Finding the Recipe for Hydrogen Heating

That’s exactly where our Engineering team is today, as we have been asked to design the world’s first full-scale 100% hydrogen-based iron reduction plant. Iron reduction with hydrogen has been done in a lab, and it’s been done with a very small-scale pilot plant, but no one to date has produced anywhere close to 2 million tons per year (Mt/y) of direct reduced iron (DRI) utilizing hydrogen as the sole reductant. H2 Green Steel is not far from doing just that in Boden, Sweden, with a first-of-a-kind “green steel” facility that includes a MIDREX H2^TM Plant.

The challenges of engineering this first-of-its-kind DRI plant are numerous and analogous to those that the early Midrex trailblazers faced in designing the first commercial MIDREX® Process plant in Portland, Oregon, in the late 1960s. They did not have the luxury of the depth of knowledge, expertise, and experience that we have today when they engineered those “miniscule” 0.15 Mt/y DRI modules. They also did not have the backing of our state-of-the-art Research and Technology Development Center that is located about 20 minutes away from the Midrex corporate headquarters. Our R&TD team has worked through many tests and trails to validate the assumptions that serve as the design basis for our approach to direct reduction utilizing a hydrogen-only reductant. The outcome of their work serves as a critical input to the multi-discipline team that is engineering the MIDREX H2 Plant.

Similar to the challenge of the development of the stoichiometric reforming system in the 1960s, one of our key challenges has centered around how to heat such an enormous flow of hydrogen reductant through a “green” energy source. Heating the hydrogen reductant through a hydrogen combustion system would be an obvious option, and a heating system similar to the design of a MIDREX Reformer would be a new application of a familiar and proven technology. But the combusted hydrogen would require additional electrolysis, and the loss in energy efficiency of the electrolysis process simply to burn the hydrogen product to produce heat begs for a better thermal solution.

Direct electrical heating provides the most efficient means to heat the hydrogen reductant. But a design for an electrical heater system with the capacity required for a 2 Mt/y MIDREX H2 Plant has only been a “high-class” wish, that is until Midrex and TUTCO Sure-Heat formed a partnership to jointly develop the world’s largest electrical heating system. Over the past year, Midrex and TUTCO SureHeat have been “in the kitchen” together, utilizing the expertise of both companies to design, analyze, and test a heater system. Our collaborative effort is proceeding to completion, and fabrication of the largest capacity electrical heating system in history will soon be underway.

Midrex made a giant “leap of faith” with the commissioning of the protype production plant in Portland, Oregon, to demonstrate the feasibility of producing DRI through a continuous, natural gas-based reforming process. When we start up the Boden plant with H2 Green Steel, we will be making another giant leap by demonstrating the capability of producing DRI without the by-product of carbon dioxide. Though similar, these processes have distinct differences, with the electric heating system being one of the biggest differentiators. It is truly exciting to see what Midrex and TUTCO Sureheat have conceived become a key ingredient in such a monumental change in steelmaking technology.

This issue includes a report on the collaboration of the Midrex Research & Technology Development Center and TUTCO Sureheat to design an electrical heater system for use in MIDREX H2 plants to prepare the hydrogen reducing gas, and an article by Primetals Technologies on the role of low-CO₂ hot briquetted iron (HBI) in helping to decarbonize steelmaking. In addition, News & Views announces the 2022 World Direct Reduction Statistics published by Midrex and the new office location of Midrex India and recognizes MIDREX Plants with start-up anniversaries in the third quarter.