The dew point of our heatless air dryer is -20℃, -40℃, etc. In addition, this regenerative air dryer is high pressure. The inlet air pressure can be 25 bar. Of course, we can also customize higher pressure adsorption compressed air dryer. Max air pressure reaches 100 bar.
What is heatless purge type air dryer for air compressor?
Heatless dryer is also pressure swing adsorption dryer. But it is different from heated regenerative desiccant air dryer. It utilizes the selective adsorption properties of desiccant beads. They can absorb moisture in compressed air. So as to achieve the purpose of drying. The adsorbent will reach saturation equilibrium in a certain time. Therefore, it is necessary to use dry air for regeneration. It’s to restore the adsorption and drying capacity.
Heatless desiccant dryer uses a portion of its own drying air. Then it’s depressurized to near atmospheric pressure. So it will regenerate the adsorbents as regeneration air. It perform two-tower switching with fixed time. Thereby, it can supply the dry air continuously.
Technical sheet of regenerative air dryer:
Why choose our air dryer for air compressor?
① Strict quality control
This adsorption dryer passes high pressure test with nitrogen. So it can keep the desiccant dryer safe. At the same time, we use high-quality brand adsorbents. The particle size is 3~5mm. Besides , it has good water resistance. Immersion in water will not crack or swell. In additon, we use the high quality control valves. Therefore, the failure rate of our adsorption air dryer is low.
② Reasonable structure design
There is the air distribution structure at the bottom of the twin towers. Compressed air enters the heatless desiccant air dryer. Firstly, they will slow down to spread. So ensure a uniform and smooth flow through desiccant beads. On the one hand, it can guarantee their contact time. So it reaches the dew point temperature. At the same time, it also reduces the impact of airflow on the adsorbent. Thus, it can improve the service life of the adsorbent.
③ Stable dew point, no fluctuation
Firstly, we use high-efficiency activated alumina. Secondly, regenerative air dryer adopts the 10min process cycle design. So it guarantee extremely low dew point. There is an adequate desiccant dose. We fill more desiccant beads than other heatless air dryer. So the outlet dew point is stable. And dryness is high.
④ Easy maintenance
There are feeding and discharging ports on the drying towers. So it’s easy for loading and unloading of desiccant beads. In addition, it uses thread or flange to connect the pipelines. Easy maintenance and disassembly.
How does a heatless desiccant air dryer work?
The heatless regenerative dryer uses the PSA principle. That is, the pressure swing adsorption. This is 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 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 humidity level. And achieve drying effect.
Afterwards, the dry air flows out through the C1 outlet valve. Part of dry air passes through the RT regeneration throttle valve. It is expanded to near atmospheric pressure. Then they enters tower B. This proportion of dry air is about 13%.
The dry air is also namely regenerative air. They gradually desorb water vapor from the adsorbent surface. So it can recover the ability of desiccant beads. The water vapor will be discharged to atmosphere through the V4 valve and the SF silencer. After regeneration of the B-tower, the V4 regeneration valve will close. The pressure will be gradually back 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
Adsorption air dryer includes heatless and micro heated regenerative dryer. Now we will introduce their differences.
① Working principles are different
The former bases on the principle of PSA and regeneration cycle. It carries out adsorption drying by self-heating. It requires no external heat source. But 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 valves switching is more frequent. Then the lifespan is relatively shorter;
② Different regeneration air consumption / loss
The air loss of former adsorption dryer is about 12~15%. However, the air loss of heat regeneration dryer is about 7%. So the latter is more energy-saving.
③ Different drying effects
The heat regenerative air dryer has better drying effect than heatless desiccant air dryer. Usually, the former dryer only uses alumina. But the latter will use alumina + molecular sieve.
Generally speaking, it is difficult 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℃.
Regenerative adsorption air dryer troubleshooting (1) The desiccant dryer can’t reach the design dew point
Below are the possible reasons:
① Inlet air flow of heatless desiccant air dryer is too large;
② The inlet air temperature is too high;
③ The inlet air pressure is too low;
④ Water content of the entrance is too large;
⑤ The regeneration air volume is too small;
⑥ The regeneration temperature is too low;
⑦ Silencer muffler is blocking;
⑧ Desiccant beads failure;
⑨ The dew point indication is not right;
How to solve the problems:
① Observe if the dryer capacity matches the air compressor;
② Check the front refrigerant air dryer. And lower the inlet air temperature;
③ Analyse if the actual air consumption is too big;
④ Check the refrigeration air dryer and pre-filter drain valve;
⑤ Adjust the regeneration air volume;
⑥ See #B (for micro-heat regeneration);
⑦ Change the silencer muffler with a new one;
⑧ Relief pressure for adsorption air dryer. And check the desiccant beads;
⑨ Recheck (when dew point meter is available);
(2) Heatless desiccant air dryer not purging
The possible reasons are as follows:
① It can’t start the adsorption air dryer;
② It is lower than the pneumatic valve control pressure;
③ There is damage to the five-way two-position pilot valve;
④ Not right adjustment of filter regulator;
Below are the solutions for reference:
① Fix the dryer control system or change it;
② The control pressure must be not too low. It needs be no less than 4.5 bar;
③ Replace and repair the valve in time;
④ Adjust the filter regulator to ensure pressure above 4.5 bar;
(3) The regenerative adsorpation air dryer has too big pressure drop
Below are some causes:
① The diffusers at the bottom of the drying tower are blocking;
② The actual air consumption of the terminal is too large;
③ Regeneration flow rate is too large. So the flow through the silencer muffler is too big;
④ Some valves are closed;
⑤ Desiccant beads clumping or chalking;
The corresponding measures are as follows:
① Replace the diffuser with a new one
② Check the pressure situation of the inlet air
③ Adjust or repair the valve in the heatless desiccant air dryer system
④ Check the air inlet valve and the outlet valve
⑤ Replace the desiccant beads
(4) There are too much air flow through the silencer muffler
Below are some reasons:
① One-way valve of the desiccant dryer leaks;
② The valve at the inlet of the dryer doesn’t switch;
③ Regeneration discharge valve keeps opening;
④ There is damage of five-way two-position pilot valve;
⑤ The diaphragm of the valve breaks;
How to solve these problems:
Fix or replace the valves or valve parts.
FAQ Q1: What is the function of muffler silencer in heatless adsorption dryer?
A1: 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 ~ 110dB. So the muffler can reduce noise.
These 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.
Q2: What is the function of the orifice of the regeneration valve?
A2: Heatless regenerative dryer uses its own dry air to desorb the adsorbent. These dry air passes through the regeneration valve and then enters the regeneration tower. The orifice has the following functions:
① Reduce the regeneration air pressure to near atmospheric pressure.
② Ensure that the water vapor can be discharged out of the tower smoothly.
Q3: How often should change the desiccant beads?
A3: The specific replacement cycle bases on actual usage. For example, in some harsh environments, the adsorbent change cycle will be shorter. If the environment is good and well maintained, the lifetime will be longer. Typically, we need to change the desiccant beads each two years.
Q4: How long is the drying twin towers switch cycle time?
A4: The switch cycle time of this heatless desiccant air dryer is about 20 minutes.
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