Commissioning of a New Trl7 Pilot to Investigate the Decarbonization of Blast Furnace Gases Using a Packed Bed of Ca-Cu Solids

Abstract

This work outlines the commissioning activities and the first experimental results obtained in a new pilot that has been built at the Arcelor Mittal Gas Lab (Asturias-Spain) to decarbonise up to 300 Nm3/h of Blast Furnace Gas from a nearby steel mill. This work is part of the EU funded C4U project that intends to demonstrate at TRL7 the Calcium Assisted Steel-mill Off-gas Hydrogen (CASOH) process to decarbonise Blast Furnace Gases. The CASOH process relies on high-temperature solid looping reactions carried out in a series of packed-bed reactors that continuously switch between three main reaction stages. In a first stage (also called CASOH), there is carbonation of CaO by the capture of CO2, including the CO2 generated by the catalysed Water Gas Shift (WGS) of the CO present in the BFG. Subsequently, the second reaction stage involves the oxidation of the WGS Cu-based catalyst with air. The third and final stage features the exothermic reduction of the CuO with a fuel gas, which results in the decomposition of CaCO3 and the generation of a concentrated CO2 gas stream, while regenerating the CaO used in the first reaction stage. The reaction stages of the CASOH process have been experimentally validated at TRL4 within the C4U project, using commercially available Ca and Cu materials, which are also being used for the TRL7 demonstration. The results showed in this work refers to examples of successful reaction stages of the CASOH process. The first experimental campaign has been carried out under dynamic conditions with a limited quantity of Ca/Cu materials in the bed of solids (about 200 kg of mixed solids using CaCO3 provided by Carmeuse and Cu-supported catalyst supplied by Johnson Matthey). With this load of solids, a 1-meter high reactive bed is achieved (out of the reactor’s total capacity of 5 meters), which is sufficient to build confidence in the operation of the pilot plant and to confirm that each stage of the CASOH process can be successfully carried out under the expected operating conditions. The pilot is intended for use in future projects exploring advanced versions of the CASOH process and other high-temperature solid looping processes utilizing packed bed reactors

Keywords: CO2 capture in steel sector, calcium looping, chemical looping, BFG decarbonisation, CASOH

JEL Classification: Q53,Q54,Q55