Method and Apparatus for Extracting Frozen Volatiles from Subsurface Regolith

Abstract

A volatile extraction well and method to utilize heat, which could be from the sun or from some other energy source, to directly vaporize subsurface water-ice, or other frozen volatile substance, in-situ. The pressure of the vaporized water (or other volatile gas) released in the heated soil causes the vapor to flow into a sealed drill-hole, or well, and on through an extraction tube to a surface collection vessel where it is condensed and stored.

1 . A volatile extraction well for extracting a frozen subsurface volatile substance from soil or regolith, comprising:
 a borehole drilled into the soil or regolith;   a heating element inserted in the borehole at a depth where the volatile substance is to be extracted and capable of radiating or conducting sufficient thermal energy to the soil or regolith to vaporize the frozen volatile substance;   a gas seal formed at or near the top of the borehole to prevent uncontrolled escape of vapor from the borehole when released by the heating element;   an extraction tube or conduit extending through the gas seal for removing vapor from the borehole when released by the heating element.   
     
     
         2 . The well of  claim 1  wherein the borehole is substantially vertical or tilted at an angle to the vertical. 
     
     
         3 . The well of  claim 1  wherein the borehole is curved. 
     
     
         4 . The well of  claim 3  further comprising a plurality of substantially horizontal boreholes extending from the bottom of the curved borehole. 
     
     
         5 . The well of  claim 1  wherein the heating element is self-contained within the borehole. 
     
     
         6 . The well of  claim 1  further comprising a surface mounted energy source and a conduit or cable extending through the gas seal to the heating element to connect the heating element to the surface mounted energy source. 
     
     
         7 . The well of  claim 6  wherein the surface mounted energy source is solar powered. 
     
     
         8 . The well of  claim 1  further comprising a surface located collector and condensor connected to the borehole through the extraction tube or conduit for collecting and condensing vapor from the borehole when released by the heating element. 
     
     
         9 . The well of  claim 8  wherein the collector and condensor maintains a sufficiently low pressure in the borehole to allow vapor released by the heating element to flow to the collector and condensor. 
     
     
         10 . The well of  claim 9  wherein the collector and condensor maintains the pressure in the borehole below the boiling pressure of the volatile substance being recovered, corresponding to the temperature of the heated subsurface region of the well. 
     
     
         11 . A method for extracting a frozen subsurface volatile substance from soil or regolith, comprising:
 drilling a borehole into the soil or regolith;   inserting a heating element in the borehole at a depth where the volatile substance is to be extracted, the heating element being capable of radiating or conducting sufficient thermal energy to the soil or regolith to vaporize the frozen volatile substance;   forming a gas seal at or near the top of the borehole to prevent uncontrolled escape of vapor from the borehole when released by the heating element;   providing an extraction tube or conduit extending through the gas seal for removing vapor from the borehole when released by the heating element.   
     
     
         12 . The method of  claim 11  wherein the borehole is substantially vertical or tilted at an angle to the vertical. 
     
     
         13 . The method of  claim 11  wherein the borehole is curved. 
     
     
         14 . The method of  claim 13  further comprising providing a plurality of substantially horizontal boreholes extending from the bottom of the curved borehole. 
     
     
         15 . The method of  claim 11  wherein the heating element is self-contained within the borehole. 
     
     
         16 . The method of  claim 11  further comprising providing a surface mounted energy source and a conduit or cable extending through the gas seal to the heating element to connect the heating element to the surface mounted energy source. 
     
     
         17 . The method of  claim 16  wherein the surface mounted energy source is solar powered. 
     
     
         18 . The method of  claim 11  further comprising providing a surface located collector and condensor connected to the borehole through the extraction tube or conduit for collecting and condensing vapor from the borehole when released by the heating element. 
     
     
         19 . The method of  claim 18  wherein the collector and condensor maintains a sufficiently low pressure in the borehole to allow vapor released by the heating element to flow to the collector and condensor. 
     
     
         20 . The method of  claim 19  wherein the collector and condensor maintains the pressure in the borehole below the boiling pressure of the volatile substance being recovered, corresponding with the temperature of the heated subsurface region of the well.