Catalytic hydrodeoxygenation (HDO), is an effective process to convert oxygenated compounds to hydrocarbons. This process is widely used for improving the negative properties of biomass-derived pyrolysis oils (bio-oils) such as high acidity, poor stability, and low heating value. During this process oxygen is removed from the bio-oil in the form of water, thus the liquid product of HDO process consists of aqueous phase and hydrocarbon phase that can be easily separated. Synthesis of efficient HDO catalyst has been a major challenge in the field of bio-oil upgrading. Red mud, which is an alkaline waste from alumina industry was used to develop a new red mud-supported nickel catalyst (Ni/RM) for the HDO of pinyon-juniper catalytic pyrolysis oil. The new catalyst was more effective than the commercial Ni/silica-alumina catalyst for the HDO of organic phase pyrolysis oil, the aqueous phase pyrolysis oil, and bio-oil model compounds. Less hydrogen was consumed in the case of Ni/RM and more liquid hydrocarbon yield was obtained compared to the commercial catalyst. In addition to HDO reactions, the Ni/RM catalyst catalyzed ketonization and carbonyl alkylation reactions that was important to produce liquid hydrocarbon from low molecular weight oxygenated compounds. Unlike the commercial catalyst, Ni/RM was regenerable by burning off the deposited coke and activation by reduction using hydrogen.

Sustainable energy sources are of great importance, and will become even more important in the future. Gasification of biomass is an important process for utilization of biomass, as a renewable energy carrier, to produce fuels and chemicals. Density functional theory (DFT) calculations were used to investigate i) the effect of co-adsorption of water and CO on the Ni(111) catalysed water splitting reaction, ii) water adsorption and dissociation on Ni(111), Ni(100) and Ni(110) surfaces, as well as iii) formyl oxidation and dissociation, iv) hydrocarbon combustion and synthesis, and v) the water gas shift (WGS) reaction on these surfaces. The results show that the structures of an adsorbed water molecule and its splitting transition state are significantly changed by co-adsorption of a CO molecule on the Ni(111) surface. This leads to less exothermic reaction energy and larger activation barrier in the presence of CO which means that far fewer water molecules will dissociate in the presence of CO. For the adsorption and dissociation of water on different Ni surfaces, the binding energies for H2O and OH decrease in the order Ni(110) > Ni(100) > Ni(111), and the binding energies for O and H atoms decrease in the order Ni(100) > Ni(111) > Ni(110). In total, the complete water dissociation reaction rate decreases in the order Ni(110) > Ni(100) > Ni(111). The reaction rates for both formyl dissociation to CH + O and to CO + H decrease in the order Ni(110) > Ni(111) > Ni(100). However, the dissociation to CO + H is kinetically favoured. The oxidation of formyl has the lowest activation energy on the Ni(111) surface. For combustion and synthesis of hydrocarbons, the Ni(110) surface shows a better catalytic activity for hydrocarbon combustion compared to the other surfaces. Calculations show that Ni is a better catalyst for the combustion reaction compared to the hydrocarbon synthesis, where the reaction rate constants are small. It was found that the WGS reaction occurs mainly via the direct pathway with the CO + O → CO2 reaction as the rate limiting step on all three surfaces. The activation barrier obtained for this rate limiting step decreases in the order Ni(110) > Ni(111) > Ni(100). Thus, the WGS reaction is fastest on the Ni(100) surface if O species are present on the surfaces. However, the barrier for desorption of water (as the source of the O species) is lower than its dissociation reaction on the Ni(111) and Ni(100) surfaces, but not on the Ni(110) surface. Therefore the direct pathway on the Ni(110) surface will dominate and will be the rate limiting step at low H2O(g) pressures. The calculations also reveal that the WGS reaction does not primarily occur via the formate pathway, since this species is a stable intermediate on all surfaces. All reactions studied in this work support the Brønsted-Evans-Polanyi (BEP) principles.

The production of hydrogen (H2) and methane (CH4) related to olivine hydration (i.e. serpentinization) is considered a major contributor to abiotic hydrocarbon synthesis on Earth. Recent discoveries have highlighted the importance of low temperature (<100oC) serpentinization at continental peridotite outcrops. Such sites produce substantial fluxes of abiotic CH4 from gas seeps and/or springs. A limited number of studies in the southern hemisphere offer research on low temperature abiotic hydrocarbon synthesis in natural ultramafic environments, though large areas of exposed ophiolite are prevalent. This study assesses the origin and flux of CH4 and related water-rock interactions from a previously undiscovered site in the Dun Mountain Ophiolite Belt (DMOB), located at Red Hills, New Zealand. Methane emissions from a hyper-alkaline (pH >11.6) and reduced spring of calcium hydroxide (Ca2+-OH-) type waters near the Maitlands Fault were between 730 to 17,000 mg m 2day 1. The δ13C and δD values of CH4 emitting from this spring are consistent with CH4 of abiotic origin (δ13C: 32.7 ‰ VPDB, δD: 363 ‰ V SMOW). Hyper-alkaline fluids emitting from the spring are concentrated in dissolved CH4 (2.2 mg/L) and H2 (0.7 mg/L) and display δ13CCH4 signatures consistent with other sites worldwide. Extensive and localised carbonate precipitation occurs at the hyper-alkaline Ca-rich spring. Isotopic evaluation of carbonate nodules are kinetically fractionated with 13C and 18O depletions up to 30.8 ‰ and 9.3 ‰, respectively. This disequilibrium between the mineralogy and interacting fluids and gases represents a potential habitable environment for microorganisms. Porous, layered carbonates located on the outer edges of the hyper-alkaline spring are the result of atmospheric CO2 interaction with magnesium bicarbonate (Mg2+-HCO3) and Ca2+-OH- hyper-alkaline waters. The precipitation of these carbonates offers potential insight towards low temperature CO2 sequestration. Additionally, various forms of Fe-rich amorphous material precipitate in association with Mg2+-HCO3 type waters at the Red Hills. The identification of bacteria and diatoms within this material offers supporting information regarding microbial survival in metal-rich, reduced environments. This multidisciplinary study demonstrates the interconnected nature of geological, biological and atmospheric interactions in ultramafic environments at low temperature on Earth.

Master's Thesis is focused on production of CO2 from fossil fuels combustion and the methods of CO2 emission from fossil fuels combustion reduction, resp. pre-combustion and post-combustion separation of CO2. Recapitulation of world consumption of primary energetic resources and carbon dioxide production as a result of theirs combustion in years 1971 - 2006 was made using a number of information sources. Whilst combustion o fossil fuel is related with production of CO2, calculation of emission rate of CO2 from fossil fuels (natural gas, crude oil and coal) was demonstrated. The Case Study of energy and material balances of gas turbine cycle with synthesis of methane from CO2 and from hydrogen which is produced in water splitting was made, using CHEMCAD software.