Indirect Line Heaters are designed to heat a gas or oil stream contained in high pressure flow coils that are immersed in a liquid bath to receive heat indirectly from a firetube. The heater shell operates at atmospheric pressure and houses a fuel gas preheat coil and connections for a thermometer, temperature controller, drain, and fill cap. The flow coils and firetube are welded into the flanged shell ends and inserted independently into opposite ends of the vessel, thereby facilitating their removable and replacement without interfering with each other.

Indirect Line Heaters are normally installed upstream of surface production equipment to preheat the well stream and prevent the formation of natural gas – water hydrates associated with pressure reduction. Line heaters also assure good gas – liquid separation by elevating inlet temperatures. Flow coils are available in a variety of sizes and configurations to satisfy specific heat transfer and pressure drop requirements.