Gasification unit, a method for producing a product gas and use of such a method

Abstract

Disclosed is a gasification unit () for producing a product gas. The gasification unit () comprises a co-current or counterflow pyrolysis unit () including a pyrolysis gas outlet () arranged at an upper part () of the pyrolysis unit () and a pyrolysis gas inlet () arranged at a lower part () of the pyrolysis unit (). The gasification unit () further comprises a co-current or counterflow gasifier () including a product gas outlet () arranged at an upper part () of the gasifier () and a gasifier inlet () arranged at a lower part of the gasifier () and coke moving means () for allowing pyrolyzed coke () to move from the pyrolysis unit () to the gasifier (). The gasification unit () also comprises recycling means () arranged to guide at least a part of the pyrolysis gas produced in the pyrolysis unit () from the pyrolysis gas outlet () and back to the pyrolysis gas inlet () and heating device () comprising an input conduit () arranged to guide pyrolysis gas from the pyrolysis gas outlet () to a combustion unit () in the heating device (), wherein the combustion unit () is arranged to least a partially oxidize the pyrolysis gas from the pyrolysis unit (), and wherein the heating device () comprises an output conduit () arranged to guide heating gas generated by the partial oxidization in the combustion unit () to the gasifier inlet (), where in the heating device () is arranged external to the pyrolysis unit () and the gasifier () and wherein said gasification unit () further comprises heat exchange means () arranged for heating at least a portion of the pyrolysis gas before it enters the pyrolysis unit () through said pyrolysis gas inlet () by means of at least a part of the product gas exiting said gasifier () through said product gas outlet (). Furthermore, a method for producing a product gas in a gasification unit () and use of such a method is disclosed.