Vacuum Furnaces Manufacturers

Vacuum furnaces are heat-treating furnaces that use a low atmospheric pressure instead of a protective gas atmosphere. It is used to minimize cracking; furnace outlet temperature is usually limited to around 750° F depending on the crude. Also to minimize and/or prevent coking, the furnace is designed with an average heat flux not exceeding 12000 Btu/hr/ft. High heat flux results in excessive temperatures contributing to high pressure fluid film and tube metal temperatures. Typical pipe diameters for vacuum furnaces are 4″ and 6″. To prevent coking and meet the sonic velocity limitations, the last pass of the radiant section is normally specified one standard pipe diameter larger. The amount of steam injected into the furnace tubes depends on its pressure and the thermodynamic effects on the system. A typical steam rate is about ½ of 1% of the volumetric flow rate.