Process for conditioning flue gases in waste material incineration plants with heat utilization

A process for conditioning flue gases in waste material incineration plants with heat utilization having a combustion chamber with a combustion grate, a flue gas cooler serving as the heat utilizer and a gas cleaner connected in series with said combustion chamber, said process comprising the steps of:

• introducing secondary air into the reduction-oxidation zone of said combustion chamber above the combustion grate and before said flue gas cooler;
• spraying water into said reduction-oxidation zone to moisten the flue gases before they enter said flue gas cooler, said water being sprayed into said reduction-oxidation zone simultaneously with the introduction of said air;
• and
• maintaining said air and water in a separate, unmixed condition prior to their introduction into said reduction-oxidation zone;
• said water and secondary air being regulatably introduced together into the reduction-oxidation zone of the combustion chamber thereby creating an oxygen excess sufficient for the subsequent burning of unburned, combustible, volatile material in said flue gases, the CO-oxidation of the unburned material is catalytically accelerated by a homogeneous water gas reaction and simultaneously the laminar flow of the combustible gases is converted into a turbulent flow to facilitate mixing the gases in combustion chamber, and whereby a predetermined maximum gas temperature is maintained, and a flue gas water content of at least 10 Vol. % is maintained prior to its discharge from the combustion chamber.

Apparatus for conditioning flue gases in waste material incineration plants with heat utilization having a combustion chamber with a combustion grate, sidewalls and a reflection wall, a flue gas cooler serving as the heat utilizer connected at the gas discharge of the combustion chamber, and a gas cleaner connected in series with said combustion chamber and said gas cooler, said apparatus comprising:

• a conduit adapted for connection to a source of secondary air;
• a conduit adapted for connection to a source of water;
• at least one first mixing nozzle opening into said combustion chamber from at least one of said side walls;
• at least one second mixing nozzle opening into said combustion chamber from said reflection wall, said reflection wall overlying the final combustion zone of said combustion grate;
• and
• means for connecting both said water and secondary air conduits to said first and second mixing nozzles for injection thereof into said combustion chamber;
• whereby an oxygen excess sufficient for the subsequent burning of unburned combustible volatile material in said flue gases is provided, the CO-oxidation of the unburned material is catalytically accelerated by a homogeneous water gas reaction, the laminar flow of the combustible gases is converted into a turbulent flow to facilitate mixing the gases in the combustion chamber, a predetermined maximum gas temperature is maintained, and a flue gas water content of at least 10 Vol. % is maintained prior to its discharge from the combustion chamber.