Abstract:

Naomaohu raw coal and washed coal were pyrolyzed in a vertical tube furnace. By means of inductively coupled plasma-atomic emission spectrometry (ICP-AES) and X-ray diffraction (XRD), the precipitation characteristics of alkali metal sodium and the migration and transformation rules between different deposit forms of Naomaohu coal at different pyrolysis temperatures were studied. The results show that in the pyrolysis process of ammonium acetate washed coal and hydrochloric acid washed coal, insoluble sodium are converted to ammonium acetate soluble sodium and acid soluble sodium, in which the volatility of sodium shows an increasing trend with the release amount of 3%—24%; while during the pyrolysis process of water washed coal, sodium migrates and transforms from water-soluble, ammonium acetate-soluble and acid-soluble states to insoluble and gaseous phases. Sodium in raw coal is mainly water-soluble. In the pyrolysis process, water-soluble sodium transforms into other forms, in which the volatility of sodium first decreases and then increases, reaching the lowest at 600℃. At low temperature, the sodium volatilization comes from the decomposition of ammonium acetate soluble sodium. At high temperature, water soluble sodium and acid soluble sodium enter the gas phase, which makes the sodium volatilization rate of raw coal and washed coal increase at 800℃.

Key words: Naomaohu coal, pyrolysis, sodium, washing coal, migration and transformation

摘要：

采用立式管式炉对淖毛湖原煤和洗煤进行热解，利用电感耦合等离子体-原子发射光谱（ICP-AES）、X射线衍射（XRD）等检测手段研究了淖毛湖煤在不同热解温度下碱金属钠的析出特性及不同赋存形态之间的迁移转化规律。结果表明：乙酸铵洗煤和盐酸洗煤的不溶钠在热解过程中会向乙酸铵溶钠和酸溶钠转化，其中钠的挥发性呈现增加的趋势，释放量在3%～24%；而水洗煤在热解过程中钠会从水溶态、乙酸铵溶态和酸溶态向不溶态和气相迁移转化。原煤中钠主要以水溶态为主，在热解过程中水溶钠会向其他形态转化，其中钠的挥发性先减少后增加，在600℃达到最低。低温下钠的挥发来自乙酸铵溶钠的分解，高温下水溶钠和酸溶钠会进入气相，使得原煤和洗煤在800℃时钠的挥发速率增加。

关键词: 淖毛湖煤, 热解, 钠, 洗煤, 迁移转化