Consumers today demand low-carbon and low-waste solutions. But how can soft drinks producers facing tight margins and fierce competition reduce energy consumption and get more from less? We explain how to square the circle – and reduce costs at the same time.
Sustainability is a strategic imperative in all areas of food production, including beverage. The challenge for producers is to reduce energy use and waste while preserving profit margins and staying competitive. New innovative solutions now make this possible.
When seeking energy savings in soft drinks preparation, the first place to look is mixing. Choosing the right technology can make a huge difference to operating costs and production efficiency.
Here, the smart choice is a radial jet mixer, or RJM, which mixes ingredients faster and more energy-efficiently than conventional alternatives. That is because an RJM mixes product using turbulence, in contrast to traditional mixers that rely on axial technology and mechanical agitators or stirrers.
“The vortex from an axial jet creates an asymmetrical mixing field that forces all the product in the same direction, which reduces mixing efficiency,” explains Thomas Eggler, Design Engineering Manager at Tetra Pak.
“A radial jet mixer uses no mechanical force and instead uses a liquid’s own turbulence to mix itself. This avoids friction, ensures homogenous mixing and is exceptionally fast – four to six times faster than conventional solutions.”
Indeed, an RJM mixes a standard beverage in 2-6 minutes after the last ingredient is added, compared to 20 minutes for traditional mixers. Equipping an RJM with a twin stage nozzle rather than a standard single-stage nozzle makes the mixing process even more efficient and halves overall energy consumption.
“Mixing consumes up to half the energy used in a soft drinks plant, so cutting electricity consumption from mixing by 50 percent is a huge cost benefit as well as being good for carbon footprint,” Eggler says.
Mixing highly viscous ingredients such as gums and some thickeners and stabilisers is traditionally performed with the help of a high shear pump.
High shear pumps use great force to dissolve challenging ingredients but are energy-intensive. New technology now makes it possible to mix high-viscous ingredients and keep energy consumption down.
This is possible thanks to an auto mixing device (AMD), a small unit connected to a radial jet mixer that uses shear force to break up the small powder formations typically found in gums and similar ingredients.
The combination of an AMD and RJM avoids the need to install a high shear pump, which can cost up to five times more than the AMD option, says Thomas Eggler.
“Using an AMD instead of a high shear pump reduces energy consumption by around 60 percent.* In a standard production scenario, we estimate you’ll save €9,800 per year on electricity costs and reduce your carbon footprint by about 48,000 tonnes of CO2 by using an AMD.”
Dust is a constant challenge when processing dry ingredient powders. As well as being an occupational hazard, it is also an expensive source of product waste.
Powder that escapes into the air during beverage mixing is typically trapped in an extraction filter and disposed of. But technology exists to recover and reuse it.
An extraction and recovery system can aspirate powder dust from the feeding hopper and wash it with water into a reservoir, where it is recovered and returned to the mixing process.
“A dust extraction system equal in efficiency to ours aspirates around 0.8 percent of the powder. Assuming the average price of powder, this works out to an average of €21,500 over a year,” says Thomas Eggler.
Finally, you can reduce the number of holding tanks required in your preparation line if you choose the right mixer. We’ve already seen that a radial jet mixer mixes much faster than a mixer with a conventional mechanical agitator. The RJM’s extra speed enables you to operate with a single holding tank rather than the customary two.
How is this possible? During production, a 20,000 litre holding tank empties in an hour and 40 minutes (assuming a line speed of 12,000 litres per hour). Meanwhile, a second mixing tank fitted with a mechanical agitator takes two hours to prepare for production. This means the holding tank will empty before the replacement mixing tank is ready. Hence, a second holding tank is required to ensure continuous production.
An RJM allows you to prepare a new mixing tank in an hour and 30 minutes. Since this is less time than the hour and 40 minutes it takes for the 20,000 litre holding tank to empty, a third holding tank is not required. A saving not just for your bottom line, but for the environment too.
Having one fewer tank in the system reduces the amount of cleaning-in-place (CIP) required, generating additional savings. Using a mixer that avoids splashing decreases water consumption and detergent use even further.
This is best achieved by using a horizontal injector with a radial jet mixer. This combination allows ingredients to be introduced directly into the mix, below the surface. Unlike conventional solutions, which cause splashing and leave residue deposits, this gives a cleaner process that requires less frequent cleaning.
For added efficiency, a radial jet mixer can be fitted with a twin-stage nozzle. Recommended when mixing highly viscous or floating ingredients, twin-stage nozzles offer the possibility to run high-volume CIP via the upper nozzle.
“This is a highly effective way to remove sticky agglomerates like pastes or concentrates and again leads to direct time savings,” says Thomas Eggler.
According to our data, a radial jet mixer with either a single or twin-stage nozzle will reduce caustic soda use by over 50 percent in a 25,000-litre tank and save the producer €7,000 per year in a standard production setup.
* Tetra Pak Preparation system B with inline high shear pump 59 kW and Tetra Pak Preparation system B with auto mixing device, 22 kW, both operating 8 hrs/day, 330 days/yr, 0.1 €/kWh