Carbon Dioxide Adsorption from Refinery Flue Gases

Abstract

Increasing awareness of the in uence of greenhouse gases on global climate has led to recent e orts to develop strategies for the reduction of carbon dioxide (CO2) emis- sions. Fossil-fueled power plants are responsible for roughly 40 percent of total CO2 emissions, coal- red plants being the main contributor. International Panel on Cli- mate Change (IPCC) predicts that, by the year 2100, the atmosphere may contain up to 570 ppmv CO2 against its present stage (389.91 ppmv), causing a rise of mean global temperature of around 0.9 °C and an increase in mean sea level of 0.38 m. In 2000, the burning of coal generated 37.8% of all CO2 arising from fossil fuels [1] and as a result the strategy that is receiving the most attention involves the capture of CO2 from large point sources (such as fossil fuel- red power plants). In the his- tory of civilizations, worldwide CO2 emissions are increasing trend due to the rapid industrialization. The greenhouse gas can then be stored long term, either under- ground or in the ocean. However, to economically transport and store CO2 it must be in a relatively pure high pressure form, requiring the separation and compression of CO2 emitted by the power plant. The CO2 capture step is projected to account for the majority of the expense for the overall carbon capture and subsequent storage process. There are three options to reduce CO2 emissions into the atmosphere: To reduce energy intensity, to reduce carbon intensity, and to capture and store CO2. The rst two options require e cient usage of energy and a switch to non-fossil fuels such as hydrogen and renewable energy respectively. The third option requires the development of new e cient technologies for CO2 capture and sequestration (CCS). The main application of CO2 capture is likely to be at fossil fuel power plants, re- neries, cement industries, which are contributing a large extent of CO2 emissions into the atmosphere. To date, all commercial CO2 capture plants based on chemical absorption with an aqueous alkanolamine solvent of which monoethanolamine (MEA) is the most pop- ular [2]. However, regarding their application to ue gases, these technologies need vi signi cant modi cation to take care of high energy consumption and associated cor- rosion in presence of oxygen in ue gas. These ultimately lead to high capital and running costs. Therefore, although amine technology could be suitable for ue gases, the development of alternative low cost technologies could be crucial in the long term to provide a more cost and environmentally e ective route to carbon capture and storage on a global scale. Adsorption is considered to be a promising technology for the e cient capture of CO2 from ue gases. To overcome the problems associated with current CO2 capture techniques, this project involves the creation of a new generation of adsorbents - solids that can soak up CO2 - to be used in power plants/ re nery. The adsorbents work on the principal that CO2 is a weak acid that can be trapped onto a solid base with the right characteristics and well-developed pore-structure [3, 4]. Solid inorganic adsorbents will be created using support materials with numerous active sites to soak up CO2. Adsorption capacities as a function of adsorbent properties, adsorbent loading, and

ue gas compositions are described.