Author/Authors :
Ghodbanan، SH نويسنده Chemical Engineering Faculty, Sahand University of Technology, Tabriz, Iran , , Alizadeh، R نويسنده Chemical Engineering Faculty, Sahand University of Technology, Tabriz, Iran , , Shafiei، S نويسنده Chemical Engineering Faculty, Sahand University of Technology, Tabriz, Iran ,
Abstract :
In this study a developed model has been used to evaluate the
paper drying process and examine the pocket dryer conditions of a
multi-cylinder fluting paper machine. The model has been
developed based on the mass and energy balance relationships in
which the heat of sorption and its variations with paper
temperature and humidity changes have been taken into account.
The applied model can be used to compute the drying parameters
and analyze the pocket drying conditions. Furthermore, the effects
of web tension on the heat transfer have been investigated. In the
available operating range of the web tension, the overall mean
heat transfer coefficient will be within 300-550 W/m2.K. The
pocket air temperature was between 50 and 90oC. The dew point
temperature was not close to the pocket air temperature and dew
drop never happened during the dryer section.
Based on the modeling result and using a novel technique, the
maximum level for the exhaust air in the studied machine can be
estimated to be 0.2 kg H2O/kg dry air. Result shows that increasing
the exhaust humidity to the optimal level will lead to 4% reduction
in the required energy and 20% rise in the heat recovery potential.
Accordingly the specific heat consumption per evaporated water
for the studied drying section can be reduced from 3.96 to 3.81 GJ
per ton water.
