Is the compressed air dew point as low as possible

What is dew point? What is pressure dew point?

If the partial pressure of water vapor remains constant (ie the absolute water content remains constant). As the temperature drops below the dew point, condensed water droplets settle in the moist air. The dew point of humid air is not only related to the temperature, but also related to the moisture content in the humid air. The dew point is higher if there is more moisture, and the dew point is lower if there is less moisture. When moist air is compressed, the density of water vapor increases and so does its temperature. When the compressed air cools, the relative humidity rises. When the temperature continues to drop and the relative humidity reaches 100%, water droplets are precipitated from the compressed air. The temperature at this time is the pressure dew point of the compressed air.

compressed air dew point

What is the relationship between pressure dew point and atmospheric dew point?

The correspondence between the pressure dew point and the atmospheric dew point is related to the compression ratio. Even if the pressure dew point is the same, the higher the compression ratio, the lower the atmospheric dew point. Example: The compressed air pressure dew point of 0.7Mpa is 2°C, and the corresponding normal pressure dew point is -28°C.

What is used to measure dew point?

The unit of pressure dew point is °C, but its meaning is the moisture content in the compressed air. So measuring the dew point is actually measuring the moisture content in the air. There are many instruments for measuring the dew point of compressed air, such as a mirror dew point meter using nitrogen or ether as a cold source, a point solution hygrometer using phosphorus pentoxide or lithium chloride as an electrolyte, etc. Specialty gas dew point meters are now widely used in industry to measure the dew point of compressed air. Use a dew point meter to measure the pressure dew point of the compressed air. The sampling point should be placed in the exhaust pipe of the dryer. There should be no liquid water droplets in the sample gas, and there should be errors in the dew point.

In any case, don't think that the dew point of compressed air is as low as possible. This is the basic concept of scientific and reasonable selection of compressed air dryer equipment.

Because compressed air drying is the most costly process in the entire air compression system - the energy consumption paid in one year may exceed the purchase cost of the entire set of equipment, so it must be discarded when choosing a dryer. The lower the dew point, the better.

Facts have proved that in most industrial places, as long as the compressed air is processed by a freeze dryer, the compressed air can meet its dew point requirements: and in the case of the same gas volume, the energy consumption of the freeze dryer is only 1/5 of that of the adsorption dryer . Desiccant dryers should only be considered when the process dictates the use of dry compressed air. When choosing an adsorption dryer, the regeneration energy consumption should be evaluated in advance - through "energy balance" not only can accurately predict the amount of regeneration energy consumption, but also can find out the ins and outs of regeneration energy and find out further energy saving way of consumption.

At present, it is internationally recognized that the heatless regenerative adsorption desiccant dryer based on pressure swing adsorption is the first choice equipment for obtaining extremely dry compressed air, because there is no redundant energy loss link in the regeneration process. But even so, the gas consumption of "one part of the pressure" during regeneration makes it a large energy consumer in the gas source purification system.

Lingyu Machinery ~ low dew point regenerative desiccant compressed air dryer