Submitted to: Industrial Crops and Products
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/20/2006
Publication Date: 10/10/2006
Citation: Erhan, S.Z., Sharma, B.K., Perez, J.M. 2006. Oxidation and low temperature stability of vegetable oil-based lubricants. Industrial Crops and Products. 24:292-299. Interpretive Summary: The uncertainty in supply of petroleum based products and their unfavorable impact on the environment has created a demand for eco-friendly lubricants. Vegetable oils are promising candidates for eco-friendly lubricants, because of the advantages like naturally renewable resource, environmentally safe, good lubricity and viscosity-temperature characteristics. Vegetable oils have some shortcomings like poor low temperature flow properties and oxidation stability. This paper presents a systematic approach to improve the oxidation and cold flow behavior of vegetable oils by using high-oleic vegetable oils along with chemical additives, which can inhibit oxidation and improve cold flow properties. Among the various possible avenues available, this combination of using chemical additives and high-oleic vegetable oils offer the best option for achieving the ultimate goal. Biobased lubricants formulated using the above approach exhibit superior oxidative stability, and improved cold flow properties compared to commercially available industrial oil such as bio-based hydraulic fluids. The above biobased lubricant can be used for applications such as hydraulic fluids, metal working fluids, crankcase oils, drilling fluids, two-cycle engine oils, wear resistant fluids and greases. This approach will improve the agro-economy of the locally grown renewable resource with the new markets for soybean oil.
Technical Abstract: The search for environmentally friendly materials that has potential to substitute mineral oil in various industrial applications is currently being considered a top priority research in the fuel and energy sector. This emphasis is largely due to the rapid depletion of world fossil fuel reserves and increasing concern for environmental pollution from excessive mineral oil use and their disposal especially in loss lubrication, military applications, and in outdoor activities such as forestry, mining, railroads, dredging, fishing and agriculture hydraulic systems. Vegetable oils have a capability to contribute towards the goal of energy independence and security due to their naturally renewable resource. Vegetable oils are promising candidates as base fluid for eco-friendly lubricants because of their excellent lubricity, biodegradability, better viscosity-temperature characteristics and low evaporation loss. Their use, however, is restricted due to low thermo-oxidative stability and poor cold flow behavior. This paper presents a systematic approach to improve the oxidation behavior of vegetable oil derivatives using pressure differential scanning calorimetry (PDSC), Rotary Bomb Oxidation Test (RBOT), and cold flow behavior using pour-point studies. Among the various possible avenues available, the combination of chemical additives and high-oleic vegetable oils offer the best option for achieving the ultimate goal. Vegetable oil-based lubricants formulated using the above approach exhibit superior oxidative stability, and improved low temperature properties such as pour points compared to commercially available industrial oil such as bio-based hydraulic fluids. The above vegetable oil-based formulations compare at par with petroleum-based lubricants for use in high-temperature and high-pressure applications and often outperform the competition in some of its properties.