IGCC power generation syngas directional deep desulfurization catalyst, preparation method and application thereof

Abstract

This invention discloses a directional deep desulfurization catalyst for IGCC power generation syngas, its preparation method, and its application. The catalyst consists of a modified alumina support obtained by modifying alumina with metal oxides, and main and auxiliary metal phases supported on the support. The main metal phase is a Group VIB and / or Group VIII transition metal, and the auxiliary metal phase is one or more of Fe, Cu, La, and Ce. The total mass fraction of the active metal phase, calculated by metal oxides, is 10wt%–30wt%. In the preparation process, an alumina precursor is first mixed with a modifier, shaped, dried, and calcined to obtain the modified support. Then, a metal source is impregnated, followed by pretreatment under pressure, and subsequently calcined in steam and air atmospheres to obtain the finished product. This invention optimizes metal dispersion and catalyst pore structure, improves low-temperature desulfurization activity and anti-poisoning ability, and can efficiently remove difficult-to-remove organic sulfur from syngas. It is suitable for the complex operating conditions of IGCC and can also be extended to naphtha hydrorefining, showing promising industrial application prospects.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation technology, specifically relating to a directional deep desulfurization catalyst for IGCC power generation syngas, its preparation method, and its application. Background Technology

[0002] Integrated gasification combined cycle (IGCC) power generation technology is of great significance to my country's energy transition and sustainable development. By efficiently gasifying and deeply purifying coal for combined cycle power generation, it increases the power supply efficiency of traditional coal-fired power plants to 41%-46%, reduces pollutant emissions to 10% of conventional technologies, and achieves a sulfide removal rate of over 99%. This successfully addresses the clean energy dilemma faced by my country, which is characterized by abundant coal, scarce oil, and limited gas resources. Currently, my country's IGCC technology standards have been exported to the European and American markets (such as the 600 MW IDGCC project in Australia), and 40% of projects under construction globally adopt the Chinese solution. This not only enhances my country's international influence in the clean energy field but also provides a strategic technological path that combines efficient power generation with low-carbon transformation for the construction of new power systems and ensuring energy security under the "dual carbon" goal.

[0003] However, in the actual industrial application of IGCC, the deep desulfurization of syngas still faces insurmountable technical bottlenecks, becoming the core issue restricting the stable and efficient operation of the IGCC system. Incomplete decomposition of organic sulfur during the coal gasification stage, coupled with the performance limitations of existing organic sulfur hydrolysis catalysts, and the interference from complex gas components such as O2, H2O, H2, and H2S in the IGCC syngas system, results in trace amounts of difficult-to-remove organic sulfur (mainly thiols and sulfides, with a content of approximately 5 mg / Nm³) remaining in the syngas. 3 Furthermore, carbonyl sulfide (COS) is chemically stable and cannot be effectively removed by conventional absorbents.

[0004] Currently available syngas desulfurization catalysts are mainly alumina-based and titanium dioxide-based hydrodesulfurization catalysts, and the active components for hydrodesulfurization are mostly selected from... Transition metals such as Mo and W from Group 1 and Co, Ni, Pt, and Pd from Group VIII are used. Among them, alumina-based catalysts have become the mainstream in industry due to their large specific surface area and low cost, but they have fatal defects such as extremely poor resistance to sulfation and easy poisoning and deactivation. In addition, their low-temperature desulfurization activity is insufficient and cannot meet the operating conditions of IGCC syngas. Titanium oxide-based catalysts have excellent low-temperature activity and resistance to poisoning, but when used alone as a support, their structural integrity is poor and their mechanical stability is insufficient, making it difficult to meet the requirements of continuous industrial operation.

[0005] To improve catalyst performance, existing technologies mostly focus on adjusting the properties of the support to promote the dispersion of active metals and enhance resistance to poisoning. However, the core technical problems remain unresolved: First, the interaction between the metal and the support in traditional catalysts is not well regulated, leading to the easy aggregation and poor dispersibility of active metals, resulting in low metal utilization, insufficient hydrodesulfurization activity, and inability to achieve deep removal of trace organic sulfur. Second, the pore structure design of the catalyst is unreasonable, hindering the diffusion of reactant and product molecules, easily causing carbon deposition and deactivation, and resulting in a short service life. Third, the catalyst is not designed specifically for the complex gas-phase system of IGCC, making it difficult to simultaneously achieve low-temperature desulfurization performance, anti-interference ability, and structural stability, thus failing to meet the industrial requirements for directional deep fine desulfurization of IGCC syngas. Summary of the Invention

[0006] Based on previous research and existing problems, this invention proposes a directional deep desulfurization catalyst for IGCC power generation syngas, its preparation method, and its application after further research and analysis.

[0007] To achieve the above objectives, the present invention provides the following technical solution: An IGCC power generation directional deep desulfurization catalyst for syngas is characterized in that the catalyst comprises a modified alumina support and a metal active phase supported on the support; The modified alumina carrier is obtained by modifying alumina with metal oxides; The active metal phase comprises a host metal phase and a complementary metal phase. The host metal phase is a group VIB and / or group VIII transition metal, and the complementary metal phase is one or more of Fe, Cu, La, and Ce. The total mass fraction of the active metal phase, calculated based on metal oxides, is 10 wt% to 30 wt%.

[0008] Preferably, the metal oxide of the modified alumina is one or more of zirconium oxide, zinc oxide, and titanium oxide, and the mass of the metal oxide accounts for 5 wt% to 15 wt% of the mass of the alumina. The modified alumina carrier has a specific surface area of ​​150–350 m² / g, a pore volume of 0.5–2.5 mL / g, and a pore size concentrated in the range of 2–18 nm.

[0009] Preferably, the ratio of metal atoms in the main metal phase to the auxiliary metal phase is 1:1 to 4:1; The main metal phase is one or more of Ni, Mo, and Co. When the main metal phase includes Ni and Mo, the ratio of Ni to Mo metal atoms is 0.5:1 to 2.5:1.

[0010] This invention also proposes a method for preparing the directional deep desulfurization catalyst for IGCC power generation syngas as mentioned above, specifically including the following steps: S1. The alumina precursor is mixed with a metal oxide modifier, and then molded, dried and calcined to obtain a modified alumina carrier. S2. The impregnation solution containing the main metal phase source and the auxiliary metal phase source is loaded onto the modified alumina support, and after pretreatment under pressure, it is calcined in a steam atmosphere and then in an air atmosphere to obtain the catalyst.

[0011] Preferably, the alumina precursor in S1 is aluminum hydroxide dry gel; The mixing process involves ball milling aluminum hydroxide dry adhesive and metal oxide modifier separately, and then kneading them together with adhesive solvent and extrusion aid. The solvent for the adhesive is an organic acid and / or an inorganic acid; The extrusion aid is guar gum powder, and the amount of guar gum powder used is 1 to 5 wt% of the mass of the modified alumina carrier precursor.

[0012] Preferably, the adhesive solvent in S1 is one or more of nitric acid, carbonic acid, sulfuric acid, acetic acid, and tartaric acid, and the amount used is 1wt% to 3wt% by mass. Drying temperature 70-180℃, time 2-5 hours, calcination temperature 300-600℃, time 4-8 hours.

[0013] Preferably, the load in S2 is an equal-volume impregnation; The atmosphere for pressurized pretreatment is water vapor or ammonia, with a pretreatment temperature of 120~350℃, a time of 1~5 hours, and a pressure of 0.3~2.5MPa.

[0014] Preferably, the main metal phase metal source in S2 is one or more of water-soluble Ni source, water-soluble Mo source, and water-soluble Co source; The auxiliary metal source is one or more of the following: water-soluble Fe source, water-soluble Cu source, water-soluble La source, and water-soluble Ce source.

[0015] Preferably, in S2, the steam atmosphere calcination temperature is 250–550°C and the time is 4–9 hours; the air atmosphere calcination temperature is 400–600°C and the time is 3–8 hours.

[0016] In addition, the present invention also proposes an application of a catalyst for directional deep desulfurization of syngas in IGCC power generation, characterized in that the catalyst is used in the deep desulfurization reaction of syngas hydrogenation in IGCC power generation technology, and can also be used in the hydrorefining and desulfurization reaction of naphtha.

[0017] Compared with existing technologies, this invention provides a directional deep desulfurization catalyst for IGCC power generation syngas, its preparation method, and its application, which has the following beneficial effects: This invention modifies the metal-support interaction through the electronic effect of the support modifier, weakening the Mo-S bond energy and significantly improving the low-temperature desulfurization activity of the catalyst. It can efficiently remove stable organic sulfur compounds such as COS, thiols, and thioethers from IGCC syngas that are difficult to treat by traditional methods. The sulfur content of the syngas after desulfurization can be reduced to <0.03 μg. g - ¹ It is far superior to traditional catalysts, completely solving the technical problem that trace amounts of organic sulfur in syngas cannot be removed by conventional absorbents, and meeting the stringent requirements of deep desulfurization in IGCC systems.

[0018] The preparation process, which involves pressurized pretreatment in a steam / ammonia atmosphere, effectively regulates the interaction between the metal and the support. Combined with the structural control of the modified alumina support, this allows high-content active metals to be uniformly dispersed in the form of nano-sized microcrystals on the surface and within the pores of the support, without significant agglomeration. This successfully overcomes the industry problem of poor dispersibility in high-metal-content catalysts and significantly improves the utilization rate of active metals. At the same time, it promotes the formation of highly active hydrodesulfurization phases such as NiMoS, significantly enhancing the hydrogenation activity of the catalyst and achieving efficient hydrogenation conversion of organic sulfur.

[0019] Modified supports based on alumina retain the advantages of alumina's high specific surface area and excellent mechanical stability. Furthermore, modifications using zirconium oxide, zinc oxide, and titanium oxide compensate for the structural integrity deficiencies of single-modifier supports, enhancing the catalyst's resistance to sulfation and poisoning, and preventing structural collapse due to poisoning. On the other hand, the modified alumina support forms a mesoporous structure with uniform pore size and large pore volume, facilitating the diffusion of reactant and product molecules, reducing the impact of carbon deposition on hydrogenation activity, significantly slowing catalyst deactivation rates, and substantially extending catalyst lifespan. This reduces catalyst replacement frequency and maintenance costs in industrial applications. Attached Figure Description

[0020] Figure 1 The image shows the oxidation state XRD pattern of the IGCC power generation syngas directional deep desulfurization catalyst in Example 2 of this invention. Figure 2 This is an XPS characterization analysis diagram of the IGCC power generation syngas directional deep desulfurization catalyst in Example 2 of the present invention; Figure 3 This is a TEM characterization analysis diagram of the IGCC power generation syngas directional deep desulfurization catalyst in Example 2 of the present invention. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1 Take 1 kg of aluminum hydroxide dry adhesive and 0.120 kg of titanium dioxide and put them into a ball mill. Grind them in the ball mill to obtain aluminum hydroxide dry adhesive and carrier modifier powder respectively. Add 3 wt% of the catalyst carrier precursor powder as an extrusion aid guar gum powder, 3 wt% of the adhesive solvent nitric acid aqueous solution (2 wt%) and 80 wt% of deionized water to the aluminum oxide dry adhesive and knead it 3 to 5 times. Extrude it into shape and dry the shaped wet catalyst carrier at 120℃ for 4 hours and calcine it at 550℃ for 5 hours to obtain the shaped catalyst carrier.

[0023] Weigh out 1.11 kg of nickel nitrate (Ni(NO3)2·6H2O) and 0.34 kg of ammonium molybdate ((NH4)6Mo7O). 24 ·4H2O), 0.39 kg cobalt nitrate (Co(NO3)2·6H2O).

[0024] Ammonium molybdate, nickel nitrate, and cobalt nitrate were added to an appropriate amount of water and stirred at room temperature until completely dissolved. The solution was then brought to a final volume of 1 L to obtain impregnation solution A.

[0025] 1 L of impregnation solution A was added to the carrier precursor based on the mass of modified alumina. After impregnation, the resulting catalyst was placed in a hydrothermal reactor for hydrothermal treatment at 170 °C for 3 hours and at a pressure of 1.0 MPa.

[0026] The wet-formed hydrogenation catalyst was calcined twice. The first calcination conditions were: water vapor atmosphere, calcination temperature of 500℃, and calcination time of 5 hours, to obtain an mesophase catalyst. The mesophase catalyst was then calcined a second time under the following conditions: air atmosphere, calcination temperature of 500℃, and calcination time of 5 hours, to obtain a shaped catalyst.

[0027] Example 2 Take 1 kg of aluminum hydroxide dry adhesive and 0.120 kg of titanium dioxide and put them into a ball mill. Grind them in the ball mill to obtain aluminum hydroxide dry adhesive and carrier modifier powder respectively. Add 3 wt% of the catalyst carrier precursor powder as an extrusion aid guar gum powder, 3 wt% of the adhesive solvent nitric acid aqueous solution (2 wt%) and 80 wt% of deionized water to the aluminum oxide dry adhesive and knead it 3 to 5 times. Extrude it into shape and dry the shaped wet catalyst carrier at 120℃ for 4 hours and calcine it at 550℃ for 5 hours to obtain the shaped catalyst carrier.

[0028] Weigh out 1.11 kg of nickel nitrate (Ni(NO3)2·6H2O) and 0.34 kg of ammonium molybdate ((NH4)6Mo7O). 24 ·4H2O), 0.39 kg cobalt nitrate (Co(NO3)2·6H2O).

[0029] Ammonium molybdate, nickel nitrate, and cobalt nitrate were added to an appropriate amount of water and stirred at room temperature until completely dissolved. The solution was then brought to a final volume of 1 L to obtain impregnation solution A.

[0030] 1 L of impregnation solution A was added to the carrier precursor based on the mass of modified alumina. After impregnation, the resulting catalyst was treated with ammonia gas at 170 °C for 3 hours and 1.0 MPa.

[0031] The wet-formed hydrogenation catalyst was calcined twice. The first calcination conditions were: water vapor atmosphere, calcination temperature of 500℃, and calcination time of 5 hours, to obtain an mesophase catalyst. The mesophase catalyst was then calcined a second time under the following conditions: air atmosphere, calcination temperature of 500℃, and calcination time of 5 hours, to obtain a shaped catalyst.

[0032] Example 3 Take 1 kg of aluminum hydroxide dry adhesive and 0.120 kg of titanium dioxide and put them into a ball mill. Grind them in the ball mill to obtain aluminum hydroxide dry adhesive and carrier modifier powder respectively. Add 3 wt% of the catalyst carrier precursor powder as an extrusion aid guar gum powder, 3 wt% of the adhesive solvent nitric acid aqueous solution (2 wt%) and 80 wt% of deionized water to the aluminum oxide dry adhesive and knead it 3 to 5 times. Extrude it into shape and dry the shaped wet catalyst carrier at 120℃ for 4 hours and calcine it at 550℃ for 5 hours to obtain the shaped catalyst carrier.

[0033] Weigh out 1.11 kg of nickel nitrate (Ni(NO3)2·6H2O) and 0.34 kg of ammonium molybdate ((NH4)6Mo7O). 24 ·4H2O).

[0034] Ammonium molybdate and nickel nitrate were added to an appropriate amount of water and stirred at room temperature until completely dissolved. The solution was then brought to a final volume of 1 L to obtain impregnation solution B.

[0035] 1 L of impregnation solution B was added to the carrier precursor based on the mass of modified alumina. After impregnation, the resulting catalyst was treated with ammonia gas at 170 °C for 3 hours and 1.0 MPa.

[0036] The wet-formed hydrogenation catalyst was calcined twice. The first calcination conditions were: water vapor atmosphere, calcination temperature of 500℃, and calcination time of 5 hours, to obtain an mesophase catalyst. The mesophase catalyst was then calcined a second time under the following conditions: air atmosphere, calcination temperature of 500℃, and calcination time of 5 hours, to obtain a shaped catalyst.

[0037] Comparative Example 1 Weigh out 1 kg of aluminum hydroxide dry adhesive carrier, 1.11 kg of nickel nitrate (Ni(NO3)2·6H2O), and 0.34 kg of ammonium molybdate ((NH4)6Mo7O). 24 ·4H2O), 0.39 kg cobalt nitrate (Co(NO3)2·6H2O).

[0038] Ammonium molybdate, nickel nitrate, and cobalt nitrate were added to an appropriate amount of water and stirred at room temperature until completely dissolved. The solution was then brought to a final volume of 1 L to obtain impregnation solution C.

[0039] An aluminum hydroxide dry gel carrier was impregnated into impregnation solution C using an equal-volume impregnation method. The resulting impregnated alumina carrier was dried at 120°C for 3 hours and calcined at 500°C for 4 hours to obtain a molded catalyst.

[0040] To investigate the microstructure and active metal dispersion state of the catalyst of this invention, the IGCC power generation syngas directional deep desulfurization catalyst prepared in Example 2 was used as the research object. The oxidized catalyst before the reaction was characterized by XRD, and the sulfided catalyst after the reaction was characterized by XPS and TEM. The characterization results and analysis are as follows: The oxidized catalyst before the reaction was characterized by XRD. The results showed that after the introduction of Ni, Mo and Co active metals, no obvious diffraction peaks of the metal species were observed. Only the characteristic diffraction peaks of the support Al2O3 were observed, indicating that the active metals Ni, Mo and Co have good dispersibility on the catalyst support.

[0041] XPS and TEM analyses were performed on the sulfided catalyst after the reaction. XPS results showed that ( Figure 2 -b), Mo 5+ and Mo 6+ The lower intensity of the photoelectron peak corresponding to the species indicates a higher degree of sulfidation of the active metal Mo in the catalyst. (TEM image of the catalyst) Figure 3 Further observation revealed that the MoS2 active phase is generally dispersed at the nanoscale, without obvious agglomeration or large crystals, and the active sites are fully exposed. The MoS2 sheets are relatively thin, with a stacking number of 2-4 layers. This structure is conducive to exposing more edge active sites, thereby providing abundant core active centers for the hydrodesulfurization reaction. The active phase is uniformly loaded on the support surface, ensuring effective diffusion of reactant molecules and efficient contact with active sites.

[0042] A systematic evaluation of the catalyst properties of the embodiments and comparative examples of the present invention is performed: Hydrogenation activity was evaluated for Examples 1, 2, 3, and Comparative Example 1.

[0043] The catalyst activity evaluation was conducted in a 100 mL high-pressure hydrogenation reactor. Prior to evaluation, the catalyst underwent pre-sulfurization and activity stabilization processes. The evaluation conditions were: reaction pressure 2.2 MPa, reaction temperature 130 °C, and gas hourly space velocity 5000 h⁻¹. 1 The properties of the syngas used in the activity evaluation test are shown in Table 1.

[0044] Table 1. Evaluation of the catalyst activity and syngas properties used in this invention. The catalyst activity results of the examples and comparative examples are shown in Table 2. The hydrodesulfurization activity and hydrogenation saturation activity of the catalysts were compared by analyzing the sulfur content of the hydrotreated oil and the density of the hydrotreated products. A comparison of Examples 1, 2, 3, and Comparative Example 1 revealed that the catalyst provided by this invention exhibits higher hydrogenation and desulfurization activity than the catalyst in the comparative example. This means that the highly active hydrogenation catalyst prepared by this invention provides larger and more uniformly distributed pores, overcoming the poor dispersibility of catalysts with high metal content.

[0045] Table 2. Evaluation results of catalyst reactivity in the embodiments and comparative examples of the present invention. Of course, in addition to the cases listed in the examples, other modifiers, solvents, other metal main components, auxiliary components, Ni(Co) / Mo atomic ratios, drying temperatures and times, and calcination temperatures and times are also possible when modifying the properties of the support. However, in the cases listed in the examples, the catalytic activity is higher and the pore structure is better.

[0046] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions claimed by the present invention.

Claims

1. A directional deep desulfurization catalyst for IGCC power generation syngas, characterized in that, The catalyst comprises a modified alumina support and a metal active phase supported on the support; The modified alumina carrier is obtained by modifying alumina with metal oxides; The active metal phase comprises a host metal phase and a promoter metal phase, wherein the host metal phase is... Group 1 and / or Group VIII transition metals, with the auxiliary metal phase being one or more of Fe, Cu, La, and Ce; The total mass fraction of the active metal phase, calculated based on metal oxides, is 10 wt% to 30 wt%.

2. The directional deep desulfurization catalyst for IGCC power generation syngas according to claim 1, characterized in that, The metal oxide of the modified alumina is one or more of zirconium oxide, zinc oxide, and titanium oxide, and the mass of the metal oxide accounts for 5 wt% to 15 wt% of the mass of the alumina. The modified alumina carrier has a specific surface area of ​​150–350 m² / g, a pore volume of 0.5–2.5 mL / g, and a pore size concentrated in the range of 2–18 nm.

3. The directional deep desulfurization catalyst for IGCC power generation syngas according to claim 2, characterized in that, The ratio of metal atoms in the main metal phase to the auxiliary metal phase is 1:1 to 4:1; The main metal phase is one or more of Ni, Mo, and Co. When the main metal phase includes Ni and Mo, the ratio of Ni to Mo metal atoms is 0.5:1 to 2.5:

1.

4. A method for preparing the IGCC power generation syngas directional deep desulfurization catalyst as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. The alumina precursor is mixed with a metal oxide modifier, and then molded, dried and calcined to obtain a modified alumina carrier. S2. The impregnation solution containing the main metal phase source and the auxiliary metal phase source is loaded onto the modified alumina support, and after pretreatment under pressure, it is calcined in a steam atmosphere and then in an air atmosphere to obtain the catalyst.

5. The preparation method of the directional deep desulfurization catalyst for IGCC power generation syngas according to claim 4, characterized in that, The aluminum oxide precursor in S1 is aluminum hydroxide dry gel; The mixing process involves ball milling aluminum hydroxide dry adhesive and metal oxide modifier separately, and then kneading them together with adhesive solvent and extrusion aid. The solvent for the adhesive is an organic acid and / or an inorganic acid; The extrusion aid is guar gum powder, and the amount of guar gum powder used is 1 to 5 wt% of the mass of the modified alumina carrier precursor.

6. The preparation method of the directional deep desulfurization catalyst for IGCC power generation syngas according to claim 5, characterized in that, The colloidal solvent in S1 is one or more of nitric acid, carbonic acid, sulfuric acid, acetic acid, and tartaric acid, and the amount used is 1wt% to 3wt% by mass. Drying temperature 70-180℃, time 2-5 hours, calcination temperature 300-600℃, time 4-8 hours.

7. The preparation method of the directional deep desulfurization catalyst for IGCC power generation syngas according to claim 4, characterized in that, The load in S2 is an equal-volume impregnation; The atmosphere for pressurized pretreatment is water vapor or ammonia, with a pretreatment temperature of 120~350℃, a time of 1~5 hours, and a pressure of 0.3~2.5MPa.

8. The preparation method of the directional deep desulfurization catalyst for IGCC power generation syngas according to claim 4, characterized in that, The main metal phase metal source in S2 is one or more of the following: water-soluble Ni source, water-soluble Mo source, and water-soluble Co source. The auxiliary metal source is one or more of the following: water-soluble Fe source, water-soluble Cu source, water-soluble La source, and water-soluble Ce source.

9. The preparation method of the directional deep desulfurization catalyst for IGCC power generation syngas according to claim 8, characterized in that, S2 is calcined in a steam atmosphere at a temperature of 250–550℃ for 4–9 hours. The air atmosphere calcination temperature is 400-600℃ and the time is 3-8 hours.

10. The application of an IGCC power generation syngas directional deep desulfurization catalyst obtained by any one of claims 1-3 or by any one of claims 4-9, characterized in that, The catalyst can be used in the deep desulfurization reaction of syngas hydrotreating in IGCC power generation technology, and can also be used in the hydrotreating desulfurization reaction of naphtha.

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