(545j) Investigation on CO2 Capture and Utilization Using Simulated Bio-Gas and Extracted Metal Cations

Since Industrial Revolution in 18th century, the amount of energy usage by human-being have been drastically increased. The energy source that mostly used was fossil fuel. When fossil fuel is combusted, carbon dioxide is produced as a product. When carbon dioxide is emitted into the atmosphere in large amount, it may absorb the radiation energy emitted towards space from earth and reflect it towards the surface of the earth. In fact, there are six representative types of greenhouse gases (GHGs) including carbon dioxide (CO2), methane (CH4), nitrous oxides (NOx), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6). Among them, the global warming potential (GWP) of carbon dioxide is minimum, however, considering the portion in the total emission of GHGs, carbon dioxide is thought to be the main cause of greenhouse effects and climate change, furthermore. Hence, the technology to reduce carbon dioxide have been studied over a decade. One of the problem in common carbon reduction technology is that there are not enough spaces for its storage. So, the technology to utilize carbon dioxide after its capture had come arise. These technologies are commonly called Carbon Capture and Utilization (CCU). One of the method in this CCU technology is to convert carbon dioxide in to metal carbonate salt that can be used as raw materials in various industrial fields such as cement manufacturing industries, paper making industries and so on. The main research topic regarding this inorganic CCU is to secure metal cation supplying source in order to convert carbon dioxide into metal carbonate precipitate. The metal cation can be obtained from various sources: natural minerals, industrial wastes and seawater and so on. In this research, carbon dioxide is captured using alkanolamine based absorbents followed by carbon fixation using metal cation extracted from desulfurization ash produced from coal-fired powerplants. It is known that the main constituent of desulfurization ash is calcium sulfate. In common coal-fired powerplant which supplies electricity to metropolitan area, very large amount of desulfurization ash is produced every day and most of the facilities are suffering from the treatment of the ash. Using the calcium component contained in the desulfurization ash, calcium cation can be extracted using standardized method. As a result of the experiments, calcium carbonate precipitate was produced as final product. In order to investigate the type of substances, X-Ray Diffraction (XRD) analysis was performed. Also, to support its data, Scanning Electron Microscope (SEM) images were also obtained. Throughout the XRD and SEM analysis result, it is proven that the calcium carbonate in the crystal structure of calcite was dominant. Also, the absorption and conversion characteristics were demonstrated by suggesting carbon dioxide loading curve during absorption stage. The result and data obtained from this research may useful to process designing using industrial waste.