Geothermal station zero discharge system design method

Abstract

The invention relates to the technical field of terrestrial heat exploitation, and discloses a terrestrial heat station zero discharge system design method which comprises the following steps: acquiring a heat load heat change curve in a heat interval to design a heat exploitation dynamic adjustment framework; according to the configuration, a plurality of heat exchangers connected in series and / or in parallel are arranged through a distributed or centralized heat supply path according to all heat consumption load requirements in a heat consumption interval, and the heat exchangers are provided with multiple heat taking strategies to dynamically adjust the heat utilization rate of the heat exchangers; estimating a geothermal well of a corresponding energy level matched with a total heat utilization value of the heat utilization interval in a preset heat utilization period; a temperature detection array is configured to monitor the operation condition of a heat exchanger and the actual heat supply temperature of a heat load end in real time, and the exploitation quantity of a geothermal well and the operation mode of the heat exchanger are dynamically adjusted based on a preset heat supply temperature interval, so that the actual heat supply temperature of the heat load end is accurately controlled within the preset heat supply temperature interval. And all heat consumption load requirements in the heat consumption interval are met.

Description

Technical Field

[0001] This invention relates to the field of geothermal extraction technology, specifically to a design method for a zero-exhaust system for geothermal stations. Background Technology

[0002] In the current development and utilization of geothermal resources, the requirements for heat exchange efficiency and temperature control accuracy in scenarios such as geothermal heating and industrial heat use are increasingly demanding. However, traditional geothermal heat exchange systems still face the following pressing technical problems: existing systems largely rely on manual valve adjustment to control the cold source flow rate or heat exchange area, lacking real-time monitoring and intelligent control mechanisms. On the one hand, monitoring only the total heating temperature cannot pinpoint heat exchange anomalies in individual heat exchange pipes, leading to lag in regulation. On the other hand, the regulation strategy is singular (such as simply increasing or decreasing the cold source flow rate), failing to dynamically adapt to the deviation between the actual heating temperature and user demand, easily resulting in heating temperature fluctuations (often > ±2℃), making it difficult to meet the temperature stability requirements of residential heating and precision industrial heat use. Therefore, there is an urgent need to design a geothermal cascade utilization system capable of accurate monitoring, dynamic control, and adaptability to different heat load requirements to solve the problem of waste in traditional geothermal extraction. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a design method for a zero-exhaust system of a geothermal station to solve the technical problems mentioned in the prior art.

[0004] A design method for a zero-emission geothermal station system includes the following steps: The heat load demand of all heat loads within a certain heat demand range is obtained to calculate the heat load at a preset time point. Based on the heat load at multiple preset time points obtained within a continuous detection period, a heat load change curve within the preset detection range is generated. A dynamic adjustment architecture for thermal mining is designed based on the heat load change curve. The dynamic adjustment architecture for thermal mining is configured as follows: Cascaded heat exchange and heat utilization: According to the heat load demand within the heat use zone, multiple heat exchangers are set up in series and / or in parallel using a distributed or centralized heating path. The fluids on the heat source side and cold source side of the multiple heat exchangers flow in an S-shape or in a stepped manner, so as to configure a variety of different heat extraction strategies to dynamically adjust the heat utilization rate of the heat exchangers according to the heat load heat change curve. Geothermal extraction and reinjection: Based on the heat load change curve within a preset detection range, the total heat utilization value of the heat utilization range within a preset heat utilization cycle is estimated, and based on the total heat utilization value of the heat utilization range within the preset heat utilization cycle, a geothermal well of the corresponding energy level is selected for construction; the geothermal well extraction end is configured with several heat source input pipes according to any one or more heat extraction strategies and connected to the heat source side of the heat exchanger, so that the multiple heat exchangers are synchronously or sequentially connected to geothermal energy along the heat source flow direction; the geothermal well reinjection end is connected to the cold output port of each heat exchanger through cold output pipes; a solid-liquid separator is installed on the heat source input pipe and / or the cold output pipe to filter out impurities carried in the heat source; Intelligent monitoring and control: A temperature detection array is configured, comprising a first temperature sensor located at the heat output end of several heat exchange pipes built into each heat exchanger to collect first temperature information, and a second temperature sensor on the heat source output pipe connected to the heat load end along the heating path to collect second temperature information; the temperature detection array monitors the operating condition of the heat exchanger and the actual heating temperature at the heat load end in real time, and dynamically adjusts the extraction rate of the geothermal well and the operating mode of the heat exchanger based on a preset heating temperature range, so as to accurately control the actual heating temperature at the heat load end within the preset heating temperature range, so as to meet the heating load demand of all heat loads within the heating range.

[0005] Optionally, the heat extraction strategy of the heat exchanger is set as follows: When the heat source sides of multiple heat exchangers are arranged in a stepped manner side by side, the operating modes of the heat exchangers include: Independent heat exchange mode: The cold source sides of multiple heat exchangers are arranged in a stepped manner to achieve single heat extraction; Circulating heat exchange mode: The cold source sides of multiple heat exchangers are connected in an S-shape to achieve cascaded heat extraction from the cold source.

[0006] Optionally, the heat extraction strategy of the heat exchanger is set as follows: When the heat source sides of multiple heat exchangers are connected in an S-shape, the operating modes of the heat exchangers include: Independent heat exchange mode: The cold source sides of multiple heat exchangers are arranged in a stepped manner to realize the cascade utilization of heat source; Circulating heat exchange mode: The cold source sides of multiple heat exchangers are connected in an S-shape to achieve single heat extraction.

[0007] Optionally, the method for dynamically adjusting the geothermal well extraction rate based on real-time monitoring of the heat exchanger's operating conditions and the actual heating temperature at the heat load end using the temperature detection array, and based on a preset heating temperature range, is configured as follows: Based on the heat exchange efficiency of the heat exchanger under any heat extraction strategy, the utilization rate of geothermal well extraction volume per unit flow rate is calculated to generate a geothermal well extraction volume-heat exchange efficiency comparison table. A geothermal extraction dynamic adjustment model is constructed based on the geothermal well extraction volume-heat exchange efficiency comparison table. The geothermal extraction dynamic adjustment model uses the difference calculation method to calculate the deviation value ΔT between the second temperature information and the preset heating temperature range. When T 总 ≥T max When, ΔT=T 总 -T max ; When T 总 ≤T min When, ΔT=T 总 -T min ; Among them, T 总 For the second temperature information, the preset heating temperature range is [T]. min T max ]; When ΔT > 0, the heat supply is excessive. The geothermal extraction dynamic adjustment model reduces the current extraction volume of the geothermal well by several units based on the geothermal well extraction volume-heat exchange efficiency comparison table, so that ΔT approaches 0. When ΔT < 0, the heating supply is insufficient. The geothermal extraction dynamic adjustment model increases the current extraction volume of the geothermal well by several units based on the geothermal well extraction volume-heat exchange efficiency comparison table, so that ΔT approaches 0. When ΔT=0, the heat demand is met, and the geothermal extraction dynamic adjustment model maintains the current extraction volume of the geothermal well.

[0008] Optionally, the method for dynamically adjusting the operating mode of the heat exchanger based on real-time monitoring of the heat exchanger's operating conditions and the actual heating temperature at the heat load end by the temperature detection array, and based on a preset heating temperature range, is configured as follows: The geothermal extraction dynamic adjustment model calculates the temperature regulation parameter ΔT corresponding to the heat exchange pipes of each heat exchanger based on the deviation value ΔT between the second temperature information and the preset heating temperature range. i ; ΔT i =|ΔT|-T i ; Among them, T i This refers to the first temperature information of the heat exchange pipes built into the i-th heat exchanger and in operating condition. 1, 2, ..., n; If there exists at least one ΔT i If ΔT = 0, it is determined that the output temperature of part of the heat exchange pipes is adjusted. Specifically, when ΔT > 0, any set of ΔT is turned off.i =0 and is currently in the open state of the heat exchange pipe; when ΔT<0, then any set of ΔT is opened. i If the heat exchange pipe is ΔT = 0 and currently in a closed state, and all ΔT values ​​are detected at this time... i If all heat exchange pipes with a value of 0 are in the open state, then the opening degree of the proportional valve on the cold source input side of the heat exchanger is adjusted sequentially according to the heat source flow direction and the preset adjustment rule. The preset adjustment rule is set to reduce the opening degree of the proportional valve according to the preset unit quantity and adjustment frequency. If all ΔT i If the value is not equal to 0, then it is determined that the output temperature of all heat exchange pipes should be adjusted sequentially. In this case, T is selected first. i Closest to ΔT i The heat exchange pipes are regulated by calculating |T i -ΔT i The minimum value of | is determined; then, the filtered T is adjusted according to the sign of the current ΔT. i Closest to ΔT i The proportional valve opening degree of the heat exchanger in the heat exchange pipeline is determined by the following: when ΔT < 0, the proportional valve opening degree of the corresponding heat exchanger is reduced according to the preset adjustment rule until the proportional valve is fully closed; when ΔT > 0, the proportional valve opening degree of the heat exchanger is increased according to the preset adjustment rule until the proportional valve is fully open.

[0009] Optionally, when dynamically adjusting the operating mode of the heat exchanger, if, within a preset control cycle, ΔT is detected to still not approach 0 after any heat exchange pipe or heat exchanger has been continuously controlled several times, the control object is automatically switched to the next set of ΔT values. i The closest heat exchange pipe is used to avoid the accumulation of deviations caused by the failure of a single heat exchange pipe control.

[0010] Optionally, the opening degree of the proportional valve is preset to a unit quantity of 5%-10% / time during the adjustment phase.

[0011] Optionally, the solid-liquid separator includes: The transfer station has a hollow internal structure, with water inlets and outlets on its outer perimeter and a slag discharge outlet at the bottom. A filter element is installed in the transfer station and forms an annular spiral filtration channel along its outer periphery to connect the inlet and outlet of the transfer station. The outlet of the transfer station extends into the filter element through a pipe that passes through the annular spiral filtration channel. The slag discharge unit has its feed end connected to the slag discharge port, and an electronic valve is installed at the slag discharge port. The electronic valve is configured to open for a corresponding time according to the discharge rate of the slag discharge port to discharge the impurities filtered by the filter element when the volume of impurities obtained by the geothermal fluid filtering within a preset detection cycle approaches the bottom of the filter element.

[0012] Optionally, the design method of the heat exchanger is set as follows: Detect the water composition and fluid temperature of geothermal wells; The distance between the geothermal well extraction end and the reinjection end is calculated according to the design drawings, and the optimal design position of the heat exchanger on the connecting pipeline between the geothermal well extraction end and the reinjection end is determined based on the density of the heat load user end. The optimal design position is configured such that the density of the heat load user end is greater than 70%-90%, thereby constructing the heat source transmission pipeline. The heat loss rate generated during heat source transportation is obtained based on the length of the heat source transportation pipeline and environmental influencing factors. The heat source input end temperature of the heat exchanger is calculated based on the heat loss rate and the fluid temperature of the geothermal well. Then, the total heat exchange efficiency of the heat exchanger is obtained based on the temperature difference between the heat source input end temperature of the heat exchanger and the heat load demand. The number, length, and flow area of ​​heat exchange pipes are designed based on the overall heat exchange efficiency of the heat exchanger. The material of the heat exchange pipe is selected based on the water quality composition and heat exchange efficiency of the geothermal well, and its corrosion resistance requirement is set to be greater than the preset service life.

[0013] Optionally, based on the solid thermal bridge effect, multiple heat exchangers are integrated into a vacuum-insulated cavity, and the vacuum level in the vacuum-insulated cavity must ensure that the heat loss of the heat exchangers is less than 40% under different operating conditions.

[0014] The beneficial effects that this invention can produce include: 1. The present invention provides a design method for a zero-exhaust geothermal station system. Based on the load demand of the heating zone, it employs distributed or centralized heating paths to set up series and / or parallel heat exchangers, and configures various heat extraction strategies through S-shaped, stepped, or other fluid flow path designs. For example, when the heat source side of the heat exchangers is arranged in a stepped parallel configuration, an independent heat exchange mode can be switched to achieve single heat extraction, or a circulating heat exchange mode can be used to achieve tiered heat extraction from the cold source. When the heat source side is connected along an S-shape, different modes can be used to achieve tiered utilization of the heat source or single heat extraction. This tiered design can accurately allocate geothermal energy for heat loads with different temperature requirements (such as heating, industrial heat, domestic hot water, etc.), avoiding energy waste caused by directly using high-grade geothermal energy in low-demand scenarios, and increasing geothermal utilization rate by more than 30%.

[0015] 2. The system designed in this invention constructs a complete closed loop consisting of "geothermal well extraction end - heat source input pipeline - heat exchanger - cold output pipeline - geothermal well reinjection end," reinjecting all the geothermal fluid, which has cooled down after heat exchange, back into the geothermal well without any wastewater discharge. This design avoids the pollution of surrounding water bodies and soil caused by wastewater discharge from traditional geothermal systems, while also replenishing underground hot water resources, maintaining the pressure balance of underground thermal reservoirs, and achieving the sustainable development and utilization of geothermal resources, meeting the environmental protection requirements under the dual-carbon target. Simultaneously, the solid-liquid separators installed on the heat source input pipeline and / or cold output pipeline utilize centrifugal force to achieve preliminary solid-liquid separation through the annular spiral filtration channel of the transfer station, and then precisely filter out solid particulate impurities carried in the heat source through the filter element. Furthermore, the electronic valve of the slag discharge unit can intelligently control the slag discharge time according to the volume of impurities and the discharge rate. Combined with image measurement method, it can monitor whether there is heat source discharge, avoid impurities clogging the valve group and affecting the operation of the heat exchanger, and prevent impurities from backfilling into the geothermal well reinjection end, causing blockage and pollution of the thermal reservoir, thus ensuring the long-term stable operation of the geothermal well.

[0016] 3. The system designed in this invention is equipped with a dynamic adjustment mechanism to accurately match heat load fluctuations. Based on temperature detection array data, it achieves dual dynamic regulation through a geothermal extraction dynamic adjustment model: on the one hand, according to the deviation value ΔT between the second temperature information and the preset heating temperature range, combined with the geothermal well extraction rate-heat exchange efficiency comparison table, the geothermal well extraction rate is adjusted to ensure that the geothermal supply is basically matched with the load demand; on the other hand, the temperature regulation parameter ΔT of each heat exchange pipe is calculated. i The system adjusts the on / off status of heat exchange pipes or the opening / closing degree of the proportional valve on the cold source input side of the heat exchanger (by 5%-10% each time), and automatically switches when a single control object fails, achieving precise control of the actual heating temperature at the heat load end within a preset range. This dynamic control mechanism can flexibly adapt to heat load fluctuations in different heating areas (such as residential areas, industrial areas, and commercial buildings) at different times (such as day and night, and seasons), avoiding problems of excessive or insufficient heating. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the system structure of the present invention; Figure 2 This is a schematic diagram of a heat extraction strategy for the heat exchanger in this invention; Figure 3 This is a schematic diagram of another heat extraction strategy for the heat exchanger in this invention; In the diagram: 1. Heat exchanger, 2. Heat exchange pipe, 3. Heat source input pipe, 4. Cold source input pipe, 5. Heat output pipe, 6. Cold output pipe, 7. First temperature sensor, 8. Second temperature sensor, 9. Proportional valve, 10. Electronic valve, 11. Vacuum insulated cavity, 12. Transfer station, 13. Filter element, 14. Slag discharge unit. Detailed Implementation

[0018] 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, and 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.

[0019] This invention provides a design method for a zero-exhaust system of a geothermal station, used to design a system such as... Figure 1-3 The system shown is a geothermal cascade utilization system capable of precise monitoring, dynamic control, and adaptation to different heat load requirements. The system includes multiple heat exchangers 1 built into a vacuum-insulated cavity 11. The heat source input end of the heat exchanger 1 is connected to the extraction end of the geothermal well via a heat source input pipe 3, and the heat source output end of the heat exchanger 1 is connected to the reinjection end of the geothermal well via a cold output pipe 6. The system constructs a complete closed loop of "geothermal well extraction end - heat source input pipe 3 - heat exchanger 1 - cold output pipe 6 - geothermal well reinjection end," reinjecting all the geothermal fluid, which has cooled after heat exchange, back into the geothermal well without any wastewater discharge. This design avoids the pollution of surrounding water bodies and soil caused by wastewater discharge from traditional geothermal systems, while also replenishing underground hot water resources, maintaining the pressure balance of underground thermal reservoirs, and achieving sustainable development and utilization of geothermal resources, meeting the environmental protection requirements under the dual-carbon target. The cold source input end of heat exchanger 1 is connected to cold source input pipe 4, and the cold source output end of heat exchanger 1 is connected to heat output pipe 5. Each heat exchanger 1 has multiple heat exchange pipes 2, and a first temperature detection sensor 7 is installed at the heat output end of each heat exchange pipe 2. A second temperature detection sensor 8 is installed on the heat source output pipe. A temperature detection array is constructed using the second temperature detection sensor 8 and multiple first temperature detection sensors 7 to monitor the operating conditions of heat exchanger 1 and the actual heating temperature at the heat load end in real time, so as to dynamically adjust the system heating temperature according to different heat load requirements. The method specifically includes the following steps: The heat load demand of all heat loads within a certain heat demand range is obtained to calculate the heat load at preset time points. Based on the heat load at multiple preset time points obtained within a continuous detection cycle, a heat load change curve within the preset detection range is generated. A dynamic adjustment architecture for thermal mining is designed based on the heat load change curve. The dynamic adjustment architecture for thermal mining is configured as follows: Cascade heat exchange and heat utilization: According to the heat load demand of all heat loads in the heat use area, multiple heat exchangers 1 are set up in series and / or in parallel using distributed or centralized heating paths. The fluids on the heat source side and cold source side of the multiple heat exchangers 1 flow in an S-shape or in a stepped manner, so as to configure a variety of different heat extraction strategies to dynamically adjust the heat utilization rate of heat exchangers 1 according to the heat load heat consumption change curve. Geothermal extraction and reinjection: The total heat utilization value of the heat utilization range within a preset heat utilization cycle is estimated based on the heat load heat utilization change curve within a preset detection range, and the corresponding energy level of the geothermal well is selected for construction based on the total heat utilization value of the heat utilization range within the preset heat utilization cycle; the geothermal well extraction end is configured with several heat source input pipes 3 according to any one or more heat extraction strategies and connected to the heat source side of the heat exchanger 1, so that multiple heat exchangers 1 are connected to geothermal energy synchronously or sequentially along the heat source flow direction; the geothermal well reinjection end is connected to the cold output port of each heat exchanger 1 through cold output pipes 6; solid-liquid separators are installed on the heat source input pipes 3 and / or cold output pipes 6 to filter out impurities carried in the heat source; Intelligent monitoring and control: A temperature detection array is configured, including a first temperature sensor 7 located at the heat output end of several heat exchange pipes 2 built into each heat exchanger 1 to collect first temperature information, and a second temperature sensor 8 located on the heat source output pipe connected to the heat load end along the heating path to collect second temperature information; the temperature detection array monitors the operating condition of the heat exchanger 1 and the actual heating temperature at the heat load end in real time, and dynamically adjusts the extraction rate of the geothermal well and the operating mode of the heat exchanger 1 based on a preset heating temperature range, so as to accurately control the actual heating temperature at the heat load end within the preset heating temperature range, so as to meet the heating load demand of all heat loads within the heating range.

[0020] In the above, the multiple heat exchangers 1 in the system adopt a modular layout and support independent heat exchange mode operation. When a heat exchanger fails, it can be shut down for maintenance, while the other heat exchangers can still work normally without stopping the entire system. This significantly reduces the heating interruption time caused by equipment maintenance, reduces the impact on users with heat load, simplifies the maintenance process, and reduces maintenance manpower and time costs.

[0021] As one embodiment of the present invention, such as Figure 2 As shown, the heat extraction strategy of heat exchanger 1 is set as follows: when multiple heat exchangers 1 are arranged side by side in a stepped manner on their heat source sides, the operating modes of heat exchanger 1 include: Independent heat exchange mode: Multiple heat exchangers 1 are arranged side by side in a stepped manner on the cold source side to achieve single heat extraction; Circulating heat exchange mode: The cold source sides of multiple heat exchangers 1 are connected in an S-shape to realize cascade heat extraction from the cold source.

[0022] As another embodiment of the present invention, such as Figure 3 As shown, the heat extraction strategy of heat exchanger 1 is set as follows: when the heat source sides of multiple heat exchangers 1 are connected in an S-shape, the operating modes of heat exchanger 1 include: Independent heat exchange mode: The cold source sides of multiple heat exchangers 1 are arranged in a stepped manner to realize the cascade utilization of heat source; Circulating heat exchange mode: Multiple heat exchangers 1 are connected along an S-shape on the cold source side to achieve single heat extraction.

[0023] In the above, the independent heat exchange mode and the circulating heat exchange mode connect the heat source side and cold source side of two adjacent heat exchangers 1 through pre-designed connecting pipes, and configure corresponding control valves on their connecting pipes to switch to different heat exchange modes according to heating demand. This tiered design can accurately allocate geothermal energy for heat loads with different temperature requirements (such as heating, industrial heat, domestic hot water, etc.), avoid the energy waste caused by high-grade geothermal energy being directly used in low-demand scenarios, and improve the geothermal utilization rate by more than 30%.

[0024] Furthermore, the method for dynamically adjusting the geothermal well extraction rate based on the real-time monitoring of the operating conditions of heat exchanger 1 and the actual heating temperature at the heat load end by the temperature detection array, and based on the preset heating temperature range, is as follows: the utilization rate of geothermal well extraction rate per unit flow is calculated based on the heat exchange efficiency of heat exchanger 1 under any heat extraction strategy, generating a geothermal well extraction rate-heat exchange efficiency comparison table, and a geothermal extraction dynamic adjustment model is constructed based on the geothermal well extraction rate-heat exchange efficiency comparison table. The geothermal extraction dynamic adjustment model uses the difference calculation method to calculate the deviation value ΔT between the second temperature information and the preset heating temperature range. When T 总 ≥T max When, ΔT=T 总 -T max ; When T 总 ≤T min When, ΔT=T 总 -T min ; Among them, T 总 For the second temperature information, the preset heating temperature range is [T]. min T max ]; When ΔT > 0, the heat supply is excessive. The geothermal extraction dynamic adjustment model reduces the current extraction volume of the geothermal well by several units based on the geothermal well extraction volume-heat exchange efficiency comparison table, so that ΔT approaches 0. When ΔT < 0, the heating supply is insufficient. The geothermal extraction dynamic adjustment model increases the current extraction volume of the geothermal well by several units based on the geothermal well extraction volume-heat exchange efficiency comparison table, so that ΔT approaches 0. When ΔT=0, the heat demand is met, and the geothermal extraction dynamic adjustment model maintains the current extraction volume of the geothermal well.

[0025] Furthermore, the method for dynamically adjusting the operating mode of heat exchanger 1 based on the real-time monitoring of the operating conditions of heat exchanger 1 by the temperature detection array and the actual heating temperature at the heat load end, and based on the preset heating temperature range, is set as follows: the geothermal extraction dynamic adjustment model calculates the temperature regulation parameter ΔT corresponding to the heat exchange pipe 2 of each heat exchanger 1 based on the deviation value ΔT between the second temperature information and the preset heating temperature range. i ; ΔT i =|ΔT|-T i ; Among them, T i The first temperature information of the heat exchange pipe 2 built into the i-th heat exchanger 1 and in operating condition, i 1, 2, ..., n; If there exists at least one ΔT i If ΔT = 0, it is determined that the output temperature of part of the heat exchange pipe 2 is adjusted. Specifically, when ΔT > 0, any set of ΔT is turned off. i Heat exchanger pipe 2 is currently open when ΔT = 0; when ΔT < 0, any set of ΔT is opened. i Heat exchanger pipe 2, where ΔT = 0 and is currently closed, if all ΔT values ​​are detected at this time... i If all heat exchange pipes 2 with =0 are in the open state, then the opening degree of the proportional valve 9 on the cold source input side of heat exchanger 1 is adjusted sequentially according to the heat source flow direction and the preset adjustment rule. The preset adjustment rule is set to reduce the opening degree of the proportional valve 9 according to the preset unit quantity and adjustment frequency. If all ΔT i If the value is not equal to 0, then it is determined that the output temperature of all heat exchange pipes 2 should be adjusted sequentially. In this case, T is selected first. i Closest to ΔT i The heat exchange pipe 2 is adjusted by calculating |T i -ΔT i The minimum value of | is determined; then, the filtered T is adjusted according to the sign of the current ΔT. i Closest to ΔT i The opening degree of the proportional valve 9 of the heat exchanger 1 in the heat exchange pipe 2 is determined as follows: when ΔT < 0, the opening degree of the proportional valve 9 corresponding to the heat exchanger 1 is reduced according to a preset adjustment rule until the proportional valve 9 is fully closed; when ΔT > 0, the opening degree of the proportional valve 9 of the heat exchanger 1 is increased according to a preset adjustment rule until the proportional valve 9 is fully open. The preset unit quantity for the opening degree of the proportional valve 9 during the adjustment phase is 5%-10% per cycle.

[0026] In the above-described dynamic adjustment of the operating mode of heat exchanger 1, if, within a preset control cycle, ΔT is detected to be not close to 0 after any heat exchange pipe 2 or heat exchanger 1 has been continuously controlled several times, the control object will be automatically switched to the next set of ΔT values. i The closest heat exchange pipe 2 is used to avoid the accumulation of deviations caused by the failure of the control of a single heat exchange pipe 2.

[0027] Furthermore, the solid-liquid separator includes a transfer station 12, a filter element 13, and a slag discharge unit 14. The transfer station 12 has a hollow internal structure with an inlet and an outlet on its outer periphery and a slag discharge port at the bottom. The filter element 13 is located inside the transfer station 12 and forms an annular spiral filtration channel along its outer periphery to connect the inlet and outlet of the transfer station 12. The outlet of the transfer station 12 extends into the filter element 13 through a pipe that passes through the annular spiral filtration channel. The feed end of the slag discharge unit 14 is connected to the slag discharge port, and an electronic valve 10 is installed at the slag discharge port. The electronic valve 10 is configured to open for a corresponding time according to the discharge rate of the slag discharge port when the volume of impurities filtered by the geothermal fluid within a preset detection cycle approaches the bottom of the filter element 13, so as to discharge the impurities filtered by the filter element 13. Specifically, when the heat source fluid flows through the heat source input pipe 3 and / or the cold output pipe 6, it first flows into the annular spiral filter channel inside the transfer station 12 through the inlet of the transfer station 12, so that the solid and liquid are initially separated under the action of centrifugal force, which facilitates the solid particulate impurities to fall into the bottom of the filter element 13. Then, the heat source fluid flows into the inner side of the filter element 13 through the mesh on the surface of the filter element 13, and is discharged from the outlet of the transfer station 12 through the pipe, thereby realizing the removal of impurities from the heat source fluid, avoiding impurities from clogging the valve group, affecting the normal operation of the heat exchanger 1, and preventing impurities from backfilling into the reinjection end of the geothermal well and causing blockage. The slag discharge unit 14 is configured as a diaphragm pump, with its feed end connected to the slag discharge port via a pipeline, and its discharge end equipped with a collection trough. To ensure the solid-liquid separator operates continuously during slag discharge, and to prevent uneven mixing of impurities in the heat source fluid leading to inconsistent impurity volumes within a preset detection cycle, which could cause heat source fluid to be discharged when the electronic valve 10 opens at the same time each time, an alarm mechanism is implemented. This mechanism uses image measurement to determine the impurity content in the water flowing from the diaphragm pump's discharge end. When the impurity content in the water is detected to be below a preset value, heat source discharge is detected. At this point, the electronic valve 10 is controlled to close the slag discharge port and stop the diaphragm pump, ending the current slag discharge operation. If heat source discharge is detected during two or more consecutive slag discharge operations, an alarm unit (such as a buzzer) is triggered to issue an alarm signal, prompting staff to check if the heating supply is normal.

[0028] Furthermore, the design method for heat exchanger 1 is as follows: The water quality composition and fluid temperature of the geothermal well are surveyed; the distance between the geothermal well's extraction end and reinjection end is calculated according to the design drawings, and the optimal design position of heat exchanger 1 on the connecting pipeline between the geothermal well's extraction end and reinjection end is determined based on the density of the heat load user ends. The optimal design position is configured such that the density of the heat load user ends is greater than 70%-90%, thereby constructing the heat source transmission pipeline; the heat loss rate generated during heat source transmission is obtained based on the length of the heat source transmission pipeline and environmental influencing factors, and the heat source input end temperature of heat exchanger 1 is calculated based on the heat loss rate and the fluid temperature of the geothermal well; then, the total heat exchange efficiency of heat exchanger 1 is obtained based on the temperature difference between the heat source input end temperature of heat exchanger 1 and the heat load demand; the number, length, and flow area of ​​heat exchange pipes 2 are designed based on the total heat exchange efficiency of heat exchanger 1; the material of heat exchange pipes 2 is comprehensively selected based on the water quality composition and heat exchange efficiency of the geothermal well, and its corrosion resistance requirement is set to be greater than the preset service life.

[0029] Furthermore, based on the solid thermal bridge effect, multiple heat exchangers 1 are integrated into a vacuum-insulated cavity 11. The vacuum environment blocks heat conduction and convection heat transfer paths, retaining only a small amount of radiative heat transfer loss. The vacuum level within the vacuum-insulated cavity 11 must ensure that the heat loss of the heat exchangers 1 is less than 40% under different operating conditions, effectively reducing ineffective consumption of geothermal energy during transmission and heat exchange, and allowing extracted geothermal energy to be converted into usable thermal energy more efficiently.

Claims

1. A design method for a zero-exhaust system of a geothermal station, characterized in that, Includes the following steps: The heat load demand of all heat loads within a certain heat demand range is obtained to calculate the heat load at a preset time point. Based on the heat load at multiple preset time points obtained within a continuous detection period, a heat load change curve within the preset detection range is generated. A dynamic adjustment architecture for thermal mining is designed based on the heat load change curve. The dynamic adjustment architecture for thermal mining is configured as follows: Cascaded heat exchange and heat utilization: According to the heat load demand within the heat use zone, multiple heat exchangers are set up in series and / or in parallel using a distributed or centralized heating path. The fluids on the heat source side and cold source side of the multiple heat exchangers flow in an S-shape or in a stepped manner, so as to configure a variety of different heat extraction strategies to dynamically adjust the heat utilization rate of the heat exchangers according to the heat load heat change curve. Geothermal extraction and reinjection: Based on the heat load change curve within a preset detection range, the total heat utilization value of the heat utilization range within a preset heat utilization cycle is estimated, and based on the total heat utilization value of the heat utilization range within the preset heat utilization cycle, a geothermal well of the corresponding energy level is selected for construction; the geothermal well extraction end is configured with several heat source input pipes according to any one or more heat extraction strategies and connected to the heat source side of the heat exchanger, so that the multiple heat exchangers are synchronously or sequentially connected to geothermal energy along the heat source flow direction; the geothermal well reinjection end is connected to the cold output port of each heat exchanger through cold output pipes; a solid-liquid separator is installed on the heat source input pipe and / or the cold output pipe to filter out impurities carried in the heat source; Intelligent monitoring and control: A temperature detection array is configured, comprising a first temperature sensor located at the heat output end of several heat exchange pipes built into each heat exchanger to collect first temperature information, and a second temperature sensor on the heat source output pipe connected to the heat load end along the heating path to collect second temperature information; the temperature detection array monitors the operating condition of the heat exchanger and the actual heating temperature at the heat load end in real time, and dynamically adjusts the extraction rate of the geothermal well and the operating mode of the heat exchanger based on a preset heating temperature range, so as to accurately control the actual heating temperature at the heat load end within the preset heating temperature range, so as to meet the heating load demand of all heat loads within the heating range.

2. The design method for a zero-exhaust system of a geothermal station according to claim 1, characterized in that, The heat extraction strategy of the heat exchanger is set as follows: When the heat source sides of multiple heat exchangers are arranged in a stepped manner side by side, the operating modes of the heat exchangers include: Independent heat exchange mode: The cold source sides of multiple heat exchangers are arranged in a stepped manner to achieve single heat extraction; Circulating heat exchange mode: The cold source sides of multiple heat exchangers are connected in an S-shape to achieve cascaded heat extraction from the cold source.

3. The design method for a zero-exhaust system of a geothermal station according to claim 1, characterized in that, The heat extraction strategy of the heat exchanger is set as follows: When the heat source sides of multiple heat exchangers are connected in an S-shape, the operating modes of the heat exchangers include: Independent heat exchange mode: The cold source sides of multiple heat exchangers are arranged in a stepped manner to realize the cascade utilization of heat source; Circulating heat exchange mode: The cold source sides of multiple heat exchangers are connected in an S-shape to achieve single heat extraction.

4. The design method for a zero-exhaust system of a geothermal station according to claim 1, characterized in that, The method for dynamically adjusting the extraction rate of geothermal wells based on real-time monitoring of the heat exchanger's operating conditions and the actual heating temperature at the heat load end using the temperature detection array, and based on a preset heating temperature range, is as follows: Based on the heat exchange efficiency of the heat exchanger under any heat extraction strategy, the utilization rate of geothermal well extraction volume per unit flow rate is calculated to generate a geothermal well extraction volume-heat exchange efficiency comparison table. A geothermal extraction dynamic adjustment model is constructed based on the geothermal well extraction volume-heat exchange efficiency comparison table. The geothermal extraction dynamic adjustment model uses the difference calculation method to calculate the deviation value ΔT between the second temperature information and the preset heating temperature range. When T 总 ≥T max When, ΔT=T 总 -T max ; When T 总 ≤T min When, ΔT=T 总 -T min ; Among them, T 总 For the second temperature information, the preset heating temperature range is [T]. min T max ]; When ΔT > 0, the heat supply is excessive. The geothermal extraction dynamic adjustment model reduces the current extraction volume of the geothermal well by several units based on the geothermal well extraction volume-heat exchange efficiency comparison table, so that ΔT approaches 0. When ΔT < 0, the heating supply is insufficient. The geothermal extraction dynamic adjustment model increases the current extraction volume of the geothermal well by several units based on the geothermal well extraction volume-heat exchange efficiency comparison table, so that ΔT approaches 0. When ΔT=0, the heat demand is met, and the geothermal extraction dynamic adjustment model maintains the current extraction volume of the geothermal well.

5. The design method for a zero-exhaust system of a geothermal station according to claim 4, characterized in that, The method for dynamically adjusting the heat exchanger's operating mode based on the real-time monitoring of the heat exchanger's operating conditions and the actual heating temperature at the heat load end using the temperature detection array, and based on a preset heating temperature range, is as follows: The geothermal extraction dynamic adjustment model calculates the temperature regulation parameter ΔT corresponding to the heat exchange pipes of each heat exchanger based on the deviation value ΔT between the second temperature information and the preset heating temperature range. i ; ΔT i =|ΔT|-T i ; Among them, T i This refers to the first temperature information of the heat exchange pipes built into the i-th heat exchanger and in operating condition. 1, 2, ..., n; If there exists at least one ΔT i If ΔT = 0, it is determined that the output temperature of part of the heat exchange pipes is adjusted. Specifically, when ΔT > 0, any set of ΔT is turned off. i =0 and is currently in the open state of the heat exchange pipe; when ΔT<0, then any set of ΔT is opened. i If the heat exchange pipe is ΔT = 0 and currently in a closed state, and all ΔT values ​​are detected at this time... i If all heat exchange pipes with a value of 0 are in the open state, then the opening degree of the proportional valve on the cold source input side of the heat exchanger is adjusted sequentially according to the heat source flow direction and the preset adjustment rule. The preset adjustment rule is set to reduce the opening degree of the proportional valve according to the preset unit quantity and adjustment frequency. If all ΔT i If the value is not equal to 0, then it is determined that the output temperature of all heat exchange pipes should be adjusted sequentially. In this case, T is selected first. i Closest to ΔT i The heat exchange pipes are regulated by calculating |T i -ΔT i The minimum value of | is determined; then, the filtered T is adjusted according to the sign of the current ΔT. i Closest to ΔT i The proportional valve opening degree of the heat exchanger in the heat exchange pipeline is determined by the following: when ΔT < 0, the proportional valve opening degree of the corresponding heat exchanger is reduced according to the preset adjustment rule until the proportional valve is fully closed; when ΔT > 0, the proportional valve opening degree of the heat exchanger is increased according to the preset adjustment rule until the proportional valve is fully open.

6. The design method for a zero-exhaust system of a geothermal station according to claim 5, characterized in that, When dynamically adjusting the operating mode of the heat exchanger, if, within a preset control cycle, ΔT is detected to still not approach 0 after any heat exchange pipe or heat exchanger has been continuously controlled several times, the control object is automatically switched to the next set of ΔT values. i The closest heat exchange pipe is used to avoid the accumulation of deviations caused by the failure of a single heat exchange pipe control.

7. The design method for a zero-exhaust system of a geothermal station according to claim 5, characterized in that, The opening degree of the proportional valve is preset to 5%-10% per cycle during the adjustment phase.

8. The design method for a zero-exhaust system of a geothermal station according to claim 1, characterized in that, The solid-liquid separator includes: The transfer station has a hollow internal structure, with water inlets and outlets on its outer perimeter and a slag discharge outlet at the bottom. A filter element is installed in the transfer station and forms an annular spiral filtration channel along its outer periphery to connect the inlet and outlet of the transfer station. The outlet of the transfer station extends into the filter element through a pipe that passes through the annular spiral filtration channel. The slag discharge unit has its feed end connected to the slag discharge port, and an electronic valve is installed at the slag discharge port. The electronic valve is configured to open for a corresponding time according to the discharge rate of the slag discharge port to discharge the impurities filtered by the filter element when the volume of impurities obtained by the geothermal fluid filtering within a preset detection cycle approaches the bottom of the filter element.

9. The design method for a zero-exhaust system of a geothermal station according to claim 1, characterized in that, The design method for the heat exchanger is set as follows: Detect the water composition and fluid temperature of geothermal wells; The distance between the geothermal well extraction end and the reinjection end is calculated according to the design drawings, and the optimal design position of the heat exchanger on the connecting pipeline between the geothermal well extraction end and the reinjection end is determined based on the density of the heat load user end. The optimal design position is configured such that the density of the heat load user end is greater than 70%-90%, thereby constructing the heat source transmission pipeline. The heat loss rate generated during heat source transportation is obtained based on the length of the heat source transportation pipeline and environmental influencing factors. The heat source input end temperature of the heat exchanger is calculated based on the heat loss rate and the fluid temperature of the geothermal well. Then, the total heat exchange efficiency of the heat exchanger is obtained based on the temperature difference between the heat source input end temperature of the heat exchanger and the heat load demand. The number, length, and flow area of ​​heat exchange pipes are designed based on the overall heat exchange efficiency of the heat exchanger. The material of the heat exchange pipe is selected based on the water quality composition and heat exchange efficiency of the geothermal well, and its corrosion resistance requirement is set to be greater than the preset service life.

10. The design method for a zero-exhaust system of a geothermal station according to claim 1, characterized in that, Based on the solid thermal bridge effect, multiple heat exchangers are integrated into a vacuum-insulated cavity. The vacuum level in the vacuum-insulated cavity must ensure that the heat loss of the heat exchangers is less than 40% under different operating conditions.

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