Effect of Vibration during Compression on the Process of Making Biomass Briquettes

An attempt to introduce assistive vibration into the process of biomass briquetting was carried out, with a focus on lowering the energy requirement and improving product quality. The effects of assistive vibration on the surface morphology of briquettes using corn stalk and wheat straw as the experimental materials was investigated, and it was found that assistive vibration can increase the flow capacity of the material and improve the press transmission as well as the uniformity of internal stresses to facilitate the inner-layer-material compression and lower the springback of the compressed material. The biomass particles were still bonded primarily by mechanical interlocking and solid bridges, but the distribution range and size of the voids or gaps between adjacent particles were reduced, and the particles or fibers of thicker layer appeared to be "lying down" instead of "standing," indicating a higher density of the product compared with the case of compaction without vibration assistance.