In this study, the catalytic oxidation of methanol to formaldehyde was investigated in a laboratory-scale fixed-bed catalytic reactor, under a large number of different conditions. Iron-molybdate catalysts supported by silica or alumina with a molybdenium/iron (Mo/Fe) ratio of 1.5, 3 and 5 were studied for the gas phase reaction. In order to obtain the optimum conditions, six different temperatures in the range of 250-375°C and three different space times of 50.63, 33.75 and 20.25 g/(mol/h) were investigated. After determining the optimum conditions for this reaction, experiments aimed at understanding the reaction kinetics, were carried out. These experiments were performed on the catalyst favoring the formation of formaldehyde, which has a (Mo/Fe) ratio of 5 on a silica support. Seven reaction models derived by the mechanisms cited in the literature were tested to elucidate the kinetics of the reaction and the surface reaction controlling model was found to be the most suitable reaction mechanism.
The gas generated by anaerobic fermentation of organic wastes is called biogas. Since it contains methane, it can be burnt and so it can be used as an alternative energy source. The production of biogas is an anaerobic treatment process, it is important to understand the basic biochemistry and microbiology of anaerobic systems. This study demonstrates the kinetic study to find out the best microbial kinetics which will be necessary for the design of an anaerobic fermenter. For this purpose, chicken manure and chicken manure with inoculation culture were used. Experiments were operated under mesophilic conditions in laboratory type glass fermenters each having a volume of ten liters.
The global energy demand is increasing day by day. Fossil fuels such as crude oil, coal and gas are the main source of energy worldwide. However, fossil fuels, which cause acid rain, the greenhouse effect and other such environmental problems, will eventually be depleted, and renewable energy seems to be the most reasonable solution in this regard. Renewable biofuels have significant potential and can meet the world’s current energy demand. One of the important biofuels is biodiesel, and in the future it can replace petroleum. Waste cooking oil was used as a raw material in biodiesel production in order to reduce the production cost of the offered additive. In this study, the aim was to optimize the process parameters for biodiesel production within the acceptable limit values in the literature. Therefore, the molar ratio of methanol to waste cooking oil (9:1–15:1), catalyst concentration (1–5% by weight) and reaction time (60–120 min) were studied for two catalyst types, potassium hydroxide and ion exchange resin Amberlyst 15. The biodiesel obtained with maximum efficiency for each catalyst was also compared with the international biodiesel standards.
In this study, the catalytic combustion of a volatile organic compound (VOC) namely formaldehyde on manganese oxide catalysts supported on silica or alumina, and on an industrial catalyst, i.e. a mixture of copper oxide and zinc oxide, was studied in the temperature range 125 -225 °C. Formaldehyde was used as the aqueous solution. It was found that as the temperature was increased, the combustion of the produced and feed formaldehyde was enhanced whereas methanol combustion decreased. Also, the degree of conversion increased with the percentage of MnO in the catalysts.
Grass is a highly desirable substrate for anaerobic digestion because of its higher biodegradability and biogas/methane yield. It contains a large amount of organic matter, which can be digested anaerobically to produce biogas. Anaerobic co-digestion of grass, cow manure and sludge was studied under mesophilic conditions for 65 days. Experiments were performed on a feed ratio of grass/manure 5, 10, 15, 20, 25%, respectively. During the experiments the volume and concentration of biogas and methane were recorded daily. The maximum cumulative biogas and methane yield was obtained as 331.75 mLbiogas/gVS and 206.64 mLCH4/gVS for 25% ratio. Also, the results of the experiments were tested on the three different kinetics model which are the first order kinetic model, modified Gompertz model and Logistics model. As a result of the study, it was found that by using grass waste 1.2.109 kWh/year electricity may be produced and 1.106 tons/year CO2 greenhouse gas emission may be reduced.
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