火电厂锅炉辅机磨煤机检修故障及处理技术研究

随着社会经济的不断发展,人们的电力需求日益增长,在促进电力事业蓬勃发展的同时,对各项设备稳定可靠运行提出了更高的要求。在火电厂锅炉辅机磨煤机运行方面,一旦发生故障问题,就会对火电厂正常生产构成极大的威胁,加强磨煤机检修故障及处理技术研究与分析十分必要。根据火电厂锅炉辅机磨煤机的工作原理,对火电厂锅炉辅机磨煤机常见故障问题进行细致分析,并从引进先进设备、定期检查维护和加强故障处理等方面入手,提出几点有效处理策略,以供相关人员参考。     

电厂锅炉磨煤机的选型分析与应用

磨煤机是燃用煤粉锅炉的重要辅助设备，本文比较了电厂常用低、中、高速磨煤机的优缺点，并探讨了不同制粉系统的选型问题，可见不同的制粉系统适用于不同的煤种及所选择的磨煤机，需要根据实际情况进行选择。     

HP碗式中速磨煤机在碾磨褐煤中的应用

介绍了褐煤特性,燃用褐煤火电机组对磨煤机的要求,HP碗式中速磨煤机工作原理及其结构特点的分析,并结合磨煤机实际运行情况,论述了HP碗式中速磨煤机碾磨褐煤的可行性.给准备选用褐煤作为主要燃料的火电厂选择磨煤机时提供借鉴.     

双进双出磨煤机爆炸要因分析及风险防范措施

从爆炸五大因素及《电站磨煤机及制粉系统选型导则》出发,对南京化学工业园热电有限公司锅炉双进双出钢球磨煤机爆炸进行要因分析,找出了重点项,针对要因制定与实施对策,并进行了效果确认,以彻底管控、杜绝双进双出钢球磨煤机爆炸事故的发生。     

试析褐煤锅炉磨煤机选型和煤粉水分选取

围绕褐煤锅炉磨煤机的选型以及煤粉水分的选取方法展开研究,在探讨磨煤机设备选型的基础上,分别阐述了多种煤粉水分选取的方法,并重点介绍按DL/T5145-2002标准为依据的两种选取方法。经试验证明,以煤粉水分Mpe、设备出口介质温度t2和全水分Mt三方的关系为依据进行计算,才能有效确保磨制粉系统的合理设计,最终采用MPS225-HI-II和HP1103两种中速磨煤机。     

MPS-HP-II型中速磨煤机磨制褐煤与LCC煤粉的混煤的可行性研究

通过对准哈和乌拉盖褐煤及其提质后的LCC煤粉各自特点的分析,确定磨煤机的出力计算原则和方法。通过分析磨煤机的碾磨出力计算及热平衡计算,从而解决磨煤机振动问题。根据相关计算原则进行选和设计,发现MPS-HP-II型中速磨煤机完全能满足磨制褐煤与LCC煤粉的混煤要求。     

钢球磨煤机出口温度软测量方法

针对火电厂制粉系统的钢球磨煤机出口温度难于测量的问题,提出了运用软测量方法测量其温度值的方法,并利用所建模型对系统进行了仿真,仿真结果较好。     

中速磨煤机液压加载系统原理及故障分析

以意大利ATOS/Scoda公司的中速磨煤机液压加载系统为例,介绍了中速磨煤机液压加载系统的主要组成和工作原理,以及液压加载系统各压力的调整方法,总结该类型液压加载系统故障的原因及故障分析原则,并利用分析原则对液压加载系统的常见故障进行分析,得出液压加载系统故障主要有油泵泄漏、电磁阀卡涩、液压缸密封损坏、比例溢流阀故障等原因。     

中速磨煤机的常见故障分析及点检管理

介绍了中速辊盘式磨煤机在运行中常见的故障,并进行了原因分析;根据发生故障的原因,确定了磨煤机的点检部位及主要点检内容,并对点检内容进行了有效管理,能够及时准确断定磨煤机的健康状态等级,针对不同等级采取相应措施,避免"过维修"和"欠维修"的发生.     

火电厂料位计选型及无源核子料位计的应用

针对火电厂生产流程中各类固体料位测量难点进行分析，提出几种料位计选型的解决方案并进行比较。给出了无源核子料位计在固体测量中的优势及其在火电厂中的应用。     

故障树分析及其在制粉系统故障诊断中的应用

利用故障树分析法对火力发电厂制粉系统的常见故障进行了分析研究，建立了制粉系统的故障树，涵盖了球磨机、给煤机、排粉机、粗细粉分离器的常见故障，求出了其最小割集，给出了制粉系统发生故障的原因及导致故障各种原因组合的可能性。并且以球磨机为例给出了故障树分析的具体应用，通过球磨机振动信号的采集与分析，对球磨机的机械部件故障进行诊断。故障树分析法给制粉系统的故障智能诊断提供了一种有效的方法，为故障维修及故障预防提供了指导。     

磨煤机料位测量方法回顾与展望

针对球磨机运行特性。有效监测及控制钢球磨煤机的料位,是制粉系统实现优化运行、节能降耗的关键。本文对目前磨煤机料位测量中采用的几种主要测量方式做了介绍,并对磨煤机料位的测量进行了展望。     

Focused ion beam/scanning electron microscopy studies of Porcellio scaber (Isopoda, Crustacea) digestive gland epithelium cells

The focused ion beam (FIB) was used to prepare cross sections of precisely selected regions of the digestive gland epithelium of a terrestrial isopod P. scaber (Isopoda, Crustacea) for scanning electron microscopy (SEM). The FIB/SEM system allows ad libitum selection of a region for gross morphologic to ultrastructural investigation, as the repetition of FIB/SEM operations is unrestricted. The milling parameters used in our work proved to be satisfactory to produce serial two-dimensional (2-D) cuts and/or three-dimensional (3-D) shapes on a submicrometer scale. A final, cleaning mill at lower ion currents was employed to minimize the milling artifacts. After cleaning, the milled surface was free of filament- and ridge-like milling artifacts. No other effects of the cleaning mill were observed.     

高速铣削曲面工件的表面粗糙度仿真

在实际生产中,空间曲面一般采用行切法加工。无论是三坐标还是两坐标联动铣削,走刀行距的选择对加工表面粗糙度都有很大影响。本文针对球头铣刀对Bezier双三次曲面工件的高速铣削,结合走刀行距经验公式,提出了一种表面粗糙度的仿真算法,并通过仿真实例进行了验证。     

Programmable end milling of thermoplastics

The end milling of industrial and engineering thermoplastics on numerically controlled machine tools is considered. Specifically, attention focuses on the sources and prevention of machining defects. Recommendations are made regarding the selection of the tool geometry, the cutting conditions, and the mill trajectory.     

高能球磨处理对碳质中间相结构及高温摩擦特性的影响

采用高能球磨法对煤焦油沥青碳质中间相进行了非平衡处理,利用X射线衍射和激光Raman光谱技术研究了中间相高能球磨前后的结构变化,并且使用SRV高温摩擦磨损试验机考察了碳质中间相的摩擦性能。结果表明:高能球磨处理导致中间相的结晶有序度下降,微晶石墨平面尺寸减小,表明高能球磨处理促使其向无定形结构转变。碳质中间相具有高温润滑效应,高能球磨处理能够在一定程度上促进碳质中间相发生摩擦机械诱发的石墨化转变,从而对碳质中间相的高温润滑效应有一定促进作用。     

不等距立铣刀切削力模型的建立及试验分析

在特定铣削条件下,建立了多齿不等距铣刀的切削力模型,并通过正交试验验证所建的切削力模型;通过分析不同的切削参数对切削力系数的影响,综合确定了在小切削宽度铣削过程中合理选用切削参数的基本原则。     

Design and fabrication of a new micro ball-end mill with conical flank face

Micro ball-end milling is an efficient method for the fabrication of micro lens array molds. However, it is difficult to meet the machining quality of micro dimple molds due to the wear and breakage of the milling cutter, which presents large challenges for designing geometric structure and edge strength of micro ball-end mills. In this study, a new configuration of a micro ball-end mill for micro dimple milling is designed and named the micro conical surface ball-end mill. The cutting edge is formed by intersecting the conical surface and the inclined plane. A practical grinding method is proposed based on the kinematic principle of the six-axis computer numerical control (CNC) grinding machine for micro conical surface ball-end mills and is validated by grinding simulations and experiments. Micro dimple milling experiments are conducted on the hardened die steel H13 to investigate the cutting performance of the mill. The milling force, the micro dimple roundness error, and the tool wear morphology are observed and analyzed. The results show that the radial milling force is more stable and the wear resistance is improved for the micro conical surface ball-end mill compared to the traditional micro spiral blade ball-end mill. Therefore, a more stable roundness at the entrance hole of the micro dimple can be obtained by using this design after a number of micro dimples have been milled.     

高效铣削镍基高温合金GH4169的有限元数值模拟

在DEFORM软件中,根据实际加工情况建立整体硬质合金立铣刀加工镍基高温合金GH4169的三维有限元仿真分析模型。针对镍基高温合金GH4169加工效率低和切削刃磨损严重的问题,采用单因素试验法仿真探讨了切削用量(v、f_z、a_p、a_e)对切削力和切削温度的影响规律。获得了能有效提高镍基高温合金GH4169加工效率的切削用量,为实际加工中实现高效铣削镍基高温合金切削用量的选择提供依据。     

A study on the micro tooling for micro/nano milling

Many researches have studied the micro tools either by simulations or experiments showing that the micro tools play very important roles in micro/nano machining, and micro tool geometries have a direct impact on the final machining quality. Commercially available micro milling tools are usually simply made from downsizing of macro milling tools, which may not be able to be accurately fabricated. Custom micro milling tools have been created by some researchers, but no design criteria for micro milling tools have been introduced. The above factors constrain the development of effective micro milling tools and consequently constrain the researches on micro/nano milling. Based on former researcher??s work, this paper tries to introduce the design criteria for the custom micro tooling. Firstly, the extent typical micro milling tools are studied, and their drawback/limitations are summarized. Secondly, experimental evaluations of the key drawback/limitations are processed. Thirdly, the design criteria for custom micro milling tools are proposed, and corresponding design process is introduced. Then, a new micro hexagonal end mill has been designed based on these criteria. Finally, a polycrystalline diamond micro hexagonal end mill with a diameter of 0.5?mm was fabricated by wire electrical discharge machining, and the evaluation experiments for the hexagonal end mill have been processed on a nano milling center. Experimental results show the newly designed hexagonal end mill can achieve submicron level surface roughness and has simultaneously high-accuracy side and bottom machining capabilities.