A non-isothermal kinetic analysis of kaolinite dehydroxylation was carried out using thermogravimetric analysis on powder samples with heating rates from 1 to 30 °C・min-1 in a dynamic air atmosphere. The mechanism of the reaction, values of overall activation energy and pre-exponential factor were determined from a series of thermogravimetric experiments by the Coats- Redfern method. The results show that the dehydroxylation of kaolinite is controlled by the rate of the third-order reaction (F3) with the mean values of overall activation energy (EA) 255 kJ・mol-1 and pre-exponential factor (A) 25.56 × 1014 s-1.
Three filtration systems using the tractor hydraulic circuit were proposed and verified during the tractors operation. Using the tractor-implement hydraulic system and filter body with accessories the universally useful filtration systems were designed. The designed filtration systems are the second stage of universal oil filtration whereas the first stage is the standard tractor filter. The decrease in the content of iron reached the values 25.53 %, 32.95 % and 41.55 % and the average decrease in oil contamination characterized by average value of decrease in content of iron, copper and silicium reached values 24.3 %, 24.7 % and 35.53 % in dependence on the filtration system and an oil contamination level. The decrease in contamination level verified the ability of designed filtration systems for agricultural tractors.
Abstract. Nowadays the biomass or more precisely biofuel is more and more being exploited as a substitute for fossil fuels for heating as well as for example for heating of drying surroundings. The contribution is focused on reviewing of heat source by the combustion of various kinds of solid biofuels. It is a boiler VIGAS 25 with regulation AK 2,000 for heating the house and boilers VESKO-B and RH 4000. For the measurement of gaseous emissions was used device TESTO 330-2LL and other facilities. Firewood, peat briquettes, briquettes from the bark and hardwood briquettes were burned. Results of experimental measurements of production of gaseous emissions are processed in the tables and graphs depending on the performance of the boiler and the combustion time. Quantity of production of gaseous emissions depends mainly on the amount and uniformity of the fuel, the relative humidity of fuel, type of fuel and keeping the fuel mix prescribed by the manufacturer of the boiler. Found concentrations of gaseous emissions showing compliance with the statutory emission limits.
Vitázek I., Klúčik J., Uhrinová D., Mikulová Z., Mojžiš M. (2016): Thermodynamics of combustion gases from biogas. Res. Agr. Eng., 62 (Special Issue): S8-S13.Biogas as a respected source of renewable energy is used in various areas for heating or in power cogeneration units. It is produced by anaerobic fermentation of biodegradable materials. The utilization of biogas is wide -from process of combustion in order to obtain thermal energy, combined heat and power production, gas combustion engines, micro turbines or fuel cells up to trigeneration. Biogas composition depends on the raw material. The aim of this paper was to develop a new methodology; according to this methodology, by means of gas mixture thermodynamics and tabular exact parameters of individual gaseous components, all the necessary thermodynamic and operating values of biogas composition were calculated. The mathematical model of biogas combustion was elaborated. For an accurate realization of calculation, a computing program was designed.
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