Process for the conversion of a glass furnace with the aid of a combustion with oxygen

Provided is a process for the production of a loop-shaped flame in a glass furnace. The furnace includes, in a rear part, a glass melting zone heated by injecting through at least one port a fuel gas and an oxidizer gas having more than 50 vol % of oxygen and, in a front part, a glass refining zone. The process involves defining a stoichiometry coefficient Ks of the flame in the melting zone or the refining zone according to the following formula: The oxidizer gas and the fuel gas injected through at least the first port are adjusted to obtain a stoichiometry coefficient Ks in the glass melting zone equal to at most 0.8. A fuel-oxidizer mixture is injected into the refining zone to obtain a stoichiometry coefficient Ks in the refining zone which is greater than the stoichiometry coefficient Ks in the melting zone and which is between 0.8 and 1.5. An oxidizer gas is injected into the melting zone in the vicinity of a fume discharge zone to obtain a quantity of oxygen in the fumes of between 0.5 and 3% by volume. The invention has particular applicability to end-fired furnaces with recuperators in which the blocking of the recuperator makes it necessary to employ ports with oxygen during the blocking of the recuperator, to maintain output at an acceptable volume.