Determination of the heat energy for hydrothermal treatment of ashwood (Fraxinus excelsior) by log soaking
Date Issued
2023-09
Author(s)
Abstract
The treatment of logs by soaking is a complex technological and thermal procedure, in which logs
and prisms are used as raw material for the production of peeled and sliced veneers. Such treatment of
logs is carried out in pools or pits constructed in the ground. By log soaking two significant changes to
the wood are achieved, its coloring and the inevitable plastification of the wood fibers. During this
procedure, the time required for air drying is significantly reduced. The soaking medium is fresh water
or previously used water at an elevated temperature. This soaking treatment is particularly suitable for
logs for the production of peeled and sliced veneer, from which resin must be removed. Soaking is
also used when treating wood species that are sensitive to steaming.
This paper provides an analysis of the thermal energy required for hydrothermal treatment by log
soaking of ashwood (Fraxinus excelsior). The logs were intended for the production of peeled veneer.
The log treatment was done in a reinforced concrete pool built in the ground. The total amount of heat
for log soaking (Q) consists of effective heat (Qpv) and heat loss (Qzv). The procedure was conducted
by the strong treatment mode, with a temperature interval in the range of 70 to 90 °C. The treated logs
had a minimum mean diameter of 35,0 cm and a minimum length of 1,8 m. Log soaking was used as a
method for defrosting of the logs, due to their low initial temperature, which was– 15 °C.
and prisms are used as raw material for the production of peeled and sliced veneers. Such treatment of
logs is carried out in pools or pits constructed in the ground. By log soaking two significant changes to
the wood are achieved, its coloring and the inevitable plastification of the wood fibers. During this
procedure, the time required for air drying is significantly reduced. The soaking medium is fresh water
or previously used water at an elevated temperature. This soaking treatment is particularly suitable for
logs for the production of peeled and sliced veneer, from which resin must be removed. Soaking is
also used when treating wood species that are sensitive to steaming.
This paper provides an analysis of the thermal energy required for hydrothermal treatment by log
soaking of ashwood (Fraxinus excelsior). The logs were intended for the production of peeled veneer.
The log treatment was done in a reinforced concrete pool built in the ground. The total amount of heat
for log soaking (Q) consists of effective heat (Qpv) and heat loss (Qzv). The procedure was conducted
by the strong treatment mode, with a temperature interval in the range of 70 to 90 °C. The treated logs
had a minimum mean diameter of 35,0 cm and a minimum length of 1,8 m. Log soaking was used as a
method for defrosting of the logs, due to their low initial temperature, which was– 15 °C.