Ten years ago, barely 8 percent of polyalphaolefin supply counted as high-viscosity fluids, in grades of 40 and 100 centiStokes. The world had about 385,000 metric tons a year of capacity, and the market was dominated by fluids weighing 4 to 10 cSt.
Today, global PAO capacity has surpassed the 500,000 t/y mark. Nearly a quarter of this API Group IV base stock is high-vis and more tonnage is being teed up. Even the molecules themselves have become beefier; lubricant blenders can get their hands on weights like 135, 150 and even 300 cSt.
The next glug of high-vis PAO is coming from Ineos Oligomers, which has been taking a step-wise approach to opening up its PAO taps. It began making high-vis PAO at a pilot plant three years ago, then via a toll manufacturer. In January, the company will open a new PAO unit at La Porte, Texas, near Houston.
Using metallocene catalyst technology, La Portes high-vis unit will have initial capacity of 20,000 metric t/y. Since La Porte has two trains that already make low-vis PAO, the new unit will be able to exploit the sites synergies. Its also designed for easy debottlenecking to keep pace with demand for the high-vis stuff, which is sold under the Durasyn brand in 50, 100 and 135 cSt grades.
Not stopping there, the chemical giant in May gave the thumbs-up for a new, full-range linear alpha olefins unit at its chemicals complex in Chocolate Bayou, Texas. Due in 2018 and sized for 420,000 tons a year, this will be the companys third LAO production site, after Feluy, Belgium, and Joffre, Canada.
Derived from ethylene, LAO is the critical hydrocarbon feedstock for making PAO, so being upstream-integrated is an advantage for Ineos. While La Portes lighter LAOs will go into surfactants, detergents and polyethylenes, the fresh injection of C10 (decene) through C14 hydrocarbons means Ineos can plow ahead with building another world-scale, low-vis PAO train. That facility likely will stream in 2018 or 2019. While its location has not been disclosed, observers predict either La Porte or Chocolate Bayou will get the nod.
Meanwhile, things are getting heavy over at ExxonMobil Chemical, too. It recently threw onto the scales SpectraSyn Elite 300, a 300 cSt material with a viscosity index of 241.
This material comes from the 50,000 t/y high-vis mPAO plant that ExxonMobil inaugurated in 2014 in Baytown, Texas. Already producing 65 and 150 cSt PAO, Baytowns highly selective metallocene platform is now being leveraged to make even higher vis products, says Brad Rinderknecht, global marketing manager for synthetics.
Jack Hazel, global market development manager, added that the new grade has more than weight going for it. He cites it for exceptional film thickness, shear stability and temperature properties that are ideal for formulating industrial gear oils, engine oils, greases and industrial driveline lubricants. These properties allow blenders to make lighter-viscosity finished lubricants which save energy without sacrificing wear control, he said.
Weve been doing the development work on SpectraSyn Elite 300 since fourth-quarter 2015, including industrial field trials back in January and March, Hazel continued. The new PAO is very viscous, yet has excellent cold-temperature properties, with a pour point of -33 degrees C. Weve seen next-best alternatives to PAOs that become solid at -25 C, so thats very good.
ExxonMobil staff chemist Mike Sheehan said this extra-heavy PAO will appeal to blenders who need to formulate fluids ranging from ISO VG 32 to VG 1,000 and beyond. You cant get into that higher range, like ISO 1,000 or 1,500, if all you have is a 40 cSt PAO, he pointed out. You would need to include a 52 percent treat rate of the high-vis component. With the 300 cSt fluid you wont need such high treat rates, so this option will help lower the customers overall cost of raw materials. Plus, a lot of our customers say they only have one tank for storing high-vis PAO – this will be the answer.
In fact, you will need 40 percent less [high-vis] material to blend an ISO VG 320 oil if you use a 300 cSt base stock in place of a 40 cSt base stock, emphasized Rinderknecht, so you get blending efficiencies, and you get a better product. As an example, he pointed to shear stability measurements in the rigorous KRL tapered roller bearing test, which is referenced in heavy gear oil specifications. Using SpectraSyn Elite 300, the test ran at 20 degrees C for 100 hours. Yet the shear loss at the end of the test was below what the test can detect, he declared.
Chevron Phillips Chemical also is seizing on strong demand for high-vis PAO in lubricants and greases. Possessing its own proprietary metallocene process, Chevron Phillips makes mPAOs in 65, 100 and 150 cSt weights. It has capacity now to make 9,000 t/y of high-vis PAO at a tolling plant in Pasadena, Texas, plus 108,000 t/y of low-vis capacity in Cedar Bayou, Texas, and Beringen, Belgium.
In a presentation to the Society of Tribologists and Lubrication Engineers in May, Ken Hope, the companys global PAO technical services manager, reminded listeners that high-viscosity base stocks of all kinds, including PAOs, are seeing strong demand because bright stock supplies have dwindled with the loss of API Group I base oil plants over the past decade. Besides PAO, there are alternatives including heavy neutrals, polyalkylene glycol, alkylated naphthalene and polyisobutylene, but the deficit is quite significant, he said.
For those seeking heavyweight alternatives, he said the performance advantages found in metallocene PAOs make them a strong contender. Chevron Phillips Synfluid 100 cSt mPAO, for example, has excellent oxidation stability, a pour point of -42 C, and V.I. of 190 – which is 20 points higher than a conventionally made PAO of the same vis grade.
Recent research continues to turn up other advantages, too, Hope reported. Results in the ASTM D892 foam release test showed that Synfluid 100 mPAO has less foaming tendency than conventional PAO. Thats important for many lubricants, including hydraulic fluids. Foam doesnt support a load – you cant pump a foam – so foaming characteristics are important for lubricant formulators, Hope said. Why is the foam lower for mPAO? In fact, we dont know – but the tests do show theres a difference. More research is under way to answer this intriguing puzzle.
Theres also the question of thickening efficiency. When blended with low-vis PAO or mineral oil, mPAO can help formulators to reach a higher V.I. and lower pour point (less than -50 C), the data show. The high-vis component is often a higher cost component, Hope interjected, so if you can use less of it, youll improve your costs.
Although high-vis PAO is grabbing the limelight today, Chevron Phillips is also investing in low-vis capacity. At the end of March, its board gave the final go-ahead for a 10,000 t/y low-vis expansion at Cedar Bayou, a gain of about 20 percent. Construction is under way and start up is expected in mid-2017. And since Chevron Phillips is upstream-integrated, this expansion will get ample feedstock from Cedar Bayous recent 100,000 t/y boost in normal alpha olefins capacity.
Having more options is increasingly important as the lubricants market moves to higher-performing products, according to ExxonMobil Chemicals Brad Rinderknecht. 2015 saw record sales of PAO, and they were steady through the first quarter of 2016, even slightly above whats typical in all regions, he said. For a while last year there was a lot of concern about low-vis availability, but the market seems balanced now.
In fact, the pivot to high-vis mPAOs helps to ease tightness in the market, he added. Most companies in this market like to use decene, which has been structurally short, said Rinderknecht. So producers who rely heavily on decene can have issues.
By contrast, mPAO producers often can employ a spectrum of hydrocarbons, from C8 to C12 or C14 – which means fewer feedstock limitations. If everyone was using decene alone, Rinderknecht estimated, structurally there would be 150,000 tons less of PAO supply available – thats how much wed be short of global PAO demand.
Fortunately, with new LAO and PAO supplies making their way to market, the threat of structural shortage seems to be contained – for now.