Incineration (Heat recovery) Plant
Social needs for minimizing the impact and high efficiency in waste incineration has been growing recently from the standpoint of even more minimizing the impact to the environment and advancement of thermal recycling. Plant & Infrastructure Company, Ltd. meets the various needs by developing Kawasaki Advanced Stoker-type Incinerator, which has been highly developed from Stoker-type Incinerator with its credibility supported by reputation of long standing and by developing gasification and melting system, which enables to utilize the combustible gas generated by gasifying the waste for melting process. Kawasaki has delivered waste incineration facilities these systems as flue gas processing systems and has developed various systems and technologies in order to return the clean air to the environment after eliminating pollutants contained in the gas from incinerator such as hydrogen chloride (HCI), sulfur oxides (SOx), nitrogen oxides (NOx). Through its extensive experience, Kawasaki provides flue gas processing system fitted to many plants as well as waste combustion system.
Advanced Stoker System
Parallel flow type incinerator greatly develops the turbulent mixing of flue gas and enables low air ratio, high-temperature combustion by inverting flue gas forcibly and by installing water cooled partition ceiling in the furnace parallel to the direction waste carried. Water cooled grates save combustion loss and improves its credibility since it keeps working in case of breakage and easy maintenance by indirect water cooled structure. It enhances low air ratio, high-temperature combustion by flue gas recirculation that filtered flue gas is blown into furnace. It intends to reduce the energy loss with flue gas reduction, downsize the flue gas treatment system and minimize the formation of toxic substances.
Fluidized Bed Type Gasification and Melting System
Waste is partially combusted (gasified) in the partial combustor at low temperature (fluidized bed temperature: 500~580℃) and with low air ratio. The unburned gas and unburned substances generated therein are sent to the rotating melting furnace and combusted supplying the air. And the ash in the waste is melted into slag at high temperature, about 1300℃. It reduces the emission of CO2 by using its own energy to gasify and melt itself. Flue gas is incinerated using high-temperature in the secondary combustion chamber and minimizes the volume of dioxin and the heat is recovered in the boiler and utilized for highly efficient power generation. Steel, aluminum, slag generated in the process can be utilized as resource. The separation method is another Kawasaki's own method which enables to melt and generate power more efficiently by separating the unburned gas and unburned substances via the cyclone at the exit of the partial compustor.
Shaft Type Gasification and Melting System
This gasification and melting system has a wide range of application for municipal waste, sludge, unburied waste, etc. By blowing oxygen at the lower part of the furnace, the amount of generated gas can be reduced and less space is required for the plant. Like a fluidized bed type, this system melts waste at high temperatures and reduces the volume of waste to approximately 1 / 40 by producing slag that can be used for construction material. Pyrolysis gas is sent to the secondary combustion chamber and combusted at high temperatures with air substances and at the same time the waste heat is utilized for power generation.
Flue Gas Processing System
- Spray Gas Cooler
Quick cooling of gas prevents the dioxin reformation.
- Bag Filter
The fly ash in flue gas, as well as the SOx and HCI that has reacted with and been absorbed by such substances as slaked lime, are eliminated when they attach to the cylindrical filtration cloth.
- Wet Scrubber
Hydrogen chloride and sulfur oxides, as well as mercury, are removed from the flue gas. By the reheater, white plumes can be prevented.
- Activated Carbon Absorption Tower
Discharge the dioxin in the flue gas absorbed in activated carbon. Activated carbon charged from the upper part of the tower is moved down periodically and discharged at the bottom of packed bed.
- Catalytic Denitration Reactor
Besides removing the nitrogen oxide contained in flue gas as nonpolluting nitrogen and water by blowing ammonia gas and catalyst, dioxin can be decomposed and removed.