Hydrogen production from bio-methane and bio-ethanol in catalytic membrane reactors

我们小组最近开发的两种膜将对其氧和氢的传输行为进行微调，并用于催化膜反应器，将(a)生物甲烷和(b)生物乙醇转化为氢：氧传输钙钛矿型和双相膜和氢传输纳米孔膜。该项目包括优化氧和氢通过相应膜的传输，实施合适的催化剂，建立氧/氢传输与催化反应速率之间的动力学相容性，最后测试与实践相关的生物甲烷和生物乙醇原料。我们在《安吉旺特化学》（Angewandte Chemie）上发表的一篇中德联合论文中，提出了将热水裂解与甲烷部分氧化（POM）结合成合成气的概念。然而，该原理证明中的产氢率相对较低，因为(i)没有使用催化剂进行水裂解制氢，（ii）由于轴向反应器尺寸的变化，气体浓度（即渗透和催化的驱动力）发生了变化，因此使用的中空纤维膜反应器不适合进行定量研究。(3)镍基蒸汽重整催化剂不允许甲烷的快速一步催化部分氧化生成合成气。因此，我们将在考虑动力学相容性的情况下，在平面盘状膜反应器中使用新型催化剂，在新的几何排列中允许氧气溢出，从而研究将水裂解和POM结合在一起的制氢方法。通过集成氢选择膜提高乙醇蒸汽重整产氢率的概念在最近的研究中得到了积极的证实。然而，这些研究表明，在蒸汽重整条件下，即在蒸汽、CO和CO2存在下，Pd（或Pd合金）和硅基分子筛膜都不稳定。我们最近开发的疏水氢选择金属有机框架分子筛膜为以催化膜反应器的形式加强乙醇的蒸汽重整反应提供了重要的机会。

Two kinds of membranes that were recently developed in our groups will be fine-tuned in their oxygen and hydrogen transport behaviour and used in catalytic membrane reactors for the transformation of (a) bio-methane and (b) bio-ethanol into hydrogen: oxygen-transporting perovskite-type and dual phase membranes and hydrogen-transporting nanoporous membranes. The project covers optimization of oxygen and hydrogen transport through the corresponding membranes, implementation of suitable catalysts, establishing kinetic compatibility between oxygen/hydrogen transport and the rate of the catalytic reactions and finally the testing of practice-relevant feeds of bio-methane and bio-ethanol.The concept of combining thermal water splitting with the partial oxidation of methane (POM) to synthesis gas, has been shown by us in a joint Chinese-German publication in Angewandte Chemie. However, the hydrogen production rate in this proof of principle was relative low since (i) no catalyst has been used for hydrogen production by water splitting, (ii) a hollow-fiber membrane reactor has been used which is not suitable for quantitative studies since the gas concentrations (and thus the driving force for permeation and catalysis) change in axial reactor dimension, and (iii) the Ni-based steam reforming catalyst did not allow the kinetically fast one-step catalytic partial oxidation of methane to synthesis gas. Therefore, we will study hydrogen production by combining water splitting and POM in a planar disc-shaped membrane reactor under consideration of kinetic compatibility by using novel catalyst in a new geometric arrangement which allows oxygen spill over.The concept of improving the hydrogen yield in steam reforming of ethanol via integrating hydrogen selective membranes has been positively proofed in recently studies. Nevertheless, these studies show that neither Pd (or Pd alloy) nor silica-derived molecular sieve membranes were stable in the steam reforming conditions, i.e. in the presence of steam, CO, and CO2. Our recently developed hydrophobic hydrogen-selective metal-organic framework (MOF) molecular sieve membranes provide an important opportunity to intensify the steam reforming reaction of ethanol in the form of a catalytic membrane reactor.