Oleochemicals - What are they?
fatty acids
fatty alcohols
fatty methyl esters
fatty amines
glycerine
Oleochemical pathways
What are they used for?
Where do they come from?
Review of Organic Functional Groups
Fatty Acids
- Uses
- Process
- Splitting
- Hydrogenation
Ni Catalyst for FA hydrogenation
Catalyst deactivation in fatty acids by corrosion
Ni soap decomposition
Nickel dissolution in the presence of hydrogen
Comparison pore size & TG/FA molecules
Effect of pore dimensions in fatty acid hardening
Effect of premixing timeon catalyst activity
Effects of catalyst dissolution summarized:
Reducing Ni soaps
Issues
Alternative catalyst for FA hydrogenation (i)
Precious metal catalyst cycle
Alternative catalyst for FA hydrogenation (ii)
Fatty Alcohols
- Uses
- Process
Fatty Ester Hydrogenolysis
Fixed Bed Hydrogenolysis
Slurry Phase Hydrogenolysis
Fatty OH polishing
Fatty Methyl Esters
- Uses
Advantages of ME vs FA as a feedstock
FME - Biodiesel
Fatty Amines
Glycerin
- Uses
- The Future
REFERENCE:
Some graphs and photographs, in particular the photo of "The nickel deposits in the tube section", were extracted from Johnson Matthey contributions to International conferences.
5. • Palm Oil (PO)- Primarily derived from the palm oil plantations
in Malaysia and Indonesia is the major feedstock in Asia.
• Coconut - Major source Philippines. Declining in use.
• Fish oil (FH) - Predominantly used in Chile/Peru.
Was popular in UK, Norway, Japan.
• Canola/Rapeseed - Predominantly grown in Canada and
northern Europe. Typically has higher poisons than soya.
• Soyabean Oil (SO)- Primarily derived from the
major soya states in the US, Brazil and Argentina.
• Tallow - animal fat, usually a by-product of
rendering. Lard from pigs also used.
Where do they come from?
• Whales - major source of oleochemicals for
many years - oils, waxes, ester, spermaceti,
squaleen. No longer available due to over-
hunting
9. Different Process
◦ Twitchell
used catalyst
◦ Continuos
Colgate-Emery higher T & P than Twitchell
◦ Enzymatic
lipases
limited interest to date
10. Usually to full saturatiuon
◦ i.e. break all double bonds
Catalysts used
◦ Ni on silica powder; slurry phase
◦ Pd on C powder; slurry phase
◦ Pd on C; fixed bed
Reactor systems
◦ Batch Dead End reactors
◦ Continuous Plug flow continuous reactors
◦ Loop reactors
◦ typical conditions 200°C & 20bar
11. Typically a 22-25% Ni on silica or kieselguhr
support
Used by the majority of the market
Particle diameter 6-14 microns
Narrow pores to prevent Ni dissolution
Used once and then must be discarded
Dissolved Ni soaps end up in distillate residues
12. Equilibrium is determined by hydrogen concentration !
Ni(fa)2 + H2
low pressure/
hydrogen shortage
high pressure/
abundance of hydrogen
Ni + 2 ffa
13. Fate of nickel crystallites:
Nickel dissolution is chemically reversible, but catalytic
surface vanishes drastically thereby (loss of Nickel
dispersion):
+ ffa
- ffa
+ Ni-soaps
fresh
catalyst 100 m²/g Ni
used
catalyst 10-20 m²/g Ni
14.
15. 0
5
10
15
20
25
0 0.1 0.2 0.3 0.4 0.5 0.6
1/H2 pressure (bar-1)
DissolvedNi(ppm)
2 bar10 bar30 bar
Ni2+ = K.(H+)2/H2
Ni + 2H+ = Ni2+ + H2
Note Ni dissolution decreases by factor 100 for every pH unit rise!
(data based on fatty acid hydrogenation 180 C)
16. Smaller pore sizes impede diffusion of larger
molecules, i.e. triglycerides (Gly(fa)3) or nickel
soaps (Ni(fa)2)
17. Soybean soap stock fatty acids, 15 bar, 200°C
1
10
100
1 10
pore size diameter (nm)
final iodine
value
presumable
course
19. Loss of Nickel dispersion
Nickel soap formation
Residual Nickel in final product
20. Minimize contact time in absence of hydrogen
◦ Dose Ni to reactor just before addition of H2 or when it is
already under H2 pressure
◦ Filter catalyst from FA as quickly as possible
If melting of catalyst pellets required, melt in
triglyceride
22. Pd/C slurry phase
Typical 5% Pd on a carbon support
Can be re-used
Must have very efficient recovery
Current Pd price - $737/ounce
Financial management as important as
operational management
24. Pd/C fixed bed
Extrudates / Gauze
High working capital use
Efficient, continuous
production
Ni fixed bed has proved
difficult (basic supports,
posion resistance)
IV < 1
unsat FA
26. “Natural” fatty alcohols
◦ Hydrogenation (hydrogenolysis) of fatty methyl esters
◦ direct hydrogenation of fatty acids
Synthetic fatty alcohols
◦ Oxo-Alcohols
◦ Ziegler process
27. Catalysts used:
◦ CuCr
◦ CuZn
◦ CuSi
◦ Raney Cu
Fixed bed and slurry phase units in operation
Move to eliminate Cr
28. Feed: methyl esters
Gas phase FB
◦ 2900-3600psi; 230-250°C
Trickle-bed
◦ 2900-4350psi; 250 °C
29. Higher cat consumption than FB
Greater flexibility
Vertical plug-flow reactor
◦ 3600psi; 250-300°C
Direct hydrogenolysis of fatty acids (Lurgi)
◦ Acid-resistant catalyst required
◦ Excess of fatty OH and loop employed
◦ 4350psi; 300°C
30. Carbonyls in fatty OH can give unwanted
color, odor, etc
Can be removed by hydrogenation with Ni
◦ e.g. fixed bed process with PRICAT HTC
Ni impregnated alumina trilobe extrudate
◦ 100-150°C; 20-50bar
32. Usually manufactured directly from oils via
methanolysis with alkaline catalysts (e.g.
sodium methylate)
CH2OH
CHOH
CH2OH
3CHOH 3RCOOCH3
RCOOCH2
RCOOCH
RCOOCH2
NaOCH3
+ +
methyl ester
33. Lower energy consumption
Less corrosive -> less expensive equipment
More concentrated glycerine
Easier to distill
Superiority in some reactions
However the use of MeOH can have its
downsides
34. 3-armed high viscosity molecule broken down to
single chain low viscous fuel
Similar to cetane (C16)
• Growth industry due to:
– green movement and agricultural incentives in Europe
– agricultural lobby and aim for domestic fuel production in
USA
cetane (C16)
biodiesel
35. Most uses depend on the cationic nature of the amine
Fatty
Amines
Corrosion
Inhibitors
Fabric
Softeners
Lubricant
Additive
Organoclays
Sanitizing
Agents
H
H
NR
39. Batch slurry phase most common
Fixed bed or continuous slurry phase also used
Product Temp (C)
Pressure
(bar)
Catalysts Special Conditions
Primary 80-150 10-550
nickel, raney
nickel, cobalt
Ammonia added to feed to suppress
secondary and tertiary amine formation
Secondary 150-200 50-200 nickel, cobalt Ammonia removed by purging with hydrogen
Tertiary 160-230 7 - 14 nickel, cobalt
Secondary Amine used as feed; hydrogen
purge necessary to remove ammonia
Unsaturated
copper
chromite,
nickel
powder
similar to abovesimilar to above
47. Tertiary amine formation
proceeds via the same route as
with the secondary amine
formation. However, secondary
amine condenses with imine to
yield tertiary intermediates.
48. By-product during manufacture of
◦ fatty acid
◦ methyl esters & bio-diesel
◦ fatty alcohols
Also synthetic manufacturing
Supply-Demand balance always difficult
What to do with it all?
50. Supply will increase
◦ increasing production of biodiesel and use of oils and fats
as industrial feedstock
New demands must be found/created
◦ some of these may involve catalytic processes
◦ e.g. glycerine to glyceric acid over gold catalyst