A process for the gasification of wet biomass. The process comprises heating wet biomass at a pressure in the range of from 22.1 MPa to 35 MPa. The wet biomass is heated from a temperature of at most T1 to a temperature of at least T2 by heat exchange with a first heating fluid. The gasification product is further heated. The further heated gasification product is used as the first heating fluid, upon which the further heated gasification product is cooled down from a temperature of at least T3 to a temperature of at most T4. The temperatures T1, T2, T3 and T4 can be calculated by using certain mathematical formulae. Also claimed: a reaction apparatus for the gasification of wet biomass.