Membrane properties required for post-combustion CO2 capture at coal-fired power plants

This paper focuses on the identification of membrane properties required to enable cost-competitive post-combustion CO2 capture from a coal power plant using membrane-based processes. In order to identify such properties, a numerical version of the attainable region approach proposed by Lindqvist et al., built as part of the of the iCCS tool developed by SINTEF Energy Research, is used to identify and assess the technical and cost performances of the optimal membrane process for a given set of membrane properties (selectivity and permeance). This numerical model is used to assess the cost performances of 1600 sets of membrane properties (selectivity and permeance) for post-combustion CO2 capture from a coal power plant as defined by the European Benchmarking Task Force and compare it with the reference commercial solvent concept (MEA) to identify the membrane properties required in a base case that treats both membrane- and MEA-based processes as mature and developed. The results show that to reach this competiveness with simple process configurations requires a permeance of at least 3 m(3)(STP)/(m(2).h.bar) with high selectivity, or alternatively a selectivity of at least 65 with high permeances. These limits can be reduced to permeances as low as 1 m(3)(STP)/(m(2).h.bar) with high selectivity, or selectivities as low as 30 with high permeances, when advanced membrane process configurations are being considered. The assessments of five additional cases quantify how additional costs associated with demonstration projects and higher membrane module costs can significantly increase the selectivities and permeances required to compete with MEA based capture. In order to link the membrane development works to the results presented in this paper, the constraint introduced by Robeson's upper bound limitation, as well as data available in the literature on membrane modules and polymeric materials, are compared with the results obtained. The inclusion of the upper bound shows that the capacity to generate thin membrane film layers is important in order to avoid reducing the range of membrane properties, in which diffusion governed membrane can be interesting in term of cost performances, especially in cases that take demonstration and/or higher module costs into consideration. The comparison with literature data shows that while several membranes and polymeric materials have the potential to be cost-competitive with further properties improvements, and once membrane-based CO2 capture becomes mature and demonstrated, financial support will be required to demonstrate and help mature the technology. Finally, ways to use the results presented here for membrane development by membrane development experts, for membrane selection by industrial users, and for technology development and demonstration support by decision-makers are discussed. (C) 2016 Elsevier B.V. All rights reserved.