Ash sintering gasifier

A method of thermally converting non-radioactive combustible wastes to a substantially non-hazardous, non-leachable, sintered particulate carbon-less ash by-product in a kiln having a plurality of reaction zones, the kiln including first and second ends and a body provided between the first and second ends that defines a cavity having a refractory lining that provides resistance to heat conduction, the body having a length-to-diameter ratio and a longitudinal axis oriented substantially horizontal, wherein the length-to-diameter ratio and the resistance to heat conduction provide a temperature gradient within the cavity that forms separate reaction zones during operation, the method comprising:

• controlling a flow rate through the body including:
• the flow rate of waste that enters at the first end of the kiln,
• the flow rate of oxidant gas that enters at the second end of the kiln, the second end being opposite to the first end;
• and
• detecting a temperature value of the waste within the separate reaction zones;
• and
• adjusting the flow rates of the waste and the oxidant gas through the body based on the detected temperature value to maintain the separate reaction zones at preselected conditions.

An apparatus that receives waste and transfers its enthalpy to a flue gas for beneficial use, the apparatus minimizing air pollution and by-product solid residue pollution by thermally processing the waste to produce a carbon free residual mineral, while also minimizing air pollution emissions, the apparatus comprising:

• a kiln having:
• first and second ends;
• a body provided between the first and second ends that defines a cavity having a refractory lining that provides resistance to heat conduction, the body having a length-to-diameter ratio and a longitudinal axis oriented substantially horizontal, wherein the length-to-diameter ratio and the resistance to heat conduction provide a temperature gradient within the cavity that forms separate reaction zones during operation;
• a first inlet port provided at the first end to receive waste and a first outlet port provided at the second end to expel ash by-product;
• a second inlet port provided at the second end to receive oxidant gas and a second outlet port provided at the first end to expel fuel gas;
• flow rate controllers provided at the first inlet port and the second inlet port to control a flow rate therethrough;
• a thermal sensor that measures a temperature value of the waste within the separate reaction zones;
• and
• a processor that is electrically coupled to the flow rate controllers and the thermal sensor, the processor having instructions executable to:
• receive signals from the thermal sensor indicating the temperature value of the waste within the separate reaction zones;
• and
• control the corresponding flow rate controllers, based on the signals received from the thermal sensor, to adjust the flow rates therethrough to maintain the separate reaction zones at preselected conditions;
• a reformer fluidly coupled to the kiln, the reformer receives the fuel gas, a first stream of recycled flue gas, and a first stream of air to auto-thermally produce a reformed fuel gas and destroy pollutants in the fuel gas at a first temperature;
• a burner fluidly coupled to the reformer, the burner receives a second stream of recycled flue gas and a second stream of air to oxidize the reformed fuel gas at a second temperature that prevents formation of nitrogen oxide, the second temperature being lower than the first temperature;
• a quench chamber fluidly coupled to the burner, the quench chamber receives flue gas from the burner that is quenched with a third stream of recycled flue gas;
• and
• a heat recovery system fluidly coupled to the reformer, the burner, and the quench chamber to provide the first, second, and third streams of recycled flue gas, respectively.