Emission of Volatile Organic Compounds from Drum-Mix Asphalt Plants

摘要

This research program was undertaken in order to develop a quantitative estimate of the emission of volatile organic compounds (VOCs) from drum-mix asphalt plants. The study was carried out by field sampling of five drum-mix plants under a variety of operating conditions. Included in these plants was a plant that processed a mixture of recycled pavement of virgin aggregate, and a plant that employed a wet scrubber, which was tested both at the stack and also upstream of the scrubber to determine if wet scrubbing provides any significant VOC removal. The sampling method used was EPA Proposed Method 25, modified to filter out particulate emissions which would interfere with the laboratory determination of VOC concentration in the collected samples. Results are the VOC emission factors for drum-mix plants are on the order of 0.1 to 0.4 pounds of VOC (as carbon) per ton of asphalt concrete produced. VOC emissions appear to be independent of operating parameters, over the normal range of plant operation and within the limited scope of the statistical testing employed. It appears that a wet scrubber reduces VOC emissions somewhat but the reduction is difficult to quantify because of variation in the results. The nationwide emission of VOCs from all drum-mix asphalt plants is estimated to be about 20,600 tons per year.