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2015-10-19 - Colloque/Présentation - communication orale - Anglais - 2 page(s)

Dubois Lionel , Laribi Sinda , Meunier Nicolas , De Weireld Guy , Thomas Diane , "Global optimization of the CO2 capture and reuse applied in the cement industry" in Brussels Sustainable Development Summit 2015, Brussels, Belgium, 2015

  • Codes CREF : Traitement des effluents gazeux (DI3843), Génie chimique (DI2721), Chimie (DI1300)
  • Unités de recherche UMONS : Génie des Procédés chimiques et biochimiques (F505), Thermodynamique, Physique mathématique (F506)
  • Instituts UMONS : Institut de Recherche en Energétique (Energie)

Abstract(s) :

(Anglais) The reduction of the CO2 emissions from different industries (power plants, cement plants, etc.) at world scale requires the implementation of Carbon Capture, Storage and Utilization (CCSU) processes. The application of CCSU to power plants flue gases (CO2 contents from 5% to 15%) has already been considered in many studies but there is still a lack of data concerning its specific application to the cement industry. Regarding the capture phase, two technologies are adapted to the cement industry, namely: the post-combustion CO2 capture (currently tested at pilot scale in the cement industry), where the CO2 in the pretreated flue gas (containing from 20% to 30% CO2) is conventionally captured thanks to an absorption-regeneration process where it is absorbed in a solvent (such as monoethanolamine 30 wt.%) which is then regenerated requiring energy, and the oxy-fuel combustion (the selection of a cement plant for pilot tests is undergoing), where the combustion is performed with pure oxygen leading to flue gases highly concentrated in CO2 (>80%) which need to be purified (de-SOx, de-NOx, etc.) prior to conversion into valuable products such as methanol. Another option envisaged by the cement industry is the “partial oxy-fuel combustion” which corresponds to the combination of the combustion with O2-enriched air (CO2 contents in the flue gas between 40% and 60%) and post-combustion CO2 capture by the absorption-regeneration process. In this context, the ECRA (European Cement Research Academy) Academic Chair was established at UMONS in 2013, focusing on the CO2 capture and reuse applied to the cement industry. The present communication will give a global overview of all the ECRA Academic Chair research activities and will present the first relevant results in relation with the optimization of the CO2 capture and conversion steps. As illustrated on Fig. 1 the optimization of the absorption-regeneration CO2 capture process applied to cement flue gases includes both experimental (lab scale and micro-pilot scale tests [1-3]) and simulation (with Aspen HysysTM, using the parameters coming from [4] and considering different process configurations) works. The second aspect of this work is the study of an entire process chain, from the oxy-fuel cement kilns to the conversion into methanol (see Fig.2). Simulations of the CPU (CO2 Purification Unit) were carried out and highlighted that an efficient removal of SOx and NOx compounds is achievable. The catalytic conversion of purified CO2 coming from the investigated purification process into methanol was simulated using Aspen PlusTM, based on the kinetic data from the works of [5] using CuO/ZnO/Al2O3-type catalysts. Fig. 1. Methodology applied for the optimization of the absorption-regeneration CO2 capture process applied to cement flue gases Fig. 2. Illustration of the global process chain including CO2 purification and conversion steps Globally, this work confirms that the post-combustion CO2 capture process applied to both conventional and partial oxy-fuel combustion cement kilns can be optimized thanks to the use of adequate solvents (increasing the absorption performances) and process configurations (reducing the energy consumption of the process from 3.7 GJ/tCO2 to less than 2.5 GJ/tCO2). Other solvents and process configurations are still under investigations. Regarding the oxy-fuel combustion cement kilns, it was shown that thanks to optimized purification and conversion processes, the techniques conventionally envisaged for power plants are applicable to cement plant flue gases. First simulation results show that up to 99% of the CO2 entering the unit can be converted into methanol producing a stream with a methanol concentration of 60 wt% which must be further distilled to produce a rather pure methanol flow. An experimental test rig is under establishment to study the effect of SOx and NOx compounds on the catalysts performances which will be useful to optimize the entire process and to define the CO2 purity level needed for an optimal conversion into methanol. Finally, this work aims at proposing a fully-integrated and optimized process including pre-treatments units of flue gases issued from cement plants, CO2-capture units, and CO2-conversion reactors investigating also different CO2-reuse possibilities.