Secondary Finishing: R&D Trends
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Courtesy of the Gas Research Institute |
Equipment
Combustion Technology
Energy Consumption
Process Description
R&D Trends
Improvements in reheating practice are centered on temperature uniformity, scale free heating, rapid heating rates, and temperature equalization and localized heating.
Temperature Uniformity – Skid Mark Eraser
Technology:
Skid Mark Eraser, Salem Corp.
Description:
High convection burner placed in furnace bed at intervals along skid
Phase II – Bench-scale laboratory program ending
Phase II – Installation at test site
Comments:
Market potential pusher furnace
Walking beam furnaces have lower temperature differences at skid marks
Gauge control corrects for skid marks on modern rolling mills
Scale Free Heating
Technology:
Scale Free Heating
Description:
Various reheat furnace concepts under development
Comments:
Limited market due to trend towards hot charging and direct rolling. Concern about retrofit capability.
Rapid Heating (BG and Air Products lines)
Technology:
Rapid Heat Technologies – British Gas Research Institute
Description:
High convection heating of steel
Comments:
Applied mainly to forging furnaces in North America
Technology:
Rapidfire Technology – Air Products and GRI
Description:
Direct oxyfuel flame impingement heating of workpiece.
Comments:
Potential for application in the following areas:
Thin/intermediate slab heating
Preheating of slabs for warm charging
Heating of transfer bars
Interstand heating in hot mills
Heating of Strip
Temperature Equalization and Localized Heating
Technology:
Radiative Converter – Tokyo Institute of Technology
Description:
Bench-scale laboratory program
Slab furnace is slightly larger than slab dimensions with stainless mesh on sides
Hot gas jet impinges on center of slab furnace; stainless mesh on sides of slab furnace is heated by the hot gases
Edge of slab heated by radiation from stainless mesh
Comments:
Improvement on heat shields for direct charging of slabs
Slab edge heating application.
Low NOx Burner Development
GRI has supported the development of the STAR burner concept (Staged Air Recirculating Burner). Hauck Manufacturing, Arthur D. Little, and Massachusetts Institute of Technology have developed this burner system with air staging and flue gas recirculation that can remove 90% of the NOx of conventional burners. The system is being scaled up to 15-20 MMBtu and is being adapted to cold-air firing or integral recuperation.
Steel Mill Process Heating Technology Study, Hatch Associates, GRI-95/0106, Gas Research Institute