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Sahara Air Products

Latest News & FAQ's

What are two of the most common complaints about heat-of-compression dryers?

What if the compressor being used has a relatively low discharge temperature?

  1. There are times when the compressor discharge temperature is not hot enough for an acceptable dew point.
  2. There are times when the primary compressor is down and portable compressors are brought in rendering the dryers useless.

 

Now, SAHARA has improved the design and operation of the HC dryer to overcome these common objections.

Compressors selected for use with a heat-of-compression dryer often have a relatively low discharge temperature. This may happen all of the time, like some of the new 4-stage centrifugal compressors, or periodically during times of low load on the compressor. If this occurs with a conventional heat-of-compression dryer, then performance suffers. The outlet dew point of the dryer is directly related to the regeneration temperature. If, for whatever reason, the dryer doesn't see hot enough air, it simply can't deliver the specified dew point.

 

A new option available for the HC design heat-of-compression dryer overcomes this problem. A small booster heater on the stripping line will automatically energize as necessary to provide adequate regeneration temperatures. We still use the hot air from the compressor to provide the bulk of the energy necessary for regeneration. In fact, all of the hot air from the compressor directly regenerates the desiccant.

 

A temperature monitor at the inlet of the dryer can be adjusted to automatically energize the heater, if the temperature from the compressor is not sufficient. Another temperature monitor at the discharge of the regenerating tower will terminate regeneration and begin cooling of the desiccant. All of this is done automatically, without any operator attention. The dryer is controlled by a programmable controller with a touch screen monitor. All operations of the dryer are accessible through the monitor.

 

This new refinement allows the SAHARA HC dryer to provide the specified dew point, even during low flows and low temperatures from the compressor.

What if the primary compressor is down for maintenance or has a failure?

This is another serious problem. Obviously, compressed air must be supplied to the plant and often, when the primary compressor is down, portable or rental compressors are brought in to provide compressed air. Typically, oil-free portable rental compressors have built-in heat exchangers, so the discharge temperatures are much too low for a heat-of-compression dryer. The conventional heat-of-compression dryer must be bypassed and rental dryers brought in with the rental compressors.

 

The "heatless" mode of operation with the SAHARA HC heat-of-compression dryer overcomes this obstacle. Low temperature air from an oil-free portable compressor may be connected directly to the inlet of the HC dryer. By simply touching the touch screen monitor, the plant operator may switch from normal operation to "heatless" mode. In this mode of operation, the dryer will deliver the specified dew point.