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Energy & environmental care papers will be presented by Primetals Technologies specialists at the ESTAD Congress covering the topics of energy recovery and the recycling of carbon emissions from steelworks.
Integrated Energy Recovery and Utilization of Waste Heat for Integrated Plants and the EAF Route
Principal author: Paul Trunner
Paper number: 261
In order to determine the most feasible solution for increasing energy efficiency in a steelworks, a holistic understanding of all processes in the steel production chain is required. In integrated iron and steel production sites, energy from waste heat sources such as the coking plant, the sinter plant, the converter cooling stack and reheating furnaces can be recovered and efficiently used elsewhere within the plant. Many opportunities to improve energy efficiency in EAF-based steel mills can also be identified. By combining multiple sources of waste heat from, for example, a direct-reduction plant, the hot exhaust gases from the EAF and the reheating furnace, sufficient energy can be retrieved to economically generate electrical power, steam or hot water for heating purposes as well as to produce chilled water by means of absorption heat pumps. Different possibilities for energy recovery and utilization for integrated steelmaking and electric steelmaking process routes are discussed. A focus is also placed on the economic feasibility of energy-saving systems in steel mills.
The Circular Economy: Carbon Recycling and the Steel Industry
Principal author: Dr. Alexander Fleischanderl
Paper number: 292
Recycling carbon emissions from steel mills offers an important new source for fuels and chemicals production while simultaneously reducing the carbon footprint of a steel mill. The watchword is circular economy. Carbon-rich gases should be recycled wisely when the use of carbon is unavoidable, such as for the production of chemicals, fuels and plastics. However, for the generation of electric- ity, sustainable solutions exist that include wind, solar and hydropower to substitute the combustion of carbon-rich gases.
A new development in offgas recycling substantially improves a steelmaker’s economic competitiveness. LanzaTech’s microbial fermentation of carbon- and hydrogen-rich offgases – such as coke oven gas, blast furnace top gas, direct-reduction gas and converter gas – can be applied to produce ethanol or other basic chemicals. The result is a major reduction of CO₂, NOx, SOx and particulate emissions to the environment. The fuels and chemicals produced in this manner deliver superior economic returns. Compared with conventional gasoline, when ethanol is used as a fuel blend up to 70% less greenhouse gases are emitted. The technology is ready for commercial implementation.