Regenerative Heating Cell
Development of the Regenerative Cell for Reheating Steel Ingots
The regeneration of heat from exhaust gases leaving industrial units is one of the efficient technologies applied for waste heat recovery with intention to reduce fuel consumption and carbon dioxide emission.
The project Regenerative Cell for Reheating Steel Ignots involves reconstruction the heating system of a typical recuperative cell #7-2 of 10 MW for steel ingot reheating at the Rolling Department of an industrial Partner. The recuperative system, formed by the obsolete and inefficient tube ceramic heat exchangers, was replaced with small-sized regenerators with a nozzle made of corundum spheres of 10-20 mm.
The project lasted for 2 years with a number of sub stages including energy audit of the recuperative cell #7-2, development of the business-plan, basic-engineering and simulation, design engineering, reconstruction and commissioning.
Regenerative Heating System and Simulation of Its Performance
Instead of two burners, traditional solution for a regenerative heating system, connected to corresponding regenerators, in this Project, only one burner is used, located in the center of the cell. This burner device is designed in such a way that a reversible scheme of fuel combustion and gas flow provides recirculation of furnace gases, thereby increasing the uniformity of ingot heating and reducing metal waste.
Developed technical solutions allow also to eliminate gas / air leakage, a feature of the previous heating system.
Due to a fairly frequent change in the direction of gas flows (every 2-3 minutes) in the reconstructed cell, a high uniformity of the temperature field is achieved along the profile of the working space.
The results of measurements of current loads during rolling, measurements of the temperature of the head and bottom of the ingots when they were discharged from the cell showed high quality heating of the ingots. During operation, there was no return of ingots for heating.
According to the results of the balance tests of the heating cell 7-2, the specific consumption of fuel during heating of the ingots was 97.6 kWh per ton, the decrease by 33% compared to the previous system.