Qualitative Comparison of On-Site Production of Hydrogen and Its Synthesis Products for Steel Processing Industry

Abstract

Decarbonizing high temperature heat in industrial processes is challenging as there are only few alternative fuels to reach the necessary temperatures. In steel mills the material must be heated up to 1250 °C before hot rolling of steel. Currently, this energy-intensive step is done in steel reheating furnaces fueled with natural gas. Synthetic fuels such as green hydrogen, synthetic methane and green ammonia are possible alternatives for substituting the current polluting energy carrier and in many future climate strategies considered as a crucial component for achieving greenhouse gas neutrality. In this paper, we present options for on-site production of synthetic fuels for steel mills and discuss them by a qualitative approach. Specifically, we investigate hydrogen, synthetic methane and ammonia. We consider state of the art technologies and apply them to a real-world use case from the steel processing industry in Austria. We point out the benefits of on-site generation of synthetic fuels as opposed to external supply in the case of steel mills. Depending on technology, we discuss possibilities for heat integration, implementation of carbon dioxide looping and efficiencies of the systems. We highlight the significant increase in the demand for electrical energy. Further, we discuss challenges of combustion in relation to nitrogen emissions, combustion behavior and effects on steel quality. Our results show hydrogen to be advantageous in many aspects when considering a fuel switch in steel mills with on-site generation. But also we identify synthetic methane as an interesting option that should be further examined.