Page 233 - Biofuels Refining and Performance

216 Chapter Seven

5000
Petrol
4000

NO X (ppm) 3000

2000

1000 Methanol

0.6 0.8 1.0 1.2 1.4 1.6
Equivalence ratio
Figure 7.19 Effect of equivalence ratio on NO x .

For all the above graphs, the engine details and compression ratio are
as follows:

1. Full throttle rpm 2500
2. Compression ratio
Methanol Petrol
R 9 R 9
c
c
R 12.6
c
Regarding emission, ethanol and methanol are considered as clean
fuels, as emissions of CO, HC, and NO are reduced by nearly 10–15%
x
compared with a petrol engine. The flame speed of alcohol mixtures is
higher than a petrol A:F mixture, and this helps in making the com-
bustion more complete without misfiring.
Regarding the production of formaldehyde, its percentage in exhaust
is much higher, which is a great problem to extract methanol in pure form

300
R = 8.5 & rpm = 2000
c
Methanol
Aldehydes (ppm) 200 Petrol

100

Figure 7.20 Effect of equivalence
0.7 0.8 0.9 1.0 1.1 1.2 1.3 ratio on aldehyde.
Equivalence ratio