Search

Correction for ‘Conversion of landfill gas to liquid fuels through a TriFTS (tri-reforming and Fischer–Tropsch synthesis) process: a feasibility study’ by Xianhui Zhao et al., Sustainable Energy Fuels, 2019, 3, 539–549.

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 carinata oil over Zn/Na-ZSM-5 catalyst in a fixed-bed reactor at 450 °C was carried out to produce hydrocarbon biofuel. The effect of Zn/Na-ZSM-5 catalyst on the yield and quality of the hydrocarbon biofuel was discussed. The yield of hydrocarbon biofuel, distillation residual, coke and gas was analyzed. Characterization of the hydrocarbon biofuel including density, moisture content, viscosity, higher heating value (HHV) and main components was carried out. In addition, the components of gas were analyzed. The yield of hydrocarbon biofuel and gas was 43.66% and 18.84%, respectively. After the carinata oil upgrading, some properties of the hydrocarbon biofuel including density, viscosity and HHV were improved. The hydrocarbon biofuel contained more than 90% hydrocarbons while it still contained a small amount of oxygenated compounds such as aldehyde, ether and ester. The produced distillation residual might be recycled for further catalytic cracking to increase the hydrocarbon biofuel yield. The produced gas including H 2 , CO and light hydrocarbons might be reused as syngas for ether power generation or production of value chemicals.

Catalytic fast pyrolysis (CFP) is proven one of the most promising processes for effectively converting biomass to liquid advanced biofuels. The yield and quality of biofuels are depended on biomass species, reactor type, operating conditions (such as temperature, pressure, heating rate, etc.) as well as the presenting of appropriate catalysts. Based on current CFP research, a hypothesis of biomass precision pyrolysis was proposed. A novel accurate control catalyst fast pyrolysis (ACCFP) reactor was invented and tested for exploration of biomass precision pyrolysis possibility. Various lignocellulosic biomass materials such as switchgrass, corn stover, prairie cordgrass, and pine sawdust were tested. The effects of reaction temperature, pressure, and heating rate on pyrolysis products (bio-oil, bio-char, and biosyngas) were investigated. ZSM-5 combined with various metal catalysts were applied in the ACCFP process. The pyrolysis products (bio-oil, bio-char, and biosyngas) produced were characterized for their physicochemical properties such as total acid number (TAN), water content, density, pH value, viscosity, higher heating value, and/or chemical composition. The results indicated that it is possible to accurately control CFP processing conditions to produce target bioproducts, which may lead to biomass precision pyrolysis. Compared to conventional pyrolysis, the ACCFP process could improve pyrolysis products yields and quality, such as greatly reducing oxygen content in the bio-oils produced. Although further research is needed, the study confirms that precision biomass pyrolysis may be an effective pathway for converting lignocellulosic biomass to advanced biofuels or chemicals.

Vacuum surcharge preloading for stabilizing soft soil foundation is becoming an increasingly popular ground improvement technique. Although many studies have been reported in literatures, few articles adopted the centrifuge model test. The Centrifuge model test technique is adopted to simulate a gravity field by changing centrifugal acceleration, in order to simulate the related conditions of many geotechnical structures. View of current research of centrifuge model test of the vacuum surcharge preloading, the paper describe the design of the vacuum surcharge preloading and the whole construction of the centrifuge model test which simulate the actual working conditions, based on the project near the Hengshui Lake and contain very soft clays which have undesirable geotechnical properties such as low bearing capacity and high compressibility. Through the centrifuge model test, the change of the earth pressure and the ultimate settlement of two years after construction were obtained. By analysis the results, it make a conclusion that the method of vacuum surcharge preloading is a more effective method.

To address the issues of greenhouse gas emissions associated with fossil fuels, vegetable oilseeds, especially non-food oilseeds, are used as an alternative fuel resource. Vegetable oil derived from these oilseeds can be upgraded into hydrocarbon biofuel. Catalytic cracking and hydroprocessing are two of the most promising pathways for converting vegetable oil to hydrocarbon biofuel. Heterogeneous catalysts play a critical role in those processes. The present review summarizes current progresses and remaining challenges of vegetable oil upgrading to biofuel. The catalyst properties, applications, deactivation, and regeneration are reviewed. A comparison of catalysts used in vegetable oil and bio-oil upgrading is also carried out. Some suggestions for heterogeneous catalysts applied in vegetable oil upgrading to improve the yield and quality of hydrocarbon biofuel are provided for further research in the future.

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.

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.

A catalyst of 10% Ni/γ-Al 2 O 3 for CO 2 /CH 4 reforming was prepared and characterized by TPR, TPD, XPS, XRD and activity measurements. XPS and TPR showed that Ni mainly exists in the form of NiAl 2 O 4 in the calcined catalyst and is hard to reduce below 650°C, indicating a strong interaction between metal and support. Reduction of the calcined catalyst results in fine particles of Ni 0 , with an average diameter of about 20 nm as determined by XRD. The uptake of H on the reduced catalyst measured by H 2 -TPD is 4.2–4.6 mole per mole of Ni species and does not depend on the reduction degree of Ni species. This provides a convincing piece of evidence for the occurrence of hydrogen spillover in the reduced catalyst. Only reduced catalysts present good activity, but the degree of nickel reduction has almost no effect on the reforming activity. This seems to suggest that Ni 0 is vital for the reforming activity, but γ-Al 2 O 3 is also involved in CO 2 /CH 4 reforming and contributes even more. Based on the mechanism proposed by Bradford et al. and on our observations, a mechanistic model has been proposed to elucidate the role of γ-Al 2 O 3 in CO 2 /CH 4 reforming.

Biomass is known as the only source for production of renewable liquid transportation biofuels. Lignocellulosic biomass has an advantage over other biofuel feedstocks, such as corn starch, soybeans, and sugar cane, because it can be produced quickly and at significantly low cost but not to compete to food crops. Nonetheless, transportation and storage are still big issues for sending lignocellulosic biomass feedstocks to bio-refinery facility to be converted into biofuels due to their low bulk density, high moisture, and biodegrading properties. The presenting study was trying to address those issues by torrefaction pretreatment. Torrefaction of corn stover, switchgrass, and prairie grass was carried using a lab scale batch reactor. The reactor was heated up to the selected temperature (250°C, 300°C, or 350°C) and kept at the final temperature for a period of 3 hours. The effect of raw materials and temperatures on the properties of the torrefied products (solid bio-char, liquid bio-oil, and gaseous syngas) was analyzed. These products were characterized with heating value, pH value, moisture content, etc. The heating values of bio-char increased with temperature of torrefaction while the yields on a weight basis decreased. The bio-chars produced have hydrophobic properties and higher heating values than the raw materials.

Biofuel is an alternative to fossil fuels with benefits of less impact on environment, national energy security, and rural economic growth. Fuel ethanol and biodiesel industries have grown fast all over the world in recent years. However, very fewer biofuels have been applied in aviation fuels because there are still many technical challenges for biofuels meeting the strict requirement of aviation fuels, such as low temperature, fluidity, high energy density, compatibility with materials of aircraft engine, etc. This study is aiming on exploring a sustainable pathway of jet fuel production from non-food vegetable oils. The Jet fuels produced could be applied in commercial airplanes or navy and air force aircrafts. Oil extraction from oilseeds is a critical step in the pathway. The tests of oil extraction from non-food sunflower seeds, sunflower meats, and fine sunflower meats were conducted by using a cold press in the study. The frequency controlling screw rotating speed of the cold press and processing temperature were discussed. The characterization of the raw oils produced was carried out. The effects of frequency and temperatures on oil properties such as density, pH value, viscosity, moisture content, CHNO contents, and organic compounds were examined. Oil remained in the processing residual meals was also determined by using solvent extraction method. The results show that higher oil extraction efficiency was obtained at related lower frequency. Processing temperatures had significant effects on the cold press performance. When the temperature was higher than 90°C or lower than 40°C, the cold press couldn’t work properly. The highest oil extraction efficiency for sunflower seeds, sunflower meats and fine sunflower meats in the tests were 75.67%, 89.74% and 83.19% respectively. Though further study is needed for the improvement of processing cost and efficiency, cold press could be one of efficient methods for oil extraction from various non-food oilseeds.

The massive consumption of fossil fuels and associated environmental issues are leading to an increased interest in alternative resources such as biofuels. The renewable biofuels can be upgraded from bio-oils that are derived from biomass pyrolysis. Catalytic cracking and hydrodeoxygenation (HDO) are two of the most promising bio-oil upgrading processes for biofuel production. Heterogeneous catalysts are essential for upgrading bio-oil into hydrocarbon biofuel. Although advances have been achieved, the deactivation and regeneration of catalysts still remains a challenge. This review focuses on the current progress and challenges of heterogeneous catalyst application, deactivation, and regeneration. The technologies of catalysts deactivation, reduction, and regeneration for improving catalyst activity and stability are discussed. Some suggestions for future research including catalyst mechanism, catalyst development, process integration, and biomass modification for the production of hydrocarbon biofuels are provided.

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.

Colored iron oxide thin films were prepared using Sol-gel technique. The raw materials were tetraethyl orthosilicate (TEOS), etoh ehanol (EtOH), iron nitrate, and de-ionized water. Various properties were measured and analysed, including the colour of thin films, surface topography, UV-Visible spectra, corrosion resistance and hydrophobicity. To understand how these properties influenced the structural and optical properties of Fe2O3 thin films, Scanning Electron Microscope (SEM), UV Spectrophotometer and other facilities were employed. Many parameters influence the performance of thin films, such as film layers, added H2O content, and the amount of polydimethylsiloxane (PDMS). When the volume ratio of TEOS, EtOH and H2O was 15: 13: 1, the quality of Fe(NO3)3·9H2O was 6g, and pH value was 3, reddish and uniform Fe2O3 thin films with excellent properties were produced. Obtained thin films possessed corrosion resistance in hydrochloric acid with pH=l and the absorption edge wavelength was ~350.2nm. Different H2O contents could result in different morphologies of Fe2O3 nanoparticles. When 1.5 ml PDMS was added into the Sol, thin films possessed hydrophobiliry without dropping. Coating with different layers, thin films appeared different morphologies. Meanwhile, with the increment of film layers, the absorbance increased gradually.