Reduction and Start Up of Pre-reforming

Catalyst

Gerard B. Hawkins Managing Director

Prereformer Startup

Drying Heating Startup Reduction

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

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

Catalyst Heating continued

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

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

Catalyst Heating continued

Holding at temperature Not recommended 2% hydrogen added Temperature reduced to 350°C

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

Condensation Ensure steam lines warm and low points

drained

Pre-reformer Cold Pipework

Steam

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

Reduction of Unreduced Catalyst

Unreduced catalyst As supplied - NiO on support Active species - Ni Crystallites Reduction process needed:

NiO + H2 Ni + H2O

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

Reduction of Catalyst continued

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

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

Pre-reformer Installation

Pre- Heating

Re- Heating

Gas/Steam

Pre-reformer

500ºC

500ºC 450ºC

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

Pre-reformer Installation

GBHE / HAISO– Technology Supplier

Axial flow with 2 Thermowells 6m3 bed of Catalyst

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

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