Uso da água de chuva para repor perdas por evaporação em processos de laminação a quente de aço

Abstract

Awareness about the importance of the rational use of water resources and concern about water pollution in the world is increasingly needed. The reduction of operating costs has been a competitive differential between the industries in general and the sustainable water systems allow, in addition to cost reduction, greater operational safety of the industrial plant. Most of the water used in the steel process is due to the refrigeration of equipment and processed materials. This characteristic has required companies to implement measures that increase the volume of recycled water in their processes. However, part of this water evaporates or is lost through leaks, thus needing to be replaced. The objective of this work is to propose the use of rain water as make-up water to the steel industry, especially the hot-rolling process, where approximately 114 liters of water are evaporated per ton of steel finished. For practical contextualization, the simulation of rainwater harvesting, storage and use was carried out in a hot rolling mill located in the Vale do Aço region of Minas Gerais, with a nominal production capacity of 4,600,000 t / year, which can evaporate More than 500 thousand cubic meters of water per year. Using the simulation method described in ABNT NBR-15527 and using the sheds roofs, which occupy the area of approximately 180 thousand square meters, the potential for capturing more than 210 thousand cubic meters of water per year was reached, considering the monthly averages of rainfall from 2006 to 2016. At the end are presented curves that facilitate the choice of the best volume of reservoir as a function of the percentage of attendance to annual demand, thus allowing the choice of area for installation of the rainwater storage system.