Method for purifying flue gas containing heavy metals

Abstract

The embodiment of the invention provides a method for purifying flue gas containing heavy metals. The flue gas purification method comprises the following steps that flue gas containing heavy metal is subjected to dust removal and pre-cooling treatment, and flue gas A is obtained; washing the obtained flue gas A with alkali liquor, and then cooling the washed flue gas A to obtain low-temperature flue gas B at the temperature of minus zero; and carrying out low-temperature adsorption treatment on the low-temperature flue gas B to obtain regenerated gas C containing nitrogen and sulfur after purification. According to the method for purifying the flue gas containing the heavy metals in the embodiment of the invention, the heavy metals in the flue gas are converted into hydroxide precipitates through alkali liquor washing, and particularly, the adsorption rate of the flue gas to heavy metals such as mercury, selenium and lead can reach 90% or above. In addition, gradient utilization of cooling capacity is facilitated through stepped cooling treatment, energy consumption is reduced, and cooling efficiency is improved. Therefore, the method for purifying the flue gas containing the heavy metals has the advantages that the energy consumption is reduced, and the adsorption efficiency of the heavy metals in the flue gas is improved.

Description

Technical Field

[0001] The invention relates to the technical field of flue gas treatment, and in particular to a method for purifying flue gas containing heavy metals. Background Art

[0002] The large amount of pollutants produced by coal-fired flue gas is one of the important factors that endanger the atmospheric environment and human health. Coal-fired flue gas pollutants can be divided into two categories: main pollutants and other pollutants according to their emission volume and degree of harm. Under normal circumstances, the main pollutants in flue gas include dust, SO2 and NOx, and there are mature control technologies for these pollutants. However, in some special fields, there are also problems of excessive heavy metals in flue gas, such as mercury and lead. In related technologies, high-temperature flue gas is usually directly cooled to approximately 200°C through a cooling tower, and then transported to a flue gas purification tower for high-temperature adsorption purification. However, high-temperature adsorption has the problems of large adsorbent consumption and poor adsorption effect. Summary of the invention

[0003] The present invention is based on the inventor's discovery and understanding of the following facts and problems:

[0004] In order to overcome the problems in high-temperature adsorption, the relevant technology proposes a flue gas low-temperature adsorption technology, which is to cool the flue gas to a low-temperature flue gas below room temperature, for example, and then remove the pollutant components in the flue gas by adsorption. In low-temperature adsorption, the adsorption capacity of the adsorbent is increased exponentially in a low-temperature environment, which greatly improves the adsorption purification rate compared to conventional high-temperature flue gas adsorption, and can achieve near-zero emissions of flue gas. However, the inventors have realized through research that compared with conventional high-temperature adsorption, in the low-temperature adsorption process, the diffusion rate of low-temperature flue gas is lower than that of high-temperature flue gas, which greatly increases the residence time of low-temperature flue gas in the purification tower, resulting in the problem of long purification time, which in turn affects the purification efficiency of the flue gas.

[0005] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, an embodiment of the present invention provides a method for purifying flue gas containing heavy metals. The method for purifying flue gas containing heavy metals has the advantage of improving adsorption efficiency.

[0006] The method for purifying flue gas containing heavy metals according to the embodiment of the present invention comprises the following steps:

[0007] Step 1, dust removal and pre-cooling of flue gas containing heavy metals to obtain flue gas A;

[0008] Step 2, washing the obtained flue gas A with alkali solution, and then sending the washed flue gas A into a multi-stage step cooling spray tower for cooling treatment to obtain low-temperature flue gas B with a temperature below zero;

[0009] Step 3: Send the low-temperature flue gas B to a low-temperature adsorption tower for adsorption treatment to further remove sulfides and halides in the flue gas, obtain purification and regeneration, and generate nitrogen-sulfur regeneration gas C.

[0010] The method for purifying flue gas containing heavy metals in the embodiment of the present invention, through dust removal, alkali solution washing, step cooling spray and low temperature adsorption and other processes, the alkali solution washing can convert the heavy metals therein into hydroxide precipitation, especially the adsorption of heavy metals mercury, selenium and lead can reach more than 90%, the purification effect is very good, and the heavy metal pollution to the environment in the flue gas is greatly reduced. In addition, after the step-by-step cooling treatment, the flue gas temperature is gradually cooled from about 150°C to about -80°C, and when the temperature is graded, when the total temperature of the cooling is constant, the temperature difference between each level is reduced, which is helpful to realize the gradient utilization of cold capacity, reduce energy consumption, and improve cooling efficiency.

[0011] Therefore, the method for purifying flue gas containing heavy metals according to the embodiment of the present invention has the advantages of reducing energy consumption and improving the adsorption efficiency of heavy metals in flue gas.

[0012] In some embodiments, in step 1, the flue gas is first sent to an air premixer for precooling and then sent to a dust collector for dust removal, and the temperature of the flue gas A at the outlet of the air premixer is below 150°. The air premixer has the advantages of improving heat exchange efficiency and low energy consumption.

[0013] In some embodiments, in step 2, the flue gas A is sequentially passed through the first cooling component, the second cooling component, the third cooling component and the fourth cooling component of the multi-stage step cooling spray tower to obtain a low-temperature flue gas B with a temperature of -80°C to -15°C. This avoids the problem of poor heat exchange effect and high energy consumption caused by large temperature difference of step cooling. Therefore, setting a four-stage cooling component is helpful to further realize the utilization of cooling gradient and improve the cooling efficiency of the equipment.

[0014] In some embodiments, the first-stage cooling component cools the flue gas A after alkali solution washing from 80°C to 100°C to 40°C to 50°C; the second-stage cooling component cools the flue gas to 10°C to 15°C; the third-stage cooling component cools the flue gas to -10°C to 0°C; the fourth-stage cooling component cools the flue gas to -80°C to -15°C.

[0015] In some embodiments, in step 2, the alkali solution is at least one of Ca(OH)2 solution, NaOH solution, KOH solution, NaHCO3 solution, Na2CO3 solution, ammonia solution, K2CO3 solution, KHCO3 solution and Ca(HCO3)2 solution, the pH value of the alkali solution is 8 to 11.5, and the temperature of the alkali solution is 20°C to 60°C.

[0016] In some embodiments, in step 3, the temperature of the adsorption treatment is -80°C to -15°C.

[0017] In some embodiments, two low-temperature adsorption towers are provided. When one of the low-temperature adsorption towers is saturated with adsorption, the flue gas is switched to another low-temperature adsorption tower for adsorption treatment, and the two low-temperature adsorption towers are alternately treated in sequence.

[0018] In some embodiments, the saturated adsorbent in the low-temperature adsorption tower is regenerated by heating or vacuum suction.

[0019] In some embodiments, in step 3, the adsorbent used in the adsorption treatment is a low-temperature flue gas adsorbent, which is spherical or cylindrical and includes a breathable outer shell and a plurality of adsorbent particles contained in the breathable outer shell or a plurality of adsorbent particles coated with a breathable membrane. The breathable outer shell is provided with air holes for allowing low-temperature flue gas to enter and exit. The diameter of the adsorbent particles is 1 mm to 10 mm, and the diameter of the adsorbent is 10 mm to 100 mm.

[0020] In some embodiments, the heavy metals in the flue gas include mercury: 1.50 μg / Nm 3 ~3.00μg / Nm 3 , Selenium: 20.00μg / Nm 3 ~40.00μg / Nm 3 , lead: 2.00μg / Nm 3 ~10.00μg / Nm 3 . BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a flow chart of flue gas purification according to one embodiment of the present invention. DETAILED DESCRIPTION

[0022] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0023] Reference below Figure 1 A method for purifying flue gas containing heavy metals according to an embodiment of the present invention is described.

[0024] The method for purifying flue gas containing heavy metals according to the embodiment of the present invention comprises the following steps:

[0025] Step 1, dust removal and pre-cooling of flue gas containing heavy metals to obtain flue gas A;

[0026] Step 2, washing the obtained flue gas A with alkali solution, and then sending the washed flue gas A into a multi-stage step cooling spray tower for cooling treatment to obtain low-temperature flue gas B with a temperature below zero;

[0027] Step 3: Send the low-temperature flue gas B to a low-temperature adsorption tower for adsorption treatment to further remove sulfides and halides in the flue gas, obtain purification and regeneration, and generate nitrogen-sulfur regeneration gas C.

[0028] The method for purifying flue gas containing heavy metals in the embodiment of the present invention, through dust removal, alkali solution washing, step cooling spray and low temperature adsorption and other processes, the alkali solution washing can convert the heavy metals therein into hydroxide precipitation, especially the adsorption of heavy metals mercury, selenium and lead can reach more than 90%, the purification effect is very good, and the heavy metal pollution to the environment in the flue gas is greatly reduced. In addition, after the step-by-step cooling treatment, the flue gas temperature is gradually cooled from about 150°C to about -80°C, and when the temperature is graded, when the total temperature of the cooling is constant, the temperature difference between each level is reduced, which is helpful to realize the gradient utilization of cold capacity, reduce energy consumption, and improve cooling efficiency.

[0029] Therefore, the method for purifying flue gas containing heavy metals according to the embodiment of the present invention has the advantages of reducing energy consumption and improving the adsorption efficiency of heavy metals in flue gas.

[0030] In step 1, the flue gas is first sent to the air premixer for precooling and then sent to the dust collector for dust removal. The temperature of the flue gas A at the outlet of the air premixer is below 150°. It is understood that the air premixer can cool the flue gas.

[0031] The method for purifying flue gas containing heavy metals in the embodiment of the present invention cools the flue gas by first passing the flue gas into an air premixer. The provided air premixer has the advantages of improving heat exchange efficiency and reducing energy consumption.

[0032] Based on the numerical simulation calculation and the pilot platform verification results, the material balance of heavy metals at key nodes is summarized, and the removal principle and removal effect are explained in detail using mercury as an example. The existence forms of Hg in flue gas include particulate mercury (Hgp), oxidized mercury (Hg 2+ ) and elemental mercury (Hg0), accounting for about 3%, 30% and 67% respectively. Among them, particulate mercury (Hgp) is removed along with dust particles during the dust removal process, while oxidized mercury (Hg 2+ ) is easily soluble in water, and more than 80% is discharged along with the flue gas condensate during the contact washing and cooling process. 2+) is adsorbed and removed by the adsorbent under the enhanced effect of low temperature. After this treatment, the remaining content of mercury is less than 5% and the removal rate is higher than 95%. Since the mercury content in the flue gas is low and the adsorbent used for adsorption desulfurization and denitrification is filled in a large amount, it is difficult for mercury to be adsorbed to saturation and will not enter the regeneration gas during the regeneration process. After long-term operation, when the Hg in the adsorbent reaches a certain amount, the adsorbent is replaced, and Hg and the adsorbent are treated together as solid waste.

[0033] Table 1 Pilot platform verification results

[0034] type Before lye washing Spray tower outlet Adsorption tower outlet Removal rate <![CDATA[SO3]]> <![CDATA[27mg / Nm 3 ]]> <![CDATA[17.1mgN / m 3 ]]> <![CDATA[0.23mg / Nm 3 ]]> 99.0％ mercury <![CDATA[1.84μg / Nm 3 ]]> <![CDATA[0.035μg / Nm 3 ]]> <![CDATA[0.024μg / Nm 3 ]]> 98.0％ arsenic Not detected Not detected Not detected - selenium <![CDATA[36.78μg / Nm 3 ]]> - <![CDATA[3.16μg / Nm 3 ]]> 91.4％ lead <![CDATA[4.99μg / Nm 3 ]]> <![CDATA[0.55μg / Nm 3 ]]> <![CDATA[0.46g / Nm 3 ]]> 90.8％

[0035] Table 1 shows that the mercury content before alkali washing is 1.84 μg / Nm 3 At the outlet of the spray tower, the mercury content was reduced to 0.035 μg / Nm 3 After passing through the adsorption tower outlet, the mercury content was reduced to 0.024 μg / Nm 3 The removal rate reached 98%. The selenium content before alkali washing was 36.78μg / Nm 3 After passing through the adsorption tower outlet, the mercury content dropped to 3.16 μg / Nm 3 , the removal rate reached 91.4%.

[0036] It can be seen from the above treatment results that the treatment method according to the present invention can achieve a high removal rate of sulfur-containing pollutants and heavy metals in flue gas, fully meeting the national requirements for pollutant emissions. At the same time, its treatment operation is simple and low-cost, which can be accepted by enterprises.

[0037] Optionally, the air premixer may be a rotary air preheater, which has the advantages of being compact and light in structure.

[0038] In step 2, the flue gas A is sequentially passed into the primary cooling assembly, the secondary cooling assembly, the tertiary cooling assembly and the quaternary cooling assembly of the multi-stage cascade cooling spray tower to obtain low-temperature flue gas B with a temperature of -80°C to -15°C. It can be understood that the multi-stage cascade cooling spray tower includes a primary cooling assembly, a secondary cooling assembly, a tertiary cooling assembly and a quaternary cooling assembly.

[0039] The method for purifying flue gas containing heavy metals in the embodiment of the present invention can reduce the temperature of each cooling by using a primary cooling component, a secondary cooling component, a tertiary cooling component and a quaternary cooling component to cool the flue gas after washing with alkali solution, thereby avoiding the problem of poor heat exchange effect and high energy consumption caused by large temperature difference of step cooling. Therefore, setting a four-stage cooling component is helpful to further realize the utilization of cooling gradient and improve the cooling efficiency of the equipment.

[0040] In addition, the flue gas is cooled to -80°C to -15°C, because the adsorption efficiency of the adsorbent is positively correlated with its temperature, that is, during adsorption, the lower the temperature of the flue gas and the adsorbent, the higher the adsorption efficiency of the adsorbent. However, if the temperature of the adsorbent is set too low, the temperature of the heat exchange medium that needs to be set will be set too low, and the cost of producing the heat exchange medium with a lower temperature will be higher. Therefore, the method for purifying flue gas containing heavy metals in an embodiment of the present invention can be reasonably set according to the requirements of the adsorption efficiency of different adsorbents, taking into account the adsorption efficiency and cost of the adsorbent.

[0041] Furthermore, the flue gas is cooled to -20°C to -15°C, and the nitrogen oxides in the flue gas undergo low-temperature oxidation and adsorption on the surface of adsorbents such as activated carbon, oxidizing the difficult-to-adsorb nitric oxide gas into easily adsorbed nitrogen dioxide gas, which can achieve a hundreds-fold increase in adsorption capacity. In addition, the adsorption capacity of sulfur dioxide, carbon dioxide, heavy metals, etc. is also increased exponentially under low temperature conditions. The method for purifying flue gas containing heavy metals in an embodiment of the present invention absorbs flue gas at low temperatures, which can increase sulfur dioxide, carbon dioxide, heavy metals, etc. in the flue gas exponentially. In particular, for nitric oxide gas that is difficult to adsorb, the treatment efficiency increases exponentially.

[0042] Specifically, the first-stage cooling component cools the flue gas from 80°C to 100°C to 40°C to 50°C; the second-stage cooling component cools the flue gas to 10°C to 15°C; the third-stage cooling component cools the flue gas to -10°C to 0°C; the fourth-stage cooling component cools the flue gas to -80°C to -15°C.

[0043] Furthermore, the primary cooling assembly can be sprayed, and the spray liquid used can be tap water or filtered lake water, river water, etc., which has the advantages of simple source and convenient treatment. The secondary cooling assembly, the tertiary cooling assembly and the quaternary cooling assembly can be cooled by a multi-stage compression refrigerator.

[0044] In step 2, the alkali solution is at least one of Ca(OH)2 solution, NaOH solution, KOH solution, NaHCO3 solution, Na2CO3 solution, ammonia solution, K2CO3 solution, KHCO3 solution and Ca(HCO3)2 solution, the pH value of the alkali solution is 8 to 11.5, and the temperature of the alkali solution is 20°C to 60°C.

[0045] The method for purifying flue gas containing heavy metals in the embodiment of the present invention is to set the alkali solution to at least one of Ca(OH)2 solution, NaOH solution, KOH solution, NaHCO3 solution, Na2CO3 solution, ammonia solution, K2CO3 solution, KHCO3 solution and Ca(HCO3)2. The use of alkali solution to adsorb heavy metals in flue gas has the advantages of low cost, good absorption effect and high absorption efficiency. In addition, the temperature of the alkali solution is 20°C to 60°C, which can also physically cool the flue gas to a certain extent, helping to save overall energy consumption.

[0046] In the step 3, the temperature of the adsorption treatment is -80°C to -15°C.

[0047] The method for purifying flue gas containing heavy metals in an embodiment of the present invention can ensure that the temperature of the flue gas is not increased too much during the adsorption process by setting the temperature of the adsorption treatment to -80°C to -15°C, so that the flue gas can be adsorbed at a low temperature, which helps to maintain the adsorption capacity of the adsorbent, thereby facilitating improving the flue gas adsorption effect.

[0048] There are two low-temperature adsorption towers. When the first low-temperature adsorption tower is saturated with adsorption, the flue gas is switched to the second low-temperature adsorption tower for adsorption treatment, and the two low-temperature adsorption towers are alternately treated in sequence.

[0049] The method for purifying flue gas containing heavy metals in the embodiment of the present invention can facilitate continuous adsorption of flue gas by setting up two low-temperature adsorption towers, thereby preventing the problem of poor adsorption effect caused by adsorbent saturation.

[0050] The saturated adsorbent in the low-temperature adsorption tower is regenerated by heating or vacuum suction, which is conducive to the regeneration of the adsorbent and reduces the cost of flue gas treatment to a certain extent.

[0051] In step 3, the adsorbent used in the adsorption treatment is a low-temperature flue gas adsorbent, which is spherical or cylindrical and includes a breathable outer shell and a plurality of adsorbent particles contained in the breathable outer shell or a plurality of adsorbent particles coated with a breathable membrane on the outside. The breathable outer shell is provided with air holes for the low-temperature flue gas to enter and exit. The diameter of the adsorbent particles is 1 mm to 10 mm, and the diameter of the adsorbent is 10 mm to 100 mm.

[0052] The method for purifying flue gas containing heavy metals in an embodiment of the present invention comprises placing the adsorbent in a breathable shell to form adsorbent particles. On the one hand, this can reduce the generation of dust caused by collisions between adsorbents. On the other hand, it is beneficial to increase the contact area between the flue gas and the adsorbent and improve the air permeability of the adsorbent, which is particularly beneficial for low-temperature adsorption.

[0053] Heavy metals in the flue gas include mercury: 1.50 μg / Nm 3 ~3.00μg / Nm 3 , Selenium: 20.00μg / Nm 3 ~40.00μg / Nm 3 , lead: 2.00μg / Nm 3 ~10.00μg / Nm 3 .

[0054] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0055] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0056] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0058] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0059] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for purifying flue gas containing heavy metals, characterized in that: include: Step 1, dust removal and pre-cooling of flue gas containing heavy metals to obtain flue gas A; Step 2, washing the obtained flue gas A with alkali solution, and then sending the washed flue gas A into a multi-stage step cooling spray tower for cooling treatment to obtain low-temperature flue gas B with a temperature below zero; Step 3: sending the low-temperature flue gas B into a low-temperature adsorption tower for adsorption treatment to obtain purified and regenerated nitrogen-sulfur regeneration gas C.

2. The method for purifying flue gas containing heavy metals according to claim 1, characterized in that: In step 1, the flue gas is first sent to an air premixer for precooling and then sent to a dust collector for dust removal. The temperature of the flue gas A at the outlet of the air premixer is below 150°.

3. The method for purifying flue gas containing heavy metals according to claim 1, characterized in that: In step 2, the flue gas A is sequentially passed into the first cooling component, the second cooling component, the third cooling component and the fourth cooling component of the multi-stage cascade cooling spray tower to obtain a low-temperature flue gas B with a temperature of -80°C to -15°C.

4. The method for purifying flue gas containing heavy metals according to claim 3, characterized in that: The primary cooling component cools the flue gas A after washing with alkali solution from 80°C to 100°C to 40°C to 50°C; The secondary cooling assembly cools the flue gas to 10°C to 15°C; The three-stage cooling assembly cools the flue gas to -10°C to 0°C; The four-stage cooling assembly cools the flue gas to -80°C to -15°C.

5. The method for purifying flue gas containing heavy metals according to claim 1, characterized in that: In step 2, the alkali solution is at least one of Ca(OH)2 solution, NaOH solution, KOH solution, NaHCO3 solution, Na2CO3 solution, ammonia solution, K2CO3 solution, KHCO3 solution and Ca(HCO3)2 solution, the pH value of the alkali solution is 8 to 11.5, and the temperature of the alkali solution is 20°C to 60°C.

6. The method for purifying flue gas containing heavy metals according to claim 1, characterized in that: In the step 3, the temperature of the adsorption treatment is -80°C to -15°C.

7. The method for purifying flue gas containing heavy metals according to claim 1, characterized in that: There are two low-temperature adsorption towers. When one of the low-temperature adsorption towers is saturated with adsorption, the flue gas is switched to the other low-temperature adsorption tower for adsorption treatment, and the two low-temperature adsorption towers are alternately treated in sequence.

8. The method for purifying flue gas containing heavy metals according to claim 7, characterized in that: The saturated adsorbent in the low-temperature adsorption tower is regenerated by heating or vacuum suction.

9. The method for purifying flue gas containing heavy metals according to claim 7, characterized in that: In step 3, the adsorbent used in the adsorption treatment is a low-temperature flue gas adsorbent, which is spherical or cylindrical and includes a breathable outer shell and a plurality of adsorbent particles contained in the breathable outer shell or a plurality of adsorbent particles coated with a breathable membrane. The breathable outer shell is provided with air holes for the low-temperature flue gas to enter and exit. The diameter of the adsorbent particles is 1 mm to 10 mm, and the diameter of the adsorbent is 10 mm to 100 mm.

10. The method for purifying flue gas containing heavy metals according to claim 1, characterized in that: Heavy metals in the flue gas include mercury: 1.50 μg / Nm 3 ~3.00μg / Nm 3 , Selenium: 20.00μg / Nm 3 ~40.00μg / Nm 3 , lead: 2.00μg / Nm 3 ~10.00μg / Nm 3 .

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