Increase of the emission of CO2, which is mostly the result of the combusted fossil
fuels into the atmosphere, exponentially increases. Through increased energy efficiency there is
lower CO2 emission. There is a tendency to reduce exhaust gases temperatures down from their
original value referred to as “acid dew point”, 115-160°C. A result is vapor condensation of wet
flue in chimney. Condensation occurs when the surface temperature is below the dew point of the
vapor-gas mixture. Therefore, Vapor-Liquid Equilibrium models are required in order to determine
the dew point of the mixture. Wet flue gas is simulated with vapor-air mixture. A numerical model
was presented to calculate the velocity and thermal field of turbulent vapor-air mixture flow trough
a chimney. The momentum and temperature field were calculated via a finite-volume CFD code,
using the k – e turbulence model. The validation of this calculation was conducted employing an
experimental set for heat and mass transfer in vertical upward vapor-air mixture. Measurements
were done using a stainless steel tube of 13.2 mm I.D. (internal diameter) and 70 I.D. lengths. Flow
rates of steam and air were varied as the experimental parameters.
The experiment involves two-phase, two-component, heat and mass transfer. Comparisons of wall
temperature and condensate rate were made and the model was shown to give an acceptable results.
An Experimental Investigation of Water Vapor Condensation from Biofuel Flue Gas in a Model of Condenser, (1) Base Case: Local Heat Transfer without Water Injection