Periodic Reporting for period 2 - CLEANKER (CLEAN clinKER production by Calcium looping process)
Période du rapport: 2019-04-01 au 2020-03-31
The cement industry is responsible for about 27% of global anthropogenic CO2 emissions from industrial sources worldwide and for 6 to 7% of global anthropogenic CO2 emissions. Cement manufacturing is CO2 intensive. Furthermore, most of cement-related CO2 emission (around 60%) is unavoidable, because it is generated during the calcination of limestone, the irreplaceable raw material needed to produce clinker. The residual 40% is associated to the combustion of fuels and to the production of electric power needed in the cement manufacturing process (from quarry to cement dispatch). The production of carbon neutral clinker is not feasible without the implementation of carbon capture systems. Calcium Looping (CaL) is a regenerative process that takes advantage of the capacity of calcium oxide-based sorbents to adsorb CO2 at high temperatures (600-700°C). The integrated CaL process is divided into two basic steps: (1) the limestone calcination is achieved in an oxy-fired reactor operating at 900-920°C, which makes the CaO available for both the rotary kiln and the CaL process, and releases a gas stream of nearly pure CO2; (2) the CO2 contained in the rotary kiln exhaust gases is separated by CaO conversion in a second reactor (carbonator) operating at 600-700°C. This highly integrated CaL process configuration enables CO2 capture with an efficiency target over 90% and high-energy efficiency. The overall energy consumption can be kept low by proper integration with raw meal preheating and heat recovery from the CO2-rich and CO2-lean flue gases.
The core activity of the project is the design, construction and operation of an integrated CaL demonstration system based on entrained-flow (EF) CaL reactors. The demonstrator is connected to the Buzzi Unicem kiln of the Vernasca cement plant (Italy). Other activities include: (i) screening of different raw meals to assess their properties as CO2 sorbent, (ii) reactors and process modelling, (iii) scale-up study, (iv) economic analysis, (v) life cycle assessment, (vi) CO2 transport, storage and utilization study, (vii) demonstration of the complete value chain, including mineral carbonation of waste ash with the CO2 captured in the pilot system, (viii) exploitation study for the demonstration of the technology.
The core activity of the project is the design, construction and operation of an integrated CaL demonstration system based on entrained-flow (EF) CaL reactors. The demonstrator is connected to the Buzzi Unicem kiln of the Vernasca cement plant (Italy). Other activities include: (i) screening of different raw meals to assess their properties as CO2 sorbent, (ii) reactors and process modelling, (iii) scale-up study, (iv) economic analysis, (v) life cycle assessment, (vi) CO2 transport, storage and utilization study, (vii) demonstration of the complete value chain, including mineral carbonation of waste ash with the CO2 captured in the pilot system, (viii) exploitation study for the demonstration of the technology.
The main objectives reached so far were the finalisation of pilot engineering (D2.2) the equipment construction and almost final erection (90%) of the demo system. Control strategies, safety analysis and risk analysis were also assessed (D2.5) giving to the operators the possibility to carry out the next experimental campaigns in a safe and flexible way. Internal meetings have been organized to provide technical insights for (i) solving some critical issues related to the erection works, (ii) defining secondary facilities, (iii) scheduling the experimental activity and (iv) developing a proper control logic for the correct operation of the plant.
Other CLEANKER activities included:
(i)Experimental characterization of reaction kinetics for different raw meals (D5.2): Vernasca and belitic raw meals were further experimentally studied to develop new kinetic models of calcination, carbonation, sulfation and belite formation, deriving useful parameters to support the modelling works.A random-pore model for carbonation kinetics, capable of predicting well the two carbonation rate steps (the fast carbonation and the diffusion controlled stage) as a function of temperature and of the raw meal structure was developed.
(ii)Test matrix for short tests has been developed D3.1. Short tests will evaluate the performances of the integrated demo plant as a function of the most significant CaL parameters and will be useful to define experimental matrix of the long-tests.
(iii)Heat and mass balances of the full scale integrated CaL plant have been calculated using in-house software (D5.8). A detailed sensitivity analysis on CaL parameters and carbonator geometry was carried out, obtaining promising results. The integrated CaL system was benchmarked against three different carbon capture technologies suitable for applications in cement industry. Heat and mass balances of the CO2 purification unit (CPU) have been calculated (D5.10). Two relevant configurations were simulated in both on-design and off-design operation.
(iv)New and revised dimensional models (1D-3D, see D5.4 D5.5 MS8) for the interconnected CaL reactors (EF calciner and carbonator) were developed exploiting the kinetics law obtained in WP4: the carbonation and calcination reaction rates of Vernasca raw meal is now included in the 1D and 3D routines, as well as the kinetics of belite formation.
(v)Design and commissioning of CO2 mineral trapping facility for mineralization tests in Vernasca (D7.5) that will exploit the most promising CaO-rich waste materials identified by TUT. The quality of the recarbonated wastes will be tested via concrete casting.
(vi)Methodology for techno-economic modelling of the Baltic and Italian CCUS scenarios: D7.1 and all the data for regional and local CCUS scenarios were collected (see MS13).
(vii)The screening of LCA was completed (D6.4) exploiting relevant data collected from literature and from the outputs of other WPs. The carbon footprint of the integrated CaL system was preliminary estimated and compared to the footprint of other carbon capture processes, showing that the CLEANKER technology has the potential of reducing the climate impact of cement production by 73%.
(viii)Equipment cost functions for the economic analysis of the full scale CaL system were defined in MS11. The cost function and the economic framework will be used for the development of the scale-up study.
(ix)Several dissemination and communication actions have been carried out during the second reporting period, to enhance the CLEANKER knowledge sharing.
Other CLEANKER activities included:
(i)Experimental characterization of reaction kinetics for different raw meals (D5.2): Vernasca and belitic raw meals were further experimentally studied to develop new kinetic models of calcination, carbonation, sulfation and belite formation, deriving useful parameters to support the modelling works.A random-pore model for carbonation kinetics, capable of predicting well the two carbonation rate steps (the fast carbonation and the diffusion controlled stage) as a function of temperature and of the raw meal structure was developed.
(ii)Test matrix for short tests has been developed D3.1. Short tests will evaluate the performances of the integrated demo plant as a function of the most significant CaL parameters and will be useful to define experimental matrix of the long-tests.
(iii)Heat and mass balances of the full scale integrated CaL plant have been calculated using in-house software (D5.8). A detailed sensitivity analysis on CaL parameters and carbonator geometry was carried out, obtaining promising results. The integrated CaL system was benchmarked against three different carbon capture technologies suitable for applications in cement industry. Heat and mass balances of the CO2 purification unit (CPU) have been calculated (D5.10). Two relevant configurations were simulated in both on-design and off-design operation.
(iv)New and revised dimensional models (1D-3D, see D5.4 D5.5 MS8) for the interconnected CaL reactors (EF calciner and carbonator) were developed exploiting the kinetics law obtained in WP4: the carbonation and calcination reaction rates of Vernasca raw meal is now included in the 1D and 3D routines, as well as the kinetics of belite formation.
(v)Design and commissioning of CO2 mineral trapping facility for mineralization tests in Vernasca (D7.5) that will exploit the most promising CaO-rich waste materials identified by TUT. The quality of the recarbonated wastes will be tested via concrete casting.
(vi)Methodology for techno-economic modelling of the Baltic and Italian CCUS scenarios: D7.1 and all the data for regional and local CCUS scenarios were collected (see MS13).
(vii)The screening of LCA was completed (D6.4) exploiting relevant data collected from literature and from the outputs of other WPs. The carbon footprint of the integrated CaL system was preliminary estimated and compared to the footprint of other carbon capture processes, showing that the CLEANKER technology has the potential of reducing the climate impact of cement production by 73%.
(viii)Equipment cost functions for the economic analysis of the full scale CaL system were defined in MS11. The cost function and the economic framework will be used for the development of the scale-up study.
(ix)Several dissemination and communication actions have been carried out during the second reporting period, to enhance the CLEANKER knowledge sharing.
Up to now, CaL has been extensively analysed and experimentally proven in the dual circulating fluidized bed configuration, used as a post-combustion capture system in coal-fired power plants and in cement plants. In general, there is a high-temperature solid looping cycles network (https://ieaghg.org/networks/high-temperature-solid-looping-cycles-network) that promotes further development and scale-up of processes for CO2 capture which involve solid looping cycles operating at elevated temperatures. The network is progressively expanding and moves rapidly through pilot and industrial demonstration. In this view, CLEANKER project is an example.
The CLEANKER system is based on entrained flow reactors, and exploits the conventional raw meal as CO2 carrier.
Potential impact of CLEANKER project is expected at different levels:
•Environmental and societal, through mitigation of climate change. The capture of 90% of CO2 is one of the most important CLEANKER target to be demonstrated during the experimental campaigns;
•Technical-scientific, through the creation of new knowledge both at experimental and modelling levels; obviously, the exploitation strategy of the project is influenced by the pilot operation.
•Social, through the increase of the public awareness on CCS and on sustainable cement production. For this purpose, different successful events have been organized, both with general public, local communities and local and regional administrations. The most important one is the opening event of the demonstrator, which has been postponed to Autumn 2020 due to the COVID-19 emergency.
The CLEANKER system is based on entrained flow reactors, and exploits the conventional raw meal as CO2 carrier.
Potential impact of CLEANKER project is expected at different levels:
•Environmental and societal, through mitigation of climate change. The capture of 90% of CO2 is one of the most important CLEANKER target to be demonstrated during the experimental campaigns;
•Technical-scientific, through the creation of new knowledge both at experimental and modelling levels; obviously, the exploitation strategy of the project is influenced by the pilot operation.
•Social, through the increase of the public awareness on CCS and on sustainable cement production. For this purpose, different successful events have been organized, both with general public, local communities and local and regional administrations. The most important one is the opening event of the demonstrator, which has been postponed to Autumn 2020 due to the COVID-19 emergency.