Freeze dryer and adsorption dryer are both equipment used to remove moisture from compressed air. It can be seen that they are named after their respective working principles.
1. Principle difference
The working principle of Freeze dryer: 1. The moist compressed air enters the heat exchanger and exchanges heat with the refrigerant, causing the temperature of the compressed air to drop significantly. The lower the temperature, the less moisture the compressed air can carry. At low temperatures, it exceeds the amount of moisture that the compressed air can carry. The moisture in the air will condense into water droplets, and the compressed air will reach a saturated state. The low temperature that can be achieved during this period of cooling is the pressure dew point reached by the Freeze dryer when processing compressed air under this working condition.
2. The compressed air enters the air-water separator, and the condensed water is separated and discharged from the freeze dryer through the drain valve.
3. The compressed air enters the heat exchanger for the second time and exchanges heat with the hot compressed air that has just entered the Freeze dryer to reheat the compressed air, thereby making the temperature of the compressed air higher than the pressure dew point.
4. Discharge the processed dry compressed air.
The working principle of the adsorption dryer: 1. Compressed air enters the adsorption tower, and the moisture in the compressed air will be adsorbed by the adsorbent (usually the most commonly used activated alumina) filled in the adsorption tower.
2. Exhaust most of the processed dry compressed air.
3. A small part of the dried compressed air passes through the shut-off valve or enters the heater (slightly hot) before entering another adsorption tower to regenerate the adsorbent and restore the drying capacity of the adsorbent. This part of the compressed air is called To regeneration air.
4. The two adsorption towers are used alternately according to the set conditions.
2. What are the differences between its besides working principles?
1. The difference in dryness of the treated air. Freeze dryer due to the limitations of freezing point,Refrigeration heat exchange efficiency and gas-water separator separation efficiency limitations, Achievable pressure dew point is higher.The pressure dew point range that the Freeze dryer can reach is 2°C-10°C.Adsorption dryers can choose to use adsorbents with various properties, and can achieve lower pressure dew points. The pressure dew point range that the adsorption dryer can reach is -20°C~-70°C.
2.Differences in compressed air intake requirements.Freeze dryers can withstand higher inlet air temperatures and higher air inlet pressures, but high temperatures will also significantly reduce the drying effect of the freeze dryer. For more demanding working conditions, the freeze dryer should be appropriately enlarged freeze dryer processing capacity
when selecting.
Adsorption dryers have higher requirements for the cleanliness of compressed air. The oil molecules in the compressed air will block the adsorbent, causing irregenerable loss of the adsorbent. It will also affect the effect of adsorption drying.
3.Energy consumption difference.The heatless adsorption dryer has the lowest energy consumption; the freeze dryer has a built-in refrigeration compressor and the equipment has medium energy consumption; the microthermal adsorption dryer has a built-in heater and the equipment has high energy consumption.However, the heatless adsorption dryer consumes more regeneration air than the microthermal adsorption dryer. Looking at the entire unit, the overall energy efficiency of the microthermal adsorption dryer is better.
4.Maintenance differences.Adsorption dryers require regular replacement of adsorbents and maintenance of worn valves. The Freeze dryer requires no consumables, just clean the drain valve regularly.
5.Noise difference.The Freeze dryer has low noise and is basically silent in the operating environment of the air compressor. The adsorption dryer needs to discharge the regeneration air and makes a lot of noise, which is slightly less than that of the air compressor.
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