Abstract
A mixture (Feed B) of 1 volume of Condor shale oil middle distillate (Feed A) and 1 volume of Arabian light middle distillate was hydrotreaded under various conditions in an attempt to clarify the relationships between product oils and reaction conditions. Using the same apparatus used in our previous work1), experiments were made in the presence of a NiO-MoO3-Al2O3 catalyst at temperatures ranging from 310 to 350°C, and hydrogen pressures ranging from 25 to 100kg/cm2 and under liquid hourly space velocity (LHSV) of 1hr-1.
The properties of Feed B and product oils are shown in Table 1. Sulfur and nitrogen were significantly removed with increasing reaction temperature and hydrogen pressure (Figs. 1 and 2). Because the percentage of sulfur removal of Feed B reached above 85% even under such mild conditions as 310°C and 25kg/cm2 hydrogen pressure, hydrodesulfurization would cause no problem in the refining of Feed B.
On the other hand, the nitrogen removal increased by 1.2-1.3 times that of Feed A under all conditions except 350°C and 100kg/cm2 hydrogen pressure, under which it was approximately 100%, indicating that nitrogen is removed more efficiently from a mixture of the shale oil and other oils containing a little nitrogen than from the shale oils itself. Apparent activation energies of nitrogen removal reaction on the NiO-MoO3-Al2O3 catalyst were 11.9, 22.4 and 33.7kcal/mol at 25, 50 and 100kg/cm2 respectively (Fig. 3) which were larger than those of Feed A.
Specific gravity and viscosity decreased with increasing reaction temperature and hydrogen pressure (Fig. 4), but the H/C atomic ratio, which was about 1.9, and distillation characteristics changed but little under these conditions. It is reasonable to consider that Feed B was not cracked markedly because of the low reaction temperatures involved.
