An Optimal Hybrid PET Air Compressor Installation

High-pressure compressed air plays an important role in the PET blow molding process. Until now, it has always been delivered to the point of use (i.e. the blow molding machine) in the same way:

A central PET air compressor (which can either be a high-pressure compressor or a low- or medium-pressure compressor with a high-pressure booster) is placed in a compressor room. From there, the compressed air is transported to the point of use via high-pressure pipes.

This is also referred to as a “centralized” air compressor installation. In many cases, especially when only low- or medium-pressure air is needed, this is the best approach. The reason is that a fully decentralized set-up with a decentralized air compressor at every point of use is not a feasible option for countless applications that need standard compressed air pressure.

Unfortunately, a centralized set-up and air compressor room design have some costly downsides for the manufacturers of PET bottles, especially as the blow molding pressure continues to decrease. In a centralized system, you can only have one pressure, dictated by the highest blowing pressure needed.

To cope with different blowing pressures, a decentralized set-up is the better choice. However, this would mean that every decentralized unit has to be sized for the maximum flow of every application. This could result in a very high investment cost.

Now, there is also a better, less expensive hybrid solution: decentralizing part of the system.
We can offer a hybrid system installation with a booster near the point of use. Our boosters are designed specifically for this application.

Traditional boosters vibrate too much and are too loud to be installed near the blow molding machine. That means they would violate noise standards. Instead, they have to be placed in expensive sound-insulated compressor rooms.

But not our boosters, which are specially designed for PET bottle production. Thanks to their sound-protecting canopy, a frame and cylinder set-up to minimize vibrations, they can operate at an unprecedented low noise level and the lowest vibration level.

This hybrid system places a low- or medium-pressure PET air compressor in the centralized compressor room and puts the booster, which generates the required higher pressure of up to 40 bar, in the immediate proximity of the blow molding machine.

As a result, the high-pressure air would only be produced where it is needed, at the blow molding machine. Each high-pressure application gets the exact pressure it needs (rather than having one high-pressure flow tailored to the application with the highest pressure requirement). All other applications, e.g. regular pneumatic equipment, would get their lower pressure air from the central compressor room. This set-up can lower your costs significantly, starting with the reduction of high-pressure piping.

In a hybrid set-up, you don’t need many meters of expensive piping because the high-pressure air no longer has to come all the way from the compressor room. That alone can save you a lot of money. That’s because in most cases, high-pressure piping is made of stainless steel – and therefore very expensive. In fact, depending on where the compressor room is located, these high-pressure pipes may end up costing as much as or more than the PET air compressor itself!

In addition, the hybrid approach decreases your building costs, as you don’t need a large or second compressor room to house your booster.

Finally, by combining a booster with an Atlas Copco Variable Speed Drive (VSD) compressor, you can lower your energy expenses by up to 20%. In addition, a lower pressure drop in the compressed air system may also mean that you can manage with a smaller, less expensive compressor that uses less energy. And that will of course help you meet your environmental and sustainability goals.

Overall, you can greatly reduce your total cost of ownership with this hybrid PET bottle plant set-up.