Conversion of Cow Manure Pyrolytic Tar Under FCC Conditions Over Modified Equilibrium Catalysts

Abstract

Changes were produced by means of alkaline lixiviation in the porosity of an equilibrium commercial FCC catalyst formulated to maximize the yield of middle distillates, in order to improve its performance in the conversion of tar from the pyrolysis of cow manure into hydrocarbons. The pyrolysis was produced at 650 °C in a fixed bed reactor and the tar was catalytically upgraded, comparing the performances of the parent and modified catalysts under realistic FCC conditions, in a CREC Riser Simulator reactor at 550 °C during 10 s, catalyst to reactant relationships being 3, 5 and 8. The alkaline treatment increased both acidity and average mesopore size of the commercial catalyst, thus favoring the diffusion process of the bulkiest oxygenated molecules in tar. The modified catalyst was more effective in deoxygenating tar (conversions up to 87.5% and deoxygenation up to 74.6%), producing more hydrocarbons and coke than the parent catalyst. According to the chemical nature of the pyrolitic tar from cow manure, a high proportion of paraffins derived from the primary cracking of its components were observed among the product hydrocarbons in the gasoline range over both catalysts.