CN113283121B - Flow and capacity design method and system for molten salt heat storage industrial steam supply system - Google Patents

Abstract

The invention discloses a flow and capacity design method and system of a molten salt heat storage industrial steam supply system. According to the average deep peak load rate, duration, and external steam supply load statistics of the industrial steam supply power station in the latest natural year value, determine the boundary parameters; and then obtain the correlation characteristics of electric output-steam supply load-unit energy efficiency under the current steam supply mode of the industrial steam supply power station through performance tests, and calculate the steam supply capacity and For the difference of the target steam supply load, take the margin of x from the difference and the duration to design the capacity of the molten salt heat storage device and the process system. The invention conforms to the reality of the engineering site, is suitable for the demonstration of the transformation plan for the flexible supply of heat and electricity in the industrial steam supply power station, and has broad application prospects.

Description

Process and capacity design method and system for molten salt heat storage industrial steam supply system

technical field

The invention belongs to the field of flow and capacity design of a heat storage system, and relates to a process and capacity design method and system for a molten salt heat storage industrial steam supply system.

Background technique

With the gradual advancement of the dual-carbon strategy, the transformation and upgrading of the power energy structure is accelerating, and renewable energy with time-varying characteristics such as wind and light will develop rapidly and become the main source of electric energy. Traditional thermal power optimizes its own positioning, transforms from the main body of electricity to the main body of comprehensive services such as power grid voltage regulation, peak regulation, frequency modulation, and bottom-line guarantee, and promotes a high proportion of new energy power consumption; at the same time, with industrialization and urban With the continuous advancement of the industrialization process, the demand for centralized heat such as industrial steam and residential heating has grown rapidly. From 2015 to 2020, the proportion of wind and light installed capacity increased from 11.3% to 24.31%, thermal power decreased from 65.9% to 49.07%, the average utilization hours decreased by 7.3%, and the central heating area increased by 37.6%. The unit is developing in the direction of large heat-to-electricity ratio and high flexibility.

Affected by climate and geographical conditions, industrial structure and other factors, in some areas the centralized heat consumption is mainly for residential heating, while in other areas the industrial steam supply is the majority. Different from residential heating in the form of hot water, industrial steam supply is affected by the production process, production characteristics, pipeline length, etc. The factory boundary parameters (pressure, temperature, flow) of industrial steam supply power stations vary greatly, and are basically not affected by geographical conditions. Impact. However, industrial steam supply power stations also need to participate in deep peak shaving of the power grid, but the existing thermoelectric decoupling technologies of cogeneration units, such as low-pressure cylinder zero output, high and low pressure bypass, hot water heat storage, electrode heat storage boilers, etc., are all applicable to residents Heating units and industrial steam supply power plants have few mature solutions for heat preservation and power regulation.

Molten salt is an excellent heat transfer and heat storage medium, especially suitable for high temperature conditions, and has been widely used in the fields of solar thermal power generation and high temperature industrial heating. The application of molten salt heat storage to wide-load industrial steam supply for coal-fired power units has been studied.

Literature 1 Luo Haihua, Zhang Houlei, et al. Industrial heating peak-shaving technology for subcritical thermal power units based on molten salt heat storage [J], HVAC, 2020, proposed a set of molten salt heat storage system based on subcritical thermal power unit industrial heating peak-shaving, using recycled The hot steam heats the molten salt to store heat, and when the heat supply is insufficient, the molten salt is used to heat the deoxygenated water to generate industrial steam. The thermal analysis shows that the molten salt heat storage and release system can match the parameters of the thermal system of the thermal power unit to realize the thermoelectric decoupling of the thermal power unit.

Literature 2 Fan Qingwei, Ju Wenping, et al. Research on thermoelectric decoupling of industrial steam supply units based on heat storage process [J], Steam Turbine Technology, 2019 Technology, in view of the thermoelectric decoupling problem of industrial steam supply thermal power units, a new type of "multi-tank-multi-heat exchanger" heat storage was proposed The system, taking a 600MW subcritical unit as an example, designs the flow ratio of steam and molten salt in different stages in stages according to the thermodynamic characteristics in the process of heat storage and release. The calculation results show that the energy consumption loss of the unit during the heat storage process is about 0.30g/(kW) flow ratio of steam and molten salt. It is calculated that during the heat release process, the energy consumption loss of the unit is about 0.02g/(kW) flow ratio of steam and molten salt. During the heat storage process, the energy consumption loss of the unit is about 0.30g/(kW) and the loss is about the flow ratio. It is calculated that during the heat release process, the energy consumption loss of the unit is about 0.02g/(kW) and the loss is about the flow rate distribution MW.

Literature 3 Wang Huijie, Xing Manjiang, et al. Coupling system analysis of heating unit and molten salt heat storage unit based on Aspen Plus [J], Energy Saving, 2019 group, according to the coupling principle of molten salt heat storage unit and heating unit, proposed a coupling scheme for two systems, and built a coupling The simulation model of the system is used to analyze the economy of the coupled system and the ability to respond to load increases. The calculation results show that, compared with the original heating unit, the heat consumption rate of the coupling system has increased by 49.52kJ/(kW.5), 77.26kJ/(kW.2), 75.22kJ/(kW .2) and 56.04kJ/(kW.0), the load response capability of the heating unit has been significantly improved.

Based on a comprehensive analysis of relevant literature, the existing research focuses on thermal system performance modeling, energy consumption changes, and changes in thermal-electrical operating domains of molten salt heat storage systems coupled with coal-fired power units. Capacity design of heat storage system under thermal peak shaving demand.

Contents of the invention

The purpose of the present invention is to solve the problems in the prior art, and provide a flow and capacity design method and system of a molten salt heat storage industrial steam supply system.

In order to achieve the above object, the present invention adopts the following technical solutions to achieve:

A process and capacity design method for a molten salt heat storage industrial steam supply system, comprising the following steps:

Step 1. Statistics of the daily average deep peak load rate α, duration t, and external steam supply load Q _g of the industrial steam supply power station in the latest natural year;

Step 2, obtain the correlation characteristics of the electric output N _ge of the current steam supply mode of the industrial steam supply power station - the steam supply load Q - the energy efficiency characteristic B of the unit through the performance test;

Step 3, according to the daily average deep peaking electric load rate α, duration t, and external steam supply load Q _g of the latest natural year, and the electric output N _ge of the current steam supply mode - steam supply load Q - unit energy efficiency characteristic B Design the flow and capacity of molten salt heat storage industrial steam supply system based on the correlation characteristics.

The further improvement of the above method is:

The daily average deep peak load rate α in the latest natural year is as follows:

In the formula, t is the total number of deep peak-shaving hours on a natural day, i is the i-th deep peak-shaving hour segment; N _ge,i is the average power output of the i-th deep peak-shaving hour segment on a certain natural day; m is the natural number of days that the industrial steam supply power station participated in deep peak regulation in the latest natural year, j is the jth natural day of deep peak regulation; N _ge,d is the nameplate power output of the industrial steam supply station;

The total number of daily average deep peak shaving hours t in the latest natural year is as follows:

In the formula, t _j is the number of deep peak shaving hours in the jth natural day participating in deep peak shaving;

External steam supply load Q _g is as follows:

In the formula, Q _g,i is the average steam supply load of the i-th deep peak-shaving hour period on a certain natural day.

The statistics are rounded according to the operating hours and the operating days. If the normal operation of the unit is less than one hour or less than one natural day, the relevant data will not be included.

The correlation characteristics of the electric output _Nge -steam supply load Q-unit energy efficiency characteristic B are obtained according to the following method:

Through on-site performance tests, the correlation characteristics of the external steam supply load Q and power output N _ge of the industrial steam supply power station are as follows:

Q＝{0,Q _max }＝{0,f ₁ (N _ge )} (4)

In the formula, Q _max = f ₁ (N _ge ), which is the maximum steam supply load under electric output;

For a given electric output, the external steam supply load Q of the industrial steam supply power station is adjustable between 0 and Q _max ;

Through the on-site performance test, the correlation characteristics of the electric output N _ge of the industrial steam supply power station - the steam supply load Q - the energy efficiency characteristic B of the unit are as follows:

B＝F ₁ (Q, N _ge ) (5)

Among them, F ₁ is the correlation formula of the electric output N _ge of the industrial steam supply power station - the steam supply load Q - the energy efficiency characteristic B of the unit.

The process is designed according to the following method:

When the industrial steam supply power station adopts the method of extracting steam from a certain place in the thermal cycle to meet the external demand, the steam is introduced from the boiler outlet to the hot resteam pipeline before the entrance of the medium pressure cylinder, enters the industrial steam supply header through the valve group, and then is supplied to the outside; low When the heat resteam pressure of electric load is insufficient, throttling is performed through the steam inlet regulating valve in front of the inlet of the medium pressure cylinder to increase the heat resteam pressure and external steam supply flow;

In the interval of high electric load, when the heat re-extraction steam of the industrial steam supply power station meets the external steam supply and there is still a margin, the heat re-extraction steam is used as the heat source of the molten salt heat storage system; the low-temperature molten salt at the outlet of the low-temperature molten salt storage tank is passed After the low-temperature molten salt booster pump is pressurized, it enters the low-temperature molten salt heat absorber and is heated by hot re-steam, and the heated high-temperature molten salt enters the high-temperature molten salt storage tank for storage; Condensation becomes hydrophobic and enters the deaerator; this is the heat storage process, at this time, the high-temperature molten salt booster pump and the booster pump for steam supply stop running, and the valve group is closed; the low-temperature molten salt in the low-temperature molten salt storage tank is vented, and the high-temperature molten salt The salt storage tank is filled with high-temperature molten salt, and the heat storage process ends;

In the low electric load section of the industrial steam supply power station, when the external steam extraction method in a certain part of the thermal cycle does not meet the external demand, the molten salt heat storage system enters the heat release state as a supplement to the industrial steam supply; the valve group is opened, and the front pump The water is taken from the outlet and enters the high-temperature molten salt radiator after being pressurized by the booster pump for steam supply; the high-temperature molten salt at the outlet of the high-temperature molten salt storage tank is pressurized by the high-temperature molten salt booster pump and then enters the high-temperature molten salt radiator; In the high-temperature molten salt heat radiator, the high-temperature molten salt heats the feed water at the outlet of the pre-pump to the superheated steam state of the external temperature, and then enters the industrial steam supply header and supplies it to the outside; the booster pump for steam supply is equipped with electric frequency conversion, according to The difference between the external industrial steam supply demand pressure and the water supply pressure at the outlet of the front pump adjusts the operating frequency to control the external steam supply pressure.

The capacity is designed according to the following method:

According to formula (4), the maximum steam supply load Q _α under the electric load α×N _ge,d under the deep peak regulation state of the industrial steam supply power station is determined;

Calculate the difference ΔQ between the target steam supply load Q _g and the actual capacity Q _α of the unit in the state of deep peak regulation:

ΔQ＝ _Qg - _Qα (6)

According to the duration t, according to the steam supply load ΔQ of the heat storage system and the running time of a complete heat storage-discharge cycle, the x margin is taken respectively, and the capacity design of the industrial steam supply system for molten salt heat storage is carried out. The total capacity M _msa is represented, see formula (7); the maximum external steam supply load of the industrial steam supply system for molten salt heat storage is characterized by (1+x)×ΔQ;

In the formula, h _g , h _gs , h _hsa , h _csa are respectively the enthalpy value of industrial steam supply, the enthalpy value of water supply at the outlet of the pre-pump, the enthalpy value of molten salt at the outlet of the high-temperature molten salt storage device, and the molten salt at the inlet of the low-temperature molten salt storage device Enthalpy; η _st is the capacity coefficient of the molten salt storage device to ensure the safe and stable operation of the device;

In a complete cycle of the molten salt heat storage system from heat storage to heat release, the heat loss due to heat dissipation is characterized by the coefficient η _em , and the steam flow m _rh of the heat source is as follows:

m _rh ×(h _rh -h _ss )＝m _msa ×(h _hsa -h _csa )×(1+η _em ) (8)

According to (1+x)×m _rh , M _msa , (1+x)×m _msa flow rate and parameters of steam and molten salt working medium, the equipment and piping system design of the molten salt heat storage system is carried out, and the x mentioned above is considered Due to the further increase in installed capacity and power generation of renewable energy such as wind and solar, the load rate of deep peak shaving power plants for coal-fired industrial steam supply power stations has further decreased and the daily average deep peak shaving time has further increased. The capacity of the molten salt heat storage system and Margin factor taken during runtime design.

The method for determining the margin coefficient x is as follows:

Retrieve the average utilization hours data of renewable energy such as wind and wind in the power grid where the coal-fired industrial steam supply power station is located in the past five years, H ₁ , H ₂ , H ₃ , H ₄ , H ₅ ; calculate the average utilization hours according to formula (9) Number increase rate y:

Taking the year when the molten salt heat storage system is added as the base year, taking into account the deep peak load rate and duration increment of the next three years, calculate the deep peak load N _ge-f of the unit in the fourth year according to formula (10) :

N _ge-f =α×N _ge-d ×(1-y) ³ (10)

According to formula (4), calculate the maximum steam supply capacity difference ΔQ _y between the deep peak-shaving electric load α×N _ge,d in the base year and the deep peak-shaving electric load N _ge-f of the unit in the fourth year, and calculate the margin coefficient x :

A process and capacity design system for a molten salt heat storage industrial steam supply system, including:

A data statistics module, the data statistics module is used to count the daily average deep peak load rate α, the duration t, and the external steam supply load Q _g of the industrial steam supply power station in the last natural year;

A correlation characteristic calculation module, the correlation characteristic calculation module obtains the correlation characteristics of the electric output _Nge -steam supply load Q-unit energy efficiency characteristic B of the current steam supply mode adopted by the industrial steam supply power station through a performance test;

Process and capacity design module, the process and capacity design module is based on the daily average deep peaking electric load rate α, duration t, external steam supply load Q _g and electric output N _ge of the current steam supply mode in the latest natural year -Steam supply load Q-the correlation characteristics of unit energy efficiency characteristics B Design the flow and capacity of molten salt heat storage industrial steam supply system.

A terminal device includes a memory, a processor, and a computer program stored in the memory and operable on the processor, and the processor implements the steps of the above method when executing the computer program.

A computer-readable storage medium, the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above-mentioned method are realized.

Compared with the prior art, the present invention has the following beneficial effects:

The present invention determines the boundary parameters according to the average deep peak load rate, duration, and external steam supply load statistics of the last natural year of the industrial steam supply power station; and then obtains the current steam supply mode of the industrial steam supply power station through performance testing means According to the correlation characteristics of power output-steam supply load-unit energy efficiency, the difference between the steam supply capacity and the target steam supply load of the industrial steam supply power station during the deep peak regulation period is calculated; the steam supply capacity difference and the duration are respectively taken as x Surplus, carry out the design of molten salt heat storage device capacity and process system. The invention conforms to the reality of the engineering site, is suitable for the demonstration of the transformation plan for the flexible supply of heat and electricity in the industrial steam supply power station, and has broad application prospects.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and thus It should be regarded as a limitation on the scope, and those skilled in the art can also obtain other related drawings based on these drawings without creative work.

Fig. 1 is a flow chart of the process flow and capacity design method of the molten salt heat storage industrial steam supply system of the present invention.

Fig. 2 is a structural diagram of the molten salt heat storage industrial steam supply system of the present invention.

Among them: 1-boiler, 2-high pressure cylinder, 3-medium pressure cylinder, 4-low pressure cylinder, 5-condenser, 6-condensate pump, 7-low pressure heater group, 8-deaerator, 9-front Pump, 10-feed water pump, 11-high pressure heater group, 12-high temperature molten salt storage tank, 13-high temperature molten salt booster pump, 14-high temperature molten salt radiator, 15-low temperature molten salt storage tank, 16- Low-temperature molten salt booster pump, 17-low-temperature molten salt heat absorber, 18-boost pump for steam supply, 19-industrial steam supply header, 20-inlet steam regulating valve, 21-23-valve group.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. The components of the embodiments of the invention generally described and illustrated in the figures herein may be arranged and designed in a variety of different configurations.

Accordingly, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

It should be noted that like numerals and letters denote similar items in the following figures, therefore, once an item is defined in one figure, it does not require further definition and explanation in subsequent figures.

In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "horizontal", "inside" etc. is based on the orientation or positional relationship shown in the drawings , or the orientation or positional relationship that the product of the invention is usually placed in use is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation or be constructed in a specific orientation and operation, and therefore should not be construed as limiting the invention. In addition, the terms "first", "second", etc. are only used for distinguishing descriptions, and should not be construed as indicating or implying relative importance.

In addition, when the term "horizontal" appears, it does not mean that the part is required to be absolutely horizontal, but may be slightly inclined. For example, "horizontal" only means that its direction is more horizontal than "vertical", and it does not mean that the structure must be completely horizontal, but can be slightly inclined.

In the description of the embodiments of the present invention, it should also be noted that, unless otherwise specified and limited, the terms "setting", "installation", "connection" and "connection" should be interpreted in a broad sense, for example, It can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention according to specific situations.

The present invention is described in further detail below in conjunction with accompanying drawing:

Referring to Fig. 1, the embodiment of the present invention discloses a flow and capacity design method of a molten salt heat storage industrial steam supply system, including the following steps:

Step 1. Basic data statistics and sorting. Calculate the daily average deep peak load rate α, duration t, and external steam supply load Q _g of industrial steam supply power stations in the latest natural year.

The statistics are rounded up according to the running hours and the running days, and the relevant data will not be included if the normal operation of the unit is less than one hour or less than one natural day.

See formula (1) for the daily average deep peak load rate α in the most recent natural year.

In the formula, t is the total number of deep peak shaving hours on a certain natural day, and i is the ith deep peak shaving hour period. N _ge,i is the average power output of the i-th deep peak-shaving hour on a natural day, MW.

m is the number of natural days that the industrial steam supply power station participated in deep peak regulation in the latest natural year, and j is the natural day of the jth deep peak regulation. N _ge,d is the power output on the nameplate of the industrial steam supply power station, MW.

See formula (2) for the daily average deep peak shaving hours t in the most recent natural year.

In the formula, t _j is the number of deep peak shaving hours in the jth natural day participating in deep peak shaving.

External steam supply load Q _g is determined according to formula (3).

In the formula, Q _g,i is the average steam supply load of the i-th deep peak-shaving hour on a certain natural day, t/h.

Step 2. Obtain the correlation characteristics of the electric output N _ge -steam supply load Q-unit energy efficiency characteristic B of the industrial steam supply power station adopting the current steam supply mode by means of performance test.

Under the dual supply conditions of electricity output N _ge and external steam supply load Q in the industrial steam supply power station, the total amount of fuel consumed by the unit can reflect the overall energy efficiency of the thermal cycle, which is indicated by the standard coal consumption B.

Through the technical means of on-site performance testing, the correlation characteristics of the external steam supply load Q of the industrial steam supply power station with the power output N _ge are obtained, see formula (4).

Q＝{0,Q _max }＝{0,f ₁ (N _ge )} (4)

In the formula, Q _max = f ₁ (N _ge ), which is the maximum steam supply load under electric output, t/h.

For a given electric output, the external steam supply load Q of the industrial steam supply power station is adjustable between 0 and Q _max .

Through the technical means of on-site performance test, the correlation characteristics of electric output N _ge of industrial steam supply power station - steam supply load Q - unit energy efficiency characteristic B are obtained, see formula (5).

B＝F ₁ (Q, N _ge ) (5)

Step 3. Design the flow and capacity of the industrial steam supply system for molten salt heat storage.

1) Process design

As shown in Figure 2, when the industrial steam supply power station adopts the method of extracting steam from a certain place in the thermal cycle to meet external demand, steam is introduced from the hot resteam pipeline from the outlet of the boiler 1 to the inlet of the medium-pressure cylinder 3, and enters the industrial steam through the valve group 22. After supplying the steam header 19, it is externally supplied. When the heat re-steam pressure is insufficient under low electrical load, the steam inlet regulating valve 20 before the inlet of the medium-pressure cylinder 3 is throttled to increase the heat re-steam pressure and external steam supply flow.

In the interval of high electric load, when the heat re-extraction steam of the industrial steam supply power station meets the external steam supply and there is still a margin, the heat re-extraction steam is extracted as the heat source of the molten salt heat storage system. The low-temperature molten salt at the outlet of the low-temperature molten salt storage tank 15 is pressurized by the low-temperature molten salt booster pump 16, and then enters the low-temperature molten salt heat absorber 17 to be heated by heat and then steam, and the heated high-temperature molten salt enters the high-temperature molten salt storage tank 12 storage. The hot re-steam condenses into water after the heat release in the low-temperature molten salt heat absorber 17, and enters the deaerator 8. This is a heat storage process. At this time, the high-temperature molten salt booster pump 13 and the steam supply booster pump 18 stop running, and the valve group 23 is closed. The low-temperature molten salt in the low-temperature molten salt storage tank 15 is emptied, and the high-temperature molten salt storage tank 12 is filled with high-temperature molten salt, and the heat storage process ends.

In the low electric load section of the industrial steam supply power station, when the external supply method of steam extraction somewhere in the thermal cycle does not meet the external demand, the molten salt heat storage system enters the heat release state as a supplement for industrial steam supply. The valve group 23 is opened, water is taken from the outlet of the front pump 9, and enters the high-temperature molten salt radiator 14 after being pressurized by the booster pump 18 for steam supply. The high-temperature molten salt at the outlet of the high-temperature molten salt storage tank 13 enters the high-temperature molten salt radiator 14 after being pressurized by the high-temperature molten salt booster pump 13 . In the high-temperature molten salt radiator 14, the high-temperature molten salt heats the feed water at the outlet of the front pump 9 to the superheated steam state at the external temperature, enters the industrial steam supply header 19, and then supplies it to the outside. The booster pump 18 for steam supply is equipped with electric frequency conversion, and the operating frequency is adjusted according to the difference between the external industrial steam supply demand pressure and the water supply pressure at the outlet of the front pump 9 to control the external steam supply pressure.

2) Capacity design

According to formula (4), the maximum steam supply load Q _α under the electric load α×N _ge,d under the deep peak regulation state of the industrial steam supply power station is determined.

Calculate the difference ΔQ between the target steam supply load Q _g and the actual capacity Q _α of the unit in the state of deep peak regulation, see formula (6).

ΔQ＝ _Qg - _Qα (6)

According to the duration t, the margin coefficient x is taken according to the steam supply load ΔQ of the heat storage system and the running time of a complete heat storage-discharge cycle, and the capacity design of the industrial steam supply system for molten salt heat storage is carried out. The total amount of capacity M _msa in is characterized, see formula (7). The maximum external steam supply load of molten salt heat storage industrial steam supply system is characterized by (1+x)×ΔQ.

In the formula, h _g , h _gs , h _hsa , h _csa are respectively the enthalpy value of industrial steam supply, the enthalpy value of water supply at the outlet of the pre-pump, the enthalpy value of molten salt at the outlet of the high-temperature molten salt storage device, and the molten salt at the inlet of the low-temperature molten salt storage device Enthalpy, kJ/kg.

η _st is the capacity coefficient of the molten salt storage device to ensure the safe and stable operation of the device, which is provided by the design and manufacturer of the molten salt storage device.

x In order to consider the further decline in the deep peak load rate of the coal-fired industrial steam supply power station and the further increase of the daily average deep peak shaving time due to the further increase in the installed capacity of renewable energy such as wind and electricity and the further increase in power generation, the molten salt heat storage system The capacity and the margin factor taken during the design of the running time are determined as follows:

Get the average utilization hour data of renewable energy such as wind and wind in the power grid where the coal-fired industrial steam supply power station is located in the past five years, H ₁ , H ₂ , H ₃ , H ₄ , H ₅ . Calculate the average utilization hours increase rate y according to formula (8),

Taking the year when the molten salt heat storage system is added as the base year, taking into account the deep peak load rate and duration increment of the next three years, calculate the deep peak load N _ge-f of the unit in the fourth year according to formula (9) ,

N _ge-f =α×N _ge-d ×(1-y) ³ (9)

According to formula (4), calculate the maximum steam supply capacity difference ΔQ _y between the deep peak-shaving electric load α×N _ge,d in the base year and the deep peak-shaving electric load N _ge-f of the unit in the fourth year, and calculate the margin coefficient x , see formula (10).

The change in the average utilization hours comprehensively indicates the influence of the installed capacity of renewable energy such as wind and solar energy and the increase in power generation on the coal-fired unit. Therefore, the margin index provided by the present invention is representative and conforms to the site.

In a complete heat storage-release cycle, molten salt is used as a heat carrier to transfer heat from steam to industrial steam supply. During the time transfer process, the temperature of the working fluid in the molten salt storage device and auxiliary systems is much higher than the ambient temperature. Therefore, heat loss is generated, which is characterized by the coefficient η _em . Heat source steam flow rate m _rh is calculated according to formula (11).

m _rh ×(h _rh -h _ss )＝m _msa ×(h _hsa -h _csa )×(1+η _em ) (11)

h _rh , h _ss are the resteam enthalpy entering the low-temperature molten salt heat absorber 17 and the hydrophobic enthalpy leaving the low-temperature molten salt heat absorber 17, respectively, kJ/kg.

According to (1+x)×m _rh , M _msa , (1+x)×m _msa flow rate and steam, molten salt and other working medium parameters, the equipment and piping system design of the molten salt heat storage system is carried out.

The embodiment of the present invention discloses a terminal device, including a memory, a processor, and a computer program stored in the memory and operable on the processor. When the processor executes the computer program, the above method is implemented. A step of.

A terminal device provided by an embodiment of the present invention. The terminal device in this embodiment includes: a processor, a memory, and a computer program stored in the memory and operable on the processor. When the processor executes the computer program, the steps in the foregoing method embodiments are implemented. Alternatively, when the processor executes the computer program, the functions of the modules/units in the above device embodiments are realized.

The computer program may be divided into one or more modules/units, which are stored in the memory and executed by the processor to implement the present invention.

The terminal device may be computing devices such as desktop computers, notebooks, palmtop computers, and cloud servers. The terminal device may include, but not limited to, a processor and a memory.

The processor can be a central processing unit (Central Processing Unit, CPU), and can also be other general-purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), off-the-shelf programmable gate arrays (Field- ProgrammableGateArray, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

The memory can be used to store the computer programs and/or modules, and the processor implements the terminal by running or executing the computer programs and/or modules stored in the memory and calling the data stored in the memory various functions of the device.

The embodiment of the present invention discloses a computer-readable storage medium, the computer-readable storage medium stores a computer program, and it is characterized in that, when the computer program is executed by a processor, the steps of the above method are realized.

If the integrated modules/units of the terminal equipment are realized in the form of software function units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the present invention realizes all or part of the processes in the methods of the above embodiments, and can also be completed by instructing related hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer When the program is executed by the processor, the steps in the above-mentioned various method embodiments can be realized. Wherein, the computer program includes computer program code, and the computer program code may be in the form of source code, object code, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, a recording medium, a U disk, a removable hard disk, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM, Read-OnlyMemory), Random access memory (RAM, RandomAccessMemory), electric carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium may be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, computer-readable media Excludes electrical carrier signals and telecommunication signals.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (5)

1. A flow and capacity design method for a molten salt heat storage industrial steam supply system is characterized by comprising the following steps:

step 1, counting the average daily depth peak-regulation electric load rate alpha, the duration t and the external steam supply load Q of the last natural year of the industrial steam supply power station _g ；

Step 2, obtaining the electric output N of the industrial steam supply power station adopting the current steam supply mode through a performance test _ge -steam supply load Q-correlation characteristic of unit energy efficiency characteristic B;

step 3, adjusting peak electric load rate alpha, duration t and external steam supply load Q according to the daily average depth of the last natural year _g And the electric output N of the current steam supply mode _ge Designing the flow and the capacity of the molten salt heat storage industrial steam supply system according to the correlation characteristics of the steam supply load Q and the unit energy efficiency characteristic B;

the daily average depth peak-to-peak electrical load rate α of the last natural year is as follows:

in the formula, i is the ith depth peak regulation small time period; n is a radical of _ge,i Average electric output of the ith depth peak shaving small period of a certain natural day; m is the latest one of industrial steam supply power stationsNatural days participating in deep peak regulation in the year, wherein j is the jth deep peak regulation natural day; n is a radical of _ge,d The electric power is output for the nameplate of the industrial steam supply power station;

daily average depth peak regulation hour total t of the last natural year _ave-d The following were used:

in the formula, t _j The number of depth peak-shaving hours in the jth natural day participating in the depth peak-shaving;

external steam supply load Q _g The following:

in the formula, Q _g,i Average steam supply load of the ith depth peak regulation small time period of a certain natural day;

the statistics is carried out according to the operation hour rounding and the operation day rounding, the unit normally operates for less than one hour or less than one natural day, and relevant data are not taken into account;

the electrical output N _ge -steam supply load Q-correlation characteristic of unit energy efficiency characteristic B is obtained according to the following method:

through field performance test, the external steam supply load Q of the industrial steam supply power station is obtained along with the electric output N _ge The associated characteristics of (a) are as follows:

Q＝{0,Q _max }＝{0,f ₁ (N _ge )} (4)

in the formula, Q _max ＝f ₁ (N _ge ) The maximum steam supply load under the power output is obtained;

for a given power output, the external steam supply load Q of the industrial steam supply station is between 0 and Q _max The distance between the two parts is adjustable;

obtaining the electric output N of the industrial steam supply power station through field performance test _ge -steam supply load Q-correlation characteristic of unit energy efficiency characteristic B as follows:

B＝F ₁ (Q,N _ge ) (5)

wherein, F ₁ Electric output N for industrial steam supply power station _ge -steam supply load Q-correlation of unit energy efficiency characteristic B;

the process is designed according to the following method:

when the industrial steam supply power station adopts a mode of extracting steam at a certain position in thermodynamic cycle and supplying the steam externally to meet external requirements, the steam is introduced from a hot re-steam pipeline from an outlet of the boiler (1) to the front of an inlet of the intermediate pressure cylinder (3) and enters an industrial steam supply header (19) through a valve group (22) and then is supplied externally; when the low-electric load hot reheat steam pressure is insufficient, throttling is carried out through a steam inlet regulating valve (20) in front of an inlet of the intermediate pressure cylinder (3) so as to improve the hot reheat steam pressure and the external steam supply flow;

in a high-power load section, when the heat re-extraction of the industrial steam supply power station has a margin after external steam supply, extracting heat re-extraction steam as a heat source of the molten salt heat storage system; after being pressurized by a low-temperature molten salt booster pump (16), the low-temperature molten salt at the outlet of the low-temperature molten salt storage tank (15) enters a low-temperature molten salt heat absorber (17) to be heated by hot re-steam, and the heated high-temperature molten salt enters a high-temperature molten salt storage tank (12) to be stored; the hot re-steam is condensed into hydrophobic water after being released by the low-temperature molten salt heat absorber (17), and enters the deaerator (8); the heat storage process is carried out, at the moment, the high-temperature molten salt booster pump (13) and the booster pump (18) for steam supply stop running, and the valve group (23) is closed; emptying the low-temperature molten salt in the low-temperature molten salt storage tank (15), fully storing the high-temperature molten salt in the high-temperature molten salt storage tank (12), and ending the heat storage process;

in the low-electricity load interval of the industrial steam supply power station, when the steam extraction external supply mode at a certain position of the thermodynamic cycle does not meet the external requirement, the molten salt heat storage system enters a heat release state to supplement the industrial steam supply; the valve group (23) is opened, water is taken from the outlet of the pre-pump (9), and enters the high-temperature molten salt heat radiator (14) after being pressurized by the steam supply booster pump (18); the high-temperature molten salt at the outlet of the high-temperature molten salt storage tank (12) is pressurized by a high-temperature molten salt booster pump (13) and then enters a high-temperature molten salt heat radiator (14); in the high-temperature molten salt heat radiator (14), the high-temperature molten salt heats the feed water at the outlet of the pre-pump (9) to an overheated steam state with an external required temperature, and the feed water enters the industrial steam supply header (19) and is supplied to the outside; the booster pump (18) for steam supply is in electric frequency conversion configuration, and the operation frequency is adjusted according to the difference between the external industrial steam supply demand pressure and the outlet water supply pressure of the front-mounted pump (9) so as to control the external steam supply pressure;

the capacity is designed according to the following method:

determining the electrical load alpha multiplied by N under the deep peak regulation state of the industrial steam supply power station according to the formula (4) _ge,d Maximum steam supply load Q _α ；

Calculating target steam supply load Q under deep peak regulation state _g And actual capacity Q of unit _α Difference Δ Q of (d):

ΔQ＝Q _g -Q _α (6)

according to the duration t, respectively taking x allowance according to the steam supply load delta Q of the heat storage system and the running time of a complete storage-heat release period, carrying out capacity design on the molten salt heat storage industrial steam supply system, and using the total capacity M in the molten salt storage tank _msa For characterization, see formula (7); the maximum external steam supply load of the molten salt heat storage industrial steam supply system is characterized by (1 + x) multiplied by delta Q;

in the formula, h _g 、h _gs 、h _hsa 、h _csa Respectively obtaining an industrial steam supply enthalpy value, a pre-pump outlet feed water enthalpy value, a high-temperature molten salt storage device outlet molten salt enthalpy value and a low-temperature molten salt storage device inlet molten salt enthalpy value; eta _st A capacity coefficient of the molten salt storage device for ensuring the safe and stable operation of the device;

the heat loss caused by heat dissipation in a complete cycle of self heat storage-heat release of the molten salt heat storage system is calculated by a coefficient eta _em Characterization, heat source steam flow m _rh The following:

m _rh ×(h _rh -h _ss )＝m _msa ×(h _hsa -h _csa )×(1+η _em ) (8)

wherein h is _rh 、h _ss The enthalpy value of hot re-steam entering the low-temperature molten salt heat absorber (17) and the hydrophobic enthalpy value of the low-temperature molten salt heat absorber (17) are respectively;

as shown as (1 + x)m _rh 、M _msa 、(1+x)×m _msa And designing equipment and a pipeline system of the molten salt heat storage system according to flow, steam and molten salt working medium parameters, wherein x is a margin coefficient obtained when the capacity and the running time of the molten salt heat storage system are designed according to the consideration that the deep peak shaving electrical load rate of the coal-fired industrial steam supply power station is further reduced and the daily average deep peak shaving time is further increased due to the fact that the renewable energy installation and the generated energy increment are further accelerated.

2. The flow and capacity design method of the molten salt heat storage industrial steam supply system according to claim 1, characterized in that the determination method of the margin coefficient x is as follows:

the average utilization hour data H of the renewable energy sources of the power grid of the coal-fired industrial steam supply power station in nearly five years is transferred ₁ 、H ₂ 、H ₃ 、H ₄ 、H ₅ (ii) a The average number-of-hours-of-use increase rate y is calculated according to equation (9):

calculating the deep peak-shaving load rate and the duration increment of the unit in the fourth year according to the formula (10) by taking the current year with the additional molten salt heat storage system as a reference year and counting the deep peak-shaving load rate and the duration increment of the unit in the third year _ge-f ：

N _ge-f ＝α×N _ge-d ×(1-y) ³ (10)

Calculating the reference year depth peak-regulation electrical load alpha multiplied by N according to the formula (4) _ge,d And the unit deep peak regulation electric load N of the fourth year _ge-f Maximum steam supply capacity difference value delta Q _y And calculating a residue coefficient x:

3. a flow and capacity design system of a molten salt heat storage industrial steam supply system for realizing the design method of claim 1 or 2, which is characterized by comprising the following steps:

the data statistics module is used for counting the daily average depth peak-load regulation rate alpha, the duration t and the external steam supply load Q of the last natural year of the industrial steam supply power station _g ；

The correlation characteristic calculation module obtains the electric output N of the industrial steam supply power station adopting the current steam supply mode through a performance test _ge -steam supply load Q-correlation characteristic of unit energy efficiency characteristic B;

a flow and capacity design module for adjusting peak electric load rate alpha, duration t and external steam supply load Q according to the average daily depth of the last natural year _g And the electric output N of the current steam supply mode _ge Designing the flow and the capacity of the molten salt heat storage industrial steam supply system according to the correlation characteristics of the steam supply load Q and the unit energy efficiency characteristic B.

4. A terminal device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that the steps of the method according to claim 1 or 2 are implemented when the processor executes the computer program.

5. A computer-readable storage medium, in which a computer program is stored which, when being executed by a processor, carries out the steps of the method according to claim 1 or 2.

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