Carbon Capture Via Chemical-Looping Combustion and Reforming

INTERNATIONAL SEMINAR ON CARBON SEQUESTRATION AND CLIMATE CHANGE Rio de Janeiro 24 – 27 October 2006

Carbon Capture via Chemical-Looping Combustion and Reforming

Marcus Johansson1, Tobias Mattisson2, Magnus Rydén2 and and Anders Lyngfelt2

1

Department of Chemical and Biological Engineering, Division of Environmental Inorganic Chemistry 2 Department of Energy and Environment, Division of Energy Technology, Chalmers University of Technology, S-412 96 Göteborg Sweden

Abstract

Chemical-looping combustion (CLC) is a combustion technology with inherent separation of the greenhouse gas CO2. The technique involves the use of a metal oxide as an oxygen carrier which transfers oxygen from combustion air to the fuel, and hence a direct contact between air and fuel is avoided. Two inter-connected fluidized beds, a fuel reactor and an air reactor, are used in the process. In the fuel reactor, the metal oxide is reduced by the reaction with the fuel and in the air reactor; the reduced metal oxide is oxidized with air. The outlet gas from the fuel reactor consists of CO2 and H2O, and almost pure stream of CO2 is obtained when water is condensed. Considerable research has been conducted on CLC in the last decade with respect to oxygen carrier development, reactor design, system efficiencies and prototype testing. The technique has been demonstrated successfully with both natural gas and syngas as fuel in continuous prototype reactors based on interconnected fluidized beds within the size range 0.3 – 50 kW, using different types of oxygen carriers based on the metals Ni, Co, Fe, Cu and Mn. From these tests it can be established that almost complete conversion of the fuel can be obtained and 100% CO2 capture is possible. Further, two different types of chemical-looping reforming (CLR) have been presented in recent years. CLR is a technology to produce hydrogen with inherent CO2 capture. This paper presents an overview of the research performed on CLC and CLR highlights...