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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:

  1. 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 ).

  2. Syngas-to-Gasoline. A series of catalytic fixed-bed reactors convert the syngas into gasoline and water via methanol and dimethyl ether intermediates.

  3. 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.



We have known this 40 years, now with cheap gas we can do it.


It may not be news to you, but this is a big deal for general aviation right now. Yes, creating an alternative to 100LL has been possible, but not at commercial scales needed for this modest market and certainly not at an economical price. Avgas is typically twice the price of regular gasoline, I have paid $6+ a US gallon before now and it is currently around $5.50 at KPAE while nearby gas stations are $2.20.

The industry has been needing an alternative to 100LL because of both the environmental issue, plus there is only one supplier in the world of the additive needed to boost it to 100 octane needed for the low-compression piston engines used by most prop planes.

The other issue is being a specialty product means it has to be trucked in from the refinery (and have special handling to prevent contamination). Being modular and small-scale, I wonder if it would be possible to produce this fuel on-site at major airports. I have no idea whether 5 million scf of feed gas is a lot, or something you could get from a regional gas main. Nor does it say how much gasoline that makes.

As Aha

100,000 Nm3 per day is ~40MW, so not small but not huge


The MTG process usually produces 87 octane but can be tuned to produce higher. This process has been known since the 1970s, they could have made aviation gasoline anytime.


For reference can anyone say why 100octane should be so desirable? Aside from the expectation that it will lose points over time, so better to start with a higher O rating?
Low compression aero engines may well cope with the low 87? Safety margin increase.
The other question R.E. LL additives.
How does this become irrelevant?
Through engine modifications during recertification or by phase out of older models?

There are now a plethora of fuels with A1 jet, diesel engines running A1 as well as conventional diesel when necessary?
LL avgas and this UL100.

Then there is the automotive options e10 -100. ulp 85,91,95 and 98. Presumably this UL 100 will end up tax aside almost legally in cars.
As is for the LL100's as well as now LL 110 legally for (classic) motor sport.

How does the industry plan to prevent mismatching fuels and engine type. Service fuel providers and mechanics becomes more specialised. They will more often have to know when to say "sorry can't do that."


My guess is that this will blend with ethanol to satisfy the feds but help step away from an apparently unwanted threshold of non-bioethanol production which (politically) can't meet the RFS. Stranded and co-gas covers a lot: Utica shale wells, coal bed methane, Bakken flared gas, and coke gas or the equivalent from modified power plants. A new take on railroad tank car management to compete with pipelines, and actually add value to petroleum liquids, which are fairly inefficient in refineries.

So what's up with this in New Jersey? Two small refineries in Linden and Elizabeth are now closed, but there is already a Tosco landfill methane line at work to provide the plastics industry in that area. A good bet that Primus will reposition all this into aviation fuel production, a la the Hercules refinery in Philly, which US Air took over to produce jet fuel for its own use.


"Current aircraft engines feature valve gear components which are designed for compatibility with the leaded ASTM D910 fuels. In such fuels, the lead acts as a lubricant, coating the contact areas between the valve, guide, and seat. The use of unleaded auto fuels with engines designed for leaded fuels can result in excessive exhaust valve seat wear due to the lack of lead."


They might use isobutanol, gasoline and TEL.

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