Direct Fired Heater Reboiling refers to the provision of heat to the bottom of industrial distillation columns, boiling the liquid from the bottom of a distillation column to generate vapors which are returned to the column to drive the distillation separation. The heat supplied to the column by the reboiler at the bottom of the column is removed by the condenser at the top of the column. Proper reboiling operation is vital to effective distillation. In a typical classical distillation column, all the vapor driving the separation comes from the reboiler. The direct fired heater reboiler receives a liquid stream from the column bottom and may partially or completely vaporize that stream. Steam usually provides the heat required for the vaporization. BIH supply reboiler furnaces used in such application.