Deoxygenation Of Biomass Research Articles

Investigating the multifunctional nature of bimetallic FeMoP catalysts using dehydration and hydrogenolysis reactions

Herein, we investigate the effects of altering the multifunctional nature of a series of FeMoP catalysts for biomass deoxygenation reactions. Unsupported FeMoP catalysts were synthesized at reduction temperatures between 650°C and 850°C. The reduction temperature used during the synthesis of FeMoP altered the surface properties of these materials (i.e., acidity and CO-titrated metal sites) while leaving the bulk crystal structure of FeMoP unaffected. This alteration in the surface properties significantly affected the catalytic performance of FeMoP materials in the deoxygenation reactions. The catalytic performance of the FeMoP catalysts was first investigated using the acid catalyzed, non-aqueous, dehydration of cyclohexanol. Aside from showing high selectivities to cyclohexene (>99%) for all catalysts, the experiments demonstrated that FeMoP-650 showed the highest initial rate due to the largest number of surface acid sites among these catalysts. In addition, these FeMoP catalysts were examined using the hydrodeoxygenation (HDO) of phenol. While all FeMoP catalysts were highly selective to benzene (∼90%) at conversions less than 15%, studies at higher conversions of phenol provided evidence that catalysts with a higher amount of acid sites maintained enhanced selectivity to benzene. Furthermore, the stability of FeMoP catalysts for phenol HDO was tested with a 48h time-on-stream (TOS) study. FeMoP exhibited excellent stability, as evidenced by the retention of the initial reaction rate, selectivity to benzene, and oxidation state of surface species throughout the TOS run.

Effects of phosphorus-modified HZSM-5 on distribution of hydrocarbon compounds from wood–plastic composite pyrolysis using Py-GC/MS

ZSM-5 zeolite is an efficient catalyst for both biomass deoxygenation and polyolefins cracking in pyrolysis process. In this study, wood–plastic composite (WPC), composed mainly of woody materials and thermoplastic polymers, was pyrolyzed using Py-GC/MS over phosphorus-modified HZSM-5 (P-HZSM-5) with varying P loadings (from 0 to 10wt.%). The catalysts were prepared by wet impregnation method and characterized by XRF, XRD and NH3-TPD. The effects of pyrolysis temperature, time, heating rate, catalyst to WPC ratio and P loadings on the hydrocarbon distribution of WPC pyrolysis were studied. Pyrolysis conditions have significant effects on hydrocarbon distribution. Parent HZSM-5 facilitated aromatics formation, while P-HZSM-5 favored the formation of light aliphatic hydrocarbons (C4-C12). The yields of C4-C12 increased first with rising pyrolysis temperature from 450 to 550°C, then decreased over 550°C. Similarly, C4-C12 yields increased during the pyrolysis time from 15 to 30s and decreased with the further prolonged time. A low heating rate (0.002°C/ms) favored the formation of light aliphatic hydrocarbons, while high heating rates (>0.2°C/ms) favored the formation of aromatics. Increasing catalyst to WPC ratio augmented aromatic selectivity. Hydrocarbon distribution strongly depended on the catalyst’s acidity, adjusted by varying P loading in P-HZSM-5. The highest yield of C4-C12 was obtained while using P-HZSM-5 with P loading of 3.5wt.%.

The production of renewable transportation fuel through fed-batch and continuous deoxygenation of vegetable oil derived fatty acids over Pd/C catalyst

Renewable fuels such as green diesel from renewable biomass have received attentions because of energy and environmental concerns. Deoxygenation, used to upgrade biomass derived oils has been applied intensively nowadays. To successfully improve this process, fed-batch and following continuous processes on real biomass derived fatty acids need to be investigated. In this study, liquid-phase deoxygenation of vegetable oil derived fatty acids was carried out over 5% Pd/C with cofeeding H2. With sufficient hydrogen, complete hydrogenation of unsaturated fatty acids occurred, leading to successive deoxygenation of the saturated fatty acids with n-alkane yields of 99% and 88% and average CO2 selectivity of 94.9% and 94.6% in the fed-batch and continuous mode, respectively. After hydrogenation is completed, lower than 5% of effective H2 partial pressure was found to be favorable for the decarboxylation pathway and ideal for deoxygenation of biomass derived fatty acids. Copyright © 2015 John Wiley & Sons, Ltd.

Understanding the role of TiO2crystal structure on the enhanced activity and stability of Ru/TiO2catalysts for the conversion of lignin-derived oxygenates

Although Ru catalysts supported on reducible oxides such as TiO2 hold significant promise for the deoxygenation of biomass derived oxygenates, a significant drawback is their instability under oxidation conditions necessary for catalyst regeneration. In this contribution, the role of TiO2 crystal structure on resistance to metal particle sintering during calcination treatments at 400 and 500 °C is investigated. The resulting impact of the calcination temperature and TiO2 support phase for the conversion of guaiacol at 400 °C under atmospheric pressure of hydrogen over supported Ru catalysts is presented. Results suggest that the rutile TiO2 phase plays an important role in stabilizing Ru particles during calcination pretreatment in comparison with anatase supported Ru catalysts. Furthermore, rates normalized to the area of the support and the Ru suggest that the high activity of Ru/TiO2 systems for guaiacol conversion is attributed to defect sites created by hydrogen spillover from the Ru metal to the reducible TiO2 as opposed to only the sites located at the Ru/TiO2 interface.

Upgrading of biofuel by the catalytic deoxygenation of biomass

Biomass can be used to produce biofuels, such as bio-oil and bio-diesel, by a range of methods. Biofuels, however, have a high oxygen content, which deteriorates the biofuel quality. Therefore, the upgrading of biofuels via catalytic deoxygenation is necessary. This paper reviews the recent advances of the catalytic deoxygenation of biomass. Catalytic cracking of bio-oil is a promising method to enhance the quality of bio-oil. Microporous zeolites, mesoporous zeolites and metal oxide catalysts have been investigated for the catalytic cracking of biomass. On the other hand, it is important to develop methods to reduce catalyst coking and enhance the lifetime of the catalyst. In addition, an examination of the effects of the process parameters is very important for optimizing the composition of the product. The catalytic upgrading of triglycerides to hydrocarbon-based fuels is carried out in two ways. Hydrodeoxygenation (HDO) was introduced to remove oxygen atoms from the triglycerides in the form of H2O by hydrogenation. HDO produced hydrogenated biodiesel because the catalysts and process were based mainly on well-established technology, hydrodesulfurization. Many refineries and companies have attempted to develop and commercialize the HDO process. On the other hand, the consumption of huge amounts of hydrogen is a major problem hindering the wide-spread use of HDO process. To solve the hydrogen problem, deoxygenation with the minimum use of hydrogen was recently proposed. Precious metal-based catalysts showed reasonable activity for the deoxygenation of reagent-grade fatty acids with a batch-mode reaction. On the other hand, the continuous production of hydrocarbon in a fixed-bed showed that the initial catalytic activity decreases gradually due to coke deposition. The catalytic activity for deoxygenation needs to be maintained to achieve the widespread production of hydrocarbon-based fuels with a biological origin.

Thermodynamic Equilibrium Analysis of Methanol Conversion to Aromatic Hydrocarbons Using SAS: A Prelude to Biomass Deoxygenation

Deoxygenation, or removal of oxygen from oxygenates, is a reaction of paramount importance in the production of hydrocarbon fuels from biorenewable substrates. A thermodynamic equilibrium analysis gives valuable insights into the theoretical limits of desired products when a substrate is reacted under a given set of conditions. Here we report the equilibrium composition of the methanol-to-gasoline hydrocarbon system by minimizing the total Gibbs energy of the system. Minimization was performed under constrained conditions using a non-linear optimization technique available in SAS. The system was treated as a gaseous mixture of ten components: C6H6, C7H8, C8H10 (ethyl benzene), C8H10 (xylene), CH3OH, H2O, C, CO2, CO, and H2. The carbon in the equilibrium mixture was used as a measure of coke formation, which causes deactivation of catalysts that are used in aromatization reactions. The equilibrium composition of methanol was analyzed for temperatures ranging from 400°C to 1200°C and gauge pressures of 0, 5, 10, and 15 atm. It was observed that when the temperature was increased, the system changed from negative to positive, making the deoxygenation reaction less spontaneous. The positive portion of the Gibbs free energy further increased when the pressure was increased from 0 to 15 atm.

Bioenergy II: Group 8 Metal Complexes as Homogeneous Ionic Hydrogenation and Hydrogenolysis Catalysts for the Deoxygenation of Biomass to Petrochemicals - Opportunities, Challenges, Strategies and the Story so Far

Biomass is characterized by a high oxygen content (typically ? 40 % w/w). Its conversion into feedstocks that can directly be used in existing petrochemical feed streams will therefore require an efficient and selective deoxygenation chemistry. Ruthenium or iron-based water/acid-tolerant and high-temperature stable metal complexes that are active ionic hydrogenation and hydrogenolysis catalysts maybe ideally suited for this purpose.

Direct Conversion of Sunflower Shells to Alkanes and Aromatic Compounds

Deoxy-liquefaction runs were performed at final temperatures of 350, 400, 450, and 500 °C, with only 10 wt % distilled water as medium. The influence of the final temperature on the properties of biopetroleum obtained from sunflower shell samples (with kernels 5 wt %) via deoxy-liquefaction was examined in relation to the yield and distribution of products (i.e., gas, solid, liquid), especially the compositions of oil products. Furthermore, the liquid oil with a maximum yield and H/C molar ratio of 1.99 and higher heating value (HHV) of 46.9 MJ/kg was obtained at 450 °C. The biopetroleum analyzed by gas chromatography−mass spectrometry (GC−MS) with the National Institute of Standards and Technology (NIST) 98 MS library was mainly composed of benzene derivatives, phenolic derivatives, and alkanes (C7−C19). What is special is that the content of (Z,Z)-9,12-octadecadienoic acid (RT = 21.26 min), which came from the few sunflower kernels decreased from 21.32% at 350 °C to zero at 500 °C. This suggested that deoxy-liquefaction in a closed system could realize not only the deoxygenation of biomass but the deoxygenation of linoleic acid by controlling the final temperature. Moreover, the biopetroleum obtained can be upgraded to transport fuel or separated for chemical products.