A method for utilizing carbon dioxide and its device

Abstract

The present invention relates to a method and device for the utilization of carbon dioxide. The method for the utilization of carbon dioxide includes the following steps: introducing the original carbon dioxide into a heat exchange tube, spraying the original up-to-standard discharged wastewater outside the heat exchange tube, so that the original carbon dioxide and the original up-to-standard discharged wastewater perform heat exchange to obtain the heat-exchanged carbon dioxide and the heat-exchanged up-to-standard discharged wastewater; ventilating and cooling the heat-exchanged up-to-standard discharged wastewater to obtain the cooled up-to-standard discharged wastewater; introducing the heat-exchanged carbon dioxide into the cooled up-to-standard discharged wastewater to remove calcium ions, and obtaining the up-to-standard discharged wastewater to be separated by an RO membrane. The method for the utilization of carbon dioxide can remove carbon dioxide, concentrate the up-to-standard discharged wastewater, and reduce the hardness of the up-to-standard discharged wastewater.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon dioxide treatment, and particularly relates to a method and device for utilizing carbon dioxide. Background Art

[0002] When factories emit carbon dioxide flue gas, they also produce a large amount of wastewater. After the wastewater is treated, it can meet the discharge standards. However, currently, environmental protection also requires zero discharge of water. In the case of zero discharge of water, the conventional method is to perform membrane concentration on the wastewater that meets the discharge standards. After membrane concentration, evaporation crystallization is carried out to separate water and salts in the water. The water is reused, and the salts are treated as solid waste or commercial salts, thereby achieving zero discharge of wastewater. Membrane concentration includes two steps: RO membrane separation and DTRO membrane concentration. RO membrane separation obtains pure water and concentrated water that can be utilized by the factory. The concentrated water is concentrated by DTRO membrane, and after DTRO membrane concentration, it is evaporated and crystallized by an evaporation crystallizer. The commonly used DTRO pressure now reaches 140 kg, which is to increase the concentration of water and reduce the amount of water entering the evaporation crystallization. Before membrane concentration, it is necessary to remove insoluble salts, and this insoluble salt is mainly calcium carbonate. Because the calcium hardness and carbonate concentration both increase during the membrane concentration process, it is easy to form calcium carbonate deposition on the membrane surface, causing the membrane pores to be blocked and affecting the normal operation of the membrane.

[0003] The invention patent with the application publication number CN113200615A discloses a method and system for electrochemically reducing the hardness of wastewater. The method includes the following steps: the pretreated wastewater is introduced into an electrochemical hardness removal device for electrolysis, and then reacts with the dispersed carbon dioxide to obtain the wastewater after hardness removal, and then through solid-liquid separation, the water with removed hardness is obtained; the electrochemical hardness removal device includes a closed electrolytic cell, and a cathode and an anode are provided inside or outside the electrode cell. This method uses an electrochemical method to remove the hardness of wastewater, but the carbon dioxide used only participates in the calcium carbonate precipitation, and the utilization efficiency is not high. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for utilizing carbon dioxide. This method for utilizing carbon dioxide can remove carbon dioxide, concentrate the wastewater that meets the discharge standards to reduce the wastewater discharge amount, and can also reduce the hardness of the wastewater that meets the discharge standards.

[0005] Another purpose of the present invention is to provide a device for utilizing carbon dioxide.

[0006] In order to achieve the above purposes, the technical solutions adopted by the present invention are as follows:

[0007] A method for utilizing carbon dioxide includes the following steps:

[0008] 1) Heat exchange and concentration: Pass the original carbon dioxide into the heat exchange tube, and spray the original up-to-standard discharged wastewater outside the heat exchange tube, so that the original carbon dioxide and the original up-to-standard discharged wastewater conduct heat exchange to obtain the heat-exchanged carbon dioxide and the heat-exchanged up-to-standard discharged wastewater;

[0009] 2) Cooling and concentration: Ventilate and cool the heat-exchanged up-to-standard discharged wastewater to obtain the cooled up-to-standard discharged wastewater;

[0010] 3) Scale removal: Pass the heat-exchanged carbon dioxide into the cooled up-to-standard discharged wastewater to remove calcium ions and obtain the up-to-standard discharged wastewater to be separated by the RO membrane.

[0011] Further, in step 2), the cooling and concentration is to spray the heat-exchanged up-to-standard discharged wastewater from top to bottom onto the packing layer and ventilate the packing layer to cool and concentrate the heat-exchanged up-to-standard discharged wastewater.

[0012] Further, in step 2), the temperature of the cooled up-to-standard discharged wastewater is 20 - 40 °C, and the flow rate of the cooled up-to-standard discharged wastewater is 3 - 50 t / h.

[0013] Further, in step 1), the flow rate of the original carbon dioxide during the heat exchange and concentration process is 10 - 25 m / s, and the spraying flow rate of the original up-to-standard discharged wastewater is 50 - 500 t / h.

[0014] Further, in step 1), the temperature of the original carbon dioxide entering the heat exchange tube is 100 - 300 °C, and the temperature of the original carbon dioxide leaving the heat exchange tube is 80 - 280 °C; the original temperature of the original up-to-standard discharged wastewater is 10 - 25 °C, and the temperature of the heat-exchanged up-to-standard discharged wastewater is 20 - 40 °C.

[0015] Further, in step 3), an electrode group for electric scale absorption is provided during scale removal to precipitate calcium carbonate in time.

[0016] A device for utilizing carbon dioxide includes a tower body, in which a heat exchange and concentration component, a cooling and concentration component, and a scale removal component are provided; the heat exchange and concentration component includes a heat exchange tube for the flow of the original carbon dioxide and a spraying tube for spraying the original up-to-standard discharged wastewater onto the heat exchange tube; the cooling and concentration component includes a packing layer for the inflow of the heat-exchanged up-to-standard discharged wastewater and a ventilation structure for ventilating the packing layer, and the packing layer is located below the heat exchange tube; the scale removal component includes a carbon dioxide absorption water tank provided below the packing layer and a carbon dioxide circulation tube led from the heat exchange tube to the carbon dioxide absorption water tank.

[0017] Further, the ventilation structure includes a ventilation inlet provided on the side of the packing layer and an exhaust fan provided at the upper part of the tower body, and an air duct for the exhaust fan to draw air is provided in the tower body.

[0018] Further, the tower body is divided into left and right sides, which are separated by a partition. From top to bottom, the left side of the tower body is successively provided with a heat exchange and concentration assembly, a packing layer, and a carbon dioxide absorption water tank. From top to bottom, the right side of the tower body is the air duct. The exhaust fan is arranged at the upper end of the right side of the tower body, and the ventilation inlet is arranged on the left side of the tower body. A ventilation outlet is arranged on one side of the packing layer opposite to the ventilation inlet. The exhaust fan draws air to form a negative pressure in the packing layer to vaporize and cool the qualified discharged wastewater after heat exchange.

[0019] Further, the carbon dioxide absorption water tank includes an air venting tank on the left side and an electric scale removal tank on the right side. The air venting tank is communicated with the electric scale removal tank to enable the water on both sides to flow back and forth. The heat-exchanged carbon dioxide is introduced into the air venting tank, and an electrode group for electric scale removal is arranged in the electric scale removal tank.

[0020] Advantages of the present invention:

[0021] In the method for utilizing carbon dioxide of the present invention, during the heat exchange and concentration process, the original carbon dioxide is introduced into the heat exchange tubes of the evaporative cooling tower, and the original qualified discharged wastewater is sprayed outside the heat exchange tubes. After the original qualified discharged wastewater absorbs the heat of the original carbon dioxide, part of the water evaporates, and the original qualified discharged wastewater is concentrated. The original qualified discharged wastewater can be concentrated by more than ten times, or the concentration multiple can be determined according to the on-site process requirements to be 4 - 20 times. The qualified discharged wastewater after heat exchange has been concentrated once, and the concentrations of various ions are relatively high, which are easy to remove when absorbing carbon dioxide to remove calcium ions subsequently, and are also easy to remove other ions such as chloride ions and sulfate ions during subsequent RO membrane separation. The temperature of the qualified discharged wastewater after heat exchange is relatively high and needs to be cooled. During the cooling process, ventilation is carried out to further concentrate it. Based on the original qualified discharged wastewater, the cooled qualified discharged wastewater has been concentrated twice, which is easy to remove when absorbing carbon dioxide to remove calcium ions subsequently, and is also easy to remove other ions during subsequent RO membrane separation. The heat of carbon dioxide is used to heat the original qualified discharged wastewater, and then ventilation is used to cool and concentrate the qualified discharged wastewater after heat exchange, realizing the two-stage concentration of the original qualified discharged wastewater. Since the original qualified discharged wastewater has been concentrated twice, it does not need to be concentrated by DTRO membrane after RO membrane separation and can directly enter the evaporation crystallizer for evaporation crystallization, eliminating the DTRO membrane concentration and saving a large amount of energy. The heat energy of carbon dioxide emissions replaces the electrical energy of membrane concentration.

[0022] In the method for utilizing carbon dioxide of the present invention, during the scale removal process, the heat-exchanged carbon dioxide is introduced into the cooled qualified discharged wastewater concentrated twice. The heat-exchanged carbon dioxide dissolves in the water to form carbonate radicals, and the heat of the heat-exchanged carbon dioxide is exchanged with the cooled qualified discharged wastewater again. The following reaction occurs between the heat-exchanged carbon dioxide and the cooled qualified discharged wastewater:

[0023] 2H2O⇌2H + +2OH- ⇌ H2 + 2OH -

[0024] OH - + CO2 ⇌ HCO3 3-

[0025] OH - + HCO3 3- ⇌ CO3 2- + H2O

[0026] Ca 2+ + CO3 2- ⇌ CaCO3

[0027] When carbon dioxide after heat exchange is introduced into the cooled up-to-standard discharged wastewater, the ability of the cooled up-to-standard discharged wastewater to dissolve hydrogen gas will decrease, promoting the shift of the ionization equilibrium of water and tending to form hydroxide ions. The formation of hydroxide ions quickly absorbs carbon dioxide.

[0028] In the method for utilizing carbon dioxide of the present invention, the cooled up-to-standard discharged wastewater is treated by electro-scale removal. Calcium, as a cation, moves towards the cathode region and quickly forms calcium carbonate scale after enrichment and precipitates on the cathode, and the calcium carbonate can be quickly removed. Brief Description of the Drawings

[0029] Figure 1 It is a schematic structural diagram of the device for utilizing carbon dioxide in Embodiment 1 of the present invention.

[0030] In the figure: 1. Tower body; 2. Heat exchange and concentration assembly; 21. Heat exchange tube; 22. Spray pipe; 3. Cooling and concentration assembly; 31. Packing layer; 32. Ventilation structure; 321. Ventilation inlet; 322. Exhaust fan; 323. Air duct; 4. Scale removal assembly; 41. Carbon dioxide absorption water tank; 411. Ventilation tank; 412. Electro-scale removal tank; 42. Carbon dioxide circulation pipe; 5. Electrode group. Detailed Embodiments

[0031] The present invention will be further described below in conjunction with the embodiments of the present invention and the drawings.

[0032] Embodiment 1

[0033] The device for utilizing carbon dioxide in this embodiment includes a square tower body 1. Inside the tower body 1, a heat exchange and concentration assembly 2, a cooling and concentration assembly 3, and a scale removal assembly 4 are sequentially arranged from top to bottom. The tower body is divided into left and right sides, which are separated by a partition.

[0034] The heat exchange and concentration assembly 2 includes a heat exchange tube 21 for the flow of the original carbon dioxide and a spray pipe 22 for spraying the original up-to-standard discharged wastewater onto the heat exchange tube. The heat exchange tubes 21 are arranged in rows and multiple rows are provided at intervals up and down. The spray pipe 22 is located above the heat exchange tube 21. A plurality of spray pipes 22 are provided and a plurality of nozzles (not shown in the figure) are evenly connected to each spray pipe 22.

[0035] The cooling and concentration assembly 3 includes a packing layer 31 for the inflow of the up-to-standard discharged wastewater after heat exchange and a ventilation structure 32 for ventilating the packing layer. The packing layer 31 is located below the heat exchange tube 21. The packing in the packing layer 31 is used to increase the heat exchange area between the up-to-standard discharged wastewater after heat exchange and the flowing air. The ventilation structure 32 includes a ventilation inlet 321 provided on the side of the packing layer and an exhaust fan 322 provided at the upper part of the tower body. A ventilation duct 323 for the exhaust fan to draw air is provided inside the tower body. The heat exchange and concentration assembly and the packing layer are located on the left side of the tower body. The ventilation duct 323 is arranged from top to bottom on the right side of the tower body. The exhaust fan 322 is provided at the upper end of the right side of the tower body. The ventilation inlet 321 is provided on the left side of the tower body. A ventilation outlet (not shown in the figure) is provided on the side of the packing layer opposite to the ventilation inlet. The exhaust fan 322 draws air to form a negative pressure inside the packing layer to vaporize and cool the up-to-standard discharged wastewater after heat exchange. While vaporizing, the water evaporates, so that the up-to-standard discharged wastewater after heat exchange is concentrated.

[0036] The scale removal assembly 4 includes a carbon dioxide absorption water tank 41 provided below the packing layer 31 and a carbon dioxide circulation pipe 42 led out from the heat exchange tube to the carbon dioxide absorption water tank. The carbon dioxide absorption water tank 41 includes a ventilation tank 411 on the left side and an electric scale removal tank 412 on the right side. The ventilation tank 411 is communicated with the electric scale removal tank 412 to enable the water on both sides to flow back and forth. The heat-exchanged carbon dioxide is introduced into the ventilation tank 411. An electrode group 5 for electric scale removal is provided in the electric scale removal tank 412. The ventilation tank and the electric scale removal tank are separately arranged. The ventilation tank is used to receive the cooled up-to-standard discharged wastewater sprayed from the packing layer. Calcium ions in the entire carbon dioxide absorption tank are enriched in the electric scale removal tank to be precipitated as calcium carbonate. The calcium carbonate is concentrated and precipitated in the electric scale removal tank, which is convenient for cleaning, and the ventilation tank is relatively clean.

[0037] The method for utilizing carbon dioxide in this embodiment includes the following steps:

[0038] 1) Heat exchange and concentration: Pass the original carbon dioxide into the heat exchange tube, and spray the original up-to-standard discharged wastewater outside the heat exchange tube, so that the original carbon dioxide and the original up-to-standard discharged wastewater conduct heat exchange to obtain the heat-exchanged carbon dioxide and the heat-exchanged up-to-standard discharged wastewater. The flow rate of the original carbon dioxide is 15 m / s, and the spraying flow rate of the original up-to-standard discharged wastewater is 140 t / h. The temperature of the original carbon dioxide entering the heat exchange tube is 163 °C, and the temperature of the original carbon dioxide leaving the heat exchange tube is 127 °C; the original temperature of the original up-to-standard discharged wastewater is 13 °C, and the temperature of the heat-exchanged up-to-standard discharged wastewater is 36 °C.

[0039] 2) Cooling and concentration: Ventilate and cool the heat-exchanged up-to-standard discharged wastewater. The heat-exchanged up-to-standard discharged wastewater is sprayed from top to bottom onto the packing layer, and air is introduced into the packing layer to cool and concentrate the heat-exchanged up-to-standard discharged wastewater to obtain the cooled up-to-standard discharged wastewater. The temperature of the cooled up-to-standard discharged wastewater is 27 °C, and the flow rate of the cooled up-to-standard discharged wastewater is 8 t / h.

[0040] 3) Scale removal: Pass the heat-exchanged carbon dioxide into the cooled up-to-standard discharged wastewater to remove calcium ions, and at the same time set up an electrode group for electro-scale removal to precipitate calcium carbonate in time to obtain the up-to-standard discharged wastewater to be separated by the RO membrane. The conditions for electro-scale removal are: DC voltage: 17 V, current: 41 A, temperature: 27 °C.

[0041] Example 2

[0042] The device for utilizing carbon dioxide in this example has the same structure as the device for utilizing carbon dioxide in Example 1.

[0043] The method for utilizing carbon dioxide in this example includes the following steps:

[0044] 1) Heat exchange and concentration: Pass the original carbon dioxide into the heat exchange tube, and spray the original up-to-standard discharged wastewater outside the heat exchange tube, so that the original carbon dioxide and the original up-to-standard discharged wastewater conduct heat exchange to obtain the heat-exchanged carbon dioxide and the heat-exchanged up-to-standard discharged wastewater. The flow rate of the original carbon dioxide is 13 m / s, and the spraying flow rate of the original up-to-standard discharged wastewater is 280 t / h. The temperature of the original carbon dioxide entering the heat exchange tube is 235 °C, and the temperature of the original carbon dioxide leaving the heat exchange tube is 153 °C; the original temperature of the original up-to-standard discharged wastewater is 18 °C, and the temperature of the heat-exchanged up-to-standard discharged wastewater is 41 °C.

[0045] 2) Cooling and concentration: Ventilate and cool the heat-exchanged up-to-standard discharged wastewater. The heat-exchanged up-to-standard discharged wastewater is sprayed from top to bottom onto the packing layer, and air is introduced into the packing layer to cool and concentrate the heat-exchanged up-to-standard discharged wastewater to obtain the cooled up-to-standard discharged wastewater. The temperature of the cooled up-to-standard discharged wastewater is 28 °C, and the flow rate of the cooled up-to-standard discharged wastewater is 25 t / h.

[0046] 3) Scale removal: The heat-exchanged carbon dioxide is introduced into the cooled up-to-standard discharged wastewater to remove calcium ions. At the same time, an electrode group for electroscale removal is set to precipitate calcium carbonate in time, and the up-to-standard discharged wastewater to be separated by the RO membrane is obtained. The conditions for electroscale removal are: DC voltage: 15 V, current: 60 A, temperature: 28 °C.

[0047] Example 3

[0048] The device for utilizing carbon dioxide in this example has the same structure as the device for utilizing carbon dioxide in Example 1.

[0049] The method for utilizing carbon dioxide in this example includes the following steps:

[0050] 1) Heat exchange and concentration: The original carbon dioxide is introduced into the heat exchange tube, and the original up-to-standard discharged wastewater is sprayed outside the heat exchange tube, so that the original carbon dioxide and the original up-to-standard discharged wastewater conduct heat exchange to obtain the heat-exchanged carbon dioxide and the heat-exchanged up-to-standard discharged wastewater. The flow rate of the original carbon dioxide is 18 m / s, and the spraying flow rate of the original up-to-standard discharged wastewater is 200 t / h. The temperature of the original carbon dioxide entering the heat exchange tube is 192 °C, and the temperature of the original carbon dioxide leaving the heat exchange tube is 148 °C; the original temperature of the original up-to-standard discharged wastewater is 16 °C, and the temperature of the heat-exchanged up-to-standard discharged wastewater is 38 °C.

[0051] 2) Cooling and concentration: The heat-exchanged up-to-standard discharged wastewater is cooled by ventilation. The heat-exchanged up-to-standard discharged wastewater is sprayed from top to bottom onto the packing layer, and ventilation is carried out to the packing layer to cool and concentrate the heat-exchanged up-to-standard discharged wastewater, and the cooled up-to-standard discharged wastewater is obtained. The temperature of the cooled up-to-standard discharged wastewater is 26 °C, and the flow rate of the cooled up-to-standard discharged wastewater is 15 t / h.

[0052] 3) Scale removal: The heat-exchanged carbon dioxide is introduced into the cooled up-to-standard discharged wastewater to remove calcium ions. At the same time, an electrode group for electroscale removal is set to precipitate calcium carbonate in time, and the up-to-standard discharged wastewater to be separated by the RO membrane is obtained. The conditions for electroscale removal are: DC voltage: 12 V, current: 50 A, temperature: 26 °C.

[0053] Example 4

[0054] The device for utilizing carbon dioxide in this example has the same structure as the device for utilizing carbon dioxide in Example 1.

[0055] The method for utilizing carbon dioxide in this example includes the following steps:

[0056] 1) Heat exchange and concentration: Pass the original carbon dioxide into the heat exchange tube, and spray the original up-to-standard discharged wastewater outside the heat exchange tube, so that the original carbon dioxide and the original up-to-standard discharged wastewater conduct heat exchange to obtain the heat-exchanged carbon dioxide and the heat-exchanged up-to-standard discharged wastewater. The flow rate of the original carbon dioxide is 11 m / s, and the spraying flow rate of the original up-to-standard discharged wastewater is 350 t / h. The temperature of the original carbon dioxide entering the heat exchange tube is 210 °C, and the temperature of the original carbon dioxide leaving the heat exchange tube is 102 °C; the original temperature of the original up-to-standard discharged wastewater is 20 °C, and the temperature of the heat-exchanged up-to-standard discharged wastewater is 39 °C.

[0057] 2) Cooling and concentration: Ventilate and cool the heat-exchanged up-to-standard discharged wastewater. The heat-exchanged up-to-standard discharged wastewater is sprayed from top to bottom onto the packing layer, and air is ventilated to the packing layer to cool and concentrate the heat-exchanged up-to-standard discharged wastewater to obtain the cooled up-to-standard discharged wastewater. The temperature of the cooled up-to-standard discharged wastewater is 28 °C, and the flow rate of the cooled up-to-standard discharged wastewater is 30 t / h.

[0058] 3) Scale removal: Pass the heat-exchanged carbon dioxide into the cooled up-to-standard discharged wastewater to remove calcium ions, and at the same time set up an electrode group for electro-adsorbing scale to precipitate calcium carbonate in time to obtain the up-to-standard discharged wastewater to be separated by the RO membrane. The conditions for electro-adsorbing scale are: DC voltage: 24 V, current: 42 A, temperature: 28 °C.

[0059] Example 5

[0060] The device for utilizing carbon dioxide in this example has the same structure as the device for utilizing carbon dioxide in Example 1.

[0061] The method for utilizing carbon dioxide in this example includes the following steps:

[0062] 1) Heat exchange and concentration: Pass the original carbon dioxide into the heat exchange tube, and spray the original up-to-standard discharged wastewater outside the heat exchange tube, so that the original carbon dioxide and the original up-to-standard discharged wastewater conduct heat exchange to obtain the heat-exchanged carbon dioxide and the heat-exchanged up-to-standard discharged wastewater. The flow rate of the original carbon dioxide is 16 m / s, and the spraying flow rate of the original up-to-standard discharged wastewater is 100 t / h. The temperature of the original carbon dioxide entering the heat exchange tube is 126 °C, and the temperature of the original carbon dioxide leaving the heat exchange tube is 103 °C; the original temperature of the original up-to-standard discharged wastewater is 16 °C, and the temperature of the heat-exchanged up-to-standard discharged wastewater is 36 °C.

[0063] 2) Cooling and concentration: Ventilate and cool the heat-exchanged up-to-standard discharged wastewater. The heat-exchanged up-to-standard discharged wastewater is sprayed from top to bottom onto the packing layer, and air is ventilated to the packing layer to cool and concentrate the heat-exchanged up-to-standard discharged wastewater to obtain the cooled up-to-standard discharged wastewater. The temperature of the cooled up-to-standard discharged wastewater is 27 °C, and the flow rate of the cooled up-to-standard discharged wastewater is 6 t / h.

[0064] 3) Scale removal: The heat-exchanged carbon dioxide is introduced into the cooled up-to-standard discharged wastewater to remove calcium ions. Meanwhile, an electrode group for electro-scale removal is provided to precipitate calcium carbonate in time, and the up-to-standard discharged wastewater to be separated by the RO membrane is obtained. The conditions for electro-scale removal are: DC voltage: 11V, current: 73A, temperature: 27°C.

[0065] Example 6

[0066] The device for utilizing carbon dioxide in this example has the same structure as the device for utilizing carbon dioxide in Example 1.

[0067] The method for utilizing carbon dioxide in this example includes the following steps:

[0068] 1) Heat exchange and concentration: The original carbon dioxide is introduced into the heat exchange tube, and the original up-to-standard discharged wastewater is sprayed outside the heat exchange tube, so that the original carbon dioxide exchanges heat with the original up-to-standard discharged wastewater, and the heat-exchanged carbon dioxide and the heat-exchanged up-to-standard discharged wastewater are obtained. The flow rate of the original carbon dioxide is 25 m / s, and the spraying flow rate of the original up-to-standard discharged wastewater is 450 t / h. The temperature of the original carbon dioxide entering the heat exchange tube is 289°C, and the temperature of the original carbon dioxide leaving the heat exchange tube is 194°C; the original temperature of the original up-to-standard discharged wastewater is 11°C, and the temperature of the heat-exchanged up-to-standard discharged wastewater is 40°C.

[0069] 2) Cooling and concentration: The heat-exchanged up-to-standard discharged wastewater is cooled by ventilation. The heat-exchanged up-to-standard discharged wastewater is sprayed from top to bottom onto the packing layer, and ventilation is carried out to the packing layer, so that the heat-exchanged up-to-standard discharged wastewater is cooled and concentrated, and the cooled up-to-standard discharged wastewater is obtained. The temperature of the cooled up-to-standard discharged wastewater is 27°C, and the flow rate of the cooled up-to-standard discharged wastewater is 31 t / h.

[0070] 3) Scale removal: The heat-exchanged carbon dioxide is introduced into the cooled up-to-standard discharged wastewater to remove calcium ions. Meanwhile, an electrode group for electro-scale removal is provided to precipitate calcium carbonate in time, and the up-to-standard discharged wastewater to be separated by the RO membrane is obtained. The conditions for electro-scale removal are: DC voltage: 14V, current: 95A, temperature: 27°C.

[0071] In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "couple" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

Claims

1. An apparatus for utilizing carbon dioxide, characterized in that, It includes a tower body, in which a heat exchange concentration component, a cooling concentration component and a descaling component are arranged; the heat exchange concentration component includes heat exchange tubes for the original carbon dioxide to flow through and spray pipes for spraying the original up-to-standard discharged wastewater onto the heat exchange tubes; the cooling concentration component includes a packing layer for the heat-exchanged up-to-standard discharged wastewater to flow into and a ventilation structure for ventilating the packing layer, and the packing layer is located below the heat exchange tubes; the descaling component includes a carbon dioxide absorption water tank arranged below the packing layer and a carbon dioxide circulation pipe led out from the heat exchange tubes to the carbon dioxide absorption water tank.

2. The apparatus for utilizing carbon dioxide according to claim 1, characterized in that, The ventilation structure includes a ventilation inlet arranged on the side of the packing layer and an exhaust fan arranged at the upper part of the tower body, and an air duct for the exhaust fan to draw air is arranged in the tower body.

3. The apparatus for utilizing carbon dioxide according to claim 2, characterized in that, The tower body is divided into left and right sides, which are separated by a partition board. From top to bottom, the left side of the tower body is successively the heat exchange concentration component, the packing layer, and the carbon dioxide absorption water tank, and the right side of the tower body from top to bottom is the air duct. The exhaust fan is arranged at the upper end of the right side of the tower body, the ventilation inlet is arranged on the left side of the tower body, and a ventilation outlet is arranged on the side of the packing layer opposite to the ventilation inlet. The exhaust fan draws air to form a negative pressure in the packing layer to vaporize and cool the heat-exchanged up-to-standard discharged wastewater.

4. The apparatus for utilizing carbon dioxide according to claim 1, characterized in that, The carbon dioxide absorption water tank includes an air venting tank on the left side and an electric descaling tank on the right side. The air venting tank is communicated with the electric descaling tank to enable the water on both sides to flow back and forth. Heat-exchanged carbon dioxide is introduced into the air venting tank, and an electrode group for electric descaling is arranged in the electric descaling tank.

5. A method for utilizing carbon dioxide of the apparatus for utilizing carbon dioxide according to claim 1, characterized in that, It includes the following steps: 1) Heat exchange concentration: The original carbon dioxide is introduced into the heat exchange tubes, and the original up-to-standard discharged wastewater is sprayed outside the heat exchange tubes, so that the original carbon dioxide exchanges heat with the original up-to-standard discharged wastewater to obtain heat-exchanged carbon dioxide and heat-exchanged up-to-standard discharged wastewater; 2) Cooling concentration: The heat-exchanged up-to-standard discharged wastewater is cooled by ventilation to obtain cooled up-to-standard discharged wastewater; 3) Descaling: The heat-exchanged carbon dioxide is introduced into the cooled up-to-standard discharged wastewater to remove calcium ions and obtain up-to-standard discharged wastewater to be separated by the RO membrane.

6. The method for utilizing carbon dioxide of the apparatus for utilizing carbon dioxide according to claim 5, characterized in that, In step 2), the cooling concentration is to spray the heat-exchanged up-to-standard discharged wastewater from top to bottom onto the packing layer and ventilate the packing layer to cool and concentrate the heat-exchanged up-to-standard discharged wastewater.

7. The method for utilizing carbon dioxide of the apparatus for utilizing carbon dioxide according to claim 5, characterized in that, In step 2), the temperature of the cooled up-to-standard discharged wastewater is 20 - 40 °C, and the flow rate of the cooled up-to-standard discharged wastewater is 3 - 50 t / h.

8. The method for utilizing carbon dioxide of the apparatus for utilizing carbon dioxide according to claim 5, characterized in that, In step 1), the flow rate of the original carbon dioxide during the heat exchange concentration process is 10 - 25 m / s, and the spraying flow rate of the original up-to-standard discharged wastewater is 50 - 500 t / h.

9. The method for utilizing carbon dioxide of the apparatus for utilizing carbon dioxide according to claim 5, characterized in that, In step 1), the temperature of the original carbon dioxide entering the heat exchange tubes is 100 - 300 °C, and the temperature of the original carbon dioxide leaving the heat exchange tubes is 80 - 280 °C; the original temperature of the original up-to-standard discharged wastewater is 10 - 25 °C, and the temperature of the heat-exchanged up-to-standard discharged wastewater is 20 - 40 °C.

10. The method for utilizing carbon dioxide of the apparatus for utilizing carbon dioxide according to claim 5, characterized in that, In step 3), when descaling, an electrode group for electric descaling is set to precipitate calcium carbonate in time.

Images