The Queen Mary 2 is the Titanic of modern-day cruise ships. It cost an estimated $800 million to construct and can accommodate 2,620 passengers with a crew of 1,253. It can generate 157,000 horsepower. It weighs 151,400 tons and stands 236 feet high. And, at a length of 1,132 feet (just 117 feet shorter than the Empire State Building), the QM2 holds the title as the largest passenger vessel ever built and is a tremendous example of engineering prowess.
Now, you ask, what does the Queen Mary 2 have to do with fluid handling? Well, the Premium do Brasil and its sister ship, the Carlos Fischer, are the equivalent of the QM2 in the aseptic processing and packaging world. Built for Citrosuco (www.citrosuco.com.br), a company that processes not-from-concentrate (NFC) and from concentrate (FC) orange juice and apple juice concentrate, the Premium do Brasil and Carlos Fischer are at the technological forefront of bulk aseptic storage and transport. The ships, which are the length of two football fields, are each capable of holding 7.6 million gallons of juice.
History & Applications
The process behind bulk aseptic storage was patented by Purdue University in 1972. Philip E. Nelson, Ph.D., Scholle Chair of Purdue’s Department of Food Science (www.foodsci.purdue.edu), led much of the research that resulted in the initial concepts for bulk aseptic storage, which essentially allows raw product to be sterilized, cooled, and stored in large tanks. The primary advantage of bulk aseptic storage is that it enables raw product to be partially processed, stored, and/or shipped prior to final processing. Further, it supports incremental product withdraw without compromising sterility. As a result, Citrosuco can move product from Brazil to several processing or distribution facilities in the United States, Europe, and/or Asia in a single trip without the risk of microbial contamination.
According to Dr. Nelson, who served as a consultant on the development of Citrosuco’s aseptic ships, the most successful application of bulk aseptic storage to date has been for storing and transporting not-from-concentrate orange juice. However, he sees a number of other areas where the technology might be a good fit. For example, he says wine and even water could benefit from bulk aseptic storage and transport. Water, Dr. Nelson says, could be an interesting application, as bulk aseptic tanks could be used to transport large quantities of drinking water to remote, drought-stricken locations.
"To be a candidate for bulk aseptic storage the product has to be [used] in large quantities, and it has to be pumpable," says Dr. Nelson. Besides orange juice, he says grape juice and tomato paste have generated a significant amount of uptake for bulk aseptic technology. Although, he says recent advancements in bag-in-box technology — namely the rise of the 300-gallon bag-in-box container — have usurped the tomato paste market. In addition, Dr. Nelson says there are certain products for which bulk aseptic storage is not a good fit. For example, he says milk is not a candidate because it has a high pH (above 4.6) and can be susceptible to sporeformers.
Setting Sail
The Premium do Brasil and Carlos Fischer are second-generation technology. Initially, Aleuropa, Citrosuco’s sister company, commissioned Kleven Florø (www.klevenmaritime.no), a Norwegian-based maritime engineering firm, to outfit two existing ships with ultra-clean systems — a precursor to bulk aseptic technology. These ships, the Ouro do Brasil and the Sol do Brasil, each with 3.2 million gallon capacities, tested the viability of bulk aseptic storage and transport by water, and both are still in service today. After successfully deploying these ships, Aleuropa upped the ante, hiring Kleven Florø to build two more ships with twice the capacity of their predecessors.
The ships are used to transport juice from Citrosuco’s orange tree estates in Brazil to the United States, Belgium, Japan, and Korea. The Carlos Fischer and Premium do Brasil have four refrigerated holds, each of which has four, free-standing, bulk aseptic storage tanks. Some of the tanks are used for not-from-concentrate juice; some are used for frozen concentrate juice.
The Premium do Brasil and Carlos Fischer are the world’s largest vessels for transporting fruit juice. Nearly exact replicas of each other, the two ships are just over 676 feet long, they have a maximum deadweight of more than 46,000 tons, and they boast of a gross carrying capacity in excess of 36,300 tons. And despite such tremendous mass, the ships are capable of speeds over 20 knots.
The ships’ living quarters can comfortably accommodate 30 people. The master and chief engineer have suites of rooms on the third cabin deck, and the Owner’s Suite covers about 150 square feet, not including its three guest cabins. Single cabins are available for all officers and crew, each of which includes attached toilet and shower facilities. The ships are also outfitted with a swimming pool and fitness center. Floating decks in the bridge and directly above the ships’ engine are designed to cut down on excess noise and vibration.
Currently, the Premium do Brasil is captained by Bernd Springer. One of several captains employed by Aleuropa, Springer has been trained and is qualified to operate all of the Premium’s systems. Citrosuco has a formal education program for the captains of its aseptic ships. Part of this training regimen requires them to serve as lower-ranked officers so they can learn the nuances of operating a specialized aseptic ship.
Specifications
The technology behind Citrosuco’s aseptic ships is complex and involved. The wetted surfaces of the ships’ pumping and piping systems must be kept in compliance with the latest aseptic standards. As such, all surfaces that come in contact with orange juice are made of stainless steel. Special diaphragm and sealing solutions are incorporated into valves to ensure sterility. Larger valves, which cannot be sealed with diaphragms, include valve rod seals fitted with spirit reservoirs to support volume changes and wiping action on exposed portions of the valve. Flanges are designed to the German DIN 11864 standard to eliminate cavities where bacteria could build up. The ships’ cargo tanks are cylindrical units with vertical axes. The bottom of each tank slopes to a definite lower point; the top is slightly conical. The piping is connected to the lowest point to enable the tanks to be fully drained. The cargo pumps are fitted at cargo hold bottom level between the cargo tanks. Frequency-controlled, electrically driven centrifugal pumps handle the fresh juice, while a wider piping system and a series of custom frequency-controlled, electrically driven positive displacement pumps support the concentrated juice process. Radar level gauges determine how much product is in the tanks, nitrogen pipes deliver nitrogen to fill the headspace in the tanks, and temperature sensors are used to monitor the cooling system.
A protective atmosphere of nitrogen is used in all tanks and piping systems to prevent juice oxidization. The ships have an on-board inventory of nitrogen to provide a buffer for maintaining the appropriate levels in the tanks and piping while at sea. When juice is discharged at port, nitrogen is pumped into the tanks from a shore-based source.
Propeller-type tank agitators ensure circulation of tank contents when natural juice is being carried. Customized tank cleaning systems ensure aseptic conditions during cleaning and disinfecting of the large tanks. Fresh water for tank cleaning and rinsing is drawn from large tanks near the engine room. Empty tanks are filled with nitrogen after cleaning to ensure sterility. Three electrically driven refrigerant compressors are installed in the deckhouse. Brine from the evaporator room circulates through heat exchangers in each hold where large fans lead air to all parts of the insulated holds through strategically placed ductwork. Juice is loaded at the required temperature, and the refrigerating system has the capacity to maintain this temperature no matter what ambient conditions are encountered during the voyage. The capability of the equipment is –10 C to 20 C. The ships are also outfitted with redundant refrigeration and power generation equipment, which is designed to protect the cargo in the event of a mechanical failure.
Operation & Support
The cargo systems of the Premium do Brasil and Carlos Fischer are maintained with clean-in-place and sterilize-in-place processes. "Clean-in-place and sterilize-in-place is something the average seaman doesn’t know about," says Doug Nicol, vice president of Citrosuco North America. As such, he says the crew on Citrosuco’s aseptic ships must undergo training to develop a working knowledge of aseptic technology.
"[The ships have] very specialized equipment that has to be properly operated and maintained to ensure the product remains sterile," says Nicol. "Any breakdown in procedure or equipment can result in contamination of the juice product."
The ships carry concentrated juice at a constant temperature of 14 F and fresh juice at 32.9 F. Three of the ships’ holds can support frozen or chilled cargo; one is reserved exclusively for fresh juice.
According to Dr. Nelson, one of the key evolutions of bulk aseptic storage from the time that he developed the initial concept is the level of automation now involved in the process. "Automation has really helped, because we can take away a lot of the human error," says Dr. Nelson. Specifically, he says electronically controlled processes for filling and withdrawing from the tanks has helped better ensure the sterility of the end product. Still, he says human error remains the most likely reason for contamination, as a certain amount of manual intervention remains a necessity.
The Premium do Brasil and Carlos Fischer, for example, are highly automated vessels, but they still require human involvement, particularly during the fill and withdraw process. During loading and discharge, the ships use stainless steel pipe manifolds onboard and on the shore side. Food grade hoses connect the two manifolds. But the piping manifolds and the hose have to be sterilized before product is pumped through them. "There is always a potential for contaminating the product with microorganisms if the sterilization is not performed properly," says Nicol. To help prevent against contamination, the ships’ pumps and valves are outfitted with specialized sealing mechanisms designed to prevent the introduction of microorganisms.
The future of bulk aseptic storage and transport on the high seas looks promising, as Citrosuco has been successfully operating bulk aseptic ships since 1993. Dr. Nelson says he isn’t aware of any new development in bulk aseptic shipping technology, but he certainly wouldn’t rule it out. "If anyone would have told me 20 years ago that we’d be moving single-strength orange juice, I would have said they were crazy," says Dr. Nelson.
Matt Migliore is the editor of Flow Control. He can be reached at mmigliore@grand viewmedia.com or 610 828-1711.
