CN108342217A - One kind is with Ag2O/SiO2Graphene oxide composite aerogel is the method that adsorbent removes thiophene sulphur in fuel oil - Google Patents

Abstract

The invention discloses a method for removing thiophene sulfur in fuel oil by using Ag ₂ O/SiO ₂ -graphene oxide composite airgel as an adsorbent, belonging to the technical field of fuel oil processing. The method uses methyl orthosilicate, ethyl orthosilicate, silica _sol , water glass, etc. SiO ₂ ‑graphene oxide composite airgel. Fill it quantitatively in a fixed bed adsorption device, inject simulated gasoline containing thiophene sulfur at a certain temperature and space velocity, collect the adsorbed simulated gasoline at the outlet of the lower end of the reaction device, and perform chromatographic analysis. The results show that Ag ₂ O/SiO ₂ ‑graphene oxide composite aerogels have good adsorption properties for thiophene sulfur. The preparation method of the Ag ₂ O/SiO ₂ -graphene oxide composite airgel adsorbent in the present invention is simple and low in cost. Equipment requirements are low.

Description

A kind of Ag2O/SiO2-graphene oxide composite airgel as adsorbent for fuel removal Method for Thiophene Sulfur in Oil

technical field

The invention belongs to the technical field of fuel oil processing, and in particular relates to an Ag ₂ O/SiO ₂ -graphene oxide composite airgel desulfurization adsorbent with π complex adsorption, a preparation method thereof, and an application in gasoline desulfurization.

Background technique

With the vigorous development of the automobile industry, the large amount of sulfide emissions from automobile exhaust not only makes environmental pollution more and more serious, but also threatens human health. Fuel cells also have very high requirements on the sulfur content in fuel oil. The presence of organic sulfides will poison the catalyst in the fuel cell electrodes, making the fuel cells unable to effectively convert the chemical energy in diesel gasoline into electrical energy. Therefore, the deep desulfurization of fuel oil has become the focus of global attention.

At present, the desulfurization technology of fuel oil mainly includes hydrodesulfurization technology, alkylation desulfurization technology, biological desulfurization technology, extraction desulfurization technology, oxidation desulfurization technology, adsorption desulfurization technology, etc. In current industrial production, the main process of desulfurization is still traditional hydrodesulfurization, but its operating cost is high, hydrogen consumption is large, operating conditions are harsh, and the octane number in gasoline is reduced. Moreover, hydrodesulfurization only has a good effect on mercaptans, sulfides, inorganic sulfur, etc., and has a poor desulfurization effect on thiophene sulfides with high thermal stability. Adsorption desulfurization is due to its low cost, mild operating conditions, good desulfurization effect, and no environmental pollution. Compared with physical adsorption desulfurization, π complex adsorption desulfurization is selective, and it is easier to desorb and regenerate chemical adsorption desulfurization. Prospects for desulfurization methods.

The key to π-complex adsorption desulfurization lies in the preparation of an efficient π-complex adsorbent. Metal ions commonly used to prepare π-complex desulfurization adsorbents include Cu ²⁺ , Ag ⁺ , Ni ²⁺ , Co ²⁺ , etc. To prepare π-complex desulfurization adsorbents, these metal ions must be dispersed on a carrier with a high specific surface area. According to different carriers, π-complex desulfurization adsorbents can be divided into molecular sieves, activated carbons, and metal oxides.

π-complex desulfurization adsorbent with molecular sieve as carrier. Shenyang University of Chemical Technology (publication number CN 103170305 A) uses 13X molecular sieve loaded with Ag ions as a desulfurization adsorbent for deep removal of thiophene and its derivatives and benzothiophene in gasoline. The silver element content accounts for 3% to 5% of the total weight of the adsorbent, and the silver element is in an ion state. The Chinese Academy of Sciences (publication number CN 1511629 A) prepared a molecular sieve adsorbent for deep removal of sulfide, which is composed of Y-type molecular sieve loaded with metal salts. This type of π-complex adsorbent has a low-cost carrier, a simple preparation method, and can be recycled. However, the number of transition metal ions exchanged by the microporous molecular sieve desulfurization adsorbent is limited, the adsorption capacity for sulfide is not large, and the microporous structure of the microporous molecular sieve itself, the macromolecular thiophene sulfide cannot enter the channel due to the molecular size effect Form π complexation with metal ions, that is, deep desulfurization cannot be achieved.

π-complex desulfurization adsorbent with activated carbon as the carrier. Shenyang University of Chemical Technology (public number CN 103143322 A) prepared an activated carbon adsorbent loaded with Fe ions, which has a large adsorption capacity and selectivity for thiophene and its derivatives in gasoline, and the preparation method is simple and easy to regenerate. The adsorbent has a long service life. China Petrochemical Co., Ltd. (publication number CN 104549143 A) modified activated carbon by using salts containing Al, Zn, Ni and other metals and H ₃ PO ₄ as auxiliary agents, and solved the problem of adsorption, purification and desulfurization of gas raw materials. There are problems in the technology that a single adsorbent cannot effectively remove multiple sulfides at the same time, the sulfur removal rate is low, and the breakthrough sulfur capacity of the desulfurizer is low. However, the pore structure of activated carbon is dominated by micropores, and the adsorption capacity of modified activated carbon for thiophene macromolecular sulfides is still very small, which is difficult to meet the requirements of industrial production.

π-complex desulfurization adsorbent with metal oxide as carrier. Nantong University (Publication No. CN 10300787 A) contacted copper-doped mesoporous γ-Al ₂ O ₃ with sulfur-containing fuel oil to achieve desulfurization by adsorption method. The operation cost is low, the adsorption capacity is large, and regeneration is convenient. China Petrochemical Co., Ltd. (public number CN 10161923 A) has prepared a desulfurization adsorbent, which includes alumina as a binder and zinc oxide as a carrier, then contacts with a complexing agent solution, and then loads metals to promote agent. It is used for desulfurization of fuel oil, with high activity and large adsorption capacity of sulfur. However, during the preparation process, metal ions are easy to block the pores of metal oxides, resulting in the accumulation of loaded active components on the surface, which cannot enter the pores to provide active sites, reducing the adsorption and desulfurization performance, and this method is difficult to apply to industrial production.

Contents of the invention

In view of the above-mentioned problems existing in the existing π complex adsorbents in the removal of thiophene sulfur in fuel oil, the purpose of the present invention is to provide a Ag ₂ O/SiO ₂ -graphene oxide composite gas with large adsorption capacity and easy regeneration. The gel is an adsorbent, the adsorption condition is mild, and the method for removing thiophene sulfur in fuel oil through π complex adsorption.

The method for removing thiophene sulfur in fuel oil using Ag ₂ O/SiO ₂ -graphene oxide composite airgel as an adsorbent is characterized in that the Ag ₂ O/SiO ₂ -graphene oxide composite gas The gel is used as the adsorbent, and the adsorbent is filled into a fixed-bed adsorption device. At a temperature of 0-100°C, a simulated gasoline containing thiophene sulfur is passed through at a space velocity of 1-10h ^-1 , and 10ppm is obtained after adsorption. Simulated gasoline with the following sulfur concentrations.

The method for removing thiophene-like sulfur in fuel oil using Ag ₂ O/SiO ₂ -graphene oxide composite airgel as an adsorbent is characterized in that the thiophene-like sulfur is thiophene or benzothiophene.

The method for removing thiophene sulfur in fuel oil using Ag ₂ O/SiO ₂ -graphene oxide composite airgel as an adsorbent is characterized in that Ag ₂ O/SiO ₂ -graphene oxide composite airgel The gel adsorbent is prepared by the sol-gel-normal pressure drying method.

The method for removing thiophene sulfur in fuel oil using Ag ₂ O/SiO ₂ -graphene oxide composite airgel as an adsorbent is characterized in that the preparation of Ag ₂ O/SiO ₂ -graphene oxide composite gas The silicon source of the gel adsorbent is methyl orthosilicate, orthosilicate ethyl ester, silica sol or water glass; the silver source is silver nitrate or silver acetate, preferably the silicon source is tetraethyl orthosilicate, and the silver source is silver nitrate .

The method for removing thiophene sulfur in fuel oil using Ag ₂ O/SiO ₂ -graphene oxide composite airgel as an adsorbent is characterized in that Ag ₂ O/SiO ₂ -graphene oxide composite airgel The silicon-silver molar ratio in the gel adsorbent is 1:1-20:1, preferably 2:1-10:1.

The method for removing thiophene sulfur in fuel oil using Ag ₂ O/SiO ₂ -graphene oxide composite airgel as an adsorbent is characterized in that Ag ₂ O/SiO ₂ -graphene oxide composite airgel 0.1-10 mg of graphene oxide, preferably 4 mg-6 mg, is added to the gel adsorbent during the preparation process.

The method for removing thiophene-like sulfur in fuel oil using Ag ₂ O/SiO ₂ -graphene oxide composite airgel as an adsorbent is characterized in that the hourly space velocity of simulated gasoline containing thiophene-like sulfur is 1 ~5h ^-1 .

The method for removing thiophene sulfur in fuel oil using Ag ₂ O/SiO ₂ -graphene oxide composite airgel as an adsorbent is characterized in that Ag ₂ O/SiO ₂ -graphene oxide composite airgel The adsorption temperature of the glue to adsorb thiophene sulfur is 0-40°C.

The method for removing thiophene sulfur in fuel oil using Ag ₂ O/SiO ₂ -graphene oxide composite airgel as an adsorbent is characterized in that the concentration of thiophene or benzothiophene sulfur in simulated gasoline is 0.1- 10mgS/g, preferably 0.1-5mgS/g.

By adopting above-mentioned technology, compared with prior art, the beneficial effect of the present invention is as follows:

1) The Ag ₂ O/SiO ₂ -graphene oxide composite airgel of the present invention has typical mesoporous characteristics, the pore diameter

(5-20nm), high porosity (85-99%), high specific surface area (600-1500m ² /g) and other unique physical and chemical properties. Therefore, thiophene sulfides can enter the airgel pores without hindrance, and the active components can fully contact with the sulfides;

2) The Ag ₂ O/SiO ₂ -graphene oxide composite airgel of the present invention is used as a π-complex desulfurization adsorbent, compared with other π-complex adsorbents, its structure is composed of nano-scale framework particles, so that the The active ingredients are fully exposed. During the synthesis of airgel, transition metal salts with π complexation can be added to it, so the amount of active components can be adjusted;

3) The Ag ₂ O/SiO ₂ -graphene oxide composite airgel of the present invention, compared with Ag ₂ O/SiO ₂ aerogel, introduces graphene oxide into the airgel silicon skeleton structure, which not only enhances The strength of the airgel skeleton is improved, and the surface of the introduced oxidized graphene oxide has rich functional groups, which is also conducive to further improving its adsorption performance for thiophene sulfur;

4) In the Ag ₂ O/SiO ₂ -graphene oxide composite airgel of the present invention, the skeleton structure is further strengthened after graphene is incorporated, and the high temperature resistance is further improved, thereby improving the adsorption performance;

5) The Ag ₂ O/SiO ₂ -graphene oxide composite airgel π complex adsorbent of the present invention has good adsorption performance for thiophene sulfides, can be regenerated by solvent washing, and still has good adsorption performance after regeneration ;

6) The adsorption reaction of the present invention is carried out under normal pressure, the adsorption conditions are mild, the requirements for adsorption equipment are low, the operation is convenient, and the adsorption effect on thiophene compounds is good.

Detailed ways

The present invention will be further described below in conjunction with specific examples, but the protection scope of the present invention is not limited thereto.

Example: Preparation of Ag ₂ O/SiO ₂ -Graphene Oxide Composite Airgel Adsorbent

Taking the Ag ₂ O/SiO ₂ -graphene oxide composite airgel adsorbent with a silicon-silver molar ratio of 5 as an example, its preparation method is as follows:

First prepare 3 beakers A, B and C. Add 15mL EtOH and 8mL TEOS to beaker A and mix in turn, adjust the pH to about 1.5 with nitric acid solution, and mix evenly under magnetic stirring conditions; weigh 0.0045g graphene oxide and add it to beaker B containing 2mL H ₂ O to dissolve, and Ultrasound for about 30 minutes to form solution B; weigh 1.2g of silver nitrate and dissolve it in beaker C containing 4mLH ₂ O to form solution C; when the mixed solution in beaker A is evenly mixed, mix solution B and C The solution was added to beaker A in turn. After hydrolyzing the obtained mixed solution A for 90 minutes, add ammonia water to adjust the pH value to 6.5, and let it stand at room temperature for about 5 minutes to obtain Ag ₂ O/SiO ₂ -graphene oxide composite alcohol gel, and then in anhydrous gel with a volume ratio of 25:15 Aging in ethanol/orthosilicon acetate for 16 hours to enhance the skeleton structure of the gel, and then replace the gel with n-hexane, and replace the solvent twice within 24 hours to remove ethanol, water, acid and other organic substances in the gel. molecular. Finally, it was dried at 80° C. to 150° C. for 2 hours to obtain Ag ₂ O/SiO ₂ -graphene oxide composite airgel with a silicon-silver molar ratio of 5:1.

Examples 1-5: Adsorption performance of Ag ₂ O/SiO ₂ -graphene oxide composite aerogels with different silicon sources and silver sources on thiophene sulfides in simulated gasoline

In the Ag ₂ O/SiO ₂ -graphene oxide composite airgel prepared by the sol-gel method, the silicon sources used include methyl orthosilicate, ethyl orthosilicate, and silica sol, and the silver sources include silver nitrate , Silver acetate. The prepared Ag ₂ O/SiO ₂ -graphene oxide composite aerogel was subjected to penetration adsorption desulfurization experiment. The specific operation was as follows: In the fixed bed reactor, the bottom layer was filled with an appropriate amount of absorbent cotton, and then filled with 1g of Ag ₂ O/SiO ₂ -graphene oxide airgel with appropriate amount of quartz sand. Before the adsorption experiment started, the packed adsorbent was fully wetted with n-heptane. Feed simulated gasoline, collect the adsorbed simulated gasoline at the outlet of the lower end of the reactor, and carry out chromatographic analysis. When the sulfur concentration in the effluent is 0.005mgS/g, it is defined as the breakthrough point. The obtained breakthrough adsorption capacities of thiophene and benzothiophene are shown in Table 1 and Table 2.

Table 1 Adsorption performance of Ag ₂ O/SiO ₂ -graphene oxide composite aerogels with different silicon sources on thiophene sulfides in simulated gasoline

Table 2 Adsorption performance of Ag ₂ O/SiO ₂ -graphene oxide composite aerogels with different silver sources on thiophene sulfides in simulated gasoline

It can be seen from Table 1 and Table 2 that when the silicon source and silver source used in the synthesis of Ag ₂ O/SiO ₂ -graphene oxide composite aerogels are tetraethyl orthosilicate and the silver source is silver nitrate , the synthesized Ag ₂ O/SiO ₂ -graphene oxide composite airgel has the largest breakthrough adsorption capacity for thiophene and benzothiophene in the penetration adsorption experiment. Therefore, it is preferred that the silicon source is tetraethyl orthosilicate, and the silver source is silver nitrate.

Examples 6-9: Adsorption performance of Ag ₂ O/SiO ₂ -graphene oxide composite aerogels with different silicon-silver molar ratios on thiophene sulfides in simulated gasoline

Ag ₂ O/SiO ₂ -graphene oxide aerogels with silicon-silver molar ratios of 1, 3, 5, and 10 were selected to conduct penetration adsorption experiments on thiophene sulfides in simulated gasoline. The operation of the breakthrough adsorption experiment is the same as in Examples 1-5, and the adsorption results are shown in Table 3.

Table 3 Adsorption performance of Ag ₂ O/SiO ₂ -graphene oxide composite aerogels with different molar ratios of silicon to silver on thiophene sulfides in simulated gasoline

It can be seen from Table 3 that the breakthrough adsorption capacity of Ag ₂ O/SiO ₂ -graphene oxide aerogels for thiophene and benzothiophene increases first and then decreases with the decrease of the silicon-silver molar ratio, that is, the increase of silver content. . When the silicon-silver molar ratio is 5:1, the breakthrough adsorption capacity of thiophene and benzothiophene reaches the maximum, so Ag ₂ O/SiO ₂ -graphene oxide gas with a silicon-silver molar ratio of 3:1-10:1 is preferred. gel.

Implementation cases 10-15: Adsorption performance of Ag ₂ O/SiO ₂ -graphene oxide composite aerogels with different contents of graphene oxide on thiophene sulfides in simulated gasoline

Ag ₂ O/SiO ₂ -graphene oxide aerogels mixed with 0.5 mg, 1.5 mg, 3.5 mg, 4.5 mg, 6.5 mg, and 8.5 mg of graphene oxide were used to penetrate thiophene sulfides in simulated gasoline. Permeation adsorption experiment. The operation of the breakthrough adsorption experiment is the same as in Examples 1-5, and the adsorption results are shown in Table 4.

Table 4 Adsorption performance of Ag ₂ O/SiO ₂ -graphene oxide composite aerogels mixed with different contents of graphene oxide on thiophene sulfides in simulated gasoline

It can be seen from Table 4 that the breakthrough adsorption capacity of Ag ₂ O/SiO ₂ -graphene oxide airgel for thiophene and benzothiophene increases first and then decreases with the increase of graphene oxide doping amount. When the doping amount of graphene oxide reaches 4.5mg, the breakthrough adsorption capacity of thiophene and benzothiophene reaches the maximum, so Ag ₂ O/SiO ₂ -graphene oxide with a doping amount of graphene oxide of 3.5mg-6.5mg is preferred airgel.

Implementation Cases 16-20: Adsorption performance of Ag ₂ O/SiO ₂ -graphene oxide composite aerogels for thiophene sulfides in simulated gasoline with different space velocities

The Ag ₂ O/SiO ₂ -graphene oxide composite airgel with a silicon-silver molar ratio of 5:1 is selected. The breakthrough adsorption experiments were carried out on thiophene sulfides in simulated gasoline at the space velocity of 1h ^-1 , 2h ^-1 , 4h ^-1 , 6h ^-1 and 8h ^-1 . The operation of the breakthrough adsorption experiment is the same as in Examples 1-5, and the adsorption results are shown in Table 7.

Table 5 Adsorption performance of Ag ₂ O/SiO ₂ -graphene oxide composite aerogels on thiophene sulfides in simulated gasoline at different space velocities

It can be seen from Table 5 that the breakthrough adsorption capacity of thiophene and benzothiophene will gradually increase with the ^decrease of space velocity. Therefore, the space velocity is preferably 1 to 5 h ^-1 .

Implementation Cases 21-25: Adsorption performance of Ag ₂ O/SiO ₂ -graphene oxide composite aerogels for thiophene sulfides in simulated gasoline at different adsorption temperatures

The Ag ₂ O/SiO ₂ -graphene oxide composite airgel with a silicon-silver molar ratio of 5:1 is selected. The adsorption temperature was selected as 0°C, 25°C, 40°C, 80°C, and 100°C, respectively, and the penetration adsorption experiments were carried out on thiophene sulfides in simulated gasoline. The operation of the breakthrough adsorption experiment was the same as in Examples 1-6, and the adsorption results are shown in Table 6.

Table 6 Adsorption performance of Ag ₂ O/SiO ₂ -graphene oxide composite aerogels on thiophene sulfides in simulated gasoline at different adsorption temperatures

It can be seen from Table 6 that as the adsorption temperature increases, the breakthrough adsorption capacity of thiophene and benzothiophene gradually decreases. After 80 °C, the adsorption breakthrough capacity of thiophene and benzothiophene is very small, indicating that in this At high temperature, the thiophene and benzothiophene adsorbed by the Ag ₂ O/SiO ₂ -graphene oxide composite airgel have been desorbed. Therefore, the preferred adsorption temperature is 0-40°C.

Implementation Cases 26-31: Effects of Different Sulfur Concentrations on Ag ₂ O/SiO ₂ -Graphene Oxide Composite Airgel Adsorption Performance of Thiophene Sulfides in Simulated Gasoline

The Ag ₂ O/SiO ₂ -graphene oxide composite airgel with a silicon-silver molar ratio of 5:1 is selected. The sulfur concentrations of thiophene or benzothiophene in simulated gasoline were respectively 0.1mgS/g, 0.5mgS/g, 1mgS/g, 2mgS/g, 5mgS/g, and 10mgS/g for breakthrough adsorption experiments. The breakthrough adsorption operation is the same as in Examples 1-5, and the adsorption results are shown in Table 7.

Table 7 Adsorption performance of Ag ₂ O/SiO ₂ -graphene oxide composite aerogels for thiophene sulfides in simulated gasoline with different sulfur concentrations

It can be seen from Table 7 that the breakthrough adsorption capacity of Ag ₂ O/SiO ₂ -graphene oxide composite aerogels for thiophene and benzothiophene decreased with the increase of thiophene or benzothiophene sulfur concentration in simulated gasoline. Therefore, it is preferable that the sulfur concentration of thiophene or benzothiophene in simulated gasoline is 0.1-5 mgS/g.

Claims (9)

1. A method using Ag ₂ O/SiO ₂ -graphene oxide composite airgel as an adsorbent to remove thiophene sulfur in fuel oil, characterized in that the Ag ₂ O/SiO ₂ -graphene oxide composite airgel Glue is used as the adsorbent, and the adsorbent is filled into a fixed-bed adsorption device, and the simulated gasoline containing thiophene sulfur is passed through at a temperature of 0-100 °C at a space velocity of 1-10 h ^-1 , and 10 ppm of sulfur is obtained after adsorption. Simulated gasoline with the following sulfur concentrations. 2. A method for removing thiophene-like sulfur in fuel oil using _Ag2O / _SiO2 -graphene oxide composite airgel as an adsorbent according to claim 1, wherein the thiophene-like sulfur is thiophene or benzene And thiophene. 3. A method for removing thiophene sulfur in fuel oil using Ag ₂ O/SiO ₂ -graphene oxide composite airgel as an adsorbent according to claim 1, characterized in that Ag ₂ O/SiO ₂ - The graphene oxide composite airgel adsorbent is prepared by a sol-gel-normal pressure drying method. 4. A method for removing thiophene sulfur in fuel oil using Ag ₂ O/SiO ₂ -graphene oxide composite airgel as an adsorbent according to claim 1, characterized in that Ag ₂ O/SiO ₂ is prepared -The silicon source of the graphene oxide composite airgel adsorbent is methyl orthosilicate, orthoethyl silicate, silica sol or water glass; the silver source is silver nitrate or silver acetate, preferably the silicon source is ethyl orthosilicate , the silver source is silver nitrate. 5. A method for removing thiophene sulfur in fuel oil using Ag ₂ O/SiO ₂ -graphene oxide composite airgel as an adsorbent according to claim 1, characterized in that Ag ₂ O/SiO ₂ - The silicon-silver molar ratio in the graphene oxide composite airgel adsorbent is 1:1-20:1, preferably 2:1-10:1. 6. A method for removing thiophene sulfur in fuel oil using Ag ₂ O/SiO ₂ -graphene oxide composite airgel as an adsorbent according to claim 1, characterized in that Ag ₂ O/SiO ₂ - The graphene oxide composite airgel adsorbent is mixed with 0.1-10 mg of graphene oxide, preferably 4 mg-6 mg, during the preparation process. 7. A method for removing thiophene-like sulfur in fuel oil using Ag ₂ O/SiO ₂ -graphene oxide composite airgel as an adsorbent according to claim 1, characterized in that the gas containing thiophene-like sulfur is passed through The simulated gasoline hourly space velocity is 1~5 h ^-1 . 8. A method for removing thiophene sulfur in fuel oil using Ag ₂ O/SiO ₂ -graphene oxide composite airgel as an adsorbent according to claim 1, characterized in that Ag ₂ O/SiO ₂ - The adsorption temperature of graphene oxide composite airgel for adsorption of thiophene sulfur is 0-40 ℃. 9. A method of using Ag ₂ O/SiO ₂ -graphene oxide composite airgel as an adsorbent to remove thiophene sulfur in fuel oil according to claim 2, characterized in that thiophene or benzo in simulated gasoline The concentration of thiophene sulfur is 0.1-10 mgS/g, preferably 0.1-5 mgS/g.