纳米添加剂对燃烧固硫影响特性研究

Effect of nano-additive on desulfurization during combustion

采用自制的纳米TiO2作为燃烧固硫添加剂,对纳米TiO2催化CaCO3的分解过程进行了热重试验研究,对固硫后气体吸收液和固体产物分别进行了离子色谱和红外光谱分析,并采用Coats and Redfern模型对CaCO3分解反应的动力学过程进行了计算。结果表明,纳米TiO2对CaCO3的分解有明显的促进作用,可使分解温度降低、反应活化能E下降;纳米TiO2会导致CaCO3晶格扭曲,减小微晶的晶格能,促进CaCO3分解成反应活性高的CaO分子;纳米TiO2会加快O2的吸附速度,使添加剂周围煤的反应速度加快,同时促进SO2转化成SO3,以及SO2向CaO的内部扩散,完全燃烧产物还会抑制CaSO3的分解,从而提高CaCO3的固硫效果。

By using the self-prepared nano-TiO2as sulfur retention additive during combustion,thermogravimetric experiment on nano-TiO2catalyzing the CaCO3decomposition was performed.Moreover,the gas absorption liquid and solid products after desulfurization were analyzed by ion chromatography and infrared spectrum method,respectively.Furthermore,the Coats and Redfem model was employed to conduct calculation for the kinetic process of CaCO3decomposition.The results showed that,the nano-TiO2enhanced the CaCO3decomposition obviously,namely the reaction activation energy Edecreased with the reaction temperature;in the presence of nano-TiO2,the CaCO3crystal lattice was distorted and the crystal lattice energy decreased,improving the CaCO3decomposing to CaO with high reactivity;on the other hand,the nano-TiO2can accelerate the absorption rate of O2to speed up the reaction rate of coal particles around the additive,improve the SO2converting to SO3and promote the SO2dispersing into the inner CaO,at the same time,the complete combustion products can inhibit the CaSO3decomposition so as to improve the desulfurization effect.