Dissertation > Industrial Technology > Electrotechnical > Power generation, power plants > Power plant > Thermal power plants, thermal power stations > Boilers and combustion systems

The Pulverizers Research of Key Equipment in the New Semi-Closed Coal Preparation Process

Author JiaDongLiang
Tutor WuXiaoGuang
School China University of Geosciences
Course Mechanical Engineering
Keywords Coal preparation process Coal mill Loading mechanism Finite Element Virtual Prototyping
CLC TM621.2
Type Master's thesis
Year 2013
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Coal preparation process is a kind of process making the coal a certain particle size of pulverized coal and fed to the boiler or vault.Large power plant boiler coal preparation process used by generating plant is earlier studied, which has been formed into reservoir process and straight blowing process. While the study of small power plant boiler coal preparation process is few. With the application and promotion of Coal Research Institute’s efficient pulverized coal industrial boilers, the needs of small and medium-sized coal preparation process is more and more urgent.Coal mill is a machine grinding the coal pieces into the coal dusts, it’s the core key equipment of the coal preparation process. The study of Coal mill is early, which has been formed high-speed, medium-speed and low-speed three categories products.While, the domestic coal mill study is majored in the comprehensive study or the overall performance characteristics of coal mill; but seldom in the design of new coal mill or the study of loading system and mechanical structure.Departure from the actual needs of the Coal Research Institute, this article designed a new storage coal preparation process with millions ton’s annual production. Furthermore, employing the modern design methods and finite element techniques designed a new medium-speed coal mill based on the new preparation process, and finally tested and verified the coal mill with the virtual prototyping process.Firstly, this article introduced the open and closed coal preparation process according to the basic concepts; then introduced the coal preparation process and equipment used by Coal Research Institute’s efficient pulverized coal industrial boilers, and it’s problems and shortcomings. Finally, designed a new storage coal preparation process flow with millions ton’s annual production through the comprehensive comparative analysis, which used the bag type dust collector and pulverized coal burner stove developed by the Coal Research Institute. Moreover, calculated out the volume of the coal storage1500m3, the volume of the bunker storage750m3.This article completed the process flow diagram and equipments’selection, provided useful assistance to the development and promotion to the Coal Research Institute’s efficiency pulverized coal boiler, simultaneously provided new idea for the research and development of small and medium-sized coal preparation process.Designing the coal mill, firstly, proposed the design requirements on the new technology, the use requirements and mechanical design. Secondly, design the overall program according to the design requirements,which the type of coal mill is speed roller ring, and transmission with three-stage reduction, the loading system is hydraulic type, and separator is combined. Through the comparative analysis, designed a new type of loading mechanism according to the knowledge of mechanical principles, and accomplished its kinematic and force calculations, obtained that the loading mechanism’s freedom of motion is2, the slider’s moving distance is131mm, and the external loading force is177KN. Simultaneously, designed the grinding roller shaft, firstly accomplished the preliminary design according to the general design methods of the shaft parts, and then check the strength of the grinding roller shaft applying the ANSYS Workbench software. Finally, accomplished the general assembly drawing through assembling the spares designed and selected. The design requirements of coal mill presented by this paper is of directly guiding significance for the further study of the coal mill’s performances. The design of the loading mechanism provided the theoretical basis for the follow-up virtual prototype testing and simulation analysis, and parameter references for the further trial of prototype. The design of the grinding rollers is the result of the effective integration of CAD and CAE technology, showing the modern design methods of the shaft parts integrally, which is of direct significance for the engineering practice.Finally, this article did kinematics and dynamics simulation of the coal mill by virtual prototyping technology. In kinematics simulation, this paper obtained that the degree of freedom of the loading mechanism was2, the slider displacement was131.674mm, In dynamics simulation, this paper obtained that the loading force of the coal mill is33951.6N in the177KN applied external force. Simulation results show that the exercise of the related parts of the coal mill to meet the design requirements, and the coal mill desired loading force is substantially identical with the calculated values, and the speed and acceleration curve of the loading hydraulic cylinder are also supported, which provides a theoretical basis for the subsequent design. In this paper, virtual prototyping technology is introduced into the design and development of the coal mills and coal chemical machinery, provide help for the further optimization of the coal mill and also a new idea for the design of coal chemical mechanicalThe thesis was divided into six chapters. The first chapter was the introduction, basing on the actual demand, outlined the research status of coal preparation processes and coal mill, proposed the purpose and significance of this article. The second chapter was the design of coal preparation process, through comparative analysis, for the lack of existing milling technology of CCRI, designed a set of the annual output of the pulverized coal boiler career development needs in a megaton of new silo type coal preparation, and had the selection and sizing of major equipment. The third chapter was design requirements for coal mill, proposed the design requirements of the new coal mill from the coal preparation process, the user and mechanical design. The fourth chapter was coal mill’s design, analyzed and compared to the existing loading mechanism, integrated respective advantages, designed a loading mechanism for easy access, completed the theoretical analysis and parameter calculation. In addition, we made use of modern design methods, through the design process:theoretical calculations-2D graphics-3D modeling-FEA, designed and checked the new coal mill grinding rollers. The fifth Chapter was virtual prototype simulation analysis, descript simulation technology, virtual prototyping technology and software ADAMS, selected the method of prototype model, had built the3D modeling of the new coal mill by Pro/E, established set of constraints and load in ADAMS, completed kinematics and dynamics simulation analysis, the results were analyzed and researched. The sixth chapter was full summary, overall rating for the design of coal preparation processes and coal mill instructions, pointing out that there are still problems.

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