Adsorb-Catalytic Removal of PH3 and H2S in Yellow Phosphorus Off-Gas by Metallic Modified Activated Carbon

Abstract

Activated carbon modified with Cu²⁺ and Co²⁺ was used to remove PH₃ and H₂S from yellow phosphorus off-gas. An orthogonal experiment was carried out to identify the superiority order of influencing factors and the optimal experimental parameters. For PH₃, the superiority order was temperature > oxygen content > parch temperature > impregnant concentration (Cu²⁺) > flow rate > diameter, whereas, for H₂S, it was reaction temperature > oxygen content > impregnant concentration > parch temperature > diameter > flow rate. Following were the optimal experimental parameters for both PH₃ and H₂S: reaction temperature, 95°C; impregnant concentration (Cu²⁺), 0.25 mol/L; diameter of metallic modified activated carbon (MMAC), 3.5 mm; oxygen content, 1%; parch temperature, 300°C; and flow rate, 0.4 L/min. Regeneration of MMAC was effective for PH₃ but not compelling for H₂S. The activation energy and reaction orders were calculated, and the transmission process was evaluated to assess the characteristics of the dynamics of the adsorb-catalytic reaction. The reaction orders were -0.8 and -0.76 for PH₃ and H₂S and the average activation energies were 1247.6 and 134.4 J/mol for PH₃ and H₂S, respectively. The adsorb-catalytic reaction was fast, and decreasing transmission resistance can play a key role in improving the performance of MMAC.