Staged combustion dry-process cement production process
By adopting graded combustion technology and multi-stage denitrification and denitrification methods in dry cement production, the problems of high NOx generation, high energy consumption and low raw material utilization in traditional dry cement production are solved, and the coordinated optimization of production and environmental protection and the reduction of energy consumption are achieved.
Patent Information
- Application Number
- CN202510305497.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-14
- Publication Date
- 2025-05-13
AI Technical Summary
In traditional dry cement production, the production volume of nitrogen oxide (NOx) during the combustion process is high, the exhaust gas treatment cost is large, and the coupling between the denitrification and denitrification processes and the production process is poor, resulting in increased energy consumption and low raw material utilization.
The graded combustion dry cement production process is adopted, including raw material pretreatment, graded combustion and clinker firing, clinker cooling, cement grinding and other steps. By setting a primary and secondary combustion zone in the rotary kiln, combining low-oxygen multi-point air distribution and denitrification and nitrogen removal methods, the NOx generation is reduced and the utilization rate of raw materials is improved.
Through the hierarchical combustion technology and multi-stage denitrification and denitrification agent administration system, the reduction of NOx generation, the coordinated optimization of production and environmental protection, the reduction of energy consumption, and the improvement of raw material utilization are achieved.
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Figure CN119977369A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a field, and in particular to a staged combustion dry cement production process. Background Art
[0002] Cement: Powdered hydraulic inorganic cementitious material. After adding water and stirring, it becomes a slurry, which can harden in the air or in water, and can firmly glue sand, stone and other materials together. It is widely used in the construction field.
[0003] Cement production has dry and wet production processes. The dry production process has the advantages of high thermal efficiency and low energy consumption, and it is gradually replacing the wet production process.
[0004] Traditional dry production usually includes several steps: raw material mining and crushing, raw material drying and grinding, preheating and decomposition, calcination (rotary kiln), cooling, clinker grinding, storage and packaging, etc.
[0005] Traditional dry process cement production has the following problems:
[0006] During combustion, nitrogen oxides (NO x ) The amount of gas generated is high and the cost of tail gas treatment is high;
[0007] The denitrification and denitrification processes are poorly coupled with the production process, resulting in increased energy consumption;
[0008] The utilization rate of raw materials is low and the proportion of solid waste such as construction waste is limited.
[0009] To this end, the present invention proposes a staged combustion dry process cement production process. Summary of the invention
[0010] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a staged combustion dry cement production process.
[0011] In order to achieve the above object, the present invention adopts the following technical solutions:
[0012] A staged combustion dry process cement production process comprises the following steps:
[0013] S1: Raw material pretreatment, crushing limestone, high silicon raw materials, construction waste, iron raw materials, and bituminous coal separately, and then mixing and homogenizing in a homogenizing pile;
[0014] S2: Gradual combustion and clinker burning, the mixed and homogenized raw materials are put into the rotary kiln for graded combustion to produce clinker;
[0015] S3: Clinker cooling: the clinker discharged from the kiln is rapidly cooled by a grate cooler;
[0016] S4: Cement grinding, mixing the clinker with gypsum and fly ash, and then grinding to obtain finished cement;
[0017] S5: The ground cement is stored in bulk silos or packed into bags by packaging machines.
[0018] Preferably: in the step S1, the mass ratio of the raw materials is: 70-80 parts of limestone, 5-10 parts of high-silicon raw materials, 10-15 parts of construction waste, 5-10 parts of iron raw materials, and 3-5 parts of bituminous coal.
[0019] Preferably: in the step S1, the particle size after crushing is less than 50 mm, and the moisture content of the mixture in the homogenization pile is less than 5%.
[0020] Preferably: in the step S2, the rotary kiln has a primary combustion zone located in the decomposition zone at the kiln tail and a secondary combustion zone located in the main combustion zone at the kiln head.
[0021] Preferably: the temperature of the primary combustion zone is 800-900 degrees Celsius, low-oxygen multi-point air distribution is adopted, and the oxygen content of the air distribution is less than 5%;
[0022] The temperature of the secondary combustion zone is 1450-1550 degrees Celsius.
[0023] Preferably: in the step S2, the combustion process also includes a denitrification and denitrification method.
[0024] Preferably: the implementation means of the denitrification and denitrification method include:
[0025] S21: Move the coal feeding point of the decomposition furnace to the top of the kiln tail smoke chamber or the cone of the decomposition furnace, and pyrolyze the coal powder in a low-oxygen environment to generate CO, CH4, and H2 reducing gases, which undergo redox reactions with NOx in the kiln to achieve initial denitrification;
[0026] S22: Add a five-stage outlet pipeline denitrification spray gun, ammonia water and compressed air required for atomization, which are drawn out from the original denitrification system control cabinet, and the control system remains unchanged;
[0027] S23: Use a four-stage discharge pipe for discharge, and add a distribution valve, a flash valve, a discharge pipe and a spreading device to the four-stage discharge pipe.
[0028] Preferably: in step S22, the concentration of aqueous ammonia is 8%-12%, and the flow rate is 0.7-0.9 L / t clinker.
[0029] Preferably, in the step S3, the rapid cooling temperature is less than 100°C.
[0030] Preferably: in the step S4, the proportions of the mixed components are: 70-75 parts of clinker, 4-5 parts of gypsum, 15-20 parts of fly ash, and the specific surface area after grinding is greater than 380m 2 / kg.
[0031] The beneficial effects of the present invention are:
[0032] 1. The present invention reduces NO through staged combustion technology x Generation, combined with multi-stage denitrification and denitrification agent addition system, realizes the coordinated optimization of production and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Figure 1 This is a process flow chart of the staged combustion dry process cement production proposed by the present invention. DETAILED DESCRIPTION
[0034] The technical solution of the present invention is further described in detail below in conjunction with specific implementation methods.
[0035] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense, for example, they can be fixedly connected or set, or detachably connected or set, or integrally connected or set. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0036] Embodiment 1:
[0037] A staged combustion dry process cement production process comprises the following steps:
[0038] S1: Raw material pretreatment, crushing limestone, high silicon raw materials, construction waste, iron raw materials, and bituminous coal separately, and then mixing and homogenizing in a homogenizing pile;
[0039] S2: Gradual combustion and clinker burning, the mixed and homogenized raw materials are put into the rotary kiln for graded combustion to produce clinker;
[0040] S3: Clinker cooling: the clinker discharged from the kiln is rapidly cooled by a grate cooler;
[0041] S4: Cement grinding, mixing the clinker with gypsum and fly ash, and then grinding to obtain finished cement;
[0042] S5: The ground cement is stored in bulk silos or packed into bags by packaging machines.
[0043] In the step S1, the mass ratio of the raw materials is: 70-80 parts of limestone, 5-10 parts of high-silicon raw materials, 10-15 parts of construction waste, 5-10 parts of iron raw materials, and 3-5 parts of bituminous coal.
[0044] In the step S1, the particle size after crushing is less than 50 mm, and the water content of the mixture in the homogenization pile is less than 5%.
[0045] In the step S2, the rotary kiln has a primary combustion zone located in the decomposition zone at the kiln tail and a secondary combustion zone located in the main combustion zone at the kiln head;
[0046] The temperature of the primary combustion zone is 800-900 degrees Celsius, and low-oxygen multi-point air distribution is adopted, and the oxygen content of the air distribution is less than 5%;
[0047] The temperature of the secondary combustion zone is 1450-1550 degrees Celsius.
[0048] In the step S3, the rapid cooling temperature is less than 100°C.
[0049] In the step S4, the proportions of the mixed parts are: 70-75 parts of clinker, 4-5 parts of gypsum, and 15-20 parts of fly ash. The specific surface area after grinding is greater than 380m 2 / kg.
[0050] Embodiment 2:
[0051] A staged combustion dry process cement production process comprises the following steps:
[0052] S1: Raw material pretreatment, crushing limestone, high silicon raw materials, construction waste, iron raw materials, and bituminous coal separately, and then mixing and homogenizing in a homogenizing pile;
[0053] S2: Gradual combustion and clinker burning, the mixed and homogenized raw materials are put into the rotary kiln for graded combustion to produce clinker;
[0054] S3: Clinker cooling: the clinker discharged from the kiln is rapidly cooled by a grate cooler;
[0055] S4: Cement grinding, mixing the clinker with gypsum and fly ash, and then grinding to obtain finished cement;
[0056] S5: The ground cement is stored in bulk silos or packed into bags by packaging machines.
[0057] In the step S1, the mass ratio of the raw materials is: 72 parts to 78 parts of limestone, 7 parts to 8 parts of high-silicon raw materials, 12 parts to 13 parts of construction waste, 7 parts to 8 parts of iron raw materials, and 3.5 parts to 4.5 parts of bituminous coal.
[0058] In the step S1, the particle size after crushing is less than 50 mm, and the water content of the mixture in the homogenization pile is less than 5%.
[0059] In the step S2, the rotary kiln has a primary combustion zone located in the decomposition zone at the kiln tail and a secondary combustion zone located in the main combustion zone at the kiln head;
[0060] The temperature of the primary combustion zone is 820-880 degrees Celsius, and low-oxygen multi-point air distribution is adopted, and the oxygen content of the air distribution is less than 5%;
[0061] The temperature of the secondary combustion zone is 1480-1520 degrees Celsius.
[0062] In the step S2, the combustion process also includes a denitrification and denitrification method.
[0063] In the step S3, the rapid cooling temperature is less than 100°C.
[0064] In the step S4, the proportions of the mixed parts are: 72.5 parts of clinker, 4.5 parts of gypsum, and 17.5 parts of fly ash. The specific surface area after grinding is greater than 380m 2 / kg.
[0065] Embodiment 3:
[0066] A staged combustion dry process cement production process comprises the following steps:
[0067] S1: Raw material pretreatment, crushing limestone, high silicon raw materials, construction waste, iron raw materials, and bituminous coal separately, and then mixing and homogenizing in a homogenizing pile;
[0068] S2: Gradual combustion and clinker burning, the mixed and homogenized raw materials are put into the rotary kiln for graded combustion to produce clinker;
[0069] S3: Clinker cooling: the clinker discharged from the kiln is rapidly cooled by a grate cooler;
[0070] S4: Cement grinding, mixing the clinker with gypsum and fly ash, and then grinding to obtain finished cement;
[0071] S5: The ground cement is stored in bulk silos or packed into bags by packaging machines.
[0072] In the step S1, the mass ratio of the raw materials is: 75 parts of limestone, 7.5 parts of high-silicon raw materials, 12.5 parts of construction waste, 7.5 parts of iron raw materials, and 4 parts of bituminous coal.
[0073] In the step S1, the particle size after crushing is less than 50 mm, and the water content of the mixture in the homogenization pile is less than 5%.
[0074] In the step S2, the rotary kiln has a primary combustion zone located in the decomposition zone at the kiln tail and a secondary combustion zone located in the main combustion zone at the kiln head;
[0075] The temperature of the primary combustion zone is 850 degrees Celsius, and low-oxygen multi-point air distribution is adopted, and the oxygen content of the air distribution is less than 5%;
[0076] The temperature of the secondary combustion zone is 1500 degrees Celsius.
[0077] In the step S3, the rapid cooling temperature is less than 100°C.
[0078] In the step S4, the proportions of the mixed parts are: 72.5 parts of clinker, 4.5 parts of gypsum, and 17.5 parts of fly ash. The specific surface area after grinding is greater than 380m 2 / kg.
[0079] Embodiment 4:
[0080] A staged combustion dry process cement production process comprises the following steps:
[0081] S1: Raw material pretreatment, crushing limestone, high silicon raw materials, construction waste, iron raw materials, and bituminous coal separately, and then mixing and homogenizing in a homogenizing pile;
[0082] S2: Gradual combustion and clinker burning, the mixed and homogenized raw materials are put into the rotary kiln for graded combustion to produce clinker;
[0083] S3: Clinker cooling: the clinker discharged from the kiln is rapidly cooled by a grate cooler;
[0084] S4: Cement grinding, mixing the clinker with gypsum and fly ash, and then grinding to obtain finished cement;
[0085] S5: The ground cement is stored in bulk silos or packed into bags by packaging machines.
[0086] In the step S1, the mass ratio of the raw materials is: 75 parts of limestone, 7.5 parts of high-silicon raw materials, 12.5 parts of construction waste, 7.5 parts of iron raw materials, and 4 parts of bituminous coal.
[0087] In the step S1, the particle size after crushing is less than 50 mm, and the water content of the mixture in the homogenization pile is less than 5%.
[0088] In the step S2, the rotary kiln has a primary combustion zone located in the decomposition zone at the kiln tail and a secondary combustion zone located in the main combustion zone at the kiln head;
[0089] The temperature of the primary combustion zone is 850 degrees Celsius, and low-oxygen multi-point air distribution is adopted, and the oxygen content of the air distribution is less than 5%;
[0090] The temperature of the secondary combustion zone is 1500 degrees Celsius.
[0091] In the step S2, the combustion process also includes a denitrification and denitrification method.
[0092] The implementation means of the denitrification and denitrification method include:
[0093] S21: Move the coal feeding point of the decomposition furnace to the top of the kiln tail smoke chamber or the cone of the decomposition furnace, and pyrolyze the coal powder in a low-oxygen environment to generate CO, CH4, and H2 reducing gases, which react with NOx in the kiln to achieve initial denitrification;
[0094] S22: Add a five-stage outlet pipeline denitrification spray gun, ammonia water and compressed air required for atomization, which are drawn out from the original denitrification system control cabinet, and the control system remains unchanged;
[0095] S23: Use a four-stage discharge pipe for discharge, and add a distribution valve, a flash valve, a discharge pipe and a spreading device to the four-stage discharge pipe to disperse part of the material in the four-stage discharge pipe downwards, so as to effectively control the bottom temperature of the decomposition furnace.
[0096] In the step S22, the concentration of the ammonia water is 10% and the flow rate is 0.8 L / t clinker.
[0097] In the step S3, the rapid cooling temperature is less than 100°C.
[0098] In the step S4, the proportions of the mixed parts are: 72.5 parts of clinker, 4.5 parts of gypsum, and 17.5 parts of fly ash. The specific surface area after grinding is greater than 380m 2 / kg.
[0099] The present invention has:
[0100] Synergy of staged combustion and denitrification: Reducing NO by staged oxygen-controlled combustion in the kiln x The amount of generation, combined with SNCR denitrification in the smoke chamber, the total denitrification efficiency is ≥85%;
[0101] Solid waste resource utilization: Construction waste can replace part of the limestone raw materials after crushing and homogenization, and the mixing ratio can reach 15%;
[0102] Waste heat utilization: The waste heat from the kiln tail gas is used for drying raw materials, reducing coal consumption by 10-15%.
[0103] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.
Claims
1. A staged combustion dry process for producing cement, characterized in that: The following steps are involved: S1: Raw material pretreatment, crushing limestone, high silicon raw materials, construction waste, iron raw materials, and bituminous coal separately, and then mixing and homogenizing in a homogenizing pile; S2: Gradual combustion and clinker burning, the mixed and homogenized raw materials are put into the rotary kiln for graded combustion to produce clinker; S3: Clinker cooling: the clinker discharged from the kiln is rapidly cooled by a grate cooler; S4: Cement grinding, mixing the clinker with gypsum and fly ash, and then grinding to obtain finished cement; S5: The ground cement is stored in bulk silos or packed into bags by packaging machines.
2. A staged combustion dry process cement production process according to claim 1, characterized in that: In the step S1, the mass ratio of the raw materials is: 70-80 parts of limestone, 5-10 parts of high-silicon raw materials, 10-15 parts of construction waste, 5-10 parts of iron raw materials, and 3-5 parts of bituminous coal.
3. A staged combustion dry process cement production process according to claim 1, characterized in that: In the step S1, the particle size after crushing is less than 50 mm, and the water content of the mixture in the homogenization pile is less than 5%.
4. A staged combustion dry process cement production process according to claim 1, characterized in that: In the step S2, the rotary kiln has a primary combustion zone located in the decomposition zone at the kiln tail and a secondary combustion zone located in the main combustion zone at the kiln head.
5. A staged combustion dry process cement production process according to claim 4, characterized in that: The temperature of the primary combustion zone is 800-900 degrees Celsius, and low-oxygen multi-point air distribution is adopted, and the oxygen content of the air distribution is less than 5%; The temperature of the secondary combustion zone is 1450-1550 degrees Celsius.
6. A staged combustion dry process cement production process according to claim 1, characterized in that: In the step S2, the combustion process also includes a denitrification and denitrification method.
7. A staged combustion dry process cement production process according to claim 6, characterized in that: The implementation means of the denitrification and denitrification method include: S21: Move the coal feeding point of the decomposition furnace to the top of the kiln tail smoke chamber or the cone of the decomposition furnace, and pyrolyze the coal powder in a low-oxygen environment to generate CO, CH4, and H2 reducing gases, which undergo redox reactions with NOx in the kiln to achieve initial denitrification; S22: Add a five-stage outlet pipeline denitrification spray gun, ammonia water and compressed air required for atomization, which are drawn out from the original denitrification system control cabinet, and the control system remains unchanged; S23: Use a four-stage discharge pipe for discharge, and add a distribution valve, a flash valve, a discharge pipe and a spreading device to the four-stage discharge pipe.
8. A staged combustion dry process cement production process according to claim 1, characterized in that: In the step S22, the concentration of the ammonia water is 8%-12%, and the flow rate is 0.7-0.9 L / t clinker.
9. A staged combustion dry process cement production process according to claim 1, characterized in that: In the step S3, the rapid cooling temperature is less than 100°C.
10. A staged combustion dry process cement production process according to claim 1, characterized in that: In the step S4, the proportions of the mixed parts are: 70-75 parts of clinker, 4-5 parts of gypsum, and 15-20 parts of fly ash. The specific surface area after grinding is greater than 380m 2 / kg.