Process for melting down combustion residues into slag

In a process for incinerating solid waste material that comprises carbonizing said solid waste material into a carbonization gas and solid carbonization product in a gas generating travelling grate reactor, and incinerating at least a portion of said solid carbonization product in a rotary kiln;

• the improvement that comprises:
• disposing said solid waste material on said travelling grate;
• feeding oxygen containing grate air below said grate whereby combining said solid waste material with a sub-stoichiometric quantity of oxygen under low temperature conditions sufficient to carbonize said waste material on said grate and form still combustible solid residue on said grate and combustible gas above said grate while retaining a substantial portion of the energy contained in said solid waste material in said combustible solid residue and said combustible gas;
• combining all of the contents of said travelling grate reactor, including said combustible solid residue and said combustible gas, with additional oxygen in a transition zone that is intermediate between said travelling grate and said rotary kiln, wherein the total amount of oxygen in said transition zone is at least stoichiometric with respect to combustible materials present in said transition zone;
• passing the entire contents of said transition zone into said kiln and incinerating substantially all combustible values in said residue and gas in said kiln at a temperature that is higher than the temperature in said travelling grate;
• and
• recovering substantially incombustible residue.

A process of burning waste in a combustion plant having a gas generator equipped with a travelling grate and a following rotary kiln comprising the following sequence of steps:

• disposing said waste on said travelling grate;
• low temperature carbonizing said waste by contact with oxygen whereby heating said waste while on said travelling grate under such conditions that still combustible pyrolysis residue and combustible low temperature carbonization gasses form from said waste,
• continuously introducing an oxygen containing gas into said gas generator in a region of transition from the gas generator to the rotary kiln so that the pyrolysis residues, as well as the low temperature carbonization/combustion gas, together with added oxygen, continually pass through said transition region into the rotary kiln, wherein the only exit from said gas generator is through said transition region into said kiln;
• and
• maintaining a high enough temperature in said kiln to incinerate substantially all combustible components of said pyrolysis solid and said carbonization gas.