生物炭-Fe_(2)O_(3)的制备及其脱除焦油模型化合物研究

Study on preparation of biochar-Fe_(2)O_(3) and its removal of tar model compound

为实现焦油的高效脱除,减少对设备、环境的危害,有必要寻找高效、低廉且无毒的催化剂材料。首先以低成本、孔道丰富的生物炭作为载体,采用水蒸气活化法和浸渍煅烧法制备了生物炭-Fe_(2)O_(3)焦油裂解催化剂;然后利用BET(Brunner-Emmett-Teller,全自动物理吸附仪)、XRD(X-ray diffraction,X射线衍射仪)、FTIR(Fourier transform infrared spectroscopy,傅里叶红外光谱仪)等对其物理化学性质进行表征;最后采用甲苯作为焦油模型化合物验证其催化效果。结果表明:提高活化温度和延长活化时间能显著提高生物炭比表面积,提高水蒸气体积分数也具有一定促进效果,但当水蒸气体积分数过高时效果有所减弱,而提高比表面积有助于提高甲苯脱除效率;在负载铁质量分数为4%时脱除效率最高达94.1%;在未负载铁时甲苯的脱除主要依靠生物炭多孔结构的物理吸附,在铁负载时产生了新的作用力,该作用力能弥补负载后比表面积减小导致吸附能力下降的缺陷。铁负载生物炭对焦油脱除具有良好的应用前景,本研究结果可为生物质气化脱除焦油提供一定的理论指导和技术创新参考。

In order to achieve efficient removal of tar and reduce the hazardous effects on equipments and the environment,it is necessary to find efficient,inexpensive and non-toxic catalyst materials.Firstly,the biochar-Fe_(2)O_(3)tar cracking catalyst was prepared bymeans of the steam activation method and the impregnation calcination method by using the low-cost biochar with abundant pores as the carrier;secondly,its physical and chemical properties were characterized by employing BET(Brunner-Emmett-Teller,automatic physical adsorption instrument),XRD(X-ray diffraction,X-ray diffractometer),FTIR(Fourier transform infrared spectroscopy),etc.;finally,toluene was utilized as a tar model compound to verify its catalytic effect.The results show that increasing the activation temperature and prolonging the activation time can significantly improve the specific surface area of biochar,and increasing the steamvolume fraction also has a certain promotion effect,but the effect is weakened when the steamvolume fraction is too high,and increasing the specific surface area is conducive to the toluene removal efficiency;the removal efficiency peaks at 94.1%when the mass fraction of Fe load is 4%;the removal of toluene when Fe being unloaded mainly relies on the physical adsorption of the porous structure of biochar,while a new force is generated when Fe being loaded,which can make up for the defect of diminishing adsorption capacity due to decrease of the specific surface area after loading.Fe-loaded biochar has a good application prospect for removal of tar,and the results of this study can provide theoretical guidance and technological innovation reference for biomass gasification tar removal.