对"神华煤直接液化厂"磨煤机选型的探讨

论述了神华煤直接液化犬工机选型的依据,认为ＲＰ９８３碗式中速磨煤机对高水分煤种具有良好的适应性,出力可满足液化制粉的要求。     

D-11D磨煤机出力的理论计算及试验研究

针对某电厂350 MW机组配备D-11D型双进双出钢球磨煤机的制粉系统存在出力不足等问题,本文通过对磨煤机出力的理论计算和制粉系统调整,分析了磨煤机出力不足的原因,提高了制粉系统出力。结果表明:磨煤机出力与通风量正相关,仅调整磨煤机运行方式增加磨煤机通风量并不能真正提高磨煤机的研磨能力。容量风门开度增大,磨煤机通风量增加使得研磨煤量增加的同时,煤粉变粗。如果磨煤机通风量不足,仅增加钢球装载量提高研磨能力也不能有效提高磨煤机出力。煤质变化后,为提高磨煤机出力,在增加钢球装载量,提高磨煤机研磨能力的同时,还需相应增加磨煤机的通风量,增强携带煤粉的能力。磨煤机运行方式未随煤质变化及时调整以及磨煤机钢球装载量不足导致研磨能力下降是造成磨煤机出力不足的主要原因。根据试验结果通过增加磨煤机钢球装载量及磨煤机通风量,保持热一次风母管风压7.0 k Pa不变,A、B、C三台磨煤机运行容量风门开度置于75%时,制粉系统总风量达到209 t/h,制粉系统总出力由128 t/h提高至137. 89 t/h,带负荷能力由280 MW提高至320 MW。容量风门开度置于90%时,制粉系统总出力提高至144.84 t/h,带负荷能力提升至337 MW,制粉系统总出力及带负荷能力显著提高。     

提高钢球磨煤机衬板使用寿命的对策

低速钢球磨煤机虽然有占地面积大、笨重、系统复杂、噪声大、耗电高、初投资高等缺点 ,但对煤种的适用性广 ,能在煤中混有铁块等杂物时长时间可靠地运行 ,维持一定的出力和煤粉细度 ,且单台出力高 ,检修周期长。所以大多数火力发电厂至今仍在使用。磨煤机运行时 ,钢球在磨制煤粉的同时 ,对筒体的衬板也存在冲击和磨损。因此普遍存在衬板磨损问题 ,其情况与煤质、衬板和钢球材质、硬度及安装运行工况等因素有关。如我公司热电厂的 5台钢球磨煤机中 ,1 #和 5 #磨换衬板后仅用 8个月就出现衬板断裂、磨漏和脱落等问题。其他磨煤机也有类同问题…     

中速磨煤机出力计算方法探讨

煤粉制备系统中常用中速磨煤机,而磨煤机选型时要进行出力计算。介绍了各种中速磨煤机的出力计算方法,重点对MPS型中速磨煤机的出力计算方法进行分析探讨,提出了一些看法和建议,供工程设计参考。     

球磨机失效钢球在线剔除装置及效能分析

球磨机是煤粉锅炉制粉系统的重要设备,适用范围广,可以磨制各种煤。磨煤机钢球在使用过程中会逐渐磨损,以致最后失效,如何将失效的钢球及时剔除,确保磨煤最佳出力一直以来是困扰我国电力生产的历史性问题。该文介绍一种球磨机失效钢球在线剔除装置及其应用情况。     

600 MW褐煤机组掺烧烟煤对MB型风扇磨性能的影响

为掌握褐煤掺烧烟煤后对MB型风扇磨煤机提升压头、研磨出力、干燥出力及运行参数选取的影响,在SO2风扇磨煤机上进行了褐煤掺烧烟煤的半工业性试磨试验以及MB3600/1000/4900三介质风扇磨的热平衡计算,同时在一维火焰燃烧试验炉和煤粉气流着火温度试验炉上进行了相应的燃烧性能测试。结果表明,劣质褐煤掺烧合适比例的优质烟煤,可提高机组的带负荷能力,且磨煤机的提升压头和干燥能力也能满足运行要求。需要注意的是,由于烟煤的磨损性能较褐煤强,可能导致打击板寿命的降低。     

蒸汽管回转干燥机在褐煤干燥上的应用

针对褐煤高水分、高挥发分、热稳定性差以及易自燃等特点,经过对比分析,选择适合褐煤干燥的技术方案,同时在传统蒸汽管回转干燥机的基础上,根据试验研究结果,摸索出适合褐煤干燥的蒸汽管回转干燥机结构和工艺参数,并成功地运用于高水分印尼褐煤的干燥。     

Shell炉磨煤和干燥系统磨煤机常见问题分析

对sheu煤气化工艺磨煤干燥系统流程及磨煤干燥系统主要设备磨煤机进行简介，对磨煤和干燥系统磨煤机常见的堵煤问题进行工艺和设备方面的分析，提出了相应的对策措施，解决问题使装置达到稳定运行。     

印尼高水分褐煤干燥特性研究

以印尼高水分褐煤为试验对象,采用蒸汽管回转干燥技术对其进行静态、动态干燥试验研究。褐煤干燥速率特性试验表明,褐煤粒径和质量基本相同时,干燥蒸汽温度越高,水分蒸发速率越快,褐煤干燥速率越大;褐煤质量相同时,褐煤粒径越小,干燥时间越短,干燥速率越大;褐煤粒径相同时,褐煤质量越小,干燥时间越短,干燥速率越大;褐煤干燥速率曲线常在煤中水分低于空干基水分前出现拐点,即进入干燥降速阶段。通过对褐煤干燥前后的粒径分布、热稳定性分析可知,褐煤干燥过程伴随着细颗粒煤粉的产生,褐煤干燥后细颗粒煤粉增加了14.87%;褐煤干燥前后TS6分别为10.3%和19.2%,均属于低热稳定性煤,且干燥后褐煤的热稳定性好于干燥前;干燥后褐煤的反应开始温度RI和燃尽指数Cb分别降低了7℃和0.1112,相差较小,均极易着火和燃尽。     

印尼煤全水分测定方法的研究

分别采用空气干燥法和通氮干燥法对不同印尼煤样品的全水分进行测定,并对测定结果进行分析。结果表明:两种方法测定全水分结果的重复性限均较好且精密度差异较小,但在准确度上存在差异。提出在开展第三方检验工作时,应选用更加准确的通氮干燥法。     

Fuel characteristics of molasses-impregnated low-rank coal produced in a top-spray fluidized-bed reactor

Upgrading low-rank coal (LRC) through various strategies is always an important issue. Here, we report the production of hybrid coals and an evaluation of their characteristics for use as a fuel in power plants. The hybrid coals (HCKs) were prepared by a combination of drying and biomass impregnation into an Indonesian LRC followed by a precarbonization process. We used a top-spray fluidized-bed reactor for drying, biomass impregnation, and precarbonization to produce hybrid coals that have improved fuel characteristics in terms of heating value, moisture readsorption, and combustion patterns. A systematic study reveals that experimental parameters, such as a bed temperature, bioliquid spraying procedure, and precarbonization temperature strongly influence the characteristics of the resulting hybrid coal, meaning that they have an important role in upgrading LRC. In particular, the hybrid coal prepared by a process of simultaneous drying and bioliquid spraying followed by precarbonization at 200–300°C showed high contents of fixed carbon, an improved heating value, lower moisture adsorption, and single combustion patterns in which the characteristics were dramatically upgraded for practical use as a fuel in power plants. In addition, the simultaneous process using a fluidized-bed reactor has great potential because it can achieve process simplification, reduce manufacturing costs, and handle coal particles easily.     

MP型中速磨煤机在水泥厂的应用

MP型中速磨煤机属于外加力型辊盘式磨煤机，是集碾磨、干燥、选粉三项功能为一身，具有对煤种适应性强，结构性能先进、节省能耗等特点的新型制粉设备。     

CFD modeling of MPS coal mill with moisture evaporation

Coal pulverizers play an important role in the functioning and performance of a PC-fired boiler. The main functions of a pulverizer are crushing, drying and separating the fine coal particles toward combustion in the furnace. It is a common experience that mill outlet pipes have unequal coal flow in each pipe and contain some coarse particles. Unequal coal flow translates into unequal air-to-fuel ratio in the burner, deviating from the design value and thus increasing unburned carbon in fly ash, NO_x and CO. Coarser particles at the mill outlet originate from poor separation and decrease the unit efficiency. In addition, coarser particles reduce burner stability at low load. Air flow distribution at the mill throat, as well as inside the mill, significantly influences the mill performance in terms of separation, drying, coal/air flow uniformity at the mill outlet, wear patterns and mill safety. In the present work, a three-dimensional computational fluid dynamics (CFD) model of the MPS Roll Wheel pulverizer at Alliant Energy's Edgewater Unit 5 has been developed. The Eulerian-Lagrangian simulation approach in conjunction with the coal drying model in Fluent, a commercial CFD software package, has been used to conduct the simulation. Coal drying not only changes the primary air temperature but it also increases the primary air flow rate due to mass transfer from coal. Results of the simulation showed that a non-uniform airflow distribution near the throat contributes significantly to non-uniform air-coal flow at the outlet. It was shown that uniform velocity at the throat improves the air and coal flow distribution at the outlet pipes. A newly developed coal mill model provides a valuable tool that can be used to improve the pulverizer design and optimize unit operation. For example, reject coal rate, which is controlled by the air flow near the mill throat, can be reduced. The model can also be used to further aid in identifying and reducing high temperature or coal-rich areas where mill fires are most likely to start.     

Shell煤气化磨煤干燥系统常见问题分析及解决

阐述Shell煤气化工艺磨煤干燥系统流程,磨煤干燥系统主要设备循环风机和磨煤机进行简介,Shell煤气化磨煤干燥系统试车及运行过程中实际遇到问题的原因浅析及采取相应措施解决问题达到稳定运行目的。     

呼伦贝尔褐煤等温干燥过程

以水分含量高达40 %的呼伦贝尔褐煤煤粉为实验物料,利用热重法研究了等温条件下的干燥特性,对比分析了温度、颗粒粒度对干燥过程的影响。实验结果表明,呼伦贝尔褐煤干燥过程具有明显的恒速干燥阶段,其特征与干燥温度和自由水含量密切相关。获得了呼伦贝尔褐煤煤粉在不同温度和粒度条件下的临界含水量(MC_cr)和平衡含水量(MC_eq),发现随着颗粒粒度的减小,褐煤煤粉干燥速率略有增大,但当粒度较小时,粒度因素对干燥过程的影响不明显。MC_cr与MC_eq均随温度的升高而减小,而随着颗粒粒度的减小,MC_cr略有降低,MC_eq略有增大。实验结果可以为褐煤制粉干燥工艺条件的选择和优化提供依据。     

水煤浆制浆工艺与专用设备的新发展

介绍了我国制浆工艺及专用设备的发展情况,新的生产工艺有低阶煤分级研磨高浓度制浆工艺、柯林斯达制浆新工艺、洪威高新能源制浆工艺、干法制浆工艺、辊压与球磨工艺;新的破磨设备包括高效节能破磨机、XP系列破碎机、反击(锤)式细碎机、超细预磨机、辊压粉碎机、新型立式超细磨机、高效制浆专用磨机和立式超细搅拌过滤磨机。     

Ferromagnetic and superparamagnetic contamination in pulverized coal

Although no significant major-element contamination is introduced by grinding coal in a steel pulverizer, abraded steel particles can conceivably affect the magnetic properties of pulverized coal. Magnetic and scanning-electron-microscope analyses of pulverized coal and coal fragments from the Herrin No. 6 seam in Illinois showed ferromagnetic and superparamagnetic contamination from the grinder. Significant changes in the magnetic properties of the coal were noted, indicating a total steel contamination of approximately 0.02 wt%. When coal samples were vibrated in the magnetic field of the vibrating-sample magnetometer, the superparamagnetic steel particles moved through the pulverized coal, and participated in the formation of multidomain clusters that in turn substantially affected the magnetization of the coal.     

低阶煤干燥脱水技术的研究

介绍了转筒式干燥工艺、流化床干燥工艺、气流床干燥工艺等蒸发干燥工艺和热力脱水工艺（HTD）、机械热挤压脱水工艺（MTE）、UBC低阶煤干燥提质技术等非蒸发脱水工艺的工艺流程、技术特点及发展现状等。分析了低阶煤脱水工艺系统建设过程中干燥工艺、厂址、干燥介质与能源消耗的选择原则和依据。发现低阶煤干燥脱水工艺的选择应考虑目标用户对产品质量的要求,产品加工工艺对提质煤水分的要求且应尽量选择安全可靠、能耗较小、成本较低的干燥技术。厂址的选择需多方面综合考虑。干燥介质的选择应因地制宜,同时必须综合考虑干燥介质的成本及安全性。较低的干燥能耗才能够保证干燥工艺的长期运行,并产生经济价值。低阶煤干燥脱水技术的研究为低阶煤干燥工艺的选择及良好运行提供参考。     

CMS煤磨选粉机的应用

在广州石井水泥公司的煤磨系统的改造中，CMS煤磨选粉机表现出选粉效率高，生产能力大，细度易控制，体积小，安全可靠等特点。