CN101856619B - High-dispersion load-type iron-based catalyst for co-liquefaction of coal and biomass and preparation method thereof - Google Patents

Abstract

The invention discloses a highly dispersed and loaded iron-based coal and biomass co-liquefaction catalyst and a preparation method thereof. Wherein, the method includes: adding 5wt%-50wt% alkali metal polysulfide or ammonium polysulfide solution to carbon black with a particle size of 10-150nm at a temperature of 800-1500r/min in the range of 20-70°C. Stir at a uniform speed to obtain a carbon black slurry; in a stirring state, add the iron-containing ion solution according to the stoichiometric ratio of polysulfides to the above-mentioned carbon black slurry, and stir evenly to obtain carbon black loaded with polysulfide precipitates. Black slurry; the pH value at the end of the reaction is controlled at 5.0-13.0; the carbon black slurry loaded with iron polysulfide precipitation is subjected to centrifugation or pressure filtration to obtain a highly dispersed load type for coal and biomass co-liquefaction Iron-based catalysts. The catalyst obtained based on the invention has high catalytic activity, simple preparation process, stable operation, easy scale-up and environmental friendliness.

Description

Highly dispersed and loaded iron-based coal-biomass co-liquefaction catalyst and preparation method thereof

technical field

The invention relates to the field of co-liquefaction of coal and biomass, in particular to a highly dispersed and loaded iron-based catalyst for co-liquefaction of coal and biomass and a preparation method thereof.

Background technique

Co-liquefaction of coal and biomass is a process of hydrogenation conversion of coal and biomass under the action of a certain temperature, pressure and catalyst. one of the directions. After more than ten years of research and development, coal and biomass co-liquefaction technology has basically matured. In order to achieve commercially viable coal-biomass co-liquefaction, the development of inexpensive, efficient, and environmentally friendly catalysts is one of the key technologies.

Catalysts for co-liquefaction of coal and biomass can be divided into two categories. The first type is transition metal halides, such as SnCl ₂ , ZnBr ₂ , ZnI _{2 ,} etc., and non-iron catalysts such as cobalt (Co), molybdenum (Mo), nickel (Ni), etc.; the second type is iron-based catalysts, Including iron-containing natural ores, iron-containing industrial waste residues, and various pure iron compounds (such as iron oxides, hydroxides, and sulfides). Studies have shown that halide catalysts have strong cracking ability, but are in a molten state under liquefaction conditions, are highly corrosive and unstable. Although cobalt, molybdenum, nickel, etc. have high catalytic activity, they are all relatively expensive, and they cause serious environmental pollution after being discarded, and need to be recycled after use. Iron-based catalysts are cost-effective, and there is no pollution to the environment when the ash enters. It is the focus and direction of the research and development of coal-biomass co-liquefaction catalysts.

In the domestic and international research on co-liquefaction of coal and biomass, natural pyrite, iron oxides and various smelting waste residues (such as red mud, etc.) are usually used, and the particle size is generally several microns to tens of microns. The amount is as high as 3% of dry coal, and the catalytic effect is limited due to poor dispersion. Studies have shown that the catalytic activity of the catalyst is directly proportional to its dispersion. For example, iron oxyhydroxide is adsorbed on the surface of coal particles in the form of fine particles by impregnation, and a higher liquid yield than other iron-based catalysts can be obtained. Therefore, the finer the catalyst particles, the better the dispersion and the better the catalytic effect in the process of co-liquefaction of coal and biomass. The use of highly dispersed ultra-fine catalysts can not only increase the oil yield, but also reduce the amount of catalyst used to achieve the effects of improving process operation, reducing costs and reducing environmental pollution.

In order to obtain iron-based agents with ultra-fine particle size, scholars from various countries have successively developed a variety of artificial synthesis methods, mainly as follows:

1. Treat raw coal with various iron salt aqueous solutions, and react with alkaline solutions such as ammonia water to form iron hydroxide, making it highly dispersed on the surface of coal, that is, coal adsorption or impregnated catalyst (B RUtz, A V Cuigini. Method for Dispersing Catalyst onto Particulatematerial, 1992, US 5096570. A V Cugini, D Krastman, R G Lett, V DBalsone. Development of a dispersed iron catalyst for first stage coalliquefaction. Catalysis Today, 1994, 19(3): 340-795 Wang Cunyan, Shi Shidong, Shu Geping, Li Ruying, Du Shufeng. Preparation of Slurry Highly Dispersed Iron-Based Coal Liquefaction Catalyst, 2003, CN1109734. Shu Geping, Li Wenbo, Shi Shidong, Li Kejian, Wu Chunlai, Zhou Ming, Du Shufeng, Huo Weidong, He Ping. A highly dispersed iron-based coal liquefaction catalyst and its preparation method, 2006, CN1274415C. Li Wenbo, Shu Geping, Li Kejian, Huo Weidong, Shi Shidong, Du Shufeng, He Ping, Wang Yu, Zhu Xiaosu. A high Dispersed iron-based catalysts. 2006, CN1778871A. Kazuyo Matsuo, Koichi Izumiya, Toshio Hachijum. Manufacturing method of highly active catalysts for coal liquefaction, 2008, CN100361743C. D K Mukherjee, P BChowdhury, J K Sama. Hydrogenation of Coal, 1971, US 3775286.).

2. Japan Lignite Liquefaction Company used ferrous sulfate and ammonia water as raw materials to prepare ferrous hydroxide, then added ammonium hydrogen phosphate, and oxidized in air at 40°C for 20 hours to obtain γ-FeOOH ultrafine particles. Drying at 100°C, the γ-FeOOH ultrafine particles are easy to agglomerate after drying. When used in liquefaction reactions, the agglomerates are pulverized in process solvents to submicron average particle size by ultra-fine milling.

3. Grinding iron-containing substances and coal in liquefaction solvent (waste lubricating oil) to prepare iron-based coal liquefaction catalyst (Li Heming, Wang Jun, Yang Tao, Jia Li, Jia Yongzhong, Yang Guang. An iron-based coal liquefaction catalyst and Its preparation method, 2009, CN 100457261C.)

4. Japan's New Energy Development Organization (NEDO) used a dry process to roast FeSO ₄ and S together to form FeS ₂ , and successfully synthesized an iron sulfide catalyst (SIS) product with a particle size of tens of microns to several microns.

5. Add organic metal compounds such as oil-soluble iron naphthenate or carbonyl iron directly into the liquefaction system, and form highly dispersed metal sulfides in situ with cocatalyst S in the reaction system (W L Yoon, HT Lee, H Chung, D K Lee, B H Lee, Y H Wi, C Y Kim. First-stage direct liquefaction of a subbituminous coal with oil-solublemetal naphthenates as dispersed catalyst precursors. Fuel, 1997, 76(5): 397-405 .)

6. Using laser cracking technology (J M Stencel, PC Eklund, X X Bi, F JDerbyshire. Iron ultrafine particle catalysts formed by laser pyrolysis: synthesis, characterization and coalliquefaction activity. Catalysis Today, 1992, 15(2): 285-306.PC Eklund, X X Bi.Synthesis of single phase α-Fe, Fe ₃ C and Fe ₇ C ₃ nano-particles by CO ₂ laser pyrolysis technique.Technical Report, 1992) prepared various nanoscale ultrafine iron-based catalysts, such as iron carbide ( Fe ₃ C and Fe ₇ C ₃ ), iron nitride (Fe ₃ N and Fe ₄ N), iron sulfide (Fe _1-x S) and α-Fe, etc. All these particles have a particle size ranging from 4nm to 20nm. However, some catalysts spontaneously ignite in air and require passivation before contact with air.

7. Use flame cracking technology to prepare ultrafine particle catalysts, such as burning iron chloride on hydrogen and oxygen flames to form aerosol oxides. The particle diameter of these particles is about 50 nm, and the specific surface area is 20-50 m ² /g.

及

等超强酸催化剂再使用。8. Reverse micellar microemulsion method (DB Dadyburjor, T E Fout, J W Zondlo. Ferric-sulfide-based catalysts made using reverse micelles: Effect of preparation on performance in coal liquefaction. Catalysis Today, 2000, 63 (1): 33- 41. A Martino, J P Wilcoxon, J S Kawola. Synthesis and characterization of coal liquefaction catalysts in inverse micelles. Energy & Fuels, 1994, 8 (6): 1289-1295.) and common lye and iron salt solution neutralization precipitation method ( V R Pradhan, J W Tierney, I Wender, G P Huffman. Catalysis in directcoal liquefaction by sulfated metal oxides. Energy & Fuels, 1991, 5(3): 497-507. V R Pradhan, D E Herrick, J W Tierney, I Wender. Finely dispersed iron , iron-molybdenum, and sulfated iron oxides as catalysts for coprocessing reactions. Energy & fuels, 1991, 5(5): 712-720). The precipitation method can be used after drying and dehydrating the precipitated Fe(OH) ₂ or Fe(OH) ₃ and FeOOH particles, or by treating the precipitated FeOOH with H ₂ SO ₄ and roasting to form

and

Wait until the superacid catalyst is used again.

To sum up, there are many methods for preparing coal-biomass co-liquefaction catalysts, most of which have high preparation costs (inverted microemulsion method), or the scale of the preparation method is difficult to scale up (laser pyrolysis method and flame pyrolysis method), or the The particle size of the prepared catalyst is too large, and the activity is limited. Therefore, the most competitive potential is the iron-based catalyst prepared by the precipitation method. However, the traditional precipitation reaction conditions are difficult to control, and the particles are easy to agglomerate again, and the particle size of the catalyst formed during drying or roasting will increase sharply. Therefore, It is difficult to prepare highly dispersed ultrafine particle catalysts without taking special measures.

Contents of the invention

The purpose of the present invention is to provide a highly dispersed and loaded iron-based coal-biomass co-liquefaction catalyst and its preparation method. The catalyst obtained based on the present invention has high catalytic activity, simple preparation process, stable operation, easy scale-up and environmental friendliness.

On the one hand, the present invention provides a highly dispersed and loaded iron-based coal-biomass co-liquefaction catalyst, which is characterized by: 1) the main composition of the iron-based catalyst is FeSx; 2) the iron-based catalyst contains 2-40% iron, containing Sulfur 10-80%, containing carbon black 1%-70%; 3) x in the highly dispersed and loaded iron-based catalyst for coal and biomass co-liquefaction is an integer of 1-9; 4) the iron-based catalyst is uniformly dispersed on carbon Black surface, long-term stability.

On the other hand, the present invention also provides a method for preparing a highly dispersed and loaded iron-based coal-biomass co-liquefaction catalyst, comprising the following steps: step S1, in the range of 20-70°C, 5wt%-50wt% Alkali metal polysulfide or ammonium polysulfide solution is added to carbon black with a particle size of 10-150nm, and stirred evenly at a speed of 800-1500 rpm to obtain a carbon black slurry; step S2, under stirring, press Add the iron ion-containing solution of polysulfide stoichiometric ratio to the above-mentioned carbon black slurry, and stir evenly to obtain a carbon black slurry loaded with iron polysulfide precipitation; the pH value at the end of the reaction is controlled at 5.0-13.0; step S3 , the carbon black slurry loaded with iron polysulfide precipitation is centrifuged or pressurized to obtain a highly dispersed and loaded iron-based catalyst for co-liquefaction of coal and biomass.

In the above preparation method, preferably in the step S1, the alkali metal polysulfide solution is an aqueous solution of potassium polysulfide or an aqueous solution of sodium polysulfide.

In the above preparation method, preferably in the step S2, the iron ion-containing solution is ferric sulfate, ferric chloride, ferric oxalate or ferric nitrate solution.

In the above preparation method, preferably in the step S2, the pH value at the end of the reaction is further controlled at 6.0-9.0.

In the above preparation method, preferably in the step S1, the particle size of the carbon black is 20nm-70nm.

Compared with the prior art, the present invention has the following advantages:

First, polysulfides are dispersed and adsorbed on the surface of carbon black, and when a solution containing iron ions is added to react, the FeS _x particles produced are not easy to aggregate and grow, and are not easy to agglomerate even in the dehydration process, so it has a high catalytic activity active.

Second, the iron salt used is cheap FeSO ₄ as the starting material, and the final product is an iron-based catalyst composed of FeS _x ; no co-catalyst S is added in the co-liquefaction reaction of coal and biomass.

Description of drawings

Fig. 1 is a flowchart of steps of an embodiment of a method for preparing a highly dispersed and loaded iron-based coal-biomass co-liquefaction catalyst.

Detailed ways

In order to make the above objects, features and advantages of the present invention more comprehensible, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Referring to Fig. 1, Fig. 1 is a step flow chart of an embodiment of a method for preparing a high-dispersion-loaded iron-based coal and biomass co-liquefaction catalyst, including:

Step S1, at room temperature, in the range of 20-70°C, add 5wt%-50wt% alkali metal polysulfide or ammonium polysulfide solution to carbon black with a particle size of 10-150nm, and rotate at 800-1500 Stir evenly at a speed of 1/min to obtain a carbon black slurry; step S2, in a stirring state, add the iron-containing ion solution in the stoichiometric ratio of polysulfides to the above-mentioned carbon black slurry, stir evenly, and obtain polysulfide-containing The carbon black slurry of iron sulfide precipitation; the pH value at the end of the reaction is controlled at 5.0-13.0; step S3, the carbon black slurry loaded with iron polysulfide precipitation is subjected to centrifugal filtration or pressure filtration to obtain coal and raw materials Highly dispersed and loaded iron-based catalysts for co-liquefaction of substances.

The catalyst obtained based on this example has high catalytic activity, simple preparation process, stable operation, easy scale-up and environmental friendliness.

Example 1

The catalyst listed in the present invention uses a carbon black produced by Mitsubishi Corporation of Japan as the carrier for the preparation of the catalyst, and uses ferrous sulfate as the main raw material to obtain a coal and biomass co-liquefaction catalyst sample. Take 3.60kg of sodium polysulfide, add 23.50kg of water to dissolve it, then add 0.5kg of carbon black, and stir evenly to make sodium polysulfide carbon black slurry; take another 4.62kg of FeSO ₄ ·7H ₂ O and add it to 24.35kg of water for dissolution. Under stirring, the above-mentioned solution containing iron ions was added to the above-mentioned carbon black slurry, and the stirring was continued for 15 seconds after the addition, and the pH value was 6.5 at the end of the reaction. The above reaction product is subjected to centrifugal filtration, and the obtained filter cake is the catalyst of the present invention.

Of course, the sodium polysulfide solution can also be replaced by potassium polysulfide or ammonium polysulfide solution. Replace the _FeSO solution with ferric chloride, ferric oxalate, or ferric nitrate solution.

Apply the catalyst of the present invention to a 0.5L high-pressure reactor for co-liquefaction of coal and biomass, using Shenhua coal and lignin as raw materials, tetrahydronaphthalene as a hydrogen-donating solvent, reaction temperature 400°C, pressure 7MPa, coal and biomass The substance slurry concentration is 40%, and the reaction residence time is 1h.

Results obtained with different catalysts

catalyst Addition amount (wt%, dry basis raw material) Total conversion rate (wt%, dry basis raw material) n-Hexane extract (wt%, daf base

material) Chinese gray pyrite (two-stage wet grinding) Raw ore = 4.5 (where Fe = 1.97) 89 45 Catalyst of the present invention Catalyst = 3 (where Fe = 0.5) 90.65 58.76

This shows that catalyst of the present invention obtains equivalent conversion rate with gray two-stage wet grinding pyrite catalyst, but the addition of the former is much less, and the n-hexane extract that obtains is much higher than that obtained by the latter, It shows that the catalyst activity of the present invention is high.

Example 2

The amount of carbon black is changed into 0.75kg, all the other are with embodiment 1, and pH value is 6.5 when reaction finishes. Shenhua coal is used in a 0.5L autoclave, the circulating solvent is a hydrogen-donating solvent, the iron content of the catalyst added is 0.5% of the raw material on a dry basis, the initial pressure of _H2 is 7MPa, the reaction temperature is 400°C, the residence time is 60min, and the analysis results of the reaction product It shows that the THF (tetrahydrofuran) conversion rate is 78.76%, and the n-hexane extract is 51%.

Example 3

The amount of carbon black is changed into 0.80kg, all the other are with embodiment 1, and pH value is 8.0 when reaction finishes. Use Shengli coal and straw in a 0.5L autoclave, tetrahydronaphthalene as the hydrogen-donating solvent, the iron content of the catalyst added is 0.45% of the dry raw material, the initial pressure of _H2 is 8MPa, the reaction temperature is 395 ° C, the residence time is 90min, and the reaction The product analysis results showed that the THF (tetrahydrofuran) conversion rate was 82.63%, the n-hexane extract was 72.07%, and the total conversion rate (wt%, dry basis material) was 93.67%.

In the above examples, polysulfide (K ₂ S _x , Na ₂ S _x , (NH ₄ ) ₂ S _x ) solutions are added to carbon black with a particle size of 10-150 nm, and stirred at a speed of 800-1300 r/min Next, add a solution containing iron ions in a stoichiometric ratio, stir evenly, and prepare a carbon black slurry loaded with FeS _x precipitates. The above slurry is subjected to centrifugal filtration or pressure filtration to obtain a highly dispersed and loaded iron-based catalyst for co-liquefaction of coal and biomass. In a 500ml autoclave, when the amount of iron added in the catalyst is about 0.5wt% of the co-liquefaction raw material on a dry basis, the yield of n-hexane extract reaches more than 57%, and the catalytic activity is higher than that of natural pyrite. Moreover, the process is simple, the operation is convenient, and it is easy to enlarge.

On the other hand, the present invention also discloses a highly dispersed and loaded iron-based coal-biomass co-liquefaction catalyst, the iron-based catalyst is mainly composed of FeSx; the mass percentages of iron, sulfur and carbon black in the iron-based catalyst are respectively: 2-40% of iron, 10-80% of sulfur, 1%-70% of carbon black; the value of x is an integer of 1-10; and the iron-based catalyst is evenly dispersed on the surface of carbon black, which is stable for a long time.

Example 4

A highly dispersed and loaded iron-based coal-biomass co-liquefaction catalyst contains iron polysulfide FeSx, wherein the value of X is 1, and the mass percentages of iron, sulfur, and carbon black in the catalyst are respectively

Iron 18.06%

Sulfur 10.32%

Carbon black 64.52%

Example 5

A highly dispersed and loaded iron-based coal and biomass co-liquefaction catalyst contains iron polysulfide FeSx, wherein the value of X is 6, and the mass percentages of iron, sulfur and carbon black in the catalyst are respectively

Iron 6.07%

Sulfur 20.81%

Carbon black 54.20%

Example 6

A highly dispersed and loaded iron-based coal and biomass co-liquefaction catalyst, containing iron polysulfide FeSx, wherein, the value of X is 9 In the catalyst, the mass percentages of iron, sulfur, and carbon black are respectively

Iron 5.27%

Sulfur 27.11%

Carbon black 47.06%

Example 7

A highly dispersed and loaded iron-based coal-biomass co-liquefaction catalyst, containing iron polysulfide FeSx, wherein the mass percentage content of iron, sulfur, carbon black and the value of X are:

Iron 2%

Sulfur 10.39%

Carbon black 56.78%

The value of X is 9

Example 8

A highly dispersed and loaded iron-based coal-biomass co-liquefaction catalyst, containing iron polysulfide FeSx, wherein the mass percentage content of iron, sulfur, carbon black and the value of X are:

Iron 21.74%

Sulfur 49.69%

Carbon black 23.98%

The value of X is 4

Example 9

A highly dispersed and loaded iron-based coal-biomass co-liquefaction catalyst, containing iron polysulfide FeSx, wherein the mass percentage content of iron, sulfur, carbon black and the value of X are:

Iron 39.97%

Sulfur 45.71%

Carbon black 11.56%

The value of X is 3

Example 10

A highly dispersed and loaded iron-based coal-biomass co-liquefaction catalyst, containing iron polysulfide FeSx, wherein the mass percentage content of iron, sulfur, carbon black and the value of X are:

Iron 8.75%

Sulfur 9.94%

Carbon black 63.87%

The value of X is 2

Example 11

A highly dispersed and loaded iron-based coal-biomass co-liquefaction catalyst, containing iron polysulfide FeSx, wherein the mass percentage content of iron, sulfur, carbon black and the value of X are:

Iron 26.25%

Sulfur 44.87%

Carbon black 23.14%

The value of X is 3

Example 12

A highly dispersed and loaded iron-based coal-biomass co-liquefaction catalyst, containing iron polysulfide FeSx, wherein the mass percentage content of iron, sulfur, carbon black and the value of X are:

Iron 15.56%

Sulfur 79.78%

Carbon black 3.78%

The value of X is 9

Example 13

A highly dispersed and loaded iron-based coal-biomass co-liquefaction catalyst, containing iron polysulfide FeSx, wherein the mass percentage content of iron, sulfur, carbon black and the value of X are:

Iron 16.50%

Sulfur 75.43%

Carbon black 1.09%

The value of X 8

Example 14

A highly dispersed and loaded iron-based coal-biomass co-liquefaction catalyst, containing iron polysulfide FeSx, wherein the mass percentage content of iron, sulfur, carbon black and the value of X are:

Iron 12.21%

Sulfur 41.87%

Carbon black 37.57%

The value of X 6

Example 15

A highly dispersed and loaded iron-based coal-biomass co-liquefaction catalyst, containing iron polysulfide FeSx, wherein the mass percentage content of iron, sulfur, carbon black and the value of X are:

Iron 4.59%

Sulfur 18.35%

Carbon black 69.96%

The value of X is 7

The above is a detailed introduction of a highly dispersed and loaded iron-based coal-biomass co-liquefaction catalyst and its preparation method provided by the present invention. In this paper, specific examples are used to illustrate the principle and implementation of the present invention. The above examples The description is only used to help understand the method and core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation and application scope. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims (1)

1. the preparation method of high-dispersion load-type iron-based coal and living beings catalyst for co-liquefaction is characterized in that high-dispersion load-type iron-based coal and living beings catalyst for co-liquefaction are:

1) ferrum-based catalyst mainly consists of FeSx;

2) iron content 2-40% in the ferrum-based catalyst, sulfur-bearing 10-80%, carbon black 1%-70%;

3) coal and living beings liquefy altogether and use the x in the high-dispersion load-type iron-based catalyst to be the integer of 1-9;

4) ferrum-based catalyst is dispersed in black carbon surface, long-term stability;

Comprise the steps:

Step S1 in 20～70 ℃ of scopes, joins alkali metals polysulfide or the ammonium polysulfide solution of 5wt%～50wt% in the carbon black that particle diameter is 10～150nm, stirs with 800～1500 rev/mins speed, obtains the carbon black slurry;

Step S2 under stirring, joins in the above-mentioned carbon black slurry by the ferric ion solutions that contains of polysulfide stoichiometric proportion, stirs, and makes the carbon black slurry that is loaded with many iron sulfide depositions; The pH value of reaction end is controlled at 5.0-13.0;

Step S3 makes coal and living beings with the said carbon black slurry that is loaded with many iron sulfide deposition through centrifugal filtration or pressure filtration and liquefies altogether and use high-dispersion load-type iron-based catalyst;

Among the said step S1, described alkali metals polysulfide solution is the aqueous solution of potassium polysulfide or the aqueous solution of sodium polysulfide;

Among the said step S2, the described ferric ion solutions that contains is ferric sulfate, iron chloride, ferric oxalate or iron nitrate solution;

Among the said step S2, the pH value of said reaction end further is controlled at 6.0-9.0;

Among the said step S1, the particle diameter of said carbon black is 20nm-70nm.

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