Tag Archives: biomass

xxx D. Urbancl, J. Krope and D. Goričanec
Torrefaction – the process for biofuels production by using different biomasses
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Torrefaction – the process for biofuels production by using different biomasses

D. Urbancl*, J. Krope and D. Goričanec

University of Maribor, Faculty of Chemistry and Chemical Engineering, Smetanova street 17, SI2000 Maribor, Slovenia
*Correspondence: danijela.urbancl@um.si

Abstract:

Torrefaction process is a mild pyrolysis, where biomass material is converted into solid fuel with higher heating value. The results of torrefaction at different temperatures in a range from 220 to 400 °C for three varied materials, oak wood, mixed wood and dehydrated, granulated sewage sludge are presented. The torrefaction process started with warm up stage, which took place for 30 minutes, after that sample was torrefied for 2 hours at constant temperature. The process continued with cool down stage. The energy demands were covered by electric power, while the flue gasses were not integrated in the process. The influence of the operating temperatures are analysed in order to determine optimal operation parameters to get the torrefied biomass with highest calorific value. Furthermore, the optimal operation time according to the largest increase in calorific value for each material is evaluated. The results of calorific value, mass drop and chemical compositions such as elemental analyses are also presented. Results show that heating values increase with raising temperature for both wood samples. The heating values for sewage sludge increases to approximately 320 °C, after that temperature are unchangeable. Torrefied oak wood samples were more fragile at higher temperatures in comparison to raw or torrefied oak wood samples at lower temperatures. At torrefied sewage sludge samples the changes in fragility are not detected due to pre-prepared granulates of sludge.

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xxx M. Toom, L. Talgre, P. Pechter, L. Narits, S. Tamm and E. Lauringson
The effect of sowing date on cover crop biomass and nitrogen accumulation
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The effect of sowing date on cover crop biomass and nitrogen accumulation

M. Toom¹²*, L. Talgre², P. Pechter¹, L. Narits¹, S. Tamm¹ and E. Lauringson²

¹Estonian Crop Research Institute, J. Aamisepa 1, EE48309 Jõgeva, Estonia
²Estonian University of Life Sciences, Kreutzwaldi 1, EE51014 Tartu, Estonia
*Correspondence: merili.toom@etki.ee

Abstract:

Cover crops are important tools for reducing nitrogen (N) leaching from the soil and improving the nutrition of cash crops. In northern regions with short autumns it is important to maximise the growing season of cover crops to achieve sufficient biomass and N accumulation. The objective of the study was to evaluate the biomass and N accumulation of cover crops at different sowing dates in August.
Field experiment at Estonian Crop Research Institute was conducted in 2017 and 2018 with white mustard (Sinapis alba L.), phacelia (Phacelia tanacetifolia Benth), buckwheat (Fagopyrum esculentum Moench), berseem clover (Trifolium alexandrinum L.), field pea (Pisum sativum L.) and faba bean (Vicia faba L.). Cover crops were sown on August 3, 8, 14 and 18 in 2017 and August 3, 8, 13, 17 and 23 in 2018.
The two year experiment showed that biomass and N accumulation of cover crops were reduced with delayed sowings, but the reduction mainly depended on cover crop species.
White mustard, field pea and faba bean accumulated significantly higher amount of biomass and N than phacelia, buckwheat and berseem clover at all sowing dates in both years. Because of a rapid decrease in biomass, the optimum sowing time for phacelia and buckwheat should not be later than middle of August. In both year berseem clover produced the modest amount of biomass and therefore more suited as spring sown cover crop in Estonian conditions.

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862–871 B. Tamelová, J. Malaťák and J. Velebil
Hydrothermal carbonization and torrefaction of cabbage waste
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Hydrothermal carbonization and torrefaction of cabbage waste

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

Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZCZ165 21 Prague, Czech Republic
*Correspondence: tamelova@tf.czu.cz

Abstract:

In recent years, waste biomass has been increasingly becoming an energy source. The utilization of biomass includes a number of potential treatments: thermochemical, physicochemical and biochemical. In the food industry, significant amounts of biodegradable wastes are produced which have to be quickly treated to not pose an environmental problem. In this work cabbage waste (Brassica oleracea var. capitata) was treated by hydrothermal carbonization and torrefaction.
Hydrothermal carbonization experiments were carried out in a pressure reactor vessel Berghof BR-300 (inner volume 400 mL, temperature regulation by Berghof BTC 3000). The carbonization took place at target temperatures 180 °C and 225 °C. Torrefaction tests were carried out in a thermogravimetric programmable oven LECO TGA701 under nitrogen atmosphere at temperatures 225 °C, 250 °C and 275 °C. The residence time was 30 min for both processes. Proximate and elemental composition, as well as calorific value was analysed in all samples. To express the influence of the treatments on combustion behaviour, stoichiometric combustion calculations were performed.
The analyses show a positive effect of both torrefaction and hydrothermal carbonization on fuel properties in the samples. Most obvious is the reduction in oxygen content which depends on the process temperature. After hydrothermal carbonization at 225 °C the oxygen content was lowered by 46.7%. The net calorific value increased proportionally with temperature in both processes. After hydrothermal carbonization at 225 °C the net calorific value increased on average by 3 MJ kg-1 to 20.89 MJ kg-1. Both tested processes significantly increased the fuel value of this biodegradable waste.

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474-482 M. Križan, K. Krištof, M. Angelovič, J. Jobbágy and O. Urbanovičová
Energy potential of densified biomass from maize straw in form of pellets and briquettes
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Energy potential of densified biomass from maize straw in form of pellets and briquettes

M. Križan, K. Krištof*, M. Angelovič, J. Jobbágy and O. Urbanovičová

University of Agriculture in Nitra, Faculty of Engineering, Department of Machines and Production Biosystems, Tr. A. Hlinku 2, SK94976 Nitra, Slovakia
*Correspondence: koloman.kristof@uniag.sk

Abstract:

The aim of the study was the evaluation and comparison of energy potential of briquettes and pellets produced from the maize straw and woody biomass based on various diameters of pellets. By experimental measurements a calorific value and ash content was observed. Calorific value was measured by laboratory calorimeter IKA C 6000 (IKA® Works, Inc., USA) and laboratory combustion chamber Lindberg/Blue M (Thermo Fisher Scientific, Inc., USA). Individual calorific values and ash content was observed and subsequently confronted to obtain differences with replication. The analysis showed that calorific value of pellets with diameter 6 mm ranged from 16.99 MJ kg-1 to 17.80 MJ kg-1. Calorific value of pellets with 8 mm diameter ranged from 16.63 MJ kg-1 to 17.20 MJ kg-1. However, compared calorific value of briquettes ranged from 14.99 MJ kg-1 to 15.66 MJ kg-1. Further analysis showed that ash content of samples varied as well and it’s even affected by diameter of pellets. While ash content of pellets with diameter 6 mm was observed as 4.9% of total volume in case of pellets with 8 mm it was observed at value 5.5%. Briquettes produced from maize straw have ash content at value 5.4%. In contrary, ash content of woody biomass was significantly higher, 11% of volume, specifically. At the basis of observed parameters it can be concluded that maize straw densified in form of briquettes and pellets have a great energy potential which is comparable and competitive with currently used materials for production of briquettes and pellets.

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593-603 I. Vitázek, J. Tulík and J. Klúčik
Combustible in selected biofuels
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Combustible in selected biofuels

I. Vitázek*, J. Tulík and J. Klúčik

Slovak University of Agriculture in Nitra, Faculty of Engineering, Department of Transport and Handling, Tr.A. Hlinku 2, SK949 76 Nitra, Slovak Republic
*Correspondence: ivan.vitazek@uniag.sk

Abstract:

The aim of the research was to determine the moisture, combustible and ash content in selected biofuels, in dependence on temperature by the means of gravimetric method. For this purpose, the furnace Nabertherm L9/11/SW/P330 was used. Analyzed samples consisted of crushed biomass which is used in small heat sources (e.g. spruce wood, cherry wood, apple wood, black locust wood) with bark and without additives. Biomass for larger heat sources (woodchips cuttings from coniferous trees), sawdust mix (plum, cherry, walnut, apricot, apple) and pellets (90% spruce and 10% fir) were also analyzed. The results are processed graphically and enable to characterize the tested fuels. The highest content of combustible was found in spruce wood sample without bark (99.889%), the lowest content of combustible indicated cuttings from coniferous trees (88.402%). Gravimetric experiments were supplemented by DSC measurement of selected samples on calorimeter Toledo DSC822e. The graphic courses of reactions are provided up to 500 °C.

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22-40 F. da Borso, C. Di Marzo, F. Zuliani, F. Danuso and M. Baldini
Harvest time and ensilage suitability of giant reed and miscanthus for bio-methane production and characterization of digestate for agronomic use
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Harvest time and ensilage suitability of giant reed and miscanthus for bio-methane production and characterization of digestate for agronomic use

F. da Borso, C. Di Marzo, F. Zuliani, F. Danuso and M. Baldini*

Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, Via delle Scienze, 206, IT33100 Udine, Italy
*Correspondence: mario.baldini@uniud.it

Abstract:

In many countries, biogas plants are mainly fed by livestock slurry and dedicated crops, including maize, which still represents one of the main energy crops utilized. Many concerns are now arising on environmental impact due to the high water consumption, chemical fertilizer and pesticide requirements and on adverse effect of maize as energy crop on the price of food and feed commodities. For these reasons two perennial crops, in particular miscanthus (Miscanthus x giganteus) and giant reed (Arundo donax L.), were cultivated at very low input and evaluated for their bio-methane yield at different harvest times and ensilage suitability, in a north-eastern area of Italy. Moreover, considering the agronomic use of the obtained digestate as fertilizer, this has been characterized by the content of heavy metals. Both multi-annual crops have proved highly productive in biomass especially with a harvest time in autumn, at which a satisfactory completion of the silage process without additives was observed. Conversely, bio-methane yield per hectare were not satisfactory with respect to the reference crops such as maize. The low BMP attained showed the main bottleneck of the methanisation of ensiled giant-reed and miscanthus, which is represented by fiber composition with high degree of lignification. The simulation use of digestate obtained as fertilizer in vulnerable areas, could lead to slightly exceed the levels allowed by the legislation of some European countries with regard of heavy metals as Cu, Zn and Cd.

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1956–1970 M.A. Luna-delRisco,, K. Orupõld, I. Diaz-Forero and M. González-Palacio
Influence of chemical composition on the biochemical methane potential of agro-industrial substrates from Estonia
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Influence of chemical composition on the biochemical methane potential of agro-industrial substrates from Estonia

M.A. Luna-delRisco¹,*, K. Orupõld², I. Diaz-Forero³ and M. González-Palacio¹

¹ Universidad de Medellin, Faculty of Engineering, Energy Engineering,
Carrera 87 # 30 – 65, P.O. 050026 Medellin, Colombia
² Estonian University of Life Sciences, Faculty of Agricultural and Environmental
Sciences, Kreutzwaldi 1, EE51014 Tartu, Estonia
³ Servicio Nacional de Aprendizaje – SENA, Center for Design and Manufacture of
Leather, BIOMATIC Research Group, Calle 63 # 58B – 03, P.O. 055413 Itagüí,
Colombia
*Correspondence: mluna@udem.edu.co

Abstract:

Batch trials were carried out to evaluate the Biochemical Methane Potential (BMP) of 61 different substrates collected from agricultural farms and industrial sites in Estonia. Tests were performed in 500 mL plasma bottles at 36°C. The highest methane yield from all tested substrates was obtained from unconsumed dairy products (557 ± 101 L kg-1 VS) while the lowest was obtained from animal slurries (238 L kg-1 VS ± 42). From tested energy crops, foxtail millet achieved the highest methane yield (320 L kg-1 VS). Silages from different crops presented methane yields from 296 ± 31 L CH4 kg-1 VS to 319 ± 19 L CH4 kg-1 VS. The influence of chemical composition and kinetic rate constants (k) on methane potential was analyzed. Anaerobic digestibility of selected agro-industrial substrates was markedly influenced by their organic content, i.e. total proteins and lignin concentrations. Rate constants were found to correlate negatively with hemicellulose, cellulose and lignin (p < 0.05). Results from this study suggest that an appropriate characterization of the chemical composition of the substrates is important not only for predicting BMP and the kinetics rates, but also for identifying possible inhibitors during the anaerobic digestion process. Results on the BMP and national availability of studied substrates indicate that herbal biomass and agro-industrial residues are promising substrates for biogas production in agricultural biogas facilities in Estonia.

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2226–2235 P. Zeman, V. Hönig, P. Procházka and J. Mařík
Dimethyl ether as a renewable fuel for diesel engines
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Dimethyl ether as a renewable fuel for diesel engines

P. Zeman¹, V. Hönig¹*, P. Procházka² and J. Mařík³

¹Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Department of Chemistry, Kamýcka 129, CZ16521, Prague 6, Czech Republic
²Czech University of Life Sciences Prague, Faculty of Economics and Management, Department of Economics, Kamýcka 129, CZ16521, Prague 6, Czech Republic
³Czech University of Life Sciences Prague, Faculty of Engineering, Department of Vehicles and Ground Transport, Kamýcka 129, CZ16521, Prague 6, Czech Republic
*Correspondence: honig@af.czu.cz

Abstract:

The area of automotive fuel, or fuel components, which can be produced from biomass also includes dimethyl ether, otherwise known as DME. The issue of the use of DME as a fuel is one which has been monitored until recently. Biomass can also be used as the raw material for the production of DME. DME has therefore replaced the previously-used CFCs (chlorofluorocarbons), which are now banned for their role in dangerous levels of ozone depletion. With regard to its physical properties and combustion characteristics, it is currently expected that DME will soon apply significantly as a fuel in the municipal sector and in households, and as an alternative fuel for motor vehicles with diesel engines. DME is a suitable fuel for diesel engines and can be considered as one of the most promising diesel fuel replacements. DME is a suitable fuel for diesel engines mainly due to its low self-ignition temperature and good cetane figures. It is well miscible with most organic solvents and because the polar solvent is water-immiscible. The advantage is its high levels of purity, and its being free of sulphur, nitrogen, or metals. The physical properties of DME are very similar to the physical properties of LPG. DME requires relatively complex and costly fuel accessories, but the original compression ratio of the diesel engine is maintained. A diagram of the fuel system is illustrated in the paper. The paper analyses the dependence of vapour pressure on temperature, the dependence of the density on temperature, kinematic viscosity, the flash point, the boiling point, and the solubility of water. The objective is to evaluate this interesting energy source for applications in diesel engines.

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848–858 V. Rooni, M. Raud and T. Kikas
Technical solutions used in different pretreatments of lignocellulosic biomass: a review
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Technical solutions used in different pretreatments of lignocellulosic biomass: a review

V. Rooni, M. Raud and T. Kikas*

Estonian University of Life Sciences, Institute of Technology, 56 Kreutzwaldi Str., EE 51014 Tartu, Estonia
*Correspondence: timo.kikas@emu.ee

Abstract:

Bioethanol production from lignocellulosic biomass has attracted a lot of attention as one of the most promising alternative to liquid fossil fuels. Over the last decades a lot of research has been done to find the optimal methods & devices to produce bioethanol from all kind of lignocellulosic biomass. A traditional three-step production process is used to produce bioethanol from lignocellulosic biomass – pretreatment, enzymatic hydrolysis, & fermentation. Today, the high cost of the pretreatment prevents bioethanol from competing with petrol. In this review article, the positive & negative aspects of different pretreatment methods & patented devices are investigated & analysed. Based on the analysis several options on how to lower lignocellulosic biomass pretreatment costs & how to increase the competitiveness of bioethanol are proposed.

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1674–1685 J. Maga and K. Krištof
Effect of drill machine operating speed on quality of sowing and biomass yield
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Effect of drill machine operating speed on quality of sowing and biomass yield

J. Maga and K. Krištof*

University of Agriculture in Nitra, Faculty of Engineering, Department of Machines and Production Biosystems, Tr. A. Hlinku 2, SK949 76 Nitra, Slovakia
*Correspondence: koloman.kristof@uniag.sk

Abstract:

The paper is focused on the study and evaluation of quality of the seeding of seeds and its effect on the biomass yield. The aim was to evaluate the space arrangement of the seeds by using of polygon method on one field with the repetition for different forward speeds of the drill machine. For the evaluation there were used digital photographs, which were taken during repeated measurements of the each value of the forward speed after sprouting of crop. These images have been used in order to determine the shape and size of the surface area belonging to the plant. Own software TfPolyM was used for the image analysis. The shape of the polygons belonging to the individual plants was expressed by values of the shape factor Tf. This factor characterises the suitability the shape of polygon surface related to the individual plant. By comparing of the values of the shape factors for different forward speeds of the drill machine we can determine the optimal value of the forward speed from the point of seed placement uniformity in horizontal level. During harvest of the crop there was analysed the variability of the biomass yield in relation to values of the forward speed used during seeding. The most suitable values of shape factor Tf (0.8519) was recorded for speed of drill machine set on 12 km h-1. For other tested speeds 8, 10, 15 km h-1 were recorded lower values of shape factor 0.7994, 0.8173 and 0.8449, respectively. In determination of biomass production for drill machine speed 12 km h-1 the greatest yield from 1 m2 was observed. Subsequently, for speeds 8 and 10 km h-1 was lower about 4.26% and 1.83%, respectively. For tested speeds of drill machinery 15 km h-1 and above was observed only a small descent of yields about 0.6%. Fluctuation in yields affected by working speed then demonstrates fluctuation in sowing rate. It was also observed that the working speed of sowing machinery also affect the amount of yield directly. However, in case of lowest yield of straw recorded it was observed even 20% decrease in yield of grains.

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