Document Type

Working Paper

Date of this Version

4-2014

Abstract

This project aims to produce n-butanol from ethanol using a catalyst and pressurized hydrogen. Our process converts 100MM gallons of ethanol to 71.4 MM gallons of 95% pure butanol per year. The fixed-bed catalytic reactor contains spherical pellets of Ru(acac)3 with a void fraction of 0.391, and operates at 374 °F and 725 psi. Following the reaction, the hydrogen is removed from the product stream using two flash separation units before being recycled to the reactor. The butanol product is then taken from the bottoms of a distillation tower. The remaining ethanol and water are separated using two distillation units and ethylene glycol as an entrainer. The plant will be located in Iowa, U.S.A. where an adjoining ethanol plant uses corn as a feedstock for its process.

Since this project assumes a future market for butanol biofuel, and our process uses ethanol as a feedstock, the price of butanol is assumed to be some multiple of the ethanol price. At the current ethanol price, assuming that butanol is 1.5 times the price of ethanol, our process is not profitable. It was found that in order to have a positive Net Present Value after 15 years, the price of butanol would need to be 2.225 times the price of ethanol, which would currently be $6.54 per gallon of butanol. Therefore, while profitability is not achievable in the current market, this process should be seriously considered in the future due to the high volatility of biofuel prices and policies.

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Date Posted: 25 July 2014