OCR Text |
Show 4. Operational Test 4.1 Outline of the Incineration Furnace Table 3 lists the specification of the incinerator. This plant was built about 1 5 years ago for the purpose of burning refuse with an average LHV of 1 ,000Kcallkg, raging 600",2,000Kcal/kg. The furnace consists of refuse feeder and drying-, combustion-, and burnout-grates. Preheated air is fed from underneath the grates, and cooling air is supplied near the combustion chamber exit. The exhaust gas is cooled at the boiler down to 650':'C", 700':'C, and a part of it is utitized for preheating air, while the rest is cooled below 300';'C by means of water spray. It then goes through dry scrubber for HCe removal and electrostatic precipitator for particulate removal, and finally sent up the flue. Table 3 Specification of MSW Incineration Furnace MSW Throughput 7 5t124h x 2 Furnaces Type Takuma Stoker Furnace Width 1,950mm Heat Recovery Boiler + Water Injection Flue Gas Treatment Dry Lime Injection + ESP 4.2 Outline of Testing Equipment The Piping and Instrumentation Chart is shown on Figure 2. Because the city gas (natural gas) has not been piped into the area where the incinerator is located, liquefied natural gas in cylinders has been brought into the premises where it was gasified and used for the test. The volume of natural gas for reburning was less than 1 % of furnace exhaust gas. In order to obtain a even mixture, therefore, it was mixed before injection with the recirculating exhaust gas, the maximum volume of which was 20% of the total furnace exhaust. Stipulation was also made so that the natural gas/recirculating gas mixture could be injected either from the front, or the rear of the furnace. For this testing, a new secondary air fan has been added. This fan can supply secondary air independent of the under-grate air. Air nozzles have been installed at four locations; the front of the furnace, high and low at the rear, and on furnace side wall. Although cool air was intended for secondary air injection, a steam air-heater has been added so that experiments can be carried out at various air temperatures. Recirculating gas was taken out of the induced draft fan inlet, after the fly ash and HC{ had been removed. It was then pressurized by the recirculating fan, split into two passages so that each stream could be mixed with natural gas independently. 4 |