Producing petrochemicals from catalytic fast pyrolysis of corn fermentation residual by-products generated from citric acid production

Citric acid production from corn fermentation generates significant amounts of fermentation residual by-products that need to be disposed of. To valorize the corn fermentation residues (CFRs), this study investigated catalytic fast pyrolysis (CFP) of CFRs alone or with low-density polyethylene (LDPE) to produce petrochemicals (aromatic hydrocarbons and olefins) using ZSM-5 zeolites as the catalyst. Results indicate that ZSM-5 zeolites decreased the activation energy of CFRs thermal decomposition by ∼15%. In addition, the introduction of ZSM-5 dramatically changed the compositions of condensable products from predominantly oxygenated compounds (e.g., furans, ketones, and acids) in non-CFP of CFRs to essentially aromatic hydrocarbons (e.g., benzene, toluene, and xylenes (BTX)) in CFP. Petrochemical yield of 30.4 C% was obtained in CFP of CFRs alone, and further improved to 40.3–52.1 C% when 10–33.3 wt.% LDPE was co-fed with CFRs in CFP. Important primary petrochemicals (BTX, ethylene and propylene) constituted the predominant fractions (66.8–71.1%) of the petrochemical products from CFP of CFRs alone and co-feed CFP with LDPE. These results indicate that CFRs are an attractive biomass feedstock for the production of high value-added petrochemicals by CFP process.