Air Drying and Its Applications
Air drying is the process of removing all moisture from the air. Moisture tends to build up in machinery, equipment, and computers. This build-up hampers the functionality of the machines and decreases their longevity by damaging the internal electrical components. As a rule, where there are electrical components involved, water or moisture must be kept out. There is an entire industry dedicated to the protection of electrical circuits and wiring fro, water.
This includes electrical and console enclosures, protective wiring covers, and air dryers which are most pertinent to this article. Air drying can be done through several techniques. Research and development projects aim to improve air drying techniques. The goal is to make them energy efficient as well as low cost. Let us take a look at some of the most common methods of air drying.
Air Drying Methods
Refrigeration Drying
In refrigeration dryers, hot air is pumped into the refrigerator through a tube encased in another tube. The outer tube has cool air blowing through it which cools down the hot air pumping through the inner tube. The air is then cooled almost to 0 degrees celsius. This allows almost all the moisture in the air to be compressed. The moisture collected at the bottom is removed through an automatic drain pipe. The air is then pumped into heat exchangers that remove any heat from the compressed air.
Finally, the air is passed through another heat exchanger, and the cooled dry air is heated back up. This allows the air to be more efficient in practical use. This sort of method is recommended because, after the initial investment, the maintenance cost is quite low.
Aftercooling
Aftercooling uses the principles of conduction, convection, and radiation in heat transfer to cool down compressed air. Any moisture in the compressed air is cooled down and condensed. The condensed liquid is then collected and separated, leaving the compressed air dry. Aftercoolers come as Air-cooled or water-cooled. Aftercoolers are quite easily available and do not require any electricity to run. However, water-cooled air coolers require a large volume of water making them inefficient.
Storage Tank Coolers
These are usually used in combination with aftercoolers. Air from the aftercoolers is bumped into a steel storage tank. This tank is kept at an extremely low temperature. As soon as the compressed air comes into contact with the cool metal walls of the storage tank, any leftover moisture is condensed out of the air. The water droplets that collect at the base of the tank must be collected after every use of the tank. This prevents water from freezing or the tank from becoming rusty. The storage tanks are cheap, easily available, and the process is quite simple. However, these tanks tend to be very large and require a lot of storage space. They are not very efficient methods of air drying either.
Molecular Sieves
The process of air drying using molecular sieves is relatively simple. Activated alumina traps any moisture present when air passes through it. Products like Jalon zeolite molecular sieve are developed to have a high capacity to trap water when humidity levels in the air are high. The molecular structure of these sieves stays stable even in extreme conditions. This allows for greater longevity for the product. Additionally, molecular sieves trap dust particles in the air as well.
They also have the ability to withstand high pressure, so more air can be pushed through at a time. This allows for time-efficient use of the sieve.
Uses of Dry Air
Food Industry
The basic aim while drying out moisture from packaging in the food industry is to increase the shelf life of food. Bacteria tend to grow and thrive in moisture. Moist and warm conditions are optimum for bacteria to reproduce. Wet food products have a shorter shelf life. This is why dry products are filled with dry air. This ensures that they do not rot.
Pharmaceutical Industry
It is absolutely vital to keep medicine under optimum conditions. A person’s life can depend on it. The composition of most pharmaceutical products is such that a slight presence of moisture can cause physical and enzymic deterioration. It can allow for different microbes to feed on the contents of the product. These microbes can be possibly harmful to anyone who ingests the medicine. Every step of the way, manufacturers need to make use of dry air to prevent any moisture from entering.
Warehouses and Computer Storage
The warehouses that store a massive amount of products for either the food industry or a manufacturer that sells electrical appliances need air dryers. This is because food, as mentioned before, can rot in moisture quicker. And moisture tends to damage electrical components over a long period of time. These damaged products will not be sale-worthy if they are damaged by even the slightest moisture.
Greenhouses
Greenhouses’ conditions are controlled strictly. Especially if the greenhouses house genetically engineered crops and plants. Every minute fluctuation in the physical conditions is detected and adjusted. The humidity level is also kept constant. Any fluctuations have to be rectified. If sensors detect high humidity, air dryers are required to bring it back to optimum levels.
Conclusion
Research and experimentation are constantly optimizing the process of air-drying. New technologies are being incorporated into the process to make it more time and cost-efficient. There is also the most important factor of ‘green’ production processes. Work and experimentation should be done to make this process as sustainable as possible. Renewable energy sources should be incorporated into the processes to make then environment friendly.
