United States Environmental Protection Agency Research and Development Air and Energy Engineering Research Laboratory Research Triangle Park NC 27711 EPA/600/S2-90/057 Mar. 1992 EPA Project Summary Solvent Emission Reduction Study at Newark AFB, Ohio Jacqueline Ayer and C.D. Wolbach The objective of this effort was to collect baseline Freon emissions data, and subsequently recommend poten- tial emission control alternatives to mini- mize Freon emissions that result from routine maintenance and repair opera- tions conducted at Newark AFB, Ohio. This Project Summary was devel- oped by EPA's Air and Energy Engi- neering Research Laboratory, Research Triangle Park, NC, to announce key find- ings of the research project that is fully documented in a separate report of the same title (see Project Report ordering information at back). Introduction Newark AFB, Ohio, uses a number of solvents to clean and maintain electronic guidance devices. The solvent most often used in this application is 1,1,2-trichloro- 1,2,2-trif luoroethane, commonly known by the DuPonf Company trademark Freon 113™ (hereafter referred to as Freon}. New- ark AFB purchases large quantities of Freon (nearly 600,000 Ib annually), and in previ- ous years, lost nearly all of. it (555,000 Ib) as unrecovered Freon vapor.* Freon is * This quantity was derived in an earlier solvent inven- tory study performed to identify significant Freon emis- sion sources at Newark AFB. This study took into consideration the quantity of Freon purchased in the 1-year period studied, the change in the quantity of Freon stored onsite, and the quantity shipped offsite as a hazardous waste and sold to a solvent reclama- tion facility. The quantity of Freon lost due to evapora- tion (555,000 Ib [252,272 kg]) was only slightly less than the quantity purchased (596,000 Ib [270,909 kg]). one of a general class of chemicals known as chlorofluorocarbons (CFCs). Scientific evidence strongly suggests that CFG emis- sions are responsible for the depletion of the protective ozone layer surrounding Earth's atmosphere. For this reason, the U.S. Air Force must reduce and eventually eliminate CFC emissions from Air Force facilities. Several steps have been taken to re- duce the quantity of Freon emitted, from the more than 100 emission point sources at Newark AFB. For example, solvent va- pors emitted from more than half of the point sources at the facility are recovered with limited success by the use of two carbon adsorption (CA) systems. The per- formance of the recovery system in the past has been marginal at best, primarily due to an inadequate regeneration sched- ule. In addition to the CA systems, continu- ously operated distillation equipment is used to purify recovered liquid Freon for reuse. However, military specifications re- quire that most processes use only ultrapure solvent, so only Freon that is not significantly contaminated may be recycled. The remainder is sold to an offsite waste handling .facility. Scope To develop methods of reducing Freon emissions from the cleaning and mainte- nance activities at Newark AFB, baseline emissions testing at key sites was per- formed. The data collected were evaluated to identify primary emission sources, and ventilation system inefficiencies. The re- sults of this evaluation were used to de- Printedon Recycled Paper ------- velop several Freon emission reduction strategies. Approach This project was conducted in two steps. Step 1 involved a source identification study and a Freon emissions survey. Such engi- neering parameters as temperature, pres- sure, flow rates, and Freon concentrations were measured. This information was re- quired to accurately determine the Freon emissions profile of Newark AFB, as well as to facilitate the identification of various emission reduction strategies. Step 2 con- sisted of reducing the data collected in Step 1 and developing and evaluating a number of Freon emission control strate- gies. Test Description Three principal measurements were performed during this test series: (1) mea- surement of airflow rates through exhaust ducts, (2) measurement of the linear flow rate at the front faces and access ports of process booths connected to the CA sys- tems, and (3) measurement to determine Freon concentration variations in the duct over an extended period of time. At two test sites (CA 3 and 4), a fourth measure- ment was performed to determine the 1,11,1 - trichloroethane (TCA) concentration variations. TCA is occasionally used in the process booths connected to the CA sys- tems. Results The emission test results obtained were in good agreement with results obtained from the Freon emission inventory study performed a month prior to testing. Thus, the confidence level in the data collected is high. Several Freon emission reduction strategies were identified based on these results which, if implemented, will result in a Freon emission reduction of more than 60%. Conclusions From the. data collected in this test effort and the engineering evaluation re- sults, the following conclusions can be drawn: The quantity of Freon emitted from the Peacekeeper, Refurbishing, and Clean Room 12 areas total more than 54,432 kg (120,000 Ib) per year; thus emissions from these areas should be targeted for major reduction. Emission sources not vented from process areas should be placed in hoods vented to a solvent vapor re- covery system. Current CA system regeneration schedules are inadequate. • Test results are in general agree- ment with those obtained from the Newark solvent chemical inventory survey performed prior to testing. Implementing the recommendations made in this report should result in an emissions reduction of more than 113,400 kg (250,000 Ib) annually. Recommendations Recommendations made are of two types: those that can be adopted almost immediately and those that will take some time to implement. These short- and me- dium-term recommendations are presented separately. The medium-term recommen- dations are: Significant emissions from the Peace- keeper area should.be eliminated by connecting the source exhaust ducts from the Peacekeeper area to the CA 3/4 network. Under current operations, CA 4 is significantly underutilized compared to CA 3, which is operating at near maximum capacity. Newark AFB should either1 connect the Peace- keeper area exhaust ducts to CA 4, or offload most of the CA 3 sources to CA 4, and connect the Peace- keeper exhaust ducts to CA 3. • Some flow balancing will be required after the sources are integrated to ensure that sufficient ventilation air passes through each source. A separate solvent vapor recovery system should be installed to control emissions from the Refurbishing and Clean Room 12 areas. The emission sources that are cur- rently uncontrolled (i.e., degreasers and ultrasonic cleaners), should be vented to a vapor recovery system. However, the cumulative contribution from these sources could have a sig- nificant impact on the recovery sys- tem operation. Thus, after they are vented, the Freon emissions from these sources should be quantified to assess their potential impact on vapor recovery system operations. A means of determining Freon evapo- ration rates in the significant emis- sion source areas (i.e., Peacekeeper, Refurbishing/Clean Room 12, Clean Room 3) should be installed. In this way, the impacts of changes in oper- ating areas on CA bed performance can be determined. The short-term recommendations are: Feedback control loops should be installed at the exits of both CA sys- tems to eliminate the emission of Freon vapor into the environment due to CA bed breakthrough. CA 3 and 4 should be converted from split-flow to single-bed opera- tion. Until feedback control loops are in- stalled in the CA bed effluents, new regeneration schedules for CA 3 and 4 should be adopted. Freon emissions from CA 4 due to the intermittent duty cycle of the point sources vented in CA 4 should be significantly decreased. The most cost-effective means of controlling these emissions is to turn off the 10- hp (7.5 kW) exhaust fan upstream of the bed during process downtime (i.e., weekends, and second and third shifts). This will reduce the possibility of solvent migration through the bed and subsequent breakthrough. •&U.S. GOVERNMENT PRINTING OFFICE: 1992 - 648-080/4017S ------- ------- J. Ayerand C.D. Wolbach are with Acurex Corp., Mountain View, CA 94039., Charles H. Darvin is the EPA Project Officer, (see below). The complete report, entitled "Solvent Emission Reduction Study at Newark AFB, Ohio," (Order No. ADA 242-091/AS; Cost: $26.00, subject to change) will be available only from: National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 Telephone: 703-487-4650 , The EPA Project Officer can be contacted at: Air and Energy Engineering Research Laboratory U.S. Environmental Protection Agency Research Triangle Park NC 27711 United States Environmental Protection Agency Center for Environmental Research Information Cincinnati, OH 45268 BULK RATE POSTAGE & FEES PAID EPA PERMIT NO. G-3S Official Business Penalty for Private Use $300 EPA/600/S2-90/057 ------- |