阅读说明：本技术 煤直接液化铁系催化剂及其制备方法 (Iron-based catalyst for direct coal liquefaction and preparation method thereof ) 是由 谢晶 舒歌平 王洪学 章序文 杨葛灵 高山松 单贤根 李导 于 2020-03-12 设计创作，主要内容包括：本发明涉及煤化工领域,公开了一种煤直接液化铁系催化剂的制备方法。本发明的煤直接液化铁系催化剂的制备方法包括如下步骤：(1)将铁盐溶液和含氨溶液连续送入到雾化喷头中进行雾化形成雾化液滴,并使所述雾化液滴与煤粉接触,得到负载有含铁活性成分的半干催化剂；(2)将步骤(1)得到的半干催化剂进行干燥,得到煤直接液化铁系催化剂。本发明的催化剂分散性好,煤直接液化催化活性高,催化剂生产过程简单,易于工业放大,生产效率高,水的用量少,并且不产生废水。(The invention relates to the field of coal chemical industry, and discloses a preparation method of a direct coal liquefaction iron catalyst. The preparation method of the iron catalyst for direct coal liquefaction comprises the following steps: (1) continuously feeding an iron salt solution and an ammonia-containing solution into an atomizing nozzle for atomizing to form atomized liquid drops, and contacting the atomized liquid drops with coal powder to obtain a semi-dry catalyst loaded with an iron-containing active component; (2) and (2) drying the semi-dry catalyst obtained in the step (1) to obtain the direct coal liquefaction iron catalyst. The catalyst has the advantages of good dispersibility, high catalytic activity of direct coal liquefaction, simple production process, easy industrial amplification, high production efficiency, small water consumption and no wastewater generation.)

1. A preparation method of a direct coal liquefaction iron catalyst is characterized by comprising the following steps:

(1) continuously feeding an iron salt solution and an ammonia-containing solution into an atomizing nozzle for atomizing to form atomized liquid drops, and contacting the atomized liquid drops with coal powder to obtain a semi-dry catalyst loaded with an iron-containing active component;

(2) and (2) drying the semi-dry catalyst obtained in the step (1) to obtain the direct coal liquefaction iron catalyst.

2. The preparation method according to claim 1, wherein in the step (1), the iron content in the iron salt solution is 7-20 wt%, more preferably 9-15 wt%;

preferably, the ferric salt solution is a solution of one or more of nitrate, sulfate, acetate and chloride of ferric iron and/or ferrous iron;

more preferably, the ferric salt solution is a solution of ferrous sulfate and/or ferric sulfate.

3. The production method according to claim 1, wherein in the step (1), the ammonia content of the ammonia-containing solution is 15 to 40 wt%;

preferably, the ammoniated solution is ammonia.

4. The preparation method according to claim 1, wherein in the step (1), the feeding flow ratio of the ferric salt solution to the ammonia-containing solution is 3.5-6: 1;

preferably, the reaction temperature of the ferric salt solution and the ammonia-containing solution is 40-70 ℃.

5. The production method according to any one of claims 1 to 4, wherein in the step (1), the molar ratio of the ammonia-containing solution in terms of ammonia to the iron salt solution in terms of elemental iron is 1: 0.3-2.

6. The production method according to any one of claims 1 to 4, wherein in step (1), the feed flow ratio of the pulverized coal to the atomized liquid droplets is 2 to 4: 1;

preferably, the contact time is 1 minute or more.

7. The production method according to any one of claims 1 to 4, wherein in step (1), the diameter of the liquid droplet is 2mm or less;

preferably, the contacting is performed by an absorption mixer;

preferably, the absorption mixer is a barrel type continuous mixer with a stirring shaft arranged therein, and more preferably, the barrel type continuous mixer is provided with a stirring shaft arranged therein and an outer barrel capable of rotating.

8. The preparation method according to any one of claims 1 to 4, wherein, in the step (1), the moisture content of the semi-dry catalyst is 10 to 30 wt%;

preferably, the pulverized coal has a particle size of 150 μm or less and a moisture content of less than 3 wt%.

9. The production method according to any one of claims 1 to 4, wherein, in the step (2), the temperature of the drying is 80 to 220 ℃;

preferably, the iron content of the direct coal liquefaction iron-based catalyst is 3-5.5 wt%, the water content is less than 3 wt%, and the particle size is less than 150 μm;

preferably, the drying is carried out using a drum drying machine through which hot air is passed.

10. The iron-based catalyst for direct coal liquefaction prepared by the preparation method according to any one of claims 1 to 9.

Technical Field

The invention relates to the field of coal chemical industry, in particular to a preparation method of a direct coal liquefaction iron catalyst.

Background

China is rich in coal and deficient in oil, and the external dependence of oil in 2018 reaches 69.8%. The continuous improvement of the external dependence of crude oil means that the situation of social production and energy safety in China is more severe. The advantages of Chinese coal resources are fully utilized, the development, popularization and application of clean coal technology are accelerated, the coal liquefaction industrialization is vigorously developed, and the method is an important choice for guaranteeing the energy safety of China.

Direct coal liquefaction is a clean coal technology that converts coal into liquid products under the conditions of high temperature and high pressure by the action of a hydrogen-donating solvent and a catalyst. The catalyst plays an important role in the direct coal liquefaction, can effectively promote the coal pyrolysis and hydrogenation, and improves the yield of the generated oil and the quality of the oil product. In the course of research over the last hundred years, direct coal liquefaction catalysts have been divided into three systems, an iron-based catalyst, including various sulfur-containing natural iron ores, synthetic iron sulfides, synthetic iron oxides and hydroxides, and iron-containing compounds; the second is Ni and Mo series catalyst, including various Ni and Mo oxides, sulfides, salts containing Ni and Mo and organic complex; and thirdly molten chlorides of Zn, Sn, etc. There has been a great deal of research and corresponding advanced technology for three systems of catalysts. Among them, the iron catalyst is relatively cheap, widely available, has good effect in coal liquefaction reaction, does not need to be recovered, and has high cost performance, so the iron catalyst is most widely researched and applied.

In the direct coal liquefaction reaction system, coal and a catalyst are dispersed in a solvent (coal pyrolysis intermediate products may be partially dissolved in the solvent); the hydrogen in the gas phase diffuses and dissolves into the solvent and is then adsorbed and activated by the catalyst dispersed therein. More hydrogen can be activated by increasing the activity of the catalyst or increasing the probability of dissolved hydrogen contacting the catalyst. The iron in the iron catalyst reacts with sulfur to produce pyrrhotite (Fe)_1-xS) can generate activity, the crystal phase, the grain size and the like of the iron precursor can generate Fe_1-xThe S structure and the catalytic performance have certain influence, for example, the activity of small-grain gamma-FeOOH is higher. However, since hydrogen needs to enter a solvent to be activated by the catalyst, and the dispersibility of the iron catalyst has a larger influence on the coal liquefaction result than the activity difference of iron catalysts with different structures, researchers also focus more on synthesizing ultra-fine and highly dispersed iron-based catalysts to improve the contact probability of iron active species and dissolved hydrogen. E.g., Andrew et al by decomposition of FeCl in a hydrogen-oxygen flame₃Steam, Preparation of iron particles with an average particle size of about 50nm (Preparation of Catlyst III (eds. Poncelet and Grange), Elsevier Science Publishers,1983, 675-682.); L inehan et al prepared micro-iron oxide particles with a particle size as small as 1nm by reverse phase micelle and fast pyrolysis (ACS FuelChem. Prepr.1992,37(1):488-496), and ultra-fine and nano-iron sulfide catalysts (Energy) by aerosol and microencapsulation techniques, respectively&Fuels.1996,10(3): 757-; CN101947472A discloses a method for using oleic acid coated iron type ferric oxide nanocrystalline as a direct coal liquefaction catalyst. The superfine iron catalysts prepared by the methods have high coal liquefaction activity, but the raw material cost is too high, or the preparation process or the used equipment are complex and the production is difficult to be continuous, so that the method is not beneficial to cost saving and large-scale development and application. Furthermore, CN1231326A and CN1579623A discloses a catalyst with coal liquefaction raw material coal powder as a carrier to load iron, which adopts a liquid phase precipitation method to precipitate iron elements on the surface of the coal powder, and utilizes the adsorption force of the inner and outer surfaces of coal powder particles to play a role in inhibiting secondary aggregation among the surrounding iron primary precipitated particles. However, liquid phase precipitation processes often require more water and produce more waste water, and the process is somewhat limited for use in water deficient and environmentally vulnerable areas.

In addition to the above processes, the solution or precipitate containing iron is dispersed into small droplets by using an atomization technology, the droplets are absorbed by the pulverized coal and gradually permeate into the internal pore channels of the pulverized coal after contacting the pulverized coal, and along with the permeation of the droplets, the iron-containing substances are fixed by the adsorption force of the outer surfaces and the surfaces of the internal pore channels of the pulverized coal particles, and cannot be aggregated in the subsequent filtration and drying processes to finally form uniform load. The preparation process of the catalyst based on the absorption method has three advantages, firstly, the catalyst product can be obtained only by two steps of absorption and drying, the equipment such as stirring, conveying, reaction, filtering and the like in the liquid-phase precipitation method process can be omitted, and the investment and the operation cost are greatly reduced; secondly, only a small amount of fresh water is needed to prepare a high-concentration raw material solution, the water consumption is very low, and no waste water is discharged; thirdly, the pulverized coal forms a semi-dry state after the atomization reaction, and then the next step of drying and oxidation is carried out, so that the energy consumption for drying and grinding the filter cake can be greatly reduced compared with a liquid phase precipitation method. However, in order to maintain the activity of the catalyst, two problems must be solved: 1) whether the iron oxide catalyst with high activity can be prepared under the condition of using high-concentration raw materials or not; 2) whether the uniform load of the iron oxide on the inner pore canal and the outer surface of the coal dust particle can be realized under the dry phase condition.

Disclosure of Invention

The invention aims to overcome the problems in the preparation of the direct coal liquefaction iron catalyst in the prior art, and provides the direct coal liquefaction iron catalyst and the preparation method thereof.

In order to achieve the above object, one aspect of the present invention provides a method for preparing an iron-based catalyst for direct coal liquefaction, the method comprising the steps of:

(1) continuously feeding an iron salt solution and an ammonia-containing solution into an atomizing nozzle for atomizing to form atomized liquid drops, and contacting the atomized liquid drops with coal powder to obtain a semi-dry catalyst loaded with an iron-containing active component;

(2) and (2) drying the semi-dry catalyst obtained in the step (1) to obtain the direct coal liquefaction iron catalyst.

Preferably, in step (1), the iron content in the iron salt solution is 7-20 wt%, more preferably 9-15 wt%.

Preferably, in the step (1), the ferric salt solution is a solution of one or more of nitrate, sulfate, acetate and chloride of ferric iron and/or ferrous iron; more preferably, the ferric salt solution is a solution of ferrous sulfate and/or ferric sulfate.

Preferably, in step (1), the ammonia-containing solution has an ammonia content of 15 to 40 wt.%.

Preferably, in step (1), the ammoniated solution is ammonia water.

Preferably, in step (1), the feed flow ratio of the ferric salt solution to the ammonia-containing solution is 3.5-6: 1.

preferably, in the step (1), the reaction temperature of the ferric salt solution and the ammonia-containing solution is 40-70 ℃.

Preferably, in the step (1), the feeding molar ratio of the ammonia-containing solution calculated by ammonia to the iron salt solution calculated by iron element is 1: 0.3-2.

Preferably, in the step (1), the feeding flow ratio of the pulverized coal to the atomized liquid droplets is 2-4: 1.

preferably, in step (1), the contact time is 1 minute or more.

Preferably, in step (1), the diameter of the droplet is 2mm or less.

Preferably, in step (1), the contacting is performed by an absorption mixer; more preferably, the absorption mixer is a barrel type continuous mixer with a stirring shaft arranged therein, and more preferably, the absorption mixer is a barrel type continuous mixer with a stirring shaft arranged therein and a rotatable outer barrel;

preferably, in the step (1), the moisture content of the semi-dried catalyst is 10 to 30 wt%.

Preferably, in the step (1), the pulverized coal has a particle size of 150 μm or less and a moisture content of less than 3 wt%.

Preferably, in the step (2), the drying temperature is 80-220 ℃;

preferably, in the step (2), the iron content of the iron-based catalyst for direct coal liquefaction is 3-5.5 wt%, the water content is less than 3 wt%, and the particle size is less than 150 μm.

Preferably, in the step (2), the drying is performed by using a roller drying machine through which hot air is introduced.

The second aspect of the present invention provides the above-mentioned iron-based catalyst for direct coal liquefaction prepared by the preparation method of the present invention.

According to the technical scheme, the high-concentration iron salt solution and the ammonia-containing solution can be pressurized and then continuously fed to the atomizing nozzle, rapid mixing reaction is carried out in the nozzle, the iron salt solution and the ammonia-containing solution are atomized into micro liquid drops through the nozzle, and then the micro liquid drops enter the absorption mixer to be absorbed by the turned coal powder, and the high-activity direct coal liquefaction iron catalyst is prepared through drying.

The inventor of the invention finds that the influence of the concentration of ferric salt and the concentration of ammonia water serving as a precipitator on the activity of the catalyst is very large, the iron catalyst with higher activity can be synthesized by using a raw material solution with lower concentration and alkali liquor with lower concentration, but the preparation efficiency is lower, and the production is not facilitated; while too high a feed concentration can result in a rapid decrease in catalyst activity. By adopting the preparation method, the ferric salt solution with higher concentration can be used as an iron source, and the ammonia water with higher concentration can be used as a precipitator, so that the production efficiency of the catalyst can be improved, and the water consumption for the production of the catalyst can be reduced, which is an important aim of the invention; meanwhile, the preparation method provided by the invention realizes the preparation of the high-activity catalyst by using the high-concentration raw material solution.

In the preparation method of the catalyst, firstly, ferric salt solution and ammonia-containing solution are pressurized and conveyed into an atomizing nozzle, so that iron ions in the ferric salt solution are continuously precipitated to generate nanoscale iron precipitation particles, and the nanoscale iron precipitation particles are atomized and sprayed out from a nozzle to form micron-sized liquid drops. In the process, the environment with high pH value during iron precipitation is controlled by adjusting the feeding ratio of the ferric salt solution to the ammonia-containing solution, and the ferric salt solution and the ammonia-containing solution in the atomizing nozzle are collided rapidly to generate precipitation reaction, so that the generation of iron active precursor species with a target crystal phase is ensured; preferably, the two solutions are pressurized and then divided into a plurality of strands to enter the atomizer, the two solutions are sprayed out from a plurality of small holes in the upper part of the atomizer in an accelerating manner to form droplets to enter the inner space of the atomizer, meanwhile, a strand of compressed gas is introduced into the atomizer, so that the iron salt solution droplets and the ammonia-containing solution droplets contact and collide with each other in the inner space of the atomizer under the impact of the compressed gas to generate iron precipitation reaction, and iron-forming precipitates are sprayed out from a nozzle in the lower part of the atomizer to form iron precipitation droplets, and the process realizes the possibility of preparing high-activity components from high-concentration raw materials. Secondly, the atomized micron-sized liquid drops enter the mixing reactor to be absorbed by the pulverized coal stirred to within 150 microns, and the pulverized coal absorbing the iron active precursor is stir-fried, extruded, scattered and the like by components in the absorption mixer cylinder and moves forwards along the radial direction; in the process, the iron active precursor can be rapidly dispersed and transferred among the coal dust particles and infiltrated and migrated on the inner surface and the outer surface of the coal dust particles to form thin layer adsorption, and finally the iron active precursor can be uniformly loaded on a macroscopic layer and a microscopic layer, so that the guarantee is provided for realizing high activity of the catalyst on a physical dispersion layer. Finally, the semi-dry catalyst absorbed with the iron active precursor is continuously conveyed into a roller drying plate dryer for drying. In the process, under the conditions of stirring the shoveling plate and blowing hot air, the coal dust adsorbing the iron primary precipitate is gradually dried and recovered to be in a powder state close to the original feeding coal dust particle size, the dried product is discharged without ball milling, the particle size requirement of coal liquefaction feeding can be met, and the equipment investment and production energy consumption for catalyst preparation are greatly saved.

Therefore, the preparation method provided by the invention has the following advantages: 1. the preparation of the high-activity direct coal liquefaction catalyst by using the raw material with higher concentration is realized; 2. the preparation process of the catalyst is simple, the production efficiency is high, and large-scale continuous production is extremely easy to realize; 3. no waste water is produced, and the production energy consumption is low. 4. The catalyst has low production cost.

Drawings

Fig. 1 is a flow chart of a method for preparing a direct coal liquefaction iron-based catalyst according to the present invention.

Fig. 2 and 3 are the morphologies of the catalysts prepared according to the methods of the present invention under scanning electron microscopy. Wherein fig. 2 is a topography magnified 5 times and fig. 3 is a topography magnified 5 times.

Description of the reference numerals

1. Ferric salt solution tank 2, ammoniated solution tank 3 and ferric salt solution booster pump

4. Ammonia-containing solution booster pump 5, atomizing nozzle 6 and absorption mixer

7. Pulverized coal storage tank 8, conveying belt 9 and shoveling plate dryer

10. Cloth bag dust collector 11, catalyst storage tank 12 and hot-blast stove

13. Tail gas circulator

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

The invention provides a preparation method of a direct coal liquefaction iron catalyst, which comprises the following steps:

(1) continuously feeding an iron salt solution and an ammonia-containing solution into an atomizing nozzle for atomizing to form atomized liquid drops, and contacting the atomized liquid drops with coal powder to obtain a semi-dry catalyst loaded with an iron-containing active component;

(2) and (2) drying the semi-dry catalyst obtained in the step (1) to obtain the direct coal liquefaction iron catalyst.

According to the invention, in the step (1), the ferric salt solution can be a solution of one or more of nitrate, sulfate, acetate and chloride of ferric iron and/or ferrous iron; more preferably, the ferric salt solution is a solution of ferrous sulfate and/or ferric sulfate. By using ferrous sulfate and/or ferric sulfate solution as ferric salt solution, solution with higher iron content can be prepared, and meanwhile, anion sulfate radicals carried by the two ferric salts enter a coal liquefaction reaction system along with a final catalyst product, so that the coal liquefaction catalytic performance is promoted.

Preferably, the iron content of the iron salt solution is 7-20 wt%, more preferably 9-15 wt%. According to the preparation method, the activity of the product catalyst obtained by using the ferric salt solution in the concentration range is controllable; secondly, the active component in the catalyst is iron element, and the iron content of the iron salt solution influences the iron loading amount in the catalyst, thereby influencing the production efficiency of the catalyst. When the iron content in the iron salt solution is low, in order to ensure that the coal dust absorbing liquid drops has fluidity, the amount of the coal dust absorbing liquid drops must be limited, so that the iron content in the catalyst is low, the production efficiency of the catalyst is reduced, and the iron-coal ratio can be ensured by adding more catalysts during the coal liquefaction reaction. When the iron content in the iron salt solution is too high, the difficulty of dissolving the iron salt is increased, the requirement on the heat preservation of pipeline equipment is high, otherwise, the pipeline is easy to be blocked due to crystallization, and secondly, when the iron content in the iron salt solution is too high, the viscosity of iron precipitation slurry generated in a spray head is too high, the atomization is not facilitated, and the risk of blocking the spray head exists; thirdly, when the iron content in the iron salt solution is too high, the dispersibility of iron species on the pulverized coal is deteriorated, resulting in a decrease in the activity of the catalyst.

According to the present invention, in the step (1), the ammonia-containing solution may contain ammonia molecules. Preferably, the ammoniated solution is ammonia. The ammonia content of the ammonia-containing solution is preferably 15 to 40 wt%, more preferably 20 to 35 wt%, and further preferably 20 to 30 wt%. By using the ammonia-containing solution of the above concentration, it is possible to prevent the catalyst production efficiency from being lowered due to the excessively low concentration of the ammonia-containing solution; and can prevent the catalyst from being difficult to generate high-activity FeOOH crystal phase species due to the excessively high concentration of ammonia water, thereby causing the reduction of the catalytic activity.

According to the invention, in step (1), the feed flow ratio (weight ratio) of the ferric salt solution to the ammonia-containing solution is 3.5-6: 1, for example, may be 3.5: 1. 4: 1. 4.5: 1. 5: 1. 5.5: 1 or 6: 1. by carrying out the reaction at the above feed flow ratio, the reaction can be ensured to be carried out in a proper pH environment, thereby ensuring that more catalysts with higher activity are generated. When the feed flow ratio of the ferric salt solution to the ammonia-containing solution is too low, more iron active precursors are generated by iron oxides with larger granularity, and the activity is lower; when the feeding flow ratio of the ferric salt solution to the ammonia-containing solution is too high, iron cannot be completely precipitated, and the generated iron precursor has a relatively complex crystalline phase and low activity. The above feed flow ratio can be measured by a metering pump.

According to a preferred embodiment of the present invention, in order to further improve the coal liquefaction conversion rate and the oil yield of the catalyst obtained, the feed molar ratio of the ammonia-containing solution in terms of ammonia to the iron salt solution in terms of iron element is 1: 0.3 to 2, preferably 1: 0.4 to 0.8, more preferably 1: 0.45 to 0.8, more preferably 1: 0.49-0.76.

According to the invention, in the step (1), the reaction temperature of the ferric salt solution and the ammonia-containing solution is 40-70 ℃. By carrying out the reaction at the above temperature, the performance of the resulting catalyst can be further improved.

According to the invention, in the step (1), the iron salt solution and the ammonia-containing solution are continuously fed into the atomizer for atomization, which means that the iron salt solution and the ammonia-containing solution are simultaneously and continuously fed into the atomizer for atomization and react with each other to obtain atomized droplets of a reaction product slurry mixture. The diameter of the mist droplets is preferably 2mm or less.

The atomizer used for atomization is not particularly limited, and any atomizer that can be used for atomization of a liquid can be used. Specifically, the iron salt solution and the ammonia-containing solution are respectively conveyed (preferably pressurized and then conveyed) to the atomizing nozzle, and a flow guide structure is arranged in the atomizing nozzle, so that two streams of liquid can be rapidly mixed and reacted in the atomizing nozzle to form atomized liquid drops. For example, a plurality of (e.g., 3 or more) iron salt solution inlets and ammonia containing solution inlets may be provided in the atomizing head to form droplets of the two solutions, and a compressed gas inlet may be provided to allow the iron salt solution droplets and the ammonia containing solution droplets to contact and collide with each other in the internal space of the head under the impact of compressed gas to cause precipitation reaction of iron; preferably, the iron salt solution inlet and the ammonia containing solution inlet are arranged centrally symmetrically around the compressed gas inlet. The atomized droplets are atomized droplets of a slurry mixture of iron hydroxide precipitate and optional ammonium sulfate byproduct generated after the reaction of iron ions and ammonia, wherein the precipitate is a nanoscale precipitate.

According to the invention, in the step (1), the semi-dry catalyst loaded with the iron-containing active component is obtained by contact reaction of atomized liquid drops and coal powder. Preferably, the pulverized coal has a particle size of 150 μm or less and a moisture content of less than 3 wt%. By using the coal powder, on one hand, the iron precipitation slurry can be better infiltrated on the inner surface and the outer surface of coal powder particles to achieve the effect of more uniform distribution, so that the activity of the catalyst is improved, and on the other hand, the particle size of the prepared semi-dry catalyst can be kept to be not more than 150 mu m after the prepared semi-dry catalyst is dried by a simple roller shoveling plate, so that the semi-dry catalyst can be directly used for preparing coal slurry by coal liquefaction, and the energy consumption during drying and grinding is greatly reduced.

According to the invention, in step (1), the ratio of the feed flow rates (weight ratio) of the pulverized coal to the atomized liquid droplets is 2-4: 1, preferably 2.5 to 3.5: 1. the time for the contact reaction is preferably 1 minute or more, more preferably 3 to 10 minutes, still more preferably 1 to 6 minutes, and still more preferably 2 to 5 minutes. By carrying out the reaction under the above conditions, the reaction efficiency can be improved, thereby further improving the performance of the catalyst obtained.

According to the present invention, in the step (2), the contacting is preferably performed by an absorption mixer. Specifically, a twin-shaft paddle type continuous mixer, a single-shaft coulter type continuous mixer, a mixer in which a stirring shaft is provided and an outer cylinder is rotatable, and the like can be used. The coal powder absorbing atomized liquid drops in the double-shaft paddle type continuous mixer is continuously turned, mixed and moved forwards under the turning and extrusion of the double-shaft paddle, so that the atomized liquid drops are continuously and uniformly absorbed. The single-shaft coulter type continuous mixer is characterized in that a rotating shaft is arranged in the single-shaft coulter type continuous mixer, coulter type blades are arranged on the shaft, pulverized coal absorbing atomized liquid drops is driven by the coulter to be strongly stirred and mixed under the driving of quick cutting, and the pulverized coal is gradually pushed to an outlet end to finish discharging. The interior blender that establishes (mixing) shaft and urceolus are rotatable, in this blender, the buggy that has absorbed the atomizing liquid drop is driven by the cutting of inside (mixing) shaft and is mixed by strong stirring, and the wall material that glues under the rotation effect of outside barrel drops and updates, and the material is taken to the eminence by the baffle on the section of thick bamboo wall and is dropped to the exit end under the rotation of outside barrel, realizes continuous controllable ejection of compact. Wherein, the double-shaft paddle type continuous mixer is more beneficial to continuous operation, but the dispersive mixing effect is slightly poor; the single-shaft coulter type continuous mixer has good dispersive mixing effect, but has certain difficulty in continuous operation; the mixer with the stirring shaft inside the barrel and the outer barrel capable of rotating simultaneously has excellent dispersing and mixing effect and is easy to realize continuous operation. Therefore, the absorption mixer is preferably a cylindrical continuous mixer having an agitating shaft therein, and more preferably a cylindrical continuous mixer having an agitating shaft therein and an outer cylinder rotatable.

According to the present invention, in step (1), the moisture content of the semi-dried catalyst is preferably 10 to 30 wt%, more preferably 15 to 28 wt%. By controlling the water content of the semi-dry catalyst to be 20-30 wt%, the coal powder can be kept in a semi-dry flowable state while the high iron loading of the catalyst is realized, and the requirement of continuous conveying is met. When the water content of the semi-dry catalyst is too low, the absorbed iron precipitation slurry is relatively less, the iron loading amount in the catalyst is relatively low, namely the production efficiency of the catalyst is relatively low; when the water content in the semi-dry catalyst is too high, the flow capacity of the semi-dry catalyst is reduced, the phenomenon of wall adhesion and the like occurs, and a mixer and a pipeline are blocked in serious conditions, so that the production is difficult to continue.

According to the present invention, in the step (2), the drying temperature is preferably 80-220 ℃, more preferably 100-. By drying at the temperature, the supported iron active precursor is not decomposed while the catalyst is dried, so that the activity of the catalyst is maintained. In addition, the drying time is preferably 20 to 180 minutes, more preferably 30 to 60 minutes. The drying may be performed using any conventional dryer that can be used for drying a direct coal liquefaction iron-based catalyst, and is preferably performed using a drum dryer through which hot air is introduced.

Through the drying, the iron content of the prepared coal direct liquefaction iron-based catalyst is preferably 3-5.5 wt%, the water content is less than 3 wt%, and the particle size is less than 150 mu m.

The invention also provides the direct coal liquefaction iron catalyst prepared by the preparation method.

The catalyst prepared by the preparation method of the invention has 78-86 wt% of coal powder, 3.0-5.5 wt% of iron, less than 3 wt% of water and 6.9-12.8 wt% of ammonium sulfate, wherein the main component of iron is hydrated oxide FeOOH of iron, the appearance is similar to a rod, the diameter is 40-100nm, and the length is 80-300 nm.

The present invention will be described in detail below by way of examples. The preparation methods used in the following examples are as follows:

as shown in fig. 1, after the ferric salt solution in the ferric salt solution tank 1 and the ammonia-containing solution in the ammonia-containing solution tank 2 are respectively pressurized by the ferric salt solution booster pump 3 and the ammonia-containing solution booster pump 4, the ferric salt solution and the ammonia-containing solution are simultaneously sent into the atomizing nozzle 5 to be mixed and have a rapid precipitation reaction, and are atomized and sprayed from the nozzle to form liquid drops; meanwhile, the coal powder is conveyed into an absorption mixer 6 from a coal powder storage tank 7, the coal powder absorbs sprayed liquid drops in the absorption mixer to form a semi-dry catalyst loaded with iron-containing active ingredients, and the semi-dry catalyst is conveyed into a shoveling plate dryer 9 through a belt conveyor 8. Meanwhile, hot air heated by fuel gas is sent into the inlet of the drying plate 9 from a hot-blast stove 12, semi-dry catalyst is dried until the moisture content of the catalyst product is less than 3 percent and the granularity is less than 150 mu m, and then the catalyst product is collected into a catalyst storage tank 11. Wherein, after the hot air carrying the catalyst fine powder from the tail part of the shoveling plate dryer 9 is purified by a bag dust collector 10, part of the hot air is circulated to the hot blast stove by a tail gas circulator 13, and part of the hot air is discharged.

The catalysts prepared according to the above-mentioned preparation methods by the methods of the following examples and comparative examples on a 100kg/h continuous preparation apparatus and the results of liquefaction of Shendong coal in a 500ml autoclave were shown in Table 1 for the preparation parameters and in Table 2 for the catalyst physical properties and the coal liquefaction results.