ENHANCING CARBON (IV) OXIDE ADSORPTION FROM FLUE GAS MIXTURE AT ELEVATED TEMPERATURE USING COMPOSITE OF NANOPARTICLES

Abstract: Chitosan/clay materials from periwinkle shells and clay soil at a 50:50 ratio was made adsorbent and characterized, used for the adsorption of CO2 from flue gas at elevated temperatures (50 oC – 500 oC) in a fixed bed column (length 1.5m, and internal diameter 0.02m). Flue gas with composition of Methane (0.003), Ethane (0.002), Hydrogen (0.05), CO2 (0.15), Water Vapour (0.02), and Nitrogen (0.76), of pressure 49KPa, temperature of 500 oC, and flow rate of 75min/L from the exhaust tank; enters the fixed bed column for the adsorption process where the adsorbent is already placed. The results of the characterization of the adsorbent showed that 5.283nm, 2.64nm, 434.7m2/g, 704.2m2/g, 0.202cc/g, and 56.73% were best the values for the adsorbent’ pore width, pore diameter, microspore surface area, pore volume, and porosity, obtained using Dubinin-Raduskevich (DR), density functional theory (DFT), hydraulic diameter (DH), Langmuir, DH, and scanning electron microscope (SEM) analysing techniques respectively. The Fourier transform infrared (FTIR) Spectrum showed the presence of halogen (C-Cl), 20 alcohol (C-O), Nitro (N-O), and amine (N-H) compounds in the nanoparticles, revealing a strong affinity for CO2 particles in the flue gas. Another analysis showed the presence of elements (Ca, Si, Al, and Sr) in high compositions (0.470, 0.202, 0.186, and 0.092, respectively), revealing that the adsorbent is resistant to high temperatures. X-ray diffraction (XRD) analysis of the adsorbent gave Ca (OH)2, CaCO3, and TiO2 with compositions of 0.78, 0.19, and 0.026, respectively which revealed the strong affinity of the adsorbent for CO2. The Surface morphology of the adsorbent revealed that the surface was very rough and contains variety of pores or holes with wide capacities, indicating that more CO2 was captured and accommodated within the surface. Thermal analysis using the Barrett-Joyner-Halenda (BJH) method revealed that the adsorbent could withstand high temperatures up to 9000C, at this temperature, the adsorbent is only about 18% of the amount that enters the fixed-bed column for adsorption, but 100% of it can remain in the process for temperatures ranging from 0 oC – 300 oC. Finally, it was revealed that 95% of CO2 was adsorbed at the maximum value for the temperature (50 oC – 350 oC), time (0.5 - 5hr), and bed height (1 - 6cm).