Drying Heating Startup Reduction

1. Reduction and Start Up
of Pre-reforming
Catalyst
Gerard B. Hawkins
Managing Director

2. Prereformer Startup
 Drying
 Heating
 Startup
 Reduction

3. Catalyst Drying
For catalyst subjected to low
temperatures
 Dry using Nitrogen
 175 to 250°C
 NG can be used below 200°C
 4 to 24 hours
 Dry air, not suitable for prereduced
 First startup of prereduced

4. Catalyst Heating
 Normally heated using nitrogen
 Absorbed moisture
 Initial heating rate, 50°C per hour
 Max temp differential in bed 100°C
 At 200°C, 70°C per hour
 Heating till peak 400°C, min 370°C
 High circ rate, max pd 2 bar

5. Catalyst Heatingcontinued
Warm-up rates
 Rapid warm-up minimises energy
usage/time
 Traditional constraints of equipment
 Controllability
 Limited by mechanical considerations of
vessel
 Catalyst, 150-170oC per hour

6. Catalyst Heating continued
Limits on impurities
 Oxygen 1% vol
 Carbon Dioxide 1% vol
 Carbon Monoxide 1% vol
 Methane 1% vol
 Hydrogen 1% vol
 Ethane 100 ppm vol
 Sulfur 0.2 ppm vol

7. Catalyst Heating continued
Holding at temperature
 Not recommended
 2% hydrogen added
 Temperature reduced to 350°C

8. Catalyst Startup
When operating temperature has been
achieved:
 Check for build up of carbon oxides
and hydrocarbons
 Add of 10% Hydrogen
 Followed by steam
 Introduce process feed, maintain safe
S:C

9. Condensation
 Ensure steam lines warm and low points
drained
Pre-reformer
Cold Pipework
Steam

10. Heating using Natural Gas
Using NG as heating medium
 No impurities
 Immediate startup
 50°C per hour, max differential 100°C
 At 200°C introduce steam
• Min S:C 0.3kg/kg at 200°C
• Min S:C 0.5kg/kg at 400°C to 450°C
• Increase to design feed and S:C

11. Reduction of Unreduced
Catalyst
Unreduced catalyst
 As supplied - NiO on support
 Active species - Ni Crystallites
 Reduction process needed:
NiO + H2 Ni + H2O

12. Reduction of Unreduced
Catalyst
Reduction aspects
 Bed temperature 450°C and 500°C
 12 to 16 hours
 Hydrogen must be
• free of poisons (S, Cl)
 Special consideration must be given to the
presence in impure hydrogen sources of
• carbon oxides
• hydrocarbons

13. Reduction of Catalystcontinued
Reduction procedure
 Hydrogen set at 15 –25%
 Slowly increased to 50%
 Regularly check hydrogen levels
 Water cooled and collected
Reduction complete
 85% of reduction water collected
 Consumption of hydrogen stopped

14. Pre-reformer Objectives
Remove the restriction on the ID Fan to
allow rate increase to Design MTPD
Improve efficiency by recovering
additional process heat from flue gas
 Pre-reformer aims:
• Reduce primary reformer firing
• Reduce flue gas temperature to ID fan
• 4 Year design life
• Install during next turnaround
• Maintain operating flexibility

15. Pre-reformer Installation
Pre-
Heating
Re-
Heating
Gas/Steam
Pre-reformer
500ºC
500ºC
450ºC

16. Pre-reformer Installation
 New Pre-Reformer
New Vessel and Piping
Integration with Flue Duct
By-pass Quench Arrangement
 Duct Modifications
New Coils
• Reheat Post Pre-reformer
• Cold’ Feed Pre-heater
• Natural Gas Pre-heater
• Process Air Pre-heater
• Superheater Coil
Existing Coils
• Check New Duty Performance

17. Pre-reformer Installation
 GBHE / HAISO– Technology
Supplier
 Axial flow with 2 Thermowells
 6m3 bed of Catalyst

18. Planned Procedure
•Commissioning smooth minimal changes to normal
plant start up
– Pre-reformer bypassed initially
– Quench controls primary inlet until production
achieved
– Process gas slowly introduced to pre-reformer
–As inlet exit valves fully open, by-pass closed
–Quench valve closed as endotherm takes place
•