Chemicals Americas, Inc.
February 28, 2011
Alexander Ryan-Bond
Environmental Associate
Ozone Transport Commission
444 North Capitol St., NW, Suite 638
Washington, DC 20001
Subject: OTC Model Rule for Solvent Degreasing 2011
Dear Mr. Ryan-Bond:
AGC Co., Ltd, is an global manufacturer of Glass, Chemicals, Optics and Electronics with yearly sales of approximately 11 Billion US, and 50,000 employees. We appreciate the opportunity to comment on your proposed rule making.
Over the past two decades, Federal, State and Local agencies have implemented different steps towards controlling fugitive emissions. The intended net result was to enact functional regulations that may be challenging, but not impossible to meet. It appears that the OTC has attempted to compile some of these regulations into a single document. We believe that there are some sound and logical steps within this proposal. However, we also feel that there is redundancy and overlap, which may preclude viable solutions. We have a few overall comments that we feel need to be documented. First, we would like to provide some general background on vapor degreasers, and the solvents used in them.
Vapor Degreasers:
The federal NESHAP standards were enacted about 15 years ago. They set a good foundation for an efficient, low emission vapor degreaser. The NESHAP offers options so that the user can select a combination that works well for his particular needs. What has been learned is that requiring a degreaser to have a minimum of 100% freeboard, a second set of near zero condensate coils ( freeboard chillers), and a working cover are the basics for an efficient machine. Automated hoists have benefits such as minimizing drag-out an ease on worker related injuries. However, if the output is small, the hoist can actually drag out more solvent then it is trying to save. Further, if it is engineered inside the coils, the mast acts as a barrier to the coils allowing solvent to wick out of the machine. Other technologies including super-heat and lip-exhaust systems are old technologies that may have been good in theory, but actually create a much greater solvent loss then if they had not been employed at all.
Degreaser size: There are regulations in California restricting a degreaser to 1 sq. ft. of opening or less. When the machine design starts getting this small (or smaller), the balance between heat load, work load, and refrigeration mayget out of balance. A machine is designed with the necessary heat that will raise the solvent, and the parts to be cleaned to a certain temperature. The refrigeration load is calculated to offset that given heat output, so that the vapors can be kept in the machine. While a small machine may have a 100% freeboard, if the distance between the liquid level and the bottom of the condenser coils is only a few inches, the cavitations of the boiling sump may push fugitive emissions above the primary coils, reducing the efficiency of the machine. Machines with an approx 2 sq ft opening (1 sq ft per sump) can be just as efficient, or better then a smaller designed machine. Again, we believe the desired result of the regulation is to control the emissions and not the process.
Airless/ Air tight machines:
There are only a few companies that make a good vacuum machine, but they are available. The restrictions of this technology are the price of the machine; the small cavity for parts to be cleaned, the long process times, and the effect that the vacuum can have on the solvent. If the solvent is not stable (single carbon bonds), the vacuum process can actually pull apart the solvent, yielding unexpected consequences.
Large Machines:
Most of the legacy large machines have been replaced with newer, smaller more efficient machines. Large machines still exist, but now are primarily found in Tier 1 companies manufacturing components for Aerospace, Military, Medical and the Aircraft industry. Again, a good set of secondary refrigerated condensate coils, and an automated hoist are your best control technologies here.
Nonflammable, fully evaporating Solvents:
Historically, vapor degreasing has been done with non-flammable halogenated solvents. The base materials may be blended with alcohols or hydrocarbons to clean a particular contaminant. If the company wants to remove and organic contaminant, it is most efficiently done with an organic solvent. The industry uses the phrase “like dissolves like”.
CFCs were phased out of commerce in the 1990s, with only the US government still holding inventory for military or NASA applications. HCFCs will be phased out of interstate commerce on January 1, 2015. Trichloroethylene, Perchloroethylene and Methylene Chloride are being passed over by many large corporations due to these solvents being probable and possible carcinogen effects. Normal Propyl Bromide has been found to cause cancer in laboratory animals and is scheduled for tighter regulation by the US EPA.
What are left of the nonflammable solvents are Hydrofluoroethers, and Hydrofluorocarbons. In order for these solvents to be universally effective, they must be blended with other solvents, which are VOCs.
Low vapor pressure fluids/ cleaning oils
Under the right criteria, low vapor pressure fluids or oil based cleaners can fulfill a need. Care has to be taken as some low pressure solvents have very low AELs, (less than 10). Cleaning oils may remove the gross contaminant, but leave behind a hydrocarbon residue. Users must decide if this technology works for them. This is more of a niche solution, then a mainstream alternative.
Flammable Solvents: Common hydrocarbons and Volatile Methyl Siloxanes can be used safely in explosion proof machines. These machines are expensive (approximately $250,000) and need to be kept in isolated rooms. They tend to be enclosed
2-sump degreasers that designed for small to medium obtained. These solvents are 100% VOCs.
Comments:
There is no panacea for production cleaning. Solvents, hydrocarbons, Water, and Super Critical CO2 each have their attributes and limitations. Industry must be able to choose which process is most viable for their application.
We support the efficient use of any fluid, but believe that there is a point of diminishing returns in regards to conservation, monitoring, and control techniques. We suggest discretion by the OTC when deciding the extent of the regulation.
We encourage the OTC to consider requiring vapor degreasers be built to NESHAP standards, regardless of the solvent to be used. This will ensure efficiency. Machine size is dictated by product work load and through-put. We feel that the NESHAP guidelines adequately address the variations that the market requires.
Additional guidelines regarding MACT or BACT could also be considered or exempted depending on application.
We believe that the OTC should follow historical models in granted use exemptions for applications in electronics cleaning and defluxing, Aerospace and Aircraft production, and for Military and NASA components.
Finally, guidelines by VOC, MIR, or vapor pressure may also be deemed necessary. VOC restrictions are the most common, yet MIR standards are gaining acceptance. Vapor pressure regulations are less prominent, and can be confusing. We offer to work with the OTC to find a suitable common ground on VOC or MIR guidelines that would be manageable with the regulations of today, and the proposed (global warming) regulations of tomorrow.
We thank the OTC for allowing us to comment, and look forward to continuing this dialogue.
Warmest Regards;
David A. Ferguson
Business Manager
AGC Chemicals Americas, Inc.
Exton, PA 19341
610-423-8113