International Journal of Greenhouse Gas Control 5 (2011) 1199–1205 Contents lists available at ScienceDirect International Journal of Greenhouse Gas Control journal homepage: www.elsevier.com/locate/ijggc Chemical looping combustion for power generation—Concept study for a 10 MW th demonstration plant Klemens Marx ∗ , Johannes Bolhàr-Nordenkampf, Tobias Pröll, Hermann Hofbauer Vienna University of Technology, Institute of Chemical Engineering Getreidemarkt 9, 1060 Vienna, Austria article info Article history: Received 25 May 2010 Received in revised form 20 April 2011 Accepted 6 May 2011 Available online 15 June 2011 Keywords: Chemical looping combustion Power generation Process simulation IPSEpro abstract A semi-commercial 10 MW th chemical looping combustion (CLC) plant for power production is proposed as a next scale demonstration plant after successful operation of a 120 kW CLC pilot rig. The design criteria for the CLC boiler are derived from the experience obtained from the CLC pilot rig at Vienna University of Technology. The IPSEpro simulation environment is chosen for implementation of the process flow sheet of the CLC power plant. A single pressure steam cycle is suggested for this small scale demonstration plant. Heat exchangers and a five-stage steam turbine are arranged. Basic design parameters of the power plant are derived from detailed mass and energy investigations and discussed. It turns out that the net electric efficiency of such a small scale plant can be expected to be in the range of 32.5–35.8%. However, a demonstration of CLC at such a scale is necessary in order to gain confidence in more sophisticated CLC power generation concepts at larger scale. © 2011 Elsevier Ltd. All rights reserved. 1. Introduction To tackle the problem of increasing carbon dioxide concentra- tion in the atmosphere the key mid-term strategy is carbon capture and storage [1]. One promising novel technology for carbon capture is chemical looping combustion (CLC). Chemical looping systems consist of two reaction zones in which different gas streams are in contact with circulating solids. The circulating solids are metal oxide particles which transport oxygen from an air reactor (AR) to a fuel reactor (FR), and thus the fuel reactor exhaust gas consists ideally only of CO 2 and H 2 O (see Fig. 1). After water condensa- tion a highly concentrated CO 2 stream ready for sequestration is obtained. This technology was first introduced in 1954 [2]. Later the pro- cess was proposed by Richter and Knoche [3] and Ishida et al. [4] to increase the reversibility of combustion processes. In 2004 first reports were presented from a 10 kW CLC unit oper- ated with gaseous fuels at Chalmers University in Sweden [5,6], and later in 2004 Ryu et al. [7] reported from a 50 kW CLC unit at the Korean Institute of Energy Research. In January 2008 a 120 kW CLC pilot plant was put into operation at Vienna University of Technol- ogy. A detailed description of the plant can be found in an article by Kolbitsch et al. [8] and operation experience with different bed materials can be found in Pröll et al. [9], Kolbitsch et al. [10], and Bolhàr-Nordenkampf et al. [11]. ∗ Corresponding author. E-mail address: Klemens.Marx@tuwien.ac.at (K. Marx). The experiments verified the potential of the CLC technology. Thus, the next step in process development is to demonstrate this technology in an industrial size application. First, basic design parameters of a CLC boiler at the scale of 10 MW th were calculated by Lyngfelt et al. [12] in 2001. The design criteria were chosen for an atmospheric circulating fluidized bed (CFB) boiler with a bubbling bed as FR in the return loop of the CFB. The boiler concept proposed by Lyngfelt et al. [12] is used for heat production, district heating, or production of industrial process steam. In contrast to the design proposed by Lyngfelt the design of the CLC pilot rig at Vienna University of Technology has certain advan- tages mentioned by Kolbitsch et al. [8]. In this paper basic design parameters for a 10 MW th CLC boiler for power generation based on the dual circulating fluidized bed (DCFB) design of the 120 kW pilot rig in Vienna are presented. 2. The dual circulating fluidized bed (DCFB) boiler The chemical looping boiler assessed in the present work is a DCFB system for gaseous fuels. The general setup is shown in Fig. 2. The boiler design is based on the Vienna 120 kW pilot rig which was designed with a direct focus on scalability to larger size. The design consists of two interconnected CFB’s. Loop seals (LS1 and LS2) between the reactors fluidized with superheated steam con- nect the reactors and avoid mixing of AR and FR gases. The flow regimes are fast fluidization in the AR and turbulent fluidization in the FR. Downstream of each reactor, gas and solids are separated in cyclone separators. More specific details about the DCFB system can be found elsewhere [8]. 1750-5836/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.ijggc.2011.05.012