Abstract
Reactivities of various reduced crudes for hydrodenitrogenation
(HDN) were studied with a micro reactor. The feedstocks used are Arabian Light reduced crude (AL-RC), Kuwait reduced crude (KW-RC), Gach Saran reduced crude (GS-RC), Taching reduced crude (TA-RC) and Shengli reduced crude (SH-RC). The properties of these feedstocks are shown in Table 1.
All the micro reactor tests were carried out for 1 month with the Ni-Mo-Al2O3-B2O3 catalyst, the properties of which are shown in Table 2, under the same reaction conditions, i.e., reaction temp. 400°C, press. 140kg/cm2•G, LHSV 0.5hr-1, hydrogen to feedstock volume ratio 2, 000Nl/l. The results of HDN and HDS of various crudes are given in Figs. 1 and 2 respectively. The degree of activity decay is summarized in Table 3 and it seems to be almost the same for each feedstock. The order of HDN reactivity is AL-RC>KW-RC≈ GS-RC>TA-RC>SH-RC, which is equal to the HDS reactivity.
The HDN selectivities of the feedstocks varied in the range from 0.07 to 0.10 and they remained constant throughout the run except GS-RC (Fig. 3). Δ(H/C) was inversely proportional to the ratio of H to C of the feedstock (Fig. 4), on which the hydrogen consumption mainly depended (Fig. 5).
The results of fractional analysis (191-343°C, 343-538°C, 538°C+DAO, and asphaltenes) and used catalyst analysis are shown in Tables 4, 5 and 7 from which differences could be observed among the feedstocks.
Conversion of residual oils was calculated (Table 6) based on the Eqs. (1) and (2). Conversion of the Middle East feedstocks was higher than that of the Chinese feedstocks.
The degree of Nitrogen removal of the 3 fractions, except asphaltenes, was nearly equal, however, differed from the HDS, and these observations were confirmed by calculating the degree of nitrogen removal (Eqs. (3), (4), (5), and (6)) on the assumption that fractional transfer (cracking) would occur prior to the HDN reaction (Table 8). Some factors that affect the HDN reactivity were discussed.
