System for improving variable load capacity of pure condensed coal generator set based on ternary energy storage and supply

Abstract

The invention discloses a system for improving the variable load capacity of a pure condensed coal generator set based on ternary energy storage and supply, and the system comprises a high-quality energy storage small powder bin which is used for screening and storing pulverized coal meeting a target quality condition, and the pulverized coal is used for being supplied to a hearth of the pure condensed coal generator set for combustion so as to heat a working medium in a circulation pipeline of the pure condensed coal generator set; the high-parameter working medium heat accumulator is used for conveying a high-parameter working medium to the circulating pipeline or storing the high-parameter working medium in the circulating pipeline according to the variable load requirement of the pure condensed coal generator set; and the electrochemical energy storage device is used for transmitting electric energy to a grid-connected point of the pure condensed coal generator set or storing the electric energy generated by a generator of the pure condensed coal generator set according to the variable load requirement of the pure condensed coal generator set.

Description

Technical Field

[0001] The present application relates to the field of coal-fired power technology, and in particular to a system for improving the variable load capacity of pure condensing coal-fired power units based on ternary energy storage. Background Art

[0002] The proportion of renewable energy generation in the power grid is increasing day by day, and the defects brought by renewable energy generation, such as large volatility, high randomness and strong intermittency, are also constantly manifesting. One way to deal with this problem is to use coal-fired power units to play the role of regulators. When faced with load fluctuations, coal-fired power units can be used to quickly adjust the power supply load to meet the stable power demand of users.

[0003] Coal-fired power units include combined heat and power (CHP) coal-fired power units and pure condensing coal-fired power units. For combined heat and power (CHP) units, their load change rate can be significantly improved through thermal-electric decoupling transformation, thereby enhancing the flexibility and responsiveness of the power system. However, for pure condensing units, their load change rate cannot be improved through thermal-electric decoupling transformation. The unit's flexible performance is usually limited (only 1.0-1.5% Pe / min), which cannot meet the needs of rapid load changes. Summary of the invention

[0004] In order to solve the problem of poor rapid load change capability of pure condensing coal power units, the present application discloses the following technical solutions:

[0005] In a first aspect, the present application provides a system for improving the variable load capacity of a pure condensing coal-fired power unit based on ternary energy storage, comprising:

[0006] A high-quality energy storage small powder silo is used to screen and store coal powder that meets the target quality conditions. The coal powder is used to supply the furnace of the pure condensing coal power unit for combustion to heat the working medium in the circulation pipeline of the pure condensing coal power unit;

[0007] A high-parameter working fluid heat accumulator, used to deliver high-parameter working fluid to the circulation pipeline or store high-parameter working fluid in the circulation pipeline according to the variable load demand of the pure condensing coal power unit;

[0008] The electrochemical energy storage device is used to transmit electric energy to the grid connection point of the pure condensing coal power unit according to the variable load demand of the pure condensing coal power unit, or to store the electric energy generated by the generator of the pure condensing coal power unit.

[0009] Optionally, the high-quality energy storage small powder silo includes a coal quality laser online detector, a flexible grading separator and a small powder silo;

[0010] The coal quality laser online detector is used to detect whether the coal powder produced by the coal mill meets the target quality conditions;

[0011] The flexible grading separator is used to transport the pulverized coal meeting the target quality conditions to the small pulverized coal bin;

[0012] The small pulverized coal bin is used to store pulverized coal that meets the target quality conditions.

[0013] Optionally, the high-parameter working fluid heat accumulator includes a high-parameter working fluid heat storage tank, a first liter load steam supply valve, a second liter load steam supply valve and a third liter load steam supply valve;

[0014] The first load steam supply valve is used to transport the high-parameter working fluid that meets the rated operating parameters from the circulation pipeline at the inlet of the superheater of the pure condensing coal-fired power unit to the high-parameter working fluid heat storage tank for storage;

[0015] The second load-raising steam supply valve is used to transport the high-parameter working medium that does not meet the rated operating parameters and is stored in the high-parameter working medium heat storage tank to the circulation pipeline at the drum outlet of the pure condensing coal power unit;

[0016] The third load steam supply valve is used to transport the high-parameter working fluid that does not meet the rated operating parameters and is stored in the high-parameter working fluid heat storage tank to the circulation pipeline at the inlet of the furnace heat exchanger of the pure condensing coal power unit.

[0017] Optionally, the high-parameter working fluid heat accumulator further includes a load-reducing water storage valve;

[0018] The load reduction water storage valve is used to transport the low-parameter working fluid output from the steam drum to the high-parameter working fluid heat storage tank when the pure condensing coal-fired power unit is load reduced.

[0019] Optionally, a heater is provided on the high-parameter working fluid heat storage tank;

[0020] The heater is used to utilize the heat energy of the furnace to heat the working fluid stored in the high-parameter working fluid heat storage tank.

[0021] Optionally, the electrochemical energy storage device is used for:

[0022] When the current load of the pure condensing coal power generation unit is lower than the target load, transmitting electric energy to the grid connection point of the pure condensing coal power generation unit;

[0023] When the current load of the pure condensing coal power generation unit is higher than the target load, the electric energy generated by the generator of the pure condensing coal power generation unit is stored.

[0024] Optionally, the electrochemical energy storage device is used to transmit electric energy to the grid connection point of the pure condensing coal power unit according to the load increase demand within a first time period after determining that the pure condensing coal power unit has a load increase demand;

[0025] The high-parameter working medium heat accumulator is used to deliver the high-parameter working medium to the circulation pipeline in a second time period after the first time period;

[0026] The high-quality coal powder storage small bin is used to provide stored coal powder that meets the target quality conditions to the furnace of the pure condensing coal power generation unit in a third time period after the first time period. The start time of the third time period is later than the start time of the second time period, and the end time of the third time period is later than the end time of the second time period.

[0027] The beneficial effects of this application are:

[0028] When the load needs to be increased, the electrochemical energy storage device can quickly provide electrochemical energy in this solution, quickly but briefly undertake the task of energy supply for the unit; at the same time, the high-parameter working fluid stored in the high-parameter working fluid tank and the unit's working fluid can provide combined energy to quickly increase the parameters and flow of the steam-water system and continue to increase the load; at the same time, the high-quality energy storage small powder bin stores high-quality coal powder in advance and cooperates with the pulverizer to continuously increase the amount of coal fed into the furnace for combustion to supply energy for the unit; the three work together to meet the unit's needs for rapid load increase over a large range and continuously in all stages. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0030] Figure 1 This is an energy flow diagram of a pure condensing coal power unit provided in an embodiment of the present application;

[0031] Figure 2 It is a structural schematic diagram of a system for improving the variable load capacity of a pure condensing coal-fired power unit based on ternary energy storage provided in an embodiment of the present application;

[0032] Figure 3 A schematic diagram of the structure of a high-quality energy storage small powder bin provided in an embodiment of the present application;

[0033] Figure 4 A schematic diagram of the structure of the high-parameter working fluid heat accumulator provided in this embodiment and its connection relationship with the circulation pipeline. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0035] In order to facilitate the understanding of the technical solution of this application, first combine Figure 1 Explain the energy flow direction and response time of coal-fired pure condensing units.

[0036] Figure 1 This is the energy flow diagram of a pure condensing coal power unit. It is understandable that each step of energy flow has a certain inherent lag, which is also the source of the problem that the unit's coal powder response, steam-water response, and power generation response time are inconsistent and difficult to match. Therefore, under the same proportion of energy supply, if the various energy storage methods are ranked according to the unit's response time, the inevitable result is that from fast to slow, they are electrochemical energy storage, mechanical energy storage that can be quickly converted into electrical energy, thermal energy storage that exchanges heat with the unit's working fluid, and coal powder chemical energy storage methods such as small powder silos.

[0037] The various energy storage methods are analyzed below.

[0038] First, electrochemical energy storage and mechanical energy storage methods. Commonly used specific energy storage methods include batteries, air compression energy storage, flywheel energy storage technology, etc. Its advantage is that energy storage can be converted into power generation very quickly, and theoretically can achieve extremely fast load change rate and high energy utilization efficiency of the unit. However, its disadvantage is not only that it is weak in the post-load stage, but also that the energy storage components are completely disconnected from the boiler and fuel supply system. In other words, these energy storage methods are actually real-line energy storage relative to the external system (relative to pure condensing coal-fired power units).

[0039] However, the amount of energy stored in the external system is limited after all, and the problem of "the unit is fast but the boiler is slow" may easily occur during rapid load increases. That is, the load capacity of the unit increases but the load of the boiler steam-water system cannot keep up, resulting in the unit being unable to achieve continuous load increases or being unable to maintain the load for a long time after the load is increased, which poses certain safety hazards.

[0040] Second, thermal energy storage methods. The more mature technology at present is molten salt heat storage technology. Through large-scale heat exchange between molten salt and the unit working fluid, the parameters of the steam-water system in the boiler can be synergistically improved during the unit load increase process, which can avoid the problem of "fast machine and slow furnace" to a certain extent. However, molten salt heat storage technology involves a heat exchange process, which leads to a certain heat exchange delay time, and the energy utilization efficiency is low. Therefore, the load change rate potential is lower than that of electrochemical energy storage and mechanical energy storage technology. In addition, in the rapid load change process, it is required to consider the thermal stress and fatigue damage of the insulation material during heat exchange.

[0041] Third, the pulverizing system stores the chemical energy of coal powder, which is at the bottom of the energy flow of the coal-fired power unit, so the response time to the corresponding unit load is also the longest. However, its defect is that it is difficult to meet the initial unit load increase requirements, and if the unit is only able to quickly change its load by storing the chemical energy of coal powder in the pulverizing system, it will not only cause the furnace combustion to fluctuate violently, causing safety hazards such as instability of the drum water level and high thermal stress in thick-walled components, but it will also be more difficult to accurately control the load curve of the unit, and problems such as "fast furnace and slow machine" and "excessive overshoot" are prone to occur.

[0042] In order to solve the defects of the above single energy storage method, the present application provides Figure 2 The system shown is based on ternary energy storage to improve the variable load capacity of pure condensing coal-fired power units. The system provided in the embodiment of the present application has been verified to be able to form millisecond-level electrochemical energy storage devices to store electricity, ten-second-level high-parameter working fluid heat storage, and minute-level high-quality coal powder chemical energy storage, ultimately achieving the goal of improving the flexibility of the pure condensing unit's 5% Pe variable load rate.

[0043] Specifically, the system may include a high-quality energy storage small powder bin 201 , a high-parameter working fluid heat accumulator 202 and an electrochemical energy storage device 203 .

[0044] The electrochemical energy storage device of this embodiment may be a lithium battery energy storage device or other electrochemical energy storage devices.

[0045] The high-quality energy storage small powder bin 201 is used to screen and store pulverized coal that meets the target quality conditions. The pulverized coal is used to supply the furnace of the pure condensing coal power unit for combustion to heat the working medium in the circulation pipeline of the pure condensing coal power unit.

[0046] The high-parameter working medium heat accumulator 202 is used to deliver the high-parameter working medium to the circulation pipeline or store the high-parameter working medium in the circulation pipeline according to the variable load requirements of the pure condensing coal power unit;

[0047] The electrochemical energy storage device 203 is used to transmit electric energy to the grid connection point of the pure condensing coal power unit according to the variable load demand of the pure condensing coal power unit, or to store the electric energy generated by the generator of the pure condensing coal power unit.

[0048] The beneficial effects of this embodiment are:

[0049] When the load needs to be increased, this solution can quickly provide electrochemical energy from the lithium battery and temporarily undertake the unit energy supply task. After the lithium battery has supplied energy for a period of time, the high-parameter working fluid stored in the high-parameter working fluid tank and the unit working fluid will provide combined energy to quickly increase the parameters and flow of the steam-water system. Finally, the high-quality energy storage small powder bin will store high-quality coal powder in advance and cooperate with the pulverizer to continuously increase the coal feed into the furnace for combustion to supply energy to the unit, thereby meeting the unit's needs for rapid load increase over a large range and continuously in all stages.

[0050] Furthermore, the system of this embodiment can also achieve the goal of consistency in motor and furnace load increase by optimizing and collaboratively controlling the energy configuration and response curve of each unit, thereby solving the key problems of "fast machine and slow furnace", "fast furnace and slow machine", and mismatched unit response times.

[0051] The structure of the high-quality energy storage small powder silo 201 can be as follows Figure 3 shown.

[0052] The high-quality energy storage small powder silo can include a coal quality laser online detector, a flexible grading separator, an air-powder mixer, a pulverized coal burner, a small powder silo for an exhaust gas burner, a separator, an exhaust gas fan, a fan and a hot primary air main pipe.

[0053] Among them, the exhaust gas burner and the pulverized coal burner are connected to the furnace, the fan coal quality laser online detector is connected to the outlet of the coal mill, the inlet of the coal mill is connected to the coal feeder, and the coal feeder is equipped with a raw coal bunker. The connection relationship of other components is as follows: Figure 3 As shown, no further elaboration is required.

[0054] When the high-quality energy storage small powder bin is working, the fan can blow the pulverized coal from the pulverizer to the coal quality laser online detector through the hot primary air main pipe.

[0055] The coal quality laser online detector is used to detect whether the coal powder produced by the coal mill meets the target quality conditions.

[0056] The coal quality laser online detector can detect the quality of coal powder based on laser induced breakdown spectroscopy technology (LIBS technology), and can also detect the quality of coal powder based on other detection technologies, without limitation.

[0057] Taking the detection of coal powder quality based on laser induced breakdown spectroscopy (LIBS) technology as an example, the coal quality laser online detector can use a laser beam to irradiate the substance to be tested, that is, the coal powder transported to the coal quality laser online detector, so that it generates high-temperature plasma, and collects the characteristic spectrum signal of the plasma after a certain delay time. The quality index of the coal powder can be analyzed based on the collected characteristic spectrum signal. This is a non-destructive and rapid detection technology that does not require sampling or chemical treatment of the sample, and can obtain analysis results within a few seconds. Therefore, it is very suitable for completing the task of online detection of coal quality.

[0058] In this embodiment, the coal powder meets the target quality condition, which means that the quality index of the coal powder falls within the corresponding qualified interval. Correspondingly, if the quality index of the coal powder does not fall within the corresponding qualified interval, it can be determined that the coal powder delivered at this time does not meet the target quality condition.

[0059] There can be multiple quality indicators of coal powder, without limitation. As an example, the quality indicator of coal powder may include the impurity content in the coal powder. In this case, the qualified interval of the impurity content may be greater than or equal to 0 and less than or equal to the impurity content threshold.

[0060] The flexible grading separator is used to transport the pulverized coal that meets the target quality conditions to the small pulverized coal silo.

[0061] The small powder silo is used to store coal powder that meets the target quality conditions.

[0062] Specifically, if the coal quality laser online detector detects that the current coal powder meets the target quality conditions, the flexible classification and sorting device can control Figure 3 Valve 1 is opened to a certain opening, and valve 2 is adjusted downward at the same time, so that a certain amount of pulverized coal meeting the target quality conditions is transported to the small pulverized coal bin through valve 1.

[0063] Among them, the opening of valve 1 and the opening of valve 2 can be determined according to the load of the pure condensing coal power unit. For example, when the load is high and the generator of the pure condensing coal power unit needs to output more electric energy, valve 2 can have a larger opening and valve 1 can have a smaller opening, thereby ensuring the coal powder supply to the furnace; when the load is low and the generator of the pure condensing coal power unit needs to output less electric energy, valve 2 can have a smaller opening and valve 1 can have a larger opening, thereby storing more coal powder that meets the target quality conditions in the small powder bin.

[0064] Optionally, when the storage capacity of the small powder bin reaches the upper limit, that is, when it is full of coal powder that meets the target quality conditions, the flexible classification separator can maintain Figure 3 Valve 1 is closed, and the coal quality laser online detector can stop working at the same time, until a part of the coal powder stored in the small powder bin is consumed, and the flexible grading separator and the coal quality laser online detector will then transport the coal powder that meets the target quality conditions to the small powder bin in the above manner.

[0065] When the pure condensing coal power unit needs to increase its load, the flexible grading and sorting device can close valve 1 to deliver the full amount of coal powder to the furnace for combustion. At the same time, the exhaust gas fan can start working and use the exhaust gas after combustion in the furnace to blow the coal powder stored in the small powder bin into the furnace. This can quickly increase the mass flow rate of coal powder entering the furnace, thereby increasing the heat energy output by the furnace, and ultimately achieving the effect of increasing the current load of the generator of the pure condensing coal power unit.

[0066] At the same time, when the load needs to be increased to the target load, the control system of the pure condensing coal power unit will control the pulverized coal output by the pulverizer to gradually increase. When the mass flow rate of the pulverized coal output by the pulverizer increases to match the target load of the pure condensing coal power unit, the exhaust gas fan can stop working, thereby stopping the pulverized coal in the small powder bin from being fed into the furnace.

[0067] When the pure condensing coal power unit needs to reduce its load to the target load, the flexible grading separator can increase the opening of valve 1 and reduce the opening of valve 2 on the premise that the coal powder quality meets the target quality conditions. At the same time, the exhaust gas fan does not work. This can quickly reduce the mass flow rate of coal powder entering the furnace, thereby reducing the heat energy output by the furnace, and ultimately achieve the effect of increasing the current load of the generator of the pure condensing coal power unit.

[0068] At the same time, when the load needs to be reduced, the control system of the pure condensing coal power unit will control the coal powder output of the pulverizer to gradually reduce. When the mass flow rate of the coal powder output by the pulverizer is reduced to match the target load of the pure condensing coal power unit, valve 1 can be completely closed, or closed to a smaller opening, so that all or most of the coal powder output by the pulverizer is input into the furnace for combustion.

[0069] According to the analysis of the energy flow of coal-fired pure condensing units, it can be seen that improving the unit's coal powder response capability is an important guarantee for achieving the consistency of the unit's boiler load increase. The high-quality small powder silo uses the coal quality laser online detection device to realize coal quality online detection technology and flexible sorting, which can store high-quality coal powder in advance to adjust the unit's coal supply curve and optimize the fuel storage and supply mechanism; at the same time, when the unit is loaded, the coal powder quality is enhanced, the combustion in the furnace is strengthened, and the goal of reducing the coal powder response time is finally achieved.

[0070] The response characteristics of the steam-water system are not only one of the main factors affecting the variable load rate capability of the unit, but are also directly related to the safe operation of the equipment and the life safety of personnel. In this embodiment, the high-parameter working fluid heat accumulator can store high-parameter working fluids with the same working fluid parameters as the rated load of the unit through the high-parameter working fluid heat storage tank, and when the load is increased, it can be combined with the working fluid of the unit to quickly increase the parameters and flow of the steam-water system, so that it can provide additional mechanical energy for the steam turbine to drive the generator to achieve additional power generation, thereby achieving the goal of rapid load increase of the unit.

[0071] For details, see Figure 4 , which is a schematic diagram of the structure of the high-parameter working fluid heat accumulator provided in this embodiment and its connection relationship with the circulation pipeline. It can be seen that the high-parameter working fluid heat accumulator includes a high-parameter working fluid heat storage tank, a first liter load steam supply valve, a second liter load steam supply valve and a third liter load steam supply valve.

[0072] The first load steam supply valve is connected to the pipeline at the superheater inlet of the pure condensing coal power unit; the second load steam supply valve is connected to the pipeline at the drum outlet of the pure condensing coal power unit; the third load steam supply valve is connected to the pipeline at the furnace heat exchanger inlet of the pure condensing coal power unit.

[0073] The first load steam supply valve is used to transport high-parameter working fluid that meets the rated operating parameters from the circulation pipeline at the inlet of the superheater of the pure condensing coal-fired power unit to the high-parameter working fluid heat storage tank for storage;

[0074] The second load steam supply valve is used to transport the high-parameter working fluid that does not meet the rated operating parameters stored in the high-parameter working fluid heat storage tank to the circulation pipeline at the drum outlet of the pure condensing coal power unit;

[0075] The third load steam supply valve is used to transport the high-parameter working fluid that does not meet the rated operating parameters stored in the high-parameter working fluid heat storage tank to the circulation pipeline at the inlet of the furnace heat exchanger of the pure condensing coal power unit.

[0076] Optionally, the high-parameter working fluid heat accumulator further includes a load-reducing water storage valve;

[0077] The load reduction water storage valve is connected to the pipeline at the drum outlet. The load reduction water storage valve is used to transport the low-parameter working fluid output from the drum to the high-parameter working fluid heat storage tank when the pure condensing coal-fired power unit is load-reduced.

[0078] In this embodiment, the high-parameter working medium may be a working medium whose temperature parameter and pressure parameter are greater than or equal to the corresponding threshold value, and the low-parameter working medium may be a working medium whose temperature parameter and pressure parameter are less than the corresponding threshold value. The above working medium may be water.

[0079] The working principle of high parameter working fluid heat storage device can be:

[0080] When the unit is at rated power generation load, the first load-raising steam supply valve can transport a portion of the high-parameter working fluid that meets the rated operating parameters entering the superheater inlet to the high-parameter working fluid heat storage tank for storage. At the same time, if the load needs to be reduced, the load-reducing water storage valve can also transport the low-parameter working fluid discharged from the drum outlet to the high-parameter working fluid heat storage tank for storage. In the above manner, the high-parameter working fluid heat storage tank can reduce the flow rate of the working fluid in the circulation pipeline and the heat carried, thereby quickly reducing the flow rate through the turbine, thereby reducing the power generation of the generator, and achieving rapid load reduction.

[0081] The opening degrees of the first load-increasing steam supply valve and the load-reducing water storage valve can be determined according to the load reduction requirements. If a large load reduction is required, the two valves can be opened to a larger opening degree. If a small load reduction is required, the two valves can be opened to a smaller opening degree.

[0082] Furthermore, when it is necessary to reduce the load to the target load, under the control of the controller of the pure condensing coal-fired power unit, the flow rate and temperature of the high-parameter working fluid output by the furnace heat exchanger can be gradually reduced. When the flow rate and temperature of the high-parameter working fluid output by the furnace heat exchanger are reduced to match the target load of the pure condensing coal-fired power unit, the first load-raising steam supply valve and the load-reducing water storage valve can be closed.

[0083] When the load needs to be increased, the second load-increasing steam supply valve and the third load-increasing steam supply valve can be opened, and the working fluid stored in the high-parameter working fluid heat storage tank can enter the circulation pipeline from the corresponding interface, thereby quickly increasing the flow and heat of the working fluid in the circulation pipeline, thereby quickly increasing the flow through the steam turbine, and then increasing the power generation of the generator, thereby achieving rapid load increase.

[0084] The opening degrees of the second load-increasing steam supply valve and the third load-increasing steam supply valve can be determined according to the load-increasing demand. If a large load-increasing demand is required, these two valves can be opened to a larger opening degree. If a small load-increasing demand is required, these two valves can be opened to a smaller opening degree.

[0085] Furthermore, when it is necessary to increase the load to the target load, under the control of the controller of the pure condensing coal-fired power unit, the flow rate and temperature of the high-parameter working fluid output by the furnace heat exchanger can be gradually increased. When the flow rate and temperature of the high-parameter working fluid output by the furnace heat exchanger are increased to match the target load of the pure condensing coal-fired power unit, the second load-increasing steam supply valve and the third load-increasing steam supply valve can be closed.

[0086] Further optionally, a heater may be provided on the high-parameter working fluid heat storage tank;

[0087] The heater is used to utilize the heat energy of the furnace to heat the working fluid stored in the high-parameter working fluid heat storage tank.

[0088] Specifically, the heater can provide heat for the high-parameter working fluid tank through the combustion of pulverized coal in the furnace, so that the working fluid stored in the high-parameter working fluid tank can quickly reach the rated operating parameters, playing the role of "one furnace and two pots".

[0089] The advantage of the high-parameter working fluid tank is that its scale and energy storage are not large, but when the unit requires load increase, it can bear the energy demand for load increase when coal powder cannot be quickly supplied in a short period of time and the drum pressure and temperature cannot be raised in time, quickly adjust the working fluid circulation state, effectively reduce the impact of boiler thermal inertia, and reduce the response time of the steam-water system. In addition, high-parameter working fluids have two modes of water supply and steam supply, which can quickly provide thermal energy while stabilizing the drum water level through certain control means, thereby improving the safety of the unit when increasing load.

[0090] It should be noted that the system of this embodiment can be applicable to subcritical pure condensing coal power units, and can also be applicable to supercritical pure condensing coal power units. Figure 4 The circulation pipeline shown is the circulation pipeline of a subcritical pure condensing coal power unit. When it is applicable to a supercritical pure condensing coal power unit, Figure 4 The steam drum shown may be replaced by an economizer.

[0091] Optionally, the electrochemical energy storage device is specifically used for:

[0092] When the current load of the pure condensing coal power unit is lower than the target load, electric energy is transmitted to the grid connection point of the pure condensing coal power unit;

[0093] When the current load of the pure condensing coal power generation unit is higher than the target load, the electric energy generated by the generator of the pure condensing coal power generation unit is stored.

[0094] Among them, in the scenario where the load needs to be increased, the current load of the pure condensing coal-fired power unit may be lower than the target load. The more the current load is lower than the target load, the higher the power of the electrochemical energy storage device outputs. The closer the current load is to the target load, the lower the power of the electrochemical energy storage device outputs. If the current load of the generator is increased to the same as the target load, the electrochemical energy storage device stops outputting electricity.

[0095] In a scenario where load reduction is required, the current load of a pure condensing coal-fired power unit may be higher than the target load. The more the current load is higher than the target load, the higher the power of the electrochemical energy storage device absorbing and storing electrical energy from the generator. The closer the current load is to the target load, the lower the power of the electrochemical energy storage device absorbing and storing electrical energy. If the current load of the generator is reduced to the same as the target load, the electrochemical energy storage device stops absorbing and storing electrical energy.

[0096] The lithium battery power storage system has the shortest delay time, and its response time is only in milliseconds. It can be directly connected to the power grid without the need for energy conversion. It is most suitable for completing the energy supply task in the initial stage of load increase of the unit. The high-quality energy storage small powder silo and high-parameter working fluid heat accumulator can provide the output power that is lacking in load increase, buy time for the unit's coal powder response and steam-water response, and further improve the unit's load response capability.

[0097] However, lithium batteries are external energy storage and cannot be coupled with the unit's steam-water system and pulverized coal system to improve the unit's internal parameters. In addition, due to factors such as economic site constraints, the total amount of lithium battery storage is limited, making it difficult to cope with the unit's continuous load increase or assume the main energy supply role during load increase. Therefore, they can only play an emergency energy supply role in the early stage of peak regulation. If the unit is to operate stably for a long time during and after continuous load increase, it is still necessary to rely mainly on high-quality energy storage small powder silos and high-parameter working fluid heat accumulators to further improve the unit's coal powder response and steam-water response capabilities, and ensure the consistency of the unit's boiler load increase.

[0098] The working principles of the three parts in the system of this embodiment are explained below with reference to an example.

[0099] Assume that the current load of the pure condensing coal power unit is X, and now it is necessary to increase the load from X to the target load Y. At this time, the high-quality energy storage small powder bin 201, the high-parameter working fluid heat accumulator 202 and the electrochemical energy storage device 203 all operate according to the working principle when the load needs to be increased. After a period of time, the current load of the generator just reaches the target load Y, but the heat and flow of the working fluid output by the furnace heat exchanger have not yet been increased to a level matching the target load Y. At this time, the electrochemical energy storage device can stop outputting electrical energy, and the high-quality energy storage small powder bin 201 and the high-parameter working fluid heat accumulator 202 continue to operate according to the working principle when the load is increased. The period from the beginning of the load increase to the current load of the generator just reaching the target load Y can be regarded as the early stage of the load increase process.

[0100] After a period of time after the early stage, the heat and flow of the working fluid output by the furnace heat exchanger are just increased to the extent that matches the target load Y. At this time, the high-parameter working fluid regenerator 202 can stop delivering high-parameter working fluid to the circulation pipeline, but the mass flow of the pulverized coal output by the coal mill may not have been increased to the extent that matches the target load Y. Therefore, the high-quality energy storage small powder bin 201 continues to deliver pulverized coal to the furnace. The period from the end of the early stage to the time when the heat and flow of the working fluid are just increased to the extent that matches the target load Y can be regarded as the middle stage of the load increase process.

[0101] After a period of time after the middle stage, the mass flow rate of coal powder output by the pulverizer is finally increased to a level that matches the target load Y. At this point, the high-quality energy storage small powder bin 201 can stop transporting coal powder to the furnace, and the load increase process ends. The period from the end of the middle stage to the end of the load increase process can be regarded as the middle and late stages of the load increase process.

[0102] In another example, assuming that the current load of the pure condensing coal power unit is X, and now it is necessary to reduce the load from X to the target load Z, at this time, the high-quality energy storage small powder bin 201, the high-parameter working fluid heat accumulator 202 and the electrochemical energy storage device 203 all operate according to the working principle when the load is required. After a period of time, the current load of the generator just reaches the target load Z, but the heat and flow of the working fluid output by the furnace heat exchanger have not yet been reduced to a level matching the target load Z. At this time, the electrochemical energy storage device can stop absorbing electrical energy from the generator, and the high-quality energy storage small powder bin 201 and the high-parameter working fluid heat accumulator 202 continue to operate according to the working principle when the load is reduced. The period from the beginning of load reduction to the current load of the generator just reaching the target load Z can be regarded as the early stage of the load reduction process.

[0103] After a period of time after the early stage, the heat and flow of the working fluid output by the furnace heat exchanger just decrease to the extent that matches the target load Z. At this time, the high-parameter working fluid heat accumulator 202 can stop transporting the circulation pipeline to the high-parameter working fluid heat storage tank for storage, but at this time, the mass flow of the pulverized coal output by the coal mill may not have decreased to the extent that matches the target load Z. Therefore, the flexible grading and sorting device of the high-quality energy storage small powder bin 201 continues to input a portion of the pulverized coal output by the coal mill that meets the target quality conditions into the small powder bin to reduce the mass flow of the pulverized coal that finally enters the furnace. The period from the end of the early stage to the time when the heat and flow of the working fluid just decrease to the extent that matches the target load Z can be regarded as the middle stage of the load reduction process.

[0104] After a period of time after the middle stage, the mass flow rate of coal powder output by the pulverizer is finally reduced to a level that matches the target load Z. At this point, the flexible grading separator can stop delivering coal powder to the small bins, and the load reduction process ends. The period from the end of the middle stage to the end of the load reduction process can be regarded as the middle and late stages of the load reduction process.

[0105] In some embodiments, the three parts of the system of this embodiment can also work in coordination according to a certain time rule when variable load is required.

[0106] Taking the case of a pure condensing coal power unit increasing its load as an example, the three parts of the system of this embodiment can cooperate and work in the following manner:

[0107] The electrochemical energy storage device is used to transmit electric energy to the grid connection point of the pure condensing coal power unit according to the load increase demand within the first time period after determining that the pure condensing coal power unit has a load increase demand;

[0108] The high-parameter working medium heat accumulator is used to deliver the high-parameter working medium to the circulation pipeline in a second time period after the first time period, so as to provide additional steam for the pure condensing coal power unit for power generation;

[0109] The high-quality coal powder storage small silo is used to provide the stored coal powder that meets the target quality conditions to the furnace of the pure condensing coal power-grade unit in the third time period after the first time period, so as to continuously increase the amount of coal fed into the furnace for combustion to provide energy for the unit;

[0110] The start time of the third time period is later than the start time of the second time period, and the end time of the third time period is later than the end time of the second time period.

[0111] As some examples, the first time period may be 0 to 10 seconds after it is determined that the pure condensing coal power unit needs to increase its load. This period of time can be regarded as the early stage of the load increase process. The second time period may be 10 minutes from 10 seconds after it is determined that the pure condensing coal power unit needs to increase its load. This period of time can be regarded as the middle stage of the load increase process. The third time period may be 2 to 20 minutes after it is determined that the pure condensing coal power unit needs to increase its load. This period of time can be regarded as the middle and late stage of the load increase process.

[0112] In addition to the aforementioned effects, the system of this embodiment can also solve the hidden dangers of thermal stress and fatigue damage of the insulation material caused by rapid and large-scale heat exchange between the existing energy storage system and the unit working fluid; in addition, the system also has advantages in terms of economy and efficiency.

[0113] Table 1 is a comparison of the economic efficiency of the system technology of this embodiment and various energy storage technologies. It can be seen that whether it is the construction period and investment cost included in the one-time investment, or the efficiency and life of long-term operation, the system of this embodiment has an absolute advantage over other energy storage technologies.

[0114]

[0115] The last two rows of data are estimated values ​​based on experimental verification results. Small powder storage, high temperature water tank storage and lithium-ion batteries are the technologies used in the three parts of the system in this embodiment. Other data sources are related literature in the field of energy storage technology.

[0116] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0117] For the convenience of description, the above system or device is described by dividing it into various modules or units according to its functions. Of course, when implementing the present application, the functions of each unit can be implemented in the same or multiple software and / or hardware.

[0118] It can be known from the description of the above implementation methods that those skilled in the art can clearly understand that the present application can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application can be essentially or partly contributed to the prior art in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in the various embodiments of the present application or certain parts of the embodiments.

[0119] Finally, it should be noted that, in this article, relational terms such as first, second, third and fourth are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0120] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A system for improving the variable load capacity of pure condensing coal power units based on ternary energy storage, characterized in that: include: A high-quality energy storage small powder silo is used to screen and store coal powder that meets the target quality conditions. The coal powder is used to supply the furnace of the pure condensing coal power unit for combustion to heat the working medium in the circulation pipeline of the pure condensing coal power unit; A high-parameter working fluid heat accumulator, used to deliver high-parameter working fluid to the circulation pipeline or store high-parameter working fluid in the circulation pipeline according to the variable load demand of the pure condensing coal power unit; The electrochemical energy storage device is used to transmit electric energy to the grid connection point of the pure condensing coal power unit according to the variable load demand of the pure condensing coal power unit, or to store the electric energy generated by the generator of the pure condensing coal power unit.

2. The system according to claim 1, characterized in that The high-quality energy storage small powder silo includes a coal quality laser online detector, a flexible grading and sorting device and a small powder silo; The coal quality laser online detector is used to detect whether the coal powder produced by the coal mill meets the target quality conditions; The flexible grading separator is used to transport the pulverized coal meeting the target quality conditions to the small pulverized coal bin; The small pulverized coal bin is used to store pulverized coal that meets the target quality conditions.

3. The system according to claim 1, characterized in that The high-parameter working fluid heat accumulator comprises a high-parameter working fluid heat storage tank, a first-liter load steam supply valve, a second-liter load steam supply valve and a third-liter load steam supply valve; The first load steam supply valve is used to transport the high-parameter working fluid that meets the rated operating parameters from the circulation pipeline at the inlet of the superheater of the pure condensing coal-fired power unit to the high-parameter working fluid heat storage tank for storage; The second load-raising steam supply valve is used to transport the high-parameter working medium that does not meet the rated operating parameters and is stored in the high-parameter working medium heat storage tank to the circulation pipeline at the drum outlet of the pure condensing coal-fired power unit; The third load steam supply valve is used to transport the high-parameter working fluid that does not meet the rated operating parameters and is stored in the high-parameter working fluid heat storage tank to the circulation pipeline at the inlet of the furnace heat exchanger of the pure condensing coal power unit.

4. The system according to claim 3, characterized in that The high-parameter working fluid heat accumulator also includes a load-reducing water storage valve; The load reduction water storage valve is used to transport the low-parameter working fluid output from the steam drum to the high-parameter working fluid heat storage tank when the pure condensing coal-fired power unit is load reduced.

5. The system according to claim 4, characterized in that The high-parameter working fluid heat storage tank is provided with a heater; The heater is used to utilize the heat energy of the furnace to heat the working fluid stored in the high-parameter working fluid heat storage tank.

6. The system according to claim 1, characterized in that The electrochemical energy storage device is used for: When the current load of the pure condensing coal power generation unit is lower than the target load, transmitting electric energy to the grid connection point of the pure condensing coal power generation unit; When the current load of the pure condensing coal power generation unit is higher than the target load, the electric energy generated by the generator of the pure condensing coal power generation unit is stored.

7. The system according to claim 1, characterized in that The electrochemical energy storage device is used to transmit electric energy to the grid connection point of the pure condensing coal power unit according to the load increase demand within a first time period after determining that the pure condensing coal power unit has a load increase demand; The high-parameter working medium heat accumulator is used to transport the high-parameter working medium to the circulation pipeline in a second time period after the first time period; The high-quality coal powder storage small bin is used to provide stored coal powder that meets the target quality conditions to the furnace of the pure condensing coal power generation unit in a third time period after the first time period. The start time of the third time period is later than the start time of the second time period, and the end time of the third time period is later than the end time of the second time period.

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