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Title:
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Knowledge Based Bio-based Products’ Pre-Standardization Public report on horizontal standard for bio-based carbon content determination
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Author(s):
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Published by:
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Publication date:
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ECN
Environment & Energy Engineering
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19-8-2015
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ECN report number:
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Document type:
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ECN-E--15-039
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ECN publication
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Number of pages:
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Full text:
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20
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Download PDF
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Abstract:
The term “bio-based” refers to products that are fully or partly derived from biomass. The extent to which a product is derived from biomass is characterized by its bio-based carbon content. Generally the bio-based carbon content is expressed as a fraction of the biogenic carbon (14C) to the total amount of carbon in a product.
The procedure for determiming the bio-based carbon content was proposed and validated by interlaboratory testing in CEN/TS 16640. This report is a public report that describes the ap-proach proposed in CEN/TS 16640 (Bio-based products – Determination of the bio-based carbon content of products using the radiocarbon method) for the bio-based carbon content determination.
Accordingly to CEN/TS 16640, the bio-based carbon content determination consists of three subsequent steps: first material has to be sampled. Then the sample has to undergo a proper pre-treatment, i.e it has to be converted to the form that is suitable for the 14C measurements. Finally the 14C measurements can be done on the pre-treated sample. CEN/TS 16640 describes the complete method that is recommended to use for the conversion of samples for the 14C analysis. The method is based on the complete combustion of the samples and col-lection of the CO2 that is released during the combustion process. The collected CO2 is then analysed for the 14C content. Representativeness of a sample and its complete combustion are required in order to achieve reliable results on the 14C content. Combustion shall be carried out to achieve as high as possible recovery (at least 95%) of all carbon present in the sample into CO2 in order to yield valid results.
Special care shall be taken in case of products with high water content and therefore with possible combustion difficulties. In such cases the use of combustion aids are recommended. The true biogenic carbon content that originates from the sample itself than needs to be recalculated and corrected taking into account all the carbon and subsequently the 14C that originates from the combustion aid. For samples that contain volatile components it has to be ensured that all carbon that may originate from the volatile part is not lost before combustion. It can be achieved by using chromosorb material in order to absorb the sampled material and prevent leakage and loss of material before combustion.
Having ensured that proper sample preparation and proper sample pre-treatment was done, the interlaboratory testing revealed that both AMS and LSC techniques produce equally reli-able results and both of them can be used for the 14C content determination.
For finalizing CEN/TS 16640, the performance characteristics have to be established. This will be done on a round robin.
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