(584f) Partial Oxidation of Ethanol Over Supported Ni Catalysts: Effect of Support

Hydrogen is forecasted to become a major energy carrier for the future since it can reduce pollution and greenhouse gas emissions. Therefore, the large amounts of hydrogen will be required in a hydrogen economy.

Hydrogen can be produced from hydrocarbons (HCs) such as natural gas, naphtha, vacuum residue, refinery off-gas, gasoline, diesel, methanol etc. Among these, ethanol is a very promising candidate because it is a renewable raw material that can be obtained from biomass and addresses the CO₂ emission. Furthermore, the infrastructure needed for ethanol production and distribution has already been established in Thailand for producing gasohol.

There are three main methods for producing hydrogen from HCs, namely steam reforming (SR), partial oxidation (POX), and autothermal reforming (ATR). POX of ethanol is an attractive process for hydrogen production because it enables fast start up and does not need the addition of heat. However, this process has some disadvantages such as formation of by-products and catalyst deactivation. Hence, the catalysts which are highly active, selective and stable under reaction conditions are needed. Nickel-based catalysts are attractive for POX of HCs due to their low cost. Since support plays a significant role on performance of supported metallic catalysts on this reaction, the study concerning the effects of metal and support on POX of ethanol is needed.

In this study, the effect of the support on the catalytic activity of Ni/Al₂O₃, Ni/Ce_0.75Zr_0.25O₂, Ni/ZrO₂ and Ni/MgO catalysts for the POX of ethanol was investigated in a fixed bed reactor over the temperature range of 300-700^oC. The results showed that the product distribution depended on the type of support. The main products of the reaction were H₂ and CO₂ for all catalysts. Ni/Ce_0.75Zr_0.25O₂ catalyst presents the higher activity and selectivity towards H₂ than the other catalysts. Moreover, the Ni/Ce_0.75Zr_0.25O₂ catalyst can be operated in a wider C/O feed ratio range due to its good redox properties. More details about the effect of the support on the performance of these Ni-based catalysts on the POX of ethanol will be discussed in the paper.