Hydrothermal carbonisation (HTC) is a thermochemical conversion process performed in pressurized water (2-6 MPa) between 180 and 260°C. The main product is a carbonaceous solid residue (hydrochar). Various applications are foreseen for hydrochar: combustion, gasification, adsorption, catalysis, soils amendment, hard carbon for Na-ion batteries, …, each of them requiring specific properties.
The objective of the thesis is to characterise and better understand the origin of several physico-chemical properties of biomass hydrochars. A special attention will be paid to hydrophobicity and drying capacity, to physical and textural characteristics of the particles (porosity, granulometry, specific surface), as well as to chemical characteristics (composition). The influence of biomass type and HTC conditions on these properties will be investigated.
The approach will consist in: experimentations in batch reactors on pre-selected biomass resources, together with use of different characterisation techniques for hydrochars; analysis of results aiming at determining links between the characteristics, elucidating the links between the resource and its hydrochar properties as a function of operational conditions.