Pyrolysis method in connection with a boiler and a pyrolysis apparatus

A pyrolysis apparatus, comprising a fluidized bed combustion furnace, means for fluidizing carrier material in the furnace, a pyrolyzer chamber, a flue gas channel exiting the furnace, a separator for separating carrier material from the flue gas channel and being located higher than the pyrolyzer chamber, and a connecting conduit between the separator and the pyrolyzer chamber for feeding carrier material by gravity to the pyrolyzer chamber, the apparatus further comprising a supply inlet for supplying fuel to be pyrolyzed to the pyrolyzer chamber, fluidizing gas supply means arranged in the pyrolyzer chamber for fluidizing a mixture of carrier material and fuel, and an outlet arranged in the upper part of the pyrolyzer chamber in connection with a space above the fluidized mixture of a carrier material and fuel for taking condensable gaseous substances that have separated from the fuel to be pyrolyzed out of the pyrolyzer chamber, and a condenser for condensing the condensable gaseous substances,

• the pyrolyzer chamber being bordered by the fluidized bed combustion furnace, being parallel to one wall of the furnace, and comprising a middle part and ends on both sides of the middle part, the connecting conduit for carrier material forming a carrier material inlet to the middle part of the pyrolyzer chamber, and the ends comprising carrier material return outlets to the fluidized bed combustion furnace, gas locks being provided by means of flow by gravity of said carrier material between the separator and the fluidized bed combustion furnace, said gas locks comprising:
• a first gas lock being located adjacent the carrier material inlet to said middle part of the pyrolyzer chamber and comprising an inlet for carrier material that is located in a lower position than an outlet for carrier material succeeding said inlet, and
• second gas locks being located at the ends of the pyrolyzer chamber and comprising inlets for carrier material that are located in a lower position than said carrier material return outlets succeeding said inlets.