Page 204 - Energy from Toxic Organic Waste for Heat and Power Generation

182 Energy from Toxic Organic Waste for Heat and Power Generation

Speed: 1500 RPM, CR: 17.5
Inj.timing: 27 bTDC, Biomass: Babul wood
Injector: For diesel 3 hole, 0.2mm, for HOME 4hole, 0.3 mm
80 IOP: For diesel 205 bar, for HOME 230 bar
Carburetor: Parallel flow gas entry
Smoke opacity (HSU) 40 Diesel-PG (HCC)
60

HOME-PG (HCC)
20
HOME+FO10-PG (RCC)
HOME+FO20-PG (RCC)
HOME+FO30-PG (RCC)
0
0.00 0.74 1.48 2.22 2.96 3.70
Brake power (kW)
Fig. 11.22 Effect of combustion chamber shape and fuel oil addition on smoke opacity.

With combustion advancing, RCC geometry extends combustion areas and
widens combustion that leads to better utilization of oxygen during com-
bustion of fuel leading to better oxidation. Further marginal increase in delay
period compared to diesel-PG resulted in a more uniform mixture. Thus,
smoke levels decreased with use of fuel oil in the blends and RCC provision
[13]. Further, improved air-fuel mixing and better air utilization caused by
the optimum turbulence in the combustion chamber may also be the reason
for the results. However, too high fraction (more than 20% by vol) of fuel
oil in the blend during dual fuel operation increases the smoke levels in the
exhaust due to improper combustion of HOME caused by the reduction in
reaction rates between the fuel combinations. With HOME+FO-PG op-
eration, increased turbulent kinetic energy enabled by RCC occurs when
compared to HCC and is also responsible for this trend. However, literatures
suggest that narrow width has a higher unburned fuel-air mixture region,
and thus, would have higher smoke emissions. But with slightly wider com-
bustion chamber, lower smoke levels can be obtained [21–23]. The smoke
levels for HOME-PG (HCC) and HOME-PG (RCC) operation with 10%,
20%, and 30% fuel oil were found to be 68, 63, 61 HSU and 55 HSU, respec-
tively, compared to 43 HSU for diesel-PG operation (HCC).
Figs. 11.23 and 11.24 present the variation of hydrocarbon (HC)
and carbon monoxide (CO) with brake power. Dual fuel operation with
same combustion chamber shapes fueled with diesel-PG (HCC) combi-
nation always showed decreased HC and CO levels compared to other
fuel combinations tested. It could be due to incomplete combustion of