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Steel production is a main source of CO2 emissions globally. These emissions must be drastically reduced to meet climate change mitigation goals. STEPWISE is a Sorption Enhanced Reactive Process (SERP) technology that converts steel works arising gases to H2 with simultaneous CO2 capture. The main energy requirements of the process are the high- and low-pressure steam quantities that are needed to rinse and regenerate the adsorbent. In this simulation study, the separation performance of STEPWISE is evaluated over a range of steam and feed pressure inputs by searching those design points where CO2 recovery and purity percentages are equalized. This method is used to facilitate the comparison of different operating regimes. Results highlight the importance of the rinse to purge ratio (R/P) as a design variable. A higher R/P ratio is demonstrated to maintain CO2 recovery and purity of ~95.5%, while total steam consumption and feed carbon loading are reduced by 27% and 20%, respectively. This is achieved without changing other parameters, like cycle time. Additionally, it is demonstrated that the CO2 capture performance can be maintained for varying feed pressure values by tuning the feed carbon loading. Future studies are recommended to focus on the expected role of the feed gas steam content on these findings.

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Reversible solid oxide cell (SOC) technology could enable efficient storage of renewable energy. In literature, reversible systems have not yet been widely investigated. The main goal of the present work is to address differences and similarities among simple SOFC and SOEC systems based on the same variables. Scope of the analysis is to identify useful operating regimes for a bi-directional system, using a thermodynamic analysis. Both energetic and exergetic point of views are adopted to estimate system and components performances. Preliminary results from the ongoing research are presented in this paper. Different operating conditions are evaluated via sensitivity analysis. Results are presented first for a reversible cell and then for a complete system. Looking at system operation it is feasible to design a reversible SOFC / SOEC system. At atmospheric pressure the total reversible system energy efficiency is around 30%. This value could be increased with system modifications.

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