APC Technologies (APC) installed multiple Ultra High-Efficiency Filter (UHF®) systems at a large asphalt terminal located in Western Canada. The air pollution control systems were installed to achieve two objectives:
- Greatly reduce hydrogen sulfide (H2S) concentrations in the breathing zones of operators, which were at unsafe levels; and
- Provide oil mist control, particulate control, and visible emissions/opacity control on the mist and smoke escaping from asphalt terminal activities.
The client had tried a simple collection system for the asphalt fumes, which failed due to an inability to handle liquid and solid particulate in the gas stream. APC’s UHF® filter systems, in comparison, are made for removing messy, oily, sticky fine particulate such as that from asphalt tanks and loading activities without any plugging problems.
At the site, four UHF® filter systems were installed, each system handling two asphalt loading stations. Each UHF® filter system is comprised of a UHF® filter unit, system blower, instrumentation and NEMA 4X control panel. The four systems recently were commissioned and are achieving all project objectives.
APC has been fabricating and installing air pollution control systems at asphalt terminals and refineries across North America for nearly two decades. At these sites, vent gases from asphalt storage tanks and asphalt loading activities are treated using APC’s uniquely-suited UHF® filter unit for oil mist control and particulate control, and – where H2S, odor and/or VOC control is also needed – its CarbonPure activated carbon adsorption systems to remove these latter emissions. The systems can address the following objectives:
- Greatly reduce employee, truck driver, and railcar operator exposure to hydrogen sulfide (H2S);
- Provide odor control and eliminate odor complaints from neighbors;
- Eliminate visible emissions / opacity caused by escaping mist of condensed hydrocarbons when asphalt fumes leave storage tanks or are generated during loading of asphalt into trucks or railcars; and
- Provide VOC control prior to emitting vent fumes to atmosphere.
UHF® filter units are unique among particulate control devices as they are specifically designed for applications with very fine, sticky condensed fumes and particulate such as condensed asphalt fumes. The unit uses dry filter media in roll form, providing very high removal efficiencies (i.e., 98-99%+) including on submicron particulate. Submicron droplets collected by the filter combine to form large raindrop-sized droplets, which collect in the bottom tank of the filter unit. The filter avoids plugging and maintains steady air flow by automatically advancing a clean section of filter media into the filtration chamber when the previous filter section becomes caked and is no longer effective. The filter unit operates within steady differential pressure and air flow rate bands until the entire filter roll is used. Filter rolls are changed in a few minutes with no system downtime.
For asphalt applications that require VOC control, H2S emission control, and/or odor control, exhaust gases pass from the UHF® into a CarbonPure vessel containing activated carbon media for removal of gas-phase H2S, other odorous compounds, and VOCs.