CO2 Capture Technologies for Cement Industry.

Abstract: The effect of the increasing concentration of CO₂ in the atmosphere on climate change is a major driving force for the development of advanced energy cycles incorporating CO₂ management options. Growing interest in the technical and economic feasibility of CO₂ capture from large coal-based power plants has led to increased efforts worldwide to develop new concepts for greater CO₂ reductions in the future. Greenhouse gas emissions, especially CO₂, have to be reduced by 50–80% by 2050, according to the IPCC . The type of fuel used in cement manufacture directly impacts on CO₂ emissions, with coal accounting for around 60–70% of CO₂ emissions from cement installations. Therefore, the large amount of carbon dioxide emitted during cement manufacturing process - 5% of the total emissions of CO₂ from stationary sources worldwide - is a cause of great concern and has to be tack led in order to comply with current legislation. Several technologies are available and have been proposed for the separation of CO₂ from the flue gases from new and existing plants with retrofit capture units. Few studies have been undertaken on CO₂ capture in cement plants to assess the suitable technologies, with oxy-combustion and amine scrubbing as the possible options (pre-combustion capture not being viable). This paper summarises the different CO₂ capture technologies suitable for cement industry and assesses the potential of the calcium looping cycle as a new route for CO₂ capture in the cement industry. The potential advantage of this system is the very low efficiency penalty expected (<6%) compared with other capture technologies as the heat required for calcination is balanced by heat released during the carbonation (CO₂ capture) step and can be utilized efficiently at high temperature in the plant’s steam cycle. Since limestone is already used for cement manufacture, and because it is a cheap material with good geographical distribution, it allows the use of local limestone resources with minimal limestone-related infrastructure investment. Another envisaged benefit of this new technology is that the lime purged from the cycle could be us ed as a raw material for the production of cement clinker. Therefore, the calcium looping cycle can potentially have an important impact in reducing CO₂ emissions from the cement industry, and may also be applicable in other sectors. [Copyright &y& Elsevier]