Ammonia has emerged as a promising hydrogen carrier due to its high energy density, ease of liquefaction, and well-established transportation infrastructure. Its ability to store and release hydrogen through cracking makes it attractive for industries with high hydrogen demand, such as steelmaking and refining. However, integrating ammonia-derived hydrogen into these sectors presents technical, economic, and logistical challenges. This article examines the role of ammonia in supplying hydrogen for steel and refining industries, highlighting real-world applications and key hurdles.

In steel manufacturing, hydrogen serves as a reducing agent in direct reduced iron (DRI) processes, offering a pathway to decarbonize an industry responsible for approximately 7% of global CO2 emissions. Ammonia cracking units can provide high-purity hydrogen for this application, but the process requires careful temperature management due to the endothermic nature of ammonia decomposition. The cracking reaction occurs at 800–900°C, demanding significant energy input and advanced catalyst systems to maintain efficiency. Pilot projects, such as those by Thyssenkrupp in Germany, have demonstrated the feasibility of using ammonia-derived hydrogen in blast furnace operations, though scaling remains constrained by the availability of low-carbon ammonia and the need for retrofitting existing plants.

Refineries consume large quantities of hydrogen for hydroprocessing, including hydrodesulfurization and hydrocracking. Ammonia-based hydrogen supply can reduce reliance on steam methane reforming (SMR), which accounts for over 90% of refinery hydrogen but carries a high carbon footprint. A case study from Japan’s JERA demonstrates the integration of ammonia cracking at the Yokohama refinery, where hydrogen is extracted and fed into the hydrodesulfurization unit. The project revealed two critical challenges: the need for stringent purification to remove residual ammonia (below 0.1 ppm to prevent catalyst poisoning) and the higher operational costs compared to conventional SMR when carbon pricing is absent.

The energy penalty of ammonia cracking is a universal concern. Decomposing ammonia into hydrogen and nitrogen consumes approximately 30% of the energy content of the produced hydrogen, reducing overall system efficiency. This penalty is exacerbated when renewable energy is used for cracking, as seen in Australia’s Renewable Hydrogen and Ammonia Supply Chain initiative. The project reported a 22% drop in net energy output compared to direct hydrogen use, underscoring the trade-off between transportability and efficiency.

Storage and handling complexities also hinder adoption. Ammonia’s toxicity necessitates specialized storage tanks, leak detection systems, and safety protocols, increasing capital expenditures. In steel plants, where space is often constrained, the footprint of cracking units and auxiliary systems can complicate integration. A study by ArcelorMittal in Belgium estimated that retrofitting an ammonia-to-hydrogen system requires 15–20% more space than equivalent SMR infrastructure.

Economic viability remains tightly coupled to regional policies and ammonia supply chains. In regions with established ammonia production, such as the Middle East, the cost of ammonia-derived hydrogen can compete with SMR when carbon capture costs exceed $50 per ton. However, in areas dependent on imported ammonia, transportation costs dominate. South Korea’s POSCO reported a 40% increase in hydrogen costs when using imported ammonia compared to on-site SMR, based on 2022 pilot data.

Material compatibility issues further complicate deployment. Ammonia’s corrosiveness demands high-grade stainless steel or nickel alloys for cracking reactors and piping, increasing upfront costs. Refineries face additional hurdles due to the sensitivity of hydroprocessing catalysts to trace contaminants. A 2021 trial at a European refinery found that even with purification, ammonia-derived hydrogen accelerated catalyst deactivation by 12% compared to pipeline hydrogen.

Despite these challenges, advancements in cracking technology are improving prospects. Novel catalysts, such as ruthenium-based formulations, have demonstrated 10–15% higher conversion efficiency at lower temperatures in lab-scale tests. Membrane reactors, which separate hydrogen during decomposition, show potential to reduce purification costs. The HELMETH project in Germany achieved 85% hydrogen recovery using such systems, though durability remains a concern beyond 5,000 hours of operation.

Logistics optimization is another area of progress. Co-locating ammonia cracking facilities with industrial clusters can mitigate transport costs. The Netherlands’ Port of Rotterdam initiative plans to centralize ammonia cracking for multiple users, leveraging economies of scale. Early analysis suggests this approach could cut hydrogen delivery costs by 18% compared to standalone units.

The regulatory landscape is evolving to support ammonia-based hydrogen. Japan’s Green Growth Strategy includes subsidies for ammonia cracking in steel and refining, while the EU’s Delegated Act on Renewable Fuels of Non-Biological Origin recognizes ammonia as a valid hydrogen carrier. These measures are critical to bridging the cost gap with conventional methods.

In summary, ammonia-derived hydrogen presents a viable but complex solution for decarbonizing steel and refining industries. Successful integration hinges on overcoming energy penalties, material limitations, and cost barriers through technological innovation and coordinated policy support. As pilot projects transition to commercial scale, the lessons learned will shape the role of ammonia in the industrial hydrogen economy. Future efforts must prioritize efficiency gains, supply chain resilience, and cross-industry collaboration to unlock its full potential.