Revolutionising reformer tubes

STEAM METHANE REFORMING

Revolutionising reformer tubes

As the global demand for hydrogen, syngas, and ammonia production grows, efficiency improvements in steam reformer furnaces have become a priority. To address these challenges, Paralloy has developed Omega technology, an advanced reformer tube design that enhances heat transfer, gas turbulence, and process efficiency. Dr Dominique Flahaut of Paralloy explores the real-world implications of Omega reformer tubes.

Steam reforming is the dominant industrial process for hydrogen and syngas production, where hydrocarbons (typically methane) react with steam over a catalyst to produce hydrogen (H2). This reaction occurs inside high-temperature reformer tubes, where efficient heat transfer is critical to maintaining optimal reaction kinetics.

However, traditional reformer tubes suffer from:

• Inefficient heat transfer: The heat transfer within the reformer tube is related to the tube surface area, which is smooth, limiting the overall heat transfer from the tube to the gas. As a result, the heat transferred to sustain the reaction is not optimal. The energy efficiency is not maximised.

• High fuel consumption: Due to the limited heat transfer efficiency, more fuel is required to maintain the necessary temperatures for the reforming process. This leads to substantial fuel consumption, keeping operation costly.

• Increased carbon footprint: The high energy requirements and reliance on fossil fuels contribute to a larger carbon footprint. Excessive CO2 emissions from the process contribute to environmental concerns, especially as industries strive for greener alternatives.

• Catalyst performance limitations: The effectiveness of catalysts in the reforming process is influenced by the gas temperature, which in turn relies on the efficiency of heat transfer. While recent advancements in catalyst development have focused on enhancing performance within the catalyst itself, a significant limitation remains in the heat transfer from the tube to the gas. Addressing this issue is crucial for unlocking the full potential of catalysts

To address these challenges, Paralloy has applied an innovative approach to tube design that enhances heat transfer, gas turbulence, and process efficiency (see Fig. 1).

Omega technology

Internal surface profiling for superior heat transfer

The Omega reformer tube features a profiled internal surface, increasing the internal surface area by more than 50%. This expanded surface area allows for:

• Greater heat absorption: By enhancing the catalyst’s ability to absorb heat with Omega, the thermal efficiency can be significantly improved. This means that the catalyst can operate more effectively at elevated temperatures, leading to faster reaction rates and higher yields in the reforming process. Improved heat absorption also contributes to better energy utilisation, making the overall system more efficient.

• More effective heat transfer: Optimising the heat transfer from the tube wall to the process gas is crucial for maximising the reforming performance. By employing Omega innovative design, we can enhance thermal conductivity and ensure that heat is efficiently transferred to the gas. This improvement not only reduces the amount of fuel needed to maintain optimal temperatures but also lowers operational costs and minimises environmental impact.

Gas turbulence for improved reaction kinetics

Traditional smooth-walled tubes create a more laminar gas flow, limiting contact between gas molecules and tube walls. Omega tubes introduce internal grooves, which generate gas turbulence, leading to:

• Better heat penetration toward the tube centre: By improving the heat penetration capabilities within the tube with Omega, temperature gradients can be significantly reduced. This ensures that heat is distributed more evenly throughout the entire cross-section of the tube, preventing hot spots and cold zones that can negatively impact the reforming process and tube reliability. As a result, the overall thermal stability of the system is enhanced, leading to more consistent performance, and longer tube life.

• More uniform catalyst bed temperature: Achieving a more uniform temperature across the catalyst bed is crucial for enhancing reaction efficiency. When the temperature is consistent, the catalyst can operate optimally, facilitating more effective chemical reactions. This uniformity helps to maximise the conversion rates of process gas and ensures that the catalyst is utilised to its full potential, ultimately improving the overall yield of hydrogen and syngas

• Faster gas heating: By optimising the heat transfer mechanisms, faster heating of the process gas can be achieved. This acceleration in heating not only shortens the time required to reach optimal reaction temperatures but also boosts reaction rates. As a result, the production of hydrogen is increased, making the process more efficient and economically viable. Faster gas heating contributes to a more dynamic and responsive system, allowing for better control over the reforming process.

Laboratory reforming test results

Laboratory tests using 300 mm-length reformer tubes consistently demonstrate a minimum of 10% improvement (double the initial expectations) in heat transfer coefficient with Omega tubes compare to usual reformer tubes, for all catalyst shapes and sizes. This higher heat transfer efficiency confirms the potential to increase process gas temperatures, to improve reformer performance and catalyst utilisation (see Fig. 2).

Performance benefits of Omega technology

Increased reformer tube efficiency

The improved heat transfer properties of Omega tubes lead to several key operational benefits:

• Lower tube wall temperatures: The improved heat transfer capabilities result in reduced temperatures at the tube walls. This not only extends the lifespan of the tubes by minimising thermal stress and wear but also leads to lower maintenance costs. With less frequent repairs and replacements needed, overall operational efficiency is improved.

• Higher process gas flow rates: With better heat transfer, the system can accommodate higher flow rates of process gas. This increase in flow rates directly contributes to greater production of syngas and hydrogen, enhancing the overall output of the reforming process. The ability to process larger volumes efficiently can significantly boost productivity and profitability.

• Increased compatibility with high performance catalysts: The optimised heat transfer environment allows for better integration with high-performance catalysts. This compatibility leads to more efficient reforming reactions, as the catalysts can operate at their optimal conditions. The result is improved reaction rates and higher yields of desired products, making the process more effective and economically advantageous.

Economic benefits: Fuel savings and cost reduction

The enhanced heat transfer efficiency of Omega tubes allows reformer furnaces to operate at lower firing rates while maintaining the same level of hydrogen or syngas output. This results in direct fuel savings, leading to substantial cost reductions.

Case study: Fuel savings in a large-scale reforming operation

In this case study, the impact of improved heat transfer properties in a large-scale reforming operation, focusing on fuel savings achieved through enhanced efficiency is examined.

Fuel consumption reduction: The operation experienced a conservative estimate of a 2% reduction in fuel consumption. This seemingly modest improvement can lead to significant savings over time, particularly in large-scale operations where fuel costs are a major expense.

Annual fuel savings: The reduction in fuel consumption translates to an impressive savings of 128,000 per year. This substantial figure highlights the effectiveness of the implemented changes in optimising the reforming process.

Cost reduction: With the annual savings of 128,000 million Btu, the operation realised a natural gas cost reduction of $537,600, based on an assumed price of

$4.2 per million Btu. This financial benefit underscores the economic advantages of improving heat transfer efficiency, demonstrating how operational enhancements can lead to significant cost savings.

In conclusion, this case study illustrates that even a small percentage reduction in fuel consumption can yield substantial savings in both energy usage and operational costs. The findings emphasise the importance Omega technologies that enhance heat transfer properties, ultimately leading to more efficient and cost-effective reforming operations.

Environmental impact: CO₂ emissions reduction

With lower fuel consumption, Omega tubes contribute to a significant reduction in CO2 emissions, aligning with global decarbonisation efforts.

Case study: Reduction of CO2 emission

In this case study, the significant environmental and economic benefits achieved through enhanced operational efficiencies in a reforming operation, focusing on the reduction of CO2 emissions is explored.

Annual CO2 emissions reduction: The operation successfully reduced its annual CO2 emissions by 7,060 tonnes. This substantial decrease not only contributes to a lower carbon footprint but also aligns with global efforts to combat climate change and meet regulatory requirements.

Cost savings from CO2 reduction: The reduction in CO2 emissions translates to total cost savings of €706,000 per year, based on an assumed CO2 price of €100 per ton. This financial benefit highlights the economic advantages of implementing strategies that lower emissions, demonstrating that environmental responsibility can also lead to significant cost reductions.

In conclusion, this case study illustrates the dual benefits of reducing CO2 emissions in a large-scale reforming operation. The substantial decrease in emissions not only supports sustainability goals but also results in significant financial savings.

These environmental benefits make Omega tubes an ideal solution for companies pursuing sustainability and ESG (Environmental, Social, and Governance) goals.

Conclusion

The Omega technology by Paralloy represents a significant leap forward in reformer tube design, offering:

• at least 10% improved heat transfer coefficient;

• lower fuel consumption (-2%);

• reduced CO2 emissions (-2%);

• longer reformer tube lifespan and improved catalyst efficiency;

• potential for new reactor designs, optimising industrial efficiency.

By addressing the key challenges in steam reforming, Omega technology by Paralloy provides a technical and economic advantage for industries looking to enhance performance while reducing environmental impact.

For hydrogen producers, ammonia plants, and syngas manufacturers, Omega reformer tubes set a new industry standard, ensuring a sustainable, cost-effective, and future-ready approach to high-temperature reforming.