Catalysis of thermo-catalytic methane decomposition : a thesis presented for the degree of Master of Science in Nanoscience at Massey University, Palmerston North, New Zealand

Abstract

The use of hydrogen gas as an energy carrier is a proposed pathway to eliminating greenhouse gas emissions from fossil fuels. However, emissions-free production of hydrogen is more costly than traditional high-emissions hydrogen production processes such as Steam Methane Reformation (SMR). To address this, a process called Thermo-catalytic Methane Decomposition (TCMD) is being commercially developed. This process uses methane (natural gas) to produce hydrogen gas and high quality solid carbon which can be sold to offset the price of the hydrogen produced. TCMD has the potential to be cost-competitive with SMR. A key feedstock in the TCMD process is a low cost catalyst, because the carbon produced deposits on the catalyst and deactivates it. The most commercially viable choice of catalyst has been identified as iron ore, or hematite, due to its high activity and lifetime, and its low cost [13, 23]. The TCMD process could have applications in New Zealand to supply the heavy transport market, but for this to happen, a domestic source of iron ore is required for use as a catalyst. New Zealand’s primary source of iron ore is in the form of titanomagnetite found in ironsands, which has different properties to hematite. As a result, this research was commissioned to evaluate the effectiveness of New Zealand ironsands as a catalyst for TCMD. The effects of temperature, flow rate, catalyst composition, and aggregate particle size on ironsand catalytic activity, lifetime, and carbon by-product quality are evaluated relative to a hematite control.