解析参数对活性焦再生过程及再生效果的影响

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

活性焦的热解析参数对再生活性焦的脱硫脱硝性能和机械强度至关重要。为了明确解析参数对活性焦再生过程和再生效果的影响规律,通过热解析试验探究活性焦硫残余比例、CO_(2)和CO生成量及再生活性焦脱硫脱硝性能随解析温度和解析时间的变化规律,继而明确适宜的活性焦热解析参数。结果表明,活性焦升温解析过程中,脱硫产物在317℃左右迅速分解,随后分解速率下降;在进入恒温解析阶段后脱硫产物分解速率先快速下降,而后进入缓慢解析状态。硫残余比例随恒温解析温度的升高而下降,在530℃下解析3 h可使脱硫产物完全解析;解析温度高于430℃后,活性焦表面的酚基、醌基、内酯基等含氧官能团分解量明显增加,并随恒温解析温度的升高而持续增加,分解所生成的CO和CO_(2)也随之大幅增加,这将使活性焦的孔隙结构进一步发展,继而不利于活性焦机械强度的保持;解析温度低于530℃时,硫残余比例随解析温度的升高而持续降低,使再生活性焦的脱硫脱硝性能持续提高;解析温度高于530℃后,含氧官能团分解量随解析温度的升高而持续增加,这将有利于提高活性焦表面SO_(2)氧化反应速率,继而使再生活性焦的脱硫性能持续升高,但酚基、内酯基等酸性含氧官能团的分解使再生活性焦对NH;的吸附性能降低,进而使其脱硝性能降低。在兼顾再生活性焦脱硫脱硝性能、机械强度和生产效率等多方面因素时,430℃恒温解析3 h是相对较优的解析参数。在此解析条件下,再生活性焦的硫残余比例仅为1.8%,含氧官能团尚未发生大量分解,脱硫脱硝性能相对较为优良。

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 CO_(2)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 CO_(2)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 SO_(2)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 NH;,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.