(417g) Recovery of Organic Solvents from Vegetable Oil Streams

Membrane separation is increasingly used for the processing of organic solvents systems. Apart from targeting at very specific separations, such membranes are suitable for upgrading of solvent recovery. In current industry, a combination of membrane technology and distillation/evaporation is the most relevant.

Currently used distillation/evaporation is expensive (energy) and sometimes introduces degradation of products (lowering quality). Less heat input in the products by using membranes should improve continuous quality at lower costs. But when solvent is recovered with membranes the throughput of the membrane is not constant-due to concentration polarization and fouling. This leads to a point where membranes are less effective. In a constellation of membrane and evaporation this means that there are optimal conditions â??for membranes in technical sense and for the process for the overall economics.

We have modeled and experimented a few systems to explore the optimal regimes. In this area membrane permeation and separation as well as ease of evaporation and energy costs play a role. Solsep has also experimented with systems that can handle high viscosity feeds and promise relatively high and well-defined mass-transfer properties. This could shift the optimal point to less evaporation. For eg acetone-veggy oil streams it has been found that membranes can be extremely attractive giving well-defined product quality with decreased costs. Enviroment-friendliness and low space needed is also an attractive feature.

Advantage (over current membrane systems)

-robust in organic solvents (here proposed: methylene chloride, acetone, toluene)

-also designed for high viscosity

Advantage over currently used technology (evaporation):

-low temperature, low(er) energy costs

-better product quality

-adaptable to current technology (evaporation, â??flashingâ?)-hybrid

-less or other fouling that may be better controllable (also evaporation has fouling)

We will discuss work on the removal of solvents and possible use in processing of oils and fats industry. A special pilot is on acetone recovery from seed oil fractionation plan has been built. On this system extensive piloting is done and still in progress.