Moriko Qian

Optimizing carbon efficiency of jet fuel range alkanes from cellulose co-fed with polyethylene via catalytically combined processes

Enhanced carbon yields of renewable alkanes for jet fuels were obtained through the catalytic microwave-induced co-pyrolysis and hydrogenation process. The well-promoted ZSM-5 catalyst had high selectivity toward C8-C16 aromatic hydrocarbons. The raw organics with improved carbon yield (∼44%) were more principally lumped in the jet fuel range at the catalytic temperature of 375°C with the LDPE to cellulose (representing waste plastics to lignocellulose) mass ratio of 0.75. It was also observed that the four species of raw organics from the catalytic microwave co-pyrolysis were almost completely converted into saturated hydrocarbons; the hydrogenation process was conducted in the n-heptane medium by using home-made Raney Ni catalyst under a low-severity condition. The overall carbon yield (with regards to co-reactants of cellulose and LDPE) of hydrogenated organics that mostly match jet fuels was sustainably enhanced to above 39%. Meanwhile, ∼90% selectivity toward jet fuel range alkanes was attained.

Development of a catalytically green route from diverse lignocellulosic biomasses to high-density cycloalkanes for jet fuels

This study reports a novel route to manufacture high-density cycloalkanes for jet fuels from diverse lignocellulosic biomasses. The consecutive processes for manufacturing high-density cycloalkanes primarily included the catalytic microwave-induced pyrolysis of diverse lignocellulosic biomasses (hybrid poplar, loblolly pine and Douglas fir) over a well-promoted ZSM-5 and a hydrogenation process in the presence of a RANEY® nickel catalyst. Two variables (catalytic temperature and catalyst-to-biomass ratio) were employed to determine the optimal conditions for the production of C8–C16 aromatics in the catalytic microwave-induced pyrolysis. The maximum carbon yield of the desired aromatics was 24.76%, which was achieved from the catalytic microwave-induced pyrolysis of hybrid poplar at 500 °C with the catalyst-to-biomass ratio of 0.25. We observed that the aromatics derived from catalytic microwave-induced pyrolysis in the n-heptane medium were completely hydrogenated into renewable high-density cycloalkanes for jet fuels. In the hydrogenation process, increasing the catalyst loading and reaction temperature could promote the selectivity to high-density cycloalkanes. The results indicated that hybrid poplar was the optimal feedstock for obtaining the highest selectivity (95.20%) towards high-density cycloalkanes. The maximum carbon yield of cycloalkane-enriched hyrogenated organics based on hybrid poplar was 22.11%. These high-density cycloalkanes with high selectivity can be directly used as additives in jet fuels, such as JP-5, JP-10 and RJ-5.

A thermal behavior and kinetics study of the catalytic pyrolysis of lignin

The aim of the present study is to convert lignin into bio-based phenols by catalytic pyrolysis using activated carbon (AC) as a catalyst. The thermal decomposition behavior of lignin pyrolysis was investigated using a thermogravimetric analyzer (TGA). The heating rate played a significant role in lignin thermal degradation, the mass loss of lignin in pyrolysis increased with the increase of heating rate. The reaction kinetics of lignin pyrolysis was determined and compared using microwave and conventional heating, a second-order reaction mechanism fitted well for lignin pyrolysis, and the results revealed that the activation energy for catalytic microwave pyrolysis of lignin was 7.32 kJ mol−1, which was remarkably lower than that for conventional pyrolysis of lignin (59.75 kJ mol−1). The reaction mechanism of this process was analyzed.