Patent CA-1183728-A (CA)
Inventor: BASIC JOHN N SR
IPC: F23G5/46
Filed: 1982-03-22
Granted: 1985-03-12
Abstract: TITLE:     INCINERATOR WITH TWO REBURN STAGES AND, OPTIONALLY, HEAT RECOVERY     INVENTOR:  JOHN N. BASIC, SR.     ABSTRACT     An incinerator with a maim combustion chamber leading directly to two consecutive reburn stages.  The main combustion chamber accepts bulk refuse onto a hearth floor.  Air jets within the floor and near the roofline provide a generally stoichiometric amount of air for the burning refuse. Of this air, 75% emanates from the nozzles located in the floor. For the designed amount of refuse, the main chamber has a sufficient area to maintain the ratio for the expected heat to the square area to less than about 100,000 Btu/sq.ft. hr.  Similarly, the ratio of the main chamber's volume  is less than about 12,000 Btu/cu.ft. hr.  The combustion gases pass from the main chamber into a first reburn stage.  The throat between the two sections introduces the gas into the latter at an angle of about 60° relative to the direction of travel in the reburn section.          In the first reburn tunnel, a burner maintains the tempera-ture of the gases above a predetermined set point.  Above that set point, the burner assumes a low setting.  Below it, a high setting increases the heat produced.  Alterna-tively, the gas may go to its high setting below a first set point; to its low setting above a second set point and proportionate at temperatures between them.  This chamber also receives outside air to assist in the actual combus-tion process.  Above its particular set point, the involved blower system provides additional air to keep its tempera-ture from rising excessively.  From the first reburn chamber, the gases go to a second reburn chamber to com-plete the combustion.  There, they receive additional oxy-gen for this purpose.  At temperatures above a set point determined near the third chamber, additional air enters to prevent excessive temperatures.   At an even higher set point, various actions can occur to keep the system's temperature at a controllable level:  the burner may turn entirely off, the loader for the refuse may stay operating, and the air in the first stage may go to a low setting to slow down the combustion.  The double reburn tunnel may also find use as a fume burner for a source of hydrocarbon-containing gases.  The entering gases should have a veloc-ity of about 40 ft./sec. and the entrained particles should have a size less than about 100 microns.  In either event, the second and third stages have a circular cross-section surrounded by a double wall plenum through which ambient air travels immediately prior to entering the chambers.  By responding to fluctuating combustion conditions, the incin-erator system can produce an output gas having less than about 45 p.p.m. of nitrogen oxides, less than about 10 p.p.m. of hydrocarbons, and 10 p.p.m. of carbon monoxide.          Moreover, its output gas will contain less than about 0.10 grains of particulate matter per standard cubic foot of gas (corrected to 12% CO2) when the entering refuse contains less than 2% chlorine and no more than the amount of pig-ment material found in normal municipal waste.