Modified and controlled atmosphere system and method

Abstract

The present disclosure relates to systems and methods for creating and maintaining modified and controlled atmospheres (MA/CA) in a rigid sealable container having at least one refrigeration unit with an integrated oxygen reduction structure. The refrigeration unit provides the necessary ambient atmosphere movement for the oxygen reduction structure, such as a hydrogen fuel cell. The systems and methods are useful in the, storage, transport, distribution, processing and packaging of fresh perishables with a focus on altering the natural gaseous environment around the perishables such that fresh shelf-life is extended. The systems may operate in a power generation/power production mode, such that the fuel cells maintain the MA/CA environment while providing both primary and back-up power.

What is claimed is: 
     
         1 . A method for extending the storage life of non-respiring foodstuffs comprising:
 generating and maintaining a modified and controlled atmosphere (MA/CA) environment in a mechanically refrigerated system within a rigid sealable container, the mechanically refrigerated system having at least one mechanical refrigeration unit, by:   generating a recirculating forced atmosphere stream within the rigid sealable container by operation of said mechanical refrigeration unit, the recirculating forced atmosphere stream being from the ambient atmosphere inside the rigid sealable container;   positioning an oxygen reduction means along the recirculating forced atmosphere stream within the container interior to reduce the amount of oxygen within the forced atmosphere stream; and   operating the oxygen reduction means on the recirculating forced atmosphere stream in an oxygen reduction mode to reduce the oxygen level to, and maintain the oxygen level at, 10,000 ppm or less inside the rigid sealable container.   
     
     
         2 . The method of  claim 1 , further comprising operating said oxygen reduction means to reduce the oxygen level inside said rigid, refrigerated container to 1000 ppm or less. 
     
     
         3 . The method of  claim 1 , further comprising operating said oxygen reduction means to reduce the oxygen level inside said rigid, refrigerated container to 1000 ppm or less in 72 hours or less. 
     
     
         4 . The method of  claim 1 , wherein operating the oxygen reduction means is carried out in an MA/CA environment comprising a CO2 level of 25-100%. 
     
     
         5 . The method of  claim 4 , wherein said operating the oxygen reduction means is carried out in an MA/CA environment comprising a CO2 level of greater than 90%. 
     
     
         6 . The method of  claim 1 , wherein said oxygen reduction means is selected from the group consisting of electrochemical means, catalytic means, chemical or biochemical means, mechanical means, pressure swing, and a combination thereof. 
     
     
         7 . The method of  claim 1 , wherein:
 the oxygen reduction means operating step is carried out:
 using one or more hydrogen powered fuel cells, each comprising an anode and a cathode; and 
 so that the recirculating forced atmosphere stream is directed across the one or more fuel cells where oxygen is reacted with hydrogen ions to form water, heat and electricity. 
   
     
     
         8 . The method of  claim 1 , wherein said rigid sealable container is selected from the group consisting of, a refrigerated shipping container, a refrigerated truck, a refrigerated rail car, a refrigerated break bulk ship hold, a refrigerated storage room, and a refrigerator. 
     
     
         9 . The method of  claim 1 , further comprising at least one of transportation and storage of non-respiring perishables in the rigid sealable container of said mechanically refrigerated system. 
     
     
         10 . The method of  claim 1 , wherein the system further comprises a controlled atmosphere unloading lock (CAUL) to facilitate periodic removal of perishable product, wherein the CAUL can maintain the following conditions: a CO2 concentration of above 25%, an O2 concentration of no more than 10,000 ppm, and a temperature-controlled environment. 
     
     
         11 . A modified and controlled atmosphere (MA/CA) system for use with non-respiring foodstuffs, comprising;
 a rigid sealable container defining a container interior capable of containing a supply of non-respiring foodstuffs within the container interior;   a mechanical refrigeration unit, having an air inlet and an air outlet, capable of generating a recirculating forced atmosphere stream from the container interior, through the mechanical refrigeration unit, and back into the container interior;   said rigid sealable container and said mechanical refrigeration unit constituting a refrigeration assembly;   an oxygen reduction means, positioned along the forced atmosphere stream within the container interior, for reducing the amount of oxygen within the forced atmosphere stream;   the oxygen reduction means comprising structure for retrofitting the container assembly; and   the oxygen reduction means capable of maintaining the oxygen level within the container interior at a level of 10,000 ppm or less.   
     
     
         12 . The system of  claim 11 , wherein oxygen reduction means is capable of maintaining the oxygen level within the container interior a level of 10,000 ppm or less with the CO2 level inside the container interior at 25-100% CO2. 
     
     
         13 . The system of  claim 11 , wherein said oxygen reduction means is capable of maintaining the oxygen level within the container interior at 1000 ppm or less. 
     
     
         14 . The system of  claim 11 , wherein oxygen reduction means is capable of maintaining the oxygen level within the container interior to 1000 ppm or less with the CO2 level inside the container interior 25-100% CO2. 
     
     
         15 . The system of  claim 11 , wherein said oxygen reduction means is selected from the group consisting of electrochemical means, chemical or biochemical means, mechanical means, catalytic means, pressure swing, and a combination thereof. 
     
     
         16 . The system of  claim 11 , wherein said oxygen reduction means comprises electrochemical oxygen reduction means is based on direct hydrogen powered fuel cell technology. 
     
     
         17 . The system of  claim 11 , wherein said oxygen reduction means comprises one or more hydrogen fuel cells, each fuel cell comprising an anode and a cathode, wherein the recirculating, forced atmosphere stream is directed across the one or more fuel cells with the anodes of said one or more fuel cells in communication with a hydrogen source, where oxygen is reacted with hydrogen ions to form water, heat and electricity. 
     
     
         18 . The system of  claim 17 , wherein at least one fuel cell is located internal to the rigid sealable container. 
     
     
         19 . The system of  claim 11 , wherein said rigid sealable container is selected from the group consisting of, a refrigerated shipping container, a refrigerated truck, a refrigerated rail car, a refrigerated break bulk ship hold, a refrigerated storage room, and a refrigerator. 
     
     
         20 . The system of  claim 11 , further comprising:
 a supply of perishable non-respiring foodstuffs within the container interior.