{"id":117709,"date":"2022-10-31T07:20:00","date_gmt":"2022-10-31T06:20:00","guid":{"rendered":"https:\/\/renewable-carbon.eu\/news\/?p=117709"},"modified":"2022-10-26T14:55:28","modified_gmt":"2022-10-26T12:55:28","slug":"determining-the-biogenic-content-of-naphtha-and-other-biofuels-using-the-radiocarbon-method","status":"publish","type":"post","link":"https:\/\/renewable-carbon.eu\/news\/determining-the-biogenic-content-of-naphtha-and-other-biofuels-using-the-radiocarbon-method\/","title":{"rendered":"Determining the biogenic content of Naphtha and other biofuels using the radiocarbon method"},"content":{"rendered":"\n

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As the biofuel industry continues to gain momentum, environmental regulations and demand for biogenic fuels (biofuels) are increasing. Fuels that are produced from modern biomass are called biofuels; most biofuels available in the market today are made from plants (e.g. soy, rape, palm) or waste\u00a0\u00a0material (e.g. UCO, tallow, POME) and emit carbon neutral CO2<\/sub>. Certain plants are being cultivated specifically for biofuel production1<\/sup>\u00a0including switchgrass, soybeans, and corn in the US, sugarcane in Brazil, cassava and sorghum in China, as well as sugar beet and wheat across Europe.\u00a0<\/strong><\/p>\n\n\n\n

Many petroleum refineries are co-processing both biofuels and traditional fuels, highlighting the essential nature of quantifying the biogenic proportion of final fuel products. Furthermore, petroleum Naphtha – the intermediary product (by-product) of gasoline, diesel and renewable diesel – is another form of biogenic fuel emerging in the market. As Naphtha is commonly blended with ethanol or gasoline and also used for secondary products (e.g. plastics2,3<\/sup>), calculating the proportion of renewable vs. fossil components is important for compliance and regulatory purposes.<\/strong><\/p>\n\n\n\n

The Radiocarbon Approach<\/strong><\/h3>\n\n\n\n

The radiocarbon technique, also known as carbon-14 testing, is based on the fact that various forms of atmospheric carbon are taken up by plants and animals during their lifetime (Figure 1); both the radioactive form (14<\/sup>C) as well as the stable forms (12<\/sup>C, 13<\/sup>C). Thus, a terrestrial plant or animal is in equilibrium with its surroundings, holding a signature of the atmospheric carbon covering the years of its lifetime. Once an organism dies, it ceases to acquire carbon; instead, the radioactive carbon within its biological material will begin to decay. As time passes, the ratio of 14<\/sup>C to 12<\/sup>C gradually decreases, following a known rate. This relationship allows one to estimate time since death using an accelerator mass spectrometer (AMS), comparing the results with the radiocarbon calibration curve.<\/strong><\/p>\n\n\n\n

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Figure 1: Carbon-14 is formed in the upper atmosphere through the effect of cosmic ray neutrons upon nitrogen-14. This radioactive carbon (14<\/sup>C) is taken up by plants and animals during their lifetime, ultimately leading to\u00a014<\/sup>C decay at a predictable rate after death.\u00a0<\/figcaption><\/figure><\/div>\n\n\n\n

Thanks to nuclear physics, mass spectrometers have been fine-tuned to separate a rare isotope from an abundant neighboring mass. Today, very small fuel (0.3-0.5mL) and\/or feedstock (3-25g) samples are required for measurement, achieving high precision and low background levels – resulting in accurate measurements of biogenic vs. fossil components.<\/strong><\/p>\n\n\n\n

Regardless of the type of fuel or feedstock in question, the radiocarbon method can be utilized – most commonly using the standard ASTM D6866<\/a><\/strong>. This standard employs the radiocarbon technique to report sample components in terms of their \u201cpMC\u201d (percent modern carbon). If the material being analyzed is a mixture of present-day carbon and fossil carbon (which contains no radiocarbon), then the pMC value obtained correlates directly to the amount of modern biomass present in the sample. The value reported encompasses a 6% absolute range to conservatively account for variations in end-component radiocarbon signatures, representing maximum values. The ASTM D6866 method determines with excellent accuracy and precision the biogenic carbon fraction of fuels4<\/sup>.<\/strong><\/p>\n\n\n\n

The ASTM D6866 method is employed in a variety of regulations and certification schemes, including: <\/strong><\/p>\n\n\n\n