Eighth-graders at Centennial Campus Magnet Middle School in Raleigh tried their hands at being field chemists at the NCDA&CS Motor Fuels Lab display at RiskFest, an annual event at the school that allows students to participate in hands-on activities that enhance the learning process on managing risks. Its goal is to inspire participants to become better managers of agricultural, environmental and energy-related risks. Student chemists tested the octane levels of gasoline using Zeltex, a fuel analyzer that uses infrared light to read the octane level of gasoline.
“The lab has nine field chemists who check gas at stations across the state,” said Marcus Helfrich, a dual-role lab and field chemist. “Purchasing fuel for your vehicle is a significant expense, and using the wrong type could potentially damage your vehicle. Mistakes can happen during delivery and we want to ensure that consumers are getting the right product.” Last year the lab tested about 22,000 samples at the lab in Raleigh and about 7,400 in the field.
Standards Division field chemists also check ethanol levels in gasoline at gas stations. Students used a water strip test to measure the percentage of ethanol in gasoline. Students added 10 milliliters of water to 100 milliliters of ethanol-containing gasoline and mixed the solution. The increased volume of the lower-water layer after mixing due to the “stripped” ethanol can be used to determine the original concentration of alcohol in the gasoline sample. In a separate experiment, a sample of gasoline that contains 10 percent butanol, another bio-derived alcohol made from corn products, is tested using the same procedure. Unlike the results from the ethanol-containing gas, the butanol remains mixed with the gasoline. “Since ethanol is more prevalent in our gas we’ve had an increase in the number of complaints of water in gas. One reason is that ethanol is water-sensitive and can easily be separated from the gas,” Helfrich said. “Butanol is not as water-sensitive as ethanol and, as a result, has recently started to be evaluated for use in gasoline.”
The NCDA&CS Standards Division Motor Fuels Section is responsible for enforcing motor fuel and heating fuel quality standards. Field chemists check for cross-contamination, octane levels and ethanol levels at gas stations across the state. The lab also tests experimental fuels for companies. Recently, the lab tested oil made from tires and an oil made from plastic bags and computer chips. Both oils had too low of a flash point to be labeled for use.