RU2802727C1 - So2 adsorbent material, production method and use thereof, and method for removing so2 from flue gas containing so2 - Google Patents

Abstract

FIELD: desulfurization.

SUBSTANCE: group of inventions relates to an SO₂ adsorbing material, a method for producing an SO₂ adsorbing material, the use of an SO₂ adsorbing material in the desulfurization area, and a method for removing SO₂ from flue gas containing SO₂. SO₂ adsorbing material is presented comprising carbonized organometallic skeletal material and sulphite deposited on carbonized organometallic skeletal material, and carbonized organometallic skeletal material is a carbonized material obtained by treatment of organometallic skeletal material with carbonization, whereas the introduced amount of sulphite is not more than 10 wt.% based on the total weight of the SO₂ absorbent material. In another embodiment, a method for producing an SO₂ absorbent material is provided, which comprises treating the organometallic framework material with carbonization to remove at least a portion of the metallic elements contained in the organometallic framework material to form a carbonized organometallic framework material; applying sulphite to the carbonized organometallic framework material to form an SO₂ absorbent material; wherein said carbonized organometallic framework material and said sulphite are used in such an amount that the amount of sulphite introduced does not exceed 10 wt% based on the total weight of the SO₂ absorbing material. The use of an SO₂ adsorbent material in a desulfurization field is also presented, and a method for removing SO₂ from an SO₂ containing flue gas is presented, including the step of bringing the SO₂ adsorbing material into contact with the SO₂ containing flue gas to be treated for adsorptive purification.

EFFECT: group of inventions provides SO₂ adsorbing material, which has excellent SO₂ adsorption capacity, excellent physical adsorption capacity in the presence of water vapor. In addition, the present SO₂ adsorbent material can be recycled and reused through desorption and regeneration, whereas the SO₂ adsorption capacity remains at a relatively high level after many adsorption-desorption cycles.

14 cl, 1 dwg, 3 tbl, 13 ex

Description

Cross references to related applications

This application claims priority from 10/31/2019 according to the date of application No. 201911048429.7 filed with the Chinese Patent Office.

Field of technology

The present invention relates to the field of desulfurization, in particular, to an SO ₂ adsorbing material, a method for producing an SO ₂ adsorbing material, an SO ₂ adsorbing material obtained by this method, the use of an SO ₂ adsorbing material in a desulfurization field, and a method for removing SO ₂ from a flue gas containing _SO2 .

State of the art

Fossil fuels (eg coal, oil) contain large amounts of sulfur and their direct combustion results in high levels of SO ₂ in the flue gases. Excessive emissions of SO ₂ cause a number of environmental problems, the formation of acid rain and photochemical smog, and pose a serious danger to human production and everyday life.

The most widely used SO ₂ removal methods at present can be divided into wet desulfurization technology and dry desulfurization technology. Of these, the wet desulfurization method is mainly carried out by contacting the alkaline solution with flue gas, converting SO ₂ into sulfite and sulfate through chemical reactions and dissolving the sulfite and sulfate in water, and further treating the sulfate-containing solution, thereby fulfilling the purpose of desulfurization. In industrially used wet desulfurization technologies, SO ₂ in flue gases can be absorbed with a sodium sulfite solution. In dry process desulfurization technologies, SO ₂ is separated from exhaust gases using the adsorption properties of porous materials, SO ₂ is adsorbed to a saturation state, and then subjected to desorption and regeneration or oxidation to SO ₃ , which is then eluted. In dry flue gas desulfurization modes, which are widely used in industry, SO ₂ is removed through the process of adsorption - oxidation - sulfation - alkaline washing using activated carbon as an adsorption oxidizer.

S-Zorb flue gas in the oil refining industry has a SO ₂ concentration of more than 1% by volume; Considering that the content of SO ₂ in flue gas is relatively high, it is more appropriate to adsorb SO ₂ and obtain sulfur by desorption and recycling of SO ₂ , thereby performing SO ₂ recycling and reuse. However, most of the adsorption materials used in the traditional desulfurization process have oxidizing properties and are prone to oxidize SO ₂ to SO ₃ , so the adsorption materials are not suitable for recycling and reusing SO ₂ in S-Zorb flue gases in the adsorption-desorption process. In addition, S-Zorb flue gas has a low O ₂ content (volume concentration is typically less than 0.1%), so the SO ₂ to SO ₃ oxidation treatment mode is not possible. In addition, with respect to S-Zorb flue gas containing water vapor, the existing adsorption material has low SO ₂ physical adsorption ability, which cannot meet the requirements of practical use.

Therefore, the creation of a new SO ₂ adsorbing material with a high ability for physical adsorption of SO ₂ is of great and practical importance.

Brief description of the invention

The present invention is aimed at overcoming the disadvantages of the prior art that the adsorption capacity of the SO ₂ adsorbent material tends to weaken and its physical adsorption capacity is low in the presence of water vapor.

It has been found that although metal-organic framework (MOF) materials have a developed microporous structure and high specific surface area, these materials contain metal oxides with a metal element as the central unit, and these materials are prone to undergo chemical reactions by adsorption of SO ₂ , and thus , these materials have poor SO ₂ physical adsorption ability, which is not conducive to SO ₂ adsorption-desorption and recycling. Although the carbonized metal-organic framework material obtained after the carbonization process is capable of physical adsorption-desorption of SO ₂ , its SO ₂ adsorption capacity is reduced in the presence of water vapor, especially in the case of S-Zorb flue gases containing water vapor, so the physical adsorption capacity does not meet the requirements.

Extensive innovative research has been carried out and it has been found that a composite material obtained by depositing sulfite (such as sodium sulfite) on a carbonized metal-organic framework material can achieve high physical adsorption of SO ₂ due to the synergy between sulfite and carbonized metal-organic framework material, overcoming the disadvantage of that the _SO2 adsorption capacity can be reduced in the presence of water vapor, and the resulting adsorption material can be desorbed and regenerated for reuse, and exhibits excellent recycling performance, so the present invention is made based on this finding.

To achieve the above object, the first aspect of the present invention provides an SO ₂ adsorbent material that contains a carbonized metal-organic framework material and a sulfite supported on the carbonized metal-organic framework material, wherein the carbonized metal-organic framework material is a carbonized material obtained by treating the metal-organic framework material with carbonization.

The amount of introduced sulfite does not exceed 10 wt. % based on the total mass of SO ₂ adsorbing material.

The second aspect of the present invention relates to a method for producing SO ₂ adsorbent material, which includes the following steps:

(1) treating the metal-organic framework material with carbonization to remove at least a portion of the metal elements contained in the metal-organic framework material to obtain a carbonized metal-organic framework material;

(2) applying sulfite to the carbonized metal-organic framework material to obtain an SO ₂ adsorbing material;

wherein said carbonized metal-organic framework material and said sulfite are used in such an amount that the amount of introduced sulfite does not exceed 10 wt. % based on the total mass of SO ₂ adsorbing material.

In a third aspect of the present invention, there is provided an SO ₂ adsorbent material obtained by the method according to the second aspect.

The fourth aspect of the present invention provides the use of the SO ₂ adsorbing material of the first or third aspect in the field of desulfurization.

A fifth aspect of the present invention provides a method for removing SO ₂ from flue gas containing SO ₂ , the method comprising the following steps:

Contacting the SO ₂ adsorbent material with SO ₂ -containing flue gas to be treated for adsorption purification, wherein said SO ₂ adsorbent material is the SO ₂ adsorbent material according to the first aspect or the third aspect.

The present invention has at least the following advantages over the prior art:

(1) The SO ₂ adsorption material proposed in the present invention has excellent SO ₂ adsorption capacity, which is higher than that of commercially available activated carbon and MOF materials under the same adsorption conditions within the permeation time.

(2) The SO ₂ adsorbent material proposed in the present invention also exhibits excellent physical adsorption ability in the presence of water vapor, its adsorption capacity is not obviously reduced in the presence of water vapor; In addition, the SO ₂ adsorbing material proposed in the present invention can be recycled and reused through desorption and regeneration, and the SO ₂ adsorption capacity still remains at a relatively high level after many adsorption-desorption cycles, so the material is of great importance to solve the problem of adsorption and utilization of SO ₂ from flue gases of the oil refining industry.

Other characteristics and advantages of the present invention are set forth in the following detailed description of preferred embodiments.

Brief description of drawings

In fig. 1 is a graph comparing the results of 30 cycles of adsorption-desorption tests between MOF-5, SO ₂ adsorbent material L1 obtained in Example 1, and SO ₂ adsorbent material D1 obtained in Comparative Example 1.

Detailed description

The ends and any values of the ranges disclosed herein are not limited to the exact ranges or values, but such ranges or values should be understood to include values approximating those ranges or values. With respect to numerical ranges, the end values of different ranges, the end values and individual point values of different ranges, and the individual point values may be combined with each other to produce one or more new numerical ranges, which are to be considered specifically disclosed herein.

As noted previously, a first aspect of the present invention provides an SO ₂ adsorbent material, wherein the SO ₂ adsorbent material comprises a carbonized metal-organic framework material and a sulfite supported on the carbonized metal-organic framework material, wherein the carbonized metal-organic framework material is a carbonized material obtained by treating the metal-organic framework material. carbonization of frame material;

The amount of introduced sulfite does not exceed 10 wt. % based on the total mass of SO ₂ adsorbing material.

To obtain a higher adsorption capacity for SO ₂ , it is preferable that the amount of introduced sulfite is 2-7 wt. % based on the total mass of SO ₂ adsorbing material.

In the present invention, the metal-organic framework material is an organic-inorganic hybrid material having an infinite topological regular porous structure, which is formed from an organic ligand and metal ions through coordination bond coupling.

According to the present invention, preferably the metal-organic framework material is a zinc-based metal-organic framework material, where the zinc-based metal-organic framework material means that the metal element in the metal-organic framework material is elemental zinc.

The metal-organic framework material is preferably at least one material selected from the group consisting of MOF-5, MOF-74, ZIF-8, ZIF-7 and ZIF-20, having a specific surface area of 800-1800 m ² /g and volume pores 0.8-1.2 cm ³ /g. Thus, the interaction of the resulting carbonized metal-organic framework material with sulfites makes it possible to obtain a more desirable effect of physical adsorption-desorption of SO ₂ and facilitates the adsorption and recycling of SO ₂ .

The metal-organic framework material is preferably MOF-5 having a specific surface area of 1500-1700 m ² /g and a pore volume of 1-1.15 cm ³ /g.

The metal-organic framework material preferably contains a metal element in an amount of 20-35 wt. %.

The present invention does not impose any particular limitations on the source of the metal-organic framework material that is commercially available or can be obtained by a metal-organic framework material production process known in the art.

In the present invention, the carbonized metal-organic framework material is a carbonized material obtained by treating the metal-organic framework material with carbonization. The carbonization treatment process serves to reduce the content of metal elements in the metal-organic framework material and increase the specific surface area and pore volume of the material. The carbonized metal-organic framework material obtained by carbonization treatment retains the advantages of a regular porous network topological structure, large specific surface area and developed porous structure of the metal-organic framework material.

For example, MOF-5 material is a porous three-dimensional material with an infinite and regular topological structure, formed by a compound of Zn metal and terephthalic acid, the material has a porosity of 70-80%, the secondary structural units are cubic crystals having a = 25.6690 Å, V = 16913.2 Å, internal diameter 15.2 Å and window size 7.8. As for MOF-5, which has an average pore size of 1.45-1.5 nm, the regular porous network topological structure and high porosity of MOF-5 are maintained after the carbonization process, and the pore volume ratio for different pore sizes is macropores (pore size more than 50 nm): mesopores (pore size 2-50 nm): micropores (pore size less than 2 nm) = 1:(13-15):(5-6), and the porosity is 80-85%.

In another example, ZIF-8 is a porous three-dimensional material formed by a compound of Zn and dimethylimidazole, the material has a topological structure of the SOD configuration, an internal pore size of 11.6 Å, a window of 3.4 Å, and a porosity of 35-40%. As for ZIF-8, which has an average pore size of 1.07-1.15 nm, after the carbonization process the regular porous mesh topological structure of ZIF-8 is maintained, the ratio of pore volumes for different pore sizes is macropores (pores larger than 50 nm): mesopores (pore size in the range of 2-50 nm): micropores (pore size less than 2 nm) = 1:(2-3):(16-18), and the porosity is 50-55%.

Preferably, said carbonized metal-organic frame material has a regular, porous and network topological structure with a bulk density of 0.2-0.35 g/cm ³ , a specific surface area of 1000-2700 m ² /g, and a pore volume of 1-3.8 cm ³ /g and the ratio (macropore volume + mesopore volume)/micropore volume = 0.16-3.5.

More preferably, said carbonized metal-organic frame material has a regular, porous and network topological structure with a bulk density of 0.22-0.33 g/cm ³ , a specific surface area of 1025-2650 m ² /g, and a pore volume of 1.06-3.7 cm ³ /g and the ratio (macropore volume + mesopore volume)/micropore volume = 2.3-3.5.

As used herein, macropores refer to pores with a pore diameter greater than 50 nm, mesopores refer to pores with a pore diameter of 2-50 nm, and micropores refer to pores with a pore diameter less than 2 nm.

Preferably, the content of metal elements in the carbonized metal-organic framework material is 0-0.06 wt. %, preferably 0-0.02 wt. %; more preferably, the carbonized metal-organic framework material obtained after the carbonization treatment does not contain metal elements, but the content of metal elements in the carbonized metal-organic framework material is below the lower limit of analytical detection due to inevitable measurement error.

Herein, the metal element content is determined using an inductively coupled plasma (ICP) analytical test.

Preferably, carbonization is carried out in a protective atmosphere at a carbonization temperature of 900-1150°C for a carbonization time of 5-10 hours.

Preferably, the SO ₂ adsorbing material has a bulk density of 0.2-0.39 g/cm ³ , a specific surface area of 1000-2700 m ² /g, a pore volume of 1-3.7 cm ³ /g and a ratio (macropore volume + mesopore volume) /micropore volume = 0.21-3.5.

More preferably, the SO ₂ adsorbing material has a bulk density of 0.21-0.35 g/cm ³ , a specific surface area of 2000-2650 m ² /g, a pore volume of 2.8-3.7 cm ³ /g, preferably 2.86- 3.62 cm ³ /g, and the ratio (macropore volume + mesopore volume)/micropore volume = 2.3-3.5.

Preferably, the content of the metal element introduced by the carbonized metal-organic framework material into the SO ₂ adsorbing material is 0-0.06 mass. %, preferably 0-0.02 wt. %, based on the weight of the carbonized metal-organic framework material in the SO ₂ adsorbing material; more preferably, the SO ₂ adsorbent material does not contain the metal element contained in the metal-organic framework material (eg, elemental zinc in the zinc-based metal-organic framework material), but the content of the metal element may be below the lower limit of analytical detection due to inevitable measurement error.

In the present invention, the specific surface area, porosity, pore volume and pore volume distribution coefficient of the materials are determined by analytically determining the adsorption-desorption curve using an N ₂ adsorption meter.

Preferably, the sulfite is sodium sulfite and/or potassium sulfite, since it has been found that by using sodium sulfite and/or potassium sulfite supported on a carbonized metal-organic framework material, the synergy of the sulfite and the carbonized metal-organic framework material can provide excellent SO ₂ physical adsorption effect. especially in the presence of water vapor, and the resulting adsorption material also exhibits excellent adsorption effect.

The SO ₂ adsorbent material provided by the present invention can be recycled and reused after desorption treatment, however, the present invention does not particularly limit the desorption treatment conditions, however, in order for the desorbed SO ₂ adsorbent material to maintain the desired adsorption effect, preferably the desorption treatment conditions include: carrying out desorption treatment at a temperature of 110-120°C in an atmosphere of nitrogen gas.

The present invention provides an SO ₂ adsorbing material having a higher SO ₂ adsorption capacity, especially in the presence of water vapor, the SO ₂ adsorbing material can also have excellent physical adsorption-desorption effect in the case of flue gas containing water vapor; the SO ₂ adsorption capacity of the SO ₂ adsorbent material presented in the present invention is higher than that of commercially available activated carbon and MOF materials under the same adsorption conditions within the permeation time; the SO ₂ adsorbent material provided by the present invention can be recycled and reused through desorption and regeneration, and the SO ₂ adsorption capacity still remains at a relatively high level after many adsorption-desorption cycles.

As noted earlier, the second aspect of the present invention relates to a method for producing SO ₂ adsorbent material, which includes the following steps:

(1) treating the metal-organic framework material with carbonization to remove at least a portion of the metal elements contained in the metal-organic framework material to obtain a carbonized metal-organic framework material;

(2) applying sulfite to the carbonized metal-organic framework material to obtain an SO ₂ adsorbent material;

wherein said carbonized metal-organic framework material and said sulfite are used in such an amount that the amount of introduced sulfite does not exceed 10 wt. % based on the total mass of SO ₂ adsorbing material.

In the method according to the second aspect of the present invention, to obtain a higher SO ₂ adsorption capacity, it is preferable to use carbonized metal-organic framework material and sulfite in such an amount that the introduced amount of sulfite into the SO ₂ adsorbing material is 1-7 mass. % based on the total mass of SO ₂ adsorbing material.

According to the present invention, changes in the amount of sulfite introduced are preferably achieved by adjusting the concentration of the sulfite solution.

According to the method of the second aspect of the present invention, preferably the carbonation treatment in step (1) is carried out in a protective atmosphere at a carbonation temperature of 900-1150°C for a carbonation time of 5-10 hours. Under these conditions, 99.94-100 wt. can be removed. % metal element in metal-organic framework material; more preferably, the carbonized metal-organic framework material does not contain a metal element after carbonization treatment.

According to the method of the second aspect of the present invention, the carbonization treatment has the same function as in the previously described first aspect, and the resulting properties of the carbonized metal-organic framework material (eg, metal element content, specific surface area, pore volume) are correspondingly identical to those of the carbonized metal-organic framework material described above in connection with the first aspect, and their description will not be repeated here.

According to the method of the second aspect of the present invention, preferably the protective atmosphere is created by at least one substance selected from the group consisting of nitrogen gas, argon gas, helium gas and neon gas.

According to a preferred embodiment of the present invention, methods for applying sulfite to a carbonized metal-organic framework material in step (2) include impregnating the carbonized metal-organic framework material with a sulfite solution and drying the impregnated carbonized metal-organic framework material to remove the solvent.

Preferably, the sulfite solution has a mass concentration of less than 6%, more preferably 1.2-4%; It has been found that a more desirable insertion effect can be obtained by loading the carbonized organometallic framework material with a sulfite solution having a mass concentration within the specified range.

Preferably the impregnation time is 1-5 hours.

In order to obtain an SO ₂ adsorbing material with better adsorption properties, the impregnation is preferably an equal volume impregnation.

Preferably, drying is carried out in an inert atmosphere, the drying temperature is 100-120°C, and the drying time is 6-10 hours.

According to the invention, the inert atmosphere includes nitrogen gas and an inert gas; the inert atmosphere is preferably provided with at least one substance selected from the group consisting of nitrogen gas, argon gas, helium gas and neon gas.

According to the method of the second aspect of the present invention, the sulfite is preferably sodium sulfite and/or potassium sulfite.

According to the method of the second aspect of the present invention, preferably the metal-organic framework material is selected from zinc-based metal-organic framework materials.

According to the method of the second aspect of the present invention, more preferably, the metal-organic framework material is at least one material selected from the group consisting of MOF-5, MOF-74, ZIF-8, ZIF-7 and ZIF-20 with a specific surface area of 800-1800 m ² /g and pore volume 0.8-1.2 cm ³ /g. Thus, the interaction of the resulting carbonized metal-organic framework material with sulfites makes it possible to obtain a more desirable effect of physical adsorption-desorption of SO ₂ and facilitates the adsorption and recycling of SO ₂ .

According to the method of the second aspect of the present invention, even more preferably, the metal-organic framework material is MOF-5 having a specific surface area of 1500-1700 m ² /g and a pore volume of 1-1.15 cm ³ /g.

The present invention provides a method for producing an SO ₂ adsorbent material having excellent SO ₂ physical adsorption effect by applying sulfite to a carbonized metal-organic framework material, and the operations of the producing method are simple, so the method is important for solving the problem of adsorption and utilization of SO ₂ from flue gases from the oil refining industry.

As noted previously, the third aspect of the invention provides an SO adsorbent₂ material obtained by the method of the second aspect.

The SO ₂ adsorbent material obtained by the method of the present invention has high SO ₂ adsorption capacity, especially in the presence of water vapor, and has excellent SO ₂ adsorption capacity for SO ₂ containing flue gases including water vapor; the material exhibits higher _SO2 adsorption capacity than commercial activated carbon and MOF materials under the same adsorption conditions within permeation time; Moreover, the SO ₂ adsorbing material proposed in the present invention can be regenerated by heating and desorption, and the adsorption capacity still remains at a relatively high level after many adsorption-desorption cycles.

As described previously, the fourth aspect of the present invention provides the use of the SO ₂ adsorbent material in accordance with the first aspect or the third aspect in the field of desulfurization.

The present invention does not impose particular restrictions on a particular operation of use, the operation can be carried out using an existing SO ₂ removal operation in the art, and those skilled in the art should not be construed as limiting the present invention.

As noted previously, a fifth aspect of the present invention provides a method for removing SO ₂ from SO ₂ containing flue gas, the method comprising the following steps:

bringing the SO ₂ adsorbent material into contact with an SO ₂ -containing flue gas to be treated for adsorption purification, wherein said SO ₂ adsorbent material is the SO ₂ adsorbent material of the first aspect or the third aspect.

In the fifth aspect of the invention, the SO ₂ adsorbing material has the same properties as the above SO ₂ adsorbing material, and the properties of the SO ₂ adsorbing material such as specific surface area and pore volume are not repeatedly explained in the present specification.

Preferably, the adsorption treatment conditions include an adsorption temperature of 5-25° C., an adsorption hourly space velocity per unit volume of 100-1000 h ^-1 and an adsorption pressure of 0-0.3 MPa, and more preferably 0.1-0.3 MPa.

In the present invention, the adsorption hourly space velocity per unit volume refers to the amount (volume) of the adsorption gas (SO ₂ -containing flue gas) passing per unit volume of the adsorbent per unit time.

Preferably, the SO ₂ -containing flue gas to be treated has a SO ₂ volume content of more than 1%, more preferably 1-5%; the volumetric content of water vapor is 1-4%.

The SO ₂ -containing flue gas is preferably S-Zorb flue gas from a petrochemical refinery industry.

The present invention provides a desulfurization method having a high adsorption capacity for SO ₂ in flue gas by using the SO ₂ adsorbing material of the present invention, which is effective in physically removing SO ₂ from flue gas and can undergo cyclic adsorption and desorption, so it is of great importance in adsorption and recycling of SO ₂ from flue gases in the oil refining industry.

Unless otherwise stated herein, pressure refers to gauge pressure, and normal pressure is 0 MPa.

The present invention is described in detail with reference to examples.

In the following examples, the raw materials used were commercially available products unless otherwise noted.

All metal-organic framework materials MOF-5, ZIF-8 and MOF-74 are produced in-house according to methods disclosed in the prior art literature (Microporous Mesoporous mater. 84 (2005) 97-104; ACS Catal. 2011, 1, 120-127 J. Am. Chem. Soc. 2005, 127, 5, 1504-1518).

In the following examples, the corresponding properties were obtained using the following methods:

(1) the specific surface area, pore volume and pore volume distribution ratio of the material were determined by analytically determining the adsorption-desorption curve using an N ₂ adsorption meter;

(2) metal element content was determined using ICP analytical test;

(3) the SO ₂ content of the gas was measured with an Emerson X-STREAM instrument;

(4) measurement of the introduced amount was carried out by converting the Na element content of the adsorption material determined by the ICP analytical test;

(5) In the following example, the penetration time was set when the _SO2 concentration at the adsorber outlet reached 50 mg/ ^m3 , and the _SO2 adsorption capacity was calculated based on the following formula:

where Q denotes sulfur capacity (adsorption capacity for SO ₂ ), mg/g; q denotes the total flow rate of the gas mixture at the inlet, l/min; C ₀ denotes the SO ₂ concentration at the inlet, mg/l; C _i denotes the SO ₂ concentration at the outlet for the i-th sample, mg/l; t denotes ie sampling time, min; n denotes the sampling number when adsorption reaches saturation or a specified penetration time; m denotes the introduced amount of said adsorption material, g;

(b) Bulk Density: Calculated and obtained by measuring the volume per unit mass of the adsorption material.

Example 1

The matrix used was MOF-5 material, having a specific surface area of 1655 m ² /g and a pore volume of 1.13 cm ³ /g, and a Zn element content of 31.2 wt. %.

(1) The MOF-5 matrix was carbonized at 1000°C for 6 hours in the presence of nitrogen gas to obtain a carbonized metal-organic framework material having a bulk density of 0.22 g/cm ³ , a specific surface area of 2650 m ² /g, and a pore volume 3.7 cm ³ /g, while the content of the Zn element was 0 wt. % and the ratio (macropore volume + mesopore volume)/micropore volume = 3.2.

(2) The carbonized metal-organic framework material was placed in a sodium sulfite solution having a mass concentration of 3% and impregnated with an equivalent volume for 1 hour, the impregnated material was dried under nitrogen gas at 120°C for 6 hours to obtain _SO2 adsorbent material L1.

According to the measurement results, the resulting SO ₂ adsorbing material L1 had an introduced amount of sodium sulfite of 5 wt. %, bulk density 0.231 g/cm ³ , specific surface area 2426 m ² /g, pore volume 3.27 cm ³ /g, ratio (macropore volume + mesopore volume)/micropore volume = 3.1, and the content of the element Zn was 0 mass. %.

Example 2

The SO ₂ adsorbent material was prepared in the same manner as in Example 1, except that in step (2), the carbonized metal-organic framework material was placed in a sodium sulfite solution having a mass concentration of 1.2% and impregnated at an equivalent volume to obtain SO ₂ adsorbing material L2.

According to the measurement results, the resulting SO ₂ adsorbing material L2 had an introduced amount of sodium sulfite of 1 mass. %, bulk density 0.222 g/cm ³ , specific surface area 2615 m ² /g, pore volume 3.62 cm ³ /g, ratio (macropore volume + mesopore volume)/micropore volume = 3.2, and the content of the element Zn was 0 mass. %.

Example 3

The SO ₂ adsorbent material was prepared in the same manner as in Example 1, except that in step (2), the carbonized metal-organic framework material was placed in a sodium sulfite solution having a mass concentration of 4% and impregnated at an equivalent volume to obtain an adsorbent material. SO ₂ material L3.

According to the measurement results, the resulting SO ₂ adsorbing material L3 had an introduced amount of sodium sulfite of 7 wt. %, bulk density 0.235 g/cm ³ , specific surface area 2320 m ² /g, pore volume 3.05 cm ³ /g, ratio (macropore volume + mesopore volume)/micropore volume = 3.35, and the content of the element Zn was 0 mass. %.

Example 4

The SO ₂ adsorbent material was prepared in the same manner as in Example 1, except that in step (2), the carbonized metal-organic framework material was placed in a sodium sulfite solution having a mass concentration of 5.8%, and was impregnated at an equivalent volume to obtaining SO ₂ adsorbing material L4.

According to the measurement results, the resulting SO ₂ adsorbing material L4 had an introduced amount of sodium sulfite of 10 wt. %, bulk density 0.242 g/cm ³ , specific surface area 2110 m ² /g, pore volume 2.86 cm ³ /g, ratio (macropore volume + mesopore volume)/micropore volume = 3.4, and the content of the element Zn was 0 mass. %.

Example 5

The material used as a matrix was ZIF-8, having a specific surface area of 1150 m ² /g and a pore volume of 0.82 cm ³ /g, and a Zn element content of 30.7 wt. %.

(1) The ZIF-8 matrix was carbonized at 1150°C for 5 hours in the presence of nitrogen gas to obtain a carbonized metal-organic framework material, the resulting carbonized metal-organic framework material had a bulk density of 0.28 g/ ^cm3 , a specific surface area of 1290 ^m2 /g, pore volume 1.27 cm ³ /g, Zn element content 0 wt. % and (macropore volume + mesopore volume)/micropore volume = 0.25.

(2) The carbonized metal-organic framework material was placed in a sodium sulfite solution having a mass concentration of 3% and impregnated with an equivalent volume for 1 hour, the impregnated material was dried under nitrogen gas at 120°C for 6 hours to obtain _SO2 adsorbent material L5.

According to the measurement results, the resulting SO ₂ adsorbing material L5 had an introduced amount of sodium sulfite of 5 mass. %, bulk density 0.294 g/cm ³ , specific surface area 1225 m ² /g, pore volume 1.24 cm ³ /g, (macropore volume + mesopore volume)/micropore volume = 0.255, and the Zn element content was 0 mass . %.

Example 6

The material used as a matrix was MOF-74, having a specific surface area of 852 m ² /g and a pore volume of 1.02 cm ³ /g, and a Zn element content of 29.2 wt. %.

(1) The MOF-74 matrix was carbonized at 900°C for 10 hours in the presence of nitrogen gas to obtain a carbonized metal-organic framework material, the resulting carbonized metal-organic framework material had a bulk density of 0.33 g/ ^cm3 , a specific surface area of 1080 ^m2 /g, pore volume 1.06 cm ³ /g, Zn element content 0 wt. % and (macropore volume + mesopore volume)/micropore volume = 0.22.

(2) The carbonized metal-organic framework material was placed in a sodium sulfite solution having a mass concentration of 3% and impregnated with an equivalent volume for 1 hour, the impregnated material was dried under nitrogen gas at 120°C for 6 hours to obtain _SO2 adsorbent material L6.

According to the measurement results, the resulting SO ₂ adsorbing material L6 had an introduced amount of sodium sulfite of 5 mass. %, bulk density 0.346 g/cm ³ , specific surface area 1025 m ² /g, pore volume 1 cm ³ /g, (macropore volume + mesopore volume)/micropore volume = 0.226, and the Zn element content was 0 wt. %.

Comparative example 1

The matrix used was MOF-5 material, having a specific surface area of 1655 m ² /g and a pore volume of 1.13 cm ³ /g, and a Zn element content of 31.2 wt. %.

The MOF-5 matrix was carbonized at 1000°C for 6 hours in the presence of nitrogen gas to obtain SO ₂ adsorbent material D1.

According to the measurement results, the resulting material D1 had a bulk density of 0.22 g/cm ³ , a specific surface area of 2650 m ² /g, a pore volume of 3.7 cm ³ /g, (macropore volume + mesopore volume)/micropore volume = 3.2, and the Zn element content was 0 wt. %.

Comparative example 2

Commercially produced activated carbon material (with a bulk density of 0.62 g/cm ³ , specific surface area of 865 m ² /g, pore volume of 0.52 cm ³ /g) was placed in a sodium sulfite solution having a mass concentration of 3%, and impregnated with an equivalent volume for 1 hour, the impregnated material was dried under nitrogen gas at 120° C. for 6 hours to obtain SO ₂ adsorbent material D2.

According to the measurement results, the resulting SO ₂ adsorbing material D2 had an introduced amount of sodium sulfite of 5 mass. %, bulk density 0.65 g/cm ³ , specific surface area 820 m ² /g, pore volume 0.5 cm ³ /g, (macropore volume + mesopore volume)/micropore volume = 0.2.

Comparative example 3

The SO ₂ adsorbent material was prepared in the same manner as in Example 1, except that in step (2), the carbonized metal-organic framework material was placed in a sodium sulfite solution having a mass concentration of 6.5%, and was impregnated with an equivalent volume to obtain SO ₂ adsorbing material D3.

According to the measurement results, the resulting SO ₂ adsorbing material D3 had an introduced amount of sodium sulfite of 13.2 wt. %, bulk density 0.25 g/cm ³ , specific surface area 1245 m ² /g, pore volume 1.08 cm ³ /g, (macropore volume + mesopore volume)/micropore volume = 3.55, and the element content Zn was 0 wt. %.

Comparative example 4

The MOF-5 material was directly placed into sodium sulfite solution having a mass concentration of 3%, and subjected to impregnation with an equivalent volume for 1 hour without carbonization treatment, but the MOF-5 material was structurally decomposed and contracted after being placed in the sodium sulfite solution, it was impossible to prepare the adsorbent material and perform the subsequent operation.

Test Case 1

Tests were carried out on the adsorption properties of the SO ₂ adsorbing materials obtained in the Examples and Comparative Examples, respectively.

Here, the SO ₂ -containing flue gas to be purified was an S-Zorb steam-containing flue gas in which the SO ₂ content was 3 vol.% and the water vapor content was 3 vol.%.

The SO ₂ -containing flue gas to be purified as described above was subjected to adsorption purification using the SO ₂ adsorbing materials MOF-5, ZIF-8, MOF-74, activated carbon and the SO ₂ adsorbing materials obtained in the Examples and Comparative Examples.

The adsorption purification conditions included an adsorption temperature of 20°C, an hourly space velocity per unit volume at an adsorption of 800 h ^-1 , an adsorption pressure equal to normal pressure and 0.2 MPa, respectively.

The penetration time was set when the SO ₂ concentration at the adsorber outlet reached 50 mg/m ³ ; specific measurement results are shown in Table 1.

As can be seen from Table 1, the SO ₂ adsorbing materials of the present invention have high SO ₂ adsorption capacity, and their SO ₂ adsorption capacity is higher than that of commercially available activated carbon and MOF materials under the same adsorption conditions within the penetration time; in particular, some of the adsorbent materials have an SO ₂ adsorption capacity that is 2.3 times or more that of commercially available activated carbon or 2 times or more that of MOF materials.

In particular, as shown by comparing Examples 1-4 and Comparative Example 3, the SO ₂ adsorption capacity is significantly reduced when the input amount of sulfite exceeds 10 wt. %; It is especially preferable that the SO ₂ adsorbing material has a higher adsorption capacity when the amount of introduced sulfite (eg sodium sulfite) is 2-7 mass. %.

Test case 2

Tests were carried out on the adsorption properties of the SO ₂ adsorbing materials obtained in the Examples and Comparative Examples, respectively, under various conditions of pressure and temperature.

Here, the SO2 _- containing flue gas to be purified was an S-Zorb steam-containing flue gas in which the _SO2 content was 2 vol.% and the water vapor content was 4 vol.%.

The adsorption purification conditions included hourly space velocity per unit volume at 1000 h ^-1 adsorption, and the adsorption pressure and temperature values are specifically listed below in Table 2.

The penetration time was set when the SO ₂ concentration at the adsorber outlet reached 50 mg/m ³ . In the present description, the test results for the SO ₂ adsorbent materials obtained in Example 1 and Comparative Example 5 are presented as an example, and the specific test results are shown in Table 2 and Table 3, respectively.

As can be seen from a comparison of the results in Table 2 and Table 3, the SO ₂ adsorbent materials of the present invention have a high SO ₂ adsorption capacity.

In addition, as shown in Table 2, the SO ₂ adsorption capacity of the adsorbent material of the present invention can be increased by 1.7 to 3.5 times under conditions consisting of the same temperature and elevated pressure, while the temperature is within 5-25°C at the same pressure does not have a noticeable effect on the adsorption capacity for SO ₂ of the adsorbent material.

Test case 3

The cyclic adsorption-desorption properties of the adsorbent materials obtained in the Examples and Comparative Examples were measured.

Here, the SO2 _- containing flue gas to be purified was an S-Zorb steam-containing flue gas in which the _SO2 content was 5% by volume and the steam content was 4% by volume.

The adsorption treatment conditions included: adsorption temperature of 20°C, hourly adsorption space velocity per unit volume of 400 h ^-1 and adsorption pressure of 0.2 MPa.

The penetration time was set when the SO ₂ concentration at the adsorber outlet reached 50 mg/m ³ .

SO ₂ adsorbing materials after adsorption treatment were subjected to desorption treatment at 120°C in an atmosphere of nitrogen gas and 30 cycles of adsorption-desorption tests were carried out.

In the present description, the results of cyclic adsorption-desorption tests of the material MOF-5, the adsorbent material L1 obtained in Example 1, and the adsorbent D1 obtained in Comparative Example 1 are presented as an example, the specific results are shown in FIG. 1.

As can be seen from Fig. 1, the SO ₂ adsorbing materials presented in the present invention have excellent SO ₂ adsorption capacity, their adsorption capacity is not obviously reduced in the presence of water vapor and exhibit excellent recycling efficiency, and the SO ₂ adsorption capacity can be maintained at 85 mass. % or more of the initial adsorption capacity after 30 cycles of adsorption-desorption tests. In contrast, the SO ₂ adsorption capacity of both the MOF-5 material and the D1 adsorption material obtained in Comparative Example 1 was noticeably and significantly reduced during cyclic testing.

To summarize, the SO ₂ adsorbing materials proposed in the present invention have excellent SO ₂ adsorption capacity, especially under flue gas conditions containing water vapor, their adsorption capacity is not obviously reduced in the presence of water vapor, and they exhibit the required the effect of physical adsorption of SO ₂ in flue gases containing water vapor; the adsorption capacity for SO ₂ is higher than that of commercially produced activated carbon and MOF materials under the same adsorption conditions within the penetration time; In addition, the SO ₂ adsorbing materials provided by the present invention can be regenerated by heating and desorption, and the adsorption capacity still remains at a relatively high level after many adsorption-desorption cycles, for example, the SO ₂ adsorption capacity can be maintained at 85 mass. % or more of the initial adsorption capacity after 30 cycles of adsorption-desorption tests, thus SO ₂ adsorbing materials have a wide application prospect.

Preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to them. Various simple modifications may be made to the technical solutions of the present invention within the technical concept of the present invention, including the combination of individual technical features in any other suitable manner, such simple modifications and combinations thereof are also to be considered as disclosed in the present description, and each of them falls under scope of protection of the present invention.

Claims (19)

1. An SO ₂ adsorbing material containing a carbonized metal-organic framework material and sulfite deposited on the carbonized metal-organic framework material, wherein the carbonized metal-organic framework material is a carbonized material obtained by treating the metal-organic framework material with carbonization, and the introduced amount of sulfite is not more than 10 mass .% based on the total mass of SO ₂ adsorbing material. 2. The SO ₂ adsorbent material according to claim 1, wherein the amount of sulfite introduced is 2-7 wt.% based on the total weight of the SO ₂ adsorbent material, preferably the sulfite is sodium sulfite and/or potassium sulfite. 3. SO ₂ adsorbing material according to claim 1 or 2, in which said carbonized metal-organic frame material has a regular, porous and network topological structure with a bulk density of 0.2-0.35 g/cm ³ and a specific surface area of 1000-2700 m ² /g, pore volume 1-3.8 cm ³ /g and ratio (macropore volume + mesopore volume)/micropore volume = 0.16-3.5; preferably, said carbonized metal-organic frame material has a regular, porous and network topological structure with a bulk density of 0.22-0.33 g/cm ³ , a specific surface area of 1025-2650 m ² /g, and a pore volume of 1.06-3.7 cm ³ /g and the ratio (macropore volume + mesopore volume)/micropore volume = 2.3-3.5. 4. SO ₂ adsorbing material according to any one of claims 1-3, where the SO ₂ adsorbing material has a bulk density of 0.2-0.39 g/cm ³ , a specific surface area of 1000-2700 m ² /g, and a pore volume of 1-3 .7 cm ³ /g and the ratio (macropore volume + mesopore volume)/micropore volume = 0.21-3.5; preferably, the SO ₂ adsorbing material has a bulk density of 0.21-0.35 g/cm ³ , a specific surface area of 2000-2650 m ² /g, a pore volume of 2.8-3.7 cm ³ /g and a ratio (macropore volume + volume mesopores)/micropore volume = 2.3-3.5. 5. The SO ₂ adsorbing material according to any one of claims 1 to 4, wherein the metal-organic framework material is a zinc-based metal-organic framework material; preferably the metal-organic framework material is at least one selected from the group consisting of MOF-5, MOF-74, ZIF-8, ZIF-7 and ZIF-20; preferably the metal-organic framework material is MOF-5 having a specific surface area of 1500-1700 m ² /g and a pore volume of 1-1.15 cm ³ /g. 6. SO ₂ adsorbing material according to any one of claims 1-5, where the carbonization treatment is carried out in a protective atmosphere at a carbonization temperature of 900-1150°C for a carbonization time of 5-10 hours. 7. A method for producing SO ₂ adsorbing material, which includes the following stages: (1) treating the metal-organic framework material with carbonization to remove at least a portion of the metal elements contained in the metal-organic framework material to obtain a carbonized metal-organic framework material; (2) applying sulfite to a carbonized metal-organic framework material to obtain an SO ₂ adsorbing material; wherein said carbonized metal-organic framework material and said sulfite are used in such an amount that the amount of introduced sulfite does not exceed 10 wt.% based on the total weight of the SO ₂ adsorbing material. 8. The method according to claim 7, in which the amount of introduced sulfite is 2-7 wt.% based on the total weight of the SO ₂ adsorbing material. 9. The method according to claim 7 or 8, in which the carbonization treatment in step (1) is carried out in a protective atmosphere at a carbonization temperature of 900-1150°C for a carbonization time of 5-10 hours. 10. The method according to any one of claims 7 to 9, wherein the modes of applying sulfite to the carbonized metal-organic framework material in step (2) include impregnation of the carbonized metal-organic framework material with a sulfite solution and drying the impregnated carbonated metal-organic framework material to remove the solvent; preferably the sulfite solution has a mass concentration of less than 6%; preferably, drying is carried out in an inert atmosphere, the drying temperature is 100-120°C, and the drying time is 6-10 hours. 11. Method according to any one of claims 7 to 10, wherein the sulfite is sodium sulfite and/or potassium sulfite. 12. The method according to any one of claims 7 to 11, in which the metal-organic framework material is selected from zinc-based metal-organic framework materials; preferably the metal-organic framework material is at least one selected from the group consisting of MOF-5, MOF-74, ZIF-8, ZIF-7 and ZIF-20; preferably the metal-organic framework material is MOF-5 having a specific surface area of 1500-1700 m ² /g and a pore volume of 1-1.15 cm ³ /g. 13. SO ₂ adsorbing material obtained by the method according to any one of claims 7-12. 14. Use of SO ₂ adsorbing material according to any one of claims 1 to 6 and 13 in the field of desulfurization. 15. A method for removing SO ₂ from an SO ₂ containing flue gas, comprising the step of bringing an SO ₂ adsorbent material into contact with an SO ₂ containing flue gas to be treated for adsorption purification, wherein said SO ₂ adsorbing material is an SO ₂ adsorbing material according to any from paragraphs 1-6 and 13. 16. The method according to claim 15, in which the adsorption treatment conditions include: adsorption temperature 5-25°C, hourly adsorption volumetric rate per unit volume 100-1000 h ^-1 and adsorption pressure 0-0.3 MPa; preferably the SO ₂ -containing flue gas to be purified contains SO ₂ at a volume content of 1-5% and water vapor at a volume content of 1-4%.