Ammonia: a cracking opportunity for hydrogen
The rapid expansion of ammonia as a storage medium and a method for transporting hydrogen positions it as a potential key player in the energy transition
Joachim Harteg Jacobsen Topsoe
A mmonia’s increasingly rapid growth as an energy carrier and storage medium for hydrogen is a fairly recent phenomenon. As the world shifts towards low-carbon energy, ammonia has stepped forward as a potentially central player in the energy transition both as a fuel and transportation method for hydrogen. However, knowledge and experience are key to cracking open the available opportunities. The robust and scalable nature of the ammonia supply chain has solidified its appeal. With more than 20 million tons of ammonia already traversing the globe, along with the emergence of mega-scale blue hydrogen and ammonia projects and advancements in green production, the market is witnessing unprecedented interest. Hydrogen can be easily turned into ammonia using the established Haber-Bosch process. As ammonia can be transported as a liquid and has a much higher energy density than compressed hydrogen gas, it is an extremely efficient way to transport hydrogen globally. Once the ammonia reaches its destination, it can be converted back into hydrogen through the ammonia cracking process. Basics of ammonia cracking Ammonia cracking is a chemical process that converts ammonia (NH₃) into its constituent elements: nitrogen (N₂) and hydrogen (H₂). This reaction is typically carried out at high temperatures and can be catalysed by various catalysts. The process is endothermic, meaning it requires the input of heat energy. The catalyst helps to lower the activation energy required for the reaction to occur, thus increasing the reaction rate.
The most basic layout for an ammonia cracking process includes at least the following steps: ○ Vaporisation and preheating of the raw ammonia feed. ○ Catalytic decomposition of ammonia. ○ Removal of unconverted ammonia and purification of the hydrogen product. Large-scale ammonia cracking Many people mistakenly believe that ammonia cracking is a new or emerging technology. In a short time, it has attracted interest from established energy and fuel companies seeking a new business stream and from new players driven by innovation and ambition. Ammonia cracking is an important industrial process with several applications. One of its main uses is in the transportation of hydrogen gas, which is a valuable fuel and feedstock for various industries. Hydrogen can be turned into ammonia, a derivative product, via the Haber-Bosch synthesis, as explained below. The ammonia is then transported and converted back into hydrogen via the process of ammonia cracking. The resulting hydrogen can be used for the production of power, fuels or steel, natural gas replacement, and various industrial and chemical processes. The technology used in large-scale ammonia cracking is proven and has been in industrial use for decades. Topsoe’s first ammonia cracking technology was developed in 1978, with a focus on heavy water production. The largest ammonia cracking facility, capable of cracking 2 x 2,400 MT per day of ammonia in two parallel lines, was built in Argentina in 1993. Ammonia cracking can be centralised on a
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