Filling warmer and saving energy

Jeff Smith works in a beverage company that has specialised in the production of soft drinks. As Sustainability Manager, he has been tasked by the managing board with investigating how energy can be saved in production. Firstly, of course, he needs to think like an entrepreneur and optimise production costs. Secondly, the company is also aware of its responsibility for the environment – which is why it has set itself the goal of reviewing its production processes with a view to implementing cost-cutting measures.  

One option is to save energy in continuous operation – and there are actually a number of possibilities here. But which one is efficient, too? In other words, where can a tangible result be achieved as quickly as possible and at minimum expense? That’s precisely the question with which Jeff Smith approached Krones, because for a good few years now the company has been using a PET line from Krones for bottling cola and lemonade beverages. And the filling process is also exactly where many companies can unlock plenty of potential savings.  

The filling process in focus 

Jonas Sittenauer, a member of the sales team for Lifecycle Service, explains why this is so: “In the commissioning process, our current CSD fillers are set to filling temperatures of about 20 degrees Celsius. For older models the figure was often about 16 degrees.” During operation, however, these figures no longer reflect the reality, he goes on: “When I talk to customers who have been operating their lines for a few years, it often turns out that they now only fill at twelve to 14 degrees – even though they are perfectly capable of more.” But why don’t they do so? “There may be a number of reasons for this, but the most frequent is that colder filling temperatures mean production is more stable, as the beverage foams less,” says Jonas Sittenauer. Good for performance, then, but with room for optimisation when it comes to cost savings and sustainability! 

It is precisely this potential that Krones is now identifying and leveraging by examining, together with its customers, whether filling temperatures can be increased without any loss of performance. “It’s not rocket science, it's just a question of fine-tuning the machines – and this can be quite tricky when we get close to the limits. But by doing that, of course, we’re helping the customer find the perfect parameters for their products,” says Dr. Valentin Becher from the Krones development team.  

Step 1: Acquisition and analysis of the data 

To help him do so, he developed a questionnaire that Jeff Smith is now filling in. On it he records the recipes for the individual beverages, the bottle volumes, the permitted maximum pressures and expansion of the PET containers, production speeds, other details relating to the factory and the temperatures to which the product will be exposed later on in the value chain. Dr. Valentin Becher then analyses all these values and uses a new, detailed process model of the production line to determine a maximum possible filling pressure for each beverage-container combination, from which a maximum filling temperature can then be calculated.  

In the next step he passes on all values to Johannes Vogl from the Filling Technology team, who verifies whether the filling process contains time reserves that can be utilised, since higher temperatures mean that more time is required for filling. He then calculates the maximum treatment time that is available without impacting on performance, because the treatment time correlates with the temperature. “Our calculations are based on the combination of filler design, bottles and beverage show values of 24 to as much as 30 degrees Celsius. Whether these can actually be realised directly in the field depends on a lot of different factors, however. That's why we always wait until we’re on site before approaching this temperature range when we slowly increase the temperature. It goes without saying that the priority is always for production on the line to continue without restriction,” says Johannes Vogl, and Dr. Valentin Becher adds: “At the end of our calculations we have an individual recommendation of the possible filling temperature per beverage-container combination – and hence a customised package for reducing the energy demand of that line.”  

Step 2: Realisation on site

Next, Krones presents all these calculations to the customer, followed by a joint discussion on further steps. These lead from theory on the laptop to real life on the filler. “Even once we’ve done all the calculations, after all, ultimately we have to make sure it will work in the field,” says Johannes Vogl.  

It goes without saying that the priority is always for production on the lines to continue without restriction. Johannes Voglfrom Filling Technology

Krones then gets together with the customer’s team to find the perfect filling temperature for day-to-day operation – while production is still continuing! “From the analysis we know what the maximum possible would be and approach these values per SKU*, i.e. the type of beverage and bottle size, step by step. Production continues as normal, of course,” Johannes Vogl adds. Even if the ultimate decision is to set the filler at “just” 20 degrees Celsius, that’s still a pretty good result. “From 12 to 20 is a jump of 8 degrees – and of course it has a noticeable impact on energy demand from the very first second,” Jonas Sittenauer emphasises. 

* SKU: Stock Keeping Unit 

From 12 to 20 is a jump of 8 degrees – and of course it has a noticeable impact on energy demand from the very first second. Jonas Sittenauerfrom LCS Sales

Step 3: Optional software components and upgrades 

Why is there often a limit at 20 degrees Celsius – even though it could actually be a lot higher? “You need to ensure that production is stable, of course. With older lines especially, though, that requires even more manual activity in terms of operation – and the personnel do not always have the necessary knowledge to operate the filler at the limits of its settings safely and efficiently on an ongoing basis,” says Jonas Sittenauer, explaining the first step of a rather conservative approach to temperature adjustments. But of course, even more can be teased out in terms of warm filling – with various upgrades that support the operating staff.  

Firstly, there are software components such as Cluster Filling or Dynamic Filling Pressure Control, which make it much easier to start up again after production has come to a standstill: Instead of running the filler at full power again straight away, upgrades such as these ensure that the speed increase and pressure control are adjusted automatically. This eliminates the risk of a foaming product – and hence compromises in terms of output and quality – because the production speed is ramped up too quickly. What’s more, it doesn't even require the operator to do anything. “When you bear in mind that machines come to a stop multiple times per shift, particularly in the case of older lines, this definitely makes the work of the operators on the line considerably easier while at the same time ensuring higher and more stable production,” says Jonas Sittenauer. 

Secondly, Krones also offers other upgrades for bringing the higher CO₂ consumption caused by the higher filling pressures back down again. There are a number of options for the mixer. One of them is the adjusted pressure control system. In the event of a production stop at the filler, the Contiflow only remains in production until a fill level is reached in the tank which requires a CO₂ discharge. Instead of discharging CO₂ into the open, though, the Contiflow will also stop production. Once the fill level in the tank drops again, production can be resumed quickly. The continuous supply of the filler with product is thus ensured at all times. Another possibility offering a major savings potential is the use of nitrogen or compressed air instead of CO₂ during production. In this case, CO₂ is only used while the line is being started up. Experience has shown that changing the product gas does not have any negative impact on quality, but this option is primarily recommended for products that are not sensitive to oxygen. There is a similar possibility with the filler, too. Here, for instance, sterile air can be used instead of CO₂ after production start-up, as soon as the system has been filled and is running stably, in order to maintain the counter-pressure.  

The whole line in view 

That Krones takes a holistic view of the line when it comes to warm filling is evident not just from the upgrades available for the mixer, however. Another example comes to the fore in regions with high ambient temperatures and humidity, because here the temperature difference at the cooler can be reduced as well as the temperature difference at the heater. In hotter countries especially, the untreated water is also warmer than the 16 or even 12 degrees Celsius at which the filler is operated. This means that the water first has to be cooled before it can be used for mixing and cold bottling – steps which can now be dispensed with, depending on the future temperature setting. 

Another benefit is that the temperature difference that has to be compensated after filling is smaller, thanks to warm filling. We’re talking about the heater, which brings the product to a temperature above the dew point in order to prevent condensation forming on the container, thereby ensuring optimal labelling and packaging results. 

“If you look at the production process as a whole, it's a real up-and-down in terms of temperature. By increasing the filling temperature, we’re also lowering the temperature differences – which means we need less energy overall for production,” says Jonas Sittenauer. Concluding, he adds: “We’re optimising not just the filler, but the whole line.”  

We’re optimising not just the filler, but the whole line. Jonas Sittenauerfrom LCS Sales

In the future, such an optimised and comprehensive sustainability concept for lines is to be offered and managed centrally by a team in Line Solutions – for both existing and new systems. The colleagues there will provide customers with general advice around the issue of sustainability in production, above and beyond warm filling. 

Mission accomplished: cost savings and sustainability 

Back to Jeff Smith, though. Together with Krones, he implemented various optimisations on the filler and the adjacent machinery – and clearly accomplished the task set by his board. That's because the production is now running much more energy-efficiently, while at the same time he has been able to relieve some of the day-to-day work of the team on the line. A classic win-win situation for everyone! 

The strategy of the Krones team to establish warm filling of CSD in older filler models is not only a driver of cost savings in continuous operation, but it also demonstrates that sustainable production can be achieved without spending on new machines.