关键词: 木家具, 挥发性有机化合物, 传质特性, 完全解析模型, 测定方法

Abstract: Volatile organic compound(VOC)emission from wood furniture surface is a complex process of mass transfer with negative environmental effects.To have a clear picture of mass transfer characteristics, a new fully analytical model was established by using Laplace Transform, which comprehensively considered two key mechanisms of mass transfer(diffusion and convection), resistances of changing climate chamber concentration, background concentration and concentration of air inflow, and was applicable to simulating unventilated or ventilated condition, e.g.,predicting the concentration in climate chamber or furniture, evaluating the mass transfer rate or amount of emission and estimating the time for climate chamber concentration to reach an acceptable level.Then this model was analyzed to propose a convenient and rapid experimental method for simultaneously determining three significant mass transfer parameters of target VOC:emittable concentration ρ₀, diffusion coefficient δ and partition coefficient β, by making use of the process concentrations in a ventilated climate chamber.On one hand, a linear relationship was established between elapsed time and logarithm of difference between process concentration and equilibrium concentration, and its slope and intercept were the simple functions of δ and β.By data fitting and analysis, the slope and intercept were easily obtained as well as δ and β.On the other hand, a relationship was also established between β and ρ₀.Combined with the known β,ρ₀ could be easily further obtained too.In experiments,this method was used to study ρ₀, δ and β of formaldehyde and TVOC mass transfer from a piece of wood furniture made of medium density fiberboards, urea formaldehyde resin adhesive, veneer and polyurethane paint, which showed a coefficient of variation less than 5% between experimental results and calculation according to a reference treatment method by making use of mass transfer process concentration in an unventilated chamber, and effectively avoided potential troubles, such as negative pressure possibly caused by sampling in an unventilated chamber.The predicted results of climate chamber concentration in either unventilated or ventilated condition based on determined parameters and a numerical calculating model were in agreement with corresponding experimental data.In conclusion, both the proposed model and method are accurate enough to predict or determine mass transfer characteristics of VOC emission from wood furniture surface.

Key words: wood furniture, volatile organic compound(VOC), mass transfer characteristics, fully analytical model, determination method