摘要
根据化学链燃烧原理,进行了以CaSO4为载氧体,以CO为燃料的化学链燃烧还原反应动力学试验研究,并基于标准Gibbs自由能最小化原理,研究了以煤为燃料,CaSO4为载氧体化学链燃烧周期性的还原-氧化反应过程.结果表明:CO还原CaSO4的气相产物主要为CO2,固相产物主要为CaS而不是CaO;通过CO浓度为20％～70％,温度为880～950℃条件下的还原反应验证了还原反应动力学模型,求出相关的动力学参数;试验得到的结果和拟合结果非常吻合.
The low cost CaSO4based oxygen carrier has been proposed as an alternative oxygen carrier for chemical-looping combustion of coal.The reduction of CaSO4to CaS is an important step for the cyclic process of reduction/oxidation in chemical-looping combustion of coal with CaSO4based oxygen carrier.Thermodynamic analysis of CaSO4oxygen carrier with CO based on the principle of the Gibbs free energy minimization showed that the main products of reduction were CO2,while the solid products were CaS instead of CaO.The reduction kinetics of a CaSO4based oxygen carrier with CO was investigated in a differential fixed bed reactor.The effects of gas partial pressure(20%-70%)and temperature(880-950℃)on the reduction were investigated.The reduction was described with shrinking unreacted core model.Experimental results of CO partial pressure on the solid conversion showed that the chemical reactions were of first order with respect to the CO and H2partial pressure for the fresh oxygen carriers.Both chemical reaction control and product layer diffusion control determined the reduction rate.The dependences of reaction rate constant and effective diffusivity with temperature were both obtained.The kinetic equation well predicted the experimental data.The kinetic study provided important information for the future use of CaSO4oxygen carrier in CLC of solid fuels and the design criteria of a CLC system.
出处
《热力发电》
CAS
北大核心
2013年第11期37-42,共6页
Thermal Power Generation
