Ponnusj:
I’ve designed, built, and operated adsorption dryers for air, CO2, Oxygen, Nitrous Oxide, and other gases to meet conditions of moisture content down to 1 ppm volume. What you are describing is nothing more than an adsorption dryer for compressed air that relies on the discharge temperature of the associated air compressor discharge temperature as the source of heat for regenerating the spent adsorber bed.
I agree with your suspicions that you can’t expect to save 75% of regeneration heat requirements with the proposed system design. In order to fully analyze the operation and calculate any energy consumption you have to first state the basic design, such as the very poor moisture removal, the need for more valves, the bigger adsorbent beds, and the required drop in pressure from the compressor discharge.
The pressure drop is a basic requirement in the flow diagram furnished by Breizh. This is not a result of the adsorbent bed solely. The basic pressure drop is a requirement in order to divert the hot compressor flow through regeneration and cooling and subsequently enter the drying adsorbent bed. The IR flow diagram doesn’t show this detail very well, so that need is not perceived.
Basically this system is adequate if you only need -40 F dew point – which isn’t very dry. And IR doesn’t tell us what compressor discharge temperature is required in order to achieve that dew point. The normal discharge temperature I would expect is approx. 225 F – which is not very hot considering it has to vaporize the captured water in the spent bed. A higher discharge temperature would mean a larger required compression ratio – which would mean more hp and more oil decomposition and adsorbent bed contamination. These factors would be trade-offs and might be acceptable. It all depends on what one needs, can afford, or tolerate. There are no free rides or free lunches in life.