DRY FILTER PAINT BOOTH CONVERSION
 |
|
||||||||||||
| Overview: | The conversion of an existing water
curtain spray booth to a dry filter system for the removal of paint-based
particulates from spray booth air emissions will minimize the amount of
waste generated.
There are many types of dry filter systems, however, all operate on the same principle: particulate-laden air flowing towards the filter media is forced to change directions rapidly. The particulate, having more inertia than the surrounding air, impacts the filter media and is removed from the airflow. The scrubbed air is vented into the atmosphere. Before installing this technology, there are several system issues to be considered in the conversion of a paint spray booth. These include characteristics and applicability of dry filter systems, required fan size, dry filter surface area, paint booth duty cycles, and paint usage rates. An additional issue for consideration is the existence and variation of emission regulations in this country. Generally, the filter system must be chosen such that it meets all local, state and federal emission regulatory standards. There are many types of dry filter particulate emissions control systems (PECS) and filters available. There are four principal types of filters currently used: fiberglass cartridges, multi-layer honeycombed paper rolls or pads, accordion-pleated paper sheets, and clothe rolls or pads. Each type of filter has different characteristics for particulate capacity, removal efficiency, cost, and replacement time. Filter performance is characterized by three basic parameters: particulate capacity, resistance to airflow, and particulate removal efficiency. Paint characteristics, such as overspray particulate size distribution, should be compared to the filter’s performance parameters to obtain an effective match between components. Filter replacement is required when the filter becomes heavily laden with captured particulates, resulting in a reduction in removal efficiency and an increase in the pressure differential across the filter face. A filter system gaining prominence in the Air Force is the Styrobaffle Paint Arrestor. These filters are Styrofoam-like in composition, and are less expensive, last longer and are easier to dispose of than traditional fiberglass filters. When these filters are ready to be disposed, they may be simply dissolved in used paint gun cleaning solvent, which is then normally recycled. The waste stream generated in a dry filter paint booth is a spent filter laden with paint booth particulate emissions. No other media is contaminated during the collection of the particulate waste; hence the quantity of waste generated is minimized. For instance, when using lead or zinc chromate paints, the dry filter can eliminate approximately 50 to 90% of the hazardous waste that is generated by a water curtain spray paint booth. The removal and replacement of the spent filters is a simple procedure. The method for disposal of the spent filters will depend on the particular constituents of the paint used. Many facilities now segregate operations involving hazardous and non-hazardous painting into separate paint booths in order to expedite waste handling and disposal. The existing technology employs a water curtain to remove particulate emissions. The primary disadvantage of this technology is the generation of large quantities of wastewater and paint sludge. The wastewater typically requires off-site treatment and the paint sludge is frequently disposed as a hazardous waste. The Styrobaffle Paint Arrestors are highly recommended where applicable and are best used as the first stage of a two or three-layer air system. However, they do not meet NESHAP requirements and could not be used where the Aerospace NESHAP requirements are enforced. This does not apply to all Air Force bases. | |||||||||||||||||||||||||||
| Compliance Benefit: | Use of a dry filter paint booth
eliminates the wastewater and paint sludge (i.e., less hazardous waste is
generated) that are generated with a water curtain. This benefit helps
facilities meet the requirements of waste reduction under RCRA, 40 CFR
262, Appendix, and may also help facilities reduce their
generator status and reduce their regulatory burden under RCRA, 40 CFR
262 (i.e., recordkeeping, reporting, inspections, transportation,
accumulation time, emergency prevention and preparedness, emergency
response). In addition, the dry filter paint booth uses less water and
electricity, which meets the requirements in EO 12902. Conversion
to a dry filter system may also decrease a facility’s need for an
industrial wastewater discharge permit (local issue).
The compliance benefits listed here are only meant to be used as a general guideline and are not meant to be strictly interpreted. Actual compliance benefits will vary depending on the factors involved, e.g. the amount of workload involved. | |||||||||||||||||||||||||||
| Materials Compatibility: | Powder paint is typically not used in dry filter paint booths because this type of paint is usually recycled, which is not economical when using a dry filter paint booth. Facilities that must comply with the National Emissions Standards for Hazardous Air Pollutants (NESHAP) for Aerospace Manufacturing and Rework must use a two stage dry filter system. If the booth is new and the paint contains chromium or cadmium, then a three-stage dry filter system must be used. | |||||||||||||||||||||||||||
| Safety and Health: | The concerns with the dry
filter systems are with the variety of paints that are used and the
potential contaminant exposure. When using lead and zinc chromate paints,
inhalation of lead or zinc can irritate the respiratory tract and can be
poisonous. Some lead compounds are known to be carcinogenic. Solvent-based
paints can irritate the lungs and mucous membranes. Prolonged exposure can
affect respiration and the central nervous system. Proper personal
protective equipment (PPE) and filter handling procedures designed to
minimize the release of paint dust into the air should be used.
Consult your local industrial health specialist, your local health and safety personnel, and the appropriate MSDS prior to implementing this technology. | |||||||||||||||||||||||||||
| Benefits: |
| |||||||||||||||||||||||||||
| Disadvantages: |
| |||||||||||||||||||||||||||
| Economic Analysis: | Converting a water curtain
spray booth to a dry filter paint booth can be easily accomplished and can
be done in-house. The cost of conversion usually ranges from $200 to
$2,000, depending on the size and condition of the old water curtain spray
booth. Purchasing a new dry filter paint booth can cost between $2,000 and
$20,000. The conversion from a water curtain spray booth to a dry filter
paint booth can save several thousand dollars in operating and maintenance
costs per year.
Assumptions (from Columbus Industries, Inc.):
Annual Operating Cost Comparison for Dry Filter Paint Booth Conversion and Water Curtain Spray Booth
Economic Analysis Summary Annual Savings for Dry Filter System:
$13,840 Click Here to view an Active Spreadsheet for this Economic Analysis and Enter Your Own Values. To return from the Active Spreadsheet, click the reverse arrow in the Tool Bar. | |||||||||||||||||||||||||||
| Approving Authority: | Approval is controlled locally
and should be implemented only after engineering approval has been
granted. Major claimant approval is not required. Authority for conversion
is local at each base.
|
| NSN/MSDS: |
|
| Points of Contact: | Air Force: CMSgt. Owen Jett Air Force Corrosion Prevention and Control Office AFRL/MLS-OLR(NCI) 325 Richard Ray Boulevard Robins AFB, GA 31098-1640 Phone: (478) 926-3284 DSN: 468-3284 FAX: (478) 926-6619
|
| Navy: Mr. Lynn Cahoon Naval Aviation Depot A Street, Building 4032 Cherry Point, NC 28533 Phone: (252) 464-8141 DSN: 451-8141 Mr. Bob Fredrickson |
| Vendors: | This is not meant to be a
complete list, as there are other manufacturers of this type of
equipment.
Columbus Industries, Inc. |
| Research Products
Corp. P.O. Box 1467 Madison, WI 53701-1467 Phone: (608) 257-8801 | |
| Chemco Manufacturing
Company, Inc. 3225 Commercial Ave. Northbrook, IL 60062-1920 Phone: (800) 323-0431 | |
| Fluid Air Products
(Government Distributor) 12834 Gravois Road St. Louis, MO 63127 Phone: (314) 729-7000 or (800) 365-7565 FAX: (314) 729-7099 Contact: Bob Hunt Email: info@fluidair.com |
| Sources: | Columbus
Industries, Ashville, OH
|
[Back]