Development of nickel based catalyst for the production of renewable hydrogen by autothermal reforming of crude glycerol

目前，氢气(H2)主要由化石燃料生产，化石燃料不仅是不可再生资源，而且还会造成温室气体排放。或者，将生物燃料(如乙醇和甘油)转化为氢气有可能提供长期的能源供应解决方案。在这些燃料中，甘油特别令人感兴趣，因为它的储量丰富，能量密度高，易于运输，而且有可能从环境负担转变为最终价值产品。生物柴油生产中产生的粗甘油含有盐、水、酒精和游离脂肪酸等杂质。在重整过程中，其中一些杂质的存在会导致严重的结焦和性能衰退。甘油气相重整制氢的方法有水蒸气重整、部分氧化和自热重整(ATR)。甘油的水蒸气重整反应在文献中得到了广泛的研究。然而，催化剂失活、结焦和氢产率下降仍然是一个主要挑战。贵金属催化剂表现出很高的抗焦性，但价格昂贵。镍基催化剂价格较低，但也表现出与贵金属基催化剂相当的活性。因此，开发稳定的粗甘油重整镍基催化剂受到了极大的关注。此外，据报道，添加氧气和使用高蒸汽与碳的比率可以最大限度地减少焦炭的形成。此外，甘油的水蒸气重整是吸热的，而甘油的ATR是放热的(即不需要外部能量输入)。然而，甘油在活性镍基催化剂上的ATR反应在文献中尚未见报道。本研究的总体目标是开发一种镍基高性能稳定催化剂，用于粗甘油ATR高效生产氢气。这将把甘油从一种低价值的副产品转化为一种有价值的制氢生物原料。此外，开发的催化剂将使甘油在较低的温度下转化，这意味着可以使用更便宜的材料进行建筑，从而导致更低的资本成本。总体而言，本研究将通过解决甘油过剩问题，使生物柴油的广泛生产成为可能，并提高生物柴油生产的经济性。

At present, hydrogen (H2) is produced largely from fossil fuels which are not only non-renewable resources but also contribute to greenhouse gas emissions. Alternatively, the conversion of bio-based fuels (e.g. ethanol and glycerol) to H2 has the potential to provide a long term energy supply solution. Among these fuels, glycerol is of particular interest due to its abundance, high energy density, ease to transport, and the possibility to change from an environmental burden to end value product. Crude glycerol from biodiesel production contains impurities such salts, water, alcohol, and free fatty acids. The presence of some of these impurities can cause severe coking and performance decay during the reforming process. The options for gas phase reforming of glycerol to H2 are steam, partial oxidation, and autothermal reforming (ATR). The steam reforming of glycerol has been widely investigated in the literature. However, catalyst deactivation, coking and reduced H2 yield remain a major challenge. Noble metal-based catalysts demonstrate high resistance to coking but are expensive. Ni-based catalysts are cheaper but also exhibit comparable activity with noble metal-based catalysts. Hence, the great interest in the development of a stable Ni-based catalysts for the crude glycerol reforming. Also, it has been reported that adding oxygen and the use of high steam to carbon ratio would minimize char formation. Further, steam reforming of glycerol is endothermic whereas ATR of glycerol is exothermic (i.e. require no external energy input). However, ATR of glycerol over active Ni-based catalysts has not been reported before in the literature. The overall objective of this research is to develop a Ni-based high performance stable catalyst for the efficient production of H2 by the ATR of crude glycerol. This will covert glycerol from a low value byproduct to a valuable H2 production bio-feedstock. Also, the developed catalysts will enable glycerol conversion at lower temperatures implying that cheaper material can be used for construction thereby resulting in much lower capital costs. Overall, this research will enable the widespread production of biodiesel by solving the glycerol glut problem, and improve the economics of biodiesel production.