CN106582694A - Method for preparing ternary metal non-supported nickel-based catalyst by adding auxiliaries - Google Patents

Abstract

The invention relates to a preparation method of a ternary metal non-supported nickel-based catalyst with additives. The auxiliary agent is introduced in the preparation process of the non-supported catalyst, and the active component and the auxiliary agent are combined, that is, in molybdic acid Polyethylene glycol (PEG) of different molecular weights is added to the mixed solution of nickel and ammonium metatungstate as a dispersant (the molecular weight of PEG is between 100-10000). The non-supported catalyst preparation process of the present invention can improve the hydrogenation performance of the catalyst and the dispersibility of active metals, significantly improve the desulfurization rate of middle distillate oil or heavy distillate oil, and achieve the effect of deep desulfurization.

Description

A kind of preparation method of ternary metal non-supported nickel-based catalyst with additive

technical field

The invention belongs to the field of hydrogenation refining in industrial catalysis, and in particular relates to a preparation method of a ternary metal non-supported nickel-based catalyst with additives added. Specifically, the present invention is particularly suitable for the preparation of a deep hydrodesulfurization catalyst for middle distillate oil or heavy distillate oil.

Background technique

After frequent smog troubles in recent years, automobile exhaust has become "the target of public criticism", and the upgrading of oil quality is still a topic of focus in recent years. Some cities in my country have begun to implement the National V emission standard on July 1, 2015. In 2016 my country will fully implement the National V emission standards.

Hydrodesulfurization catalysts have been used in catalytic diesel upgrading for decades. At present, there are two main types of hydrodesulfurization catalysts: one is a supported catalyst, the other is a non-supported catalyst; Industrial catalysts need to meet the following conditions: large enough specific surface area and pore volume, suitable pore distribution and surface acidity, uniform dispersion of active components and other factors. At present, supported catalysts are widely used in industry, and the synthesis method is often that the active components are supported on γ-Al ₂ O ₃ or molecular sieves, and then dried, roasted, shaped and other steps to obtain supported catalysts. In CN104,248,965A, the active metal component is impregnated on the self-made high specific surface macroporous alumina carrier to prepare a highly active hydrodesulfurization catalyst. In addition, due to the increasing perfection of hydrodesulfurization catalytic theory and the progress of preparation technology, the catalytic activity of supported catalysts is also continuously improving. Therefore, in recent years, attention to non-supported hydrodesulfurization catalysts has increased. In CN103,801,316B, a composite oxide precursor was prepared by co-precipitation method, impregnated with a specific impregnating solution containing Co and Mo, dried and roasted A hydrodesulfurization catalyst is obtained. US6534437 and US6652738 introduced a method for preparing a non-supported catalyst, using a hydrothermal synthesis method to obtain a mixed metal composite oxide and prepare a hydrogenation catalyst.

However, the existing non-supported catalyst preparation technology has disadvantages such as poor dispersion of catalyst metal active components, underdeveloped pore structure, and weak mechanical strength.

Contents of the invention

The purpose of the invention is to improve the disadvantages of the existing non-supported catalyst preparation technology, such as poor dispersion of catalyst metal active components, underdeveloped pore structure, weak mechanical strength and the like. Increase the metal utilization rate of the catalyst and improve its hydrogenation reaction activity. Its specific preparation scheme is as follows:

Two kinds of VIB group metal compounds are selected as the active component materials, dissolved in a certain amount of deionized water to form solution A, and the solution A is adjusted to an appropriate pH value with a precipitant; nickel salt with certain water solubility is selected as the catalytic group Divide raw materials, dissolve in a certain amount of deionized water to make solution B; add solution B to solution A, it can be seen that a precipitate is formed; stir the suspension containing precipitate at 60-90 ℃, add additives during the stirring process, so that the active group After the separation and compounding are completed, the solution is allowed to stand at a constant temperature after the stirring is completed, and it is subjected to aging treatment for 2-16 hours; after the aging process is completed, the suspension is filtered with suction, and the filter cake is washed with deionized water, and the filter cake is placed in a constant temperature infrared drying oven Dry for 4-32 hours to obtain a catalyst precursor; after roasting and reduction in a vessel, a non-supported catalyst with good hydrodesulfurization activity can be obtained.

The selected water-soluble nickel salt is one of nickel nitrate, nickel acetate, nickel chloride and nickel sulfate, and the two VIB group metal compounds are ammonium salts of Mo and W.

The metal molar ratio of the catalytic promoter component Ni to the two VIB group active components is 1:1:1-4:1:1.

Solution A has a pH range of 8-11.

The precipitating agent is one of ammonia water, sodium carbonate, sodium bicarbonate and sodium hydroxide.

The method of adding solution B to solution A is to add dropwise or all at once; when adding dropwise, use same temperature or different temperature dropwise addition.

The aging time is preferably 6-10 h.

The catalyst precursor is roasted at a temperature of 300-500 °C, and the roasting time is 2-6 hours. After the roasting is completed, the corresponding catalyst in the oxidation state is obtained; the catalyst in the oxidation state is subjected to sulfuration and reduction in the vessel, and the reduction pressure is 2-4MPa , the temperature is 200-400 ℃, the space velocity is 1-4 h ^-1 , the volume ratio of hydrogen to oil is 200-700, the reduction time is 4-24 h, and the corresponding sulfided catalyst is obtained after the reduction process.

The auxiliary agent is polyethylene glycol (PEG), wherein the molecular weight of PEG is between 100-20000.

The stirring temperature is preferably 80-90°C, and the stirring time is 3-8 h.

The advantages and effects of the present invention are as follows:

The specific surface area of the non-supported ternary metal catalyst prepared by the invention is 70-120 m ² /g, the pore volume is 0.15-0.19 cm ³ /g, and the average pore diameter is 5.6-6.7 nm. The catalyst particle size is fine, the metal utilization rate is high, and the hydrodesulfurization reaction activity is good. The Ni-based non-supported catalyst prepared by adding auxiliary agents in the preparation process of the present invention has a large specific surface area, developed pore structure, and can provide abundant hydrodesulfurization active sites. Therefore, the non-supported catalyst prepared by the invention has higher hydrodesulfurization activity than the traditional supported catalyst. Moreover, the present invention has mild operating conditions, low cost and low energy consumption, and is suitable for industrial scale-up production.

The non-loaded Ni-based catalyst prepared by the invention is used for hydrodesulfurization reaction of middle distillate oil or heavy distillate oil, and improves the removal rate of sulfide in middle distillate oil or heavy distillate oil. Through catalytic hydrogenation reaction, the sulfide molecules in middle distillate oil or heavy distillate oil can be converted into hydrogen sulfide to the greatest extent, and the desulfurization rate of middle distillate oil or heavy distillate oil can be significantly improved to meet the increasingly stringent requirements for middle distillate oil or heavy distillate oil. National standard for oil sulfur content.

Description of drawings

Figure 1 is a schematic diagram of the surface morphology of the catalyst.

detailed description

The present invention will be described in depth below in conjunction with examples.

Example 1

According to the metal molar ratio of Ni:Mo:W=2:1:1, 9.954 g of nickel acetate tetrahydrate, 5.071 g of ammonium heptamolybdate, and 3.531 g of ammonium metatungstate were weighed. Pour 5.071 g of ammonium heptamolybdate and 3.531 g of ammonium metatungstate into a three-necked flask with a capacity of 500 ml, and dissolve them completely with 300 ml of deionized water at 50 °C to obtain solution A. Use ammonia water as the precipitant to adjust the pH of solution A to 9, and heat the temperature of solution A to 90 °C in a water bath. Pour 9.954 g of nickel acetate tetrahydrate into a beaker and dissolve in 20 ml of deionized water to obtain solution B. At the same temperature, slowly change solution B and drop it into solution A, and it can be seen that a precipitate is gradually formed. After the dropwise addition, the solution was stirred at 90°C for 5 h to fully compound the active components. During the stirring process, 1.856 g of polyethylene glycol C was added to the solution. After the stirring was completed, the suspension was allowed to stand for hydrothermal aging treatment, and the aging time was 2 h. After aging, the suspension was filtered with suction, and the filter cake was washed. The filter cake was placed in an infrared drying oven and dried at 110 °C for 12 h to prepare the catalyst precursor. The precursor was calcined at 450 °C for 4 h to obtain the oxidized catalyst. The calcined catalyst is pressed into tablets and sieved, and 20-40 mesh particles are selected and loaded into the reactor. Under the conditions of 4 MPa, 360 ℃, 2 h ^-1 , and G/L=500, the catalyst was subjected to in-vessel sulfide reduction. The specific surface area of the obtained catalyst was 79 m ² /g, the pore volume was 0.14 cm ³ /g, and the average pore diameter was 5.5 nm.

Example 2

According to the metal molar ratio of Ni:Mo:W=2:1:1, 11.632 g of nickel nitrate hexahydrate, 5.071 g of ammonium heptamolybdate, and 3.531 g of ammonium metatungstate were weighed. Pour the Mo and W compounds into a three-neck flask with a capacity of 500 ml, and completely dissolve them with 300 ml of deionized water at 50°C to obtain solution A. Use ammonia water as the precipitant to adjust the pH of solution A to 9, and heat the temperature of solution A to 90 °C in a water bath. Pour nickel nitrate hexahydrate into a beaker and dissolve in 20 ml deionized water to obtain solution B. At the same temperature, slowly change solution B and drop it into solution A, and it can be seen that a precipitate is gradually formed. After the dropwise addition, the solution was stirred at 90 °C for 5 h to fully compound the active components. During the stirring process, 2.023 g of polyethylene glycol C was added to the solution. After the stirring was completed, the suspension was allowed to stand for hydrothermal aging treatment, and the aging time was 2 h. After aging, the suspension was filtered with suction, and the filter cake was washed. The filter cake was placed in an infrared drying oven and dried at 110 °C for 12 h to prepare the catalyst precursor. The precursor was calcined at 450 °C for 4 h to obtain the oxidized catalyst. The calcined catalyst is pressed into tablets and sieved, and 20-40 mesh particles are selected and loaded into the reactor. Under the conditions of 4 MPa, 360 ℃, 2 h ^-1 , and G/L=500, the catalyst was subjected to in-vessel sulfide reduction. The specific surface area of the obtained catalyst was 86 m ² /g, the pore volume was 0.15 cm ³ /g, and the average pore diameter was 5.8 nm.

Example 3

According to the metal molar ratio of Ni:Mo:W=2:1:1, 9.520 g of nickel chloride hexahydrate, 5.071 g of ammonium heptamolybdate, and 3.531 g of ammonium metatungstate were weighed. Pour the Mo and W compounds into a three-neck flask with a capacity of 500 ml, and dissolve them completely with 300 ml of deionized water at 50 °C to obtain solution A. Use ammonia water as the precipitant to adjust the pH of solution A to 9, and heat the temperature of solution A to 90°C in a water bath. Pour nickel chloride hexahydrate into a beaker and dissolve in 20 ml deionized water to obtain solution B. At the same temperature, slowly change solution B and drop it into solution A, and it can be seen that a precipitate is gradually formed. After the dropwise addition, the solution was stirred at 90 °C for 5 h to fully compound the active components. During the stirring process, 1.812 g of polyethylene glycol C was added to the solution. After the stirring was completed, the suspension was left to stand for hydrothermal aging treatment, and the aging time was 2 h. After aging, the suspension was filtered with suction, and the filter cake was washed. The filter cake was placed in an infrared drying oven and dried at 110 °C for 12 h to prepare the catalyst precursor. The precursor was calcined at 450 °C for 4 h to obtain the oxidized catalyst. The calcined catalyst is pressed into tablets and sieved, and 20-40 mesh particles are selected and loaded into the reactor. Under the conditions of 4 MPa, 360 ℃, 2 h ^-1 , and G/L=500, the catalyst was subjected to in-vessel sulfide reduction. The specific surface area of the obtained catalyst was 95 m ² /g, the pore volume was 0.15 cm ³ /g, and the average pore diameter was 6.0 nm.

Example 4

According to the metal molar ratio of Ni:Mo:W=2:1:1, 9.520 g of nickel chloride hexahydrate, 5.071 g of ammonium heptamolybdate, and 3.531 g of ammonium metatungstate were weighed. Pour the Mo and W compounds into a three-neck flask with a capacity of 500 ml, and dissolve them completely with 300 ml of deionized water at 50 °C to obtain solution A. Use ammonia water as the precipitant to adjust the pH of solution A to 9, and heat the temperature of solution A to 90°C in a water bath. Pour nickel chloride hexahydrate into a beaker and dissolve in 20 ml deionized water to obtain solution B. At the same temperature, slowly change solution B and drop it into solution A, and it can be seen that a precipitate is gradually formed. After the dropwise addition, the solution was stirred at 90 °C for 5 h to fully compound the active components. During the stirring process, 1.812 g of polyethylene glycol C was added to the solution. After the stirring was completed, the suspension was allowed to stand for hydrothermal aging treatment, and the aging time was 4 h. After aging, the suspension was filtered with suction, and the filter cake was washed. The filter cake was placed in an infrared drying oven and dried at 110 °C for 12 h to prepare the catalyst precursor. The precursor was calcined at 450 °C for 4 h to obtain the oxidized catalyst. The calcined catalyst is pressed into tablets and sieved, and 20-40 mesh particles are selected and loaded into the reactor. Under the conditions of 4 MPa, 360 ℃, 2 h ^-1 , and G/L=500, the catalyst was subjected to in-vessel sulfide reduction. The specific surface area of the obtained catalyst was 108 m ² /g, the pore volume was 0.17 cm ³ /g, and the average pore diameter was 6.4 nm.

Example 5

This example illustrates the preparation of a comparative catalyst.

According to the metal molar ratio of Ni:Mo:W=2:1:1, 9.954 g of nickel acetate tetrahydrate, 5.071 g of ammonium heptamolybdate, and 3.531 g of ammonium metatungstate were weighed. Pour the Mo and W compounds into a three-neck flask with a capacity of 500 ml, and completely dissolve them with 300 ml of deionized water at 50°C to obtain solution A. Use ammonia water as the precipitant to adjust the pH of solution A to 9, and heat the temperature of solution A to 90 °C in a water bath. Pour nickel acetate tetrahydrate into a beaker and dissolve with an appropriate amount of deionized water to obtain solution B. At the same temperature, slowly change solution B and drop it into solution A, and it can be seen that a precipitate is gradually formed. During the stirring process, 1.856 g of polyethylene glycol C was added to the solution, and after the dropwise addition was completed, the solution was stirred at 90 °C for 5 h to fully compound the active components. After the stirring was completed, the suspension was filtered with suction, and the filter cake was washed. The filter cake was placed in an infrared drying oven and dried at 110 °C for 12 h to prepare the catalyst precursor. The precursor was calcined at 450 °C for 4 h to obtain the oxidized catalyst. The calcined catalyst is pressed into tablets and sieved, and 20-40 mesh particles are selected and loaded into the reactor. Under the conditions of 4 MPa, 360 ℃, 2 h ^-1 , and G/L=500, the catalyst was subjected to in-vessel sulfide reduction. The specific surface area of the obtained catalyst was 72 m ² /g, the pore volume was 0.13 cm ³ /g, and the average pore diameter was 5.2 nm.

Example 6

This example illustrates the evaluation method of the catalyst of the present invention

The activity evaluation of the catalyst was carried out on a 10 ml high-pressure micro-hydrogenation reactor. The evaluation raw material is Tianjin Petrochemical catalytic cracking middle distillate oil or heavy distillate oil. The raw material is pumped in by a gear pump. After the product is gas-liquid separated by the cold high fraction and low pressure separator, the liquid product is connected to the collection tank. After the pre-vulcanization process was completed, the temperature was lowered to 280 °C, and the evaluation raw materials were pumped in. Samples were collected 6 h after the reaction was stable, and samples were collected every 3 h. The surface morphology of the catalyst is shown in Figure 1, and the activity evaluation results of the catalyst are shown in Table 1.

Example 7

The metal molar ratio of the catalytic promoter component Ni to the two VIB group active components is 1:1:1. Solution A has a pH of 8. Described precipitation agent is sodium bicarbonate. The method of adding solution B to solution A is one-time addition; the aging time is preferably 6 h. The catalyst precursor was calcined at a temperature of 300 °C and the roasting time was 2 h, and the corresponding oxidized catalyst was obtained after the calcination; the oxidized catalyst was subjected to in-vessel sulfidation reduction at a reduction pressure of 2 MPa and a temperature of 200 °C , the space velocity is 1h ^-1 , the volume ratio of hydrogen to oil is 200:1, and the reduction time is 4h. After the reduction process, the corresponding sulfided catalyst is obtained. The auxiliary agent is polyethylene glycol (PEG), wherein the molecular weight of PEG is between 100-20000. said

The stirring temperature is preferably 80°C, and the stirring time is 3h. Other steps are the same as in Example 1.

Example 8

The molar ratio of the catalyst-promoting component Ni to the two VIB group active components is 4:1:1. Solution A has a pH of 11.

Described precipitation agent is sodium hydroxide. Solution B is added to solution A dropwise at the same temperature; the aging time is preferably 10 h. The catalyst precursor was calcined at a temperature of 500 °C and the roasting time was 6 h. After the roasting, the corresponding oxidized catalyst was obtained; the oxidized catalyst was subjected to in-vehicle sulfidation reduction with a reduction pressure of 4 MPa and a temperature of 400 °C. The space velocity was 4 h ^-1 , the volume ratio of hydrogen to oil was 700:1, and the reduction time was 24 h. After the reduction process, the corresponding sulfided catalyst was obtained. The auxiliary agent is polyethylene glycol (PEG), wherein the molecular weight of PEG is between 100-20000.

The stirring temperature is preferably 90 °C, and the stirring time is 8 h. Other steps are the same as in Example 1.

Example 9

The suspension containing the precipitate was stirred at 60° C., aged for 16 h; the filter cake was dried in a constant temperature infrared drying oven for 32 h, and the other steps were the same as in Example 1.

Invention effect:

Compared with the existing conventional non-supported catalyst preparation technology, the obvious technical feature of the present invention is the selection of a suitable water-soluble nickel source in the process of preparing the non-supported catalyst by the co-precipitation method, and the introduction of the additive polyethylene glycol. This makes the fineness of the prepared non-supported catalyst particles higher, the pore structure more developed, the metal utilization rate correspondingly increased, and the hydrodesulfurization activity significantly improved. At the same time, the invention has simple operation, mild preparation conditions, and is suitable for batch production and industrial application.

Table 1 Evaluation results of the hydrodesulfurization activity of the catalyst of the present invention

catalyst C1 C2 C3 C4 C5 HDS% 97.1 97.3 97.9 98.7 95.6

Claims (10)

1. a preparation method of a ternary metal non-supported nickel-based catalyst adding an auxiliary agent is characterized in that it may further comprise the steps: Two kinds of VIB group metal compounds are selected as the active component materials, dissolved in a certain amount of deionized water to form solution A, and the solution A is adjusted to an appropriate pH value with a precipitant; nickel salt with certain water solubility is selected as the catalytic group Divide raw materials, dissolve in a certain amount of deionized water to make solution B; add solution B to solution A, it can be seen that a precipitate is formed; stir the suspension containing precipitate at 60-90 ℃, add additives during the stirring process, so that the active group After the separation and compounding are completed, the solution is allowed to stand at a constant temperature after the stirring is completed, and it is subjected to aging treatment for 2-16 hours; after the aging process is completed, the suspension is filtered with suction, and the filter cake is washed with deionized water, and the filter cake is placed in a constant temperature infrared drying oven Dry for 4-32 hours to obtain a catalyst precursor; after roasting and reduction in a vessel, a non-supported catalyst with good hydrodesulfurization activity can be obtained. 2. preparation method according to claim 1 is characterized in that, the selected water-soluble nickel salt is the one in nickel nitrate, nickel acetate, nickel chloride, nickel sulfate, and two kinds of VIB group metal compounds are Mo, Ammonium salt of W. 3. The preparation method according to claim 1, characterized in that the metal molar ratio of the catalytic promoter component Ni and the two VIB group active components is 1:1:1-4:1:1. 4. The preparation method according to claim 1, characterized in that the pH range of solution A is 8-11. 5. preparation method according to claim 1, is characterized in that, described precipitation agent is the one in ammoniacal liquor, sodium carbonate, sodium bicarbonate and sodium hydroxide. 6. The preparation method according to claim 1, characterized in that, the method of adding solution B to solution A is dropwise addition or one-time addition; when adding dropwise, it is added dropwise at the same temperature or at different temperatures. 7. The preparation method according to claim 1, characterized in that, the aging time is preferably 6-10 h. 8. The preparation method according to claim 1, characterized in that the catalyst precursor can be roasted, the roasting temperature is 300-500 ° C, the roasting time is 2-6 h, and the corresponding oxidation state catalyst is obtained after roasting ; In-vehicle sulfidation reduction is carried out on the oxidized catalyst, the reduction pressure is 2-4 MPa, the temperature is 200-400 ℃, the space velocity is 1-4 h ^-1 , the volume ratio of hydrogen to oil is 200-700:1, and the reduction time is After 4-24 h, the corresponding sulfided catalyst was obtained after the reduction process. 9. The preparation method according to claim 1, characterized in that, the auxiliary agent is polyethylene glycol (PEG), wherein the molecular weight of PEG is between 100-20000. 10. The preparation method according to claim 1, characterized in that, the stirring temperature is preferably 80-90°C, and the stirring time is 3-8 h.