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Chinese-European Emission-Reducing Solutions

Periodic Reporting for period 2 - CHEERS (Chinese-European Emission-Reducing Solutions)

Reporting period: 2019-04-01 to 2020-03-31

CHEERS is a collaborative project between Europe and China that involves a 2nd generation chemical-looping technology currently tested and verified at laboratory scale (up to 150 kWth). Within five years, the core technology will be developed into a 3 MWth system prototype for demonstration in China. This constitutes a major step towards large-scale decarbonisation of industry, offering a considerable potential for next-generation industrial combustion processes.

CHEERS concentrates on chemical-looping combustion (CLC) aimed at providing a high temperature gas for steam generation with inherent CO2 capture. The technology requires two fluidised reactors, where solid particles are oxidised by air in one reactor before being transported to the other reactor and reduced by the fuel. The exhaust from the fuel reactor consists primarily of CO2 and H2O (as in traditional oxy-combustion schemes), while the exhaust from the air reactor is oxygen-depleted air. In refineries, the fuel could be either waste gases resulting from refining processes, heavy residual fuels, or petroleum coke. In addition, Chinese partners shall further test CLC for power generation purpose with lignite feedstock. This results in a larger impact of the CHEERS project thanks to implication of a wide range of partners.

The system prototype is based on a fundamentally new fuel-conversion process synthesised from prior research and development actions over more than a decade. The innovative concept is deemed capable of removing 96% of combustion-related CO2 while eliminating the CO2 capture energy penalty to almost zero. The captured CO2 stream can then be sent either for utilisation purposes or compression and storage.

Applied to industrial auxiliary systems, CHEERS aims at reducing drastically the efficiency drop lost to the CO2 capture chain. Hence, a reduction by at least 50%, from a current level of 9-10%-points, typical of absorption techniques, to less than 4%-points in power generation systems seems feasible. In steam generation systems, the gain is even larger, dropping from a level of 18-33% efficiency penalty with absorption techniques to a mere 2-3%-points with the new technology. This gain shall be demonstrated in operations using petroleum coke as the most challenging fuel. In this respect, CHEERS is conceived as a greening measure for the petroleum refining sector, converting petroleum coke and heavy residual oil into auxiliary steam and power. It is anticipated that a successful demonstration will pave the ground for a wider deployment of the technology in the energy-intensive industry, especially processes hampered with combustion-related CO2. In addition, combustion of biomass in a CLC system can produce renewable electricity or heat with negative CO2 emission.
In CHEERS, the verification of oxygen carriers is an integrated activity. Oxygen carriers should be capable of sustaining the exceedingly high sulphur and metals contents associated with petcoke. Petcoke conversion is challenging due to low volatility, which makes petcoke less reactive than most solid fuels. The interaction between oxygen carriers and the petcoke gasification/burn-out is vital to the process efficacy. This interaction may also cause critical agglomeration and sulphur passivation. So far, a first oxygen carrier (natural ore) has been selected and tested at pilot scale (up to 150kWth). The test results are promising, and a large batch of this oxygen carrier has already been shipped to the test site in China for further testing. The synthetic CMTF perovskite produced by SINTEF MK as part of the project showed very high stability and good performance for fuels with no sulphur. This OC can be favourable for fuels such as e.g. biomass and lignite. It cannot be taken further within this project but may be relevant in other projects undertaken by the partners. Work on a third oxygen carrier is currently ongoing.

The design of the entire 3MWth demonstration unit, based on a retrofit of an existing circulating fluidised bed (CFB), has been completed. With this design at hand, a technical comparison between retrofit and grassroot alternatives has been made. The conclusion of the comparison is that the grassroot alternative is the preferred option. In addition, a cold-flow mock-up of the demonstration unit has been designed, constructed, tested and used for further design validation and training of operators. In particular, hydrodynamic studies of the air reactor, L-valves and sections of the fuel reactor were performed and found to fit with design expectations. Based on this, the pre-FEED for the grassroots alternative, including cost estimations both for CAPEX and OPEX, is now finalized. The FEED call for tender and selection is nearly finished.

Several modelling approaches are being developed for the demonstration unit. A simplified one-dimensional model will be used for system optimization, while a full three-dimensional CFD model will be used to understand the behaviour inside the reactors in more detail. CFD simulations of the 150-kW pilot have been performed and the results show good match with the experimental data. The CFD models and simulation code promises to be a useful tool for analysing operation of a CLC system, providing insights into details that are very difficult or impossible to measure.

Performing a techno-economic study is an integrated part of the project. The design basis to be considered for the techno-economic study has been provided and an agreement has been reached about the reference cases to be considered.

The dissemination of results within the scientific community and the wider public have contributed to the increased visibility of Horizon 2020 projects and promoted cooperation between the EU and China.
During the second reporting period, CHEERS has progressed state of art within the understanding of pet-coke reactivity and its implications on oxygen carriers and their reactivity.

As the project continues, it is expected to demonstrate that an optimized chemical looping combustion technology can yield high CO2 capture efficiency at a very low efficiency penalty even for difficult fuels, such as pet-coke.

The expected impact of CHEERS are itemised as follows: (1) providing cost- and resource effective application of CCS in industrial operations, (2) constituting a stepping stone to wider deployment, (3) facilitating clusters of CCS projects, (4) ensuring a competitive position for existing EU industries in a future carbon-restrained world, and (5) reconciling competitiveness with EU climate goals.
Cold-flow mock-up