Debarking enhancement of frozen logs. II. Infrared system for heating logs prior to debarking.

摘要

Log volume losses, remaining bark on logs after debarking, and bark content in wood chips are significantly higher in winter than in summer for northern sawmills. It is, therefore, beneficial to raise the temperature of the log prior to debarking. Heating logs before debarking in the winter could generate an estimated savings of up to half a million Canadian dollars for a sawmill processing half a million cubic meters of wood annually. In the past, sawmills used water soaking to thaw logs, but most have stopped this practice due to new environmental regulations that increase water treatment costs. The goal of the project described in this paper was to demonstrate, on a semi-industrial prototype, the applicability of using infrared radiation to preheat black spruce logs. The main objectives were to evaluate specific energy consumption and the profitability of the technology. If all of the economic considerations of bark content in woodchips for the pulp and papermill are considered, the return on investment of an infrared system to preheat frozen logs is believed to be less than 1 year.