Syngas production on a Ni-enhanced Fe2O3/Al2O3 oxygen carrier via chemical looping partial oxidation with dry reforming of methane
Syngas production on a Ni-enhanced Fe2O3/Al2O3 oxygen carrier via chemical looping partial oxidation with dry reforming of methane
复制标题
DOI：
10.1016/j.apenergy.2017.11.018
复制
发表时间：
2018-02-01
期刊：
影响因子：
11.2
通讯作者：
Lee, Jae W.
中科院分区：
文献类型：
--
作者：
Kang, Dohyung;Lim, Hyun Suk;Lee, Jae W.
介绍了一种新型化学环法，将甲烷在经济高效的铁基氧载体上部分氧化和干重整相结合，制得H-2/CO比为2的高纯度合成气。热力学数据表明，引入CH4-CO2混合进料提高了合成气纯度，H-2/CO比接近2。与一般化学环化工艺相比，采用CO2与CH4共进料后，计算的碳沉积与CO2排放量显著降低。由于氧载体氧化反应的放热，新型化学环化工艺的净热负荷远低于干重整工艺。为了验证热力学结果，通过溶胶-凝胶途径增加金属-载体相互作用，合成了Ni包埋的Fe2O3/Al2O3氧载体。镍增强氧载体中镍铝酸盐相的形成促进了部分氧化的干重整，同时抑制了甲烷的分解。在900℃条件下，将非化学计量的CH4-CO2混合原料（CO2/CH4比0.38）添加到1 wt% ni包埋的Fe2O3/Al2O3氧载体中，H-2/CO比为2.09，CO选择性为96.76%，碳沉积最少。这些结果与计算的平衡值接近，而ni浸渍的Fe2O3/Al2O3氧载体的H-2/CO比增加了2.36，并且由于促进了甲烷的分解，导致了严重的碳沉积。此外，ni增强氧载体在连续的还原和氧化循环中也表现出稳定的氧化还原活性。
A novel chemical looping process was introduced by combining partial oxidation and dry reforming of methane on a cost-effective iron-based oxygen carrier to produce high-purity syngas with a H-2/CO ratio of 2. The rationale for the proposed chemical looping process was substantiated with the thermodynamic data, which showed increased syngas purity and an H-2/CO ratio close to 2 by introducing the CH4-CO2 mixture feed. Compared with the general chemical looping process, the calculated carbon deposition with the CO2 emission of the proposed process was dramatically decreased by using CO2 as a co-feed with CH4. Due to the exothermic heat from the oxidation reaction of the oxygen carrier, the net heat duty of the novel chemical looping process was much lower than that of the dry reforming process. To validate the thermodynamic results, a Ni entrapped Fe2O3/Al2O3 oxygen carrier was synthesized by increasing the metal-support interaction through a sol-gel route. It is striking that the formation of Ni aluminate phase in the Ni-reinforced oxygen carrier facilitated dry reforming with partial oxidation while suppressing methane decomposition. By supplying a nonstoichiometric, CH4-CO2 mixture feed (CO2/CH4 ratio = 0.38) to the 1 wt% Ni-entrapped Fe2O3/Al2O3 oxygen carrier at 900 degrees C, an H-2/CO ratio of 2.09 and high CO selectivity of 96.76% were achieved with minimized carbon deposition. These results were close to the calculated equilibrium value while a Ni-impregnated Fe2O3/Al2O3 oxygen carrier showed an increased H-2/CO ratio of 2.36 with severe carbon deposition by the promoted methane decomposition. In addition, the Ni-reinforced oxygen carrier also showed stable redox activity during successive reduction and oxidation cycles.