ISSN 2086-5953
2 MODEL, ANALYSIS, DESIGN,
AND IMPLEMENTATION
2.1 Laboratory Melting System
The melting system consists of a high- temperature furnace, a secondary combustion
chamber, and one set of APCDs including a cooling unit collects the condensed water of the volatile
gas, a filter collects particles, and three-stage glass PUF cartridge adsorption collects the
gaseous phase compound as illustrated in Figure 1. The specifications of the melting system are as
follows. The high-temperature furnace has a width of 210 mm, a length of 280 mm, and a height of
220 mm, with a maximum temperature of 1600 °C, and the heat loading is 6.6 kW. The furnace has an
inner graphite crucible, and on top of this crucible is a cone-shaped cap hood for collecting volatile
gases. The volatile gases collected by the cap hood will be delivered with an Al
2
O
3
tube to the secondary
combustion chamber
for further
combustion or introduced to the APCDs. The secondary combustion chamber has an inside
diameter of 50 mm and a length of 1000 mm, with a maximum temperature of 1300 °C, and the heat
loading is 6.6 kW. The flue gas cooling unit with indirect water cooling has an inside diameter of 25
mm and a length of 1700 mm. The diameter of the filter is 51 mm, and each stage of the three-stage
PUF cartridge adsorption has a length of 130 mm. Three separate tests were performed by measuring
PBDE in the third stage of the PUF cartridge to ensure the gaseous PBDE are insignificant, , and
less than 2 PBDE mass was found at the third stage of the PUF cartridge. The waste flexible
PBDE were first cut into small pieces ca. 5 x 5 x 0.5 mm, and metals on the surface were stripped
off by aqua regia extraction. The waste PBDE was pretreated to prevent the metals from corroding the
equipment. The concentrations of Al, Cu, Ni, and Au in the extraction solution were analyzed with
the same ICP-AES instrument. When the metals were stripped off the surface of the waste PBDE by
the aqua regia solution, the concentration of metals was reduced by 75-95 and the weight of the
PBDE reduced by approximately 25. The experimental sample placed inside a graphite
crucible was put in the furnace; the furnace temperature was than increased to 850 or 1450 °C
at 6 °C min
-1
held for 30 min, with the secondary combustion chamber at 900 °C. The pump rate for
withdrawing gaseous samples was 10 L min
-1
. The batch experiment was repeated twice. After the
pyrolysis process, the bottom ash, fly ash, and cartridge were collected and analyzed to determine
the concentrations of PBDE on the basis of the National Environment Analysis Method NIEA
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