Abstract

Biomass material such as forest and agricultural residues are moist after harvest. Drying is an established operation to prepare them for pelletization. Wood pellet manufacturer involves drying wet biomass from mill residue or forest down to 5–7% wet-basis moisture content. Moisture reduction occurs conventionally in rotary drum dryers operating at high inlet temperatures of 300–600 °C. Although rotary dryers were initially designed to dry nonfibrous materials, these dryers have been used for drying grains, herbs, woody biomass, and agricultural wastes. Biomass materials have heterogeneous size, shape, and density properties, and their flow characteristics inside the drum are not a known phenomenon. This article reviews the researchers’ efforts to determine the residence time of solid material in concurrent rotary drum dryers. This review article analyzes the developed empirical correlations and solid cascading approximation to determine the residence time. The outputs of various empirical correlations are compared for a consistent operating condition.

摘要

森林和农业残留物等生物质材料在收获后是潮湿的。干燥是为造粒做准备的既定操作。木颗粒制造商涉及将来自磨机残渣或森林的湿生物质干燥至 5-7% 的湿基含水量。在 300–600 °C 的高入口温度下运行的转鼓式干燥机通常会减少水分。尽管回转式干燥机最初设计用于干燥非纤维材料，但这些干燥机已用于干燥谷物、草本植物、木质生物质和农业废弃物。生物质材料具有不均匀的尺寸、形状和密度特性，它们在滚筒内的流动特性是未知现象。本文回顾了研究人员为确定固体材料在并发转鼓干燥机中的停留时间所做的努力。这篇评论文章分析了开发的经验相关性和实体级联近似，以确定停留时间。针对一致的操作条件比较各种经验相关性的输出。