Audrey Villot

Numerical Model of Current–Voltage Curve for the Wire-Cylinder Electrostatic Precipitators in Negative Voltage in the Presence of Nonpolar Gases

The aim of this paper is to develop a numerical model that takes into account the share of the electric current produced by free electrons when an electrostatic precipitator (ESP) with a wire-cylinder geometry is supplied with a negative voltage and the carrier gas is nonpolar. This model improves the understanding of ESPs and highlights the parameters that affect the process behavior and the generation of free electrons. It takes into account the current stemming from the presence of free electrons. For this reason, a coefficient was developed and was expressed as a function of the temperature, pressure, and composition of the carrier gas. Experimental results obtained by other authors and laboratory measurements were compared with the model. The set of results showed that the numerical model developed in this paper is valid only in the presence of nonpolar gases.

Sustainable conversion of agriculture wastes into activated carbons: energy balance and arsenic removal from water

ABSTRACT The aims of this study are to investigate the production of activated carbons (AC) from Senegal agricultural wastes such as cashew shells, millet stalks and rice husks and to implement them in adsorption processes devoted to arsenic (V) removal. AC were produced by a direct physical activation with water steam without other chemicals. This production of AC has also led to co-products (gas and bio-oil) which have been characterized in terms of physical, chemical and thermodynamical properties for energy recovery. Considering the arsenic adsorption results and the energy balance for the three studied biomasses, the first results have shown that the millet stalks seem to be more interesting for arsenate removal from natural water and an energy recovery with a GEEelec of 18.9%. Cashew shells, which have shown the best energy recovery (34.3%), are not suitable for arsenate removal. This global approach is original and contributes to a recycling of biowastes with a joint recovery of energy and material.