Upgrading of Coffee Biocrude Oil Produced by Pyrolysis of Spent Coffee Grounds: Behavior of Fatty Acids in Supercritical Ethanol Reaction and Catalytic Cracking

Spent coffee grounds contain lipids (fatty acids) in addition to cellulose, hemicellulose, and lignin. The reaction process for upgrading biocrude oil produced from spent coffee grounds is different from that followed for upgrading biomass pyrolysis oil, such as processes that utilize sawdust. The feasibility of upgrading coffee biocrude oil through a supercritical ethanol reaction with plastic pyrolysis oil and through catalytic cracking for the improvement of the undesirable properties of biocrude oil, caused by the presence of oxygenated compounds, was evaluated. The initial oxygen content of the coffee biocrude oil was 16.9 wt%. The oil comprised a total content of 40.9% fatty acids, as found by analyzing the GC-MS peak area. After the supercritical ethanol reaction at 340 ∘C, the oxygen content was decreased to 9.9 wt%. When the MgNiMo/AC catalyst was applied to the supercritical reaction, the oxygen content was further decreased to 8.5 wt%. The esterification of the fatty acids in the biocrude oil with ethanol converted them to esters. After the supercritical reaction of coffee biocrude oil with plastic pyrolysis oil (1:2 (w/w)), the oxygen content was 6.4 wt%. After the catalytic cracking of the biocrude oil by Ni/MCM-41 at 400 ∘C, the fatty acids were converted to hydrocarbons, C9 to C21, and the oxygen content decreased to a final value of 2.8 wt%.

Effect of a Gradient Term on the Solvability of the Heat Equation with a Supercritical Reaction with Respect to the Hardy Potential

In this paper we consider the following nonlinear parabolic problemwhere Ω ⊂ ℝ

The Degradation of Decabromodiphenyl Ether in the Supercritical Fluid

Currently, environmental contamination by polybrominated diphenyl ethers (PBDEs) in the world is of important concern and requires the effective remediation technologies. The degradation of decabromodiphenyl ether (BDE-209) in the supercritical n-hexane by zerovalent iron was studied in this work. The results showed that BDE-209 can be rapidly reduced into nona-, octa-, hepta-and lower brominated polybrominated diphenyl ethers (PBDEs) under the supercritical reaction conditions. Among n-hexane, methanol, tetrahydrofuran and mixed n-hexane+ tetrahydrofuran solvents, the conversion of BDE-209 in tetrahydrofuran was the highest. BDE-209 conversion increased with increased reaction temperature and pressure. Under the reaction condition: temperature: 523K; pressure: 3.2Mpa; reaction time: 10min; reaction system: 200ml 50mg BDE-209/L n-hexane; atmosphere: N2and catalyst load: 2g/L, the conversion of BDE-209 was as high as 88.9%.