Supercritical carbon dioxide extraction of oil from fixed beds (4.8 mm, 24.5 and 12.7 mm I.D.) of crushed canola seeds is described. Experiments were performed to obtain equilibrium data and extraction rates at 55 C, 36 MPa using solvent velocities ranging from 0.04 to 2.8 mm/s. A one‐dimensional, unsteady state mathematical model was used to obtain the oil concentration profiles in both the solvent and solid phases, and to determine the overall volumetric mass transfer coefficients. The calculated concentrations and extraction rates are in good agreement with experimental results. The overall volumetric mass transfer coefficient for the initial, constant rate extraction was correlated with interstitial velocity.
A freeze-coating process has been developed for the continuous production of sulfur-coated urea. This process consists essentially of immersing urea granules (initially at room temperature) in molten sulfur and removing the coated urea from the melt by centrifugal action. The entire coating operation is completed in about 1 s compared with 10 to 15 min for conventional spray-coating processes. The coating thickness and quality of coated urea produced in a laboratory-scale unit were found to be, inter alia, functions of residence time in the melt (0.6-0.8 s) and sulfur temperature (130-144 °C). Products containing 20 to 50 wt % sulfur were examined. Pinhole formation In the coats is not well understood and must be reduced to achieve high product quality.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.