Method for heating a molten-salt battery to its operation temperature

Abstract

A method for heating a molten-salt battery to its operation temperature is disclosed. The method comprises: drilling an injection borehole and a production borehole into the ground until the temperature of a bedrock surrounding the injection borehole and the production borehole is above 280 °C, and connecting the injection borehole and production borehole by a fracture system, and adding water to the injection borehole to cause a first steam stream with a temperature above 280 °C to rise from the production borehole, and adding a second steam stream with a temperature above 100 °C at the opening of the production borehole, and mixing the first steam stream and the second steam stream to obtain a third steam stream with a temperature in the range of 250 - 280 °C, and using the third steam stream to heat a molten-salt battery to its operation temperature of 250 - 280 °C.

Description

[0001] METHOD FOR HEATING A MOLTEN-SALT BATTERY TO ITS OPERATION TEMPERATURE

[0002] FIELD

[0003] The present disclosure relates to a method for heating a molten-salt battery to its operation temperature .

[0004] BACKGROUND

[0005] Molten-salt batteries offer several advantages , including high energy density and efficiency, making them suitable for large-scale energy storage applications . However, molten-salt batteries require high operating temperatures and heating the molten-salt to its operating temperature requires a lot of energy . Therefore, the inventor has recogni zed the need to provide a method for heating a molten-salt battery to its operating temperature using geothermal energy .

[0006] SUMMARY

[0007] A method for heating a molten-salt battery to its operation temperature is disclosed . The method comprises :

[0008] - drilling an inj ection borehole and a production borehole into the ground until the temperature of a bedrock surrounding the inj ection borehole and the production borehole is above 280 ° C, and

[0009] - connecting the inj ection borehole and production borehole by a fracture system, and

[0010] - adding water to the inj ection borehole to cause a first steam stream with a temperature above 280 ° C to rise from the production borehole , and

[0011] - adding a second steam stream with a temperature above 100 ° C at the opening of the production borehole , and - mixing the first steam stream and the second steam stream to obtain a third steam stream with a temperature in the range of 250 - 280 ° C, and

[0012] - us ing the third steam stream to heat a mol ten-salt battery to its operation temperature of 250 - 280 ° C .

[0013] BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawing, which is included to provide a further understanding of the invention and constitute a part of this specification, illustrate embodiments of the invention and together with the description help to explain the principles of the invention . In the drawing :

[0015] Figure 1 is a schematic illustration of a method for heating a molten-salt battery to its operation temperature .

[0016] DETAILED DESCRIPTION

[0017] The present disclosure relates a method for heating a molten-salt battery to its operation temperature , wherein the method comprises :

[0018] - drilling an inj ection borehole and a production borehole into the ground until the temperature of a bedrock surrounding the inj ection borehole and the production borehole is above 280 ° C,

[0019] - connecting the inj ection borehole and production borehole by a fracture system, and

[0020] - adding water to the inj ection borehole to cause a first steam stream with a temperature above 280 ° C to rise from the production borehole , and

[0021] - adding a second steam stream with a temperature above 100 ° C at the opening of the production borehole , and - mixing the first steam stream and the second steam stream to obtain a third steam stream with a temperature in the range of 250 - 280 ° C, and

[0022] - using the third steam stream to heat a molten-salt battery to its operation temperature of 250 - 280 ° C .

[0023] The expression "inj ection borehole" should be understood in this specification, unless otherwise stated, as a well drilled into the ground for the purpose of inj ecting fluids ( such as water) . The expres sion "production borehole" should be understood in this specification, unless otherwise stated, as a well drilled into the ground to extract fluids ( such as gas ) . Inj ection and production boreholes can be connected through a fracture system, where the fractures act as pathways for fluid movement . In naturally or artificially fractured reservoirs , the fractures enhance the permeability of the rock, allowing the inj ected fluids to flow efficiently from the inj ection borehole to the production borehole .

[0024] A fracture system should be understood in this specification, unless otherwise stated, as a network of cracks , fissures , or fractures within a rock formation that can significantly influence the movement of fluids such as water or gas through the subsurface . These fractures may form naturally or they can be artificially created or expanded through techniques like hydraulic stimulation .

[0025] In one embodiment , the fracture system is widened by hydraulic stimulation . Hydraulic stimulation should be understood in this specification, unless otherwise stated as a technique used to enhance the permeability of a rock formation by inj ecting fluids at high pressure into the subsurface to create or expand fractures within the rock . Water may be inj ected to inj ection borehole and as the water travels through the hot rocks , it absorbs the heat and turns into steam . The steam may then be extracted through production borehole and brought to the surface , where it can be used to heat the molten-salt battery .

[0026] The second steam stream with a temperature in the range of 100 - 120 ° C is added at the opening of the production borehole . The expression "opening of the production borehole" means the opening of the borehole at the surface .

[0027] The distance between the inj ection borehole and the one or more production boreholes depends on the si ze of the naturally appearing fracture zone that opens up . Therefore , the boreholes may be located in volcanic areas , where boreholes only a few hundred meters deep are expected to produce sufficiently hot steam . In one embodiment , the ground, wherein the boreholes are drilled is a volcanic ground . Volcanic ground also known as volcanic terrain or volcanic soil , should be understood in this specification, unless otherwise stated, as an area of land that has been signi ficantly influenced by volcanic activity .

[0028] In one embodiment , the inj ection borehole and the production borehole are drilled into the ground unti l the temperature of the bedrock surrounding the inj ection borehole and the production borehole is in the range of 280 - 300 ° C, or 290 - 300 ° C, or 280 - 290 ° C . The drilled boreholes may be vertical or slightly obl ique , extending down into the Earth ' s crust until a depth is reached where the temperature of the surrounding rock is 280 ° C . Then the commonly used method of hydraulic stimulation may be appl ied to widen the naturally occurring fracture system, connecting the inj ection borehole with the production borehole .

[0029] A molten-salt battery is a type of battery that uses molten salts as the electrolyte . The molten-salt battery may function in the temperature range 250 to 280 ° C to keep the salts in a liquid state , enabling ion conduction . Molten-salt batteries offer several advantages , including high energy density and efficiency, making them suitable for large-scale energy storage applications . In one embodiment , the molten salt battery is a sodium metal chloride battery . In one embodiment , the molten salt battery is a sodium nickel chloride battery . A molten-salt battery may contain multiple cells . Each individual cell of the molten-salt battery may be penetrated by a metal tube through which a steam stream may be passed to heat the cell to keep the salts in a l iquid state , enabling ion conduction . In one embodiment , metal tubes penetrate the molten-salt battery cells . In one embodiment , the third steam stream is passed through the metal tubes inside the cells of molten-salt battery to heat the molten-salt battery to its operation temperature of 250 - 280 ° C . At normal ambient temperatures around or below 100 ° C no chemical reactions take place in the cell of molten-salt battery, which consequently retains its electric charge infinitely long unless the electricity is recovered by a user . In this state , the battery is ecofriendly and can neither burn, explode , nor cause any other harm to the environment .

[0030] In one embodiment , the second steam stream with a temperature in the range of 100 - 120 ° C or 100 - 110 ° C or around 100 ° C is added at the opening of the production borehole . The second steam stream with a temperature in the range of 100 - 120 ° C may be produced by boiling water in a cauldron placed close to the opening of the production borehole .

[0031] In one embodiment , the cells of the molten- salt battery comprises metal tubes and the third steam stream is passed through the metal tubes to heat the molten-salt battery to its operation temperature of 250

[0032] 280 ° C . In one embodiment , the second steam stream is produced by boiling water in a cauldron placed close to the opening of the production borehole . In one embodiment , the second steam stream is produced by boiling water in a cauldron placed at the opening of the production borehole . In one embodiment , the cauldron i s a pressure cauldron with a metal tube and the second steam stream is inj ected through the metal tube into the first steam stream . The metal tube may be 5 - 10 m long with a no z zle containing one or more holes to produce effi cient mixing of the steams . In one embodiment , a thermometer coupled to a device that mechanically regulates the amount of the second steam stream is used to maintain the temperature of the third steam stream within the range of 250 - 280 ° C .

[0033] When the molten-salt battery has been heated to its operation temperature , electricity generated by a steam turbine may be used to charge the empty or discharged battery before it is delivered to the end user .

[0034] EXAMPLE

[0035] Figure 1 illustrates an example of a method for heating a molten-salt battery to its operation temperature . An inj ection borehole 101a and a production borehole 102b were drilled into the ground until the temperature of a bedrock surrounding the inj ection borehole 101a and the production borehole 101b is in the range of 280 - 300 ° C . The inj ection borehole 101a and production borehole 101b were connected by a fracture system A . The fracture system A may be widened by using hydraulic stimulation to open existing fractures to enable water or steam stream to flow from one borehole to another . Water 1 was then added to the inj ection borehole 101a, where the heat of the surrounding rock caused it to turn into a first steam stream 2 with a temperature above 280 ° C . The first steam stream 2 may then be extracted through production borehole 101b and brought to the surface . Then a second steam stream 3 with a temperature in the range of 100 - 120 ° C was added at the opening of the production borehole 101b . Then the first steam stream 2 and the second steam stream 3 were mixed to obtain a third steam stream 4 with a temperature in the range of 250 - 280 ° C . Then the third steam stream 4 was used to heat a molten-salt battery 102 to its operation temperature of 250 - 280 ° C .

[0036] It is obvious to a person skil led in the art that with the advancement of technology, the basic idea may be implemented in various ways . The embodiments are thus not limited to the examples described above ; instead they may vary within the scope of the claims .

[0037] The embodiments described hereinbefore may be used in any combination with each other . Several of the embodiments may be combined together to form a further embodiment . A method as disclosed herein, may comprise at least one of the embodiments described hereinbefore . It wi ll be understood that the benef its and advantages described above may relate to one embodiment or may relate to several embodiments . The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages . It will further be understood that reference to ' an ' item refers to one or more of those items . The term "compri sing" is used in thi s specification to mean including the feature ( s ) or act ( s ) followed thereafter, without excluding the presence of one or more additional features or acts .

Claims

CLAIMS1 . A method for heating a molten-salt battery to its operation temperature , wherein the method comprises : drilling an inj ection borehole and a production borehole into the ground until the temperature of a bedrock surrounding the inj ection borehole and the production borehole is above 280 ° C, and connecting the inj ection borehole and production borehole by a fracture system, and adding water to the inj ection borehole to cause a first steam stream with a temperature above 280 ° C to ri se from the production borehole , and adding a second steam stream with a temperature above 100 ° C at the opening of the production borehole , and mixing the first steam stream and the second steam stream to obtain a third steam stream with a temperature in the range of 250 - 280 ° C, and using the third steam stream to heat a molten-salt battery to its operation temperature of 250 - 280 ° C .2 . The method of claim 1 , wherein in the temperature of first steam stream is in the range of 280 ° C - 300 ° C .3 . The method of any one of the preceding claims , wherein the second steam stream with a temperature in the range of 100 - 120 ° C is added at the opening of the production borehole4 . The method of any one of the preceding claims , wherein the inj ection borehole and the production borehole are drilled into the ground until the temperature of the bedrock surrounding the inj ectionborehole and the production borehole is in the range of 280 - 300 ° C5 . The method of any one of the preceding claims , wherein the fracture system is widened by hydraulic stimulation .6 . The method of any one of the preceding claims , wherein the cells of the molten-salt battery comprises metal tubes and the third steam stream is passed through the metal tubes to heat the molten-salt battery to its operation temperature of 250 - 280 ° C .7 . The method of any one of the preceding claims , wherein the second steam stream i s produced by boiling water in a cauldron placed close to the opening of the production borehole .8 . The method of any one of the preceding claims , wherein the cauldron is a pressure cauldron with a metal tube and the second steam stream is inj ected through the metal tube into the first steam stream .9 . The method of any one of the preceding claims , wherein the method further comprises a thermometer coupled to a device that mechanically regulates the amount of the second steam stream .

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