PROJECT DESCRIPTION
BACKGROUND
Waste heat recovery in industrial processes is a broad and well-known topic, but only solutions at low/middle temperature in ‘clean’ conditions can be considered sufficiently mature for widespread use. This means that only a very small fraction of the energy consumed is re-used by industry, while the remainder needs to be cooled down before being released into the atmosphere.
In energy intensive industries, most of the waste heat streams are difficult to recover. Some studies have calculated that the potential energy savings from these industries could reach 15.4% of the total energy lost, which is significant in the case of the steel industry (accounting for almost 30% of the total EU industrial heat consumption).
This project builds on tests carried out from 2015 to 2019 under the H2020 ReSlag project and which highlighted the positive thermophysical properties of the steel slag and its potential for use as Thermal Energy Storage (TES) material. A TES system could thus covert intermittent and non-homogeneous exhaust gases stemming from the Electric Arc Furnace into a continuous and homogeneous source of useful energy that can be managed on demand for scrap pre-heating and self-power supply. The advantage of this project is thus also the reduction of slag wasted that needs to be landfilled or self-stored.
OBJECTIVES
LIFE HI4S aims to develop and validate an innovative cost-effective combined heat and electricity production plant from the waste heat contained in the off-gas of an electric arc furnace within the steel making industry. This waste heat re-use plant will employ a TES system based on the steel slag generated in the steelworks, and will save around 37.5 GWhe /year. The TES will be used for scrap pre-heating and self-power supply.
The project is in line with the priorities of the Green Deal for full economic decarbonisation; it encourages disruptive technologies with a high potential for improving energy efficiency, especially in energy-intensive industries that generate large amounts of waste heat. The project also promotes the circular economy industrial policy.
RESULTS
Expected results:
- Energy saving of 4.9% of the total electricity required in the electric arc furnace (400 KWhe/t steel);
- Reduction of total steelwork CO2eq emissions in steelworks by 6%; and
- Reduction of slag waste by 10-15%, with the valorised steel slag offering a potential source of income.
