Tag Archives: elemental analysis

276-285 B. Tamelová, J. Malaťák and J. Velebil
Energy valorisation of citrus peel waste by torrefaction treatment
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Energy valorisation of citrus peel waste by torrefaction treatment

B. Tamelová*, J. Malaťák and J. Velebil

Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamycka 129, CZ165 21 Prague, Czech Republic
*Correspondence: tamelova@tf.czu.cz

Abstract:

The article deals with the issue of processing and utilization of citrus peel, which often ends unused with other biodegradable waste. The research is concerned with the energy potential of this raw material and its torrefaction conversion. The tested materials were orange peel (Citrus sinensis Osbeck cv ‘Valencia’, Citrus sinensis Osbeck cv ‘Murcia’) and grapefruit peel (Citrus paradise ‘Ruby red’). Samples of dried materials underwent torrefaction treatment at 225 °C, 250 °C and 275 °C for 30 minutes. Samples before and after torrefaction were analysed for proximate and elemental composition and for calorific value. Consequently, stoichiometric combustion analyses were done. The torrefaction was performed in a LECO TGA 701 thermogravimetric analyzer under nitrogen atmosphere. The results of proximate and elemental analysis showed positive influence of torrefaction on the samples. The highest net calorific value for orange peel is 24.97 MJ kg-1 at the temperature of 275 °C. The greatest differences in net calorific values are between 225 °C and 250 °C where the increase is almost 3 MJ kg-1. Subsequently, the increase between the 250 °C and 275 °C torrefaction temperatures is 1 MJ kg-1. Weight loss at respective torrefaction temperatures showed similar time-dependent curves for all samples. Stoichiometric combustion analysis shows slight differences between original samples, but great differences after torrefaction processing. Stoichiometric combustion parameters also change proportionately with increasing temperature of torrefication. The resulting comnbustion balance figures show significantly lower need for mass of fuel in the case of the torrefied material for a given heat output thanks to the net calorific value being nearly doubled.

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157-166 J. Malaťák, J. Bradna, J. Velebil, A. Gendek and T. Ivanova
Evaluation of dried compost for energy use via co-combustion with wood
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Evaluation of dried compost for energy use via co-combustion with wood

J. Malaťák¹*, J. Bradna¹, J. Velebil¹, A. Gendek² and T. Ivanova³

¹Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ165 21 Prague, Czech Republic
²Warsaw University of Life Sciences, Department of Agricultural and Forest Machinery, Faculty of Production Engineering, Nowoursynowska 166, PL02-787 Warsaw, Poland
³Czech University of Life Sciences, Faculty of Tropical AgriSciences, Department of Sustainable Technologies, Kamýcká 129, CZ165 21 Prague, Czech Republic
*Correspondence: malatak@tf.czu.cz

Abstract:

There is still a question of utilization of compost of unsatisfactory quality. This article deals with energy utilization of untreated compost. The energy utilization of raw compost as a fuel is not directly possible without further processing. Separation might be necessary due to large amount of mineral content (soils and other inert substances).
This article is focused on the analysis of the basic fuel characteristics of compost. Proximate and elemental analyses were performed and stoichiometric combustion was calculated. Finally, the sample was co-burned with wood biomass in a fixed grate combustion device and the gaseous emissions were determined in dependence on the amount of combustion air supplied. The emissions were expressed in graphs against excess air coefficient and flue gas temperature.
Elemental analysis of the compost sample shows high percentage of ash up to 61.70% wt. on dry basis causing low average calorific value of 8.51 MJ kg-1 on dry basis. For combustion tests, the heating value was increased by addition of wood chips to reach an average calorific value of the mixture to 13.4 MJ kg-1. The determined stoichiometric parameters can help in optimization of diffusion controlled combustion of composts or similar materials. In combustion of the mixture of compost and wood biomass an optimum of emission parameters was found not exceeding the emission limits. Measured emission concentrations show the possibility of optimizing the combustion processes and temperatures while lowering CO emissions via the regulation of combustion air.

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1257-1265 J. Bradna, J. Malaťák and D. Hájek
The properties of wheat straw combustion and use of fly ash as a soil amendment
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The properties of wheat straw combustion and use of fly ash as a soil amendment

J. Bradna, J. Malaťák* and D. Hájek

Czech University of Life Sciences Prague, Faculty of Engineering, Department of
Technological Equipment of Buildings, Kamýcká 129, CZ165 21 Prague, Czech Republic
*Correspondence: malatak@tf.czu.cz

Abstract:

Agriculture is one of possible producers of by-products suitable for energy purposes,

such as rapeseed and wheat straw. But on the other hand, not only thanks to the support of energy
from biomass grown specifically for this purpose, arable land is exposed to intense cultivation of
wide-row crops indirectly supporting soil erosion and nutrient elution. The issue of recycling ash
from biomass combustion on agricultural and forest land is very important to resolve. Experience
with this problem is found in countries in Northern Europe such as Finland or Sweden, as well as
in North America. Due to ash characteristics, it is considered a valuable soil component and a
potential replacement for conventional fertilizers.
Elemental analyses of samples from wheat straw pellets were followed by combustion and
emission measurements. The effects of temperature and volume of air in the combustion of wheat
straw was analysed, focusing on emission concentrations and the ash content. Effect of excess air
coefficient on the composition of end products after combustion was assessed in three modes
(small, optimum and high coefficient of excess air). During the measurements, the excess air
coefficient ranged between the values from 3.95 to 14.89. The average net calorific value of the
wheat straw samples was 15.55 MJ kg-1 in the original state. Mineral composition analysis of
solid combustion products, necessary for using these residues as a fertilizer or soil component,
was performed as well.

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