Transportation sector CO2 emissions contribute to global warming. Methanol generated from clean energy sources has been proposed as a transportation fuel as an alternative to gasoline or diesel to reduce emissions. Catalytic methanol-steam reformers can be combined with high temperature polymer electrolyte membrane (HTPEM) fuel cell systems to create compact electrical power modules which run on liquid methanol. These modules combine the efficiency of a fuel cell system with the convenience of using a traditional, liquid hydrocarbon fuel. Catalytic methanol-steam reformers require a heat source as the methanol-steam reforming process is endothermic. The heat source for this system will initially be from the catalytic combustion of either pure methanol, during startup, or from HTPEM fuel cell anode waste gas during system operation. Efficient use of catalyst requires effective premixing of the fuel and air. This study will investigate parameters affecting premixing and their effect on temperature distributions and emissions.

Methylosinus trichosporium OB3b is a wild type, obligate methanotroph that grows only on one-carbon compounds and, in the absence of copper, produces high levels of soluble methane monooxygenase (sMMO) to metabolize methane to methanol. SMMO has gained a great deal of attention in the bioremediation and chemical industries because of its low substrate specificity and its ability to oxidize chlorinated hydrocarbons. Much literature exists on cultivating this organism on methane, however no one has achieved dry cell weight densities exceeding 18 g/L. Biomass growth is limited due to mass transfer of methane to cells. This study investigated the growth of M. trichosporium on the water soluble carbon source, methanol while retaining sMMO activity. Methanol was found to completely inhibit growth at 40 g/L. For online methanol measurements during fed-batch cultivation, an in situ probe was constructed from autoclavable materials and equipped with a Figaro TGS822 vapor sensor. The probe was designed to prevent the sensor coming in contact with water aerosols which affect its performance. The probe was an essential component of a feedback methanol control system. The cumulative CO2 production (CCP) strategy was used to feed methanol in fed-batch experiments. In an initial bioreactor study, growth nutrients were fed in excess. The yields of biomass to nutrients were determined and the growth medium modified accordingly. A biomass density of 19 g/L (growth rate of 0.013-0.065 h-1) was achieved with sMMO activity of 300 to 500 [µmol naphthol][g of biomass]-1[h]-1. The subsequent bioreactor study involved feeding of nutrients based on their yields in relation to methanol, a biomass density of 62 g/L (growth rate of 0.034- 0.08 h-1) was achieved. The inoculum cultures utilized in the bioreactor studies were maintained on Noble agar plates containing nitrogen minimal salts medium and methane. After 6 months of subsequent plate transfers, M. trichosporium lost the ability to produce high levels of sMMO. The enzyme activity in methanol grown cells was recovered by subculturing in liquid NMS medium with methane as the sole carbon source, the activity increased from 8 to 600 [µmol naphthol][g of biomass]-1[h]-1. It is recommended that further studies be carried out on stimulating sMMO activity during cultivation on methanol. / Thesis (Master, Chemical Engineering) -- Queen's University, 2008-08-21 15:14:42.475

This research investigates a novel approach to methanol production from methane. The high use of fossil fuels in New Zealand and around the world causes global warming. Using clearer, renewable fuels the problem could potentially be reduced. Biomass energy is energy stored in organic matter such as plants and animals and is one of the options for a cleaner, renewable energy source. A common biofuel is methane that is produced by anaerobic digestion. Although methane is a good fuel, the energy is more accessible if it is converted to methanol. While technology exists to produce methanol from methane, these processes are thermo-chemical and require large scale production to be economic. Nitrosomonas europaea, a nitrifying bacterium, has been shown to oxidize methane to methanol (Hyman and Wood 1983). This research investigates the possibility of converting methane into methanol using immobilized N. europaea for use in smaller applications. A trickle bed bioreactor was developed, containing a pure culture of N. europaea immobilized in a biofilm on ceramic raschig rings. The reactor had a biomass concentration of 7.82 ± 0.43 g VSS/l. This was between 4 – 15 times higher than other systems aimed at biologically producing methanol. However, the immobilization dramatically affected the methanol production ability of the cells. Methanol was shown to be produced by the immobilized cells with a maximum production activity of 0.12 ± 0.08 mmol/gVSS.hr. This activity was much lower than the typical reported value of 1.0 mmol/g dry weight.hr (Hyman and Wood 1983). The maximum methanol concentration achieved in this system was 0.129 ± 0.102 mM, significantly lower than previous reported values, ranging between 0.6 mM and 2 mM (Chapman, Gostomski, and Thiele 2004). The results also showed that the addition of methane had an effect on the energy gaining metabolism (ammonia oxidation) of the bacteria, reducing the ammonia oxidation capacity by up to 70%. It was concluded, because of the low methanol production activity and the low methanol concentrations produced, that this system was not suitable for a methanol biosynthesis process.

Water electrolysis is one of the first methods used to generate hydrogen and is thus not considered to be a new technology. With advances in proton exchange membrane technology and the global tendency to implement renewable energy, the technology of water electrolysis by implementation of proton exchange membrane as solid electrolyte has developed into a major field of research over the last decade. To gain an understanding of different components of the electrolyser it is best to conduct a performance analysis based on hydrogen production rates and polarisation curves. The study aim was to compare the technologies of membrane electrode assembly with gas diffusion electrode and the proton exchange membranes of Nafion® and polybenzimidazole in a commercial water electrolyser. To determine which of the components are best suited for the process a laboratory scale electrolyser was to be used to replicate the commercially scaled performance. The effect of feed water contaminants on electrolyser performance was also investigated by introducing iron and magnesium salt solutions and aqueous methanol solutions in the feed reservoir. Components to be tested included different PEM types as well as the base component on which the electrocatalyst layer is applied. The proton exchange membranes compared were standard Nafion® N117 and polybenzimidazole meta-sulfone sulfonated polyphenyl sulfone (PBI-sPSU). A laboratory scale electrolyser from Giner Electrochemical Systems was utilised where different components were tested and compared with one another. Experimental results with commercial membrane electrode assemblies and gas diffusion electrodes demonstrated the influence of temperature on electrolyser performance for the proton exchange membranes, where energy efficiency increased with temperature. The effect of pressure was insignificant over the selected pressure range. Comparison of membrane electrode assembly and gas diffusion electrode technologies showed enhanced performance from MEA technology, this was most likely due to superior electrocatalyst contact with the PEM. Results of synthesised Nafion® N117 and PBI-sPSU MEA showed increased performance for PBI-sPSU, but it was found to be more susceptible to damage under severe conditions. The effect of metal cations in the supply reservoir exhibited reduced energy efficiencies and increased specific energy consumption for the test duration. Treatment with sulphuric acid was found to partially restore membrane electrode assembly performance, though it is believed that permanent damage was inflicted on the membrane electrode assembly electrocatalyst. Use of aqueous methanol solutions were found to increase electrolyser performance. It was also found that aqueous methanol electrolysis occurs at lower current densities, whereas a combination of aqueous methanol and water electrolysis occurred at higher current densities depending on the concentration of methanol. / Thesis (MIng (Chemical Engineering))--North-West University, Potchefstroom Campus, 2013.

Ethylene and propylene are important chemical feedstocks for the production of polyethylene and polypropylene. Ethylene and propylene can be produced by various methods including steam cracking of liquefied natural gas (LNG), naphta or light olefin fractions. The methanol to olefin (MTO) process provides an alternative means of producing ethylene and propylene, where ZSM-5 is frequently used as catalyst due to its hydrophobicity, strong acidity, molecular sieve properties and low tendency towards coking, which makes ZSM-5 one the most popular zeolite catalysts in the industry. The oil crisis 1973 and the second oil crisis in 1978 caused the development of a commercial MTO process. Mobil Research and Development Corporation built a fixed-bed pilot plant to demonstrate the feasibility of the MTO as well as methanol-to-gasoline (MTG) process. When the oil price dropped again during the 1980’s, further developments of commercial processes were stopped for the time being. However, investigations on a bench scale are still pursued, and applications for patents are still submitted. During this study ZSM-5 was synthesized with a hydrothermal method, which produced agglomerated polycrystalline grains with characteristic ZSM-5 morphology and a Si/Al ratio of approximately 40. The synthesis time, synthesis temperature and aging time were varied while keeping all the other synthesis parameters constant in order to determine their influence on crystallite size. The synthesis time was varied between 12-72 hours, synthesis temperature was varied between 130-170°C and aging time between 30-90 minutes. Using SEM to determine crystal size, it was found that a variation in the aging time produced the largest crystallites (average of 21.6μm ± 10.8μm) while also having the largest influence on crystallite size followed by synthesis temperature (average of 13.1μm ± 4.9μm) and finally synthesis time (average of 5.7μm ± 0.4μm). In all cases XRD and SEM confirmed the formation of ZSM-5. To evaluate the as-synthesized ZSM-5 and compare it to a commercial ZSM-5 catalyst, Catalyst A using the MTO process, ZSM-5 was synthesized for 72 hours at 170°C with an aging time of 60 minutes before synthesis. The as-synthesized as well as Catalyst A’s agglomerated polycrystalline grains were sieved into three size fractions: smaller than 75μm, 75-150μm and 150-300μm. All six ZSM-5 fractions of ZSM-5 were used as catalysts for the MTO process in a fixed bed reactor at 400°C, atmospheric pressure and a 20wt% methanol to water feed. At 3.5 hours time on stream (TOS), the intermediate 75-150μm fraction had the highest light olefin selectivity for both the as-synthesized as well as Catalyst A, followed by the 150-300μm fraction and finally the smaller than 75μm fraction with the lowest light olefin selectivity. From this results it is clear that the as-synthesised ZSM-5 did not perform as well as Catalyst A. While the intercrystalline voids of the agglomerated ZSM-5 form second-order pores where self-diffusion is enhanced, the increased diffusional barriers created by the intercrystalline boundaries reduce the diffusion rate, promoting secondary reactions at the strong Brönsted acid sites thereby reducing ethylene and propylene selectivity. Coking reduces access to the Brönsted acid sites and plays a more influencial role for smaller crystallite sizes. Accordingly, the smaller than 75μm fraction had the lowest light olefin selectivity, while the 150-300μm fraction was probably least influenced by coking. The increased pathways for products and reagents in the 150-300μm fraction resulted in more secondary reactions taking place within this catalyst than the 75-150μm fraction explaining the superior performance of the 75-150μm fraction. Since the grain size determines the ratio of the external to the internal surface areas as well as the amount of intercrystalline boundaries in the catalyst, it follows that the catalytic activity and polycrystalline grain size ratio should actually be tailored when optimising the product distribution of the ZSM-5 catalysed MTO process. The as-synthesized ZSM-5 didn’t perform very well when compared to Catalyst A and modification of the synthesis method is recommended. / Thesis (MSc (Chemistry))--North-West University, Potchefstroom Campus, 2012.

Water electrolysis is one of the first methods used to generate hydrogen and is thus not considered to be a new technology. With advances in proton exchange membrane technology and the global tendency to implement renewable energy, the technology of water electrolysis by implementation of proton exchange membrane as solid electrolyte has developed into a major field of research over the last decade. To gain an understanding of different components of the electrolyser it is best to conduct a performance analysis based on hydrogen production rates and polarisation curves. The study aim was to compare the technologies of membrane electrode assembly with gas diffusion electrode and the proton exchange membranes of Nafion® and polybenzimidazole in a commercial water electrolyser. To determine which of the components are best suited for the process a laboratory scale electrolyser was to be used to replicate the commercially scaled performance. The effect of feed water contaminants on electrolyser performance was also investigated by introducing iron and magnesium salt solutions and aqueous methanol solutions in the feed reservoir. Components to be tested included different PEM types as well as the base component on which the electrocatalyst layer is applied. The proton exchange membranes compared were standard Nafion® N117 and polybenzimidazole meta-sulfone sulfonated polyphenyl sulfone (PBI-sPSU). A laboratory scale electrolyser from Giner Electrochemical Systems was utilised where different components were tested and compared with one another. Experimental results with commercial membrane electrode assemblies and gas diffusion electrodes demonstrated the influence of temperature on electrolyser performance for the proton exchange membranes, where energy efficiency increased with temperature. The effect of pressure was insignificant over the selected pressure range. Comparison of membrane electrode assembly and gas diffusion electrode technologies showed enhanced performance from MEA technology, this was most likely due to superior electrocatalyst contact with the PEM. Results of synthesised Nafion® N117 and PBI-sPSU MEA showed increased performance for PBI-sPSU, but it was found to be more susceptible to damage under severe conditions. The effect of metal cations in the supply reservoir exhibited reduced energy efficiencies and increased specific energy consumption for the test duration. Treatment with sulphuric acid was found to partially restore membrane electrode assembly performance, though it is believed that permanent damage was inflicted on the membrane electrode assembly electrocatalyst. Use of aqueous methanol solutions were found to increase electrolyser performance. It was also found that aqueous methanol electrolysis occurs at lower current densities, whereas a combination of aqueous methanol and water electrolysis occurred at higher current densities depending on the concentration of methanol. / Thesis (MIng (Chemical Engineering))--North-West University, Potchefstroom Campus, 2013.

<p>The direct methanol fuel cell or DMFC is emerging as a promising alternative energy source for many applications. Developed and developing countries, through research, are fast seeking a cheap and stable supply of energy for an ever-increasing number of energy-consuming portable devices. The research focus is to have DMFCs meeet this need at an affordable cost is problematic. There are means and ways of making this a reality as the DMFC is found to be complementary to secondary batteries when used as a trickle charger, full charger, or in some other hybrid fuel cell combination. The core functioning component is a catalyst containing MEA, where when pure platinum is used, carbon monoxide is the thermodynamic sink and poisons by preventing further reactions at catalytic sites decreasing the life span of the catalyst if the CO is not removed. Research has shown that the bi-functional mechanism of a platinum-ruthenium catalyst is best because methanol dehydrogenates best on platinumand water dehydrogenation is best facilitated on ruthenium. It is also evident that the addition of other metals to that of PtRu/C can make the catalyst more effective and effective and increase the life span even further. In addition to this, my research has attempted to reduce catalyst cost for DMFCs by developing a low-cost manufacturing technique for catalysts, identify potential non-noblel, less expensive metallic systems to form binary, ternary and quarternary catalysts.</p>

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2004. / Härtill 5 uppsatser.

Thesis (M.S.)--University of Delaware, 2007. / Principal faculty advisors: Jingguang G. Chen, Dept. of Chemical Engineering; and Thomas P. Beebe, Jr., Dept. of Chemistry & Biochemistry. Includes bibliographical references.

Freiburg i. Br., Univ., Diss., 2008.