3/2013
Comparison of hydrogen quality from different production technologies
This paper is focused on conventional methods of hydrogen production using the reforming of fossil fuels. We also discussed the alternative methods of production which are still in research. Nowadays, the steam reforming is used as a dominant source of hydrogen. The reason is the high ratio of CO in gas inlet from the initial steps of high–temperature conversion. Most of the technology processes require desulfurization which causes higher price of the final product. Fossil fuels transformed by steam reforming produce 70-80 vol. % of Hydrogen in contrast to partial oxidation that produces only 35 vol.%.
The use of Rancimat test for determination of oxidation stability of biofuels
The one of more important property of diesel fuel is oxidation stability. The purpose of this paper is to describe determination of oxidation stability by test Rancimat. According with the standard EN 14112+A1 (2010), the oxidation stability is the value of the time expressed in hours, which passes between the moment when the measurement is started and the moment when the formation of oxidation products rapidly begins to increase. The oxidation stability was measured in a 743 Rancimat apparatus. Experiments showed the influence of biodiesel blending in a decrease of diesel fuel stabil-ity and negative influence of impurity on oxidation stability of biodiesel.
Utilization of a Pressure DSC for Determination of Oxidation Stability of Biodiesel
Biodiesel is an alternative fuel for diesel engines made from renewable biological sources such as vege-table oils and animal fats. The one of more important property of biodiesel is oxidation stability. This work is focused on possibility for determination of oxidation stability of biodiesel by using a pressure DSC method.
Measuring of a discharge coefficient of orifices with irregular edges
The Effect of potassium carbonate on Thermal Oxidation of Cokes and Carbonaceous Materials
The effect of K2CO3 on thermal oxidation of the blast furnace cokes and carbonaceous materials in the air was investigated by means of thermal analysis. The results obtained from the thermal analysis showed that coke contains two carbonaceous structures. The addition of K2CO3 affected mainly oxidation of a less ordered structure while the second stage oxidation went without changes. With increasing concentration of an additive, a decrease of both the characteristic temperatures and the values of activation energy occurred together with enhancement of reaction heat. The catalytic effect of potash on the oxidation of materials with variously ordered carbonaceous structure grows with no order of carbonaceous matter. In all cases (except graphite) the addition of potash caused a decrease of activation energies.
The use of E85 in fuel systems of common spark ignition engines
In case of cars equipped with spark ignition en-gines, the increase if biofuel consumption according to EU directives can be ensured either with bulk increase in ethanol concentration in petrol, or with broader use of high-percentage ethanol blends, e.g. E85. However, it requires larger expansion of flex-fuel vehicles fleet, or the use of engine retrofit systems enabling the use of E85 in conventional SI engines. The most important role of such systems is to increase fuel injection time according to different E85 properties. The paper sum-marises differences in composition and properties of petrol and E85, and gives theoretical and experimental background for calculation of relative injection time increment.