Air compressor dryer equipment Cold dryer technical questions and answers

1. What are the characteristics of domestic cold dryers compared with imported cold dryers?

At present, the hardware configuration of domestic cold dryers is not much different from that of foreign imported machines. Refrigeration compressors, refrigeration accessories and refrigerants all use a large number of international famous brands.

The user applicability of cold dryers generally exceeds that of imported machines. This is because domestic manufacturers have fully considered the characteristics of domestic users, especially the climatic conditions and daily maintenance characteristics, when designing and manufacturing cold dryers.

For example, the power of refrigeration compressors of domestically produced cold dryers is generally larger than that of imported machines of the same specification, which fully adapts to the characteristics of my country’s vast territory and large temperature differences between regions/different seasons.

In addition, domestic machines are quite competitive in price, and have incomparable advantages in after-sales service. Therefore, domestic cold dryers are quite popular in the domestic market.

At present, the gap between domestic cold dryers and imported cold dryers is mainly reflected in the production process level, especially in the cleaning of refrigerant system pipelines, assembly and welding. In addition, imported green refrigerant R134a, which has no damaging effect on the atmospheric ozone layer, is now commonly used, which is still difficult to do in domestic cold dryers.

2. What are the characteristics of the cold dryer compared with the adsorption dryer?

Compared with adsorption drying, freeze dryer has the following characteristics:

① There is no gas source consumption. For most gas source users, using a cold dryer saves energy compared to using an adsorption dryer;

② No wear of valve parts;

③ No need to add or replace the adsorbent regularly;

④Low running noise;

⑤ The daily maintenance is relatively simple, as long as the automatic drain filter is cleaned on time;

⑥ There are no special requirements for the pre-treatment of the air source and the supporting air compressor, and the general oil-water separator can meet the air quality requirements of the cold dryer;

⑦The cold dryer has a “self-cleaning” effect on the exhaust, that is, the solid impurity content in the exhaust gas is less;

⑧ While discharging the condensed water, part of the oil vapor can also be condensed into liquid oil mist and discharged with the condensed water.

Compared with the adsorption dryer, the “pressure dew point” of the compressed air treatment of the cold dryer can only reach about 10°C, so the drying depth of the gas is far less than that of the adsorption dryer. The machine cannot meet the requirements of the process for the dryness of the air source. A selection practice has been formed in the technical circles: when the “pressure dew point” is required to be above zero, the air dryer is the first choice. When the “pressure dew point” is required to be below zero, the adsorption dryer is the only choice.

3. How to obtain compressed air with extremely low dew point?

The dew point of compressed air after being treated by a cold dryer can be around -20°C (atmospheric pressure), and the dew point can reach above -60°C after being treated by an adsorption dryer. However, it is obviously not enough for some industries that require extremely high air dryness (such as the microelectronics industry requires a dew point of -80°C). The method currently being promoted by the technical circles is to connect the cold dryer and the adsorption dryer in series, and use the cold dryer as the pre-treatment equipment of the adsorption dryer, so that the moisture content of the compressed air is greatly reduced before entering the adsorption dryer. Obtain compressed air with an extremely low dew point. Moreover, the lower the temperature of the compressed air entering the adsorption dryer, the lower the final dew point of the compressed air will be. According to foreign data, when the inlet temperature of the adsorption dryer is 2°C, molecular sieve is used as the adsorbent, and the dew point of the compressed air can reach below -100°C. This method has also been widely used in the country.

4. What should be paid attention to when the cold dryer is matched with the piston air compressor?

The dew point of compressed air after being treated by a cold dryer can be around -20°C (atmospheric pressure), and the dew point can reach above -60°C after being treated by an adsorption dryer. However, it is obviously not enough for some industries that require extremely high air dryness (such as the microelectronics industry requires a dew point of -80°C). The method currently being promoted by the technical circles is to connect the cold dryer and the adsorption dryer in series, and use the cold dryer as the pre-treatment equipment of the adsorption dryer, so that the moisture content of the compressed air is greatly reduced before entering the adsorption dryer. Obtain compressed air with an extremely low dew point. Moreover, the lower the temperature of the compressed air entering the adsorption dryer, the lower the final dew point of the compressed air will be. According to foreign data, when the inlet temperature of the adsorption dryer is 2°C, molecular sieve is used as the adsorbent, and the dew point of the compressed air can reach below -100°C. This method has also been widely used in the country.