基于氧化镁载体的硫酸铵释氨反应动力学研究

Reaction kinetics of ammonia gas release from ammonium sulfate with magnesium oxide carriers

硫酸铵((NH4)2SO4)是生产己内酰胺、烟气脱硫等工业过程的副产品,以金属氧化物为载体、采用化学链循环方法可将硫酸铵分解,得到附加值较高的氨气和硫酸。为了选择合适的载体,得到相应的反应动力学方程,首先采用热重法筛选出了最佳载体氧化镁(MgO),然后采用固定床热解实验系统考察了温度、反应物粒径、反应物摩尔比等对热解释氨反应的影响。结果表明,(NH4)2SO4与载体MgO混合热解释氨过程的表观反应动力学分为两个阶段,低温段属于界面反应控制的液-固反应,表观活化能为96.950 kJ·mol^-1;高温段属于界面反应控制的固-固反应或固体分解过程,表观活化能为113.656 kJ·mol^-1,反应物和载体的粒径对反应速率影响不大。

Ammonium sulfate is a by-product from industries such as caprolactam production and flue gas desulfurization,which can be decomposed to obtain high value-added ammonia and sulfuric acid by chemical chain technology with mental oxide as carriers.In order to optimize carriers and obtain corresponding reaction kinetics,magnesium oxide(MgO)was selected by thermogravimetric analysis.Fixed bed experiments were then carried out to systematically investigate the effects of temperature,reactant particle size and reactant molar ratio on reaction rates.The results show that the apparent kinetics can be divided into two stages for the decomposition process of(NH4)2SO4 with MgO to release ammonia gas.The low-temperature stage corresponds with phase boundary controlled liquid-solid reaction,and the apparent activation energy is 96.950 kJ·mol^-1.The high-temperature stage corresponds with phase boundary controlled solid-solid reaction or solid decomposition process,and the apparent activation energy is 113.656 kJ·mol^-1.The particle size of(NH4)2SO4 and MgO has little effect on reaction rate.