Drying characteristics of willow chips and stems

• Published in: Journal of agricultural engineering research 2000, Vol.77 (4), p.391-400
• Main Authors: Gigler, J.K, Loon, W.K.P. van, Seres, I, Meerdink, G, Coumans, W.J
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; ALMACENAMIENTO; Applied sciences; APTITUD PARA LA CONSERVACION; APTITUDE A LA CONSERVATION; ASTILLAS; Biological and medical sciences; CHIPPING; COSECHA; DRYING METHODS; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; HARVESTING; Harvesting. Postharvest. Storage; KEEPING QUALITY; Leerstoelgroep Meet-, regel- en systeemtechniek; Mechanical woodworking and drying; MODELE; MODELOS; PARTICULE DE BOIS; Polymer industry, paints, wood; POSTHARVEST TECHNOLOGY; PROCESAMIENTO; PROCESSING; RECOLTE; SALIX VIMINALIS; STOCKAGE; STORAGE; Systems and Control Group; TECHNOLOGIE; TECHNOLOGIE APRES RECOLTE; TECHNOLOGY; TECNOLOGIA; TECNOLOGIA POSTCOSECHA; TRAITEMENT; Vegetative propagation. Sowing and planting. Harvesting; VLAG; Wood; WOOD CHIPS; Wood. Paper. Non wovens
• ISSN: 0021-8634; 1095-9246
• DOI: 10.1006/jaer.2000.0590

In supply chains of willow (Salix viminalis) biomass to energy plants, drying is advisable in order to enable safe long-term storage, increase boiler efficiency and reduce gaseous emissions. To gain insight into the drying process, drying characteristics of willow chips and stems were investigated experimentally in a drying installation. The drying process was modelled with a diffusion equation. The effective water diffusivity Deffwas assumed to be a simple algebraic function of the dimensionless moisture concentration m:Deff =D0ma, with D0being the initial diffusivity, and a an empirical exponent. Drying of a chip and of a stem without bark could be successfully described with a diffusion equation for a plane sheet and a cylinder, respectively. Drying of a stem with bark could be successfully described as drying of a stem without bark surrounded by a thin layer (bark) with a much lower diffusivity. Compared to a chip, a stem without bark dried approximately 10 times slower from fresh state to equilibrium moisture content, mainly due to the larger diffusion distance of the stem. A stem with bark dried approximately 10 times slower than a stem without bark due to the low diffusivity of the bark.