CO2 utilization from cement plant flue gas: Selection of suitable CO2 conversion routes for the cement sector, poster presentation

Carbon Capture Storage (CCS) or Utilization (CCU) are nowadays a well-studied and promising field in order to reduce CO2 emissions, main driver of global warming. CO2 utilization covers a large number of processes and chemical reactions that use CO2 as an alternative carbon feedstock. The CO2 can arise from a wide range of different sources including industrial flue gas, such as from power, cement or ammonia plants. In particular, CO2 emissions from the cement production represent approximately 5 to 7 % of anthropogenic global CO2 emissions. It is therefore an important task for the cement sector to reduce its emissions via different levers such as modern dry-process technology and carbon capture storage or reuse. Hence, the capture of CO2 from cement plants and its conversion into valuable compounds is a key issue to this sector.
As a multitude of processes and chemical reactions has been identified with different levels of maturity and performances, a two-step method is proposed to reduce this panel using selection criteria specially developed for this purpose. Therefore, the technological maturity of the conversion route, based on the so-called Technology Readiness Levels (TRL) and timeframe to deployment of the technology, is assessed through a review of CO2 usage activities around the world. In addition, a criterion evaluating the route potential to convert large volumes is relevant as a best available technology (BAT) cement plant emits around 2 500 tons of CO2 a day . A particular attention is also given to the origin of the production of co-reactants used through these processes, such as hydrogen, epoxides or minerals, in order to reduce the dependence on fossil feedstock. Following this, the second step involves further criteria, mainly based on economic and environmental aspects as well as market considerations, to assess the routes with the help of a weighting matrix specially developed. This second assessment helps to identify the CO2 conversion routes which are the most suitable to be implemented in the cement sector within a mid-term time period.
Several routes which mostly fulfill these above criteria are thus selected for in-depth analysis, such as the CO2-based production of methanol and methane via catalytic hydrogenation, or sodium carbonates through mineral carbonation.
An initial environmental assessment performed on these above selected products tends to demonstrate that their CO2-based production may have both lower emissions and potential to reduce fossil resource depletion than their respective classical production. An in-depth environmental evaluation, via the Life Cycle Assessment (LCA) method, is then required to evaluate their environmental impacts over a wide range of LCA impacts, to ensure the whole positive environmental balance. The CO2-based production of methanol from cement plant gases will be then assessed as a first case, regarding its advanced TRL.
Focusing on suitable CO2 conversion pathways through various criteria for the cement sector will help final decision makers to fit the roadmap for the cement sector to mitigate their contribution on global warming.