Geothermal water pressurizing, cooling and scale preventing system and method

Abstract

The invention provides a geothermal water pressurizing, cooling and scale preventing system and method. The system comprises a water turbine, a heat exchanger, a production well and a recharge well. The water turbine is provided with an inlet end and an outlet end, and the outlet end of the water turbine is communicated with the recharge well; the water turbine is connected with the direct-current generator and the centrifugal pump through the coupler; the heat exchanger is provided with an inlet end and an outlet end; the outlet end of the heat exchanger is communicated with the inlet end of the water turbine through a pipeline; the inlet end of the heat exchanger is communicated with the production well through a pipeline; the centrifugal pump is provided with an inlet end and an outlet end, and the inlet end of the centrifugal pump is communicated with the outlet end of the heat exchanger through a pipeline; and the outlet end of the centrifugal pump is communicated with the inlet end of the heat exchanger through a pipeline. According to the geothermal anti-scaling process system, the generation amount of calcium carbonate scales of geothermal water side heat exchanger equipment and pipelines is reduced, generation of harmful factors such as blockage is reduced, the overhaul and maintenance cost is reduced, and the operation stability of a geothermal heat supply system is enhanced.

Description

Technical Field

[0001] This invention belongs to the field of geothermal heating, and specifically relates to a geothermal water pressurization, cooling and scale prevention system and method. Background Technology

[0002] Geothermal water scale is classified into calcium carbonate scale, calcium sulfate scale, silicate scale, and iron oxide scale according to its main chemical composition. Calcium carbonate scale is the most common in geothermal water. The dissolution balance of calcium carbonate in geothermal water determines its scaling tendency. The higher the temperature of the geothermal water, the lower the solubility of calcium carbonate; the lower the pressure, the lower the solubility of calcium carbonate. When the solubility decreases, the geothermal water is in a supersaturated state, and geothermal water has a tendency to form scale.

[0003] When high-temperature geothermal water enters the heat exchanger, as the pressure decreases and the flow rate slows down, calcium scale precipitated from the high-temperature geothermal water will deposit on the heat exchange plates. This not only increases the risk of heat exchanger blockage and increases heat exchange resistance loss, but also reduces the heat transfer coefficient due to the increased fouling coefficient, thereby reducing the rated heating power of the geothermal system, affecting the stable operation of the system, and increasing the workload and maintenance costs. Summary of the Invention

[0004] To address the above problems, this invention proposes a geothermal water pressurization, cooling, and scale prevention system, comprising a water turbine, a heat exchanger, a production well, and a reinjection well;

[0005] The water turbine has an inlet end and an outlet end, and the outlet end of the water turbine is connected to the reinjection well; the water turbine is connected to a DC generator and a centrifugal pump through a coupling;

[0006] The heat exchanger has an inlet end and an outlet end; the outlet end of the heat exchanger is connected to the inlet end of the water turbine through a pipeline, and the inlet end of the heat exchanger is connected to the production well through a pipeline;

[0007] The centrifugal pump has an inlet end and an outlet end. The inlet end of the centrifugal pump is connected to the outlet end of the heat exchanger through a pipe; the outlet end of the centrifugal pump is connected to the inlet end of the heat exchanger through a pipe.

[0008] Preferably, it also includes a regulating system for regulating the pressure and temperature of the geothermal water at the inlet of the heat exchanger.

[0009] Preferably, the regulating system includes a pressure regulating system and a temperature regulating system.

[0010] Preferably, the temperature control system includes a first regulating valve and a temperature detection sensor, wherein the first regulating valve is connected to the inlet pipe of the centrifugal pump, and the temperature detection sensor is installed on the inlet pipe of the heat exchanger.

[0011] Preferably, the system further includes a temperature controller, which is electrically connected to the temperature detection sensor and to the first regulating valve.

[0012] Preferably, the pressure regulating system includes a second regulating valve and a pressure detection sensor, wherein the second regulating valve is connected to the inlet pipe of the water turbine; and the pressure detection sensor is installed on the inlet pipe of the heat exchanger.

[0013] Preferably, it further includes a pressure controller, which is electrically connected to a pressure detection sensor and to a second regulating valve.

[0014] A method for pressurizing, cooling, and preventing scale buildup in geothermal water, using the aforementioned equipment, is characterized by comprising the following steps:

[0015] The pressure regulating system is used to increase the pressure of the geothermal water in the inlet pipe of the heat exchanger;

[0016] The temperature control system is used to reduce the temperature of the geothermal water in the inlet pipe of the heat exchanger.

[0017] Preferably, the temperature control system includes a temperature detection sensor and a first regulating valve;

[0018] The temperature sensor detects the temperature of the geothermal water in the inlet pipe of the heat exchanger. When the geothermal water temperature is higher than the set value, the first regulating valve is activated to increase the flow rate of the low-temperature geothermal water in order to maintain the temperature of the geothermal water in the inlet pipe of the heat exchanger at a lower temperature.

[0019] Preferably, the pressure regulating system includes a pressure detection sensor and a second regulating valve;

[0020] The pressure sensor detects the pressure of the geothermal water in the inlet pipe of the heat exchanger. When the geothermal water pressure is lower than the set value, the second regulating valve is closed to increase the pressure, ensuring that the geothermal water pipeline and equipment upstream of the second regulating valve are under higher pressure.

[0021] The beneficial effects of this invention are:

[0022] 1. The geothermal anti-scaling process system proposed in this invention reduces the amount of calcium carbonate scale generated in geothermal water side heat exchangers and pipelines, reduces the occurrence of harmful factors such as blockage, reduces maintenance costs, and enhances the operational stability of the geothermal heating system.

[0023] 2. The geothermal anti-scaling process system proposed in this invention utilizes the geothermal water pressure to drive a centrifugal pump and a DC generator to generate electricity, reducing additional energy consumption and enhancing the operating efficiency of the heating system.

[0024] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 A schematic diagram of the device location is shown in an embodiment of the present invention;

[0027] In the diagram, 1-water turbine, 2-DC generator, 3-centrifugal pump, 4-heat exchanger, 5-production well, 6-recharge well, 7-inverter, 8-distribution cabinet, 9-submersible pump. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] According to the appendix Figure 1 As shown, a geothermal water pressurization, cooling and scale prevention system includes a water turbine 1, a heat exchanger 4, a production well 5 and a reinjection well 6;

[0030] The water turbine 1 has an inlet end and an outlet end. The outlet end of the water turbine 1 is connected to the reinjection well 6. The water turbine 1 is connected to the DC generator 2 and the centrifugal pump 3 through a coupling. The DC generator 2 is connected to the inverter 7. The inverter 7 converts the DC power of the DC generator 2 into AC power, which is then connected to the electrical equipment through the distribution cabinet 8 to realize the use of electrical energy.

[0031] Heat exchanger 4 has an inlet end and an outlet end; the outlet end of heat exchanger 4 is connected to the inlet end of water turbine 1 through a pipeline, and the inlet end of heat exchanger 4 is connected to production well 5 through a pipeline.

[0032] Centrifugal pump 3 has an inlet end and an outlet end. The inlet end of centrifugal pump 3 is connected to the outlet end of heat exchanger 4 through a pipeline. The outlet end of centrifugal pump 3 is connected to the inlet end of heat exchanger 4 through a pipeline. After the low-temperature geothermal water at the outlet end of heat exchanger 4 is pressurized by centrifugal pump, it is mixed with high-temperature geothermal water (geothermal water pumped up from production well 5 using submersible pump 9, which is located below the dynamic water level), thereby reducing the temperature of the geothermal water in the pipeline at the inlet end of heat exchanger 4.

[0033] The invention also includes a regulating system for regulating the pressure and temperature of the geothermal water at the inlet of the heat exchanger 4.

[0034] The regulating system of the present invention includes a pressure regulating system and a temperature regulating system. The pressure regulating system is used to regulate the pressure of the geothermal water at the inlet end of the heat exchanger 4 and inside it, and the temperature regulating system is used to regulate the temperature of the geothermal water at the inlet end of the heat exchanger 4.

[0035] The temperature regulation system of the present invention includes a first regulating valve and a temperature detection sensor. The first regulating valve is connected to the inlet pipe of the centrifugal pump 3, and the temperature detection sensor is installed on the inlet pipe of the heat exchanger 4. When the temperature detection sensor detects that the geothermal water temperature is too high, it controls the first regulating valve to open wider. The centrifugal pump 3 pressurizes the low-temperature geothermal water and mixes it with the high-temperature geothermal water, thereby reducing the temperature of the geothermal water in the inlet pipe of the heat exchanger 4 and preventing scale buildup in the pipe.

[0036] The present invention also includes a temperature controller, which is electrically connected to a temperature detection sensor and a first regulating valve. The temperature is detected by the temperature detection sensor and transmitted to the temperature controller or a central processing unit in real time. When the temperature reaches the threshold set by the temperature controller or the central processing unit, the temperature controller or the central processing unit controls the first regulating valve to work to regulate the amount of geothermal water entering the centrifugal pump 3, thereby regulating the temperature of the geothermal water at the inlet of the heat exchanger 4.

[0037] In conjunction with the embodiments of the present invention, when the temperature detection sensor is a temperature transmitter and the first regulating valve is a flow regulating valve, the detected temperature is transmitted to the temperature controller in real time through the temperature transmitter. When the temperature reaches the threshold set by the temperature controller, the temperature controller controls the flow regulating valve to work to regulate the amount of geothermal water entering the centrifugal pump 3, thereby regulating the temperature of the geothermal water at the inlet of the heat exchanger 4.

[0038] The pressure regulation system of the present invention includes a second regulating valve and a pressure detection sensor. The second regulating valve is connected to the inlet pipe of the water turbine 1; the pressure detection sensor is installed on the inlet pipe of the heat exchanger 4; when the pressure detection sensor senses that the geothermal water pressure is too low, it controls the second regulating valve to close slightly, reducing the water flow at the outlet of the heat exchanger 4 to ensure that the geothermal water pipeline and equipment upstream of the second regulating valve are at a higher pressure; thus achieving scale prevention in the pipeline.

[0039] The present invention also includes a pressure controller, which is electrically connected to a pressure detection sensor and a second regulating valve.

[0040] The pressure is detected by the pressure sensor and transmitted to the pressure controller or central processing unit in real time. When the pressure reaches the threshold set by the pressure controller or central processing unit, the pressure controller or central processing unit controls the pressure regulating valve to adjust the water flow at the outlet of heat exchanger 4, thereby reducing the water flow at the outlet of heat exchanger 4 and ensuring that the geothermal water pipeline and equipment upstream of the pressure regulating valve are at a higher pressure; thus achieving scale prevention in the pipeline.

[0041] In accordance with the embodiments of the present invention, when the pressure detection sensor is a pressure transmitter and the regulating valve is a pressure regulating valve, the pressure detected by the pressure transmitter is transmitted to the pressure regulating valve in real time. When the pressure reaches the threshold set by the pressure controller, the pressure controller controls the pressure regulating valve to work to adjust the water flow at the outlet of heat exchanger 4, thereby reducing the water flow at the outlet of heat exchanger 4 and ensuring that the geothermal water pipeline and equipment upstream of the pressure regulating valve are at a higher pressure.

[0042] A method for pressurizing, cooling, and preventing scale buildup in geothermal water, using the aforementioned equipment, includes the following steps:

[0043] The pressure regulating system is used to increase the pressure of the geothermal water in the inlet pipe of the heat exchanger 4.

[0044] The temperature control system is used to reduce the temperature of the geothermal water in the inlet pipe of the heat exchanger 4.

[0045] Specifically, it prevents scale buildup through the following operation:

[0046] (1) Centrifugal pump 3 pressurizes the low-temperature geothermal water at the outlet of heat exchanger 4 and mixes it with high-temperature geothermal water, thereby reducing the temperature of the geothermal water in the inlet pipe of heat exchanger 4.

[0047] (2) The water turbine 1 reduces the pressure of the geothermal water from high pressure to low pressure or no pressure and then recharges it. At the same time, it outputs shaft power to drive the centrifugal pump 3 to rotate and the DC generator 2 to generate electricity.

[0048] (3) The temperature transmitter detects the temperature of the geothermal water in the inlet pipe of heat exchanger 4. When the geothermal water temperature is higher than the set value, the brake flow regulating valve increases the flow rate of the low-temperature geothermal water to maintain the temperature of the geothermal water in the inlet pipe of heat exchanger 4 at a lower temperature.

[0049] (4) The pressure transmitter detects the pressure of the geothermal water in the inlet pipe of heat exchanger 4. When the geothermal water pressure is lower than the set value, the brake pressure regulating valve is closed to increase the pressure, ensuring that the geothermal water pipeline and equipment upstream of the pressure regulating valve are under higher pressure.

[0050] The following is an engineering example to illustrate the geothermal heating system disclosed herein:

[0051] Basic data for the engineering example: Geothermal production well 5 has a water production rate of 125 cubic meters per hour (m³ / h). 3 / h), water production temperature 80 degrees Celsius (°C), water production pressure 0.5 MPa (gauge pressure); geothermal reinjection well 6 has a reinjection capacity of 125m³. 3 / h, reinjection temperature 40℃, wellhead reinjection pressure 0.1MPa.

[0052] Geothermal heating users utilize floor radiant heating with a heating temperature of 45 / 35℃ (the temperature before the " / " indicates the supply water temperature, and the temperature after the " / " indicates the return water temperature). Two geothermal production wells (5) and two reinjection wells (6) provide heating to users, with a total extraction and injection volume of 250m³. 3 / h.

[0053] The inlet temperature of the geothermal water side of heat exchanger 4 is 80℃, which is the temperature after the geothermal well produced water is mixed with the water pumped by centrifugal pump 3; the inlet pressure of the geothermal water side of heat exchanger 4 is 0.5MPa. The internal pressure drop of heat exchanger 4 is 0.1MPa, the outlet pressure of the geothermal water side of heat exchanger 4 is 0.4MPa, and the outlet temperature is 40℃.

[0054] Water turbine 1 with a flow rate of 250 m³ / h 3 / h, inlet pressure 0.4MPa, outlet pressure 0.1MPa, efficiency 0.75, output power 15.63kW.

[0055] The DC generator 2 is driven by the water turbine 1. The efficiency of converting mechanical energy into electrical energy is 0.98, and the output power of the DC generator 2 is 5.86kW.

[0056] Centrifugal pump 3 is driven by water turbine 1. The motor efficiency of centrifugal pump 3 is 0.9, and the conversion efficiency of centrifugal pump 3 is 0.8. The flow rate of centrifugal pump 3 is 250 m³ / s. 3 The flow rate is 0.65 kW / h, with an inlet pressure of 0.4 MPa, an outlet pressure of 0.5 MPa, and an electrical power consumption of 9.65 kW.

[0057] The inverter 7 in the distribution cabinet 8 is connected to the DC generator 2. The electrical energy generated by the DC generator 2, in addition to being used by the centrifugal pump 3 to pressurize the geothermal water, has a surplus of 5.67kW, which can be used to drive the submersible pump 9 or for other purposes.

[0058] Geothermal water contains a certain amount of Ca 2+ Mg 2+ HCO3 - When plasma passes through a ground heat exchange system, the pressure decreases, CO2 is released, and CaCO3 and MgCO3 precipitate, adhering to equipment and pipelines to form scale.

[0059] Ca(HCO3)2=CaCO3↓+H2O+CO2↑

[0060] Mg(HCO3)2=MgCO3↓+H2O+CO2↑

[0061] The above engineering examples utilize the geothermal anti-scaling process system provided in this disclosure. The submersible pump 9 relies on the pressure-reducing effect of the turbine 1 and its matching pressure regulating valve to increase the pressure of the upstream equipment and pipeline of the turbine 1, maintain the geothermal water in a single-phase state, keep the acidic CO2 gas dissolved in the liquid phase, keep the pH value low, and keep the carbonate minerals in an unsaturated state, thereby inhibiting the formation of calcium carbonate scale.

[0062] The main type of scale formation in geothermal water is calcium carbonate scale. The amount of calcium carbonate deposited increases with increasing temperature. According to the experimental results of calcium carbonate deposition in a certain project, the relationship between calcium carbonate deposition and temperature is 9.6 mg / L - 50℃, 28.89 mg / L - 60℃, 62.59 mg / L - 70℃, 96.29 mg / L - 80℃, and 105.92 mg / L - 90℃. In the above engineering example using the geothermal anti-scaling system provided in this disclosure, the inlet temperature of the geothermal water side of heat exchanger 4 was 60℃, and the calcium carbonate scale deposition was 28.89 mg / L. If the above engineering example used a traditional geothermal heating system, the inlet temperature of the high-temperature side of heat exchanger 4 was 80℃, and the calcium carbonate scale deposition was 96.29 mg / L. However, after using the geothermal anti-scaling system provided in this disclosure, the amount of calcium carbonate scale can be reduced by 70.6%. Therefore, the geothermal anti-scaling process system provided in this disclosure reduces the amount of calcium carbonate scale by lowering the geothermal water inlet temperature of heat exchanger 4, thereby reducing maintenance, enhancing heat exchange efficiency, and improving operational efficiency.

[0063] This disclosure presents a geothermal process system for pressurization, cooling, and scale prevention. This system utilizes a water turbine 1 and its associated pressure regulating valve to increase the pressure of upstream equipment and pipelines. Simultaneously, geothermal water drives the water turbine 1, which in turn rotates a centrifugal pump 3 and generates electricity. The centrifugal pump 3 mixes the low-temperature geothermal water with the high-temperature geothermal water, thereby lowering the temperature of the geothermal water-side equipment and pipelines, thus achieving scale prevention in the geothermal heating system. The reduction in calcium carbonate scale decreases flow resistance, enhances heat exchange efficiency, and weakens the occurrence and development of blockages. Compared to traditional geothermal heating systems, the reduction in calcium carbonate scale lowers operating energy consumption, reduces maintenance workload, decreases downtime for maintenance and corresponding operating costs, enhances the stability of the heat exchange system, and improves the efficiency of geothermal heating projects.

[0064] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A geothermal water pressurization, cooling, and scale prevention system, characterized in that, It includes a water turbine (1), a heat exchanger (4), a production well (5), and a reinjection well (6); The water turbine (1) has an inlet end and an outlet end, and the outlet end of the water turbine (1) is connected to the reinjection well (6); the water turbine (1) is connected to the DC generator (2) and the centrifugal pump (3) through a coupling; The heat exchanger (4) has an inlet end and an outlet end; the outlet end of the heat exchanger (4) is connected to the inlet end of the water turbine (1) through a pipeline, and the inlet end of the heat exchanger (4) is connected to the production well (5) through a pipeline; The centrifugal pump (3) has an inlet end and an outlet end. The inlet end of the centrifugal pump (3) is connected to the outlet end of the heat exchanger (4) through a pipe. The outlet end of the centrifugal pump (3) is connected to the inlet end of the heat exchanger (4) through a pipe.

2. The geothermal water pressurization, cooling, and scale prevention system according to claim 1, characterized in that, It also includes a regulating system for regulating the pressure and temperature of the geothermal water at the inlet of the heat exchanger (4).

3. The geothermal water pressurization, cooling, and scale prevention system according to claim 2, characterized in that, The regulation system includes a pressure regulation system and a temperature regulation system.

4. The geothermal water pressurization, cooling, and scale prevention system according to claim 3, characterized in that, The temperature control system includes a first regulating valve and a temperature detection sensor. The first regulating valve is connected to the inlet pipe of the centrifugal pump (3), and the temperature detection sensor is installed on the inlet pipe of the heat exchanger (4).

5. The geothermal water pressurization, cooling, and scale prevention system according to claim 4, characterized in that, It also includes a temperature controller, which is electrically connected to the temperature detection sensor and to the first regulating valve.

6. The geothermal water pressurization, cooling, and scale prevention system according to claim 3, characterized in that, The pressure regulation system includes a second regulating valve and a pressure detection sensor. The second regulating valve is connected to the inlet pipe of the water turbine (1). The pressure detection sensor is installed on the inlet pipe of the heat exchanger (4).

7. A geothermal water pressurization, cooling, and scale prevention system according to claim 6, characterized in that, It also includes a pressure controller, which is electrically connected to a pressure detection sensor and to a second regulating valve.

8. A method for pressurizing, cooling, and preventing scale buildup in geothermal water, using the equipment described in any one of claims 3-7, characterized in that... Includes the following steps: The pressure regulating system is used to increase the pressure of the geothermal water in the inlet pipe of the heat exchanger (4); The temperature control system is used to reduce the temperature of the geothermal water in the inlet pipe of the heat exchanger (4).

9. A method for pressurizing, cooling, and preventing scale buildup in geothermal water according to claim 8, characterized in that, The temperature control system includes a temperature detection sensor and a first regulating valve; The temperature sensor detects the temperature of the geothermal water in the inlet pipe of the heat exchanger (4). When the geothermal water temperature is higher than the set value, the first regulating valve is braked to increase the flow rate of the low-temperature geothermal water in order to maintain the temperature of the geothermal water in the inlet pipe of the heat exchanger (4) at a lower temperature.

10. A method for pressurizing, cooling, and preventing scale formation in geothermal water according to claim 8, characterized in that, The pressure regulation system includes a pressure detection sensor and a second regulating valve; The pressure sensor detects the pressure of the geothermal water in the inlet pipe of the heat exchanger (4). When the geothermal water pressure is lower than the set value, the second regulating valve is closed to increase the pressure, ensuring that the geothermal water pipeline and equipment upstream of the second regulating valve are under higher pressure.

Images