The energy efficiency and the environmental consequences of typical coal upgrading processes, such as combustion, depend to a large extent on the degree of gas separation, recovery and recycle. Among the available methods, used in chemical industry for a variety of gas separations tasks, the technology of polymer membranes offers several advantages such as low size, simplicity of operation and maintenance, compatibility and diversity. To examine the impact of membrane separation on coal upgrading processes, the ASPEN PLUS simulation software was used, in combination with the developed membrane mathematical models. Energy analysis in coal combustion processes, where the main scope is CO2 removal, showed that very promising results could be attained. It is estimated that 90% of the emitted CO2 can be captured with a moderately low energy penalty (10%). This penalty can be further decreased if higher selectivity and/or permeability polymers can be developed. In terms of CO2 sequestration, and through specific European projects, four of the most promising types of geological storage are being studied in various areas of Europe including Greece. These storage types include:
(i) onshore/offshore saline aquifers with or without lateral seal,
(ii) low enthalpy geothermal reservoirs,
(iii) deep methane-bearing coal beds, and abandoned coal and salt mines,
(iv) exhausted or near exhausted hydrocarbon structures