Mass recirculation is an approach that can substantially enhance CO2 capture and fuel conversion processes in energy generating systems. The current review investigates significant patented developments utilizing mass-recirculating systems in air-fuel, oxy-fuel and membrane-assisted CO2 capture technologies over the last 10 years (2000-2009). Main specific objectives and roles of mass recirculation in variety of power generating systems with CO2 avoidance are expounded with focus on the enhancement of existing CO2 separations and fuel conversions. All searches are also directed at seeking for novelty aspects in different CO2 capture systems but having a common feature, i.e. utilizing an effective approach - mass recirculation. The paper is organized as follows. In section 3, available CO2 separation processes are briefly described, e.g. chemical absorption, cryogenic and membrane separation etc. In sections 4-5, the most important patents are briefly characterized in each of 5 selected categories. The effects of mass recirculation and combustion products enrichment on CO2 separation processes and reactions in fuel combustion and oxyforming are covered. The main benefits of mass recirculation are comprehensively presented in tabular form with respect to specific categories of disclosures. Finally, in section 6, a brief comment on the future directions of CO2 capture technologies with mass recirculation is provided.
CO2 capture, mass recirculation, fuel conversion, energy technology
Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland.