Composite Technology Pushes Cylinders to New Heights
The evolutionary spectrum of composite materials runs from aerospace to propane cylinders.
Today's advanced composite materials, which are composed of a wide range of substances, have been in development for decades. For pressure vessels, composite materials consist of a variety of materials, such as resins, glass fibres, and plastic materials, in different combinations.
The Western Hemisphere, and the U.S. in particular, are the largest untapped markets for these technologically advanced cylinders. At least two companies-Lite Cylinder Co. (Franklin. Tenn.) and its manufacturing partner Composite Scandinavia (Pitea. Sweden), and JNS Enterprises (Hilton Head, S.C.) and its partner Ragasco (Raufoss, Norway)-are racing to introduce composite cylinders into the region once they receive final approval from the Department of Transportation (DOT). The agency oversees the construction and use of cylinders through the Title 49 Code of Federal Regulations, which has not allowed the use of composites for the transport and storage of propane until recently.
A number of propane cylinder manufacturers began exploring the possibility of using the material in the 1980s. The initial reaction by some industry members was positive, said one long-time cylinder manufacturer, but the high cost of producing the containers ultimately reduced the number of companies exploring their development. Despite the possible economic hurdles, a small group of European manufacturers doggedly pursued the development of a working composite cylinder.
The cost wasn't the only stumbling block to introducing these cylinders. Codes and regulations would have to be changed. That process has been completed in Europe, Australia, and in parts of Asia. By the late 1990s, members of the U.S. industry were lobbying to change DOT rules governing the storage and transportation of propane. Working with the National Propane Gas Association (NPGA) and the Propane Education & Research Council (PERC), industry members have been pushing DOT to amend the rules to allow composite cylinders for propane storage and transportation. Proposals to change NFPA's code governing the use of propane and cabinet heaters is also in the negotiation stages.
One of the first companies to commercially produce cylinders specifically for liquefied petroleum gases was Composite Scandinavia in 1989. Kurt Berglund, chairman, began developing a revolutionary non-liner method for producing glass fibre composite vessels. He joined forces with Sweden's plastics industry, including the R&D departments of the firms that supplied resin and glass fibre, to further improve the technology that the company calls "Compolite CS."
The Composite Scandinavia cylinder is made of fibreglass-reinforced vinylester and weighs approximately 50% less than a conventional steel model. The design's hallmark feature is its translucency, which allows users to see how much fuel is inside. Designed with a two-piece casing that can be made in several colours and is stackable, the composite cylinders are also are corrosion-free. Composite Scandinavia uses air instead of water for pressure testing. The composite materials will remain rust-free and low-maintenance-soap and water is all that is needed to clean the outside of the cylinder.
European standards for composite cylinders require a 10-year retest period. The DOT exemption currently issued to the Lite Cylinder Co. requires a five-year retest period. The cylinders are expected to have an extended service life, and many composite proponents believe the exemption will be extended to a 10-year retest period consistent with the European standard.
The Scandinavian manufacturer has been making composite cylinders since 1995. The process requires no liner-two halves are made by winding fibreglass before being injected with plastic under high pressure in a hermetic process. After hardening, the two halves are de-moulded and then joined using a specially-developed method. After inspection and pressure testing, the coloured casing and valves are assembled.
Since the mid-1990s, Composite Scandinavia has sold more than 500,000 LPG cylinders, primarily to propane marketer customers in Europe, South Korea, and Australia. In the U.S., Lite Cylinder Co. was founded earlier this year. It will partner with Composite Scandinavia in introducing the cylinders, initially to the U.S., and later to Canada and the Caribbean.
Darrel Reifschneider, who ran Manchester Tank for several decades, is the force behind Lite Cylinder Co. Reifschneider practically has steel in his veins from growing up in the businesses his parents founded in the early 1950s. Also on board at Lite Cylinder Co. will be two other former Manchester Tank executives, Ben Sampson as president, and Shelley Moeller as executive vice president.
Reifschneider and his executives are excited about their new venture and product. Cylinders made of composite material are one of the most significant developments in the last 60 years. Because of their translucency, lower weight. and lower maintenance requirements, they are much more customer-friendly. Lite Cylinder's initial offering for the grill market will hold approximately 19 pounds.
Are these cylinders safe when threatened by fire? Testing and use in Europe has shown that composite cylinders won't necessarily BLEVE. Manufacturers believe, and testing has shown, that when subjected to heat and/or fire the cylinders permeability will increase. This will allow the gas to seep through the walls slowly instead of releasing large amounts of gas through the valve. As a fire around the cylinder intensifies, it will appear to be glowing with fire and not BLEVE. One cylinder manufacturer told BPN that the average temperature of most fires is not hot enough to melt the glass fibres.
Initially, the cylinders will be imported from Composite Scandinavia. Lite Cylinder Co. expects to begin manufacturing 10- and 20-lb cylinders in the U.S sometime next year. The primary market to be targeted first is the grill cylinder business-marketing to retailers and directly to customers. The cabinet heater market will also be targeted. Proposals to change codes and regulations covering the use of propane in cabinet heaters, and in other uses, are being discussed by NPGA, the National Fire Protection Association, and other code-making groups.
A proposal to PERC in 2001 by Larry Osgood of Consulting Solutions (Monument, Cob.) and PERC chairman Daryl McClendon to further investigate the composite materials potential put the idea on the table for discussion. To get DOT regulations changed, a Composite Propane Tank Working Group was organized with cylinder manufacturer and other industry members.
Battelle Memorial Institute (Columbus, Ohio) was hired in 2002 to lead the work, and Good Company Associates (Austin) was brought on to develop market strategy. Funded through a PERC grant, the group's initial target was to develop a "blanket request for exemption" from DOT by midsummer 2003. The exemption process is divided into three stages-an initial exemption for the product; then inspection and testing of the manufacturer and product; last, approval for importing. The process given to each firm that applies allows cylinders to be built to an approved specification and to be manufactured and sold by multiple entities. The testing and inspection process entails detailed examination and testing by DOT of working prototypes for each product seeking approval. In preparing for the process, the working group noted that for optimum success within a short time period, the industry needed to settle on a small number of products that could be quickly developed for submission.
Lite Cylinder and Ragasco have been given the initial exemption by DOT. A final exemption notice for each firm was expected before the end of the summer. The propane industry working group is continuing to push for a more simplified exemption process through the Research and Special Project Administration. Each manufacturer will have to renew its exemption every two years.
The composite cylinders' permeability was one of the issues of most concern to DOT, said a member of the working group. All materials are permeable to certain degree, and composite materials are slightly more permeable than steel. While propane molecules are very tiny, they still transmit through both materials, just at different rates. No odor fade problems have been found in the past decade of use in Europe.
When subjected to temperature extremes, the composite materials provide a bit more insulation, but the units will react similarly to steel or aluminum cylinders. The Battelle study found that composite materials won't transmit heat as quickly as steel.
Lite Cylinder's units have a slightly different design than many sold in Europe. The company's logo and a customer's logo and/or name, if requested, will be imprinted on the outside casing. Cylinders will be pre-purged, and UPC and serial numbers will be permanently bar-coded on the cylinders.
Manchester Tank (Brentwood, Tenn.) and Worthington Cylinder (Columbus, Ohio) will be the two companies Lite Cylinder and Ragasco have to face once their products are ready to market. And it's a big market, with more than 80 million cylinders currently in use. The average price for a steel cylinder is about $30 to $35, while Batelle's study found composite units will be closer to $50.
Both manufacturers have looked at composite materials and the manufacturing process. Dusty McClintock, Worthington's vice president of sales, told BPN that the company is very intrigued by the technology but that cost remains a factor.
While the cost of manufacturing and importing the composite cylinders remains higher than steel units, there is strong industry interest in them. PERC noted in its Propane Vision and Technology Roadmap that composite cylinders can provide significant advantages in durability, handling, weight. safety. and appearance. The council, in particular, believes the cylinders will fill niche opportunities, such as indoor cabinet heaters, that will increase sales for marketers.
The Battelle/Good study estimated that the longer service life of the composite units will save the industry upwards of $20 million a year. An additional $40 million can be saved on the recoating of the cylinders, a process that will no longer be necessary. There will also be additional savings from the reduction in employee and customer lifting-related injuries. Battelle also believes the composite cylinder market will pave the way for the future manufacture of larger composite ASME tanks that could be used in agriculture and over-the-road fuel applications. Currently, there are composite vehicle tanks in use in Europe.
In its final report, Battelle forecast that a significant short-term market entry opportunity may exist even if the initial retail market prices for standalone cylinders exceeds $50 due to ramped-up manufacturing and materials costs. They believe the majority of cylinders, though, will be acquired as a standard feature with the purchase of a barbecue.
As one of the largest potential customers for composite cylinder manufacturers, Billy Prim, CEO of Blue Rhino (Winston-Salem, N.C.), said these cylinders could have a very positive influence on the market. Surveys conducted by Blue Rhino indicate the cylinders could help expand the propane market into other areas such cabinet heaters. A member of the NPGA's cylinder exchange council, Prim summed up their potential, describing composite cylinders as one of the best new opportunities in recent years to grow the propane market.
Composite cylinders are formed by wrapping fibreglass fibres around a mandrel in multiple directions (second two photos) and saturating the fibres with resin to create each half of the cylinder. Next, appropriate holes are drilled In each half and the two halves are bonded together to create the cylinder. The completed cylinders are pressure-tested with air.
Composite Scandinavia was formed by Professor Kurt Berglund, and as the driving force behind the companies success where they now enjoy a market share in Scandinavia of more than 50% of all new cylinders sold.
This story was sent to NetComposites from the BPN Online Magazine.
Publication date: 15/10/2004
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