Primus Green Energy Inc., an alternative fuel company that converts natural gas and other feedstocks directly into drop-in transportation fuels and solvents (earlier post), announced that its patent application covering its STG+ liquid fuel synthesis technology has been allowed by the US Patent and Trademark Office (USPTO). STG+ produces high-quality, cost-effective, drop-in liquid transportation fuels directly from syngas derived from natural gas and other carbon-rich feedstocks in a single-loop process.
STG+ essentially improves upon commercial methanol synthesis processes and ExxonMobil’s methanol-to-gasoline (MTG) process, combining them into an integrated, optimized system that efficiently converts syngas directly to fuels. In addition to the gasoline product, the STG+ process can also produce jet fuel, diesel and high-value chemicals by changing the catalysts and operating conditions. The company, which is currently producing synthetic gasoline at its demonstration plant (earlier post), plans to build several more reactors in parallel to the current production train for other fuel products.
Primus says that STG+ represents a cost breakthrough for the GTL industry, as it demonstrates compelling economics at scales of less than 6,000 barrels per day. The patented process is simpler and more efficient than existing GTL technologies as it transforms syngas to liquid fuels with only one condensation step and also recycles untransformed gases.
These efficiencies result in a high-yield process—STG+ can convert one MMBtu of natural gas into more than five gallons of 90+-octane, drop-in gasoline. Another metric cited by the company is the ability of STG+ to convert 35% by mass of the syngas into final product.
STG+ is a new, proprietary thermochemical GTL process that fundamentally transforms the efficiency and economics of liquid fuel synthesis technologies. The allowance of this patent application validates the novelty of the technology we have developed and proven at scale in our research facilities and commercial demonstration plant here in Hillsborough. Further, it greatly strengthens our intellectual property portfolio, an important step as we look toward construction of our first commercial GTL plant.—Robert Johnsen, CEO of Primus Green Energy
In October 2013, Primus successfully commissioned its 100,000 gallon-per-year natural gas-to-gasoline demonstration plant. (Earlier post.) A recently concluded independent engineers report found that both catalyst performance and STG+ system economics exceeded expectations during demonstration plant operation. The company is now working toward construction of its first commercial plant, which is expected to produce 27.8 million gallons per year of drop-in gasoline from natural gas. The company expects to break ground on the plant in 2014.
Final issuance of the patent covering the STG+ technology is expected in March 2014.
Primus Green Energy is backed by IC Green Energy, Ltd., the renewable energy arm of publicly traded Israel Corp.
US Patent Application Nº 20120116137, Fang; Howard L. et al. Single Loop Multistage Fuel Production