Cracking and hydrocracking of triglycerides for renewable liquid fuels: alternative processes to transesterification

Abstract

Os processos industriais mais utilizados na produção de combustíveis líquidos semelhantes ao diesel usam catalisadores homogêneos básicos através das metanólise e etanólise de óleos tais como os de soja, canola, palma entre outros. Desse modo, se obtém o biodiesel. Por sua vez, transformações termo-catalíticas usando as facilidades existentes nas refinarias de petróleo são alternativas que merecem atenção devido a sua viabilidade econômica. De fato, três processos industriais já estão em funcionamento e novos projetos estão em fase final para comercialização. O presente trabalho analisa os experimentos já realizados por pesquisadores brasileiros nas áreas do craqueamento, do craqueamento catalítico e do hidrocraqueamento catalítico dos óleos vegetais puros ou modificados. A partir dos resultados descritos, são sugeridas novas direções destas pesquisas para os próximos anos.The most used industrial processes for the production of liquid fuels like diesel type are based on the methanolysis and ethanolysis of various oil reactants, such as palm, soybean and rapeseed oils, in the presence of homogeneous base catalysts. However, thermal and catalytic transformations of vegetable oils using available reactors and industrial processes are possible alternatives and deserve attention. In fact, three industrial processes are operating and new projects are announced. The present work analyses the experimental studies performed up to now by Brazilian researchers in the field of cracking, catalytic cracking and hydrocracking of pure or modified vegetable oils. From the published results, some research areas for the near future are suggested.

Development of nickel based catalysts for the transformation of natural triglycerides and related compounds into green diesel: a critical review

“…The cracking/hydrocracking ( Fig. 2) performed over acidic catalysts results to the so-called organic liquid product, namely a mixture of hydrocarbons (in the gasoline, kerosene and diesel range) with traces of shorter chain oxygenates as well as hydrocarbon gases (C 3 -C 5 ) and coke [74 and references there in, [84][85][86][87][88][89][90][91]. The hydrocarbons obtained by cracking of triglycerides consist, besides paraffins, of naphthenes and aromatics obtained by secondary reactions.…”

“…The production of the organic liquid product can be obtained also by hydrocracking. The presence of hydrogen somewhat protects the active phase of the catalysts used (supported metal or sulfide) [74 and references there in, 90,91].…”

Metabolic strategies for microbial glycerol overproduction

“…Microbial glycerol production was attempted during the early 1940s based on Neuberg's investigation on alcoholic fermentation, but failed to gain importance industrially when compared with the synthetic chemical routes due to low yields of glycerol and difficulties encountered in purification and extraction of the target from fermentation broth , . Due to a new trend in the bioenergy industry where fats and oils are cracked down directly to hydrocarbons, it is probable that glycerol will not be produced in the biodiesel industries in future . Yet, due to its multifaceted applications, the demand for glycerol remains.…”

Production of Renewable Hydrocarbons from Thermal Conversion of Abietic Acid and Tall Oil Fatty Acids

“…1,2 Three main processes for conversion of fatty acids or oils/fats to biofuels and linear hydrocarbons are pyrolysis or thermal cracking, 3 transesterification, 4 and hydroprocessing. 5 The transesterification process focuses on an esterification reaction between an alcohol, usually methanol, and triglycerides or fatty acids. This process has several drawbacks, including substantial methanol usage, which itself is a product from fossil-based sources, and glycerol production as a byproduct of the reaction, which is difficult to remove from the desired products and derived process salts.…”