PRODUCTION OF HYDROGEN 1. Steam Methane Reforming (SMR): This is the most common method for hydrogen production. It involves reacting natural gas (methane) with steam in the presence of a catalyst to produce hydrogen and carbon monoxide. The reaction is as follows: CH₄ + H₂O → CO + 3H₂
2. Partial Oxidation (POX): Similar to SMR, partial oxidation involves reacting natural gas with oxygen instead of steam. This process produces a mixture of hydrogen and carbon monoxide, which is known as syngas. CH₄ + ½O₂ → CO + 2H₂
3. Autothermal Reforming (ATR): A combination of steam methane reforming and partial oxidation, where natural gas is reacted with both oxygen and steam. This process offers better control over the hydrogen-to-carbon monoxide ratio in the syngas.
4. Electrolysis: This involves splitting water (H₂O) into hydrogen (H₂) and oxygen (O₂) using electrical energy. There are two main types of electrolysis: alkaline electrolysis and proton exchange membrane (PEM) electrolysis. This method requires a source of electricity, which can come from renewable sources to make the process more environmentally friendly.
5. Thermochemical Water Splitting: In this approach, high-temperature heat is used to drive the splitting of water molecules into hydrogen and oxygen. This process is still in development and involves various thermochemical cycles.
6. Biomass Gasification: Biomass materials, such as agricultural residues or wood, can be converted into a syngas through gasification. The syngas can then be separated to produce hydrogen.
PRODUCTION OF AMMONIA
1. Haber-Bosch Process: This is the most common method for ammonia production. It involves the reaction of nitrogen gas (N₂) from the air with hydrogen gas (H₂) derived from natural gas, using iron-based catalysts and high pressure and temperature. N₂ + 3H₂ → 2NH₃
2. Electrochemical Nitrogen Reduction: This is a newer and more environmentally friendly approach to ammonia production. It involves using renewable electricity to directly convert nitrogen from the air into ammonia, bypassing the high energy requirements of the Haber-Bosch process.
3. Hydrogenation of Nitrogen: Hydrogenation of nitrogen gas can be carried out over certain catalysts to directly produce ammonia. This method requires a hydrogen source, which can come from various hydrogen production methods.
4. Biomass Gasification and Ammonia Synthesis: Similar to biomass gasification for hydrogen production, biomass can also be converted to syngas and then used in ammonia synthesis.
These pathways represent a variety of methods for producing hydrogen and ammonia, each with its own advantages and challenges. The choice of pathway depends on factors such as availability of feedstock, energy sources, economic considerations, and environmental concerns.