Rotary furnace for waste pyrolysis, includes gas outlet channel running through combustion tube to raise temperature of gaseous fuel product

摘要

A connection is made between the pyrolysis tube (12) and the pyrolysis gas offtake (74) through the gas channel (74). This channel runs through part of the internal chamber (32) of the combustion tube (26, 30). The gas channel is a tube with an end section projecting through the output opening for solids (16) and into the pyrolysis tube (12). Seals (18, 84) make the pyrolysis tube largely gas-tight with respect to the combustion tube (26, 30). The seals (18, 44) comprise a cylinder (84) locally surrounding the gas tube (74) and coaxial to the pyrolysis tube (12). The pyrolysis tube carries internal helical conveying ridges which rest against the outside of the cylinder (84). The pitch between ridges is sufficiently small, that preferably two turns always cover the axial extent of the cylinder. The pyrolysis tube extends through an axial passage (82) into the cylinder (84). Between the inner surface of the passage and the tube there is a labyrinth seal (92). A conical section (86) is located at the end of the pyrolysis tube; this tapers down, towards the labyrinth seal. In operation, pyrolysis gas produced in the pyrolysis tube is carried off for use in heating. Before this, it is raised to a higher temperature. The gas is passed through the combustion tube (26, 30) of the furnace (10), where the temperature exceeds that in the pyrolysis tube. An independent claim IS INCLUDED FOR the method of operation.