http___fulir.irb.hr_2112_.xml
http___fulir.irb.hr_1739__1.xml
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Krajcar Bronić, Ines; Barešić, Jadranka; Horvatinčić, Nada (2015) Determination of biogenic component in waste and liquid fuels by the 14C method. In: ISRP13 - The 13th International Symposium on Radiation Physics. Beijing, China, IRPS - International Radiation Physics Society, p. 40 . Abstract Intensive use of fossil fuels for energy production and transport during 20th century caused an increase of CO2 concentration in the atmosphere. 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 and in fossil component: while the biogenic component reflects the modern atmospheric 14C activity, no 14C is present in fossil fuels. The 14C method is the most reliable method of determination of the biogenic fraction in fuels and it can be applied to various types of fuels used, such as solid communal waste, used car tyres, liquid fuels, even to the CO2 produced by combustion of various fuels. Any measuring technique used in 14C laboratories could be used. Here we present comparison of characteristics (precision, complexity, and price) of various techniques 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 of the 14C content in liquid fuel is simple and fast but has a main disadvantage: different liquid colours cause different quenching properties and changes in the measurement efficiency. Various methods have been suggested to overcome this problem (e.g., decolourization, separate quenching curves for various combinations of the fossil matrix and biogenic blends). We propose here a new technique that uses liquids of different colours to construct modern and background calibration curves. The technique depends neither on the fossil matrix or the biogenic additive type. Lowest detectable biogenic fraction is 0.5 %.
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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.