褐煤脱水及水质净化研究

Study on the lignite dehydration technology and purification recycling

为实现褐煤提质并缓解褐煤产区缺水现状,采用微波及水热脱水方法对褐煤进行脱水改性并回收褐煤所脱水分.通过检测水分化学需氧量、氨氮、总磷、硬度、离子、有机化合物等各项指标,对褐煤中水分进行深入分析,并比较两种脱水方法的脱水、净化效果.结果表明微波方式脱水率可达70%∽80%,除化学需氧量外,其它水质指标均符合工业用水标准,且杂质含量随微波功率增加而降低,利于净化回收.水热方式可有效改善褐煤煤质,脱水率最高可达87.44%,但各项水质指标均大大超出标准范围,且杂质含量在250℃工况下达到最大.两种冷凝水均检测到微量有毒金属元素、有毒致癌的多环芳烃及酚类化合物,将成为后续净化的主要脱除对象.

The microwave dehydration and hydrothermal dewatering methods were used to modify lignite and recycle the generated water. By measuring the chemical oxygen demand, ammonia nitrogen, total phosphorus, hardness, ions and organic compounds of lignite, the results show that the dehydration ratio of microwave method reaches 70%∽80%, and the water quality can meet the industrial standard except for the chemical oxygen demand. And the dehydration ratio of hydrothermal method is about 87.44%, but the water quality can not meet the industrial standard. Therefore, the generated water from lignite by microwave dehydration is much ＂cleaner＂ than that by hydrothermal dewatering. In significant amount of poisonous metal elements and organic compounds are in the condensed water, which will be considered during the next step of purification process.