P2: Dry Cleaning Equipment Changes

For new technologies that do not use perc, see Dry Cleaning Process Change.

For perc operations, replace old transfer machines with a new dry-to-dry machine.

• It eliminates transferring clothing from a wash unit to a drying unit.
• Less solvent loss through open doors.
• Reduces worker exposure. OSHA sets the regulated exposure limits for perc.
• The use of existing transfer machines will be prohibited as of July 28, 2008.

Use a reclaiming dryer.

• Reduces solvent losses.

Consider a cold-dry system, which uses lower temperatures.

• Minimizes solvent loss.
• Prolongs the life of the machine.

Use solvent leak detectors to monitor vapor losses.

• These will help you pinpoint where you are losing solvent, and money.

Use spin disc filters.

• Last longer than cartridge filters.

Use carbon adsorption units to recover exhausted solvent vapors from solvent storage tanks, distillation units, muck cookers, dryer condensers, and plant ventilators.

• Steam regenerates the solvent from the carbon bed. The steam-solvent vapor mixture condenses, and the solvent and water are separated. Such a system typically recovers more than 95% of the solvent from the air. The separated water may be reused; consider using some as a pre-spotter. Otherwise, it must be disposed of in an acceptable manner.
• Reduces air emissions and loss of perc.

Use a refrigeration/condensation unit.

• Condensers are equipped with a refrigeration unit to increase the condensation efficiency. Air containing solvent from the dry cleaning machine is fed into the unit and forced over a series of very cold baffles. The solvent/water vapor in the air condenses onto the cold metal of the baffle surface. The stripped air is returned to the dryer, while the condensed vapor drains to a water separator. Recovered solvent is returned to the storage tank for future use. The water may be reused; otherwise, it must be disposed of in an acceptable manner.
• Recovers solvent vapors; it may be over 90% efficient in solvent vapor recovery.
• Reduces air emissions.
• Refrigerator/condenser units come in many shapes and sizes. A machine sized for a 45-pound load will take up about one square yard of floor space. Some are designed to hang from the ceiling. If you have the room, however, a floor model is much easier to service. In a plant with more than one dry cleaning machine, multiple-machine refrigeration units can be used.

Some basics to consider when retrofitting existing dry-to-dry equipment with a refrigeration unit:

• Your plant must have a large enough electrical circuit and fusible disconnect to power the compressor fan.
• Use plastic piping to duct solvent-laden air from the exhaust of dry cleaning machine to the intake side of the refrigeration/condenser unit. Another pipe moves the treated air from the unit into the damper air intake on the cleaning machine. This closes loop on a vented machine. A small tube moves the reclaimed solvent from the refrigeration/condenser unit to a base tank in the cleaning machine.
• Retrofitting an existing dry-to-dry vented machine with a refrigerated condenser unit satisfies EPA air quality requirements, and will ultimately save money on lost solvent and hazardous waste shipping costs.
  

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