The Moisture Trap is a piece of equipment that removes silt and condensate from “wet” gas just downstream of the digester. Condensate is a common by-product that occurs in the pipeline when the hot, saturated biogas cools. This prevents corrosion, obstruction, and water hammer in downstream equipment, allowing the gas train to function for years with little pressure decrease. Moisture trap filter removes water from fuel cell exhaust streams automatically. The moisture trap prevents back pressure regulators from flooding and allows water to be recirculated into the humidifier’s water supply vessel. The moisture trap can run unsupervised for a long period of time.


How does a Moisture Trap Work?

The incoming gas enters through the inlet and is permitted to circulate freely inside the baffled chamber. A centrifugal force and a dramatic reduction in velocity are created by the input nozzle. The bulk of silt and condensate are effectively removed from the wet gas by this combination of forces.

A baffle separator is made up of many baffle plates that force the flow to shift direction multiple times as it goes through the separator body. Because the suspended water droplets have a higher mass and inertia than the gas, when the flow direction changes, the dry gas travels around the baffles while the water droplets concentrate on them. Furthermore, because the separator has a high cross-sectional area, the fluid’s speed is reduced as a result. The kinetic energy of the water droplets is reduced, and the majority of them will fall out of suspension. The condensate gathers at the bottom of the separator and is automatically or manually drained away.


Causes of Moisture in Compressed Air

Compressed air produces moisture as a byproduct. A certain quantity of water vapour is present in every air. Temperature and pressure affect the amount of water that air can retain; the greater the temperature, the more water air can store. As a result, humidity levels are higher in the summer than in the winter. An air compressor compresses air under high pressure into a smaller volume. When air is drawn in by a compressor, it is compressed to roughly 12 times its typical atmospheric pressure. Water can’t hold as much in pressurised air. Water vapour condenses back into a liquid when pressure rises. Because the water in the air has to go somewhere, it forms condensate in the air compressor system.

Condensate can form in the receiver tank of the air compressor, as well as in the lines and other system components. Moisture may be drawn back into the compressed air stream if water is allowed to build. Condensation is a concern for compressed air systems throughout the year, but hot, humid air in the summer may result in enormous amounts of surplus water being produced. Cold temperatures in the winter, on the other hand, can limit evaporation efficiency, causing moisture to collect over time even when humidity is low. In order to avoid difficulties, excess air compressor moisture must be removed from your air compression system at all times.


Problems that occur due to moisture in air compressors

Water in compressed air systems can cause a variety of issues for your system. Water hammering can occur when there is too much water, causing damage to equipment and infrastructure which causes a knocking sound in the air compressor pipes. Liquid water can also clog control lines, preventing instruments from correctly reading and acting. Ice can build inside the system in freezing weather. Ice can clog filters and block input or outflow valves, causing the system to malfunction. Ice formation can damage pipes and other system components because water expands when it freezes.

Excess moisture in the compressed air stream can also be a major issue. Liquid water or excessive humidity in the compressed air stream might cause air tool corrosion or interfere with appropriate lubrication which is why a proper humidity filter is always required. Particulate from rust in air supply lines can mix with the air stream, causing equipment damage or fouling manufacturing operations. Water can have undesirable aesthetic and textural impacts on the finish when spray painting with a compressor. Pneumatic tools, CNC machining centres, robotics, air cylinders, and valve operation are some of the additional applications where moisture in air compressors is a major pain.


Removing water from compressed air


  • By draining the air receiver Tank

The first stage in your moisture-control strategy is to make sure that surplus water is regularly evacuated from the air compression system. A manual drain valve is the simplest way to achieve this. If manually draining, water should be emptied at least once daily. Draining the receiver tank is no longer necessary thanks to automatic timer-based and pneumatic drain valves. On a regular timetable or in reaction to a sensor, an auto drain valve will open to discharge surplus liquid.


  • Using a water separator filter

Mechanical separation is the next stage of moisture removal for your air compression system. A water separating filter is used for this (also known as a filtration water separator). These devices resemble an in-line air filter or an oil separator for an air compressor. With centrifugal force, the filter eliminates considerable amounts of moisture from the air supply.


  • Using refrigerated air dryers

If further removal is required, refrigerated air dryers are utilised. Chilling the air is how these dryers function. It’s important to remember that cooler air carries less moisture than warmer air. The chilled air drier cools pressurised air at around 33-40 degrees Fahrenheit. Excess water vapour condenses back into a liquid when the air cools. A water trap catches the liquid, which is then drained by an automated drain valve.


  • Using Desiccant Air dryers

For applications that demand highly dry compressed air, desiccant air dryers are used. These dryers use a chemical technique to remove water from the air. A desiccant is a material that forms a connection with water through chemical reactions. Activated alumina or molecular sieve desiccants are used in most desiccant air dryers.