洗煤对高碱煤碱金属迁移及灰熔融特性的影响  

Influence of Coal Washing on the Metal Migration and Ash Fusion Characteristics of Coal With a High Alkali Content

作　　者：代百乾[1] 乌晓江[1] 张忠孝[1] 

机构地区：[1]上海理工大学,上海200093

出　　处：《热能动力工程》2014年第1期76-80,110,共5页Journal of Engineering for Thermal Energy and Power

基　　金：国家自然科学基金项目(51276212);上海高校青年教师培养资助计划(slg11024))

摘　　要：针对燃用某高碱煤种遇到的强沾污、结渣难题，对典型高碱煤种分别用去离子水、1mol／L硝酸和1mol／L醋酸铵进行了洗煤，并用电感耦合等离子体发射光谱仪（ICP—OES）、X射线荧光仪（XRF）、和X射线衍射仪（XRD）等分析测试仪器对不同溶剂洗煤前后煤中的碱金属元素、矿物质组成进行了分析与测试。研究结果表明：3种洗煤介质对煤中Al和Si几乎没有脱除效果。但去离子水对煤中Na、K、S、Fe的脱除率在50％左右；硝酸和醋酸铵能对煤中Ca和Na的脱除率达到90％左右；洗煤后煤灰的熔融温度虽然变化不大（DT升高11～42℃），但洗煤后由于Na、S等碱金属的脱除，使得在灰的熔融过程中，初始液相析出温度由原煤的700℃升至900℃（硝酸）和1100℃（醋酸铵）：且初始液相析出的质量百分比也由17wt％降低至5．38wt％（去离子水）／5．09wt％（硝酸），这对降低高碱煤的沾污程度起着至关重要的作用。In the light of such difficulties encountered in burning a coal rank with a high alkali content as excessively more fouling and slagging,a typical coal rank was chosen to perform coal washing by using deionised water,1 mol / L nitric acid and 1 mol / L ammonium acetate respectively and an ICP-OES( induction coupled plasma object emission spectrometer),XRF( X-ray fluorescence) and XRD( X-ray diffraction) meter etc. analyzer and instruments to conduct an analysis and testing of the alkali metal elements and mineral substance components of coal before and after coal washing by using various solvents. The research results show that the above-mentioned three kinds of solvents for coal washing have almost no removal effectiveness to Ca and Si in coal while the deionised water has an around50% removal rate of Na,K,S and Fe in coal. The nitric acid and ammonia acetate can attain an about 90% removal rate of Ca and Na in coal. Albeit the fusion temperature of the coal ash after coal washing has no big change( a deformation temperature of the ash increases by 11 to 42 ℃). However,due to the removal of Na and S etc. alkali metals after the coal washing,the precipitation temperature of the initial liquid phase in the ash fusion process will increase from 700 ℃,if raw coal is used,to 900 ℃( nitric acid) and 1 100 ℃( ammonium acetate) and the mass percentage of the initial liquid phase precipitated will also decrease from 17 wt / % to 5. 38wt%( deionised water) /5. 09wt%( nitric acid). This plays a vitally important role in reducing the fouling degree caused by burning coal with a high alkali content.

关 键 词：高碱煤 洗煤 碱金属 熔融特性 迁移 

分 类 号：TQ325.5[化学工程—合成树脂塑料工业]