CN-121976867-A - Waste heat recovery system for improving peak regulation capacity of thermal power generating unit

CN121976867ACN 121976867 ACN121976867 ACN 121976867ACN-121976867-A

Abstract

The invention relates to the field of peak regulation and waste heat utilization of thermal power units, and discloses a waste heat recovery method and a waste heat recovery system for improving the peak regulation capacity of a thermal power unit. The method comprises the steps of carrying out grade identification and cascade recovery on boiler exhaust gas of a thermal power unit and circulating water waste heat of a steam turbine, respectively obtaining high-grade heat energy and low-grade heat energy, collecting the high-grade heat energy and the low-grade heat energy into a heat storage device for storage and integration to form unified schedulable heat energy storage, receiving a power grid regulation signal in real time through an intelligent control system, synchronously monitoring an energy storage state parameter of the heat storage device and a real-time operation boundary parameter of the thermal power unit, comparing the power grid regulation signal with the energy storage state parameter and the operation boundary parameter, generating a control instruction according to a preset threshold strategy, and feeding heat energy released by the heat storage device according to needs back to a thermal power unit thermodynamic system according to the control instruction. The invention realizes the efficient recovery of waste heat resources and the intelligent response of the power grid demand, and remarkably improves the peak shaving capacity and the running economy of the thermal power generating unit.

Inventors

LI HAIHAO
Xiao Dongge
NIU YONGJUN
ZHANG XIAOFENG
Ju Wutao
DU YUYAO
Zuo Xuemeng

Assignees

华能铜川照金煤电有限公司

Dates

Publication Date: 20260505
Application Date: 20260128

Claims (10)

1. A waste heat recovery method for improving peak regulation capacity of a thermal power generating unit is characterized by comprising the following steps: carrying out grade identification and cascade recovery on boiler exhaust gas of a thermal power unit and circulating water waste heat of a steam turbine to respectively obtain high-grade heat energy and low-grade heat energy; The high-grade heat energy and the low-grade heat energy are collected into a heat storage device for storage and integration, so that unified and schedulable heat energy storage is formed; Receiving a power grid regulation signal in real time through an intelligent control system, and synchronously monitoring an energy storage state parameter of the heat storage device and a real-time operation boundary parameter of the thermal power unit; Comparing the power grid regulation signal with the energy storage state parameter and the operation boundary parameter, and generating a control instruction according to a preset threshold strategy; and according to the control instruction, feeding the heat energy released by the heat storage device according to the requirement back to a thermodynamic system of the thermal power unit.
2. The waste heat recovery method for improving peak shaving capacity of a thermal power generating unit according to claim 1, wherein the step recovery and the grade identification of waste heat of boiler exhaust gas and turbine circulating water of the thermal power generating unit respectively obtain high-grade heat energy and low-grade heat energy, comprising: Based on a preset temperature threshold value, carrying out grade identification on the boiler exhaust gas and the circulating water waste heat of the steam turbine, and dividing the boiler exhaust gas and the circulating water waste heat into high-grade waste heat and low-grade waste heat; Introducing the high-grade residual heat into a first recovery loop for recovery to obtain the high-grade heat; And introducing the low-grade residual heat into a second recovery loop for recovery and temperature raising to obtain the low-grade heat.
3. The waste heat recovery method for improving peak shaving capacity of thermal power generating unit according to claim 2, wherein the collecting the high and low grade heat energy into the heat storage device for storage and integration to form unified and schedulable heat energy storage comprises: setting a target energy storage temperature range of the heat storage device; According to the target energy storage temperature range, adjusting the mixing proportion of the high-grade heat energy and the low-grade heat energy; And storing the mixed heat energy in the heat storage device to form heat energy storage with stable temperature and energy density.
4. The waste heat recovery method for improving peak shaving capacity of a thermal power generating unit according to claim 3, wherein the method for receiving the power grid regulation signal in real time through the intelligent control system and synchronously monitoring the energy storage state parameter of the heat storage device and the real-time operation boundary parameter of the thermal power generating unit comprises the following steps: receiving a regulation signal from a power system regulation main body in real time; Synchronously monitoring energy storage state parameters of the heat storage device, wherein the energy storage state parameters comprise the temperature, the pressure and the heat storage capacity of a heat storage medium; and synchronously monitoring real-time operation boundary parameters of the thermal power generating unit, wherein the operation boundary parameters comprise the current output force of the unit, the minimum technical output force, the boiler load rate and main steam parameters.
5. The method for recovering waste heat for improving peak shaving capacity of thermal power generating unit according to claim 4, wherein comparing said power grid regulation signal with said energy storage state parameter and said operation boundary parameter, generating a control command according to a preset threshold strategy, comprises: determining a current peak regulation demand mode of the thermal power unit according to the power grid regulation signal; Setting a corresponding control target priority and an associated threshold set for the peak shaving demand mode; comparing the energy storage state parameter of the heat storage device and the operation boundary parameter of the thermal power generating unit with the threshold set to generate a comparison result; and generating instructions of the heat storage device among different modes according to the comparison result and the control target priority.
6. The method for recovering waste heat for improving peak shaving capacity of thermal power generating unit according to claim 5, wherein setting a corresponding control target priority and an associated threshold set for the peak shaving demand mode comprises: pre-storing a basic threshold set matched with different peak shaving demand modes; According to time scale information carried in the power grid regulation and control signal, carrying out dynamic offset adjustment on key thresholds in the basic threshold set; And on-line compensation correction is carried out on the threshold value related to the charge and discharge rate based on the real-time energy storage density of the heat storage device.
7. The method for recovering waste heat for improving peak shaving capacity of thermal power generating unit according to claim 6, wherein generating the instruction of the thermal storage device between different modes according to the comparison result and the control target priority comprises: Converting the comparison result into a deviation degree quantization value of each control target constraint condition; Weighting and synthesizing each deviation quantized value according to the control target priority, and generating a system optimization index; and matching the system optimization index with a preset command triggering threshold value, and mapping out a specific operation mode command and a specific power command of the heat storage device.
8. The waste heat recovery method for improving peak shaving capacity of a thermal power generating unit according to claim 5, further comprising: Invoking a system model, and predicting the key states of the unit and the energy storage in a scheduling period in the future according to the control instruction; Checking the prediction state and the safe operation boundary, and evaluating the response performance of the prediction state and the safe operation boundary to the power grid regulation signal; and according to the verification and evaluation result, selecting to directly execute, execute after correction or replace to be a standby safety strategy to execute the control instruction.
9. The waste heat recovery method for improving peak shaving capacity of a thermal power generating unit according to claim 5, wherein according to the control command, the thermal energy released by the thermal storage device according to need is fed back to a thermal power generating unit thermodynamic system, and the method comprises the following steps: Analyzing the control instruction to determine a target feedback path and release power; according to the target feedback path, controlling valve switching, and guiding heat energy released by the heat storage device to a preset thermodynamic system interface; And adjusting the flow of the released heat energy to be matched with parameters at the interface of the thermodynamic system.
10. Waste heat recovery system for improving peak shaving capacity of thermal power generating unit, which is characterized by comprising: The waste heat recovery module is used for carrying out grade identification and cascade recovery on the waste heat of boiler exhaust gas and turbine circulating water of the thermal power generating unit, and respectively obtaining high-grade heat energy and low-grade heat energy; The heat energy storage and scheduling module is used for collecting the high-grade heat energy and the low-grade heat energy into the heat storage device for storage and integration to form unified and schedulable heat energy storage; the intelligent sensing and communication module is used for receiving the power grid regulation and control signal in real time through the intelligent control system and synchronously monitoring the energy storage state parameter of the heat storage device and the real-time operation boundary parameter of the thermal power generating unit; The intelligent decision module is used for comparing the power grid regulation and control signal with the energy storage state parameter and the operation boundary parameter and generating a control instruction according to a preset threshold strategy; and the heat energy feedback execution module is used for feeding back the heat energy released by the heat storage device according to the needs to the thermal power unit thermodynamic system according to the control instruction.

Description

Waste heat recovery system for improving peak regulation capacity of thermal power generating unit Technical Field The application relates to the field of peak regulation and waste heat utilization of thermal power units, in particular to a waste heat recovery method and a waste heat recovery system for improving the peak regulation capacity of a thermal power unit. Background Along with the large-scale grid connection of new energy, the demand of a power system for deep and rapid peak shaving of a thermal power unit is increasingly urgent. However, the thermal power generating unit is limited by the minimum technical output and the stable combustion boundary of the boiler, and the peak shaving capability has a bottleneck. Meanwhile, a large amount of boiler smoke exhaust and turbine circulating water waste heat generated by unit operation are usually directly discharged, so that energy waste is caused. The existing waste heat recovery technology focuses on heat energy utilization, dynamic coordination with power grid peak regulation requirements is not achieved, intelligent scheduling is lacking in energy storage and release processes, the recovered heat energy cannot be effectively converted into flexibly adjustable power generation capacity, and the value of the waste heat recovery technology in the aspect of improving the operation flexibility of a unit is limited. Therefore, a method and a system capable of intelligently coupling power grid signals and realizing the cooperative improvement of waste heat recovery and peak shaving capability are needed. Disclosure of Invention In order to solve the technical problems, the invention provides a waste heat recovery method and a waste heat recovery system for improving the peak regulation capacity of a thermal power unit. The method comprises the steps of carrying out grade identification and gradient recovery on waste heat of boiler exhaust gas and turbine circulating water to obtain heat energy with different grades, further integrating and storing the heat energy into unified and schedulable heat energy storage, receiving a power grid regulation and control signal in real time by an intelligent control system, integrating an energy storage state and a unit operation boundary, generating an optimized control instruction through a dynamic threshold strategy, and finally feeding back the heat energy released by a heat storage device to a thermodynamic system safely and accurately according to requirements. The invention realizes high-value utilization of waste heat resources and quick response of the power grid peak shaving instruction, effectively breaks through the inherent peak shaving bottleneck of the unit, and improves the running economy and the system flexibility. In some embodiments of the present application, a method for recovering waste heat for improving peak shaving capacity of a thermal power generating unit is provided, which is characterized by comprising: carrying out grade identification and cascade recovery on boiler exhaust gas of a thermal power unit and circulating water waste heat of a steam turbine to respectively obtain high-grade heat energy and low-grade heat energy; The high-grade heat energy and the low-grade heat energy are collected into a heat storage device for storage and integration, so that unified and schedulable heat energy storage is formed; Receiving a power grid regulation signal in real time through an intelligent control system, and synchronously monitoring an energy storage state parameter of the heat storage device and a real-time operation boundary parameter of the thermal power unit; Comparing the power grid regulation signal with the energy storage state parameter and the operation boundary parameter, and generating a control instruction according to a preset threshold strategy; and according to the control instruction, feeding the heat energy released by the heat storage device according to the requirement back to a thermodynamic system of the thermal power unit. In some embodiments of the present application, according to grade identification and cascade recovery of boiler exhaust gas and turbine circulating water waste heat of a thermal power generating unit, respectively obtaining high and low grade heat energy includes: Based on a preset temperature threshold value, carrying out grade identification on the boiler exhaust gas and the circulating water waste heat of the steam turbine, and dividing the boiler exhaust gas and the circulating water waste heat into high-grade waste heat and low-grade waste heat; Introducing the high-grade residual heat into a first recovery loop for recovery to obtain the high-grade heat; And introducing the low-grade residual heat into a second recovery loop for recovery and temperature raising to obtain the low-grade heat. In some embodiments of the present application, the collecting the high and low grade heat energy into the heat storage device for storage and integration