Experimental design and response surface methodology applied to the dielectric properties of hydroalcoholic solutions containing sodium chloride

Anderson Dos Santos Morais,Carlos Henrique Ataíde,João Jorge Ribeiro Damasceno

doi:10.1590/1981-6723.08517

Anderson Dos Santos Morais, Carlos Henrique Ataíde + Show 1 more

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https://doi.org/10.1590/1981-6723.08517

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Abstract

Abstract The main focus of this study was to use an experimental design to and the response surface statistical technique to predict and optimize the dielectric properties of hydrated ethanol-sodium chloride blends. Several samples of these blends were prepared considering the following variables: hydrated ethyl alcohol concentration, sodium chloride concentration and temperature. The main dielectric properties of these blends, i.e., the dielectric constant, dielectric loss factor and dissipation factor, were measured in a calibrated device suitable for liquid or pasty substances. For this study, experimental tests were carried out according to a Central Composite Design (CCD). Response surface techniques were used to predict the magnitude of the effect of the input variables on the responses investigated, particularly on the dissipation factor. This factor represents the ability of the substance to convert electromagnetic energy into heat. Within the experimental range studied here, the values of the variables that optimized the response were as follows: sodium chloride concentration of 2.21%, hydrated ethanol concentration of 4.64% and temperature of 87 °C.

Highlights

The productive capacity and sustainable development of the Brazilian sugar and ethanol industry have aroused strong interest worldwide, since this is the first economy that has achieved the sustainable use of biofuels.These days, sugarcane alcohol is recognized worldwide for its environmental and socioeconomic advantages, and first world countries are interested in this technology
The influence of the variables: x sodium chloride concentration (%) – C ; NaCl x2, ethanol concentration (%) – CEtOH, and x3, temperature (°C) – T on the dielectric properties ε”, ε’ and tgδ were studied according to a central composite design with three replicates at the centre, giving a total of 17 experiments
We found that, within the interval of ethanol concentrations investigated, the properties that define the ability of the material to convert electromagnetic energy into heat were not affected by microwave heating

Summary

Introduction

The productive capacity and sustainable development of the Brazilian sugar and ethanol industry have aroused strong interest worldwide, since this is the first economy that has achieved the sustainable use of biofuels. These days, sugarcane alcohol is recognized worldwide for its environmental and socioeconomic advantages, and first world countries are interested in this technology. The growing demand for ethanol and the increasing competitiveness of the current world market are driving researchers and companies operating in the sector to seek high productivity processes allied to lower operating costs, e.g., energy consumption during the heating of the fermented sugarcane juice in the distillation operation. Experts have warned that efficiency gains in commodity production are predominant factors for competitiveness on world markets (BICALHO et al, 2012)

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