摘要:
The device according to the invention for drying and torrefying at least one carbon-containing substance stream in a multiple-hearth furnace substantially consists of a drying zone, which has a supplying device for supplying a carbon-containing substance stream, an outlet for removing a water-vapour-containing drying gas stream and an inlet for returning at least part of the drying gas stream, a torrefying zone for degassing the substance stream dried in the drying zone, which has an outlet for discharging a torrefied substance stream, at least one inlet for an exhaust gas and an outlet for a torrefying gas stream, a heat exchanger for heating up the drying gas stream, wherein the outlet of the drying zone is in connection with the inlet of the drying zone via the heat exchanger, a combustion unit, wherein the outlet of the torrefying zone is connected to the inlet of the torrefying zone via the combustion unit and the heat exchanger, wherein a torrefying gas stream removed via the outlet of the torrefying zone is burned in the combustion unit and the exhaust gas thereby produced is used in the heat exchanger for heating up the drying gas stream and is supplied to the torrefying zone, wherein the drying zone and the torrefying zone have two gas circuits that are separate from one another.