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Save Energy & Money with Efficient Plastic Dryers: Rotor Wheel Dryers, Vacuum Dryers, Throat Mounted Dryers
Excess moisture in plastic granules during processing can lead to a reduced quality of product, as well as potential machinery downtime.
Plastic dryers, are essential if you’re processing plastics – but your drying equipment may actually be costing you more than you think. Introducing the latest drying technology into your current processes can have a significant impact on your energy consumption, helping you bring down the cost of operation at a time when energy prices are rising…
Types of Plastic Polymer
The two types of plastic polymer discussed here are hygroscopic and non-hygroscopic polymers.
Consult your Material Data Sheet (MDS) for the drying specifications of your polymer type, including temperature and drying time as well as optimum final moisture content. With this in mind, you can find the right drying equipment to help you save energy and money on your existing processes.
Hygroscopic
Hygroscopic polymers refer to materials which absorb moisture from their environment, meaning the moisture penetrates the material. This includes:
- PET
- Nylon
- Acrylic
- Polyurethane
- ABS
- Polycarbonate
Their propensity for moisture absorption from the air means hygroscopic polymers will require drying as part of their processing.
Non-Hygroscopic
Non-hygroscopic polymers do not absorb moisture from their surrounding environment; however, they still may require drying due to moisture which collects on the surface of the material. If excess moisture is overlooked at this stage, the quality and efficiency of ongoing processes will be affected.
Examples of non-hygroscopic plastics include:
- PVC
- Polystyrene
- Polyethylene (PE)
- Polypropylene (PP)
In order to choose the correct size of dryer…
When choosing the right ancillary plastics drying equipment for your processes, the requirements of your polymer type will determine the equipment you use. For instance, desiccant and vacuum dryers are best for hygroscopic polymers, whilst hot air dryers are suitable for non-hygroscopic polymers.
You should also consider the size of dryer required, as well as the most suitable equipment type for your processes. Drying equipment should offer an appropriate throughput for your processes, which is determined by the capacity of the equipment.
Deciding on Plastics Drying Equipment
There are a few factors which could affect dryer size.
To choose the correct capacity, consider:
- Drying time
- Bulk density of the material
- Required airflow per kg of material to be dried
- The amount of material and throughput (kg/h)
Ensuring your equipment has sufficient capacity for the amount of material passing through, without wasting excess energy, is key to efficiency and energy savings.
Choosing the most suitable type of ancillary drying equipment for your processes also plays a factor in how efficient your processes can be. The most common types of dryers include…
Desiccant Dryer (Rotor Wheel Dryer)
The desiccant dryer, or rotor wheel dryer, is suitable for drying hygroscopic materials.
Desiccant dryers work by using an adsorbent desiccant material, which removes moisture from humid process air returning from the hopper. The dried air is then passed over the plastic pellets within the hopper, which draws moisture from them, leaving the plastic pellets dry and ready for further processing.
The desiccant material is further regenerated to dispose of the moisture into the atmosphere. within the system to reduce waste.
Summit Plastics Automation’s recommended VISMEC Drywell and Dryplus can be installed on, or used next to, the drying hopper, and can help to save 40% energy consumption when compared to traditional twin tower desiccant dryers.
Vacuum Dryer
Vacuum dryers are also suitable for hygroscopic materials with a high moisture content.
Unlike the rotor wheel dryer, vacuum dryers do not use a desiccant material to absorb moisture. Instead, a heating hopper is used to bring the material to the desired drying temperature, and then the material is dried by being placed under vacuum, which reduces boiling temperature and rapidly extracts the moisture in the material.
Vacuum dryers are an incredibly fast and efficient way of drying plastic, contributing to significant energy savings.
The Maguire ULTRA dryer, available through Summit Plastics Automation, is 6 times faster than conventional dryers, with 70% less energy consumption.
Compressed Air Dryers
Compressed air dryers are suitable for hygroscopic materials and work similarly to the rotor wheel dryer. The main difference between the two is the way in which air flow through the system is generated (compressed air vs mechanical blowers utilised in rotor wheel dryers).
With Summit Plastics Automation’s SDAC Series, air flow is automatically adjusted depending on throughput. The machine is also complete with an anti-stress function to prevent the over-drying of polymers, ensuring your processes are energy efficient with minimal waste.
The compressed air dryer is designed to be attached to the throat of smaller throughput machines, which is why the compressed air dryer may also be classified as a throat mounted dryer.
This compact and lightweight plastic dryer is designed for throughputs up to 50kg/h – a great energy-saving solution for smaller production volumes.
Hot Air Dryers
Hot air dryers are designed to dry non-hygroscopic polymers, and are available as a throat mounted dryer or as a free-standing unit to account for smaller and larger production volumes alike.
Summit Plastic Automation’s SHAD Series is available for airflow rates from 70-200m³/h and from 200-1350m³/h.
Hot air dryers circulate heated ambient air around drying hoppers by means of electric blowers, which evaporates any surface moisture from the polymers. The wet air is then dissipated into the atmosphere. Hot air dryers can also be used to pre-heat plastic in instances where the plastic has been stored in cooler environments, making certain that your polymers are ready for processing.
This highly insulated dryer ensures your drying hopper is working at a more efficient rate for energy and cost savings.
Expanding your processes with ancillary energy efficient plastic dryers can be the solution to reducing the energy consumption and soaring energy costs of your processes.
Ancillary equipment such as rotor wheel dryers, vacuum dryers, compressed air dryers, and hot air dryers can be installed as part of your current processes to streamline production: avoiding excess energy usage and reducing waste.
Make an informed decision by calculating your plastic drying requirements to invest