Energy efficiency: mechanical processing technology with great potential

Mechanical processes such as conveying, crushing, mixing and drying are real energy guzzlers. To meet economic and ecological requirements, companies are increasingly relying on energy-efficient machines and components. At POWTECH TECHNOPHARM in Nuremberg, innovative technologies that reduce energy consumption and operating costs will be presented again this year.

Written by Armin Scheuermann

Tube chain conveyor at a stand at the POWTECH TECHNOPHARM trade fair — Mechanical processing technology involves many energy-intensive processes – not least because large masses have to be moved. Energy efficiency is therefore the top priority.

The air and floor vibrate, heat rises and the noise makes it difficult to communicate: whether food, detergent or building materials – anyone who has ever stood next to a mixer or dryer in a production hall can feel the enormous energies at work here. Huge quantities of material are not only moved, but also transformed.

Mixing processes are often the core of the production. A lot of energy is needed to homogenise products. Therefore, modern mixing technologies rely on intelligent drive systems and optimised geometries. One example is the Gyraton mixer from Amixon. This machine processes batches of up to 70 m³ and requires only 5 to 10% of the energy of conventional precision mixers. A special tumbling motion of the mixing shaft ensures even mixing even at low speeds. The compact design also reduces the conveying effort and saves additional energy.

A view inside the Gyraton mixer from Amixon — The Gyraton mixer achieves even mixing even at low speeds and is particularly energy-efficient.

But it is not only the apparatus itself that can be trimmed for energy efficiency in mixing systems. There is also efficiency potential in the peripherals. The mixer manufacturer Eirich shows that even existing systems can be made more efficient by modernisation. At Schönheider Guss, an old control system was replaced by a Siemens S7-1515 system, which enables more precise process control and lower energy consumption. The technology for the mixing process and the distribution of the moulding sand were also extensively modernised. A new moisture probe and a redesigned scale with a new dosing device now ensure optimised and more precise water addition and enable a consistently high sand quality. The greatest focus was on the introduction of intelligent sand distribution: this ensures that only the actually required quantity of moulding material is provided.

Energy-efficient centrifuges and decanters – optimised separation technology

Centrifuges and decanters are essential for solid-liquid separation, but consume a lot of energy because large masses have to be brought up to high speeds. New technologies rely on optimised drives and intelligent control systems. HEINKEL has dispensed with hydraulic drives in the new BLUETECTOR peeler centrifuge. Instead, the centrifuge manufacturer relies on an all-electric drive concept that minimises friction losses while offering greater process flexibility. According to the manufacturer, this can save up to 50,000 kWh of energy per year. An optimised CIP system also reduces the consumption of water and chemicals by up to 35 %.

Heinkel Bluetector peeler centrifuge against a dark background — The new peeler centrifuge from Heinkel features an electric drive concept that minimises friction losses.

Competitor ANDRITZ has equipped its decanter centrifuges with the TurboJet-Weir plate. This reduces the flow resistance of the liquid outlet and can lower energy consumption by 10 to 30 % – depending on the operating conditions. The GentleFeeder system also optimises the feeding of the suspension, which means that less energy is required for the separation.

Flottweg relies on a special grid design for the screw body in its current Xelletor machines, which reduces polymer and energy consumption by up to 15% when dewatering sewage sludge. At the Turku sewage treatment plant, replacing an old rotor with a Xelletor rotor reduced energy consumption and increased the dry matter content of the dewatered sludge.

Energy-efficient compressors – potential savings through heat recovery and maintenance

Compressed air is an indispensable source of energy in industrial production, especially for the pneumatic conveying of bulk materials. It enables the gentle transport of sensitive materials, is used for control tasks in many process steps and is essential for numerous machines. However, the generation of compressed air is very energy-intensive and expensive: compressed air systems account for up to 10% of total industrial energy demand. In addition to selecting an energy-efficient compressor, operational optimisation measures offer great potential for savings. These include waste heat recovery, regular filter and oil changes, as well as optimised control of compressed air networks.

Since a compressor converts almost all of its drive energy into heat, this can be used in a targeted manner – for example, to heat production areas or to support drying processes. Kaeser relies on screw compressors with heat recovery that make up to 96% of the energy used available for heating purposes. Fluid-cooled models release about 76% of their energy via the cooling fluid and a further 15% via the compressed air aftercooler. This reduces heating costs and CO₂ emissions.

Infographic showing that 96 percent of the heat generated during compressed air production can be used — 100 percent of a compressor's electrical power consumption is converted into heat. Of this, up to 96 percent is available for reuse in fluid-cooled screw compressors.

Regular maintenance can also make a significant contribution to the energy efficiency of compressed air systems. A clogged air filter can significantly increase a compressor's power consumption. A brand-new filter has a pressure loss of about 10 mbar, but over time this increases due to accumulating dirt. Aerzen has calculated that energy costs of up to €10,000 per year can be avoided by regularly changing filters. High-performance oils such as Delta Lube 06 also reduce friction and extend oil change intervals to up to 16,000 operating hours.

Machine manufacturers focus on sustainability – efficiency targets as a corporate strategy

Not only are the machines themselves becoming more and more energy efficient, but manufacturers are also increasingly focusing on sustainable production processes and internal efficiency measures. Companies in the mechanical process engineering industry are taking responsibility for climate protection by specifically reducing their energy consumption, reducing CO₂ emissions and implementing sustainable energy concepts.

Hosokawa Micron is part of the ‘Learning Energy Efficiency Network’ (LEEN), which supports companies in saving at least 5% energy annually. Measures such as highly efficient compressors, heat recovery and digital energy monitoring are already leading to significant savings. The machine manufacturer uses the GLEM 4.0 energy monitoring system to analyse its energy requirements in real time so that it can implement targeted measures to increase efficiency.

The machine and plant manufacturer AZO relies on energy-efficient operation of its production facilities as part of its sustainability strategy. The company purchases green electricity at all its German locations and operates its own photovoltaic system. In addition, electricity consumption is reduced by using modern technologies and rainwater is recycled for extinguishing and sanitary facilities.

Service technician refilling lubricating oil in a compressor — Regular maintenance of compressed air systems is an essential lever for energy efficiency.

Conclusion: Energy efficiency as the key to sustainable production

Mechanical process engineering offers great potential for reducing energy consumption. Whether mixing, separating or conveying – significant efficiency increases can be achieved in each of these energy-intensive applications through modern technologies and optimised processes. Innovative machine concepts and targeted optimisations in existing plants help to lower energy requirements and reduce operating costs. The machine manufacturers themselves are also increasingly relying on sustainable production processes, digital energy management systems and renewable energies to further boost their efficiency.

These developments show that energy efficiency has long since ceased to be just an economic necessity and now plays a central role in the future viability of industrial processes. The continuous improvement of technologies and operational processes contributes to the conservation of resources, the reduction of costs and the minimisation of the ecological footprint. POWTECH TECHNOPHARM makes it clear that this change is already in full swing and offers companies a wide range of opportunities to future-proof themselves.

Author

Armin Scheuermann

Chemical engineer and freelance specialised journalist