*5.4. Cement Plants*

To evaluate the impact of process decarbonization (in a post-combustion capture configuration) for cement production, the next plant concepts were considered as illustrative examples:

Case 4.1—Conventional cement production plant without decarbonization;

Case 4.2—Decarbonized cement production based on reactive gas-liquid absorption (MDEA);

Case 4.3—Decarbonized cement production based on reactive gas-solid system (CaL).

As presented in Table 1, a conventional cement plant was considered in the assessments with 1 Mt/y production capacity [4]. For decarbonized cement production cases by reactive gas-liquid and gas-solid systems, a coal-based combustion unit in conjunction with a steam cycle power block was used to cover the ancillary energy (heat and power) consumptions of the carbon capture plants [38]. The excess energy was exported as the power to the grid with a 520 kg/MWh as the carbon dioxide emission factor. The most relevant techno-economic and environmental performance indexes of the assessed cement plants are exhibited in Table 6.


**Table 6.** Cement plants techno-economic and environmental performance indexes.

As presented in Table 6, the cement plant decarbonization cut significantly the overall carbon footprint of the process (by about 92–93%). The investigated looping cycle exhibits several benefits in comparison to the chemical scrubbing system, e.g., higher energy conversion yield and subsequent lower decarbonization energy penalty. Another important element of the calcium-based reactive gas-solid system refers to the potential to reuse the spent solid material in the cement plant (clinker production). This element brings advantages in terms of reducing carbon footprint as well as improving technical and economic performance indicators [39]. As for the above-presented cases, the decarbonization process brings a positive effect in reducing the carbon footprint, but on the other hand, increases other environmental indicators [40].

Decarbonization of the cement production process brings significant economic penalty (74–112% increase of specific capital investment, 62–95% increase of cement production cost). The economic indicators show that calcium looping option has better economic performance than post-combustion capture in term of specific capital investment (reduced by about 18%), cement production cost (reduced by about 16%), and CO2 avoided cost (reduced by about 34%).
