褐煤干燥水分回收利用及其研究进展

褐煤干燥提质过程中的水资源化回收利用工艺技术可以提高煤阶并回收宝贵的水资源,降低干燥提质单元能耗。本文从介绍褐煤中水的存在形态出发,围绕烟气直接干燥、蒸汽流化床干燥、微波干燥、机械热压脱水干燥等工艺综述了近年来干燥水回收利用的研究现状和最新进展,讨论分析了褐煤干燥与水回收利用工艺的选择原则。在回收褐煤中丰富的水资源时,除了单纯考虑回收褐煤中的水资源,还应权衡褐煤干燥工艺、干燥温度和干燥介质、干燥水蒸气的余热利用方式以及干燥工艺上下游间的衔接等因素。基于目前褐煤资源的主要用途,将干燥尾气采用换热技术回收低温余热和干燥冷凝水直接净化处理后的二次回用技术将是以后的重要研究和应用方向。

Recent developments in recovery and utilization of water and heat from lignite dewatering

Lignite dewatering based on recovery of water and heat can significantly reduce water and energy consumption in the drying unit. The existence states of water in lignite are introduced,and the advances in recovery and utilization of water and heat from lignite dewatering are reviewed. Specially,drying technologies in the light of drying with flue gas,drying in fluidized bed with steam,microwave drying and mechanical/thermal pressurizing are presented. The principle for selection of lignite dewatering process and water recovery system is discussed. During recovery of water resource,considerations of lignite dewatering process,drying temperature,drying medium,heat recovery technology,and linkages of various processes should also be included. The process,which integrates heat exchangeand water purification into lignite dewatering would be a promising research and application topic in the future.