Technical Sheet of Air Desiccant Dryer
|Product name||heatless purge type dryer|
|Inlet air capacity||Std.2.5 Nm3 / min | 150 Nm3 / Hr|
|Working principle||PSA pressure swing adsorption regeneration|
|Working period||≈20 min|
|Average regeneration air consumption||Std.10% | Min. 6% Max.12%|
|Inlet air pressure||20～30 bar|
|Air pressure loss at full load||0.2 bar|
|Inlet air oil requirements||Oil-free compressed air or ≤0.1ppm (mg/m3)|
|Inlet air temperature||10～30℃ | Min.2℃ Max.40℃|
|Dew point||(-20～-50℃ Ensure 100%)|
|Ambient temperature||Min.2℃ Max.45℃|
|Heatless type air dryer weight||150 Kg|
|Desiccant dryer size||726×630×1802 mm|
What is Heatless Purge Type Air Dryer For Air Compressor
The heatless dryer is also a pressure swing adsorption dryer. But it is different from a heated regenerative desiccant air dryer. It utilizes the selective adsorption properties of desiccant beads. They can absorb moisture in compressed air. To achieve the purpose of drying. The adsorbent will reach saturation equilibrium at a certain time. Therefore, it is necessary to use dry air for regeneration. It’s to restore the adsorption and drying capacity.
The heatless desiccant dryer uses a portion of its drying air. Then, it’s depressurized to near atmospheric pressure. So, it will regenerate the adsorbents as regeneration air. It performs two-tower switching with fixed time. Thereby, it can supply the dry air continuously.
How Does A Heatless Desiccant Air Dryer Work?
The heatless regenerative dryer uses the PSA principle. That is the pressure swing adsorption. This is a heatless regeneration method. It is to dry compressed air by circulating adsorption through twin towers. One tower adsorbs the moisture at a certain pressure. The other tower uses a small amount of dry compressed air. Then, it starts regeneration under reduced pressure. The two towers switch each other. So, it enables continuous adsorption and purification.
Wet air enters the heatless desiccant air dryer. Firstly, they enter tower A through the V1 inlet valve. The air flows from bottom to top along the adsorbent. So, it will gradually reduce the humidity level. And achieve a drying effect.
Afterward, the dry air flows out through the C1 outlet valve. Part of the dry air passes through the RT regeneration throttle valve. It is expanded to near atmospheric pressure. Then, they enter Tower B. This proportion of dry air is about 13%.
Dry air is also regenerative air. They gradually desorb water vapor from the adsorbent surface. So it can recover the ability of desiccant beads. The vapor will be discharged into the atmosphere through the V4 valve and the SF silencer. After regeneration of the B-tower, the V4 regeneration valve will close. The pressure will gradually return to the working pressure (approx. 7 bar).
At this time, the B-tower V2 inlet valve opens. And the B-tower enters the adsorption process. At the same time, V1 closes. And the V3 regeneration valve opens. The regeneration takes place. This cycle will switch to achieve continuous adsorption operation.
Heatless vs Heated Air Dryer
The adsorption air dryer includes a heatless and micro-heated regenerative dryer. Now, we will introduce their differences.
① Different Working Principles
The former is based on the principle of PSA and the regeneration cycle. It carries out adsorption drying by self-heating. It requires no external heat source. However, the latter combines the principles of PSA, temperature swing adsorption, and regeneration cycle. It carries out adsorption drying with external electric heating.
In addition, the heatless regenerative dryer has shorter adsorption cycle. So, valve switching is more frequent. Then, the lifespan is relatively shorter.
② Different Regeneration Air Consumption/Loss
The air loss of the former adsorption dryer is about 12~15%. However, the air loss of the heat regeneration dryer is about 7%. So the latter is more energy-saving.
③ Different Drying Effects
The heat regenerative air dryer has a better drying effect than a heatless desiccant air dryer. Usually, the former dryer only uses alumina. But the latter will use an alumina + molecular sieve.
Generally speaking, it isn’t easy to achieve deep regeneration for heatless dryer. The dew point is generally -20 to -40°C. But the micro heat regenerative dryer can deeply remove water. The dew point can reach -70℃.
The heatless desiccant dryer discharges the regeneration air. So it will make noise. The regeneration exhaust air has a certain pressure when it is discharged. Besides, exhaust speed is fast. So it can cause air vibrations. And produce strong exhaust noise. Generally, it can reach 80 ~ 110 dB. So the muffler can reduce noise.
This air will carry a lot of dust and moisture. Condensation will build up. It is easy to cause the muffler to clog. So pay attention to timely replacement.
A heatless regenerative dryer uses its own dry air to desorb the adsorbent. This dry air passes through the regeneration valve and enters the tower. The orifice has the following functions:
- Reduce the regeneration air pressure to near atmospheric pressure.
- Ensure that the water vapor can be discharged out of the tower smoothly.
The specific replacement cycle based on actual usage. For example, the adsorbent change cycle will be shorter in some harsh environments. The lifetime will be longer if the environment is good and well-maintained. Typically, we need to change the desiccant beads every two years.
The switch cycle time of this heatless desiccant air dryer is about 20 minutes.