Ammonia is often overlooked when it comes to climate protection, although it does contribute significantly to global warming. Its production is responsible for around three percent of global CO2 emissions. It is mainly used as a raw material for fertilizers and is therefore essential for feeding the world’s population.
Ammonia is a colorless gas at room temperature. The chemical compound consists of nitrogen and hydrogen with the empirical formula NH3.
The most common method of ammonia production
Over 90% of the ammonia produced worldwide is produced in the direct synthesis using the Haber-Bosch process. During this reaction, nitrogen, which is obtained from air liquefaction, and hydrogen from steam reforming of natural gas or coal react with one another. This production method of ammonia from natural gas produces around 1.5 tons of CO2 per ton of ammonia.
By switching to renewable electricity to make ammonia, over 360 million tonnes of CO2 could be saved worldwide each year. Because green ammonia can be used both as a basic chemical, as a fuel, and as a comparatively easy-to-transport hydrogen storage medium, ammonia plays an important role in the global energy transformation.
The production of green ammonia is based on two steps. Initially, electricity from renewable energy sources is used to electrolyze water. The resulting hydrogen is then catalytically converted with atmospheric nitrogen to form ammonia.
Green ammonia has advantages over hydrogen
Ammonia can be easily transported by ship or pipeline and, due to its low flammability, the risk of explosion is lower than with hydrogen. Since ammonia has a vapor pressure of only 8.6 bar at 20 ° C and can be liquefied at -33 ° C, the requirements for storage tanks are significantly lower than for hydrogen. At the same time, the energy density of ammonia at ambient temperature is significantly higher than that of hydrogen gas under the same conditions. These properties also make it interesting as a marine fuel. For details on this topic: Ammonia as a fuel for ships – Greater Ideas