CHEERS or Chinese European Emissions Reducing Solutions is an international R&D project, funded partially by the European Union (Horizon 2020- Research and Innovation programme), to demonstrate a second generation carbon capture and storage (CCS) technology at relevant size, taking it up to technology readiness level (TRL) 7. The key deliverable of this project is to design, construct and operate a chemical looping combustion 3MW demo unit and validate with pet coke and lignite feedstock. 

The webinar held on the 25th of January 2023, moderated by Ana Serdoner from Bellona Europa, hosted all the actors of the consortium. European partners represented by Sintef, Total Energies, IFP Energies Nouvelles, Bellona and Silesian University of technology, while the Chinese partners were represented by Dongfang Boiler group, Tsinghua University and Zhejiang University. The presentation touched upon various aspects, updating the processes and methodologies undertaken as well as the key technical takeaways from the project. 

 Scope of Work Packages:

Stephane Bertholin from IFP Energies Nouvelles kicked off the discussion by setting the scope of the work package, highlighting the objectives: provide techno-economic assessment of the industrial Chemical Looping Combustion- Carbon Capture and Storage (CLC-CCS) unit, address different design cases relevant for industrial needs and Benchmark CLC technology including full CCS chain and Life Cycle Analysis (LCA) perspectives. 

The work package was split into 3 phases: the first being the modelling of the reactor at industrial scale which was completed over 2018 and 2019. The second being the process simulation carried out over 2019 and 2020. The final phase being the Techno-economic study carried out from the data gathered from process simulation, concluded in 2021. 

 Reactor modelling:

Nicolas Vin from IFP Energies Nouvelles dove deeper into the strategy of realizing a reactor model. The first model was initially developed from studies available at IFP EN, used to validate operation based on experimental results. Further the model was upgraded to an industrial scale and hydrodynamic models were added. The final step, validation of the demo unit itself, is yet to be done. 

The modelling was done using both a batch unit as well as a continuous unit, allowing for the study of parameters such as temperature, CO2 content etc. as well as pet coke and oxygen flowrates. The modelling held up against the experimental results, to which Nicolas Vin notes “it means the physics is well represented [in the model]”.   

 Process Simulation:

Moving on the process simulation of the industrial scale model Catherine Laroche from IFPEN highlighted the two uses cases that the simulation tested: power generation (200MWe) and refinery (50MWe). “We decided to have two design cases in order to assess the performances of the process at two different scales” says Catherine. 

As the CLC reaction with inputs such as pet coke generates a lot of heat, there is significant steam that can be used to generate electricity. Two different reference CCS combustion plants were used to benchmark the CLC plant. The first, a natural gas combined cycle plant, the second a circulated fluidized bed plant, both using standard amine based capture technology. The natural gas plant considered both Mono ethanolamine (MEA) and an advanced solvent Piperazine/2-amino-2-methyl-1-propyl (PZ/AMP) while the second only looked at MEA. The demo reactor unit (3MW) is representative of these two references in size, nearly matching its height, but differing significantly in width.  

Elaborating on efficiency, Catharine compared the outputs of a 200MWe power plant with the different benchmarks. The thermal power efficiency of the CLC plant sits between the Circulating Fludised Bed (CFB) and Natural Gas Combined Cycle (NGCC) plants, but the net electric efficiency lagged behind both in the simulation. However, the high capture rate of 97% in the CLC plant results in a CO2 emissions factor of 29 kgCO2/MWhe, significantly lower than both NGCC and CFB plants. The amount of CO2 captured for storage is also higher in CLC and CFB plants compared to NGCC due to the nature of carbon content in pet coke as compared to natural gas. These aspects point to the conclusion that CLC would be the preferred technology when pet coke is used as fuel due to higher net power efficiency, lower specific emissions and higher capture efficiency.  

 Techno-economic assessment:

Vincent Gourand from Total Energies touched upon the economics of the CLC plant and the full chain through the techno-economic assessment. “To get the best and most accurate techno-economic assessment, we wanted to have the best figure for the CAPEX and OPEX. We selected a few companies to get quotes for different parts of the CLC.”, he says. 

Starting with the CO2 flue gas treatment, which constitutes 20% of CAPEX of total plant costs, the technology is oxy combustion which results in very little nitrogen that needs to be separated and is a highly concentrated stream of CO2, making capture easier and cheaper.  

Vincent presented several Key Performance Indicators (KPIs) based on the established hypothesis that the plant would consider 2019 prices. The first KPI presented was the levelized cost of electricity, putting the CLC plant at around 100 euros/MWh not considering transport and storage costs. Compared to the reference technologies, this places CLC Levelised cost of energy (LCOE) lower than that of CFB but higher than that of NGCC. By including price sensitivity of natural gas in the NGCC plant (an increase of 50%), the LCOE of the NGCC plant climbs higher than the CLC case.  

The second KPI discussed was the cost of avoided CO2 (euro/tco2). For the power generation study, the CLC case fared significantly better compared to CFB reference, with CLC placed at 98.5 euro/tco2 avoided, whereas the CFB case rose to 254 euro/tco2 avoided. NGCC reference technology fared slightly better with and without capture compared to the CLC case. For the refinery study, the results were similar, the only difference being that the costs rose significantly for both CFB and CLC cases (379.5 and 184.8 euro/tco2 respectively). The third KPI presented was the net present value and cost of avoided CO2 in the refinery case. Here, like in the previous case, CLC performs better than CFB case but falls short of the NGCC case significantly.  

A couple of sensitivity analyses were introduced as well, for the power generation case, the oxygen carrier sensitivity was evaluated using mineral oxygen carriers (usually cheaper) and synthetic oxygen carriers and the inventory change over specific time periods. The second sensitivity introduced was the capture rate. Decreasing the capture rate (by reducing the efficiency of the carbon stripper) of the CLC plant does not greatly impact the cost of avoided carbon. 

Simon Roussanaly from SINTEF touched on more of the economic aspects of both power generation and refinery cases. The sensitivity due to fuel prices was checked, benchmarked against NGCC case. Ranging the 2019 price of gas by 50% on either side and pet coke price by 100% on either side. The matrix so formed shows the diagonal on which it makes more economic sense to opt for CLC over NGCC, requiring significant reductions in pet coke price and increase in natural gas prices. Moving on to the costs associated with the CLC and NGCC cases, the LCOE and Net Present Value (NPV) pointed to higher values for CLC due to larger volumes of CO2 to be captured and transported. This alludes to lower residual emissions for the CLC case. 

Considering the full chain of CCS, the costs affect the matrix formed by the fuel price sensitivity. It reduces the available range of fuel cost considerations that allow CLC to be economically more viable than the NGCC case for the power generation case. For the refinery case, the window for CLC to be economically viable shrinks further.  

Moving to the conclusions, Simon summarized the caveats, for a solid feedstock such as pet coke, CLC fares far better than CFB with carbon capture for both power and refinery case. NGCC is mostly a better option compared to CLC, especially in the refinery case, with the comparison becoming competitive only due to price sensitivities and reduced distance to storage sites.  

 Life Cycle Analysis:

Elodie Gaouyat from Total Energies elaborated upon the life cycle analysis of the CLC project. In particular, the evaluation loops to check the environmental performance of chemical looping combustion process to produce electricity in comparison with CFB and NGCC with carbon capture. The LCA takes a cradle to gate approach with the functional unit of 1kWh of electrical power and does not include the use of produced electricity nor the transportation or storage of CO2. 

The LCA shows a 43% reduction in GHG emissions in the CLC case compared to the CFB, with 66% if emissions in CLC case due to pet coke. These reductions are proportional to capture rates; higher the capture rate, higher the reductions. Despite high capture rates, CLC still fares worse compared to NGCC. The other environmental impacts place CLC above CFB but in general, NGCC fares the best. Regarding other environmental impacts, CLC still requires increased mineral resources such as CACO3 and water due to use of ammonia. 

The webinar concluded with interesting questions raised by participants resulting in engaging conversation with the presenters.