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A Model for Predicting the Erosion Rate Induced by the Use of a Selective Catalytic Reduction Denitrification Technology in Cement Kilns Flue Gas 被引量:1
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作者 Yihua Gao Fuping Qian +5 位作者 Yi Sun Yue Wu Shenghua Wu Jinli Lu Yunlong Han Naijin Huang 《Fluid Dynamics & Materials Processing》 EI 2023年第8期1997-2011,共15页
Selective catalytic reduction(SCR)is a technology by which nitrogen oxides are converted with the aid of a catalyst into diatomic nitrogen and water.It is known that the catalyst can be easily eroded if a cement kiln ... Selective catalytic reduction(SCR)is a technology by which nitrogen oxides are converted with the aid of a catalyst into diatomic nitrogen and water.It is known that the catalyst can be easily eroded if a cement kiln with a high-dust content is considered.To understand this process,numerical simulations have been carried out considering a single catalyst channel in order to study the collision and erosion of fly ash and catalysts at meso scale.Based on a response surface methodology,the effects of five factors on the erosion rate have been studied,namely,the catalyst particle velocity,the particle size,the particle concentration,the incidence angle and the catalyst porosity.The results show that the influence of particle velocity,particle size and particle concentration is statistically significant and the particle size and incidence angle have a significant effect on the erosion rate.A quadratic polynomial prediction model for the erosion rate of honeycomb catalysts in cement kiln SCR reactors is finally proposed to support the future optimization of these systems. 展开更多
关键词 Cement kiln SCR denitrification catalyst erosion numerical simulation
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Multi-Objective Adaptive Optimization Model Predictive Control:Decreasing Carbon Emissions from a Zinc Oxide Rotary Kiln
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作者 Ke Wei Keke Huang +1 位作者 Chunhua Yang Weihua Gui 《Engineering》 SCIE EI CAS CSCD 2023年第8期96-105,共10页
The zinc oxide rotary kiln,as an essential piece of equipment in the zinc smelting industrial process,is presenting new challenges in process control.China’s strategy of achieving a carbon peak and carbon neutrality ... The zinc oxide rotary kiln,as an essential piece of equipment in the zinc smelting industrial process,is presenting new challenges in process control.China’s strategy of achieving a carbon peak and carbon neutrality is putting new demands on the industry,including green production and the use of fewer resources;thus,traditional stability control is no longer suitable for multi-objective control tasks.Although researchers have revealed the principle of the rotary kiln and set up computational fluid dynamics(CFD)simulation models to study its dynamics,these models cannot be directly applied to process control due to their high computational complexity.To address these issues,this paper proposes a multi-objective adaptive optimization model predictive control(MAO-MPC)method based on sparse identification.More specifically,with a large amount of data collected from a CFD model,a sparse regression problem is first formulated and solved to obtain a reduction model.Then,a two-layered control framework including real-time optimization(RTO)and model predictive control(MPC)is designed.In the RTO layer,an optimization problem with the goal of achieving optimal operation performance and the lowest possible resource consumption is set up.By solving the optimization problem in real time,a suitable setting value is sent to the MPC layer to ensure that the zinc oxide rotary kiln always functions in an optimal state.Our experiments show the strength and reliability of the proposed method,which reduces the usage of coal while maintaining high profits. 展开更多
关键词 Zinc oxide rotary kiln Model reduction Sparse identification Real-time optimization Model predictive control Process control
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Research on Remote Fault Detection System of Ceramic Kiln Based on 5G and IoT Technologies
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作者 LI Tao ZHAO Zengyi YU Zhongzhan 《International Journal of Plant Engineering and Management》 2023年第2期99-112,共14页
In order to overcome the defects of the existing technology that the detection of ceramic electric kiln faults takes a long time and costs a lot,an electric kiln control and fault detection device was designed.The wor... In order to overcome the defects of the existing technology that the detection of ceramic electric kiln faults takes a long time and costs a lot,an electric kiln control and fault detection device was designed.The working process of the device includes detection module,control module,start⁃stop module and switch module.The detection module detects the resistance circuit and sends a fault signal to the control module.The control module generates stop signal and fault information according to the fault signal,and starts the electric kiln when the fault signal is not received within the preset time.The start⁃stop module can monitor the internal temperature of the electric kiln and control the closing status of the switch module.The switch module is used to control the connection status of AC power and each resistance circuit in the kiln.Based on the 5G DTU or 5G module,the control module could send the information to mobile terminal under the ultra⁃reliable and low⁃latency communication(uRLLC)technical characteristics of 5G communication. 展开更多
关键词 ceramic electric kiln remote fault detection modbus protocol 5G communication
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Plant Test of Industrial Waste Disposal in a Cement Kiln 被引量:3
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作者 刘阳生 韩杰 白庆中 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2003年第1期102-105,共4页
Destruction of industrial waste in cement rotary kilns (CRKs) is an alternative technology for the treatment of certain types of industrial waste (IW). In this paper, three typical types of industrial wastes were co-i... Destruction of industrial waste in cement rotary kilns (CRKs) is an alternative technology for the treatment of certain types of industrial waste (IW). In this paper, three typical types of industrial wastes were co-incinerated in the CRK at Beijing Cement Plant to determine the effects of waste disposal (especially solid waste disposal) on the quality of clinker and the concentration of pollutants in air emission. Experimental results show that (1) waste disposal does not affect the quality of clinker and fly ash, and fly ash after the IW disposal can still be used in the cement production, (2) heavy metals from IW are immobilized and stabilized in the clinker and cement, and (3) concentration of pollutants in air emission is far below than the permitted values in the China National Standard-Air Pollutants Emission Standard (GB 16297-1996). 展开更多
关键词 INCINERATION industrial waste cement rotary kiln rotary kiln incinerator CLINKER
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A Short Communication on Refractories as Kiln Lining along Various Thermal Zones in Pre-calcining Cement Rotary Kiln
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作者 LI Bo DING Songxiong +1 位作者 XIAO Guoxian GAO Qianyu 《China's Refractories》 CAS 2017年第3期8-18,共11页
Modern cement rotary kiln is often large in size while rotating in high speed. Thermal condition within a rotary kiln is rather complex, exerting severe thermal and chemical attack on refractory of its kiln lining. In... Modern cement rotary kiln is often large in size while rotating in high speed. Thermal condition within a rotary kiln is rather complex, exerting severe thermal and chemical attack on refractory of its kiln lining. In the present paper, the cause that leads to refractory failure was analyzed; requirements for refractory to overcome such failure was discussed. Composites and properties of different refractories most often used as kiln lining were assessed, including magnesia - chrome bricks, magnesia spinel bricks, dolomite bricks, silicon carbide muUite bricks and castables etc. Recommendation was made for refractories with suitable composites and properties to be used as kiln lining in each specific zone to best counteract the severe thermal conditions. A cost-effective configura- tion was presented to assemble kiln lining for rotary kiln's different zones in line with the regulation at JC/ T 2196-2013 "Specifications of refractory for cement rotary kiln". Chromite-free refractories with property of high endurance to thermal attack and corrosion are required to be used in modern Pre-calcining cement rotary kilns. 展开更多
关键词 pre-calcining cement rotary kiln refractory for kiln lining characteristics
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A New Type of Cement Kiln——Annular Shaft Kiln
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作者 Li Buxin Zu Shufen 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 1989年第2期71-72,共2页
Annular shaft kiln invented by authors is an achievement in scientific research of Wuhan University of Technology. The invention-patent technology has been applyed recently to a φ2.2×7.7m circular shaft kiln of ... Annular shaft kiln invented by authors is an achievement in scientific research of Wuhan University of Technology. The invention-patent technology has been applyed recently to a φ2.2×7.7m circular shaft kiln of semi-mechnization in Tangshan National Cement Plant. The circular shaft kiln became an annular shaft kiln after a core tube was added in it as an inner annulation. This kiln has been proved to be successful in practice. It’s output after firing on 9th october 1989 has increased by 50%. The average clinker mark of over 525 has 展开更多
关键词 A New Type of Cement kiln Annular Shaft kiln
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An Innovative Process for Direct Reduction of Cold bound Pellets from Iron Concentrate with a Coal-based Rotary Kiln 被引量:10
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作者 ZHU De qing QIU Guan zhou +1 位作者 JIANG Tao XU Jin chang 《Journal of Central South University》 SCIE EI CAS 2000年第2期68-71,共4页
Successfully developed an innovative process of direct reduction of cold bound pellets from iron ore concentrate with a coal based rotary kiln, in comparison with the traditional direct reduction of fired oxide pellet... Successfully developed an innovative process of direct reduction of cold bound pellets from iron ore concentrate with a coal based rotary kiln, in comparison with the traditional direct reduction of fired oxide pellets in coal based rotary kilns , possesses such advantages as: shorter flowsheet, lower capital investment, greater economic profit, good quality of direct reduced iron. The key technologies , such as the composite binder and corresponding feasible techniques were employed in practice. A mill utilizing this process and with an annual capacity of 50 thousand ton DRI has been put into operation. 展开更多
关键词 DIRECT reduction ROTARY kiln cold BOUND PELLETS iron CONCENTRATE
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Flame image recognition of alumina rotary kiln by artificial neural network and support vector machine methods 被引量:18
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作者 张红亮 邹忠 +1 位作者 李劼 陈湘涛 《Journal of Central South University of Technology》 EI 2008年第1期39-43,共5页
Based on the Fourier transform, a new shape descriptor was proposed to represent the flame image. By employing the shape descriptor as the input, the flame image recognition was studied by the methods of the artificia... Based on the Fourier transform, a new shape descriptor was proposed to represent the flame image. By employing the shape descriptor as the input, the flame image recognition was studied by the methods of the artificial neural network(ANN) and the support vector machine(SVM) respectively. And the recognition experiments were carried out by using flame image data sampled from an alumina rotary kiln to evaluate their effectiveness. The results show that the two recognition methods can achieve good results, which verify the effectiveness of the shape descriptor. The highest recognition rate is 88.83% for SVM and 87.38% for ANN, which means that the performance of the SVM is better than that of the ANN. 展开更多
关键词 rotary kiln flame image image recognition shape descriptor artificial neural network support vector machine
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CFD prediction of physical field for multi-air channel pulverized coal burner in rotary kiln 被引量:8
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作者 马爱纯 周孑民 +1 位作者 欧俭平 李旺兴 《Journal of Central South University of Technology》 EI 2006年第1期75-79,共5页
A 3-D numerical simulation with CFX software on physical field of multi-air channel coal burner in rotary kiln was carried out. The effects of various operational and structural parameters on flame feature and tempera... A 3-D numerical simulation with CFX software on physical field of multi-air channel coal burner in rotary kiln was carried out. The effects of various operational and structural parameters on flame feature and temperature distribution were investigated. A thermal measurement was conducted on a rotary kiln (4.5m in diameter, 90m in length) with four-air channel coal burner to determine the boundary conditions and to verify the simulation results. The calculation result shows that the distribution of velocity near burner exit is saddle-like; recirculation zones near nozzle and wall are useful for mixture primary air with coal and high temperature fume. A little central airflow can avoid coal backing up and cool nozzle. Adjusting the ratio of internal airflow to outer airflow is an effective and major means to regulate flame and temperature distribution in sintering region. Large whirlcone angle can intensify disturbution range at flame root to accelerate ignition and mixture. Large coal size can reduce high temperature region and result in coal combusting insufficiently. Too much combustion air will lengthen flame and increase heat loss. 展开更多
关键词 CFD numerical simulation CFX physical field multi-air channel coal burner rotary kiln
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Leaching of iron concentrate separated from kiln slag in zinc hydrometallurgy with hydrochloric acid and its mechanism 被引量:7
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作者 Hong-jun WANG Zhi-yong LIU +4 位作者 Zhi-hong LIU Yu-hu LI Si-wei LI Wen-Hai ZHANG Qi-hou LI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2017年第4期901-907,共7页
It is taken as a novel prospective process to treat iron concentrate from hydrometallurgical zinc kiln slag forcomprehensive utilization of valuable metals by a hydrochloric acid leaching-spray pyrolysis method.The le... It is taken as a novel prospective process to treat iron concentrate from hydrometallurgical zinc kiln slag forcomprehensive utilization of valuable metals by a hydrochloric acid leaching-spray pyrolysis method.The leaching mechanism ofdifferent valuable metals was studied.The results revealed that the leaching rates of Ag,Pb,Cu,Fe,As and Zn were99.91%,99.25%,95.12%,90.15%,87.58%and58.15%,respectively with6mol/L HCl and L/S ratio of10:1at60°C for120min.The actionof SiO2in leaching solution was also studied.The results showed that the precipitation and settlement of SiO2(amorphous)adsorbedpart of metal ions in solution,which greatly inhibited the leaching of Cu,Fe,As and Zn,so it is crucial to control the precipitation ofamorphous SiO2. 展开更多
关键词 kiln slag iron concentrate hydrochloric acid leaching amorphous silica
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Mathematical models and expert system for grate-kiln process of iron ore oxide pellet production.Part Ⅱ:Rotary kiln process control 被引量:7
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作者 范晓慧 王祎 陈许玲 《Journal of Central South University》 SCIE EI CAS 2012年第6期1724-1727,共4页
Rotary kiln process for iron ore oxide pellet production is hard to detect and control.Construction of one-dimensional model of temperature field in rotary kiln was described.And the results lay a solid foundation for... Rotary kiln process for iron ore oxide pellet production is hard to detect and control.Construction of one-dimensional model of temperature field in rotary kiln was described.And the results lay a solid foundation for online control.Establishment of kiln process control expert system was presented,with maximum temperature of pellet and gas temperature at the feed end as control cores,and interval estimate as control strategy.Software was developed and put into application in a pellet plant.The results show that control guidance of this system is accurate and effective.After production application for nearly one year,the compressive strength and first grade rate of pellet are increased by 86 N and 2.54%,respectively,while FeO content is 0.05% lowered.This system can reveal detailed information of real time kiln process,and provide a powerful tool for online control of pellet production. 展开更多
关键词 mathematical model expert system one-dimensional temperature field rotary kiln iron ore oxide pellet
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Effects of Municipal Sewage Sludge on Fixation of Cr,Ni,Cu,and Zn during Co-processing of Heavy Metal-containing Waste in Cement Kilns 被引量:4
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作者 刘伟 CAO Haihua +4 位作者 徐竟成 LIU Jia HUANG Juwen HUANG Xiangfeng LI Guangming 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2018年第4期892-900,共9页
Cement raw meal with MSS and different heavy metals was blended to examine the fixation ratios, chemical species, and cement crystalline phases in clinkers. The results showed that blending MSS could decrease the fixa... Cement raw meal with MSS and different heavy metals was blended to examine the fixation ratios, chemical species, and cement crystalline phases in clinkers. The results showed that blending MSS could decrease the fixation ratio of Cr, Ni, Cu, and Zn in the produced clinker by 5% to 25%. And Cr, Cu, and Zn were mainly incorporated into clinkers as metal silicates, Ni was mainly solubilized in Mg O to form magnesium nickel oxides, and the transition phases were mainly metal aluminum oxides as indicated by X-ray diffraction. The reduction of fixation ratios was likely attributed to the presence of impure elements, such as sodium and phosphorus in MSS. In addition, high concentrations(eg, 1.7 wt%) of chlorine in MSS led to metal chloride formation that could vaporize Cu, Cr, Ni, and Zn. To summarize, introducing MSS would decrease the fixation ratios of heavy metals due to the presence of impure elements, such as sodium and phosphorus and chlorine. 展开更多
关键词 municipal sewage sludge heavy-metal fixation cement kiln CO-PROCESSING
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Grate-kiln pelletization of Indian hematite fines and its industrial practice 被引量:2
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作者 De-qing Zhu Feng Zhang +2 位作者 Zheng-qi Guo Jian Pan Wei Yu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2017年第5期473-485,共13页
Indian hematite fines normally have a high iron grade and minor impurities; they are usually used as sinter fines for feeding into a blast furnace. In this work, the grindability properties of two kinds of Indian hema... Indian hematite fines normally have a high iron grade and minor impurities; they are usually used as sinter fines for feeding into a blast furnace. In this work, the grindability properties of two kinds of Indian hematite fines and the roasting behaviors and induration characteristics of pellets made from these fines were revealed through experiments involving dry ball milling and small-scale and pilot-scale tests. In addition, the microstructures of the particles of ground India hematite fines and fired pellets were investigated using optical microscopy. On the basis of the results, a grate-kiln production line with an annual output of 1.2 Mt of oxidized pellets was established in India. This pellet plant operates stably and reliably, further confirming that preparing high-quality pellets with Indian hematite fines pretreated by dry ball milling is an industrially feasible process. © 2017, University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg. 展开更多
关键词 Ball milling Blast furnaces Industrial management kilns Milling (machining) PELLETIZING
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Improvement of geotechnical properties of sabkha soil utilizing cement kiln dust 被引量:3
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作者 Abdullah A.Al-Homidy Mohammed H.Dahim Ahmed K.Abd El Aal 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2017年第4期749-760,共12页
Improvement of properties of weak soils in terms of strength,durability and cost is the key from engineering point of view.The weak soils could be stabilized using mechanical and/or chemical methods.Agents added durin... Improvement of properties of weak soils in terms of strength,durability and cost is the key from engineering point of view.The weak soils could be stabilized using mechanical and/or chemical methods.Agents added during chemical stabilization could improve the engineering properties of treated soils.Stabilizers utilized have to satisfy noticeable performance,durability,low price,and can be easily implemented.Since cement kiln dust(CKD) is industrial by-product,it would be a noble task if this waste material could be utilized for stabilization of sabkha soil.This study investigates the feasibility of utilizing CKD for improving the properties of sabkha soil.Soil samples are prepared with 2% cement and 10%,20% or 30% CKD and are tested to determine their unconfined compressive strength(UCS),soaked California bearing ratio(CBR) and durability.Mechanism of stabilization is studied utilizing advanced techniques,such as the scanning electron microscope(SEM),energy dispersive X-ray analysis(EDX),backscattered electron image(BEI) and X-ray diffraction analysis(XRD).It is noted that the sabkha soil mixed with 2% cement and 30% CKD could be used as a sub-base material in rigid pavements.The incorporation of CKD leads to technical and economic benefits. 展开更多
关键词 Sabkha soil Geotechnical properties Soil improvement Cement kiln dust(CKD) Unconfined compressive strength(UCS) Soaked California bearing ratio(CBR) Durability
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Influence of MnO_2 Mineralizer on the Crystal Structure,Properties of SiC Kiln Furniture Bonded with Fine Silicon Powder 被引量:4
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作者 RUAN Yu-Zhong WU Wan-Guo +2 位作者 YU Yan ZHAN Hong-Bing LIN Chun-Ying(Department of Chemlcal Engineering, Fuzhou University, 350002) 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 1997年第5期397-402,共6页
The properties of SiC kiln furniture bonded with fine silicon powderare related to the bonder’s crystal structure. At high temperature, it will crystallize ina-cristobalite with great bulk effect. MnO2 mineralizer ca... The properties of SiC kiln furniture bonded with fine silicon powderare related to the bonder’s crystal structure. At high temperature, it will crystallize ina-cristobalite with great bulk effect. MnO2 mineralizer can make a-cristobalite convertto a-tridymite whose bulk effect is small. The crystal structure and its amount were investigated with XRD technique. The influence of different amounts of MnO2 on thecrystal structure and polycrystal transformation, and that of crystal structure on theproperties of kiln furniture were studied. The best proportion of MnO2 added was determined to be 2.0%. 展开更多
关键词 MnO_2 mineralizer fine silicon powder SiC kiln furniture
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Numerical analysis of behavior of active layer in rotary kilns by discrete element method 被引量:3
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作者 谢知音 冯俊小 《Journal of Central South University》 SCIE EI CAS 2013年第3期634-639,共6页
The behavior of the active layer of material bed within rotary kilns plays a key role in industrial applications.To obtain its influences on industrial process,different regimes of particle motion have been simulated ... The behavior of the active layer of material bed within rotary kilns plays a key role in industrial applications.To obtain its influences on industrial process,different regimes of particle motion have been simulated by discrete element method(DEM) in three dimensions under variant rotation speeds,filling degree,based on the background of induration process of iron ore pellets.The influences of the mentioned factors on the maximum thickness of the active layer and the average velocity of particles have been investigated.The average velocity of particles increases with Froude number following the power function over a wide range,and the maximum thickness rises with increasing rotation speed in a way of logarithm.The influence of the filling degree f on the maximum thickness exhibits a good linearity under two classic regimes,but the increasing of the average velocity of the active layer is limited at f=0.4.This basic research highlights the impact of the active layer within rotary kilns,and lays a good foundation for the further investigation in mixing and heat transfer within the particle bed inside rotary kilns. 展开更多
关键词 rotary kiln particle motion discrete element method active layer
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Enhanced recovery of zinc and lead by slag composition optimization in rotary kiln 被引量:3
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作者 Hong-fu LIN Wei WENG +1 位作者 Shui-ping ZHONG Guan-zhou QIU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第9期3110-3122,共13页
High-efficiency recovery of Zn and Pb from silicon-rich zinc leaching residues is realized in a rotary kiln.Characterizations by means of XRD,SEM,EDS and ICP reveal that the leaching residue contains 12.4 wt.%SiO_(2),... High-efficiency recovery of Zn and Pb from silicon-rich zinc leaching residues is realized in a rotary kiln.Characterizations by means of XRD,SEM,EDS and ICP reveal that the leaching residue contains 12.4 wt.%SiO_(2),16.1 wt.%Zn,and 7.4 wt.%Pb.Thermodynamic analysis shows that metallic vapor of Zn and Pb can be easily generated from the zinc leaching residue at 1150-1250°C inside the rotary kiln.Viscosities and melting points of 13 slag compositions were analyzed and three slag compositions(47wt.%SiO_(2)-23wt.%CaO-30wt.%FeO,40wt.%SiO_(2)-28wt.%CaO-32wt.%FeO,and 40wt.%SiO_(2)-30wt.%CaO-30wt.%FeO)possessed the desirable physical properties,with the melting point and viscosity in the range of 1150-1280°C and 0.2-0.5 Pa·s,respectively.The industrial tests show that adopting the optimized slag composition can contribute to very high recovery rates of Zn and Pb(97.3%for Zn and 94.5%for Pb),corresponding to slags with very low average contents of Zn and Pb(0.51 wt.%Zn and 0.45 wt.%Pb).The National-Standard leaching tests of the water-quenched slags result in 1.82 mg/L Zn,~0.01 mg/L Cu,0.0004 mg/L As,~0.01 mg/L Cd,0.08 mg/L Pb,and~0.02 mg/L Hg in the leachate,verifying the detoxification of the zinc leaching residue at the same time. 展开更多
关键词 zinc leaching residues metals recovery rotary kiln slag composition optimization DETOXIFICATION
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Increasing Plant Availability by Mechanical Checking of the Cement Rotary Kiln Axis 被引量:2
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作者 张云 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2001年第3期76-78,共3页
A periodic check of the cement rotary kiln axis is needed withinthe framework of preventive ma- intenance for maintaining high plantavailability. The fourth generation 'KAS-4' measuring system wasdevel- oped b... A periodic check of the cement rotary kiln axis is needed withinthe framework of preventive ma- intenance for maintaining high plantavailability. The fourth generation 'KAS-4' measuring system wasdevel- oped by Wuhan University of Technology in 1999. The system canbe carried out with rotating or stationary kiln plant. The same istrue of the measurement of tire and supporting roller diameters, theclearance of tires, the po- sition of rollers, the machining of tiresand rollers, the slops of roller surfaces, the deflection of gear,the axis of kiln. The system has been applied to the measurement for10 set of cement rotary kiln in China. 展开更多
关键词 cement kiln AXIS DIAMETER
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Present Synthesizing Situation and Application Mechanism of Hercynite in Cement Kilns 被引量:2
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作者 MA Shulong LI Yong +2 位作者 LI Yue LI Hui SUN Jialin 《China's Refractories》 CAS 2011年第3期6-10,共5页
The magnesia -hercynite bricks offer a new lining to rotary cement kiln. They are well adopted and widely used in the high temperature zone of cement kiln, and have obtained good performance at rigorous and severe wor... The magnesia -hercynite bricks offer a new lining to rotary cement kiln. They are well adopted and widely used in the high temperature zone of cement kiln, and have obtained good performance at rigorous and severe working conditions. The synthesis of hercynite requires a suitable atmosphere with proper O2 partial pressures which makes sure FeO can stably exist at the synthesizing temperature. Current industrial production of hercynite mainly adopts fused method. The other method, sinte- ring method, is not mature and needs further research. The magnesia - hercynite brick shows high hot toughhess, high adhesion strength to kiln crust, and good corrosion resistance to alkali salt in cement kilns. The mismatching of thermal expansion between magnesia and hercynite can improve the thermal shock resistance of the bricks, but the oxidation of partial Fe^2+ , the high temperature solution, and low temperature exsolution of transgranular secondary spinel lead to cubical expansion, .formation of more cracks, and poor thermal shock resistance of the bricks. 展开更多
关键词 Magnesia - hercynite bricks Synthesizing method Application mechanism Cement kiln
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Mathematic simulation of heat transfer and operating optimization in alumina rotary kiln 被引量:1
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作者 易正明 肖慧 +2 位作者 宋佳霖 马光柏 周孑民 《Journal of Central South University》 SCIE EI CAS 2013年第10期2775-2780,共6页
Based on the analysis of material motion in the axial direction, heat transfer and mass transport processes in a rotary kiln, and combining with pulverized coal combustion, material pyrogenation, cooling of furnace wa... Based on the analysis of material motion in the axial direction, heat transfer and mass transport processes in a rotary kiln, and combining with pulverized coal combustion, material pyrogenation, cooling of furnace wall finally, and heat transfer and mass transport equations, the combined heat transfer mathematical model for alumina rotary kiln was built up. According to the in-site real operation parameters, the heat transfer mathematical model was solved numerically for an alumina rotary kiln to predict the temperature profiles of gas and material in the axial direction. The results show that as the excess air coefficient reduces from 1.38 to 1.20, the temperature of the sintering zone increases and the length decreases. However, as the excess air coefficient reduces from 1.20 to 1.10, the temperature of the sintering zone decreases and the length increases. When the mixed coal amount at the end of kiln is reduced from 68.6 kg/t to 62.0 kg/t and the burned coal amount at the head of kiln correspondingly increases from 155.3 kg/t to 161.9 kg/t, the sintering zone temperature increases and the length reduces. The suitable excess air coefficient and mixed coal amount at the end of kiln are recommended for the rotary kiln operation optimization. 展开更多
关键词 ALUMINA ROTARY kiln heat TRANSFER MATHEMATICAL mode temperature PROFILE
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