Page 167 - Advances in Eco-Fuels for a Sustainable Environment

138 Advances in Eco-Fuels for a Sustainable Environment

Electrical pyrolysis with stirrer speed 10 rpm Electrical pyrolysis with stirrer speed 20 rpm
5.0 5.0
4.5 4.5
Nitrogen flow rate (L/min) 3.5 Nitrogen flow rate (L/min) 3.5
4.0
4.0

3.0
3.0
2.5 2.5

2.0 2.0
260 280 300 320 340 10% 260 280 300 320 340
15%
Temperature (°C) Temperature (°C)
20%
25%
Microwave pyrolysis with stirrer speed 10 rpm 30% Microwave pyrolysis with stirrer speed 20 rpm
5.0 5.0
4.5 4.5
Nitrogen flow rate (L/min) 3.5 Nitrogen flow rate (L/min) 3.5
4.0
4.0

3.0
3.0
2.5 2.5

2.0 2.0
300 320 340 360 380 400 300 320 340 360 380 400
Temperature (°C) Temperature (°C)
Fig. 5.8 Comparison of noncondensable gas yield for electrical and microwave pyrolysis.

yield because of decreased deposition of char on the walls of the reactor vessel.
Increased deposition of char reduced the rate of heat transfer and promoted the for-
mation of char due to slow heating observed at 10rpm stirrer speed. Fig. 5.9 shows
the formation of char with different temperature and nitrogen flow rate for the elec-
trical and microwave pyrolysis.
The percentage of char formation in microwave pyrolysis was less compared to
electrical pyrolysis due to the higher localized heat generation, which was the primary
cause of decreased char formation. In this microwave region, the generation of local-
ized heat was increased and increased the temperature of the spots involving rich in
carbon. Carbon converts the energy of the microwaves into heat and finally evaporates
because of the high localized temperature. Thus, the yield of char formation was
reduced in microwave heating. Increased temperature and nitrogen flow rates
decreased the amount of char formation from 16% to 8% at 10rpm stirrer speed. How-
ever, at 20rpm stirrer speed, the nitrogen flow rate did not affect the yield of char with