Höyryreformoinnin

Höyryreformoinnin, also known as steam reforming, is a widely used industrial process for producing hydrogen and syngas from hydrocarbons. It is the most common method for producing hydrogen globally, particularly for ammonia production, petroleum refining, and methanol synthesis. The process involves reacting a hydrocarbon, such as natural gas (primarily methane), with steam at high temperatures, typically between 700 and 1000 degrees Celsius, and under pressure, usually between 3 and 25 bar.

The primary reaction involves methane and steam, producing hydrogen and carbon monoxide: CH4 + H2O <=> CO + 3H2. This reaction is endothermic, meaning it requires a continuous supply of heat. A secondary reaction, the water-gas shift reaction, often follows to maximize hydrogen production and convert carbon monoxide into carbon dioxide: CO + H2O <=> CO2 + H2. This reaction is exothermic.

Catalysts, commonly nickel-based, are crucial for facilitating these reactions at achievable temperatures and rates. The process typically occurs in multiple stages within reformer tubes packed with catalyst. The heat required for the endothermic steam reforming reaction is supplied by burning a fuel gas in an external furnace surrounding the reformer tubes.

The output of the steam reforming process is a mixture of hydrogen, carbon monoxide, carbon dioxide, and unreacted steam and hydrocarbons, known as syngas. This syngas can then be further processed to isolate pure hydrogen or used directly in other chemical syntheses. Variations of steam reforming exist, including autothermal reforming and partial oxidation, which utilize different combinations of oxidants and heat sources.