DEVELOPMENT OF COAL DRY BENEFICIATION WITH AIR-DENSE MEDIUM FLUIDIZED BED IN CHINA

来源 :中国颗粒学报(英文版) | 被引量 : 0次 | 上传用户:glory001
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
In China more than two-thirds of available coal reserves are in arid areas, where, to beneficiate the run-of-mine coal,there is not enough water resource required by conventional processing. Developing efficient dry beneficiation technology is of great significance for efficient coal utilization in China, notably the clean coal technology (CCT). The dry coal beneficiation technology with air-dense medium fluidized bed utilizes air-solid suspension as beneficiating medium whose density is consistent for beneficiation, similar in principle to the wet dense medium beneficiation using liquid-solid suspension as separating medium. The heavy portion in feedstock whose density is higher than the density of the fluidized bed will sink, whereas the lighter portion will float, thus stratifying the feed materials according to their density.In order to obtain efficient dry separation in air-dense medium fluidized bed, stable fluidization with well dispersed micro-bubbles must be achieved to ensure low viscosity and high fluidity. The pure buoyancy of beneficiation materials plays a main role in fluidized bed, and the displaced distribution effect should be restrained. The displaced distribution effects include viscosity displaced distribution effect and movement displaced distribution effect. The former is caused by viscosity of the fluidized bed. It decreases with increasing air flow velocity. Movement displaced distribution effect will be large when air flow rate is too low or too high. If medium particle size distribution and air flow are well controlled, both displaced distribution effects could be controlled effectively. A beneficiation displaced distribution model may be used to optimize beneficiation of feedstock with a wide particle size distribution and multiple components in the fluidized bed. The rheological characteristics of fluidized beds were studied using the falling sphere method. Experimental results indicated that the fluidized bed behaves as a Bingham fluid. The plastic viscosity and yield stress can be obtained by measurement of the terminal settling velocity of spheres and linear regression of the experimental data. Both plastic viscosity and yield stress increase with increasing size of the fluidized particles. The drag coefficient can be calculated with favorable agreement with experimental data.The first dry coal beneficiation plant with air-dense medium fluidized bed was established by CUMT with an output of 320000 t.a-1 and a probable error Ep value up to 0.05 was achieved. The plant was accepted by the Chinese government in June, 1994. Since then, new applications have been found including a 700000 t.a-1 dry coal beneficiation plant put up for commercial testing. To realize coal dry beneficiation of full size range of 300~0 mm, further research on dry coal beneficiation of different size fractions has been under way at the Mineral Processing Research Center of CUMT, leading to the following results:● Dry beneficiation technology with a vibrated air-dense medium fluidized bed for fine coal of size fraction 6~0.5 mm Ash content was reduced from 16.57% to 8.35%, with yield up to 80.20% and Ep value up to 0.065.● Coal dry beneficiation technology with a deep air-dense medium fluidized bed for >50 mm coal An Ep value up to 0.02 was achieved. This technology is of great value for waste removal from 300~50 mm large feedstock, especially for big surface mines in China.● Coal triboelectric cleaning technology for <1 mm pulverized Coal Coal is comminuted down to 320 mesh (0.043 mm) to fully liberate the embedded minerals, yielding an ultra-low ash coal (less than 2%). Currently a pilot system with triboelectric cleaning has successfully passed technical appraisal.● Three-product beneficiation technology with dual-density fluidized bedThis technology yields three products: clean coal, middling and tailing, with the following typical results: Ep value of 0.06~0.09 for the upper layer with a density of 1.5~1.54 g.cm-3 and Ep value of 0.09~0.11 for the lower layer with density of 1.84~1.9 g.cm-3.
其他文献
提出了利用受激布里渊散射的阈值效应主动在非配合、扩展目标上实现小面积信标的方法,在不同的大气扰动条件(C2n=10-16~10-12)下,对激光的远距离(10km)补偿传输过程进行了模拟
重点开展了稳态、瞬态X射线辐照引起的金属 氧化物 半导体 (CMOS)器件剂量增强效应relativedoseenhance menteffect(RDEF)研究 .通过实验给出辐照敏感参数随总剂量的变化关
通过金属钼粉与过氧化氢溶液反应制备三氧化钼溶胶和凝胶,在高压汞灯的照射下,溶胶和凝胶由浅黄色变成蓝色.Raman光谱研究表明:通过紫外光照,MoO3凝胶结构进行了重整,呈有序
本文报道了利用超瑞利散射 (HRS)技术研究 7-羟基喹啉 (7HQ)的二阶非线性光学性质。采用波长为 10 6 4 nm、脉冲宽度为 35 ps的激光作激发光 ,观测其超散射光强与入射光强的
在神光Ⅱ基频光直接驱动内爆实验中,利用CR39径迹探测器测量了DT靶丸释放出的14MeV中子弹性散射后逃逸出燃料的反冲D核和反冲T核的数量,实现了激光聚变实验中燃料面密度〈ρR
The multi-scale structures of complex flows in chemical engineering have been great challenges to the design and scaling of such systems, and multi-scale modeli
用室温固相反应法合成了三种具有非线性光学性质的二茂铁-多金属氧酸盐电荷转移配合物[Fe-(C5H5)2H]3PW12O40(Ⅰ),[Fe(C5H5)2H]4SiW12O40(Ⅱ)和[Fe(C5H5)2H]4GeW12O40(Ⅲ).用
采用量子化学ab initio(4-31G基组)方法,计算了NH3复合分子(H3N…H+…NH3)中的质子转移势能,氢键长度和取向的变化都没有影响它的双势阱特征,长度越长、分子主轴偏离氢键键轴
采用离子注入方法制备β- Fe Si2 薄膜 ,选择 C作为掺杂元素 ,得到了β- Fe Si2 硅化物层与基体间的界面平直、厚度均一的高质量薄膜 .经透射电镜分析可知 ,引入 C离子后硅化
用密度泛函理论方法研究了O(3P)与O2H反应生成羟基和氧分子的反应机理. 在PW91/6-31+G水平上用梯度解析技术全自由度优化上述反应物、产物和反应路径上的中间体及过渡态几