CN111589283A - Method for efficiently removing sulfur dioxide in tail gas - Google Patents
Method for efficiently removing sulfur dioxide in tail gas Download PDFInfo
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- CN111589283A CN111589283A CN202010587402.1A CN202010587402A CN111589283A CN 111589283 A CN111589283 A CN 111589283A CN 202010587402 A CN202010587402 A CN 202010587402A CN 111589283 A CN111589283 A CN 111589283A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/48—Sulfur compounds
- B01D53/50—Sulfur oxides
- B01D53/501—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound
- B01D53/502—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound characterised by a specific solution or suspension
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- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/48—Sulfur compounds
- B01D53/50—Sulfur oxides
- B01D53/501—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound
- B01D53/504—Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound characterised by a specific device
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- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
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Abstract
The invention relates to a method for efficiently removing sulfur dioxide in tail gas, which comprises the following steps: (1) the inlet tail gas is sent into a foam washing pipe after heat exchange and temperature reduction, and is in countercurrent contact reaction with absorption liquid sprayed by a washing nozzle, then, gas-liquid two-phase forward flow flows into a mixing element, the contact reaction is continued, and then, gas-liquid separation is carried out to obtain purified gas and washing liquid; (2) purified gas is sent into an absorption liquid storage tank, and then enters a flue gas heat exchanger for temperature rise and evacuation after being defoamed by a demister arranged at the upper part of the absorption liquid storage tank, and washing liquid is circularly returned to the bottom of the absorption liquid storage tank; (3) and introducing oxidizing air into the bottom of the absorption liquid storage tank, returning a part of the absorption liquid at the bottom of the absorption liquid storage tank as circulating liquid to the washing spray head for recycling, and discharging the other part of the absorption liquid. Compared with the prior art, the invention is suitable for SO2High removal efficiency, process flowThe process is simple, the operation flexibility is large, the occupied area is small, the investment is low, the installation and the maintenance are convenient, and the increasingly strict environmental protection emission requirements can be met.
Description
Technical Field
The invention belongs to the technical field of tail gas purification treatment, and relates to a method for efficiently removing sulfur dioxide in tail gas.
Background
The rapid development of the industry often brings about severe environmental problems, and the national environmental protection administration issues the 2014 national environmental condition bulletin to point out: "the atmospheric environmental pollution of our country still takes the coal-smoke type as the main thing, the main pollutant is sulfur dioxide and smoke dust, the acid rain problem is still serious". SO (SO)2Is the main reason of causing acid rain and haze, and causes great harm to human health. Chinese SO 20152The emission reaches 2157 ten thousand tons, and national SO is obtained in 20202The emission amount reaches 3900 ten thousand tons, the environmental capacity of China for sulfur dioxide is about 1200 ten thousand tons per year, and the environment is not too heavy, so that the flue gas desulfurization is the focus of attention. For SO2Serious pollution phenomenon, China has come out a lot of related SO2Regulatory policies and standards for emission control. 2011 issued by the emission Standard of atmospheric pollutants for thermal power plants (GB13223-2011), the Standard stipulates that a newly-built coal-fired boiler and a boiler SO using oil as fuel2Emission limit of 100mg/m3SO of key area2Has a specific emission limit of 50mg/m3. The emission standard of pollutants for petroleum refining industry (GB 31570-2015) promulgates in 2015. SO in Standard2The emission index is changed from original 960mg/m3The standard is increased to 400mg/m3In particular, the discharge area is increased to 100mg/m3. At present, even some power plants begin to execute the index of ultra-low emission (namely SO)2Emission concentration of not more than 35mg/m3) This requires a desulfurization apparatus having a very high desulfurization efficiency.
At present, domestic and overseas flue gas desulfurization methods can be classified into 3 types, namely dry type, semi-dry type and wet type, and although dry method and semi-dry method desulfurization have simple flow and low investment, solid waste is generated, the desulfurization efficiency is low, and the current emission index cannot be met, while wet method desulfurization is widely applied in industry with higher efficiency, and has various processes, such as limestone-gypsum method, magnesium method, ammonia method, sodium-alkali method, seawater method, double alkali method and the like. But the limestone-gypsum method, the double alkali method and the magnesium method have complex process flows, are easy to block and have high operation cost; the ammonia method is easy to generate ammonia escape, and the smoke plume problem is caused; the seawater method is only applicable to a few areas along the sea. The currently used desulfurization tower mainly comprises a spray tower, a packed tower, a bubble tower and the like, but the spray tower occupies a large area, the gas-liquid two-phase contact mode is a liquid drop contact mode, the contact is not sufficient, the desulfurization efficiency is low, and in order to meet the stricter and stricter emission standard in the future, multilayer spray is needed, so that the manufacturing cost of the desulfurization tower is increased; the gas-liquid two-phase contact mode of the packed tower is a liquid film contact mode, tower internals such as packing and the like need to be installed, the risk of blockage is often caused, the pipeline design is complex, the manufacturing cost is high, the size is large, and the operation and the maintenance are complex. The bubble tower has large resistance and small operation elasticity. Although the wet desulphurization technology and the device have various types, along with the stricter requirements of emission regulations, the research on the desulphurization technology with high efficiency and low cost is urgently needed to solve the problems of large occupied area of equipment, easy blockage, high cost and the like in the existing wet desulphurization technology, which is beneficial to SO2Development of end treatment technology.
Disclosure of Invention
The invention aims to provide a method for efficiently removing sulfur dioxide in tail gas, which is used for removing SO2The method has the advantages of high removal efficiency, simple process flow, large operation flexibility, small occupied area, low investment, convenient installation and maintenance and capability of meeting the increasingly strict environmental protection emission requirement.
The purpose of the invention can be realized by the following technical scheme:
a method for efficiently removing sulfur dioxide in tail gas comprises the following steps:
(1) containing SO2The inlet tail gas is sent into a foam washing pipe after heat exchange and temperature reduction, and is in countercurrent contact reaction with absorption liquid sprayed out by a washing nozzle arranged in the foam washing pipe, then, gas-liquid two-phase forward flow flows into a mixing element, the contact reaction is continued, and then, purified gas and washing liquid are obtained through gas-liquid separation;
(2) purified gas is sent into an absorption liquid storage tank, and then enters a flue gas heat exchanger for temperature rise and evacuation after being defoamed by a demister arranged at the upper part of the absorption liquid storage tank, and washing liquid is circularly returned to the bottom of the absorption liquid storage tank;
(3) and introducing oxidizing air into the bottom of the absorption liquid storage tank, returning a part of the absorption liquid at the bottom of the absorption liquid storage tank as circulating liquid to the washing spray head for recycling, and discharging the other part of the absorption liquid.
Further, in the step (1), the washing nozzle is provided with one stage or multiple stages controlled independently, and when the washing nozzle is provided with multiple stages, the washing nozzle is arranged at intervals along the flowing direction of the inlet tail gas.
Further, the absorption liquid is alkali liquor.
Furthermore, the washing nozzle is also connected with an alkali liquor storage tank through an alkali liquor conveying pipeline, and the alkali liquor storage tank is filled with sodium hydroxide solution with the mass concentration of 20-30%.
Furthermore, the operation air speed in the foam washing pipe is 5-20 m/s, and the liquid-air ratio is 3-30L/Nm3。
Further, heat exchange is carried out between the purified tail gas and the inlet tail gas in the flue gas heat exchanger, the temperature of the purified tail gas in the flue gas heat exchanger is 50-70 ℃ and 150-180 ℃, and the temperature of the inlet tail gas in the flue gas heat exchanger is 260-350 ℃ and 150-200 ℃.
Furthermore, the absorption liquid storage tank is internally provided with a cleaning spray head positioned below the demister, and the cleaning spray head is connected with external industrial water through a cleaning pipeline.
Furthermore, the absorption liquid storage tank is divided into a separation area at the upper part and a liquid collection area at the lower part, the cleaning spray head and the demister are arranged in the separation area, purified gas enters the absorption liquid storage tank from the space between the separation area and the liquid collection area, and cleaning liquid is directly sent back to the liquid collection area.
Further, the pH value of the circulating liquid is controlled to be 6-8;
the liquid density at the bottom of the absorption liquid storage tank is controlled to be 1070 to 1100kg/m3。
Further, the inlet tail gas contains SO2The concentration of (A) is 400-30000 mg/Nm3The preferable concentration is 500 to 20000mg/Nm3More preferably, the concentration is 1000 to 10000mg/Nm3And the like.
Further, the SO in the tail gas is purified2The concentration of the carbon nano tube is 35-100 mg/Nm3The entrainment concentration is 30-50 mg/Nm3。
Further, the inlet tail gas and the purified gas exchange heat at the flue gas heat exchanger.
Compared with the prior art, the invention has the following advantages:
(1) using sodium hydroxide solution and SO2The reaction has simple process flow, high desulfurization efficiency and difficult blockage, and avoids the complex process flows, easy blockage and high operation cost of a limestone-gypsum method, a double alkali method, a magnesium method and the like; the ammonia method is easy to generate ammonia escape, and the problems of smoke plume and the like are caused;
(2) the impact type foam scrubber is used as a desulfurization reactor, gas and liquid in the reactor reversely collide to generate a foam area, gas and liquid in the foam area are in turbulent contact, the contact surface area is large, and the contact surfaces are continuously and rapidly updated, so that the mass transfer effect is enhanced, the desulfurization efficiency is higher, the energy consumption is lower, the manufacturing cost is low, the occupied area is small, and the installation and the maintenance are convenient;
(3) the operation elasticity is large, and the device can adapt to larger SO caused by abnormal working conditions2Fluctuations in concentration and tail gas volume;
(4) the automation degree is high, and the management and maintenance workload is small.
Drawings
FIG. 1 is a process flow diagram of the present invention;
FIG. 2 is a schematic structural view of a mixing element;
FIG. 3 is a schematic sectional view A-A of FIG. 2;
the notation in the figure is:
1 is an alkali liquor storage tank, 2 is an alkali liquor delivery pump, 3 is an alkali liquor delivery pipeline, 4 is an alkali liquor regulating valve, 5 is a pH meter, 6 is a circulating pump, 7 is a circulating liquid delivery main pipeline, 8 is an absorption liquid delivery branch pipeline I, 9 is an absorption liquid delivery branch pipeline II, and 10 is a pipeline containing SO2A high-temperature tail gas pipeline, 11 is a purified gas blow-down pipe, 12 is a flue gas heat exchanger, 13 is a foam washing pipe, 14 is a first-stage spray head, 15 is a second-stage spray head, 16 is a mixing element, 17 is a washing liquid return pipeline, 18 is a communication pipeline, 19 is an absorption liquid storage tank, 20 is a demister, 21 is an industrial water pipeline, 22 is a first cleaning spray head, 23 is a second cleaning spray head, 24 is an industrial water regulating valve, 25 is a liquid level meter, 26 is an oxidation air pipeline, 27 is a density meter, 28 is a waste water regulating valve, and 29 is a sewage discharge pipeline;
1601 is guide vane, 1602 is gaseous phase export, 1603 is the liquid phase export.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.
In the following embodiments or examples, a raw material reagent such as an absorption liquid or a functional component, which is not specifically described, is a commercially available raw material or a conventional component for realizing a corresponding function in the art.
The invention provides a method for efficiently removing sulfur dioxide in tail gas, the process flow of which is shown in figure 1, and the method comprises the following steps:
(1) containing SO2The inlet tail gas is sent into a foam washing pipe 13 after heat exchange and temperature reduction, and is in countercurrent contact reaction with absorption liquid sprayed out by a washing nozzle arranged in the foam washing pipe 13, then, gas-liquid two-phase forward flow flows into a mixing element 16, the contact reaction is continued, and then, purified gas and washing liquid are obtained through gas-liquid separation;
(2) purified gas is sent into an absorption liquid storage tank 19, defoamed by a demister 20 arranged at the upper part of the absorption liquid storage tank 19, enters a flue gas heat exchanger 12, heated and evacuated, and cleaning solution is circularly returned to the bottom of the absorption liquid storage tank 19;
(3) the bottom of the absorption liquid storage tank 19 is filled with oxidation air to absorb SO2The sulfite generated by the post-reaction is oxidized into sulfate (for example, sodium sulfite is oxidized into sodium sulfate), one part of the absorption liquid at the bottom of the absorption liquid storage tank 19 is returned to the washing nozzle as a circulating liquid for recycling, and the other part is discharged.
In a specific embodiment of the present invention, the structure of the mixing element is schematically shown in fig. 2 and fig. 3, a gas-liquid two-phase co-current flow enters the mixing element 16, continues to contact and react, then passes through the gap of the rotatable guide vane 1601, and the gas phase rotates under the action of the guide vane 1604 and then is discharged from the gas phase outlet 1602; the liquid phase is separated from the gas phase by centrifugal force and gravity, and then discharged from the liquid phase outlet 1603.
In a specific embodiment of the present invention, in the step (1), the washing nozzle is provided with one stage or multiple stages controlled independently, and when the washing nozzle is provided with multiple stages, the washing nozzle is arranged at intervals along the flow direction of the inlet tail gas. One-stage or multi-stage simultaneous opening can be selected according to the concentration in the tail gas at the inlet, and meanwhile, as the multi-stage washing nozzles are arranged at intervals, when only one-stage nozzles are opened, the follow-up downstream contact time between the washing nozzles and the absorption liquid can be adjusted according to the positions where the washing nozzles are opened.
In a specific embodiment of the present invention, the absorption liquid is a lye.
In a specific embodiment of the invention, the washing nozzle is further connected with an alkali liquor storage tank 1 through an alkali liquor conveying pipeline 3, and the alkali liquor storage tank 1 is filled with a sodium hydroxide solution with a mass concentration of 20-30%.
In a specific embodiment of the present invention, the operation gas speed in the foam washing pipe 13 is 5-20 m/s, and the liquid-gas ratio is 3-30L/Nm3。
In a specific embodiment of the invention, the purified tail gas and the inlet tail gas exchange heat in the flue gas heat exchanger, the temperatures of the purified tail gas entering and exiting the flue gas heat exchanger are respectively 50-70 ℃ and 150-180 ℃, and the temperatures of the inlet tail gas entering and exiting the flue gas heat exchanger are respectively 260-350 ℃ and 150-200 ℃.
In a specific embodiment of the present invention, a cleaning spray head is further disposed in the absorption liquid storage tank 19 below the demister 20, and the cleaning spray head is further connected to external industrial water through a cleaning pipeline.
In a specific embodiment of the present invention, the absorption liquid storage tank 19 is divided into an upper separation region and a lower collection region, the cleaning nozzles and the demister 20 are disposed in the separation region, the purified gas enters the absorption liquid storage tank 19 from between the separation region and the collection region, and the cleaning liquid is directly sent back to the collection region.
In a particular embodiment of the invention, the pH of the circulating liquid is controlled to 6-8, which is adjusted by newly adding lye from the lye storage tank 1.
In a specific embodiment of the present invention, the liquid density at the bottom of the absorption liquid tank 19 is controlled to be 1070 to 1100kg/m3。
In one embodiment of the present invention, the inlet tail gas (i.e., inlet tail gas) contains SO2The concentration of (A) is 400-30000 mg/Nm3The preferable concentration is 500 to 20000mg/Nm3More preferably, the concentration is 1000 to 10000mg/Nm3And the like.
In a particular embodiment of the invention, the SO in the tail gas is cleaned2The concentration of the carbon nano tube is 35-100 mg/Nm3The entrainment concentration is 30-50 mg/Nm3。
In a specific embodiment of the invention, the COD of the sewage discharged from the bottom of the absorption liquid storage tank 19 is less than or equal to 60 mg/L.
The above embodiments can be implemented individually, or in any combination of two or more.
The above embodiments will be described in more detail with reference to specific examples.
Example 1:
SO-containing from refinery sulfur recovery unit2SO-containing high-temperature (260-300 ℃) tail gas2The high-temperature tail gas pipeline 10 enters a flue gas heat exchanger 12, heat exchange is carried out between the high-temperature tail gas pipeline and desulfurized and purified low-temperature tail gas (50-60 ℃), the raw flue gas enters a foam washing pipe 13 from top to bottom after the temperature of the raw flue gas is reduced to 150-180 ℃, the raw flue gas is in contact reaction with absorption liquid sprayed by a first-stage spray head 14 and/or absorption liquid sprayed by a second-stage spray head 15, then gas-liquid two phases flow downstream and flow together to enter a mixing element 16, the downstream contact reaction is carried out again, gas-liquid separation is carried out after the reaction, and low-temperature purified gas is discharged through a purified gas blow-down pipe 11 after.
The new absorption liquid adopts NaOH solution with the mass concentration of 30 percent, the NaOH solution is respectively sent to the inlets of the first-stage spray heads 14 and/or the second-stage spray heads 15 by the alkali liquor delivery pump 2 through the alkali liquor delivery pipeline 3, the first absorption liquid delivery branch pipelines 8 and the second absorption liquid delivery branch pipelines 9, the circulating liquid at the bottom of the absorption liquid storage tank 19 is delivered to the first-stage spray heads 14 and/or the second-stage spray heads 15 by the circulating pump 6 through the circulating liquid delivery main pipeline 7, the first absorption liquid delivery branch pipelines 8 and the second absorption liquid delivery branch pipelines 9, then, the circulating liquid and the inlet tail gas are collided in a reverse direction, a foam area is generated in the foam washing pipe 13, the gas and the liquid in the foam area are in high-speed turbulent flow contact, the contact surface area is large, and the mass transfer effect is rapidly updated, so as to achieve a higher desulfurization effect. Then the gas phase and the liquid phase flow downstream, after the downstream contact reaction of the mixing element 16, the gas phase and the liquid phase are separated, the gas phase obtained by separation enters an absorption liquid storage tank 19 through a communication pipeline 18 connected with a gas phase outlet of the mixing element 16, and the liquid phase returns to the bottom of the absorption liquid storage tank 19 through a washing liquid return pipeline 17. The upper part of the absorption liquid storage tank 19 is a separation area provided with a demister 20, the lower part is a liquid collection area, the separated liquid is continuously recycled, and gas enters the flue gas heat exchanger 12 to be heated and then is emptied by the purified gas emptying pipe 11 after water mist and foam are removed by the demister 20. The washing shower nozzle is arranged below the demister 20, the demister 20 in the embodiment is provided with two stages, the washing shower nozzle is divided into a first washing shower nozzle 22 and a second washing shower nozzle 23 which are respectively positioned below the two-stage demister 20 and connected with an external industrial water pipeline 21, the demister 20 needs to be regularly washed, soluble and suspended solids are prevented from scaling on blades, and the washing time and frequency of each stage can be adjusted according to actual conditions.
In this embodiment, referring to fig. 2 and fig. 3, the structure of the mixing element 16, a gas-liquid two-phase co-current flow enters the mixing element 16, continues to contact and react, then passes through the gap of the rotatable guide vane 1601, and the gas phase rotates under the action of the guide vane 1604 and then is discharged from the gas phase outlet 1602; the liquid phase is separated from the gas phase by centrifugal force and gravity, and then discharged from the liquid phase outlet 1603.
The inlet tail gas (i.e. the initially entering inlet tail gas) contains SO2The concentration is 500-20000 mg/Nm3SO after treatment2The concentration is 35-50 mg/Nm3. When the concentration of the tail gas is lower, the first-stage spray head 14 or the second-stage spray head 15 is started, and when the concentration of the tail gas is higher, the first-stage spray head and the second-stage spray head are started at the same time.
The liquid level in the absorption liquid storage tank 19 needs to be kept stable during the operation of the system, and the liquid level is controlled by the signal linkage of the liquid level meter 25 and the industrial water regulating valve 24 (namely, the liquid level in the absorption liquid storage tank 19 is detected by the liquid level meter 25, when the liquid level is below a lowest liquid level warning line, the industrial water regulating valve 24 is controlled to be opened to supplement industrial water, and when the liquid level exceeds a highest liquid level warning line, the industrial water regulating valve 24 is controlled to be closed), wherein the highest liquid level does not exceed 700mm of the normal liquid level, and the lowest liquid level is not lower than 500mm of the normal liquid level. In order to keep the desulfurization efficiency, the pH value of the absorption liquid needs to be kept stable during the operation of the system, and the pH value is controlled by signal linkage of a pH meter 5 and an alkali liquor regulating valve 4 (as above, when the pH value is detected to be lower, alkali liquor is supplemented), so that the pH value is kept in the range of 6-7. The density of the absorption liquid is controlled by the signal linkage of the density meter 27 and the waste water adjusting valve 28, so that the density is kept between 1070 kg/m and 1100kg/m3Within the range (i.e., when the density of the circulating fluid reaches a set value, a portion of the circulating fluid is discharged to the sewage treatment system through the sewage line 29). In the system, oxidation air is required to be introduced through an oxidation air pipeline 26 extending into a liquid collecting area at the bottom of the absorption liquid storage tank 19 so as to forcibly oxidize sodium sulfite, so that the COD of the discharged wastewater is less than or equal to 50 mg/L.
By applying the method for efficiently removing sulfur dioxide in tail gas based on the sodium-alkali method, the desulfurization efficiency is more than 98%, and the entrainment concentration of outlet liquid foam is less than 50mg/m3The COD of the discharged wastewater is less than or equal to 60mg/L, the system utilization efficiency is high, the system can run efficiently, stably and continuously, and the requirements of desulfurization efficiency and wastewater discharge indexes are met.
Meanwhile, when the adopted inlet tail gas contains SO2The concentration is replaced by 400-30000 mg/Nm3(i.e., the concentration can be selected within any range of values such as 400, 500, 1000, 5000, 10000, 20000, 30000, etc.), the SO in the corresponding purified exhaust gas after the treatment of the above example 12The concentration can still be processed to 35-100 mg/Nm3And (4) the following steps. This shows that a very large range of SO can be accommodated using the process of this example2The fluctuation of the concentration.
The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.
Claims (10)
1. A method for efficiently removing sulfur dioxide in tail gas is characterized by comprising the following steps:
(1) containing SO2The inlet tail gas is sent into a foam washing pipe after heat exchange and temperature reduction, and is in countercurrent contact reaction with absorption liquid sprayed out by a washing nozzle arranged in the foam washing pipe, then, gas-liquid two-phase forward flow flows into a mixing element, the contact reaction is continued, and then, purified gas and washing liquid are obtained through gas-liquid separation;
(2) purified gas is sent into an absorption liquid storage tank, and then enters a flue gas heat exchanger for temperature rise and evacuation after being defoamed by a demister arranged at the upper part of the absorption liquid storage tank, and washing liquid is circularly returned to the bottom of the absorption liquid storage tank;
(3) and introducing oxidizing air into the bottom of the absorption liquid storage tank, returning a part of the absorption liquid at the bottom of the absorption liquid storage tank as circulating liquid to the washing spray head for recycling, and discharging the other part of the absorption liquid.
2. The method for efficiently removing the sulfur dioxide in the tail gas according to claim 1, wherein in the step (1), the washing nozzle is provided with one stage or multiple stages controlled independently, and when the washing nozzle is provided with multiple stages, the washing nozzle is arranged at intervals along the flow direction of the inlet tail gas.
3. The method for efficiently removing the sulfur dioxide in the tail gas according to claim 1, wherein the absorption liquid is an alkali solution.
4. The method for efficiently removing the sulfur dioxide in the tail gas according to claim 1 or 3, wherein the washing nozzle is further connected with an alkali liquor storage tank through an alkali liquor conveying pipeline, and the alkali liquor storage tank is filled with a sodium hydroxide solution with the mass concentration of 10% -30%.
5. The method for efficiently removing sulfur dioxide from tail gas according to claim 1, wherein the operation gas speed in the foam washing pipe is 5-20 m/s, and the liquid-gas ratio is 3-30L/Nm3。
6. The method for efficiently removing sulfur dioxide from tail gas according to claim 1, wherein the purified tail gas exchanges heat with the inlet tail gas in the flue gas heat exchanger, the temperatures of the purified tail gas in the flue gas heat exchanger are 50-70 ℃ and 150-180 ℃, and the temperatures of the inlet tail gas in the flue gas heat exchanger are 260-350 ℃ and 150-200 ℃.
7. The method for efficiently removing sulfur dioxide from tail gas according to claim 1, wherein a cleaning spray head is further arranged in the absorption liquid storage tank and is positioned below the demister, and the cleaning spray head is further connected with external industrial water through a cleaning pipeline.
8. The method as claimed in claim 1, wherein the absorption liquid storage tank is divided into an upper separation region and a lower collection region, the cleaning nozzles and the demister are disposed in the separation region, the purified gas enters the absorption liquid storage tank from between the separation region and the collection region, and the cleaning liquid is directly sent back to the collection region.
9. The method for efficiently removing the sulfur dioxide in the tail gas according to claim 1, wherein the pH value of the circulating liquid is controlled to be 6-8; the liquid density at the bottom of the absorption liquid storage tank is controlled to be 1070 to 1100kg/m3。
10. The method for efficiently removing sulfur dioxide from tail gas according to claim 1, wherein the inlet tail gas contains SO2The concentration of (A) is 400-30000 mg/Nm3(ii) a Purifying SO in tail gas2The concentration of the carbon nano tube is 35-100 mg/Nm3The entrainment concentration is 30-50 mg/Nm3。
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112495142A (en) * | 2020-11-30 | 2021-03-16 | 铜陵有色金属集团股份有限公司 | System and method for removing pollutants in flue gas collected by sodium sulfide removal thermosol tank |
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Application publication date: 20200828 |