In order to initiate the reaction of burning methane (CH4) with oxygen (O2), an input of energy is required to overcome the activation energy barrier. Activation energy is the minimum amount of energy needed for a chemical reaction to start.
There are several ways to provide activation energy for the combustion of methane with oxygen:
Heat: One common method is to supply heat to the reaction mixture. Heating the reactants increases their kinetic energy, causing them to move more rapidly and collide with greater force. Sufficient heat energy can overcome the activation energy barrier and initiate the reaction. Once the reaction starts, it becomes self-sustaining as it releases heat.
Spark or Flame: Another way to provide activation energy is by introducing a spark or flame to the reaction mixture. The spark or flame carries sufficient energy to initiate the combustion reaction by providing the necessary activation energy. Once the reaction starts, it continues to burn as long as there is a sufficient supply of fuel (methane) and oxygen.
Catalyst: A catalyst is a substance that can lower the activation energy required for a chemical reaction without being consumed in the process. While not directly providing activation energy, a catalyst facilitates the reaction by creating an alternative pathway with a lower activation energy. For example, the use of a platinum catalyst in the catalytic combustion of methane can significantly reduce the activation energy required for the reaction.
It's important to note that once the combustion reaction begins, it becomes self-sustaining due to the exothermic nature of the reaction. The heat generated from the initial reaction provides the necessary energy to continue the combustion process until one or both of the reactants (methane or oxygen) are depleted.