Hydroprocessing

1
Hydroprocessing

• Hydrocracking
• (Hydrogenolysis, Hydrorefining)
• decrease MW and boiling point
• saturates from aromatics
• molecular size reduction
• resid upgrading

• Hydrogenation
• increase H/C (saturation of olefins aromatics)
• stabilizing distillate fuels like gasoline, jet
  fuel by preventing sediment formation
• upgrading (decreasing boiling pt. range) of
  residue

• Hydrotreating
• remove heteroatoms (S, N, metals)
• e.g., sweetening
• removal of impurities

2
Hydrogenation
Catalysts Pt, Pd, Ni on supports (SiO2,
Al2O3) (hydrogen addition)
3
Hydrocracking
2H2
H2
2H2
2H2
4
Hydrocracking

• Hydrocracking has a dual function
  (bi-functional) catalysts
• metals acid supports
• to perform two functions

Hydrocracking Catalysts
Cracking (acid support) SiO2 Al2O3 Al2O3 Low
zeolite SiO2 Al2O3 High zeolite SiO2 Al2O3
Hydrogenation Noble Pt, Pd Non-noble Ni, Mo,
Co, W
- susceptible to S poisoning
- Sulfided forms (MxSy) for high sulfur feeds
5
Hydrotreatment
Hydrodesulfurization (HDS)
6
Hydrotreatment
Hydrodesulfurization (contd)
Catalysts Sulfided Mo/AlO3 Co is used as a
promoter MxMo6S8
7
Hydrotreatment
This compound is very stable and it is very
difficult to remove the S atom because of steric
hindrance by methyl groups . Other isomers of
this compound are more reactive
Reactivity in HDS (k methylated DBT/
k DBT) 1) 4,6 DBT 0.1 2) 3,7
DBT 1.5 3) 2,8 DBT 2.6 4) 6-methyl-
dibenzothiophene 0.16
8
Hydrotreatment

• Hydrodenitrogenation (HDN)
• reduce fuel Nox upon combustion
• basic N poisons acidic catalysts

Catalysts Mo (or W) / Al2O3 / Ni
as promoter
9
Hydrotreatment

• Hydrodemetalation (HDM)
• metals poison catalysst
• metals are toxic, cause corrosion
• removes principally Ni, V

H - M - porphyrins
Catalysts used Mo/Al2O3
Co and Ni as promoters