http___fulir.irb.hr_2234_.xml
http___fulir.irb.hr_1739__1.xml
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Krajcar Bronić, Ines; Barešić, Jadranka; Horvatinčić, Nada (2015) Application of 14C method for biogenic component determination in waste and liquid fuels. In: Krajcar Bronić, Ines; Horvatinčić, Nada; Obelić, Bogomil, (eds.) Book of Abstracts - ESIR Isotope Workshop XIII. Zagreb, Ruđer Bošković Institute, p. 103 . Abstract Increase of CO2 concentration in the atmosphere during 20th century is a consequence of intensive use of fossil fuels. The increase of CO2 concentration can be slowed down by the use of biogenic materials for energy production and/or transport. One of the method for determination of the fraction of the biogenic component in any type of fuel or waste is the 14C method, which is based on different content of 14C in biogenic (reflects the modern atmospheric 14C activity) and in fossil component (no 14C present). The method can be applied to various types of fuels used in waste-to-energy plants (such as solid communal waste, used car tyres), to liquid fuels, even to the CO2 produced by combustion of various fuels. Any measuring technique used in 14C dating laboratories could be used. Here we present comparison of characteristics (precision, complexity, price) of various techniques (sample preparation and measurement) for biogenic fraction determination by the 14C method. A case of liquid fuels will be specially discussed. According to the EU Directive 2009/28/EC all (liquid) fuels have to contain at least 10 % of bio-fuel, i.e., blend of biogenic origin, by 2020. A technique of direct measurement in liquid scintillation counters of the 14C content in liquid fuel is simple and fast but has a main disadvantage: different liquid colours cause different quenching and thus changes in the measurement efficiency. We propose a new data evaluation technique that uses liquids of different colours to construct calibration curves for modern and background samples [1]. The technique depends neither on the fossil matrix or the biogenic additive type. Lowest detectable biogenic fraction is 0.5 %. [1] Krajcar Bronić I, Barešić J, Horvatinčić N, Krištof R, Kožar-Logar J. In: Proc. 10th symposium of the Croatian Radiation Protection Association, Šibenik, 15 – 17 April 2015. CRPA, Zagreb, 2015.
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Krajcar Bronić, Ines; Barešić, Jadranka; Horvatinčić, Nada; Krištof, Romana; Kožar-Logar, Jasmina (2015) New technique of determination of biogenic fraction in liquid fuels by the 14C method. In: Petrinec, Branko; Bituh, Tomislav; Milić, Mirta; Kopjar, Nevenka, (eds.) Zbornik radova Desetog simpozija Hrvatskog društva za zaštitu od zračenja. Zagreb, Hrvatsko društvo za zaštitu od zračenja, pp. 360-365 . Abstract Povišenje koncentracije CO2 u atmosferi tijekom 20. stoljeća posljedica je intenzivnog korištenja fosilnih goriva. Smanjenje emisije CO2 nastalog izgaranjem fosilnih goriva proizvodnjom energije iz biogenih materijala (biogoriva) danas se stimulira i poreznom politikom pa se javlja potreba kontrole proizvođača i distributera goriva primjenom pouzdane metode određivanja udjela biogene komponente u gorivima. Jedna od metoda za određivanje udjela biogene komponente u smjesi fosilnog i biogoriva je 14C metoda, koja se zasniva na različitoj koncentraciji izotopa 14C u pojedinim komponentama smjese: biogoriva odražavaju 14C aktivnost suvremene atmosfere, dok fosilna goriva ne sadrže 14C. Za tekuća goriva moguće je primijeniti tehniku direktnog mjerenja u tekućinskom scintilacijskom brojaču (LSC) uz dodatak odgovarajućeg scintilatora. U ovom radu ćemo prikazati novu tehniku direktnog mjerenja koja koristi karakteristike gašenja zbog boje za kalibraciju brojača. Određivanje udjela biogene komponente u tekućim gorivima moguće je direktnim mjerenjem sadržaja 14C tekućinskim scintilacijskim brojačem. Tehnika obrade rezultata razvijena na IRB daje rezultate usporedive s drugačijom tehnikom korištenom na IJS. Donja granica detekcije je oko 0, 5 % biogene komponente, a tehnika se može primijeniti na sve vrste goriva bez obzira na fosilnu matricu i vrstu biogenog aditiva.