Characterization of catalyst pellets involves various techniques to understand their physical and chemical properties: - Surface Area Analysis: Techniques like BET (Brunauer-Emmett-Teller) analysis are used to measure surface area. - Porosity and Pore Size Distribution: Mercury intrusion porosimetry and nitrogen adsorption-desorption isotherms are common methods. - Mechanical Strength: Crush strength tests ensure that pellets can withstand operational pressures.