Conclusion and Future Scopes
11.1 Contribution of the Present Work
11.1.2 Standardisation of Operating Parameters for a Biogas Run Dual Fuel Engine The operating parameters namely, compression ratio (CR) and injection timing (IT), were
standardised on the basis performance and emission characteristic for a biogas run dual fuel diesel engine using three different types of pilot fuel. The pilot fuel includes diesel, RBB and emulsified RBB (WIRBB). The main findings of this study are discussed below
For Diesel Pilot Fuel:
The BTE of the biogas run dual engine is found to be increase with the use of high CR of 18. However, with the advancement of pilot fuel IT, the performance improves up to a particular IT. The maximum BTE of 25.44% is obtained for a combination of CR=18 and IT=29°BTDC.
At 23°BTDC with 100% load, the LFR is found to be 79.46%, 76.1%, 74% and 72%
for CRs of 18, 17.5, 17 and 16, respectively. For CRs of 18, 17.5, 17 and 16, the LFR is found to be 83.17%, 80.67%, 76.06% and 75.22%, respectively at 26° BTDC in comparison to 82.67%, 80.70%, 76.06 and 75.22% at 29° BTDC. However, at 32°
BTDC, the LFR is found to be 79.32%, 78.4%, 76.13% and 76.1% for CRs of 18, 17.5, 17 and 16, respectively.
On an average, there is an increase of 23.23% in CO2 emission on advancing IT from 23° to 32° BTDC for CR of 18. For the same range of IT, there is an increase of 18.18%, 15.37% and 14.97% in CO2 emission for CR of 17.5, 17 and 16, respectively.
Therefore, there is an increase of 27.18% in CO2 emission while increasing the CR from 16 to 18 at 23°BTDC.
There is a reduction of 26.22% in CO emission by increasing the CR from 16 to 18 at 23°BTDC. There is a reduction of 5.59% in CO emission on advancing IT from 23°
to 32° BTDC for CR of 18. For the same range of IT, there is a reduction of 6.56%, 8.64% and 10.7% in CO emission for CR of 17.5, 17 and 16, respectively.
There is a reduction of 41.97% in HC emission is achieved by increasing the CR from 16 to 18 at 23°BTDC. There is reduction of 9.54% in HC emission is achieved on advancing IT from 23°to 32° BTDC for CR of 18. For the same range of IT, on an average, there is a reduction of 10.03%, 13.83% and 8.98% in HC emission for CRs of 17.5, 17 and 16, respectively.
There is an increase of 38.81% in NOX emission is resulted by increasing the CR from 16 to 18 at 23°BTDC. there is an increase of 15.91% in emission is achieved on advancing IT from 23°BTDC to 32° BTDC for CR of 18. For the same range of IT, there is increase of 10.76%, 9.7% and 4.2% in NOX emission for CR of 17.5, 17 and 16, respectively.
For RBB Pilot Fuel:
The BTE of the RBB-biogas run dual engine is found to be increase with the use of high CR of 18. The performance improves further with the advancement of pilot fuel IT. The maximum BTE of 25.88% is obtained for a combination of CR=18 and IT=32°BTDC.
At 23° BTDC with 100% load, the LFR is found to be 80%, 79% and 78.26% for CRs of 18, 17.5 and 17, respectively. For the same loading conditions at CRs of 18, 17.5 and 17, the LFR is found to be 80%, 80% and 80.25% at 26°BTDC in comparison to 80.51%, 80.51% and 77.71% at 29°BTDC. However, the LFR is found to be 82.75%, 72.51% and 71% for CRs of 18, 17.5 and 17, respectively at 32°BTDC.
There is an average rise in CO2 emission by 13.78% on increasing the CR from 17 to 18 at 23°BTDC. Therefore, there is a rise of 17.43% in CO2 emission on advancing IT from 23°to 32°BTDC for CR of 18. For the same range of IT, on an average, there is
an increase of 17.14% and 12.21% in CO2 emission for CR of 17.5 and 17, respectively.
There is an average drop in CO emission by 17.67% on increasing the CR from 17 to 18 at 23°BTDC. There is a reduction of 11.64% in CO emission on advancing IT from 23° to 32°BTDC for CR of 18. For the same range of IT, on an average, there is a reduction of 6% and 3.38% in CO emission for CR of 17.5 and 17, respectively.
There is an average reduction in HC emission by 17.67% on increasing the CR from 17 to 18 at 23°BTDC. On an average, there is a reduction of 15.24% in HC emission is achieved on advancing IT from 23° to 32°BTDC for CR of 18 under DFM. For the same range of IT, on an average, there is a reduction of 13.14% and 14.27% in HC emission for CRs of 17.5 and 17, respectively.
There is an average increase in NOX emission by 42% on increasing the CR from 17 to 18 at 23° BTDC. There is an increase of 39% in emission is achieved on advancing IT from 23° to 32°BTDC for CR of 18 under DFM. For the same range of IT, there is a rise of 41.42% and 52.14% in NOX emission for CR of 17.5 and 17, respectively.
For Emulsified RBB Pilot Fuel:
A two-phase stable WIRBB emulsion was prepared in the laboratory using by optimizing the factors such as water content (5%and 10%), surfactants (3%), and hydrophilic lipophilic balance (HLB) values. The prepared WIRBB was then characterized by means of droplet diameter measurement and stability study. The results of this study are summarized as follows
The values of mean droplet diameter (1.64 µm for 5% water WIRBB) fall within the acceptable range of maximum (20 µm) and minimum (0.1 µm) values.
The longer the emulsification time, lower is the mean droplet diameter.
Higher the surfactant quantity, lower is the mean droplet diameter.
Increase in water quantity increases droplet size.
Larger water quantity increases separation and sedimentation.
The prepared WIRBB is tested as a pilot fuel in a biogas run dual fuel engine for a set of combinations of CRs and ITs at different loading conditions. The results of the analysis are discussed below
The BTE of the WIRBB-biogas run dual engine is found to be increase with the use of high CR of 18. The performance improves further with the advancement of pilot fuel IT. The maximum BTE of 23.62% is obtained for a combination of CR=18 and IT=29°BTDC.
At 23° BTDC with 100% load, the LFR is found to be 79.25%, 77.77% and 76.79%
for CRs of 18, 17.5 and 17, respectively. For the same loading conditions at CRs of 18, 17.5 and 17, the LFR is found to be 79.47%, 78.27% and 78.21% at 26° BTDC in comparison to 82.22%, 80.24% and 79.25% at 29° BTDC. However, the LFR is found to be 80.24%, 79.25% and 75.46% for CRs of 18, 17.5 and 17, respectively at 32° BTDC.
There is an average rise in CO2 emission by 24.45% on increasing the CR from 17 to 18 at 23°BTDC. Therefore, there is a rise of 13.76% in CO2 emission on advancing IT from 23°to 32°BTDC for CR of 18. For the same range of IT, on an average, there is an increase of 16.89% and 23.02% in CO2 emission for CR of 17.5 and 17, respectively.
There is an average drop in CO emission by 17.6% on increasing the CR from 17 to 18 at 23°BTDC. There is a reduction of 4.7% in CO emission on advancing IT from 23° to 32°BTDC for CR of 18. For the same range of IT, on an average, there is a reduction of 3.27% and 7.34% in CO emission for CR of 17.5 and 17, respectively.
There is an average reduction in HC emission by 32.8% on increasing the CR from 17 to 18 at 23°BTDC. On an average, there is a reduction of 6.23% in HC emission is achieved on advancing IT from 23° to 32°BTDC for CR of 18 under DFM. For the same range of IT, on an average, there is a reduction of 11.96% and 13.5% in HC emission for CRs of 17.5 and 17, respectively.
There is an average increase in NOX emission by 40.98% on increasing the CR from 17 to 18 at 23° BTDC. There is an increase of 16.26% in emission is achieved on
advancing IT from 23° to 32°BTDC for CR of 18 under DFM. For the same range of IT, there is a rise of 16% and 18.03% in NOX emission for CR of 17.5 and 17, respectively.