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A plant utilizing a two-step reaction process, which takes a 95% ethanol stream (by mass) and produces a 98% 1,3-butadiene stream, was designed for this project. The production goal for this plant was 200,000 tonnes of butadiene with the main motivation behind the project being the recent rise in butadiene prices. The process first passes ethanol through a catalytic dehydrogenation reactor to convert ethanol to acetaldehyde and hydrogen. A kinetic model was used to determine the reaction rates and operating conditions of the reactor. The acetaldehyde intermediate is further reacted with ethanol in a catalytic reactor to form butadiene. A hydrogen byproduct stream is also generated in this design and is purified for sale.
This report provides a design and economic analysis for the production of butadiene on the Gulf Coast. Process flow sheets, energy and utility requirements, and equipment summaries are provided and analyzed. Process profitability is sensitive to the cost of both ethanol and butadiene. It is shown that the plant is very profitable for its expected 15-year lifespan with an expected internal rate of return of 40%, return on investment of 34%, and net present value of $172,000,000 (for a discount rate of 15%). The process becomes unprofitable if the price of ethanol increases to over $3.00/gallon. A combination of increased ethanol price and decreased butadiene price will also cause the plant to be unprofitable. Therefore, plant construction is only recommended given an acceptable price of ethanol and butadiene.
Date Posted: 20 August 2012