Development of a novel low temperature single step technology for direct liquefaction of methane-rich gas streams to oxygenated hydrocarbon fuels

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One of the areas that are currently under scrutiny as the world battles energy challenges for the future is considerable energy generation from methane (CH4)-rich gas streams such as natural gas (NG), sub-quality NG, stranded NG, and biogas. However, the major challenge to the use of a CH4-rich gas is the difficulties in transportation due to its low energy density by volume (0.036 MJ/l), thus it is transported as compressed gas under high pressure which is energy intensive and uneconomical. This explains why for example more than 150 billion cubic meters of natural gas (associated with oil production and low quality) is flared and/or vented worldwide every year. A more realistic and economical option would be to convert the CH4-rich gas to a useful liquid fuel such as methanol or other value added chemicals like formaldehyde at the source prior to transporting. Presently, methanol is being produced from methane in a two-step process where methane is first converted into synthesis gas via steam reforming, followed by high-pressure catalytic conversion of the syngas into methanol. The process is not only uneconomical due to energy and time consumption, but it also has inherent risks due to the extremely harsh process conditions of temperature and pressure. Hence, the direct CH4-rich gas conversion to methanol is indeed a dream process to be explored since it involves a single step reaction. This process if carefully researched and optimized would significantly reduce the cost of methanol and other oxygenates production from CH4-rich gases thus making the process more attractive towards meeting the global demands. Hence, it is an overall objective of the current phase of the research program to develop a low cost and efficient photocatalytic process for the direct conversion of CH4-rich gas streams to oxygenated fuels at low temperature and to gain insight into the process chemistry. The novelty aspect of this research is the game changer from the traditional route of CH4-rich stream conversion to methanol via syngas production in expensive high temperature successive steps to a lower cost single step low temperature direct liquefaction process. Also, this is the first time that the concept of combining photocatalysis and modified photo-assisted Fenton-like process to generate an environment enriched in highly reactive hydroxyl radical will be developed and implemented for low temperature direct CH4-rich gas streams liquefaction to oxygenated fuels in a single step. Methanol produced through the proposed process can be used in fuel cells; blended with gasoline; converted to gasoline or dimethyl ether, which is a component of diesel fuel; and converted to ethylene and propylene, which are precursors to a wide range of chemicals. The benefits to Canada include the development of exportable advanced technology, international recognition and global leadership in this emerging energy production capability.