Solar utility and renewability evaluation for biodiesel production process

A new design concept using solar utility to supply steam and electricity for biodiesel production was proposed. A new indicator, called the renewability index, was then defined and quantified by exergy to evaluate the benefits of substituting fossil fuel utility facilities with solar utility facilities. To reduce the unfavorable environmental impacts of the biodiesel production process, a novel process on an 8000 t a−1 scale with solar utility facilities was designed and simulated using Aspen Plus. The results show that the amount of fossil fuel consumption saved per year amounts to 1275 t of standard coal and 4676 t of CO2 release is also eliminated every year. The renewability index of the biodiesel production process with solar utility facilities is 99.9%, 10.5% higher than that with fossil fuel utility facilities. The results reported in this paper indicate that the unfavorable environmental impacts of the biodiesel production process also deserve attention and the impacts can be eliminated by using solar utility facilities.