Continental Shift Toward Naphthenics
Naphthenic base oil is often proposed as a replacement material for API Group I applications. But as capacity dwindles, can it plug the gap in a major Group I market such as Africa? In another look at the continents base oil landscape, Emeka Umejei explores the long-awaited rise of this base stock.
The decline of Group I base oil production capacity across the world is not news. One industry insider estimates that it shrank by more than 7.6 million metric tons per year between 2007 and 2015. Meanwhile, ExxonMobil Basestocks 2018 Industry Pulse report found that demand for Group I base oils had declined by a third compared with other base oils.
While this downward trend is seen in many parts of the world, it is not the case in Africa, where lubricant demand is about 1.5 billion liters per year and the market for automotive engine oils formulated with Group I base oils remains resilient. Engine oils formulated with this base stock comprise about 70 percent of the sub-Sahara African automotive lubricant market.
The average age of the vehicle fleet in countries such as Egypt, Nigeria, Kenya, Tanzania and Algeria is high, and the expectation that these countries would adopt emissions regulations en masse, leading to them transitioning towards Group II or III base stocks in search of greater fuel efficiency, is unlikely in the immediate term.
The exception to this Group I auto lube rule of thumb is South Africa, one of the most developed economies in the continent. However, while its newer vehicle fleet consumes higher grades of engine oil, it is a major market for industrial lubricants formulated with Group I oils. Globally, some 70 percent of industrial lubricants are made from Group I, with the majority being hydraulic fluids. Sasol, a South African energy and chemicals company, estimates that automotive lubricants account for 56 percent, industrial 40 percent and grease 4 percent of lubricant demand in then country.
In the face of declining capacity, African blenders will have to find a replacement for tightening supply of Group I that meets its viscosity and solvency characteristics. This alternative could be naphthenic base oil. Naphthenic base oils are refined from sweet, or low sulfur, crude.
According to data gathered by Transparency Market Research, the global naphthenic base oil market could reach U.S. $2.6 billion by 2025, up from $1.6 billion in 2016. But much of this growth is projected to be in North America, Europe and Asia-Pacific, rather than Africa.
Thomas Norrby, senior lubricants specialist at Swedish base oil and lubricants producer Nynas suggests naphthenics may be able to meet the needs of some applications that were once the traditional preserve of Group I. Applications include a variety of industrial oils, greases and metalworking fluids.
Properties that make naphthenic base oil a viable replacement for Group I include higher solvency than paraffinic oils with the same kinematic viscosity, fewer aromatic hydrocarbons, low sulfur, low wax content allowing for a low pour point and good emulsion stability.
The base oil slate mix offered, increasingly Group II and Group III, is driven by the needs of automotive engine oils, not by industrial lubricants needs, Norrby said. [Group I base oils that are] available in the market will not any longer be optimized towards, or even suitable for, industrial lubricant requirements because of too high aniline points.
The lower a base oils aniline point, the better its solvency. Solvency is a key property in industrial lubricant applications because it affects the oils ability to dissolve additives (usually polar species) and oxidation products. Solvency prevents varnish or deposit formation, which is critical in applications with very long drain intervals. Naphthenics aniline points can be adjusted to match to the Group I application it replaces, Nynas claims.
In the same vein, in lubricating greases, base oil solvency affects soap yield and the oil-soap interaction. While in metalworking fluid emulsions, better solvency increases emulsion stability.
Norrby also emphasised the viability of naphthenics for metalworking fluids applications and in grease production, noting that naphthenic-based greases have better shear stability which makes it a viable alternative to paraffinic oils in grease production.
The impact of the high solvency power of naphthenic base oils results in a denser structure and better mechanical shear stability, said Norrby.
Lithium greases account for 75 percent of world production but the market faces lithium shortage informed by the increasing use of lithium in the production of batteries for phones and electric vehicles. This, Norrby noted, has prompted the search for alternatives, inclduing aluminium or calcium sulfonate complex and polyurea, to be tried and established over a long period.
Emmanuel Ekpenyong, a lubricant expert based in Lagos, Nigeria, agreed that for metalworking fluids, transformer oils and a few other industrial oils, napthenic oils will continue to hold sway but added that they will not get to the point of eliminating or replacing Group I oils in Africa.
Ekpenyong also cautioned that while in some applications naphthenics can replace Group I base oils, they are not suitable for all uses. We all know the undesirable and inherent properties of naphthenics, which makes them undesirable for use in crankcase oils, he said. With the OEMs present demands on crankcase oils, which include increased viscosity index, lower volatility, etc., naphthenics oils cannot serve as a good enough replacement for Group I oils.
Yet, increasing automotive production and industrialization in the form of mining operations, construction, electricity infrastructure and even wind energy suggest that the continent may lead blenders to seek out naphthenics as an alternative to Group I base oil quicker than Ekpenyong anticipates.
ExxonMobil – one of the worlds largest producers of Group I base oil – projected that in Africa by 2023, demand for automotive lubricant would amount to 1.15 million tons per year, much of it formulated with Group I, while industrial lubricants would account for 720,000 t/y. This gives naphthenics plenty of scope to penetrate the industrial market.
Will Naphthenics Take Off in Africa?
Africa remains a strong Group I lubricant market and naphthenics advantages, such as high solvency and low V.I., may actually be a challenge. Low V.I. oils would become gradually less suitable for a newer vehicle parc. A base oils V.I. is determined by how much its viscosity is affected by changes in temperature, something which can see extreme fluctuations in parts of the continent.
The African market is also often driven by cost, and any Group I replacement must be available at a competitve price. While Norrby acknowledged Africans low-cost consciousness, he added that cheap materials are not always the best technical solution.
In industrial applications, we cant compare the pricing of oils with different performances – for example Group II versus naphthenics – and our customers generally look to the total formulation cost.
The benefits of Group I lead some industry insiders to speculate that there will always be demand for this foundational base oil.
As long as the third world remains the third world, with its rapidly expanding population, Group I base oils will never fizzle out of the lube space, said Ekpenyong.
There is more life in the old dog yet, and naphthenics still have a way to go before they can teach it new tricks in Africa.