Brazil's Dedini SA, a leading manufacturer of sugar and biofuel equipment, has announced that it has demonstrated a cellulosic ethanol process on an industrial scale, a development that could revolutionize the industry by boosting the competitiveness and energy balance of biofuels.
Dedini's São Luiz Mill in São Paulo state began producing cellulose ethanol from bagasse - the leftover cane stalk after the sucrose is pressed out - at about US$ 40 cents a liter in 2002. Production costs have now fallen, due to improvements in processing technologies, to below €20/US$ 27 cents a liter (US$ 1.02 per gallon).
"This means the fuel is cost-competitive with oil at US$42 a barrel," said Dedini Operations Vice President José Luiz Olivério at the seminar.
Further commenting, Oliverio said "this will be able to boost a mill's ethanol output by 30 percent without planting one more cane stalk". In short, a hectare of sugar cane will deliver a third more ethanol and now yield up to 9000 liters, three to four times more than corn.
The technology uses two pretreatment steps to convert bagasse, the lignocellulose-rich byproduct from cane processing, into ethanol: (1) pretreatment of the biomass with organic solvents, and (2) dilute acid hydrolysis. The innovation consists of adding a first stage pretreatment step which allows the diluted acids to do their work much faster and more efficiently.The liquid hydrolyzates are then easily fermented and distilled into ethanol. Because of the speed of the process, the proprietary technique has been dubbed 'Dedini Rapid Hydrolysis' (DHR).
By pretreating the biomass with organic solvents, the lignocellulose is decomposed, which allows for a much faster attack of the acids. The hydrolyzed fraction that is then to be turned into ethanol is easily fermentable because it consists of hexoses - a monosaccharide consisting of 6 carbon atoms.
Dedini's first large scale demonstration facility produced 5000 liters per day. The objective is now to optimize the technique by means of process integration, automation and by increasing the stability and safety of the sensitive conversion process. Olivério thinks it must be possible to go beyond the current 30% increase in sugar cane ethanol production per hectare, and achieve a doubling within a few years.
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