diesel hydrotreaters revamp a way for increasing production

44th International Petroleum Conference, Bratislava, Slovak Republic, September 21-22, 2009 4
RESULTS AND DISCUSSION
During the performance test of the HDS-3 unit the product (stable
hydrogenate) properties were as follows:
- Product properties
Sulphur , wt ppm ≤ 5
Density at 15 °C, kg/m 3 840.5-843.6
Polynuclear aromatics , % 4.6-5.8
These data indicate that the increase of the catalyst volume by a factor
of 1.9 (decreasing the LHSV from 1.7 to 0.90h -1 ) allowed the LNB heavy
middle distillate hydrotreater HDS-3 to produce NZSD. The hydrogen
consumption was found to be 28.3 Nm 3 /m 3 oil which was 8% higher than that
recorded before the reconstruction (26.3 Nm 3 /m 3 oil).
During the performance test of the HDS-2 unit the product (stable
hydrogenate) properties were as follows:
- Product properties
Sulphur , wt ppm ≤ 5
Density at 15 °C, kg/m 3 844-845
Polynuclear aromatics , % 4.6-5.8
These data indicate that the increase of the catalyst volume by a factor
of 1.7 (decreasing the LHSV from 2.0 to 1.17h -1 ) allowed the LNB heavy
middle distillate hydrotreater HDS-2 to produce NZSD. The hydrogen
consumption was found to be 34.2 Nm 3 /m 3 oil which was 14% higher than that
recorded before the reconstruction (30.1 Nm 3 /m 3 oil).
Figures 1 and 2 present the deactivation of the catalyst TK-576 Brim in
the LNB HDS-3 and HDS-2 heavy middle distillate hydrotreaters. It is evident
from these data that the catalyst in HDS-2 unit has exhibited higher
deactivation rate of 3.4 0 C/month, than HDS-3 catalyst whose deactivation rate
is 3.0 0 C/month. With a start of run temperature (SORT) of 350 0 C and end of
run temperature (EORT) of 390 0 C a cycle length of 13 months is obtained for
HDS-3. With a start of run temperature (SORT) of 349 0 C and end of run
temperature (EORT) of 390 0 C also a cycle length of 12 months is obtained for
HDS-2. The replacement of the older heat exchangers in both units not only
improved reliability but also improved the unit energy efficiency. The cost for
fuel gas was reduced by a factor of two.