July 6, 2015

Naphthenic mineral electrical insulating oils

Abstract Much like the advice you receive about the correlation of the food you eat and your overall health, it’s all about what you put...

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Abstract

Much like the advice you receive about the correlation of the food you eat and your overall health, it’s all about what you put inside that optimizes the overall performance of an electrical transformer. The transformer industry is in constant search for improved, reliable and widely available insulating products to aid in the overall health of transformers, which in turn, will safeguard the overall reliability of the power grid. New technology is opening doors to greater insulating fluids source availability, while still meeting stringent guidelines.

Keywords: electrical transformers, insulating mineral oil, naphthenic, paraffinic, petroleum, crude, quality, hydroprocessing, inhibited, uninhibited

Electrical insulating oils are an integral component of transformers. In addition to being the insulating liquid for the electrical components, it serves as a medium to transfer heat away from the core, and helps maintain the water balance of the system. Many types of liquid have been used to perform this function over the last century, including petroleum oils, askarels, silicones, natural esters, synthetic esters, and synthetic hydrocarbons. Petroleum oils, more specifically naphthenic and paraffinic base oils derived from crude oil, have been the most commonly used liquids since the late nineteenth century. In the early days of electric transmission systems, paraffinic oils were used, but due to the high pour point from the presence of wax or normal paraffins in the oil, the oxidation product would precipitate at the bottom of the tank and cause obstruction in the transformer’s cooling system. Gradually, naphthenic oils, which are generally wax-free, became the predominant petroleum oil in use.

Naphthenic mineral oils are specialized products with desirable properties for specific applications, notably as electrical insulating oils. Naphthenic mineral oils are refined or purified from naphthenic crudes. Ergon Refining, Inc., (ERI) based in Vicksburg, Mississippi, USA, is an industry leader in the production of naphthenic insulating oils. Ergon has produced specialty oils for more than two decades, and is chosen by many major global power transformer manufacturers worldwide for its high quality, performance and proven reliability. Using severe hydroprocessing to produce naphthenic base oils, ERI is the world’s largest producer of specialty naphthenic oils with a capacity of up to 25,000 barrels of crude oil per day. While naphthenic crudes comprise only 5% of the world’s crude, naphthenic mineral oils comprise nearly 10% of the world’s base oil capacity. Naphthenic crudes are found on or near every continent, except Antarctica.

The vast majority of the world’s crudes are refined for the production of transportation fuels, not base oils, so it is very important that the correct crude is chosen and segregated to prevent contamination by waxy paraffinic crudes. Naphthenic mineral oil manufacturers are aware of these issues and institute measures to maintain the integrity of the oil throughout the process. For example, Ergon has two separate subsidiaries, Ergon Terminaling, Inc., and Ergon Trucking, Inc., to specifically address these contamination concerns.

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