Decarbonization of Blast Furnace Gases Using a Packed Bed of Ca-Cu Solids in a New TRL7 Pilot

This work outlines the commissioning and initial experiments from a new pilot plant at Arcelor Mittal Gas Lab (Asturias, Spain) designed to decarbonize up to 300 Nm3/h of blast furnace gas (BFG). This investigation intends to demonstrate for the first time at TRL7 the calcium-assisted steel-mill off-gas hydrogen (CASOH) process to decarbonize blast furnace gases. The CASOH process is carried out in packed-bed reactors operating through three main reaction stages: (1) H2 production via the water–gas shift (WGS) of the CO present in the BFG assisted by the simultaneous carbonation of CaO; (2) oxidation of the Cu-based catalyst with air, and (3) reduction of CuO with a fuel gas to regenerate CaO and produce a concentrated CO2 stream. The first experimental campaign used 200 kg of commercial Ca- and Cu-based solids mixed to create a 1 m reactive bed, which is sufficient to validate operations and confirm the process’s effectiveness. A product gas with 40% of H2 is obtained with CO2 capture efficiency above 95%. Demonstrating at TRL7 the ability to convert BFG into H2-enriched gas with minimal CO/CO2 enables remarkable decarbonization in steel production while utilizing existing blast furnaces, eliminating the need for less commercially developed production processes.