Apparatuses and methods for using residual heat in gas compression systems

Abstract

The present disclosed subject matter relates to energy efficiency improvements in compressed air systems and methods to implement them. According to an aspect of the present disclosure, improving the efficiency is performed by recovering the “wasted energy” in the compressed air and/or condensed water energy streams produced by the compressor and the cooling drying process.

1 . An apparatus for enhancing efficiency of an air compressor comprising:
 a pre-cooler though which ambient air is cooled before entering the compressor using a coolant fluid;   an after-cooler receiving compressed air from the compressor, wherein the compressed air is cooled;   an economizer for exchanging heat receiving a first stream of the compressed air from the after-cooler and a second stream from the pre-cooler, wherein the second stream is of heated air that was heated in the pre-cooler by exchanging heat with the ambient air, and wherein said economizer outlets a third stream of the compressed air heated by the first stream and a fourth stream of cooled air; and   a cooling dryer receiving the fourth stream from the economizer, configured to further cool the fourth stream and direct it to said pre-cooler, wherein said forth stream passed through the dryer acts as the coolant fluid,   wherein heat is exchanged in the pre-cooler and the economizer by residual heat.   
     
     
         2 . The apparatus for enhancing efficiency according to  claim 1 , wherein the pre-cooler cools the ambient air to approximately 9-11° C. 
     
     
         3 . The apparatus for enhancing efficiency according to  claim 1 , wherein energy that is used for cooling the ambient air in the pre-cooler is harvested from residual energy of the cooling dryer. 
     
     
         4 . The apparatus for enhancing efficiency according to  claim 1 , wherein the compressed air exiting the compressor and enters the after-cooler is cooled by a regulator. 
     
     
         5 . The apparatus for enhancing efficiency according to  claim 1 , wherein the cooling dryer is configured to reduce the compressed air temperature to a dew point of 2-3° C. that is used as the coolant. 
     
     
         6 . The apparatus for enhancing efficiency according to  claim 1 , wherein the after-cooler and the economizer are combined to a single unit. 
     
     
         7 . The apparatus for enhancing efficiency according to  claim 6 , wherein the single unit is regulated by a regulator selected from a group of a fan, a blower, a heat-sink, and any combination thereof. 
     
     
         8 . The apparatus for enhancing efficiency according to  claim 1 , wherein an auxiliary cooling unit is adjunct to the cooling dryer to facilitate cooling. 
     
     
         9 . The apparatus for enhancing efficiency according to  claim 1 , wherein the pre-cooler combined with the auxiliary cooling unit cools the ambient air to approximately 6° C. 
     
     
         10 . A method of using residual heat to increase efficiency of air compression process comprising:
 cooling the atmospheric air in a pre-cooler before entering the compression process using the compressed air from the compression process that is dried and cooled; and   heating an outlet stream from the compression process using residual heat that was taken from an after-cooler that receives the compressed air from the compression process.   
     
     
         11 . The method of using residual heat according to  claim 10 , further comprising cooling the compressed air that leaves the compressing process by a regulator. 
     
     
         12 . The method of using residual heat according to  claim 11 , the regulator is controlling a temperature in which the compressed air enters an economizer, wherein the economizer produces a stream of compressed air that is heated. 
     
     
         13 . The method of using residual heat according to  claim 10 , wherein cooling of the atmospheric air in a pre-cooler in about 13 degrees Celsius and heating the outlet stream from the compression process in about 9 degrees Celsius increases the efficiency of the compression process by about 7-9%. 
     
     
         14 . An apparatus for enhancing efficiency of an air compressor comprising:
 a pre-cooler through which ambient air is cooled before entering the compressor using a coolant fluid;   an after-cooler receiving compressed air from the compressor through a first economizer that is provided between the compressor and the after cooler for exchanging heat, wherein the compressed air from the compressor is cooled in the first economizer and further cools in the after-cooler;   a second economizer that receives compressed air from the after-cooler, wherein the compressed air from the after-cooler is further cooled in the second economizer and wherein the first economizer is receiving a first stream of the compressed air from the compressor and a second cooler stream from the second economizer;   an outlet of compressed air having a pre-determined temperature, wherein the pre-determined temperature is a result of a mixture of compressed air from the second economizer that pass through the first economizer with a first temperature and the compressed air from the second economizer having a second temperature;   a mixing valve receiving the compressed air from the second economizer and splitting the compressed air so as a first portion flows directly to the outlet with the second temperature and a second portion that flows to the outlet through the first economizer having the first temperature and wherein a predetermined temperature of the air in said outlet controls a ratio between the first portion and the second portion;   wherein the compressed air from the compressor that was cooled in the second economizer is directed to the evaporator and heated air from the pre-cooler is directed to the second economizer so as to reduce the compressed air temperature sent to the evaporator,   wherein heat is exchanged in the pre-cooler and the economizers by residual heat.   
     
     
         15 . The apparatus for enhancing efficiency of an air compressor as claimed in  claim 14 , wherein condensed water is collected from the cooling process in a cold condense tank. 
     
     
         16 . The apparatus for enhancing efficiency of an air compressor as claimed in  claim 15 , wherein the cold condense tank is provided with an exit valve having a flowrate that is controlled by the height of the condensed water in the cold condense tank. 
     
     
         17 . The apparatus for enhancing efficiency of an air compressor as claimed in  claim 15 , wherein the condensed water that exits the cold condense tank pass through the after cooler so as to cool the compressed air that passes through. 
     
     
         18 . The apparatus for enhancing efficiency of an air compressor as claimed in  claim 11 , wherein the mixing valve is controlled by a value of the predetermined temperature. 
     
     
         19 . The apparatus for enhancing efficiency of an air compressor as claimed in  claim 14 , wherein air from the pre-cooler passes through the evaporator.