What is the Difference Between Steam Reforming and Autothermal Reforming?

Steam reforming and autothermal reforming are two different processes used in the chemical synthesis of pure hydrogen gas from methane. The key differences between these two methods are:

1. Heat Source: In steam reforming, the catalyst is contained in tubes that are heated by an external burner, while in autothermal reforming, a portion of the natural gas is burned to raise the temperature of the process gas before it contacts the catalyst.
2. Reaction Type: Steam reforming is an endothermic reaction, while autothermal reforming is an exothermic reaction.
3. Energy Efficiency: Autothermal reforming generally has increased energy efficiency and faster start-up times compared to steam reforming.
4. Hydrogen Production: In steam reforming, hydrogen is produced from the reaction of methane with steam, while in autothermal reforming, hydrogen is produced from the reaction of methane with oxygen and carbon dioxide.

The choice between steam reforming and autothermal reforming depends on factors such as the desired hydrogen purity, the required reaction rate, and the specific application. Steam reforming is typically considered the lower initial-cost option for hydrogen generation due to its simpler reactor design, while autothermal reforming is considered the higher-efficiency option due to more complete methane conversion.

Comparative Table: Steam Reforming vs Autothermal Reforming

Here is a table comparing the differences between steam reforming (SR) and autothermal reforming (ATR):

In summary, steam reforming uses steam to produce hydrogen and carbon monoxide from methane in an endothermic reaction. On the other hand, autothermal reforming combines steam reforming and partial oxidation processes, creating a thermally neutral process and an exothermic reaction. Autothermal reformers derives 55% of hydrogen from methane and 45% from steam.