Thermodynamic analysis of a novel wood drying system based on self-heat recuperation technology

Abstract

ABSTRACT The issue of energy consumption in the field of wood drying has attracted widespread concern worldwide. In this paper, combining with the self-heat recuperation technology, a novel self-heat recuperation wood drying system (SHRWDS) with a fixed bed dryer is proposed to recover the sensible heat and latent heat of humid air, which is not fully utilized in the general drying process of wood. Mathematical models of the SHRWDS based on the conservation of mass and energy are established, and the effects of drying temperature, airspeed, and compression ratio on the energy and exergy input as well as the economy of the whole system are also carried out. The simulation results show that the drying temperature and the airspeed have a positive influence on the system performance, with optimal values, while the effect of the compression ratio is closely related to the relative humidity of the humid air at the outlet of the dryer. Furthermore, the minimum energy input of 77.23 kJ/s and exergy input of 28.27 kJ/s for the system are obtained at the condition of t= 60°C, v= 1.5 m/s, and φ= 90%, while the minimum annual consumption of standard coal volume and the lowest cost of wood drying for the SHRWDS are 68.34 t and 16.54 $/t. All of this indicates the remarkable superiority of the presented system compared with the traditional device.