[Higher] efficiency will lead to machinery and equipment that wont need to be replaced as often and [that operate for] much longer oil drain intervals. It opens up big opportunities for lube manufacturers to make more advanced lubricants, said Reid-Peters, who is based in the companys Fawley, U.K., office.

PAOs to the Forefront

Today, one of the best approaches to manufacturing cutting edge lubricants and fluids is the use of polyalphaolefin base stocks (PAOs), he said. PAOs have huge performance advantages because they can be used in a wide range of applications, they can operate over wide range of temperatures, and they have extended service life, lower maintenance costs and big opportunities for energy savings.

What makes PAOs so useful are properties that include high viscosity index, low temperature fluidity, low volatility and good oxidative and thermal stability. PAOs [operate with] lower traction force, and they reduce internal friction, so energy savings in many applications such as gears or rolling bearings are great, Reid-Peters said. Furthermore, because of their low toxicity, they can be used in pharmaceuticals as white oils or in the food processing industry as food grade lubricants. PAOs have good shear stability and generally have good compatibility with other oils and materials.

High viscosity index and low temperature fluidity give PAOs a wide operating range, allowing
them to be used in both extreme desert conditions and in severe arctic cold, according to ExxonMobil. Also, PAOs provide much longer oil life – three, four, five or even six times more – compared to mineral oil. Not changing the oil so often reduces maintenance costs, oil filter costs and waste oil costs. [In addition], their low temperature fluidity results in less churning, providing even more energy savings, Reid-Peters said.

The oil major found that all these properties provide great advantages in finished lubricants. PAOs can be used in a wide range of applications, from crankcase and jet engine oils to wind turbine oils, from hydraulic oils to plastic and rubber modifiers, skin and suntan creams.

History

Synthetic PAOs have been premier base stocks in lubricant formulations for over 50 years. Acid-catalyzed olefin polymerization was first carried out in the 1930s by the Standard Oil Co. in the United States and IG Farben in Germany, a former chemicals industry conglomerate. Both companies used the Friedel Crafts reaction, first demonstrated in 1877.

The first patent that explains the use of acid catalysts to oligomerize or polymerize linear alpha olefins (LAOs) to make PAOs was assigned to Gulf Oil Co. in 1953, Reid-Peters said. ExxonMobil began manufacturing PAOs in the 1960s, and lubricants formulated with PAO base stocks were introduced in the 1970s.

In the 1990s, base stock manufacturers began developing metallocenes to make PAOs and found that the resulting products were free from the isomerzation branches that are prevalent in PAO products, Reid-Peters said. These new regularly branched mPAOs showed some distinct advantages, and in 2009 our company began manufacturing them on a commercial scale.

In the mid-1990s PAO demand exceeded the available supply of the chemical 1-decene used to make LAOs, and some producers began developing PAOs based on mixed LAO technology to improve supply availability. Mixed feeds enabled more flexibility in the PAO supply chain and also provided a new tool for tailoring their properties, Reid-Peters said. Other marketers have since developed non-decene based PAO products.

Current Market Outlook

In Europe, only a few plants produce PAOs, most of them are for industry use, while high-quality automotive engine oils are primarily made with API Group II and Group III base stocks. European PAO plants include Chevron Phillips Chemicals 60,000 tons per year facility in Beringen, Belgium, ExxonMobil Chemicals 60,000 t/y Gravenchon, France, plant, as well as Ineos 120,000 t/y Feluy, Belgium, and Tatnefts 10,000 t/y Nizhnekamsk, Russia, plants. The latter is temporarily closed due to feedstock shortages.

In some regions, such as the Middle East or Europe, the new gas-to-liquid (GTL), Group III and Group III+ base oil capacities coming on stream will ease the short supply of PAO products, according to Infineums Trends 2013 Embracing Complexity presentation.

Market growth for low-viscosity passenger car engine oils raised concerns that current PAO capacity might be insufficient. This worry still persists in Europe, the Middle East and Africa, said Ian Field, Infineums senior representative, marketing and technology, at the RPI Lubricants Russia 2013 conference in Moscow in November.

[A]s decene feedstock remains tight, no additional low-viscosity PAO manufacturing capacity has been announced, said Field, who is based in the companys Abingdon, U.K., office. The only ongoing investment is focused on manufacturing high-viscosity index PAOs for use in industrial finished fluid applications.

The additive maker found that the availability of low-viscosity PAO in Europe is a concern as fuel economy spurs the introduction of thinner grades. As a result, SAE 0W-20 grades with high-temperature high-shear viscosity as low as 2.6 centiStokes are being developed and could require a significant amount of PAO to adjust viscometrics, he said.

It is unlikely that original equipment manufacturers will increase drain intervals to ease the impact of introducing expensive Group IV base oils, according to Infineum. The transition to alternative feedstocks to produce low-viscosity PAOs would be costly and reformulation would require significant resources and expense.

Furthermore, the change to alternative feedstocks to produce low-viscosity PAOs is not a trivial exercise. It would push lubricant suppliers to completely reformulate products because the interchangeability between PAOs based on different feedstocks is difficult, and any change in product formulations would require significant investment in time, money and people, Field observed. He added, It is highly likely that the extension of fuel economy [requirements] from factory fill oils to service fill oils will exacerbate the concern.

Infineum also found that new GTL, Group III and Group III+ capacities may ease the supply concerns, freeing up available capacity for applications that can only be formulated with PAO. However, to gain market share, it will be increasingly important to understand how to formulate these applications without PAO, or at least to minimize its use, he observed.

Finally, this can encourage marketers to reformulate products. It would mean that PAOs can be directed to specific applications, and marketers success will depend on the ability to remove or reduce PAOs in their lubricant formulations.