Energy self-sufficiency system in process of capturing carbon dioxide from tail gas of gas turbine

Abstract

The utility model relates to an energy self-sufficiency system in a process of capturing carbon dioxide from tail gas of a gas turbine. The system comprises a high-grade energy recovery heating medium-tail gas heat exchanger, a middle-grade energy recovery amine liquid-tail gas heat exchanger and a low-grade energy recovery lean and rich amine liquid heat exchanger. By the adoption of the three-stage energy recovery system, energy in tail gas of the gas turbine can be recovered in a stepped mode, and self-sufficiency of carbon dioxide capture energy in the tail gas is achieved. The application of the technology not only greatly reduces the energy consumption in the carbon dioxide trapping process, but also has important significance for promoting sustainable utilization of energy and reducing industrial carbon emission. Through the efficient energy recovery technology, carbon dioxide capture can be completed without depending on external energy supply, development and application of the environmental protection technology are further promoted, and the method is suitable for large-scale marketization application.

Description

A self-sufficient energy system for capturing carbon dioxide from gas turbine exhaust. Technical Field

[0001] This utility model relates to the field of carbon dioxide capture technology, specifically to a self-sufficient energy system for capturing carbon dioxide from gas turbine exhaust. Background Technology

[0002] With increasing global attention focused on climate change, reducing emissions of greenhouse gases such as carbon dioxide has become a top priority. Gas turbines, a common type of power generation equipment, produce large amounts of exhaust gas containing carbon dioxide during operation. Therefore, efficiently capturing carbon dioxide from gas turbine exhaust is crucial for reducing carbon emissions and achieving carbon reduction targets.

[0003] Currently, common carbon dioxide capture methods include chemical absorption, physical adsorption, and membrane separation. However, these methods have some shortcomings when applied to carbon dioxide capture from gas turbine exhaust. For example, chemical absorption methods have high regeneration energy consumption, reaching approximately 3.7-4.2 GJ / t CO2, leading to increased capture costs and poor economic efficiency. Physical adsorption methods have limited adsorption capacity; for example, molecular sieves have an adsorption capacity ≤1.8 mmol / g, which is insufficient to meet the needs of large-scale exhaust gas treatment. Membrane separation methods suffer from membrane materials that are severely affected by impurities, resulting in a lifespan of <800 hours and high costs. Furthermore, the high temperature (typically 100-600℃) and low CO2 concentration (5-15%) of gas turbine exhaust gases lead to low efficiency and high energy costs for traditional technologies. Therefore, there is an urgent need to develop a CO2 capture scheme that is adaptable to high-temperature, low-concentration conditions and combines high efficiency with low energy consumption. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a self-sufficient energy system for capturing carbon dioxide, tailored to the characteristics of gas turbine exhaust gases. Through the cascade utilization of energy, it significantly improves capture efficiency and reduces energy consumption.

[0005] This invention first provides a self-sufficient energy system for capturing carbon dioxide from gas turbine exhaust gas. The system includes: a heat medium-exhaust gas heat exchanger (1), an amine liquid-exhaust gas heat exchanger (2), a lean-rich amine liquid heat exchanger (3), and a matching pipeline and valve system. The heat medium-exhaust gas heat exchanger (1) has its hot-side inlet connected to the gas turbine exhaust gas inlet pipe, and its hot-side outlet connected to the hot-side inlet of the amine liquid-exhaust gas heat exchanger (2). The hot-side outlet of the amine liquid-exhaust gas heat exchanger (2) is connected to the inlet of a scrubbing device. The cold side inlet of the gas heat exchanger (1) is connected to the heat medium circulation return pipe, and the cold side outlet is connected to the hot side inlet of the reboiler (6) through a pipe; the hot side inlet of the lean-rich amine liquid heat exchanger (3) is connected to the bottom outlet of the regeneration tower (5) through a pipe, and the hot side outlet is connected to the amine liquid inlet of the absorption tower; the cold side inlet of the lean-rich amine liquid heat exchanger (3) is connected to the bottom outlet of the absorption tower, and the cold side outlet of the lean-rich amine liquid heat exchanger (3) is connected in sequence to the cold side inlet of the amine liquid-tail gas heat exchanger (2) and the feed inlet of the regeneration tower (5).

[0006] Preferably, the heat medium-exhaust gas heat exchanger (1) and the amine liquid-exhaust gas heat exchanger (2) are tube-box type heat exchangers, and the lean and rich amine liquid heat exchanger (3) is a shell-and-tube type heat exchanger or a plate type heat exchanger.

[0007] According to the system of this utility model, high-grade energy can be recovered through a heat medium-exhaust gas heat exchanger, medium-grade energy can be recovered through an amine liquid-exhaust gas heat exchanger, and low-grade energy can be recovered through a lean-rich amine liquid heat exchanger. Through this three-stage energy recovery system, the energy in the gas turbine exhaust gas can be recovered in stages, achieving self-sufficiency in carbon dioxide capture energy in the exhaust gas without the need for external energy supplementation.

[0008] The system advantages of this utility model are:

[0009] 1) By making full use of the energy in the exhaust gas of the gas turbine, the energy consumption of the external environment during the carbon dioxide capture process is greatly reduced, thereby ensuring that the process has good economic efficiency.

[0010] 2) It provides an energy-saving and efficient system for the carbon capture process of gas turbine exhaust gas, which is suitable for large-scale application of the carbon capture process of gas turbine exhaust gas. Attached Figure Description

[0011] Figure 1 is a schematic diagram of the process flow of this utility model.

[0012] The meanings of the codes in the diagram are as follows:

[0013] a. The energy self-sufficiency system of this utility model;

[0014] 1. Heat medium-exhaust gas heat exchanger;

[0015] 2. Amine liquid-tail gas heat exchanger;

[0016] 3. Amine-rich / lean liquid heat exchanger;

[0017] 4. Absorption tower;

[0018] 5. Regeneration tower;

[0019] 6. Reboiler. Detailed Implementation

[0020] The present invention will be described in detail below with reference to the embodiments and accompanying drawings.

[0021] Example 1

[0022] Please refer to Figure 1 for the specific process flow of this embodiment.

[0023] A self-sufficient energy system for capturing carbon dioxide from gas turbine exhaust gas includes: a heat medium-exhaust gas heat exchanger (1), an amine liquid-exhaust gas heat exchanger (2), a lean-rich amine liquid heat exchanger (3), and a matching pipeline and valve system; wherein, the hot-side inlet of the heat medium-exhaust gas heat exchanger (1) is connected to the gas turbine exhaust gas inlet pipe, and the hot-side outlet is connected to the hot-side inlet of the amine liquid-exhaust gas heat exchanger (2); the hot-side outlet of the amine liquid-exhaust gas heat exchanger (2) is connected to the inlet of a scrubbing device; the heat medium-exhaust gas heat exchanger (1) The cold-side inlet of the heat exchanger (1) is connected to the heat medium circulation return pipe, and the cold-side outlet is connected to the hot-side inlet of the reboiler (6) through a pipe; the hot-side inlet of the lean-rich amine heat exchanger (3) is connected to the bottom outlet of the regeneration tower (5) through a pipe, and the hot-side outlet is connected to the amine inlet of the absorption tower; the cold-side inlet of the lean-rich amine heat exchanger (3) is connected to the bottom outlet of the absorption tower, and the cold-side outlet of the lean-rich amine heat exchanger (3) is connected in sequence to the cold-side inlet of the amine liquid-tail gas heat exchanger (2) and the feed inlet of the regeneration tower (5). The heat medium-tail gas heat exchanger (1) and the amine liquid-tail gas heat exchanger (2) are tube-box type heat exchangers, and the lean-rich amine heat exchanger (3) is a shell-and-tube type heat exchanger or a plate type heat exchanger.

[0024] The exhaust gas from the gas turbine, with an external temperature of 550°C and an oxide content of 10%, is introduced into the hot side of the heat medium-exhaust gas heat exchanger (1) and exchanges heat with the heat medium from the reboiler (6) at a temperature of 150°C. The heat medium is heated to 190°C and its own temperature drops to 220°C before entering the amine liquid-exhaust gas heat exchanger (2) and exchanging heat with the rich amine liquid from the lean and rich amine liquid heat exchanger (3) at a temperature of 105°C. The rich amine liquid is further heated to 115°C and its own temperature drops further to 150°C. After that, the exhaust gas from the gas turbine passes through a scrubbing device and enters the adsorption tower (4). In the absorption tower (4), the lean amine liquid from the lean amine liquid heat exchanger (3) and further cooled absorbs the carbon dioxide in the gas turbine exhaust gas. The carbon dioxide concentration in the exhaust gas discharged from the top of the absorption tower is 0.8%. The rich amine liquid obtained at the bottom of the tower is sent to the lean amine liquid heat exchanger (3) for heat exchange, cooling the lean amine liquid from the regeneration tower (6) at a temperature of 118°C to 78°C, while itself is heated to 105°C.

[0025] Example 2

[0026] Please refer to Figure 1 for the specific process flow of this embodiment.

[0027] As shown in the figure, the system is self-sufficient in energy during the process of capturing carbon dioxide from the exhaust gas of the gas turbine. The lean and rich amine liquid heat exchanger (3) is a plate heat exchanger.

[0028] The exhaust gas from the gas turbine, with an external temperature of 320°C and an oxide content of 7%, is introduced into the hot side of the heat medium-exhaust gas heat exchanger (1) and exchanges heat with the heat medium from the reboiler (6) at a temperature of 130°C. The heat medium is heated to 150°C and its own temperature drops to 180°C before entering the amine liquid-exhaust gas heat exchanger (2) and exchanging heat with the rich amine liquid from the lean and rich amine liquid heat exchanger (3) at a temperature of 90°C. The rich amine liquid is further heated to 105°C and its own temperature drops further to 120°C. After that, the exhaust gas from the gas turbine passes through a scrubbing device and enters the adsorption tower (4). In the absorption tower (4), the lean amine liquid from the lean amine liquid heat exchanger (3) and further cooled absorbs the carbon dioxide in the gas turbine exhaust gas. The carbon dioxide concentration in the exhaust gas discharged from the top of the absorption tower is 2.5%. The rich amine liquid obtained at the bottom of the tower is sent to the lean amine liquid heat exchanger (3) for heat exchange, cooling the lean amine liquid from the regeneration tower (6) at a temperature of 110°C to 70°C, while itself is heated to 90°C.

[0029] Example 3

[0030] Please refer to Figure 1 for the specific process flow of this embodiment.

[0031] As shown in the figure, the system is self-sufficient in energy during the process of capturing carbon dioxide from the exhaust gas of the gas turbine. The lean and rich amine liquid heat exchanger (3) is a plate heat exchanger.

[0032] The exhaust gas from the gas turbine, with an external temperature of 480°C and an oxide content of 12%, is introduced into the hot side of the heat medium-exhaust gas heat exchanger (1) and exchanges heat with the heat medium from the reboiler (6) at a temperature of 140°C. The heat medium is heated to 160°C and its own temperature drops to 200°C before entering the amine liquid-exhaust gas heat exchanger (2) and exchanging heat with the rich amine liquid from the lean and rich amine liquid heat exchanger (3) at a temperature of 98°C. The rich amine liquid is further heated to 110°C and its own temperature drops further to 130°C. After that, the exhaust gas from the gas turbine passes through a scrubbing device and enters the adsorption tower (4). In the absorption tower (4), the lean amine liquid from the lean amine liquid heat exchanger (3) and further cooled absorbs the carbon dioxide in the gas turbine exhaust gas. The carbon dioxide concentration in the exhaust gas discharged from the top of the absorption tower is 1.5%. The rich amine liquid obtained at the bottom of the tower is sent to the lean amine liquid heat exchanger (3) for heat exchange, cooling the lean amine liquid from the regeneration tower (6) at a temperature of 125°C to 85°C, while itself is heated to 100°C.

Claims

1. A system for energy self-sufficiency from a process for capturing carbon dioxide from exhaust gases of a combustion engine, characterized by: It includes a heat medium-exhaust gas heat exchanger (1), an amine liquid-exhaust gas heat exchanger (2), a lean-rich amine liquid heat exchanger (3), and supporting piping and valve systems; wherein, the hot side inlet of the heat medium-exhaust gas heat exchanger (1) is connected to the gas turbine exhaust gas inlet pipe, and the hot side outlet is connected to the hot side inlet of the amine liquid-exhaust gas heat exchanger (2); the hot side outlet of the amine liquid-exhaust gas heat exchanger (2) is connected to the inlet of the scrubbing device; the cold side inlet of the heat medium-exhaust gas heat exchanger (1) is connected to the heat medium circulation return. The pipe connection and cold side outlet are connected to the hot side inlet of the reboiler (6) through a pipe; the hot side inlet of the lean and rich amine liquid heat exchanger (3) is connected to the bottom outlet of the regeneration tower (5) through a pipe, and the hot side outlet is connected to the amine liquid inlet of the absorption tower; the cold side inlet of the lean and rich amine liquid heat exchanger (3) is connected to the bottom outlet of the absorption tower, and the cold side outlet of the lean and rich amine liquid heat exchanger (3) is connected in sequence to the cold side inlet of the amine liquid-tail gas heat exchanger (2) and the feed inlet of the regeneration tower (5).

2. The system for energy self-sufficiency in a process for capturing carbon dioxide from the exhaust of a combustion engine according to claim 1, characterized in that, The heat medium-exhaust gas heat exchanger (1) and the amine liquid-exhaust gas heat exchanger (2) are tube-box type heat exchangers, and the lean and rich amine liquid heat exchanger (3) is a shell-and-tube type heat exchanger or a plate type heat exchanger.

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