Sodium polyacrylate hydrogel fixed bed to treat Water-Contaminated cloudy diesel

Abstract

The applications of hydrogels in industry and academia are numerous and well known. However, the use of these cross-linked polymer materials is presented in this article with a particular purpose that is unexplored in the literature: to reduce water content from diesel aiming at meeting commercial specifications for turbidity in a continuous process. Currently, there are different processes in the industry to reduce water content in fuels, such as coalescing filters (for non-soluble water) and distillation (with high energy demand). However, this work showed the potential application of hydrogel as an alternative technology, being able to remove soluble water with ease of installation and low energy consumption. Sodium polyacrylate (SPA) hydrogel was chosen among others - polyacrylamide (PAAm) and poly(acrylic acid) (PAA) hydrogels - to treat cloudy diesel in a fixed bed. This polymer was characterized in terms of morphology and chemical composition and the swelling degree kinetics was studied considering different lyophilisation conditions and particle diameters. Also, the effect of type of external media and temperature on the equilibrium swelling degree were assessed. The lyophilized SPA hydrogel reduced the water content of diesel from around 630 ppm to near 100 ppm and the turbidity from Haze 6 down to Haze 1. These results demonstrate that the new technology has a potential use in petroleum refineries, storage and distribution facilities and also in small scale applications, such as in gas stations.