Modelling of Microtube Reactor In Bio-Fuel Production Using CFD

Nowadays, the biological resources are the best option as alternative to the petroleum-based fuels or petrochemical solvents for renewable energy and green chemistry applications. Over the last 15 years, the production of biodiesel fuels (BDF) mainly composed of fatty acid methyl esters (FAME), had been intensively studied as it is an organic, biodegradable and non-toxic fuels source that is made from renewable resources including animal fats and vegetable oils. In spite of the usage of virgin and food grade oils have proven to be suitable feedstock for biodiesel production, the concern on the proper usage of widespread farmland areas for the production in the detriment of food supply have play an important role on the final chosen feedstock. The usage of non-edible crops like jatropha or castor oil, do not resolve the problem of requiring large plantation area. BDF is defined as the monoalkyl esters of long-chain fatty acids synthesized by transesterification of triglyceride in vegetable oils or animal fats with alcohol to form fatty acid methyl ester (FAME). This project has theoretically assessed the transesterification of sunflower oil with methanol to produce fatty acid methyl esters (FAME) using KOH catalyst in a microchannel tube reactor using AN SYS Fluent. Micro-reactor is considered for better heat and mass transfer, also micro-reactor provides admissible control over unwanted side reactions. The exact reaction path of biodiesel production is unknown so the lumped kinetics model is being used instead. Computationally, the volume fraction, the velocity profile, the pressure drop, density profile, and temperature profile are
being examined based on the experimental setup which is using the methanol/oil molar ratio = 23.9 at 40 °C. The dimension of microreactor is fixed to 0.8 mm diameter. Based on the experimental result, the flow pattern at the entrance region of the microtube was segmented flow of the methanol and oil phases. As the reaction progress, fine droplets composed of the produced glycerol and methanolwere dispersed and circulated in the oil segments. At a methanol/oil molar ratio of 23.9 at 60 °C, a quasi-homogeneous phase form approximately 300mm from the reaction inlet where the oil completely converted to FAME.