Question

As a group, create a single schematic drawing of a factory that uses the Haber-Bosch process and the Ostwald process to make \(\mathrm{NH}_{4} \mathrm{NO}_{3}\) fertilizer. The factory may only take in \(\mathrm{N}_{2}(g), \mathrm{H}_{2}(g)\) and \(\mathrm{O}_{2}(g) .\) Pass your diagram around the group and have each group member add one step in the process. Where might the factory obtain \(\mathrm{H}_{2} ?\)

Short answer

To create the schematic drawing of the factory: 1) Show 2 and 2 reacting to make ammonia (H3) via the Haber-Bosch process. 2) Convert ammonia to nitric acid (O3) using the Ostwald process. 3) Neutralize nitric acid with additional ammonia to form ammonium nitrate (H4NO3). Mention that hydrogen (2) can be sourced from natural gas or water electrolysis.

Step-by-step solution

Understand the Haber-Bosch Process

The Haber-Bosch process synthesizes ammonia (H3) from nitrogen (2) and hydrogen (2). Represent this in the schematic by including a reactor where 2 and 2 react under high pressure and temperature in the presence of a catalyst.

Incorporate the Ostwald Process

The Ostwald process converts ammonia (H3) into nitric acid (O3). Include in the diagram a second stage where the ammonia reacts with oxygen (2) over a platinum catalyst to form nitric acid and water.

Formation of Ammonium Nitrate (H4NO3)

Ammonium nitrate is made by neutralizing nitric acid with ammonia. Add a mixing stage in the schematic where O3 and additional H3 combine to produce H4NO3.

Diagram Integration

Compile all steps into a single schematic diagram, ensuring there is a clear flow of materials from the intake of 2, 2, and 2, through the Haber-Bosch and Ostwald processes, to the production of H4NO3 fertilizer.

Source of Hydrogen (2)

Hydrogen can be obtained from natural gas (methane) or through the electrolysis of water. Include a note in the schematic indicating the potential sources of hydrogen.

Key concepts

Ammonia Synthesis

The synthesis of ammonia (H_{3}) is a cornerstone in industrial chemistry, crucial for creating fertilizers and various other compounds. At the heart of this process is the Haber-Bosch method, which efficiently converts atmospheric nitrogen (N_{2}) and hydrogen (H_{2}) into ammonia.

This process takes place in a reactor at temperatures around 400-500°C and pressures up to 200 atmospheres. A catalyst, often iron with promoters like potassium and aluminum oxide, is used to accelerates the chemical reaction. The balanced chemical equation for the ammonia synthesis is:
<3N_{2} + 3H_{2} <-> 2NH_{3}>.

The success of the Haber-Bosch process made it possible to produce ammonia on a large scale, leading to the Green Revolution and significantly impacting global agriculture. Ensuring the right conditions — temperature, pressure, and catalyst— is key to maximizing the yield of ammonia while minimizing energy consumption.

Nitric Acid Production

Following ammonia synthesis, the next step is the production of nitric acid (HNO_{3}), critical in the manufacturing of ammonium nitrate fertilizer. This transformation is carried out through the Ostwald process, which oxidizes ammonia using a series of careful steps.

The first stage involves mixing the ammonia (NH_{3}) gas with oxygen (O_{2}), which reacts over a platinum catalyst to yield nitric oxide (NO) and water (H_{2}O). The overall reaction can be summarized as:<4NH_{3} + 5O_{2} -> 4NO + 6H_{2}O>.

In subsequent steps, nitric oxide is further oxidized to nitrogen dioxide (NO_{2}), which is then absorbed in water to produce nitric acid. This acid-base reaction is precisely controlled to avoid the production of unwanted by-products and to ensure high purity of the nitric acid required for fertilizer production.

Ammonium Nitrate Fertilizer

Ammonium nitrate (NH_{4}NO_{3}) is a widely used nitrogen-rich fertilizer that is produced by neutralizing nitric acid with ammonia. It is favored by farmers for its high nutrient content and water solubility, which make it easily absorbable by plants.

The production process involves a careful reaction, as an exothermic neutralization occurs: NH_{4}NO_{3}>.

It’s crucial to monitor the temperature during this process to prevent the decomposition of the products and to manage the concentration of the nitric acid and ammonia. The final product is a white crystalline solid that can be granulated for ease of application in agriculture. Due to its high nitrogen content, it provides rapid growth benefits to crops but must be handled with care given its potential for misuse.

Industrial Chemistry

Both the Haber-Bosch and Ostwald processes are prime examples of industrial chemistry — a branch of chemistry focused on converting raw materials into products that are beneficial for society. Industrial chemistry includes designing, optimizing, and maintaining chemical processes on a commercial scale.

Key elements of this field include ensuring reactant purity, catalysis, precise reaction control, and energy efficiency. These principles ensure that the processes are sustainable, cost-effective, and safe. The integrated system, which begins with the extraction of hydrogen, likely from natural gas or electrolysis, and ends with the production of ammonium nitrate fertilizer, embodies the complexities and the ingenuity of modern industrial chemistry.

The overarching goal is to fulfill the growing global demand for food by producing fertilizers that increase crop yields. However, it is also essential for the industry to address environmental and safety concerns to reduce the ecological footprint of these chemical processes.