Liquid air power and storage

Abstract

Apparatus, systems, and methods store energy by liquefying a gas such as air, for example, and then recover the energy by regasifying the liquid and combusting or otherwise reacting the gas with a fuel to drive a heat engine. The process of liquefying the gas may be powered with electric power from the grid, for example, and the heat engine may be used to generate electricity. Hence, in effect these apparatus, systems, and methods may provide for storing electric power from the grid and then subsequently delivering it back to the grid.

What is claimed is: 
     
         1 . A method of storing and recovering energy, the method comprising:
 regasifying liquid air or liquid air components to produce gaseous air or gaseous air components using heat from an exhaust gas stream from a turbine;   mixing a gaseous fuel and at least a portion of the gaseous air or gaseous air components to form a mixture and combusting the mixture to form a gaseous primary working fluid at an elevated temperature;   expanding the gaseous primary working fluid through the turbine; and   producing electricity with a generator driven by the turbine;   wherein regasifying the liquid air or liquid air components to produce the gaseous air or gaseous air components using heat from the exhaust gas stream from the turbine comprises:
 freezing carbon dioxide out of the exhaust gas stream by transferring heat from the exhaust gas stream to the liquid air or liquid air components to cool the turbine exhaust gas stream; 
 cooling a storage medium by transferring heat from the storage medium to the exhaust gas stream after freezing the carbon dioxide out of the exhaust gas stream; and 
 using the cooled storage medium as a heat sink during liquefaction of the liquid air or liquid air components. 
   
     
     
         2 . The method of  claim 1 , comprising producing the liquid air or liquid air components in an electrically powered liquefaction process and storing the liquid air or liquid air components for later regasification and use in combusting the gaseous fuel. 
     
     
         3 . The method of  claim 1 , wherein combusting the mixture of gaseous air or gaseous air components and fuel comprises combusting the mixture of gaseous air or gaseous air components and fuel catalytically. 
     
     
         4 . The method of  claim 1 , wherein the gaseous fuel is or comprises natural gas. 
     
     
         5 . The method of  claim 1 , comprising separately providing different ones of the gaseous air components to a combustor in which they are combusted with the fuel. 
     
     
         6 . The method of  claim 1 , comprising providing the gaseous primary working fluid to an inlet of the turbine at a temperature greater than or equal to 1600 K and a pressure greater than or equal to 30 bar. 
     
     
         7 . The method of  claim 1 , comprising cooling the turbine with a portion of the gaseous air or gaseous air components provided to the turbine separately from the gaseous primary working fluid. 
     
     
         8 . The method of  claim 1 , comprising heating a secondary working fluid with heat from the exhaust gas stream from the first turbine to convert the secondary working fluid from a liquid phase to a gas phase, and using the heated working fluid in a Rankine power cycle to generate additional electricity. 
     
     
         9 . The method of  claim 8  wherein the secondary working fluid is an organic working fluid, comprising regasifying the liquid air or liquid air components using heat transferred from the organic secondary working fluid to the liquid air or liquid air components, thereby condensing the organic secondary working fluid from a gas phase to a liquid phase. 
     
     
         10 . The method of  claim 8 , wherein the secondary working fluid is or comprises water. 
     
     
         11 . The method of  claim 1 , comprising heating water to produce superheated steam using heat from the exhaust gas stream from the first turbine, and mixing some or all of the superheated steam with the gaseous air or gaseous air components and gaseous fuel during combustion of the gaseous air or gaseous air components and gaseous fuel.