| Rapeseed and cottonseed meal after they are squeezed for oil are potential protein resources for feed and food. Because of the toxic glucosinolates in rapeseed meal or gossypol in cottonseed meal, the rich protein in meals has not yet been utilized reasonably.Two-liquid phase solvent (TPS) extraction technique, invented by Rubin et al (University of Toronto), could obtain high-level rapeseed oil and toxin-free meal simultaneously. Our research group transplanted and improved the TPS technique in processing the Chinese rapeseed and cottonseed, obtained qualified meal.From bench test to commercial-scale application, TPS technique still has many problems to be investigated and solved. This dissertation studied the problems in dynamics and experimental simulation in the scale-up of leaching and desolventizing of toxic oil seeds (rapeseed and cottonseed) with TPS. The main issuers are as follows.1 Dynamic study in rapeseed TPS leachingThe dynamic data of rapeseed leaching by TPS in literature were rare and lack of consistence. This dissertation carried out a comprehensive investigation on rapeseed-leaching dynamics with TPS containing basic additives. The temperatures were 15-50; Ground rapeseed diameter 0.32-0.427mm; Ratio of methanol to rapeseed 4-6 ml/g; Ratio of hexane to rapeseed 2-4 ml/g; Leaching time 2-210 min. The results of the study showed that:(1) The effect of rapeseed particle size and temperature on leaching yields of oil and glucosinolates was obvious. The smaller the particle size, the quicker the leaching rate. The higher the temperature, the quicker the leaching rate, and the higher the leaching yield.(2) The effect of TPS ratio to rapeseed on leaching yield was obvious. The bigger the ratio of methanol to rapeseed, the quicker the glucosinolates-leaching rate and the higher the yield. The bigger the ratio of hexane to rapeseed, the quicker theoil-leaching rate and the higher the yield.(3) Foundation of TPS leaching model and its application. Mass transfer mechanism in leaching rapeseed by TPS had been analyzed and a liquid-liquid-solid leaching model was found. The quantitative expressions between model parameters and leaching conditions were determined by non-linear regression analysis. The dynamic data of leaching rate calculated by the model was identical with the 324 values determined by experiments. The dependence of diffusion coefficients both of oil and glucosinolates within rapeseed meal on temperature calculated by the model showed a good consistence with Arrhenius equation.2 Simulation of multistage cocurrent leaching of rapeseed with TPSThe glucosinolates content in Chinese rapeseed was in many times the Canadian's rapeseed (conola) and a multistage methanol washing was needed after oil recovery. In order to simplify the process and decrease the solvent loss, a simplified process was proposed in the dissertation by uniting two-step processing, separately for the leaching of oil and gluconolates, into one, the multistage cocurrent leaching with TPS. To verify the feasibility of the idea, a cascade experiment were carried out.(1) Analysis of leaching factors and optimal leaching conditions. It was feasible to leach oil and remove glucosinolate simultaneously from Chinese rapeseed within a leaching apparatus. The number of stage was one of the main factors. The more the stages, the better the leaching result. In general, 4 theoretical stages would lead to a meal with residual oil below 1% and glucosinalates below 30 mol/g. In 40-50, the proper ratio of hexane to rapeseed was 2 ml/g. The proper ratio of methanol to rapeseed was 3.3 ml/g and water content in methanol phase was 10v%.(2) Foundation of theoretical stage model for liquid-liquid-solid three-phase cocurrent oil leacher. A model for calculation of theoretical stages in liquid-liquid-solid three phase leaching was proposed. The model correlated the relative flow rate of each stream entering and leaving the leacher and the equilibrium solubility of oil in each stream. The model also included the ba...
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