In situ membrane-based oxygen enrichment for direct energy conversion methods

Abstract

A method for combusting a diesel or JP-8 fuel at high temperatures enabling efficiency and power density improvements for portable direct energy conversion systems such as thermophotovoltaics and thermionics is provided. Oxygen enriched air is processed in situ using membrane separation methods. A blower or pump downstream from the membrane provides oxygen enriched air to a fuel burner where high temperature oxidation of a diesel or JP-8 fuel is then enabled in a burner assembly. The hot combustion gases in the burner heat an emitter specifically designed for a thermophotovoltaic or thermionic device. A second blower or pump provides nitrogen enriched air for auxiliary cooling purposes.

1 . An apparatus for enabling efficiency and power density improvements for fueled portable direct energy conversion systems comprising: 
 a membrane separation apparatus used for increasing the oxygen volume content of intake air through membrane separation techniques:    permeate and feed pumps for providing a variable supply of oxygen-enriched air to a fuel burner apparatus;    a burner apparatus that atomizes fuel and burns said fuel with oxygen-enriched air to produce hot exhaust gases,    a combustion chamber/emitter assembly that contains and is heated by the hot combustion gases, and transfers energy; and    a feedback mechanism to control fuel flow as a function of load demand.    
   
   
       2 . The apparatus of  claim 1  wherein the permeate and feed pumps are downstream from the membrane.  
   
   
       3 . The apparatus of  claim 1  wherein the permeate and feed pumps are upstream from the membrane.  
   
   
       4 . The apparatus of  claim 1  wherein the fuel flow, air flow, and oxygen content is controllable.  
   
   
       5 . The apparatus of  claim 4  wherein an optimum emitter temperature is maintained by controlling the fuel flow, air flow, and oxygen content.  
   
   
       6 . The apparatus of  claim 4  wherein the oxygen content of intake air can be increased from 21% to 22-50%.  
   
   
       7 . The apparatus of  claim 6  wherein the oxygen content is established through a membrane separation means.  
   
   
       8 . The apparatus of  claim 1  wherein a nitrogen-enriched retentate flow is used for auxiliary cooling purposes.  
   
   
       9 . The apparatus of  claim 1  wherein the energy transfer takes place through a means selected from the group comprising thermophotovoltaic means or thermionic means.  
   
   
       10 . The apparatus of  claim 4  wherein the fuel and air flow are controlled to achieve a near stoichiometric mixture of fuel & air with an equivalence ratio of about 1.0.  
   
   
       11 . A method for enabling efficiency and power density improvements for fueled portable direct energy conversion systems comprising the steps of: 
 using a membrane separation apparatus for increasing the oxygen volume content of intake air through membrane separation techniques:    providing permeate and feed pumps for providing a variable supply of oxygen-enriched air to a fuel burner apparatus;    atomizing fuel with a burner apparatus that burns said fuel with oxygen-enriched air to produce hot exhaust gases,    providing a combustion chamber/emitter assembly that contains and is heated by the hot combustion gases, and transfers energy; and    controlling the fuel flow with a feedback mechanism such that fuel flow is controlled as a function of load demand.    
   
   
       12 . The method of  claim 11  wherein the permeate and feed pumps are downstream from the membrane.  
   
   
       13 . The method of  claim 11  wherein the permeate and feed pumps are upstream from the membrane.  
   
   
       14 . The method of  claim 11  wherein the fuel flow, air flow, and oxygen content is controllable.  
   
   
       15 . The method of  claim 14  wherein an optimum emitter temperature is maintained by controlling the fuel flow, air flow, and oxygen content.  
   
   
       16 . The method of  claim 14  wherein the oxygen content of intake air can be increased from 21% to 22-50%.  
   
   
       17 . The method of  claim 15  wherein the oxygen content is established through a membrane separation means.  
   
   
       18 . The method of  claim 11  wherein a nitrogen-enriched retentate flow is used for auxiliary cooling purposes.  
   
   
       19 . The method of  claim 11  wherein the energy transfer takes place through a means selected from the group comprising thermophotovoltaic means or thermionic means.  
   
   
       20 . The apparatus of  claim 14  wherein the fuel and air flow are controlled to achieve a near stoichiometric mixture of fuel & air with an equivalence ratio of about 1.0.