Method and apparatus for burning combustible waste materials

An apparatus for incinerating waste materials which comprises:

• a rotary tubular kiln,
• heating means for generating heated combustion air,
• said heating means being arranged for indirect heat transfer between the heated flue gas of said kiln and combustion air by the circulation of a finely divided heat exchanging solid, said heating means including at least first and second heat exchangers, said first heat exchanger being arranged for direct heat transfer from said heat exchanging solid to air, and
• means for conducting hot flue gas and heat exchanging solid to said second heat exchanger.

A method for burning combustible waste materials which comprises:

• introducing said waste materials with combustion air into a rotary tubular kiln at a temperature sufficient to incinerate said waste materials and generate high temperature flue gases,
• heat exchanging at least a portion of said high temperature flue gases with a solid heat exchange medium in a heating stage,
• passing the thus preheated solid heat exchange medium into a cooling stage to transfer heat to a stream of combustion air to thereby preheat said combustion air to a temperature of from 300.degree. to 800.degree. C., and
• recycling at least a major part of said heat exchange medium sequentially through said heating stage and said cooling stage.