Saving Electrical Energy as well as Heat timings by preheating the Scrap Metal charge and DRI is an established practice with EAF ( Electric Arc Furnaces). This same method can be adopted for Induction Furnaces as well, utilizing the Vertical Shaft kiln for preheating the charge using either the waste heat in case of a CAp Topped Induction Furnace or using cheap fuels like Coal or Biomass.

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2.  Preheating of scrap charge utilizing waste heat is becoming a
regular practice with EAF (Electric Arc Furnace).
 Preheating is performed in charging baskets, shaft furnaces or
in specially designed scrap conveyers.
 In the early 1990s EAFs with a direct-coupled scrap preheating
function were developed.
 A single shaft furnace can save electricity up to 70 kWh/ton of
liquid steel.
 The finger shaft furnace allows energy savings up to 100
kWh/ton liquid steel in an EAF, or 25% of the overall electricity
input.
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3.  Preheating of scrap is not yet an adopted practice for the
Induction Furnace (IF) process.
 Preheating of scrap and DRI to 450-650 Degree C would
considerably decrease heat timing and save electricity.
 Cap topped IF’s can be modified for utilization of waste heat
for preheating of scrap and DRI.
 But as most Induction Furnaces are open-topped, it is
difficult to capture and utilize their waste heat.
 The process requires the usage of External Heating Source.
 Several methods can be adapted for preheating Scrap and
DRI for Induction Furnaces.
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4.  Reduces Heat Timings.
 Significantly reduces Electricity consumption.
 De-oxidizes, De-volatilizes, De-humidifies scrap metal.
 Reduces Slag generation.
 Improves Refractory Lining Life.
 Reduces Pollution.
 Improves Molten Metal Quality.
 Low Cost Add-on.
 High return on investment.
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5.  Furnace Capacity.
 Scrap Grade, Sizes.
 Scrap / DRI feeding ratio.
 Platform Layout.
 Platform Space.
 Utilizable space near the Furnace platforms.
 Overhead Crane Height.
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6.  Scrap Charging Baskets
 Conveyor Process
 Rotary Kiln
 Vertical Kiln
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7.  The oldest process of preheating scrap.
 Here scrap is loaded into a steel basket and placed inside a
special kiln for heating by an overhead crane.
 Once heated the material is again transferred by crane for
discharge into the Induction furnace.
 Cheapest system of preheating scrap with least capital cost.
 The disadvantages are: high emissions, high handling costs,
low preheating levels and the difficulty in unloading.
 This process not effective for preheating DRI.
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8.  Comprises of a metal mesh conveyor belt, which carries the
scrap via a tunnel, down to the furnace through a “hot heel.”
 Allows for continuous charging during the melting process.
 Most suitable for Capped IF ‘s to utilize waste heat.
 Otherwise requires a tunnel furnace to heat up the charge.
 Can handle both scrap metal and DRI.
 Needs additional equipment to be placed on the Furnace
platform that could hamper work process.
 Considerable capital cost involved.
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9.  A small rotary kiln can also be used to preheat the scrap.
 It can handle both scrap metal and DRI.
 Combustion of heating fuel needed for the process.
 Large area requirement so it has to be fitted outside the plant.
 Shall require a Basket or conveyer to transfer material to the
Induction Furnace.
 Scope for cooling of charge during transfer.
 Considerable capital investment.
 Uneconomical in-terms of Fuel costs.
 Slow Process of heating.
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10.  Is the most practical solution for preheating scrap metal.
 Requires little space at it has a very small footprint.
 It can be positioned near to the Induction Furnace.
 It can be loaded by magnet crane.
 Heated material can be directly discharged into the Induction
furnace.
 Negligible heat loss during transfer of charge.
 The heated air is recycled to improves heating efficiency.
 Can run on waste heat in case of Capped Induction Furnaces.
 Otherwise can utilize a wide variety of cheap fuels.
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11.  Furnace Oil - Advantages: Flexibility,
Disadvantages: Expensive.
 Coal (Lump) - Advantages: Cheap
Disadvantages: Pollution, Sulfur infusion, Bottom & Fly
Ash generation, incomplete combustion.
 Coal (PCC) - Advantages: Cheap, Complete Combustion.
Disadvantages: Pollution, Sulfur infusion, large area
requirement, Capital cost.
 Coal Gas - Advantages: Cheap, Low Pollution.
Disadvantages: High Capital Cost, large area requirement, Ash
& Tar generation, possible Sulfur Infusion.
 Biomass Briquettes (Fluidized Bed)
- Advantages: Cheap, Low Pollution, Low Ash, No
Sulfur.
Disadvantages: Limited Availability, Covered Storage.
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12.  The vertical kiln consists of a refractory lined metal cylinder.
 Its internal volume is more than the furnace capacity.
 The Kiln has a airtight cap on top, which is opened for loading.
 It has a firebox at the bottom.
 A special heat resistant/cooled grate separates the firebox and
the charge above.
 The kiln is equipped with a collapsible chute, which feed the
preheated material directly into the Induction furnace.
 The hot gases from the top of the kiln are re-circulated by the
blower and fed back as auxiliary air.
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13.  The Oil/Gas/PCC burners or the Coal or Biomass in the
firebox are ignited.
 The scrap metal & DRI is loaded via a magnet crane into the
Vertical Kiln through the opened top.
 The top cap is closed.
 The charge is heated to the needed temperature.
 The material is progressively discharged directly into the
Induction Furnace via a Collapsible Chute or with human
assistance.
 Fresh Material is loaded for preheating.
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14.  Techno-Commercial Feasibility Study.
 Preparation of Complete Project Report.
 Government Liaison.
 Machinery selection.
 Vendor selection.
 Complete Technical Assistance till commissioning.
 Help in preparing Press releases & Publicity material.
 Market Development.
 Undertake Turnkey Consultancy Project.
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15. We Specialize in:
•Fuel Handling & Planning
•Fuel Emulsification
•Diesel Saving
•Coal & Biomass Gas
•Other Energy Related Services
RA.D.E INITIATIVE, GOA, INDIA
Contact: RAVI DEKA
Mobile No: +91-9822910300
Email : rade.initiative@gmail.com
www.rade.co.in
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