吸附强化焦油蒸汽重整制取氢气

Hydrogen production via sorption-enhanced steam reforming of tar

分别采用固相反应法、溶胶凝胶法制备了Ni/Mg-Ca_(12)Al_(14)O_(33)催化剂、CaO-Ca_(12)Al_(14)O_(33)吸附剂,并将其作为重整催化剂、CO_2吸附剂应用在焦油蒸汽重整制取氢气的研究中,通过与普通蒸汽重整进行对比,系统地研究了重整温度、S/C比(反应体系中水蒸气与碳元素的摩尔比)、质量空速对焦油吸附强化蒸汽重整制氢特性的影响。结果表明,CO_2吸附剂的加入能够有效提升焦油重整效果,氢气产率、体积分数均得到显著提高,其中氢气体积分数达95%以上。随着S/C比的增加、质量空速的减小,普通蒸汽重整和吸附强化重整的制氢效果均是增强的,且均在S/C比、质量空速分别达到12:1、0.128 h-1后增幅不再明显;尽管如此,相比普通重整,吸附强化重整降低了最佳重整制氢温度,在800℃时氢气产率能够达到87.35%。

The sorption-enhanced steam reforming process was applied to the tar removal to produce high-purity hydrogen.In this study,the reforming catalyst was Ni/Mg-Ca12Al14O33 prepared by solid-state reaction method,and the CO2 sorbent was CaO-Ca12Al14O33 prepared by sol-gel method.The effects of temperature,S/C ratio(the mole ratio of the steam to the carbon in the reaction system)and the WHSV(mass hourly space velocity)on enhancing hydrogen production from tar reforming.The results showed that the addition of the CO2 sorbent can improve the tar reforming efficiency,with the H2 yield and volume fraction increased significantly.Especially,the H2 volume fraction reached over 95%.As the S/C ratio rose and the WHSV declined,the hydrogen production was accelerated,for both of the common steam reforming and the sorption-enhanced reforming.And,for the two processes,when the S/C ratio reached over 12:1 and the WHSV reached below 0.128h^-1,the change of the reforming efficiency was no longer distinct.Compared to the common steam reforming,the best temperature to produce H2 was decreased for the sorption-enhanced reforming,and the H2 yield at 800℃ can reach 87.35%.Compared to thermodynamic results,the H2 yields from the experiment were lower,but the sorption-enhanced reforming can narrow the gap between the experimental and thermodynamic values.