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Biomass combustion ash in carbon capture

In June 2019, the UK government declared a climate emergency and announced a target of net zero greenhouse gas (GHG) emissions compared to the 1990 emission levels by the year 2050. However, in order to effectively minimise and control the rise in global temperature to below 2 °C, negative emission technologies such as biomass energy with carbon capture and storage (BECCS), are recognised to be vital to meet the Paris Agreement climate targets, as stated in the 2018 Intergovernmental Panel on Climate Change (IPCC) report.

Despite promises for mitigating large volumes of CO2 and despite governmental incentives and regulatory drivers, the high cost of CCS (primarily from capture and compression, accounting for 75% of the total cost of CCS) has largely impacted its large-scale deployment.

Therefore, alternative economically-feasible processes with minimum environmental footprints must be developed, urgently. Adsorption for CCS is an attractive second generation technology for a number of reasons; importantly, it can be retrofitted to any power plant should the adsorption column be optimised to ensure acceptable footprint and cost.

Biomass combustion is accompanied by the generation of a large quantity of solid waste residue: bottom ash (BA) and fly ash (FA). A significant portion of this residue is currently being directly landfilled with no further useful application. With an anticipated increase in biomass combustion in the UK (e.g. Drax power plant, UK, has just converted 4 out of its 6 boilers to biomass), the co-generation of this solid residue will present an additional challenge for waste management, creating a great opportunity for exploring potential re-use of this increasingly available solid waste in the future.

Owing to the unique alkaline nature of biomass combustion ash (BCA) and its chemical properties, BCA could find niche applications in CO2 capture. Compared to coal fly ash, the elevated alkaline contents in biomass ash can make this type of ash more efficient in CO2 capture compared to coal ash. Therefore, investigations into the potential utilisation of BCA is not only environmentally beneficial but also of high economic and social significance, especially in the context of the UK economy with an ever-increasing interest in biomass combustion. High performance modified BCA could be a great competitor with the conventional and novel adsorbents such as activated carbons, zeolites and metal organic frameworks (MOFs) due to their low-cost, abundance and the possibility of in-situ applications at biomass combustion facilities.

In this research work, we are investigating the performance of raw and modified BCA as adsorbents in post-combustion CO2 capture. The industrially-generated biomass combustion ash will be chemically modified and characterised using a range of standard techniques. The equilibrium and kinetics of the adsorption process will then be studied using thermogravimetric methods. The effects of the operational parameters such as inlet gas flow rate, CO2 partial pressure and inlet gas temperature on breakthrough curves, pressure drop and mass transfer rates, will be studied on a lab-scale fixed-bed reactor.

This study has been supported by the UK Carbon Capture and Storage Research Centre (UKCCSRC) flexible funding research grant. The UKCCSRC is supported by the EPSRC as part of the UKRI Energy Programme.

Meet the Principal Investigator(s) for the project

Dr Salman Masoudi Soltani - I am a Senior Lecturer (Associate Professor in the US system) in Chemical Engineering. In May 2017, I joined Brunel University London as a founding member of the new Chemical Engineering Department, on the team in charge of the design and development of the Programme. I did my BSc (2005), MSc (2008) and PhD (2014; University of Nottingham) in Chemical Engineering. I am a Chartered Engineer (CEng/MIChemE) with both industrial and academic research backgrounds in chemical and process engineering. I am also a Fellow of Higher Education Academy (FHEA), UK, and the Postgraduate Research Director with the Department of Chemical Engineering.  My research area is mainly centred on Separation Processes (with a focus on adsorption processes), and Process Modelling & Design. I am currently leading a number of major research projects on and around carbon capture and hydrogen production, funded via Engineering and Physical Sciences Research Council (EPSRC), UK Carbon Capture and Storage Research Centre (UKCCSRC), and the Department for Business, Energy & Industrial Strategy (BEIS), along with a number of industrial consultancy projects, the details of which have been included under the "Research" tab of this profile. Before joining Brunel University London, I worked as a Postdoctoral Research Associate with the Department of Chemical Engineering (Clean Fossil & Bioenergy Research Group) at Imperial College London, UK (07/2015 – 05/2017), contributing to several EPSRC as well as EU- and OECD-consultancy projects (Opening New Fuels for UK Generation; Gas-FACTS; CO2QUEST) in the realms of biomass combustion and the modelling and optimisation of CO2 capture & utilisation processes - in Professor Paul Fennell's research group and in collaboration with Professor Niall Mac Dowell and Professor Nilay Shah. In March 2017, I received the prestigious endorsement as the Exceptional Talent in Chemical Engineering by the Royal Academy of Engineering, UK. Prior to this, I worked as a Postdoctoral Knowledge Transfer Partnership Research Associate with Dr Shenyi Wu (Fluids and Thermal Engineering Research Group) at the University of Nottingham, UK (08/2013 – 07/2015), during which, I was fully based at A-Gas International ltd. production site in Bristol (UK), where I worked as a Project/Process Engineer on a major joint engineering research and process design project, involving the research, front end engineering design (FEED), detailed design, and development of a bespoke industrial-scale gas separation process. I was awarded The University of Nottingham Scholarship to study for a PhD in Chemical Engineering. I conducted my research with the Department of Chemical & Environmental Engineering at the University of Nottingham, Malaysia Campus where I studied the effects of pyrolysis conditions on the structure of porous carbonaceous adsorbents synthesised from recycled waste, and the effect of subsequent surface modification on heavy metal removal from aqueous media.

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Project last modified 13/10/2021