Apparatus for producing product gas from carbonaceous feedstock with heat pipes

Apparatus for producing product gas from carbonaceous feedstock by allothermic steam gasification, with a heat source with a combustion chamber, at least one reforming reactor with a feed device for the feed materials to be gasified and a product gas outlet, a heat pipe assembly with a heat transfer medium for the transport of the necessary for the allothermic steam gasification heat from the heat source in the at least one reforming reactor, wherein said heat pipe assembly comprises a plurality of elongated heat pipes with an annular cross-section, characterized, that the heat transfer medium of the heat pipe assembly is a mixture of substances containing sodium and potassium