A Ca-Cu Chemical Loop Process for CO2 Capture in Steel Mills: System Performance Analysis

12 Pages Posted: 2 Apr 2021

See all articles by Syed Zaheer Abbas

Syed Zaheer Abbas

The University of Manchester

Panagiotis Alexandros Argyris

The University of Manchester

José-Ramón Fernández

Spanish Research Council CSIC-INCAR

Juan Carlos Abanades

Spanish Council for Scientific Research (CSIC)

Vincenzo Spallina

The University of Manchester

Date Written: April 1, 2021

Abstract

The conceptual design and modelling of the Calcium Assisted Steel-mill Off-gas Hydrogen (CASOH) process for the conversion of blast furnace gas (BFG) into H2-rich stream and CO2-rich stream at a large scale is discussed in this work. High temperature reactors packed with CaO- and Cu-based materials are used to remove CO2 from the gaseous phase and simultaneously shifting the WGS equilibrium towards H2-rich products. The incorporation of a Cu/CuO chemical loop to such sorption process allows an efficient regeneration of the CO2 sorbent. In this case, the heat needed for the calcination of the CaCO3 is supplied in situ by the exothermic reduction of CuO to Cu with a gaseous fuel (e.g. CH4, CO or H2). The Cu-based solid is firstly converted to CuO(s) during the oxidation step with air and later reduced during the regeneration step, which involves the combination of the endothermic reaction of CaCO3(s) calcination and the exothermic gas-solid reduction of CuO(s) to Cu(s) using a gaseous fuel (typically BFG or natural gas producing a highly concentrated stream of CO2 and H2O(v)).

In this paper, the three reaction stages of the CASOH process are modelled with a new 1-D reactor model that integrates state of the art kinetic information on the gas solid reactions, predicting the molar composition of the product gases (dry basis) at the outlet of the packed-bed reactor and maximum temperature achieved in each stage.

The 1-D reactor modelling results confirm that process allows the conversion of up to 99% of the inlet CO to H2 at intermediate temperatures (about 650 °C), because of the efficient and continuous removal of CO2 from the gas phase. The high pressure (10 bar) during the Cu-oxidation step causes a very low leakage of CO2 (1.1 vol. %) due to the partial calcination of CaCO3, i.e. only 8 wt. % of the CaCO3 is calcined in this stage. Finally, the feed of BFG as reducing gas during the regeneration stage leads to a maximum temperature of 850 °C in the bed, which allows the complete calcination of the sorbent and gives as a result a CO2-rich stream ready for purification and subsequent use or storage.

Keywords: CO2 capture; hydrogen; steel mill; chemical looping combustion; calcium looping

Suggested Citation

Abbas, Syed Zaheer and Argyris, Panagiotis Alexandros and Fernández, José-Ramón and Abanades, Juan Carlos and Spallina, Vincenzo, A Ca-Cu Chemical Loop Process for CO2 Capture in Steel Mills: System Performance Analysis (April 1, 2021). Proceedings of the 15th Greenhouse Gas Control Technologies Conference 15-18 March 2021, Available at SSRN: https://ssrn.com/abstract=3817401 or http://dx.doi.org/10.2139/ssrn.3817401

Syed Zaheer Abbas (Contact Author)

The University of Manchester ( email )

Booth St West
Manchester, N/A M15 6PB
United Kingdom

Panagiotis Alexandros Argyris

The University of Manchester ( email )

Booth St West
Manchester, N/A M15 6PB
United Kingdom

José-Ramón Fernández

Spanish Research Council CSIC-INCAR

Francisco Pintado Fe 26
Oviedo, 33011
Spain

Juan Carlos Abanades

Spanish Council for Scientific Research (CSIC) ( email )

28006 Madrid
Spain

Vincenzo Spallina

The University of Manchester ( email )

Booth St West
Manchester, N/A M15 6PB
United Kingdom

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