A heat supply efficiency optimization control method of a combined heat and power unit

Abstract

The application discloses a heat supply efficiency optimization control method of a combined heat and power unit, and belongs to the field of optimization control of combined heat and power units.The application obtains real-time operation parameters of multiple candidate backwater injection stages, and determines an effective injection stage set according to the real-time operation parameters, so that the distribution object of the backwater heat of the heat supply is no longer limited to fixed low-pressure heaters or fixed pipe stages, but can be dynamically screened in combination with the thermal state, heat receiving capacity and adjustment condition of each stage under the current working condition, thereby avoiding injecting backwater heat into a stage with a temperature close to the upper limit, a mismatched thermal grade or insufficient valve adjustment capacity, and improving the safety and working condition adaptability of the backwater heat distribution.

Description

Technical Field

[0001] This invention relates to the field of optimized control of cogeneration units, specifically to a method for optimizing the heating efficiency of cogeneration units. Background Technology

[0002] Cogeneration units can simultaneously output electrical and thermal energy. During the heating season, they typically use turbine-extracted steam to heat the return water of the heating network to meet external heating demands. After the extracted steam releases heat and condenses in the heating network heaters, or after heat exchange in the return water, the heat is transferred to the unit's condensate system. Since the temperature of the return water or recovered heat is usually higher than the water temperature in some sections of the condensate pipes, if this heat can be rationally distributed to different locations in the regenerative system according to its thermal grade, the consumption of some extracted steam can be reduced, the degree of degradation of high-grade steam can be decreased, and the overall energy utilization efficiency of the unit can be improved.

[0003] In existing combined heat and power (CHP) units, the connection methods for heating return water or related recovered heat often rely on fixed pipelines, fixed stages, or manual experience rules. For example, heating return water is connected to a pre-set condensate header, fixed pipe sections before and after the low-pressure heaters, or simply switched based on single parameters such as return water temperature and unit load. Although the control logic of this type of method is relatively simple, it is essentially still a static or semi-static distribution method, making it difficult to determine the optimal injection location and distribution ratio of heating return water heat in real time based on the real-time temperature, pressure, steam extraction rate, terminal temperature difference, valve regulation capacity, and changes in heating load of each stage of low-pressure heaters.

[0004] In actual operation, different low-pressure heater stages are not independent of each other. Injecting heat from the return water into a stage not only changes the condensate outlet temperature, terminal temperature difference, and extraction steam rate of that stage, but may also affect the temperature distribution and extraction steam demand of subsequent stages through the condensate series system. Especially when the unit's electrical load, heating load, return water temperature, or return water flow rate fluctuates, the heat acceptance capacity and unit heat utilization benefit of each candidate injection stage will change with the operating conditions. If allocation is still based on fixed stages or a single indicator, problems such as insufficient heat acceptance capacity in local stages, insufficient valve adjustment margin, mismatched thermal grades, or failure to consider the mutual influence between multiple stages can easily occur, leading to insufficient utilization of the return water heat.

[0005] Furthermore, existing control methods typically determine allocation strategies based solely on theoretical calculations or preset models, lacking online identification of actual operational responses. Since the heat exchange performance of low-pressure heaters, pipeline resistance, valve operating characteristics, extraction steam status, and sensor measurements all change over time, deviations easily arise between theoretical models and actual operating conditions. If the unit heat gain relationship of each injection stage cannot be corrected during operation through disturbance testing, response acquisition, and model updates, it is difficult to guarantee the selection of the optimal or near-optimal heating and return water allocation scheme throughout long-term operation.

[0006] Meanwhile, existing heating return water distribution control focuses primarily on the selection of individual injection points, lacking the identification and utilization of the thermodynamic coupling relationships between multiple candidate injection stages. When multiple stages participate in the heating return water heat distribution simultaneously, failure to consider the cross-influence between stages may lead to problems such as simultaneous temperature increases in some stages, abnormal local end-to-end differences, reduced steam extraction substitution effects, or frequent valve actuations, affecting system stability and energy-saving performance. Therefore, relying solely on single-stage optimization or simple sorting allocation is insufficient to meet the requirements of multi-stage collaborative optimization under complex operating conditions.

[0007] Furthermore, in scenarios where heating loads continuously change, the distribution of heat in the heating return water not only needs to consider the current heat acceptance capacity but also the heating load deviation, heating extraction steam consumption, equivalent power supply coal consumption, total system entropy production, and valve actuation range within the forecast period. Existing technologies lack control methods that integrate real-time identification results, heat acceptance constraints, stage coupling relationships, and heating load demands into a rolling optimization model, making it difficult to achieve dynamic optimal distribution of heating return water heat among multiple injection stages while ensuring heating stability and equipment safety.

[0008] Therefore, existing technologies have at least the following problems: the location and allocation ratio of heat injection into the heating return water mainly rely on fixed stages or empirical rules, making it impossible to dynamically select effective injection stages based on the real-time thermodynamic and regulatory states of each candidate injection stage; there is a lack of means to identify multiple injection stages online through coded perturbations, making it difficult to obtain the unit heat gain relationship under real operating conditions; the thermodynamic coupling effect between different injection stages is not fully considered, resulting in insufficient accuracy of multi-stage collaborative allocation; there is a lack of a rolling optimization allocation mechanism that combines heat acceptance constraints, heating load demand, and predicted response, and there is also a lack of closed-loop control capability to update the model online based on actual operating response, ultimately resulting in low heating return water heat utilization efficiency, unstable heating steam extraction substitution effect, and insufficient adaptive optimization capability under complex operating conditions. Summary of the Invention

[0009] The purpose of this invention is to overcome the problems in the prior art, where the distribution of heat in the heating return water largely depends on fixed stages or empirical rules, lacking online identification and closed-loop optimization of the actual benefits of each candidate injection stage and the coupling relationship between stages, resulting in low return water heat utilization efficiency and unstable heating steam extraction substitution effect. This invention provides a heating efficiency optimization control method for cogeneration units.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for optimizing and controlling the heating efficiency of a combined heat and power (CHP) unit, comprising the following steps: The real-time operating parameters of different candidate return water injection stages in the regenerative system of a cogeneration unit are obtained, and the effective injection stage set is determined based on the real-time operating parameters. Within the effective injection stage set, the heating return water heat is divided into basic distribution heat and identified disturbance heat. The identified disturbance heat is superimposed and distributed to at least two effective injection stages according to the preset coding disturbance method. Collect operational response data of each effective injection stage under the influence of identified heat disturbance, and identify the unit heat gain relationship of each effective injection stage and the thermodynamic coupling relationship between different effective injection stages online based on the operational response data; Based on the unit heat gain relationship, thermodynamic coupling relationship, heat acceptance constraints of each effective injection stage, and heating load demand, solve the optimal distribution scheme of heating return water heat among each effective injection stage within the current control cycle. Generate the return water injection regulating valve opening command corresponding to each effective injection stage according to the optimal allocation scheme, and execute the heating return water heat allocation according to the return water injection regulating valve opening command. After the heat distribution of the heating return water is implemented, the actual operating response is compared with the predicted operating response, and the unit heat gain relationship and thermodynamic coupling relationship are updated based on the comparison results.

[0011] A further improvement of the present invention is that the candidate return water injection stage includes at least two of the following: the condensate side inlet of the low-pressure heater, the condensate side outlet of the low-pressure heater, the condensate connection pipe section between adjacent low-pressure heaters, the condensate pump outlet pipe section, and the condensate pipe section before the deaerator inlet. Real-time operating parameters include condensate inlet temperature, condensate outlet temperature, condensate inlet pressure, condensate outlet pressure, condensate flow rate, extraction steam pressure, extraction steam temperature, extraction steam volume, heating return water temperature, heating return water flow rate, unit electrical load, heating load, low-pressure heater terminal differential pressure, condensate temperature, and parameters in the current opening of the return water injection regulating valve.

[0012] A further improvement of this invention lies in the following method for determining the effective injection stage set based on real-time operating parameters: The heat acceptance capacity of the candidate return water injection stage is calculated based on the current condensate outlet temperature, the maximum allowable condensate outlet temperature, the condensate flow rate, and the condensate specific heat capacity. The thermal quality matching degree of the candidate return water injection stage is calculated based on the temperature difference between the heating return water temperature and the condensate temperature of the candidate return water injection stage, the extraction steam saturation temperature of the corresponding stage, and the terminal difference of the low-pressure heater. The availability of regulation for each candidate return water injection stage is calculated based on the remaining opening, regulation sensitivity, historical tracking error, and fault status of the return water injection regulating valve. Candidate return water injection stages that meet preset conditions in terms of heat acceptance capacity, thermal grade matching degree, and regulation availability are identified as effective injection stages and are used as the set of effective injection stages.

[0013] A further improvement of this invention lies in the following specific method for dividing the heat return water into basic distribution heat and identified disturbance heat: A portion of the total heat from the heating return water is used as the base heat allocation and distributed to the corresponding effective injection stage according to the allocation scheme determined in the previous control cycle. The remaining portion of the total heat of the heating return water is used as the identified disturbance heat, which is 1% to 10% of the total heat of the heating return water, and the sum of the base-allocated heat and the identified disturbance heat of any effective injection stage does not exceed the heat acceptance capacity of that effective injection stage.

[0014] A further improvement of the present invention is that the specific method for superimposing and distributing the identified perturbation heat to at least two effective injection stages according to a preset coding perturbation method is as follows: Configure coded perturbation sequences for different effective injection stages; Within the same identification period, the identification perturbation heat is superimposed and distributed to each effective injection stage according to the corresponding coded perturbation sequence. The correlation coefficient between the coded perturbation sequences corresponding to different effective injection stages is less than the preset correlation threshold, so that multiple effective injection stages can apply identification perturbation heat synchronously within the same identification period. The independent response of each effective injection stage is obtained by decoding and separation. The coded perturbation sequence is a pseudo-random binary coded sequence, a Hadamard coded sequence, or a zero-mean orthogonal coded sequence.

[0015] A further improvement of this invention lies in the following specific method for identifying the unit heat gain relationship of each effective injection stage and the thermodynamic coupling relationship between different effective injection stages online based on operational response data: Collect partial data from each effective injection stage, including changes in condensate inlet temperature, condensate outlet temperature, pressure, steam extraction rate, low-pressure heater terminal temperature difference, heating load, unit heat consumption, and the actual opening change of the corresponding return water injection regulating valve. The collected operational response data is subjected to time delay compensation, steady-state component removal, and filtering to obtain net response data; Based on the coded perturbation sequence and net response data, the unit heat gain coefficient of each effective injection stage is calculated, and the thermal coupling coefficient between different effective injection stages is also calculated.

[0016] A further improvement of the present invention is that the unit heat gain coefficient is calculated based on at least two of the following: the change in total entropy production of the system caused by the injection of unit heat return water into the corresponding effective injection stage, the reduction in steam extraction for heating, the change in equivalent coal consumption for power generation, and the change in heating load deviation. Thermo-coupling coefficient is used to characterize the degree of influence of the change in the heating return water injection rate of one effective injection stage on the changes in condensate outlet temperature, extraction steam rate, terminal temperature difference, or entropy production of another effective injection stage. The segment coupling matrix is ​​composed of the thermo-mechanical coupling coefficients of each effective injection segment. The diagonal elements in the segment coupling matrix represent the self-response relationship of the corresponding effective injection segment, and the off-diagonal elements represent the cross-influence relationship between different effective injection segments.

[0017] A further improvement of this invention lies in the following method for determining the optimal allocation scheme of heating return water heat among the effective injection stages within the current control cycle, based on the unit heat gain relationship, thermodynamic coupling relationship, heat acceptance constraints of each effective injection stage, and heating load demand: A rolling optimization model is established. The objective function of the rolling optimization model includes at least two of the following: minimizing the total entropy production of the system, minimizing the steam consumption for heating extraction, minimizing the equivalent coal consumption for power generation, minimizing the heating load deviation, and penalizing the change in the opening of the return water injection regulating valve. The constraints of the rolling optimization model include heat balance constraints, heat acceptance capacity constraints, condensate outlet temperature constraints, valve opening constraints, and heating load deviation constraints. Based on the unit heat gain relationship, thermodynamic coupling relationship, heat acceptance constraints of each effective injection stage, and heating load demand, the distributed heat of each effective injection stage in the current control cycle can be obtained under the condition that the constraints are met.

[0018] A further improvement of this invention lies in the following method: after the heat distribution of the heating return water is executed, the actual operating response is compared with the predicted operating response, and the unit heat gain relationship and thermodynamic coupling relationship are updated based on the comparison results: Acquire partial data from the actual condensate outlet temperature, actual steam extraction rate, actual heating load, actual equivalent coal consumption for power generation, and actual valve opening within the current control cycle; Compare the actual operating response with the predicted operating response corresponding to the rolling optimization model; When the comparison deviation exceeds the preset model correction threshold, the unit heat gain relationship and thermodynamic coupling relationship are recalculated. When the condensate outlet temperature of any effective injection stage exceeds the preset safety temperature, the deviation between the actual opening and the target opening of any return water injection regulating valve exceeds the preset valve fault threshold, the fluctuation amplitude of the heating return water flow exceeds the preset flow fluctuation threshold, or the deviation between the system heat consumption response and the predicted heat consumption response exceeds the preset deviation threshold for multiple consecutive control cycles, the application of identification disturbance heat will be stopped, and the distribution mode of heating return water heat will be switched to safety retreat mode.

[0019] Secondly, the present invention provides a heating efficiency optimization control system for a combined heat and power unit, comprising: The parameter acquisition module is used to acquire real-time operating parameters of different candidate return water injection stages in the regenerative system of a cogeneration unit, and to determine the set of effective injection stages based on the real-time operating parameters. The disturbance distribution module is used to divide the heating return water heat into basic distribution heat and identified disturbance heat within the effective injection stage set, and to distribute the identified disturbance heat to at least two effective injection stages according to a preset coded disturbance method. The response identification module is used to collect the operating response data of each effective injection stage under the action of identified disturbance heat, and to identify the unit heat gain relationship of each effective injection stage and the thermodynamic coupling relationship between different effective injection stages online based on the operating response data. The optimization solution module is used to solve the optimal distribution scheme of heating return water heat among each effective injection stage within the current control cycle, based on the unit heat gain relationship, thermodynamic coupling relationship, heat acceptance constraints of each effective injection stage, and heating load demand. The valve control module is used to generate the opening command of the return water injection regulating valve corresponding to each effective injection stage according to the optimal allocation scheme, and to execute the heat distribution of the heating return water according to the opening command of the return water injection regulating valve. The model update module is used to compare the actual operating response with the predicted operating response after the heat distribution of the heating supply and return water is executed, and to update the unit heat gain relationship and thermodynamic coupling relationship based on the comparison results.

[0020] Compared with the prior art, the present invention has the following beneficial effects: This invention acquires real-time operating parameters of multiple candidate return water injection stages and determines the effective injection stage set accordingly. This allows the allocation of return water heat to no longer be limited to fixed low-pressure heaters or fixed pipe sections, but rather dynamically screens stages based on their thermal state, heat acceptance capacity, and adjustment conditions under current operating conditions. This avoids injecting return water heat into stages with temperatures close to their upper limits, mismatched heat quality, or insufficient valve adjustment capacity, thus improving the safety and adaptability of return water heat allocation. This invention divides return water heat into basic allocation heat and identified disturbance heat. While ensuring stable heating load, it uses a preset coded disturbance method to superimpose and allocate the identified disturbance heat to at least two effective injection stages, and collects corresponding operating response data. This allows for the acquisition of the true response of each injection stage without interrupting normal heating, overcoming allocation errors caused by relying solely on empirical rules or static theoretical models. This invention identifies the unit heat gain relationship of each effective injection stage and the thermodynamic coupling relationship between different effective injection stages online through operational response data. It accurately reflects the actual impact of unit return water heat injection into different stages on indicators such as total system entropy production, heating extraction steam consumption, equivalent power supply coal consumption, and heating load deviation. It also identifies the cross-effects between stages, avoiding problems such as excessively high local temperature rise, abnormal end-to-end differences, or reduced extraction steam substitution effect when multiple stages are simultaneously allocated. Based on the unit heat gain relationship, thermodynamic coupling relationship, heat acceptance constraints, and heating load demand, this invention solves for the optimal allocation scheme within the current control cycle and generates corresponding return water injection regulating valve opening commands for execution. This achieves closed-loop regulation from state acquisition, online identification, optimization solution to valve control, enabling coordinated allocation of heating return water heat among multiple effective injection stages, improving the heating extraction steam substitution effect, and reducing irreversible system losses and equivalent power supply coal consumption. This invention compares the actual operating response with the predicted operating response after allocation and execution, and updates the unit heat gain relationship and thermodynamic coupling relationship based on the comparison results. It can continuously correct model deviations caused by load fluctuations, changes in return water parameters, equipment aging, or changes in valve characteristics, so that the system can maintain a better operating state in the long term and enhance the adaptive optimization capability under complex working conditions. Attached Figure Description

[0021] Figure 1 This is a flowchart of the present invention; Figure 2 This is a system diagram of the present invention. Detailed Implementation

[0022] To further understand the content of this invention, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments are merely illustrative and not limiting of the invention.

[0023] See Figure 1A method for optimizing the heating efficiency control of a combined heat and power (CHP) unit includes the following steps: S1: Obtain the real-time operating parameters of different candidate return water injection stages in the regenerative system of the cogeneration unit, and determine the effective injection stage set based on the real-time operating parameters.

[0024] S2, within the set of effective injection stages, divide the heat of the heating return water into basic distribution heat and identified disturbance heat, and distribute the identified disturbance heat to at least two effective injection stages according to the preset coding disturbance method.

[0025] S3 collects the operational response data of each effective injection stage under the influence of identified disturbance heat, and identifies the unit heat gain relationship of each effective injection stage and the thermodynamic coupling relationship between different effective injection stages online based on the operational response data.

[0026] S4. Based on the unit heat gain relationship, thermodynamic coupling relationship, heat acceptance constraints of each effective injection stage, and heating load demand, solve the optimal distribution scheme of heating return water heat among each effective injection stage within the current control cycle.

[0027] S5 generates the return water injection regulating valve opening command corresponding to each effective injection stage according to the optimal allocation scheme, and performs the heating return water heat allocation according to the return water injection regulating valve opening command.

[0028] S6, after the heat distribution of the heating return water is executed, compares the actual operating response with the predicted operating response, and updates the unit heat gain relationship and thermodynamic coupling relationship based on the comparison results.

[0029] See Figure 2 A combined heat and power (CHP) unit heating efficiency optimization control system, comprising: The parameter acquisition module is used to acquire real-time operating parameters of different candidate return water injection stages in the regenerative system of a cogeneration unit, and to determine the set of effective injection stages based on the real-time operating parameters.

[0030] The disturbance distribution module is used to divide the heating return water heat into basic distribution heat and identified disturbance heat within the effective injection stage set, and to distribute the identified disturbance heat to at least two effective injection stages according to a preset coded disturbance method.

[0031] The response identification module is used to collect the operating response data of each effective injection stage under the influence of identified disturbance heat, and to identify the unit heat gain relationship of each effective injection stage and the thermodynamic coupling relationship between different effective injection stages online based on the operating response data.

[0032] The optimization solution module is used to solve the optimal allocation scheme of heating return water heat among each effective injection stage within the current control cycle, based on the unit heat gain relationship, thermodynamic coupling relationship, heat acceptance constraints of each effective injection stage, and heating load demand.

[0033] The valve control module is used to generate the opening command of the return water injection regulating valve corresponding to each effective injection stage according to the optimal allocation scheme, and to execute the heat distribution of the heating return water according to the opening command of the return water injection regulating valve.

[0034] The model update module is used to compare the actual operating response with the predicted operating response after the heat distribution of the heating supply and return water is executed, and to update the unit heat gain relationship and thermodynamic coupling relationship based on the comparison results.

[0035] Example 1: The cogeneration unit in this embodiment includes a steam turbine, a condenser, a condensate pump, multiple low-pressure heaters, a deaerator, a heating return water pipeline, and return water injection regulating valves respectively set for different candidate return water injection stages.

[0036] In this embodiment, the candidate return water injection stage may include the condensate side inlet of the low-pressure heater, the condensate side outlet of the low-pressure heater, the condensate connection pipe section between adjacent low-pressure heaters, the condensate pump outlet pipe section, and the condensate pipe section before the deaerator inlet. Each candidate return water injection stage is equipped with a corresponding return water injection branch and a return water injection regulating valve, so that the heating return water can be distributed to different injection stages according to control commands.

[0037] The control system acquires real-time operating parameters of each candidate return water injection stage according to a preset sampling period. The real-time operating parameters include condensate inlet temperature, condensate outlet temperature, condensate inlet pressure, condensate outlet pressure, condensate flow rate, extraction steam pressure, extraction steam temperature, extraction steam volume, heating return water temperature, heating return water flow rate, unit electrical load, heating load, low-pressure heater terminal differential pressure, condensate temperature, and the current opening degree of the return water injection regulating valve.

[0038] Based on the aforementioned real-time operating parameters, the control system calculates the heat acceptance capacity, thermal grade matching degree, and regulation availability of each candidate return water injection stage, and selects the effective injection stage set accordingly. Candidate return water injection stages that do not meet the heat acceptance conditions, temperature safety conditions, or valve regulation conditions are not included in the return water heat allocation for the current control cycle.

[0039] After obtaining the set of effective injection stages, the control system divides the heating return water heat into basic allocation heat and identified disturbance heat. The basic allocation heat is used to meet the current heating load demand, while the identified disturbance heat is used to identify the actual thermodynamic response of different injection stages without affecting heating stability. The identified disturbance heat is superimposed and distributed to at least two effective injection stages according to a preset coded disturbance method.

[0040] During the period of identifying the effect of disturbance heat, the control system collects the temperature response, pressure response, steam extraction rate response, terminal difference response, heat consumption response, and actual valve opening response of each effective injection stage, and processes the collected operating response data to obtain the net response data caused by the identified disturbance heat.

[0041] Subsequently, the control system identifies the unit heat gain relationship of each effective injection stage and the thermodynamic coupling relationship between different effective injection stages online based on the coded disturbance sequence and net response data. The unit heat gain relationship characterizes the impact of injecting a unit of heating return water heat into a certain effective injection stage on the system's total entropy production, heating steam extraction rate, equivalent power supply coal consumption, and heating load deviation. The thermodynamic coupling relationship characterizes the impact of changes in the injected heat of one effective injection stage on the thermodynamic state of other effective injection stages.

[0042] The control system further establishes a rolling optimization model based on the unit heat gain relationship, thermodynamic coupling relationship, heat acceptance constraints of each effective injection stage, and heating load demand, and solves the optimal allocation scheme of heating return water heat among each effective injection stage within the current control cycle.

[0043] After obtaining the optimal allocation scheme, the control system generates the opening command of the corresponding return water injection regulating valve based on the ratio between the allocated heat of each effective injection stage and the allocated heat of the heating return water, and sends it to each return water injection regulating valve for execution.

[0044] After execution, the control system continues to collect actual operating responses and compares them with the predicted operating responses from the rolling optimization model. When the deviation between the actual and predicted operating responses exceeds a preset model correction threshold, the control system re-identifies the unit heat gain relationship and thermodynamic coupling relationship, and re-solves for the optimal allocation scheme based on the updated identification results.

[0045] This embodiment does not fix the connection of the heating return water to a specific low-pressure heater or pipe section, but dynamically determines the optimal distribution scheme of the heating return water heat based on the real-time operating status, disturbance identification results and multi-stage coupling relationship, thereby improving the return water heat utilization efficiency and reducing heating steam extraction consumption and irreversible system losses.

[0046] Example 2: This embodiment describes the process of determining the effective injection segment set.

[0047] For the i-th candidate return water injection stage, the control system first calculates its thermal tolerance capacity. The thermal tolerance capacity is determined according to the following formula:

[0048] in, Indicates the first The thermal tolerance of each candidate recharge injection stage; Indicates the first Condensate flow rate of each candidate return water injection stage; This indicates the specific heat capacity of condensate; Indicates the first The maximum allowable condensate outlet temperature for each candidate return water injection stage; Indicates the first Current condensate outlet temperature of each candidate return water injection stage; This represents the safety margin factor.

[0049] when If the threshold value is less than the preset minimum acceptance threshold, it indicates that the candidate return water injection stage does not have sufficient capacity to absorb heat from the heating return water, and the candidate return water injection stage is removed from the set of valid injection stages.

[0050] The control system also calculates the thermal grade matching degree of the candidate return water injection stage. The thermal grade matching degree can be determined based on the temperature difference between the heating return water temperature and the condensate temperature of the candidate return water injection stage, the corresponding extraction steam saturation temperature, and the terminal temperature difference of the low-pressure heater.

[0051] In one implementation, the thermal grade matching degree is calculated as follows:

[0052] in, Indicates the first Thermal grade matching degree of each candidate return water injection stage; Indicates the return water temperature for heating; Indicates the first Condensate temperature of each candidate return water injection stage; Indicates the first The corresponding extraction steam saturation temperature of each candidate return water injection stage; Indicates the first The differential pressure at the low-pressure heater terminals of each candidate return water injection stage; , , These represent the weight coefficients of the corresponding evaluation items.

[0053] when When the grade exceeds the preset grade matching threshold, the candidate return water injection stage is determined to meet the thermal grade matching condition.

[0054] The control system also calculates the availability of regulation based on the remaining opening of the return water injection regulating valve, the regulating sensitivity, historical tracking errors, and fault conditions. In one embodiment, the availability of regulation is determined as follows:

[0055] in, Indicates the first The adjustability of each candidate return water injection stage; This indicates the remaining opening degree of the corresponding return water injection regulating valve; This indicates the adjustment sensitivity of the corresponding return water injection regulating valve; This indicates the historical tracking error of the corresponding return water injection regulating valve; This indicates a fault status indicator; it is used when the control valve is faulty. Select 1, when the regulating valve is not faulty. Set to 0; , , , These represent the weight coefficients of the corresponding evaluation items.

[0056] when When the value is greater than the preset adjustment availability threshold, the candidate return water injection stage is determined to meet the adjustment availability condition.

[0057] Ultimately, the control system identifies candidate return water injection stages that meet preset conditions in terms of heat acceptance capacity, thermal grade matching, and regulation availability as effective injection stages, thus forming a set of effective injection stages:

[0058] in, Indicates the set of valid injection segments; These represent the effective injection segments obtained through screening; This indicates the number of valid injection stages within the current control cycle.

[0059] This embodiment can avoid distributing the heating return water to a stage where the temperature is close to the upper limit, the valve adjustment capacity is insufficient, or the heat quality is mismatched, thereby improving the safety and effectiveness of the heating return water heat distribution.

[0060] Example 3: This embodiment describes the process of dividing the basic heat distribution and the identified disturbance heat.

[0061] The control system is based on the total flow rate of the heating return water. Heating return water temperature and reference condensate temperature Calculate the total heat of the heating return water The calculation formula is as follows:

[0062] in, This indicates the total heat of the heating return water; Indicates the total flow rate of the heating return water; This indicates the specific heat capacity of the heating return water; Indicates the return water temperature for heating; This indicates the reference condensate temperature.

[0063] Within one control cycle, the control system will The main part serves as the basic distribution of heat. The remaining portion will be used to identify the heat of disturbance. Identify disturbance heat It can be set to the total heat of the heating return water. 1% to 10%, that is:

[0064] in, This is the disturbance scaling factor. The range of values ​​for is:

[0065] Basal distributed heat for:

[0066] When the unit is operating relatively stably, λ can be taken as 5%; when the unit's electrical load, heating load, or heating return water temperature fluctuates greatly, λ can be taken as 1% to 3% to reduce the impact of disturbances on heating stability.

[0067] Basal distributed heat The heat is allocated to the corresponding effective injection stage according to the allocation scheme determined in the previous control cycle to maintain stable heating load. Disturbance heat is identified. Superimposed on the base distribution heat, it is used to identify the actual thermodynamic response of each effective injection stage.

[0068] During any control cycle, the control system ensures that the sum of the base heat distribution and the identified disturbance heat of any effective injection stage does not exceed the heat tolerance capacity of that effective injection stage, under the following constraints:

[0069] in, Indicates the first The basic heat distribution of each effective injection stage; Indicates the first Identification of perturbation heat in each effective injection stage; Indicates the first The heat acceptability of each effective injection stage.

[0070] At the same time, the sum of the base distribution heat of all effective injection stages and the sum of the identified perturbation heat satisfy the following:

[0071] in, This indicates that the summation is performed over all valid injection stages.

[0072] By dividing the heat return water into basic distribution heat and identified disturbance heat, this embodiment can achieve online identification of the thermal response of different injection stages while maintaining a stable heating load.

[0073] Example 4: This embodiment describes the preset encoding perturbation method.

[0074] Within the set of effective injection stages, the control system configures coded perturbation sequences for each effective injection stage. The coded perturbation sequences can be pseudo-random binary coded sequences, Hadamard coded sequences, or zero-mean orthogonal coded sequences. Each coded perturbation sequence includes at least two states: a positive perturbation state, a negative perturbation state, and a zero perturbation state.

[0075] Taking Hadamard-coded perturbation as an example, if there are currently four effective injection stages, the control system selects four sets of mutually orthogonal coding sequences, each corresponding to one of the four effective injection stages. Within the same identification period, each effective injection stage receives the identified perturbation heat according to its corresponding coding sequence.

[0076] The encoded perturbation sequences corresponding to different effective injection levels satisfy the low correlation condition, and the correlation coefficient is calculated according to the following formula:

[0077] in, Indicates the first The encoded perturbation sequence and the first The correlation coefficient between the coded perturbation sequences; Indicates the length of the encoded sequence; Indicates the first The encoded perturbation sequence in the first... The encoded value of each sampling point; Indicates the first The encoded perturbation sequence in the first... The encoded value of each sampling point; Indicates to to Sum all the sample points.

[0078] When |Rij| is less than the preset correlation threshold, the i-th coded perturbation sequence and the j-th coded perturbation sequence are considered to meet the low correlation requirement.

[0079] In actual implementation, a positive disturbance state indicates that a small amount of identified disturbance heat is added to the corresponding effective injection stage; a negative disturbance state indicates that a small amount of injected heat is reduced in the corresponding effective injection stage, and the reduced heat is transferred to the balance channel or other effective injection stages that meet safety constraints; a zero disturbance state indicates that the effective injection stage maintains the current basic heat allocation unchanged.

[0080] For the i-th effective injection stage, the identified perturbation heat at the k-th sampling point can be determined as follows:

[0081] in, ( ) indicates the first The effective injection stage is in the first Identification of disturbance heat at each sampling point; Indicates the first The effective injection stage is in the first The encoded value of each sampling point; Indicates assignment to the first The amplitude of disturbance heat in each effective injection stage.

[0082] This embodiment can simultaneously apply perturbations to multiple valid injection stages within the same identification period, and obtain the independent responses of each valid injection stage through decoding. Compared to the method of perturbing one by one, this embodiment can shorten the identification period and improve the dynamic optimization speed.

[0083] Example 5: This embodiment describes the process of collecting and processing runtime response data.

[0084] During the identification of the effects of heat disturbance, the control system collects at least some of the following data for each effective injection stage: condensate inlet temperature change, condensate outlet temperature change, pressure change, steam extraction rate change, low-pressure heater terminal temperature difference change, heating load change, unit heat consumption change, and the actual opening change of the corresponding return water injection regulating valve.

[0085] Because there is a certain lag between the action of the regulating valve and the resulting changes in temperature, pressure, or steam extraction rate of the heating return water, the control system performs time-lag compensation on the collected operational response data. Specifically, the control system determines the moment when the disturbance heat begins to be injected. It also detects the moments when significant changes occur in the corresponding temperature response, pressure response, steam extraction rate response, or unit heat consumption response. ,Will and The time difference is taken as the response lag time τi of the effective injection stage, and the calculation formula is as follows:

[0086] in, Indicates the first The response lag time of each effective injection stage; Indicates the moment when the heat of disturbance begins to be injected; This indicates the moment when the corresponding runtime response changes significantly.

[0087] Subsequently, the control system follows the response lag time. The operational response data is shifted or aligned to ensure that the identified disturbance heat input sequence corresponds to the operational response data in time.

[0088] After time-delay compensation is completed, the control system removes the baseline operating response without identifying the heat of disturbance, obtaining the dynamic response component caused by the identified heat of disturbance. Taking the condensate outlet temperature as an example, the dynamic response component is determined according to the following formula:

[0089] in, Indicates the first Each effective injection stage at time... The dynamic response component of condensate outlet temperature; This indicates the condensate outlet temperature after applying the identified disturbance heat and undergoing time-delay compensation; This indicates the base condensate outlet temperature when no identification disturbance heat is applied.

[0090] The steam extraction rate response can be determined using the following formula:

[0091] in, Indicates the first The reduction in steam extraction for heating corresponding to each effective injection stage; This indicates the base extraction steam volume without applying identification disturbance heat. This indicates the amount of steam extracted after the application of identified disturbance heat and time-delay compensation.

[0092] Subsequently, the control system filters the dynamic response components to remove sensor noise, short-term fluctuations, and random disturbances unrelated to heating return water disturbances, thus obtaining net response data.

[0093] This embodiment improves the accuracy of identifying the unit heat gain relationship and thermodynamic coupling relationship through time delay compensation, steady-state component elimination and filtering, and avoids misjudging the natural fluctuation of unit load as a thermodynamic response caused by the injection of heating return water.

[0094] Example 6: This embodiment illustrates the online identification process of unit heat gain relationship and thermodynamic coupling relationship.

[0095] The control system calculates the unit heat gain coefficient for each effective injection stage based on the coded disturbance sequence and net response data. The unit heat gain coefficient can be calculated based on at least two of the following: the change in total entropy production of the system caused by a unit of heating return water heat injection into the corresponding effective injection stage; the reduction in heating steam extraction; the change in equivalent power supply coal consumption; and the change in heating load deviation.

[0096] For the i-th effective injection stage, its unit heat gain coefficient Bi is calculated according to the following formula:

[0097] in, Indicates the first The unit heat gain coefficient of each effective injection stage; This represents the change in total entropy production of the system caused by a unit of heat from the disturbance; This indicates a reduction in the amount of steam extracted for heating. This represents the change in equivalent coal consumption for power supply; This indicates the amount of change in heating load deviation; Indicates injection of the first The heat generated by the disturbance in each effective injection stage; , , , These represent the weight coefficients of the corresponding evaluation items.

[0098] The larger Bi is, the higher the overall benefit generated after the unit heat return water is injected into the i-th effective injection stage.

[0099] In one implementation, the change in total entropy production of the system, ΔSi, can be determined comprehensively based on the changes in heat exchange temperature difference, extraction steam parameters, and condensate temperature; the change in equivalent coal consumption for power generation, Δbi, can be calculated based on the unit's heat consumption response and changes in power generation load; and the change in heating load deviation, ΔHi, can be determined based on the change in the difference between the actual heating supply and the target heating supply.

[0100] The control system also calculates the thermodynamic coupling coefficient between different effective injection stages. The thermodynamic coupling coefficient is used to characterize the degree of influence of changes in the heating return water injection rate of one effective injection stage on the changes in condensate outlet temperature, extraction steam rate, terminal temperature difference, or entropy production of another effective injection stage.

[0101] In one implementation, the thermodynamic coupling coefficient mij of the i-th effective injection stage to the j-th effective injection stage is determined as follows:

[0102] in, Indicates the first The effective injection stage for the first Thermo-coupling coefficient of each effective injection stage; Indicates the first The changes in condensate outlet temperature, extraction steam rate, terminal temperature difference, or entropy production of each effective injection stage. Indicates the first The change in injection heat in each effective injection stage.

[0103] The stage coupling matrix M is composed of the thermo-coupling coefficients of each effective injection stage:

[0104] in, Represents the segment coupling matrix; Indicates the first The effect of the injection heat change of the first effective injection stage on the second The degree of influence of the thermal state of each effective injection stage; Indicates the first The self-response relationship of each effective injection level segment; when Not equal to hour, This indicates the cross-influence relationship between different effective injection stages.

[0105] When a non-diagonal element When the temperature exceeds the preset coupling threshold, it indicates a strong thermal coupling between the i-th and j-th effective injection stages. During subsequent rolling optimization, the control system sets joint constraints on the heat distribution between these two effective injection stages to prevent excessive local temperature rise or abnormal end-to-end temperature differences caused by the simultaneous increase in injected heat from the two strongly coupled stages.

[0106] Example 7: This embodiment illustrates the process of establishing and solving the rolling optimization model.

[0107] The control system establishes a rolling optimization model based on the unit heat gain relationship, thermodynamic coupling relationship, heat acceptance capacity of each effective injection stage, and heating load demand.

[0108] The objective function of the rolling optimization model can be expressed as:

[0109] in, This represents the objective function value of the rolling optimization model; This represents the total entropy production of the system within the prediction period; This indicates the amount of steam consumed during the heating extraction period; This represents the equivalent coal consumption for power generation within the forecast period; Indicates the deviation of heating load; Indicates the first The change in opening degree of the return water injection regulating valve between adjacent control cycles; , , , , These represent the weight coefficients of the corresponding target items; This represents the summation of the squares of the opening changes of all return water injection regulating valves.

[0110] The heat balance constraint of the rolling optimization model is:

[0111] in, Indicates the first The heat distribution of each effective injection stage; This indicates the amount of heat that can be distributed in the heating return water; This represents the sum of heat distributed across all effective injection stages.

[0112] The heat absorption capacity constraint of the rolling optimization model is:

[0113] in, Indicates the first The heat distribution of each effective injection stage; Indicates the first The heat acceptability of each effective injection stage.

[0114] The condensate outlet temperature constraint for the rolling optimization model is:

[0115] in, Indicates the first The condensate outlet temperature of each effective injection stage; Indicates the first The highest permissible condensate outlet temperature for each effective injection stage.

[0116] The valve opening constraint for the rolling optimization model is:

[0117]

[0118] in, Indicates the first The current target opening degree of the return water injection regulating valve; Indicates the first The opening degree of the return water injection regulating valve in the previous control cycle; Indicates the first Minimum allowable opening of each return water injection regulating valve; Indicates the first The maximum allowable opening of each return water injection regulating valve; Indicates the first The maximum allowable change in opening degree of the return water injection regulating valve within adjacent control cycles.

[0119] The heating load deviation constraint for the rolling optimization model is:

[0120] in, Indicates the actual heating load; Indicates the target heating load; This indicates the upper limit of the allowable heating load deviation.

[0121] When any thermal coupling coefficient in the stage coupling matrix exceeds a preset coupling threshold, the control system sets a joint allocation constraint on the corresponding two effective injection stages in the rolling optimization model. The joint allocation constraint can limit the simultaneous increase of the allocated heat of the two effective injection stages, or keep the ratio of the allocated heat of the two effective injection stages within a preset range.

[0122] For example, for the i-th and j-th effective injection segments that have a strong coupling relationship, the following proportional constraint can be set:

[0123] in, Indicates the first The effective injection stage and the first The lower limit of the heat distribution ratio between effective injection stages; Indicates the first The effective injection stage and the first The upper limit of the heat distribution ratio between effective injection stages.

[0124] The control system solves the rolling optimization model to obtain the distributed heat of each effective injection stage within the current control cycle. Subsequently, the control system enters the next control cycle and re-solves the model based on newly acquired real-time operating parameters, newly identified unit heat gain relationships, and thermodynamic coupling relationships, thereby achieving rolling optimization control.

[0125] Example 8: This embodiment describes the process of generating the opening command for the return water injection regulating valve.

[0126] The control system determines the allocated heat Qi for each effective injection stage based on the optimal allocation scheme obtained from the rolling optimization model. For the i-th effective injection stage, the target opening Vi_target of its corresponding return water injection regulating valve is determined according to the following formula:

[0127] in, Indicates the first The target opening degree of the return water injection regulating valve; Indicates the first The heat distribution of each effective injection stage; This indicates that the return water for heating can be distributed with heat.

[0128] To avoid abrupt changes in valve opening, the control system generates a smoothed valve opening command based on the current opening Vi_current, the target opening Vi_target, and the maximum allowable change in opening ΔVmax_i.

[0129] When the target opening is greater than the current opening and the difference between the two is greater than the maximum allowable change in opening:

[0130] When the target opening is less than the current opening and the difference between the two is greater than the maximum allowable change in opening:

[0131] When the difference between the target opening and the current opening is not greater than the maximum allowable change in opening:

[0132] in, Indicates the first The actual opening command issued for each return water injection regulating valve; Indicates the first Current opening degree of the return water injection regulating valve; Indicates the first Target opening degree of the return water injection regulating valve; Indicates the first The maximum allowable single-cycle opening change of the return water injection regulating valve.

[0133] After generating the opening command, the control system sends Vi_cmd to the corresponding return water injection regulating valve, so that the heating return water is injected into the corresponding effective injection stage according to the optimal distribution scheme. By smoothing the valve opening, fluctuations in condensate temperature, local pressure fluctuations, or heating load disturbances caused by rapid valve action can be avoided.

[0134] Example 9: This embodiment describes the model update and safe rollback process.

[0135] After the heat distribution of the heating return water is executed, the control system obtains the actual condensate outlet temperature, actual steam extraction rate, actual heating load, actual equivalent coal consumption for power supply, and actual valve opening within the current control cycle, and compares the above actual operating response with the predicted operating response corresponding to the rolling optimization model.

[0136] In one implementation, the prediction bias E is calculated as follows:

[0137] in, Indicates prediction bias; This indicates the actual condensate outlet temperature; This indicates the predicted condensate outlet temperature; This indicates the actual amount of steam extracted for heating. This indicates the predicted steam extraction volume for heating. Indicates the actual heating load; This indicates the predicted heating load; This represents the actual equivalent coal consumption for power supply; This indicates the predicted equivalent coal consumption for power generation; , , , These represent the weighting coefficients of the corresponding deviation terms.

[0138] When E exceeds the preset model correction threshold, the control system recalculates the unit heat gain relationship and thermodynamic coupling relationship. Specifically, the control system acquires the currently identified unit heat gain relationship and thermodynamic coupling relationship and performs a weighted fusion with the historical identification results.

[0139] The updated formula for the unit heat benefit relationship is as follows:

[0140] in, This indicates the updated unit heat gain relationship; This indicates the unit heat gain relationship currently identified; This indicates the relationship between historical unit heat gain and loss. This represents the fusion weight of the current identification result.

[0141] The update formula for the segment coupling matrix is ​​as follows:

[0142] in, This represents the updated segmental coupling matrix; This represents the segment coupling matrix obtained from the current identification. Represents the historical segment coupling matrix; This represents the fusion weight of the current identification result.

[0143] When the rate of change of the unit's electrical load, heating load, or heating return water temperature exceeds the preset rate of change threshold, it indicates that the current operating condition is changing rapidly. The control system increases the weight μ of the current identification result in the weighted fusion. When the unit is running stably, the control system decreases μ to improve control stability.

[0144] During operation, if any of the following abnormal conditions are detected, the control system will stop applying the identified disturbance heat and switch the distribution mode of the heating return water heat to the safety back-off mode: The condensate outlet temperature of any effective injection stage exceeds the preset safety temperature; The deviation between the actual opening and the target opening of any return water injection regulating valve exceeds the preset valve failure threshold; The fluctuation range of the heating return water flow exceeds the preset flow fluctuation threshold. The deviation between the system's heat dissipation response and the predicted heat dissipation response exceeds the preset deviation threshold for several consecutive control cycles.

[0145] In the safety backoff mode, the control system closes the return water injection regulating valve corresponding to the abnormal effective injection stage and transfers the distributed heat of the abnormal effective injection stage to other effective injection stages that meet safety constraints and have the optimal unit heat gain relationship. If there are no other effective injection stages that meet the safety constraints, the control system switches the heating return water to the preset fixed return water channel.

[0146] After the safety rollback mode has been in effect for a preset time, the control system re-acquires real-time operating parameters and re-executes the steps for determining the effective injection stage set. This method ensures safe unit operation in the event of abnormal conditions or equipment failures, and restores self-identification and optimized allocation control once the anomaly is resolved.

[0147] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for optimizing and controlling the heating efficiency of a combined heat and power (CHP) unit, characterized in that, Includes the following steps: The real-time operating parameters of different candidate return water injection stages in the regenerative system of a cogeneration unit are obtained, and the effective injection stage set is determined based on the real-time operating parameters. Within the effective injection stage set, the heating return water heat is divided into basic distribution heat and identified disturbance heat. The identified disturbance heat is superimposed and distributed to at least two effective injection stages according to the preset coding disturbance method. Collect operational response data of each effective injection stage under the influence of identified heat disturbance, and identify the unit heat gain relationship of each effective injection stage and the thermodynamic coupling relationship between different effective injection stages online based on the operational response data; Based on the unit heat gain relationship, thermodynamic coupling relationship, heat acceptance constraints of each effective injection stage, and heating load demand, solve the optimal distribution scheme of heating return water heat among each effective injection stage within the current control cycle. Generate the return water injection regulating valve opening command corresponding to each effective injection stage according to the optimal allocation scheme, and execute the heating return water heat allocation according to the return water injection regulating valve opening command. After the heat distribution of the heating return water is implemented, the actual operating response is compared with the predicted operating response, and the unit heat gain relationship and thermodynamic coupling relationship are updated based on the comparison results.

2. The method for optimizing and controlling the heating efficiency of a combined heat and power unit according to claim 1, characterized in that, The candidate return water injection stage includes at least two of the following: the condensate side inlet of the low-pressure heater, the condensate side outlet of the low-pressure heater, the condensate connection pipe section between adjacent low-pressure heaters, the condensate pump outlet pipe section, and the condensate pipe section before the deaerator inlet. Real-time operating parameters include condensate inlet temperature, condensate outlet temperature, condensate inlet pressure, condensate outlet pressure, condensate flow rate, extraction steam pressure, extraction steam temperature, extraction steam volume, heating return water temperature, heating return water flow rate, unit electrical load, heating load, low-pressure heater terminal differential pressure, condensate temperature, and parameters in the current opening of the return water injection regulating valve.

3. The method for optimizing and controlling the heating efficiency of a combined heat and power unit according to claim 1, characterized in that, The specific method for determining the set of valid injection segments based on real-time runtime parameters is as follows: The heat acceptance capacity of the candidate return water injection stage is calculated based on the current condensate outlet temperature, the maximum allowable condensate outlet temperature, the condensate flow rate, and the condensate specific heat capacity. The thermal quality matching degree of the candidate return water injection stage is calculated based on the temperature difference between the heating return water temperature and the condensate temperature of the candidate return water injection stage, the extraction steam saturation temperature of the corresponding stage, and the terminal difference of the low-pressure heater. The availability of regulation for each candidate return water injection stage is calculated based on the remaining opening, regulation sensitivity, historical tracking error, and fault status of the return water injection regulating valve. Candidate return water injection stages that meet preset conditions in terms of heat acceptance capacity, thermal grade matching degree, and regulation availability are identified as effective injection stages and are used as the set of effective injection stages.

4. The method for optimizing and controlling the heating efficiency of a combined heat and power unit according to claim 1, characterized in that, The specific methods for dividing the return water heat into basic distributed heat and identified disturbance heat are as follows: A portion of the total heat from the heating return water is used as the base heat allocation and distributed to the corresponding effective injection stage according to the allocation scheme determined in the previous control cycle. The remaining portion of the total heat of the heating return water is used as the identified disturbance heat, which is 1% to 10% of the total heat of the heating return water, and the sum of the base-allocated heat and the identified disturbance heat of any effective injection stage does not exceed the heat acceptance capacity of that effective injection stage.

5. The method for optimizing and controlling the heating efficiency of a combined heat and power unit according to claim 1, characterized in that, The specific method for superimposing and distributing the identified perturbation heat to at least two effective injection stages according to the preset coding perturbation method is as follows: Configure coded perturbation sequences for different effective injection stages; Within the same identification period, the identification perturbation heat is superimposed and distributed to each effective injection stage according to the corresponding coded perturbation sequence. The correlation coefficient between the coded perturbation sequences corresponding to different effective injection stages is less than the preset correlation threshold, so that multiple effective injection stages can apply identification perturbation heat synchronously within the same identification period. The independent response of each effective injection stage is obtained by decoding and separation. The coded perturbation sequence is a pseudo-random binary coded sequence, a Hadamard coded sequence, or a zero-mean orthogonal coded sequence.

6. The method for optimizing and controlling the heating efficiency of a combined heat and power unit according to claim 1, characterized in that, The specific method for identifying the unit heat gain relationship of each effective injection stage and the thermodynamic coupling relationship between different effective injection stages based on operational response data is as follows: Collect partial data from each effective injection stage, including changes in condensate inlet temperature, condensate outlet temperature, pressure, steam extraction rate, low-pressure heater terminal temperature difference, heating load, unit heat consumption, and the actual opening change of the corresponding return water injection regulating valve. The collected operational response data is subjected to time delay compensation, steady-state component removal, and filtering to obtain net response data; Based on the coded perturbation sequence and net response data, the unit heat gain coefficient of each effective injection stage is calculated, and the thermal coupling coefficient between different effective injection stages is also calculated.

7. The method for optimizing and controlling the heating efficiency of a combined heat and power unit according to claim 6, characterized in that, The unit heat revenue coefficient is calculated based on at least two of the following: the change in total entropy production of the system caused by the unit heat injection of the return water to the corresponding effective injection stage, the reduction in steam extraction for heating, the change in equivalent coal consumption for power generation, and the change in heating load deviation. Thermo-coupling coefficient is used to characterize the degree of influence of the change in the heating return water injection rate of one effective injection stage on the changes in condensate outlet temperature, extraction steam rate, terminal temperature difference, or entropy production of another effective injection stage. The segment coupling matrix is ​​composed of the thermo-mechanical coupling coefficients of each effective injection segment. The diagonal elements in the segment coupling matrix represent the self-response relationship of the corresponding effective injection segment, and the off-diagonal elements represent the cross-influence relationship between different effective injection segments.

8. The method for optimizing and controlling the heating efficiency of a combined heat and power unit according to claim 1, characterized in that, Based on the unit heat gain relationship, thermodynamic coupling relationship, heat acceptance constraints of each effective injection stage, and heating load demand, the specific method for solving the optimal distribution scheme of heating return water heat among each effective injection stage within the current control cycle is as follows: A rolling optimization model is established. The objective function of the rolling optimization model includes at least two of the following: minimizing the total entropy production of the system, minimizing the steam consumption for heating extraction, minimizing the equivalent coal consumption for power generation, minimizing the heating load deviation, and penalizing the change in the opening of the return water injection regulating valve. The constraints of the rolling optimization model include heat balance constraints, heat acceptance capacity constraints, condensate outlet temperature constraints, valve opening constraints, and heating load deviation constraints. Based on the unit heat gain relationship, thermodynamic coupling relationship, heat acceptance constraints of each effective injection stage, and heating load demand, the distributed heat of each effective injection stage in the current control cycle can be obtained under the condition that the constraints are met.

9. The method for optimizing and controlling the heating efficiency of a combined heat and power unit according to claim 1, characterized in that, After the heat distribution of the heating return water is implemented, the actual operating response is compared with the predicted operating response. The specific method for updating the unit heat gain relationship and thermodynamic coupling relationship based on the comparison results is as follows: Acquire partial data from the actual condensate outlet temperature, actual steam extraction rate, actual heating load, actual equivalent coal consumption for power generation, and actual valve opening within the current control cycle; Compare the actual operating response with the predicted operating response corresponding to the rolling optimization model; When the comparison deviation exceeds the preset model correction threshold, the unit heat gain relationship and thermodynamic coupling relationship are recalculated. When the condensate outlet temperature of any effective injection stage exceeds the preset safety temperature, the deviation between the actual opening and the target opening of any return water injection regulating valve exceeds the preset valve fault threshold, the fluctuation amplitude of the heating return water flow exceeds the preset flow fluctuation threshold, or the deviation between the system heat consumption response and the predicted heat consumption response exceeds the preset deviation threshold for multiple consecutive control cycles, the application of identification disturbance heat will be stopped, and the distribution mode of heating return water heat will be switched to safety retreat mode.

10. A heating efficiency optimization control system for a combined heat and power (CHP) unit, characterized in that, include: The parameter acquisition module is used to acquire real-time operating parameters of different candidate return water injection stages in the regenerative system of a cogeneration unit, and to determine the set of effective injection stages based on the real-time operating parameters. The disturbance distribution module is used to divide the heating return water heat into basic distribution heat and identified disturbance heat within the effective injection stage set, and to distribute the identified disturbance heat to at least two effective injection stages according to a preset coded disturbance method. The response identification module is used to collect the operating response data of each effective injection stage under the action of identified disturbance heat, and to identify the unit heat gain relationship of each effective injection stage and the thermodynamic coupling relationship between different effective injection stages online based on the operating response data. The optimization solution module is used to solve the optimal distribution scheme of heating return water heat among each effective injection stage within the current control cycle, based on the unit heat gain relationship, thermodynamic coupling relationship, heat acceptance constraints of each effective injection stage, and heating load demand. The valve control module is used to generate the opening command of the return water injection regulating valve corresponding to each effective injection stage according to the optimal allocation scheme, and to execute the heat distribution of the heating return water according to the opening command of the return water injection regulating valve. The model update module is used to compare the actual operating response with the predicted operating response after the heat distribution of the heating supply and return water is executed, and to update the unit heat gain relationship and thermodynamic coupling relationship based on the comparison results.

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