Nevertheless, the industry is taking steps to improve its eco-credentials, employing a range of innovative technologies to reduce the environmental impact of steel production.
The heat is on
One example of this is the use of Organic Rankine Cycle (ORC) turbines at the Ori Martin steel plant in Brescia in northern Italy, which produces hot-rolled steel for the mechanical and automotive industries. During summer operations, the ORC system generates enough energy from waste heat to meet the electricity consumption needs of 700 local families. In winter, the waste heat is used to heat up 2,000 households through the local district heating network.
This reduces the factory’s carbon footprint by 10,000 tons of CO2 a year, as well as eliminating the need for water-cooling.
The heat recovery system, which have been installed by a third party, and the ORC turbine, which have been installed by Mitsubishi Heavy Industries Group company Turboden, capture the exhaust gases and turn them into electrical energy and thermal power. They are based on the conventional steam turbine systems found in power plants. Instead of generating steam from water, however, the ORC system vaporizes an organic fluid. This not only removes the need for water, it also enables the turbines to run at lower speeds and pressures – using less energy – while minimizing metal erosion. It’s a low-cost system requiring limited maintenance, which doesn’t need a qualified operator as it runs automatically.
The circular economy
Recycling is another way in which the steel industry can contribute to a cleaner and more sustainable future.
Steel in itself is 100 percent recyclable. It can be used repeatedly without loss of integrity. The industry has long been taking advantage of this by using scrap steel as an additional element in the steel making process, forming a circular loop where nothing is wasted.
But steel production generates high volumes of waste materials like dust, fines and mill scale, all of which need to be handled and disposed of effectively. And by-product recycling solutions are one way to convert residual production materials into a useful and profitable resource.
At Ori Martin in Brescia, for example, the dust accumulation and by-products of manufacturing are recycled. The plant is also fitted with a high-temperature water recycling circuit to avoid wasting water used for cooling steel bars as they emerge from the foundry.
Adopting such a resource-efficient approach to manufacturing is not only economical, but also lowers the industry’s impact on the environment.
Clearing the air
In addition, steel companies are also finding ways to literally “clean up” their production process to meet increasingly stringent environmental protection regulations.
For every metric ton of steel produced, 10 to 25 kilograms of dust accumulates, which then enters the atmosphere through production exhaust air.
Gas cleaning is a highly efficient dedusting solution that cleans dust from exhaust air and keeps production within strict pre-set emissions limits. A reliable dedusting system lowers operating costs and helps make the steel production process more sustainable.
Tomorrow’s steelmakers will be smarter
Technological advances are boosting the industry’s efficiency in other ways, too. The fourth industrial revolution is allowing technology to work in ever-closer harmony with different aspects of metals production, transforming the way steel is made.
As well as converting traditional production environments into highly automated “smart” plants, digitalization enables the different parts of the steel manufacturing process to interact and perform at their full potential.
A digitalized plant’s production management systems use sensor technology, digital production planning tools and sophisticated AI-driven diagnostics to monitor each smart component. Output is optimized for maximum overall performance and, as part of this process, each function within the plant is continually analyzed and refined for incremental improvements in efficiency.
Future systems will use machine learning to discover the optimum way to produce steel with minimum resources.
This article originally appeared on Forbes