A multi-mode steam supply system for a combined heat and power unit
By adjusting steam parameters under different load conditions through a multi-mode steam supply system, the problem that traditional steam supply methods cannot meet the needs of heat users has been solved, achieving stable steam supply and energy conservation and emission reduction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- GUONENG HUDIAN (SHANGHAI) ENGINEERING TECHNOLOGY CO LTD
- Filing Date
- 2025-06-12
- Publication Date
- 2026-06-09
AI Technical Summary
Traditional steam supply methods cannot reliably meet the steam parameter requirements of heat users when the boiler is under high or low load, resulting in energy waste and unstable steam supply, which affects the unit's deep peak shaving capability.
A multi-mode steam supply system is adopted, which sets different steam extraction points and steam supply paths under different load conditions, and uses equipment such as desuperheaters, steam booster pumps and pressure matchers to adjust steam parameters to meet the needs of heat users.
It has achieved a stable supply of steam parameters to heat users under 0%-100% load conditions, saving energy and improving the deep peak-shaving capability of the unit and the applicability and reliability of the steam supply system.
Smart Images
Figure CN224340221U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of power plant steam supply equipment technology, specifically a multi-mode steam supply system for cogeneration units. Background Technology
[0002] With the increasing maturity of industrialization and urban infrastructure development across China, and the arrival of a second peak in renovation and construction, the demand for technological upgrades in steam, heat, and ventilation systems for power plants is growing. At the power grid level, the installed capacity of new energy power generation nationwide is repeatedly reaching new highs, placing new demands on the deep peak-shaving capabilities of power plants. Facing deep peak-shaving, the primary issue for combined heat and power (CHP) units is how to ensure the steam supply parameters required by heat users and the economic viability of the unit's steam supply. Taking a 2×300MW unit in a southern thermal power plant as an example, the unit underwent steam supply upgrades in earlier years, with a high- and medium-pressure steam supply demand of 350T / h. Due to the high steam parameter requirements of limited heat users, the current electrical load of the unit can only be reduced to 50%, while a typical pure condensing unit (only involved in power generation) can reduce the electrical load to 30%. With relevant technological upgrades, such as boiler-side reheater upgrades and igniter replacements, the unit's deep peak-shaving load can be reduced to as low as 20% or even 15%. Therefore, whether or not the unit has a steam supply significantly affects its deep peak-shaving capability. If this patented technology is introduced, the deep peak-shaving capacity of the unit can be increased, and the steam parameter requirements of its heat users can be guaranteed. For power grids in various regions, it can greatly absorb new energy power generation and has very good economic benefits.
[0003] Traditional thermal power units use extraction steam supply methods, selecting a suitable steam source extraction point based on the steam parameters required by heat users. Some solutions add desuperheating and pressure reducing devices to the pipeline, which can reduce steam parameters by using pressure reducing valves and adding desuperheating water when the steam source parameters are higher than the heat user's required parameters.
[0004] Traditional single-source steam extraction point steam supply methods suffer from significant energy waste when the boiler is under high load. This is because the steam source parameters are far higher than the heat user's requirements, necessitating the addition of excessive desuperheating water and resulting in a small pressure-reducing valve opening. Conversely, under low load conditions, the steam source parameters are lower than the heat user's requirements, and there is no suitable steam source to supplement them, failing to meet the heat user's needs. Overall, traditional steam supply methods are heavily dependent on the boiler load status and, in the current environment of deep peak shaving, rapid load increases, and peak demand in the electricity market, are neither stable nor environmentally friendly. Utility Model Content
[0005] The purpose of this utility model is to provide a multi-mode steam supply system for cogeneration units that improves the deep peak-shaving capability of the unit, ensures the steam parameter requirements of heat users, achieves environmental protection and energy saving, and enhances the applicability and reliability of the steam supply system.
[0006] This utility model is implemented as follows:
[0007] A multi-mode steam supply system for a combined heat and power (CHP) unit includes a superheater that outputs main steam, the superheater being connected to a third regulating path, a high-pressure cylinder being connected to the superheater, the high-pressure cylinder being connected to a reheater that outputs hot-section steam, the reheater being connected to a first regulating path, a second regulating path, and a third regulating path, the reheater being connected to an intermediate regulating valve, the intermediate regulating valve being connected to an intermediate-pressure cylinder, the first regulating path, the second regulating path, and the third regulating path being connected to a steam header, the steam header outputting steam to heat users.
[0008] The multi-mode steam supply device for cogeneration units of this utility model divides the boiler load of the unit into high load, medium load and low load states based on the threshold range of the difference between the steam parameters of the reheater hot section and the heat user demand parameters, and sets different steam extraction points and corresponding steam supply paths for different load states.
[0009] When the unit boiler is under high load (60%-100%), the difference between the steam parameters in the reheater hot section and the heat user's demand parameters is greater than or equal to zero, and the extraction steam point is set to the reheater hot section steam. At this time, the steam is adjusted through a first regulating path, which includes a steam pressure and temperature regulating device connected to the reheater at its input end. This steam pressure and temperature regulating device is preferably a desuperheater and pressure reducer. After the steam enters the desuperheater and pressure reducer, the steam pressure is regulated by the regulating valve within the device. Simultaneously, atomized desuperheating water is injected into the steam pipeline to regulate the steam temperature. After the steam is adjusted to meet the heat user's demand parameters, it is supplied to the heat user through the steam header, while other steam supply paths are shut down.
[0010] When the boiler is under medium load (40%-60%), the difference between the reheater hot section steam parameters and the heat user demand parameters is less than zero and greater than or equal to a set threshold, such as -1 MPa. The extraction steam point is also set to the reheater hot section steam. The steam is adjusted via a second regulation path, which includes a steam booster pump connected to the reheater at its input end. The steam booster pump includes a booster compressor and a drive unit. The output end of the steam booster pump is connected to a steam temperature regulating device, preferably a desuperheater. After the steam enters the steam booster pump, the booster pump increases the steam pressure to the heat user demand parameters. Then, the steam enters the desuperheater, which injects atomized desuperheating water into the steam pipeline to reduce the steam temperature to the heat user demand parameters. Finally, the steam is supplied to the heat user through the steam header, while other steam supply paths are shut down.
[0011] When the unit boiler is under low load (15%-40%), the difference between the reheater hot section steam parameters and the heat user demand parameters is less than a set threshold, such as -1MPa. The extraction steam points are set for the unit's main steam and reheater hot section steam. The two steam streams are adjusted through a third regulating path. This third regulating path includes a steam pressure matching regulating device with its input end connected to the superheater, preferably a pressure matcher. The other input end of the pressure matcher is connected to the reheater, and the output end of the pressure matcher is connected to a second steam temperature regulating device, preferably a desuperheater. After the main steam and reheater hot section steam enter the pressure matcher, the pressure matcher adjusts the main steam to inject the reheater hot section steam to the heat user demand pressure value. Then, atomized desuperheating water is injected into the steam pipeline through the desuperheater to reduce the steam temperature to the heat user demand parameters. Finally, the steam is supplied to the heat user through the steam header, while other steam supply paths are shut down.
[0012] When the boiler is in the start-up / shutdown state (0%-15%), the flame combustion inside the boiler is unstable and outside the normal operating load range, so the unit cannot generate stable steam.
[0013] In addition, control valves are connected to the steam header at each of the first, second, and third regulating paths to precisely control the direction and flow rate of steam, ensuring the safe and stable operation of the steam supply system. The main function of the steam header is to collect, mix, and distribute steam, ensuring uniform steam distribution and output.
[0014] Compared with the prior art, the beneficial effects of this utility model are:
[0015] This invention addresses the steam parameters of a combined heat and power (CHP) unit under various operating conditions from 0% to 100% load, taking into account multiple influencing factors such as the power plant's external steam and heat supply needs and the unit's overall coal consumption. Through flexible combinations of equipment such as pressure matching devices, steam booster pumps, and desuperheaters and pressure reducers, it achieves safe, stable, and uninterrupted steam parameters for heat users under full load conditions, conserving every bit of energy output from the unit to meet energy conservation and carbon reduction requirements. Attached Figure Description
[0016] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.
[0017] Figure 1 This is a schematic diagram of the thermal system flow of this utility model;
[0018] Figure 2 This is the load-steam pressure curve of this utility model. Detailed Implementation
[0019] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model. Therefore, the following detailed description of the embodiments of this utility model provided in the accompanying drawings is not intended to limit the scope of the claimed utility model, but merely represents selected embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.
[0020] Please see Figure 1 and Figure 2 A multi-mode steam supply system for a combined heat and power (CHP) unit includes a superheater that outputs main steam, the superheater being connected to a third regulating path, a high-pressure cylinder being connected to the superheater, a reheater that outputs hot-section steam being connected to the high-pressure cylinder, the reheater being connected to a first regulating path, a second regulating path, and a third regulating path, the reheater being connected to an intermediate regulating valve, the intermediate regulating valve being connected to an intermediate-pressure cylinder, the first regulating path, the second regulating path, and the third regulating path being connected to a steam header, the steam header outputting steam to heat users;
[0021] The first adjustment path is used to reduce the temperature and pressure of the hot section steam to the heat user's required parameters; the second adjustment path is used to increase the pressure of the hot section steam to the heat user's required parameters while reducing the temperature to the heat user's required parameters; the third adjustment path is used to reduce the temperature of the main steam and the hot section steam to the heat user's required parameters while mixing and matching the pressure of the main steam and the hot section steam to the heat user's required parameters.
[0022] Each of the first, second, and third regulating paths is connected to the steam header with a control valve for controlling the on / off state of the corresponding path.
[0023] The first regulation path includes a steam pressure and temperature regulating device whose input end is connected to the reheater, and whose output end is connected to the steam header.
[0024] The steam pressure and temperature regulating device is a desuperheater and pressure reducer.
[0025] The second regulation path includes a steam booster pump whose input end is connected to the reheater, and a steam temperature regulating device 1 whose output end is connected to the steam header.
[0026] The steam booster pump includes a booster and a drive unit.
[0027] One of the steam temperature regulating devices is a desuperheater.
[0028] The third regulation path includes a steam pressure matching regulation device with an input end connected to the superheater, another input end of the steam pressure matching regulation device connected to the reheater, and an output end of the steam pressure matching regulation device connected to a second steam temperature regulation device, the output end of the second steam temperature regulation device connected to the steam header.
[0029] The steam pressure matching and regulating device is a pressure matcher.
[0030] The second steam temperature regulating device is a desuperheater.
[0031] In practical applications, please refer to Figure 1 and Figure 2 Taking a 300MW thermal power unit and a 3.0MPa steam pressure required by heat users as an example, this paper describes the specific implementation process of this device.
[0032] When the boiler load is in the high-load range (60%-100%), the control system detects that the difference between the steam parameters in the reheater hot section and the heat user demand parameters is greater than or equal to zero. It then automatically opens the relevant valves connected to the reheater on the first regulating path and closes the valves on other steam supply paths. After steam is extracted from the reheater hot section, it enters the desuperheater and pressure reducer. Based on the heat user demand, the desuperheater and pressure reducer lowers the steam pressure through internal regulating valves and releases atomized desuperheating water to reduce the steam temperature. Once the steam reaches a pressure of 3.0 MPa and a suitable temperature, it is stably distributed to the heat users via the steam header.
[0033] When the boiler load is in the medium load range (40%-60%), the control system detects that the difference between the steam parameters in the reheater hot section and the heat user demand parameters is less than zero and greater than or equal to a set threshold, such as -1 MPa. It then starts the steam booster pump, simultaneously opening the valves connected to the reheater on the second regulating path and closing valves on other steam supply paths. Steam enters the steam booster pump through the extraction pipeline. The pump's drive unit automatically selects the drive mode based on the pressure difference, boosting the steam to 3.0 MPa. The steam then enters the desuperheater for temperature regulation and is finally supplied to heat users via the steam header.
[0034] When the boiler load is in the low-load range (15%-40%), the control system detects that the difference between the reheater hot section steam parameters and the heat user demand parameters is less than a set threshold, such as -1MPa. Simultaneously, it opens the valves connected to the superheater and reheater on the third regulating path and closes the valves on other steam supply paths. The main steam and reheater hot section steam enter the pressure matching unit, which adjusts the main steam injection of the hot section steam, mixing the main steam and hot section steam to output steam at a pressure of 3.0MPa. After the temperature is adjusted by the desuperheater, the steam is delivered to the heat user through the steam header.
[0035] When the boiler load of the unit is in the start-up / shutdown range (0%-15%), the flame combustion inside the boiler is unstable and not within the normal operating load range, so the unit cannot generate stable steam.
[0036] Throughout the entire operation, the control valve accurately controls the direction and flow of steam in real time according to the system operating status and control commands, ensuring the safe, stable and efficient operation of the steam supply system.
[0037] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A multi-mode steam supply system for a combined heat and power unit, characterized in that: The system includes a superheater that outputs main steam, the superheater being connected to a third regulating path, the superheater being connected to a high-pressure cylinder, the high-pressure cylinder being connected to a reheater that outputs hot-section steam, the reheater being connected to a first regulating path, a second regulating path, and a third regulating path, the reheater being connected to an intermediate regulating valve, the intermediate regulating valve being connected to an intermediate-pressure cylinder, and the first regulating path, the second regulating path, and the third regulating path being connected to a steam header, the steam header outputting to the heat user; The first adjustment path is used to reduce the temperature and pressure of the hot section steam to the heat user's required parameters; the second adjustment path is used to increase the pressure of the hot section steam to the heat user's required parameters while reducing the temperature to the heat user's required parameters; the third adjustment path is used to reduce the temperature of the main steam and the hot section steam to the heat user's required parameters while mixing and matching the pressure of the main steam and the hot section steam to the heat user's required parameters.
2. The multi-mode steam supply system for a combined heat and power unit according to claim 1, characterized in that, Each of the first, second, and third regulating paths is connected to the steam header with a control valve for controlling the on / off state of the corresponding path.
3. The multi-mode steam supply system for a cogeneration unit according to claim 1, characterized in that, The first regulation path includes a steam pressure and temperature regulating device whose input end is connected to the reheater, and whose output end is connected to the steam header.
4. A multi-mode steam supply system for a cogeneration unit according to claim 3, characterized in that, The steam pressure and temperature regulating device is a desuperheater and pressure reducer.
5. A multi-mode steam supply system for a cogeneration unit according to claim 1, characterized in that, The second regulation path includes a steam booster pump whose input end is connected to the reheater, and a steam temperature regulating device 1 whose output end is connected to the steam header.
6. A multi-mode steam supply system for a combined heat and power unit according to claim 5, characterized in that, The steam booster pump includes a booster and a drive unit.
7. A multi-mode steam supply system for a combined heat and power unit according to claim 5, characterized in that, One of the steam temperature regulating devices is a desuperheater.
8. A multi-mode steam supply system for a combined heat and power unit according to claim 1, characterized in that, The third regulation path includes a steam pressure matching regulation device with an input end connected to the superheater, another input end of the steam pressure matching regulation device connected to the reheater, and an output end of the steam pressure matching regulation device connected to a second steam temperature regulation device, the output end of the second steam temperature regulation device connected to the steam header.
9. A multi-mode steam supply system for a cogeneration unit according to claim 8, characterized in that, The steam pressure matching and regulating device is a pressure matcher.
10. A multi-mode steam supply system for a cogeneration unit according to claim 8, characterized in that, The second steam temperature regulating device is a desuperheater.