改性BaFe_(2)O_(4)载氧体生物质化学链气化特性

Biomass chemical-looping gasification characteristics of K-modified BaFe_(2)O_(4) oxygen carrier

以溶胶凝胶法制备了BaFe_(2)O_(4)载氧体以及Ni、Ce、K修饰的BaFe_(2)O_(4)载氧体,筛选出最佳载氧体为10%(质量)K修饰的BaFe_(2)O_(4)载氧体(10K-BF),探究了不同反应条件对其性能的影响,通过H_(2)-TPR、XRD、SEM、BET对载氧体表征。实验结果表明,Ni、Ce、K的添加均提高了载氧体的合成气产率,10K-BF载氧体在水蒸气与生物质质量比(S/B)等于3,过氧系数α=0.20,反应温度800℃时,气化效果最好,合成气产率1.864 m^(3)/(kg Biomass),氢气产率1.038 m^(3)/(kg Biomass),碳转化率90.49%,积炭率1.33%,10次循环后仍有较高的气体产率及碳转化率。H_(2)-TPR表明10K-BF载氧体在300℃开始释氧,在生物质热解的初始阶段即可参与反应,有利于焦油的裂解;XRD表明10K-BF载氧体再生后可以恢复部分尖晶石结构。

The BaFe_(2)O_(4) oxygen carrier and BaFe_(2)O_(4) oxygen carrier modified by Ni,Ce and K were prepared by the sol-gel method,and the best oxygen carrier was selected as 10%(mass)K modified BaFe_(2)O_(4)(10K-BF),and the difference was explored.The effect of reaction conditions on its performance was characterized by H_(2)-TPR,XRD,SEM,and BET on the oxygen carrier.The experimental results showed that the addition of Ni,Ce and K all increase the syngas yield.The 10K-BF oxygen carrier exhibited the best performance when the mass ratio of steam to biomass(S/B)was equal to 3,peroxygen coefficientα=0.20 and t=800℃.Its syngas yield was 1.864 m^(3)/(kg Biomass),hydrogen production rate was 1.038 m^(3)/(kg Biomass),carbon conversion rate was 90.49%and carbon deposition rate was 1.33%.After 10 cycles,there was still a high syngas yield and carbon conversion rate.H_(2)-TPR result indicated that the 10K-BF oxygen carrier starts to release oxygen at 300°C and can participate in the reaction at the initial stage of biomass pyrolysis,which is beneficial to the cracking of tar.XRD characterization showed that the 10K-BF oxygen carrier can recover part of the spinel structure after regeneration.