In a method for treating waste gases containing volatile toxic or odorous compounds in the form of a mist, using a regenerative incinerator system of the type comprising at least three regenerators, each of said regenerators containing a packing material, and having one end always in open communication with a combustion chamber common to all said regenerators and at another end, directing means to allow for a flow of gases in and out of said regenerators, said method having a cycle of operation comprising:
- a) during a first period of time:
- directing said waste gases first through a first one of said regenerators so that said waste gases are heated by contact with the packing material contained in said first regenerator;
- then through said combustion chamber to oxidize said compounds contained in said waste gases;
- and finally through a second one of said regenerators to cool the gases from the combustion chamber by contact with the packing material contained in said second regenerator, such a contact causing said packing material to be heated, the gases leaving said second regenerator being clean and discharged to the atmosphere;
- and
- simultaneously recycling part of said clean gases as a purging gas through a third one of said regenerators for purging said third regenerator of any waste gases or of said compounds remaining therein, said purging gas being fed into an end of said third regenerator opposite to the one end thereof in communication with the combustion chamber so that the purging gas leaving said third regenerator is fed into the combustion chamber to remove any contaminant that would be carried by said purging gas before said purging gas is discharged from the system together with the clean gases;
- b) during a second period of time:
- directing the waste gases first through said second regenerator, then through the combustion chamber and finally through said third regenerator which was purged;
- and
- simultaneously recycling part of the clean gases leaving said third generator as a purging gas into said first regenerator;
- and
- c) during a third period of time:
- directing said waste gases first through said third regenerator;
- then through the combustion chamber and finally through said first regenerator which was purged;
- and
- simultaneously recycling part of the clean gases leaving said first generator as a purging gas into said second regenerator;
- and
- d) repeating the previous steps in the same order to provide for a continuous flow and treatment of said waste gases through the system, together with a substantial recovery of the heat contained in said waste gases after combustion thereof in the combustion chamber, the improvement comprising:
- e) raising the temperature of said part of said clean gases used as a purging gas prior to entry of said purging gas into each of said first, second and third regenerators to be purged so as to increase volatilization and removal of said compounds remaining in said regenerator after the passage of said waste gases.