ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Drying characteristics of willow chips and stems.

Gigler, J. K.; Loon, W. K. P. van; Seres, I.; Meerdink, G.; Coumans, W. J.;

Journal of Agricultural Engineering Research Year: 2000 Vol: 77 Issue: 4 Pages: 391-400 Ref: 33 ref.

2000

บทคัดย่อ

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 Deff was assumed to be a simple algebraic function of the dimensionless moisture concentration m: Deff=Do ma, with Do being 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 approx equal to 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 approx equal to 10 times slower than a stem without bark due to the low diffusivity of the bark.