Paliva (Fuels) is a scientific journal issued quarterly by the Faculty of Environmental Technology, ICT Prague. Fuels publishes papers on a broad range of topics covering exploitation, processing, upgrading, and utilization of various types of fuels, and power engineering.
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Current issue

4/2013

Exhaust emissions from cold starts of passenger cars and light trucks

Jakub Šiška, Milan Pospíšil, Daniel Maxa, Pavel Šimáček, Petr Říha, Jiří Vavřina, Jan Karel

When driving vehicles with a cold engine, a large amount of exhaust pollution is released into the environment, which affects the total emission balance. The measurement of emissions from cold starts is experi-mentally quite expensive and time consuming, so look for a reliable and robust predictive mathematical model that would simplify the calculation of emissions. It was measured and validated core set of emission data (CO, CH, NOx) characterizing a cold start passenger cars a light trucks and designed a simple algorithm for predic-tion of cold start emissions.

4/2013 - pages 109 - 116download PDF file

Experimental measurement of exhaust emissions of trucks in the simulation at the road junctions traf

Jakub Šiška, Milan Pospíšil, Daniel Maxa, Pavel Šimáček, Petr Říha, Jiří Vavřina, Jan Karel

For the calculation of emissions from the junctions it exist an absolute lack of research works, from which it would be possible to draw the necessary data. This fact applies especially trucks, for which measurement of emission data is experimentally and financially quite a challenging task. It was designed and experimentally verified unique process to perform engine and emission tests for heavy duty vehicles through which we can obtain a very valuable and quite unique set of infor-mation on emission characteristics of the representatives of the fleet of trucks in the Czech Republic during specific driving modes in the area of the junction.

4/2013 - pages 117 - 122download PDF file

Testing of electric properties of ceramic components for thermally stressed parts of high-temperatur

Jan Berka, Antonín Rotek, Jan Vít

Heating elements are one of the important components of High Temperature Helium Loop. By means of heating elements the heating of test section of the loop to required temperature is provided even in high gas flow rates in the loop. The insulation of heating elements was manufactured of cordierite ceramics. With these elements the maximum projected temperature 900 °C could not be reached because of decreasing of electric resistance among the spirals. Therefore several tests were done in order to discover the reason of the problem. Consequently properties of new ceramic material based on corundum for manufacturing of the new heating elements were verified.

4/2013 - pages 123 - 129download PDF file

Biogas upgrading to biomethane

Veronika Vrbová, Karel Ciahotný, Alice Vagenknechtová

Biogas produced by methane fermentation of organic matter can be considered as a mixture of methane and carbon dioxide and it contains also other minor compounds, such as water vapor, sulfur in the form of hydrogen sulfide, ammonia, siloxanes, oxygen and halogen compounds. These substances may have negative effect on the upgrading process of biogas to biomethane. The adsorption is the one of the most widely used method for the removal of undesirable substances. This article is focused mainly on the removal of carbon dioxide from biogas, where its concentration is varyingfrom 25 up to 45 % vol. Separation of carbon dioxide was measured under laboratory conditions using model gas mixture containing 35 % vol. CO2 and 65 % vol. CH4. Consequently, the adsorption capacities for CO2 at selected adsorbents were measured using real biogas produced on the Waste Water treatment plant in Prague Bubeneč.

4/2013 - pages 130 - 135download PDF file

Testing of structural materials for high temperature gas cooled reactors

Jan Berka

High temperature gas cooled reactors belong to a group called Generation IV Nuclear Reactors. Research organizations and industrial companies from the Czech Republic participate in research projects aimed at these reactors. The degradation of high temperature steels in impure helium at 750°C was tested. The changes of mechanical properties and composition and thickness of corrosion layers were tested after their exposure.

4/2013 - pages 136 - 141download PDF file

Oxidation Stability of Industrial Oils by PetroOxy Tester

Nadia Ladyka
The article deals with monitoring of the oxidative stability of turbine and other industrial oils during their operation in industrial facilities. The possibility of replacing of commonly used oxidation test RPVOT by another test was verified. PetroOxy tester should be a suitable choice due to its simplicity and compact design. Oxidation conditions were selected and tested with as well as without oxidation catalyst. Temperature of 190 °C is needed for non-catalytic test, and temperature of 160 °C was found satisfactory for catalytic test. Such a temperature is very close to the temperature of the standard RPVOT test. Utilization of PetroOxy tester for industrial oils taken from operating turbines was not too reliable as their oxidation stability obtained did not correspond to the ones obtained by the standard RPVOT test. For new oils, the PetroOxy tester was, however, found satisfactory as oxidative stabilities of oils measured by PetroOxy and RPVOT corresponded well.
4/2013 - pages 142 - 145download PDF file

Pyrolysis of brown coal with high content of volatile compounds

Lenka Jílková, Karel Ciahotný, Radek Černý, Jaroslav Kusý, Josef Valeš
The brown coal pyrolysis was estimated on pilot unit at 650 °C to produce liquid product (organic and water parts). The mass balance of pyrolysis products and analysis of gas composition and liquids composition were carried out. The mass balance showed that the highest yield had coke (43 % wt.). The pyrolysis gas contained mostly methan, hydrogen and carbon oxides. The organic part was separated out of the liquid product by sedimentation. Water part contained mostly oxygen organic compounds like phenols and carboxylic acids. Organic part contained phenols and hydrocarbons (ali-phatic and aromatic hydrocarbons).
The content of oxygen in organic part of liquid pyrolysis product was rather high and therefore the subsequent treatment of this product is necessary to produce liquid fuels
4/2013 - pages 146 - 151download PDF file

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