Yoghurt provides a perfect illustration of developments within the wider food industry, where the number of product lines has ballooned.
The latest fashions in fruity flavours, low-fat, creamy, Greek and Greek-style, layered, organic, premium, budget and even dairy-free alternative ranges are all jostling for space on supermarket shelves.
For manufacturers, this proliferation of consumer choice can mean ever-shorter production runs and more changeovers. It can also mean more product losses and a lot more waste.
Frequent product changes on the same manufacturing line with intermediate line cleanings make product recovery even more essential to reduce waste and associated costs
Paul Cardon, industry product manager with Mouvex
Minimising the waste generated during product changeovers makes sense in any process plant. In the case of food and beverage manufacturers, the high prevalence of short production runs and the need for hygienic cleaning in between means that the pressure to recover product and minimise disruption can be even higher than elsewhere.
“Frequent product changes on the same manufacturing line with intermediate line cleanings make product recovery even more essential to reduce waste and associated costs,” says Paul Cardon, industry product manager with Mouvex, a member of PSG, which is part of the Dover group.
Mouvex makes eccentric disc pumps, which can happily continue to pump product through pipework and associated kit at the end of a run, even when the equipment contains a growing proportion of nothing but air. This ability enables typical increased product recovery rates of around 60 to 80%.
Many food manufacturers face considerable economic uncertainty going into 2017, putting them under renewed pressure to improve yields and reduce waste in an effort to maintain margins.
In addition, initiatives such as the European Union’s Circular Economy Package are putting waste under the political spotlight. Levels of waste that might once have been viewed as an acceptable cost of doing business are coming under increasing scrutiny.
“Just like any other, the food industry is looking for savings. For a long time, the focus was on reducing energy consumption but, more and more, waste reduction is considered as a serious way of reducing costs and increasing profit,” says Cardon.
“In addition, as there is a growing concern regarding food waste worldwide, a company doing waste reduction can highlight itself as being a virtuous one. So waste reduction can bring both savings and company image improvement.
As there is a growing concern regarding food waste worldwide, a company doing waste reduction can highlight itself as being a virtuous one. So waste reduction can bring both savings and company image improvement
“Growing hygienic concerns, as well as food waste reduction objectives, are increasing the importance of product recovery. Until quite recently, waste was considered by many companies as something unavoidable, against which more or less nothing could be done. That’s no longer the case,” he says.
It is not only a loss of valuable product that is at stake when the inside of pipelines and associated equipment are left coated with product at the end of a run.
Cleaning systems can account for up to 70% of water use on a typical food production site, generating a large volume of dilute waste that then needs to be treated.
“A piping system in which significantly less product is left behind will definitely need less water and detergents to be cleaned,” says Cardon.
“In addition, the time needed for cleaning will be reduced as there will be less materials to remove. Energy consumption due to cleaning, as well as wastewater and detergent treatment costs, will also be subsequently reduced.”
Mouvex says its eccentric disc pumps offer a straightforward product recovery solution compared to some of the alternatives. They don’t need any peripheral equipment and they can push residual product successfully through virtually any arrangement of pipework and other equipment, such as valves or heat exchangers, for example.
However, alternative solutions based on pigging promise even higher recovery rates, although their use can be more restricted.
The increased importance given to environmental sustainability amongst food and beverage manufacturers is a big driver
Peter Elgar, group marketing manager for HPS Product Recovery Solutions
Peter Elgar, group marketing manager for pigging system supplier HPS Product Recovery Solutions, agrees that it is a combination of factors that are boosting current interest in product recovery: “As a company we are finding an increasing demand for our products. This is due to a combination of things, but the increased importance given to environmental sustainability amongst food and beverage manufacturers is a big driver.”
“Because pigging saves significant amounts of product, reduces water consumption and the use of cleaning chemicals, and so also reduces overall waste and associated disposal costs, it helps towards the environmental sustainability goals of our customers.
“At the same time, it increases product yields and speeds up processing, which gives our customers high ROI and increased profits. So while sustainability is a big factor, it’s a combination of the sustainability and financial benefits pigging brings that is really driving things.”
In essence, pigging involves launching a flexible plug through the pipework under pressure, pushing almost all the remaining product out as the pig travels between dedicated launch and receive stations. HPS systems rely on solid-but-flexible pigs with a flexible magnetic core.
“This flexibility is important because it means they can travel around bends in pipes while maintaining full contact with the inside of the pipe. This in turn means they recover the maximum amount of product (up to 99.5% of residual product left in pipes),” says Elgar.
“Most of the larger plants use pigging because they have a lot to gain – the more length of pipeline, product variations and capacity you have, the more product there is to recover and waste to reduce.
“That’s not to say smaller operations can’t benefit from pigging, particularly if they have a high-value product, have a high CIP [cleaning-in-place] requirement, or are in a competitive market. Basically, any liquid food or beverage product that is pumped, can be pigged,” he says.
Most of the larger plants use pigging because they have a lot to gain – the more length of pipeline, product variations and capacity you have, the more product there is to recover and waste to reduce
For example, he notes that one UK-based soft drinks manufacturer uses HPS systems to clear product between its tanks and a filling machine, delivering an increase in yield equating to 48,000 extra cans of drink per week.
Meanwhile, a wine producer estimates that it’s saving some 40 million litres of water and recovering an extra 440,000 litres of wine per year using HPS pigging systems.
Pigging is a well-established technology. However, that has not prevented some suppliers from attempting to build on the original technology with innovative solutions.
For instance, ice pigging is designed to deliver more flexible product recovery. Instead of a solid pig, the technology pushes a plug of ice through the pipework. This slurry is extremely flexible and can pass through spaces that would spell the end of the line for a solid alternative.
Developed at the University of Bristol and now offered by Suez Advanced Solutions UK, ice pigging initially found favour commercially when offered as a service in the water industry.
The ‘as a service’ model suits applications where companies need pipes cleaned occasionally, rather than on a daily basis. However, ice pigging now looks set to become a player in the food and drink industry with the arrival of the AQL500 system, which can be permanently installed on-site to provide on-demand ice pigging.
“We’ve only recently launched the product for the process environment. A food company might need pigging eight times a day,” says Matt Stephenson, business unit director for ice pigging.
The ice properties don’t vary much between applications, although the additives used to control its freezing point can be tailored to suit.
In food applications, these additives are generally simple food ingredients or additives that are chosen to be totally safe and compatible with the products being handled.
According to Stephenson, recovery rates vary between around 70% for runnier products that tend to mix with the ice and 95% for more viscous products, depending on the pipework.
“Ice pigging doesn’t give bacteriological cleanliness but it removes the product. If you need more than that you’ll need to follow with CIP, but because you’ve already removed everything it’s a much reduced process,” explains Stephenson. “We use a few litres of ice versus 1,000 litres of hot water for conventional CIP, so there are big savings.”
In another variation on the pigging theme, Martec offers a system based on its patented Marplug design. Rather than being a solid plug the Marplug comprises a series of flexible, circular blades around a central core. These blades act rather like the blades of a squeegee against the pipe walls.
Martec has also developed a detectable version of the Marplug, so that if its blades are damaged, any stray material should be picked up by the routine checks that food firms make for foreign bodies using metal detectors. Managing director Ian Sterritt says that in addition to recovering wet products, one of the latest areas that Martec has been exploring is powder recovery.
“We are at the leading edge of what powder pigging is about,” he says. “Food companies move products such as bread premixes or dry batter ingredients using pneumatic conveying. Some may include ingredients such as parsley or pepper or allergens like whey powder, so manufacturers can’t cross contaminate between batches.
In-plant product recovery can only ever be part of the solution when it comes to reducing food waste. However, it is also an approach that can boost profits, as well as environmental performance
?“One of our clients wanted to test the Marplug. We weren’t convinced it would work so we agreed to carry out a no-risk project with the client and to our surprise it worked really well. The equipment at each end still goes through the manual cleaning process, but the pipework is cleaned by a Marplug, which can wipe the inside of the pipe within 60 seconds. It’s quite a radical step forward.”
While more conventional pigs are moderately flexible, Sterritt says that the Marplug can achieve a more thorough clean on pipework that is dented or otherwise less than perfect.
“With powder applications in particular, the walls of a pneumatic conveying system are generally much thinner than pipes carrying liquids so they’re more susceptible to damage,” he says. “Sometimes they’re not even round. They could be oval but the Marplug would still work.”
In-plant product recovery can only ever be part of the solution when it comes to reducing food waste. However, it is also an approach that can boost profits, as well as environmental performance. ?