OVERVIEW OF THE ZECA (ZERO EMISSION COAL ALLIANCE) TECHNOLOGY

We discuss a novel, emission-free process for producing hydrogen or electricity from coal. Although we focus on coal, the basic approach is compatible with any carbonaceous fuel. The process uses cyclical carbonation of calcium oxide to promote the production of hydrogen from carbon and water. The carbonation of the calcium oxide removes carbon dioxide from the reaction products and provides the additional energy necessary to complete hydrogen production without the need for the combustion of carbon. The calcination of the resulting calcium carbonate is accomplished using the high temperature waste heat from solid oxide fuel cells, which generate electricity from hydrogen fuel. Converting waste heat back to useful chemical energy allows the process to achieve very high conversion efficiency from fuel energy to electrical energy. As the process is essentially closed-loop, the process is able to achieve zero emissions if the concentrated exhaust stream of CO{sub 2} is sequestered. Carbon dioxide disposal is accomplished by the production of magnesium carbonate from ultramafic rock. The end-products of the sequestration process are stable, naturally-occurring minerals. Sufficient high quality ultramafic deposits exist to easily handle all the world's coal