Primus Green Energy produces 100-octane gasoline at commercial demonstration gas-to-liquids plant; improvement to STG+ technology
Primus Green Energy Inc., a gas-to-liquids (GTL) technology and solutions company that transforms methane and other hydrocarbon gases into gasoline and methanol (earlier post), has successfully produced 100-octane gasoline at its commercial demonstration plant in Hillsborough, New Jersey.
Primus achieved this milestone as a result of an improvement to its proprietary STG+ technology—itself essentially an improvement upon commercial methanol synthesis processes and ExxonMobil’s methanol-to-gasoline (MTG) process—which allows its plant to produce high-octane gasoline in addition to RBOB (“Reformulated Gasoline Blendstock for Oxygenate Blending”) gasoline and methanol.
RBOB is one of the base gasoline stocks mixed with ethanol at the terminal racks, the others being Conventional Gasoline Blending Components (CBOB) and CARBOB, a special RBOB formula mandated by the state of California. The end result of RBOB blending with ethanol is the gasoline fuel delivered to retail pumps—i.e., the three octane grades of 87 (R+M)/2, 89 (R+M)/2, and 93 (R+M)/2.
With the production of 100-octane zero-sulfur, zero-benzene, zero-lead gasoline, Primus could address fuels that meet European Union (EU) and Commonwealth of Independent States (CIS) specifications. There is also potential for this high octane gasoline to address the needs of the 100LL aviation gasoline (avgas) market, totaling 150-200 million gpa in the United States.
The Primus Gas-to-Gasoline STG+ process consists of three steps:
Steam Methane Reforming. Natural gas or other hydrocarbon gas reacts with steam at a high temperature and pressure to produce syngas (H2,CO and CO2 ).
Syngas-to-Gasoline. A series of catalytic fixed-bed reactors convert the syngas into gasoline and water via methanol and dimethyl ether intermediates.
Liquid/Gas Separation. The products are cooled and condensed. The gasoline product is sent to storage; the water is reused to make steam for the reformer; and the unconverted gas is recycled, with a portion being used to fuel the reformer.
Primus’ STG+ technology can use a range of natural gas feedstocks, including wellhead and pipeline gas, dry or wet associated gas, “stranded” ethane, excess syngas from underutilized reformers or mixed natural gas liquids. The systems’ stranded and associated gas applications offer a solution to the lack of traditional natural gas pipeline infrastructure in remote locations, enabling the monetization of gas that would otherwise be stranded or flared. The low-cost, modular systems can be trucked in and assembled onsite for easy deployment.
The STG+ process has been validated through more than 7,500 hours of operation at Primus’ commercial testing plant. By comparison with other GTL technologies, the process holds many key advantages, including record low capital and operating costs, high liquid product quality, zero wastewater, unmatched process simplicity and one of the best conversion yields on the market, the company says.
These advantages result in STG+ technology being economical at all scales, starting as small as 100,000 Nm3 (5 million scf) per day of feed gas.