Peak-adjustable flexible power plant model for flexible carbon capture
By introducing a flue gas bypass system and a liquid storage device into the carbon capture power plant, the problem of uncoordinated energy consumption peak shaving in traditional carbon capture power plants has been solved, achieving efficient carbon dioxide capture and improved system stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANJING HUADUN ELECTRIC POWER INFORMATION SAFETY EVALUATION CO LTD
- Filing Date
- 2026-01-14
- Publication Date
- 2026-04-24
AI Technical Summary
Traditional carbon capture power plants capture a large amount of carbon during peak load periods, resulting in excessive energy consumption and unstable system operation. Conversely, they capture less carbon during off-peak periods, leading to uncoordinated energy consumption peak shaving.
By introducing a flue gas bypass system, rich liquid tank and lean liquid tank into the carbon capture power plant, the carbon dioxide capture process is separated through flue gas diversion and liquid storage. Combined with carbon dioxide compression and storage device, a flexible carbon capture power plant model with peak shaving is formed.
This achieves the staggering of peak electricity demand periods with peak carbon capture energy consumption periods, reducing energy consumption, improving system stability, and effectively capturing carbon dioxide, thereby reducing environmental pollution.
Smart Images
Figure CN121911207A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of flexible model design technology for carbon capture units, specifically relating to a peak-shaving flexible carbon capture power plant model. Background Technology
[0002] In recent years, global climate change has intensified, and environmental problems have become increasingly severe. Integrated energy systems combine multiple energy sources such as electricity, heat, and gas, achieving complementarity and tiered utilization among energy sources, and are an important means to promote the low-carbon development of the energy industry. Carbon capture power plants, as important units in integrated energy system parks, have attracted much attention from researchers. Most existing technologies at home and abroad choose to integrate combined heat and power (CHP) units, power-to-gas (EPG) systems, and carbon capture equipment into a single system to form a carbon capture power plant, thereby addressing the carbon source issues of EPG units and the carbon emissions of CHP units. Based on this, an optimized scheduling model incorporating EPG and carbon capture systems has been established.
[0003] However, traditional carbon capture power plants capture higher amounts during peak load periods and lower amounts during off-peak periods, leading to a missynchronization between the power-to-gas conversion equipment and the carbon capture power plant itself. Furthermore, traditional carbon capture power plants employ a mode of fully absorbing and capturing emitted carbon dioxide, while the amount of carbon dioxide generated by the units during peak load periods is significant, resulting in excessive energy consumption for carbon capture. Excessive energy consumption can easily cause system overload, adversely affecting system stability.
[0004] The problem of uncoordinated energy consumption and peak shaving in traditional carbon capture power plants means that during peak load periods, carbon capture power plants need to perform a large number of carbon capture operations while outputting power. Excessive carbon capture energy consumption can lead to system overload risks. Therefore, it is necessary to develop a new peak-shaving flexible carbon capture power plant model to solve the existing problems. Summary of the Invention
[0005] The purpose of this invention is to provide a flexible carbon capture power plant model with peak-shaving capability to solve the problem of inconsistent energy consumption peak-shaving in traditional carbon capture power plants.
[0006] To achieve the above objectives, the present invention provides the following technical solution: a flexible power plant model with peak-shaving flexible carbon capture, comprising:
[0007] A flue gas bypass system for collecting carbon dioxide flue gas;
[0008] A carbon capture power plant connected to the flue gas bypass system;
[0009] The carbon capture power plant includes:
[0010] A lean solution tank is used to store lean solution.
[0011] Rich solution tank, used to store rich solution;
[0012] A carbon dioxide absorption tower is used to absorb carbon dioxide flue gas from the flue gas bypass system and convert the lean liquor into rich liquor.
[0013] A regeneration tower is used to release carbon dioxide from the converted rich liquor and convert it back into lean liquor.
[0014] A carbon dioxide compression storage device is used to compress and store carbon dioxide released from rich liquid.
[0015] Preferably, the carbon capture power plant further includes:
[0016] The spray system, installed inside the carbon dioxide absorption tower, is used to bring the lean liquid into contact with the carbon dioxide flue gas.
[0017] Preferably, the carbon capture power plant further includes:
[0018] A circulating pump is used to transport the lean liquor regenerated in the regeneration tower to the spray system of the carbon dioxide absorption tower.
[0019] Preferably, the carbon dioxide absorption tower uses an ethanolamine solution to absorb the introduced carbon dioxide flue gas.
[0020] Preferably, the carbon dioxide release from the rich liquid includes a heating process or a depressurization process.
[0021] Preferably, the mathematical model of the carbon capture power plant includes:
[0022] ;
[0023] in, This represents the total output of the carbon capture unit during time period t; This indicates the fixed energy consumption of the carbon capture unit; This represents the operating energy consumption of the carbon capture unit during time period t; This represents the net output of the carbon capture unit during time period t; Indicates the carbon capture unit capture unit Energy consumption; This indicates the amount of carbon captured by the carbon capture unit at time t. Total amount; Indicates the efficiency of the carbon capture unit; This indicates the carbon capture unit's output during time period t. The total amount; Indicates the carbon emission intensity of the carbon capture unit; This represents the net carbon emissions of the carbon capture unit during time period t; Indicates compressor efficiency; This indicates the upper limit of the output of the carbon capture unit.
[0024] Preferably, the mathematical model of the peak-tunable flexible carbon capture power plant model includes:
[0025] ;
[0026] in, , , , These represent the total output, fixed energy consumption, operating energy consumption, and net output of the flexible carbon capture unit during time period t, respectively. Indicates the capture unit of the flexible carbon capture unit Energy consumption; Indicates the compressor processing time during period t. The amount; This indicates the amount of carbon capture solution supplied to the storage tank of the flexible carbon capture unit during time period t. quantity; This represents the net carbon emissions of the flexible carbon capture power plant unit during time period t. This indicates the amount of carbon captured by the flexible carbon capture unit during time period t. Total amount; This indicates the output of the flexible carbon capture unit during time period t. The total amount; This indicates the upper limit of the output of the flexible carbon capture unit; Indicates the efficiency of the carbon capture unit; Indicates the carbon emission intensity of the carbon capture unit; This indicates the flue gas split ratio.
[0027] The technical effects and advantages of this invention are as follows: This peak-shaving flexible carbon capture power plant model separates the carbon capture and absorption processes by adding a carbon dioxide storage tank to the carbon capture power plant, thereby achieving effective capture of carbon dioxide generated during fuel combustion power generation during the operation of the carbon capture power plant; it also allows the peak power demand period of the carbon capture unit to be staggered with the peak energy consumption period of carbon capture, achieving peak energy consumption while improving the overall stability of the system. Attached Figure Description
[0028] Figure 1 This is a schematic diagram of the flexible power plant model with peak-shaving flexible carbon capture according to the present invention. Figure 2 This is a schematic diagram of a conventional carbon capture power plant structure according to the present invention; Figure 3 This is a block diagram of the electric-heat-cooling-gas coupled integrated energy system of the present invention; Figure 4 This is a graph showing the electrical load prediction of the present invention. Figure 5 This is a diagram showing the cooling load prediction curve of the present invention; Figure 6 This is a gas load prediction curve diagram of the present invention; Figure 7 This is a heat load prediction curve for the present invention; Figure 8 This is a schematic diagram of carbon emissions under four scenarios of the present invention.
[0029] In the diagram: 10, flue gas bypass system; 20, lean liquor tank; 30, rich liquor tank; 40, carbon dioxide absorber; 21, lean liquor pump; 31, rich liquor pump; 50, heat exchanger; 60, regeneration tower; 70, reboiler; 80, compressor. Detailed Implementation
[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.
[0031] This invention provides, for example Figure 1 , Figure 2 The model of a flexible power plant with peak-shaving and flexible carbon capture shown includes: a flue gas bypass system 10, a rich liquid tank 30, a lean liquid tank 20, a carbon dioxide compression and storage device, and a carbon dioxide absorption tower 40.
[0032] The flue gas bypass system 10, using flue gas diversion technology, can alleviate the problem of insufficient output of carbon capture power plants caused by high energy consumption of carbon capture equipment during peak load periods. In this operating mode, the carbon dioxide flue gas and other impurity flue gas generated by the generator set are divided into two parts for treatment: one part of the flue gas is directly released to the subsequent filtration device through the flue gas bypass system 10, and the other part of the flue gas is sucked into the carbon capture device for subsequent carbon dioxide reuse.
[0033] The rich liquid tank 30 and lean liquid tank 20, by adding carbon dioxide storage tanks in the carbon capture power plant, separate the carbon dioxide capture and absorption processes, and achieve effective capture of carbon dioxide generated by fuel combustion power generation during the operation of the carbon capture power plant; this allows the peak power demand period of the carbon capture unit to be staggered with the peak energy consumption period of carbon capture, thereby achieving energy consumption peak shaving while improving the overall stability of the system.
[0034] The aforementioned carbon dioxide compression and storage device introduces the carbon dioxide flue gas released by the system into the compressor 80, where a portion of the carbon dioxide flue gas is stored and the remaining portion is sent to an electro-gas converter for methanation treatment.
[0035] The carbon dioxide absorption tower 40 uses an ethanolamine solution to absorb the incoming carbon dioxide flue gas, thereby extracting a relatively pure carbon dioxide raw material.
[0036] In terms of hardware, by adding a rich liquid tank 30 and a lean liquid tank 20 to the carbon capture power plant, the carbon dioxide capture and absorption processes are separated, achieving effective capture of carbon dioxide generated by fuel combustion power generation during the operation of the carbon capture power plant; this allows the peak power demand period of the carbon capture unit to be staggered with the peak energy consumption period of carbon capture, achieving peak energy consumption regulation while improving the overall stability of the system. The rich liquid tank 30 is formed by filling the carbon dioxide storage tank with rich liquid, and the lean liquid tank 20 is formed by filling the carbon dioxide storage tank with lean liquid.
[0037] During peak electricity demand periods, the flue gas flow rate can be adjusted through the valves of the flue gas bypass system 10 to reduce the amount of flue gas entering the system. Simultaneously, the energy consumption peak-shaving functions of the rich liquid tank 30 and lean liquid tank 20 are fully utilized, allowing carbon dioxide to be absorbed only into the rich liquid tank 30 without actual carbon capture operation. This not only reduces the energy consumption of the unit's carbon capture and increases net output power but also reduces emissions pollution caused by uncaptured carbon dioxide, resolving the contradiction between the net output of the carbon capture unit and load demand. During off-peak electricity demand periods, the carbon capture unit's power output requirement is lower, so this time period can be fully utilized to analyze the rich liquid stored during peak periods, and the released carbon dioxide can be transported to the power-to-gas (HPC) equipment for methanation treatment. This not only effectively utilizes the HPC unit's output downtime but also solves the raw material supply problem for the HPC equipment. It achieves energy consumption peak-shaving while increasing the system's economic and environmental benefits.
[0038] In terms of software, the total output of a carbon capture power plant consists of three parts: operating energy consumption, stationary energy consumption, and net output. The electrical energy consumed by the compressor (80%) can be considered as the operating energy consumption of the carbon capture equipment, while stationary energy consumption is a fixed value unrelated to carbon emission intensity. The model of a carbon capture power plant is as follows: Figure 2As shown: First, the flue gas containing carbon dioxide enters the flue gas bypass system 10, which acts as a pretreatment and diversion stage. Next, inside the carbon dioxide absorption tower 40, the flue gas entering from the bottom comes into full contact with the lean liquor sprayed from the top of the tower, at which point the lean liquor is transformed into rich liquor, completing the absorption of carbon dioxide and the transfer of substances. Then, the rich liquor entering the rich liquor tank 30 releases carbon dioxide in the regeneration zone through processes such as heating and depressurization, and the rich liquor is transformed back into lean liquor. The carbon dioxide released during the regeneration process is transported to the inlet of the carbon dioxide compression and storage device through a dedicated pipeline, while the lean liquor in the lean liquor tank 20 is returned to the carbon dioxide absorption tower 40 through a circulation pump and pipeline. The top spray system enables the recycling of lean liquor, forming a closed loop of absorption-regeneration-recycling. Finally, the carbon dioxide entering the carbon dioxide compression and storage device undergoes multi-stage compression to reduce its volume from a gaseous state to a high-pressure liquid or supercritical state, facilitating storage. The compressed carbon dioxide is then reused. The circulation pump includes a lean liquor pump 21 connected to the carbon dioxide absorption tower 40 and the lean liquor tank 20, and a rich liquor pump 31 connected to the carbon dioxide absorption tower 40 and the rich liquor tank 30. The lean liquor pump 21 and the rich liquor pump 31 are connected through a heat exchanger 50, which is connected to a reboiler 70, which is connected to a regeneration tower 60.
[0039] The mathematical model for a carbon capture power plant is shown below:
[0040]
[0041] In the formula: It is the total output of the carbon capture unit during time period t; This refers to the fixed energy consumption of the carbon capture unit; This refers to the operating energy consumption of the carbon capture unit during time period t. It is the net output of the carbon capture unit during time period t; It is a carbon capture unit. Energy consumption; It is the carbon capture unit that captures at time t. Total amount; It refers to the efficiency of the carbon capture unit; The carbon capture unit generates during time period t. The total amount; It refers to the carbon emission intensity of the carbon capture unit; This is the net carbon emission of the carbon capture unit during time period t; It refers to compressor efficiency; This is the upper limit of the output of the carbon capture unit;
[0042] As shown in the above formula, the net output power of a traditional carbon capture power plant unit is the total output of the original unit minus the fixed energy consumption and operating energy consumption of the carbon capture unit. This results in a reduction in the capacity of the carbon capture power plant compared to the original system, and its operating efficiency is also affected. Therefore, a flue gas split-flow operation mode is set up to improve the operating efficiency of the carbon capture power plant. The mathematical expression of the carbon capture model after flue gas split-flow is as follows:
[0043]
[0044] In the formula: It is the flue gas split ratio;
[0045] Adopting a flue gas diversion operation mode allows for flexible adjustment of output power at different times, thereby broadening the regulation range of the carbon capture power plant. However, the flue gas diversion operation mode still has drawbacks. The absorption and capture processes of the unit are interconnected, resulting in an inability to effectively improve carbon capture efficiency during low-load periods and an inability to efficiently handle large amounts of carbon dioxide flue gas during high-load periods. In addition, although the carbon dioxide entering the flue gas bypass system 10 does not consume power plant energy, direct emission of carbon dioxide will cause environmental pollution. Therefore, by adding a liquid storage tank, the operational flexibility of the carbon capture power plant can be further improved, forming a peak-shaving flexible carbon capture power plant model, as shown in the figure. Figure 1 As shown, the mathematical model is as follows:
[0046]
[0047] In the formula: , , , These are the total output, fixed energy consumption, operating energy consumption, and net output of the flexible carbon capture unit during time period t. It is a flexible carbon capture unit. Energy consumption; The compressor is handling the time period t. The amount; The liquid to be captured is supplied by the storage tank of the flexible carbon capture unit during time period t. quantity; The net carbon emissions of the flexible carbon capture power plant unit during time period t; It is the carbon capture unit that captures carbon during time period t. Total amount; It is generated by the flexible carbon capture unit during the t-period. The total amount; This is the upper limit of the output of the flexible carbon capture unit; the flue gas split ratio introduced in the model and introduction To differentiate it from traditional units, the flexible carbon capture unit captures carbon during time period t. Total It is also different from traditional units.
[0048] by Figure 3 Taking the integrated energy system of an industrial park in a certain region of East China as an example, the demand for electricity, heat, cooling, and gas loads is as follows: Figures 4-7 As shown in Table 1, the parameters of each unit in the system are shown in Table 2, and other correlation coefficients of the system are shown in Table 2.
[0049] Table 1 Equipment Parameters
[0050]
[0051] Table 2 Other System Parameters
[0052]
[0053] To verify the effectiveness of the proposed modified peak-shaving flexible carbon capture power plant, the following four scenarios were set up for comparative analysis.
[0054] Scenario 1: An optimized scheduling and operation method for the integrated energy system under consideration without introducing carbon capture units;
[0055] Scenario 2: Introducing an optimized scheduling and operation method for traditional flue gas diversion carbon capture units into the integrated energy system under consideration;
[0056] Scenario 3: Introducing an optimized scheduling and operation method for traditional rich liquid split carbon capture units into the integrated energy system under consideration;
[0057] Scenario 4: Introduce optimized scheduling and operation methods for modified flexible carbon capture power plants with peak shaving capabilities into the integrated energy system under consideration.
[0058] Figure 8 The document showcases carbon emissions under four scenarios. Scenario 1, lacking carbon capture equipment to absorb carbon dioxide from high-emission units, results in high carbon emissions. Scenario 2 introduces a traditional flue gas split-flow carbon capture power plant, reducing some carbon emissions through its combined operation with an electricity-to-gas (EPG) unit. Scenario 3 replaces Scenario 2 with a rich liquid split-flow unit, increasing the system's carbon penalty; the system begins to limit carbon emissions from high-emission units, leading to reduced emissions. In Scenario 4, the reduction in carbon emissions benefits from the liquid storage device of the flexible carbon capture power plant unit. This device enables peak energy consumption regulation, ensuring high output power during peak load periods, reducing the system's demand on gas turbine units, and thus lowering overall carbon emissions.
[0059] The above analysis shows that adopting a peak-shaving flexible carbon capture power plant operation mode can transfer the energy consumed by carbon capture during high-load periods, while increasing the amount of carbon dioxide flue gas processed during low-load periods. This improves the system's operational flexibility and expands the net output power range of the carbon capture power plant. Furthermore, the stored carbon dioxide flue gas can be supplied to the power-to-gas (EPG) equipment as feedstock for methane production, helping the system absorb more wind and solar power resources and improving its economic and environmental benefits.
[0060] like Figure 3 The block diagram of the electric-heat-cool-gas coupled integrated energy system shown includes the following main equipment: (1) Energy supply side: upper-level power grid, heat network, gas network, cooling network, as well as clean energy such as carbon capture power plants and wind power and photovoltaic power; (2) Energy conversion side: gas boilers, gas turbines, hydrogen fuel cells, electrolyzers, absorption chillers and electric chillers; (3) Energy storage side: heat storage and hydrogen storage.
[0061] like Figures 4-7 The electricity, heat, cooling, and gas load forecast curves shown are a graphical representation of the predicted trend of electricity / energy demand (load) changes within the integrated energy system park over a future period.
[0062] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A flexible power plant model with peak-shaving flexible carbon capture, characterized in that: include: A flue gas bypass system for collecting carbon dioxide flue gas; A carbon capture power plant connected to the flue gas bypass system; The carbon capture power plant includes: A lean solution tank is used to store lean solution. Rich solution tank, used to store rich solution; A carbon dioxide absorption tower is used to absorb carbon dioxide flue gas from the flue gas bypass system and convert the lean liquor into rich liquor. A regeneration tower is used to release carbon dioxide from the converted rich liquor and convert it back into lean liquor. A carbon dioxide compression storage device is used to compress and store carbon dioxide released from rich liquid.
2. The flexible power plant model with peak-shaving flexible carbon capture according to claim 1, characterized in that: The carbon capture power plant also includes: The spray system, installed inside the carbon dioxide absorption tower, is used to bring the lean liquid into contact with the carbon dioxide flue gas.
3. The flexible power plant model with peak-shaving flexible carbon capture according to claim 1, characterized in that: The carbon capture power plant also includes: A circulating pump is used to transport the lean liquor regenerated in the regeneration tower to the spray system of the carbon dioxide absorption tower.
4. The flexible power plant model with peak-shaving flexible carbon capture according to claim 1, characterized in that: The carbon dioxide absorption tower uses an ethanolamine solution to absorb the introduced carbon dioxide flue gas.
5. A flexible power plant model for peak-shaving flexible carbon capture according to claim 1, characterized in that: The release of carbon dioxide from the rich liquid includes either a heating process or a depressurization process.
6. A flexible power plant model for peak-shaving flexible carbon capture according to any one of claims 1-5, characterized in that: The mathematical model of the carbon capture power plant includes: ； in, This represents the total output of the carbon capture unit during time period t; This indicates the fixed energy consumption of the carbon capture unit; This represents the operating energy consumption of the carbon capture unit during time period t; This represents the net output of the carbon capture unit during time period t; Indicates the carbon capture unit capture unit Energy consumption; This indicates the amount of carbon captured by the carbon capture unit at time t. Total amount; Indicates the efficiency of the carbon capture unit; This indicates the carbon capture unit's output during time period t. The total amount; Indicates the carbon emission intensity of the carbon capture unit; This represents the net carbon emissions of the carbon capture unit during time period t; Indicates compressor efficiency; This indicates the upper limit of the output of the carbon capture unit.
7. A flexible power plant model for peak-shaving flexible carbon capture according to any one of claims 1-5, characterized in that: The mathematical model of the flexible carbon capture power plant model with peak shaving capability includes: ； in, , , , These represent the total output, fixed energy consumption, operating energy consumption, and net output of the flexible carbon capture unit during time period t, respectively. Indicates the capture unit of the flexible carbon capture unit Energy consumption; Indicates the compressor processing time during period t. The amount; This indicates the amount of carbon capture solution supplied to the storage tank of the flexible carbon capture unit during time period t. quantity; This represents the net carbon emissions of the flexible carbon capture power plant unit during time period t. This indicates the amount of carbon captured by the flexible carbon capture unit during time period t. Total amount; This indicates the output of the flexible carbon capture unit during time period t. The total amount; This indicates the upper limit of the output of the flexible carbon capture unit; Indicates the efficiency of the carbon capture unit; Indicates the carbon emission intensity of the carbon capture unit; This indicates the flue gas split ratio.