Spent Bleaching Earth Treatment in a Pilot Scale Tubular Reactor using Subcritical Water Technology

Abstract

This work represents the extraction of oilsand free fatty acids from the spent bleaching earth using sub-critical water as a solvent in pilot scale batch reactors. Prior to using the pilot scale reactors, the extraction conditions were optimized using laboratory small batch reactor of 34 cm 3 volume. The optimization of the extraction condition showed that the optimum temperature, feed to solvent ratio, and extraction time were 270 °C, 1:3(the solvent is just water), 20 min. The obtained data were used to design tubularreactor with 7 Kg capacity heated with an electric heater. The extraction was carried out using 750 grams of the spent bleaching earth with 1:3 ratio. The results showed that more than 95% of the oil absorbed in the spent bleaching earth was recovered under 210 0 C. The heating up period was 72 minutes with holding extraction time of 20 minutes at 210 0 C and cooling down for 25 minutes.