Abstract
In the present study the applicability of hydrodesulfurization of a mixture of crude oil fractions (e.g., naphtha, kerosene, and gas oil ) in a single hydrotreating reactor packed with NiCoMo/Al2O3 under various operating parameters such as temperature (310-370 oC), pressure (40-55 bars), weight hour space velocity (1.2 to 3.6 h-1), and hydrogen-to- liquid hydrocarbon ratio (150-300 vol/vol). Experimental results showed that temperature and pressure have a positive effect on process performance while weight hour space velocity gives a different trend. The optimum value of (H2/Hydrocarbon) ratio was found experimentally to be 200 vol/vol after which the increase in this ratio cause reduction in HDS% because decrease in contact between H2 gas and Hydrocarbon in reactor. Results showed that the best conditions (350 oC, 50 bars, 1.2 h-1, and 200 vol/vol) in which gave the hydrotreating (HDS) efficiency of 95.8%.The results confirmed the applicability of the NiCoMo/Al2O3 catalyst for HDS reaction of a mixture of middle distillate (e.g., naphtha, kerosene, and gas oil). It was found that at higher pressure and temperature (i.e., T> 350 oC; P> 50 bars) a thermodynamic equilibrium was established. As observed, there is a 1.6% reduction in gas oil less than that of the conventional method. However, kerosene, heavy naphtha, and light naphtha undergo increases of 0.6%, 0.75%, and 2.75% respectively over these from conventional method. These results reveal that the quantity of fractions is almost the same for both methods. As it can be observed, that measured properties of the oil fractions produced by the proposed method are almost the same as those produced by conventional method. However, specific gravity (sp.gr) of the oil cuts produced by present study (i.e. sp.gr of kerosene, heavy naphtha, and light naphtha 0.785, 0.728, 0.655 respectively) is somewhat less than sp.gr of the same fractions produced by conventional methods (i.e. sp.gr of kerosene, heavy naphtha, and light naphtha 0.788, 0.738, 0.65 respectively), which gives a clear indication of properties improvement of these fractions. Experimental results confirmed the applicability of the proposed method for HDS of a mixture of Iraqi middle distillates (i.e., naphtha, kerosene, and gas oil) simultaneously in a single fixed bed reactor.
