There is certainly a lot of conversation and there is a lot going on in this arena. Im going to try to get to the bottom of this story and give you some background on the good and the bad – as well as the possibilities.

Fuels First

On the fuels side, biodiesel has become very popular in recent days. In the United States, it is manufactured mostly from soybeans, which are esterified with methanol to create a fuel that provides energy at similar levels to current hydrocarbon based diesel fuels. Equipment OEMs are being cautious at this point and are looking at blends of biodiesel and conventional fuel to power their vehicles. There is even a cottage industry in collecting used cooking oils – would you like fries with that? – for use as fuels.

On the gasoline side, methanol and ethanol are being promoted as fuels to make the United States energy independent. Almost all gasoline being sold in the country contains 10 percent ethanol as a fuel additive to reduce emissions. While not as energy efficient as gasoline (it produces about 30 percent less energy per pound), ethanol is being promoted as a means to wean the American economy from foreign crude oil.

In order to do so, however, it is necessary to develop large sources of ethanol. Currently, corn is the basis for fuel-grade ethanol, which has prompted a major discussion about the issue of food versus fuel. I recommend that you read up on it as it is a significant issue for everyone, not just the United States.

The Lubes Side

Not surprisingly, biofuels have led to a lot of work in the engine lubricants area. Oil marketers and additive manufacturers, along with the major OEMs, are working to develop lube products capable of dealing with some of the unique challenges biofuels bring to the game. However, these lubricants so far are mostly formulated using petroleum base stocks. As far as lubricants of biobased content are concerned, there has been a steady steam of new products coming into the marketplace for more than two decades. Gear oils, metalworking fluids, greases and hydraulic oils, just to name a few, have all been formulated with biolubricant stocks, some from animal sources but most from plant based materials.

Biolubricant base stocks are very diverse in themselves. High oleic sunflower oil, soybean oil and genetically engineered plant oils (much controversy here) are a few of the many choices available to compounders and blenders.

Naturally, biolube base stocks have some unique characteristics that make them a valuable addition to any oil marketers portfolio. They offer an environmental advantage in that they are less likely to pollute rivers and lakes. Of course, the degree of environmental contamination is dependent on the additives that may be present in the new oil and/or contaminants in the used oil.

Biolube base stocks also have some interesting properties such as relatively high viscosity index, inherent friction reduction, and good load-carrying capabilities. These properties can be used to advantage in such applications as gear oils and hydraulic fluids.

To summarize: Biolubes are environmentally appealing; they offer some performance enhancements in certain applications; they are attractive as a selling tool. So far, so good.

Engine Lubricants

When we get to the subject of engine oils formulated with biolube base stocks, we hit a roadblock. To date, there is no engine oil formulation meeting current API/ILSAC specifications that is based on biolubes. The question is, why? Its a long and complicated discussion so get some popcorn and find a comfortable place to sit, because were going to be digging pretty deep.

As you are aware, the oil/additive industry and engine manufacturers have worked out a system to develop and approve new products for the needs of modern engines. At the present time, gasoline engine recommendations are included in the oil industrys API SM category and the auto industrys ILSAC GF-4 specification. These two categories are essentially identical (GF-4 includes gains in fuel economy), and describe an oil which meets a number of industry devised and defined performance tests. Broadly, the engine tests cover wear protection, oxidation resistance and deposit control. In addition there are a number of bench tests which measure resistance to water (emulsion), foaming, rust prevention and volatility.

Since biolubricants are not found in any of the other API base stock types, they are classified as Group V. This doesnt mean anything until you try to determine whether or not there are any base stock interchange guidelines that can be incorporated into your engine test program. For the sake of this discussion, lets assume that we are going to develop a new engine oil based on a Group V biolubricant base stock.

The table below is laid out to show the standard engine oil tests, the parameters each measures, and the predicted performance hurdles faced by a biolubricant based engine oil. The predictions are mine, and are based on what the test measures and what additive tech-nologies I believe would be needed.

In the end, the issues are two-fold. First, is the bio-lube base oil oxidatively stable enough to handle the high temperatures (over 250 degrees F) of the Sequence IIIG engine test? The additive system will have to be extremely robust to account for what is essentially a highly unsaturated oil molecule. Unsaturation equals susceptibility to oxidation and even thermal stress.

Second, is the biolube molecule hydrolytically stable enough to handle the water and high temperatures that it will encounter in the crankcase? The plant esters used in biolubes are subject to hydrolysis, the tendency to absorb water and break down. Hydrolysis of the biolube will release a number of really bad actors into the crankcase, such as acids, aldehydes and oxidation accelerators. They will promote oxidation and deposits as well as interfere with the function of some of the additive components. In addition, gel formation will occur which will mess up the distribution of oil to the rest of the engine.

Cracking the Puzzle

So now the question is: Can a biolube based engine oil be formulated successfully? That depends on how you want to go about it. Especially, as shown above, oxidative resistance holds the key.

If you choose to use some already-established materials (e.g. polyol esters) you may be able to develop successful GF-4 products. Thanks to their polarity, polyol esters have been used as a component in polyalphaolefin based synthetic engine oils for a number of years. Since PAO is not a good solvent, the primary purpose of the esters is to provide sufficient solubility to the additive system. They also provide some good seal-compatibility properties. Polyol esters or some similar material may give biolubes the enhanced performance needed to successfully meet GF-4s requirements. Many of them are able to provide satisfactory performance, but they are extremely expensive and that cost will have to be justified.

We havent mentioned heavy-duty engine oils. The issues there are even more difficult, given the higher temperatures and longer-duration tests demanded for API CJ-4 performance. At this point, heavy-duty engine oils based on biolubes appear to be even further out than passenger car engine oils. However, given the desire of the farm implement industry to support their customers, I expect that lots of work will be done on just such formulations.

The bio marketplace is really active. Both fuels and lubes are gaining traction in many areas. Fuels are growing, especially in the farm belt, as states enact legislation to foster their use. Lubes are a bit behind fuels but there is plenty of activity in non-engine oil applications. Both fuels and lubes present some great opportunities as well as some significant hurdles.

Engine oils – which represent the biggest segment of the 2.5-billion-gallon U.S. lubricants market – are a tempting target for biolube manufacturers and marketers. There are major challenges in both gasoline- and diesel-powered engines, which will be solved eventually. Until then, it looks as though conventional (and not-so-conventional) petroleum base stocks are the base fluids of choice.

But dont go away for long, because Im sure biobased engine oils with API credentials will be in the marketplace soon. It just needs someone to come in with hard data showing they meet the industry requirements.