HYDROTHERMAL TREATMENT OF BIOMASS

The present invention concerns an improved process for a process for the treatment of biomass, comprising (a) subjecting biomass to hydrothermal treatment in a hydrothermal reactor by immersing the biomass in a treatment liquid, wherein an effluent drained from step (b) or (c) is used as treatment liquid; (b) draining the liquid from the reactor via a liquid outlet to obtain a liquor and simultaneously or subsequently introducing another washing liquid into the reactor, wherein the washing liquid is pre-heated to a temperature 30 °C below operational temperature of step (a) or higher before being introduced into the reactor, (c) draining the reactor to obtain washed hydrothermally treated biomass and an effluent, wherein at least one of step (a) and (b) is performed at a temperature in the range of 100 - 250 °C. The invention further concerns a solid fuel and a liquor obtained by the process according to the invention, as well as a hydrothermal treatment facility to operate the process according to the invention.