Protecting our enviornment

Aerosol Can Recycling Facility Air Emissions

Unique to the Beacon Engineering EVAC aerosol can disposal/recovery systems is the capture and containment of the propellants – more than 95% -- providing maximum operator and plant safety and minimum emissions to the atmosphere. Unlike some other crushing units, there are no carbon filters which can be expensive and ineffective if not changed regularly.

S. C. Johnson Wax has been operating the Beacon EVAC II system since August of 1992. Excerpts from their report follows:

RE: Aerosol Can Recycling Facility Air Emissions

The aerosol can recycling facility has been successfully started up and is nearing full time operation. In accordance with SC Johnson Wax environmental goals, the new facility was designed with the overall objectives of significantly reducing Volatile Organic Compound (VOC) emissions and producing a recyclable waste stream. In order to characterize facility performance and meet permitting needs, air emissions testing for VOC’s was conducted during normal operational periods. Additionally, information obtained was used to calculate a mass balance on the facility in order to accurately determine the product/propellant capture efficiency of the new facility and characterize the recyclable steel obtained in the process.

Results

The aerosol recycling facility provides an average capture efficiency of 99.8%for air freshening products and 99.5% for cleaning/other products. Approximately 0.1% of the VOC’s that escape are lost as residual offgas from the crushed plates of cans during extended storage. The rest of the VOC losses occur during extended storage. The facility’s demonstrated performance meets and exceeds expected capture efficiency results. Furthermore, the steel recycling requirements of 7.5 grams or less of residual product per can was achieved as only 4 grams per can was measured.”

HANDLING OF CONTENTS – EVAC I and II:

The propellant and concentrate from cans are transferred to the primary receiver (pressure vessel). The propellant gas is lighter than the liquid and the liquid is usually lighter than the concentrate. Propellant can be drawn off as a gas using a pressure regulator to (1) be vented to atmosphere; (2) an open flare (thermal oxidizer) (3) to a furnace or boiler as supplemental fuel, or (4) reliquefied for concentrated storage or transport. When the pressure tank is lowered to 3 psi or less, the concentrate can be transferred to standard barrels for handling to an appropriate disposal site (heavy foams such as mousse, shaving cream, rug cleaner, etc., no longer foam.)

Hydrocarbons can be reliquefied into a 250 lb. test tank. When full, it can be moved to a cement plant, for instance, and off-loaded into bulk storage tanks.

If propellants can be released to atmosphere, low pressure tanks (barrels) can be substituted for high pressure tanks, and the propellant directed into the exhaust fan for positive mixing with adequate air, for safety, as it is released.

There is a secondary scavenger function to pick up any residual propellant left in or around the crushed cans before releasing the cans to atmospheric pressure. The tank is the surge so the vacuum can be performed in a minimum amount of time. A piston pump works continuously to hold a vacuum in the tank. The vacuum pump delivers this material into the main line to the pressure vessel.

EVAC III operates at atmospheric pressure and has a feeding system which allows for loading cans at floor level. Cans are crushed into solid metal bricks. Liquids are pumped to customer’s storage system and propellants positively controlled to atmosphere or to a disposal system.