Influencing factors of air consumption for heatless regeneration of Adsorption dryer

　　The Adsorption dryer uses the micropores of the desiccant material itself to absorb water molecules in the air according to capillary action, and at the same time remove the adsorbed water according to the pressure relief desorption and the heat of adsorption. The equipment is generally made into a double-cylinder form. Under the control of the program controller, the two cylinders work alternately, one cylinder absorbs water, and the other cylinder desorbs and regenerates, working continuously in cycles.
　　Due to the front of the refrigerated dryer, the moisture load of the Adsorption dryer is very small. When the inlet temperature is 2℃, the moisture load is only about 10% of that without the front of the refrigerated dryer (the inlet temperature is 38℃). When the inlet temperature is 10℃, the moisture load is less than 20%. Therefore, theoretically, it is completely credible that the non-thermal regeneration air consumption of the Adsorption dryer is about 3% to 5%. But how to achieve this attractive low energy consumption level is not a very easy task. Because it is also restricted by many factors.
　　1. Whether the adsorbent regeneration method is non-thermal regeneration or heating regeneration
　　If the adsorption and drying part of the combined unit adopts heatless regeneration based on pure "pressure swing adsorption" (PSA), the regeneration temperature should not be too low, otherwise the phenomenon of "low temperature desorption" will occur, which will cause "incomplete regeneration" to the adsorbent. And early deterioration and other adverse effects:
　　Therefore, some units heat the regeneration gas with "slight heat" on the basis of PSA. Although some additional heat energy is consumed, the regeneration conditions will be better. However, in terms of energy-saving (saving) effect, no matter whether heatless regeneration or "slight heat" regeneration is adopted, the important factor affecting air consumption is the control method of the regeneration system.
　　2. How to control the regeneration air volume
　　How to control the regeneration air volume? I often see expressions such as "extract a few percent of the regeneration air from the air outlet of the dryer". Such expressions are like "making the exhaust temperature of the refrigerated dryer close to the intake temperature". It seems easy to say. But the feasibility of actual operation (at least in terms of technical accuracy) is very questionable. It is much more difficult to extract a few percent of the compressed air flow "quantitatively" from the main pipeline than to scoop water quantitatively from a water tank. As a system, the regeneration gas enters the regeneration tower after depressurizing through the "throttle orifice".
　　The throttling orifice plays the following key roles in regulating the regeneration air volume:
　　(1) Reduce the regeneration air pressure to the required value-close to atmospheric pressure, the purpose is to reduce the regeneration air consumption as much as possible;
　　(2) Keep the regeneration air pressure at a low value-this pressure must at least ensure that the desorbed water vapor can overcome the resistance of the adsorption bed and exit the tower smoothly;
　　(3) It must be ensured that a certain amount of regeneration gas continuously flows through the adsorption bed within the set time—and at the off-tower temperature, the amount of regeneration gas must at least ensure that its water content is close to saturation.