Essar Steel, with a view to utilize the heat content of surplus steam and gases generated as a part of the steel manufacturing process has successfully installed a waste heat recovery-based (WHR) power plant at its Hazira facility.
The 19MW WHR plant was commissioned by the Essar Projects (EPIL) and Essar Steel Hazira-Power Infrastructure teams on May 9, 2012, with steam generated by blast furnace (BF) boilers.
The Steel Hazira facility uses three iron-making technologies– hot briquetted iron (HBI) / direct reduced iron (DRI), corex, and blast furnace (BF). The waste heat-based plant can generate power with the steam sourced from the newly installed HBI heat recovery boiler and the BF boilers. This effectively translates into no-cost fuel. Utilization of this steam will also substantially reduce the overall thermal emission from the Steel Hazira facility.
The HBI plant consists of four modules, each generating flue gas of about 2,00,000 Nm3/hr. The temperature of flue gas from HBI modules 1-3 is about 400 deg C, and that from HBI module 4, is about 350 deg C. The hot flue gas is, typically, discharged into the atmosphere through individual stacks atop the HBI module.
While the WHR power plant was designed for use in HBI module 1-4, it was modified to use steam from the standby boiler of the BF to use excess steam available by firing BF gas. This was necessary as Mod 1-4 are currently not in use, and on the other hand excess BF gas was getting wasted. For utilizing the excess gas from the BF, the project team laid a 1-km long pipeline to carry steam from the BF boilers to the turbine of the 19MW power plant. The modification was done using in-house design, engineering and execution.
The new WHR power plant is capable of generating 18.4MW with steam from the HBI boiler, or 12.7MW from the BF boiler.