CN112642397B

CN112642397B - Composite material, preparation method and application thereof

Info

Publication number: CN112642397B
Application number: CN201910963781.7A
Authority: CN
Inventors: 刘增让; 刘爱华; 李毅; 刘剑利; 徐翠翠; 许金山; 袁辉志; 陶卫东
Original assignee: China Petroleum and Chemical Corp; Qilu Petrochemical Co of Sinopec
Current assignee: China Petroleum and Chemical Corp; Qilu Petrochemical Co of Sinopec
Priority date: 2019-10-11
Filing date: 2019-10-11
Publication date: 2023-06-16
Anticipated expiration: 2039-10-11
Also published as: CN112642397A

Abstract

The invention relates to the technical field of desulfurization, and discloses a composite material, a preparation method and application thereof. The composite material comprises modified active carbon and an active component loaded on the modified active carbon, wherein the modified active carbon comprises active carbon, alkali metal oxide and silicon oxide, and the weight ratio of the active carbon to the alkali metal oxide to the silicon oxide is 100 (0.2-3) (0.8-5); the active component contains iron oxide and rare earth element oxide, and the weight ratio of the active carbon to the iron oxide to the rare earth element oxide is 100 (0.5-5): 1-10. The invention also discloses a preparation method of the composite material and application of the composite material in desulfurization. The composite material of the invention has higher penetrating sulfur capacity as an adsorbent.

Description

Composite material, preparation method and application thereof

Technical Field

The invention relates to the technical field of desulfurization, in particular to a composite material and a preparation method and application thereof.

Background

SO ₂ Is the most main reason for forming acid rain; SO (SO) ₂ Can destroy the physiological function of plants and slow down the growth of crops and trees; human body inhales high concentration SO ₂ The gas can exert a strong stimulating effect on the respiratory tract. SO (SO) ₂ As a main atmospheric pollutant, attention has been paid to the use of the material. It is reported that, taking china as an example, SO ₂ The emission causes 40% of the territorial area to be harmed by acid rain, and the loss caused by the emission is up to 1100 hundred million yuan each year. Thus, pollution control and SO reduction ₂ The emission is an important task for sustainable development of the economic society in China.

SO-containing gas is produced in the flue gas of the industrial heating furnace, the sulfur tail gas and the catalytic cracking regeneration flue gas ₂ With the increasing strictness of environmental regulations, SO ₂ The emission reduction task is urgent. At present, the domestic and foreign flue gas desulfurization technologies are mainly classified into two large categories, the first is a wet method, namely, a certain liquid absorbent, emulsion absorbent or absorption solution is adopted to treat the waste gas, and the second is a dry method, and powdery or granular absorbent, absorbent or catalyst is adopted to remove sulfur dioxide in the flue gas. The most representative of the wet desulfurization technologies is the alkaline desulfurization, such as DuPont ^TM Labsorb technology available from BELCO. The wet desulfurization technology of alkaline washing after flue gas can realize 50mg/m ³ The following lower discharge amount, but the technology generates new secondary pollutant, namely sodium sulfate-containing wastewater, which cannot be directly discharged, and the investment of the reprocessing technology is huge. Currently, the petrochemical industry has completely prohibited the new flue gas alkaline desulfurization process of various devices. The dry desulfurization is simple in operation, The characteristics of low equipment investment, no secondary pollution and the like are rapid in development in recent years, and the desulfurization process is considered as the desulfurization process with the most application prospect. So in recent years, research and development of dry flue gas desulfurization technology are widely paid attention to both home and abroad. If a mature dry desulfurization technology can be adopted for removing sulfur dioxide in flue gas, the SO can be reduced ₂ The emission quantity meets the requirements of various environmental regulations and protects the atmosphere.

The core of the dry desulfurization process is an adsorbent. The dry adsorption desulfurizing adsorbent mainly comprises molecular sieve and active carbon. The active carbon is prepared from coal, wood, fruit shell, etc. by carbonizing at high temperature (300-400 deg.C) and activating at oxygen deficiency (920-960 deg.C). The unique hydrophobicity, non-polarity and heat stability of the activated carbon makes it easy to modify and activate during use, and has unique surface chemistry and void structure, thereby enhancing its loading capacity and adsorption performance. The active carbon has developed internal pores, the surface area of the adsorbable micropores accounts for more than 95 percent of the total surface area, the specific surface area of the active carbon is huge, and the active carbon can effectively adsorb SO ₂ And sulfur-containing compounds. Activated carbon vs SO ₂ The adsorption of (a) is affected by the surface properties such as the morphology and distribution of the pore size. The common active carbon sulfur Rong Xiao has low removal rate and poor precision, and the active carbon is often modified to achieve more ideal desulfurization effect. The chemical property of the surface of the activated carbon is changed to improve the adsorption rate and sulfur capacity of the activated carbon, and the method is a main research direction of active carbon desulfurization at present.

CN106031861a discloses a composite adsorbent for removing acid gases NOx and/or SO from gas mixtures by adsorption and conversion ₂ The composite adsorbent comprises a physical adsorbent and a chemical adsorbent, wherein the physical adsorbent is used for adsorbing acid gas, water molecules and oxygen contained in a gas mixture, the chemical adsorbent is used for reacting with the acid substances in the composite adsorbent, the weight ratio of the physical adsorbent to the chemical adsorbent is 0.1-5.0, and the porosity of the composite adsorbent is 0.2-0.85.

Although the above documents report some adsorbents for removing sulfur compounds and corresponding desulfurization methods, there are problems of low sulfur removal rate (saturated sulfur capacity is usually in the range of 5-10%) and low penetrating sulfur capacity of the desulfurizing agent in specific applications. The limited adsorption capacity makes the adsorbent amount and the purification device bulky, increases the investment cost of the device, and complicates the operation process due to frequent regeneration.

Disclosure of Invention

The invention aims to solve the problem that desulfurization rate and penetrating sulfur capacity are difficult to be compatible in the prior art, and provides a modified activated carbon and composite material, and a preparation method and application thereof.

In order to achieve the above object, the present invention provides a composite material comprising a modified activated carbon and an active component supported on the modified activated carbon, wherein the modified activated carbon comprises an activated carbon, an oxide of an alkali metal and an oxide of silicon and the weight ratio between the activated carbon, the oxide of an alkali metal and the oxide of silicon is 100 (0.2 to 3): (0.8 to 5); the active component contains iron oxide and rare earth element oxide, and the weight ratio of the active carbon to the iron oxide to the rare earth element oxide is 100 (0.5-5): 1-10.

In a second aspect, the present invention provides a method of preparing a composite material, the method comprising:

(1) Kneading, molding, drying and roasting the activated carbon, the alkali metal precursor, the silicon-containing binder and the optional pore-enlarging agent in the presence of a solvent to obtain modified activated carbon, wherein the weight ratio of the activated carbon, the alkali metal precursor and the silicon-containing binder in the obtained modified activated carbon is 100 (0.2-3) to 0.8-5;

(2) Contacting a precursor of an active component with the modified active carbon to load the modified active carbon with the active component, wherein the precursor of the active component contains an iron precursor and a rare earth element precursor, and the precursor of the active component is used in an amount such that the weight ratio of the active carbon to the iron element to the rare earth element in the obtained composite material is 100 (0.5-5): (1-10);

wherein the weight of the alkali metal element, the silicon element, the iron element and the rare earth element is calculated by oxide.

In a third aspect the invention provides a composite material made by the method as described above.

In a fourth aspect, the invention provides the use of a modified activated carbon or composite as described above in adsorptive desulfurization.

In a fifth aspect, the present invention provides a method of desulphurisation, the method comprising: contacting the sulfur-containing gas to be treated with a composite material as described above;

alternatively, the method comprises: preparing a composite material according to the method described above; and then contacting the sulfur-containing gas with the obtained composite material.

A sixth aspect of the present invention provides a system having a desulfurization function, the system comprising:

an oxidation unit for treating sulfur-containing gas and recovering sulfur;

The hydrogenation purification unit is connected with the oxidation unit and is used for carrying out hydrogenation reduction on the oxidized tail gas discharged by the oxidation unit and recovering hydrogen sulfide in a reduction product obtained by hydrogenation reduction;

the incineration unit is used for incinerating the purified tail gas discharged by the hydrogenation purification unit;

an adsorption unit for adsorbing SO-containing gas obtained by incineration ₂ SO in flue gas of (C) ₂ The adsorbent used in the adsorption unit is a composite material as described above.

In a seventh aspect, the present invention provides a method of desulphurisation, the method comprising:

(a) Oxidizing sulfur-containing gas to be treated and recovering sulfur;

(b) Carrying out hydrogenation reduction on the oxidized tail gas and recovering hydrogen sulfide in a reduction product obtained by hydrogenation reduction;

(c) Burning the tail gas after hydrogenation reduction;

(d) SO-containing obtained by incineration ₂ Is contacted with adsorbent to adsorb SO ₂ The adsorbent is a composite material as described above.

Compared with the prior art, the invention has the following advantages:

(1) The composite material of the invention has higher penetrating sulfur capacity when being used as an adsorbent. The specific surface area of the composite material is more than 550m ² The/g and the pore volume are larger than 0.35ml/g, SO that the composite material has good adsorptivity and SO ₂ At removal rates greater than 99%, the breakthrough sulfur capacity is greater than 12% (in preferred embodiments, may be greater than 15%).

(2) The composite material has good regeneration performance.

(3) The composite material has simple preparation process and no secondary pollution in the preparation process.

(4) The composite material can promote the development of a dry desulfurization technology, and provides a clean sulfur-containing waste gas treatment method which has no secondary pollution and meets the environmental protection requirement.

Drawings

FIG. 1 is a schematic diagram of a system according to a preferred embodiment of the present invention;

fig. 2 is a schematic structural view of a system according to another preferred embodiment of the present invention.

Description of the reference numerals

11. First-stage condenser of thermal reaction furnace 12

13. Two-stage condenser of primary catalytic converter 14

15. Three-stage condenser of two-stage catalytic converter 16

17. Liquid sulfur pond 21 hydrogenation reactor

22. Hydrogenation tail gas cooler 23 quench tower

24. Incineration unit of absorption tower 31

41. First absorption tower 42 second absorption tower

111. Tail gas reheater 222 flue gas heat exchanger

Detailed Description

The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.

In the present invention, unless otherwise specified, the volume of the gas is determined in standard conditions (STP) (0 ℃ (273K), 1.01X10) ⁵ Pa); "silicon-to-aluminum ratio" means the molar ratio between elemental silicon and elemental aluminum; "ppm" is the unit of volume concentration.

The modified activated carbon comprises (0.2-3): 0.8-5 weight ratio of activated carbon, alkali metal oxide and silicon oxide.

The weight ratio between the activated carbon and the alkali metal oxide is preferably 100 (0.5-2).

The weight ratio between the activated carbon and the silicon oxide is preferably 100 (1-2.8).

According to the invention, the alkali metal oxide can be common alkali metal oxides with different valence states (such as lithium, sodium, potassium and the like), in particular the common alkali metal precursor is subjected to high-temperature roasting to obtain the oxide. Preferably, the oxide of the alkali metal is K ₂ O and/or Na ₂ O。

According to the invention, the silicon oxide can be common silicon oxide with different valence states, in particular the oxide obtained by roasting common silicon precursor at high temperature. Preferably, the oxide of silicon is SiO ₂ 。

According to a preferred embodiment of the invention, the specific surface area of the modified activated carbon is not less than 600m ² Preferably 650-750m ² /g。

According to a preferred embodiment of the present invention, the modified activated carbon has a pore volume of 0.4ml/g or more, more preferably 0.4 to 0.45ml/g.

The method for preparing the modified activated carbon comprises the following steps: kneading, molding, drying and roasting the activated carbon, the alkali metal precursor, the silicon-containing binder and the optional pore-enlarging agent in the presence of a solvent, wherein the weight ratio of the activated carbon, the alkali metal precursor and the silicon-containing binder in the obtained modified activated carbon is 100 (0.2-3) to 0.8-5, and the weight of the alkali metal element and the silicon element is calculated as oxide.

According to the method for producing a modified activated carbon of the present invention, the precursor of activated carbon and alkali metal is used in such an amount that the weight ratio between activated carbon and alkali metal element in the resulting modified activated carbon is preferably 100 (0.5-2).

According to the method for producing a modified activated carbon of the present invention, the activated carbon and the silicon-containing binder are used in such amounts that the weight ratio between the activated carbon and the silicon element in the resulting modified activated carbon is preferably 100 (1-2.8).

According to the method for preparing the modified activated carbon, the activated carbon can be various common activated carbons, and preferably, the specific surface area of the activated carbon is more than or equal to 700m ² Preferably 700-1000m ² /g。

According to the method for preparing modified activated carbon of the present invention, the alkali metal precursor is not particularly limited, and may be various common alkali metal-containing water-soluble compounds, preferably, the alkali metal precursor is at least one of alkali metal bicarbonate, alkali metal carbonate, alkali metal nitrate and alkali metal sulfate, more preferably, at least one of sodium bicarbonate, potassium bicarbonate, sodium carbonate and potassium carbonate.

According to the method for producing a modified activated carbon of the present invention, there is no particular limitation on the silicon-containing binder, preferably, the silicon-containing binder is silica and/or silicate, more preferably, silica sol and/or water glass. As is well known to those skilled in the art, water glass is commonly referred to as sodium silicate (Na ₂ O·nSiO ₂ ) So that it can provide Si as a silicon-containing binder and Na as an alkali metal precursor, in which case the total amount of sodium silicate and alkali metal (sodium) precursor is such that Na in the resulting product ₂ The content of O is within the above rangeAnd (3) inner part.

According to the method for preparing the modified activated carbon, the pore-expanding agent is a substance which is selectively used, and the specific surface area of the modified activated carbon can be further improved by using the pore-expanding agent. The amount of the pore-expanding agent is not particularly limited, but preferably, the weight ratio of the activated carbon to the pore-expanding agent is 100 (1-10).

According to the method for preparing modified activated carbon of the present invention, the pore-expanding agent may be various existing pore-expanding agents, and preferably, the pore-expanding agent is a substance capable of decomposing at a temperature of not more than 450 ℃. More preferably, the pore-expanding agent is at least one of sesbania powder, polyethylene glycol, starch and citric acid.

According to the method for producing a modified activated carbon of the present invention, there is no particular requirement on the manner of drying, but in order to further improve the properties of the resulting modified activated carbon, drying is performed by a split drying method. Preferably, the drying mode is as follows: drying at 40-80deg.C for 2-4 hr; drying at 100-160deg.C (preferably 110-130deg.C) for 4-6 hr.

According to the method for preparing a modified activated carbon of the present invention, there is no particular requirement for the conditions of calcination, but preferably, the conditions of calcination include: the firing temperature is 400 to 700 ℃, more preferably 450 to 600 ℃. Still preferably, the roasting conditions further include: the calcination time is 3 to 8 hours, more preferably 4 to 6 hours.

According to the method for preparing modified activated carbon of the present invention, there is no particular requirement for the solvent, and may be a common organic solvent and/or inorganic solvent. Preferably, however, the solvent is water. The amount of the solvent used can be controlled by those skilled in the art according to the kneading and molding requirements, and will not be described in detail herein.

According to the method for preparing the modified activated carbon of the present invention, kneading and molding can be performed in a conventional manner, for example, by means of a molding apparatus such as a bar extruder or the like.

The invention also provides the modified activated carbon prepared by the method.

According to one embodiment of the present invention, there is provided a composite material comprisingCharacterized in that the composite material contains active carbon, alkali metal oxide, silicon oxide, iron oxide and rare earth element oxide, wherein the weight ratio of the active carbon, the alkali metal oxide, the silicon oxide, the iron oxide and the rare earth element oxide is 100 (0.2-3): 0.8-5): 0.5-5): 1-10. According to this embodiment of the invention, the composite material may be obtained from all precursors by kneading, shaping, drying and firing. In this embodiment, preferably, the specific surface area of the composite material is greater than or equal to 560m ² Preferably 570-600m ² And/g. Preferably, the pore volume of the composite material is greater than or equal to 0.38ml/g, more preferably 0.38-0.42ml/g. Preferably, the composite material has a saturated sulfur capacity of 15% or more, more preferably 18-20%. Preferably, the penetration sulfur capacity of the composite is greater than or equal to 12%, more preferably 12-15%.

According to another embodiment of the present invention, there is provided a composite material characterized by comprising a modified activated carbon and an active component supported on the modified activated carbon, wherein the modified activated carbon comprises an activated carbon, an oxide of an alkali metal and an oxide of silicon and a weight ratio between the activated carbon, the oxide of an alkali metal and the oxide of silicon is 100 (0.2 to 3): 0.8 to 5; the active component contains iron oxide and rare earth element oxide, and the weight ratio of the active carbon to the iron oxide to the rare earth element oxide is 100 (0.5-5): 1-10. According to this embodiment of the present invention, the modified activated carbon may be prepared first, and then the active component may be supported to obtain the composite material. In this embodiment, preferably, the specific surface area of the composite material is greater than or equal to 550m ² /g, more preferably 560-590m ² And/g. Preferably, the pore volume is ≡ 0.35ml/g, more preferably 0.36-0.4ml/g. Preferably, the saturated sulfur capacity is greater than or equal to 18%, more preferably 20-25%. Preferably, the penetrating sulfur capacity is not less than 12%, more preferably 15.5-16%.

According to the invention, the weight ratio between the activated carbon and the oxide of the alkali metal is preferably 100 (0.5-2), such as 100:0.5, 100:0.6, 100:1, 100:1.2, 100:1.5, 100:1.7, 100:1.8, 100:2 or any value between the above values.

According to the invention, the weight ratio between the activated carbon and the silicon oxide is preferably 100 (1-2.8), such as 100:1, 100:1.5, 100:1.6, 100:1.7, 100:2, 100:2.2, 100:2.5, 100:2.8 or any value between the above values.

According to the invention, the weight ratio between the activated carbon and the iron oxide is preferably 100 (1-2.2), such as 100:1, 100:1.5, 100:1.7, 100:2, 100:2.1, 100:2.2 or any value between the above values.

According to the invention, the weight ratio between the activated carbon and the oxide of the rare earth element is preferably 100 (2-5), such as 100:2, 100:2.2, 100:2.5, 100:3, 100:3.5, 100:3.8, 100:4, 100:4.5, 100:5 or any value between the above values.

According to the composite material of the invention, the alkali metal oxide can be common alkali metal oxides with different valence states (such as lithium, sodium, potassium and the like), in particular the common alkali metal precursor is subjected to high-temperature roasting to obtain the oxide. Preferably, the oxide of the alkali metal is K ₂ O and/or Na ₂ O。

According to the composite material, the silicon oxide can be common silicon oxides with different valence states, in particular the common silicon oxide obtained by roasting a precursor of the silicon at a high temperature. Preferably, the oxide of silicon is SiO ₂ 。

According to the composite material of the invention, the iron oxide can be common iron oxides with different valence states, in particular the common iron precursor obtained by high-temperature roasting. Preferably, the iron oxide is Fe ₂ O ₃ 。

According to the composite material of the present invention, the rare earth element oxide may be a common rare earth element oxide of different valence states (such as lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), yttrium (Y), and scandium (Sc)), particularly an oxide obtained by high-temperature baking a common precursor of a rare earth element. Preferably, the oxide of the rare earth element is CeO ₂ And/or La ₂ O ₃ . Further preferably, the oxide of the rare earth element is CeO ₂ And La (La) ₂ O ₃ And CeO ₂ With La ₂ O ₃ The weight ratio of (2) is 1-3. The preferred rare earth oxide is selected to further enhance the adsorption properties of the composite.

According to one embodiment of the present invention, there is provided a method of preparing a composite material, characterized in that the method comprises: kneading, molding, drying and roasting the active carbon, the alkali metal precursor, the silicon-containing binder, the iron precursor and the rare earth element precursor and the optional pore expanding agent in the presence of a solvent, wherein the weight ratio of the active carbon, the alkali metal precursor, the silicon-containing binder, the iron precursor and the rare earth element precursor in the obtained composite material is 100 (0.2-3): (0.8-5): (0.5-5): (1-10), and the weight of the alkali metal element, the silicon element, the iron element and the rare earth element is calculated as oxide. In this embodiment, the drying mode is preferably: drying at 40-80deg.C for 2-4 hr; and drying at 100-160deg.C (more preferably 110-130deg.C) for 4-6 hr. Preferably, the roasting conditions include: the firing temperature is 400 to 700 ℃, more preferably 450 to 600 ℃. Preferably, the roasting conditions further include: the calcination time is 3 to 8 hours, more preferably 4 to 6 hours.

According to another embodiment of the present invention, there is provided a method of preparing a composite material, characterized in that the method comprises:

In step (1) of this embodiment: the drying mode is preferably as follows: drying at 40-80deg.C for 2-4 hr; and drying at 100-160deg.C (more preferably 110-130deg.C) for 4-6 hr. Preferably, the roasting conditions include: the firing temperature is 400 to 700 ℃, more preferably 450 to 600 ℃. The conditions of the firing further include: the calcination time is 3 to 8 hours, more preferably 4 to 6 hours.

In step (2) of this embodiment, the molecular sieve complex may be loaded with the active component by conventional means, preferably by loading the modified activated carbon with the active component in the following manner: the modified activated carbon is subjected to isovolumetric impregnation with a solution of a precursor containing the active component, the impregnate is dried, and the dried product is calcined.

More preferably, the conditions of the isovolumetric infusion include: the temperature is 5 to 40℃and more preferably 20 to 30 ℃. More preferably, the conditions of the isovolumetric infusion further comprise: the time is 20min-3h, more preferably 0.5-1h.

More preferably, the conditions for drying the impregnate include: the temperature is 80-160℃and more preferably 110-130 ℃. More preferably, the conditions for drying the impregnate further comprise: the time is 2 to 10 hours, more preferably 4 to 6 hours.

More preferably, the conditions under which the dried product is calcined include: the firing temperature is 300 to 500 ℃, more preferably 350 to 450 ℃. More preferably, the conditions under which the dried product is calcined further include: the calcination time is 2 to 10 hours, more preferably 3 to 5 hours.

According to the method of the invention, the precursor of activated carbon and alkali metal is used in an amount such that the weight ratio between activated carbon and alkali metal element in the resulting composite is preferably 100 (0.5-2), such as 100:0.5, 100:0.6, 100:1, 100:1.2, 100:1.5, 100:1.7, 100:1.8, 100:2 or any value between the above values.

According to the method of the invention, the amount of activated carbon and silicon-containing binder is such that the weight ratio between activated carbon and silicon element in the resulting composite is preferably between 100 (1-2.8), such as 100:1, 100:1.5, 100:1.6, 100:1.7, 100:2, 100:2.2, 100:2.5, 100:2.8 or any value between the above values.

According to the method of the invention, the amount of the precursor of activated carbon and iron is such that the weight ratio between activated carbon and elemental iron in the resulting composite is preferably between 100 (1-2.2), such as 100:1, 100:1.5, 100:1.7, 100:2, 100:2.1, 100:2.2 or any value between the above values.

According to the method of the invention, the precursor of activated carbon and rare earth element is used in an amount such that the weight ratio between activated carbon and rare earth element in the resulting composite is preferably 100 (2-5), such as 100:2, 100:2.2, 100:2.5, 100:3, 100:3.5, 100:3.8, 100:4, 100:4.5, 100:5 or any value between the above values.

According to the method for preparing the composite material, the activated carbon can be various common activated carbons, and preferably, the specific surface area of the activated carbon is more than or equal to 700m ² Preferably 700-1000m ² /g。

According to the method of producing a composite material of the present invention, the alkali metal precursor is not particularly limited, and may be various common alkali metal-containing water-soluble compounds, preferably, the alkali metal precursor is at least one of alkali metal hydrogencarbonate, alkali metal carbonate, alkali metal nitrate and alkali metal sulfate, more preferably, at least one of sodium hydrogencarbonate, potassium hydrogencarbonate and potassium carbonate.

According to the method of preparing a composite material of the present invention, there is no binder containing siliconIn particular, preferably, the silicon-containing binder is silica and/or silicate, more preferably silica sol and/or water glass. As is well known to those skilled in the art, water glass is commonly referred to as sodium silicate (Na ₂ O·nSiO ₂ ) So that it can provide Si as a silicon-containing binder and Na as an alkali metal precursor, in which case the total amount of sodium silicate and alkali metal (sodium) precursor is such that Na in the resulting product ₂ The content of O is within the above range.

According to the method for preparing the composite material, the pore-expanding agent is a substance which is selectively used, and the specific surface area of the composite material can be further improved by using the pore-expanding agent. The amount of the pore-expanding agent is not particularly limited, but preferably, the weight ratio of the activated carbon to the pore-expanding agent is 100 (1-10).

According to the method of preparing a composite material of the present invention, the pore-expanding agent may be various existing pore-expanding agents, and preferably, the pore-expanding agent is a substance capable of decomposing at a temperature of not more than 450 ℃. More preferably, the pore-expanding agent is at least one of sesbania powder, polyethylene glycol, starch and citric acid.

According to the method of preparing a composite material of the present invention, the precursor of iron may be various common water-soluble compounds containing iron. Preferably, the precursor of iron is a soluble iron salt, preferably iron nitrate and/or chloride.

According to the method for preparing a composite material of the present invention, the precursor of the rare earth element may be various existing water-soluble compounds containing the rare earth element, preferably, the precursor of the rare earth element is a soluble rare earth metal salt, more preferably, a nitrate of the rare earth metal and/or a chloride of the rare earth metal.

Further preferably, the rare earth element precursor contains a cerium precursor and a lanthanum precursor and the cerium precursor and the lanthanum precursor are used in such an amount that the weight ratio of cerium element to lanthanum element in the resulting composite is 1 to 3. As previously mentioned, the cerium precursor is preferably cerium nitrate and/or cerium chloride; the lanthanum precursor is preferably lanthanum nitrate and/or lanthanum chloride.

According to the method for preparing a composite material of the present invention, there is no particular requirement for the solvent, and may be a common organic solvent and/or inorganic solvent. Preferably, however, the solvent is water. The amount of the solvent used can be controlled by those skilled in the art according to the kneading and molding requirements, and will not be described in detail herein.

According to the method of preparing a composite material of the present invention, kneading and molding may be performed in a conventional manner, for example, by means of a molding apparatus such as a bar extruder or the like.

The invention also provides a composite material made by the method described above.

The invention also provides the application of the modified activated carbon or the composite material in adsorption desulfurization, especially in the case of samples with lower sulfur content (such as sulfur dioxide content not higher than 0.2% by volume (namely 6000 mg/m) ³ ) Such as flue gas) for adsorption desulfurization.

The invention also provides a desulfurization method, which is characterized by comprising the following steps: contacting the sulfur-containing gas to be treated with a composite material as described above;

The desulfurization method according to the present invention is particularly suitable for removal of sulfur in a sample having a low sulfur content, and therefore, preferably, the sulfur dioxide content in the sulfur-containing gas is not higher than 0.2 vol%. In another aspect, when the sulfur dioxide content in the sulfur-containing gas is greater than 0.2% by volume, the method preferably further comprises reducing the sulfur dioxide content in the sulfur-containing gas to less than 0.2% by volume prior to contacting the composite material.

According to the desulfurization method of the present invention, there is no particular requirement for the conditions of the contact, but preferably, the conditions of the contact include: the temperature is 100-150 ℃. Preferably, the contacting conditions further comprise: the gas volume space velocity is 1500-2000h ^-1 。

According to the invention, the composite material not only has good adsorptivity, but also has excellent regeneration performance. Thus, the method further comprises: regenerating the composite material. There is no particular requirement for the method of regeneration, and for example, the regeneration may be thermal regeneration and/or water-washing regeneration. The composite material of the present invention may be thermally regenerated and/or water-washed for regeneration using conventional conditions.

More preferably, the thermal regeneration mode is a gas purge, and the conditions of the gas purge include: the gas volume space velocity is 1000-1500h ^-1 The temperature is 150-250deg.C, and the purge gas is inactive gas (such as nitrogen).

More preferably, the conditions for the water-washing regeneration include: the liquid hourly space velocity is 0.5 to 1.5h ^-1 The temperature is 25-40 ℃.

According to the desulfurization method, the sulfur-containing gas is at least one of petroleum refining industrial heating furnace flue gas, sulfur tail gas and catalytic cracking regeneration flue gas.

The invention also provides a system with a desulfurization function, which is characterized in that the system comprises:

an oxidation unit for treating sulfur-containing gas and recovering sulfur;

According to the system of the invention, in order to facilitate regeneration of the composite material in the adsorption unit, the adsorption unit comprises an inlet and an outlet for regenerant, thereby facilitating the introduction of heat source or water wash into the adsorption unit for regeneration of the composite material.

In order to achieve continuous operation of the system according to the present invention, it is preferable that the adsorption unit includes at least two adsorption towers (e.g., a first adsorption tower 41 and a second adsorption tower 42),for alternative use in continuous adsorption incineration of SO-containing products ₂ SO in flue gas of (C) ₂ . When the composite material is regenerated by thermal regeneration, as shown in fig. 1, hot gas (such as hot nitrogen) may be introduced from the bottom of the adsorption tower, and the generated regenerated gas is discharged from the top of the adsorption tower, and may be further introduced into the oxidation unit for reprocessing. When the composite material is regenerated by means of water washing regeneration, as shown in fig. 2, water washing water can be introduced from the top of the adsorption tower, and the generated regenerated dilute acid is discharged from the bottom of the adsorption tower, and can be further introduced into an oxidation unit for reprocessing.

According to the system of the invention, the oxidation unit can comprise a liquid sulfur tank 17 and a thermal reaction furnace 11, a primary condenser 12 and a catalytic converter which are connected in sequence, wherein the liquid sulfur tank 17 is connected with the primary condenser 12 and the catalytic converter and is used for collecting cooled liquid sulfur. For more efficient sulfur recovery, it is preferable that the oxidation unit includes a liquid sulfur tank 17 and a thermal reaction furnace 11, a primary condenser 12, a primary catalytic converter 13, a secondary condenser 14, a secondary catalytic converter 15, and a tertiary condenser 16 connected in this order, and the liquid sulfur tank 17 is connected to the primary condenser 12, the secondary condenser 14, and the tertiary condenser 16, respectively, for collecting cooled liquid sulfur.

According to the system of the present invention, the hydrogenation purification unit may comprise a hydrogenation reactor 21, a hydrogenated tail gas cooler 22, a quench tower 23 and an absorption tower 24, which are connected in sequence. The oxidized tail gas discharged from the oxidation unit is subjected to hydrogenation reduction in a hydrogenation reactor 21, then enters a hydrogenation tail gas cooler 22 and a quenching tower 23 to be cooled, and then enters an absorption tower 24 to absorb hydrogen sulfide in the reduction product.

According to the system of the invention, the incineration unit may be an incinerator and/or a catalytic incineration reactor.

According to the system of the invention, the oxidation unit, the hydrogenation purification unit and the incineration unit are used for reducing the content of sulfur dioxide in the sulfur-containing gas, and the adsorption unit provided with the adsorption material is used for further reducing the content of sulfur dioxide.

The invention also provides a desulfurization method, which is characterized by comprising the following steps:

(a) Oxidizing sulfur-containing gas to be treated and recovering sulfur;

(c) Burning the tail gas after hydrogenation reduction;

According to the present invention, in step (d), there is no particular requirement for the conditions of the contact, but preferably, the conditions of the contact include: the temperature is 100-150 ℃. Preferably, the contacting conditions further comprise: the gas volume space velocity is 1500-2000h ^-1 。

According to the invention, the composite material not only has good adsorptivity, but also has excellent regeneration performance. Thus, the method further comprises regenerating the adsorbent. There is no particular requirement for the method of regeneration, and for example, the regeneration may be thermal regeneration and/or water-washing regeneration. The composite material of the present invention may be thermally regenerated and/or water-washed for regeneration using conventional conditions.

The time for regeneration can be selected by those skilled in the art as long as the sulfur capacity of the regenerated composite material can be restored to 95% or more of the original state.

According to the present invention, the oxidation in step (a) is not particularly limited as long as sulfur can be obtained by subjecting a sulfur-containing gas to the claus reaction. For example, the manner of oxidation may be: the sulfur-containing gas is subjected to combustion, primary cooling and catalytic reaction in sequence.

Preferably, the conditions of combustion include: the temperature is 900-1400 ℃, and the residence time is 2-3s. In the present invention, "residence time" means the residence time of the sulfur-containing gas in the combustion vessel, i.e., the time from the entry of the gas into the furnace to the exit of the gas, i.e., the reaction time of the gas.

Preferably, the primary cooling conditions are such that the temperature of the cooled gas is 120-180 ℃.

Preferably, the conditions of the catalytic reaction include: the catalyst is alumina-based catalyst and/or titanium oxide-based catalyst, and the gas volume space velocity is 500-1000h ^-1 The temperature is 200-350 ℃.

More preferably, the catalytic reaction is performed in such a manner that a primary catalytic reaction, a secondary cooling, a secondary catalytic reaction and a tertiary cooling are sequentially performed. Further preferably, the conditions of the primary catalytic reaction include: the catalyst is alumina-based catalyst and/or titanium oxide-based catalyst, and the gas volume space velocity is 600-800h ^-1 The temperature is 290-330 ℃. Further preferably, the conditions of the secondary cooling are such that the temperature of the cooled gas is 130-160 ℃. Further preferably, the conditions of the secondary catalytic reaction comprise that the catalyst is an alumina-based catalyst, and the gas volume space velocity is 600-800h ^-1 The temperature is 220-250 ℃. Further preferably, the conditions of the three stages of cooling are such that the temperature of the cooled gas is 130-160 ℃.

In the invention, the main component of the alumina-based catalyst is Al ₂ O ₃ Specific surface area is more than or equal to 350m ² Per g, pore volume ≡ 0.45ml/g, can be obtained commercially, for example, from LS-02 catalyst available from Shandong Qilu chemical industry Co., ltd. The main component of the titanium oxide-based catalyst is TiO ₂ Specific surface area is more than or equal to 180m ² Per g, pore volume ∈0.3ml/g, can be obtained commercially, for example, from LS-981 catalyst available from Shandong Qilu chemical industry Co., ltd.

According to the present invention, in step (b), the hydrogenation reducing conditions may include: the hydrogenation catalyst is Co-Mo series tail gas hydrogenation catalyst, and the gas volume space velocity is 500-1000h ^-1 The temperature is 220-350 ℃. Excellent (excellent)Optionally, the method for recovering the hydrogen sulfide in the reduction product obtained by hydrogenation reduction is as follows: reducing the temperature of the reduced product obtained by hydrogenation reduction to 30-40 ℃, and absorbing hydrogen sulfide in the reduced product by using amine liquid. The concentration of ammonia in the amine liquid may be 20-50 wt%.

In the invention, co-Mo series tail gas hydrogenation catalyst can be prepared by modifying Al ₂ O ₃ Claus tail gas low-temperature hydrogenation catalyst taking cobalt, molybdenum and the like as active metal components as carriers and having specific surface area more than or equal to 200m ² /g, may be obtained commercially, for example, from LSH-02 catalyst available from Shandong Qilu chemical industry Co., ltd. Co-Mo series tail gas hydrogenation catalyst can be modified Al ₂ O ₃ Catalyst special for claus tail gas hydrogenation with cobalt and molybdenum as active metal components and with specific surface area not less than 300m ² /g, can be obtained commercially, for example, from LS-951T catalyst available from Shandong Qilu chemical industry Co., ltd.

According to the invention, in step (c), the incineration conditions may comprise a temperature of 600-800 ℃ and a residence time of 2-3s.

According to the invention, in step (c), the incineration may be in a conventional incineration manner. Preferably, the incineration mode is catalytic incineration, and the conditions of the catalytic incineration include: the catalyst is a catalytic incineration catalyst containing iron and vanadium, the temperature is 250-350 ℃, and the space velocity is 500-1000h ^-1 . The catalytic incineration catalyst containing iron and vanadium comprises the following specific components: fe (Fe) ₂ O ₃ 2-8 wt%, V ₂ O ₅ 1-4 wt% and white carbon black as the rest.

According to the invention, CO in the sulfur-containing gas ₂ Is 3-5% of SO ₂ Is 20-1000ppm by volume, NOx is 20-150ppm by volume, O ₂ Is 3-5% of H ₂ The content of O is 3-10 wt%.

According to the invention, the method is implemented in a system as described above.

The present invention will be described in detail by examples. In the following examples:

activated carbon was purchased from su zhou carbon cyclone activated carbon limited;

the alkaline silica sol is purchased from silicon chemical industry limited company in Qingdao;

The polyethylene glycol has a molecular weight of 1900-2200, and is purchased from the company of Yatai joint chemical industry Co., ltd;

the molecular weight of the sesbania powder is 20.6 ten thousand, and the sesbania powder is purchased from a plant gum factory in Lanken county in Henan province;

the molecular weight of the starch is 5.5 ten thousand, and the starch is purchased from Shandong Hengren industrial and trade Co., ltd;

SiO in water glass ₂ The content was 26.5% by weight, purchased from the mussel-port city, dishing chemical industry, ltd;

the model of the strip extruder is ZYDJ-30, and the manufacturer is a Zibo Chengcheng mechanical Co., ltd;

the element composition measuring method is an X-ray fluorescence method, and specific detection is referred to GB/T30905-2014;

the detection method of the specific surface area and the pore volume is referred to GB/T6609.35-2009.

Example 1

This example is intended to illustrate the composite (or adsorbent) of the present invention and its method of preparation.

Weighing 925g with specific surface area of 906m ² The three components are uniformly mixed to form a material A, namely/g coconut shell activated carbon, 32.67g sodium bicarbonate with 99 weight percent of purity and 28g polyethylene glycol with 99 weight percent of purity.

66.67g of alkaline silica sol (SiO ₂ The content is 30 wt%) and the silica sol is dissolved in 360g of deionized water, and uniformly stirred to prepare the adhesive.

Adding binder into the material A, extruding and molding on an extruder to obtain

The resultant long-strip material was dried at 60℃for 3 hours, dried at 120℃for 5 hours, and calcined at 550℃for 4 hours to obtain a modified activated carbon (or adsorbent carrier), and the specific surface area and pore volume were measured, and the results are shown in Table 4.

45.43g of ferric nitrate (Fe (NO) ₃ ) ₃ ) 26.58g lanthanum nitrate hexahydrate (La (NO) ₃ ) ₃ ·6H ₂ O), 50.45g cerium nitrate hexahydrate (Ce (NO) ₃ ) ₃ ·6H ₂ O) dissolving in deionized water, uniformly stirring to form a stable solution, fixing the volume according to the addition amount of the adsorbent carrier to obtain an active component impregnating solution, impregnating the adsorbent carrier at 25 ℃ for 1h according to an equal volume impregnating method, drying the impregnated material at 120 ℃ for 6 h, and roasting at 400 ℃ for 4h to obtain the adsorbent, wherein the measurement results of the element composition of the adsorbent are shown in Table 2, and the measurement results of the specific surface area and the pore volume are shown in Table 4.

Examples 2 to 11

An adsorbent was prepared according to the respective steps and conditions of example 1, except that the composition, preparation conditions or impregnation solution concentration were changed, specific preparation conditions are shown in Table 1, and the contents of each metal oxide and activated carbon in the finally prepared adsorbent product are shown in Table 2, and the measurement results of specific surface area and the like are shown in Table 4.

TABLE 1

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TABLE 2

Examples numbering	Na ₂ O	SiO ₂	Fe ₂ O ₃	CeO ₂	La ₂ O ₃	Activated carbon
							Example 1	1	2	1.5	2	1	Allowance of
Example 2	1	2	1	1	1	Allowance of
							Example 3	1	2	2	3	1	Allowance of
Example 4	1	1	1.5	2	2	Allowance of
							Example 5	0.5	2	1.5	2.5	1	Allowance of
Example 6	1.5	2.5	1.5	1.5	1.5	Allowance of
							Example 7	1	1.5	1.5	2	1.5	Allowance of
Example 8	1	1	1.5	3	3	Allowance of
							Example 9	0.5	2	1.5	0.5	1	Allowance of
Example 10	(K ₂ O)1	2	2.5	2	1	Allowance of
							Example 11	(K ₂ O)1	2	0.5	2	1	Allowance of

Example 12

Mixing ratio surface area of 906m ² Coconut activated carbon/g, sodium bicarbonate with a purity of 99 wt%, polyethylene glycol with a purity of 99 wt%, alkaline silica Sol (SiO) ₂ 30 wt.%), ferric nitrate, lanthanum nitrate hexahydrate, cerium nitrate hexahydrate and deionized water, the amount of polyethylene glycol was 2g, the amount of deionized water was 12g, and the amounts of the other components were such that the weight ratio among the activated carbon, alkali metal element, silicon element, iron element and rare earth element in the resulting adsorbent was the same as in example 1, relative to 100g of activated carbon. The obtained mixture was extruded on an extruder to obtain a 3-5mm×10mm long material, which was then dried at 60℃for 3 hours, dried at 120℃for 5 hours, and calcined at 550℃for 4 hours to obtain an adsorbent, and the specific surface area was measured as shown in Table 4.

Example 13

Mixing ratioSurface area of 906m ² Coconut activated carbon/g, sodium bicarbonate with a purity of 99 wt%, polyethylene glycol with a purity of 99 wt%, alkaline silica Sol (SiO) ₂ 30 wt.%), ferric nitrate, lanthanum nitrate hexahydrate, cerium nitrate hexahydrate and deionized water, the amount of polyethylene glycol was 5g, the amount of deionized water was 12g, and the amounts of the other components were such that the weight ratio of active carbon, alkali metal element, silicon element, iron element and rare earth element in the resulting adsorbent was the same as in example 5. The obtained mixture was extruded on an extruder to obtain a 3-5mm×10mm long material, which was then dried at 60℃for 3 hours, dried at 120℃for 5 hours, and calcined at 550℃for 4 hours to obtain an adsorbent, and the specific surface area was measured as shown in Table 4.

Example 14

An adsorbent was prepared according to the various procedures and conditions of example 1, except that polyethylene glycol was replaced with equal weight of cellulose.

Comparative examples 1 to 6

An adsorbent was prepared according to the respective steps and conditions of example 1 except that the impregnating solution concentration was changed so that the respective contents of metal oxide and activated carbon in the finally prepared adsorbent product are shown in table 3, and the measurement results of specific surface area and the like are shown in table 4.

TABLE 3 Table 3

Numbering device	Na ₂ O	SiO ₂	Fe ₂ O ₃	CeO ₂	La ₂ O ₃	Activated carbon
							Comparative example 1	1	2	0	2	1	Allowance of
Comparative example 2	1	2	1	0	1.5	Allowance of
							Comparative example 3	1	2	2	3	0	Allowance of
Comparative example 4	1	2	1.5	0	0	Allowance of
							Comparative example 5	1.5	0	1.5	1.5	1.5	Allowance of
Comparative example 6	0	1.5	1.5	2	1.5	Allowance of

Comparative examples 7 to 9

An adsorbent was prepared following the various steps and conditions of example 1, except that ferric nitrate was replaced with equal weights (calculated as metal oxide) of copper nitrate, manganese nitrate and zinc nitrate, respectively.

Comparative example 10

An adsorbent was prepared following the various steps and conditions of example 1, except that lanthanum nitrate hexahydrate and cerium nitrate hexahydrate were replaced with nickel nitrate of equal weight (as metal oxide).

Comparative example 11

An adsorbent was prepared following the various steps and conditions of example 1, except that the alkaline silica sol was replaced with an equal weight of concentrated sulfuric acid.

Test example 1

The adsorbents prepared in examples and comparative examples were evaluated for adsorption activity:

The reactor of the micro-reactor was made of stainless steel pipe with an inner diameter of 20mm, and the reactor was placed in an incubator. The loading amount of the adsorbent is 10ml, and quartz sand with the same granularity is filled at the upper part for mixing and preheating. Analysis of reactor inlet and outlet gases using a morphological sulfur chromatograph manufactured by AC companySO ₂ Is contained in the composition.

The chromatographic operating conditions were as follows:

chromatographic column: agilent 7890B

A detector: antek 7090 (SCD)

Chromatographic column: the length of the stainless steel column is 30m, the inner diameter is 0.32mm, and the thickness of the liquid film is 4 mu m; liquid film specification PDMS-1

Column temperature: 250 DEG C

Detector temperature: 950 DEG C

Gasification chamber temperature: 275 DEG C

Carrier gas (N) ₂ ) Flow rate: 90ml/min;

sample injection amount: 1 mu L

The inlet gas volume composition is CO ₂ 3 vol%, SO ₂ 0.03 vol% (900 mg/m) ³ )、H ₂ O3 by volume, the balance being N ₂ The gas volume space velocity is 1750h ^-1 The reaction temperature was 120 ℃.

The adsorbent pair SO was calculated according to the following ₂ Is not limited by the removal rate eta SO ₂ ：

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Wherein N is ₀ And N ₁ Respectively represent SO at the inlet and outlet ₂ Is a volume concentration of (c).

The sulfur capacity was calculated according to the following formula:

wherein M is _{Sulfur (S)} Represents the weight of the activated carbon to adsorb sulfur, M _{Catalytic action} Represents the weight of the adsorbent for adsorbing sulfur; the saturated sulfur capacity refers to the maximum amount of sulfur absorbed by the desulfurizing agent per unit weight, namely, fresh adsorbent is continuously contacted with sulfur-containing gas, and when the sulfur content of the sulfur-containing gas before and after the contact with the adsorbent is equal, the percentage of the sulfur content absorbed by the adsorbent is the saturated sulfur capacity.

Penetrating sulfur capacity: under certain use conditions, the adsorbent can absorb the weight percentage of sulfur when ensuring the process purification index. In other words, when the sulfur content in the outlet process gas is larger than the process purification index, all the spent catalyst is immediately discharged, and the sulfur capacity measured by taking an average sample is called a breakthrough sulfur capacity. In the present invention, SO ₂ Penetration is considered to be achieved when the removal rate is reduced to 99%, i.e. the penetrating sulfur capacity in the present invention refers to SO ₂ The total time that the adsorbent was used when the sulfur capacity was penetrated was defined as the adsorption duration when the removal rate was reduced to 99%.

The analysis results are shown in Table 4.

TABLE 4 Table 4

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From the results in Table 4, it can be seen that the composite material of the present invention has a higher penetrating sulfur capacity.

Test example 2

SO removal was performed on the adsorbents prepared in example 1 and comparative example 1 ₂ Test (specific method same as test example 1), when the adsorbent is used for SO ₂ Penetration of the adsorption of (C) occurs, and when the penetration of sulfur capacity of the adsorbent is reached, stopping the adsorption of SO-containing gas ₂ And (3) gas adsorption, namely converting nitrogen to inspect the regeneration performance of the adsorbent. The regeneration conditions are as follows: airspeed of 1200h ^-1 The temperature was 200 ℃, the purge gas was nitrogen, and the regeneration time was 6 hours. SO removal with regenerated adsorbent ₂ The test shows that the adsorbent is regenerated when penetrating the sulfur capacity, and the adsorbent SO after each regeneration is continuously regenerated for 5 times ₂ The breakthrough sulfur capacity results are shown in table 5.

TABLE 5

From the data in Table 5, it can be seen that the breakthrough sulfur capacity of the inventive sorbents remains substantially unchanged and that the inventive composites exhibit good regeneration performance. Further experiments demonstrated that the regeneration performance of the adsorbents obtained in examples 2-7 was similar to example 1 (results not shown).

Test example 3

Desulfurization is performed using the system of the present invention, as shown in fig. 1, which includes:

the oxidation unit is used for treating sulfur-containing gas and recovering sulfur and comprises a liquid sulfur pool 17 and a thermal reaction furnace 11, a first-stage condenser 12, a first-stage catalytic converter 13, a second-stage condenser 14, a second-stage catalytic converter 15 and a third-stage condenser 16 which are sequentially connected, wherein the liquid sulfur pool 17 is respectively connected with the first-stage condenser 12, the second-stage condenser 14 and the third-stage condenser 16 and is used for collecting cooled liquid sulfur;

the hydrogenation purification unit is connected with the oxidation unit and is used for carrying out hydrogenation reduction on the oxidation tail gas discharged by the oxidation unit and recovering hydrogen sulfide in a reduction product obtained by hydrogenation reduction, and comprises a hydrogenation reactor 21, a hydrogenation tail gas cooler 22, a quenching tower 23 and an absorption tower 24 which are connected in sequence;

an incineration unit 31 for incinerating the purified exhaust gas discharged from the hydrogenation purification unit;

An adsorption unit for adsorbing SO-containing gas obtained by incineration ₂ SO in flue gas of (C) ₂ The adsorbent used in the adsorption unit is a composite material prepared by the invention, and comprises a first adsorption tower 41 and a second adsorption tower 42, wherein the two adsorption towers can be alternately used to realize continuous adsorption;

the heat exchange unit comprises a tail gas reheater 111 and a flue gas heat exchanger 222, wherein the tail gas reheater 111 is arranged between the oxidation unit and the hydrogenation purification unit and is used for heating the oxidized tail gas discharged by the oxidation unit; the flue gas heat exchanger 222 is disposed between the incineration unit and the adsorption unit, and is used for reducing the temperature of flue gas generated by incineration.

The desulfurization procedure was as follows (specific operating conditions are shown in table 6):

(a) Treating sulfur-containing gas in an oxidation unit and recovering sulfur

The thermal reaction unit is acid gas (CO) containing 85 volume percent hydrogen sulfide ₂ Is 10% by volume, hydrocarbon is 2% by volume, NH ₃ Is 3% by volume) is partially combusted in the thermal reaction furnace 11 to sulfur dioxide: at high temperature, the hydrogen sulfide and sulfur dioxide undergo a Claus reaction to generate elemental sulfur and process gas, and the elemental sulfur enters a liquid sulfur tank 17 after being cooled by a primary condenser 12 to obtain liquid sulfur;

the process gas sequentially enters a primary catalytic converter 13, a secondary condenser 14, a secondary catalytic converter 15 and a tertiary condenser 16 of the catalytic reaction unit. After Claus catalytic conversion, elemental sulfur enters a liquid sulfur tank 17 through a secondary condenser 14 and a tertiary condenser 16; and (5) the reacted Claus tail gas enters a tail gas purifying unit.

(b) Hydrogenation reduction is carried out on the oxidized tail gas in a hydrogenation purification unit, and hydrogen sulfide in a reduction product obtained by hydrogenation reduction is recovered

The Claus tail gas is heated to 236 ℃ by a tail gas reheater 111 and then enters a hydrogenation reactor 21, sulfur-containing compounds are hydrogenated and converted into hydrogen sulfide under the action of a hydrogenation catalyst in the hydrogenation reactor 21, and then cooled by a hydrogenation tail gas cooler 22 and a quenching tower 23, and enters an absorption tower 24 with amine liquid to absorb the hydrogen sulfide in the hydrogenation tail gas, so that purified tail gas is obtained.

(c) Burning the tail gas after hydrogenation reduction in the burning unit

Purified tail gas is introduced into an incineration unit (incinerator) 31 for incineration to generate SO-containing gas ₂ Is introduced into the adsorption unit.

(d) Incinerating the obtained SO-containing material in an adsorption unit ₂ Is contacted with adsorbent to adsorb SO ₂

The flue gas enters the first adsorption tower 41 in an adsorption state after being subjected to heat exchange to 145 ℃ by the flue gas heat exchanger 222, and SO in the flue gas is adsorbed ₂ Then, the purified flue gas is discharged through a chimney, SO that SO in the purified flue gas is purified ₂ Emission control index of 20mg/m ³ . At the initial stage of operation, no SO is detected in the purified flue gas ₂ After 650h of operation, SO appears in the flue gas ₂ And the concentration is 1mg/m ³ After the operation is continued for 780 hours, SO in the flue gas ₂ Up to 8mg/m ³ After the operation is continued for 900 hours, SO in the flue gas ₂ Up to 20mg/m ³ The first adsorption tower 41 is cut off, and the second adsorption tower 42 is switched to adsorb the incineration exhaust. Simultaneously, the first adsorption tower 41 is charged with regenerated hot nitrogen for thermal regeneration, and SO-containing is generated by regeneration ₂ The regenerated gas is introduced into the primary catalytic converter 13 for reprocessing. The regeneration time was 100h (relative to 20m ³ Is contained in the adsorbent). SO in the purified flue gas to be discharged from the second adsorption tower 42 ₂ Up to 20mg/m ³ At this time, the regenerated first adsorption tower 41 is switched to perform adsorption. Finally by controlling 20mg/m ³ Adsorption precision, can realize the flue gas SO of the sulfur recovery device ₂ The discharge concentration is lower than 20mg/m ³ Meets the flue gas SO specified by the most strict environmental protection regulations at present ₂ Down to 50mg/m ³ The following requirements. Moreover, the regeneration mode is simple, and the whole treatment process is continuously clean.

Test example 4

The acid gas was desulfurized in accordance with the system and method of test example 3, except that the incinerator of the incineration unit was replaced with a catalytic incineration reactor, the regeneration mode was water-washing regeneration, as shown in fig. 2, the water-washing regeneration mode was: the first adsorption tower 41 is charged with water washing water to regenerate the adsorbent, regenerated dilute acid is produced by regeneration, and the regenerated dilute acid is introduced into the thermal reaction furnace 11 to be reprocessed. The regeneration time was 140h. The specific operating conditions for each step are shown in table 6.

TABLE 6

Test example 5

The sour gas was sweetened according to the system and method of test example 3, except that the temperature of the adsorption unit was 80℃and the gas volume space velocity was 1000h ^-1 . SO in flue gas when running for 720h ₂ Up to 20mg/m ³ 。

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.

Claims

1. A composite material is characterized by comprising modified activated carbon and an active component loaded on the modified activated carbon, wherein the modified activated carbon comprises the activated carbon, an oxide of alkali metal and an oxide of silicon, and the weight ratio of the activated carbon, the oxide of alkali metal and the oxide of silicon is 100 (0.5-2): 1-2.8; the active component contains iron oxide and rare earth element oxide, and the weight ratio of the active carbon to the iron oxide to the rare earth element oxide is 100 (1-2.2): 2-5;

The oxide of the rare earth element is CeO ₂ And La (La) ₂ O ₃ And CeO ₂ With La ₂ O ₃ The weight ratio of (2) is 1-3.

2. The composite material of claim 1, wherein the oxide of an alkali metal is K ₂ O and/or Na ₂ The oxide of O and silicon is SiO ₂ The oxide of iron is Fe ₂ O ₃ ；

And/or the specific surface area of the modified activated carbon is more than or equal to 600m ² /g; the pore volume is more than or equal to 0.4ml/g;

and/or the specific surface area of the composite material is more than or equal to 550m ² /g; the pore volume is more than or equal to 0.35ml/g; saturated sulfur capacity is more than or equal to 18%; the penetrating sulfur capacity is more than or equal to 12 percent.

3. The composite material according to claim 1, wherein the modified activated carbon has a specific surface area of 650-750m ² /g；

And/or the pore volume of the modified activated carbon is 0.4-0.45ml/g;

and/or the specific surface area of the composite material is 560-590m ² /g；

And/or the pore volume of the composite material is 0.36-0.4ml/g;

and/or the saturated sulfur capacity of the composite material is 20-25%;

and/or the composite material has a sulfur penetration capacity of 15.5-16%.

4. A method of making a composite material, the method comprising:

(1) Kneading, molding, drying and roasting the activated carbon, the alkali metal precursor, the silicon-containing binder and the optional pore-enlarging agent in the presence of a solvent to obtain modified activated carbon, wherein the weight ratio of the activated carbon, the alkali metal precursor and the silicon-containing binder in the obtained modified activated carbon is 100 (0.5-2) to 1-2.8;

(2) Contacting a precursor of an active component with the modified active carbon to load the modified active carbon with the active component, wherein the precursor of the active component contains an iron precursor and a rare earth element precursor, and the precursor of the active component is used in an amount such that the weight ratio of the active carbon to the iron element to the rare earth element in the obtained composite material is 100 (1-2.2): 2-5;

wherein the weight of the alkali metal element, the silicon element, the iron element and the rare earth element is calculated by oxide;

the precursor of the rare earth element contains a cerium precursor and a lanthanum precursor, and the weight ratio of the cerium precursor to the lanthanum precursor in the obtained composite material is 1-3.

5. The method according to claim 4, wherein the specific surface area of the activated carbon is not less than 700m ² /g；

And/or the alkali metal precursor is at least one of alkali metal bicarbonate, alkali metal carbonate, alkali metal nitrate and alkali metal sulfate;

and/or the silicon-containing binder is silica and/or silicate;

and/or the weight ratio of the active carbon to the pore-expanding agent is 100 (1-10);

and/or, the precursor of iron is a soluble ferric salt;

And/or the precursor of the rare earth element is soluble rare earth metal salt.

6. The method according to claim 5, wherein the activated carbon has a specific surface area of 700-1000m ² /g；

And/or the precursor of the alkali metal is at least one of sodium bicarbonate, potassium bicarbonate and potassium carbonate;

and/or the silicon-containing binder is silica sol and/or water glass;

and/or the pore-expanding agent is a substance capable of decomposing at a temperature of not more than 450 ℃;

and/or, the precursor of the iron is ferric nitrate and/or ferric chloride;

and/or the precursor of the rare earth element is nitrate of rare earth metal and/or chloride of rare earth metal.

7. The method of claim 6, wherein the pore-expanding agent is at least one of sesbania powder, polyethylene glycol, starch, and citric acid.

8. The method according to claim 4 or 5, wherein in step (1):

the drying mode is as follows: drying at 40-80deg.C for 2-4 hr; drying at 100-160deg.C for 4-6 hr;

and/or, the roasting conditions include: roasting at 400-700 deg.c for 3-8 hr;

and/or, in step (2):

the mode for loading the active components on the modified activated carbon is as follows: the modified activated carbon is subjected to isovolumetric impregnation with a solution of a precursor containing the active component, the impregnate is dried, and the dried product is calcined.

9. The method of claim 8, wherein in step (1): the drying mode is as follows: drying at 40-80deg.C for 2-4 hr; drying at 110-130deg.C for 4-6 hr;

and/or, in step (1): the roasting conditions include: the roasting temperature is 450-600 ℃ and the roasting time is 4-6h;

and/or, in step (2): the conditions for isovolumetric infusion included: the temperature is 5-40 ℃; the time is 20min-3h;

and/or, in step (2): the conditions for drying the impregnate included: the temperature is 80-160 ℃; the time is 2-10h;

and/or, in step (2): the conditions under which the dried product is calcined include: the roasting temperature is 300-500 ℃ and the roasting time is 2-10h.

10. The method according to claim 8 or 9, wherein in step (2): the conditions for isovolumetric infusion included: the temperature is 20-30 ℃; the time is 0.5-1h;

and/or, in step (2): the conditions for drying the impregnate included: the temperature is 110-130 ℃; the time is 4-6h;

and/or, in step (2): the conditions under which the dried product is calcined include: the roasting temperature is 350-450 ℃ and the roasting time is 3-5h.

11. A composite material obtainable by the process of any one of claims 4 to 10.

12. Use of the composite material of claim 1, 2 or 11 for adsorptive desulfurization.

13. A method of desulfurizing, the method comprising: contacting the sulfur-containing gas to be treated with the composite material of claim 1, 2 or 11;

alternatively, the method comprises: preparing a composite material according to the method of any one of claims 4-10; and then contacting the sulfur-containing gas with the obtained composite material.

14. The process according to claim 13, wherein the sulfur dioxide content of the sulfur-containing gas is not higher than 6000mg/m ³ ；

And/or, the contacting conditions include: the temperature is 100-150 ℃, and the gas volume space velocity is 1500-2000h ^-1 ；

And/or, the method further comprises: regenerating the composite material;

and/or the sulfur-containing gas is at least one of petroleum refining industrial heating furnace flue gas, sulfur tail gas and catalytic cracking regeneration flue gas.

15. The process according to claim 14, wherein when the sulfur dioxide content in the sulfur-containing gas is higher than 6000mg/m ³ When the method further comprises reducing the sulfur dioxide content of the sulfur-containing gas to 6000mg/m before contacting the composite material ³ The following are set forth;

and/or the regeneration mode is thermal regeneration and/or water washing regeneration.

16. The method of claim 15, wherein the thermal regeneration is by a gas purge, the conditions of the gas purge comprising: the gas volume space velocity is 1000-1500h ^-1 The temperature is 150-250 ℃, and the purging gas is nitrogen;

and/or, the conditions of the water washing regeneration comprise: the liquid hourly space velocity is 0.5 to 1.5h ^-1 The temperature is 25-40 ℃.

17. An apparatus having a desulfurization function, comprising:

an oxidation unit for treating sulfur-containing gas and recovering sulfur;

an adsorption unit for adsorbing SO-containing gas obtained by incineration ₂ SO in flue gas of (C) ₂ The adsorbent used in the adsorption unit is the composite material according to any one of claims 1, 2 or 11.

18. A method of desulfurizing, the method comprising:

(a) Oxidizing sulfur-containing gas to be treated and recovering sulfur;

(c) Burning the tail gas after hydrogenation reduction;

(d) SO-containing obtained by incineration ₂ Is contacted with adsorbent to adsorb SO ₂ The adsorbent is the composite material of claim 1, 2 or 11.

19. The method of claim 18, wherein the method is implemented in the apparatus of claim 17.