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2018, Vol. 16, No. 2

Selle kollektsiooni püsiv URIhttp://hdl.handle.net/10492/5375

Sirvi

Sirvi 2018, Vol. 16, No. 2 Märksõna "ash" järgi

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  • Pisipilt
    Kirje
    Chemical composition of agromass ash and its influence on ash melting characteristics
    (2018) Čepauskienė, D.; Pedišius, N.; Milčius, D.
    The increasing demand for biofuels leads to a growing need for agromass, such as herbaceous plants and agricultural waste. However, agromass contains high quanitites of alkali metals, mainly potassium and sodium, which limits agromass usage in thermoconversion processes. Alkali metals react with other ash forming elements which leads to ash related problems such as agglomeration, fouling and slagging during agromass burning. In this study, chemical composition and melting behaviour of ashes form ed at 550 ° C are investigated. Three herbaceous plants (reed canary grass, hemp, orchard grass), four types of agricultural waste (straws of rye, wheat, buckwheat and canola) and two types of woody biomass (birch, spruce) are selected. Ash melting behaviou r, composition and bulk structure are determined using a high temperature furnace with a video camera, inductively coupled plasma atomic emission – spectrometry and X – ray diffraction technique, respectively . Ash melting behaviour of selected agromass types s hows that the hemp ash has the highest shrinkage starting temperature which reaches 1 , 079 °C. This is due to the high content of calcium and low content of potassium and sodium in hemp ash. T hree main components calcium carbonate, potassium sulfate and pot assium chloride have been identified in ashes after agromass and woody biomass are heat – treated at temperature of 550 °C.
  • Pisipilt
    Kirje
    Combustible in selected biofuels
    (2018) Vitázek, I.; Tulík, J.; Klúčik, J.
    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 cons isted 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, cher ry, 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.