Reduction of greenhouse gas emissions by integration of cement plants, power plants, and CO2 capture systems

Cement plants and power plants are two of the most significant sources of greenhouse gases emissions. Many CO2 reduction options have been proposed in literature for both sectors. They are mainly focused on CO2 capture in power plants, but, in the short-term, industrial processes are going to play an important role in achieving this objective. In particular, one of the disadvantages in cement plants is that CO2 has two sources: fuel combustion and lime calcination. For this reason, proposed solutions could partially reduce a limited quantity of emissions. The sector is forced to use CO2 capture systems for further reductions. Preliminary results about the implementation of post-combustion and oxyfuel combustion systems for CO2 capture show low energetic penalties and important emissions reduction. Nevertheless, a detailed analysis, not only of CO2 emissions, but of raw materials and its disposal, primary energy and waste energy, could give optimum results from an environmental, energetic, and economic perspective. The combination/integration by industrial symbiosis of a power plant, a cement plant and a CO2 capture system is proposed in this work. Calcium-looping is chosen as the most suitable CO2 capture option for this application. The re-use of waste CaO coming from CO2 capture in the cement plant, and the utilization of waste energy from a clinker cooling and capture system to produce additional power are the main advantages of this proposal. Process flow diagrams and heat and mass balances are calculated and presented in this work. Results show a low value of the CO2 avoided cost, 12.4 (sic)/t, that is smaller than in any other combination of power plant with capture system or cement plant plus capture system, making this proposal economically very attractive. Moreover, an important amount of CO2 emissions is avoided -94% - due to the energetic efficiency augmentation, the reduction of raw and decarbonizated materials, and the CO2 capture system. (c) 2011 Society of Chemical Industry and John Wiley & Sons, Ltd