Calcium looping for CO 2 capture from a lignite fired power plant Ilias Vorrias a,b , Konstantinos Atsonios a,b,⇑ , Aristeidis Nikolopoulos a,b , Nikos Nikolopoulos b , Panagiotis Grammelis b , Emmanuel Kakaras a,b a Laboratory of Steam Boilers and Thermal Plants, National Technical University of Athens, 9 Heroon Polytechniou Street, 15780 Zografou, Greece b Center of Research & Technology Hellas/Chemical Process and Energy Resources Institute (CERTH/CPERI), Gr-15310, Greece highlights " Process optimization of the CaL technology in a lignite-fired power plant. " Fuel pre-drying and solids heat exchanger enhance the system efficiency. " CaL process has greater efficiency than MEA and oxyfuel. graphical abstract article info Article history: Received 29 September 2012 Received in revised form 24 December 2012 Accepted 31 December 2012 Available online 23 January 2013 Keywords: Calcium looping CO 2 capture Lignite power plant Supercritical cycle Post-combustion CO 2 capture abstract Calcium looping (CaL) process is considered as a competitive technology for the capture of CO 2 emitted from fossil fuel power plants. In this process two fluidized bed reactors are coupled. In the first reactor, i.e. carbonator, CO 2 is absorbed by CaO and CaCO 3 is produced, while in the second one, referred as cal- ciner, fuel is oxy – fired, so that calcium particles, already having absorbed CO 2 in the carbonator in order to produce CO 2 -rich flue gases, are regenerated. Numerous studies have focused so far on the implemen- tation of this process in coal fired plants. However, little work has been performed in terms of lignite fired plants. Thus here, the knowledge gaps are filled by means of a thorough investigation of the particular technology using a thermodynamic approach. It is worthwhile noticing, that the analysis is conducted on an existing lignite power plant, which is already operating and is located at the wider area of Meliti, Greece (330 MW e lignite fired power plant). For a more profound work, a series of parametric scenarios are investigated, for their optimum coupling setup, which subsequently lead to the conclusion that the energy penalty for the sorbent regeneration in cases of lignite combustion is higher than in cases of coal combustion. This is due to the higher moisture content and lower calorific value of lignite compared with coal. Finally, in order to achieve a lower energy penalty, several configurations are presented, resulting that the optimum is to burn pre-dried fuel, utilize solid heat exchanger and insert the fresh limestone inside the calciner instead of the carbonator. All configurations are evaluated in terms of CO 2 capture and net efficiency. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction According to Kyoto protocol and Copenhagen Accord [1], all industrialized countries are committed under binding obligations 0016-2361/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.fuel.2012.12.087 ⇑ Corresponding author at: ARKAT building, 357-359 Mesogeion Ave., Halandri, Athens, Greece. Tel.: +30 210 6501509; fax: +30 210 6527539. E-mail addresses: vorrias@certh.gr (I. Vorrias), atsonios@certh.gr (K. Atsonios), a.nikolopoulos@certh.gr (A. Nikolopoulos), n.nikolopoulos@certh.gr (N. Nikolopoulos), grammelis@certh.gr (P. Grammelis), ekak@central.ntua.gr (E. Kakaras). Fuel 113 (2013) 826–836 Contents lists available at SciVerse ScienceDirect Fuel journal homepage: www.elsevier.com/locate/fuel