Clean bill of health for HFCs, and DuPont's pushing them.
Fear not! Hydrofluorocarbons won't damage the ozone layer, according to a new study by the US National Oceanic and Atmospheric Administration (NOAA). Maybe the world's largest chemical supplier had advance word, because it's now doing a full-court press to promote a line of HFC-based replacement refrigerants.
E.I. duPont de Nemours & Co., Wilmington, Delaware, USA, is currently marketing its alternative refrigerants under the Suva |R~ brand. Most important for the commercial and industrial market is Suva 134a (Suva Cold MP), a replacement CFC-12 -- which has long been the dominant chlorofluorocarbon used by refrigerated warehouses and for freezer cases in supermarkets.
DuPont hosted a press conference in New Orleans recently to promote the whole Suva line, but Suva 134a actually got less attention than two other alternative refrigerants: Suva AC9000, which had just been recognized by Underwriters Laboratories as a "practically nonflammable" replacement for HCFC-22 in air conditioners and heat pumps; and the newly-patented Suva HP62, which can replace R-502 in household air conditioners and refrigerators.
A ternary blend of HFC-32, HFC-125 and HFC-134a, Suva AC9000 is said to have a zero ozone depletion potential (ODP), compared to 0.555 for HCFC-22 and 1.0 for CFC-11. Its global warming potential (GWP) is 1600, the same as for HCFC-22. The new blend has also tested very low for toxicity, DuPont said. Like the refrigerants it replaces, it is non-flammable. Suva HP62 is a blend of HFC-125, HFC-143a and HFC-134a, also non-flammable and with a zero ODP.
The NOAA study on HFCs was published in the January 1994 issue of Science, and appeared to refute claims nearly a year earlier by a group of scientists at the University of Dublin in Ireland that HFCs break down into molecules of one carbon and three fluorine atoms that might act as catalysts in destroying ozone. NOAA's study simulated conditions in the stratosphere using a pulsed laser and a chemical reactor. Oddly enough, a DuPont spokesman was quoted at the time as saying HFCs would play only a small role in CFC replacement, and that ammonia or new technologies involving gases like carbon dioxide and sulfur dioxide would be the wave of the future.
Pilgrims for HFC-134a
Several retailers and at least one restaurant operation in the USA are moving to convert their refrigeration systems. Market Basket, a 52-store supermarket chain based in Tewksbury, Massachusetts, has already switched two of its stores from CFC-12 to HFC-134a. The chain plans to stop buying CFCs this year, and eliminate their use entirely by the turn of the century. Other chains involved in conversions include Jitney Jungle, Furr's, Wawa (convenience stores) and Hick'ry Pit Restaurants.
The first Market Basket converted to HFC-134a was in Wilmington, Mass., and the second in nearby Woburn. But even before the conversions, John Patinskas, manager of refrigeration for the chain, had ordered a conservation program to reduce consumption of CFCs, which he knew would soon be hard to get. Two mechanics were assigned full time to detect and repair refrigerant leaks, and CFC recovery units were purchased for every truck in the department.
"With the price of CFC refrigerant what it is, the work that the leak detection crew does pays for itself," Patinskas remarked. As for the recovery units, he added, "Since some of our stores are pretty far from headquarters, driving to and from our maintenance shop would have wasted valuable time and money. Buying a recovery unit for every truck just made good sense."
Leak detectors have been installed as part of refrigeration monitoring and control systems, and improved maintenance has paid off in the virtual elimination of leaks and therefore of the need to buy expensive refrigerant. "The CFC issue is really making supermarkets manage in a whole new way, and that's not necessarily bad," Patinskas noted. But conservation is only the first step; conversion is the ultimate goal.
Market Basket chose two of its older stores for the first conversions to HFC-134a. "We planned to reduce CFC-12 purchases to zero and get experience with HFC-134a in one stroke," he explained. At the Wilmington store, medium temperature equipment was the first to be converted. First all the mineral oil lubricant used with CFC-12 was flushed from the system, using polyol ester lubricants compatible with HFC-134a. The systems were then charged with HFC-134a.
The whole job was done in a night, so the store didn't lose any business. But there turned out to be bugs in the conversion process. Most important, it developed, gaskets that were tight enough for CFC-12 leaked HFC-134a like a sieve. All valves using those gaskets had to be overhauled. It also developed that polyol ester lubricants were great at cleaning up pipe scale, sludge and other contaminants; but that meant filters were needed to catch all the crud the new lubricants remove.
Hitches Are Educational
"It would have been nice for the test conversions to have proceeded without a hitch, but our whole purpose in conducting these tests was to find out what kinds of problems would occur," remarked Patinskas. "It's much better for these types of unforseeable events to occur in a test installation only once, rather than chainwide." The experience at Wilmington stood Market Basket in good stead when it undertook the second conversion to HFC-134a at Woburn. This time, Patinskas sought technical advice from DuPont, Allied Signal, Hussman, Phoenix, Elf Atochem and other industry sources.
For the time being, Patinskas leans toward using HCFC-22 in new installations of medium-temperature equipment, in combination with polyol esters, so that when it does come time to switch to HFC-134a, the chain won't have to replace the lubricants all over again. The test conversions to HFC-134a suggest that the average conversion cost will be $31,000 a store -- $24,000 for 2,300 pounds of the new refrigerant, $2,100 for 60 gallons of lubricants, $600 for new gaskets and filters, and the rest for labor.
In Forest, Mississippi, Jitney Jungle built a new supermarket with a refrigeration system designed to use DuPont's Suva HP80 (a blend of HCFC-22, HFC-125 and HC-290) as a replacement for R-502. James Riley, vice president of engineering for the Jackson-based chain, found the blend to be more energy efficient than straight HCFC-22. Furr's, based in Albuquerque, New Mexico, is using another blend, Suva M39 (HCFC-22. HFC 152a and HCFC-124), but only in meat and dairy cases, as a replacement for CFC-12. A similar blend, Suva MP66, is being used by Hick'ry Pit to replace CFC-12 and HP 80 to replace R-502 in low-temperature applications. All blends using HCFCs, of course, will have to be phased out ten years from now.
Ozone Depletion Stabilized?
Ozone depletion appears to have stabilized, evidently due to the decline in production of CFC-11 and CFC-12, according to a NOAA study reported in the Washington Post. But that doesn't mean the danger is past: there is still a big hole in the ozone layer that won't close until levels of CFCs in the stratosphere decline sufficiently to stop reacting with ozone. One recent report suggested that increased ultraviolet radiation that reaches the Earth's surface is responsible for a catastrophic drop in the frog population -- if the depletion of ozone is killing frogs, it could be having other effects.
Under the current version of the Montreal Protocol (which has been stiffened several times already, and might be again), CFC production and consumption must be reduced by 75% this year and next, and phased out entirely by Jan. 1, 1996. HCFC consumption is to be frozen in 1996, then cut 35% by 2004, 65% by 2010, 90% by 2015, 99.5% by 2020, and eliminated entirely by 2030. Also being eliminated are three other sources of damage to the ozone: hydrobrominated fluorocarbons, methyl chloroform and carbon tetrachloride (They've all got to go by 1996, just like CFCs). Methyl bromide is on the list too, but the phaseout schedule hasn't been established yet.
'S No Foolin', Says TranSnow, C|O.sub.2~ can Replace Refrigeration
Do you really need bulky compressors and condensers for refrigerated containers and trailers? No, says TranSnow C|O.sub.2~, Inc., of Yonkers, N.Y. and Jacksonville, Fla., USA -- which offers a spray header system for dry ice as an alternative.
The C|O.sub.2~ unit cuts costs by a third, reduces container weight, and avoids the risks of mechanical breakdown and food spoilage, according to Zachary Schulman, president of TranSnow. Because traditional Chlorofluorocarbon refrigerants -- R-12, R-22 and R-502 -- will be phased out by 1996, the frozen food industry will be forced to find an alternative.
"In more than 150 export shipments, we have proven the concept of using C|O.sub.2~ as a passive refrigeration system," Schulman declared. "We are now negotiating with a number of frozen food processors who want to buy our system for domestic and international transportation." Since about a year ago TranSnow has been using 50 converted 40-foot containers in shipments to and from Puerto Rico, between California and Hawaii and New Jersey and Bermuda, and within the continental United States. Shipments have included ice cream, frozen orange juice pulp and concentrate, pork and beef products, and french fries.
Dry ice is nothing new, but TranSnow has a patent on the configuration of stainless steel tubing in its spray header, which is said to be 50% more efficient than traditional systems at converting liquid C|O.sub.2~ to snow. The snow fills the container evenly to surround the cargo, and keeps the cargo below zero degrees F for up to 14 days. The header costs only $2,500 to $3,900, vs. $12,000 to $20,000 for new mechanical refrigeration units, and weighs only 100 pounds, vs. 2,500 pounds.
Allied Signals End to CFCs
AlliedSignal, Inc., will close down it chlorofluorocarbon production facility at Danville, Illinois, USA, as of Aug. 31, the company announced recently.
"Demand for these products has been greatly reduced as the result of the accelerated global phaseout of CFCs," noted Paul Norris, president of the company's Chemicals and Catalysts unit. Allied hasn't been able to find any other use for the plant, so manufacturing at Danville is being shut down. A small transportation terminal will be retained. The company is "investing" in alternative fluorocarbon refrigerants, Norris said.
Keep Methyl Bromide off Phaseout List, AFFI Urges Environmental Protection Agency
The American Frozen Food Institute (AFFI) is calling on the Environmental Protection Agency (EPA) to work with industry to develop safe and suitable alternatives to methyl bromide, rather than add the chlorofluorocarbon to the list of Class 1 ozone depleting substances--a move that would accelerate its phaseout.
"AFFI objects to the Agency's action because there still exists a significant lack of scientific agreement concerning the effect of methyl bromide on the ozone layer. Further, we believe this proposal potentially could affect domestic production agriculture if a safe alternative is not found," said AFFI President Steven C. Anderson in a paper filed with the Air and Radiation Division of EPA.
AFFI first commented on the phaseout of methyl bromide last May when the EPA was contemplating classifying the substance as an ozone depleter. The McLean, Virginia-based organization holds that the Agency should not take final action on the use of this important agricultural chemical--for which there currently are no safe alternatives--until an accurate scientific consensus on its true ozone depletion potential (ODP) is developed.
"Agency action at this time sends an inappropriate message to the scientific community as a whole, emphasizing that EPA in the future will react with 'publicly acceptable' expedient solutions to an environmental issue rather than have its decision based on a preponderance of sound science," said Anderson. He added that while safe alternatives exist for methyl bromide when used as a soil fumigant, so far no safe alternative has been found for its use as an agricultural fumigant in international trade--approximately 15% of its use.
According to AFFI, the implications for domestic production agriculture could be disastrous is a safe alternative for fumigating agricultural products imported into the USA is not found before the phaseout date.
"AFFI believed that EPA should become a part of the solution to the problem by working with USDA and industry to effectuate safe and suitable alternatives to methyl bromide. If the Agency succumbs to the pressure of environmental groups and a viable alternative is not found by the proposed phaseout date, agriculture, industry and ultimately the consumer will suffer," concluded Anderson.
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|Title Annotation:||includes related article; hydrofluorocarbons; E.I. du Pont de Nemours and Company Inc.|
|Publication:||Quick Frozen Foods International|
|Date:||Apr 1, 1994|
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