Method for removing sulfur-containing compounds in C3 fraction of cracking gas prepared from crude oil

Abstract

The invention discloses a method for removing sulfur-containing compounds in a crude oil-prepared cracked gas C3 fraction. The method comprises the following steps: contacting the crude oil-prepared cracked gas C3 fraction with a supported desulfurizer, wherein the load type desulfurizing agent comprises a carrier and a main active component loaded on the carrier; the main active component comprises alkali metal and / or alkaline earth metal; the carrier comprises elementary substances Ag, Ag2O, elementary substances Re and ReOx; reOx is a mixture of a plurality of Re oxides, x = n / 2, and n is 4, 6 or 7; the molar content of the elementary substance Re accounts for 30-45% of the total molar weight of Re in the carrier. The method provided by the invention can effectively remove low-carbon thioether and / or low-carbon mercaptan in the C3 fraction of the crude oil-prepared pyrolysis gas, has the advantages of low removal temperature, simple process, no additional reaction, no influence on downstream hydrogenation and separation processes, and energy consumption saving, and the desulfurizer can be repeatedly regenerated and used, and has long-period stable operation capability.

Description

Technical Field

[0001] This invention relates to the field of desulfurization technology, specifically to a method for removing sulfur-containing compounds from the C3 fraction of crude oil cracked gas. Background Technology

[0002] In crude oil refining, many impurities in crude oil are removed and refined at the downstream end of the refining process, targeting products with different distillation ranges. Because crude oil steam cracking technology struggles to remove and refine impurities upstream of the steam cracking process, impurity removal must be carried out specifically in the separation process. Unlike conventional cracking processes, crude oil cracked gas typically contains hydrogen sulfide and organic sulfides. While most of the hydrogen sulfide can be removed in an alkaline scrubbing tower, organic sulfides cannot be removed in existing separation processes. This is highly detrimental to downstream separation and product quality, necessitating the establishment of an organic sulfide refining and removal unit.

[0003] Sulfur is a common impurity in chemical processes, directly affecting product quality and corroding equipment. In some processes, sulfur is also a poison to downstream catalysts, affecting their normal operation. In most cases, sulfur impurities must be removed. Sulfur compounds can be divided into inorganic sulfur and organic sulfur. Inorganic sulfur mainly includes hydrogen sulfide and sulfur dioxide, which are relatively easy to remove industrially using solvent absorption or desulfurizing agents. Organic sulfur mainly includes thiols, thioethers, thiophene, carbonyl sulfide, and carbon disulfide, which are more difficult to remove. Currently, the commonly used industrial methods are hydrogenation and catalytic hydrolysis for desulfurization.

[0004] Hydrodesulfurization involves catalytically hydrogenating organic sulfur in the feedstock to convert it into inorganic sulfur, which is then removed. Currently, industrially used hydrodesulfurizing agents are mainly catalysts with Co, Mo, and Ni as the main active components. CN114768863A discloses a heavy oil hydrodesulfurization catalyst that reduces sulfur poisoning by adding a special molecular sieve coating to an alumina support loaded with active metal W-Mo-Ni-Co, thus preventing contact between the active metal and sulfur. The catalyst was evaluated using atmospheric residue oil with a sulfur content of 3.3% at a reaction temperature of 380℃, a hydrogen partial pressure of 14 MPa, and a liquid hourly space velocity of 0.6 h⁻¹. -1 Under these conditions, the catalyst still maintains a relative sulfur removal activity of up to 99.7% after 500 hours of reaction. However, the catalyst has a complex preparation process, requires high reaction temperatures, and incurs high investment and operating costs.

[0005] Catalytic hydrolysis desulfurization involves first hydrolyzing sulfides onto a catalyst to convert them into hydrogen sulfide, which is then adsorbed and removed. Currently, commercially available traditional organic sulfur hydrolysis desulfurizers mainly include alumina-based, titanium dioxide-based, and activated carbon-based iron oxide desulfurizers, zinc oxide desulfurizers, and nano-adsorbent materials. Organic sulfur (mainly COS) and inorganic sulfur (mainly H2S) present in blast furnace gas are primarily removed using hydrolysis desulfurizers. However, traditional desulfurizers (such as iron oxide desulfurizers, zinc oxide desulfurizers, activated carbon desulfurizers, and nano-adsorbent materials) have short service lives and high replacement costs. The waste generated after replacement also places a heavy burden on chemical companies. Furthermore, waste desulfurizers, due to their adsorption and accumulation of elemental sulfur, are hazardous wastes. Long-term exposure to the air causes air pollution, and harmful substances in waste desulfurizers can dissolve and seep into the ground and into rivers, lakes, and seas through water flushing, causing pollution of soil and water bodies and damaging the ecological environment.

[0006] The C3 fraction of cracked gas contains a large amount of unsaturated hydrocarbons, which are highly reactive and easily initiate hydrogenation, oxidation, and polymerization reactions on the surface of the desulfurizing agent. How to effectively remove hydrogen sulfide and organic sulfur without triggering excessive catalytic reactions places extremely high demands on the desulfurization process and the performance of the desulfurizing agent. Summary of the Invention

[0007] The purpose of this invention is to overcome the problem of other reactions occurring in the C3 fraction of cracked gas during the desulfurization process in existing technologies, and to provide a method for removing sulfur-containing compounds from the C3 fraction of crude oil cracked gas. This method utilizes Al2O3-Al(OH)3-Ag-Ag2O-Re-ReO x Alkali metal and / or alkaline earth metal desulfurizers remove trace amounts of sulfur compounds from the C3 fraction of crude oil cracked gas. They can efficiently remove and refine sulfur at lower temperatures without causing other reactions in the C3 fraction of cracked gas, and the desulfurizers can be repeatedly regenerated and reused.

[0008] To achieve the above objectives, the present invention provides a method for removing sulfur-containing compounds from the C3 fraction of crude oil cracked gas. The method includes: contacting the C3 fraction of crude oil cracked gas with a supported desulfurizing agent; wherein the supported desulfurizing agent includes a carrier and a main active component loaded on the carrier; the main active component includes an alkali metal and / or an alkaline earth metal; the carrier includes Al2O3, Al(OH)3, elemental Ag, Ag2O, elemental Re, and ReO. x ReO x It is a mixture of various Re oxides, wherein x = n / 2, and n has a value of 4, 6, or 7; the molar content of elemental Re accounts for 30-45% of the total molar amount of Re in the carrier.

[0009] The beneficial technical effects achieved by the present invention through the above technical solution are as follows:

[0010] (1) The method of the present invention uses an alkali metal and / or alkaline earth metal desulfurizing agent whose carrier contains Ag-Ag2O-Re-ReO. x It can remove sulfur-containing compounds from the C3 fraction of crude oil cracked gas through elemental Ag, Ag₂O, elemental Re, and ReO. x The synergistic effect effectively enhances the sulfur removal and purification capabilities of the active components, enabling the desulfurizing agent to achieve efficient desulfurization and purification at lower temperatures. At the same time, it avoids unnecessary reactions and does not affect the downstream hydrogenation and separation processes. The removal process is simple, saves energy, and the desulfurizing agent can be repeatedly regenerated and reused.

[0011] (2) The method of the present invention can effectively remove low-carbon sulfides and / or low-carbon mercaptans from the C3 fraction of crude oil cracking gas. The removal temperature is low, the process is simple, it will not trigger additional reactions, it will not affect the downstream hydrogenation and separation process, save energy, and the desulfurizing agent can be repeatedly regenerated and has the ability to operate stably for a long period of time. Attached Figure Description

[0012] Figure 1 The image shows the X-ray photoelectron spectroscopy (XPS) of Re in the carrier of the desulfurizing agent A-1 prepared in Example 1.

[0013] Figure 2 The image shows the X-ray photoelectron spectroscopy (XPS) of Ag in the carrier of the desulfurizing agent A-1 prepared in Example 1. Detailed Implementation

[0014] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0015] This invention provides a method for removing sulfur-containing compounds from the C3 fraction of crude oil cracked gas. The method includes: contacting the C3 fraction of crude oil cracked gas with a supported desulfurizing agent; wherein the supported desulfurizing agent includes a carrier and a main active component loaded on the carrier; the main active component includes an alkali metal and / or an alkaline earth metal; the carrier includes Al2O3, Al(OH)3, elemental Ag, Ag2O, elemental Re, and ReO. x ReO xThe support is a mixture of various Re oxides, where x = n / 2, and n is 4, 6, or 7. The molar content of elemental Re accounts for 30-45% of the total molar amount of Re in the support, for example, 30%, 31%, 32%, 35%, 37%, 39%, 40%, 42%, 45%, or any value within any range of two such values, preferably 32-43%. According to the present invention, the support contains Al₂O₃, Al(OH)₃, Ag, Ag₂O, Re, and ReO. x Uniformly distributed, Ag and Re are in elemental form, Ag₂O and ReO x It is in the oxidized state; through elemental Ag, Ag₂O, elemental Re and ReO x The synergistic effect enables the desulfurizing agent to have desulfurization capabilities at lower temperatures, and it can be used to remove trace amounts of sulfur-containing compounds from the C3 fraction of crude oil cracking gas, accurately achieving desulfurization to the ppb level.

[0016] According to this invention, Ag possesses a certain sulfur adsorption capacity, but its chemical form significantly affects desulfurization efficiency. Traditional impregnation processes load Ag onto a carrier surface, typically resulting in an aggregated, sheet-like distribution, which greatly reduces Ag's sulfur adsorption efficiency. Therefore, it is necessary to improve the distribution of Ag on the carrier. Research has found that Re has a good synergistic effect with Ag; Re can prevent excessive Ag aggregation and alter Ag's chemical shift, enhancing Ag's adsorption capacity for hydrogen sulfide and organic sulfur. This invention utilizes elemental Ag, Ag₂O, elemental Re, and ReO. x The synergistic effect effectively enhances the sulfur removal and purification capabilities of the active components, enabling the desulfurizing agent to achieve efficient desulfurization and purification at lower temperatures. By significantly reducing the desulfurization temperature, unnecessary reactions are avoided at room temperature or far below the hydrodesulfurization temperature.

[0017] According to some embodiments of the present invention, the molar content of elemental Ag accounts for 50-60% of the total molar amount of Ag in the carrier, for example, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, and any value within any range of any two values, preferably 52-59%.

[0018] According to this invention, the total Re molar amount refers to the total number of moles of rhenium (Re) in the carrier. The total Ag molar amount refers to the total number of moles of silver (Ag) in the carrier.

[0019] According to some embodiments of the present invention, based on the total mass of Al2O3 and Al(OH)3, the mass content of Re element in the support is 0.2-15wt%, for example, 0.2wt%, 0.5wt%, 1wt%, 2wt%, 4wt%, 5wt%, 10wt%, 15wt%, and any value within any range of any two values, preferably 4-12wt%.

[0020] According to some embodiments of the present invention, based on the total mass of Al2O3 and Al(OH)3, the mass content of Ag element in the carrier is 0.2-15 wt%, for example, 0.2 wt%, 0.5 wt%, 1 wt%, 2 wt%, 4 wt%, 5 wt%, 10 wt%, 15 wt%, and any value within any range of any two values, preferably 2-10 wt%.

[0021] According to some embodiments of the present invention, based on the total mass of Al2O3 and Al(OH)3, the mass content of Al(OH)3 in the carrier is <10wt%.

[0022] According to the present invention, by controlling elemental Ag, Ag₂O, elemental Re, and ReO... x The mass content is within the above range, which enables the desulfurizer to have desulfurization ability at a lower temperature, so as to better remove trace sulfur compounds from the C3 fraction of crude oil cracking gas.

[0023] According to some embodiments of the present invention, the crystal forms of Al2O3 include θ phase and γ phase; wherein, based on the total mass of Al2O3, the mass content of θ phase is <20wt% and the mass content of γ phase is <70wt%.

[0024] According to the present invention, the carrier is composed of Al2O3, Al(OH)3, Ag, Ag2O, Re and ReO. x The carrier contains Ag, Ag₂O, Re, and ReO. x It is uniformly distributed with Al2O3 and Al(OH)3; among which, Ag and Re are in elemental form, Ag2O and ReO x It is in the oxidized state; the elemental form of Ag accounts for 50-60 mol% of the total Ag, and the elemental form of Re accounts for 30-45 mol% of the total Re; ReO x It is a mixture of various Re oxides, where x = n / 2, and n is 4, 6, or 7; based on the total mass of Al2O3 and Al(OH)3, the weight percentage of Ag element in the support is 0.2-15 wt%, preferably 2-10 wt%; and the weight percentage of Re element is 0.2-15 wt%, preferably 4-12 wt%.

[0025] According to the present invention, the content of each element can be calculated based on the feed ratio, or it can be obtained by commonly used detection methods in the field, such as ICP-OES (inductively coupled plasma optical emission spectrometry).

[0026] According to some embodiments of the present invention, based on the total mass of Al2O3 and Al(OH)3, the mass content of the main active component is 1-30 wt%, preferably 5-25 wt%, and more preferably 10-20 wt%.

[0027] According to some embodiments of the present invention, the main active component is selected from one or more of Li, Na, K, Cs, Mg and Ca.

[0028] According to some embodiments of the present invention, the desulfurizing agent further includes an active component loaded on the carrier, wherein the active component is selected from one or more of Group VIII elements, Group IIIA elements, Group IB elements (excluding Ag), Group IIB elements, Group IIIB elements, Group VIIB elements (excluding Re), and rare earth elements.

[0029] According to some embodiments of the present invention, the co-active component is selected from one or more of Ga, In, La, Ni, Zn, Fe, Ce, Y and Mn.

[0030] According to some embodiments of the present invention, based on the total mass of Al2O3 and Al(OH)3, the mass content of the co-active component is 0-20 wt%, preferably 2-15 wt%, and more preferably 5-15 wt%.

[0031] According to some embodiments of the present invention, the specific surface area of ​​the carrier is 100-500 m². 2 / g, preferably 200-450m 2 / g, more preferably 250-400m 2 / g.

[0032] The present invention also provides a method for preparing the aforementioned supported desulfurizing agent, which includes the following steps:

[0033] Step 1: Mix the powdered raw material with an acidic aqueous solution, knead and shape it, and then perform a first drying and a first calcination to obtain a carrier; wherein, the powdered raw material includes alumina powder and one or more powders selected from silver perrhenate, silver nitrate, silver oxide and rhenium oxide;

[0034] Step 2: Load the precursor of the main active component and the precursor of the optional auxiliary active component onto the support obtained in Step 1, perform a second drying and a second calcination, and then perform reduction.

[0035] According to some embodiments of the present invention, the alumina powder is selected from boehmite powder and optionally alumina powder.

[0036] According to some embodiments of the present invention, the alumina powder is obtained by calcining boehmite powder at a temperature selected from 350-650°C, and the amount of alumina powder accounts for 0-20 wt% of the total mass of the alumina powder.

[0037] According to some embodiments of the present invention, the acidic aqueous solution is a mixed aqueous solution of perrhenic acid and other acids; the other acids are selected from one or more of nitric acid, acetic acid, oxalic acid and citric acid.

[0038] According to some embodiments of the present invention, the weight ratio of perrhenic acid to other acids is (0.1-10):1.

[0039] According to some embodiments of the present invention, the weight ratio of the acidic aqueous solution to the powdered raw material is (0.4-2):1.

[0040] According to some embodiments of the present invention, the method for preparing silver perrhenate includes: adding silver nitrate solution to an acidic solution of perrhenic acid or an ammonium perrhenate solution to produce a white precipitate;

[0041] Specifically, the preparation method of the silver perrhenate includes the following steps: (1) preparing an acidic solution of perrhenic acid or an ammonium perrhenate solution; (2) under stirring conditions at 30-50°C, adding silver nitrate solution dropwise to the prepared acidic solution of perrhenic acid or ammonium perrhenate solution, producing a white precipitate, until all the silver nitrate solution has been added. After standing for 30 minutes, heating is stopped, and the mixture is allowed to cool to room temperature; (3) the filtrate is removed, washed, and vacuum dried for later use. The molar ratio of silver nitrate to perrhenic acid or ammonium perrhenate is 1:1, and the acidic solution is a nitric acid solution.

[0042] According to some embodiments of the present invention, the powdered raw material further includes a forming and pore-forming agent; the amount of the forming and pore-forming agent is 0-10 wt% of the total mass of the alumina powder.

[0043] According to some embodiments of the present invention, the molding and pore-forming agent is selected from one or more of guar gum powder, starch, cellulose, urea, ethylenediamine and polymers.

[0044] According to some embodiments of the present invention, the cellulose is selected from one or more of methylcellulose, hydroxypropyl methylcellulose and sodium hydroxymethylcellulose.

[0045] According to some embodiments of the present invention, the polymer is selected from one or more of polyethylene microspheres, polystyrene, polyvinyl alcohol, and polyethylene glycol.

[0046] According to some embodiments of the present invention, the temperature of the first drying is 60-140°C, and the time is 8-24 hours.

[0047] According to some embodiments of the present invention, the temperature of the first calcination is 350-600°C, preferably 400-500°C; the time is 2-12 hours, preferably 4-10 hours; and the pressure is 2-5 MPa, preferably 3-4 MPa.

[0048] According to some embodiments of the present invention, the atmosphere of the first calcination is selected from at least one of an inert gas, nitrogen and air; preferably, the oxygen content in the atmosphere is 0-40 wt%, more preferably 15-25 wt%.

[0049] According to some embodiments of the present invention, the temperature of the second drying is 60-150°C.

[0050] According to some embodiments of the present invention, the temperature of the second calcination is 300-550°C.

[0051] According to some embodiments of the present invention, the atmosphere for the second calcination is selected from at least one of an inert gas, nitrogen, and air.

[0052] According to some embodiments of the present invention, the reduction temperature is 150-200℃, preferably 160-180℃; the temperature fluctuation range is ±2℃, preferably ±1℃; and the time is less than 45min.

[0053] According to some embodiments of the present invention, the gas used for reduction includes hydrogen and other gases, the other gases being nitrogen and / or methane, and the volume content of hydrogen being 1-5%.

[0054] According to some embodiments of the present invention, the alkali metal and / or alkaline earth metal is loaded in the form of a solution containing a precursor of the alkali metal and / or alkaline earth metal; the co-activating component is loaded in the form of a solution containing a precursor of the co-activating component, and the loading method is impregnation.

[0055] According to some embodiments of the present invention, the alkali metal and / or alkaline earth metal precursor is selected from at least one of alkali metal and / or alkaline earth metal carbonates, halides, acetates, citrates, hydroxides, and organic compounds.

[0056] According to some embodiments of the present invention, the precursor of the co-active component is selected from at least one of the halides, nitrates, acetates, carbonates, sulfates, hydroxides, ammonides, and organometallic compounds of the co-active component.

[0057] According to some embodiments of the present invention, the C3 fraction of the cracked gas contains a sulfur-containing compound selected from at least one of dimethyl sulfide, diethyl sulfide, methyl ethyl sulfide, methanethiol, and ethyl mercaptan.

[0058] According to some embodiments of the present invention, the total molar content of sulfides in the C3 fraction of the cracked gas is 0-15 ppm, preferably 2-8 ppm; the total molar content of thiols is 0-15 ppm, preferably 2-8 ppm.

[0059] According to some embodiments of the present invention, the C3 fraction of the crude oil cracked gas contains propane, propylene, propadiene, propyne and C4 fraction.

[0060] According to some embodiments of the present invention, in the C3 fraction of the crude oil cracked gas, the molar content of propane is 3-7 mol%, the molar content of propylene is 80-95 mol%, the molar content of propadiene is 0.2-2 mol%, the molar content of propyne is 0.3-3 mol%, and the molar content of C4 fraction is 0.01-0.05 mol.

[0061] According to some embodiments of the present invention, the C3 fraction of the crude oil cracking gas is derived from the top of the propane stripper in a sequential process or the top of the propane stripper in a pre-ethane stripper process.

[0062] According to some embodiments of the present invention, the contact is carried out in an isothermal bed and / or adiabatic bed reactor loaded with the supported desulfurizing agent.

[0063] According to some embodiments of the present invention, the contact temperature is 20-60°C, preferably 30-50°C; the pressure is 1-4 MPa, preferably 1.5-3 MPa; and the liquid hourly space velocity is 30-100 h⁻¹. -1 Preferably 50-80h -1 .

[0064] According to the present invention, the contact conditions are such that the sulfur content at the reactor outlet is below 0.5 ppm (mol).

[0065] According to the present invention, the temperature of the contact is the reactor inlet temperature.

[0066] In this invention, unless otherwise specified, the reaction temperature refers to the reactor inlet temperature.

[0067] According to some embodiments of the present invention, the molar content of sulfur-containing compounds in the C3 fraction of the desulfurized pyrolysis gas, calculated as sulfur element, is below 0.5 ppm.

[0068] According to the present invention, the molar content of sulfur-containing compounds before and after desulfurization treatment refers to the sulfur content at the reactor inlet and the sulfur content at the reactor outlet, respectively.

[0069] According to this invention, unless otherwise specified, the sulfur content of sulfur-containing compounds in this invention is expressed as elemental sulfur.

[0070] The method of this invention can effectively remove low-carbon sulfides and / or low-carbon mercaptans from the C3 fraction of crude oil cracked gas. The removal temperature is low, the process is simple, it will not trigger additional reactions, it will not affect the downstream hydrogenation and separation processes, and it saves energy. Moreover, the desulfurizing agent can be repeatedly regenerated and has the ability to operate stably for a long period of time.

[0071] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0072] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0073] Unless otherwise specified in the following examples and comparative examples, all conditions were performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available products.

[0074] The pseudoboehmite powder used below was purchased from Sinopec Catalysts (Beijing) Co., Ltd., with a specific surface area of ​​250 m². 2 / g or more.

[0075] Preparation Example

[0076] Dissolve 100g of silver nitrate in 200ml of deionized water. Dissolve 150g of ammonium perrhenate in 500ml of deionized water. Under stirring at 40℃, slowly add the silver nitrate aqueous solution, producing a white precipitate. After all the solution has been added, let it stand for 30 minutes, then stop adding and cool to room temperature. Remove the filtrate, wash the white precipitate three times with ether, and dry it under vacuum at 80℃ to obtain silver perrhenate.

[0077] Example 1

[0078] 1) Weigh 278g of boehmite powder, 14.9g of silver perrhenate prepared in the preparation example, 2.4g of silver nitrate, 8g of guar gum powder, 7g of sodium carboxymethyl cellulose, and 2g of polyvinyl alcohol, and mix them in a mixer to obtain a uniform powdered raw material.

[0079] 2) Weigh 4g of acetic acid and 11.2g of 75% perrhenic acid and add them to 290g of deionized water to prepare an acidic aqueous solution;

[0080] 3) Transfer the powdered raw material obtained in step (1) into a kneader, slowly add the acidic aqueous solution prepared in step (2), knead for 45 min, then extrude and pelletize to obtain toothed spherical carrier particles with a particle size of 4-5 mm; dry at 120℃ for 8 h; calcine at 420℃ for 4 h under an air atmosphere at a pressure of 3 MPa to obtain the carrier; based on the total mass of Al2O3 and Al(OH)3, the content of Ag element is 3 wt% and the content of Re element is 7 wt%;

[0081] 4) Prepare 190 mL of cerium nitrate aqueous solution containing 24 g Ce, immerse the above-obtained carrier in the solution, dry at 100 °C for 12 h, and calcine at 430 °C for 4 h to obtain desulfurizing agent precursor ①;

[0082] 5) Prepare 200 mL of potassium carbonate aqueous solution containing 26 g K, immerse desulfurizing agent precursor ① in the solution, dry at 100 °C for 12 h, and calcine at 430 °C for 4 h to obtain desulfurizing agent precursor ②;

[0083] 6) Use a mixture of hydrogen and nitrogen containing 2% hydrogen to reduce the desulfurizing agent precursor ② at 180℃ for 20 min, with the temperature controlled within ±1℃, to obtain the desulfurizing agent, denoted as A-1; based on the total mass of Al2O3 and Al(OH)3, the content of K element is 13wt%, the content of Ce element is 12wt%, the content of Ag element is 3wt%, and the content of Re element is 7wt%.

[0084] The X-ray photoelectron spectroscopy (XPS) of Re in the carrier of the desulfurizing agent A-1 prepared above is as follows: Figure 1 As shown, from Figure 1 It can be seen that the Re in the carrier consists of elemental Re and various ReO groups. x The composition includes ReO2, ReO3, and Re7O2, of which elemental Re accounts for 37.9 mol% of the total Re molar content.

[0085] X-ray photoelectron spectroscopy (XPS) of Ag in the carrier of the desulfurizing agent A-1 prepared above, as shown... Figure 2 As shown, from Figure 2 It can be seen that the Ag in the carrier is composed of elemental Ag and Ag₂O, wherein the molar content of elemental Ag accounts for 52.7 mol% of the total Ag molar content.

[0086] Example 2

[0087] 1) Prepare the carrier according to steps (1)-(3) in Example 1;

[0088] 2) Prepare 185 mL of zinc nitrate aqueous solution containing 10 g Zn, immerse the above-obtained carrier in the solution, dry at 110 °C for 10 h, and calcine at 400 °C for 6 h to obtain desulfurizing agent precursor ①;

[0089] 3) Prepare 200 mL of sodium carbonate aqueous solution containing 30 g Na, immerse the desulfurizing agent precursor ① in the solution, dry at 110 °C for 10 h, and calcine at 400 °C for 6 h to obtain the desulfurizing agent precursor ②;

[0090] 4) Use a mixture of hydrogen and nitrogen containing 2% hydrogen to reduce the desulfurizing agent precursor ② at 160℃ for 30 min, with the temperature controlled within ±1℃, to obtain the desulfurizing agent, denoted as A-2; based on the total mass of Al2O3 and Al(OH)3, the content of Na element is 15wt%, the content of Zn element is 5wt%, the content of Ag element is 3wt%, and the content of Re element is 7wt%.

[0091] Example 3

[0092] 1) Weigh 285g of boehmite powder, 19.4g of silver perrhenate prepared in the preparation example, 5g of silver nitrate, 6.1g of rhenium dioxide, 4.5g of guar gum powder, 12g of hydroxypropyl methylcellulose, and 3g of polyethylene microspheres, and mix them in a mixer to obtain a uniform powdered raw material.

[0093] 2) Weigh 10g of acetic acid and 4.9g of 75% perrhenic acid and add them to 310g of deionized water to prepare an acidic aqueous solution;

[0094] 3) Transfer the powdered raw material obtained in step (1) into a kneader, slowly add the acidic aqueous solution prepared in step (2), knead for 30 min, then extrude and pelletize to obtain spherical carrier particles with a particle size of 4-5 mm; dry at 110℃ for 10 h; calcine at 450℃ for 4 h in a nitrogen-oxygen mixed atmosphere with a pressure of 2.5 MPa and an oxygen content of 15% to obtain the carrier; based on the total mass of Al2O3 and Al(OH)3, the content of Ag element is 4.5 wt% and the content of Re element is 9 wt%;

[0095] 4) Prepare 200 mL of potassium hydroxide aqueous solution containing 20 g K, immerse the above-obtained carrier in the solution, dry at 130 °C for 6 h, and calcine at 350 °C for 4 h to obtain the desulfurizing agent precursor;

[0096] 5) Use a mixture of hydrogen and nitrogen containing 3% hydrogen to reduce the desulfurizing agent precursor at 170℃ for 15 min, with the temperature controlled within ±1℃, to obtain the desulfurizing agent, denoted as A-3; based on the total mass of Al2O3 and Al(OH)3, the content of K element is 10wt%, the content of Ag element is 4.5wt%, and the content of Re element is 9wt%.

[0097] Example 4

[0098] 1) Prepare the carrier according to the method of steps (1)-(3) in Example 3;

[0099] 2) Prepare 195 mL of gallium nitrate aqueous solution containing 7 g Ga, immerse the above-obtained support in the solution, dry at 120 °C for 8 h, and calcine at 450 °C for 4 h to obtain desulfurizing agent precursor ①;

[0100] 3) Prepare 200 mL of magnesium nitrate aqueous solution containing 20 g Mg, immerse desulfurizing agent precursor ① in the solution, dry at 120 °C for 8 h, and calcine at 450 °C for 4 h to obtain desulfurizing agent precursor ②;

[0101] 4) Use a mixture of hydrogen and methane containing 1% hydrogen to reduce the desulfurizing agent precursor ② at 150℃ for 25 min, with the temperature controlled within ±1℃, to obtain the desulfurizing agent, denoted as A-4; based on the total mass of Al2O3 and Al(OH)3, the content of Mg element is 10wt%, the content of Ga element is 3.5wt%, the content of Ag element is 4.5wt%, and the content of Re element is 9wt%.

[0102] Example 5

[0103] 1) Weigh 285g of boehmite powder, 18.2g of silver perrhenate prepared in the preparation example, 17.3g of silver nitrate, 5.9g of silver oxide, 2.6g of rhenium dioxide, 5g of guar gum powder, 10g of methylcellulose, and 4g of polystyrene. Mix them in a mixer to obtain a uniform powdered raw material.

[0104] 2) Weigh 10g of citric acid and 4g of 75% perrhenic acid and add them to 315g of deionized water to prepare an acidic aqueous solution;

[0105] 3) Transfer the powdered raw material obtained in step (1) into a kneader, slowly add the acidic aqueous solution prepared in step (2), knead for 45 min, then extrude and pelletize to obtain columnar carrier particles with a particle size of 3-4 mm; dry at 130℃ for 6 h; calcine at 430℃ for 4 h in a nitrogen-oxygen mixed atmosphere with a pressure of 2.5 MPa and an oxygen content of 30% to obtain the carrier; based on the total mass of Al2O3 and Al(OH)3, the content of Ag element is 11 wt% and the content of Re element is 7 wt%;

[0106] 4) Prepare 190 mL of lanthanum nitrate aqueous solution containing 8 g La, immerse the above-obtained support in the solution, dry at 110 °C for 10 h, and calcine at 450 °C for 4 h to obtain desulfurizing agent precursor ①;

[0107] 5) Prepare 200 mL of cesium carbonate aqueous solution containing 10 g Cs, immerse the desulfurizing agent precursor ① in the solution, dry at 110 °C for 10 h, and calcine at 380 °C for 6 h to obtain the desulfurizing agent precursor ②;

[0108] 6) Use a mixture of hydrogen and nitrogen containing 2% hydrogen to reduce the desulfurizing agent precursor ② at 170℃ for 35 minutes, with the temperature controlled within ±1℃, to obtain the desulfurizing agent, denoted as A-5; based on the total mass of Al2O3 and Al(OH)3, the content of Cs element is 5wt%, the content of La element is 4wt%, the content of Ag element is 11wt%, and the content of Re element is 7wt%.

[0109] Example 6

[0110] 1) Weigh 274g of boehmite powder, 10.8g of silver perrhenate prepared in the preparation example, 2.7g of silver nitrate, 1.6g of rhenium trioxide, 8g of starch, 5g of methylcellulose, and 4g of polyethylene microspheres, and mix them in a mixer to obtain a uniform powdered raw material.

[0111] 2) Weigh 12g of citric acid and 2.0g of 75% perrhenic acid and add them to 295g of deionized water to prepare an acidic aqueous solution;

[0112] 3) Transfer the powdered raw material obtained in step (1) into a kneader, slowly add the acidic aqueous solution prepared in step (2), knead for 1 hour, then extrude and pelletize to obtain toothed spherical carrier particles with a particle size of 3-4 mm; dry at 120℃ for 8 hours; calcine at 400℃ for 6 hours in a nitrogen-oxygen mixed atmosphere with a pressure of 3.5 MPa and an oxygen content of 25% to obtain the carrier; based on the total mass of Al2O3 and Al(OH)3, the content of Ag element is 2.5 wt% and the content of Re element is 4 wt%;

[0113] 4) Prepare 200 mL of an aqueous solution containing 6 g In of indium nitrate, immerse the above-obtained carrier in the solution, dry at 150 °C for 4 h, and calcine at 420 °C for 4 h to obtain the desulfurizing agent precursor ①;

[0114] 5) Prepare 200 mL of calcium bicarbonate aqueous solution containing 12 g Ca, immerse desulfurizing agent precursor ① in the solution, dry at 150 °C for 4 h, and calcine at 300 °C for 6 h to obtain desulfurizing agent precursor ②;

[0115] 6) Use a mixture of hydrogen and nitrogen containing 1% hydrogen to reduce the desulfurizing agent precursor ② at 160℃ for 25 min, with the temperature controlled within ±1℃, to obtain the desulfurizing agent, denoted as A-6; based on the total mass of Al2O3 and Al(OH)3, the content of Ca element is 6wt%, the content of In element is 3wt%, the content of Ag element is 2.5wt%, and the content of Re element is 4wt%.

[0116] Comparative Example 1

[0117] 1) Weigh 285g of boehmite powder, 7.5g of silver oxide, 11.7g of rhenium dioxide, 10g of starch, 4g of methylcellulose, and 3g of polyethylene microspheres, and mix them in a mixer to obtain a uniform powdered raw material.

[0118] 2) Weigh 12g of citric acid and add it to 300g of deionized water to prepare an acidic aqueous solution;

[0119] 3) Transfer the powdered raw material obtained in step (1) into a kneader, slowly add the acidic aqueous solution prepared in step (2), knead for 1 hour, then extrude and pelletize to obtain toothed spherical carrier particles with a particle size of 3-4 mm; dry at 120℃ for 8 hours; calcine at 450℃ for 6 hours under normal pressure and air atmosphere to obtain the carrier; based on the total mass of Al2O3 and Al(OH)3, the content of Ag element is 3.5 wt% and the content of Re element is 5 wt%;

[0120] 4) Prepare 200 mL of potassium carbonate aqueous solution containing 10 g K, immerse the carrier in the solution, dry at 100 °C for 12 h, and calcine at 320 °C for 4 h to obtain the desulfurizing agent precursor;

[0121] 5) The desulfurizing agent precursor was reduced at 180°C for 1.5 h using a mixture of nitrogen and hydrogen containing 5% hydrogen to obtain the desulfurizing agent, denoted as R-1; based on the total mass of Al2O3 and Al(OH)3, the content of K element was 5wt%, the content of Ag element was 3.5wt%, and the content of Re element was 5wt%.

[0122] Comparative Example 2

[0123] 1) Weigh 295g of boehmite powder, 8g of guar gum powder, and 10g of starch, and mix them in a mixer to obtain a uniform powdered raw material.

[0124] 2) Weigh 5g of concentrated nitric acid and add it to 300g of deionized water to prepare an acidic aqueous solution;

[0125] 3) Transfer the powdered raw material obtained in step (1) into a kneader, slowly add the acidic aqueous solution prepared in step (2), knead for 45 min, then extrude and pelletize to obtain columnar carrier particles with a particle size of 4-5 mm; dry at 110℃ for 10 h; calcine at 500℃ for 4 h under normal pressure and air atmosphere to obtain the carrier.

[0126] 4) Prepare 200 mL of silver nitrate aqueous solution containing 6 g Ag, immerse the carrier in the solution, dry at 120 °C for 8 h, and calcine at 450 °C for 6 h to obtain desulfurizing agent precursor ①;

[0127] 5) Prepare 200 mL of potassium hydroxide aqueous solution containing 18 g K, immerse the desulfurizing agent precursor ① in the solution, dry at 120 °C for 8 h, and calcine at 450 °C for 6 h to obtain the desulfurizing agent precursor ②;

[0128] 6) Use a mixture of nitrogen and hydrogen containing 5% hydrogen to reduce the desulfurizing agent precursor ② at 180℃ for 1.5h, with the temperature controlled within ±1℃, to obtain the desulfurizing agent, denoted as R-2; based on the total mass of Al2O3 and Al(OH)3, the K element content is 9wt% and the Ag element content is 3wt%.

[0129] The desulfurizing agents prepared in Examples 1-6 and Comparative Examples 1-2 were subjected to X-ray photoelectron spectroscopy (XPS) tests. The Ag and Re valence states were determined based on the test results, and the percentage of each valence state was calculated.

[0130] Table 1 Valence states and percentage distributions of Ag and Re.

[0131]

[0132] As can be seen from the data in Table 1, in the desulfurizers prepared in Examples 1-6, the molar content of elemental Re accounts for 30-45% of the total molar content of Re. However, in the desulfurizer R-1 prepared in Comparative Example 1, the molar content of elemental Re accounts for 86.8% of the total molar content of Re. The desulfurizer R-2 prepared in Comparative Example 2 does not contain elemental Re or ReO. x .

[0133] Test case

[0134] This test case is used to illustrate the evaluation of desulfurization effectiveness.

[0135] The trace sulfur removal process for the C3 fraction from the top of the deethaner column utilizes a single-stage adiabatic fixed-bed reactor. The liquid hourly space velocity (LHSV) is 60 h⁻¹. -1The pressure is 2.5 MPa; the composition of the C3 fraction of the cracked gas at the reactor inlet is as follows: dimethyl sulfide 3 ppm, methyl ethyl sulfide 5 ppm, methanethiol 6 ppm, propane content 5.93 mol%, propylene content 91.87 mol%, propadiene content 1.46 mol%, propyne content 0.74 mol%, C4 fraction 215 ppm, and reactor inlet temperature 46℃.

[0136] The operating cycle refers to the time the system can operate while maintaining the total sulfur content at the reactor outlet below 0.5 ppm. Total sulfur content refers to the molar content of sulfur-containing compounds in the material, expressed as elemental sulfur.

[0137] Table 2 Comparison of desulfurization performance of various desulfurizing agents

[0138]

[0139] Table 3 Comparison of reactor outlet sulfur content after 210 hours of operation for each desulfurizing agent

[0140] desulfurizer Total sulfur exported (ppm) A-1 0.6 A-2 1.1 A-3 2.7 A-4 0.0 A-5 5.9 A-6 8.5 R-1 14.1 R-2 14.4

[0141] Tables 2 and 3 compare the removal capabilities of various desulfurizing agents for low-carbon sulfides and / or low-carbon mercaptans in the C3 fraction of sulfur-containing crude oil cracked gas. The data in the tables show that, while ensuring the total sulfur content at the outlet is less than 0.5 ppm, the operating cycles of each desulfurizing agent differ; compared to Comparative Examples 1-2, the desulfurizing agents prepared in Examples 1-6 not only have longer operating times but also lower reaction temperatures. Experimental results indicate that the uniformly distributed elemental Ag, Ag2O, elemental Re, and ReO in the desulfurizing agent carrier Al2O3... x It exhibits excellent synergistic effects, and when the molar content of elemental Re accounts for 30-45% of the total molar amount of Re, it can better enhance the active component's ability to remove sulfur and extend its service life.

[0142] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for removing sulfur-containing compounds from the C3 fraction of crude oil cracked gas, characterized in that, The method includes: contacting the C3 fraction of crude oil cracked gas with a supported desulfurizing agent; wherein the supported desulfurizing agent includes a carrier and a main active component loaded on the carrier; the main active component includes alkali metals and / or alkaline earth metals; the carrier includes Al2O3, Al(OH)3, elemental Ag, Ag2O, elemental Re and ReO. x ReO x It is a mixture of various Re oxides, wherein x = n / 2, and n has a value of 4, 6, or 7; the molar content of elemental Re accounts for 30-45% of the total molar amount of Re in the carrier.

2. The method according to claim 1, wherein, The molar content of elemental Ag accounts for 50-60% of the total molar amount of Ag in the carrier.

3. The method according to claim 1 or 2, wherein, Based on the total mass of Al2O3 and Al(OH)3, the mass content of Re element in the support is 0.2-15wt%, preferably 4-12wt%. And / or, based on the total mass of Al2O3 and Al(OH)3, the mass content of Ag element in the support is 0.2-15 wt%, preferably 2-10 wt%; And / or, based on the total mass of Al2O3 and Al(OH)3, the mass content of Al(OH)3 in the support is <10wt%.

4. The method according to any one of claims 1-3, wherein, Al2O3 has two crystal forms: θ phase and / or γ phase. Based on the total mass of Al2O3, the mass content of the θ phase is <20 wt%, and the mass content of the γ phase is <70 wt%.

5. The method according to any one of claims 1-4, wherein, Based on the total mass of Al2O3 and Al(OH)3, the mass content of the main active component is 1-30 wt%, preferably 5-25 wt%, and more preferably 10-20 wt%. And / or, the main active component is selected from one or more of Li, Na, K, Cs, Mg and Ca.

6. The method according to any one of claims 1-5, wherein, The desulfurizing agent further includes an active component loaded on the carrier, the active component being selected from one or more of Group VIII elements, Group IIIA elements, Group IB elements (excluding Ag), Group IIB elements, Group IIIB elements, Group VIIB elements (excluding Re), and rare earth elements; Preferably, the auxiliary active component is selected from one or more of Ga, In, La, Ni, Zn, Fe, Ce, Y and Mn.

7. The method according to claim 6, wherein, Based on the total mass of Al2O3 and Al(OH)3, the mass content of the co-active component is 0-20 wt%, preferably 2-15 wt%, and more preferably 5-15 wt%.

8. The method according to any one of claims 1-7, wherein, The specific surface area of ​​the carrier is 100-500 m². 2 / g, preferably 200-450m 2 / g, more preferably 250-400m 2 / g.

9. The method according to any one of claims 1-8, wherein, The C3 fraction of the cracked gas contains sulfur-containing compounds, which are selected from at least one of dimethyl sulfide, diethyl sulfide, methyl ethyl sulfide, methanethiol, and ethyl mercaptan. Preferably, the total molar content of sulfides in the C3 fraction of the cracked gas is 0-15 ppm, more preferably 2-8 ppm; and the total molar content of thiols is 0-15 ppm, more preferably 2-8 ppm.

10. The method according to claim 9, wherein, The C3 fraction of the crude oil cracked gas contains propane, propylene, propadiene, propyne and C4 fraction; Preferably, in the C3 fraction of the crude oil cracked gas, the molar content of propane is 3-7 mol%, the molar content of propylene is 80-95 mol%, the molar content of propadiene is 0.2-2 mol%, the molar content of propyne is 0.3-3 mol%, and the molar content of C4 fraction is 0.01-0.05 mol.

11. The method according to any one of claims 1-10, wherein, The C3 fraction of the crude oil cracking gas comes from the top of the propane stripper in a sequential process or the top of the propane stripper in a pre-ethane stripper process.

12. The method according to any one of claims 1-11, wherein, The contact is carried out in an isothermal bed and / or adiabatic bed reactor loaded with the supported desulfurizing agent; And / or, the contact temperature is 20-60°C, preferably 30-50°C; the pressure is 1-4 MPa, preferably 1.5-3 MPa; and the liquid hourly space velocity is 30-100 h⁻¹. -1 Preferably 50-80h -1 .

13. The method according to any one of claims 1-12, wherein, The molar content of sulfur-containing compounds in the C3 fraction of the desulfurized gas, calculated as sulfur element, is below 0.5 ppm.

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