Influence of desorption parameters on regeneration process and regeneration effect of activated coke

The thermal desorption parameters of activated coke are crucial to the desulfurization and denitrification performance and mechanical strength of regenerated activated coke. In order to clarify the influence of desorption parameters on the regeneration process and regeneration effect of activated coke, the effects of desorption temperature and desorption time on the residual ratio of desulfurization product in activated coke, the amount of CO₂ and CO generated, and the desulfurization and denitrification performance of regenerated activated coke were investigated through thermal desorption experiments to determine the appropriate thermal desorption parameters of activated coke. The results show that the desulfurization products are rapidly decomposed at around 317 ℃ in the process of activated coke thermal desorption, and then the decomposition rate drops rapidly. After entering the constant temperature desorption stage, the decomposition rate of desulfurization products first decreases rapidly and then enters a slow desorption state, and the residual sulfur ratio decreases with the increase of constant temperature desorption temperature. The residual sulfur ratio decreases with the increase of constant temperature desorption temperature, and desulfurization products can be completely resolved at 530 ℃ for 3 h. When the desorption temperature is higher than 430 ℃, the decomposition amount of oxygen-containing functional groups, such as phenolic, quinone, lactone, on the surface of activated coke increases significantly, and continues to increase with the increase of constant desorption temperature. And the amount of CO₂ and CO generation will also increase significantly, which will further develop the pore structure of the activated coke, which is not conducive to the maintenance of mechanical strength of the activated coke. When the desorption temperature is lower than 530 ℃, the residual sulfur ratio continues to decrease with the increase of desorption temperature, so that the desulfurization and denitrification performance of the regenerated activated coke continues to be improved. After the desorption temperature is higher than 530 ℃, the decomposition amount of oxygen-containing functional groups continues to increase with the increase of desorption temperature, which will help to improve the SO₂ oxidation reaction rate on the surface of activated coke, and then the desulfurization performance of regenerated activated coke will continue to increase. The decomposition of acidic oxygen-containing functional groups such as phenolic and lactone groups reduces the adsorption performance of regenerated activated coke for NH₃, thereby reducing its denitration performance. When considering various factors such as desulfurization and denitrification performance, mechanical strength and production efficiency of regenerated activated coke, constant temperature analysis at 430 ℃ for 3 h is a relatively optimal desorption parameter. Under these conditions, the residual sulfur ratio is only 1.8%, the oxygen-containing functional groups have not been decomposed in large quantities, and the desulfurization and denitrification performance of regenerated activated coke is relatively good.