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
Cement production is a highly energy-intensive process, and the rotary kiln is the most important part of the process. Having a comprehensive model of the kiln in order to reduce manufacturing costs, better performanc...Cement production is a highly energy-intensive process, and the rotary kiln is the most important part of the process. Having a comprehensive model of the kiln in order to reduce manufacturing costs, better performance can be created. In this paper, the influence processes in a simulated cement rotary kiln and operating parameters on the output of the study were to develop and validate the systems using the same batch. The followings were examined: solid phase, gas and coating temperature change in a rotary kiln.展开更多
Rotary kiln is widely used for thermal disposal of solid waste due to its effectiveness and high efficiency in recent years.To further improve the processing efficiency,a newly designed rotary kiln with three-section ...Rotary kiln is widely used for thermal disposal of solid waste due to its effectiveness and high efficiency in recent years.To further improve the processing efficiency,a newly designed rotary kiln with three-section structure is proposed,and the behaviours of particle motion and heat transfer are investigated.Firstly,a lab-scale rotary kiln is manufactured,and experiments are carried out.Verified by experimental data,a CFD-DEM numerical model is developed to analyze the particle motion and heat transfer characteristics with the effects of inlet flue gas temperature,feeding rate and rotating speed.The results show that the outlet temperature increases linearly with the flue gas temperature,while it is negatively correlated with the feeding rate and rotating speed.In addition,the volumetric heat transfer coefficient in this complex rotary kiln is analyzed,the overall heat transfer coefficient is between 200 and 700 W/(m^(3)K).展开更多
The transport mechanisms of momentum, mass, species, and energy are investigated in detail for the ro-tary kiln process. The residence time prediction of the granular bed is well improved by considering different flow...The transport mechanisms of momentum, mass, species, and energy are investigated in detail for the ro-tary kiln process. The residence time prediction of the granular bed is well improved by considering different flow patterns in the drum. Introducing a mixed flow pattern of the basic slipping and slumping behaviour has the most important effect on the improvement of the residence time prediction. The granular bed is assumed to behave as a Bingham fluid in the active layer of the bed. The transport mechanisms of momentum, species, and energy are modelled on the basis of this assumption and using the kinetic gas theory. Additionally, a mathematical transformation is presented to save computa-tional time. The model results of the temperature field are in very good agreement with experimental data.展开更多
基金Project(11C26214202599) supported by the SME Technology Innovation Fund of Ministry of Science and Technology,China
文摘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.
文摘Cement production is a highly energy-intensive process, and the rotary kiln is the most important part of the process. Having a comprehensive model of the kiln in order to reduce manufacturing costs, better performance can be created. In this paper, the influence processes in a simulated cement rotary kiln and operating parameters on the output of the study were to develop and validate the systems using the same batch. The followings were examined: solid phase, gas and coating temperature change in a rotary kiln.
基金the National Natural Science Foundation of China(grant No.52306207)the Key R&D Program of Zhejiang province(grant No.2022c03056)+1 种基金the“Leading Goose”R&D Program of Zhejiang province(grant No.2023C03157)the National Key R&D Program of China(grant No.2018YFC1802102).
文摘Rotary kiln is widely used for thermal disposal of solid waste due to its effectiveness and high efficiency in recent years.To further improve the processing efficiency,a newly designed rotary kiln with three-section structure is proposed,and the behaviours of particle motion and heat transfer are investigated.Firstly,a lab-scale rotary kiln is manufactured,and experiments are carried out.Verified by experimental data,a CFD-DEM numerical model is developed to analyze the particle motion and heat transfer characteristics with the effects of inlet flue gas temperature,feeding rate and rotating speed.The results show that the outlet temperature increases linearly with the flue gas temperature,while it is negatively correlated with the feeding rate and rotating speed.In addition,the volumetric heat transfer coefficient in this complex rotary kiln is analyzed,the overall heat transfer coefficient is between 200 and 700 W/(m^(3)K).
文摘The transport mechanisms of momentum, mass, species, and energy are investigated in detail for the ro-tary kiln process. The residence time prediction of the granular bed is well improved by considering different flow patterns in the drum. Introducing a mixed flow pattern of the basic slipping and slumping behaviour has the most important effect on the improvement of the residence time prediction. The granular bed is assumed to behave as a Bingham fluid in the active layer of the bed. The transport mechanisms of momentum, species, and energy are modelled on the basis of this assumption and using the kinetic gas theory. Additionally, a mathematical transformation is presented to save computa-tional time. The model results of the temperature field are in very good agreement with experimental data.
