Abstract Polymer agents are being used to increase the yield of oil-sand reservoirs. While these polymers are effective in increasing yield, they present problems in heater treaters used for oil/water separation. In particular, the heavy oil and polymer emulsion can coat the outer surface of heater treater firetubes, creating an insulating layer that causes high wall temperatures of the firetube. This can lead to early failure of the firetube, causing costly shutdowns and repair. The unique design of the distributed-flux burner solves this problem by providing uniform heat distribution over a greater area of the firetube compared to conventional burner technology. The burner utilizes premixed surface-stabilized combustion on a porous ceramic cylindrical surface. Heat release of the burner is kept constant along the entire burner surface. The burner is located in the center of the firetube along the tube axis, providing uniform heat distribution to the wall. This design significantly reduces the peak heat flux and film temperatures around the firetube found with conventional burners, which in turn reduces harmful thermal degradation of the firetube and coking of the oil mixture. Thermal analysis shows that for the same total energy input, the distributed-flux burner provides a 33% reduction in peak heat flux to the firetube wall compared to a conventional burner. The distributed-flux burner technology has been successfully used in heater treaters in California and in asphalt heating tanks in Canada. This paper will present design data from a recent installation of the distributed-flux burner in a heater treater for a Canadian oilfield using polymer injection that had previously suffered frequent firetube failures.