Application of High Purity P. moriformis Microalgal Oil as Fuel for Diesel Engine
Purpose: the current status of examination of Diesel engines running on algal oils is in a state of flux. An extensive and systematic literature search was done showing that over the period of 2000 to 2017, only the oils obtained from three different species of algae, namely Tetraselmis suecica, Botryococcus braunii, and Chlorella protothecoides were evaluated as fuels for compression ignition (CI) engines through the extensive bench tests. Therefore, the development of alternative fuels particularly algae-derived oils needs further investigation. Methodology/approach: an experimental study was conducted on a 1Z-type internal combustion engine (ICE) running on the low load (Pe=60 Nm), average load (Pe=90 Nm) and high load (Pe=120 Nm) modes (n=const.=2000 rev-1) and using Diesel fuel (DF), high purity P. moriformis microalgal oil (PMO) and their 30% and 70% blends (PMO30; PMO70) as fuel. Variation of seven parameters, namely Brake specific fuel consumption (BSFC, g/kWh), Net efficiency (Ne), Exhaust gas temperature (exhT, K), Carbon dioxide (CO2, %), Hydrocarbon (HC, ppm), Nitrogen oxides (NOx, %) and Smoke (m-1) emissions were a target of research on the effect of performance appraisal of the CI engine. The received data for pure DF during engine bench testing at Pe=60; 90; 120 Nm has been assumed as a reference (100%) for the comparison with PMO30, PMO70 and PMO. Accordingly, following results for DF have been obtained: (i) Pe=60 Nm: BSFC (272.119 g/kWh), Ne (0.316), exhT (649 K), CO2 (5.271%), HC (7.443 ppm), NOx (309.429 ppm), Smoke (0.086 m-1); (ii) Pe=90 Nm: BSFC (255.267 g/kWh), Ne (0.344), exhT (724.286 K), CO2 (6.936%), HC (7.329 ppm), NOx (480.571ppm), Smoke (0.098 m-1); and (iii) Pe=120 Nm: BSFC (243.710 g/kWh), Ne (0.357), exhT (779.571 K), CO2 (8.371%), HC (7.214ppm), NOx (629.714 ppm), Smoke (0.107 m-1). Findings: following tendencies have been observed for 1Z-type engine operating on oxygenated fuels in comparison to DF, at Pe=60 Nm: (i) PMO30 (BSFC (+1.03%), Ne (+3.29%), exhT (+1%), CO2 (+2.34%), HC (+6.70%), NOx (+0.35%), Smoke (–17.50%)), (ii) PMO70 (BSFC (+7.50%), Ne (+6.65%), exhT (+2%), CO2 (+5.15%), HC (+17.85%), NOx (+1.15%), Smoke (–26.67%)), (iii) PMO (BSFC (+10.43%), Ne (+12.11%), exhT (+2.29%), CO2 (+6.87%), HC (+22.04%), NOx (+1.26%), Smoke (–28.83%)). For Pe=90 Nm: PMO30 (BSFC (–0.35%), Ne (+2.56%), exhT (+0.83%), CO2 (+1.81%), HC (+6.98%), NOx (+1.31%), Smoke (–25.00%)), (ii) PMO70 (BSFC (+6.58%), Ne (+5.35%), exhT (+1.84%), CO2 (+4.68%), HC (+8.97%), NOx (+1.63%), Smoke (–33.92%)), (iii) PMO (BSFC (+12.37%), Ne (+7.89%), exhT (+2.12%), CO2 (+5.25%), HC (+10.30%), NOx (+1.68%), Smoke (–37.91%)). And for the Pe=120 Nm: (i) PMO30 (BSFC (+2.60%), Ne (+0.65%), exhT (+1.10%), CO2 (+2.30%), HC (+7.13%), NOx (+2.18%), Smoke (–20.27%)), (ii) PMO70 (BSFC (+8.24%), Ne (+4.81%), exhT (+1.39%), CO2 (+3.84%), HC (+9.11%), NOx (+2.72%), Smoke (–37.47%)), (iii) PMO (BSFC (+12.70%), Ne (+8.70%), exhT (+1.64%), CO2 (+5.12%), HC (+14.36%), NOx (+2.90%), Smoke (–41.51%)). Originality/value: this study is a part of larger scale investigation done by authors on numerous synergistic improvements in cultivation of microalgae P. moriformis in humid climate countries as well as on production and appraisal of algal biofuels.