In chemical engineering, unit operation is the basic step in any separation process. Unit operation involves initiation of physical changes such as evaporation, crystallization, filtration, and separation among other physical processes. This paper involves a design of one operation unit for CO2 adsorption from flue gas of power plant.
The adsorption process would make use of activated carbon, a source mainly from fuel substances in the mining industry, and it will be based on physical adsorption mechanism. Physical adsorption involves electrostatic attractive interaction of opposite charges and the idea of weak Van der Waals forces. It is chosen over chemisorption process because it uses lower enthalpy of adsorption, which is between 8-20 kJ mol-1 against 40-800 kJ mol-1 for chemisorptions. While activation energy in chemisorptions is small, it is zero for the physical process. Another factor considered is the low temperature of occurrence in physical adsorption, which depends on boiling point. Physical adsorption also allows the application of more than one layer that is adsorbed while chemisorption allows the chance of only one layer.
Flue gas can be obtained from the combustion of a petroleum fuel such kerosene. The capture of carbon dioxide from power stations has increasingly become a key issue in research. CO2 separation is a benefit to the chemical industry, where CO2 is used for many purposes such as the production of methanol, urea, metal bicarbonates and carbonates. The concern on the production of CO2 is enhanced by the issue of global warming. Various capture approaches are typically applicable (Hicks et al. 2008). These approaches include membranes, cryogenic, absorption, and adsorption among other approaches. In this paper, adsorption process is used as the preferred approach in the gas separation process.