System for capturing carbon dioxide in flue gas by using circulating water

Abstract

The system comprises a kettle body, a spraying device and a gas collecting hood, the interior of the kettle body is divided into a plurality of spraying cavities through partition plates, each partition plate is connected with the inner wall of the kettle body in a sealed mode to form a collecting bin, an exhaust port is formed in the top of the kettle body, and a gas outlet is formed in the top of the kettle body. A water inlet and an alkali adding opening are formed in the positions, close to the bottom, of the kettle body, each spraying cavity is provided with a circulating liquid inlet, a liquid outlet, a gas inlet and a gas outlet, the gas inlet is connected with a gas inlet pipe, and the spraying device is suitable for spraying flue gas discharged by the gas inlet pipe; the gas collecting hood is arranged at the top in each spraying chamber, and the gas collecting hood is suitable for collecting the sprayed flue gas in the spraying chamber and transferring the flue gas into the next spraying chamber or the exhaust port. The circulating water of the power plant is used for spraying the flue gas, so that carbon dioxide in the flue gas reacts with calcium ions in the circulating water, the carbon dioxide in the flue gas can be captured, and the calcium ions in the circulating water can be removed.

Description

Technical Field

[0001] The invention relates to the technical field of flue gas purification, and in particular to a system for capturing carbon dioxide in flue gas by using circulating water. Background Art

[0002] After desulfurization, denitrification and dust removal, the flue gas of coal-fired power plants has a carbon dioxide content of about 15%, which is the main source of greenhouse gas emissions from coal-fired power plants. Conventional absorption methods are usually used to capture carbon dioxide, but they consume high energy and have high costs. The calcium ion concentration in the circulating water of power plants is generally above 500 mg / L. Excessive calcium ion concentration can easily lead to scaling of the condenser system, affecting the safe operation of the unit. Therefore, a system that uses circulating water to capture carbon dioxide in flue gas can be designed, which can not only capture carbon dioxide in flue gas, but also remove calcium from circulating water. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, an embodiment of the present invention provides a system for capturing carbon dioxide in flue gas using circulating water, which can capture carbon dioxide in flue gas and realize decalcification of circulating water.

[0004] The embodiment of the present invention proposes a system for capturing carbon dioxide in flue gas with circulating water, comprising: a kettle body, a spray device and a gas collecting hood, wherein the interior of the kettle body is divided into a plurality of spray chambers by a horizontally arranged partition, each partition is sealed and connected to the inner wall of the kettle body to form a collection bin for collecting liquid, an exhaust port is arranged on the top of the kettle body, a water inlet and an alkali adding port are arranged near the bottom of the kettle body, each spray chamber is respectively provided with a circulating liquid inlet, a liquid outlet, an air inlet and an air outlet, the liquid outlet is arranged at the bottom of the side of the collection bin, the circulating liquid inlet and the air outlet are arranged at the top of the spray chamber, the air inlet is connected to the air inlet pipe, and the air inlet pipe is arranged at A plurality of air outlets are provided on the air inlet pipe at the lower part of the spray chamber, and the air inlet pipes of all the spray chambers are connected in parallel; the spray device is arranged at the upper part of each spray chamber and above the air inlet pipe, the spray device is connected to the circulating liquid inlet, and the spray device is suitable for spraying the smoke discharged from the air inlet pipe; the gas collecting hood is arranged at the top of each spray chamber, the gas collecting hood is connected to the air outlet, the air outlets of all the spray chambers are connected through exhaust pipes, the exhaust pipe of each spray chamber is connected to the air inlet pipe through a connecting pipe, and the gas collecting hood is suitable for collecting the smoke in the spray chamber that has been sprayed and transferring it to the next spray chamber or exhaust port.

[0005] In some embodiments, the spray device includes a spray head, and a plurality of nozzles are evenly distributed at the bottom of the spray head, and the nozzles spray downward.

[0006] In some embodiments, the gas collecting hood is a conical structure that is narrow at the top and wide at the bottom, and the spray head is arranged inside the gas collecting hood near the top.

[0007] In some embodiments, the circulating liquid inlet and outlet of each spray chamber are connected via a circulating liquid pipeline, a circulating pump is connected to the circulating liquid pipeline, and the circulating liquid pipelines of two adjacent spray chambers are connected via a riser.

[0008] In some embodiments, a filler layer is provided between the air collecting hood and the air inlet pipe.

[0009] In some embodiments, the air inlet pipe is arranged in a horizontal direction, and the air outlet is opened at the bottom of the air inlet pipe.

[0010] In some embodiments, an exhaust hole is provided at the bottom of the air inlet pipe, and the aperture of the exhaust hole increases from one end of the air inlet to the other end of the air inlet pipe.

[0011] In some embodiments, a slurry discharge port is provided at the bottom of the collecting bin, the slurry discharge port is connected to a slurry discharge pipeline, and a slurry discharge pump is connected to the slurry discharge pipeline.

[0012] In some embodiments, the spray chambers are arranged vertically from bottom to top in the kettle body. The smoke enters the spray chamber at the bottom layer and then enters the spray chambers above in turn for spraying layer by layer, and is finally discharged from the exhaust port at the top of the kettle body. The exhaust pipe of the spray chamber at the lower layer is connected to the air inlet pipe of the adjacent spray chamber at the upper layer through a circulating air pipeline.

[0013] In some embodiments, a drain pipe is connected to the circulating liquid pipeline on the top layer, and the drain pipe is connected to a water purification device. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings.

[0015] in:

[0016] Figure 1 This is a schematic diagram of the structure of a system for capturing carbon dioxide in flue gas using circulating water in an embodiment of the present invention;

[0017] Figure 2 for Figure 1 A bottom view of the intake pipe in FIG.

[0018] Reference numerals:

[0019] 1. Circulating air pipeline; 2. Partition; 3. Air collecting hood; 4. Packing layer; 5. Connecting pipe; 6. Draft fan; 7. Alkali solution pump; 8. Water pump; 9. Air inlet pipe; 91. Air outlet; 10. Water purification device; 11. Riser; 12. Sprinkler head; 13. Circulating liquid pipeline; 14. Circulating pump; 15. Slurry discharge pump. DETAILED DESCRIPTION

[0020] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0021] The following describes a system for capturing carbon dioxide in flue gas using circulating water according to an embodiment of the present invention with reference to the accompanying drawings.

[0022] like Figure 1-2 As shown, an embodiment of the present invention proposes a system for capturing carbon dioxide in flue gas with circulating water, comprising: a kettle body, a spray device and a gas collecting hood 3. The interior of the kettle body is divided into a plurality of spray chambers by a horizontally arranged partition 2. Each partition 2 is sealed and connected to the inner wall of the kettle body to form a collection bin for collecting liquid. An exhaust port is provided on the top of the kettle body, and a water inlet and an alkali adding port are provided near the bottom of the kettle body. Each spray chamber is respectively provided with a circulating liquid inlet, a liquid outlet, an air inlet and an air outlet. The liquid outlet is provided at the bottom of the side of the collecting bin, and the circulating liquid inlet and the air outlet are provided at the top of the spray chamber. The air inlet is connected to an air inlet pipe 9, and the air inlet pipe 9 is arranged at A plurality of air outlet holes 91 are provided on the air inlet pipe 9 at the lower part of the spray chamber, and the air inlet pipes 9 of all the spray chambers are connected in parallel; a spray device is arranged at the upper part of each spray chamber and above the air inlet pipe 9, the spray device is connected to the circulating liquid inlet, and the spray device is suitable for spraying the smoke discharged from the air inlet pipe 9; an air collecting hood 3 is arranged at the top of each spray chamber, the air collecting hood 3 is connected to the air outlet, the air outlets of all the spray chambers are connected through exhaust pipes, the exhaust pipe of each spray chamber is connected to the air inlet pipe 9 through a connecting pipe 5, and the air collecting hood 3 is suitable for collecting the smoke in the spray chamber that has been sprayed and transferring it to the next spray chamber or exhaust port.

[0023] The embodiment of the present invention arranges a spraying device in the kettle body, and uses the circulating water of the power plant to spray the flue gas, so that the carbon dioxide in the flue gas reacts with the calcium ions in the circulating water to generate calcium carbonate, which can not only capture the carbon dioxide in the flue gas, but also remove the calcium ions in the circulating water, adjust the pH of the circulating water, and use the circulating water of the power plant to capture carbon dioxide, which can reduce costs. Moreover, the circulating water after the calcium ions are removed can also be returned to the system for use as make-up water, which reduces the calcium hardness of the circulating water and reduces the scaling risk of the circulating water system.

[0024] Further, the alkali adding port is connected to an alkali liquid pipe, and an alkali liquid pump 7 is connected to the alkali liquid pipe. The alkali liquid introduced into the alkali liquid pipe can be sodium hydroxide. By adding alkali, the slurry can be controlled to be weakly alkaline (pH=11), ensuring that carbon dioxide exists in the form of carbonate.

[0025] In some embodiments, the spray device includes a spray head 12 , and a plurality of nozzles are evenly distributed at the bottom of the spray head 12 , and the nozzles spray downward.

[0026] In some embodiments, the gas collecting hood 3 is a conical structure that is narrow at the top and wide at the bottom, and the spray head 12 is disposed inside the gas collecting hood 3 near the top.

[0027] In some embodiments, the circulating liquid inlet and outlet of each spray chamber are connected by a circulating liquid pipeline 13, and a circulating pump 14 is connected to the circulating liquid pipeline 13. The circulating liquid pipelines 13 of two adjacent spray chambers are connected by a rising pipe 11, and the rising pipe 11 is used to flow the circulating water into each spray chamber for circulation. By setting the circulating liquid pipeline 13 and the rising pipe 11, the circulating water after spraying can be circulated and sprayed, so that the calcium ions in the circulating water can fully react with the carbon dioxide in the flue gas.

[0028] Furthermore, a third control valve is connected to the circulating liquid pipeline 13 , and a fourth control valve is connected to the rising pipe 11 .

[0029] In some embodiments, a packing layer 4 is provided between the gas collecting hood 3 and the air inlet pipe 9. Filling the packing layer 4 with inert solid materials can increase the gas-liquid contact surface and further promote the reaction between calcium ions in the circulating water and carbon dioxide in the flue gas.

[0030] Furthermore, the packing layer 4 is a ball ring packing or a step ring packing.

[0031] In some embodiments, Figure 2 As shown, the air inlet pipe 9 is arranged in the horizontal direction, and the air outlet hole 91 is opened at the bottom of the air inlet pipe 9. It is prevented that the circulating water enters the air inlet pipe 9 through the air outlet and causes poor air outlet.

[0032] In some embodiments, Figure 2 As shown, a discharge hole 91 is provided at the bottom of the air inlet pipe 9, and the aperture of the discharge hole 91 increases from one end of the air inlet to the other end of the air inlet pipe 9. This ensures that smoke is discharged evenly from all the discharge holes 91 of the air inlet pipe 9.

[0033] In some embodiments, a slurry discharge port is provided at the bottom of the collecting bin, the slurry discharge port is connected to a slurry discharge pipeline, and the slurry discharge pipeline is connected to a slurry discharge pump 15. The collected slurry is a slurry mixed with calcium carbonate, and calcium carbonate can be prepared using the slurry.

[0034] In some embodiments, the spray chambers are arranged vertically from bottom to top in the kettle body. The smoke enters from the spray chamber on the bottom layer and then enters the spray chambers above in turn for spraying layer by layer, and is finally discharged from the exhaust port on the top of the kettle body. The exhaust pipe of the spray chamber on the lower layer is connected to the air inlet pipe 9 of the adjacent spray chamber on the upper layer through a circulating air pipeline 1.

[0035] Furthermore, a first control valve is provided on the connecting pipe 5. When the first control valve is disconnected, the smoke passes through the spray chamber located relatively lower and then enters the air inlet pipe 9 located relatively upper from the exhaust pipe for spraying again. When the first control valve is connected, part of the smoke enters the spray chamber located relatively lower for spraying, and the other part of the smoke enters the spray chamber located relatively upper for spraying.

[0036] The circulating gas pipeline 1 is provided with a second control valve. When in use, the second control valve of the relatively lower spray chamber is disconnected, and the first control valve is connected. The flue gas is fully sprayed in the relatively lower spray chamber. The flue gas is discharged from the exhaust pipe after one spraying, and then returns to the spray chamber through the circulating gas pipeline 1 for repeated spraying. When the spraying is completed, the second control valve of the relatively lower spray chamber is connected and the first control valve is disconnected, so that the flue gas enters the relatively upper spray chamber through the exhaust pipe and the air inlet pipe 9 of the relatively upper spray chamber in turn. Finally, the flue gas is discharged from the exhaust port at the top of the kettle body.

[0037] Furthermore, the water inlet of the spray chamber at the bottom is connected to a water inlet pipe, and the water inlet pipe is connected to a water pump 8 for quickly introducing circulating water into the kettle body.

[0038] Furthermore, an induced draft fan 6 is connected to the air inlet pipe 9 of the spray chamber at the bottom to quickly introduce the smoke into the kettle body.

[0039] In some embodiments, the circulating liquid pipeline 13 on the top layer is connected to a drain pipe, which is connected to the water purification device 10 and is used to remove calcium and hardness from the water after spraying and then recycle it.

[0040] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0041] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0042] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0044] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0045] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A system for capturing carbon dioxide in flue gas using circulating water, characterized in that: include: A kettle body, wherein the interior of the kettle body is divided into a plurality of spray chambers by a horizontally arranged partition, each of the partitions is sealed and connected to the inner wall of the kettle body to form a collection bin for collecting liquid, an exhaust port is arranged at the top of the kettle body, a water inlet and an alkali adding port are arranged near the bottom of the kettle body, each of the spray chambers is respectively provided with a circulating liquid inlet, a liquid outlet, an air inlet and an air outlet, the liquid outlet is arranged at the bottom of the side of the collecting bin, the circulating liquid inlet and the air outlet are arranged at the top of the spray chamber, the air inlet is connected to the air inlet pipe, the air inlet pipe is arranged at a lower position of the spray chamber, a plurality of air outlet holes are opened on the air inlet pipe, and the air inlet pipes of all the spray chambers are connected in parallel; A spray device, the spray device is arranged in the upper part of each spray chamber and is located above the air inlet pipe, the spray device is connected to the circulating liquid inlet, and the spray device is suitable for spraying the smoke discharged from the air inlet pipe; An air collecting hood is arranged at the top of each of the spray chambers, the air collecting hood is connected to the air outlet, the air outlets of all the spray chambers are connected by exhaust pipes, the exhaust pipe of each spray chamber is connected to the air inlet pipe by a connecting pipe, and the air collecting hood is suitable for collecting the smoke that has been sprayed in the spray chamber and transferring it to the next spray chamber or the exhaust port.

2. The system for capturing carbon dioxide in flue gas using circulating water according to claim 1, characterized in that: The spray device comprises a spray head, and a plurality of spray ports are evenly distributed at the bottom of the spray head, and the spray ports spray downward.

3. The system for capturing carbon dioxide in flue gas using circulating water according to claim 2, characterized in that: The gas collecting hood is in a conical structure that is narrow at the top and wide at the bottom, and the spray head is arranged at a position near the top inside the gas collecting hood.

4. The system for capturing carbon dioxide in flue gas using circulating water according to claim 1, characterized in that: The circulating liquid inlet and the liquid outlet of each spray chamber are connected via a circulating liquid pipeline, a circulating pump is connected to the circulating liquid pipeline, and the circulating liquid pipelines of two adjacent spray chambers are connected via a rising pipe.

5. The system for capturing carbon dioxide in flue gas using circulating water according to claim 1, characterized in that: A filler layer is provided between the air collecting hood and the air inlet pipe.

6. The system for capturing carbon dioxide in flue gas using circulating water according to claim 1, characterized in that: The air inlet pipe is arranged in a horizontal direction, and the air outlet is opened at the bottom of the air inlet pipe.

7. The system for capturing carbon dioxide in flue gas using circulating water according to claim 6, characterized in that: A row of air outlet holes is provided at the bottom of the air inlet pipe, and the apertures of the air outlet holes increase sequentially from one end of the air inlet to the other end of the air inlet pipe.

8. The system for capturing carbon dioxide in flue gas using circulating water according to claim 1, characterized in that: A slurry discharge port is provided at the bottom of the collecting bin, the slurry discharge port is connected to a slurry discharge pipeline, and a slurry discharge pump is connected to the slurry discharge pipeline.

9. The system for capturing carbon dioxide in flue gas using circulating water according to claim 1, characterized in that: The spray chambers are arranged vertically from bottom to top in the kettle body. After entering the spray chamber at the bottom layer, the smoke enters the spray chambers located above in turn and is sprayed layer by layer, and is finally discharged from the exhaust port at the top of the kettle body. The exhaust pipe of the spray chamber at the lower layer is connected to the air inlet pipe of the adjacent spray chamber at the upper layer through a circulating air pipeline.

10. The system for capturing carbon dioxide in flue gas using circulating water according to claim 1, characterized in that: The circulating liquid pipeline located on the top layer is connected with a drainage pipe, and the drainage pipe is connected with a water purification device.

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