Ποιοτικός έλεγχος πλίνθων (μπρικετών) ξυλοκάρβουνου απο την ελληνική αγορά
Ποιοτικός έλεγχος πλίνθων (μπρικετών) ξυλοκάρβουνου απο την ελληνική αγορά
Date
2023-02-07
Authors
Γεωργάκη, Μαρία
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Abstract
Charcoal is one of the first materials human has used since ancient times. Rock
paintings in caves and primitive hearths in the form of a handful of stones in a circle
are proof of charcoal use. Charcoal has been, and remains tο this day, an important
source of energy for centuries. Nowadays charcoal is used to generate energy, mostly
for cooking and heating purposes, but it also plays an important role in metallurgy and
other sectors of heavy industry. Up to 17% of the wood used worldwide is converted to
charcoal. Global charcoal production keeps increasing and it is expected to grow more
in the coming decades since charcoal is considered cleaner than the fossil fuels (FAO,
2017). While charcoal is a popular barbecue fuel choice, in the form of lumps and
briquettes, very little is known about its ingredients, properties and manufacturing
process. While many studies have been conducted to assess air pollution and human
health risks from exposure to barbecuing emissions, there is no application of the
international standards and policies to ensure the quality of BBQ fuels.
Charcoal briquettes are made of charcoal fractions. Fine charcoal particles and dust are
mixed with water and starch binder, which are subsequently dried to form the
briquettes. The European standard EN 1860-2 (2005) defines the values of barbecue
charcoal briquettes characteristics. According to this standard the moisture shall not be
above 8 wt.%, the ash yield shall be ≤ 18 wt.%, the fixed carbon ≥ 60 wt.% and the
total of all detected inadmissible additions should not exceed 1% by volume.
The aim of this study is to investigate the quality of charcoal briquettes from the Greek
market, by applying organic petrographical techniques. In total nine packages imported
to the Greek market are examined, five from Europe, three from Africa and one from
Asia.
According to the EN 1860-2 (2005) standard, the moisture of the samples is within the
permissible limit, the ash values slightly exceed the maximum threshold in two of the
tested samples and the fixed carbon is below the standard limits in four samples. The
ultimate analysis shows low nitrogen and high carbon values in four of the samples.
Evaluation of the X-ray diffraction data indicates similar mineralogical features for all
samples. The dominant minerals are quartz, calcite, clays (mostly mixed illite-
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montmorillonite), mica, K-feldspars, plagioclase, whewellite, gypsum, chlorite,
anhydrite, and pyrite.
The quality control based on reflected light microscopy, allows the identification of the
range of biomass derived charcoals, and impurities. The latter include raw (fresh)
biomass, mineral matter, plastics, rust, metal, coal particles, and pyrolytic carbon.
The petrographic analysis reveals that the impurity content exceeds 1 vol.% in all
samples, and actually four out of nine samples consist almost exclusively of raw coal
particles.
Based on the results and according to ΕΝ 1860-2 (2005) all the examined charcoal
briquettes samples are considered unsuitable for barbecue use.
In light of the above and considering the public health hazard that is posed by using
grill fuel of questionable quality, the petrographic analysis of charcoal briquettes should
be a prerequisite for getting authorization to enter the market.
Description
Keywords
Charcoal briquettes, Barbeque charcoal briquettes, Charcoal briquettes impurities, Greek market