Cement Energy Environment

9 The “Low-Carbon Transition in the Cement Industry”1 technology roadmap from the OECD / International Energy Agency has calculated that using new technologies such as carbon capture and storage or carbon capture and utilization would result in a substantial reduction of CO 2 emissions. An alternative solution for reducing emissions must be found. To this end, thyssenkrupp has been researching a new oxyfuel combustion process in which the combustion air is replaced by pure oxygen. The emissions would then almost completely consist of pure CO 2 and steam, thus radically simplifying the complicated separation process and enabling the CO 2 to be stored or processed. The first experimental plants for the cement industry in the USA and Europe were introduced from 2010, but the project has not yet moved beyond the experimental phase. Operators can retrofit their existing plants to the oxyfuel process. For older concepts (from around 2005 onwards), exhaust gas recirculation systems can be retrofitted to existing plants. This requires additional equipment, which in turn significantly increases the CO 2 as a reusable raw material A new combustion process Exhaust gas cleaning through Calcium looping “Innovative technologies including carbon capture (CO 2 emissions reduction of 48%) and reduction of the clinker to cement ratio (CO 2 emissions reduction of 37%) lead the way in cumulative CO 2 emissions reductions in cement making in the roadmap vision compared to the RTS by 2050.”2 complexity and the operating costs. Engineers at the research center of thyssenkrupp Industrial Solutions AG are therefore working on an improved process, and success is within reach. The new polysius® pure oxyfuel procedure uses pure oxygen as a combustion gas and does not require exhaust gas recirculation, thus significantly reducing the effort required to separate CO 2 . For all known CCS or CCU procedures, retrofitting represents a notable change in plant operation. thyssenkrupp Industrial Solutions is also researching processes to convert the separated CO 2 into reusable materials such as methane or methanol. Methane can be fed into the natural gas network, while methanol is a base for synthetic fuels such as kerosene. This process enables CO 2 to be used in a sensible way while also reducing the demand for fossil fuels. Note: Cumulative CO 2 emissions reductions refer to the period from 2020 to 2050 and are based on the low-variability case of the scenarios. Global cumulative CO 2 emissions reductions by applying the roadmap vision (2DS – 2 Degrees Scenario) compared to the RTS2 Alongside oxyfuel combustion and solvent-based separation after combustion, calcium looping is regarded as a further promising new technology for CO 2 separation in cement plants as it enables the utilisation of numerous energy and material synergies. Calcium looping is a regenerative process that uses the capacity of sorbents based on calcium oxide to separate CO 2 at high temperatures. Innovative technologies (incl. carbon capture) Reduction of clinker to cement ratio Fuel switching Thermal energy e ciency Electricity intensity 0 1,000 2,000 MtCO 2 3,000 4,000