PRISMA Impianti has developed an important project for Marcegaglia Ravenna, in order to increase the production and to revamp the air cooling system of the existing continuous galvanizing line No. 4.
Taking into account that this is a very recent production line, commissioned in 2010, most parts of the existing equipment were able to support the expected increase in production after changing the cooling section with our solution, with the following characteristics:
. Higher power, to increase productivity and to reduce sheet defects
. Lower energy consumption
. Same size of the previous solution
The general layout of the existing section was not modified, neither was the layout of the cooling tower. Instead, new equipment was installed: horizontal air coolers, vertical air coolers and a new top deflection roll.
The focus of the project was the development of a mathematical-physical model, based on an experimental formula, able to calculate the optimal heat exchange coefficient, performed by forced convection.
The lower air flow of the installed fans has made it possible to reduce dimensions and weight of the transport ducts, which lowered energy consumption.
After the start-up, the production line performed with a significant reduction of zinc coating defects (about 70 %). In addition to the increase in productivity as required by the purchase order, the savings in electric energy, theoretically calculated, could be confirmed at 20%.
This project is an example of our capabilities to design customized solutions based on customer requirements, from the basic engineering to the startup.