System for capturing and recovering calcium carbonate through carbon neutralization and emission reduction

Abstract

The invention relates to a system for capturing and recovering calcium carbonate by carbon neutralization and emission reduction, which is used for treating flue gas and fly ash slurry discharged by an incineration plant and a coal-fired power plant containing a thermal power plant, dehydrating the fly ash slurry to separate out a filter cake and filtrate, and generating jet flow and sucking the flue gas in cooperation with a high-efficiency gas-liquid mixer. Lime contained in the carbon dioxide dissolving filtrate is subjected to a neutralization reaction, then dehydration recovery is performed to obtain calcium carbonate, so that the waste treatment amount and cost are reduced, the calcium carbonate can be used as a desulfurizing agent, and the filtrate is subjected to multi-stage circular reaction elutriation in the dehydration process to save time and water and reduce emission; and moreover, a neutralizer is replaced by absorbing the flue gas, so that the cost and the emission of carbon dioxide can be reduced, and environmental protection and sustainable operation of enterprises are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of fly ash washing, filtering and drying, and in particular to a carbon neutral emission reduction and capture and recovery system for calcium carbonate. Background Art

[0002] Incinerators and coal-fired power plants including thermal power plants produce a relatively large amount of fly ash during the burning of garbage or coal. Fly ash contains soluble substances such as potassium, sodium, and chloride ions, as well as insoluble substances such as calcium, silicon, aluminum, and iron, and is considered hazardous industrial waste.

[0003] In the current treatment method for fly ash, the fly ash is first washed with water to dissolve the soluble substances such as potassium, sodium, and chloride ions contained in the fly ash, and the heavy metals are captured by chelating agents. Then, the fly ash is sent to a dehydrator for dehydration to separate the filtrate and the filter cake. However, the filtrate is strongly alkaline (PH value 11-12), so an acid must be added to the filtrate for acid-base neutralization, which increases costs and wastes resources. Therefore, how to solve the above problems is a topic that the relevant industry players are eager to study. Summary of the invention

[0004] The main purpose of the present invention is to dehydrate the fly ash slurry to separate the filter cake and the filtrate, and then use a high-efficiency gas-liquid mixer to generate a jet flow and inhale flue gas, so that carbon dioxide dissolves the lime contained in the filtrate for neutralization reaction, and then dehydrates and recovers calcium carbonate to reduce the amount of waste treatment and cost. The calcium carbonate can be used as a desulfurizer, and the filtrate is further subjected to multi-stage cyclic reaction washing during the dehydration process to save time, water and reduce emissions. In addition, the use of flue gas absorption instead of the use of neutralizers can reduce costs and carbon dioxide emissions, thereby achieving environmental protection and sustainable business operations.

[0005] To achieve the above-mentioned objectives, the carbon neutrality, emission reduction, capture and recovery system of calcium carbonate of the present invention comprises a fly ash supply device, a flue gas supply device, a first dissolving and stirring tank, a temporary stirring tank, a first dehydrator, a first filtrate tank, a first gas-liquid mixer, a second dehydrator and a second filtrate tank, wherein: the fly ash supply device is used to transport fly ash; the flue gas supply device is used to cool and transport flue gas; the first dissolving and stirring tank is connected to the fly ash supply device to receive fly ash slurry and a chelating agent for stirring and dissolving into a first fly ash slurry containing lime; the temporary stirring tank is connected to the first dissolving and stirring tank to receive the first fly ash slurry output by the first dissolving and stirring tank for stirring; the first dehydrator is connected to the temporary stirring tank to receive the first fly ash slurry output by the temporary stirring tank, and then dehydrates and separates a first filter cake and a first filtrate containing the lime; the first filtrate tank receives the first filtrate discharged by the first dehydrator, and the first filtrate tank transports the first The filtrate circulates through the first filtrate tank and the first gas-liquid mixer to generate a jet flow, and the first gas-liquid mixer is connected to the flue gas supply device by a branch, and the flue gas is sucked by the first gas-liquid mixer, so that the carbon dioxide contained in the flue gas is dissolved in the first filtrate to form carbonic acid, and the carbonic acid reacts with the lime contained in the first filtrate to form calcium carbonate; the second dehydrator is connected to the first filtrate tank to receive the first filtrate containing the calcium carbonate output by the first filtrate tank, and then dehydrates and separates the first filtrate to obtain the first calcium carbonate; the second filtrate tank receives the first filtrate dehydrated and discharged by the second dehydrator, and the second filtrate tank conveys the first filtrate to circulate through the first dehydrator, the first filtrate tank, the second dehydrator and the second filtrate tank in sequence, so that the first filtrate circulates to wash and dissolve the lime contained in the first fly ash slurry inside the first dehydrator, and then continues to perform carbon neutralization and dehydrate and separate to obtain the first calcium carbonate.

[0006] The aforementioned carbon neutrality, emission reduction, capture and recovery system for calcium carbonate, wherein a stirring and dissolving tank is connected between the fly ash supply device and the first dissolving and stirring tank, the stirring and dissolving tank receives the fly ash and adds water to stir and dissolve it into the fly ash slurry, and then transports the fly ash slurry into the first dissolving and stirring tank.

[0007] The aforementioned carbon neutrality emission reduction capture and recovery system for calcium carbonate further includes a second dissolving and stirring tank, a third dehydrator, a third filtrate tank, a second gas-liquid mixer, a fourth dehydrator and a fourth filtrate tank, wherein: the second dissolving and stirring tank receives the first filter cake, adds water and crushes it, and then stirs and dissolves it into a second fly ash slurry containing the lime; the third dehydrator is connected to the second dissolving and stirring tank to receive the second fly ash slurry output by the second dissolving and stirring tank, and then dehydrates and separates the second filter cake and the second filtrate containing the lime; the third filtrate tank receives the second filtrate discharged by the third dehydrator, and the third filtrate tank transports the second filtrate to circulate through the third filtrate tank and the second gas-liquid mixer to generate a jet flow, and the second gas-liquid mixer is branched and connected to the flue gas supply device, so as to benefit The flue gas is sucked in by the second gas-liquid mixer, and the carbon dioxide contained in the flue gas is dissolved in the second filtrate to form carbonic acid, and the carbonic acid reacts with the lime contained in the second filtrate to form calcium carbonate; the fourth dehydrator is connected to the third filtrate tank to receive the second filtrate containing the calcium carbonate output by the third filtrate tank, and then dehydrates and separates the second filtrate to obtain the second calcium carbonate; the fourth filtrate tank receives the second filtrate dehydrated and discharged by the fourth dehydrator, and the fourth filtrate tank conveys the second filtrate to circulate sequentially through the third dehydrator, the third filtrate tank, the fourth dehydrator and the fourth filtrate tank, so that the second filtrate circulates to wash and dissolve the lime contained in the second fly ash slurry inside the third dehydrator, and then continues to perform carbon neutralization and dehydration and separation to obtain the second calcium carbonate.

[0008] The aforementioned carbon neutrality, emission reduction, capture and recovery system for calcium carbonate, wherein a stirring and dissolving tank is connected between the fly ash supply device and the first dissolving and stirring tank, the stirring and dissolving tank receives the fly ash and adds water to stir and dissolve it into the fly ash slurry, and then transports the fly ash slurry into the first dissolving and stirring tank, and the fourth filtrate tank branches off and transports the second filtrate into the stirring and dissolving tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a block diagram of the carbon neutrality emission reduction capture and recovery system of calcium carbonate according to the first embodiment of the present invention.

[0010] Figure 2 It is a block diagram of the carbon neutrality emission reduction capture and recovery system of calcium carbonate according to the second embodiment of the present invention.

[0011] Description of Reference Numerals

[0012] 1. Fly ash supply device 12. First calcium carbonate

[0013] 2. Flue gas supply device 13. Recovery tank

[0014] 3. Stirring and dissolving tank 14. Wastewater treatment

[0015] 4. First dissolving and stirring tank 15, second dissolving and stirring tank

[0016] 5. Chelating agent tank 16, third dehydrator

[0017] 6. Temporary storage and stirring tank 17. Filter cake packaging

[0018] 7. First dehydrator 18, third filtrate tank

[0019] 8. First filtrate tank 19, second gas-liquid mixer

[0020] 9. First gas-liquid mixer 20. Fourth dehydrator

[0021] 10. Second dehydrator 21. Fourth filtrate tank

[0022] 11. Second filtrate tank 22. Second calcium carbonate. DETAILED DESCRIPTION

[0023] The technical means and effects of the present invention to achieve the above-mentioned purpose are described below with reference to the following feasible embodiments and accompanying drawings:

[0024] First, see Figure 1 The first embodiment shown in the figure can be clearly seen that the carbon neutral emission reduction capture and recovery calcium carbonate system of the present invention includes a fly ash supply device 1, a flue gas supply device 2, a stirring and dissolving tank 3, a first dissolving and stirring tank 4, a chelating agent tank 5, a temporary stirring tank 6, a first dehydrator 7, a first filtrate tank 8, a first gas-liquid mixer 9, a second dehydrator 10, a second filtrate tank 11 and a recovery water tank 13, wherein:

[0025] The fly ash supply device 1 utilizes a screw conveyor and a metering device (not shown) to meter and transport the fly ash.

[0026] The flue gas supply device 2 uses the flue gas emitted from the chimneys of incineration plants and coal-fired power plants including thermal power plants. The flue gas is cooled by a cooling device and transported by a high-temperature corrosion-resistant blower (not shown).

[0027] The stirring and dissolving tank 3 is connected between the fly ash supply device 1 and the first dissolving and stirring tank 4 . The stirring and dissolving tank 3 receives fly ash and adds water to stir and dissolve it into fly ash slurry, and then transports the fly ash slurry into the first dissolving and stirring tank 4 .

[0028] The first dissolving stirring tank 4 is connected to the stirring dissolving tank 3 and the chelating agent tank 5 respectively to receive the fly ash slurry and the chelating agent for stirring and dissolving to form a first fly ash slurry containing lime.

[0029] The temporary storage stirring tank 6 is connected to the first dissolving stirring tank 4 to receive the first fly ash slurry outputted from the first dissolving stirring tank 4 for stirring.

[0030] The first dehydrator 7 is connected to the temporary storage stirring tank 6 to receive the first fly ash slurry outputted from the temporary storage stirring tank 6 and then dehydrates and separates the first filter cake and the first filtrate containing lime.

[0031] The first filtrate tank 8 receives the first filtrate discharged from the first dehydrator 7, and the first filtrate tank 8 then transports the first filtrate to circulate through the first filtrate tank 8 and the first gas-liquid mixer 9 to generate a jet flow, and the first gas-liquid mixer 9 is connected to the flue gas supply device 2 in a venturi manner, and the first gas-liquid mixer 9 is used to inhale the flue gas, so that the carbon dioxide contained in the flue gas is dissolved in the first filtrate to form carbonic acid, and the carbonic acid reacts with the lime contained in the first filtrate to form calcium carbonate.

[0032] The second dehydrator 10 is connected to the first filtrate tank 8 to receive the first filtrate containing calcium carbonate output by the first filtrate tank 8, and then dehydrates and separates the first filtrate to obtain the first calcium carbonate 12. The second dehydrator 10 can also have a drying function to reduce the moisture content of the first calcium carbonate 12.

[0033] The second filtrate tank 11 receives the first filtrate discharged from the second dehydrator 10 by dehydration. The second filtrate tank 11 conveys the first filtrate to circulate through the first dehydrator 7, the first filtrate tank 8, the second dehydrator 10 and the second filtrate tank 11 in sequence, so that the first filtrate circulates to wash and dissolve the lime contained in the first fly ash slurry inside the first dehydrator 7, and then continues to perform carbon neutralization and dehydration separation to obtain the first calcium carbonate 12, so as to reduce the amount and cost of waste treatment, and the first calcium carbonate 12 can be used as a desulfurizer. The first filtrate is further subjected to multi-stage cyclic reaction washing in the dehydration process to save time, water and reduce emissions, and uses flue gas absorption instead of using neutralizers to reduce costs and carbon dioxide emissions, thereby achieving environmental protection and corporate sustainable operation. Furthermore, the second filtrate tank 11 can be controlled to branch and transport the first filtrate into the recovery tank 13, and then supply it to the stirring and dissolving tank 3 for use. Then the second filtrate tank 11 can be controlled to branch and transport the first filtrate for wastewater treatment 14, and the wastewater is concentrated and crystallized to recover sodium carbonate and sodium bicarbonate to be used as a desulfurizer required for incineration plants and coal-fired power plants including electric heat plants, and the final wastewater can be discharged.

[0034] See also Figure 2 The second embodiment shown in the figure can be clearly seen that the main difference between the second embodiment and the first embodiment is that it further includes a second dissolving stirring tank 15, a third dehydrator 16, a third filtrate tank 18, a second gas-liquid mixer 19, a fourth dehydrator 20 and a fourth filtrate tank 21, wherein:

[0035] The first filter cake sent out by the first dehydrator 7 is ground and pulverized by adding water.

[0036] The second dissolving and stirring tank 15 receives the material after the first filter cake is crushed by adding water, and then stirs and dissolves it into a second fly ash slurry containing a small amount of residual lime.

[0037] The third dehydrator 16 is connected to the second dissolving and stirring tank 15 to receive the second fly ash slurry outputted from the second dissolving and stirring tank 15, and then dehydrates and separates the second filter cake and the second filtrate containing lime, and then the second filter cake can be packaged 17 using a space bag.

[0038] The third filtrate tank 18 receives the second filtrate discharged from the third dehydrator 16. The third filtrate tank 18 transports the second filtrate to circulate through the third filtrate tank 18 and the second gas-liquid mixer 19 to generate a jet flow, and the second gas-liquid mixer 19 is branched and connected to the flue gas supply device 2. The second gas-liquid mixer 19 is used to inhale flue gas, so that the carbon dioxide contained in the flue gas is dissolved in the second filtrate to form carbonic acid, and the carbonic acid reacts with the lime contained in the second filtrate to form calcium carbonate.

[0039] The fourth dehydrator 20 is connected to the third filtrate tank 18 to receive the second filtrate containing calcium carbonate outputted from the third filtrate tank 18 , and then dehydrates and separates the second filtrate to obtain the second calcium carbonate 22 . The fourth dehydrator 20 can also have a drying function to reduce the moisture content of the second calcium carbonate 22 .

[0040] The fourth filtrate tank 21 receives the second filtrate discharged from the fourth dehydrator 20 by dehydration. The fourth filtrate tank 21 conveys the second filtrate to circulate through the third dehydrator 16, the third filtrate tank 18, the fourth dehydrator 20 and the fourth filtrate tank 21 in sequence, so that the second filtrate circulates to wash and dissolve the lime contained in the second fly ash slurry inside the third dehydrator 16, and then continues to perform carbon neutralization and dehydration separation to obtain the second calcium carbonate 22, so as to reduce the amount and cost of waste treatment, and the second calcium carbonate 22 can be used as a desulfurizer, and the second filtrate is further implemented in a multi-stage cyclic reaction washing process during the dehydration process to save time, water and reduce emissions, and absorb flue gas instead of using a neutralizer, which can reduce costs and carbon dioxide emissions, and achieve environmental protection and sustainable business operations. Furthermore, the fourth filtrate tank 21 can control the divergence of the second filtrate to enter the recovery tank 13, and then supply the stirring and dissolving tank 3 for use.

[0041] The above embodiments are only used to illustrate the present invention, but not to limit the present invention. Various simple changes and modifications that can be made by those skilled in the art without departing from the spirit and scope of the present invention should still be included in the following claims of this application.

Claims

1. A carbon neutral emission reduction capture and recovery calcium carbonate system, comprising a fly ash supply device, a flue gas supply device, a first dissolution stirring tank, a temporary storage stirring tank, a first dehydrator, a first filtrate tank, a first gas-liquid mixer, a second dehydrator and a second filtrate tank, wherein: The fly ash supply device is used to transport fly ash; The flue gas supply device is used to cool and transport the flue gas; The first dissolving and stirring tank is connected to the fly ash supply device to receive the fly ash slurry and the chelating agent for stirring and dissolving to form a first fly ash slurry containing lime; The temporary storage stirring tank is connected to the first dissolving stirring tank to receive the first fly ash slurry outputted from the first dissolving stirring tank for stirring; The first dehydrator is connected to the temporary storage stirring tank to receive the first fly ash slurry outputted from the temporary storage stirring tank, and then dehydrates and separates the first filter cake and the first filtrate containing the lime; The first filtrate tank receives the first filtrate discharged from the first dehydrator, and the first filtrate tank conveys the first filtrate to circulate through the first filtrate tank and the first gas-liquid mixer to generate a jet flow, and the first gas-liquid mixer is connected to the flue gas supply device, and the flue gas is sucked by the first gas-liquid mixer, so that the carbon dioxide contained in the flue gas is dissolved in the first filtrate to form carbonic acid, and the carbonic acid reacts with the lime contained in the first filtrate to form calcium carbonate; The second dehydrator is connected to the first filtrate tank to receive the first filtrate containing the calcium carbonate outputted from the first filtrate tank, and then dehydrates and separates the first filtrate to obtain the first calcium carbonate; The second filtrate tank receives the first filtrate discharged from the second dewatering machine, and the second filtrate tank conveys the first filtrate to circulate sequentially through the first dewatering machine, the first filtrate tank, the second dewatering machine and the second filtrate tank, so that the first filtrate circulates to wash and dissolve the lime contained in the first fly ash slurry inside the first dewatering machine, and then continues to perform carbon neutralization and dehydration separation to obtain the first calcium carbonate.

2. According to the carbon neutrality and emission reduction capture and recovery system of calcium carbonate according to claim 1, a stirring and dissolving tank is connected between the fly ash supply device and the first dissolution and stirring tank, and the stirring and dissolving tank receives the fly ash and adds water to stir and dissolve it into the fly ash slurry, and then transports the fly ash slurry into the first dissolution and stirring tank.

3. The carbon neutral emission reduction capture and recovery calcium carbonate system according to claim 1 further comprises a second dissolving and stirring tank, a third dehydrator, a third filtrate tank, a second gas-liquid mixer, a fourth dehydrator and a fourth filtrate tank, wherein: The second dissolving and stirring tank receives the first filter cake, adds water and crushes it, and then stirs and dissolves it into a second fly ash slurry containing the lime; The third dehydrator is connected to the second dissolving and stirring tank to receive the second fly ash slurry outputted from the second dissolving and stirring tank, and then dehydrates and separates the second filter cake and the second filtrate containing the lime; The third filtrate tank receives the second filtrate discharged from the third dehydrator, and the third filtrate tank conveys the second filtrate to circulate through the third filtrate tank and the second gas-liquid mixer to generate a jet flow, and the second gas-liquid mixer is connected to the flue gas supply device, and the flue gas is sucked by the second gas-liquid mixer, so that the carbon dioxide contained in the flue gas is dissolved in the second filtrate to form carbonic acid, and the carbonic acid reacts with the lime contained in the second filtrate to form calcium carbonate; The fourth dehydrator is connected to the third filtrate tank to receive the second filtrate containing the calcium carbonate outputted from the third filtrate tank, and then dehydrates and separates the second filtrate to obtain the second calcium carbonate; The fourth filtrate tank receives the second filtrate discharged from the fourth dewatering machine, and the fourth filtrate tank conveys the second filtrate to circulate sequentially through the third dewatering machine, the third filtrate tank, the fourth dewatering machine and the fourth filtrate tank, so that the second filtrate circulates to wash and dissolve the lime contained in the second fly ash slurry inside the third dewatering machine, and then continues to perform carbon neutralization and dehydration separation to obtain the second calcium carbonate.

4. According to the carbon neutrality and emission reduction capture and recovery system of calcium carbonate according to claim 3, a stirring and dissolving tank is connected between the fly ash supply device and the first dissolving and stirring tank, the stirring and dissolving tank receives the fly ash and adds water to stir and dissolve it into the fly ash slurry, and then transports the fly ash slurry into the first dissolving and stirring tank, and the fourth filtrate tank branches and transports the second filtrate into the stirring and dissolving tank.

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