A MULTISTAGE HYDROCYCLONE STIRRED-TANK SYSTEM FOR COUNTERCURRENT EXTRACTION OF CANOLA OIL

Ground canola seed containing 46.9% oil (A) and partially extracted meal, similar to pre-pressed meal containing 13.7% oil (B), were ground in a methanol/ammonia/water solution, filtered to remove antinutrients and extracted countercurrently with hexane in a multistage hydrocyclone/stirred-tank extraction unit. An empirical model was developed for predicting the yield (i.e., oil recovery) from the process. Based on the model calculations, a six-stage unit operating at a hexane-to-meal ratio (R) of 6.2 L/kg was required for processing meal A. The calculated oil recovery was 98.3%, resulting in a meal containing 0.7% residual oil. Meal B required a five-stage unit operating at R = 5.7 L/kg. The calculated oil recovery was 99.2% with 0.6% residual oil in the meal. The calculations were confirmed experimentally with two- and four-stage crosscurrent extraction processes.