Study On Biodiesel Fuel Production In A Magnetically Stabilized Fluidized Bed Reactor By Whole-cell Bio-catalyst

Because of the good combustion properties and environment-friendly features, biodiesel has drawn an increasing attention among the world. However, the preparation of biodiesel by whole-cell catalyst remains in laboratory scale. There still have a lot of work to do in the reactor research and process design. Therefore, the technology of biodiesel fuel continuous production in a magnetically stabilized fluidized bed reactor system by whole-cell bio-catalyst was explored in this dissertation.Chemical co-precipitation was chosen to synthesize the nano-Fe3O4 magnetic particles. When n(Fe2+)/n(Fe3+)=1/1.8, alkaline precipitant was ammonia water, adding speed was 15 mL/min, temperature was 60℃and pH was 10, the obtained magnetic particle had good magnetism performance (72.1 emu/g) and small diameter (11.5 nm).Magnetic chitosan microspheres were prepared via suspension cross-linking technique in the application of the formaldehyde. When the mass ratio of Fe3O4/chitosan was 1:0.8, formaldehyde in initial cross-linking process was 0.5 %, Span 80 was 10 g/L and the stirring rate was 1500 r/min, the obtained magnetic chitosan microspheres had good cell binding capacity and can be used as carriers to immobilize cell. Based on this particle, a new whole-cell bio-catalyst was prepared by immobilizing R. oryzae cells with swelling-adsorption. And the factors of transesterification reaction using this catalyst were studied.A multi-phase magnetically stabilized fluidized bed reactor was designed. The relationship between current intensity and magnetic field strength of this reactor was H=9239I. The fluid characteristics of the Fe3O4/CS composite microspheres, BSPs and Chitosan-MCB were compared by a series of cold-tests. The former played better flow characteristics and operational stability. The best fluid state was on the condition of the magnetically stabilized operation. An innovative continuous process of biodiesel production by combining superparamagnetic whole-cell bio-catalyst and four continuous magnetically fluidized bed reactor system was proposed. The optimized factors of this process were using magnetic steady-state operation, methanol to oil molar ratio of 0.75:1, quantity of catalyst with 12 % of oil and the feed rate of 42.6 mL/min. The final methyl ester production rate was over 85 %, even after 200 h continuous operation, production rate of the forth exports was more than 80 %.