Technical and Economical Feasibility of Production of Ethanol from Sugar Cane and Sugar Cane Bagasse

Abstract

The primary aim of this study is to investigate and analyze the sugar-ethanol plants operating in Brazil to construct a raw model to gain better understanding and insight about the technical and economical aspects of the currently operating plants. And, the secondary aim is to combine the knowledge gathered from the currently existing plant with the future design idea of converting lignocellulose into ethanol together with sucrose. The major products of the plants are ethanol and sugar. The proposed plant capacity is 5 million metric tones of sugar cane per year. The plant operation time is 174 days (4176 h) during the harvest season. The plant location is Sao Paulo state of Brazil. The designed 2005 plant produces 99.88% anhydrous ethanol and white sugar with 165,956 and 379,401 ton yearly capacities respectively. The plant is self sufficient in terms of steam and electricity requirements. The results of economical analysis of the 2005 plant reveal that the required total capital investment is $102 million. The investment is determined using the location factor of 0.4 for Brazil. The net present value of the investment is$166 million using discount rate of 4%. The same analysis reveals that the maximum interest rate that investment can remain economical through out the investment period is 26.5%. The sensitivity analysis showed that the economical values are highly sensitive to sugar cane, ethanol and sugar prices. The designed 2015 plant produces 99.89% anhydrous ethanol and white sugar with 396,872 and 370,405 ton yearly capacities respectively. For the future plant the microorganisms for fermentation are selected as recombinant Sacharomyces cerevisiae that can metabolize pentose and hexose sugars. the pretreatment method for the lignocellulose breakdown is selected as acid catalyzed steam explosion. The cellulose is hydrolyzed using cellulase enzyme. The plant is self sufficient in steam production, however, some portion of electricity demand is required to be purchased from the grid. The environmental impact of the plant is minimized by proposed waste treatment methods. The investment requirement for 2015 plant is obtained as $133 million after including the location factor of 0.4 for Brazil. The net present value of 2015 plant is obtained as$370 million for discount rate of 4%. The pay put period for the 2015 plant is obtained as 1.4 years. The discounted cash flow analysis reveals that the plant investment can stand interest rates up to 38%. As in 2005 plant the cost of sugar cane and selling price of ethanol and sugar are the major disturbances for the economic parameters.Applied Science