The Advantages and Disadvantages of Iron Catalyst in Haber Process

The manufacture of ammonia is crucial to use in fertilizer as it helps to maintain food production for billions of people worldwide. Nitrogen compound in fertilizer can consider as the most effective compost because plants need it to produce proteins. Besides, phosphorus and potassium elements frequently found in fertilizer. Fertilizer also essential to keep soils productive, thus help to sustain healthy crops.

Generally, ammonia can be produced via the Haber-Bosch process. The Haber-Bosch process is an industrial process for manufacturing ammonia from nitrogen and hydrogen reaction, using an iron catalyst at high temperature and pressure.

 BENEFITS OF IRON CATALYST 

Figure 1: Iron Catalyst

 

The significant advantage of using iron catalyst (figure 1) in the process is it readily available and plentiful, thus making the use of it on the metric ton scale feasible. The production can produce tons of ammonia per day by using a catalytic reaction. For example, 1800 tons ammonia per day requires a gas pressure of at least 130 bar, temperatures of 400 to 500 °C and a reactor volume of at least 100 m³. Iron also is an inexpensive catalyst used in the making ammonia via Haber process. Many other metals are not nearly as inexpensive. Next, iron catalyst helps to attain an acceptable yield in good time. Therefore, it produce high yield of product which is ammonia. Because of reasonably low cost, readily availability, easy handling, life cycle and activity, iron was the ultimate catalyst in the ammonia manufacturing.

DISADVANTAGES OF IRON CATALYST AND HABER PROCESS

However, pure iron catalysts are very limited. It must include cobalt in the reaction. The disadvantage of using an iron catalyst in the Haber-Borsch process is they can form rust from iron oxide. Meanwhile, in the Haber process, ammonia is not compatible with the copper element. It cannot use in systems that used copper pipes since most of the industry used copper pipes in reactors. Next, the Haber process consists of high energy consumptions level. According to a paper published in CellPress, the production of ammonia via the Haber-Bosch process, is the most energy-intensive commodity chemical, responsible for 1%–2% of global energy consumption and 1.44% of CO2 emissions. The Haber-Bosch process also consumes natural gas such as fossil fuel almost 3 to 5 per cent of (Yuyu et al., 2019). Furthermore, ammonia is toxic, flammable, and poisonous at the individual level, high concentrations. Ammonia is harmful towards human health as they resulted in corrosive to the skin, eyes, and lungs. The exposure of ammonia can irritate the throat and cause coughing (Diana et al., 2018). Therefore, ammonia must be appropriately handled and implement safety precaution. Using ammonia as fertilizer also bring disadvantages towards human health such as causes eutrophication (Figure 2) which algae growth and cover the surface of the water body, then giving further impact across the ecosystem. Besides, ammonia will initiate blue baby syndrome, which affects by nitrate in drinking water, thus disturbs the blood circulation by reducing the hemoglobin level in human body. Lastly, ammonia is at its disadvantage by turning the soil acidic which can trigger the crop growth.

Figure 2: Eutrophication Process

References:

1. Ashida, Y., Arashiba, K., Nakajima, K., & Nishibayashi, Y. (2019). Molybdenum-catalysed ammonia production with samarium diiodide and alcohols or water. Nature, 568(7753), 536-540  https://doi.org/10.1038/s41586-019-1134-2.

2. Jyllian Kemsley. (2011).  Iron Complex Turns Nitrogen and Hydrogen into Ammonia. Chemical and Engineering News, 89, 46. http://dx.doi.org/10.1126/science.1211906

3. Diana, M. P., Roekmijati, W. S., & Suyud, W. U. (2018). Why it is often underestimated: Historical Study of Ammonia Gas Exposure Impacts towards Human Health. In E3S Web of Conferences (Vol. 73, p. 06003). EDP Sciences. https://doi.org/10.1051/e3sconf/20187306003