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Science AMA Series: I’m Dr Neil Stacey, a biofuels researcher at the University of the Witwatersrand. I’ve shown that the cost of distilling ethanol for fuel use can be reduced by just blending gasoline directly into the ethanol/water mixture. AMA!
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Purifying ethanol is energy-intensive and expensive. When we’re just using it in a fuel blend, it’s also unnecessary. The real end-product of ethanol production for fuel use isn’t pure ethanol itself but rather a fuel blend which contains ethanol; pure ethanol need not be an intermediate step. Reconsidering the overall flow-sheet in this way opens up a far broader optimization space in which to find energy-efficient separation processes and in a recent Energy and Fuels paper, my colleagues and I demonstrated a more energy-efficient separation process making use of a natural liquid phase split to eliminate water without the addition of further energy for separation. Our process cuts the energy consumption of ethanol production by up to 2MJ per liter and has a lower capital cost than conventional azeotropic distillation. It is, however, just one of many new processes that become possible once you discard the assumption that a pure biofuel is the ultimate end-product. I am here with Shell engineer Ari Hadjitheodorou to talk about the challenges of implementing this concept in the field. Ask us anything! Questions about the violent #FeesMustFall protests on our campus are not off-limits, though we prefer to stick to the science. We will be back at 11 am ET (8 am PT) to answer your questions, ask us anything! Edit: Link to paper. Sadly our currency in South Africa has recently stopped being worth anything, so the university wouldn’t fork out the fee for Open Access, so here’s a link to a news article that summarizes it. Edit2: It’s 7PM over here, so I need to do some real-world stuff (dinner, human contact etc) so I’ll be wrapping up for now. I’ll stop by again in the morning to answer anything else that’s come up. Thanks everyone for the questions and the support and a big thank you to the mods!