Vacuum Degassing (VD) Furnace

Vacuum Degassing (VD) Furnace

        Vacuum Degassing (VD) Furnace is mainly used for reducing dissolved gases (H₂, N₂, O₂) in molten steel, homogenizing steel composition and temperature, removing oxide inclusions, and creating favorable conditions for final desulfurization treatment.

VD Process

        During VD treatment, molten steel is stirred by argon gas injected through a porous refractory plug installed at the bottom of the ladle. This promotes efficient bath homogenization and enhances degassing performance. The argon connection is established automatically after the ladle is positioned inside the vacuum vessel. 

        The vacuum vessel is evacuated to the required operating pressure through one of the following systems:

       •Steam jet ejector system

       •Combined steam ejector and water ring pump system

       •Dry mechanical pump system

        Process emissions are extracted through the vacuum pumping system and treated before discharge. Cooling water from the vacuum system is circulated through the hotwell and cooling tower system for continuous operation.       

        Dry mechanical vacuum pump systems are typically designed in 3-stage or 4-stage configurations, combining rotary lobe pumps and screw pumps. Multiple pump modules can be installed depending on the required suction capacity and refining demand.

Features of VD Dry Mechanical Pump System

        •Lower operating costs compared with steam ejector systems

        •No steam consumption required

        •No direct-contact cooling water required

        •Compact and modular design

        •Precise vacuum control through gas dilution

        •Energy-saving and environmentally friendly operation

        •Redundant system configuration available upon customer request

Advantages of VD Refining

       •Efficient hydrogen and nitrogen removal

       •Improved steel cleanliness

       •Better temperature and composition homogenization

       •Enhanced desulfurization performance

       •Reduced non-metallic inclusions

       •Improved mechanical properties of finished steel products

       •Stable refining quality and process reliability

VD Furnace Control diagram 

VD Furnace pump Control