Described is a pyrolysis system including an entrained flow pyrolyzer having an opening through which biomass can be added. The pyrolyzer also has an inlet for hot exhaust gas, an outlet for pyrolyzed biomass and an outlet for syngas. The system has a burner for producing hot exhaust gas and a conduit between the burner and the hot exhaust gas inlet. A syngas extraction means for extracting syngas from the pyrolyzer. The syngas extraction means extracts syngas from the pyrolyzer at a rate such that the internal pressure within the pyrolyzer never exceeds the pressure external to the pyrolyzer.