June 29, 1998

NC State Engineer's Research to Aid Oil Industry, Environment

In a nation that relies heavily on the use of internal combustion engines in its automobiles, trucks, airplanes and other machines, the production of oil and gas is of paramount importance. But extracting and refining crude oil often makes a strong impact on the environment--so much so that President Clinton recently extended the ban on off-shore drilling for 10 years. Efficiently producing crude oil from deep sea reservoirs--crudes that frequently contain heavier and less volatile materials--is becoming increasingly difficult. For these and other reasons, oil companies are looking into better ways to produce, transport and refine petroleum that minimizes negative environmental impact. At NC State University, Dr. Peter Kilpatrick conducts research that will make crude oil production and refining more efficient and better for the environment.

Kilpatrick, professor and associate head of chemical engineering, studies the properties of various heavy crudes and the ways in which mixtures of crude and water and other contaminants respond to the production process.

The crude oil extracted from wells is a mixture of oil, salt, water, rocks, waxes and asphaltenes--large and complex organic materials in crude oils. Using temperature and solvent changes, Kilpatrick can cause the contaminants in the crude to partition selectively, making them easier to remove. The processes he has developed have the potential to make crude easier to extract from the well and easier to refine.

"As crude is removed from a production well, it frequently becomes too thick due to the drop in temperature of the crude or due to the formation of an emulsion caused by the asphaltene and water content," says Kilpatrick. "It can make extraction almost impossible and the resulting crude is more difficult to refine."

During the extraction of crude oil from a well, an emulsion is formed when asphaltenes stick to the outside of extremely small water droplets in the crude, causing a stabilized mixture of oil and water. In crude oil production, stable emulsions make processing more difficult because the contaminants are suspended in the crude and because the thick emulsion is more difficult to pump out of the well. To remove the contaminants and to make the crude more liquid, the emulsion must be broken down often by stimulating the production well with added solvent or increased temperature.

"By understanding how and why emulsions form in crude and how the different components, such as the asphaltenes, work in the formation of crude oil emulsions, we can find ways to break them down and make them work to our advantage," says Kilpatrick. "This knowledge is helpful both in the process of extracting oil from wells as well as in the refining of the crude oil at the plant."

In addition, this oil refinery research promises to help the oil and gas industry improve its production while reducing the impact on the environment. Crude taken from deep sea wells is often contaminated with salt water. If the refinery processed the crude oil without first removing the salt, the refining equipment would quickly corrode causing costly repairs. The current technique for removing salt from crude to prevent equipment corrosion requires refineries to use thousands of gallons of fresh water to "wash" the salt water droplets from the crude before starting the refining process. The resulting water is contaminated with salt and other impurities, and it must be cleaned before it is released into the environment. Kilpatrick has found that by manipulating the makeup of crude oil, he can reduce the amount of fresh water needed to remove the salts and other impurities from the crude oil.

Kilpatrick is one of only two or three university researchers in the United States developing these techniques for manipulating emulsions in crude oil extraction and refining. His research is funded primarily by the Petroleum Environmental Research Forum (PERF), a consortium of oil companies, including Exxon, Shell, Mobil, Chevron, Arco, Texaco, and several others, formed to fund research into crude oil production in relation to the environment.

"While this research has little immediate impact on the consumer in the form of reducing gas prices at the pump, the knowledge gained concerning emulsion formation is of significant importance to the oil companies and will ultimately affect American consumers," says Kilpatrick. "The processes developed from this research will certainly help make production more efficient, resulting in an economic benefit, and help reduce the impact of production and refining on the environment."

Media contacts: Dr. Peter Kilpatrick, (919) 515-7121, peter-k@eos.ncsu.edu

Jennifer Weston, (919) 515-3848, weston@ncsu.edu

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