Vacuum heat pipe low-temperature economizer intelligent water quantity control method

Abstract

The present application relates to a kind of vacuum heat pipe low temperature economizer intelligent water quantity control method, specific steps include: by the communication interface of vacuum heat pipe low temperature economizer, obtain the operating parameter of vacuum heat pipe low temperature economizer;According to the heat balance principle, the heat exchange power of vacuum heat pipe low temperature economizer is calculated;According to the thermodynamic principle and equivalent heat drop principle, the heat exchange power of vacuum heat pipe low temperature economizer is used, the new steam equivalent heat drop increase of low-pressure heater heating system is calculated, and the value of new steam equivalent heat drop increase is used as the evaluation standard of flue gas waste heat utilization economic benefit;Based on the dust removal efficiency of dust collector and the low temperature corrosion speed of vacuum heat pipe and the threshold value of hydrophobic pressure of low temperature heater, the cooling water quantity constraint of vacuum heat pipe low temperature economizer is determined, respectively, the cooling water quantity range that meets dust removal efficiency, low temperature corrosion speed, hydrophobic pressure threshold value, while meeting the cooling water quantity range of three threshold values is the best value range.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas treatment, and in particular to an intelligent water volume control method for a vacuum heat pipe low-temperature economizer. Background Art

[0002] The vacuum heat pipe low-temperature economizer works by condensing steam into liquid in the condensing section of the vacuum heat pipe upon contact with the cold wall, releasing latent heat of vaporization. This heat is then transferred through the pipe wall to the cooling water outside the vacuum heat pipe. The condensed working fluid then flows back to the evaporating section under gravity, restarting the evaporation and heat absorption process, repeating the cycle. The cooling water, having absorbed the heat, is then transferred to the low-pressure heating system. This improves thermal efficiency while maintaining constant fuel consumption.

[0003] However, since the electrostatic precipitator has certain requirements for flue gas temperature, high-temperature flue gas increases the fly ash resistivity, easily forming back corona, resulting in a decrease in dust removal efficiency; if the flue gas temperature is too low, low-temperature corrosion is more likely to occur, resulting in a shortened equipment life, so the flue gas temperature at the heat pipe heat exchanger outlet needs to be controlled within a certain range. At the same time, after the cooling water passes through the heat pipe heat exchanger, it will merge with the outlet water of the upper low-pressure heater and enter the lower low-pressure heater. If the cooling water outlet temperature is much lower than the set value, steam extraction operation is required, resulting in energy loss of the low-pressure heater and reducing the thermal efficiency of the high-pressure heating system; if the cooling water outlet temperature is much higher than the set value, it is easy to cause condenser pressure changes, leading to problems such as difficulty in draining water, so the cooling water outlet temperature also needs to be controlled within a certain range.

[0004] Currently, cooling water flow control for vacuum heat pipe low-temperature economizers mostly relies on manual or PID control. Firstly, the inlet flue gas temperature fluctuates significantly depending on factors such as load and coal type, making it difficult to dynamically adjust the cooling water flow in real time. This results in significant fluctuations in the outlet flue gas temperature, which can lead to low-temperature corrosion of the equipment and reduced dust removal efficiency. Secondly, changes in cooling water flow affect not only the flue gas temperature at the heat exchanger outlet but also the outlet water temperature. Manual or traditional PID control typically focuses solely on ensuring that the outlet flue gas temperature meets the setpoint, ignoring the impact of outlet water temperature on the equipment and flue gas waste heat utilization. When the outlet water temperature of the vacuum heat pipe falls below the low-pressure heater's converging point, the temperature differential between the two fluids generates entropy increase, reducing work capacity and thermal efficiency. This requires additional steam extraction, resulting in reduced thermal efficiency for the entire low-pressure heating system. When the outlet water temperature of the vacuum heat pipe exceeds the setpoint, it can easily cause abnormal condenser pressure, leading to equipment failures such as drainage difficulties and failure to achieve optimal equipment operation.

[0005] In the prior art CN112283693A automatic control system and method for flue gas temperature and water temperature in a low-temperature economizer of a thermal power unit, it is disclosed that a PID controller is used to automatically adjust the inlet water temperature and internal flue gas temperature of the low-temperature economizer. However, the above-mentioned problem exists. Manual or traditional PID control generally only focuses on whether the outlet flue gas temperature meets the set value, while ignoring the influence of the outlet water temperature on the equipment and the utilization rate of the flue gas waste heat. Summary of the Invention

[0006] In order to solve the above problems in the prior art, the present invention proposes an intelligent water control method for a vacuum heat pipe low-temperature economizer.

[0007] The technical solutions of the present invention are as follows:

[0008] The present invention proposes an intelligent water flow control method for a vacuum heat pipe low-temperature economizer, which specifically includes the following steps:

[0009] Obtain the operating parameters of the vacuum heat pipe low-temperature economizer through each communication interface of the vacuum heat pipe low-temperature economizer;

[0010] Calculate the heat transfer power of vacuum heat pipe low temperature economizer based on the principle of light and heat balance;

[0011] Based on the principles of thermodynamics and equivalent heat drop, the heat exchange power of the vacuum heat pipe low-temperature economizer is used to calculate the increase in the equivalent heat drop of fresh steam in the low-pressure heater heating system. This value is used as the evaluation standard for the economic benefits of flue gas waste heat utilization.

[0012] Based on the dust removal efficiency of the dust collector, the low-temperature corrosion rate of the vacuum heat pipe, and the low-temperature heater's drain pressure threshold, the cooling water flow constraints for the vacuum heat pipe low-temperature economizer are determined. The cooling water flow range that meets the dust removal efficiency, low-temperature corrosion rate, and drain pressure threshold is determined. The cooling water flow range that meets all three thresholds is the optimal range.

[0013] By setting weight parameters, the final value range of the cooling water volume is ensured to be non-empty, and when the values ​​of dust removal efficiency, low-temperature corrosion rate, and hydrophobic pressure reach critical values, the value range of the cooling water volume is automatically adjusted to keep it within the optimal value range;

[0014] Based on the optimal range of the equivalent heat drop increase of fresh steam and the cooling water volume of the low-pressure heater heating system, a divide-and-conquer algorithm is used to recursively solve the optimal real-time value of the cooling water volume.

[0015] The function of cooling water volume and the opening of the electric regulating valve of the water inlet pipe is fitted according to historical data, and the opening of the electric regulating valve of the water inlet pipe is dynamically adjusted based on the optimal real-time value of cooling water volume.

[0016] As a preferred embodiment, the operating parameters include the flue gas inlet and outlet flue gas temperatures and flue differential pressure of each flue of the vacuum heat pipe low-temperature economizer, the water inlet temperature, water outlet temperature, water inlet pipe flow, return pipe flow of the vacuum heat pipe low-temperature economizer, the load of the boiler system, the flue gas volume and the coal consumption.

[0017] As a preferred embodiment, the steps for calculating the heat exchange power of the vacuum heat pipe low-temperature economizer according to the principle of light-heat balance are specifically as follows:

[0018] The heat exchange power of the vacuum heat pipe low-temperature economizer is the heat Q that the cooling water recovers from the high-temperature flue gas heat into the water. The specific calculation formula is as follows:

[0019] Q=C Ps ×m s ×Δt2

[0020] Where C Ps is the specific heat of water in the vacuum heat pipe low-temperature economizer at the qualitative water temperature, m s is the cooling water volume passing through the vacuum heat pipe low-temperature economizer, Δt2 is the average water temperature in the heat exchanger of the vacuum heat pipe low-temperature economizer;

[0021] As a preferred embodiment, the steps of calculating the increase in the equivalent heat drop of fresh steam of the low-pressure heater heating system using the heat exchange power of the vacuum heat pipe low-temperature economizer according to the thermodynamic principles and the equivalent heat drop principle are specifically as follows:

[0022] ΔH=q d η jp

[0023] Where ΔH is the increase in the equivalent heat drop of new steam in the low-pressure heating system; q d is the unit working fluid load of the low-pressure heater; η jp is the average steam extraction efficiency of heat utilization in the low-pressure heating system;

[0024] As a preferred embodiment, the unit working fluid load q of the low-pressure heater is d The specific calculation formula is as follows:

[0025]

[0026] Where, Q is the heat recovered by cooling water from high-temperature flue gas; D is the new steam consumption; a d is the unit new steam share; td is the outlet water enthalpy of the vacuum heat pipe; t w(m-1) is the outlet enthalpy of the (m-1)th stage of the low-pressure heater; τ j is the unit feed water enthalpy rise in the j-th stage low-pressure heater.

[0027] As a preferred embodiment, the average steam extraction efficiency η of the heat utilization of the low-pressure heating system is jp The specific calculation formula is as follows:

[0028]

[0029] In the formula, η m is the steam extraction efficiency of the mth stage low-pressure heater.

[0030] As a preferred embodiment, the optimal value range of the fresh steam equivalent heat drop increase and the cooling water volume based on the low-pressure heater heating system is obtained by recursively solving the optimal real-time value of the cooling water volume using a divide-and-conquer algorithm. Specifically, the steps are as follows:

[0031] According to the calculation formula of the equivalent heat drop increase ΔH of the low-pressure heater, the equivalent heat drop increase ΔH of the new steam of the low-pressure heater system and the cooling water volume m are obtained. s The functional relationship is as follows:

[0032]

[0033] Use the divide-and-conquer algorithm to recursively solve the function ΔH=g(m s ), the specific formula is as follows:

[0034]

[0035] The maximum value point P(m sg , ΔH max ) corresponds to m sg is the optimal cooling water volume at the current moment, ΔH max It is the maximum value of the increase in the equivalent heat drop of new steam in the low-pressure heater system at the current moment.

[0036] As a preferred embodiment, the cooling water flow constraint for the vacuum heat pipe low-temperature economizer based on the dust removal efficiency of the dust collector, the low-temperature corrosion rate of the vacuum heat pipe, and the hydrophobic pressure threshold of the low-temperature heater, and the steps of determining the cooling water flow value range that meets the dust removal efficiency, low-temperature corrosion rate, and hydrophobic pressure threshold are specifically as follows:

[0037] Determine the range of cooling water required when the dust removal efficiency of the dust collector is set to the threshold value: Use the neural network to build the dust removal efficiency η esp and the dust collector inlet flue gas temperature T espIn Relational model: f(T espIn )=η esp When the dust collector takes the minimum dust removal efficiency, the dust collector inlet smoke temperature reaches the maximum value. At this time, the amount of cooling water required for the dust collector inlet smoke temperature must be greater than m s1 , that is, the cooling water volume based on the dust removal efficiency threshold is in the range of U1=[ms1 , m smax ], where m smax The maximum amount of cooling water that can pass through the vacuum heat pipe low-temperature economizer;

[0038] The range of cooling water required to determine the threshold value of the low-temperature corrosion rate of the vacuum tube is as follows: the flue gas temperature T at the dust collector inlet espIn Need to be greater than the flue gas dew point temperature T dn , according to the flue gas dew point temperature, determine the minimum value of the dust collector inlet flue gas temperature, at this time the dust collector inlet flue gas temperature required cooling water volume should be less than m s2 , that is, the cooling water volume based on the dust removal efficiency threshold value range is U2=[0,m s2 ];

[0039] The range of cooling water required when the hydrophobic pressure of the low-pressure heater is set to the threshold value is as follows: According to the minimum temperature of the cooling water outlet of the vacuum heat pipe, the cooling water required at this time must be greater than m s3 , that is, the cooling water volume based on the hydrophobic pressure threshold value range is U3=[m s3 , m smax ], where m smax It is the maximum amount of cooling water that can pass through the vacuum heat pipe low-temperature economizer.

[0040] As a preferred embodiment, the step of simultaneously satisfying the cooling water flow range of the three thresholds as the optimal value range is specifically as follows:

[0041] When the dust removal efficiency of the dust collector and the low-temperature corrosion rate and hydrophobic pressure of the vacuum heat pipe meet the threshold conditions, the corresponding cooling water volume range is U1=[m s1 , m smax ]、U2=[0,m s2 ]、U3=[m s3 , m smax ];

[0042] When U1, U2 and U3 are intersected, the optimal range of cooling water volume U is obtained. sp :

[0043] As a preferred embodiment, after adding weight parameters in the step of setting weight parameters to ensure that the final value range of the cooling water volume is not an empty set, when the dust removal efficiency, low-temperature corrosion rate, and hydrophobic pressure take thresholds, the corresponding cooling water volume value range is:

[0044] U′1=[m s1 (1+ω a ), m smax ]

[0045] U′2=[0,m s2(1-ω b )]

[0046] U′3=[m s3 (1+ω c ),m smax ]

[0047] Where, ω a 、ω b and ω c are all weight parameters.

[0048] The present invention has the following beneficial effects:

[0049] 1. The present invention studies thermodynamic analysis, equivalent heat drop theory and data modeling methods, combines the operating parameters of the vacuum heat pipe low-temperature economizer, and calculates the equivalent heat drop increase of the low-pressure heater to evaluate the thermal efficiency of the vacuum heat pipe low-temperature economizer in real time.

[0050] 2. The present invention analyzes the influence of parameters such as the low-temperature economizer gas outlet flue gas temperature and outlet water temperature of the vacuum heat pipe on the dust removal efficiency, low-temperature corrosion rate, and hydrophobic pressure, and jointly limits the value range of the vacuum heat pipe cooling water volume.

[0051] 3. This invention dynamically adjusts the cooling water flow range using weight parameters to ensure that the cooling water flow range is not empty. Real-time data monitoring of dust removal efficiency, low-temperature corrosion rate, and hydrophobic pressure indicators reveals significant abnormal risks. The weight parameters are automatically adjusted to optimize the cooling water flow range, while also preventing abnormalities in the operating conditions of the dust collector, vacuum heat pipe, and low-pressure heater.

[0052] 4. This proposal determines, within a specified cooling water flow range, the cooling water flow that maximizes the increase in the equivalent heat drop of live steam in the low-pressure heater system. This flow is the optimal cooling water flow. The relationship between the valve and the water flow is then used to control the opening of the electric regulating valve in the water inlet pipe, achieving automatic control. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 is a flow chart of the steps of the present invention;

[0054] Figure 2 This is the structure and working principle diagram of the vacuum heat pipe low-temperature economizer;

[0055] Figure 3 This is a flowchart of the actual operation of the vacuum heat pipe low-temperature economizer of the embodiment of the invention; DETAILED DESCRIPTION

[0056] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0057] It should be understood that the step numbers used herein are only for convenience of description and are not intended to limit the order in which the steps are to be executed.

[0058] It should be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an" and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0059] The terms “include” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0060] The term "and / or" refers to and includes any and all possible combinations of one or more of the associated listed items.

[0061] Example 1:

[0062] See also Figure 1 , an intelligent water quantity control method for a vacuum heat pipe low-temperature economizer, specifically comprising the following steps:

[0063] Step S100: obtaining the operating parameters of the vacuum heat pipe low-temperature economizer through the communication interfaces of the vacuum heat pipe low-temperature economizer;

[0064] In this embodiment, the structure of the vacuum heat pipe low temperature economizer is as follows: Figure 2 As shown, the collected operating parameters include the flue gas inlet and outlet temperatures and flue pressure differential of each flue of the vacuum heat pipe low-temperature economizer, the water inlet temperature, water outlet temperature, water inlet pipe flow, return pipe flow of the vacuum heat pipe low-temperature economizer, the load of the boiler system, the flue gas volume and the coal consumption.

[0065] Step S200: Calculating the heat exchange power of the vacuum heat pipe low-temperature economizer according to the principle of light-heat balance;

[0066] In this embodiment, the heat exchange power of the vacuum heat pipe low-temperature economizer is the heat Q that the cooling water recovers from the high-temperature flue gas heat into the water. The specific calculation formula is as follows:

[0067] Q=CPs ×m s ×Δt2

[0068] Where C Ps is the specific heat of water in the vacuum heat pipe low-temperature economizer at the qualitative water temperature, m s is the cooling water volume passing through the vacuum heat pipe low-temperature economizer, Δt2 is the average water temperature in the heat exchanger of the vacuum heat pipe low-temperature economizer;

[0069] Among them, the water specific heat C of the vacuum heat pipe low temperature economizer at the qualitative water temperature is Ps The specific calculation formula is as follows:

[0070] c Ps =z(t s )

[0071] Where, t s To determine the water temperature, the specific calculation formula is as follows:

[0072]

[0073] Wherein, t3 is the cooling water inlet temperature of the vacuum heat pipe low-temperature economizer, and t4 is the cooling water outlet temperature of the vacuum heat pipe low-temperature economizer.

[0074] Step S300: Calculate the increase in the equivalent heat drop of fresh steam in the low-pressure heater heating system based on the heat exchange power of the vacuum heat pipe low-temperature economizer according to thermodynamic principles and the equivalent heat drop principle, and use the value of the increase in the equivalent heat drop of fresh steam as an evaluation criterion for the economic benefit of flue gas waste heat utilization;

[0075] In this embodiment, based on thermodynamic theory, the specific calculation formula for the increase in the equivalent heat drop ΔH of the fresh steam of the low-pressure heater system is as follows:

[0076] ΔH=q d η jp

[0077] Where ΔH is the increase in the equivalent heat drop of new steam in the low-pressure heating system; q d is the unit working fluid load of the low-pressure heater; η jp is the average steam extraction efficiency of heat utilization in the low-pressure heating system;

[0078] Among them, the unit working fluid load q of the low-pressure heater is d The calculation formula is as follows:

[0079]

[0080] Where, Q is the heat recovered by cooling water from high-temperature flue gas; D is the new steam consumption; a d is the unit new steam share; t dis the outlet water enthalpy of the vacuum heat pipe; t w(m-1) is the outlet enthalpy of the (m-1)th stage of the low-pressure heater; is the unit feed water enthalpy rise in the j-th stage low-pressure heater.

[0081] The specific calculation formula for the average steam extraction efficiency of heat utilization in the low-pressure heating system is as follows:

[0082]

[0083] Where η m is the steam extraction efficiency of the mth stage low-pressure heater, and its specific calculation formula is:

[0084]

[0085] Where h m is the extraction enthalpy of the mth stage of the low-pressure heater, is the equivalent enthalpy drop of the extraction steam of the m+1th stage of the low-pressure heater, Γ m+1 is the hydrophobic heat release of the m+1th stage of the low-pressure heater, h m is the turbine drain enthalpy of the mth stage of the low-pressure heater.

[0086] When m is the last stage low pressure heater, Where h c is the turbine exhaust enthalpy of the low-pressure heater.

[0087] By analyzing the above formula, we can know that increasing the cooling water volume will increase the heat load q of the low pressure heater. d , thereby improving the economic effect; but as the cooling water volume m s The outlet water enthalpy of the vacuum heat pipe heat exchanger t d It will reduce and change the energy level and structure of the multi-stage utilization of waste heat of the low-pressure heater, so that the average extraction efficiency η of the heat utilization of the low-pressure heating system jp In summary, there is an optimal cooling water volume m for vacuum heat pipes. sp , making ΔH the largest, at this time the economic benefit of flue gas waste heat utilization is the highest.

[0088] Step S400: Based on the dust removal efficiency of the dust collector, the low-temperature corrosion rate of the vacuum heat pipe, and the drain pressure threshold of the low-temperature heater, the cooling water flow constraint for the vacuum heat pipe low-temperature economizer is determined. The cooling water flow range that satisfies the dust removal efficiency, low-temperature corrosion rate, and drain pressure threshold is determined. The cooling water flow range that satisfies all three thresholds is the optimal range.

[0089] In this embodiment, the cooling water flow range is determined by analyzing the influence of parameters such as the low-temperature economizer gas outlet temperature and the outlet water temperature on the dust removal efficiency, low-temperature corrosion rate, and hydrophobic pressure of the vacuum heat pipe:

[0090] For dust removal efficiency: Build a model of the relationship between dust removal efficiency and dust collector inlet smoke temperature. Based on historical data, use the neural network modeling method to build the dust removal efficiency η esp and the dust collector inlet flue gas temperature T espIn Relational model f(T espIn )=η esp Through this relationship model and process mechanism, it can be known that the dust collector inlet flue gas temperature T espIn and dust removal efficiency η esp Inversely proportional relationship, that is, T espIn The larger the η esp Therefore, the maximum value T of the dust collector inlet flue gas temperature can be determined by using the relational model and real-time calculation of the required minimum dust removal efficiency. espIn_max The corresponding cooling water volume must be greater than m s1 °

[0091] For low temperature corrosion: Based on the thermal properties of the equipment and the reasoning of low temperature corrosion, when the metal wall temperature is lower than the flue gas dew point temperature, metal low temperature corrosion will occur quickly, affecting the service life of the equipment and the safety of the unit operation. Since the metal wall will be heated by the dust collector inlet flue gas, its temperature is closely related to the dust collector inlet flue gas temperature T espIn Therefore, the dust collector inlet flue gas temperature T espIn There are certain requirements. T espIn Greater than the flue gas dew point temperature T dn Add a certain incremental temperature ΔT l , which can reduce the low-temperature corrosion rate to an acceptable range. The minimum value Te of the dust collector inlet flue gas temperature can be determined based on the flue gas dew point temperature. spIn_min The corresponding cooling water volume should be less than m s2 .

[0092] Regarding drain pressure: When the cooling water of the vacuum heat pipe flows into the pipe at a higher temperature, it will cause the liquid in the low-pressure heater and condenser pipe to vaporize easily, causing the condenser pressure to change, and ultimately leading to drain difficulties. The minimum value T of the outlet water temperature of the vacuum heat pipe cooling water can be determined based on the change of the drain pressure of the condensate pump. gghwout_min The corresponding cooling water volume must be greater than m s3 .

[0093] In summary, the cooling water volume set U1=[m s1 , m smax ]、set U2=[0,m s2 ]、set U3=[ms3 , m smax ]The intersection of three sets U sp , that is, m sp ∈U sp , where m smax The maximum amount of cooling water that can pass through the heat exchanger.

[0094] Step S500: ensuring that the final value range of the cooling water volume is not an empty set by setting weight parameters, and automatically adjusting the value range of the cooling water volume to keep it within the optimal value range when the values ​​of the dust removal efficiency, low-temperature corrosion rate, and hydrophobic pressure reach critical values;

[0095] In this embodiment, by setting the weight parameter to ensure that the final value range of the cooling water volume is not an empty set, after adding the weight parameter in the step of adding the weight parameter, when the dust removal efficiency, low-temperature corrosion rate, and hydrophobic pressure take thresholds, the corresponding cooling water volume value range is:

[0096] U′1=[m s1 (1+ω a ), m smax ]

[0097] U′2=[0,m s2 (1-ω b )]

[0098] U′3=[m s3 (1+ω c ), m smax ]

[0099] Where, ω a 、ω b and ω c are all weight parameters.

[0100] when The basic weight parameter ω is allocated based on the degree of attention paid to dust removal efficiency, low-temperature corrosion rate, and hydrophobic pressure. a 、ω b 、ω c , and then adjust the value range of U1, U2, and U3 through the weight parameters.

[0101] At the same time, by real-time monitoring of dust removal efficiency, low-temperature corrosion rate and low-pressure heater drain pressure changes, when a significant risk (dust removal efficiency is too low, low-temperature corrosion is too fast or low-pressure heater drain pressure is difficult) is detected, the weight parameter ω is automatically adjusted. a 、ω b 、ω c , making U sp The value is closer to its limit range.

[0102] Step S600: Based on the optimal value range of the fresh steam equivalent heat drop increase and the cooling water volume of the low-pressure heater heating system, a divide-and-conquer algorithm is used to recursively solve and obtain the optimal real-time value of the cooling water volume;

[0103] In this embodiment, the specific steps of using the divide-and-conquer algorithm to recursively solve and obtain the optimal real-time value of the cooling water volume are as follows:

[0104]

[0105] That is, ΔH=g(m s ) in the domain: m s ∈U sp The maximum point P(m sg , ΔH max ), the obtained m sg is the optimal cooling water volume m at the current moment sp , ΔH max It is the maximum value of the increase in the equivalent heat drop of the new steam in the low-pressure heater heating system at the current moment.

[0106] Step S700: fitting a function of the cooling water volume and the opening of the electric regulating valve of the water inlet pipe according to historical data, and dynamically adjusting the opening of the electric regulating valve of the water inlet pipe based on the optimal real-time value of the cooling water volume.

[0107] In this embodiment, the cooling water volume m is fitted by the historical data fitting method. s Relationship with water valve opening k: y(k)=m s Based on the desired optimal cooling water volume m sp Calculate the water outlet valve opening k in real time to achieve automatic control.

[0108] Finally, based on the above steps, the working process of the vacuum heat pipe low temperature economizer in actual operation is as follows: Figure 3 shown.

[0109] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An intelligent water control method for a vacuum heat pipe low-temperature economizer, characterized in that: The specific steps include: Obtain the operating parameters of the vacuum heat pipe low-temperature economizer through each communication interface of the vacuum heat pipe low-temperature economizer; Calculate the heat transfer power of vacuum heat pipe low temperature economizer based on the principle of light and heat balance; Based on the principles of thermodynamics and equivalent heat drop, the heat exchange power of the vacuum heat pipe low-temperature economizer is used to calculate the increase in the equivalent heat drop of fresh steam in the low-pressure heater heating system. This value is used as the evaluation standard for the economic benefits of flue gas waste heat utilization. Based on the dust removal efficiency of the dust collector, the low-temperature corrosion rate of the vacuum heat pipe, and the low-temperature heater's drain pressure threshold, the cooling water flow constraints for the vacuum heat pipe low-temperature economizer are determined. The cooling water flow range that meets the dust removal efficiency, low-temperature corrosion rate, and drain pressure threshold is determined. The cooling water flow range that meets all three thresholds is the optimal range. By setting weight parameters, the final value range of the cooling water volume is ensured to be non-empty, and when the values ​​of dust removal efficiency, low-temperature corrosion rate, and hydrophobic pressure reach critical values, the value range of the cooling water volume is automatically adjusted to keep it within the optimal value range; Based on the optimal range of the equivalent heat drop increase of fresh steam and the cooling water volume of the low-pressure heater heating system, a divide-and-conquer algorithm is used to recursively solve the optimal real-time value of the cooling water volume. The function of cooling water volume and the opening of the electric regulating valve of the water inlet pipe is fitted according to historical data, and the opening of the electric regulating valve of the water inlet pipe is dynamically adjusted based on the optimal real-time value of cooling water volume.

2. The intelligent water control method for a vacuum heat pipe low-temperature economizer according to claim 1, characterized in that: The operating parameters include the flue gas inlet and outlet flue gas temperatures and flue pressure differential of each flue of the vacuum heat pipe low-temperature economizer, the water inlet temperature, water outlet temperature, water inlet pipe flow, return pipe flow of the vacuum heat pipe low-temperature economizer, the load of the boiler system, the flue gas volume and the coal consumption.

3. The intelligent water control method for a vacuum heat pipe low-temperature economizer according to claim 1, characterized in that: The specific steps for calculating the heat exchange power of the vacuum heat pipe low-temperature economizer based on the principle of light-heat balance are as follows: The heat exchange power of the vacuum heat pipe low temperature economizer is the heat that the cooling water recovers from the high temperature flue gas into the water. , the specific calculation formula is as follows: Where, is the specific heat of water in the vacuum heat pipe low-temperature economizer at the qualitative water temperature, is the amount of cooling water passing through the vacuum heat pipe low-temperature economizer, is the average water temperature in the heat exchanger of the vacuum heat pipe low-temperature economizer.

4. The intelligent water control method for a vacuum heat pipe low-temperature economizer according to claim 1, characterized in that: The steps for calculating the increase in the equivalent heat drop of fresh steam from the low-pressure heater heating system using the heat exchange power of the vacuum heat pipe low-temperature economizer according to the thermodynamic principles and the equivalent heat drop principle are as follows: Where, The increase in the equivalent heat drop of new steam in the low-pressure heating system; is the unit working fluid load of the low-pressure heater; is the average steam extraction efficiency of heat utilization in the low-pressure heating system.

5. The intelligent water control method for a vacuum heat pipe low-temperature economizer according to claim 4, characterized in that: Unit working fluid load of the low-pressure heater The specific calculation formula is as follows: Where, Recover the heat of high-temperature flue gas into water for cooling water; is the new steam consumption; is the unit new steam share; is the outlet water enthalpy of the vacuum heat pipe; For low pressure heater The outlet enthalpy of the stage; is the unit feed water enthalpy rise in the j-th stage low-pressure heater.

6. The intelligent water control method for a vacuum heat pipe low-temperature economizer according to claim 4, characterized in that: The average steam extraction efficiency of heat utilization of the low-pressure heating system The specific calculation formula is as follows: In the formula, is the steam extraction efficiency of the mth stage low-pressure heater.

7. The intelligent water control method for a vacuum heat pipe low-temperature economizer according to claim 4, characterized in that: The optimal range of the equivalent heat drop increase of the fresh steam and the cooling water volume based on the low-pressure heater heating system is obtained by recursively solving the optimal real-time value of the cooling water volume using a divide-and-conquer algorithm. Specifically, the steps are as follows: Increase according to the equivalent heat drop of the low-pressure heater The calculation formula is used to obtain the increase in the equivalent heat drop of new steam in the low-pressure heater system. and cooling water volume The functional relationship is as follows: Recursively solve a function using a divide-and-conquer algorithm The maximum value of is as follows: The maximum value point obtained Corresponding is the optimal cooling water volume at the current moment, It is the maximum value of the increase in the equivalent heat drop of new steam in the low-pressure heater system at the current moment.

8. The intelligent water control method for a vacuum heat pipe low-temperature economizer according to claim 1, characterized in that: The cooling water quantity constraint of the vacuum heat pipe low-temperature economizer based on the dust removal efficiency of the dust collector, the low-temperature corrosion rate of the vacuum heat pipe, and the hydrophobic pressure threshold of the low-temperature heater is determined, and the steps of determining the cooling water quantity value range that meets the dust removal efficiency, the low-temperature corrosion rate, and the hydrophobic pressure threshold are specifically as follows: Determine the range of cooling water required when the dust removal efficiency of the dust collector is set to the threshold value: Use the neural network to build a dust removal efficiency and dust collector inlet flue gas temperature Relational Model: When the dust collector takes the minimum dust removal efficiency, the dust collector inlet smoke temperature reaches the maximum value. At this time, the amount of cooling water required for the dust collector inlet smoke temperature must be greater than , that is, the cooling water volume based on the dust removal efficiency threshold value range is ,in, The maximum amount of cooling water that can pass through the vacuum heat pipe low-temperature economizer; The range of cooling water required to determine the threshold value of the low-temperature corrosion rate of the vacuum tube is as follows: the flue gas temperature at the dust collector inlet Need to be greater than the flue gas dew point temperature , according to the flue gas dew point temperature, determine the minimum value of the dust collector inlet flue gas temperature, at this time the amount of cooling water required for the dust collector inlet flue gas temperature must be less than , that is, the cooling water volume based on the dust removal efficiency threshold value range is ; The range of cooling water required when the low-pressure heater's drain pressure reaches the threshold is as follows: Based on the minimum temperature of the vacuum heat pipe cooling water outlet, the required cooling water volume must be greater than , that is, the cooling water volume based on the hydrophobic pressure threshold value range is ,in, It is the maximum amount of cooling water that can pass through the vacuum heat pipe low-temperature economizer.

9. The intelligent water control method for a vacuum heat pipe low-temperature economizer according to claim 8, characterized in that: The step of determining that the cooling water volume range that satisfies the three thresholds at the same time is the optimal value range is specifically as follows: When the dust removal efficiency of the dust collector and the low-temperature corrosion rate and hydrophobic pressure of the vacuum heat pipe meet the threshold conditions, the corresponding cooling water volume range is divided into 、 、 ; right 、 and When taking the intersection, the optimal range of cooling water volume is obtained .

10. The intelligent water control method for a vacuum heat pipe low-temperature economizer according to claim 8, characterized in that: After adding the weight parameter in the step of setting the weight parameter to ensure that the final value range of the cooling water volume is not an empty set, when the dust removal efficiency, low-temperature corrosion rate, and hydrophobic pressure take thresholds, the corresponding cooling water volume value range is: Where, 、 and are all weight parameters.

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