Date of this Version
This report details a process designed to renewably produce 400 million pounds of para-xylene per year from corn dry grind, sugar cane molasses (SCM), or woody biomass while minimizing water use. The para-xylene should be suitable for the production of polymers and plastics, and should be economical and green. All three feedstocks are equally suitable for the process and available for use.
The process is designed for SCM and consumes a total feed of 9.35 billion pounds of molasses per year. Corn dry grind is simply too expensive, and biomass, while cheaper per pound, imposes too many additional pre-processing costs. The molasses first undergoes hydrolysis then hydrogenation, followed by condensation and separation involving distillation and crystallization. Transalkylation and aqueous phase reforming are also employed to boost yield and create a self-contained process.
Several key assumptions are inherent in this process’s design. First, all reactor yields come directly from specific examples in the literature. Second, results found in the patents for glycerol were assumed valid for sorbitol as well, since not all patents used the same materials for their examples. Third, the economic analysis assumes that raw materials for catalyst manufacture can be purchased in bulk for a quarter of the price for small quantities. This assumption was suggested by Dr. Fabiano.
Based on these assumptions, the process designed herein meets the desired non-financial criteria, but results in an investor’s rate of return of negative 2.90% and a net present value of negative $196 million. However, further research into the catalyst or reactor yields could easily allow the process to break even or offer an attractive return.
Date Posted: 20 August 2012