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

摘要： 木家具表面挥发性污染物的散发是一类污染环境的复杂传质行为。为准确把握传质特性,首先建立了一套更完善的新式完全解析模型,综合考虑了两大传质机理(扩散、对流)、气候箱中污染物阻力、背景浓度和进气浓度,同时适用于无换气或换气条件下的模拟研究;例如,预测气候箱或木家具中污染物浓度变化,评价传质速率或散发量,以及估算室内浓度达标时限。然后通过对模型的分析提出了一套简便快捷的新式实验法,利用木家具在换气箱中散发的逐时浓度,一并求取目标污染物的3个重要传质参数:可散发量ρ₀、扩散系数δ和分配系数β。实验部分使用该换气箱法测算了某密度板家具中甲醛和总挥发性有机化合物的ρ₀、δ和β,与文献中基于密封箱的数据处理方法所得结果的变异系数小于5%,并有效避免了出现负压等密封箱采样可能导致的潜在问题。将传质参数代入数值算法预测了密封箱和换气箱中木家具散发挥发性污染物的浓度变化,与实验测量的数据吻合良好。该模型和方法能够准确预测或测定木家具表面挥发性污染物传质特性。

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