Hyper 21 Stoker System Demonstration Test at Numanohata Clean Center

Transcription

1 JFE No p Hyper 21 Stoker System Demonstration Test at Numanohata Clean Center NISHINO Masaaki TATEFUKU Teruo YAMAMOTO Hiroshi JFE JFE JFE 21 NOx JFE Abstract: JFE Engineering s advanced stoker type incinerator Hyper 21 Stoker System is the fi rst municipal solid waste incinerator which has adopted the new technology called High-temperature air combustion technology. With this technology, the system realizes stable combustion under low excess air condition, which results in reduction of NOx, dioxins and fl ue gas. The system also treats waste from combustion to ash melting with high effi ciency and a low pollutant emission. This Hyper 21 Stoker System described in this paper demonstrated excellent operational stability and easy operating features, while also minimizing environmental pollutants, improving energy recovery, and reducing operational costs. 1. NOx JFE t/d Table 1 Fig t/d 3.2 m 6.2 m 8. m C 44

2 Exhaust gas recirculation system Oil burner Air Cooling air draft fan Cooling air Exhaust gas recirculated draft fan Lime, Activated carbon, CO, NOx sampling High-temperature gas generator Primary combustion chamber Municipal solid waste Boiler Dioxins sampling Cooling tower * 1 Bag house Induced draft fan Stack Secondary Steam turbogenerator Fire grate Primary * 1 Secondary Ash treatment furnace Oil burner Fig. 1 Schematic fl ow of the commercial plant with an advanced stoker system Plant NOx Table 1 Specifi cations of the commercial plant Incineration type Throughput Flue gas cooling Flue gas treatment Heat utilization Numanohata Clean Center Tomakomai City JFE Hyper stoker-type incinerator 15 t/d 2 lines Heat recovery boiler (2.8 MPa, 3 C) and cooling tower Bag house with lime and activated carbon supply Steam turbine (2.6 MPa, 295 C) and generator (2 kw) 1 C GAH SAH 25 C 2 O2 3 ACC λ C CO NOx O2 Fig C CO NOx 43.9 ppm 4 ACC CO Fig. 3 CO ppm 45

3 CO conc., NOx conc. at stack (ppm at 12% ) : ppm CO CO 5 ppm CO O2 O2 CO Table 2 3 TR A Steam (ACC set up 15 t/h) 16: 18: (Average 4.8%) NOx (Average 43.9 ppm) CO (Average 2.6 ppm) Time : 22: conc. at boiler outlet (%) Steam (t/h) Fig. 2 Changes in O2, CO2, and NOx in fl ue gas and steam with time CO (ppm) (λ 1.3) Conventional (λ 1.6) Mixing chamber Boiler inlet Boiler 2 path Boiler outlet Measured place Fig. 3 CO concentration in boiler Fig. 4 4 kg/h Unit weight Item Table 2 Slag properties (kg/l) Dry density (g/cm 3 ) Absorption ratio (%) Metallic iron (%) Size distribution percentage passing Leaching test (mg/l) 4.75 mm 2.36 mm.75 mm Cd Pb Cr 6 As Total Hg Se 8 MJ/ -t 3.3 Result Regulation TR A 17 FM Table 3 Heavy metal contents in slag * The Soil Pollution Control Law Invested energy (MJ/slag-t) Element Cd Pb Cr 6 As Total Hg Se Cyanogen F B Result Content (mg/kg) Regulation* Melting slag throughtput (kg/h) Fig. 4 Relationship between slag throughput and invested energy Table 4 ACC.78 ng-teq/nm µg-teq/ -t JFE No

4 Table 4 Dioxin emissions Flue gas at boiler outlet Flue gas at stack Fly ash Fly ash (De-dioxins) Melting slag Unsuitable for melting Total ( After fly ash de-dioxins treatment) Waste throughtput Flow/Feed rate Dioxins concentration Amount of dioxins 3 Nm 3 /h 34.2 kg/h (34.2 kg/h) kg/h 39 kg/h 4.27 t/h.17 ng-teq/nm ng-teq/nm 3.18 ng-teq/g (.1 ng-teq/g) N.D.. 5 ng-teq/g Amount of dioxins per waste throughput ( After fly ash de-dioxins treatment) 3 ng-teq/h ng-teq/h (342 ng-teq/h) ng-teq/h ng-teq/h ng-teq/h (365 ng-teq/h) 1.45 µg-teq/t-waste (.9 µg-teq/t-waste).1 ng-teq/g.9 µg-teq/ -t 3.4 Fig MJ/h Table 5 25 C Steam (kg/h) Conventional with ash treatment 13.4 t/h conventional 1 37 Mcal/h 15.2 t/h 14.6 t/h Low excess air combustion 9% increase Total input energy (Mcal/h) Low excess air combustion with ash treatment 13% increase Note: Heat value of kerosene for manufacturing the high-temperature mixed gas is included, but that of kerosene for ash treatment is not included. Fig. 5 Relationship between total energy input and steam recovery Energy resource Gas temperature Burner Steam heating * Average of day price and night price: 6.8 yen/kwh ** Price: 37 yen/l Table 5 Economic estimation ( C) Conventional combustion Test result Oil burner SAH Design standard for new plant Oil burner Steam recovery (t/h) SAH Increased steam recovery (t/h) Oil (kerosene) consumption 25 (l/h) l Preheating (t/h) Increased sales of electricity* (yen/h) Oil (kerosene) expense** (yen/h) Profit (yen/d) JFE No

5 Energy recovered by cooling water (kw) Conventional combustion Input energy of refuse (kw) Fig. 6 Tendency of heat load to the grate No C C Fig. 6 2, 15 JFE 21 1 NEDO NEDO NEDO JFE no. 3 4 p NKK no p JFE 21 48