This document discusses secondary reforming in ammonia and hydrogen/syngas production. It explains that ammonia plants commonly use a secondary reformer fired with air, as the nitrogen from air is useful for ammonia synthesis. However, hydrogen/syngas plants less commonly use secondary reforming because nitrogen cannot be tolerated in the process and an air separation unit may not be available or affordable to provide oxygen. The document outlines the key components of secondary reformers - the burner design, mixing volume, and catalyst - which must all be optimized to improve performance.

1. Ammonia
Secondary Reforming
Flowsheet
By:
Gerard B. Hawkins
Managing Director

2. Steam Reforming Section -
Options
H/C
feed
Pre-
reformer
Converts to
H2, CO, CO2 +
H2O + CH4
Secondary
reformer
Drives CH4
slip down +
other fact0rs
H2O
Steam
reformer
Converts to
H2, CO, CO2 +
H2O + CH4
H2O Air or O2

3. Steam Reforming Section - Secondary
Reformer
To Waste
Heat BoilerProcess
Steam
Hydrocarbon
Feed
HDS
Fuel
Steam
Generation
and
Superheating
Combustion
Air
Pre-heat
Air/Oxygen

4. Steam Reforming Section – Secondary
Reformer Introduction
 Three key components
• Burner Design
• Mixing Volume
• Catalyst
 All must be designed
correctly to maximize
performance
Air/Oxygen
Steam Reformer
Effluent
To Waste
Heat Boiler

5. Steam Reforming Section – Secondary
Reformer: Ammonia
 Ammonia plants fire the burner with AIR
• Adds O2 AND N2
 N2 is inert in secondary (more or less) &
through shifts/CO2 removal/methanation
 N2/H2 + residual CH4 go to
• Compression & NH3 synthesis loop
 Burner air provides the N2 required for NH3
synthesis
 Thus – secondary's are common in NH3
plants

6. Steam Reforming Section – Secondary
Reformer: Ammonia
 Most ammonia flowsheets
Ammonia
synthesis NH3
Converts N2 +
H2 => NH3
Syngas
compression
Air = O2 + N2
Secondary
reformer

7. Steam Reforming Section –
Secondary Reformer: Ammonia
 Linde LAC flowsheets
Ammonia
synthesis NH3
Converts N2 +
H2 => NH3
Syngas
compression
N2 from ASU
Secondary
reformer

8. Steam Reforming Section – Secondary
Reformer: H2/HyCO/MeOH
 H2/HyCO/MeOH plants must fire with O2
• N2 is not required in the process
• N2 cannot be tolerated in the process
 Source of O2 required
• Local air separation unit (ASU) may not be
available
• Over-the-fence from industrial gas company may
be expensive
• Construction/operation of ASU adds cost &
complexity
 THUS - O2 fired secondary's are less common