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.

3/2024

1/2009

Electrochemical corrosion tests in liquid bio-fuels

The possibility of application of electrochemical techniques for corrosion studies in biofuels was tested. Electrochemical measurements were performed in environments of a broad range of electric properties - from highly resistive and low polar bio-diesel and petrol fuels to ethanol-petrol blends (E10, E60, E85) and ethanolic fuel (E100). Two types of experimental cell design were developed - tubular and planar. Experimental data obtained confirmed applicability of impedance spectroscopy measurements to bio-fuels. In all cases electric characteristics (resistivity and permittivity) of bio-fuels were obtained. Corrosion parameters were obtainable for higher polarity environments (ethanolic fuels and ethanol-petrol blends with higher content of ethanol).

Development of brown coal mining in the Czech Republic

There are two relevant features in the Czech Republic that are of a great importance for the whole Czech brown industry. The first one is the availability of energy resources. In the Czech Republic there are no or negligible crude oil resources, we also don’t have any natural gas deposits as well as any important nuclear fuel resources. In fact, the Czech Republic is fully dependent on the import of these resources. Thus, the only important domestic energy resource is the coal. The second relevant feature is the environmental and local limits of mining. The Czech Government set these limits by three Government’s resolutions in 1991. Beyond these limits the mining is not permissible. The Czech Government passed these resolutions as a quick measure to improve badly damaged environment at that time. However, now these limits prevent the opening of new prospective localities, and, which is now under a big public discussion, the limits are unfavourably reflected in the life of the giant surface mines, which holds the largest brown coal deposits in the Czech Republic.

Bio-Diesel – Perspectives of Production and Consumption in the Czech Republic

The quantities of biocomponents necessary for Diesel production in the Czech Republic is calculated based on reviewed Air Act 180/2007 a EU Directive 2009/28/ES for the period 2009-2020. Consumption of biocomponents will increase from 189 kt (in 2009) to 438 kt (in 2020). The need of the Czech production could be covered from the domestic capacities and conditions for cultivation of rape seeds up-to the year 2018. The 2nd generation of biofuels needs to be implemented after 2018, as well as hydrogen or electric power from renewable sources. Increased use of biocomeponents could be achieved by increased content in the Diesel and also via high-concentrated Bio-Diesel (FAME content 30% vol.). It is shown that RME produced in the plant with capacity 100 kt/year installed in the Czech Republic achieves savings of Green-House-Gases 45,7% comparing to 35% requested. Energy intensity of RME production reaches 0,37 GJ/GJ which means that consumed energy has 2,7 times return. In case of use of rape straw energy consumption further decreases to 0,26 GJ/GJ.

Biotope assessment and evaluation as a method to quantify the external costs related to surface bro

Surface brown coal mining like many other fields of industry can be characterized by a wide range of adverse effects on the environment. There are several environmental fees paid by mining companies that were implemented into the Czech legislation in order to compensate the environmental damage caused by mining activities. This paper describes the methodology of the Hessian method and its application to a selected open-cast mine in the North-western Bohemia. It has been approved that the method is appropriate for evaluation of environmental damage caused by large-scale impacts on landscape. However, it has also been concluded that the calculated amount of environmental damage caused by surface mining corresponds to the amount of environmental fees currently paid by mining companies.

Proximate analysis of fuels by thermogravimetry

Proximate analysis results obtained by both standard methods and TGA thermogravimetry were compared for coals, woody pellets, sewage sludge and fermented wastes from Portugal region. Water contents analyzed by TGA moisture method and CSN standard method at the temperatures of 130 °C and 105 °C showed that the CSN is more suitable for unknown, thermally sensitive and hardly disintegrable fuels. The TGA method can be recommended for well-known fuels provided that analytical sample is prepared by cold-milling. Compositional analysis up to the temperature of 900 °C on pre-dried analytical samples showed that the TGA results of volatile compounds V, fixed carbon FC and ash content A are in agreement to ISO result provided that fuels with higher fixed carbon content are used. The TGA method can be adapted and optimized to minimize differences between ash determination and ash content by ISO method. Future development will overcome experimental difficulties with few difficult samples such as sewage sludge and fermented waste.

Allothermal Fluidized Bed Biomass Gasification

Biomass has the potential to become the key renewable source of electrical energy in the Czech Republic. Presently, the gasification in conjunction with gas motor is the most viable technology for the transformation of ligno-cellulosic biomass to electrical energy. A wood chips fuel was gasified in the experimental atmospheric fluidized bed reactor. The influence of reactor temperature and material of the fluidized bed on gas composition and gas yield was studied. Calcite as a material of the fluidized bed was found to have positive catalytic effect on gas composition and gas yield. Optimum temperature for the in-bed use of calcite was proposed to be around 830 °C.