; the top of the pre-combustion furnace 5 is provided with a second burner 502, and the The bottom of the furnace 5 communicates with the cone of the first decomposition furnace 6;

The second burner 502 on the top of the pre-combustion furnace 5 adopts a multi-channel burner with an oil gun channel. When the first raw meal preheating and pre-decomposition system is just put into operation, the oil gun is used to ignite, and the temperature in the pre-combustion furnace is stabilized to After 600-700℃, switch to fuel combustion, and the fuel can be solid fuel, liquid fuel or gas fuel.

A third burner 601 is arranged on the above-mentioned first calcining furnace 6, a first row of raw meal inlets is set on the side wall of the first calcining furnace 6, and a first air outlet pipe 604 is set at the top of the first calcining furnace 6. It should be noted that, The first air outlet duct 604 can also be arranged on the side of the first decomposition furnace 6;

In order to regulate the temperature field distribution in the first calcining furnace 6, the first row of raw meal inlets can be set to multiple, and those skilled in the art can set them according to actual needs. The figure shows that the first row of raw meal inlets includes the first raw meal inlet. 602 and the second raw meal inlet 603.

The air inlet of the bottom cyclone separator of the above-mentioned first row of cyclone preheaters is connected to the first air outlet pipe of the first decomposition furnace 6, and the air outlet of the top cyclone separator of the first row of cyclone preheaters discharges the first low-temperature smoke. The temperature range of the first low-temperature flue gas is about 320-450 ℃; the first low-temperature flue gas contains high-concentration carbon dioxide gas, the carbon dioxide concentration in the low-temperature flue gas is higher than 70%, and the SO ₂ concentration is less than 20mg/Nm ³ ;

The feed port of the top cyclone separator of the first row of cyclone preheaters is used for raw material feeding, and the discharge port of the bottom cyclone separator of the first row of cyclone preheaters is connected to the smoke chamber.

Specifically, the figure shows that the first row of cyclone preheaters includes a first cyclone separator 801, a second cyclone separator 802, a third cyclone separator 803, and a fourth cyclone separator 804 that are communicated in sequence.

The top of the first cyclone separator 801 is provided with a first air outlet, and the first air outlet is communicated with the first exhaust pipe 901. The first exhaust pipe 901 is used to discharge the above-mentioned first low-temperature flue gas. The top side is communicated with the first air inlet pipe 101 , and the bottom end of the first cyclone separator 801 is communicated with the second air inlet pipe 102 .

The top of the second cyclone separator 802 is communicated with the first air inlet pipe 101, and the top side of the second cyclone separator 802 is communicated with the second air inlet pipe 102. A feed port is used for raw material feeding, and the bottom end of the second cyclone separator 802 is communicated with the third air inlet pipe 103 .

The top end of the third cyclone separator 803 communicates with the second air inlet pipe 102, the top side of the third cyclone separator 803 communicates with the third air inlet pipe 103, and the feeding pipe at the bottom end of the third cyclone separator 803 passes through the first air inlet pipe 103. The material distribution valve 1401 communicates with the raw material inlet of the first row, that is, the feeding pipe at the bottom of the third cyclone 803 communicates with the above-mentioned first raw material inlet 602 and second raw material inlet 603 through the first material distribution valve 1401 .

The top of the fourth cyclone separator 804 is communicated with the third air inlet pipe 103, the top side of the fourth cyclone separator 804 is provided with a first air inlet, and the first air inlet is connected to the first air inlet of the first decomposition furnace through the first communication pipe 1201. The air outlet pipe 604 communicates with each other, the bottom end of the fourth cyclone separator 804 is provided with a first discharge port, and the first discharge port is communicated with the smoke chamber 1 .

The above-mentioned first conveying pipeline assembly includes a first branch pipeline 1101, a second branch pipeline 1102 and a third branch pipeline 1103. The first branch pipeline 1101, the second branch pipeline 1102 and the third branch pipeline 1103 are arranged on valve;

The air inlets of the first branch pipe 1101, the second branch pipe 1102 and the third branch pipe 1103 communicate with the air outlet of the first exhaust pipe 901;

The exhaust port of the first branch pipe 1101 is sequentially connected with the cooling equipment, the dust removal equipment, and the carbon dioxide purification system. Preferably, the carbon dioxide in the part of the flue gas can be purified to obtain a food-grade or industrial product with a concentration greater than 99.9% for resource utilization. grade CO ₂ or dry ice to meet the domestic market demand for traditional food grade or industrial grade carbon dioxide products;

Due to pure oxygen combustion in the first calcining furnace 6, the concentration of CO ₂ in the flue gas is relatively high, resulting in an increase in the partial pressure of CO ₂ in the first calcining furnace 6, and the decomposition rate of raw meal is greatly reduced. For a comparable raw meal decomposition rate, it is necessary to increase the temperature in the first decomposition furnace 6 by about 100°C, which will easily lead to high temperature crusting on the first air outlet pipe 604 of the first decomposition furnace 6 and the cone of the fourth cyclone 804 . In this embodiment, the exhaust port of the second branch pipe 1102 is communicated with the first air outlet pipe of the first calcining furnace 6, and this part of the flue gas is used as a cooling medium to pass through the first air outlet duct of the first calcining furnace 6. The high temperature flue gas is cooled to prevent the problem of high temperature crusting and clogging of the first air outlet pipe 604 of the first precalciner 6 and the conical part of the fourth cyclone separator 804 .

The exhaust port of the third branch pipe 1103 is communicated with the combustion-supporting medium inlet 501 , and this part of the flue gas is mixed with the combustion-supporting medium (such as pure oxygen) entering the combustion-supporting medium inlet 501 , and is used as a mixed combustion-supporting medium for the combustion-supporting medium entering from the top of the pre-combustion furnace 5 . fuel combustion.

One end of the above-mentioned emergency discharge pipe 7 is communicated with the bottom of the first decomposition furnace 6, and the other end is communicated with the smoke chamber 1. The emergency discharge pipe 7 is provided with a valve, and the emergency discharge pipe 7 is provided with the following functions: when the system is suddenly powered off Or when other faults occur, the valve on the emergency discharge pipe 7 is opened, and the hot material in the first calciner 6 is discharged into the smoke chamber 1 through the emergency discharge pipe 7 to ensure the safety of the system.

The above-mentioned second raw meal preheating and pre-decomposition system includes a second decomposition furnace 13, a second row of cyclone preheaters and a third row of cyclone preheaters. It should be noted that the cyclone preheater in the second raw meal preheating and predecomposition system The number of rows of the heaters is only for illustration, and can be set by those skilled in the art according to actual needs.

A fourth burner 1301 is arranged on the second calcining furnace 13, a second air outlet duct 1306 is set on the second calcining furnace 13, and a second row of raw meal inlets and a third row of raw meal inlets are provided on the side wall of the second calciner 13, The bottom of the second calcining furnace 13 is communicated with the smoke chamber 1. In order to regulate the temperature field distribution in the second calcining furnace 13, the second row of raw meal inlets and the third row of raw meal inlets can be set in multiple numbers. The second row of raw meal inlets includes a third raw meal inlet 1302 and a fourth raw meal inlet 1303, and the third row of raw meal inlets includes a fifth raw meal inlet 1304 and a sixth raw meal inlet 1305. It should be noted that the schematic diagram in the figure The second row of raw meal inlets and the third row of raw meal inlets are only for illustration, and the second row of raw meal inlets and the third row of raw meal inlets of the second raw meal preheating and pre-decomposition system in this embodiment include but are not limited to these raw meal inlets. material inlet;

The air inlet of the bottom cyclone separator of the second row of cyclone preheaters is connected to the second air outlet pipe of the second decomposition furnace, and the air outlet of the top cyclone separator of the second row of cyclone preheaters discharges the second low-temperature flue gas , the temperature of the second low temperature flue gas is about 280-400 ℃, the second low temperature flue gas contains low concentration carbon dioxide gas, and the concentration of carbon dioxide gas is about 30%;

The feed port of the top cyclone separator of the second row of cyclone preheaters is used for raw material feeding, and the discharge port of the bottom cyclone separator of the second row of cyclone preheaters is connected to the smoke chamber;

The feeding pipe of the top cyclone separator of the second row of cyclone preheaters communicates with the feed port of the top cyclone separator of the first row of cyclone preheaters.

The number of stages of the second row of cyclone preheaters is preferably 3-7. The figure shows that the second row of cyclone preheaters includes a sixth cyclone separator 806, a seventh cyclone separator 807, and an eighth cyclone separator that are connected in sequence. 808, ninth cyclone 809 and tenth cyclone 8010.

The top of the sixth cyclone separator 806 is provided with a second air outlet, and the second air outlet is communicated with the second exhaust pipe 902 for discharging the above-mentioned second low-temperature flue gas. The top side of the sixth cyclone separator 806 is connected to the fifth inlet. The air duct 105 is connected, and the feeding pipe of the sixth cyclone separator 806 is provided with a fourth material distribution valve 1404. The spiral reamer is communicated with the first feeding port opened on the first air inlet pipe 101 of the above-mentioned first row of cyclone preheaters.

The top of the seventh cyclone separator 807 is communicated with the fifth air inlet pipe 105, and the fifth air inlet pipe 105 is provided with a second feeding port, and the second feeding port is used for raw material feeding. The top side is communicated with the sixth air inlet pipe 106 , and the bottom end of the seventh cyclone separator 807 is communicated with the seventh air inlet pipe 107 .

The top of the eighth cyclone separator 808 is communicated with the sixth air inlet duct 106, the top side of the eighth cyclone separator 808 is communicated with the seventh air inlet duct 107, and the bottom end of the eighth cyclone separator 808 is communicated with the eighth air inlet duct 108 Connected.

The top of the ninth cyclone separator 809 is communicated with the seventh air inlet pipe 107, the top side of the ninth cyclone separator 809 is communicated with the eighth air inlet pipe 108, and the feeding pipe at the bottom end of the ninth cyclone separator 809 passes through the second branch. The feed valve 1402 is communicated with the raw meal inlet of the second row, that is, the feed pipe at the bottom of the ninth cyclone 809 is communicated with the third raw meal inlet 1302 and the fourth raw meal inlet 1303 through the second feed valve 1402, respectively.

The top of the tenth cyclone separator 8010 is communicated with the eighth air inlet pipe 108, and the top side of the tenth cyclone separator 8010 is provided with a second air inlet. The two air outlet pipes 1306 are connected, and the bottom end of the tenth cyclone separator 8010 is provided with a second discharge port, and the second discharge port is communicated with the smoke chamber 1 .

Preferably, the exhaust port of the second exhaust pipe 902 is communicated with the intake port of the flue gas waste heat utilization system, so as to facilitate the utilization of waste heat of the flue gas discharged from the second row of cyclone preheaters.

The air inlet of the above-mentioned third row of cyclone preheaters is connected to the second air outlet pipe of the second decomposition furnace, and the air outlet of the third row of cyclone preheaters discharges the third low-temperature flue gas, and the temperature of the third low-temperature flue gas is 280- about 400℃; the third low-temperature flue gas contains low-concentration carbon dioxide gas, and the concentration of carbon dioxide gas is about 30%;

The feed port of the top cyclone separator of the third row of cyclone preheaters is used for raw material feeding, and the discharge port of the bottom end cyclone separator of the third row of cyclone preheaters is connected to the smoke chamber.

The number of stages of the third row of cyclone preheaters is preferably 3 to 7. The figure shows that the third row of cyclone preheaters includes an eleventh cyclone separator 8011, a twelfth cyclone separator 8012, and a thirteenth cyclone separator 8011, which are connected in sequence. Cyclone 8013, fourteenth cyclone 8014, and fifteenth cyclone 8015.

The top of the eleventh cyclone separator 8011 is provided with a third air outlet, and the third air outlet communicates with the third exhaust pipe 903 for discharging the third low-temperature flue gas. The top side of the eleventh cyclone separator 8011 is connected to the third air outlet. The ninth air inlet pipe 109 is in communication, and the bottom end of the eleventh cyclone separator 8011 is in communication with the tenth air inlet pipe 1010;

The top of the twelfth cyclone 8012 is communicated with the ninth air inlet pipe 109, and the ninth air inlet pipe 109 is provided with a third feeding port, the third feeding port is used for raw material feeding, and the twelfth cyclone separator The top side of the 8012 is communicated with the tenth air inlet duct 1010, and the bottom end of the twelfth cyclone 8012 is communicated with the eleventh air inlet duct 1011;

The top end of the thirteenth cyclone separator 8013 is communicated with the tenth air inlet pipe 1010, the top side of the thirteenth cyclone separator 8013 is communicated with the eleventh air inlet pipe 1011, and the bottom end of the thirteenth cyclone separator 8013 is communicated with the eleventh air inlet pipe 1011. The twelve air inlet pipes 1012 are connected;

The top of the fourteenth cyclone separator 8014 is communicated with the eleventh air inlet pipe 1011, the top side of the fourteenth cyclone separator 8014 is communicated with the twelfth air inlet pipe 1012, and the bottom end of the fourteenth cyclone separator 8014 is blanked. The pipe is communicated with the raw material inlet of the third row through the third material distribution valve 1403, that is, the feeding pipe at the bottom of the fourteenth cyclone separator 8014 is connected to the fifth raw material inlet 1304 and the sixth raw material through the third material distribution valve 1403. The inlet 1305 is connected;

The top of the fifteenth cyclone separator 8015 is communicated with the twelfth air inlet pipe 1012, the top side of the fifteenth cyclone separator 8015 is provided with a third air inlet, and the third air inlet is connected to the second decomposition furnace through the third communication pipe 1203. The second air outlet pipe 1306 at the top of 13 is connected, and the bottom end of the fifteenth cyclone separator 8015 is provided with a third discharge port, and the third discharge port is communicated with the smoke chamber 1 .

Preferably, the exhaust port of the third exhaust pipe 903 is communicated with the intake port of the flue gas waste heat utilization system, so as to facilitate the utilization of waste heat of the flue gas discharged from the third row of cyclone preheaters.

As a preferred embodiment, the above-mentioned cement kiln system further includes a second conveying pipeline assembly, and the second conveying pipeline assembly includes a fourth branch pipeline 1104, a fifth branch pipeline 1105 and a sixth branch pipeline 1106;

The air inlets of the fourth branch pipe 1104, the fifth branch pipe 1105 and the sixth branch pipe 1106 communicate with the air outlet of the cooler 3;

The air outlet of the fourth branch pipe 1104 is communicated with the air inlet of the flue gas waste heat system, the air outlet of the fifth branch pipe 1105 is communicated with the rotary kiln 2, and the sixth branch pipe 1106 is communicated with the second decomposition furnace 13. .

It should be noted that: the above-mentioned fourth material distribution valve 1404 is arranged at the bottom end of the top cyclone separator of the second row of cyclone preheaters (ie, the sixth cyclone separator in the figure) is only for illustration, and those skilled in the art are The fourth distributing valve 1404 can also be set at the seventh cyclone separator of the second row of cyclone preheaters or the feed pipe of the eighth cyclone separator or the top cyclone separator of the third row of cyclone preheaters (ie, Fig. In the eleventh cyclone separator), the twelfth cyclone separator or the feed pipe of the thirteenth cyclone separator, preferably, the fourth distribution valve 1404 is arranged in the sixth cyclone separator of the second row of cyclone preheaters The purpose is to reduce the heat consumption of the carbon dioxide self-enrichment system (the first preheating and pre-decomposition system), because if the raw meal is from the second column If the feeding pipe of the cyclone preheater or the non-top cyclone separator of the third row of cyclone preheater enters the first preheating and pre-decomposition system, the outlet flue gas temperature of the first pre-heating and pre-decomposition system should be increased on the existing basis Dozens or even hundreds of degrees Celsius, since cooling and dust removal treatment is required before entering the subsequent flue gas purification system, this will also increase the specifications and investment of cooling equipment. A preheating precalciner system is the most cost-effective location.

The process of preparing cement clinker using the above-mentioned cement kiln system suitable for high volatility sulfur raw materials is as follows:

When it is necessary to capture high concentrations of carbon dioxide from the flue gas of a cement kiln system, the cement kiln system is a precalciner kiln with self-concentration of carbon dioxide:

Preheating the pre-decomposition system for the first raw meal

I-1 The raw meal is passed from the feed pipe of the top cyclone separator of the second row of cyclone preheaters (or the top cyclone separator of the third row of cyclone preheaters) through the fourth distribution valve 1404 through the screw hinge with metering The knives are fed into the first row of cyclone preheaters from the first feed port, and then enter the first decomposition furnace 6 through multiple heat exchanges and gas-solid separation. The amount of raw meal fed into the first row of cyclone preheaters varies from The content of carbon dioxide captured in the flue gas of the cement kiln system can be adjusted flexibly, and the preferred ratio of the raw meal fed to the first row of cyclone preheaters is 0-90%. When the ratio is 0%, there is no need to feed raw meal to the first raw meal preheating and pre-decomposition system.

1-2 Combustion-supporting medium enters the pre-combustion furnace 5 from the combustion-supporting medium inlet 501 for combustion of the fuel entering the pre-combustion furnace 5 from the top of the pre-combustion furnace 5, and the combustion products enter the first decomposition furnace 6 from the bottom of the pre-combustion furnace 5 , the first decomposition furnace 6 is pure oxygen combustion, and a large amount of heat released by the combustion is used for the endothermic decomposition of the raw meal in the first decomposition furnace 6 to obtain hot raw meal and generate a large amount of flue gas.

1-3 The hot raw meal and the flue gas generated in the first calcining furnace 6 leave the first calcining furnace 6, and enter the first row of cyclone preheaters through the first air inlet, so that the hot raw meal and the flue gas are separated, as follows:

The flue gas generated in the first decomposition furnace 6 moves upward through the first row of cyclone preheaters, and contacts the raw meal fed into the first row of cyclone preheaters to achieve heat exchange with the raw meal, and then passes through the first air outlet. Exhaust through the first exhaust pipe 901 to obtain low-temperature flue gas, the carbon dioxide concentration in the low-temperature flue gas is more than 70%, and the SO ₂ concentration is less than 20 mg/Nm ³ ;

The low-temperature flue gas enters the first branch pipe 1101, the second branch pipe 1102 and the third branch pipe 1103 respectively. The road pipe 1102 enters the first air outlet pipe of the first decomposition furnace 6, and enters the combustion-supporting medium inlet 501 through the third branch pipe 1103;

The hot raw meal produced in the first decomposition furnace 6 moves downward through the first discharge port of the first row of cyclone preheaters and enters the smoke chamber.

Preheating the pre-decomposition system for the second raw meal

II-1 The raw meal is fed into the second row of cyclone preheaters through the second feeding port and the third row of cyclone preheaters through the third feeding port respectively from the feeding device through the elevator, and then enters the second decomposition furnace within 13.

II-2 The fuel combustion in the second decomposition furnace 13 generates a large amount of heat, which is used for endothermic decomposition of the raw meal in the second decomposition furnace 13 to obtain hot raw meal and generate a large amount of flue gas.

II-3 The hot raw meal and flue gas generated in the second calcining furnace 13 leave the second calcining furnace 13 and enter the second row of cyclone preheaters through the second air inlet and into the third row of cyclone preheaters through the third air inlet , so that the hot raw meal is separated from the flue gas, as follows:

The flue gas generated in the second decomposition furnace 13 moves upward through the second row of cyclone preheaters and the third row of cyclone preheaters, respectively, and is fed into the second row of cyclone preheaters and the third row of cyclone preheaters. The raw meal is in contact with the raw meal to achieve heat exchange with the raw meal, and is then discharged through the second exhaust pipe 902 through the second air outlet and through the third exhaust pipe 903 through the third air outlet to obtain low-temperature flue gas, carbon dioxide in the low-temperature flue gas. The concentration is about 30%;

The low-temperature flue gas enters the flue gas waste heat utilization system for power generation, enters the raw meal mill to dry the raw meal, and then is processed by the flue gas treatment system and then discharged into the atmosphere;

The hot raw meal produced in the second decomposition furnace 13 moves downward through the second outlet of the second row of cyclone preheaters and the third outlet of the third row of cyclone preheaters, respectively, and enters the smoke chamber.

For smoke chamber 1, rotary kiln 2, fan 4 and cooler 3

III The hot raw meal generated in the first precalciner 6 and the hot raw meal generated in the second precalciner 13 enter the rotary kiln 2 through the smoke chamber 1, and are calcined in the rotary kiln 2 to become cement clinker, and the fuel in the rotary kiln is burned The kiln gas is generated, and the kiln gas passes through the smoke chamber 1 and the second decomposition furnace 13 in turn, and then enters the second air outlet of the second row of cyclone preheaters and the third outlet of the third row of cyclone preheaters from the second decomposition furnace 13 respectively. The tuyere is then discharged as low-temperature flue gas through the second exhaust pipe 902 and the third exhaust pipe 903 respectively;

The cement clinker enters the cooler 3 from the rotary kiln 2, and the air in the fan 4 enters the cooler 1 to exchange heat with the cement clinker, cooling the cement clinker to 65°C + ambient temperature;

The heat-exchanged air enters the fourth branch pipe 1104, the fifth branch pipe 1105 and the sixth branch pipe 1106 respectively, and enters the flue gas waste heat utilization system through the fourth branch pipe 1104 for power generation or other operations, and then passes through the chimney. It is discharged into the atmosphere, enters the rotary kiln 2 as secondary air through the fifth branch pipe 1105 for fuel combustion, and enters the second decomposition furnace 13 as tertiary air through the sixth branch pipe 1106 for fuel combustion. Preferably, the fourth The air temperature in the branch pipe 1104 is 250-450°C, the air temperature in the fifth branch pipe 1105 is 900-1200°C, and the air temperature in the sixth branch pipe 1106 is 800-1000°C.

When it is not necessary to capture high-concentration carbon dioxide gas from the flue gas of the cement kiln system, the first raw meal preheating and pre-decomposition system does not need to work, and only the second raw meal preheating and pre-decomposition system, smoke chamber 1, rotary kiln 2, Fan 4, cooler 3 and other components work, and the work flow is the same as the above-mentioned second raw meal preheating and pre-decomposition system, smoke chamber 1, rotary kiln 2, fan 4, cooler 3 and other components. It is not repeated here.

Example 2

Figure 2 shows a cement kiln system suitable for low-volatile sulfur raw materials, which differs from the cement kiln system suitable for high-volatile sulfur raw materials in Figure 1, mainly in the following two points:

Difference 1: The number of stages of the first column of cyclone preheaters is different;

2 shows that the first row of cyclone preheaters includes a first cyclone separator 801 , a second cyclone separator 802 , a third cyclone separator 803 , a fourth cyclone separator 804 and a fifth cyclone separator 805 that are communicated in sequence.

The top of the first cyclone separator 801 is provided with a first air outlet, and the first air outlet is communicated with the first exhaust pipe 901. The first exhaust pipe 901 is used to discharge the above-mentioned first low-temperature flue gas. The top side is communicated with the first air inlet pipe 101 , and the bottom end of the first cyclone separator 801 is communicated with the second air inlet pipe 102 .

The top of the second cyclone separator 802 is communicated with the first air inlet pipe 101, and the top side of the second cyclone separator 802 is communicated with the second air inlet pipe 102. A feed port is used for raw material feeding, and the bottom end of the second cyclone separator 802 is communicated with the third air inlet pipe 103 .

The top end of the third cyclone separator 803 is communicated with the second air inlet pipe 102, the top side of the third cyclone separator 803 is communicated with the third air inlet pipe 103, and the bottom end of the third cyclone separator 803 is communicated with the fourth air inlet pipe 104 Connected.

The top of the fourth cyclone separator 804 is communicated with the third air inlet pipe 103, the top side of the fourth cyclone separator is communicated with the fourth air inlet pipe 104, and the feeding pipe at the bottom of the fourth cyclone separator 804 passes through the first material distribution. The valve 1401 communicates with the raw meal inlet of the first row, that is, the feeding pipe at the bottom of the fourth cyclone 804 communicates with the above-mentioned first raw meal inlet 602 and second raw meal inlet 603 through the first material distribution valve 1402 .

The top of the fifth cyclone separator 805 is communicated with the fourth air inlet pipe 104, and the top side of the fifth cyclone separator 805 is provided with a first air inlet. The air outlet pipe 604 communicates with each other, the bottom end of the fifth cyclone separator 805 is provided with a first discharge port, and the first discharge port is communicated with the smoke chamber 1 .

It should be noted that although the number of stages of the first row of cyclone preheaters in the cement kiln system suitable for low-volatile sulfur raw materials in Figure 2 and the cement kiln system suitable for high-volatile sulfur raw materials in Figure 1 is different, the figure only For illustration, the number of stages of the first row of cyclone preheaters may also be the same for a cement kiln system suitable for low volatility sulfur feedstocks and a cement kiln system suitable for high volatility sulfur feedstocks.

Difference 2: The feeding pipe of the top cyclone separator of the second row of cyclone preheaters does not need to communicate with the feed port of the top cyclone separator of the first row of cyclone preheaters.

The same points about the structure of the cement kiln system will not be repeated here.

The process of preparing cement clinker using the above-mentioned cement kiln system suitable for low-volatile sulfur raw materials is basically the same as the above-mentioned process of preparing cement clinker using the above-mentioned cement kiln system suitable for high-volatile sulfur raw materials. The feeding pipe of the top cyclone separator of the row cyclone preheater (or the top cyclone separator of the third row cyclone preheater) is fed into the first row of cyclone preheaters, and the rest of the process is the same as that suitable for high volatility sulfur raw materials. The process of preparing cement clinker in the cement kiln system is the same, and will not be repeated here.

The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art can still modify or equivalently replace the specific embodiments of the present invention. , any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention are all within the protection scope of the claims of the present invention for which the application is pending.

Claims (13)

1. A cement kiln system is characterized in that it includes a smoke chamber, a rotary kiln and a cooler connected in sequence, a first burner is arranged on the rotary kiln, and the cement kiln system further includes a first raw meal preheating and pre-decomposition system and a second raw material preheating and pre-decomposition system. Two raw meal preheating and predecomposition systems, the first raw meal preheating and predecomposing system is a carbon dioxide self-enrichment system, the second raw meal preheating and predecomposing system is a conventional raw meal preheating and predecomposing system, and the The first raw meal preheating and pre-decomposition system includes a pre-combustion furnace, a first decomposition furnace and a first row of cyclone preheaters;

   A combustion-supporting medium inlet is set on the pre-combustion furnace, a second burner is arranged on the pre-combustion furnace, and the bottom of the pre-combustion furnace is communicated with the cone of the first decomposition furnace;

   A third burner is arranged on the first calcining furnace, and a first row of raw meal inlets is set on the first calcining furnace;

   The air inlet of the bottom cyclone separator of the first row of cyclone preheaters is connected to the air outlet pipe of the first decomposition furnace, and the air outlet of the top cyclone separator of the first row of cyclone preheaters discharges low-temperature smoke The feed port of the top cyclone separator of the first row of cyclone preheaters is used for raw material feeding, and the discharge port of the bottom cyclone separator of the first row of cyclone preheaters is connected to the smoke room;

   The second raw meal preheating and pre-decomposition system is communicated with the smoke chamber.
2. The cement kiln system according to claim 1, wherein,

   The second raw meal preheating and pre-decomposition system includes a second decomposition furnace and a second row of cyclone preheaters;

   A fourth burner is arranged on the second calcining furnace, and a second row of raw meal inlets is set on the second calcining furnace;

   The air inlet of the bottom cyclone separator of the second row of cyclone preheaters is connected to the air outlet pipe of the second decomposition furnace, and the air outlet of the top cyclone separator of the second row of cyclone preheaters discharges low-temperature smoke gas;

   The feed port of the top cyclone separator of the second row of cyclone preheaters is used for raw material feeding, and the discharge port of the bottom end cyclone separator of the second row of cyclone preheaters is connected to the smoke chamber.
3. The cement kiln system according to claim 2, wherein the second raw meal preheating and pre-decomposition system further comprises a third row of cyclone preheaters, and a third row of raw meal inlets is provided on the second precalciner ;

   The air inlet of the bottom cyclone separator of the third row of cyclone preheaters is connected to the air outlet pipe of the second decomposition furnace, and the air outlet of the top cyclone separator of the third row of cyclone preheaters discharges low-temperature smoke gas;

   The feed port of the top cyclone separator of the third row of cyclone preheaters is used for raw material feeding, and the discharge port of the bottom cyclone separator of the third row of cyclone preheaters is connected to the smoke chamber.
4. The cement kiln system according to claim 3, wherein the feeding pipe of the top cyclone separator of the second row of cyclone preheaters or the third row of cyclone preheaters and the first row of cyclone preheaters The feed port of the top cyclone separator is connected.
5. The cement kiln system according to claim 3, wherein the number of stages of the first row of cyclone preheaters is 3-7; the number of stages of the second row of cyclone preheaters is 3-7 , the number of stages of the third row of cyclone preheaters is 3-7.
6. The cement kiln system of claim 1, wherein the first row of raw meal inlets includes one or more raw meal inlets;

   A first material distribution valve is set at the feeding pipe of the penultimate second-stage cyclone separator from bottom to top of the first row of cyclone preheaters, and the first material distribution valve is connected to one of the raw meal inlets of the first row or multiple raw meal inlets.
7. The cement kiln system according to claim 1, wherein the first raw meal preheating and pre-decomposition system further comprises a first conveying pipe assembly, the first conveying pipe assembly comprising a first branch pipe, a second Branch pipelines and third branch pipelines;

   The air inlets of the first branch pipe, the second branch pipe and the third branch pipe are communicated with the air outlet of the top cyclone separator of the first row of cyclone preheaters;

   The exhaust port of the first branch pipe is communicated with the cooling equipment, the dust removal equipment, and the carbon dioxide purification system in sequence, and the exhaust port of the second branch pipe is communicated with the air outlet pipe of the first decomposition furnace. The exhaust port of the third branch pipeline is communicated with the combustion-supporting medium inlet.
8. The cement kiln system according to claim 1, wherein the first raw meal preheating and pre-decomposition system further comprises an emergency discharge pipe, one end of the emergency discharge pipe is connected to the bottom of the first precalciner The other end of the emergency discharge pipe is communicated with the smoke chamber.
9. The method for preparing cement clinker by adopting a cement kiln system is characterized in that, the method comprises the following steps:

   When the cement kiln system is a CO2 self-accumulating precalciner:

   The raw meal is fed into the second row of cyclone preheaters, the third row of cyclone preheaters and the first row of cyclone preheaters, and the raw meal and the flue gas undergo heat exchange and gas-solid separation in the cyclone preheater;

   The raw meal preheated by the first row of cyclone preheaters enters the first decomposition furnace, and the raw meal preheated by the second row of cyclone preheaters and the third row of cyclone preheaters enters the second decomposition furnace;

   The combustion-supporting medium enters the pre-combustion furnace from the combustion-supporting medium inlet of the pre-combustion furnace, and is used for the combustion of the fuel entering the pre-combustion furnace from the top of the pre-combustion furnace, and the combustion products enter the first decomposition furnace from the bottom of the pre-combustion furnace. The interior is pure oxygen combustion, and a large amount of heat released by the combustion is used for the endothermic decomposition of the raw meal in the first decomposition furnace to obtain hot raw meal and generate a large amount of flue gas. The flue gas generated in the first decomposition furnace enters the first column of cyclone preheater. The heat exchange with the raw meal in the heater becomes low-temperature flue gas. The low-temperature flue gas is discharged through the air outlet of the top cyclone separator of the first row of cyclone preheaters. The carbon dioxide concentration in the low-temperature flue gas is higher than 70%, and the SO ₂ concentration is less than 20mg. /Nm ³ , the enrichment amount of carbon dioxide gas can be adjusted by adjusting the amount of raw meal fed into the first row of cyclone preheaters;

   The raw meal in the second calciner is decomposed by endothermic heat to obtain hot raw meal, and a large amount of flue gas is generated. The flue gas in the second calciner enters the second row of cyclone preheaters and the third row of cyclone preheaters respectively. The heat exchange of raw meal becomes low-temperature flue gas. The low-temperature flue gas is discharged through the air outlet of the top cyclone separator of the second row of cyclone preheaters and the third row of cyclone preheaters respectively. The carbon dioxide concentration in the low-temperature flue gas is 25-35%. ;

   The hot raw materials generated in the first and second calciners enter the rotary kiln through the smoke chamber, and are calcined in the rotary kiln to form cement clinker. The fuel in the rotary kiln is burned to generate kiln gas, and the cement clinker is cooled from the outlet of the rotary kiln. The kiln gas enters the second row of cyclone preheaters and the third row of cyclone preheaters respectively through the smoke chamber and the second calciner, and passes through the second row of cyclone preheaters and the third row of cyclone preheaters. The air outlet of the top cyclone separator of the three-row cyclone preheater is discharged as low-temperature flue gas;

   When the cement kiln system is a conventional precalciner kiln, the first raw meal preheating and precalciner system stops working:

   The raw meal is fed into the second row of cyclone preheaters and the third row of cyclone preheaters respectively, and the raw meal exchanges heat with the flue gas in the cyclone preheater;

   The raw meal preheated by the second row of cyclone preheaters and the third row of cyclone preheaters enters the second decomposition furnace;

   The raw meal is endothermic and decomposed in the second calcining furnace to obtain hot raw meal, and a large amount of flue gas is generated. The heat exchange of the material becomes low-temperature flue gas, and the low-temperature flue gas is discharged through the air outlet of the top cyclone separator of the second row of cyclone preheaters and the third row of cyclone preheaters respectively, and the carbon dioxide concentration in the low-temperature flue gas is 25-35%;

   The hot raw meal enters the rotary kiln through the smoke chamber, and is calcined in the rotary kiln to form cement clinker. The fuel in the rotary kiln burns the kiln gas, and the cement clinker enters the cooler from the outlet of the rotary kiln, and exchanges heat with the air to obtain the cooled cement clinker. The kiln gas enters the second row of cyclone preheaters and the third row of cyclone preheaters through the smoke chamber and the second calciner in turn, and passes through the top cyclone separators of the second row of cyclone preheaters and the third row of cyclone preheaters. The air outlet is discharged as low temperature flue gas.
10. The method for preparing cement clinker according to claim 9, wherein the raw meal is fed into the second row of cyclone preheaters, the third row of cyclone preheaters and the first row of cyclone preheaters, and the raw In the cyclone preheater, the raw material undergoes heat exchange and gas-solid separation with the flue gas, which specifically includes: feeding the raw meal into the second row of cyclone preheaters, the third row of cyclone preheaters and the first row of cyclone preheaters, respectively. The raw meal undergoes heat exchange and gas-solid separation with the flue gas in the cyclone preheater.
11. The method for preparing cement clinker according to claim 9, wherein the raw meal is fed into the second row of cyclone preheaters, the third row of cyclone preheaters and the first row of cyclone preheaters, and the raw In the cyclone preheater, the raw material undergoes heat exchange and gas-solid separation with the flue gas, specifically including: feeding the raw meal into the second row of cyclone preheaters, the third row of cyclone preheaters, the second row of cyclone preheaters or The raw meal of the third row of cyclone preheaters is divided into two paths through the feeding pipe of the top cyclone separator, one raw meal enters the second row of cyclone preheaters or the third row of cyclone preheaters, and the other raw meal enters In the first row of cyclone preheaters, the raw meal exchanges heat with flue gas and separates gas and solid in the cyclone preheater.
12. The method for preparing cement clinker according to claim 9, wherein the low-temperature flue gas discharged from the air outlet of the top cyclone separator of the first row of cyclone preheaters is divided into three paths, and the low-temperature flue gas of the first line is divided into three paths. After cooling and dust removal, the gas enters the carbon dioxide purification system for purification. The second low-temperature flue gas is passed into the air outlet pipe of the first decomposition furnace, and the third low-temperature flue gas is mixed with pure oxygen produced by outsourcing or oxygen production system. It is passed into the pre-combustion furnace as a combustion-supporting medium.
13. The method for preparing cement clinker according to claim 9, wherein the bottom of the first precalciner is communicated with the smoke chamber through an emergency discharge pipe.

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