Line wash, sometimes called flush oil, is a reality of lubricant manufacturing, one that most are aware of but few speak about. The volume generated each year is too great to ignore, but at the same time its difficult to find an economical outlet for line wash within the confines of industry quality and approval testing protocols.
Because of this, many tend not to want to speak about line wash. A few are speaking out though. Distributors have become increasingly vocal in their belief that a significant volume of line wash – some from independent blenders but even more from major oil companies – is being dumped on the market and resold as finished lubricants. Unhappy oil marketers say these off-spec fluids are finding their way into bulk tanks and containers at installers, on store shelves and elsewhere, and at prices that hurt legitimate products.
Rather than ignoring line wash, or painting it as a pariah, maybe now is the time to talk about it. Maybe line wash should receive more focus from our industry, to understand the issues associated with managing it and identify how to better handle this byproduct. Lets start by looking at what line wash is, and where it comes from.
For those that dont know, line wash in the context of this story is the material used to flush the lines/pipes when a blender switches production from one type of lubricant to another. As an example, when a blender switches from making SAE 10W-30 passenger car engine oil to making a lighter-vis SAE 5W-30 (with both meeting API SM/ILSAC GF-4), a certain volume of 5W-30 must be pushed through the lines to assure that everything coming out after the switch is 5W-30 instead of a commingled mixture of 10W-30 and 5W-30.
Such change-ups from one batch of lubricant to another happen all the time, generating a significant volume of line wash in the process. In fact, Petroleum Trends International estimates the volume of line wash produced by the majors alone is at least 10 million gallons a year. The amount of line wash generated in any particular blending facility is a function of many variables: the blending equipment utilized, the piping configuration, viscosity grade slate swings, and contamination tolerances, to name a few.
But regardless of how much, lubricant blenders generate it and when they do, some segregate and isolate their line wash into pools of related products. Theyll have certain tanks that receive and store all line wash generated while making various grades of passenger car engine oil, and other tanks to hold line wash comprised of differing grades of heavy-duty engine oils. The same can be done with line wash coming from hydraulic fluids, automatic transmission fluids and other groups of products with relatively compatible and comparable additive treat rates and base oil quality levels and viscosities.
One reason line wash can be segregated this way is due to the planning that goes into assuring the greatest efficiency when blending a sequence of batches. Products blended in successive batches are purposefully selected to be relatively close in their composition and targeted specifications. As such, the back-to-back blends can be transitioned more quickly and require the use of less line wash. This would not be the case if one were jumping from making ATF to making engine oil in quick succession, for example. Such a switch could require a considerable volume of line wash to simply clear the lines of the red dye used in the ATF (if the dye were introduced in the blend line).
So here we are with a significant volume of line wash generated every day by lubricant blenders. And keep in mind, this line wash is far from the usual slop oil, waste oil or cement kiln fuel. Instead, if we are talking about a line wash from engine oils with differing viscosity grades, for example, its often the output of state-of-the-art blend plants and made with quality base oil and performance additives. This soup might be commingled SAE 5W- and 10W-30 passenger car engine oils; 15W-40 and 10W-30 heavy-duty engine oils; or a number of other combinations within a family of products. Further, these commingled flush oils contain additive systems that meet current specifications, and while the viscosity is out of spec, it may be adjusted/corrected to meet SAE grade for a specific product.
So where is the issue, where is the rub with flush oil? With adjustments to bring viscosities in line, wont these fully additized products meet SAE grade? If so, why not sell this juice as an API-licensed product?
For authoritative answers, we went to the American Petroleum Institutes engine oil manager, Kevin Ferrick. He replied, As far as the sale of line wash is concerned, a blender might find some use for it, but we cant think of many. We dont think it could be used in an API-licensed oil. The variability of the line wash would be too great to allow it to be used in a licensed product.
That leaves us with big questions – and the topic of next months column. If line wash has value, what happens to it, and where does it go after blenders produce it? Does some of it truly end up sold as on-spec engine oil? And just as importantly, what can industry do to understand the issues associated with managing and legitimately monetize the value of line wash?