Abstract: A gas flare for burning waste gas comprises a stack with an upper chimney space, a lower combustion chamber, and a burner having one or more flame outlets positioned in the combustion chamber. A primary combustion air intake of the burner is in fluid communication with an ambient air intake to source primary combustion air therefrom. An airflow control device resides in a position operable to regulate secondary air flow from the ambient air intake to the flame outlet of the burner without obstructing the primary combustion air intake of said burner. The stack features a double hull design to preheat the ambient air as it travels to the burner, and a liquid containment/vaporization chamber is installed below the burner in heat exchange relationship with the preheated airflow path to the burner, whereby the chamber is warmed by the pre-heated combustion air and radiant heat from the combustion chamber.