Drying Characteristics and Kinetics of Bitter leave (Vernonia amygdalina) and Scent leave (Ocimum gratissimum)

The effect of temperature on drying of bitter leave and scent leave was studied, using laboratory moisture content analyzer, at temperatures of 50oC, 60oC, 70oC and 80oC. The falling rate phenomenon was observed for both bitter leave and scent leave. The thin layer drying models were fitted to the experimental moisture ratio data. Among the mathematical models investigated, the Page model described better the drying behavior of bitter leaves and scent leaves with highest R2 and lower x2 values. The determined effective moisture diffusivity (Deff) values showed the temperature dependency both materials. Effective moisture diffusivity ranged from 8.437 x 10-15 to 2.96 x 10-13 m2/s for bitter leave and 8.65 x 10-14 to 4.51 x 10-13 m2/s for scent leave with increase in temperature. Hence, the Arrhenius equation was employed to ascertain activation energy for the different samples dried. Activation energies of 53.55kJ/mol and 110kJ/mol for bitter leave and scent leave were obtained respectively. Keywords: drying, kinetics, bitter leave, scent leave, effective moisture diffusivity

Simulation Model for Biodiesel Production using Non-isothermal (CSTR) Mode: Membrane Reactor

The immisicibility of vegetable oil in methanol provides a mass transfer challenge in the early stages of trans-esterification reaction in the production of biodiesel. A mathematical model capable of predicting the performance and behaviour of a membrane reactor operated in CSTR mode has been developed. The model utilized the mass balance of a typical multiphase reactor which accounted for the mass transfer rate term to generate the performance equation. Predicted concentration of species, yield and conversion of the membrane reactor were higher compared to that of conventional CSTR as shown in Table 1. The effect of temperature on yield, and conversion was also considered. The temperature at 40o C exhibited the highest yield and conversion of methyl ester compared to 25 oC and 60 o C Keywords: biodiesel, mass transfer limitation, membrane reactor, modeling, vegetable oi