An innovative solution for waste utilization

For preheater kiln systems, experience has shown that it is possible to substitute upwards of 25% of the fuel with waste material in "lump" form such as whole car tires. However, most kiln systems supplied today are of the precalciner type where typically only 40% of the fuel is fired in the rotary kiln, with the balance fired to the calciner. This means that lump waste fuels may typically substitute only 10% of the total fuel requirement of the kiln system. This paper presents an innovative technology that facilitates the burning of waste-derived fuels, especially large-sized alternative fuels, that otherwise cannot be economically ground or shredded to the fineness needed to 'burn in suspension' as required by modern precalciner kiln systems. The device is a large, rotating furnace hereto referred to as a "disc" that is simplistically capable of controlling two primary requirements for complete combustion: retention time and temperature. The disc, continuously satisfies these two requirements making it possible to burn alternative fuels (e.g. whole automobile tires) in the calciner that, otherwise, would not be possible due to their poor gas-suspension and/or poor burnout characteristics. The disc is an extremely simple combustion device which may be installed as part of any new calciner, as well as many existing calciners. As a result of this invention, upwards of 60% or more of the calciner's fuel requirement may be substituted with waste-derived fuels in lump form.