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Working Paper

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A Cu-ZnO-Al2O3 catalyst has been observed in laboratory scale tests to effectively produce propylene glycol from glycerol using a liquid phase hydrogenolysis reaction, which occurs at 410 F and 580 psia. A trickle-bed reactor will be used to ensure the full contact of liquid and vapor phases with the solid catalyst. This project aims to successfully scale up this reactor model, which has thus far only been tested in bench scale. The design specification stipulates that this process will produce 100 MM lb/year of propylene glycol. Using crude glycerol harvested from biodiesel production, a final product purity of 99.6% was achieved from a feedstock of 80% glycerol, 15% water, 1% methanol, and 4% sodium chloride by weight, plus trace amounts of organic salts.

The economic analysis that follows assumes a grassroots plant on the US Gulf Coast. The total capital investment was calculated to be $34.0 million, which includes a working capital of $9.78 million. Under the assumptions that the prices of crude glycerol, hydrogen, and propylene glycol are $0.22, $0.50, and $1.00 per pound respectively, the net present value (NPV) at the end of the 15 year allotted course of the project is $88.4 million and the investors’ rate of return (IRR) is 58.45%. The price of glycerol is projected to remain stable or decrease in the future and the price of propylene glycol is projected to remain stable or increase suggesting that this project could become even more profitable in the future.

The apparent profitability of this project is largely caused by the efficient and cost effective method of desalting glycerol through electrodeionization. Unfortunately, the proprietary nature of this new process precludes public access to true costing and specifications for the equipment since firms as Dow largely control the technology. Thus, conservative estimations were made in our economic analysis to account for this uncertainty.



Date Posted: 24 July 2012