Optimised small scale reactor technology, a new approach for the Australian biodiesel industry
de Boer, Karne (2010) Optimised small scale reactor technology, a new approach for the Australian biodiesel industry. PhD thesis, Murdoch University.
With growing concern over peak oil and global warming many are urgently seeking alternatives to petro-diesel to fuel growing economies. Biodiesel, a diesel equivalent derived from vegetable oils and animal fat, is one such alternative. Large scale uptake of biodiesel, however, is limited by the availability of low cost, sustainable feedstocks.
In the context of feedstock limitations in Australia, this thesis examines the complete biodiesel system from feedstock to end consumer via production technology. The result of this investigation was the identification of integrated small scale biodiesel production (less than 5 million L/yr) as an economically viable niche for the Australian biodiesel industry. This is especially the case in remote locations.
To this end, a new production model, based upon small scale operations in regional industry hubs, was presented and validated with a case study in South Western Australia. This production model presents a new approach for the Australian biodiesel industry.
Having established the economic sustainability of the small scale production model, this work lays a foundation for its technical viability by optimising the reactor technology at the heart of biodiesel production. The following two questions are examined in the pursuit of reactor technology optimisation for small scale production:
•What is the most suitable catalyst for small scale production?
•Can an accurate model of the reactor be developed to facilitate optimisation?
The first question necessitated a detailed review of biodiesel production technology. The fruit of this review was the identification of homogeneous catalysed technology as the most suitable method for small scale biodiesel production. The second question required a reactor model that could determine the level of conversion on the basis of reactor temperature and residence time (flow-rate).
Further investigation into the homogeneous catalysed reaction medium suggested a two part model, with the first focusing on flow characteristics to maintain dispersion of the reacting phases, and the second on kinetics to determine conversion. Due to the multiphase nature of the reaction medium, the first part was developed as a Computational Fluid Dynamic (CFD) model of the flow through Bluediesel PTY LTD’s tubular reactor in ANSYS CFX. This model drew heavily on literature in the field of oil and water flows and was verified with flow visualization studies of the reactor. The second part of the model was built in MATLAB on the basis of biodiesel kinetic studies and was verified with data from Bluediesel PTY LTD’s plant.
This model was ran at a number of operating conditions and configurations to determine the minimum total cost of a small scale reactor while maintaining suitable levels of conversion. This optimisation work represents the first application of CFD modelling to a biodiesel reactor and can be used as a basis for further work in this area.
|Publication Type:||Thesis (PhD)|
|Murdoch Affiliation:||School of Engineering and Energy|
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