石灰石与SO_2直接硫酸化反应宏观动力学的研究

KINETICS OF THE DIRECT SULFATION REACTION OF LIMESTONE WITH SO_2

温度、ＳＯ＿２浓度、颗粒大小、石灰石类型和样品的微观结构影响着直接硫酸化反应过程。这一反应过程能用缩芯模型来描述，并对ＳＯ＿２具有一级反应特征。本征反应和产物层扩散控制反应的活化能分别是８５．２ｋＪ／ｍｏｌ和４１．５ｋＪ／ｍｏｌ。在８００℃、２０００ｐｐｍＳＯ＿２和反应１０１ｍｉｎ的条件下，Ｉｇｚｌａｂｅｒｇａ和Ｆｏｒｓｂｙ石灰石的ＣａＣＯ＿３转化率分别可达８４％和７２％。在初始２ｍｉｎ内已煅烧石灰石（ＣａＯ）的硫酸化反应速率与石灰石的反应速率稍高，随后二者基本相同。

Temperature, SO_2 concentration,particle size,limestone type and ori-ginal micro structure of sample affect the overall process of direct sulfation. This process can be described by using a shrinking core model .The reaction is found of first order with respect toSO_2.The values of activation energy are 85.2kJ/mol for the intrinsic reaction and 41.5kJ/mol for the reaction controled by the product-lay-er diffusion.At800℃,2000ppm SO_2 and 10 min,the CaCO3 conversion as high as84%and 72%can be expected for Ignaberga and Forsby,respectively,It seems that the sulfation of precalcinedl imestone(CaO)has little faster rate than the direct sulfa-tion of limestone during the first 2 min, and then both have almost same rate.