Xianhui Zhao

Catalytic cracking of non-edible sunflower oil over ZSM-5 for hydrocarbon bio-jet fuel

Non-edible sunflower oils that were extracted from sunflower residual wastes were catalytically cracked over a ZSM-5 catalyst in a fixed-bed reactor at three different reaction temperatures: 450°C, 500°C and 550°C. The catalyst was characterized using XRD, FT-IR, BET and SEM. Characterizations of the upgraded sunflower oils, hydrocarbon fuels, distillation residues and non-condensable gases were carried out. The effect of the reaction temperature on the yield and quality of liquid products was discussed. The results showed that the reaction temperature affected the hydrocarbon fuel yield but had a minor influence on its properties. The highest conversion efficiency from sunflower oils to hydrocarbon fuels was 30.1%, which was obtained at 550°C. The reaction temperature affected the component content of the non-condensable gases. The non-condensable gases generated at 550°C contained the highest content of light hydrocarbons (C1-C5), CO, CO2 and H2. Compared to raw sunflower oils, the properties of hydrocarbon fuels including the dynamic viscosity, pH, moisture content, density, oxygen content and heating value were improved.

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%.

Catalytic cracking of inedible camelina oils to hydrocarbon fuels over bifunctional Zn/ZSM-5 catalysts

Catalytic cracking of camelina oils to hydrocarbon fuels over ZSM-5 and ZSM-5 impregnated with Zn2+ (named bifunctional catalyst) was individually carried out at 500 °C using a tubular fixed-bed reactor. Fresh and used catalysts were characterized by ammonia temperature-programmed desorption (NH3-TPD), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and nitrogen isothermal adsorption/desorption micropore analyzer. The effect of catalysts on the yield rate and qualities of products was discussed. The loading of Zn2+ to ZSM-5 provided additional acid sites and increased the ratio of Lewis acid site to Brønsted acid site. BET results revealed that the surface area and pore volume of the catalyst decreased after ZSM-5 was impregnated with zinc, while the pore size increased. When using the bifunctional catalyst, the pH value and heating value of upgraded camelina oils increased, while the oxygen content and moisture content decreased. Additionally, the yield rate of hydrocarbon fuels increased, while the density and oxygen content decreased. Because of a high content of fatty acids, the distillation residues of cracking oils might be recycled to the process to improve the hydrocarbon fuel yield rate.

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.

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.

Life-cycle assessment of oilseeds for biojet production using localized cold-press extraction.

As nonfood oilseed varieties are being rapidly developed, new varieties may affect agricultural production efficiency and life-cycle assessment results. Current, detailed feedstock production information is necessary to accurately assess impacts of the biofuel life-cycle. The life-cycle impacts of four nonfood oilseeds (carinata [ L. Braun], camelina [ L. Crantz], canola or rapeseed [ L.], and sunflower [ L.]) were modeled using Argonne National Laboratorys GREET model to compare feedstocks for renewable biojet production using cold-press oil extraction. Only feedstock-related inputs were varied, allowing isolation of feedstock influence. Carinata and camelina performed slightly better than other oilseed crops at most product stages and impact categories as a result of current, low-input agricultural information and new feedstock varieties. Between 40 to 50% of SO and NO emissions, ∼25% of greenhouse gas (GHG) emissions, and ∼40% of total energy consumption for the biojet production impact occurred during feedstock production. Within the first standard deviation, total well-to-tank emissions varied between ∼13% (GHG) and ∼35% (SO) for all feedstocks emphasizing the importance of accurate agricultural production information. Nonfood oilseed feedstock properties (e.g., oil content, density) and agricultural management (e.g., fertilization, yield) affect life-cycle assessment results. Using biofuels in feedstock production and focusing on low-impact management would assist producers in improving overall product sustainability.

Effects of cold press operating conditions on vegetable oil fatty acid profiles

ABSTRACT Although most of jet fuels are currently made from petroleum, nonfood oilseeds such as flax and canola seeds may be an alternative for renewable jet fuel production in the near future. Vegetable oils produced from those oilseeds can be upgraded to liquid hydrocarbons to produce renewable jet fuels. The production efficiency and cost are heavily relied on the vegetable oil fatty acid profile (FAP). Previous research indicated that vegetable oil FAP is affected by oilseed species and oil extraction conditions. Cold press oil extractions from flax and canola seeds were conducted. The effect of the frequency controlling the screw rotating speed on the oil extraction efficiency and quality was discussed. Characterization of the vegetable oils produced, including density, pH value, viscosity, moisture, element component, heating value and FAP, was carried out. The residual oil contents left in the cold press meals were also determined. The results show that the oil extraction efficiency of oilseeds increased when the frequency decreased. For flax and canola seeds, their highest oil extraction efficiency was the same (81.0%), which was both obtained at 15 Hz. The cold press frequency had a minor influence on the FAPs of flax oils. However, the FAPs of canola oils produced at 15 Hz were different from those produced at 20 Hz and 25 Hz to some extent. The main fatty acid in flax and canola oils was linolenic acid and erucic acid, respectively.

Catalytic cracking of sunflower oils over ZSM-5 catalysts

Abstract. Because not conflict with human and animal food resources, non-food vegetable oils are promising sources for developing liquid advanced biofuel. Directly upgrading non-food vegetable oils to hydrocarbon fuels is likely offering reasonable profit margin for bio-jet fuel production. The sunflower oil extracted from residues that were produced in sunflower seed de-hulled processing is inedible due to its quality not meeting food standards. Genetically modified sunflower grown on margin lands can also provide one possible non-food source for sustainable biofuel production source since it doesn’t compete with the use of arable lands. Sunflower oils produced from those non-food sources were cracked on ZSM-5 catalysts in a fixed-bed reactor at three temperatures, 450 °C, 500 °C, and 550 °C. Characterization of the upgraded sunflower oils, advanced hydrocarbon fuel and distilled residual fuel, including pH value, density, water content, viscosity, heating value, and fatty acid profile, was carried out. The composition of non-condensable gases generated during the catalytic cracking process was also analyzed. The effect of the reaction temperatures on the upgraded sunflower oils’ yield and quality was discussed. The results showed that reaction temperatures affected the yield and properties of upgraded sunflower oils. The highest yield of advanced hydrocarbon fuel from raw sunflower oils was 21.1% at 550 °C. Upgraded sunflower oils were a mixture of un-cracked oils and hydrocarbons. After distillation, the advanced hydrocarbon fuel had lower viscosity, moisture content and density. The non-condensable gases contained C 1 – C 5 light hydrocarbons, H 2 , CO, CO 2 , etc. The reaction temperatures had significant effect on the concentrations of these compounds during catalytically cracking sunflower oils.

Effects of cold press operation conditions on fatty acid profiles of non-food vegetable oils

Abstract. Bio-jet fuel produced from non-food oilseeds can be an alternative to fossil fuels with the benefits of increasing national energy security, less impact on environment, and fostering rural economic growth. Efficient oil extraction from oilseeds is critical for the production of bio-jet fuels. In this study, oil extractions from camelina and canola (Brassica napus) seeds were conducted using a cold press method. The effect of the frequency controlling the screw rotating speed on the oil yield and quality was discussed. Characterization of the produced raw vegetable oils, including pH value, density, water content, viscosity, heating value, element component, and fatty acid profile, was carried out. The remaining oil contents left in the cold press meals were also determined. The results show that the oil recovery increased when the frequency decreased. The highest oil recoveries for camelina and canola seeds were 88.2% and 84.1% respectively, both at 15 HZ. The cold press frequency and processing temperature (97.2 °C - 106.0 °C) had minor influence on the quality and yield of both camelina and canola oils. In addition, camelina oil produced at 15 HZ was catalytically cracked to examine the potential of upgrading to hydrocarbon fuels. It was observed that some of oil physicochemical properties were improved after catalytic cracking. Though more study is needed for further improvement of oil recovery and quality, cold press could be an efficient method for oil extraction from non-food oilseeds and the oil produced is promising for future bio-jet fuel production.