SO2 removal from flue gas by activated semi-cokes: 1. The preparation of catalysts and determination of operating conditions Original Research Article

The objective of this work was to use waste semi-coke as the raw material to prepare catalysts of industrial-scale size for SO2 removal from flue gas and to find the optimal preparation methods. Results showed that lignite semi-coke was a suitable raw material, and that the catalyst, prepared by pre-activating in an autoclave, oxidizing with HNO3, loading with CuSO4 and finally calcining at 700 °C, exhibited the best desulfurizing property with a sulfur retention of about 9.6% SO2/100 gC at a reaction temperature of 90 °C. Also, the effects of H2O content in the flue gas, reaction temperature and space velocity on the desulfurizing property were investigated to determine optimum operating conditions. An H2O content of 7% was appropriate for catalysts in this work. In the temperature range 80–120 °C, the catalyst showed good performance for SO2 removal and was gradually deactivated at temperatures above 120 °C. Space velocity exhibited an optimal value of 830 h−1. The kinetic behavior varied with space velocity and the desulfurizing property was controlled by diffusion at space velocities below 830 h−1, and controlled by adsorption or catalytic reaction at space velocities above 830 h−1.