NOVELTY - Device for exothermic wet chemical high-pressure reactions, preferably hydrothermal carbonization of reactants in the form of a biomass (4), comprises: a reaction container (8) exhibiting a reaction chamber (6) for exothermic wet chemical high-pressure reactions of the reactants; and a device for recovering and transmitting heat released into the reaction container during the exothermic wet chemical reaction for heating the reactants.    USE - The device is useful for exothermic wet chemical high-pressure reactions, preferably hydrothermal carbonization of reactants in the form of a biomass.    ADVANTAGE - The device allows maintenance of a high pressure reaction in the reaction chamber under the continuous supply of the reactants in the reaction chamber, and has simple construction.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) the heat storage device for exothermic wet chemical high-pressure reactions, preferably hydrothermal carbonization of the reactant in the form of the biomass, comprising the heat storage container having a liquid heat storage medium, where at least one thermally coupled heat exchanger pipeline is formed in the heat storage container, and a liquid and/or gaseous fluid is passed into the thermally coupled heat exchanger pipeline to store the heat in the heat storage container and/or to withdraw the heat from the heat storage container, and a heat accumulator thermally coupled with the heat storage medium is arranged in the heat storage container, that comprises a phase change material with a characteristic phase change temperature for storing the heat as a latent heat storage; and    (2) hydrothermal carbonization of the biomass, comprising heating the biomass supplied in the reaction chamber of the reaction container with processing heat obtained from the hydrothermal carbonization reaction.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic representation of the device for hydrothermal carbonization of the biomass.    Biomass (4)    Reaction chamber (6)    Reaction container (8)    Preliminary container (9)    Supplying channel (10)