Experimental evaluation of the effects of using diesel/biodiesel/C4 alcohol mixtures in a compression ignition engine on emission parameters

In this study, the %FFAs (Free Fatty Acids) value of the oil was found to be 1.579 mg KOH/g in terms of oleic acid, using the titration method, before the synthesis of safflower seed oil into biodiesel. Since this value is less than 3, it was synthesized into biodiesel with one-step base-catalyzed transesterification reaction. Various fuel properties of the biodiesel were determined using ASTM and EN standard methods, and accordingly discussed. The biodiesel synthesized from safflower seed oil meets both ASTM-D6751 and EN-14214 standards. The blending of alternative biofuels such as biodiesel (B100) and n-butanol into fossil diesel fuels (DF) at certain ratios in recent years, with the aim of controlling emissions such as nitrogen oxides (NOx), carbon monoxide (CO), and smoke, has drawn significant attention. Additionally, since biodiesel and alcohols fall into the aliphatic alcohol category and do not contain aromatic compounds (such as benzene and its derivatives) in their chemical structures, they offer potential additional advantages in reducing soot, particle, and toxic emissions, including polycyclic aromatic hydrocarbons (PAHs). However, studies in the literature have generally only been conducted with relatively low blend ratios (less than 20%). In this study, the effects on emissions of mixtures of DF, B100, and n-butanol were investigated. The emission values obtained were compared with the emission values of DF, B100, 50%/50% volume ratio diesel/biodiesel (DF50B50), 50%/50% volume ratio diesel/n-butanol (D50BU50), 50%/25%/25% volume ratio diesel/biodiesel/n-butanol (D50B25BU25), 50%/35%/15% volume ratio diesel/biodiesel/n-butanol (D50B35BU15), and 50%/45%/5% volume ratio diesel/biodiesel/n-butanol (D50B45BU5) blends. Among these blends, DF50B50 and DF50B25BU25 fuels reduced the smoke opacity (SO) by 80.17% and 72.73%, respectively, compared to pure DF under maximum load conditions. Under the same load conditions, DF50B50 and DF50B25BU25 fuels also reduced NOx emissions by 19.18% and 22.64%, respectively, compared to pure DF, while reducing CO emissions by 30% and 18.46%, respectively.