【作者】 郝娟；

【导师】 张洪；

【作者基本信息】 中国矿业大学 ， 化学工艺， 2012， 博士

【摘要】 煤炭作为我国的主要能源资源，其清洁高效利用对减少燃煤环境污染、节约煤炭资源具有重要意义。本论文从煤的燃烧过程、煤中矿物质分布、煤粉燃烧特性等方面，对粒径尺寸和矿物质分布、煤粉燃烧特性之间规律等方面国内外研究现状进行了综述。针对目前煤炭主要利用途径——煤粉燃烧，研究了工业粉煤过程中矿物在煤粉中分布影响规律、煤粉中矿物随粒径的分布规律及其对燃烧特性的影响，以期为煤粉分级燃烧方法在新型干法水泥厂的工业应用提供基础数据，为有效利用劣质煤资源、实现煤粉高效燃烧利用提供理论指导。本文首先研究了工业单煤煤粉中矿物质分布。试验采集的河南新乡同力水泥厂（HN）、山西西城水泥厂（SX）和江苏南京中国水泥厂（JS）三个水泥厂煤粉样品是不同变质程度的烟煤，三个出磨煤粉都呈现出灰分随密度级别的增加呈递增，随着粒度增加而降低的规律。煤样的产率分布整体分布状态呈哑铃型，矿物质和有机质分离程度较高。基于煤粉浮沉试验和激光粒度分析试验结果，通过数学计算过程的推导，得到了煤粉中各粒级产率、灰分和挥发分的计算公式。该数学模型的建立为研究煤粉组成的分布提供了理论支持。对于工业现场混煤煤粉的研究表明：所采集广西华宏水泥有限公司（HH）、广西华润水泥有限公司（HR）、江西万年青水泥有限公司（WNQ）、山西威顿水泥有限公司（WD）和安徽海螺（狄港）水泥有限公司（DG）的混煤煤粉与单煤工业煤粉类似，都呈现出灰分随着粒度增加而降低的规律。确定合适的分级粒度，经分级可以得到高质量的低灰煤粉。煤粉中整体呈现出高密度级煤样产率随着粒度增大而逐渐降低的趋势，说明随着粒度增大外在矿物含量越来越少，灰分随粒度的变化是由高密度级煤样主导的。本文还研究了磨煤过程和混煤对煤粉中矿物质分布规律的影响。试验采集的安徽皖北矿务局烟煤(WB)、江西萍乡无烟煤(PX)和山西大同烟煤(DT)煤样灰分都呈现出随粒度增大而增加的趋势，贵州六盘水无烟煤(LP)煤样各个粒度级别的灰分变化不大，且与原煤样的灰分相近。同一煤样粉磨到不同细度，其灰分—粒度曲线变化趋势一致。同一煤样用不同粉磨方式制备的煤粉，其粒度与灰分的变化因煤样而异，粉磨方式对煤粉中矿物质随粒度的分布具有较大影响。利用振动磨研究了混煤对矿物质分布的影响，以5:5混配的WB与DT、WB与LP、WB与云南小龙潭褐煤（LT）混煤制备15%筛余细度煤粉，对混煤各密度级的工业分析结果表明不同煤种混配导致产率随密度的变化不同。各混煤的灰分都随着密度增加而逐渐增加，而挥发分都随着密度增加而逐渐降低。WB与DT、WB与LP混煤各密度级煤粉的平均粒度都随着密度增加先减小后增大。混煤对燃烧特性影响规律的研究表明：在相同实验条件、掺混比例情况下，烟煤和无烟煤掺混，先磨后混煤粉除了着火性能不如先混后磨外，其他燃烧特性指标都好于先混后磨，先磨后混掺混方式的综合燃烧性能好于先混后磨掺混方式；烟煤和烟煤掺混，两种掺混方式混煤各项着火特性、燃烧特性相近；烟煤和褐煤掺混，先磨后混混煤燃烧性能稍好于先混后磨混煤。烟煤和无烟煤混煤的燃烧受掺混方式的影响最明显。无论哪种掺混方式混煤，燃烧反应性能烟煤和褐煤掺混最好，烟煤和无烟煤掺混最差，烟煤和烟煤掺混居中。先磨后混掺混方式混煤燃烧性能受煤种影响较明显。用热重分析法研究了烟煤和无烟煤各筛分粒径煤粉的燃烧特性。对不同筛分粒径煤粉样品的热重曲线、着火温度、燃烬温度、最大失重速率及其对应温度Tmax、转化率和转化速率随温度变化曲线进行了分析对比。在相同实验条件下，烟煤煤粉随着筛分粒径的减小，燃烧的热重曲线向低温区移动。煤粉的着火、燃烬性能、燃烧稳定性、燃烧反应活性等整体燃烧性能都得到改善，并且粒径越小这种改善越明显。无烟煤筛分粒径中只有小粒径煤粉的燃烧热重曲线向低温区移动明显。筛分粒径越小，煤粉的着火、燃烧稳定性、燃烧反应活性越好，燃烬温度越低，但燃烬度不是粒径越小越好。粒径对煤粉整体燃烧性能的影响，烟煤大于无烟煤。该论文有图127幅，表56个，参考文献195篇。更多还原

【Abstract】 Coal is the main energy resource in China. Clean and effective utilization of coal issignificant to reduce coal-combusting-pollution and to save coal energy. In terms of theprocess of coal combustion, the distribution of minerals in the coal and the burningcharacteristics of coal, etc. the progress in the mutual relations of the particle size, thedistribution of minerals, the burning characteristics of pulverized coal at home and abroad arereviewed. Because the main utilization method of coal is combustion, the distribution andinfluence of minerals in the pulverized coal from the industrial pulverizing process are studied.The distribution of minerals in the pulverized coal chaning with the size and its influence onthe characteristic of combustion are analyzed, which are in order to provide basic data for theindustrial application of particle size grading combustion of pulverized coal in the new dryprocess cement plant. All of above have provided theoretic guidance for the effectiveutilization to the poor quality coal, strengthening the combustion of pulverized coal. It is alsosignificant for the efficient and clean utilization of coal in the Coal-fired power plant.The research on the industrial single pulverized coal shows that the samples ofpulverized coal from the Tong Li Cement Plant in Xixiang Henan (HN), Xicheng CementPlant in Shanxi (SX) and China Cement Plant in Nanjing Jiangsu (JS) are different rankbituminous. The ash of three pulverized coal sample are increasing with the increase ofdensity fraction and decreasing with the increase of the particle size. The yield distribution ofcoal sample is like a dumbbell which means the separation degree of minerals and organics ishigh. Minerals in the SX coal sample existed in the form of the external mineralindependently.Based on the results of the float and sink test and the laser particle size analysis, thecalculation formula of ash, volatile and the yeild of each size friction in the pulverized coalwere obtained by the deduction of the mathematic calculation process. The establishment ofthe mathematical model provides the theoretical support to the research on the distribution ofthe composition of the pulverized coal.Research on the mixed pulverized coal from the industrial field showed that the mixedpulverized coal samples collected from Guangxi Hua Hong Cement Co., Ltd.（HH）、GuangxiCR Cement Co., Ltd.(HR)、Jiangxi Evergreen Cement Co., Ltd.(WNQ)、Shanxi WittonCement Co., Ltd.（WD）and Anhui Conch (Di Kong) Cement Co., Ltd.(DG) indicated a lawthat the ash decreases with the increase of the particle size. By determining the appropriate classification size of particles, high-quality and low ash pulverized coal can be obtained afterthe classification after using the classification method. Samples of the pulverized coal showthe trend that the yield of high density coal sample decreases with the increasing particlesize,which shows that the content of external mineral decrease with the increasing particlesize and the change of the ash with the particle size is lead by the high density fraction.The influence of the grinding process and coal blending on mineral distribution wasresearched, it indicates that bituminous coal from Wanbei Ming Bureau(WB), anthracitic coalfrom Jiangxi Pingxiang(PX) and bituminous coal from Shanxi Datong（DT） all show the ashincreasing trends with the increasing particle size, while the ash of anthracitic coal samplesfrom Guizhou Liupanshui(LP) has a very small change and is nearly the same with the rawcoal samples. When one coal sample is grinding to different fineness, the changing trend ofthe size-ash curves is the same. Pulverized coals prepared by different type mill, the size-ashcurve changing with the coal samples. The grinding way has a large influence on the sizedistribution of mineral in pulverized coal.To research the influence of coal blending on mineral distribution of pulverized coalprepared by vibration mill, pulverized coal below15%fineness of the screen residue isprepared from the blended coal of the WB and DT, the WB and LP, the WB and YunnanXiaolongtan lignite (LT) with a5:5ratio. The results of industrial analysis on density fractionsof blended coal show that the preparation of different coal types leads to different yields withthe change of the densities. The ash content of each blended coals increases with the increaseof densities, while the volatile decreases. Average size of the pulverized coal in each densityfraction of blend coal of WB and DT, WB and LP decreases firstly and then increases.The research of effect of coal blending on the combustion characteristics shows that,with the same conditions of experiment and mixing proportion, the mixture of bituminouscoal and anthracite, the pre-grinding pulverized coal has a better combustion characteristicindex and comprehensive combustion performance than the pre-mixed pulverized coal exceptthe ignition characteristics. When bituminous coal is mixed with bituminous coal, the abovetwo mixing way have the approximate ignition characteristics and combustion characteristic.When bituminous coal is mixed with the lignite, the pre-mixed coal has a little bettercombustion performance than the coal mixed after grinding. The mixing way of bituminouscoal and anthracite has the most obvious influence on combustion. No matter which way tomix the coal, the bituminous coal mixed with the lignite has the best combustion reactionperformance followed by the bituminous coal mixed with bituminous coal, and thebituminous coal mixed with the anthracite coal has the worst performance. Combustion performance of the mixed coal that is grinded after mixed is greatly affected by the coal rank.The combustion characteristics of each size fraction of the bituminous coal andanthracite coal are studied by the thermogravimetry. The TG curve, ignition point, burning outtemperature, maximum weight loss rate and the corresponding temperature Tmax, conversionand conversion rate changing with temperature of different sieving granulation are analyzedand compared. With the same experimental conditions, the TG curve of the pulverizedbituminous move to the low temperature region when the sieved particle size decreases. Theignition point, burning embers performance, the combustion stability and the combustionreactivity of the pulverized coal and the overall combustion performance were improved. Inaddition, the smaller the size is, the more obvious the improvement is. Only the combustionTG curve of the pulverized coal of anthracite with small particle size moves to the lowtemperature region. The smaller the sieving granulation is, the better the ignition, thecombustion stability and the combustion reaction activity of pulverized coal are and the lowerthe temperature of burning embers is, but the degree of burn out is not always good when theparticle size is as small as possible. Bituminous coal has a greater influence of particle size onthe overall combustion performance of pulverized coal than the anthracite coal does.There are127figures,56tables and195literatures in the dissertation.更多还原