Page 165 - Advances in Eco-Fuels for a Sustainable Environment

136 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 60% 260 280 300 320 340
65%
Temperature (°C) Temperature (°C)
70%
75%
Microwave pyrolysis with stirrer speed 10 rpm 80% 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. 5.7 Comparison pyrolysis liquid yield for electrical and microwave pyrolysis.

of 3 L/min, the yield of pyrolysis oil had decreased. This is because the retention time
of the pyrolysis gases in a condenser was reduced beyond an optimum (i.e., 3L/min)
nitrogen flow rate. An increase in stirrer speed further increased the amount of local-
ized heat generation as well as the kinetic energy of the gases, which reduced the
amount of sufficient retention time, hindering the process of condensation. This led
to the decrease in the amount of the pyrolysis oil yield. Moreover, a broad range of
optimum pyrolysis oil yield was observed at a 10rpm stirrer speed.
The pyrolysis oil yield obtained in microwave pyrolysis was high when compared
with electrical pyrolysis at 10rpm stirrer speed. The maximum amount of oil yield was
obtained at 350°C temperature and a 3L/min nitrogen flow rate in microwave pyrol-
ysis. At 20rpm stirrer speed, improved oil yield was observed in electrical pyrolysis
when compared to microwave pyrolysis, due to a very high amount of localized heat
generation happening in microwave pyrolysis due to the insufficient retention rate.
The broad area of the optimum range was observed and is shown in Fig. 5.7.