(654d) Identification Of The Cracking Mechanism Of Mono-, Di-, And Triglycerides Over H-Zsm-5 Catalyst

Renewable fuels will be essential to sustain future energy demand, as petroleum supply decreases and economies of developing nations continue to grow at a fast pace. Biodiesel, a mixture of fatty acid methyl esters, produced from refined vegetable oils and animal fats, has been successfully produced and distributed for the last 10 years. Production has grown exponentially since the late 1990's. A by-product of biodiesel production is glycerine. Currently, glycerine has little or no market value and has become problematic to biodiesel producers. An alternative to overcome production of unwanted by-products and expand the inventory of oils available for producing fuels is the application of a more robust conversion process. Green diesel could be produced via cracking of crude lipids using catalytic processes currently employed in the petroleum refining industry. In contrast to biodiesel, green diesel could be distributed via diesel pipelines. And its production does not generate glycerine as a by-product.

In this work, mono-, di-, and triglycerides of oleic acid were cracked over H-ZSM-5 solid catalyst at 400°C in a micro-bed reactor coupled with online GC/MS analysis. H-ZSM-5 was selected due to its high Bronsted acidity and its shape selective characteristics. The operating conditions during the experiments minimized the formation of secondary cracking products. A cracking model was postulated based upon the initial contact of the reactant with the catalyst. Initial cracking products were diesel-range and gasoline-range organics. The reaction products indicate deoxygenation and cracking of the acylglycerols to form aliphatic and cyclic compounds.