The industrial furnace considered in this work is designed to remove organic flue gas components by thermal post-combustion. In the existing device air contaminated with organic components is mixed with auxiliary fuel (methane) in a conical diffuser. Optimization of the post-combustion with respect to heat recovery and, thereby, inlet temperatures led to non-proper stabilization of the flame followed by a thermal damage of the conical burner in the existing design. In order to protect the burner from thermal damage, a new robust swirl-induced lifted flame design has been considered. This design includes possibilities of varying the angle of the cone and the swirl number of the incoming mixture. It allows adjusting the lifted flame position as well as improving the oxidation of the organic component while simultaneously lowering the risk of thermal damage of the burner. The methodology for burner design is based on the numerical simulation of the turbulent reacting flow in the furnace. Results for velocity and temperature fields in the furnace for the old and the new design of the burner are compared. The final, optimized burner design enables the combustion of a wide range of gas mixtures with different calorific values at different thermal loads.