Table 9. Elemental Changes of Residual Oil before and after Reaction^a.

oil sample	before reaction	1#after reaction 1	1#after reaction 2	2#after reaction 3	3#after reaction 4
temperature/°C		280	310	340	340
pressure/MPa		3	3	3	3
amount of catalyst/wt %		2.2	2.2	3	1
time/h		24	1	2	2
oil–water ratio		7:3	7:3	10:3	10:3
NH/NC	1.39	1.42	1.40	1.64	1.64
N	0.81	0.8	0.8	0.75	0.78
S	1.82	1.70	1.78	0.91	0.9

^aNote: 1# is nonemulsified residual oil, 2# is emulsified residual oil with 0.5 wt % sodium oleate and 0.5 wt % n-butanol, and 3# is emulsified residual oil with 1 wt % sodium oleate and 0.5 wt % n-butanol.