Study On Bake Out Method Coupled With Intermittent Ventilation For Removing Indoor Noxious Gas

Recur to the volatile characteristic of chemical materials contained in building materials under high temperature, experts have brought forward traditional bake-out method which need to raise materials temperature to accelerate VOCs volatility. Compared with photic catalysis and absorption, this way maintains virtues like easy operation, high efficiency, low cost and so on. Traditional bake out method has been developed greatly in USA and Japan, and acquired great success in some practical building and offices. Nowadays in China, such investigations are still on an underway phase. On the basis of traditional bake out, bake-out method combining conventional bake-out with intermittent mechanical ventilation has been brought forward in this paper. Compared with traditional bake out, this new way banishes some disadvantage as follows: when temperature is too high in long time, building materials would be anamorphic and faded; it also would block chemicals to volatilize under high concentration.At first, on the basis of chamber test, this paper study removal effect of wood-based panel and decorated wood-based panel for different bake out way. By temperature accommodation, removal efficiency under different temperature has been studied. This paper analyzes formaldehyde, benzene, toluene, xylene concentration change and decrease ratio in all experimental course, and finally makes conclusion for removal efficiency of new bake out and traditional bake out.Secondly, on the basis of heat and mass transfer, several dry materials VOCs emission experienced model and theoretical model have been considered and one appropriate emission appropriate was chosen. By disdimension the model equation, emission coefficient equation is obtained and programmed into FLUENT boundary condition by UDF. This boundary condition is unsteady and it will be more reasonable for wood-base panel condition. On the basis of experiment study, numerical simulation use species transfer model to simulate indoor concentration change under different bake out time, ventilation mode. So that visible concentration chart and bake out time will be got. This help to apply new bake out method to remove indoor noxious gas effectively.