Hydrotreating of waste cooking oil for biodiesel production. Part II: Effect of temperature on hydrocarbon composition

This study focuses on the use of waste cooking oil (WCO) as the main feedstock for hydrotreatment to evaluate the effect of temperature on the product hydrocarbon composition. A qualitative analysis was initially performed using a GC × GC–TOFMS indicating the presence of mainly paraffins of the C15–C18 range. A quantitative analysis was also performed via a GC–FID, which gave both n-paraffins and iso-paraffins in the range of C8–C29. The results indicate that hydrotreating temperature favors isomerization reactions as the amount of n-paraffins decreases while the amount of iso-paraffins increases. For all experiments the same commercial hydrotreating catalyst was utilized, while the remaining operating parameters were constant (pressure = 1200 psig, LHSV = 1.0 h−1, H2/oil ratio = 4000 scfb, liquid feed = 0.33 ml/min, and gas feed = 0.4 scfh).