Energy-efficient conversion of pellet dryers

Rising energy costs around the world are stifling the value creation potential of plastics processors. Energy-efficient processes and process components are now more important than ever when it comes to company competitiveness. The goal of climate-neutral production is also increasingly gaining the attention of processors. The further development of Blue Air Systems' process air technology now results in very high energy savings of 50–70% compared to conventional hot-air pellet dryers. This enormous cost-saving potential is now available with Blue Air Systems' technology.

The development of the Blue Air Dryer module, or BBX for short, benefitted from Blue Air Systems’ decades of experience with dry process air systems for drying pellets. Blue Air Systems has focused on intelligent energy use in its hardware solutions under the motto “Total Energy Savings”. The Blue Air Dryer module uses dry process air to convert conventional pellet dryers and opens up new potential for plastics processors keen to improve their profitability and maintain their competitive edge. The Blue Air Dryer module transforms pellet drying into an energy-efficiency booster. For new applications or for retrofitting existing systems, the Blue Air Dryer is the alternative to “energy-guzzling” dryers. Conversion is very simple as existing pellet hoppers remain in use. Only the drying unit is replaced with the compact Blue Air BBX Dryer module. Blue Air Systems has filed a patent for the innovative Blue Air Dryer module. At the same time, the company says it is open to cooperation to cover important markets in America and Asia.

Blue Air Dryer BBX module for converting pellet dryers to a cold process air system. (Image: Blue Air Systems)

Pellet drying is decisive for component quality

Pellet drying plays an important role in plastics processing in order to maintain residual moisture content of the materials within parameters immediately prior to processing. Pellet drying systems make a significant contribution to meeting quality requirements for components in injection moulding, blow moulding, and PET processing. Processes with small, medium, or large material throughputs, as well as those with material changes, require different process design approaches to deal with over-drying, re-moistening, dedusting and cleaning in a manageable way. There are two classic processing strategies: central material supply systems (central dryers) and decentralised material supply systems (top-mounted or stand-alone dryers), the use depends on throughput and material changes. Furthermore, a distinction must be made between batch or portion dryers and continuous dryers. Very large centrifugal dryers with throughputs of up to approximately 100 t/h predominate in pellet production. Visualisation systems as well as dew point and moisture measuring devices result in technically sophisticated, application-specific, optimal drying of pellets. In addition to maintaining residual moisture content tolerances, the energy efficiency of a drying system is very important. The market is dominated by adsorption dryers or molecular sieve dryers, whose energy efficiency is lower than that of process air dryers. In the case of an adsorption dryer or molecular sieve dryer, deep-drying, hot air flows around the pellets, absorbing their moisture before transferring it to a desiccant. Potential weaknesses of this strategy include high operating costs for regeneration and suboptimal energy use at small and medium material throughputs. However, these dryers excel at high pellet throughputs exceeding 1,000 kg/h. The innovative and highly energy-efficient Blue Air Dryer technology, with an enormous range of process volumes from 0.5 to 10,000 kg/h, guarantees the best drying results – pellet for pellet. The Blue Air Dryer combines minimal operating costs, high availability and maximum energy efficiency with virtually maintenance-free processing.

Schematic view of a converted pellet dryer with the Blue Air BBX Dryer module for efficient and gentle material processing. (Image: Blue Air Systems)

A game changer for drying pellets

The main energy savings come from the drying method used in the Blue Air BBX Dryer. Unlike conventional drying strategies, a Blue Air Dryer requires no regeneration energy. The Blue Air Dryer not only enables a constant dew point without any fluctuations, but also does not require cooling water or a molecular sieve during operation. Drying is remarkably low-maintenance: The Blue Air Dryer only requires an air filter change after a long period of use. The extremely compact Blue Air Dryer modules can be used for a wide range of hopper sizes up to 10,000 kg/h, for PET applications up to 1,000 kg PET/h as standard, and even more for tailor-made systems, available upon request. The installation of the Blue Air Dryer module is also extremely straightforward thanks to a plug-and-play design and can be completed in one day. The result is comparable or better drying quality, but with significantly improved energy efficiency.

The energy-saving potential of pellet drying with the Blue Air Dryer module is decisive. Drying pellets with the Blue Air Dryer module realizes maximum energy conservation: Depending on the application, a Blue Air BBX Dryer module can save 50–70% energy when it replaces a conventional pellet dryer. Bernhard Stipsits, Managing Director of Blue Air Systems, explains: “When we look at global markets, we see a very high potential for retrofitting installed drying systems with the Blue Air BBX Dryer module for energy-efficient drying.”

The efficient Blue Air Dryer technology featuring intelligently optimised energy consumption can be connected to any drying hoppers. The advantage here is that thanks to intelligent digital pneumatics, only the exact amount of process air required to complete the drying task is used. A finely stepped dry air volume flow control of the Blue Air Dryer module ensures maximum transparency of the drying process: An optional database is available for plastic-specific and throughput-dependent dryer settings, a fill level sensor, and, as standard, a display of the process parameters, including temperature, dry air volume flow, dry air dew point and energy consumption at the current throughput.

Process air system and the advantages of Blue Air Dryer

Bernhard Stipsits, Managing Director of Blue Air Systems GmbH, talks about the Blue Air BBX Dryer Module and how it can help achieve efficiency.

Mr. Bernhard Stipsits, Managing Director of Blue Air Systems

The market for drying systems for pellets is dominated by molecular sieve dryers. Why should a plastics company now switch to a process air system?

Mr. Stipsits: In fact, only a handful of suppliers use the process air concept. The current market penetration of molecular sieve dryers for drying process air has historical reasons. However, energy costs play a much larger role in calculating pricing of moulded parts by plastic processors today than in the past. Drying pellets with the Blue Air BBX Dryer Module realises maximum energy savings: Depending on the application, a Blue Air BBX Dryer Module saves 50–70% energy when it replaces a conventional pellet dryer. The conversion is extremely simple: The existing pellet hoppers continue to be used. Just the drying unit itself is replaced with the Blue Air BBX Dryer Module. The Blue Air BBX Dryer is a real game changer. This has not just caught the attention of processors: it is an important factor in increasing their competitiveness.

You developed the Blue Air Dryer module for the purpose of converting third-party systems. How do you see the opportunities this presents?

Mr. Stipsits: Energy efficiency is a strong trend, and it is increasingly a competitive factor. As mentioned, the potential of our technology to improve energy efficiency in pellet drying is clear to see. The Blue Air BBX Dryer module offers a very straightforward entry point into this technology to leverage these energy savings.

Do ever-increasing energy costs play a decisive role in your strategy?

Mr. Stipsits: They certainly do. The cost of energy consumption is one part of this. But the ecological footprint, in terms of “climate-neutral production,” also comes into play. These are two important trends for processors. We have filed a patent application for the Blue Air Dryer module because the Blue Air Dryer addresses both trends. Moreover, based on our decades of experience developing dry process air systems, we are convinced that using in-house process air for drying is the superior approach. When we look at global markets, we see a very high potential for upgrading existing drying systems with the Blue Air BBX Dryer module for energy-efficient drying.

How are you going to convince the market?

Mr. Stipsits: On the one hand, we intend to market the Blue Air BBX Dryer through our worldwide sales and service network. On the other hand, we are open to cooperation with partners. This should be particularly interesting for global markets such as the Americas, Asia, Africa, and the Middle East. Regional partners could serve these markets at a local level. We are looking for such strategic partnerships to achieve increased market penetration.