Impact of relative humidity on a nanostructured filter cake - Experimental and modelling approaches

•Pressure drop and thickness variations of a humid nanostructured deposit are presented.•An equation allowing porosity determination for a humid nanostructured deposit is proposed.•The porosity equation was implemented in two pressure drop models.•A good match between modelled and experimental results was found.

In this paper, three different non-hygroscopic nanostructured powders were dispersed in dry air and filtered to create a nanostructured deposit. The relative humidity was then gradually increased from 0 to 85% and the thickness of the deposit continuously measured using a laser trigonometry device. Experimental results showed that for each sample, the pressure drop of the deposit increases when the relative humidity increases, while the bed thickness decreases.The modelling of the pressure drop upon increasing humidity was conducted using two pressure drop models available in the literature and specifically developed for nanostructured deposits. The variations in porosity and in cake thickness were included in the pressure drop models. This was achieved using a semi-predictive model of adsorption-condensation on nanoparticle beds developed to calculate the water mass sorbed by a powder. The modified models represent the experimental results with a maximum deviation of 10%.