Geothermal plant with cascaded steam generators for industrial equipment

Abstract

This invention relates to a geothermal device with a cascaded steam generator for industrial equipment, the geothermal device comprising: (a) a geothermal source configured to provide brine at a temperature in the range of 120°C to 300°C; and (b) at least two heat exchangers (2, 3, 4) through which the brine can flow on the primary side of each of the at least two heat exchangers, and the primary side of each heat exchanger (2, 3, 4) is cascaded relative to its adjacent heat exchanger (2, 3, 4), wherein each heat exchanger (2, 3, 4) has a secondary side configured such that supply water (c1, c2, c3) evaporates due to heat transfer from the primary side to the secondary side, or circulating water is heated in the secondary loop, and thus an evaporator (15, 16, 17) arranged in the secondary loop causes the supply water (c1, c2, c3) to evaporate due to heat transfer from the primary side to the secondary side, or circulating water is heated in the secondary loop, and thus an evaporator (15, 16, 17) is arranged in the secondary loop to cause the supply water (c1, c2, c3) to evaporate due to heat transfer from the primary side to the secondary side. (a) Evaporation; (b) A first pipeline fluidly connecting the removal site (a) of the geothermal source to the cascaded primary side of these heat exchangers (2, 3, 4); (c) Each of these heat exchangers (2, 3, 4) having a corresponding downstream mineral removal unit (12, 13, 14); (d) A first brine pump (1) arranged along the main flow direction between the removal site (a) and the primary side of the first heat exchanger (2), thus delivering brine from the source to the corresponding cascaded primary side of these heat exchangers (2, 3, 4) and their corresponding downstream mineral removal units (12, 13, 14); and (e) An outlet pipeline fluidly connected to the last mineral removal unit (14) arranged along the main flow direction, wherein the outlet pipeline extends into the geothermal source such that the outlet of the outlet pipeline (b) is at least 100 mm away from the removal site (a). The distance is m, preferably at least 1500 m, and particularly preferably at least 2500 m. The invention further relates to a method of operating a geothermal device according to the invention.

Description

[0001] The present invention relates to a geothermal device with a cascaded steam generator for industrial equipment, the geothermal device comprising: a geothermal source configured to provide brine at a temperature in the range of 120°C to 300°C; at least two heat exchangers through which the brine can flow on the primary side of each of the at least two heat exchangers, and the primary sides of respective heat exchangers are cascaded relative to their adjacent heat exchangers, wherein each respective heat exchanger has a secondary side configured such that supply water evaporates due to heat transfer from the primary side to the secondary side, or circulating water is heated in the secondary loop, and thus an evaporator arranged in the secondary loop causes the supply water to evaporate.

[0002] Typically, heat pumps for generating heat, particularly for generating steam, are known. In this context, a specific embodiment of a heat pump is a geothermal device. This geothermal device uses hot brine from a geothermal source as a heat source to generate steam or useful heat.

[0003] Geothermal equipment is introduced in the Springer textbook "Geothermie" (Geothermal Energy), 3rd edition, 2020, authored by Ingrid Stober and Kurt Bucher. Page 179 describes a geothermal system that uses brine from a geothermal source to power plants or buildings. It illustrates the cascading use of heat from the brine at various temperature levels, with the heat at the highest temperature level used for power generation in a power plant. As heat is extracted for power generation, the brine is correspondingly placed at a lower temperature level, where it is used for food processing or cooling equipment. Due to the heat extraction, the brine is then placed at an even lower temperature level, where it is used to heat buildings or greenhouses. Finally, due to the heat extraction, the brine is placed at the lowest temperature level still usable for equipment, where it is used for fish farming, before being returned to the geothermal source.

[0004] A drawback of this type of geothermal equipment is that it cannot generate steam for industrial applications. This is because these geothermal devices only provide electricity and useful heat for various applications, such as heating buildings. No industrial steam is generated. Another disadvantage is that mineral deposits can clog the geothermal equipment.

[0005] CN 114321858 A discloses a geothermal device for generating steam, which includes a heat pump and a waste heat system with multi-stage steam generators. In this geothermal device, the temperature level of the steam generated by the heat pump is higher than the temperature level of the steam generated by the multi-stage cascaded steam generators present in the device. The multi-stage steam generators represent corresponding flash tanks.

[0006] A drawback of this type of geothermal equipment is that generating steam requires a complex and expensive heat pump with a separate working medium. Furthermore, the brine flowing through the first heat exchanger, the heat pump's evaporator, and the second heat exchanger for waste heat recovery lacks both chemical treatment of the brine and consideration for potential mineral precipitation. This leads to a risk of problems, for example, if mineral precipitation occurs in the heat exchangers. Excessive precipitation can cause the heat exchangers to become clogged due to the formation of deposits, necessitating a shutdown of the equipment.

[0007] Therefore, the present invention addresses the problem of providing a geothermal device that efficiently and reliably generates steam for industrial equipment. Another problem addressed by the present invention is to provide a geothermal device that can operate stably throughout the entire operating duration without forming deposits that would significantly increase the pressure loss associated with transporting brine through the geothermal device. A further problem addressed by the present invention is to provide a geothermal device that can remove minerals from brine.

[0008] According to the invention, these problems are solved by the geothermal device according to claim 1 and the method of operating the geothermal device according to claim 6. Advantageous embodiments of the geothermal device are given in claims 2 to 5, while advantageous embodiments of the method of operating the geothermal device are given in claims 7 to 15.

[0009] The geothermal equipment with cascaded steam generators for industrial use according to the present invention includes:

[0010] (a) A geothermal source configured to provide brine at a temperature ranging from 120°C to 300°C.

[0011] (b) At least two heat exchangers, wherein the brine is capable of flowing through the primary side of each of the at least two heat exchangers, and the primary side of each heat exchanger is cascaded relative to its adjacent heat exchanger, wherein each heat exchanger has a secondary side configured such that...

[0012] The supplied water evaporates due to heat transfer from the primary side to the secondary side.

[0013] Alternatively, the circulating water is heated in the secondary loop, and an evaporator, thus arranged in the secondary loop, causes the supply water to evaporate.

[0014] (c) A first pipeline that fluidly connects the geothermal source removal site (a) to the cascaded primary side of these heat exchangers.

[0015] (d) Each of these heat exchangers has a corresponding downstream mineral removal unit.

[0016] (e) A first brine pump, arranged along the main flow direction between the removal site (a) and the primary side of the first heat exchanger, thus delivering the brine from the source to the corresponding cascaded primary sides of these heat exchangers and their respective downstream mineral removal units, and

[0017] (f) An outflow line fluidly connected to the final mineral removal unit arranged along the main flow direction, wherein the outflow line extends into the geothermal source such that the outlet of the outflow line is at least 100 m, preferably at least 1500 m, and particularly preferably at least 2500 m away from the removal site (a).

[0018] The advantages of the geothermal equipment according to the present invention are that, during operation, it efficiently processes brine, preventing the flow channel walls of the cascaded heat exchangers from becoming clogged due to deposit formation, which would significantly increase pressure losses across the corresponding heat exchangers or even cause blockage of the corresponding heat exchangers. Simultaneously, due to the different temperature levels of the heat exchangers, different minerals are extracted in the mineral removal unit connected downstream of the respective heat exchangers. Furthermore, it ensures efficient, reliable, and robust steam generation for use as industrial steam in industrial applications.

[0019] In this document, "geothermal source" includes production wells for transporting brine and injection wells for returning treated brine.

[0020] In this case, the removal site corresponds to the bottom of the production well, while the return site corresponds to the bottom of the injection well.

[0021] If the geothermal source is located at a depth of 3000 m to 4000 m, the distance between the removal site and the return site should preferably be in the range of 1.0 km to 2.5 km.

[0022] In this document, "pipeline" includes one or more pipes that can be joined together by pipe fittings to form a pipeline. Additionally, a pipeline may include, for example, pipe installation systems, fittings, and thermal and mechanical insulation components. Pipelines are used to transport fluids and transfer mechanical and / or thermal energy. For example, a pipeline may be located in a production well or injection well to fluidly connect the corresponding removal or return point to the brine pump and / or additional pipes or pipelines of a geothermal facility.

[0023] In this document, a "heat exchanger" is a device capable of transferring heat from one fluid to another. For example, a plate heat exchanger or a shell-and-tube heat exchanger can be used.

[0024] In this document, a "mineral removal unit" is a device for removing minerals or other substances from brine. In principle, all suitable separation processes can be used to remove minerals or other substances from brine, such as filtration, phase separation, extraction, adsorption, or precipitation. The minerals or other substances can be reused. For example, lithium can be used in the production of batteries.

[0025] The detailed configuration of the mineral removal unit also depends on the type of minerals to be separated. On one hand, the mineral removal unit is used to separate solids that precipitate from the brine due to cooling or the addition of a precipitating agent (e.g., sulfuric acid used to precipitate barium sulfate). The separation of finely precipitated minerals follows known solid process engineering principles. Here, batch or continuous operating devices and machines are used. These devices and machines can be batch-operated filter presses, suction filters, sedimentation tanks, etc., or continuous-operated centrifuges, decanters, belt filters, etc.

[0026] On the other hand, mineral removal units can also serve the purpose of separating substances present in solution. In this case, ion exchangers or adsorption instruments can be used, which must then be regenerated under their respective conditions.

[0027] In both cases, in addition to the aforementioned core devices or machines, the mineral removal unit also includes necessary peripheral equipment, such as solvent reservoirs, rinse water containers, pumps, and corresponding piping systems and fittings.

[0028] In this document, “purification of brine” is the process of removing minerals or other substances from brine in order to reduce the formation of deposits in geothermal equipment (such as in cascaded heat exchangers), so that the geothermal equipment is not clogged, or the pressure loss of brine between the production well and the injection well during operation does not become too large.

[0029] In this document, "extraction from brine" refers to the process of removing minerals or other substances from brine, which are then reused. In this context, sediment formation can also occur in geothermal equipment, such as in cascaded heat exchangers. It is also essential to minimize potential sediment formation to prevent clogging of the geothermal equipment or excessive pressure loss of the brine between the production and injection wells during operation.

[0030] In this document, "secondary loop" refers to the loop mass flow that receives heat flow from the primary side of the heat exchanger.

[0031] The secondary loop may also include branches, such as bypasses parallel to the evaporators. Multiple evaporators may also exist in the secondary loop, fluidly connected to each other, for example, in parallel interconnection, series interconnection, or a combination of parallel and series interconnection.

[0032] In this document, "evaporator" refers to a heat exchanger or flash tank.

[0033] If the evaporator is a heat exchanger, the heat exchanger transfers heat from its primary side to its secondary side, so that the liquid supplied to the secondary side, preferably water, and particularly preferably demineralized water, evaporates at least partially.

[0034] Evaporators may also include additional standard components such as control valves, pressure regulators, flow controllers, or sensors. Therefore, evaporators may also include closed-loop control systems. The term "evaporator" can also generally be understood to refer to two or more evaporators fluidly connected to each other in series or parallel.

[0035] Examples of suitable heat exchangers for evaporators are thin-film evaporators, Robert evaporators, falling-film evaporators, natural circulation evaporators, and forced circulation evaporators. These evaporators can be designed as shell-and-tube heat exchangers or plate heat exchangers. Suitable evaporators are known to those skilled in the art and are described in particular in the following: SPX, Evaporator Handbook, APV Americas, Engineering Systems, Separation Technology, 4th Edition, available in […]. https: / / userpages.umbc.edu / ~dfrey1 / ench445 / apv_evap.pdf Accessed on November 20, 2023.

[0036] In this document, "flash tank" is one possible form of evaporator. The flash tank has a tank, which preferably includes expansion nozzles in its upper region. Fluid, preferably water, and particularly preferably demineralized water, is supplied to the flash tank. The fluid upstream of the expansion nozzles is superheated relative to the pressure within the flash tank. If expansion nozzles are present, fluid is supplied to the flash tank through the inlet of the expansion nozzles. Unevaporated fluid accumulates in the lower region of the flash tank and is discharged through the flash tank outlet. Evaporated fluid in the flash tank is discharged through a steam outlet in the upper region of the flash tank. Separate fluid, preferably water, and particularly preferably demineralized water, can also be supplied to the flash tank via a supply line.

[0037] In this document, "compressor" refers to a machine that compresses gases. A suitable example of a compressor is a geared turbo compressor. Compressors are typically designed to have multiple compression stages and intermediate stages, with each intermediate stage equipped with a device for intercooling.

[0038] The term "fluidly connected" in this document means that typically two or more permeable components (e.g., multiple flow tubes) are connected to each other so that fluid can flow through these connected components. Generally, there should be a sufficient degree of technical impermeability as the fluid flows through.

[0039] In this document, "liquid" means a single-phase or multiphase fluid. Therefore, a liquid is free-flowing and transportable through the primary loop. A liquid may also include gaseous and / or solid components, provided that the liquid remains transportable.

[0040] In this document, "heat transfer fluid" means a single-phase or multiphase fluid, such as a liquid, gas, steam, or a mixture thereof. Therefore, heat transfer fluids are free-flowing. Heat transfer fluids may also include solid components, provided that the heat transfer fluid remains transportable. For example, heat transfer fluids may be heating steam, air, demineralized water, filtered river water, or a reaction mixture from a reactor.

[0041] The heat transfer fluid used is preferably one of the following:

[0042] Water, demineralized water, heat transfer oils (e.g., Therminol VP1, Xceltherm 600, Syltherm XLT, Dowtherm A, Calorie HAT 43, or Marlotherm SH), sunflower oil, organic liquids (e.g., ethanol, propane, butane, isobutanol, isoamyl alcohol, or octane), ammonia, mineral oils (e.g., engine oil or Mobiltherm 605), inorganic molten salts, and liquid metals (e.g., sodium, lead, bismuth, potassium, and their alloys).

[0043] In a preferred embodiment of the geothermal equipment according to the invention, a second brine pump is arranged along the main flow direction between the final mineral removal unit and the outlet of the outflow pipeline, so that the treated brine is transported to the outlet of the outflow pipeline.

[0044] The advantage of this is that the treated brine is delivered directly and reliably to the return site.

[0045] In a preferred embodiment of the geothermal device according to the invention, if a secondary loop exists, the corresponding heat exchanger includes a pump for circulating water in the secondary loop, thus ensuring water circulation. Furthermore, the water mass flow rate can be set by means of, for example, a variable speed pump.

[0046] In a preferred embodiment of the geothermal device according to the invention, the heat exchanger has a corresponding downstream compressor on its secondary side or in the secondary circuit, which is configured in each case to compress the generated steam. Thus, the steam is compressed, making it usable in many industrial processes. By interconnecting two or more compressors or by the number of compressor stages, the steam can be compressed accordingly to meet the needs of the intended application.

[0047] In a preferred embodiment of the geothermal device according to the invention, there are exactly three cascaded heat exchangers for generating steam, and each of these three heat exchangers has a corresponding downstream mineral removal unit. By means of the exactly three cascaded heat exchangers, the corresponding downstream mineral removal units set exactly three temperature levels for separating the minerals. Therefore, minerals can be separated from the brine at three different temperature levels, which automatically leads to the concentration of the separated minerals based on these three temperature levels, since the corresponding solubility of various minerals in the brine depends largely on temperature. To obtain minerals from the brine, minerals have been pre-selected accordingly due to the three different temperature levels. Especially in the case of three cascaded heat exchangers, the economic cost remains related to the acquisition of minerals and the generation of steam.

[0048] Another subject of the invention relates to a method of operating a geothermal device according to the invention.

[0049] In a preferred embodiment of the method for operating a geothermal device according to the present invention, the method includes the following steps:

[0050] a) Brine is pumped from the geothermal source to the primary side of a series of cascaded heat exchangers via a first brine pump, wherein the temperature of the brine at the inlet of the primary side of the first heat exchanger arranged along the main flow direction is in the range of 120°C to 300°C.

[0051] b) Transfer at least some of the heat from the brine from the primary side of the respective heat exchanger.

[0052] I. Water supplied to the secondary side, therefore the supply water is evaporated, or

[0053] II. If a secondary loop exists:

[0054] Water circulates in the secondary loop of the corresponding heat exchanger, wherein the temperature of the water in the corresponding secondary loop connected upstream of the evaporator is in the range of 40°C to 195°C, and thus the water supplied to the evaporator is evaporated.

[0055] c) Minerals are removed by means of a mineral removal unit connected downstream of the corresponding heat exchanger, and

[0056] d) The treated brine is conveyed from the outlet of the final mineral removal unit, which is arranged along the main flow direction, to the outlet of the outflow line, wherein the temperature at the outlet of the outflow line is in the range of 35°C to 115°C.

[0057] The advantage of the method for operating geothermal equipment according to the present invention is that it efficiently treats brine, preventing the flow channel walls of the cascaded heat exchangers from becoming clogged due to sediment formation, which would significantly increase pressure losses across the corresponding heat exchangers, or even cause blockage of the corresponding heat exchangers. Simultaneously, due to the different solubilities of minerals at different temperature levels within the heat exchangers, different minerals are extracted in a mineral removal unit connected downstream of the heat exchangers.

[0058] In a preferred embodiment of the method for operating a geothermal device according to the invention, the temperature of the brine at the inlet on the primary side of the first heat exchanger arranged along the main flow direction is in the range of 120°C to 200°C, preferably in the range of 140°C to 180°C. The temperature of the brine at the outlet on the primary side of the first heat exchanger is in the range of 105°C to 155°C.

[0059] Therefore, the first mineral is separated from the brine by the downstream mineral removal unit, and the pressure loss across the first heat exchanger does not increase significantly due to the possible formation of deposits on the flow channel walls of the first heat exchanger.

[0060] In a preferred embodiment of the method for operating a geothermal device according to the present invention, the temperature of the brine at the inlet of the primary side of the second heat exchanger arranged along the main flow direction is in the range of 105°C to 155°C, and the temperature of the brine at the outlet of the primary side of the second heat exchanger is in the range of 75°C to 120°C.

[0061] Therefore, additional minerals are separated from the brine through the downstream mineral removal unit, and the pressure loss across the second heat exchanger is not significantly increased due to the possible formation of deposits on the flow channel walls of the second heat exchanger.

[0062] In a preferred embodiment of the method of operating a geothermal device according to the invention, the temperature of the brine at the inlet of the primary side of the third heat exchanger arranged along the main flow direction is in the range of 75°C to 120°C, and the temperature of the brine at the outlet of the primary side of the third heat exchanger is in the range of 35°C to 115°C, preferably in the range of 40°C to 85°C, and particularly preferably in the range of 45°C to 55°C.

[0063] Therefore, additional minerals are separated from the brine through the downstream mineral removal unit, and the pressure loss across the third heat exchanger is not significantly increased due to the potential formation of deposits on the flow channel walls of the third heat exchanger.

[0064] In a preferred embodiment of the method for operating a geothermal device according to the invention, there are exactly three heat exchangers for generating steam, each of which has a corresponding downstream mineral removal unit. By means of exactly three cascaded heat exchangers, exactly three temperature levels are set by the corresponding downstream mineral removal units for mineral separation. Therefore, minerals can be separated from the brine at three different temperature levels, which automatically leads to the concentration of the separated minerals based on these three temperature levels. To obtain minerals from the brine, minerals have been pre-selected correspondingly due to the three different temperature levels. Especially in the case of three cascaded heat exchangers, the economic cost remains related to the acquisition of minerals and the generation of steam.

[0065] In a preferred embodiment of the method for operating a geothermal device according to the invention, the first mineral removal unit along the main flow direction separates at least partially, preferably in a major proportion, one of the following substances from the brine for brine purification purposes: Fe, Pb, and Al silicates. For extraction purposes, the first mineral removal unit along the main flow direction separates at least partially, preferably in a major proportion, one of the following substances from the brine for brine purification purposes: Zn, Sr, CaF, and Mn.

[0066] Therefore, the downstream heat exchanger does not experience a significant increase in pressure loss across the downstream heat exchanger due to the formation of deposits that occur during the operation of the geothermal equipment. Furthermore, one or more substances selected from the group consisting of Zn, Sr, CaF, and Mn can be extracted at least partially from the brine. Additionally, the heat flow extracted by the first heat exchanger is also used to generate steam.

[0067] In a preferred embodiment of the method for operating a geothermal device according to the invention, a second mineral removal unit along the main flow direction separates at least partially, and preferably in a major proportion, one of the following substances from the brine for brine purification purposes: Mg, P, and Zn. For extraction purposes, a first mineral removal unit along the main flow direction separates at least partially, and preferably in a major proportion, one of the following substances from the brine: Mg, Mn, F, P, Sr, and Zn.

[0068] Therefore, the downstream heat exchanger does not experience a significant increase in pressure loss across the downstream heat exchanger due to the formation of deposits that occur during the operation of the geothermal equipment. Furthermore, one or more substances selected from the group consisting of Mg, Mn, F, P, Sr, and Zn can be extracted at least partially from the brine. Additionally, the heat flow extracted by the second heat exchanger is also used to generate steam.

[0069] In a preferred embodiment of the method of operating a geothermal device according to the invention, a third mineral removal unit along the main flow direction separates, for extraction purposes, at least partially and preferably in a major proportion, one of the following substances from the brine: Mn, Sr, F and Ba2+.

[0070] Therefore, one or more substances selected from the group consisting of Mn, Sr, F, and Ba2+ are extracted at least partially from the brine. Furthermore, the heat flow drawn from the third heat exchanger is also used to generate steam.

[0071] In a preferred embodiment of the method for operating a geothermal device according to the invention, due to the addition of H2SO4, Ba2+ precipitates out of the brine at least partially, and preferably in a major proportion, in the form of barium sulfate. Therefore, the barium sulfate is effectively extracted.

[0072] In a preferred embodiment of the method for operating a geothermal device according to the invention, the precipitated barium sulfate is used as a filler in plastics, as a filler in colloidal substances, as a white pigment for example in coatings, or as a whitening agent.

[0073] In a preferred embodiment of the method for operating a geothermal device according to the invention, the brine is maintained at a pressure such that neither evaporation nor degassing of the brine occurs. This provides the advantage that no precipitation occurs from the brine and no liquid / gas mixture with lower energy density due to its lower density is produced.

[0074] The invention is illustrated in detail below with reference to the accompanying drawings. The drawings should be considered schematic diagrams. The drawings do not limit the invention, for example, regarding specific dimensions or design variations. The drawings show:

[0075] Figure 1Geothermal equipment used to generate steam for industrial equipment, wherein the supply water evaporates on the secondary side of the corresponding heat exchanger due to heat transfer from the primary side to the secondary side.

[0076] Figure 2 Geothermal equipment for generating steam for industrial equipment, wherein the secondary side of the corresponding heat exchanger is configured such that circulating water is heated in the secondary loop, and thus an evaporator arranged in the secondary loop evaporates the supply water.

[0077] List of reference numerals used in the figures:

[0078]

[0079]

[0080] Figure 1 A first embodiment of a geothermal device for generating steam for industrial equipment according to the present invention is shown, wherein the respective secondary sides of three cascaded heat exchangers 2, 3 and 4 are configured such that supply water c1, c2, c3 can evaporate due to heat transfer from the primary side to the secondary side.

[0081] In detail, the geothermal equipment is connected to the brine of the geothermal source via a removal point a. A first pipeline is fluidly connected to a first brine pump 1, and the first pipeline fluidly connects the removal point a to the respective primary sides of three cascaded heat exchangers 2, 3 and 4 and their respective downstream mineral removal units 12, 13 and 14.

[0082] The secondary side of the first heat exchanger 2 is configured to supply first water c1, which can then evaporate. Downstream, the first compressor 9 is configured to compress the generated steam to form higher-energy steam e1.

[0083] The secondary side of the second heat exchanger 3 is configured to supply second water c2, which can then evaporate. The downstream second compressor 10 is configured to compress the generated steam to form higher-energy steam e2.

[0084] The secondary side of the third heat exchanger 4 is configured to supply third water c3, which can then evaporate. The downstream first compressor 11 is configured to compress the generated steam to form higher-energy steam e3.

[0085] The outflow pipeline fluidly connects the third mineral removal unit 14 to the return site b, wherein the second brine pump 8 is fluidly connected to the outflow pipeline to deliver brine to the return site b. In this case, the distance between the removal site a and the return site b is 1500 m.

[0086] Figure 1 A first embodiment of a method for operating a geothermal device for generating steam for industrial equipment according to the invention is also shown, wherein the respective secondary sides of the three cascaded heat exchangers 2, 3 and 4 cause the supply water c1, c2 and c3 to evaporate due to heat transfer from the primary side to the secondary side.

[0087] In detail, the brine at the removal site a is transported by means of a first brine pump 1 through a first pipeline to the primary side of three cascaded heat exchangers 2, 3 and 4 and their corresponding downstream mineral removal units 12, 13 and 14.

[0088] The first water c1 is supplied to the secondary side of the first heat exchanger 2, and thus the supplied first water c1 evaporates. The downstream first compressor 9 compresses the generated steam to form higher energy steam e1.

[0089] The second water c2 is supplied to the secondary side of the second heat exchanger 3, and thus the supplied second water c2 evaporates. The downstream second compressor 10 compresses the generated steam to form higher-energy steam e2.

[0090] The third water c3 is supplied to the secondary side of the third heat exchanger 4, and thus the supplied third water c3 evaporates. The downstream third compressor 11 compresses the generated steam to form higher-energy steam e3.

[0091] Brine is transported from the third mineral removal unit 14 to the return site b via an outflow line, wherein a second brine pump 8 is fluidly connected to the outflow line so that it can transport the brine to the return site b. In this case, the distance between the removal site a and the return site b is 1500 m.

[0092] Figure 2 A second embodiment of a geothermal device for generating steam for industrial equipment according to the invention is shown, wherein the respective secondary sides of three cascaded heat exchangers 2, 3 and 4 are configured such that circulating water is heated in the secondary loop, and thus evaporators 15, 16 and 17 arranged in the secondary loop can evaporate supply water c1, c2 and c3.

[0093] In detail, the geothermal equipment is connected to the brine of the geothermal source via a removal point a. A first pipeline is fluidly connected to a first brine pump 1, and the first pipeline fluidly connects the removal point a to the respective primary sides of three cascaded heat exchangers 2, 3 and 4 and their respective downstream mineral removal units 12, 13 and 14.

[0094] The secondary loop of the first heat exchanger 2 is fluidly connected to the pump 5 and the first evaporator 15. The heat transfer fluid in the secondary loop is demineralized water, which is circulated in the secondary loop by the pump 5. The secondary side of the first heat exchanger 2 is also configured such that a first water c1 can be supplied to the first evaporator 15, and thus the supplied first water c1 can evaporate to form steam d1.

[0095] The secondary loop of the second heat exchanger 3 is fluidly connected to the pump 6 and the second evaporator 16. The heat transfer fluid in the secondary loop is demineralized water, which circulates in the secondary loop via the pump 6. The secondary side of the second heat exchanger 3 is also configured such that a second water c2 can be supplied to the second evaporator 16, and thus the supplied second water c2 can evaporate to form steam d2.

[0096] The secondary loop of the third heat exchanger 4 is fluidly connected to the pump 7 and the third evaporator 17. The heat transfer fluid in the secondary loop is demineralized water, which circulates in the secondary loop via the pump 7. The secondary side of the third heat exchanger 4 is also configured such that third water c3 can be supplied to the third evaporator 17, and thus the supplied third water c3 can evaporate to form steam d3.

[0097] The outflow pipeline fluidly connects the third mineral removal unit 14 to the return point b in the geothermal source, wherein the second brine pump 8 is fluidly connected to the outflow pipeline to deliver brine to the return point b. In this case, the distance between the removal point a and the return point b is 1500 m.

[0098] In principle, in this second exemplary embodiment, evaporators 15, 16 and 17 may also have corresponding downstream compressors configured to compress the corresponding generated steam d1, d2 or d3 to form steam with higher energy.

[0099] Figure 2 A second embodiment of the method of operating a geothermal device for generating steam for industrial equipment according to the invention is also shown, wherein the respective secondary sides of three cascaded heat exchangers 2, 3 and 4 are configured such that circulating water is heated in the secondary loop, and thus evaporators 15, 16 and 17 arranged in the secondary loop evaporate the supply water c1, c2 and c3.

[0100] In detail, the brine at the removal site a is transported by means of a first brine pump 1 through a first pipeline to the primary side of three cascaded heat exchangers 2, 3 and 4 and their corresponding downstream mineral removal units 12, 13 and 14.

[0101] The secondary loop of the first heat exchanger 2 is fluidly connected to the pump 5 and the first evaporator 15. The heat transfer fluid in the secondary loop is demineralized water, which is circulated in the secondary loop by the pump 5. In addition, first water c1 is supplied to the first evaporator 15, and thus the supplied first water c1 evaporates to form steam d1.

[0102] The secondary loop of the second heat exchanger 3 is fluidly connected to the pump 6 and the second evaporator 16. The heat transfer fluid in the secondary loop is demineralized water, which circulates in the secondary loop via the pump 6. In addition, a second water c2 is supplied to the second evaporator 16, and thus the supplied second water c2 evaporates to form steam d2.

[0103] The secondary loop of the third heat exchanger 4 is fluidly connected to the pump 7 and the third evaporator 17. The heat transfer fluid in the secondary loop is demineralized water, which circulates in the secondary loop via the pump 7. In addition, third water c3 is supplied to the third evaporator 17, and thus the supplied third water c3 evaporates to form steam d3.

[0104] Brine is transported from the third mineral removal unit 14 to the return site b via an outflow pipeline, wherein a second brine pump 8 is fluidly connected to the outflow pipeline to transport the brine to the return site b. In this case, the distance between the removal site a and the return site b is 1500 m.

[0105] In principle, in this second exemplary embodiment, evaporators 15, 16 and 17 may also have at least one corresponding downstream compressor that compresses the corresponding generated steam d1, d2 or d3 to form steam with higher energy. Example

[0106] For the following example, PhreeQC software is used, which performs geochemical modeling and calculations related to the chemical interaction of aqueous solutions and rocks. PhreeQC also allows for the calculation of possible precipitation types after cooling of aqueous solutions (e.g., brine). In this case, the composition of the brine is calculated as a molar concentration (in mol / L). The amount of ions present is determined by the molar concentration n, molar mass M, and correction factor k according to the formula β = M. n k is calculated. The mass concentration of the ions precipitated at the corresponding temperature level is obtained by subtracting the corresponding existing mass concentration from the current β value. Documentation for the PhreeQC software is available at the following link: https: / / pubs.usgs.gov / publication / tm6A43 (retrieved November 10, 2023).

[0107] Example 1

[0108] In Example 1, the operation according to the present invention is described. Figure 1 A method for using geothermal equipment to generate steam for industrial equipment.

[0109] In this respect, the water c1, c2, c3 supplied to the corresponding secondary sides of the three cascaded heat exchangers 2, 3 and 4 evaporates due to heat transfer from the primary side to the secondary side.

[0110] In detail, the brine at the removal site a is transported by means of a first brine pump 1 through a first pipeline to the primary side of three cascaded heat exchangers 2, 3 and 4 and their corresponding downstream mineral removal units 12, 13 and 14.

[0111] The brine was removed at its removal site a at an absolute pressure of 10 bar and a temperature of 160°C, with a mass flow rate of 360 t / h.

[0112] In this case, the saline solution contains the following substances, expressed in mg / L:

[0113]

[0114] The temperature of the brine at the inlet of the first heat exchanger 2 is 155°C, and it is cooled to 120°C by the first heat exchanger 2.

[0115] For purification purposes, the first mineral removal unit 12 removes the following substances from the brine in mg / L, the corresponding substances from the brine being related to the separated elements specified in the third column of the table:

[0116]

[0117] For extraction purposes, the first mineral removal unit 12 removes the following substances from the brine at a concentration of mg / L, the corresponding substances from the brine being associated with the elements to be extracted specified in the third column of the table:

[0118]

[0119] First water c1 is supplied to the secondary side of the first heat exchanger 2 at a temperature of 96.6°C and a mass flow rate of 24 t / h. The supplied first water c1 evaporates, producing steam with an absolute pressure of 1 bar and a temperature of 100°C. Downstream, the first compressor 9 compresses the generated steam to form higher-energy steam e1, which has an absolute pressure of 2 bar and a temperature of 181°C.

[0120] The brine at the inlet of the second heat exchanger 3 is at a temperature of 119°C, and is cooled to 85°C by the second heat exchanger 3.

[0121] For purification purposes, the second mineral removal unit 13 removes the following substances from the brine in mg / L:

[0122]

[0123] For extraction purposes, the second mineral removal unit 13 removes the following substances from the brine in mg / L, the corresponding substances from the brine being related to the separated elements specified in the third column of the table:

[0124]

[0125] The second water, c2, is supplied to the secondary side of the second heat exchanger 3 at a temperature of 79.5°C and a mass flow rate of 22 t / h. The supplied second water, c2, evaporates, producing steam with an absolute pressure of 0.525 bar and a temperature of 82.5°C. Downstream, the second compressor 10 compresses the generated steam to form higher-energy steam, e2, with an absolute pressure of 1.1 bar and a temperature of 167°C.

[0126] At the inlet of the third heat exchanger 4, the temperature of the brine is 84°C and is cooled to 50°C by the third heat exchanger 4.

[0127] For purification purposes, the third mineral removal unit 14 removes the following substances from the brine in mg / L, the corresponding substances from the brine being related to the separated elements specified in the third column of the table:

[0128]

[0129] For extraction purposes, the third mineral removal unit 14 removes the following substances from the brine in mg / L, the corresponding substances from the brine being related to the extracted elements specified in the third column of the table:

[0130]

[0131] Furthermore, any remaining barium ions can be precipitated with sulfuric acid to form slightly soluble barium sulfate. Barium sulfate can then be extracted as a valuable material.

[0132] The third water, c3, is supplied to the secondary side of the third heat exchanger 4 at a temperature of 45.7°C and a mass flow rate of 21 t / h. The supplied third water, c3, evaporates, producing steam with an absolute pressure of 0.11 bar and a temperature of 47.7°C. Downstream, the third compressor 11 compresses the generated steam to form higher-energy steam, e3, with an absolute pressure of 0.22 bar and a temperature of 120.2°C.

[0133] Brine is transported from the third mineral removal unit 14 to the return site b via an outflow pipeline, wherein a second brine pump 8 is fluidly connected to the outflow pipeline to transport the brine to the return site b. In this case, the distance between the removal site a and the return site b is 1500 m.

[0134] Example 2

[0135] In this Example 2, the operation according to the present invention is described. Figure 2 The method for generating steam for industrial equipment using geothermal equipment. The three evaporators 15, 16 and 17 also each represent flash tanks.

[0136] The respective secondary sides of the three cascaded heat exchangers 2, 3 and 4 are configured such that the circulating water is heated in the secondary loop, and thus the evaporators 15, 16 and 17 arranged accordingly in the secondary loop evaporate the supply water c1, c2 and c3.

[0137] In detail, the brine at the removal site a is transported by means of a first brine pump 1 through a first pipeline to the primary side of three cascaded heat exchangers 2, 3 and 4 and their corresponding downstream mineral removal units 12, 13 and 14.

[0138] The brine was removed at its removal site a at an absolute pressure of 10 bar and a temperature of 160°C, with a mass flow rate of 360 t / h.

[0139] In this case, the saline solution contains the following substances, expressed in mg / L:

[0140]

[0141] The temperature of the brine at the inlet of the first heat exchanger 2 is 155°C, and it is cooled to 120°C by the first heat exchanger 2.

[0142] For purification purposes, the first mineral removal unit 12 removes the following substances from the brine in mg / L, the corresponding substances from the brine being related to the separated elements specified in the third column of the table:

[0143]

[0144] For extraction purposes, the first mineral removal unit 12 removes the following substances from the brine at a concentration of mg / L, the corresponding substances from the brine being associated with the elements to be extracted specified in the third column of the table:

[0145]

[0146] The secondary loop of the first heat exchanger 2 is fluidly connected to the pump 5 and the first evaporator 15. The heat transfer fluid in the secondary loop is demineralized water, which is circulated in the secondary loop by the pump 5 at a mass flow rate of 267 t / h. First water c1 is also supplied to the first evaporator 15 at a temperature of 97.6°C and a mass flow rate of 24 t / h, so that the supplied first water c1 evaporates to form steam d1 with an absolute pressure of 1 bar and a temperature of 100°C.

[0147] The brine at the inlet of the second heat exchanger 3 is at a temperature of 119°C, and is cooled to 85°C by the second heat exchanger 3.

[0148] For purification purposes, the second mineral removal unit 13 removes the following substances from the brine in mg / L, the corresponding substances from the brine being related to the separated elements specified in the third column of the table:

[0149]

[0150] For extraction purposes, the second mineral removal unit 13 removes the following substances from the brine at a concentration of mg / L, the corresponding substances from the brine being associated with the elements to be extracted specified in the third column of the table:

[0151]

[0152] The secondary loop of the second heat exchanger 3 is fluidly connected to the pump 6 and the second evaporator 16. The heat transfer fluid in the secondary loop is demineralized water, which is circulated in the secondary loop by the pump 6 at a mass flow rate of 412 t / h. Second water c2 is also supplied to the evaporator 16 at a temperature of 78°C and a mass flow rate of 22 t / h, so that the supplied second water c2 evaporates to form steam d2 with an absolute pressure of 0.5 bar and a temperature of 81.3°C.

[0153] The temperature of the brine at the inlet of the third heat exchanger 4 is 84°C, and it is cooled to 50°C by the third heat exchanger 4.

[0154] For purification purposes, the third mineral removal unit 14 removes the following substances from the brine in mg / L, the corresponding substances from the brine being related to the separated elements specified in the third column of the table:

[0155]

[0156] For extraction purposes, the third mineral removal unit 14 removes the following substances from the brine in mg / L, the corresponding substances from the brine being related to the extracted elements specified in the third column of the table:

[0157]

[0158] Furthermore, any remaining barium ions can be precipitated with sulfuric acid to form slightly soluble barium sulfate. Barium sulfate can then be extracted as a valuable material.

[0159] The secondary loop of the third heat exchanger 4 is fluidly connected to the pump 7 and the third evaporator 17. The heat transfer fluid in the secondary loop is demineralized water, which is circulated in the secondary loop by the pump 7 at a mass flow rate of 405 t / h. Third water c3 is also supplied to the third evaporator 17 at a temperature of 43.8°C and a mass flow rate of 21 t / h, so that the supplied third water c3 evaporates to form steam d3 with an absolute pressure of 0.1 bar and a temperature of 45.8°C.

[0160] Brine is transported from the third mineral removal unit 14 to the return site b via an outflow pipeline, wherein a second brine pump 8 is fluidly connected to the outflow pipeline to transport the brine to the return site b. In this case, the distance between the removal site a and the return site b is 1500 m.

Claims

1. A geothermal device with a cascaded steam generator for use in industrial equipment, the geothermal device comprising: (a) A geothermal source configured to provide brine at a temperature ranging from 120°C to 300°C. (b) At least two heat exchangers (2, 3, 4), the brine being capable of flowing through the primary side of each of the at least two heat exchangers, and the primary side of each heat exchanger (2, 3, 4) being cascaded relative to its adjacent heat exchanger (2, 3, 4), wherein each heat exchanger (2, 3, 4) has a secondary side configured such that... The supplied water (c1, c2, c3) evaporates due to heat transfer from the primary side to the secondary side. Alternatively, the circulating water is heated in the secondary loop, and evaporators (15, 16, 17) arranged in this secondary loop cause the supply water (c1, c2, c3) to evaporate. (c) A first pipeline that fluidly connects the geothermal source removal site (a) to the cascaded primary side of these heat exchangers (2, 3, 4), (d) Each of these heat exchangers (2, 3, 4) has a corresponding downstream mineral removal unit (12, 13, 14). (e) A first brine pump (1) is arranged along the main flow direction between the removal site (a) and the primary side of the first heat exchanger (2), thus transporting the brine from the geothermal source to the corresponding cascaded primary sides of these heat exchangers (2, 3, 4) and their corresponding downstream mineral removal units (12, 13, 14). (f) An outflow line fluidly connected to the final mineral removal unit (14) arranged along the main flow direction, wherein the outflow line extends into the geothermal source such that the outlet of the outflow line (b) is at least 100 m, preferably at least 1500 m, and particularly preferably at least 2500 m away from the removal site (a).

2. The geothermal equipment according to claim 1, wherein, The second brine pump (8) is arranged along the main flow direction between the final mineral removal unit (14) and the outlet of the outflow line (b), so that the treated brine is transported to the outlet of the outflow line (b).

3. The geothermal equipment according to claim 1 or 2, wherein, If a secondary loop exists, the corresponding heat exchanger (2, 3, 4) includes pumps (5, 6, 7) for circulating water.

4. The geothermal device according to any one of the preceding claims, wherein, These heat exchangers (2, 3, 4) have corresponding downstream compressors on their secondary side or in the evaporators (15, 16, 17) in these secondary loops, which are configured in their respective cases to compress the generated steam.

5. The geothermal device according to any one of the preceding claims, wherein, There are exactly three cascaded heat exchangers (2, 3, 4) for generating steam, and each of the three heat exchangers (2, 3, 4) has a corresponding downstream mineral removal unit (12, 13, 14).

6. A method of operating a geothermal device according to any one of the preceding claims, the method comprising the following steps: a) The brine is transported from the geothermal source to the primary side of the cascaded heat exchangers (2, 3, 4) by the first brine pump (1), wherein the temperature of the brine at the inlet of the primary side of the first heat exchanger (2) arranged along the main flow direction is in the range of 120°C to 300°C. b) At least some of the heat from the brine is transferred from the primary side of the respective heat exchanger (2, 3, 4). I. The water (c1, c2, c3) supplied to the secondary side is thus evaporated, or II. If a secondary loop exists: Water circulates in the secondary loops of the respective heat exchangers (2, 3, 4), wherein the temperature of the water in the respective secondary loops connected upstream of the evaporators (15, 16, 17) is in the range of 40°C to 195°C, and thus the water (c1, c2, c3) supplied to the evaporators (15, 16, 17) is evaporated. c) Minerals are removed by means of mineral removal units (12, 13, 14) connected downstream of the respective heat exchanger, and d) The treated brine is transported from the outlet of the final mineral removal unit (14) arranged along the main flow direction to the outlet of the outflow line (b), wherein the temperature at the outlet of the outflow line (b) is in the range of 35°C to 115°C.

7. The method of operating a geothermal device according to claim 6, wherein, The temperature of the brine at the inlet of the primary side of the first heat exchanger (2) arranged along the main flow direction is in the range of 120°C to 200°C, preferably in the range of 140°C to 180°C, and the temperature of the brine at the outlet of the primary side of the first heat exchanger (2) is in the range of 105°C to 155°C.

8. The method of operating a geothermal device according to claim 6 or 7, wherein, The temperature of the brine at the inlet of the primary side of the second heat exchanger (3) arranged along the main flow direction is in the range of 105°C to 155°C, and the temperature of the brine at the outlet of the primary side of the second heat exchanger (3) is in the range of 75°C to 120°C.

9. The method of operating a geothermal device according to any one of claims 6 to 8, wherein, The temperature of the brine at the inlet of the primary side of the third heat exchanger (4) arranged along the main flow direction is in the range of 75°C to 120°C, and the temperature of the brine at the outlet of the primary side of the third heat exchanger (4) is in the range of 35°C to 115°C, preferably in the range of 40°C to 85°C, and particularly preferably in the range of 45°C to 55°C.

10. The method of operating a geothermal device according to any one of claims 6 to 9, wherein, There are exactly three heat exchangers (2, 3, 4) for generating steam, and each of the three heat exchangers (2, 3, 4) has a corresponding downstream mineral removal unit (12, 13, 14).

11. The method of operating a geothermal device according to any one of claims 6 to 10, wherein, The first mineral removal unit (12) along the main flow direction separates at least partially, preferably in a major proportion, one of the following substances from the brine for brine purification purposes: Fe, Pb and Al silicates; and at least partially, preferably in a major proportion, one of the following substances from the brine for extraction purposes: Zn, Sr, CaF and Mn.

12. The method of operating a geothermal device according to any one of claims 6 to 11, wherein, The second mineral removal unit (13) along the main flow direction separates at least partially, preferably in a major proportion, one of the following substances from the brine for brine purification purposes: Mg, P and Zn; and at least partially, preferably in a major proportion, one of the following substances from the brine for extraction purposes: Mg, Mn, F, P, Sr and Zn.

13. The method of operating a geothermal device according to any one of claims 6 to 12, wherein, If a third heat exchanger (4) is present, the third mineral removal unit (14) along the main flow direction separates at least partially, preferably in a major proportion, one of the following substances from the brine for extraction purposes: Mn, Sr, F and Ba2+.

14. The method of operating a geothermal device according to claim 13, wherein, Due to the addition of H2SO4, Ba2+ precipitates out of the brine at least partially, and preferably in a major proportion, in the form of barium sulfate.

15. The method of operating a geothermal device according to claim 14, wherein, Precipitated barium sulfate is used as a filler in plastics, as a filler in colloidal substances, as a white pigment for example in coatings, or as a whitening agent.

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