Abstract: A system for regenerating or manufacturing activated carbon wherein exhaust gases and vapors for various lower sections of the furnace are recycled in up-flow fashion to higher sections of the furnace.

Abstract: This invention relates to a system for regenerating or manufacturing activated carbon wherein the exhaust gases and vapors from various sections of the furnace are supplied to other sections of the furnace in a recycling manner or are simultaneously cleaned and transformed into fuel gas. In a down-flow embodiment, the water vapor and calorific gasses generated in excess in the drying and devolatilization sections, respectively, are provided, either directly or through a combustion chamber, to the activation section. In an up-flow embodiment, heat from the activation section is recycled to the drying and devolatilization section and the down-flow brings the water vapor from the drying section and volatile material from the devolatilization section into the activation section where it can be effectively used.

Abstract: This invention relates to a system for regenerating or manufacturing activated carbon wherein the exhaust gases and vapors from various sections of the furnace are supplied to other sections of the furnace in a recycling manner. In a down-flow embodiment, the water vapor and calorific gasses generated in excess in the drying and devolatilization sections, respectively, are provided, either directly or through a combustion chamber, to the activation section. In an up-flow embodiment, heat from the activation section is recycled to the drying and devolatilization section and the down-flow brings the water vapor from the drying section and volatile material from the devolatilization section into the activation section where it can be effectively used.

Abstract: A method and system for controlling the combustion in a furnace in which the flue gas generated by the burning in the combustion zone is fed back to the combustion zone through a recirculation path to cool the combustion zone so that the temperature is below the melting or softening point of the residual ash in the solid materials. Water is heated and vaporized by the flue gas so as to cool the flue gas. Generated water vapor is also introduced to the combustion zone to increase the burning rate.

Abstract: A multiple hearth furnace having a drying zone, a combustion zone and a cooling zone includes a recirculation loop that recycles exhaust gas from the drying zone to the cooling zone. In some embodiments, a first control loop including a temperature measurement device that measures temperature in the combustion zone controls fan speed of a recirculation fan that drives the recirculation loop. A second control loop monitors recirculation fan temperature and overrides the first control loop if the recirculation fan temperature exceeds a predetermined maximum. A third control loop controls air flow into the furnace.

Abstract: Method and apparatus for treating waste material in a counterflow furnace wherein the material is introduced at one end thereof and the processed material is discharged from the other end, while air is simultaneously introduced thereto and the gases of combustion are caused to flow in counter-current direction with respect to the material being processed and are exhausted at the first end of the furnace, and wherein the furnace has a natural tendency to form zones of processing including sequentially from the first end of the furnace, a drying zone, a charring and volatile burning zone, a fixed carbon burning zone and an ash cooling zone, the method comprising the steps of bleeding secondary exhaust gases from the middle of the furnace substantially between the fixed carbon burning zone and the charring and volatile burning zone, and adding air to the furnace in the charring and volatile burning zone.

Abstract: Method and apparatus for treating waste material in a counter-flow furnace wherein the material is introduced at one end thereof and the processed material is discharged from the other end, while air is simultaneously introduced thereto and the gases of combustion are caused to flow in counter-current direction with respect to the material being processed and are exhausted at the first end of the furnace, and wherein the furnace has a natural tendency to form zones of processing including sequentially from the first end of the furnace, a drying zone, a charring and volatile burning zone, a fixed carbon burning zone and an ash cooling zone, the method comprising the steps of bleeding secondary exhaust gases from the middle of the furnace substantially between the fixed carbon burning zone and the charring and volatile burning zone, and adding air to the furnace in the charring and volatile burning zone.

Abstract: Method and apparatus for treating waste material in a counterflow furnace wherein the material is introduced at one end thereof and the processed material is discharged from the other end, while air is simultaneously introduced thereto and the gases of combustion are caused to flow in counter-current direction with respect to the material being processed and are exhausted at the first end of the furnace, and wherein the furnace has a natural tendency to form zones of processing including sequentially from the first end of the furnace, a drying zone, a charring and volatile burning zone, a fixed carbon burning zone and an ash cooling zone, the method comprising the steps of bleeding secondary exhaust gases from the middle of the furnace substantially between the fixed carbon burning zone and the charring and volatile burning zone, and adding air to the furnace in the charring and volatile burning zone.

Abstract: The present invention is directed to method and apparatus for treating waste material in a counter-flow furnace wherein the material is introduced at one end thereof and the processed material is discharged from the other end, while the gases of combustion are caused to flow in counter-current direction with respect to the material being processed and are exhausted at the first end of the furnace, and wherein the furnace has a natural tendency to form zones of processing including sequentially from the first end of the furnace, a drying zone, a charring and volatile burning zone, a fixed carbon burning zone and an ash cooling zone, a method characterized by the step of adding an oxidant including water vapor to the fixed carbon burning zone.