| Biodiesel is a recommended petroleum-based diesel substitute mainly because it is environmentally friendly and is a renewable, domestic resource. However, compared to petroleum-based diesel, biodiesel has a higher cost, which is the major obstacle to its commercialization.; In this thesis, four different continuous alkali- and acid-catalyzed processes to produce biodiesel from virgin vegetable oil and waste cooking oil were designed and simulated. Process flowsheets, along with detailed operating conditions and equipment designs for each process were created. Technical assessment of these processes showed that the alkali-catalyzed process using virgin oil required the least amount of process equipment and no significant requirement for special materials of construction but had the highest raw material cost. The acid-catalyzed process using waste cooking oil proved to be technically feasible with a significantly lower raw material cost but required forty percent of the process equipment to be constructed from stainless steel.; An economic assessment was also performed based on the results of process simulations. The alkali-catalyzed process using virgin vegetable oil was found to have the lowest fixed capital cost. However, in terms of total manufacturing cost, aftertax rate of return and break-even price of biodiesel, the acid-catalyzed process using waste cooking oil had the lowest operating cost, the best aftertax rate of return (i.e., 10%) and the lowest break-even price (i.e., {dollar}590/tonne). In summary, the acid-catalyzed process to produce biodiesel from waste cooking oil is technically feasible and economically attractive. Results from the sensitivity analyses of the various processes indicated that plant capacity, the price of feedstock oil and biodiesel price were the factors that most significantly affected the economic feasibility of biodiesel production. |
