Shouyun Cheng

Hydrodeoxygenation of prairie cordgrass bio-oil over Ni based activated carbon synergistic catalysts combined with different metals

Bio-oil can be upgraded through hydrodeoxygenation (HDO). Low-cost and effective catalysts are crucial for the HDO process. In this study, four inexpensive combinations of Ni based activated carbon synergistic catalysts including Ni/AC, Ni-Fe/AC, Ni-Mo/AC and Ni-Cu/AC were evaluated for HDO of prairie cordgrass (PCG) bio-oil. The tests were carried out in the autoclave under mild operating conditions with 500psig of H2 pressure and 350°C temperature. The catalysts were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and transmission electron microscope (TEM). The results show that all synergistic catalysts had significant improvements on the physicochemical properties (water content, pH, oxygen content, higher heating value and chemical compositions) of the upgraded PCG bio-oil. The higher heating value of the upgraded bio-oil (ranging from 29.65MJ/kg to 31.61MJ/kg) improved significantly in comparison with the raw bio-oil (11.33MJ/kg), while the oxygen content reduced to only 21.70-25.88% from 68.81% of the raw bio-oil. Compared to raw bio-oil (8.78% hydrocarbons and no alkyl-phenols), the Ni/AC catalysts produced the highest content of gasoline range hydrocarbons (C6-C12) at 32.63% in the upgraded bio-oil, while Ni-Mo/AC generated the upgraded bio-oil with the highest content of gasoline blending alkyl-phenols at 38.41%.

Development of hydrocarbon biofuel from sunflower seed and sunflower meat oils over ZSM-5

Individually, sunflower oil produced from inedible sunflower seeds with hulls and sunflower meats without hulls were catalytically cracked over the ZSM-5 catalyst in a fixed-bed reactor at three reaction temperatures (450 °C, 500 °C, and 550 °C). Characterizations of hydrocarbon biofuel, distillation residual, and non-condensable gas were carried out. The reaction temperature on the hydrocarbon biofuel yield and quality from sunflower seed oil and sunflower meat oil were discussed and compared. In addition, a preliminary cost analysis of the sunflower seed dehulling was carried out. The results showed that the highest hydrocarbon biofuel yield was obtained from upgrading sunflower meat oil at 500 °C. The highest meat hydrocarbon biofuel yield was 8.5% higher than the highest seed hydrocarbon biofuel yield. The reaction temperature had a significant effect on the distribution of non-condensable gas components. Furthermore, the reaction temperature affected the yield and properties of hydrocarbon biofuel. The unit cost of producing sunflower meat oil was lower than that of producing sunflower seed oil. Comprehensively, sunflower meat could be a more economical feedstock than sunflower seed to produce hydrocarbon biofuel.

A roadmap towards green packaging: the current status and future outlook for polyesters in the packaging industry

Approximately 99% of the plastics produced today are petroleum-based, and the packaging industry alone consumes over 38% of these plastics. In this review, we argue that renewable polyesters can provide a key milestone as renewable plastics in the route toward green packaging. This review describes different classes of polyesters with particular regard to their potential use as packaging materials. Some of the families of polyesters discussed include poly(ethylene terephthalate) and its renewable analogs, poly(lactic acid), poly(hydroxyalkanoates), and poly(epoxy anhydrides). The synthesis of polyesters is discussed from a green chemistry perspective. A structure–property correlation among the various polyesters is also discussed. The challenges that currently hinder the widespread adoption of polyesters as leading packaging materials are reviewed. The environmental footprint and end of life scenario of polyesters are discussed. Finally, future research directions are summarized as a possible roadmap towards the widespread adoption of renewable polyesters as sustainable packaging materials.

Development of a bifunctional Ni/HZSM-5 catalyst for converting prairie cordgrass to hydrocarbon biofuel

ABSTRACT Ni/HZSM-5 catalysts were prepared using the impregnation method. The HZSM-5 and impregnated Ni/HZSM-5 catalysts were characterized by Brunauer–Emmett–Teller and X-ray diffraction. The HZSM-5 and Ni/HZSM-5 catalysts were used for prairie cordgrass (PCG) thermal conversion in a two-stage catalytic pyrolysis system. The products contained gas, bio-oil, and bio-char. The gas and bio-oil were analyzed by gas chromatography and gas chromatography–mass spectrometry separately. Higher heating values and elemental composition of bio-char were determined. The results indicated that 12% Ni/HZSM-5 treatment yielded the highest amount of gasoline fraction for hydrocarbons and showed a robust ability to upgrade bio-oil vapor.

Synthesis of High Molecular Weight Polyester Using in Situ Drying Method and Assessment of Water Vapor and Oxygen Barrier Properties

The preparation of renewable polyesters with good barrier properties is highly desirable for the packaging industry. Herein we report the synthesis of high molecular weight polyesters via an innovative use of an in situ drying agent approach and the barrier properties of the films formed from these polyesters. High number average molecular weight (Mn) semiaromatic polyesters (PEs) were synthesized via alternating ring-opening copolymerization (ROCOP) of phthalic anhydride (PA) and cyclohexene oxide (CHO) using a salen chromium(III) complex in the presence of 4-(dimethylamino)pyridine (DMAP) cocatalyst. The use of a calcium hydride (drying agent) was found to enhance the number Mn of the synthesized PEs, which reached up to 31.2 ku. To test the barrier properties, PE films were prepared by solvent casting approach and their barrier properties were tested in comparison poly(lactic acid) films. The PE films showed significantly improved water vapor and oxygen barrier properties compared to the commercial poly(lactic acid) (PLA) film that suggests the potential use of these PEs in in the food packaging industry.

Effect of Co-Mo/HZSM-5 on ex-situ catalytic fast pyrolysis of different biomass feedstocks

Abstract. Biomass can be converted to hydrocarbon biofuel through the integration of pyrolysis and catalytic cracking. In this study, the effects of Co-Mo/HZSM-5 on catalytic fast pyrolysis of different biomass feedstocks were investigated using a two-stage reactor. Two grassy biomass (switchgrass and prairie cordgrass), and one woody biomass (pine sawdust) were chosen as feedstock. The results indicated that Co-Mo/HZSM-5 reduced bio-oil yield in comparison with non-catalytic pyrolysis, but it produced upgraded bio-oil with higher contents of hydrocarbons and phenols. Pine sawdust produced highest bio-oil yields compared to prairie cordgrass and switch grass. Prairie cordgrass generated the upgraded bio-oil with the highest hydrocarbon content at 36.07%, while switch grass produced the upgraded bio-oil with the lowest hydrocarbon content at 14.08%. Bio-char obtained from pine sawdust pyrolysis had highest HHV value (28.56MJ/kg), which can be used as an excellent solid fuel.