Energy efficiency is a top priority for the Unilever ice cream plant in Heppenheim, Germany.
Ice cream is refreshing and with its proteins and carbohydrates are considered a source of energy. However, it also takes a lot of energy to mix ingredients like milk, dairy chocolate, sugar, and vanilla beans into the finished product.
Electricity and compressed air play an important role in the thermal and kinetic processes for everything from mixing and extruding the ingredients, deep-freezing to -13°F (-25°C), dipping into various chocolate coatings through to final packaging. Energy efficiency is therefore right at the top of Unilever’s list of priorities. As part of the Unilever Sustainable Living Plan, this global corporation has succeeded in saving more than $186 million in energy costs from efficiency improvements in production alone since 2008.
In the area of pneumatics, the use of innovative developments offers the potential to save energy and thereby lower costs. Toward that end, Unilever installed a pneumatic energy efficiency module at its ice cream plant in Heppenheim, Germany, and in the process, reduced the amount of compressed air used to power pneumatics on its ice cream production lines.
Producing 20,000 Ice Cream Bars Per Hour
The Heppenheim factory is one of the main Unilever production locations for ice cream. Products produced at the plant include the well-known Wall’s line including Magnum, Feast, Viennetta and Carte d’Or. High production quantities form the basis for supplying other parts of the European market.
Just one of the five Magnum production lines in Heppenheim produces more than 20,000 ice cream bars per hour. This requires a lot of energy. In order to reduce the compressed air consumption for pneumatic components, the ability to visualize and measure the compressed air consumption was of huge importance to Unilever. Previously, compressed air consumption on the individual production lines had not been determined.
One production line at the Heppenheim plant produces more than 20,000 ice creams bars per hour.
“Until now we were just unaware,” said Alexander Hemmerich, Automation Engineer at the Unilever Plant, Heppenheim. "Air is not visible, so it is not immediately obvious if the consumption is too high.”
As part of the Unilever Sustainable Living Plan there had already been successes in other areas of the plant. Energy-intensive geared motors were replaced with more efficient ones, achieving energy savings of up to 60%. Numerous 18 kW ventilators in the cooling tunnels, which previously ran for 24 hours in continuous operation, were also converted to frequency converters with variable torque loads. This lowered the energy consumption of the ventilators by around 40%.
Energy Consumption Made Visible
Hemmerich and his team took steps toward lowering compressed air consumption with the installation of the energy efficiency module MSE6-E2M from Festo.
“The energy efficiency module gave us the opportunity to see the amount of compressed air we were using during operation of a line,” said Hemmerich. “In addition, we were able to determine how the compressed air requirement developed when we switched off individual consumers. We were thus able to locate leaks and eliminate unnecessary consumption.”
Housed in a cabinet, the Festo energy efficiency module automatically monitors and regulates compressed air powering pneumatics used at the Uniliever plant to produce the Magnum brand of ice cream bars.
The module automatically monitors and regulates compressed air supply, also actively monitoring the condition of the pneumatic system in real time. Doing so provides access to up-to-the-minute process-related data as well as comparative data over time. Data can help personnel determine historical trends on consumption, the amount of air consumed per product batch, and pressure and flow at the time of a malfunction or bad batch of product.
Based on user defined parameters, the module detects when a machine is idle and automatically shuts off the air supply. When the unit receives a startup signal from an operator, it re-supplies compressed air. In the case of a particularly complex production process, automatic standby detection can be deactivated in favor of manual operation. Compressed air consumption is thus reduced to zero during system down times and breaks.
In addition, one of the core functions of the module is the automatic shut-off of the compressed air in stand-by mode. While closed, the unit monitors the drop in pressure. This measurement provides the baseline of how quickly the system exhausts. Thereafter, the module immediately reports to the system controller an unusually quick drop in pressure, which typically indicates there is a compressed air leak. At the same time, the automatic pressure shut-off function prevents further compressed air consumption while the system is not in operation thus saving energy.
The energy efficiency module also collects all information such as pressure, flow, consumption, and pressure change. The data can be merged centrally with other data points for a detailed understanding of the pneumatic system. These modules are designed to send information directly to PLCs via such communication protocols as Ethernet/IP, EtherCAT, ModbusTCP, PROFINET IO, and PROFIBUS DP.
With an energy efficiency module, the Unilever ice cream plant gains visibility into compressed air powering pneumatics on its ice cream production lines, in turn, helping to reduce compressed air consumption.
Reducing Compressed Air Consumption Step by Step
At the plant, Hemmerich now has access to continuous process-relevant data related to pneumatics on the Magnum machines since the energy efficiency modules regularly exchanges important measurement parameters, such as flow, pressure, and consumption with the machines‘ controller.
“We’ve been able to reduce compressed air consumption on the Magnum production system step by step with the energy efficiency module,” Hemmerich said. “We did not have to add any additional communication or power cables when converting our existing systems.” On the Magnum line, the costs for compressed air consumption were reduced by more than $650 per year.
Author: Randy DeForge - Festo Product Manager
Source: Compressed Air Best Practices - August 2020
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