The optimum concentration for combustion is typically what?

The optimum concentration for combustion is often considered slightly rich of stoichiometric. This means there is a bit more fuel present than the precise amount needed for complete combustion of the available oxygen. Operating in a slightly rich environment can enhance combustion efficiency and ensure that the fuel fully ignites.

When combustion occurs at slightly richer conditions, there is a better likelihood of complete burning of the fuel, especially in scenarios where fuel mixing may not be ideal or where there are variations in fuel composition. A rich mixture can also produce higher flame temperatures, which can be beneficial for certain applications.

In contrast, being exactly stoichiometric might not account for factors like incomplete mixing or combustion inefficiencies, and being slightly lean could result in insufficient fuel for ignition, leading to incomplete combustion and potentially higher emissions. Therefore, the balance of slightly rich concentrations ensures a more reliable combustion process.