Flash pyrolysis of organic solid waste employing ash recycle

Claim 1

In a process for the treatment of solid waste in which a waste solid is separated into an organic fraction and solid organic solid waste fraction containing entrained particulate inorganic constituents and in which after comminution and drying the organic solid is pyrolyzed to form a carbon containing solid residue of pyrolysis, a condensable pyrolytic oil and gas, the improvement which comprises: (a) combining and transporting the dried comminuted organic solid waste fraction, including the particulate inorganics, which fraction is of a particle size in which the largest particle dimension is less than one inch, a carrier gas which is nondeleteriously reactive with the pyrolysis products, and a hot particulate inorganic solid heat source formed from decarbonization of the carbon containing solid residue of pyrolysis and having a bulk density from about 35 to about 70 lbs./cu. ft. as the prime source of heat for pyrolysis under transport turbulent flow conditions through a pyrolysis zone maintained at a temperature from about 600° F. to less than the sintering temperature of the inorganic solid heat source for a time sufficient to form from the organic solid waste the carbon containing solid residue and condensable pyrolytic oils and gases; (b) separating the carbon containing solid residue of pyrolysis in admixture with the inorganic solid heat source from the condensable pyrolytic oils and gases; (c) decarbonizing at least a portion of the carbon containing solid residue of pyrolysis to form additional hot inorganic solid heat source, the decarbonization of the carbon containing solid residue of pyrolysis occurring at a temperature below the fusion temperature of the resultant inorganic solid heat source; (d) recycling at least a portion of the formed hot inorganic solid source of heat to the pyrolysis zone.