Decarbonising Steel: Carbon Capture of Blast Furnace Gas through Chemical Absorption

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Decarbonisation of the iron and steel industry is essential in the pathway to net zero carbon emissions and the minimisation of climate change effects. Most of the world's steel is produced via the blast furnace-basic oxygen furnace route, with a majority of the steelmaking emissions coming directly from the blast furnace. Currently, there is limited knowledge concerning the application of chemical absorption techniques of CO2 removal to blast furnace gas (BFG), with existing research mostly focussed on simulation and modelling studies. Research involving pilot-plant experimental campaigns or larger applications have either used monoethanolamine (MEA) as the traditional baseline solvent or have used commercial propriety solvents with limited information publicly available. Further work is also under investigation for improved performance of these capture plants through structural modifications, the majority of which is also constrained to simulation studies.The main aims of this project are to:Investigate CO2 capture from blast furnace gas by chemical absorption at pilot scaleImprove and optimise the performance of the pilot plant based on process modificationsTo achieve these above aims, four objectives have been outlined that will be investigated for this project and help to form the major research chapters in the final thesis publication.1. Assessment of chemical absorbents for CO2 capture from a typical blast furnace gas composition at a pilot scaleThis objective will utilise the chemical capture plant at the Translational Energy Research Centre (TERC) in Sheffield to perform a series of experiments using BFG. Different solvents will be tested and compared to MEA as the baseline. Performance metrics include: CO2 recovery/purity, reboiler temperature and duty, solvent flowrate.2. Investigation of alternative configurations of the TERC capture plant for improved performance through simulation and modellingTo assess different configurations of the existing TERC capture plant, simulation will be undertaken using Aspen Plus. A model of the existing base capture plant will be created and validated using existing data, against which alternative configurations will be assessed. This modelling work will fill a niche area for chemical absorption improvement due to the novelty of working with BFG.3. Performance evaluation of the structurally modified TERC capture plant with different chemical absorbents in a pilot-plant experimental campaignFollowing objective 2, the next thing is to see which structural modifications can be realistically applied to the physical TERC capture plant. This will not be simple and may be restricted due to funding and/or time constraints. However, the plan is to investigate selected modifications in a pilot-plant experimental campaign for improved BFG clean up. Ideally this will also include the use of alternative solvents, depending on the number of modifications made. Practical data will be different to the data obtained from simulation and modelling, so it is important to assess how close the data corroborates and investigate why any major differences occur. 4. Investigation of full-scale chemical absorption for BFG clean-up through a modelling and simulation study based on scale-up from the TERC capture plantPilot-scale data is useful to assess the feasibility, practicality and economics of scaling up to full-size systems. This objective will take what has been learned in the previous objectives in order to model a full-size capture plant to deal with BFG. Practically, this work would guide the designs for full-scale up capture plants, as they have to be based on tangible performance data. By combining both simulated and practical work from the TERC capture plant, the full-scale up model should have a good standing as a comprehensive design for a real capture plant.