Residual oil hydrogenation catalyst as well as preparation method and application thereof

Abstract

The invention provides a residual oil hydrogenation catalyst and a preparation method and application thereof. The preparation method comprises the following steps: S1, uniformly mixing alumina powder, pseudo-boehmite powder, titanium oxide powder, a salt containing hydrogenation active metal and an auxiliary agent to obtain a dry mixture; step S2, adding an active metal salt solution and / or a peptizing agent solution into the dry mixture for mixing and kneading to obtain a wet material; s3, the wet material is subjected to extrusion molding, and wet strips are obtained; s4, sequentially drying and roasting the wet strips to obtain the residual oil hydrogenation catalyst. The roasting comprises first roasting and second roasting, the temperature of the first roasting is 900-1100 DEG C, and the temperature of the second roasting is 350-800 DEG C. The residual oil hydrogenation catalyst provided by the invention has relatively high hydrogenation activity and stability.

Description

Technical Field

[0001] This application relates to the technical field of residue hydrotreating, specifically providing a residue hydrotreating catalyst, its preparation method, and its applications. Background Technology

[0002] Residue oil, the residue after crude oil distillation, is characterized by high sulfur, high nitrogen, high metal (such as nickel and vanadium), and high carbon residue content. These complex components make the hydrotreating of residue oil challenging, requiring the use of catalysts with different properties to remove most of the metals, sulfur, nitrogen, and other impurities, and to achieve the hydroconversion of carbon residue precursors. This places high demands on the activity, selectivity, and stability of the catalysts. With increasingly stringent environmental regulations, residue oil hydrotreating catalysts need to improve light oil yield while reducing pollutant emissions; therefore, developing cost-effective catalysts is currently a key research focus.

[0003] Currently, fixed-bed residue hydrotreating remains the mainstream process for treating residue in petroleum refining. Residue hydrotreating requires the synergistic effect of multiple functional catalysts. Based on their function, fixed-bed residue hydrotreating catalysts can be categorized as protective agents, demetallizing agents, desulfurizing agents, denitrifying agents, and carbon removal agents. Catalyst loading technology and operational optimization services are also crucial for the stable operation of the unit. Depending on the feedstock properties, operating conditions, and product quality requirements, different types and properties of catalysts are typically loaded in different parts of the reactor using a gradient loading method to rationally distribute the reaction load, meet the requirements of long-term stable operation, and extend catalyst life. The basic principle of gradient loading is that along the liquid flow direction, the catalyst particle size decreases, the average pore size decreases, the porosity decreases, and the activity increases.

[0004] Patent CN115722275B discloses a method for regenerating a catalyst for hydrogenation of residual oil. This method involves mixing a regenerator and a compounding agent in a certain proportion before use. Essentially, the active metal content of the compounding agent is higher than that of the new catalyst, which is used to compensate for the loss of active metal content in the regenerator. The catalyst prepared by this method can achieve the same effect as the fresh catalyst. However, the regeneration process uses acid and water, which is lengthy and generates a large amount of acidic wastewater, resulting in significant environmental pressure.

[0005] Patent CN119368203A discloses a gradation method for a residue oil hydrotreating catalyst and its application. The hydrodesulfurization catalyst and hydrodenitrification catalyst prepared by this method use modified kaolin and molecular sieve materials mixed with boehmite, binder, extrusion aid, pore expander and other materials to obtain a support, and then load active metals by impregnation to obtain the catalyst. When used for fixed bed residue oil hydrotreating, the desulfurization rate can reach about 95% and the denitrification rate can reach more than 96%. However, the whole preparation process is lengthy and cumbersome and costly.

[0006] Patent CN113856695B discloses a method for grading a catalyst for residue oil hydrotreating and a method for treating residue oil hydrotreating. The grading method includes a hydrotreating protection catalyst, a hydrotreating demetallization catalyst, a hydrotreating desulfurization catalyst, and a hydrotreating decarbonization catalyst that are sequentially loaded along the flow direction, which can extend the operating cycle of the residue oil hydrotreating unit.

[0007] In existing reported examples, the basic approach involves loading protective agents, demetallizing agents, desulfurizing agents, decarbonizing agents, and denitrifying agents in a graded manner, with the catalyst prepared through carrier modification and metal impregnation. However, this process is lengthy and cumbersome, resulting in high production costs, low cost-effectiveness, and short catalyst lifespan. To address these issues, this invention aims to design a residue hydrotreating catalyst with a simple production process, stable activity, and long service life, and to apply it to a fixed-bed residue hydrotreating industrial unit. Summary of the Invention

[0008] In view of this, this application provides a residue oil hydrogenation catalyst, its preparation method, and its uses.

[0009] In a first aspect, this application provides a method for preparing a residue hydrotreating catalyst, the method comprising the following steps: Step S1: Mix alumina powder, boehmite powder, titanium dioxide powder, salt containing hydrogenated active metal, and additives until homogeneous to obtain a dry mixture; wherein, the alumina powder includes γ-Al2O3 micro powder, and the γ-Al2O3 micro powder includes (200-400) mesh γ-Al2O3 micro powder, (700-900) mesh γ-Al2O3 micro powder and (900-1100) mesh γ-Al2O3 micro powder, and the weight ratio of the (200-400) mesh γ-Al2O3 micro powder, the (700-900) mesh γ-Al2O3 micro powder and the (900-1100) mesh γ-Al2O3 micro powder is 1:(1.5-2):(0.8-1); Step S2: Add an active metal salt solution and / or a peptide solution to the dry mixture and knead to obtain a wet material; Step S3: The wet material is extruded to obtain a wet strip; Step S4: The wet strip is successively dried and calcined to obtain the residue oil hydrogenation catalyst; wherein, the drying temperature is (100-140)℃; the calcination includes a first calcination and a second calcination, the first calcination temperature is (900-1100)℃, and the second calcination temperature is (350-800)℃.

[0010] In some alternative embodiments, the weight ratio of the (200-400) mesh γ-Al2O3 micro powder, the (700-900) mesh γ-Al2O3 micro powder, and the (900-1100) mesh γ-Al2O3 micro powder is 1:(1.5-1.7):(0.85-0.95) (e.g., 1:(1.5-1.7):0.8, 1:(1.5-1.7):0.81, 1:(1.5-1.7):0.82, 1:(1.5-1.7):0.83, 1:(1.5-1.7):0.84, 1: (1.5~1.7):0.85, 1:(1.5~1.7):0.86, 1:(1.5~1.7):0.87, 1:(1.5~1.7):0.88, 1:(1.5~1.7):0.89, 1:(1.5~1.7):0.9, 1:(1.5~1.7):0.91, 1:(1.5~1.7):0.92, 1:(1.5~1.7):0.93, 1:(1.5~1.7):0.94, 1:(1.5~1.7):0.95, 1:1.5:(0.85~0 0.95), 1:1.51:(0.85~0.95), 1:1.52:(0.85~0.95), 1:1.53:(0.85~0.95), 1:1.54:(0.85~0.95), 1:1.55:(0.85~0.95), 1:1.56:(0.85~0.95), 1:1.57:(0.85~0.95), 1:1.58:(0.85~0.95), 1:1.59:(0.85~0.95), 1:1.6:(0.85~0.95), 1:1 .61:(0.85~0.95), 1:1.62:(0.85~0.95), 1:1.63:(0.85~0.95), 1:1.64:(0.85~0.95), 1:1.65:(0.85~0.95), 1:1.66:(0.85~0.95), 1:1.67:(0.85~0.95), 1:1.68:(0.85~0.95), 1:1.69:(0.85~0.95), 1:1.7:(0.85~0.95) or 1:1.6:0.9, etc.).

[0011] In some specific embodiments, the weight ratio of the (200-400)-target γ-Al2O3 micro powder, the (700-900)-target γ-Al2O3 micro powder, and the (900-1100)-target γ-Al2O3 micro powder is 1:1.6:0.9.

[0012] In some alternative embodiments, the γ-Al2O3 micro powder also contains other metal oxides (0-30) by weight; the other metal oxides include at least one of MoO3, NiO or CoO.

[0013] In some alternative embodiments, the average particle size of the pseudoboehmite powder is (2-4) μm (e.g., 2 μm, 3 μm or 4 μm, etc.).

[0014] In some alternative embodiments, the titanium dioxide powder is anatase TiO2 micronized powder with a particle size D50 < 0.15 μm (e.g., catalytic grade titanium dioxide).

[0015] In some alternative embodiments, the hydrogenated active metal includes Mo. 6+ Ni 2+ or Co 2+ At least one of the following. In some alternative embodiments, the salt containing a hydrogenating active metal includes at least one of molybdenum trioxide, ammonium heptamolybdate, ammonium tetramolybdate, nickel nitrate, basic nickel carbonate, cobalt nitrate, or basic cobalt carbonate. In some alternative embodiments, the salt containing a hydrogenating active metal is selected from basic carbonates containing a hydrogenating active metal. In other alternative embodiments, the salt containing a hydrogenating active metal includes at least one of basic nickel carbonate or basic cobalt carbonate. In some specific embodiments, the salt containing a hydrogenating active metal is selected from basic nickel carbonate. In other specific embodiments, the salt containing a hydrogenating active metal is selected from basic cobalt carbonate.

[0016] In some alternative embodiments, the additive includes at least one selected from guar gum powder, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, methyl hydroxypropyl cellulose, or polyacrylamide. In other alternative embodiments, the additive includes at least one selected from guar gum powder or polyacrylamide. In some specific embodiments, the additive includes guar gum powder or polyacrylamide. The weight ratio of the guar gum powder or the polyacrylamide is 1:(0.8–1.2) (e.g., 1:0.8, 1:0.9, 1:1, 1:1.1, or 1:1.2, etc.).

[0017] In some alternative embodiments, the amount of alumina powder used, by weight, is (5-20) parts (e.g., 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 parts, etc.), and the amount of pseudoboehmite powder used is (5-55) parts (e.g., 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 parts, etc.). (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, or 55 parts, etc.) of the titanium dioxide powder. The dosage is (5-20) parts (e.g., 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 parts, etc.), and the dosage of the salt containing the hydrogenated active metal is (5-30) parts (e.g., 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or 21 parts). 22, 23, 24, 25, 26, 27, 28, 29, or 30 parts, etc.), the amount of the auxiliary agent is (1 to 3) parts (e.g., 1 part, 1.5 parts, 2 parts, 2.5 parts, or 3 parts, etc.), and the total amount of the active metal salt solution and / or the colloidal solvent solution is (100 to 140) parts (e.g., 100, 102, 105, 110, 115, 120, 125, 130, 135, or 140 parts, etc.).

[0018] In some optional embodiments, the active metal salt solution comprises at least one of ammonium molybdate aqueous solution, cobalt nitrate aqueous solution, cobalt acetate aqueous solution, cobalt chloride aqueous solution, nickel nitrate aqueous solution, nickel acetate aqueous solution, or nickel sulfate aqueous solution. In some optional embodiments, the concentration of the active metal salt solution is (1.5–25) wt% (e.g., 1.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, or 25 wt%, etc.).

[0019] In some alternative embodiments, the adhesive solvent solution comprises at least one of an aqueous solution of acetic acid or an aqueous solution of nitric acid. In some alternative embodiments, the concentration of the adhesive solvent solution is (1.5–4) wt% (e.g., 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, 2.0 wt%, 2.1 wt%, 2.2 wt%, 2.3 wt%, 2.4 wt%, 2.5 wt%, 2.6 wt%, 2.7 wt%, 2.8 wt%, 2.9 wt%, 3.0 wt%, 3.1 wt%, 3.2 wt%, 3.3 wt%, 3.4 wt%, 3.5 wt%, 3.6 wt%, 3.7 wt%, 3.8 wt%, 3.9 wt%, or 4.0 wt%, etc.).

[0020] In some optional embodiments, the kneading time in step S2 is (10-60) min (e.g., 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, or 60 min, etc.). In other optional embodiments, the kneading time in step S2 is (20-40) min. In some specific embodiments, the kneading time in step S2 is 30 min.

[0021] In some alternative embodiments, in step S4, the drying temperature is (110-130)℃ (e.g., 110℃, 115℃, 120℃, 125℃, or 130℃, etc.). In some specific embodiments, in step S4, the drying temperature is 120℃.

[0022] In some alternative embodiments, the drying time in step S4 is (1-5) hours (e.g., 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, or 5 hours, etc.). In some specific embodiments, the drying time in step S4 is 2 hours.

[0023] In some optional embodiments, in step S4, the temperature of the first roasting is (950-1000)℃ (e.g., 950℃, 960℃, 970℃, 980℃, 990℃, 1000℃, etc.), and the time of the first roasting is (10-20)min (e.g., 10min, 11min, 12min, 13min, 14min, 15min, 16min, 17min, 18min, 19min, 20min, etc.); the temperature of the second roasting is (450-780)℃ (e.g., 450℃, 460℃, 470℃, 480℃, 490℃, 500℃, 510℃, 520℃, 530℃, 540℃, 550℃, 560℃, 570℃, 580℃, 590℃, 600℃, 610℃, 620℃, 630℃, 640℃, 650℃, 660℃, etc.). The temperature ranges are 670℃, 680℃, 690℃, 700℃, 710℃, 720℃, 730℃, 740℃, 750℃, 760℃, 770℃, or 780℃, etc., and the roasting time is (40~50) min (e.g., 40 min, 410 min, 42 min, 43 min, 44 min, 45 min, 46 min, 47 min, 48 min, 49 min, or 50 min, etc.).

[0024] In some alternative implementations, in step S4, the temperature of the first calcination is 980°C and the calcination time is 15 min; the temperature of the second calcination is 680°C and the calcination time is 45 min.

[0025] In a second aspect of this application, this application provides a residue oil hydrogenation catalyst prepared by the preparation method described in the first aspect of this application.

[0026] In a third aspect of this application, this application provides the use of the residue hydrotreating catalyst described in the first aspect of this application in residue hydrotreating catalysis.

[0027] This application has the following beneficial effects: First, the residual oil hydrogenation catalyst of this application has high hydrogenation activity and stability.

[0028] Secondly, this application utilizes the gradation of three particle sizes of γ-Al2O3 micro powders—(200–400) mesh, (700–900) mesh, and (900–1100) mesh—and combines this with calcination at 980°C followed by calcination at 680°C, which significantly enhances the catalytic activity of the residue oil hydrogenation catalyst. This may be because the combination of titanium dioxide and alumina can form a catalyst with a bimodal pore structure, which can provide a more suitable pore size distribution. Furthermore, this application further optimizes the bimodal pore structure of the residue hydrotreating catalyst by grading γ-Al2O3 micro powders of three particle sizes: (200-400) mesh, (700-900) mesh, and (900-1100) mesh, and by combining "calcination at 980℃ first and then at 680℃". This is beneficial to the diffusion and reaction of large molecular residue oil, helps to improve the stability and activity of the catalyst, thereby reducing the reaction temperature. Low-temperature reaction is beneficial to reducing the deposition of coke and other substances on the catalyst surface and in the pores. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the evaluation device process for this application. Detailed Implementation

[0030] This application discloses "a residue oil hydrotreating catalyst and its preparation method and uses." Those skilled in the art can refer to the content of this document and appropriately modify the process parameters to achieve the desired results. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this application. The methods and applications of this application have been described through preferred embodiments. Those skilled in the art can obviously modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit, and scope of this application to realize and apply the technology of this application.

[0031] To make the objectives, technical solutions, and advantages of this application clearer, the implementation schemes of this application will be further described in detail below with reference to the embodiments.

[0032] Examples 1-3 and Comparative Examples 1-6: The ingredient lists for Examples 1-3 and Comparative Examples 1-6 are shown in Table 1.

[0033] Table 1. Ingredients of Examples 1-3 and Comparative Examples 1-6:

[0034] Note: The average particle size of the pseudoboehmite powder is 3 μm; the titanium dioxide powder is anatase TiO2 micro powder with a particle size D50 < 0.15 μm (e.g., catalytic grade titanium dioxide).

[0035] In Examples 1-3 and Comparative Examples 1-6, the preparation method of the residue hydrotreating catalyst specifically includes the following steps: Step S1: Mix alumina powder, boehmite powder, titanium dioxide powder, salt containing hydrogenated active metal, and additives until homogeneous to obtain a dry mixture; Step S2: Add an active metal salt solution and / or a peptide solution to the dry mixture and knead for 30 minutes to obtain a wet material; Step S3: The wet material is extruded on a front-extrusion twin-screw extruder to obtain a four-leaf clover-shaped wet strip with an equivalent diameter of 1.3 mm.

[0036] Step S4: The wet strip is successively dried and calcined to obtain the residue oil hydrogenation catalyst.

[0037] (1) Radial compressive strength test: The radial compressive strength of the residue hydrotreating catalyst was tested according to ASTM D6179-2020 standard.

[0038] (2) Detection of water pore volume: The water pore volume of the residue hydrogenation catalyst was detected in accordance with HG / T 5594-2019 "Determination of Pore Structure of Petroleum Refining Catalyst".

[0039] Table 2. Physical property test results of Examples 1-3 and Comparative Examples 1-6:

[0040] Catalytic performance testing of residue hydrotreating catalysts: The feedstock is a residue oil feedstock from a domestic refinery. The properties of the feedstock are shown in Table 3.

[0041] Table 3. Properties of the feedstock oil:

[0042] The experiment was conducted on the 300ml fixed-bed residue hydrotreating unit of Haishunde Company, following the existing operating procedures of industrial facilities. A schematic diagram of the evaluation unit's process is attached. Figure 1 .

[0043] The residue hydrotreating catalysts of Examples 1-3 and Comparative Examples 1-6 were respectively packed into R320 / R350 reactors, with a total catalyst loading of 300 ml. The evaluation process conditions are shown in Table 4. After 1 hour of operation and 8000 hours of operation, the catalytic performance evaluation results of the residue hydrotreating catalysts in Examples 1-3 and Comparative Examples 1-6 are shown in Table 5.

[0044] Table 4. Evaluation Criteria:

[0045] Table 5. Evaluation results of catalytic performance of residue hydrotreating catalysts:

[0046] As can be seen from Table 5, the residue hydrotreating catalyst of this application has high catalytic activity and stability.

[0047] By comparing Example 1 and Comparative Examples 1-3, it can be seen that the present application can significantly improve the catalytic activity of the residue oil hydrogenation catalyst by grading γ-Al2O3 micro powders with three particle sizes: (200-400) mesh, (700-900) mesh, and (900-1100) mesh.

[0048] By comparing Example 1 and Comparative Examples 4-6, it can be seen that the "calcination at 980°C first and then at 680°C" in this application can significantly improve the catalytic activity of the residue hydrogenation catalyst.

[0049] This may be because the combination of titanium dioxide and alumina can form a catalyst with a bimodal pore structure, which can provide a more suitable pore size distribution. Furthermore, this application further optimizes the bimodal pore structure of the residue hydrotreating catalyst by grading γ-Al2O3 micro powders of three particle sizes: (200-400) mesh, (700-900) mesh, and (900-1100) mesh, and by combining "calcination at 980℃ first and then at 680℃". This is beneficial to the diffusion and reaction of large molecular residue oil, helps to improve the stability and activity of the catalyst, thereby reducing the reaction temperature. Low-temperature reaction is beneficial to reducing the deposition of coke and other substances on the catalyst surface and in the pores.

[0050] The foregoing has provided a detailed description of the "residue oil hydrogenation catalyst, its preparation method, and its uses" provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are merely for the purpose of helping to understand the method and core ideas of this application. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A process for preparing a residue hydroprocessing catalyst, characterized by, The preparation method comprises the following steps: Step S1, mixing alumina powder, pseudo-boehmite powder, titanium oxide powder, a salt containing a hydrogenation active metal, and an additive to be uniform to obtain a dry mixture; wherein the alumina powder comprises γ-Al2O3 micro powder, the γ-Al2O3 micro powder comprises (200-400) mesh γ-Al2O3 micro powder, (700-900) mesh γ-Al2O3 micro powder, and (900-1100) mesh γ-Al2O3 micro powder, and the weight ratio of the (200-400) mesh γ-Al2O3 micro powder, the (700-900) mesh γ-Al2O3 micro powder, and the (900-1100) mesh γ-Al2O3 micro powder is 1:(1.5-2):(0.8-1); Step S2, adding an active metal salt solution and / or a peptizing agent solution to the dry mixture to knead to obtain a wet material; Step S3, the wet material is extruded to obtain a wet strip; Step S4, the wet strip is sequentially dried and calcined to obtain the residual oil hydrogenation catalyst; wherein the drying temperature is (100-140) °C; the calcining comprises first calcining and second calcining, the temperature of the first calcining is (900-1100) °C, and the temperature of the second calcining is (350-800) °C.

2. The production method according to claim 1, characterized by, The weight ratio of the (200-400) mesh γ-Al2O3 micro powder, the (700-900) mesh γ-Al2O3 micro powder, and the (900-1100) mesh γ-Al2O3 micro powder is 1:1.6:0.

9.

3. The production method according to claim 2, characterized by, The weight ratio of the (200-400) mesh γ-Al2O3 micro powder, the (700-900) mesh γ-Al2O3 micro powder, and the (900-1100) mesh γ-Al2O3 micro powder is 1:1.6:0.

9.

4. The method of claim 1, wherein, In step S4, the temperature of the first calcining is (950-1000) °C, and the time of the first calcining is (10-20) min; the temperature of the second calcining is (450-780) °C, and the time of the calcining is (40-50) min.

5. The preparation method according to claim 4, characterized in that, In step S4, the temperature of the first calcining is 980 °C, and the time of the first calcining is 15 min; the temperature of the second calcining is 680 °C, and the time of the calcining is 45 min.

6. The method of claim 1, wherein, The salt containing a hydrogenation active metal comprises at least one of molybdenum trioxide, ammonium heptamolybdate, ammonium tetramolybdate, nickel nitrate, basic nickel carbonate, cobalt nitrate, or basic cobalt carbonate.

7. The preparation method according to claim 1, characterized in that, The additive comprises at least one of sesbania powder, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, methylhydroxypropyl cellulose, or polyacrylamide; And / or, the γ-Al2O3 micro powder further contains other metal oxides (0-30) % by weight; the other metal oxides comprise at least one of MoO3, NiO, or CoO.

8. The production method according to any one of claims 1 to 7, characterized by, The amount of the alumina powder is (5-20) parts, the amount of the pseudoboehmite powder is (5-55) parts, the amount of the titanium oxide powder is (5-20) parts, the amount of the salt containing hydrogenation active metal is (5-30) parts, the amount of the auxiliary is (1-3) parts, and the total amount of the active metal salt solution and / or the peptizing agent solution is (100-140) parts, all by weight.

9. The residue hydroprocessing catalyst prepared according to the preparation method of any one of claims 1 to 8.

10. Use of the residue hydroprocessing catalyst of claim 9 in residue hydroprocessing.

Images