Co-Hydrothermal Carbonization of Grass and Olive Stone as a Means to Lower Water Input to HTC

One drawback of biomass hydrothermal treatment (HTC) is the need a water supply, which especially important in case lignocellulosic biomass. This study has investigated synergy resulting from co-HTC two residual materials that significantly differ their physico-chemical compositions: (a) olive stone, OS, hard and high-quality biomass, with low N content, whose potential to give high heating value briquette by HTC been proven, (b) fresh grass pruning, GP, as it gathered gardens, moderate fraction, calorific value. The work specifically focuses on saving can be attained when liquid product produced one them (grass, 80% moisture) supply part needed other (olive stone) both are subjected simultaneously. It was found that, instead water, an additional amount GP added (in particular 40 out 110 g provided 54 GP), more basic processing obtained (pH increased 40%, relation single OS processes). turn did not have remarkable effect final SY at any temperatures studied (200 220 °C), C densification. Other features such content hydrochars showed rise hybrid processes, 0.2% 3.3%. were affected products because presence HC surface structure, hydrophobicity, functionalities thermal stability towards pyrolysis; also changes mineral biomasses there blended. Proving like hydrothermally treated process involving less without being detrimental terms energy densification, open field research aimed make processes efficient hydric balance.