Molten salt mass calculation method, device and equipment of molten salt heat storage system and medium

Abstract

The invention discloses a fused salt mass calculation method, device and equipment of a fused salt heat storage system and a medium, and relates to the field of fused salt mass configuration. The total power consumption of fused salt heat storage is calculated by combining the load reduction rate of the coal-fired boiler and the unit load reduction rate requirement of the thermal generator set, and the total load reduction rate of fused salt is calculated according to the load reduction rate of the coal-fired boiler and the unit load reduction rate requirement; when the maximum load reduction rate of steam extraction heating is smaller than the total load reduction rate of the fused salt, multi-source heating is conducted through steam extraction heating and electric heater heating, and the heat storage demand quantity of the electric heater and the heat storage demand quantity of steam extraction heating are calculated; the total mass of the fused salt of the fused salt heat storage system is calculated based on the fused salt type, the fused salt temperature, the specific heat capacity of the fused salt, the heat storage demand quantity of the electric heater and the steam extraction heating heat storage demand quantity, the peak regulation requirement of the fused salt system can be met, cost is saved, and reliability and economical efficiency are both considered.

Description

Technical Field

[0001] This application relates to the field of molten salt mass configuration, and in particular to a method, apparatus, equipment and medium for calculating the molten salt mass of a molten salt thermal storage system. Background Technology

[0002] Against the backdrop of global energy structure transformation, national energy strategies are constantly being adjusted and optimized to achieve the safe, clean, and efficient use of energy. The basic approach and main measures are to deepen power system reform and build a green, low-carbon new power system with new energy sources as the mainstay. The large-scale grid connection of renewable energy sources, represented by wind and solar power, is accelerating the low-carbon transformation of the energy structure. At the same time, the intermittent, random, and volatile characteristics of new energy sources are making the contradiction of ensuring power balance increasingly prominent. The power system needs sufficient flexibility resources to ensure the safe operation of the power grid.

[0003] Energy storage technology, as a key technology for balancing grid supply and demand, improving energy efficiency, and enhancing the grid connection capabilities of renewable energy sources, has received widespread attention. Compared with other energy storage technologies, molten salt energy storage technology features high safety, long lifespan, small footprint, and low cost per unit capacity. Molten salt coupled thermal power units can achieve thermoelectric decoupling, offering unique advantages in improving the deep peak-shaving capacity of existing coal-fired power units. Integrating electric heaters and extraction steam storage into molten salt thermal storage systems can further improve their performance; however, current research on optimal molten salt quality configuration for such systems is limited, and there are no established standards for reference.

[0004] Therefore, for the optimization configuration scheme of molten salt quality in such multi-heat source systems, there is an urgent need for a molten salt quality calculation method that can balance reliability and economy. Summary of the Invention

[0005] The purpose of this application is to provide a method, apparatus, equipment and medium for calculating the molten salt mass of a molten salt thermal storage system, which can meet the peak-shaving needs of the molten salt system and save costs as much as possible, while taking into account reliability and economy, and realize the molten salt mass configuration of the integrated multi-heat source molten salt thermal storage system.

[0006] To achieve the above objectives, this application provides the following solution: In a first aspect, this application provides a method for calculating the molten salt mass of a molten salt thermal storage system, including: Determine the maximum peak-shaving demand for load reduction in the molten salt thermal storage system; the molten salt thermal storage system is a molten salt thermal storage system coupled with thermal power units. Based on the maximum peak load reduction demand of the molten salt thermal storage system, the load reduction rate of the coal-fired boiler, and the unit load reduction rate demand of the thermal power generating unit, calculate the total power consumption of the molten salt thermal storage system, and calculate the total load reduction rate of the molten salt system based on the load reduction rate of the coal-fired boiler and the unit load reduction rate demand of the thermal power generating unit. Determine whether the maximum load reduction rate of extraction steam heating is less than the total load reduction rate of molten salt. If so, multi-source heating is carried out through extraction steam heating and electric heater heating. Calculate the heat storage demand of electric heater and the heat storage demand of extraction steam heating based on the ratio of the total power consumption of molten salt heat storage to the power consumption of molten salt heat storage through extraction steam heating and electric heater heating. The total mass of molten salt in the molten salt thermal storage system is calculated based on the type of molten salt, molten salt temperature, specific heat capacity of molten salt, heat storage requirements of electric heaters, and heat storage requirements of extraction steam heating.

[0007] Optionally, determine the maximum peak-shaving demand for load reduction in the molten salt thermal storage system, specifically including: Obtain the load reduction command sequence within a preset time period from the DCS system of the thermal power unit, where the load reduction command is the load reduction command below 50% of the rated load of the thermal power unit; The load reduction command data is processed, bad values ​​are removed, and the 90th percentile is estimated using a nonparametric method. The value corresponding to the 90th percentile is taken as the maximum peak-shaving demand for load reduction in the molten salt thermal storage system.

[0008] Optionally, the formula for calculating the total power consumption of molten salt thermal storage is as follows: ; in, This represents the total power consumption for molten salt thermal storage. To reduce the maximum peak load demand of the molten salt thermal storage system; For coal-fired boilers, the rate of load reduction; To meet the load reduction rate requirements of the generating units.

[0009] Optionally, the total molten salt load reduction rate is calculated based on the load reduction rate of the coal-fired boiler and the unit load reduction rate requirement of the thermal power generating unit. Specifically, this includes subtracting the load reduction rate of the coal-fired boiler from the unit load reduction rate requirement of the thermal power generating unit to obtain the total molten salt load reduction rate.

[0010] Optionally, the calculation formulas for the heat storage requirements of the electric heater and the heat storage requirements of the extraction steam heating are as follows: ; ; ; in, This refers to the heat storage requirements of electric heaters. This is the demand for steam extraction heating and heat storage. The ratio of the power consumption for molten salt thermal storage to that for both steam extraction heating and electric heater heating. This represents the total power consumption for molten salt thermal storage. For the heat storage efficiency of electric heaters; To improve the efficiency of steam extraction heating and heat storage; This represents the maximum load reduction rate for steam extraction heating. This represents the total rate of load reduction for molten salt.

[0011] Optionally, the method for calculating the molten salt mass of the molten salt thermal storage system further includes: when the maximum load reduction rate of steam extraction heating is not less than the total load reduction rate of molten salt, calculating the total mass of molten salt based on the type of molten salt, the temperature of molten salt, the specific heat capacity of molten salt, and the demand for steam extraction heating and thermal storage.

[0012] Optionally, the total mass of molten salt in the molten salt thermal storage system is calculated based on the type of molten salt, molten salt temperature, specific heat capacity of the molten salt, the heat storage demand of the electric heater, and the heat storage demand of the extraction steam heating system. Specifically, this includes: The melting point and decomposition point of the molten salt are determined according to the type of molten salt. The temperature of the molten salt in the low-temperature molten salt tank is calculated based on the melting point and anti-solidification margin of the molten salt. The temperature of the molten salt in the high-temperature molten salt tank is calculated based on the decomposition point and decomposition margin of the molten salt. The molten salt temperature in the low-temperature molten salt tank and the molten salt temperature in the high-temperature molten salt tank are used as the lower and upper limits of the molten salt temperature when calculating the specific heat capacity integral of the molten salt, respectively. The mass of molten salt required for electric heating is calculated based on the heat storage demand of the electric heater. The molten salt temperature in the low-temperature molten salt tank and the molten salt temperature in the high-temperature molten salt tank are used as the lower limit and upper limit of the molten salt temperature when calculating the specific heat capacity integral of the molten salt, respectively. The mass of molten salt required for steam extraction heating is calculated based on the demand for steam extraction heating and heat storage. The total mass of molten salt in the molten salt thermal storage system is calculated based on the mass of molten salt required for electric heating, the mass of molten salt required for steam extraction heating, and the flow rate of non-flowing molten salt.

[0013] Secondly, this application provides a molten salt mass calculation device for a molten salt thermal storage system, comprising: The module for determining the maximum load reduction and peak shaving demand of the molten salt thermal storage system is used to determine the maximum load reduction and peak shaving demand of the molten salt thermal storage system; the molten salt thermal storage system is a molten salt thermal storage system coupled with a thermal power unit. The power consumption and total load reduction rate calculation module is used to calculate the total power consumption of molten salt thermal storage based on the maximum peak load reduction demand of the molten salt thermal storage system, the load reduction rate of the coal-fired boiler, and the unit load reduction rate demand of the thermal power generating unit, and to calculate the total load reduction rate of molten salt based on the load reduction rate of the coal-fired boiler and the unit load reduction rate demand of the thermal power generating unit. The heat storage demand calculation module is used to determine whether the maximum load reduction rate of steam extraction heating is less than the total load reduction rate of molten salt. If so, multi-source heating is carried out through steam extraction heating and electric heater heating. The heat storage demand of electric heater and the heat storage demand of steam extraction heating are calculated based on the ratio of the total power consumption of molten salt heat storage to the power consumption of molten salt heat storage through steam extraction heating and electric heater heating. The molten salt total mass calculation module is used to calculate the total mass of molten salt in a molten salt thermal storage system based on the type of molten salt, molten salt temperature, specific heat capacity of molten salt, heat storage demand of electric heater, and heat storage demand of extraction steam heating.

[0014] Thirdly, this application provides a computer device, including: a memory, a processor, and a computer program stored in the memory and capable of running on the processor, wherein the processor executes the computer program to implement the above-described method for calculating the molten salt mass of the molten salt thermal storage system.

[0015] Fourthly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-described method for calculating the molten salt mass of the molten salt thermal storage system.

[0016] According to the specific embodiments provided in this application, the following technical effects are disclosed: This application provides a method, apparatus, equipment, and medium for calculating the molten salt mass of a molten salt thermal storage system. First, the maximum peak-shaving demand for load reduction in the molten salt thermal storage system is determined. Based on this demand, the load reduction rate of the coal-fired boiler, and the unit load reduction rate of the thermal power generating unit, the total power consumption of the molten salt thermal storage is calculated. Then, based on the load reduction rate of the coal-fired boiler and the unit load reduction rate of the thermal power generating unit, the total load reduction rate of the molten salt is calculated. It is then determined whether the maximum load reduction rate of the extraction steam heating is less than the total load reduction rate of the molten salt. When the extraction steam heating is subject to safety limitations... When the required load reduction rate of the molten salt system cannot be met (i.e., the maximum load reduction rate of extraction steam heating is less than the total load reduction rate of the molten salt), the deficiency is compensated by electric heaters. Multi-source heating is achieved through extraction steam heating and electric heater heating. The heat storage requirements of electric heaters and extraction steam heating are calculated based on the ratio of the total power consumption of molten salt heat storage to the power consumption of extraction steam heating and electric heater heating. The total mass of molten salt in the molten salt heat storage system is calculated based on the type, temperature, and specific heat capacity of the molten salt, as well as the heat storage requirements of electric heaters and extraction steam heating. This application can meet the peak-shaving needs of the molten salt system while minimizing costs, balancing reliability and economy, and realizing the molten salt mass configuration of an integrated multi-heat-source molten salt heat storage system. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is an application environment diagram of a molten salt mass calculation method for a molten salt thermal storage system according to an embodiment of this application.

[0019] Figure 2 This is a flowchart illustrating a method for calculating the molten salt mass of a molten salt thermal storage system, provided as an embodiment of this application.

[0020] Figure 3 This is a schematic diagram illustrating the specific process of a method for calculating the molten salt mass of a molten salt thermal storage system provided in an embodiment of this application.

[0021] Figure 4 This is a schematic diagram of the unit output curve provided in an embodiment of this application.

[0022] Figure 5 This is a schematic diagram of unit power variation provided in an embodiment of this application.

[0023] Figure 6 This is a schematic diagram showing the change of a molten salt thermal storage system over time, as provided in an embodiment of this application.

[0024] Figure 7 This is a schematic diagram illustrating the power variation of a molten salt system using a multi-source heating method, as provided in an embodiment of this application.

[0025] Figure 8 This is a schematic diagram of the functional modules of a molten salt mass calculation device for a molten salt thermal storage system provided in an embodiment of this application.

[0026] Figure 9 This is a schematic diagram of the structure of a computer device provided in an embodiment of this application. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] The molten salt mass calculation method for molten salt thermal storage systems provided in this application embodiment can be applied to, for example... Figure 1 In the application environment shown, terminal 102 communicates with server 104 via a network. A data storage system can store the data that server 104 needs to process. The data storage system can be set up independently, integrated into server 104, or placed in the cloud or on another server. Terminal 102 can send pending requests to server 104. After receiving the pending requests, server 104 determines the maximum peak-shaving demand for load reduction in the molten salt thermal storage system. Based on the maximum peak-shaving demand for load reduction in the molten salt thermal storage system, the load reduction rate of the coal-fired boiler, and the unit load reduction rate demand of the thermal power generating unit, server 104 calculates the total power consumption of molten salt thermal storage. Based on the load reduction rate of the coal-fired boiler and the unit load reduction rate demand of the thermal power generating unit, server 104 calculates the total load reduction rate of molten salt thermal storage. Server 104 determines whether the maximum load reduction rate of extraction steam heating is less than the total load reduction rate of molten salt thermal storage. If so, server 104 performs multi-source heating through extraction steam heating and electric heater heating. Based on the total power consumption of molten salt thermal storage and the ratio of the power consumption of extraction steam heating and electric heater heating, server 104 calculates the heat storage demand of electric heater heating and extraction steam heating. Based on the type of molten salt, molten salt temperature, specific heat capacity of molten salt, heat storage demand of electric heater heating and heat storage demand of extraction steam heating, server 104 calculates the total mass of molten salt in the molten salt thermal storage system. Server 104 can feed back the total mass of molten salt obtained in response to the request to terminal 102. Furthermore, in some embodiments, the method for calculating the mass of molten salt in the molten salt thermal storage system can also be implemented separately by server 104 or terminal 102. For example, terminal 102 can directly calculate the mass of molten salt for the request to be processed, or server 104 can obtain the request to be processed from the data storage system and calculate the mass of molten salt for the request.

[0030] The terminal 102 can be, but is not limited to, various desktop computers and laptops. The server 104 can be implemented using a standalone server or a server cluster consisting of multiple servers, or it can be a cloud server.

[0031] In one exemplary embodiment, such as Figure 2 As shown, a method for calculating the molten salt mass in a molten salt thermal storage system is provided. This method is executed by a computer device, specifically by a terminal or server alone, or by both a terminal and a server. In this embodiment, the method is applied to... Figure 1 Taking server 104 as an example, the explanation includes the following steps 201 to 204.

[0032] Step 201: Determine the maximum peak-shaving demand for load reduction of the molten salt thermal storage system; the molten salt thermal storage system is a molten salt thermal storage system coupled with a thermal power unit.

[0033] Step 202: Calculate the total power consumption of molten salt thermal storage based on the maximum peak load reduction demand of the molten salt thermal storage system, the load reduction rate of the coal-fired boiler, and the unit load reduction rate demand of the thermal power generating unit. Calculate the total load reduction rate of the molten salt thermal storage system based on the load reduction rate of the coal-fired boiler and the unit load reduction rate demand of the thermal power generating unit.

[0034] Step 203: Determine whether the maximum load reduction rate of steam extraction heating is less than the total load reduction rate of molten salt. If so, multi-source heating is carried out through steam extraction heating and electric heater heating. Calculate the heat storage demand of electric heater and the heat storage demand of steam extraction heating based on the ratio of the total power consumption of molten salt heat storage to the power consumption of molten salt heat storage through steam extraction heating and electric heater heating.

[0035] Step 204: Calculate the total mass of molten salt in the molten salt thermal storage system based on the type of molten salt, molten salt temperature, specific heat capacity of molten salt, heat storage demand of electric heater, and heat storage demand of extraction steam heating.

[0036] Implementing steps 201 to 204 above provides guidance for the calculation scheme of molten salt quality configuration in integrated multi-heat-source molten salt thermal storage systems. First, the power demand of the molten salt thermal storage system during continuous peak shaving is determined based on statistical analysis. Then, based on the deviation between the unit's required load reduction rate and the fastest achievable load reduction rate of the coal-fired unit, the unit's required load reduction rate for the molten salt system is calculated. For multi-heat-source thermal storage systems coupled with electric heaters and extraction steam heating, the electric heaters have a rapid response. When extraction steam heating is limited by safety constraints and cannot meet the required load reduction rate of the molten salt system, the electric heaters compensate for the deficiency. The purpose of this method is to meet the peak shaving needs of the molten salt system while minimizing costs, balancing reliability and economy, optimizing energy utilization, and providing a methodology for the molten salt quality design of integrated multi-heat-source molten salt thermal storage systems.

[0037] With the increasing research on molten salt thermal storage-assisted coal-fired power units, various molten salt coupling systems have been proposed. However, there is relatively little focus on the molten salt capacity configuration under each coupling system. Molten salt systems have a dual function of heat storage and release. During heat storage, molten salt flows from the cold tank to the hot tank. During heat release, molten salt flows from the hot tank to the cold tank. After the grid connection of new energy sources, the low-load operating time of coal-fired power units has increased significantly, making the demand for molten salt peak shaving increasingly urgent.

[0038] Against this backdrop, molten salt thermal energy storage has become a primary means of rapidly reducing the load on auxiliary units. Furthermore, the maximum heat release capacity of the molten salt system depends on the thermal energy storage; therefore, this application performs calculations on the configuration of molten salt mass to meet the load reduction requirements of molten salt thermal energy storage.

[0039] The two most commonly used schemes for molten salt thermal storage systems coupled with thermal power units are steam extraction heating and electric heater heating.

[0040] The heat storage strategy for extraction steam heating is as follows: a portion of the main steam is diverted and enters the molten salt heat exchanger for heat exchange, heating the low-temperature molten salt flowing into the heat exchanger into high-temperature molten salt, so that the high-temperature molten salt carries heat into the high-temperature salt tank for heat storage, and the low-temperature steam is discharged into the condenser through desuperheating and depressurization.

[0041] The electric heater is connected to the plant's auxiliary power bus via a power regulator (PCS) and a transformer. By changing the electric load of the electric heater, the grid power of the unit is indirectly adjusted, thereby achieving the purpose of assisting the coal-fired unit in rapid regulation. The electric heater has a response time on the order of seconds, enabling rapid peak shaving.

[0042] like Figure 3 As shown, the maximum load reduction and peak-shaving demand of the molten salt thermal energy storage system is first obtained based on statistical analysis. In a specific example, step 201 above, determining the maximum load reduction and peak-shaving demand of the molten salt thermal energy storage system, specifically includes: obtaining a sequence of load reduction instructions within a preset time period from the DCS (Distributed Control System) of the thermal power unit, wherein the load reduction instructions are those below 50% of the rated load of the thermal power unit; processing the load reduction instruction data, removing outliers, estimating the 90th quantile using a nonparametric method, and taking the value corresponding to the 90th quantile as the maximum load reduction and peak-shaving demand of the molten salt thermal energy storage system.

[0043] Deep peak shaving is closely related to instructions issued by power dispatching and trading institutions. Generating units adjust their active power in real time according to a certain regulation rate to meet the requirements of power system frequency and tie-line power control. When generating unit power changes, the molten salt system comes into play to perform deep peak shaving.

[0044] Studies have shown that when the unit load drops to 50% THA, both the coal consumption rate and heat consumption rate for power generation increase sharply. When the unit operating load is above 50%, peak shaving can be achieved by relying on the regulating capacity of the coal-fired power unit itself; when the unit operating load is below 50%, relying on the unit itself for peak shaving will lead to an increase in the coal consumption rate and heat consumption rate for power generation, thereby reducing the economic efficiency of the unit operation.

[0045] Assume the deviation of the AGC load reduction command for the unit below 50% rated load is: ,like Figure 4 As shown, the AGC command is a power command issued by the power grid to the thermal power unit, which can be obtained from the DCS of the thermal power unit.

[0046] We retrieved one week's worth of AGC (Automatic Gauge Control) command data from the DCS (Distributed Control System) of the thermal power unit. Among these, there were n load reduction commands below 50% of the rated load, resulting in the following load reduction command sequence: After performing simple data processing to remove obviously bad values, the 90th quantile was estimated using a nonparametric method. (Sort the observed data samples from smallest to largest and find the value at the 90th percentile). The 90th percentile indicates that the obtained value has a 90% probability of exceeding the daily load reduction and peak-shaving demand of the molten salt thermal storage system. When the molten salt peak-shaving capacity is greater than or equal to... This is sufficient for most everyday situations. Definition To reduce the maximum peak load demand of the molten salt thermal storage system (i.e. Figure 3 Molten salt thermal storage demand ).

[0047] The above measures can mitigate the impact of some unforeseen circumstances, making the conclusions universally applicable.

[0048] The following is a power analysis of the molten salt thermal storage process: To address the grid integration issues of renewable energy generation, the power grid has placed higher demands on the load shifting rate of thermal power generating units. The power grid typically considers the unit's load shifting rate a crucial performance indicator. The grid requires that the unit possess [specific performance characteristics] during low-load periods. When the load reduction rate is set at Pe / min, coal-fired boilers should reduce their load at the same rate. However, the load reduction rate of coal-fired boilers is constrained and cannot meet the unit's load reduction rate requirements on its own. Constraining factors include: rapid changes in the temperature and pressure parameters of the working fluid during rapid load changes lead to significant thermal stress on thick-walled components, affecting equipment lifespan; boiler design focuses more on high-load conditions and less on low-load conditions, thus limiting the unit's load reduction capacity due to its own parameters.

[0049] As can be seen from the above, a coal-fired boiler alone cannot meet the requirements and therefore needs to be coupled with a molten salt system. Let's assume the maximum load reduction rate of the coal-fired boiler is limited to only... Pe / min, where < Throughout the process, the unit power changed as follows: Figure 5 As shown.

[0050] To meet the unit's load reduction rate requirements, a molten salt system is needed to cooperate with the coal-fired boiler in reducing the load. This can be seen from the physical meaning of the horizontal and vertical axes. Figure 5 The yellow area (i.e., the area of ​​triangle ACD) represents the total power consumption of molten salt thermal energy storage under the condition of meeting the grid load reduction rate requirement, denoted as... .

[0051] The formula for calculating the total power consumption of molten salt thermal storage is as follows: (1); in, This represents the total power consumption for molten salt thermal storage. To reduce the maximum peak load demand of the molten salt thermal storage system; For coal-fired boilers, the rate of load reduction; The rate of load reduction required for the unit (also known as...) Figure 3 The required rate of load reduction for the generating units (in the middle). To reduce the load rate of coal-fired boilers To achieve the maximum peak-shaving demand for load reduction in molten salt thermal storage systems Time to reduce power ; To meet the demand for unit load reduction rate To achieve the maximum peak-shaving demand for load reduction in molten salt thermal storage systems Time to reduce power .

[0052] The molten salt de-loading rate needs to be greater than or equal to the total molten salt de-loading rate. Pe / min: (2); in, For coal-fired boilers, the rate of load reduction; To meet the unit's load reduction rate requirements; In step 202, the total load reduction rate of molten salt is calculated based on the load reduction rate of the coal-fired boiler and the unit load reduction rate requirement of the thermal power generating unit. Specifically, this includes: calculating the load reduction rate of the coal-fired boiler... The load reduction rate requirement of thermal power generating units The total load reduction rate of the molten salt is obtained by subtraction.

[0053] Molten salt thermal storage system with molten salt total load reduction rate The Pe / min rate rises to its peak value, then gradually decreases and the load is withdrawn, assisting the coal-fired unit in peak shaving, such as Figure 6 As shown.

[0054] The following is a calculation of the molten salt heat storage demand: For safety reasons, when using a single steam source for heating, to avoid safety accidents caused by reheater overheating, the extracted main steam cannot exceed 20%. When using extraction steam heating, there is an upper limit to the molten salt load reduction rate, which is obtained from the safety limits of extraction steam heating. Let this upper limit be the maximum load reduction rate of extraction steam heating. Pe / min.

[0055] Extraction steam heating of molten salt has high heat storage efficiency, making it the preferred method. However, there is an upper limit to the load reduction rate of extraction steam heating. If extraction steam heating cannot achieve the required load reduction rate, i.e. Less than the total load reduction rate of molten salt This requirement can be met by an electric heater. The power variation of the molten salt system is as follows: Figure 7 As shown.

[0056] According to the physical meaning of the horizontal and vertical axes, Figure 7 The yellow area (area of ​​quadrilateral OEFG) represents the power consumption of the electric heater for molten salt heat storage, and the white area (area of ​​triangle OFG) represents the power consumption of the extraction steam heater for molten salt heat storage. The ratio of the power consumption of the electric heater to that of the extraction steam heater for molten salt heat storage is... That is, the ratio of the areas of quadrilateral OEFG and triangle OFG (i.e., Figure 3 The proportion of electric heaters and extraction steam heating in the system can be calculated as follows: (3).

[0057] The total power consumption for molten salt thermal storage calculated from the previous step is: Let the heat storage demand during the electric heater and steam extraction heating heat storage process be respectively... and The calculation formulas for the heat storage requirements of electric heaters and the heat storage requirements of extraction steam heating are as follows: (4); (5); in, This refers to the heat storage requirements of electric heaters. This is the demand for steam extraction heating and heat storage. The ratio of the power consumption for molten salt thermal storage to that for both steam extraction heating and electric heater heating. This represents the total power consumption for molten salt thermal storage. The heat storage efficiency of the electric heater is expressed in % (%). The efficiency of steam extraction heating and thermal storage is expressed in percentage.

[0058] The following is the calculation of the molten salt mass: In step 204 above, the total mass of molten salt in the molten salt thermal storage system is calculated based on the type of molten salt, the temperature of molten salt, the specific heat capacity of molten salt, the heat storage demand of electric heater and the heat storage demand of extraction steam heating. Specifically, this includes the following steps 301 to 304.

[0059] Step 301: Determine the melting point and decomposition point of the molten salt according to the type of molten salt, and calculate the temperature of the molten salt in the low-temperature molten salt tank according to the melting point and anti-solidification margin of the molten salt, and calculate the temperature of the molten salt in the high-temperature molten salt tank according to the decomposition point and decomposition margin of the molten salt.

[0060] First, the type of molten salt is selected. Since Hitec salt (53% KNO3, 40% NaNO2 and 7% NaNO3, i.e., a ternary salt) is widely used in medium-temperature industrial heating, its operating temperature range matches the steam parameters of coal-fired units well, and it has good performance, the following calculations will be performed using this molten salt as an example.

[0061] Hitz salts have a relatively low melting point of approximately 142°C, although some researchers believe the maximum operating temperature can reach 450°C. In engineering applications, the minimum operating temperature of molten salts is generally higher than their melting point to ensure complete melting. The melting point of molten salts should be considered. and decomposition point (Determined by the properties of molten salt), the temperature of the molten salt in the cryogenic molten salt vessel can be obtained. and high-temperature molten salt tank The molten salt temperatures in the samples are as follows: (6); (7); in, The anti-freezing margin considered to ensure low viscosity operation of molten salt is expressed in °C, and is generally selected as above 50°C. The decomposition margin considered to ensure the safe and stable operation of molten salt is expressed in °C, and is generally selected as 10-50°C.

[0062] Step 302: Using the molten salt temperature in the low-temperature molten salt tank and the molten salt temperature in the high-temperature molten salt tank as the lower and upper limits of the molten salt temperature when calculating the specific heat capacity integral of the molten salt, respectively, calculate the mass of molten salt required for electric heating based on the heat storage demand of the electric heater.

[0063] The specific heat capacity C of molten salt is a fundamental physical property parameter that varies with the molten salt temperature and is a function of the molten salt temperature. Let the amounts of cold molten salt required for electric heating and steam extraction heating be respectively... and The unit is 3.6 × 10 6 kg; The temperature is the molten salt temperature, expressed in °C.

[0064] (8).

[0065] in, The temperature of the molten salt; It is a function that varies with the temperature of the molten salt.

[0066] The formula for calculating the mass of molten salt required for electric heating is as follows: (9).

[0067] Step 303: Using the molten salt temperatures in the low-temperature molten salt tank and the high-temperature molten salt tank as the lower and upper limits of the molten salt temperature for calculating the specific heat capacity integral, respectively, calculate the required mass of molten salt for steam extraction heating and heat storage based on the demand for steam extraction heating and heat storage. The formula for calculating the required mass of molten salt for the steam extraction and heat storage system is as follows: (10).

[0068] Step 304: Calculate the total mass of molten salt in the molten salt thermal storage system based on the required molten salt mass for electric heating, the required molten salt mass for steam extraction heating, and the flow rate of the non-flowable molten salt. Based on the calculations of the required molten salt mass for electric heating and steam extraction heating, and considering a 15% non-flowable molten salt flow rate, the formula for calculating the total mass m of the molten salt thermal storage system integrating electric heating and steam extraction thermal storage is as follows: (11).

[0069] The method for calculating the molten salt mass of the molten salt thermal storage system further includes: when the maximum load reduction rate of steam extraction heating is not less than the total load reduction rate of molten salt, the total mass of molten salt is calculated based on the type of molten salt, the temperature of molten salt, the specific heat capacity of molten salt, and the demand for steam extraction heating and thermal storage. That is, when the maximum load reduction rate of steam extraction heating is not less than the total load reduction rate of molten salt, only steam extraction thermal storage is used for heating. At this time, the required molten salt mass of the steam extraction thermal storage system is calculated according to formula (10), and the required molten salt mass of the steam extraction thermal storage system is taken as the total molten salt mass of the molten salt thermal storage system.

[0070] Currently, the two most commonly used schemes for molten salt thermal storage systems coupled with thermal power units are extraction steam heating and electric heater heating. Extraction steam heating has higher efficiency, while electric heater heating has a faster response. For multi-source thermal storage systems coupled with electric heaters and extraction steam heating, when extraction steam heating cannot meet the load reduction rate requirements of the molten salt system due to safety limitations, the electric heater can compensate for the deficiency. This application provides a new method for calculating molten salt mass, which meets the peak-shaving needs of molten salt systems while minimizing costs, balancing reliability and economy, and provides a methodology for configuring molten salt mass in integrated multi-source molten salt thermal storage systems.

[0071] This application also provides an application scenario in which the above-described method for calculating the molten salt mass of a molten salt thermal storage system is applied. Specifically, the molten salt mass calculation method for a molten salt thermal storage system provided in this embodiment can be applied in a content distribution scenario. The molten salt mass calculation scenario includes a request generation stage and a molten salt mass calculation stage; the request to be processed enters the molten salt mass calculation stage from the request generation stage, and the total molten salt mass is obtained through human-machine collaboration. The molten salt mass calculation method for a molten salt thermal storage system provided in this embodiment belongs to the molten salt mass calculation stage. Specifically, in the process of calculating the molten salt mass in response to the request, the maximum peak-shaving demand for load reduction of the molten salt thermal storage system can be determined. Based on the maximum peak-shaving demand for load reduction of the molten salt thermal storage system, the load reduction rate of the coal-fired boiler, and the unit load reduction rate demand of the thermal power generating unit, the total power consumption of molten salt thermal storage is calculated. The total load reduction rate of molten salt is calculated based on the load reduction rate of the coal-fired boiler and the unit load reduction rate demand of the thermal power generating unit. It is then determined whether the maximum load reduction rate of extraction steam heating is less than the total load reduction rate of molten salt. If so, multi-source heating is carried out through extraction steam heating and electric heater heating. The heat storage demand of electric heater and extraction steam heating is calculated based on the ratio of the total power consumption of molten salt thermal storage to the power consumption of molten salt thermal storage through extraction steam heating and electric heater heating. Based on the type of molten salt, the temperature of molten salt, the specific heat capacity of molten salt, the heat storage demand of electric heater and the heat storage demand of extraction steam heating, the total mass of molten salt in the molten salt thermal storage system is calculated.

[0072] Based on the same inventive concept, this application also provides a molten salt mass calculation device for implementing the molten salt mass calculation method for the molten salt thermal storage system described above. The solution provided by this device is similar to the solution described in the above method. Therefore, the specific limitations of one or more embodiments of the molten salt mass calculation device for the molten salt thermal storage system provided below can be found in the limitations of the molten salt mass calculation method for the molten salt thermal storage system described above, and will not be repeated here.

[0073] In one exemplary embodiment, such as Figure 8 As shown, a molten salt mass calculation device for a molten salt thermal storage system is provided, comprising the following modules.

[0074] The module T1 for determining the maximum peak-shaving demand for load reduction in the molten salt thermal storage system is used to determine the maximum peak-shaving demand for load reduction in the molten salt thermal storage system; the molten salt thermal storage system is a molten salt thermal storage system coupled with a thermal power unit.

[0075] The power consumption and total load reduction rate calculation module T2 is used to calculate the total power consumption of molten salt thermal storage based on the maximum peak load reduction demand of the molten salt thermal storage system, the load reduction rate of the coal-fired boiler, and the unit load reduction rate demand of the thermal power generating unit, and to calculate the total load reduction rate of molten salt based on the load reduction rate of the coal-fired boiler and the unit load reduction rate demand of the thermal power generating unit.

[0076] The heat storage demand calculation module T3 is used to determine whether the maximum load reduction rate of steam extraction heating is less than the total load reduction rate of molten salt. If so, multi-source heating is carried out through steam extraction heating and electric heater heating. The heat storage demand of electric heater and the heat storage demand of steam extraction heating are calculated based on the ratio of the total power consumption of molten salt heat storage to the power consumption of molten salt heat storage through steam extraction heating and electric heater heating.

[0077] The molten salt total mass calculation module T4 is used to calculate the total mass of molten salt in the molten salt thermal storage system based on the type of molten salt, molten salt temperature, specific heat capacity of molten salt, heat storage demand of electric heater, and heat storage demand of extraction steam heating.

[0078] In one exemplary embodiment, a computer device is provided, which may be a server or a terminal, and its internal structure diagram may be as follows. Figure 9 As shown, the computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The database stores molten salt mass calculation data. The I / O interfaces are used for exchanging information between the processor and external devices. The communication interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements a method for calculating the molten salt mass of a molten salt thermal storage system.

[0079] Those skilled in the art will understand that Figure 9 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0080] In one exemplary embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method embodiments.

[0081] In one exemplary embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0082] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0083] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0084] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0085] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0086] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for calculating the mass of molten salt in a molten salt thermal storage system, characterized in that, The method for calculating the molten salt mass of the molten salt thermal storage system includes: Determine the maximum peak-shaving demand for load reduction in the molten salt thermal storage system; the molten salt thermal storage system is a molten salt thermal storage system coupled with thermal power units. Based on the maximum peak load reduction demand of the molten salt thermal storage system, the load reduction rate of the coal-fired boiler, and the unit load reduction rate demand of the thermal power generating unit, calculate the total power consumption of the molten salt thermal storage system, and calculate the total load reduction rate of the molten salt system based on the load reduction rate of the coal-fired boiler and the unit load reduction rate demand of the thermal power generating unit. Determine whether the maximum load reduction rate of extraction steam heating is less than the total load reduction rate of molten salt. If so, multi-source heating is carried out through extraction steam heating and electric heater heating. Calculate the heat storage demand of electric heater and the heat storage demand of extraction steam heating based on the ratio of the total power consumption of molten salt heat storage to the power consumption of molten salt heat storage through extraction steam heating and electric heater heating. The total mass of molten salt in the molten salt thermal storage system is calculated based on the type of molten salt, molten salt temperature, specific heat capacity of molten salt, heat storage requirements of electric heaters, and heat storage requirements of extraction steam heating.

2. The method for calculating the molten salt mass of the molten salt thermal storage system according to claim 1, characterized in that, Determine the maximum peak-shaving demand for load reduction in molten salt thermal storage systems, specifically including: Obtain the load reduction command sequence within a preset time period from the DCS system of the thermal power unit, where the load reduction command is the load reduction command below 50% of the rated load of the thermal power unit; The load reduction command data is processed, bad values ​​are removed, and the 90th percentile is estimated using a nonparametric method. The value corresponding to the 90th percentile is taken as the maximum peak-shaving demand for load reduction in the molten salt thermal storage system.

3. The method for calculating the molten salt mass of the molten salt thermal storage system according to claim 1, characterized in that, The formula for calculating the total power consumption of molten salt thermal storage is as follows: ； in, This represents the total power consumption for molten salt thermal storage. To reduce the maximum peak load demand of the molten salt thermal storage system; For coal-fired boilers, the rate of load reduction; To meet the load reduction rate requirements of the generating units.

4. The method for calculating the molten salt mass of the molten salt thermal storage system according to claim 1, characterized in that, The total molten salt load reduction rate is calculated based on the load reduction rate of coal-fired boilers and the load reduction rate requirements of thermal power generating units. Specifically, this involves subtracting the load reduction rate of coal-fired boilers from the load reduction rate requirements of thermal power generating units to obtain the total molten salt load reduction rate.

5. The method for calculating the molten salt mass of the molten salt thermal storage system according to claim 1, characterized in that, The formulas for calculating the heat storage requirements of electric heaters and the heat storage requirements of extraction steam heating are as follows: ； ； ； in, The heat storage requirement for electric heaters; This is the demand for steam extraction heating and heat storage. The ratio of the power consumption for molten salt thermal storage to that for both steam extraction heating and electric heater heating. This represents the total power consumption for molten salt thermal storage. For the heat storage efficiency of electric heaters; To improve the efficiency of steam extraction heating and heat storage; This represents the maximum load reduction rate for steam extraction heating. This represents the total rate of load reduction for molten salt.

6. The method for calculating the molten salt mass of the molten salt thermal storage system according to claim 1, characterized in that, The method for calculating the molten salt mass of the molten salt thermal storage system further includes: when the maximum load reduction rate of steam extraction heating is not less than the total load reduction rate of molten salt, the total mass of molten salt is calculated based on the type of molten salt, the temperature of molten salt, the specific heat capacity of molten salt, and the demand for steam extraction heating and thermal storage.

7. The method for calculating the molten salt mass of the molten salt thermal storage system according to claim 1, characterized in that, The total mass of molten salt in the molten salt thermal storage system is calculated based on the type of molten salt, molten salt temperature, specific heat capacity of molten salt, heat storage requirements of electric heaters and heat storage requirements of extraction steam heating, specifically including: The melting point and decomposition point of the molten salt are determined according to the type of molten salt. The temperature of the molten salt in the low-temperature molten salt tank is calculated based on the melting point and anti-solidification margin of the molten salt. The temperature of the molten salt in the high-temperature molten salt tank is calculated based on the decomposition point and decomposition margin of the molten salt. The molten salt temperature in the low-temperature molten salt tank and the molten salt temperature in the high-temperature molten salt tank are used as the lower and upper limits of the molten salt temperature when calculating the specific heat capacity integral of the molten salt, respectively. The mass of molten salt required for electric heating is calculated based on the heat storage demand of the electric heater. The molten salt temperature in the low-temperature molten salt tank and the molten salt temperature in the high-temperature molten salt tank are used as the lower limit and upper limit of the molten salt temperature when calculating the specific heat capacity integral of the molten salt, respectively. The mass of molten salt required for steam extraction heating is calculated based on the demand for steam extraction heating and heat storage. The total mass of molten salt in the molten salt thermal storage system is calculated based on the mass of molten salt required for electric heating, the mass of molten salt required for steam extraction heating, and the flow rate of non-flowing molten salt.

8. A device for calculating the mass of molten salt in a molten salt thermal storage system, characterized in that, The molten salt mass calculation device of the molten salt thermal storage system includes: The module for determining the maximum load reduction and peak shaving demand of the molten salt thermal storage system is used to determine the maximum load reduction and peak shaving demand of the molten salt thermal storage system; the molten salt thermal storage system is a molten salt thermal storage system coupled with a thermal power unit. The power consumption and total load reduction rate calculation module is used to calculate the total power consumption of molten salt thermal storage based on the maximum peak load reduction demand of the molten salt thermal storage system, the load reduction rate of the coal-fired boiler, and the unit load reduction rate demand of the thermal power generating unit, and to calculate the total load reduction rate of molten salt based on the load reduction rate of the coal-fired boiler and the unit load reduction rate demand of the thermal power generating unit. The heat storage demand calculation module is used to determine whether the maximum load reduction rate of steam extraction heating is less than the total load reduction rate of molten salt. If so, multi-source heating is carried out through steam extraction heating and electric heater heating. The heat storage demand of electric heater and the heat storage demand of steam extraction heating are calculated based on the ratio of the total power consumption of molten salt heat storage to the power consumption of molten salt heat storage through steam extraction heating and electric heater heating. The molten salt total mass calculation module is used to calculate the total mass of molten salt in a molten salt thermal storage system based on the type of molten salt, molten salt temperature, specific heat capacity of molten salt, heat storage demand of electric heater, and heat storage demand of extraction steam heating.

9. A computer device, comprising: A memory, a processor, and a computer program stored in the memory and capable of running on the processor, characterized in that the processor executes the computer program to implement the method for calculating the molten salt mass of the molten salt thermal storage system according to any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the method for calculating the molten salt mass of the molten salt thermal storage system as described in any one of claims 1-7.

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