Decarbonisation Technology - February 2022 Issue

Realisation of a carbon negative combustor for gas turbines Gas turbines can be converted to carbon negative technologies using biomass energy combinedwith carbon capture and storage processes

Pietro Bartocci and Alberto Abad Instituto de Carboquímica (ICB-CSIC)

Biomass absorbs CO 2 during growth and releases it when burnt, but if the CO 2 is captured after combustion, this will result in a net flow of carbon out of the atmosphere. Thus, when bioenergy is coupled to CCUS, it is called bioenergy with carbon capture and storage (BECCS), which according to the Intergovernmental Panel on Climate Change (IPCC) report of 2014 is a negative emission technology (NET) (IPCC, 2014). This means that BECCS is able to remove CO 2 by the atmosphere. One of the most effective ways to couple biomass energy and CCUS is to burn biomass or biofuels (i.e. pyrolysis oils, biogas, and solid biomass) in a chemical looping combustor, where CO 2 can be easily captured after exiting the fuel reactor (see Figure 1 ). CLC uses an oxygen carrier based on a metal oxide to transfer oxygen to the fuel and obtains CO 2 in pure form inherently in the process. As CLC is not burdened with any separation work, it is particularly applicable for carbon capture and can achieve negative emissions when used with biomass. The social and economic impact of substituting current natural gas combined cycle power plants with GTCLC cycles is huge. In a study presented at the SDEWES Conference in 2020, we calculated that this project could be covered in part by the increasing carbon credit price and could generate at least 100,000 new jobs on a European level, solving a key problem for the gas turbine sector. GTCLC-NEG concept As well as being awarded a Marie Curie - Individual Fellowship, the GTCLC-NEG project has been funded by the European Commission (EU Horizon 2020 Framework Programme, Grant 101018576), with the Spanish National

Gas turbine sector evolution The power sector is undergoing rapid technological change. It is likely that conventional gas turbines will need to be integrated in systems employing biofuels and/or carbon capture usage and storage (CCUS) at competitive costs. The EU is moving swiftly towards low carbon technologies (such as energy efficiency, smart grids, renewables and CCUS) under the European Energy Union Strategy (European Commission, 2015). The development of carbon sequestration methods was identified by the US National Academy of Engineering ((NAE, 2017) as one of the ‘Grand Challenges for Engineering’. This technology was considered of paramount importance for the UN Sustainable Development Goals, SDG7 (Affordable and Clean Energy), and SDG5 (Climate Action).The Gas Turbine Chemical Looping Combustor for Carbon Negative Power Generation (GTCLC-NEG) project addresses two of the five pillars of the European Energy Union Strategy – renewable energy and CCUS – and couples these with breakthrough technologies, such as chemical looping combustion (CLC).

Condensed Captured HO CO

Depleted air

M x O y

Air reactor (oxidation)

Fuel reactor (reduction)

M x O y

Air

Fuel

Figure 1 Chemical looping combustion technology