Some technical issues of zero-emission coal technology

A concept of zero-emission coal technology, proposed by ZECA Corporation, is presented and discussed. The process can produce electricity at 60-70% efficiency with zero emission to the atmosphere. The carbon dioxide is produced as concentrated, clean stream, which is easy to sequestrate. The process uses CaO/CaCO3 reaction to enhance hydrogen production and to separate carbon dioxide. Hydrogen feeds a stack of solid oxide fuel cells (SOFCs), which produce electricity. High-temperature byproduct heat from the SOFC drives the calcination reaction, which restores CaO. Unfortunately, the possible realization of the process may encounter various technical difficulties mainly connected with requirements for the SOFC (very high operating temperature, high sulfur tolerance, integrated heat exchanger) and CaO/CaCO3 process (the decrease of the performance with increasing number of cycles and problematic heat transport into calcination vessel). (c) 2005 Intemational Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.