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

在全球应对未来能源挑战的过程中，目前备受关注的领域之一是利用富含甲烷（CH4）的天然气（NG）、次优质NG、搁浅NG和沼气等天然气生产大量能源。然而，使用富ch4气体的主要挑战是运输困难，因为它的体积能量密度低（0.036 MJ/l），因此在高压下作为压缩气体运输，这是能源密集型和不经济的。这就解释了为什么全世界每年有超过1500亿立方米的天然气（与石油生产和低质量有关）被燃烧和/或排放。一个更现实和经济的选择是在运输前将富含ch4的气体转化为有用的液体燃料，如甲醇或其他增值化学品，如甲醛。目前，甲醇的生产采用两步法，首先通过蒸汽重整将甲烷转化为合成气，然后通过高压催化将合成气转化为甲醇。该工艺不仅由于能量和时间的消耗而不经济，而且由于温度和压力的极其苛刻的工艺条件而具有固有的风险。因此，直接将富含ch4的气体转化为甲醇确实是一个值得探索的梦想过程，因为它涉及到一个单步反应。如果仔细研究和优化这一过程，将大大降低从富含ch4的气体中生产甲醇和其他含氧化合物的成本，从而使该过程更有吸引力，以满足全球需求。因此，该研究项目当前阶段的总体目标是开发一种低成本、高效的光催化工艺，用于在低温下将富ch4气流直接转化为含氧燃料，并深入了解该工艺的化学性质。这项研究的新颖之处在于，它改变了传统的富ch4流通过昂贵的高温连续步骤合成气转化为甲醇的路线，转变为成本更低的单步低温直接液化过程。此外，这是第一次将光催化和改进的光辅助类芬顿工艺相结合的概念，以产生富含高活性羟基自由基的环境，并将其用于低温富ch4直接液化到含氧燃料的一步。通过该工艺生产的甲醇可用于燃料电池；与汽油混合的；转化为汽油或二甲醚，这是柴油燃料的一个组成部分；并转化为乙烯和丙烯，这是一系列化学物质的前体。对加拿大的好处包括发展可出口的先进技术，在这一新兴能源生产能力方面获得国际认可和全球领导地位。

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.