Two studies conducted by environmental divisions in Louisiana and Texas uncovered volatile organic compound (VOC) emissions from barges in Louisiana and from storage and terminaling facilities in Texas.
Bruce Hammatt of the Louisiana Department of Environmental Quality and Adam Bullock of the Texas Commission on Environmental Quality discussed the studies at the Platts Refined Products Storage and Transportation Conference October 16-17 in Houston, Texas.
The Louisiana study of barge emissions defined cargo vapor leakage as permitted, or authorized emission and unauthorized or illegal emission. Examples included pressure relief valves, permitted emission sources, as well as other locations. The barges contained products such as pygas, transmix, unleaded gasoline, raffinate, natural gas, crude oil, light cycle oils, and naphtha.
Preliminary results of the study indicated that as a tank became empty, more leaks occurred. Use of infrared cameras detected an abundance of leaks from the barges photographed.
Hammatt said he was amazed at the number of releases that were seen, particularly since the study was conducted on a cool day when emissions are typically lower.
He pointed out that barges are not designed to handle emissions, noting they are constructed with emphasis on preventing product from leaking into the water and protecting against explosions.
Based on the study, preliminary results indicate that at least 3.1 tons of emissions are occurring per day.
In Texas, results from studies using infrared camera were conducted to help in determining if there are significant volatile organic compounds (VOC) emissions that were previously unknown or unaccounted from unconventional sources, Bullock said.
The cameras also are used to help the agency identify individual sources of emissions in areas with elevated air concentrations of pollutants.
Dubbed the “Find it and fix it” program, the study focused on barges, loading operations, floating roof storage tank landings, and oil field storage tanks.
Emissions were noted from barges that were either docked and being loaded or unloaded, in a barge parking lot, and in transit. "Plumes were primarily noted at the hatches and pressure-relief vents," Bullock said.
After the study, all of the identified regulated entities were contacted and asked to provide emission information. Based on findings, bulk terminals in at 52 sites were requested to revise their emission reports due to landing and refilling emissions from floating roofs. Some bulk terminals have committed to make the requested reductions in the amount of emissions due to landings, he said.