The Advantages and Disadvantages of Vegetable Oil as Lubricant

August 14, 2014

The Advantages and Disadvantages of Vegetable Oil as Lubricant

For lubricants to be eco-friendly, marine lubricants in particular, they should be non-toxic and harmless while delivering the expected performance of a normal lubricant. This being said, vegetable oils can be used as lubricants particularly marine lubricants for industrial and machinery lubrication in their natural forms. Using vegetable oils can be beneficial one of which is that vegetable oils have excellent lubrication compared to mineral oil. Their lubricity is so powerful that tractor transmissions, they add friction materials to minimize the clutch slippage.

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Vegetable Oil Advantages

One of the most important advantages of vegetable oils is their biodegradability. They are generally renewable and less toxic, reducing the dependency on imported petroleum oil. Vegetable oil has high flash points at 326 degrees C (610 degrees F) than a flash point of 200 degrees C (392 degrees F) for most mineral oils. Flash points are the temperature to which a combustible fluid should be heated to give adequate vapor. This is to form temporarily a flammable mixture with air when a small flame is applied. This temperature is under specified conditions by ASTM D92. Vegetable oil has very high viscosity index (VI). Viscosity index is a frequently used measurement for change of fluid’s viscosity with temperature. The higher the viscosity index, the smaller the change in viscosity with temperature. A VI of 223 is usual for vegetable oil as compared to 100 VI for most mineral oil. In short, high VI oil changes less with temperature compared to oil with low VI.

Vegetable Oil Disadvantages

On the flip side, vegetable oils in their natural form don’t have enough oxidative stability. Having low oxidative stability means the oil oxidizes quickly during use if untreated. This becomes thick and polymerizing into a consistency like that of a plastic. To address this situation, chemical modification of vegetable oil or using of antioxidants is done. However, this can increase the price. Apart from that, vegetable oils have high pour point. This is the lowest temperature at which oil is observed to flow when cooled under condition. This is prescribed by test method ASTM D97. The pour point problem can be solved through winterization in which chemical additives are added and blended with other fluids that have lower pour points.

To measure the toxicity of vegetable oils, variety of tests is used that involves other organisms. The toxicity increases once additives are included as vegetable oils show little toxicity in their natural forms.

Hamburg Trading House is an authorized Shell Marine lubricants distributor in the UAE. In addition to Shell Marine Products, they are representing Tribomar in the United Arab Emirates for their Oil Management Systems and Tribomar Test Equipment. Hamburg Trading House is focusing on Marine business only offering its customers outstanding services at competitive prices.

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