Waste incineration method and apparatus

A method of intermittently incinerating successive batches of waste material comprising the steps of:

• introducing each of said batches into a primary combustion zone;
• substochiometrically combusting said batch within said primary combustion zone with primary air introduced thereinto;
• controlling the rate of said primary air introduced into said primary combustion zone in accordance with changes in the temperature of the combustion gases produced therein whereby said temperature is maintained at a substantially constant selected level;
• conducting said combustion gases into a secondary combustion zone;
• combusting said combustion gases further in said secondary combustion zone by combining secondary air therewith;
• during the peak incineration stage of each batch, controlling the rate of secondary air combined with said combustion gases in said secondary combustion zone in accordance with changes in the temperature of the combustion gases produced therein whereby said temperature is maintained at a substantially constant selected operating temperature level;
• and
• during the loading, initial and final incineration stages of each batch when said selected temperature level cannot be maintained as a result of the rate and combustibility of the combustion gases conducted to said secondary combustion zone being too low, controlling said rate of secondary air combined with said combustion gases in said secondary combustion zone in accordance with a predetermined timed sequence which simulates the increase and decline in the rate and combustibility of the combustion gases conducted to said secondary combustion zone during the loading, initial and final incineration stages whereby the average temperature of the combustion gases produced in said secondary combustion zone is maintained at a relatively high level, but the formation of smoke is prevented.

Apparatus for incinerating successive batches of waste material comprising:

• a primary combustion chamber having a waste material inlet, an air inlet and a combustion gases outlet;
• means for loading successive batches of waste material into said primary combustion chamber connected to the waste material inlet thereof;
• means for introducing primary air into said primary combustion chamber connected to the air inlet thereof;
• means for controlling the rate of air introduced into said primary combustion chamber in accordance with changes in the temperature of the combustion gases produced therewithin and maintaining said temperature at a substantially constant selected level connected to said primary air introducing means and to said primary combustion chamber;
• a secondary combustion chamber having a combustion gases inlet connected to the combustion gases outlet of said primary combustion chamber, an air inlet and a combustion gases outlet;
• means for introducing secondary air into said secondary combustion chamber connected to the air inlet thereof;
• first control means for controlling the rate of secondary air introduced into said secondary combustion chamber in accordance with changes
• in the temperature of combustion gases produced therein whereby said temperature is maintained at a substantially constant selected temperature level during the peak incineration stage of each batch of waste material, said first control means being connected to said secondary air introducing means and to said secondary combustion chamber;
• and
• second control means for controlling the rate of secondary air introduced into said secondary combustion chamber in accordance with a predetermined timed sequence which simulates the increase and decline in the rate and combustibility of combustion gases conducted to said secondary combustion chamber during the loading, initial and final incineration stages of each batch when said selected temperature level cannot be maintained as a result of the rate and combustibility of said combustion gases conducted to said secondary combustion zone being too low whereby the temperature level of the combustion gases produced in said secondary combustion chamber is maintained at a relatively high temperature level, but the formation of smoke is prevented, said second control means being connected to said secondary air introducing means and to said secondary combustion chamber.