Presentation on theme: "Representatives: Nicki Hosey and Briana McDermott."— Presentation transcript:
Representatives: Nicki Hosey and Briana McDermott
Alternatives for Asphalt Synthetic Asphalt New Processes More efficient mixing and milling units In-line liquid mass flow meters On-line monitoring systems New safety equipment Improvements Modifiers Control pavement rutting, cracking, asphalt oxidation, and water damage Better Plants Cleaner Pavement warranties More common
Crude oil Pumped into a distillation tower --> 370˚C. Several hydrocarbons drawn by boiling points--virtually unusable otherwise Oil vaporizes and rises up the tower Vapor cools--molecules condense--heavier ones collecting at the bottom, lighter ones rising to the top. Heaviest hydrocarbons Highest boiling points, pulled from bottom of tower. Lighter hydrocarbons Pulled from higher locations as boiling points decrease. Stream pulled from bottom --> “reduced crude” --> further distilled in vacuum distillation tower into asphalt and heavy gas oils. Asphalt further processed for sale Paving, roofing, industrial use.
Two different types of plants --> different amounts of asphalt. Batch Plants: 350 metric tons per hour One batch (2-5.5 metric tons) --> 15-45 seconds Drum Mix Plants: Anywhere from 100 to over 900 metric tons per hour, depending on drum design
Emissions Dust Smoke Sulfur Dioxides Control/Prevention of Waste Electrostatic Precipitators Primary and Secondary Dust Collectors Enclosures Eliminates and increases heating efficiency of process
Materials from old pavements reprocessed with new materials Hot-Mix Recycling Cold-Mix Recycling Surface Recycling Over 95 million metric tons of asphalt paving material is recycled each year. America’s most recycled material
Must be kept hot to remain a liquid. 250°F and 350°F Loaded into a truck, barge or rail--pipelines cannot be used over great distances due to temperature constraints Heat transferred to surrounding environment Convection, radiation Asphalt surface temperature drops Cooler surface insulates interior mass. Air temperature, rain, wind, length of haul affect the characteristics and temperature of crust.