Historical Development

Topsoe (formerly Haldor Topsøe) has been a pioneer in hydrogen production technology since 1940, with steam methane reforming (SMR) becoming the cornerstone of industrial hydrogen generation^[2]. The company's tubular reformer technology evolved from early developments in the 1940s to become the industry standard for large-scale hydrogen production. Plant capacities have grown from initial small-scale units to modern facilities exceeding 200,000 Nm³/h (200+ MMscfd)^[1][3][5].

Topsoe (formerly Haldor Topsoe) offers three principal process technologies for hydrogen production—SynCOR™, HTCR, and SMR—each suited to different plant capacities, feedstock flexibility, and project requirements^[6]:

• SynCOR™ (Autothermal Reforming): 
  • Best for: Mega-scale hydrogen plants (very large capacities), blue hydrogen projects with high carbon capture requirements, and integrated syngas production for ammonia, methanol, and synfuels.
  • Typical scale: >200,000 Nm³/h H₂ (world-scale, single-train plants).
     
• SMR (Steam Methane Reforming, Tubular Reformer):
  • Best for: Medium to large-scale hydrogen production, especially when maximum flexibility in feedstock and steam export is desired.
  • Typical scale: 15,000–200,000+ Nm³/h H₂.
     
• HTCR (Haldor Topsoe Convection Reformer):
  • Best for: Small to medium-scale hydrogen plants, modular projects, and revamps where plot space, fast installation, and high thermal efficiency are critical.
  • Typical scale: 5,000–50,000 Nm³/h H₂.

​​​This review focuses on SMR process for hydrogen production.  

Technology Overview

Topsøe's conventional SMR technology centers around the tubular reformer, a radiant wall steam reformer that converts hydrocarbon feedstocks into high-purity hydrogen. The tubular reformer operates as a side-fired or top-fired furnace containing catalyst-filled tubes where the primary reforming reactions occur.

Key technological features include:

• Radiant Wall Tubular Reformer: The heart of the process, operating at 800-950°C with advanced refractory linings
• Advanced Reforming Catalysts: Nickel-based formulations enabling low steam-to-carbon ratios
• High-Temperature Operation: Up to 950°C (1,740°F) outlet temperatures for maximum efficiency
• Feedstock Flexibility: Capable of processing natural gas, LPG, naphtha, and refinery off-gases

Chemical Reactions

The fundamental chemistry involves two primary reactions:

1. Steam Methane Reforming (Primary Reaction):
   
   CH₄ + H₂O → CO + 3 H₂ (ΔH=+206 kJ/mol)

2. Water-Gas Shift Reaction:
   
   CO + H₂O → CO₂ + H₂

Additional reactions include sulfur removal and methanation for final purification^[1][5].

Detailed Process Flow

The standard Topsoe hydrogen production process follows this sequence, as illustrated in Fig. 1:

Figure 1 - Topsoe SMR Process Flow Sheet for Hydrogen Production^[2]

1. Sulfur Removal (S-removal)
   • Natural gas or LPG/naphtha feedstock enters the desulfurization section
   • Organic sulfur compounds are hydrogenated and absorbed on zinc oxide beds
   • Sulfur content reduced to <0.1 ppm to protect downstream catalysts^[1]
      
2. Pre-reformer
   • Mixed feedstock and steam undergo initial reforming
   • Higher hydrocarbons are converted to methane, hydrogen, and carbon oxides
   • Enables higher heat flux in the main tubular reformer^[7]
      
3. Tubular Reformer
   • The centerpiece of the process where primary steam reforming occurs
   • Side-fired radiant wall design with catalyst-filled tubes
   • Operating temperature: 800-950°C
   • Steam-to-carbon ratio: typically 2.5-3.0
   • Achieves >90% methane conversion^[3][5]
      
4. Shift Conversion
   • Medium-temperature shift reactor converts CO to additional H₂
   • Copper-based catalysts used for low by-product formation
   • Further increases hydrogen yield^[1][7]
      
5. PSA Purification
   • Pressure Swing Adsorption separates high-purity hydrogen
   • Achieves 99.5-99.999+% hydrogen purity
   • Off-gases recycled as fuel to the tubular reformerr^[3][5]​​​​

• Heat Integration
  • Flue gas from tubular reformer provides heat recovery
  • BFW (Boiler Feed Water) generates process steam
  • Combustion air preheating improves thermal efficiency
  • Fuel gas consists of PSA off-gas supplemented with natural gas

Process Efficiency and Yields

Performance Metrics:

• Methane Conversion: >90% in tubular reformer
• Hydrogen Purity: Up to 99.999+%
• Energy Efficiency: 2.96-3.13 Gcal/1,000 Nm³ H₂ (315-333 MM Btu/scf H₂)^[1][5]
• Typical Product Composition: 75.5% H₂, 17.9% CO, 4.9% CO₂, 1.7% CH₄ (dry basis)

Advanced Operating Conditions:

• High outlet temperatures (up to 950°C) maximize conversion
• Low steam-to-carbon ratios (2.5) reduce equipment size and energy consumption
• Advanced steam reforming achieves 94% of theoretical efficiency^[7]

Process Economics

Investment and Operating Costs:

• Natural gas feedstock typically represents 65% of total operating costs at $4/MM BTU
• Tubular reformer design optimized for lowest capital investment
• High thermal efficiency reduces fuel consumption
• Modular design options available for smaller capacities

Modern Revamp Option: HTER Technology

For existing hydrogen plants requiring capacity increases, Topsøe offers the HTER (Haldor Topsøe Exchange Reformer) as a revamp solution (Fig. 2)^[1][4][8]:

Figure 1 - Schematic layout of an HTER revamp solution^[1]

• Capacity Increase: Up to 25-30% additional hydrogen production
• Integration: Installed in parallel or integrated with existing tubular reformer
• Economics: Investment cost ~60% of new plant for equivalent capacity
• Energy Efficiency: Utilizes hot process gas from tubular reformer effluent
• Proven Experience: Successfully implemented in multiple facilities worldwide

Commercial Experience

Topsøe's tubular reformer technology has extensive global deployment, supplying hydrogen production technology to refineries, petrochemical plants, and ammonia facilities worldwide:

• Global: Hundreds of tubular reformer installations ranging from 5,000 to 200,000+ Nm³/h
• Revamps: Multiple HTER installations including 110→137 MMscfd capacity increase in Asia^[1]

References

1. Jack Heseler Carstensen, Oct 2010, Additional hydrogen production by heat exchange steam reforming, Digital Refining.
2. Aldo Peiretti, 9^th Oct 2013, Haldor Topsøe Catalyzing your Business, Jornada sobre Gas de Síntesis y sus Derivados – Instituto Petroquimico Argentino (IPA).
3. Jack, 20^th Jun 2018, Hydrogen, steam methane reform (SMR) Process by Haldor Topsøe A/S, Oil & Gas Process Engineering.
4. Jack, 17th Jun 2019, Hydrogen HTER-p Process by Haldor, Oil & Gas Process Engineering.
5. Jack, 17^th Jun 2019, Hydrogen Steam Methane Reforming (SMR) Process by Haldor, Oil & Gas Process Engineering.
6. topsoe.com > processes > hydrogen (accessed 24^th Jun 2025)
7. Niels, R. Udengaard, Hydrogen Production by Steam Reforming of HC by Topsoe, Prepr. Pap.-Am. Chem. Soc., Div. Fuel Chem. 2004, 49(2), 906.
8. topsoe.com > our resources > knowledge > our products > equipment > heat exchange reformer hter (accessed 24^th Jun 2025)