Case Study 2 - Steel plant – scrap melting Arc Furnace.

Waste Heat Recovery on Flue Gases exhausted by scrap melting Arc Furnace

System Description

Initial situation

• Scrap melting Arc Furnace exhausts huge amount of dust laden flue gas at very high temperature of 1200°C approx.
• Arc furnace operation is a batch type, constituting melting time and idle time

Challenges

• The heat was required to be recovered from very hot & dusty flue gas
• The heat recovery was to be done in batches and was to be converted into steady state of utput

Existing Process Schematic

Solution offered

• Heat is recovered in the form of medium pressure steam in waste heat recovery boiler. The steam is generated in batches. Suitable system is provided to absorb the cyclic operation and give out steam in steady state condition
• The dry and saturated steam is superheated as per requirements of vacuum degassing in fired super heater
• The super heated steam is supplied to Vacuum Degassing plant
• The system includes patented vertical co-flow design of waste heat recovery boiler and proprietary & developed special diverter damper suitable to handle flue gas at high temperature

Note : It is a proposed system. Installation is yet to take place

Results

Revised Process Schematic