Effect of phospholipids on the premixed combustion behavior of Jatropha curcas biodiesel

Excessive phosphorus content in biodiesel is one of the main reasons that aggravate the formation and emission of particulate matter during combustion, which easily deteriorates the catalytic conversion performance of automobile exhaust and makes it difficult to control pollutant emission. At present, the influence mechanism of phosphorus in biodiesel on the combustion process is not clear. To this end, in this study, thermogravimetry-differential scanning calorimetry (TG-DSC), mass spectrometry (MS), flue gas analysis, transmission electron microscopy (TEM), and other experimental techniques are used to examine the flame characteristics and pollutant emission of Jatropha biodiesel (JB100) premixed combustion under different phospholipid (PE) contents. The results reveal that the increase in the PE content can reduce the pyrolysis reaction activation energy of JB100, and the reaction activation energy under 400 ppm PE is the lowest, which is 9.67% lower than that of JB100 without PE. At the same time, with the increase in the PE content, the soot production intensity is gradually enhanced, the production of C2 and CH radicals is gradually weakened, and the flame height decreases gradually. When 1000 ppm PE is added, the flame height decreases by 12.31% compared with that of JB100. As the addition amount of PE increases, the OH intensity of combustion flame initially increases and then decreases with the increase in the axial position of flame, and the peak OH intensity reaches the maximum at 400 ppm. Besides, with the increase in the PE content, the emitted concentration of CO and NOx gradually increases, the particulate emission first increases and then decreases, and the average diameter of soot particles becomes larger than that of JB100 (16.34 nm). When 400 ppm PE is added, the average particle size is the largest, which is 28.09% higher than that of JB100 without PE.