GEA 4-bar process valve actuators lead the way 16% energy savings through reduced air pressure

Phil Black - PII Editor 25/09/2023

279 4 minutes read

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In the ever-evolving landscape of food and beverage processing, optimizing costs and reducing the carbon footprint have become key priorities. Compressed air is a particularly expensive form of energy, accounting for a considerable portion of the electricity costs in processing plants.

One important step that can save about 16% of this electricity portion is to reduce the system pressure from the still prevalent 6-bar standard to the more efficient 4-bar pressure.

Process valves are a critical component in this step because they need to be equipped with 4-bar actuators to enable the reduction, and these specially adapted actuators can be difficult to obtain.

GEA has now made suitable 4-bar actuators available for all relevant valve applications and process steps – a world first that can help more companies to make this cost-effective, climate-friendly improvement.

While air itself may be free, compressed air deserves more attention than it has received in the past. Energy costs are an increasingly dominant cost factor in most industries and compressed air is regularly described as one of the most expensive, least efficient forms of energy.

How much compressed air contributes to the plant’s total energy bill can vary from industry to industry: GEA customers in the food and beverage industries report that it accounts for about 10% to 15%, and this can add up to several 100,000 EUR energy costs per year for compressed air in just one plant.

Low air pressure – high savings potential

Relevant technical and environmental organizations, such as the Fraunhofer Institute for Systems and Innovation Research and the German Federal Environment Agency, have addressed the problem of inefficient compressed air systems and have identified significant energy savings that can be achieved through system upgrades.

Recommended improvements range from installing more energy-efficient compressors to using heat exchangers for energy recovery and various programs aiming to minimise leakage. One particularly promising step is to reduce the system pressure for the compressed air applications throughout the plant, and this stands out as a relatively simple and efficient strategy for both existing and new installations.

According to a study conducted for the German Federal Environmental Agency, a 1-bar reduction in system pressure can save around 8% of the electricity required to operate the compressor stations. This means a potential 16% savings in compressor electricity if the system pressure is reduced from 6 bar to 4 bar.

Lower pressure also means less friction in the air ducts and less leakage, contributing to the 16% savings from a 2-bar reduction. Leakage losses typically account for about 10% of total compressed air volume in medium-size operations, and a 1 bar reduction in system pressure eliminates about 1/8 of these losses, even without improving existing air leaks.

Lower air pressure and less leakage also reduce the amount of painstaking hygienic cleaning, conditioning and disposal of compressed air required in most food and beverage operations.

How much does the 16% savings potential add up to? For an example beverage processing plant in Germany that uses 864,000 kWh of energy annually for its compressed air supply, the savings from a 2-bar reduction in system pressure would result in a 42,000 EUR energy cost reduction per year.

Pneumatic process valves – how much pressure do they need?

Pneumatically actuated process valves are a central element of automated process control and can be considered a key application of compressed air in food and beverage plants.

The need for reliable valve operation to ensure safe processes has been a major reason why companies have traditionally been advised to set their system pressure at 6 bar or even higher, driven by the notion that only this can ensure fail-safe opening or closing of the valve.

As a result, most plants today have their system pressure set to this 6-bar minimum. Most valves installed have been designed and implemented with 6-bar actuators.

However, advances in modern valve technology have changed the perspective on safe valve operation: Today, valve actuators operating at a reduced pressure of 4 bar can deliver the same level of reliability and performance. This allows companies to achieve optimal efficiency and energy savings without compromising the effectiveness of their automated processes.

Empowering more plant operators to make the switch: 4-bar valve actuators in a complete selection

Setting up an energy-efficient 4-bar compressed air system or modernizing an existing system in this respect requires that all connected devices can be equipped with the appropriate 4-bar actuators.

In a pioneering move, technology provider GEA has made this option available for the majority of hygienic seat valves (single-seat and mixproof) in the modular GEA VARIVENT® series, covering all shut-off and divert applications in hygienic processes as well as special valve functions and valve variants, and for all GEA Hygienic butterfly valves.

The 4-bar actuators can be retrofitted to existing valves and integrated into newly ordered valves or valve manifolds.

A reduction to any intermediate pressure level between 6 bar and 4 bar can also be effortlessly achieved with the valve configurations now available from GEA. This can sometimes be necessary to accommodate specific compressed air applications that require, for instance, 5-bar air pressure.

GEA Hygienic valve types available/retrofittable with 4-bar actuators:

GEA VARIVENT® Hygienic single seat valves (shut-off and divert valves)
GEA VARIVENT® Hygienic mixproof valves (shut-off and divert valves)
GEA VARIVENT® Hygienic special application valves
GEA VARIVENT® Hygienic PMO valves for the U.S. dairy market (coming soon)
GEA Hygienic butterfly valve
GEA Hygienic leakage butterfly valves

The wide-range availability of suitable valve configurations from GEA enables many plants to switch to a lower system pressure. Other processes using compressed air in the food and beverage industries typically require pressures lower than 4 bar.

They can continue to be served by the same compressor station as the valve control air system after the system pressure is reduced to 4 bar. Such processes include, for instance, conveying or aerating media and ingredients, filling or emptying storage tanks, and air blast cleaning.

By embracing this new approach to saving energy through a system pressure reduction to 4 bar, companies can significantly improve the sustainability and cost-effectiveness of their operations in the long run.

GEA Flow Components

GEA Tuchenhagen GmbH
Annekathrin Bibow
Phone +49 4155 49 2421
annekathrin.bibow@gea.com
www.gea.com/flow-components