Published: October 18, 2011 r2011 American Chemical Society 138 dx.doi.org/10.1021/ef201192n | Energy Fuels 2012, 26, 138–146 ARTICLE pubs.acs.org/EF Post-combustion Capture of CO 2 : Results from the Solvent Absorption Capture Plant at Hazelwood Power Station Using Potassium Carbonate Solvent Kathryn A. Mumford, † Kathryn H. Smith, † Clare J. Anderson, † Shufeng Shen, † Wendy Tao, † Yohanes A. Suryaputradinata, † Abdul Qader, † Barry Hooper, † Renato A. Innocenzi, ‡ Sandra E. Kentish, † and Geoffrey W. Stevens* ,† † Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC), Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia ‡ International Power Hazelwood, Melbourne, Victoria 3000, Australia ABSTRACT: Post-combustion capture of CO 2 from flue gas generated in a 1600 MW brown-coal-fired power station has been demonstrated using a solvent absorption process. The plant, located at International Power’s Hazelwood power station in Victoria’s Latrobe Valley, was designed to capture up to 25 tons/day of CO 2 (expandable to 50 tons/day of CO 2 ). The design of the capture plant was based on a proprietary solvent (BASF PuraTreat F). The main focus of this work, however, is to describe the performance of the plant using an unpromoted 30 wt % potassium carbonate (K 2 CO 3 ) solution. The CO 2 -capture plant was successfully operated using both BASF PuratTreat F and K 2 CO 3 , during which performance data were collected and analyzed. Although the plant only absorbed 20À25% of CO 2 from the flue gas when using the potassium carbonate solvent, valuable operating data were collected, which enabled process simulations to be compared to real plant data. Aspen Plus software was used to predict the performance of the plant while operating with potassium carbonate. In general, the model shows a slight difference (within (5%) compared to the pilot- plant results. This benchmarked model is an important part of the ongoing development of novel precipitating potassium carbonate processes for large-scale post-combustion CO 2 capture. 1. INTRODUCTION Solvent absorption is currently the preferred option for removing CO 2 from industrial waste gas and for synthesis and natural gas purification. This process involves passing the flue gas through a liquid that can absorb CO 2 (in an absorber vessel) and then release CO 2 at an elevated temperature in a regenerator vessel. Hot potassium carbonate solutions have been used commer- cially for acid gas absorption for many years. The process is commonly known as the Benfield process 1 and was originally developed by the U.S. Bureau of Mines in 1954 to reduce the costs of synthesis gas purification for the production of liquid fuel from coal. The process is designed for a gas process stream that has high temperatures and high partial pressures. Because of the high temperature and partial pressure in the absorber, it is therefore not necessary to further heat the solution to the stripping temperature required in the stripping process, rather a reduced pressure is used. This results in a lower process energy requirement and eliminates the need for heat-exchange equip- ment between the absorber and the regenerator columns. Furthermore, the operation at such high temperatures increases the solubility of the bicarbonate species; therefore, the Benfield process can operate with highly concentrated solutions. In more recent years, aqueous alkanolamines, such as mono- ethanolamine (MEA) or diethanolamine (DEA), have gained widespread attention for the capture of CO 2 . MEA is currently the lead technology but has several limitations. These limitations include the following: (1) Corrosion: resulting in the need for expensive materials of construction. (2) Amine degradation: high temperatures and oxygen act to degrade the amine, reducing its capacity to remove CO 2 . This results in a requirement for reclaiming equipment and solvent replacement. (3) Formation of heat-stable salts: amine can react irreversibly with minor gas components, forming heat-stable salts that can lead to solvent degradation and foaming problems. (4) Solvent losses: MEA has a high vapor pressure, which can result in high solvent losses in both the absorber and regenerator. (5) MEA has a relatively high energy requirement for regenerating the solvent in the stripping column, although it is currently the cheapest solvent available. For these reasons, a significant amount of research is being conducted to examine alternative solvents and processes. Potassium carbonate has a number of advantages over the amine-based solvents, with one of the most important being that absorption can occur at high temperatures, making the regenera- tion process more efficient and economical. Potassium carbonate also has a low cost, is less toxic, and is less prone to degradation effects that are commonly seen with amines at high temperatures and in the presence of oxygen and other minor gas components. The biggest challenge associated with using potassium carbonate as a solvent is that it has a low rate of reaction, resulting in poor CO 2 mass transfer. Promoters are often added to the solvent to Special Issue: 2011 Sino-Australian Symposium on Advanced Coal and Biomass Utilisation Technologies Received: August 4, 2011 Revised: October 16, 2011