Steam pipe network pressure regulating and heat storage auxiliary coal power unit peak shaving operation system and method
By using a steam pipeline network pressure regulation and thermal storage system to assist coal-fired power units in peak shaving, a three-stage cylinder series structure and multi-valve regulation are adopted to optimize the thermal cycle. This solves the problems of high coupling between heating and power generation loads and poor peak shaving flexibility of coal-fired power units, realizes energy cascade utilization and precise control of steam supply load, and improves system stability and peak shaving efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XIAN THERMAL POWER RES INST CO LTD
- Filing Date
- 2026-02-28
- Publication Date
- 2026-05-29
AI Technical Summary
Existing coal-fired power units have a high degree of coupling between heating and power generation loads, poor peak-shaving flexibility, and difficulty in effectively reducing steam supply load and improving peak-shaving efficiency.
A steam pipeline pressure regulation and heat storage auxiliary coal-fired power unit peak shaving system is constructed. Through a three-stage cylinder series structure and multi-valve regulation, the steam energy is utilized in stages and precisely distributed. Combined with the condensing unit and heating and deoxygenation unit, the thermodynamic cycle is optimized to achieve steam pipeline pressure regulation and heat storage and steam supply load regulation.
It improves the energy utilization efficiency of the unit, reduces the steam supply load, enhances the system stability and flexibility, solves the problems of high coupling between heating and power generation loads and poor peak-shaving flexibility of traditional coal-fired power units, and realizes efficient cascade utilization and flexible control of steam energy.
Smart Images
Figure CN122106713A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of design and operation of coal-fired power unit coupled steam pressure regulating and energy storage systems, specifically to an operation system and method for peak shaving of coal-fired power units with steam pipeline pressure regulating and thermal storage assistance. Background Technology
[0002] Given the current energy endowment of being rich in coal but poor in oil and gas, coupled with large-scale urbanization, the clean and efficient utilization of coal is the primary means of providing centralized heating for residential use and steam for industrial applications. Industrial steam users include industries such as chemical, papermaking, food processing, and textiles, primarily located in the industrially developed southern regions. In recent years, with the rapid development of the market economy, the demand for steam from industrial enterprises has been continuously increasing.
[0003] According to statistics, the industrial steam supply in 2024 was 671.61 million gigajoules, equivalent to 228.44 million tons (2.94 gigajoules per ton of steam), with an average market price of approximately 39.7 yuan per gigajoul. The "coal-fired combined heat and power (CHP) + industrial steam supply network" model accounted for a significant portion of this supply. However, this high heat supply ratio restricts the flexible power generation of CHP units. Specifically, given a fixed boiler output in a coal-fired CHP unit, the steam consumed for heating reduces the turbine's work, resulting in a zero-sum game between heat production and power generation.
[0004] In the process of building a new power system with new energy as the main body, it is increasingly urgent to improve the ability of coal-fired power units to provide a safety net and make flexible adjustments in order to solve the problem of large-scale development of new energy power and the problem of its strong time-varying characteristics. To maximize or fully capture capacity charges, combined heat and power (CHP) units coupled with thermal storage systems achieve peak power generation through load shifting over time. Furthermore, these systems can also facilitate peak-to-valley power generation and arbitrage in the spot market. Currently, in enhancing the flexible regulation capabilities of coal-fired power units supplying industrial steam, coupled molten salt thermal storage systems are predominantly used, achieving significant improvements in deep peak-shaving capacity, peak load capacity, and rapid load shifting capabilities. However, these systems also face limitations such as high investment costs, large land area requirements, and complex system operation. Summary of the Invention
[0005] In order to overcome the defects of the existing technology, the purpose of this invention is to provide an operating system and method for peak shaving of coal-fired power units with steam network pressure regulation and thermal storage, so as to solve the technical problem of how to reduce the steam supply load of coal-fired power units and improve the operating efficiency of peak shaving of coal-fired power units with steam network pressure regulation and thermal storage.
[0006] This invention is achieved through the following technical solution: In a first aspect, the present invention provides an operating system for peak shaving of a steam pipeline pressure regulating and thermal storage auxiliary coal-fired power unit, including a boiler, regulating valve assembly, power unit, condensing unit and heating and deoxygenation unit; The output end of the boiler is connected to the input end of the power unit, the output end of the power unit is connected to the input end of the condensing unit, the output end of the condensing unit is connected to the input end of the heating and deoxygenating unit, and the output end of the heating and deoxygenating unit is connected to the input end of the boiler, forming a thermodynamic circulation loop. The heating end of the boiler and the working unit is connected to the heat user through a pipeline. The regulating valve assembly is installed on the pipeline between the heating end of the boiler and the working unit and the heat user, and is used to regulate the heat through the regulating valve assembly.
[0007] Preferably, the working unit includes a high-pressure cylinder, an intermediate-pressure cylinder, and a low-pressure cylinder; The output end of the boiler is connected to the input end of the high-pressure cylinder, the output end of the high-pressure cylinder is connected to the input end of the intermediate-pressure cylinder, the output end of the intermediate-pressure cylinder is connected to the input end of the low-pressure cylinder, and the output end of the low-pressure cylinder is connected to the condensing unit.
[0008] Furthermore, the output end of the high-pressure cylinder is also connected to the input end of the boiler.
[0009] Furthermore, the regulating valve assembly includes a medium-pressure cylinder steam inlet heating regulating valve, a first heating regulating valve, and a second heating regulating valve; The intermediate pressure cylinder steam inlet heating regulating valve is installed on the pipeline at the heating end of the intermediate pressure cylinder; Both the first heating regulating valve and the second heating regulating valve are installed on the pipeline between the boiler and the intermediate pressure cylinder steam inlet heating regulating valve and the heat user.
[0010] Preferably, the condensing unit includes a condenser and a condensate pump; The input end of the condenser is connected to the output end of the power unit, the output end of the condenser is connected to the input end of the condensate pump, and the output end of the condensate pump is connected to the input end of the heating and deaeration unit.
[0011] Furthermore, the heating and deaeration unit includes a deaerator, a feed water pump, and a heater unit. The input end of the deaerator is connected to the output end of the condensate pump; the output end of the deaerator is connected to the input end of the feed water pump, and the output end of the feed water pump is connected to the input end of the boiler. The heater units are distributed between the deaerator and the condensate pump, and between the feedwater pump and the boiler.
[0012] Furthermore, the heater unit includes a low-pressure heater unit and a high-pressure heater unit; The low-pressure heater group is located between the deaerator and the condensate pump; the high-pressure heater group is located between the feedwater pump and the boiler.
[0013] Secondly, the present invention also provides an operation method for peak shaving of a steam pipeline network pressure regulating and thermal storage auxiliary coal-fired power unit, based on the above-mentioned operation system for peak shaving of a steam pipeline network pressure regulating and thermal storage auxiliary coal-fired power unit, comprising the following processes: When the cogeneration unit operates independently but does not supply heat to the outside, the first and second heating regulating valves are closed, and the intermediate pressure cylinder steam inlet heating regulating valve is fully open. The main steam generated by the boiler enters the high-pressure cylinder, intermediate pressure cylinder and low-pressure cylinder in sequence to do work. The exhaust steam enters the condenser and is condensed. After being pressurized by the condensate pump, it enters the low-pressure heater group and deaerator to be heated. Then, it is pressurized by the feed water pump and enters the high-pressure heater group to be heated. Finally, it returns to the boiler to complete the thermal cycle. During normal operation, the intermediate pressure cylinder inlet steam heating regulating valve, the first heating regulating valve, and the second heating regulating valve are regulated by pressure regulation, heat storage, and heat release. Part of the boiler outlet hot reheat steam enters the intermediate pressure cylinder through the intermediate pressure cylinder inlet steam heating regulating valve, and part of it is distributed to each heat user through the first heating regulating valve and the second heating regulating valve and then through the industrial steam supply network.
[0014] Preferably, during the heat storage process, by reducing the opening of the intermediate-pressure cylinder steam inlet heating regulating valve and fully opening the heating regulating valve, the steam pressure in the industrial steam supply network is increased until it approaches the network's pressure-bearing capacity value. At this time, adjusting the opening of the heating regulating valve ensures that the steam parameters at the outlet of the heating regulating valve remain at the normal operating conditions, thus meeting the needs of heat users.
[0015] Preferably, during the heat release process, the opening of the heating regulating valve and the heating regulating valve are adjusted to be reduced, while the opening of the intermediate pressure cylinder steam inlet heating regulating valve is increased. This ensures that the steam parameters at the outlet of the heating regulating valve are maintained at the normal operating steam parameters, thereby reducing the steam flow rate of the unit through the heating regulating valve, thus reducing the steam load of the coal-fired power unit and improving the flexibility of power generation.
[0016] Compared with the prior art, the present invention has the following beneficial technical effects: This invention provides an operating system for peak shaving of coal-fired power units by regulating steam network pressure and storing heat. By constructing a complete cogeneration thermal cycle system, it realizes the cascade utilization of steam energy, reduces energy loss, and improves the overall energy utilization efficiency of the unit. At the same time, regulating valve components are set between the boiler and the heating end of the power unit and the heat user. By adjusting the valve opening, the system realizes steam network pressure regulation and heat storage, and steam supply load regulation. This solves the problems of high coupling between heating and power generation loads and poor peak shaving flexibility in traditional coal-fired power units, and lays a system foundation for reducing steam supply load and improving peak shaving efficiency.
[0017] Furthermore, the power-generating unit is further refined into a three-stage series structure of high-pressure cylinder, intermediate-pressure cylinder, and low-pressure cylinder, realizing the cascade power generation of steam energy. The main steam expands and performs work sequentially through the high-pressure cylinder, intermediate-pressure cylinder, and low-pressure cylinder, maximizing the power generation potential of the steam and improving the unit's power generation efficiency. At the same time, the staged power generation structure allows for flexible adjustment of the steam inlet parameters of each cylinder, providing conditions for the subsequent diversion and control of steam inlet and heating in the intermediate-pressure cylinder, adapting to the switching of heating and peak-shaving operating conditions, avoiding unit operation fluctuations caused by operating condition switching, and improving system operation stability.
[0018] Furthermore, by connecting the output end of the high-pressure cylinder to the input end of the boiler, waste heat recovery from the exhaust steam of the high-pressure cylinder is achieved. The exhaust steam after the high-pressure cylinder has done its work is returned to the boiler, which can reuse the residual heat in the exhaust steam, reduce the boiler's fuel consumption, and improve the unit's energy efficiency. At the same time, the returned exhaust steam can participate in the boiler's steam parameter regulation, help stabilize the boiler's operating pressure and temperature, reduce the imbalance of boiler operating parameters caused by load fluctuations, and indirectly improve the system stability during peak shaving.
[0019] Furthermore, by dividing the functions of the intermediate-pressure cylinder steam inlet heating regulating valve, the first heating regulating valve, and the second heating regulating valve, the steam inlet of the intermediate-pressure cylinder and the external steam supply can be controlled separately, realizing the precise allocation of steam in the two paths of power generation and external heating. The hierarchical setting of multiple valves can realize the pressure increase and stable control of the industrial steam supply network through differentiated opening adjustment, providing hardware guarantee for the precise control of network pressure during heat storage and avoiding parameter fluctuations caused by single valve adjustment.
[0020] Furthermore, the condensing unit includes a condenser and a condensate pump, which can efficiently complete the condensation and recovery of exhaust steam. The condenser condenses the exhaust steam from the power unit into water, and the condensate pump pressurizes and delivers the condensate, ensuring the supply of working fluid in the thermodynamic cycle loop and avoiding waste of working fluid. At the same time, the condensation process of the condenser can maintain the vacuum of the unit, improve the working efficiency of the power unit, ensure the stable operation of the cycle system, and stably output condensate with stable pressure, providing stable water inlet conditions for the subsequent heating and deaeration units, and improving the continuity and stability of the thermodynamic cycle.
[0021] Furthermore, the composition and connection of the heating and deaeration unit enable the heating and deaeration of condensate. The deaerator removes oxygen from the condensate, preventing oxidation and corrosion of the boiler and pipelines, and extending the service life of the equipment. The pressurization effect of the feedwater pump can meet the boiler's inlet water pressure requirements, ensuring stable steam production. At the same time, the heater units are distributed before and after the deaerator, which can perform staged heating of the condensate, making full use of the unit's waste heat resources, reducing energy consumption in the heating process, and improving the unit's energy utilization efficiency.
[0022] Furthermore, the heater unit is further subdivided into a low-pressure heater unit and a high-pressure heater unit, realizing the stepped heating of condensate. The low-pressure heater unit initially heats the low-temperature condensate output from the condensate pump, while the high-pressure heater unit heats the water output from the feed water pump. This conforms to the pressure change gradient of the condensate, improving heating efficiency and reducing heat loss. At the same time, the independent setting of the high and low pressure heater units allows for flexible adjustment of the number of heaters in operation according to changes in the unit's peak load, avoiding energy waste caused by full-load heating and improving energy-saving effects during peak load regulation.
[0023] This invention also provides an operation method for peak shaving of coal-fired power units using steam network pressure regulation and thermal storage. Based on two operating conditions—pure power generation without heat supply and normal cogeneration—it can achieve flexible switching of operating conditions. According to the peak shaving needs of the power grid and the needs of heat users, it can quickly switch operating modes, solving the problem of slow response when switching operating conditions of traditional units. At the same time, under normal operating conditions, through the diversion and regulation of hot resteam at the boiler outlet, it can achieve parallel operation of power generation and external heat supply, providing a reference logic for valve regulation in the subsequent heat storage and heat release processes, and ensuring the stability of heat supply parameters during peak shaving.
[0024] Furthermore, the specific operation method of the heat storage process can efficiently realize heat storage in the steam pipeline network. By reducing the opening of the steam supply regulating valve of the medium-pressure cylinder and fully opening the first heating regulating valve, the pressure of the industrial steam supply pipeline network is increased to close to the pressure bearing capacity, maximizing the use of the energy storage space of the pipeline network and increasing the heat storage capacity. At the same time, during the heat storage and pressurization process, by adjusting the opening of the second heating regulating valve, the outlet steam parameters are kept stable, avoiding the steam consumption parameters of heat users from exceeding the standard due to the pressurization of the pipeline network, achieving the goal of heat storage without affecting the heating supply, and improving the reliability of system operation.
[0025] Furthermore, the specific operating method of the heat release process can directly reduce the steam supply load of the unit. By adjusting the opening of the first and second heating regulating valves in a coordinated manner, the external steam supply flow is reduced, thereby directly reducing the steam supply load of the coal-fired power unit. At the same time, the opening of the intermediate pressure cylinder inlet steam heating regulating valve is increased to ensure the steam intake of the intermediate pressure cylinder and improve the unit's power generation. Under the premise of maintaining stable steam parameters at the outlet of the second heating regulating valve and meeting the needs of heat users, the power generation flexibility of the coal-fired power unit is effectively improved, and the peak-shaving efficiency is improved. Attached Figure Description
[0026] Figure 1 This is a structural diagram of the operating system of the steam pipeline pressure regulation and thermal storage auxiliary coal-fired power unit for peak shaving in an embodiment of the present invention; In the diagram: 1. Boiler; 2. High-pressure cylinder; 3. Medium-pressure cylinder; 4. Low-pressure cylinder; 5. Condenser; 6. Condensate pump; 7. Low-pressure heater group; 8. Deaerator; 9. Feed water pump; 10. High-pressure heater group; 11. Medium-pressure cylinder inlet heating regulating valve; 12. First heating regulating valve; 13. Second heating regulating valve. Detailed Implementation
[0027] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.
[0028] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0029] The purpose of this invention is to provide an operating system and method for peak shaving of coal-fired power units with steam network pressure regulation and thermal storage, so as to solve the technical problem of how to reduce the steam supply load of coal-fired power units and improve the operating efficiency of peak shaving of coal-fired power units with steam network pressure regulation and thermal storage.
[0030] The present invention will now be described in further detail with reference to the accompanying drawings: Example 1 See Figure 1 In one embodiment of the present invention, an operating system for peak shaving of a steam pipeline pressure regulating and thermal storage auxiliary coal-fired power unit is provided, including a boiler 1, a regulating valve assembly, a power unit, a condensing unit, and a heating and deoxygenating unit; the output end of the boiler 1 is connected to the input end of the power unit, the output end of the power unit is connected to the input end of the condensing unit, the output end of the condensing unit is connected to the input end of the heating and deoxygenating unit, and the output end of the heating and deoxygenating unit is connected to the input end of the boiler, forming a thermal circulation loop; the heating ends of the boiler 1 and the power unit are connected to heat users through pipelines, and the regulating valve assembly is installed on the pipeline between the heating ends of the boiler 1 and the power unit and the heat users, for regulating heat through the regulating valve assembly.
[0031] Specifically, the working unit includes a high-pressure cylinder 2, a medium-pressure cylinder 3, and a low-pressure cylinder 4; the output end of the boiler 1 is connected to the input end of the high-pressure cylinder 2, the output end of the high-pressure cylinder 2 is connected to the input end of the medium-pressure cylinder 3, the output end of the medium-pressure cylinder 3 is connected to the input end of the low-pressure cylinder 4, and the output end of the low-pressure cylinder 4 is connected to the condensing unit.
[0032] In this embodiment, the power unit is designed as a three-stage series structure consisting of a high-pressure cylinder, a medium-pressure cylinder, and a low-pressure cylinder. This allows the high-temperature and high-pressure main steam to expand and perform work sequentially in the three cylinders, maximizing the steam's work potential and improving the unit's power generation efficiency. At the same time, the medium-pressure cylinder serves as a key diversion node for heating and power generation, providing a structural basis for the precise control of the steam intake and supply in the subsequent medium-pressure cylinder, and adapting to the operating requirements under different working conditions.
[0033] The output end of the high-pressure cylinder 2 is also connected to the input end of the boiler 1.
[0034] In this embodiment, based on the requirements of waste heat recovery and system parameter stability, the output end of the high-pressure cylinder is connected to the input end of the boiler, so that the waste heat carried by the exhaust steam after the high-pressure cylinder performs work flows back to the boiler, reducing boiler fuel consumption and improving energy utilization efficiency. At the same time, the returned exhaust steam can participate in the adjustment of boiler steam inlet parameters, alleviating the boiler pressure and temperature imbalance caused by load fluctuations and enhancing the stability of system operation.
[0035] The regulating valve assembly includes a medium-pressure cylinder steam inlet heating regulating valve 11, a first heating regulating valve 12, and a second heating regulating valve 13; the medium-pressure cylinder steam inlet heating regulating valve 11 is installed on the pipeline at the heating end of the medium-pressure cylinder 3; the first heating regulating valve 12 and the second heating regulating valve 13 are both installed on the pipeline between the boiler 1 and the medium-pressure cylinder steam inlet heating regulating valve 11 and the heat user.
[0036] In this embodiment, a multi-valve hierarchical control approach is adopted. A steam inlet heating regulating valve for the intermediate pressure cylinder is set to control the steam inlet volume of the intermediate pressure cylinder, which is directly related to the unit's power generation load. A first heating regulating valve is set to regulate the pressure of the industrial steam supply network, and a second heating regulating valve is set to maintain the steam parameters at the heat user end. Through the coordinated operation of the three valves, precise control of steam flow and pressure is achieved, providing a reliable valve regulation scheme for the heat storage and heat release process.
[0037] Specifically, the condensing unit includes a condenser 5 and a condensate pump 6; the input end of the condenser 5 is connected to the output end of the work unit, the output end of the condenser 5 is connected to the input end of the condensate pump 6, and the output end of the condensate pump 6 is connected to the input end of the heating and deaeration unit.
[0038] In this embodiment, a deaerator is installed to remove oxygen from the condensate, preventing oxidation and corrosion of the boiler and pipelines and extending the service life of the equipment. A feedwater pump is installed to provide sufficient pressure for the boiler feedwater, ensuring stable steam production. At the same time, heater units are distributed before and after the deaerator, using the unit's waste heat to perform staged heating of the condensate, which conforms to the pressure change pattern of the condensate, improving heating efficiency and reducing energy consumption.
[0039] The heating and deaeration unit includes a deaerator 8, a feedwater pump 9, and a heater group unit. The input end of the deaerator 8 is connected to the output end of the condensate pump 6. The output end of the deaerator 8 is connected to the input end of the feedwater pump 9, and the output end of the feedwater pump 9 is connected to the input end of the boiler 1. The heater group unit is distributed between the deaerator 8 and the condensate pump 6, and between the feedwater pump 9 and the boiler 1.
[0040] In this embodiment, the heater unit is subdivided into a low-pressure heater unit and a high-pressure heater unit. The low-pressure heater unit is adapted to the low-pressure condensate output by the condensate pump for initial heating, while the high-pressure heater unit is adapted to the high-pressure feedwater output by the feedwater pump for deep heating. This conforms to the pressure gradient changes of the working fluid in the thermodynamic cycle, improving heat recovery efficiency. At the same time, the number of heaters can be flexibly adjusted according to the changes in the unit's peak load to avoid energy waste caused by full-load heating.
[0041] The heater unit includes a low-pressure heater group 7 and a high-pressure heater group 10; the low-pressure heater group 7 is located between the deaerator 8 and the condensate pump 6; the high-pressure heater group 10 is located between the feedwater pump 9 and the boiler 1.
[0042] In summary, the steam network pressure regulation and thermal storage auxiliary peak-shaving operation system provided in this embodiment constructs a complete cogeneration thermal cycle system, realizes the cascade utilization of steam energy, reduces energy loss, and improves the overall energy utilization efficiency of the unit. At the same time, regulating valve components are set between the boiler and the heating end of the power unit and the heat user. By adjusting the valve opening, steam network pressure regulation and thermal storage and steam supply load regulation are realized. This solves the problems of high coupling between heating and power generation loads and poor peak-shaving flexibility in traditional coal-fired power units, laying a system foundation for reducing steam supply load and improving peak-shaving efficiency.
[0043] Example 2 This embodiment also provides an operation method for peak shaving of a steam pipeline network pressure regulating and thermal storage auxiliary coal-fired power unit. Based on the above-described operation system for peak shaving of a steam pipeline network pressure regulating and thermal storage auxiliary coal-fired power unit, the method includes the following process: When the cogeneration unit operates independently but does not supply heat to the outside, the first heating regulating valve 12 and the second heating regulating valve 13 are closed, and the intermediate pressure cylinder steam inlet heating regulating valve 11 is fully open. The main steam generated by boiler 1 enters the high pressure cylinder 2, intermediate pressure cylinder 3 and low pressure cylinder 4 in sequence to do work. The exhaust steam enters the condenser 5 for condensation and is then pressurized by the condensate pump 6 and enters the low pressure heater group 7 and deaerator 8 for heating. Then, it is pressurized by the feed water pump 9 and enters the high pressure heater group 10 for heating before returning to boiler 1 to complete the thermal cycle. During normal operation, the intermediate pressure cylinder steam inlet heating regulating valve 11 and heating regulating valves 12 and 13 are regulated by pressure regulation, heat storage and heat release. Part of the hot reheat steam from the boiler 1 outlet enters the intermediate pressure cylinder through the intermediate pressure cylinder steam inlet heating regulating valve 11, and part of it is distributed to each heat user through the first heating regulating valve 12 and the second heating regulating valve 13 and then through the industrial steam supply network.
[0044] Specifically, during the heat storage process, by reducing the opening of the intermediate pressure cylinder steam inlet heating regulating valve 11 and fully opening the heating regulating valve 12, the steam pressure in the industrial steam supply network is increased until it approaches the network's pressure-bearing capacity. At this time, the opening of the heating regulating valve 13 is adjusted so that the steam parameters at the outlet of the heating regulating valve 13 remain at the normal operating conditions to meet the needs of heat users.
[0045] During periods of high renewable energy generation, combined heat and power (CHP) units need to reduce their power output; conversely, during periods of low renewable energy output, CHP units need to increase their power output. In these situations, industrial steam network energy storage is required to participate in regulation and improve the flexibility of coal-fired power generation. During this phase, the industrial steam network shares some of the industrial steam load that would otherwise be borne by coal-fired power units, effectively reducing the steam load on the coal-fired power units.
[0046] In this embodiment, the pressure-bearing capacity of the industrial steam supply network is used to store steam energy. By reducing the opening of the intermediate-pressure cylinder inlet steam heating regulating valve and fully opening the first heating regulating valve, the amount of steam entering the intermediate-pressure cylinder is reduced, while the amount of steam entering the industrial steam supply network is increased. This raises the network pressure to near the pressure-bearing capacity value, thereby storing steam energy. At the same time, the opening of the second heating regulating valve is adjusted to maintain stable steam parameters at its outlet, ensuring that the steam demand of heat users is not affected during the heat storage process, thus resolving the contradiction between heat storage and heating.
[0047] Specifically, during the heat release process, the opening of the heating regulating valve 13 and the heating regulating valve 12 are adjusted to be reduced, while the opening of the intermediate pressure cylinder steam inlet heating regulating valve 11 is increased. This ensures that the steam parameters at the outlet of the heating regulating valve 13 are maintained at the normal operating steam parameters, thereby reducing the steam flow rate of the unit through the heating regulating valve 12, thus reducing the steam load of the coal-fired power unit and improving the flexibility of power generation.
[0048] In this embodiment, based on the peak-shaving concept of shifting heating load to power generation load, the opening of the first and second heating regulating valves is reduced to decrease the external steam flow and lower the unit's steam load. At the same time, the opening of the intermediate-pressure cylinder inlet heating regulating valve is increased to increase the amount of steam entering the intermediate-pressure cylinder and improve the unit's power generation. Under the premise of maintaining stable steam parameters at the outlet of the second heating regulating valve and meeting the needs of heat users, the shift from heating load to power generation load is achieved, improving the power generation flexibility of the coal-fired power unit and achieving the goal of peak shaving and efficiency improvement.
[0049] In this embodiment, the peak-shaving capacity is improved by using a steam pipeline network pressure regulation and thermal storage auxiliary operation method for coal-fired power units. The specific process is as follows: Step 1: Clarify the impact of steam supply from coal-fired power units on flexible power generation capacity. 1) The rated output of the boiler was determined by combining on-site testing and numerical modeling calculations. D max Under these conditions, the unit's hot re-extraction steam flow rate Q and generator unit power N Relationship: N = f 1( D max , Q ).
[0050] In the formula, D max , Q and N The units are t / h, t / h and MW respectively.
[0051] Through a combination of on-site testing and numerical modeling calculations, the minimum boiler output was determined under the condition of hot re-extraction steam heating mode, meeting the industrial steam supply parameters (at which point both the second heating regulating valve 13 and the first heating regulating valve 12 are fully open). D min Under these conditions, the steam extraction flow rate of hot re-extraction steam Q and generator unit power N Relationship: N = f 2( D min , Q ).
[0052] 3) By combining on-site testing and numerical modeling calculations, the minimum boiler output under the condition of pure condensing operation and minimum stable combustion load was determined. D 0, minimum generating capacity of the unit N min and boiler output D Relation of 0: Nmin = f 3( D 0).
[0053] 4) Boiler minimum output D min and boiler rated output D max Divide the space between the two halves into five equal parts; at this point, the boiler outputs are respectively... D 1= D min +( D max - D min ) / 6、 D 2= D min +2×( D max - D min ) / 6、 D 3= D min +3×( D max - D min ) / 6、 D 4= D min +4×( D max - D min ) / 6、 D 5= D min +5×( D max - D min ) / 6.
[0054] Under the above five boiler output conditions, by adjusting the intermediate-pressure cylinder steam inlet heating regulating valve 11 to the minimum allowable value (provided by the turbine manufacturer through thermal calculation), the corresponding maximum hot reheat steam pressure is... P 1. P 2. P 3. P 4 and P 5. At this time, the first heating regulating valve 12 is fully open.
[0055] 5) Based on clause 4), the maximum value of the reheat pressure as a function of boiler output is obtained through fitting. D Relationship: P rh = f 4( D ).
[0056] Step 2: Clarify the relationship between pipeline pressure regulation and energy storage and steam pressure difference. 1) Determine the required steam parameters for the heat user side ( P u (Unit: MPa) T u (unit: °C) and flow rate ( Q u (Unit: t / h)
[0057] 2) Assuming the pipeline network does not store energy at this time, and the pressure within the steam pipeline network is equal to the steam pressure required by the heat user side, calculate the specific volume of steam within the steam pipeline network based on the thermodynamic properties of steam. v 0 (unit: m) 3 ( / kg) and density r 0 (unit: kg / m³) 3 Based on the length of the steam pipeline network. L (Unit: meters), inner diameter D e (Unit: meters) The total volume of the steam pipe network can be calculated. V (Unit: cubic meters), calculate using the following formula: V =3.14× D e × D e × L / 4 Then calculate the total mass of steam in the steam pipeline network. m 0= r × V。
[0058] 3) When the pipeline network enters the energy storage stage, the pressure in the steam pipeline network increases, and the parameters are basically equivalent to the reheat steam pressure. P rh The temperature is equivalent to the hot resteam temperature. T rh Based on the thermodynamic properties of steam, the specific volume of steam in the steam pipeline network is calculated. v 1 (unit: m) 3 ( / kg) and density r 1 (unit: kg / m³) 3 According to the length of the steam pipeline network. L (Unit: meters), inner diameter D e (Unit: meters), the total volume V (unit: cubic meters) of the steam pipe network can be calculated using the following formula: V = 3.14 × D e × D e × L / 4 Then calculate the total mass of steam in the steam pipeline network.m 1= r 1× V。
[0059] 4) Comparing 2) and 3), it can be seen that through steam network pressure regulation operations, the steam quality in the industrial steam supply network is changed from... m 0 upgraded to m 1. Of course, with P rh - P u The greater the difference, the greater the difference in steam density, and the greater the steam energy stored in the steam pipeline network.
[0060] Step 3: Clarify the relationship between pipeline pressure regulation and energy storage and the flexible power generation capability of coal-fired power units during the energy release phase. A: If coal-fired power units require deep peak shaving 1) First, close the first heating regulating valve 12, fully open the intermediate-pressure cylinder steam inlet heating regulating valve 11, and adjust the opening of the second heating regulating valve 13 to first use the steam in the steam pipeline network for external heating. At this time, the minimum power generation output of the coal-fired power unit is calculated according to... N min = f 3( D 0) Confirmed. The steam pressure in the steam pipeline network then gradually decreases.
[0061] 2) The steam pressure in the steam pipeline network must equal the steam pressure required by the heat user. P u At this time, heating regulating valve 12 needs to be opened continuously, and the hot steam extracted from the coal-fired power unit enters the steam pipeline network, thereby supplying steam to heat users. At this time, the minimum power generation output of the coal-fired power unit is calculated according to... N = f 2( D min , Q )Sure.
[0062] 3) During the deep peak shaving stage, the contribution of the steam pipeline pressure regulating energy storage system to the peak shaving capacity of the coal-fired power unit is the difference between 2) and 1), and the duration is the time from when the heating regulating valve 12 in 1) is closed to when the first heating regulating valve 12 is opened in 2).
[0063] B: If coal-fired power units need to implement peak shaving 1) First, close the first heating regulating valve 12, fully open the intermediate-pressure cylinder steam inlet heating regulating valve 11, and adjust the opening of the second heating regulating valve 13 to first use the steam in the steam pipeline network for external heating. At this time, the maximum power generation output of the coal-fired power unit is calculated according to... N = f 1( D max , Q ) Confirmed, at this time,Q =0. The steam pressure in the steam pipeline network then gradually decreases.
[0064] 2) The steam pressure in the steam pipeline network must equal the steam pressure required by the heat user. P u At this time, the first heating regulating valve 12 needs to be opened to allow the hot steam extracted from the coal-fired power unit to enter the steam pipeline network and then supply steam to the heat users. At this time, the maximum power generation output of the coal-fired power unit is calculated according to... N = f 1( D max , Q ) Confirmed, at this time, Q Steam flow rate to meet the steam demand of external industries.
[0065] 3) During the peak stage, the contribution of the steam pipeline pressure regulating and energy storage system to the peak-shaving capacity of the coal-fired power unit is the difference between 1) and 2), and the duration is the time from when the heating regulating valve 12 in 1) is closed to when the first heating regulating valve 12 is opened in 2).
[0066] For example, a 300MW subcritical unit uses hot re-extraction to supply industrial steam. The user-side requirements are 1MPa and 100t / h. The steam pipeline from the power plant to the user is 30km long with a diameter of DN700 and a pressure-bearing capacity of 4MPa. After accounting for pipeline pressure loss, the steam pressure at the hot re-extraction point of the coal-fired power unit is 1.6MPa. The minimum power generation capacity to meet the steam pressure requirements is 50%Pe. Under pure condensing mode, the minimum power generation capacity is 25%Pe. The maximum steam pressure at the hot re-extraction point of the coal-fired power unit is 3.5MPa.
[0067] Before implementing the steam network pressure regulation and energy storage operation, the average pressure of the steam network was taken as the average of 1 and 1.6, the steam density was 3.59 kg / m3, and the steam mass of the entire steam network was 41.5 tons.
[0068] After implementing the steam pipeline pressure regulation and energy storage operation, the average pressure of the steam pipeline is taken as the average of 3.5 and 2.9, the steam density is 8.87 kg / m3, and the steam mass of the entire steam pipeline is 102.3 tons.
[0069] Through steam pressure regulation, the pipeline network can store 60.8 tons of energy.
[0070] In terms of enhancing deep peak shaving capabilities, it can improve peak shaving capacity by 25% Pe and 75MW, with a duration of approximately 0.6 hours.
[0071] In terms of boosting peak capacity, it can increase peak shaving capacity by 60.8 × 0.33 = 20 MW, lasting for about 0.6 hours.
[0072] This embodiment uses the adjustment of steam pressure within the industrial steam pipeline network, in conjunction with the industrial steam supply regulation method of coal-fired power units, to improve the deep peak-shaving capacity and peak power generation capacity of coal-fired power units. The method proposed in this invention is advanced, scientific, and easy to operate, and can provide a technical reference for improving the flexible power generation capacity of coal-fired power units undertaking industrial steam supply.
[0073] In summary, this embodiment also provides an operation method for peak shaving of coal-fired power units using steam network pressure regulation and thermal storage. Based on two operating conditions—pure power generation without heat supply and normal cogeneration—it can achieve flexible switching of operating conditions. According to the peak shaving needs of the power grid and the needs of heat users, it can quickly switch operating modes, solving the problem of slow response when switching operating conditions of traditional units. At the same time, under normal operating conditions, through the diversion and regulation of hot resteam at the boiler outlet, it can achieve parallel operation of power generation and external heat supply, providing a reference logic for valve regulation in the subsequent heat storage and heat release processes, and ensuring the stability of heat supply parameters during peak shaving.
[0074] 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. An operating system for peak shaving of a coal-fired power unit using steam pipeline pressure regulation and thermal storage, characterized in that, Includes boiler (1), regulating valve assembly, power unit, condensing unit and heating and deaeration unit; The output end of the boiler (1) is connected to the input end of the power unit, the output end of the power unit is connected to the input end of the condensing unit, the output end of the condensing unit is connected to the input end of the heating and deoxygenating unit, and the output end of the heating and deoxygenating unit is connected to the input end of the boiler, forming a thermal circulation loop. The heating end of the boiler (1) and the working unit is connected to the heat user through a pipeline. The regulating valve assembly is installed on the pipeline between the heating end of the boiler (1) and the working unit and the heat user, and is used to regulate the heat through the regulating valve assembly.
2. The operating system for peak shaving of a steam pipeline pressure regulating and thermal storage auxiliary coal-fired power unit according to claim 1, characterized in that, The working unit includes a high-pressure cylinder (2), a medium-pressure cylinder (3), and a low-pressure cylinder (4); The output end of the boiler (1) is connected to the input end of the high-pressure cylinder (2), the output end of the high-pressure cylinder (2) is connected to the input end of the medium-pressure cylinder (3), the output end of the medium-pressure cylinder (3) is connected to the input end of the low-pressure cylinder (4), and the output end of the low-pressure cylinder (4) is connected to the condensing unit.
3. The operating system for peak shaving of a steam pipeline pressure regulating and thermal storage auxiliary coal-fired power unit according to claim 2, characterized in that, The output end of the high-pressure cylinder (2) is also connected to the input end of the boiler (1).
4. The operating system for peak shaving of a steam pipeline pressure regulating and thermal storage auxiliary coal-fired power unit according to claim 2, characterized in that, The regulating valve assembly includes a medium-pressure cylinder steam inlet heating regulating valve (11), a first heating regulating valve (12), and a second heating regulating valve (13). The steam inlet heating regulating valve (11) of the intermediate pressure cylinder is installed on the pipeline at the heating end of the intermediate pressure cylinder (3); The first heating regulating valve (12) and the second heating regulating valve (13) are both installed on the pipeline between the boiler (1) and the intermediate pressure cylinder steam inlet heating regulating valve (11) and the heat user.
5. The operating system for peak shaving of a steam pipeline pressure regulating and thermal storage auxiliary coal-fired power unit according to claim 1, characterized in that, The condensing unit includes a condenser (5) and a condensate pump (6); The input end of the condenser (5) is connected to the output end of the power unit, the output end of the condenser (5) is connected to the input end of the condensate pump (6), and the output end of the condensate pump (6) is connected to the input end of the heating and deoxygenation unit.
6. The operating system for peak shaving of a steam pipeline pressure regulating and thermal storage auxiliary coal-fired power unit according to claim 5, characterized in that, The heating and deoxygenation unit includes a deaerator (8), a water supply pump (9), and a heater unit; The input end of the deaerator (8) is connected to the output end of the condensate pump (6); the output end of the deaerator (8) is connected to the input end of the feed water pump (9), and the output end of the feed water pump (9) is connected to the input end of the boiler (1). The heater units are distributed between the deaerator (8) and the condensate pump (6), and between the feed water pump (9) and the boiler (1).
7. The operating system for peak shaving of a steam pipeline pressure regulating and thermal storage auxiliary coal-fired power unit according to claim 6, characterized in that, The heater unit includes a low-pressure heater group (7) and a high-pressure heater group (10). The low-pressure heater group (7) is located between the deaerator (8) and the condensate pump (6); the high-pressure heater group (10) is located between the feed water pump (9) and the boiler (1).
8. A method for operating a steam pipeline network pressure regulating and thermal storage auxiliary coal-fired power unit for peak shaving, characterized in that, An operating system for peak shaving of a steam pipeline pressure regulating and thermal storage auxiliary coal-fired power unit according to any one of claims 1-7 includes the following processes: When the cogeneration unit operates independently but does not supply heat to the outside, the first heating regulating valve (12) and the second heating regulating valve (13) are closed, and the intermediate pressure cylinder steam inlet heating regulating valve (11) is fully open. The main steam generated by the boiler (1) enters the high pressure cylinder (2), the intermediate pressure cylinder (3) and the low pressure cylinder (4) in sequence to do work. The exhaust steam enters the condenser (5) and is condensed. After being pressurized by the condensate pump (6), it enters the low pressure heater group (7) and the deaerator (8) to be heated. Then, it is pressurized by the feed water pump (9) and enters the high pressure heater group (10) to be heated and then returned to the boiler (1) to complete the thermal cycle. During normal operation, the intermediate pressure cylinder steam inlet heating regulating valve (11), the first heating regulating valve (12), and the second heating regulating valve (13) are regulated by pressure regulation, heat storage, and heat release. Part of the hot reheat steam from the boiler (1) enters the intermediate pressure cylinder through the intermediate pressure cylinder steam inlet heating regulating valve (11), and part of it is distributed to each heat user through the first heating regulating valve (12) and the second heating regulating valve (13) via the industrial steam supply network.
9. The method for operating a steam pipeline pressure regulating and thermal storage auxiliary coal-fired power unit for peak shaving according to claim 8, characterized in that, During the heat storage process, by reducing the opening of the intermediate pressure cylinder steam inlet heating regulating valve (11) and opening the heating regulating valve (12) to full opening, the steam pressure in the industrial steam supply network is increased until it approaches the network's pressure-bearing capacity value. At this time, the opening of the heating regulating valve (13) is adjusted so that the steam parameters at the outlet of the heating regulating valve (13) remain at the normal operating conditions, in order to meet the needs of heat users.
10. The operation method for peak shaving of a steam pipeline network pressure regulating and thermal storage auxiliary coal-fired power unit according to claim 8, characterized in that, During the heat release process, the opening of the heating regulating valve (13) and the heating regulating valve (12) are adjusted to be reduced, while the opening of the intermediate pressure cylinder steam inlet heating regulating valve (11) is increased. This ensures that the steam parameters at the outlet of the heating regulating valve (13) are maintained at the normal operating steam parameters, thereby reducing the steam flow rate of the unit through the heating regulating valve (12), thus reducing the steam load of the coal-fired power unit and improving the flexibility of power generation.