Hydrogen Breakthrough Ironmaking Technology (HYBRIT)

HYBRIT is a joint venture between SSAB (steel producer), LKAB (mining company) and Vattenfall (energy company), formed originally in 2017. In this project, a semi-industrial scale pilot plant for direct reduction of iron ore was built in Luleå (Sweden). It has led to the production of sponge iron (DRI /HBI) using fossil-free hydrogen since 2021. The H2 is produced using alkaline electrolysers. The H2 has also been used to develop a technology for underground storage in lined rock caverns.

TECHNICAL DESCRIPTION
Large part of the HYBRIT development work has been carried out in facilities that correspond to full-scale industrial production in terms of both equipment and process control, but with a lower production capacity. Each process step in the HYBRITs process chain has been investigated (including the fossil free production of iron ore in a direct reduction process using only hydrogen, the melting of fossil free iron in an EAF, the production and storage of fossil free hydrogen and electrical heating of hydrogen. The key innovative elements of the HYBRIT initiative are summarised below.

Direct reduction with fossil-free hydrogen to produce sponge iron (DRI and HBI)
• The pilot plant for direct reduction in Luleå was commissioned and started operation in 2020 using only natural gas. The direct reduction plant operated without an external reformer (Energiron type). During the first period of operation, different process settings based on natural gas were tested leading to a wide range in product quality (in terms of carbon content and degree of metallisation) of the produced DRI and HBI. The process settings and the products have since then been used as a reference to the developed hydrogen-based technology. The produced sponge iron has been analysed in different ways to understand the properties and some selected materials have also been melted in electric arc furnace trials.
• Since 2021 the direct reduction pilot plant has been operated using only hydrogen as reduction gas. Different ways of carburising the sponge iron have been tested and the produced DRI and HBI has been characterised to evaluate the different properties compared to the natural gas-based sponge iron. The use of hydrogen in the reduction gas leads to fundamental changes in the thermodynamics and the chemistry of the process compared to conventional natural gas-based process. The objective of the development program has been to develop optimal process conditions (in terms of energy) and product properties (in terms of yield) as design basis for the scale up of the process to industrial practice.
• The direct reduction plot in Luleå has a capacity of 0,8 to 1,4 t DRI/h and is run under continuous operation 24/7, for testing periods of 4-8 weeks. When calculating different process point up to end of 2023, 175 has been evaluated during different campaigns in the pilot and more than 5000 ton of sponge iron has been produced. Some of the DRI and HBI have been further evaluated and used for melting trials in the pilot EAF.
• Sponge iron pellets reduced with hydrogen with a high degree of metallisation (98-99%) in the HYBRIT pilot plant appeared to be significantly better in terms of transport, storage and melting properties than sponge iron reduced with natural gas. In particular, the mechanical properties of sponge iron reduced with hydrogen and with 0 % carbon shows that the material can be handled and stored for a long time (slow ageing) in a safe way. In addition, the increased strength of the sponge iron leads significantly to less losses during handling. The sponge iron produced using hydrogen has shown to be more resistant to mechanical pressure, abrasion and drops and the energy consumption in the melting step is less for this product with a high degree of metallisation. Through drop tests realised at 10 and 30 meters, the highly metallised DRI product reduced with hydrogen showed that only a few percent of the material broke down into pieces less than 6,3 mm after 10 drops from 10 or 30 meters drop height. Those results are better than other industrial reference tests.
• The heating of the reduction gas requires a rather high amount of energy to increase the temperature of the gas to a high enough temperature to do the reduction work in a sufficient way. Different heating techniques has been evaluated in the HYBRIT pilot plant including gas fired heating with natural gas, biogas and hydrogen together with different electrical heating installations also in combination with oxygen injection to boost the reduction gas temperature to higher levels. The span of the reduction gas temperatures evaluated in the pilot operation ranged from 550 to 1090 ⁰C.

Melting of hydrogen reduced DRI and HBI in electric arc furnace
• The process has been verified on a pilot scale by melting HYBRITs sponge iron in Swerim´s 10-tonne electric arc furnace at SWERIM facility in Luleå.
• To minimise the electricity consumption and maximise energy efficiency and productivity, biocarbon and oxygen are added, which together with the slag form an emulsion, a so-called foaming slag.
• The development has been carried out by testing a variety of raw material properties, additive methods, process configurations and process settings.
• An example of varied parameters of iron carriers is sponge iron (DRI) and compacted sponge iron (HBI). Different adding methods has been tested as continuous feeding and batchwise. The iron carriers have had different chemical properties as carbon content and degree of metallisation.

Underground storage of hydrogen in lined rock caverns
• HYBRIT has developed a technology for underground hydrogen storage in a lined rock cavern. The pilot program has entailed the design, construction and operation of a pilot-scale hydrogen storage facility with a capacity of 100 cubic meters, containing hydrogen pressurised up to 25MPa, situated 30 meters below the ground surface in Svartöberget, Luleå.
• The design concept has already been demonstrated on an industrial scale for natural gas in Skallen, Sweden. The technical development has been based on the existing knowledge however adapted for hydrogen, especially in terms of material selection.
• The hydrogen storage facility opens up the possibility to adapt hydrogen production to the price of electricity while meeting the hydrogen needs of the reduction process. This creates the conditions for cost-effectively managing fluctuations in the supply of renew-able electricity. High pressure is required for the storage to be efficient and by constructing underground, this pressure is generated by the rock mass instead of by heavy pressure vessels above ground. Results from trials at the pilot plant show that storage can reduce the variable cost of hydrogen production by up to 40%.
• The scope of using the hydrogen storage with the fluctuations in the electricity market means that the storage needs to be filled and emptied with a higher frequency and speed compared to if the storage is used for natural gas. The higher flexibility in storage also means that the hydrogen production needs to be adaptable for this purpose with a flexible production capacity.

DEGREE OF MATURITY
The development work has been conducted in pilot plants specifically designed to mimic a full-scale industrial process but with a lower production capacity. The developed technologies have all been tested in a relevant environment (up to TRL 6/7) and has been operated during different test campaigns since 2020 (Direct reduction and melting) and 2021 (hydrogen storage).

A full scale HYBRIT plant is going to be built in Gällivare (North Sweden). The plant is foreseen to operate at full industrial scale in 2027. It will result in the avoidance of 14.3 million tons of CO2 over the first 10 years of its operation. It will need around 5TWh/year of fossil-free electricity. Besides, a new, first-of-a-kind hydrogen production facility will also be established using a 500 MW electrolyser capacity powered by fossil-free electricity. The plant will be located in an industrial park where DRI will be used for production of steel slabs after melting in EAF.

Basic information about the technique

Participant Companies