石灰石直接硫化实验研究

Experimental Study on Direct Sulfation Reaction of Limestone with SO_2

进行了在高CO2浓度下石灰石直接硫化实验研究。实验研究了温度、CO2分压、O2分压及SO2浓度对石灰石直接硫化的影响。结果表明,温度对直接硫化反应速率影响很大,随温度的升高直接硫化速率增大,在所试验的时间内,当温度为1173K时,Ca转化率可以达到87%,当转化率≈0时,测得表观活化能为93.5kJ/mol,且表观活化能随Ca转化率的升高而增加;与温度相比,CO2分压对石灰石直接硫化几乎没有影响,增加CO2分压只是延缓石灰石的分解,提高石灰石的分解温度;在5%以下随O2分压的增加,直接硫化速率随之增加,O2分压超过5%以后,O2分压对石灰石直接硫化就没有什么影响;随SO2浓度的增加,直接硫化速率升高。

The direct sulfation reaction of limestone with SO_2 was investigated with thermogravimetry under the condition that the CaCO_3 does not decompose to CaO by controlling CO_2 partial pressure in this paper. The effects of several parameters in terms of temperature, CO_2 partial pressure, O_2 partial pressure, and SO_2 partial pressure on the reaction rate of limestone were verified in the study. The temperature has a strong influence on the reaction rate of limestone with SO_2 for the CaCO_3. THe direct sulfation rate rises with the temperature increasing. The Ca conversion can reach 87 % when the temperature is 1 173 K. The rate data at low conversions (ca.0) were used to estimate the apparent activation energy for the direct sulfation reaction when controlled by chemical kinetics. An apparent activation energy value of 93.5 kJ/mol was obtained. And the apparent activation energy increases with conversion rate increasing. In contrast, the CO_2 partial pressure has no effect on the direct sulfation rate until limestone decomposition is attained. The O_2 partial pressure has no effect on the direct sulfation rate when the O_2 partial pressure is above 5 %. The direct sulfation rate rises with increase in the SO_2 concentration at the same time.