Performance of the Fluidized-bed Incineration Facilities and their Potential
In the course of equipment improvement work of a non-shredding type fluidized-bed incineration facility, which is an original technology of EBARA, a low excess air ratio combustion technology composed of a slow combustion system and exhaust gas recirculation has been introduced. During operation with a combustion air ratio of 1.27, the CO and NOx concentration of the exhaust gas were 2.4 ppm and approximately 20 to 25 ppm respectively, demonstrating operation performance comparable to or higher than the latest, newly constructed incinerators, with a low excess air ratio and reduced CO and NOx concentrations. In this paper, the performance and features of the fluidized-bed incineration technology is explained from a technological perspective by taking the above case as an example, and a future outlook on the potential of fluidized-bed incineration facilities is presented.
Fluidized-bed, Waste incinerator, Low excess air ratio, Combustion control, Exhaust gas recirculation, Carbon monoxide, Nitrogen oxides
High Concentrated and High Efficiency of Anaerobic Digester for Sewage Sludge
- Semi-Dry Anaerobic Digester -
Sewage sludge has high energy potential as continuously usable biomass energy that is collected at treatment plants through the sewerage system. However, in Japan, because the facility costs for the utilization of sewage sludge are high, its effective utilization ratio has been low. Aiming to use the unused biomass energy, we developed a semi-dry anaerobic digester, which is low-cost and high-efficiency sludge digestion equipment. The semi-dry anaerobic digester can not only much more highly concentrate feed sludge than before, but also shorten the digestion period for efficient gas collection. Based on these improvements, the capacity of the digestion tank can be minimized to one-eighth of that of conventional ones, and the amount of effectively usable gas can be increased. This paper introduces the semi-dry system along with the results of demonstration tests.
Methane fermentation, Anaerobic digestion, Sewage sludge, Biosolids, Energy recovery
Lecture on Fundamental Aspects of High Temperature Corrosion and Corrosion Protection
Part 3: High Temperature Corrosion and Corrosion Protection of the Boilers in Waste to Energy Plants
One of the characteristics of incinerators is that the waste used as fuel contains chlorine in high concentration. The chlorine reacts with alkaline metal, etc., to form a chloride, which is deposited as ash adhesion on boiler heat transfer tubes and the like. When this adhered ash melts, the corrosion environment is significantly deteriorated. In addition, the soot blow used to remove the adhered ash promotes the destruction of the corrosion scale and accelerates the metal loss of the heat transfer tubes. The ash adhesion behavior depends on temperature, and chloride is concentrated where the exhaust gas temperature is high, deteriorating the corrosion environment. Accordingly, a good understanding of the adhesion behavior and an appropriate design for the corrosion environment are required in order to prevent the corrosion of heat transfer tubes. This paper explains the metal loss behavior mainly due to the influence of ash adhesion, and also describes examples of corrosion behavior and corrosion protection in the actual plants.
High temperature corrosion, Chlorination, Molten salt, Waste to Energy Plant, Superheater, Boiler, Ash adhesion, Predication of corrosion rate
Improvement work for “Kameda Waste Management Center”
The improvement work of “Kameda Waste Management Center” in Niigata City was completed in March 2016. This work was successfully completed through the ensuring of safe vehicle traffic lines and a carefully elaborated work plan, despite the fact that it had to be carried out under the restrictions of continuation of regular waste disposal operations and a short work period of four months per incinerator. In the performance tests of each incinerator conducted at the end of the work, it was confirmed that the incinerator was able to realize stable operation with a low air ratio of 1.3 and reduced NOx and CO while meeting all reference values. In addition, the amount of CO2 emitted by the center was reduced by 46.3% compared to before the improvement work.
Improvement work, Fluidized-bed, Waste incinerator, Low excess air ratio combustion, Combustion control, Slow combustion, Exhaust gas recirculation, Carbon monoxide, Nitrogen oxides
Construction of Municipal Solid Waste Treatment Plant
“Central Waste Management Center 70-ton/day Incinerator”
We delivered the municipal solid waste treatment plant Central Waste Management Center 70-ton/day Incinerator to the Oyama Wide-Area Hygiene Union, and completed its construction work at the end of September 2016. In the municipal solid waste treatment plant, our latest incineration system, the Ebara HPCC21 Grate-Type Incinerator, operates at a low air ratio of 1.3 or below, generates up to 1 300 kW of electricity with boiler steam, feeds this electricity to existing facilities, and sells the excess electricity. Construction of this facility was a distinctive task, requiring work in a limited area while operating existing facilities.
Municipal solid waste, Grate-type incinerator, Incineration plant, Environment, Low air ratio combustion, Renewable energy