Tag Archives: elemental and stoichiometric analyses

725–732 D. Černý, J. Malaťák and J. Bradna
Influence of biofuel moisture content on combustion and emission characteristics of stove
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Influence of biofuel moisture content on combustion and emission characteristics of stove

D. Černý*, J. Malaťák and J. Bradna

Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ 165 21 Prague, Czech Republic
*Correspondence: david.cerny@dotacenazeleno.cz

Abstract:

 The research aim was to study the effect of moisture in solid fuel on combustion in a stove and its emissions. Analysed samples were from spruce woodchips. Four samples were prepared with different moisture contents and furthermore spruce wood was used as a reference sample. Combustion device used was a stove with a fixed fire grate. Studied parameters were ambient temperature, temperature of flue gases, coefficient of excess air, and contents of oxygen and carbon monoxide in flue gases. Laboratory measurement was performed on an analyser of flue gases whose function is based on electro-chemical converters. Measured values were first converted to a referential oxygen content in flue gases. Evaluation of these values was then made by regression analyses. The course of combustion process and its quality can be seen well in functional dependence of carbon monoxide on excess air coefficient. The area of combustion was the smallest with the least moist sample (3.2%) and increases with increasing moisture. A sample with high moisture (31.1%) was already causing the fire to gradually extinguish. Because flue gas temperature is in the same range for all samples, the overall efficiency of the stove decreases sharply with fuel moisture due to specific heat of flue gases. It has been thus confirmed that fuel moisture content has a substantial influence on combustion, especially in the chosen combustion device, which has been verified by comparison with the reference fuel.

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413-419 K. Skanderová, J. Malaťák and J. Bradna
Energy use of compost pellets for small combustion plants
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Energy use of compost pellets for small combustion plants

K. Skanderová, J. Malaťák* and J. Bradna

Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ16521 Prague, Czech Republic; *Correspondence: malatak@tf.czu.cz

Abstract:

The purpose of this paper is to explore the thermal emission characteristics of alternative fuels gained from the composting process and intended for local energy use. The first goal is to determine the basic parameters of the examined samples (elemental analysis). The thermal emission parameters of the combustion device, such as the flue gas temperature and emission concentration of carbon monoxide, carbon dioxide and nitrogen oxides in relation to the operating conditions of the combustion device with an automatic feed fuel burner furnace are also considered. Pellets from oversized chips gained from the composting process and the pelleted mixtures of compost and spruce sawdust in the ratio 1:1 were burnt in the burner furnace. The resulting values of the samples’ individual elemental analyses indicate the optimal properties for further energy utilization. The amount of excess air generated during combustion, however, is high and this is also reflected in the great loss of flue gas sensible heat. The resulting parameters further prove that the excess air coefficient (n) depends on flue gas temperature, as well as carbon dioxide, monoxide and nitrogen oxides content in the flue gas. It was concluded during the combustion tests that the pollutants monitored in the flow did not reach the limit values. The scientific hypothesis of the author confirms that the stabilized dried mixture of plant biomass and appropriate biodegradable waste is suitable for biomass combustion. The available data suggest that the use of compost for energy purposes through combustion is possible, if biodried biomass is used, i.e., special products of composting processes are used in medium-sized and large combustion devices.

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