by Rob Cockerill via gasworld
As the world continues to move at an ever-faster pace and from an increasingly conscious mindset, the food and beverages business is having to adapt to even more demanding supply chains and environmental considerations.
Many of the challenges here resides in the cold chain – whether it’s the long range logistics of transporting chilled or frozen food products from source to supermarkets or distribution hubs, or perhaps the growing world of shortrange food delivery services and prepared meals dropped at the doorstep.
There are challenges too, however, in pressurisation and packaging. More specifically, the pressurisation of noncarbonated beverages and the precise packaging of products at risk of spoilage. These are vital considerations before foodstuffs even enter the cold chain.
A significant technology at play in meeting this challenge are liquid nitrogen dosing systems.
Pressurisation and packaging
Since the turn of the Millennium, a two-fold challenge has emerged as a result of consumer trends, perhaps even described as societal megatrends. Firstly, there has been a health-conscious worldwide shift from carbonated soft drinks towards more still and lightly carbonated juices and waters.
Secondly, efforts to reduce the amount of plastic used in each bottle have resulted in more environmentally-friendly packaging. Both trends have arguably been reinforced or accelerated during the last two years in particular; the movement towards sustainability has seriously progressed and further challenged the use of plastics, while the Covid pandemic has intensified health kicks and prompted a pause for greater lifestyle reflection.
What both of these trends have in common, is a resulting lightweight bottle or container that is more susceptible to collapsing during transit and handling. Without the internal pressure of a fully carbonated drink, or with the vessel in ever-larger sizes and ever-thinner wall structures, these PET (polyethylene terephthalate) packages can be unstable.
That’s why liquid nitrogen has been important to the beverages business. Dosing the headspace of the filled bottles with liquid nitrogen pressurises the container and adds rigidity, which helps during packaging and handling. A precise drop of rapidly expanding liquid nitrogen into hot and cold-fill lightweight PET packages and aluminium cans allows for consistent pressure from package to package and eliminates panelling and palletising problems.
At the same time, the demand for fresh foods and produce has also grown, which itself requires an inert atmosphere to prevent the spoiling of those products and extend their shelf life to not only survive the transiting of supply chains but elongate the window of storage in consumer cupboards and fridges. The aim here for food producers and packagers is to purge and/or inert the packaging and, therefore, reduce the risk of oxygenation that can lead to spoilage.
Whilst not used for fresh food applications, liquid nitrogen dosing achieves just that objective across frozen foodstuffs and their packaging.
Boston, Massachusetts-based Vacuum Barrier Corporation (VBC) ia a leading manufacturer of liquid nitrogen transfer systems. As a supplier of liquid nitrogen systems since 1958, the company has an in-depth knowledge of specialised cryogenic processes.
Vacuum Barrier designs, engineers and fabricates liquid nitrogen handling systems in its Massachusetts facility for various applications that include food and beverage, semiconductors, pharmaceutical and biotech. This expertise is rolled out worldwide by Vacuum Barrier’s select group of highly trained distributors.
Mike Johnson, Vice-President of Sales for VBC, explains the role of dosing systems in the food and beverages business – and why it’s very much a matter of precision. “Any bottling or canning operation will be looking for consistent pressurisation or inerting of their containers,” he says. “This requires the doser to consistently output an accurate dose of liquid nitrogen, whether dosing discretely or steadystreaming.”
“Too small of a dose can lead to unstable containers and the possibility of collapse. If dosed with too much nitrogen, there is risk of containers bulging or bursting, which could cause jamming and downtime.”
“The challenge for the dosing equipment is to reliably and accurately control the liquid nitrogen (LN2) dose for each container, at speeds up to and over 2,000 bottles per minute.”
“The doser does have the ability to adjust to changes in line speed of the filler. As the line ramps up or down, timing is adjusted automatically to ensure each dose enters the container. Likewise, dose compensation adjusts the amount of LN2 dispensed as the line speed changes. For example, as a line slows down there is more time between filling and capping, which means more time for the nitrogen to boil-off. Therefore, a larger dose is dispensed to maintain consistent pressures.”
Johnson acknowledges that other factors on the production line must be taken into account as well, to ensure proper pressurisation. These include the travel time from the doser to the seamer or capper, which should be minimised to prevent excess boiling or loss of nitrogen, while any shaking or bouncing of containers on the conveyors can both force nitrogen and product out of the package before its closure. Once the package does reach the closure stage, Johnson says, reliable sealing closures are also required to maintain the pressure within the container after dosing.
VBC offers a unique range of vacuum jacketed lines and cryogenic transfer systems for various applications, from short flexible hoses to large plant distribution systems, and is confident of handling projects big and small. For the food and beverages business in particular, the company specialises in specific cryogenic process equipment such as these invaluable liquid nitrogen dosing systems.
“We provide multiple options when it comes to selecting a doser for your line,” Johnson affirms. “Our dosers address line speeds of 200 to 2,000+ BPM. Our systems have always and will continue to evolve with the demands of the industry.”
Where accuracy is so key, VBC is able to provide systems with the greatest precision of dosing accuracy.
Cost, efficiency and safety
Arguably the jewel in the VBC crown for these applications, is its NITRODOSE® liquid nitrogen injection systems, used to pressurise and/or inert delicate packages, like cans and PET bottles. A drop of liquid nitrogen is injected into the headspace of a container before capping or sealing, adding strength to thin-walled containers or reducing the headspace oxygen content that would otherwise degrade a sensitive product.
Various types of NITRODOSE® Liquid Nitrogen Injection systems are available for different requirements. What they all have in common, however, is the ability to maximise investments, efficiencies and safety – all key factors in a consumer market such as food and beverages.
“Cost is another key consideration of production facilities, and it’s important to look at the full picture when measuring costs of an LN2 system,” Johnson explains. “Up front purchase price, installation, and operating costs must be considered jointly. When evaluating tank options, large bulk tanks cost more initially, but nitrogen is less costly in bulk. The need to continually change out dewars during a production run can also add hidden cost.”
gasworld understands there is a further efficiency factor of note, with liquid nitrogen dosing understood to potentially reduce nitrogen consumption by as much as 80% when used instead of gaseous nitrogen tunnel systems. At a time when quality, nutrition and consumer convenience dominate food and beverage business demands, and concerns over environment and sustainability dominate their products’ packaging, the ability to provide such solutions and efficiencies is surely a win-win situation.
Of paramount importance though, is hygiene and safety. NITRODOSE® systems are able to maximise both of these critical control elements. “All NITRODOSE systems are designed without any nooks or crannies that collect dirt and germs and all hardware is captivated. We also provide CIP protection that withstands high pressure wash or aggressive chemical clean up,” Johnson assures.
“It is important to address worker and machine safety when dealing with liquid nitrogen. When boiling from a liquid to a gas, nitrogen expands roughly 700 times. Safety relief valves are installed on tanks, piping, and dosers to prevent over pressurisation and potential equipment ruptures. Where there are shut-off valves in a system there is potential for nitrogen to be trapped. A safety relief valve must be placed between any two such valves. “
“On bulk tank-fed systems, the lowest-rated relief device typically is placed outdoors. If a safety relief valve does relieve, it is safer if it happens outdoors rather than inside where workers are present.”
VBC believes the future growth in liquid nitrogen dosing systems could be driven by faster line speeds in the food and beverages sites themselves, perhaps a reflection of that trend for ever-faster turnaround in the sector as a whole.
“Much faster line speeds will require dosing systems to meet those speed challenges while maintaining accuracy with minimal maintenance,” Johnson says. Yet other pockets of opportunity also exist in dosing systems, with the high-growth cannabis market a prime example.
The cannabis trade has been one of the hot new applications in recent years, where the loosening of recreational cannabis regulations has been a major driver of growth in carbon dioxide (CO2) utilisation in various countries. The recreational market in Canada is now large and established, but the US is the world’s largest market, with many states allowing the use of medical cannabis for some therapies. If some states were to legalise recreational use, this would further expand the US market potential – and many believe the growth of the cannabis market offers the biggest expansion in the CO2 business today.
With the need to not just grow that cannabis at scale but package it too, the opportunity is not just limited to CO2, as Johnson explains. “The legalisation of both medical and recreational cannabis has created the need to improve the packaging process of marijuana. As the industry grows, so does the need for quality control and storage.”
“Packaging individual portions of the cannabis flower in hermetically sealed tins, bottles, or jars is rapidly gaining popularity. When exposed to oxygen, the active compounds in cannabis, THC and CBD, begin to degrade, along with its efficacy. Dosing these containers with liquid nitrogen purges the oxygen from the package prior to sealing, reducing the oxygen level, and extending shelf life.”
THE ROLE OF LIQUID NITROGEN DOSING SYSTEMS IN FOOD AND BEVERAGES
Liquid nitrogen dosing provides several functions:
- Pressurisation for package stability of non-carbonated beverages – water, juice and teas to name a few.
- Inerting for oxygen reduction to extend shelf life and prevent package panelling – such as oils, fruit juice, wine and snack foods.
- Nitrogenating beer and coffee to achieve the smooth, creamy, and attractive cascade effect after pouring, with or without a widget.