萃取对准东煤金属脱除及其燃烧特性的影响

Effect of extraction treatment on metal removal and combustion characteristics of Zhundong coal

为了降低碱金属含量对燃准东煤锅炉结渣、沾污的影响,在分析准东煤主要金属赋存形态的基础上,研究了水浴和微波水热处理方式下,水、醋酸铵、醋酸-醋酸铵混合溶液和醋酸-双氧水混合溶液对准东煤金属元素脱除规律及其燃烧特性的影响。研究表明:水浴加热时,去离子水对准东煤中钠脱除率为43.1%,对钙、镁、铁脱除率较少;醋酸-双氧水混合溶液对钠脱除率高达90.1%,铁脱除率达到31.9%。与水浴20 h相比,微波加热15 min处理对煤中主要金属脱除率相近。去离子水萃取处理后,煤样着火温度、燃尽温度均降低,燃烧特性得到改善;而采用醋酸铵溶液和醋酸-双氧水混合溶液萃取时,煤样燃烧特性变差。4种萃取溶液萃取后,煤样燃尽剩余量均由8.20%降至2.91%~4.27%。

In order to mitigate the influence of alkali metals amount on the slagging and the fouling for the Zhundong coal-fired boil, the effect of hydrothermal treatments （ Water bath and Microwave assistant water bath ） and extraction solutions （ Water, Ammonium acetate, ammonium acetate/acetic acid mixture, acetic acid/hydrogen peroxide mixture） on the removal of alkali metals and combustion characteristics of Zhundong coal were investigated. The results indicate that the removal of sodium is 43.1% after treating with water under water bath; while the reducing of calcium, magnesium and iron are less than that of sodium. Compared to water, the mixture solution of acetic acid and hydrogen peroxide could remove 90.1% of sodium and 31.9% iron under water bath. The microwave irradiation could achieve similar re- moval rate of metals within 15 min compared with the traditional hydrothermal treatment for about 20 h. Both the ignition temperature and the burnout temperature of Zhundong coal are decreased after the extraction of water ; while its combustion characteristics is improved. However, the combustion characteristics of Zhundong coal turns worse after the extraction by ammonium acetate or the mixture solution of acetic acid and hydrogen peroxide. And the solid residue of coal after burning out decreases from 8.21% to about 2.91% -4.27 % after extracted by these four solutions.