Thermochemical upgrading of cereal brans into pyrolytic chars for solid fuel applications

Abstract The growing production of cereals in Europe generates large quantities of milling by-products, including cereal brans, whose valorisation is important in the context of circular bioeconomy and renewable energy production. Although brans are commonly used in food and feed chains, low-grade or surplus fractions may require alternative management pathways. This study evaluated the potential of selected cereal brans, namely spelt, oat, wheat, rye, barley, durum wheat, triticale and millet brans, as feed-stocks for the production of pyrolytic char intended for energy recovery. The brans were pyrolysed at 500 °C, and the resulting chars were assessed in terms of solid yield, ash content, higher heating value and energy-related indicators. The char yield ranged from 30.27 to 37.04%, depending on the feedstock. Pyrolysis increased the higher heating value from 16.58 to 22.80 MJ/kg in raw brans to 24.45–30.15 MJ/kg in the corresponding chars, confirming the effectiveness of carbonisation in improving the energy density of the solid product. However, ash content also increased markedly, from 3.69 to 7.36% in raw brans to 11.41–23.31% in the chars, indicating that mineral concentration is a key constraint for combustion-oriented applications. The integrated evaluation of heating value and ash load showed that oat, rye and durum wheat chars offered the most favourable balance between high energy content and relatively low ash burden. To conclude, cereal brans can be considered promising feedstocks for thermochemical upgrading into charcoal-like solid fuels, particularly when they are unsuitable for food or feed uses.