(653f) Production of Fuels From Natural Gas Through a Hybrid Thermochemical/Biochemical Gas Fermentation Process

Natural gas is currently an abundant, low-cost feedstock in the United States that can be used to produce fuels and chemicals through a variety of thermochemical conversion routes. Over recent decades, there has been an ever-increasing focus on developing alternative technologies to produce fuels through biological pathways either by using biomass as a feedstock or utilizing a biological process. LanzaTech has developed a hybrid thermochemical/biochemical gas fermentation process which produces fuels or fuel intermediates from natural gas.

Gas fermentation is a biological process in which microbes convert climate-active gases, such as methane, carbon monoxide, or carbon dioxide, into low-carbon fuels and chemicals. LanzaTech currently operates a gas fermentation process that utilizes biological renewable resources to convert carbon monoxide to ethanol and other fuel derivatives. The carbon monoxide can come from a variety of sources including industrial waste gases, such as steel mill off-gas, or any CO-containing syngas. Natural gas can be readily reformed to syngas through a variety of conventional thermochemical technologies, which can be converted to fuel through gas fermentation. The gas fermentation process has a number of distinct advantages over conventional thermochemical gas-to-liquid (GTL) routes, including syngas composition flexibility, reduced economic operating scale, and reduced gas clean-up requirements, providing cost and emissions benefits.

The integrated thermochemical/biochemical LanzaTech gas fermentation process for the production of fuels from natural gas is described including process economics and life cycle analyses; there is also active research on the direct fermentation of natural gas to fuels which will also be described. There are many natural gas assets that are currently uneconomical to exploit due to relatively low available volumes and/or high costs of gas transportation, CO₂ removal, or gas clean-up. Gas fermentation presents an enabling technology for small-scale deployment and accessing sources that are currently uneconomical to process and may be ultimately flared, vented, or emitted.