Автор: Adrián Banski
- ENERGY CHARACTERISTICS OF BIOFUELS – WOOD CHIPS FROM DENDROMASS OF PLANTATION GROWN BLACK LOCUST
In the present paper, energetic properties of wood chips of the species Robinia pseudoacacia (clones Ambigua, Debrecenyi 2, Göri, Matyasi, Nyirsegi, Rozaszin, Zalyi) ere determined, relative humidity of chips during a harvest, bulk density, namely the share of bark in chips, chemical composition of combustibles of chips, ash content in dry mass of biofuel, and lower heating value. Green wood chips made of dendromass from plantations consist of juvenile wood and juvenile bark. The share of juvenile bark in green wood chips of the analyzed clones of Robinia pseudoacacia is XB = 22.97 ± 1.95 %.
The nitrogen content in green wood chips made of Robinia pseudoacacia trees grown on plantation is 8 times higher than the nitrogen content in the combustibles of fuelwood of broad-leaved tree species, which has negative impact on the production of emissions – concentration of nitrogen oxides NOx in combustion products. The share of inorganic substances determined by the form of ash content Ad = 1.73 % puts the analyzed biofuel into the category of low-ash fuels. The lower heating value of green wood chips of the individual Robinia pseudoacacia clones analyzed in dry state is Qn = 18.0 MJ.kg-1.
Ключови думи: bio-fuel, energy chips, Robinia pseudoacacia, humidity, bulk density, share of bark combustibles, ash, lower heating value
- INFLUENCE OF THE TEMPERATURE COMBUSTION OF FUEL-WOOD TO CONTENT ASH
In this contribution, there are presented the results of experiments determining the influence of combustion temperature of fuel-wood on the production of ash. They confirm current knowledge about the low production of ash from wood, and specify the functional dependences between the influence of temperature at intervals of t = 500°C – 1000 °C on the production of ash from the wood of tree species: Norway spruce, White birch, European beech, English oak and Black locust.
The functional dependences of ash production on the combustion temperatures are instrumental for objectification of information about ash production from energy facilitiesfor energy, environmental, and ecological analyses and balances.
The proportion of ash from fuel-wood can be done according to standard ISO 1171:2003, or standard EN14775:2010. These standards differ in the temperature of combustion of the fuel wood sample. ISO 1171:2003 burns fuel at t = 815 °C while EN14775:2010 at t = 550 °C. Disregarding the aforementioned facts about the dependence of production of ash on the combustion temperature causes errors. By interchanging the norms ISO1171:2003 with EN14775:2010, the balances from combustion of spruce wood generate a relative error of 44.58%. The balances from combustion of wood of black locust generate a relative error of 19.10%.
Ключови думи: fuel, wood, combustion, temperature, ash
- WOOD COLOUR MODIFICATION OF FRAXINUS EXCELSIOR L. DURING THE PROCESS OF THERMAL TREATMENT WITH SATURATED WATER STEAM
The aim of the paper is to determine the colour of European ash wood (Fraxinus excelsiorL.) in the CIE-L*a*b* colour space during the thermal treatment with saturated water steam at the temperature of t = 137.5 ± 2.5 °C for the time of τ = 7.5 hours. The colour of European ash wood changes from white with a yellow hue to brown during the process of colour modification. Mentioned hue of thermally modified wood is described with the coordinates of CIE-L*a*b*colour space: L* 65.6 ± 1.4; a* = 10.8 ± 0.5; b* = 21.7 ± 0.9. Irreversible colour change of the European ash wood resulting from the process of thermal modification with saturated water steam widen the possibility for its use in the field of construction and carpentry, design as well as in the field of art.
Ключови думи: wood, European ash (Fraxinus excelsiorL.), the CIE-L*a*b*colour space, thermaltreatment, saturated water steam
- INFLUENCE OF UV RADIATION ON COLOR STABILITY OF NATURAL AND THERMALLY TREATED MAPLE WOOD WITH SATURATED WATER STEAM
The aim of this paper is to present the results of color change on the surface of natural maple wood and thermally treated maple wood with saturated water steam after UV irradiation in Xenotest 450 – simulation of natural wood aging process. Thermally untreated maple wood is white to light white-gray-yellow in color with coordinates L* = 86.6 ± 2.5; a* = 5.3 ± 1.7; b* = 19.3 ± 2.3 in CIE L*a*b* color space. The thermally treated maple wood is brown-red in color with coordinates L* = 65.3 ± 1.4; a* = 10.8 ± 1.3; b* = 19.3 ± 1.3. The surface of samples maple wood with moisture content w = 12% was irradiated in Xenotest 450 with a xenon lamp with UV radiation of 340 nm. Irradiation of the wood surface took place in the exposure cycle A1 for 7 days. While the irradiated surface of the thermally untreated maple wood darkened and acquired a brownish-yellow hue, the brownish-red hue of the thermally treated maple wood turned paled slightly. The total color difference ∆E* caused by UV radiation of thermally untreated maple wood is ∆E* = 15.2 and thermally treated maple wood is ∆E* = 10.8. A comparison of the simulated aging of thermally treated and thermally untreated maple wood in Xenotest 450 suggests that the overall color change of thermally treated wood is 28.9 % less.
Ключови думи: mountain maple, CIE L* a* b* color space, UV radiation, wood color aging simulation