CN102513113B - A slurry catalyst for producing ethanol from slurry bed synthesis gas and preparation method thereof - Google Patents

Abstract

The invention provides a slurry catalyst for preparing ethanol from synthesis gas in slurry bed, which is an M-Cu/ZnO/Al2O3 catalyst, wherein M and Cu are active components, ZnO is a structure promoter and Al2O3 is a carrier; the molar ratio of the contents of the components of the catalyst is as follows: Cu/Zn/Al=2.0/(0.8-1.0)/(0.4-0.8), and M is 0.01-0.02%. The method comprises the following steps of: preparing aluminum sol and hydrolyzing aluminum salt at a temperature more than 80 DEG C; adding peptizing agent to adjust the pH value to 3-4 and obtain sol; dissolving soluble Cu and Zn salts to obtain an aqueous solution or an alcoholic solution; slowly adding the solutions into the sol; and then, adding the dissolved M compound into the sol, reflowing and uniformly agitating at 95 DEG C, and ageing to form gel; and then directly dispersing the gel in a slurry reactor reaction solvent; uniformly agitating and carrying out heat treatment; and after the Cu, Zn and Fe salts are decomposed, reducing to prepare the slurry catalyst. The catalyst provided by the invention has the advantages of higher ethanol selectivity, low cost, and good stability, dispersity and liquidity.

Description

A slurry catalyst for producing ethanol from slurry bed synthesis gas and preparation method thereof

technical field

The invention relates to a catalyst for synthesizing ethanol in a slurry bed and a preparation method thereof, specifically, a slurry catalyst for synthesizing ethanol with synthesis gas in a slurry bed and a preparation method thereof.

Background technique

In the prior art, the catalyst for synthesizing ethanol from synthesis gas is mainly a Rh-based catalyst, and its representative composition and content are 2.5 _wt % Rh, 0.05 _wt % Fe loaded on SiO ₂ from Union Carbide Company; Rh:Th:Co(1:1 :0.1) load on SiO ₂ ; Rh (1): Th (1): M (0.00614 when M=Li, when M=In or Cd is 0.05) load and SiO ₂ ; Chinese Academy of Sciences 2009 patent application composition: Rh _wt 1-10% loaded on regular hexagonal molecular sieves; Dalian Institute of Chemical Physics patent: 0.01-10 _wt % Rh loaded on high silicon-aluminum ratio molecular sieves; others include 1% RhCoFeK/SiO ₂ , 1% Rh/V ₂ O ₅ , 1%Rh/ZrO ₂ , 6%Rh1.5%Mn/SiO _{2 ,} etc.; this catalyst has a good selectivity to ethanol, which can be as high as more than 50%, and it can reach 68.9% as reported by Dalian Chemical Industry Institute, but rhodium resources are few , the price is expensive, which limits the large-scale use; other related to syngas synthesis of ethanol is synthesis gas synthesis of low-carbon alcohol catalyst: Mo-based catalyst, its representative composition and content Dow Chemical company patent: MoS ₂ 0.1-0.5%K/SiO ₂ ; similar to 1%KCo1Mo4, 1%KNiMo2C (K/Mo=0.2), 0.1-0.5%K1%RhMoS ₂ /Al ₂ O ₃ , KCoMoS ₂ /C (Mo/Co=1,4,16) , K ₂ CO ₃ CoMoS ₂ ; modified methanol catalyst, the representative composition and content of the catalyst are patented by Sud Chemie Company: 25-40 _wt %CuO, 10-18 wt% Al ₂ O ₃ , 30-45 _wt %ZnO, 1.7 -2.5%wt%K ₂ O; 3 _mol %CsCu1ZnO1Cr ₂ O ₃ 0.8, 3 _wt %K5.9 _wt %PbZnO1Cr ₂ O ₃ 0.8, 3 _mol %CsZnO1Cr ₂ O ₃ 0.8, etc.; modified FT synthesis catalyst, the catalyst The representative composition and content are IFP company patents: CuCoM0.8A0.09 (M=Cr, Fe, V, Mn; A=alkali metal), others include CoReSr/SiO ₂ , Fe/Al ₂ O ₃ , CoIrSr/SiO ₂ , CoRuSr/SiO ₂ and so on. The ethanol selectivity of the above-mentioned catalysts needs to be improved. Among them, the selectivity of the modified FT synthesis catalyst and the Mo-based catalyst can be as high as 35%, and the ethanol selectivity of the modified methanol catalyst is less than 10%. It is worth mentioning that if the modified methanol catalyst can improve the ethanol selectivity, it is the most cost-competitive and has the most industrialization prospect.

In the prior art, the slurry bed has good thermal dispersion and is more suitable for the exothermic reaction of synthesis gas to ethanol than the fixed bed; at present, the catalyst preparation methods of the slurry bed mainly use co-precipitation method and impregnation method. The precipitation method is to adjust the pH of the soluble metal (nitrate) salt with alkali or acid until the salt is precipitated together, and then calcined at a high temperature to obtain a solid catalyst, which is dispersed into a slurry bed solvent after molding; such as Cs-Cu/ZnO/Al ₂ O ₃ catalyst, use soda ash at 60-70°C to adjust the pH to about 6.8-7.0, so that copper nitrate, zinc nitrate and aluminum nitrate are all precipitated, and the mixed sodium ions are washed and dried at 100°C, and then brought in with N ₂ Quantitative CsOOCH solution is calcined at 350°C-400°C for 4 hours, and finally reduced with 2% H ₂ /N ₂ at 250°C-300°C. The impregnation method is to impregnate the salt solution on a solid carrier such as SiO ₂ , and then calcine it at high temperature and disperse it into a slurry bed solvent. For example, the auxiliary agent-type Rh catalyst is prepared by isovolumic impregnation method: impregnate silica gel with a given amount of Rh(NO ₃ ) ₃ ·2H ₂ O and nitrate mixed methanol solution of Fe, etc., then remove the solvent at room temperature, and After drying for 1 hour, H ₂ (1000h ^-1 ) was finally passed through, and the temperature was raised to 400°C for 8 hours for reduction. The impregnation method fails to ensure that all the active components and additives used are loaded on the carrier, and the weak adhesion may also be washed off with the extract when the solvent is extracted at room temperature, and the measurement accuracy is poor. The solid catalyst prepared by the above-mentioned traditional method is dispersed in the slurry bed solvent, and the uniformity, fluidity and stability of the catalyst are relatively poor. The experimental results are shown in Figure 1.

Contents of the invention

The technical problem to be solved by the present invention is to improve the selectivity of the catalyst active material for ethanol production from syngas in a slurry bed to ethanol and the uniformity, fluidity and stability of the catalyst in the slurry bed, reduce the cost of the catalyst, and provide a The invention discloses a slurry catalyst for preparing ethanol from a slurry bed synthesis gas and a preparation method thereof.

The measure that the present invention adopts is a kind of slurry catalyst of slurry bed syngas to ethanol and the technical scheme of the preparation method of slurry catalyst thereof:

A slurry catalyst for producing ethanol from slurry bed synthesis gas, the catalyst is a M-Cu/ZnO/Al ₂ O ₃ catalyst, wherein M and Cu are active components, ZnO is a structural aid, and Al ₂ O ₃ is a carrier, its composition and content are Cu:Zn:Al=2.0: (0.8-1.0): (0.4-0.8) according to the atomic ratio, and M is 0.01-0.02%. Wherein, M is one or a mixture of soluble iron salts, cobalt salts and nickel salts or soluble salts converted from other compounds.

A preparation method of a slurry catalyst for producing ethanol from a slurry bed synthesis gas, the method is to first hydrolyze an aluminum salt in water above 80°C, add a peptizer to adjust the pH to 3-4 to make an aluminum sol, and then Soluble Cu salt and Zn salt are dissolved to form a water or alcohol solution, slowly added to the sol, and then the water or alcohol solution of the M compound is added to the above sol, refluxed and stirred evenly above 95°C, aged to form a gel; then the gel Directly disperse in the solvent of the slurry bed reaction, stir evenly for heat treatment, after the decomposition of Cu salt, Zn salt and M compound is completed, it is reduced by dilute hydrogen or synthesis gas to obtain the slurry catalyst and gel intermediate and the catalyst after heat treatment are shown in Fig. 2.

Implement the slurry catalyst and preparation method thereof of a kind of slurry bed synthesis gas ethanol system provided by the present invention, compared with prior art, the prepared M-Cu/ZnO/ _Al2O3 catalyst of _the present invention, at first is The application in the slurry bed greatly improves the selectivity of the Cu/ZnO/Al ₂ O ₃ catalyst to ethanol, and the experimental results reach more than 35%; the highest reaches 54.5%. Reduced the preparation cost of catalyst; the 3rd is that the catalyst prepared by the present invention has good stability, dispersibility and fluidity in the slurry bed, in experiment, the slurry catalyst does not appear delamination phenomenon, reacts 100 hours without deactivation The signs and experimental results are shown in Figure 3.

Description of drawings

Fig. 1 is a comparison diagram of dispersion experiment effects of the present invention. In the figure: the left side is the state of the catalyst of the present invention after standing for 72 hours, the catalyst is evenly dispersed without delamination; the right side is the state of the traditional solid catalyst dispersed in the solvent and standing for 30 minutes, obviously the solid catalyst is in the beaker bottom layer;

Figure 2 is a diagram of the preparation process of the catalyst of the present invention. In the figure: the right side is the gel before heat treatment in the catalyst production process, and the left side is the unreduced slurry catalyst after heat treatment;

Fig. 3 is the comparison chart of the performance evaluation of the catalyst of the present invention in the preparation of ethanol in a slurry bed;

Fig. 4 is a comparison chart of the performance evaluation of the existing catalysts for producing ethanol in a slurry bed. the

Detailed ways

Carry out a kind of slurry catalyst that is used for the preparation method of slurry bed synthesis gas ethanol and slurry catalyst provided by the present invention, and its described slurry catalyst is a kind of M-Cu/ZnO/Al ₂ O ₃ catalyst , in which M and Cu are the active components, ZnO is the structural aid, and Al ₂ O ₃ is the carrier. The adsorption and dissociation carbon on the M metal surface is used to realize the carbon chain growth and complete the CC formation and the CO insertion on the Cu metal surface formylation. The invention adopts the idea that the preparation environment is consistent with the use environment, does not adopt the traditional calcination process, but directly heat-treats the catalyst precursor gel in a solvent to obtain a slurry catalyst.

Below by embodiment the specific embodiment of the present invention is further described:

Example 1

(1) 65 g Cu(NO ₃ ) ₂ and 36 g Zn(NO ₃ ) ₂ were dissolved in 60 ml ethanol at room temperature;

(2) Heat 90ml of distilled water to 82°C, slowly add 20g of aluminum isopropoxide, stir and hydrolyze for 2 hours;

(3) Heat step (2) to 95°C, add an appropriate peptizer, control the pH at about 3-4, and stir for 1.5 hours to obtain a sol;

(4) Add the solution obtained in step (1) dropwise to the sol in step (3), then add dropwise an appropriate amount of 0.5 mol.L ^-1 ferric nitrate solution, stir evenly, and age at room temperature for 15 days to obtain the gel precursor;

(5) Put the aged gel in step (4) into 300 ml of solvent, pass through N ₂ and heat-treat at 280°C for 10 hours, and after cooling, the slurry catalyst of the present invention is obtained. Recorded as Cat-01;

(6) Put the slurry catalyst obtained in step (5) into a slurry bed and reduce it with 20% H ₂ for 12 hours, then feed synthesis gas at a pressure of 5 MPa and a temperature of 250°C. The gas chromatography external standard method was used for reaction tail gas analysis, including two detectors, FID (TDX-01 chromatographic column) and TCD (GDX-502 chromatographic column), the TCD and FID were connected in parallel, and the carrier gas was Ar. Use FID to detect methanol, ethanol, n-, isopropanol and isobutanol and other oxygenated compounds, C ₁ to C ₅ hydrocarbons, and TCD to detect H ₂ , CO, CO ₂ , H ₂ O and CH ₄ . The catalyst activity evaluation results are shown in Table 1.

(1)-(4) Prepare the catalyst precursor for the sol-gel method, hoping to obtain a catalyst with good dispersion of fine particles; the amount of ferric nitrate added is very important, and the present invention mainly utilizes the synergistic effect of iron-based compounds and Cu to grow carbon chain and generate oxygen-containing compounds, if the amount is too much, a large amount of hydrocarbons and long-chain alcohols will be obtained, and a large amount of methanol will be obtained if the amount is too small; step (5) is that the heat treatment link of the present invention does not use roasting, but directly puts the gel into Heating and decomposing nitrate in the reaction solvent to obtain metal oxides not only avoids sintering and provides an environment consistent with the reaction, but also retains the anion components that have not yet been determined in the catalyst production process; step (6) is mainly the catalyst For evaluation, its performance index is calculated based on the value measured by the detection device described in step (6). Factors such as operating temperature, pressure, synthesis gas composition, and space velocity during catalyst evaluation all affect product composition and distribution. In short, catalysts are complex integrated systems, and each link has an impact on the final composition.

A kind of M-Cu/ZnO/Al ₂ O ₃ catalyst described in the above implementation of the present invention solves the problem of carbon chain growth and formylation into alcohol. preparation cost.

In the method for preparing a M-Cu/ZnO/Al ₂ O ₃ catalyst described in the above implementation of the present invention, the traditional roasting is omitted and then dispersed in an inert solvent to become a slurry catalyst, but directly formed from the precursor gel in the The heat treatment is carried out in the solvent, and the catalyst preparation environment is consistent with the slurry bed reaction environment, which greatly improves the uniformity, fluidity and stability of the catalyst.

A kind of M-Cu/ZnO/Al ₂ O ₃ catalyst described in the above implementation of the present invention, each component of metering is heat-treated in a solvent to become a slurry catalyst, which avoids the loss of catalyst components and solves the problem of low metering accuracy .

Give 5 examples again in order to further describe the specific embodiment of the present invention with respect to embodiment below:

Example 2

(1) The steps are the same as in Example 1;

(2) Heat the solution obtained in step (1) to 80°C, slowly add 20 g of aluminum isopropoxide, and stir for 2 hours for hydrolysis;

(3) Heat step (3) to 95°C, add an appropriate peptizer, control the pH to about 3-4, and stir for 1.5 hours to obtain a sol;

(4) Add 20 mL of 0.5 mol.L ^-1 cobalt nitrate solution dropwise in step (3), stir well, and then age at room temperature for 360 hours to obtain the gel precursor;

(5) Put the aged gel in step (4) into 300 mL of solvent, pass through N ₂ for heat treatment at 280°C for 15 hours, and after cooling, it will become a slurry catalyst. Recorded as Cat-02;

(6) Put the slurry catalyst obtained in step (5) into a slurry bed and reduce it with 20% H ₂ for 12 hours, then feed synthesis gas at a pressure of 5 MPa and a temperature of 250°C. The gas chromatography external standard method was used for reaction tail gas analysis, including two detectors, FID (TDX-01 chromatographic column) and TCD (GDX-502 chromatographic column), the TCD and FID were connected in parallel, and the carrier gas was Ar. Use FID to detect methanol, ethanol, n-, isopropanol and isobutanol and other oxygenated compounds, C ₁ to C ₅ hydrocarbons, and TCD to detect H ₂ , CO, CO ₂ , H ₂ O and CH ₄ . The catalyst activity evaluation results are shown in Table 1.

Example 3

(1) 65 g Cu(NO ₃ ) ₂ and 36 g Zn(NO ₃ ) ₂ were dissolved in 120 ml distilled water at room temperature;

(2) Heat the step (1) to 82°C, slowly add 20 g of aluminum isopropoxide, stir and hydrolyze for 2 hours;

(3) Heat step (2) to 95°C, add an appropriate peptizer, control the pH to about 3-4, and stir for 1.5 hours to obtain a sol;

(4) Add the liquid obtained in step (1) dropwise to the sol in step (3), then add dropwise 20 mL of 0.5 mol.L ^-1 nickel nitrate solution, stir evenly, and age at room temperature for 360 hours to obtain the gel precursor;

(5) Put the aged gel in step (4) into 300ml of solvent, pass through N ₂ and heat-treat at 280°C for 15 hours. After cooling, it will become a slurry catalyst. Recorded as Cat-03;

(6) Put the slurry catalyst obtained in step (5) into a slurry bed and reduce it with 20% H ₂ for 12 hours, then feed synthesis gas at a pressure of 5 MPa and a temperature of 250°C. The gas chromatography external standard method was used for reaction tail gas analysis, including two detectors, FID (TDX-01 chromatographic column) and TCD (GDX-502 chromatographic column), the TCD and FID were connected in parallel, and the carrier gas was Ar. Use FID to detect methanol, ethanol, n-, isopropanol and isobutanol and other oxygenated compounds, C ₁ to C ₅ hydrocarbons, and TCD to detect H ₂ , CO, CO ₂ , H ₂ O and CH ₄ . The catalyst activity evaluation results are shown in Table 1.

Example 4

(1) 65 g Cu(NO ₃ ) ₂ and 36 g Zn(NO ₃ ) ₂ were dissolved in 120 ml distilled water at room temperature;

(2) Dissolve 20 g of aluminum isopropoxide in 60 mL of a mixed solution of isopropanol and ethanol, and set aside;

(3) Heat step (1) to 82°C, slowly add (2) aluminum isopropoxide solution, stir and hydrolyze for 2 hours; then heat to 95°C, add appropriate peptizer, control pH to about 3-4, stir for 1.5 hours to get the sol;

(4) Add 20 mL of 0.5 mol.L ^-1 ferric nitrate solution and 0.5 mol.L ^-1 cobalt nitrate solution dropwise in step (3), stir well, and age at room temperature for 360 hours to obtain the gel precursor;

(5) Put the aged gel in step (4) into 300 mL of solvent, pass through N ₂ for heat treatment at 280 °C for 15 hours, and prepare the slurry catalyst after cooling. Recorded as Cat-04;

(6) Put the slurry catalyst obtained in step (5) into a slurry bed and reduce it with 20% H ₂ for 12 hours, then feed synthesis gas at a pressure of 5 MPa and a temperature of 250°C. The gas chromatography external standard method was used for reaction tail gas analysis, including two detectors, FID (TDX-01 chromatographic column) and TCD (GDX-502 chromatographic column), the TCD and FID were connected in parallel, and the carrier gas was Ar. Use FID to detect methanol, ethanol, n-, isopropanol and isobutanol and other oxygenated compounds, C ₁ to C ₅ hydrocarbons, and TCD to detect H ₂ , CO, CO ₂ , H ₂ O and CH ₄ . The catalyst activity evaluation results are shown in Table 1.

Example 5

(1) Mix and dissolve 65 g Cu(NO ₃ ) ₂ and 36 g Zn(NO ₃ ) ₂ with 120 ml distilled water at room temperature;

(2) Dissolve 20g aluminum isopropoxide with 60mL isopropanol and ethanol mixed solution, set aside;

(3) Heat step (1) to 82°C, slowly add the aluminum isopropoxide solution obtained in step (2), stir and hydrolyze for 2 hours; then heat to 95°C, then add appropriate peptizer, and control the pH to 3- 4 or so, stirred for 1.5 hours to obtain a sol;

(4) Add 20 mL of 0.5 mol.L ^-1 ferric nitrate solution and 0.5 mol.L-1 nickel nitrate mixed solution dropwise in step (3), stir well, and age at room temperature for 360 hours to obtain the gel precursor;

(5) Put the aged gel in step (4) into 300mL solvent, pass through N ₂ and heat-treat at 280°C for 15 hours. After cooling, it will be a slurry catalyst. Recorded as Cat-05;

(6) Put the slurry catalyst obtained in step (5) into a slurry bed and reduce it with 20% H ₂ for 12 hours, then feed synthesis gas at a pressure of 5 MPa and a temperature of 250°C. The gas chromatography external standard method was used for reaction tail gas analysis, including two detectors, FID (TDX-01 chromatographic column) and TCD (GDX-502 chromatographic column), the TCD and FID were connected in parallel, and the carrier gas was Ar. Use FID to detect methanol, ethanol, n-, isopropanol and isobutanol and other oxygenated compounds, C ₁ to C ₅ hydrocarbons, and TCD to detect H ₂ , CO, CO ₂ , H ₂ O and CH ₄ . The catalyst activity evaluation results are shown in Table 1.

Example 6

(1) Mix and dissolve 65 g Cu(NO ₃ ) ₂ and 36 g Zn(NO ₃ ) ₂ with 120 mL distilled water at room temperature;

(2) Dissolve 20g of aluminum isopropoxide in 60mL of a mixed solution of isopropanol and ethanol, and set aside;

(3) Heat step (1) to 82°C, slowly add step (2) aluminum isopropoxide solution, stir and hydrolyze for 2 hours; then heat to 95°C, add appropriate peptizer, control pH to about 3-4, stir Sol was obtained in 1.5 hours;

(4) Add 20 mL of 0.5 mol.L ^-1 cobalt nitrate solution and 0.5 mol.L ^-1 nickel nitrate mixed solution dropwise in step (3), stir well, then age at room temperature for 360 hours to obtain the gel precursor;

(5) Put the aged gel in step (4) into 300 mL of solvent, pass through N ₂ for heat treatment at 280°C for 15 hours, and after cooling, the slurry catalyst is prepared. Recorded as Cat-06;

(6) Put the slurry catalyst obtained in step (5) into a slurry bed and reduce it with 20% H ₂ for 12 hours, then feed synthesis gas at a pressure of 5 MPa and a temperature of 250°C. The gas chromatography external standard method was used for reaction tail gas analysis, including two detectors, FID (TDX-01 chromatographic column) and TCD (GDX-502 chromatographic column), the TCD and FID were connected in parallel, and the carrier gas was Ar. Use FID to detect methanol, ethanol, n-, isopropanol and isobutanol and other oxygenated compounds, C ₁ to C ₅ hydrocarbons, and TCD to detect H ₂ , CO, CO ₂ , H ₂ O and CH ₄ . The catalyst activity evaluation results are shown in Table 1.

Table 1 Catalyst activity evaluation results (calculated by carbon atoms)

Claims (6)

1. a slurry _catalyst for ethanol production from slurry bed synthesis gas, said slurry catalyst is M-Cu/ZnO/Al ₂ O catalyzer, wherein, M and Cu are active components, and ZnO is a structural aid, Al ₂ O ₃ is a carrier, its composition and content are Cu:Zn:Al=2.0:(0.8-1.0):(0.4-0.8) according to the atomic ratio, M is 0.01-0.02%; the said M is Fe system metal compound. 2. The slurry catalyst for preparing ethanol from slurry bed synthesis gas as claimed in claim 1, wherein said Fe-based metal compound is one or both of soluble iron salts, cobalt salts and nickel salts. 3. The slurry catalyst for producing ethanol from slurry bed synthesis gas as claimed in claim 1, wherein said soluble salt is Fe(NO ₃ ) ₃ .9H ₂ O, Co(NO ₃ ) ₂ .6H ₂ O, Ni (NO ₃ ) ₂ .6H ₂ O compound or one of the soluble salts converted from its compound. 4. a kind of preparation method of the slurry catalyst that is used for the preparation of ethanol from slurry bed syngas as claimed in claim 1, its described method is that aluminum salt is hydrolyzed in the water above 80 ℃ earlier, add peptizing agent and adjust pH to be 3-4 Make an aluminum sol; then dissolve the soluble Cu salt and Zn salt to form a water or alcohol solution, slowly add it to the sol, then add the water or alcohol solution of the M compound to the above sol, reflux and stir at a temperature above 95°C, Aging to form a gel; then the gel is directly dispersed in the solvent of the slurry bed reaction, stirred evenly for heat treatment, after the decomposition of Cu salt, Zn salt and M compound is completed, it is reduced by dilute hydrogen or synthesis gas to obtain slurry catalyst. 5. The preparation method of the slurry catalyst for ethanol production from slurry bed syngas as claimed in claim 4, wherein said soluble Cu salt is Cu(NO ₃ ) ₂ .5H ₂ O and Cu(CH ₃ COO) ₂ . One of _H2O . 6. The preparation method of the slurry catalyst for ethanol production from slurry bed syngas as claimed in claim 4, wherein said soluble Zn salt is Zn(NO ₃ ) ₂ .6H ₂ O and Zn(CH ₃ COO) ₂ . One of 2H ₂ O.

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