Coal direct liquefaction high reactivity feedstock and method for making same

Abstract

The application discloses a kind of coal direct liquefaction high reactivity raw material and its preparation method, the preparation method includes: (1) the solution containing ferrous sulfate and ammonia are sent into fast precipitation reactor, to obtain divalent iron precipitate slurry;Then from the atomization of the nozzle of drying tower is sprayed, forms iron precipitate droplet;(2) iron precipitate droplet is dried in drying tower by hot air, forms hydrated iron oxide solid particle;(3) hydrated iron oxide solid particle enters vacuum belt filter in the bottom of drying tower, uses water spray washing, removes the byproduct ammonium sulfate enriched on the surface of solid particle;(4) after washing, hydrated iron oxide solid particle and washing fine coal particle are together into drying mill and are mixed, grinds and dries, and is made into coal direct liquefaction high reactivity raw material.The application solves the problems that active component of catalyst is easy to aggregate in prior art, mixing and dispersion between active component and reactant coal powder are poor, and industrial catalyst production process is long, and water consumption is large.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of direct coal liquefaction, in particular, to a high reactivity raw material for direct coal liquefaction and a preparation method thereof, more particularly, to a preparation method for efficiently preparing a high reactivity raw material for direct coal liquefaction by integrating the preparation of a raw material coal and a high activity catalyst. BACKGROUND

[0002] The catalyst is the key core technology of direct coal liquefaction. The catalyst can promote the pyrolysis of coal and accelerate the hydrogenation cracking of pyrolysis macromolecules, and improve the yield and quality of oil in the product. Therefore, how to develop and design a catalyst with high catalytic activity, good selectivity and low price has always been a hot spot in the research of direct coal liquefaction. The iron-based catalyst has good activity and low price, and is used in most processes. In some studies, iron ore with large output and low price is used as a catalyst. For example, CN1014418A and CN1298920A disclose a method for using natural high-grade iron ore as a catalyst for direct coal liquefaction. The iron ore is ground into micron-sized particles through multi-stage crushing and grinding and is added to the direct coal liquefaction reaction. In CN1014418A, the iron ore also needs to be pre-reduced, which inevitably increases energy consumption and cost. More researchers tend to synthesize high-activity iron catalysts artificially. For example, CN1231326A discloses a catalyst for direct coal liquefaction using nano-amorphous Fe(OH)3 or Fe(OH)2 as a catalyst, wherein the particle size of the iron-based primary particles is about 30-80 nm, and the catalytic activity is higher than that of natural pyrite. Using coal powder as a carrier to disperse active species is a clever and efficient way to improve the activity of iron catalysts. Using coal powder as a carrier not only allows the precursor iron species to be well dispersed, but also allows the catalytically active components to be in close contact with the reaction raw materials, thereby exerting a better catalytic effect. For example, the world's only industrialized million-ton direct coal liquefaction device built based on the technology of patent CN200410070249.6 uses the catalyst described in patent CN03153377.9, i.e., a high-activity γ-FeOOH catalyst supported on about 1 / 6 of the ground and dried coal powder for liquefaction.

[0003] The existing iron-based catalysts are usually prepared by liquid phase precipitation method, which has a long process flow, is difficult to continuously operate, consumes a large amount of water, generates a large amount of wastewater, and the preparation of the catalyst and the preparation of the coal powder are generally separate, the contact degree between the active components of the catalyst and the coal powder is low, and the energy consumption in the production process is high. Based on the above reasons, the preparation of the catalyst is combined with the preparation of the coal powder, and a preparation method for a high reactivity raw material for direct coal liquefaction is researched to solve the problems of long preparation process, high water consumption and high energy consumption of the existing catalyst preparation process, reduce the production energy consumption, and improve the oil yield of direct coal liquefaction. SUMMARY

[0004] The present application aims to provide a coal direct liquefaction high reactivity raw material and a preparation method thereof, so as to solve the problems in the prior art that the active component of the catalyst is easy to aggregate, the mixing and dispersion between the active component and the reactant coal powder is poor, the industrial catalyst production process is long, the equipment is large, the water consumption is large, and the wastewater discharge is large.

[0005] To achieve the above-mentioned application purpose, one aspect of the present application adopts the following technical scheme:

[0006] A preparation method of a coal direct liquefaction high reactivity raw material, the method comprising the following steps:

[0007] Step (1): a solution containing ferrous sulfate and ammonia water are fed into a rapid precipitation reactor, so that the divalent iron ions are precipitated into divalent iron precipitation slurry by the ammonia water in the rapid precipitation reactor; then the obtained divalent iron precipitation slurry is atomized and sprayed out from the nozzle of a drying tower under the impact of compressed air, forming iron precipitation droplets;

[0008] Step (2): the iron precipitation droplets are dried by hot air in the drying tower, the divalent iron undergoes an oxidation reaction and realizes a crystal phase transition, forming hydrated iron oxide solid particles;

[0009] Step (3): the hydrated iron oxide solid particles enter the vacuum belt filter at the bottom of the drying tower, and at the same time, water spraying washing is adopted to remove the by-product ammonium sulfate enriched on the surface of the hydrated iron oxide solid particles;

[0010] Step (4): the hydrated iron oxide solid particles washed of ammonium sulfate and the washed fine coal particles are mixed and ground together in a drying mill to produce a coal direct liquefaction high reactivity raw material.

[0011] In step (1) of the present application, the solution containing active metals is reacted and precipitated with ammonia water in a rapid precipitation reactor, and then is subjected to spray drying in a drying tower. It can be understood in the art that the solution containing ferrous sulfate can contain other active metal elements that can catalyze direct liquefaction reactions in addition to the active metal element iron; in a preferred embodiment, the solution containing ferrous sulfate is a solution of ferrous sulfate and ammonium heptamolybdate, wherein the molar ratio of iron element to molybdenum element is 40:1 to 300:1, such as 50:1, 100:1 or 200:1.

[0012] In a preferred embodiment, the rapid precipitation reactor in step (1) is a high shear rotor-stator type internal mixing type precipitation reactor, in which the ferrous sulfate solution and the ammonia solution are mixed with high efficiency to form the ferrous precipitate; preferably, the shear rate of the rapid precipitation reactor is 1000-5000 r / min, such as 2000, 3000 or 4000 r / min, which is more conducive to the rapid formation of small crystal iron primary precipitate grains, thereby improving the subsequent coal liquefaction oil yield.

[0013] Preferably, the temperature in the rapid precipitation reactor is controlled at 50-70°C, such as 55, 60 or 65°C; the feed ratio of the ferrous sulfate solution to the ammonia solution is 2:1-6:1, such as 3:1, 4:1 or 5:1, and the appropriate temperature and moderate excess of ammonia are also conducive to the rapid and sufficient formation of the active metal element precipitate.

[0014] In step (1) of the present application, the drying tower is used for rapid oxidation drying of the spray droplets from the spray head, and such spray drying equipment is well known in the art. The drying gas used can be hot air, which will not be described here.

[0015] In a preferred embodiment, the spray head is loaded at the upper center of the drying tower; the diameter of the iron precipitate droplets is less than 2.0 mm, preferably less than 1.0 mm, such as 0.8, 0.5 or 0.2 mm. It is understood in the art that the particle size of the iron precipitate droplets can be controlled by controlling the volume ratio of the compressed air to the iron precipitate slurry (i.e. the ratio of the gas volume to the liquid volume under standard conditions), such as 10:1-100:1, such as 20:1, 30:1, 50:1, 60:1 or 80:1.

[0016] In a preferred embodiment, the concentration of ferrous sulfate in the ferrous sulfate-containing solution in step (1) is 15-30 wt%, such as 20 wt% or 25 wt%, and the concentration of the ammonia solution is 15-30 wt%, such as 20 wt% or 25 wt%; using higher concentration raw materials to prepare coal direct liquefaction iron-based catalysts is conducive to reducing the amount of water used in the precipitation process.

[0017] In step (2) of the present application, the iron precipitation liquid droplets are dried by a drying tower to obtain hydrated iron oxide solid particles; specifically, during drying, the iron precipitation liquid droplets are rapidly oxidized and dried by hot air from the upper part of the drying tower, and can be preliminarily separated from the hot air by the inner member at the bottom of the drying tower when entering the bottom part of the drying tower, and the hot air can be further separated from the entrained solid particles by, for example, a cyclone separation device after leaving the drying tower. In the present application, no coal powder is introduced as a carrier during the precipitation of iron elements and drying, so that the ammonium sulfate easily covers the catalyst active precursor, which is convenient for removal, so that the catalyst is more easily converted to an active phase, and the low-temperature activity is improved; at the same time, the catalyst active precursor is also prevented from being dissolved again to cause loss of active ingredients and adverse effects such as precipitation aging caused by not being oxidized and dried after precipitation and directly being subjected to washing and other treatments.

[0018] In a preferred embodiment, in step (2), the inlet temperature of the hot air into the drying tower is not higher than 180°C, preferably 140-180°C, such as 150, 160 or 170°C, and the residence time of the iron precipitation liquid droplets in the drying tower is 5-30 seconds, such as 8, 10, 20 or 25 seconds, which is beneficial to maintaining a reasonable water content of the dried material.

[0019] In a preferred embodiment, in step (2), the particle size of the dried hydrated iron oxide solid particles is less than 800um, such as 600, 400 or 200um, and the water content is not higher than 25%, and not lower than 10%, such as 12%, 15%, 20% or 22%, and maintaining the reasonable water content is beneficial to making the active ingredient of the catalyst have moderate bonding strength (not to be excessively agglomerated and hardened), the ammonium sulfate can be washed away during washing, and the active ingredient will not be excessively lost, and the hydrated iron oxide solid particles can be easily ground finer and combined with the coal powder more closely during subsequent further grinding and drying with the coal powder.

[0020] In step (3) of the present application, the hydrated iron oxide solid particles are subjected to water spray washing in a vacuum belt filter to remove the by-product ammonium sulfate enriched on the surface of the hydrated iron oxide solid particles. The vacuum belt filter is well known in the art and can also be referred to as a belt vacuum filter, which can quickly filter and remove the washing water. Since the ammonium sulfate is enriched on the surface, the by-product ammonium sulfate can be washed away with only a small amount of water, thereby achieving water saving in the preparation process.

[0021] In a preferred embodiment, in step (3), the amount of water used for water spray washing is 1-3 times, such as 1.5, 2 or 2.5 times, the mass of the hydrated iron oxide solid particles, and the temperature of the water is 15-60°C, such as 20, 30, 40 or 50°C.

[0022] In step (4) of the present application, the washed hydrated iron oxide solid particles and the washed fine coal particles are mixed and ground and dried in a dry mill to be loaded on the surface of the coal powder to produce the coal direct liquefaction high reactivity raw material.

[0023] In some embodiments, in step (4), the dry mill is a drum-type rod mill or a drum-type ball mill, the hydrated iron oxide solid particles and the washed fine coal are fed in parallel with hot nitrogen gas for ball milling and drying; the washed fine coal particles are less than 3 cm; the hot nitrogen gas inlet air temperature is less than 200℃, and the outlet air temperature is 90-105℃.

[0024] To achieve the above-mentioned purpose of the present application, the present application also provides a coal direct liquefaction high reactivity raw material prepared according to the above preparation method; preferably, the coal direct liquefaction high reactivity raw material is composed of a catalyst, dry coal powder, adsorbed water and impurities, wherein the mass percentage of the catalyst is 0.8-1.91% such as 1%, 1.2%, 1.5% or 1.7%; the mass percentage of the dry coal powder is 94-97% such as 95% or 96%, the impurity ammonium sulfate content is less than 0.5% such as 0.2%, 0.3% or 0.4%, and the rest is adsorbed water, the adsorbed water content is less than 4% such as 2% or 3%.

[0025] Preferably, the catalyst comprises a primary active component and a secondary active component, the primary active component is iron element, which exists in the form of FeOOH, and the mass percentage of iron element in the coal direct liquefaction high reactivity raw material is 0.5%-1.2% such as 0.6%, 0.8% or 1.0%; the secondary active component is molybdenum element, which exists in the form of Fe2(M O O4)3, and the mass percentage of molybdenum element in the coal direct liquefaction high reactivity raw material is 0.005-0.05% such as 0.01%, 0.02%, 0.03% or 0.04%.

[0026] In the present application, unless otherwise specified, the percentages or percentage contents involved are mass percentages or mass percentage contents.

[0027] Compared with the prior art, the present application has the following advantages:

[0028] (1) The present application uses a catalyst preparation process combining rapid precipitation reaction with spray drying, rapidly generates small-grained iron primary precipitation grains, and converts to hydrated iron oxide in a very short time to lock the hydrated iron oxide grain size, on the one hand to realize the dispersion of the active components of the catalyst and avoid grain growth, and on the other hand to strengthen the interaction between the active components and the reactant coal powder, so that the coal liquefaction reaction activity is high, the coal liquefaction oil yield is high, and at the same time, the by-product ammonium sulfate is enriched on the surface of the particles, which is convenient for subsequent removal;

[0029] (2) Using high-concentration raw materials to prepare iron-based catalysts for direct coal liquefaction significantly reduces the amount of water used in the precipitation process; at the same time, only a very small amount of water is needed to wash away the byproduct ammonium sulfate, thus achieving significant water savings in the overall catalyst preparation process.

[0030] (3) The catalyst is ground and dried together with the coal powder, which reduces equipment investment and energy consumption. At the same time, the catalyst and the coal powder are in uniform and close contact, which improves catalytic activity and promotes coal conversion.

[0031] (4) It is very convenient to introduce the highly active element molybdenum, and it undergoes a co-precipitation reaction with iron. The two active element solutions produce a synergistic catalytic effect. The catalyst has high activity and is more adaptable to liquefied coal types, especially to coal types that are difficult to liquefy in high inert groups, and it is also adaptable to a wider range of coal liquefaction reaction conditions. Attached Figure Description

[0032] Figure 1 A schematic diagram of a known embodiment of a process apparatus suitable for the preparation method of highly reactive raw materials according to the present invention;

[0033] Explanation of reference numerals in the attached drawings: 1: Ferrous sulfate solution tank; 2: Ammonia solution tank; 3: Iron salt solution metering pump; 4: Ammonia solution metering pump; 5: Rapid precipitation reactor; 6: Nozzle; 7: Drying tower; 8: Cyclone separator; 9: Vacuum belt filter; 10: Drum ball mill dryer; 11: Cyclone separator; 12: Bag filter; 13: Product collection tank. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0035] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and should be understood to include values ​​close to these ranges or values, such as values ​​±10% of the endpoint values. For numerical ranges, endpoint values ​​of various ranges, endpoint values ​​of various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. Without conflict, the embodiments and features described in this application can be combined with each other.

[0036] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0037] The preparation method of the present invention uses a rapid precipitation reactor to rapidly precipitate iron salts to generate an iron-containing precipitate slurry, which is then continuously atomized into small droplets and dried by hot air to form micron-sized solid particles. The by-product ammonium sulfate enriched on the surface of the particles is further washed with water spray, and then crushed and dried together with washed clean coal to produce a highly reactive coal direct liquefaction feedstock.

[0038] like Figure 1 As shown, the high-concentration ferrous sulfate solution in ferrous sulfate solution tank 1 and the high-concentration ammonia solution in ammonia solution tank 2 are pressurized by iron salt solution metering pump 3 and ammonia solution metering pump 4, respectively, and then enter the rapid precipitation reactor 5. A rapid precipitation reaction occurs to generate iron precipitate slurry, which is then conveyed to the nozzle 6 at the top of the drying tower 7. Inside the nozzle, the precipitate is atomized into droplets by compressed air and sprayed downwards. It comes into contact with the hot air from the top of the drying tower in parallel flow, completing the oxidation and drying process, forming dry hydrated iron oxide particles. Large particles fall to the bottom, while small particles enter the cyclone separator 8 with the hot air. After being cycloned, the small particles enter the vacuum belt filter 9 together with the large particles at the bottom of the drying tower. The ammonium sulfate on the surface is washed away by spray water. Then, the particles are conveyed by scraper to the drum ball mill dryer and fed together with coal powder. The drying is completed under the action of hot nitrogen, producing a highly reactive raw material for direct coal liquefaction with a particle size of less than 100 μm and a water content of less than 4%.

[0039] When using the highly reactive coal direct liquefaction feedstock of this invention, the feedstock is first prepared into an oil-coal slurry with a coal direct liquefaction circulating solvent or starting solvent, with a slurry concentration of 40wt% to 50wt%. The oil-coal slurry is pressurized and fed into the coal direct liquefaction reactor, where the coal undergoes pyrolysis and hydrogenation reactions to produce coal liquefaction oil, asphalt, gas, and other products. A certain amount of sulfur powder is added to the oil-coal slurry as an additive, with the amount of sulfur powder added based on an atomic ratio of S to Fe in the feedstock of 1.5 to 2.5. The coal direct liquefaction reaction temperature is 420 to 460°C, the pressure is 10 to 22 MPa, and the residence time is 0.5 to 2 hours.

[0040] The following describes the preparation of highly reactive feedstock for direct coal liquefaction using the production process of the present invention on a continuous preparation device with a capacity of 200 kg / h. The obtained highly reactive feedstock was evaluated in a 500 ml autoclave. The feedstock used was Shendong coal, initially crushed to a depth of less than 3 cm. The results of its industrial analysis, petrographic analysis, and elemental analysis are shown in Table 1. The composition of the highly reactive feedstock for direct coal liquefaction is shown in Table 2, and the coal liquefaction performance results are shown in Table 3.

[0041] Table 1 Property analysis of raw coal

[0042]

[0043] In Table 1, each symbol represents the meaning as follows:

[0044] Proximate analysis part: Mad refers to the air-dried basis water content; Ad refers to the dry basis ash content; Vdaf refers to the dry ash-free basis volatile matter. The method in GB / T211-2017 and GB / T212-2008 is used for determination.

[0045] Elemental analysis part: Fcdaf refers to the dry ash-free basis fixed carbon; C, H, O, N, S respectively refers to the content of each element; The method in GB / T214-2007, GB / T476-2008 and GB / T19227-2008 is used for determination.

[0046] Maceral analysis part: Vitrinite refers to the vitrinite content; Inertinite refers to the inertinite content; Exinite refers to the exinite content. The method in GB / T8899-2013 is used for determination.

[0047] Example 1

[0048] A ferrous sulfate solution with a concentration of 25wt% is prepared, a certain amount of ammonium heptamolybdate is added into the ferrous sulfate solution and dissolved, so that the molar ratio of Mo to Fe in the solution is 2:100; an ammonia solution with a concentration of 30wt% is prepared; the ferrous sulfate solution and the ammonia solution are respectively fed into the rapid precipitation reactor through the metering pump (the volume ratio of the ferrous sulfate solution to the ammonia solution is 3.5:1), the shear speed of the precipitation reactor is adjusted to 3000r / min, the reaction temperature is maintained at 60℃ by adjusting the temperature of the ferrous sulfate solution and the circulating water temperature of the shear head, the volume ratio of the compressed air entering the nozzle to the iron precipitation slurry is controlled to be 30:1, so that the iron precipitation slurry is atomized into droplets smaller than 2.0mm.

[0049] The inlet air temperature of the hot air (air) of the drying tower is controlled to be 150℃, and the residence time is 18 seconds, so that the divalent iron precipitate is dried and oxidized into hydrated iron oxide solid particles (particle size less than 800um, water content about 15%). The ammonium sulfate is washed away on the vacuum belt filter using 2 times the mass of the hydrated iron oxide. The hydrated iron oxide and the coal powder are further mixed in the rotary ball mill at a Fe / dry coal (i.e. the washed clean coal is calculated on a dry basis) mass ratio of 1:100, dried under hot nitrogen gas, and prepared into a high-reactivity coal direct liquefaction raw material, marked as raw material 1#.

[0050] Example 2

[0051] A 25wt% ferrous sulfate solution was prepared, and a certain amount of ammonium heptamolybdate was added to the ferrous sulfate solution and dissolved, so that the molar ratio of Mo to Fe in the solution was 0.5:100; a 30wt% ammonia solution was prepared; the ferrous sulfate solution and the ammonia solution were respectively fed into a rapid precipitation reactor through a metering pump (volume ratio of the ferrous sulfate solution to the ammonia solution was 3.5:1), the shearing speed of the precipitation reactor was adjusted to 3000r / min, the reaction temperature was maintained at 65°C by adjusting the temperature of the ferrous sulfate solution and the circulating water temperature of the shearing head, the volume ratio of compressed air to the iron precipitation slurry entering the nozzle was controlled to be 50:1, so that the iron precipitation slurry was atomized into mist droplets with a size of less than 2.0mm.

[0052] The air inlet temperature of the hot air (air) of the drying tower was controlled to be 170°C, and the residence time was 10 seconds, so that the divalent iron precipitate was dried and oxidized into hydrated iron oxide solid particles (particle size was less than 800um, and the water content was about 12%); the ammonium sulfate was washed away on a vacuum belt filter using 2 times the mass of the hydrated iron oxide; the mass ratio of the hydrated iron oxide to the coal powder entering the drum ball mill was controlled to be 1:100 according to Fe / dry coal (i.e. the washed fine coal was calculated on a dry basis), the hydrated iron oxide and the coal powder were mixed in the drum ball mill, and drying was realized under hot nitrogen gas, so that a high-reactivity coal direct liquefaction raw material was obtained, which was marked as raw material 2#.

[0053] Example 3.

[0054] A 25wt% ferrous sulfate solution was prepared, and a certain amount of ammonium heptamolybdate was added to the ferrous sulfate solution and dissolved, so that the molar ratio of Mo to Fe in the solution was 4:100; a 30wt% ammonia solution was prepared; the ferrous sulfate solution and the ammonia solution were respectively fed into a rapid precipitation reactor through a metering pump (volume ratio of the ferrous sulfate solution to the ammonia solution was 3.5:1), the shearing speed of the precipitation reactor was adjusted to 3000r / min, the reaction temperature was maintained at 65°C by adjusting the temperature of the ferrous sulfate solution and the circulating water temperature of the shearing head; the volume ratio of compressed air to the iron precipitation slurry entering the nozzle was controlled to be 40:1, so that the iron precipitation slurry was atomized into mist droplets with a size of less than 2.0mm.

[0055] The air inlet temperature of the hot air (air) of the drying tower was controlled to be 140°C, and the residence time was 15 seconds, so that the divalent iron precipitate was dried and oxidized into hydrated iron oxide solid particles (particle size was less than 800um, and the water content was about 20%); the ammonium sulfate was washed away on a vacuum belt filter using 2 times the mass of the hydrated iron oxide; the mass ratio of the hydrated iron oxide to the coal powder entering the drum ball mill was controlled to be 0.8:100 according to Fe / dry coal (i.e. the washed fine coal was calculated on a dry basis), the hydrated iron oxide and the coal powder were mixed in the drum ball mill, and drying was realized under hot nitrogen gas, so that a high-reactivity coal direct liquefaction raw material was obtained, which was marked as raw material 3#.

[0056] Example 4

[0057] Except for the ratio of hydrated iron oxide to coal powder into the drum ball mill was controlled as Fe / dry coal 1.2:100, other solution preparation, production process and control conditions were the same as Example 1, and a high reactivity coal direct liquefaction feedstock was obtained, marked as Feedstock 4#.

[0058] Example 5

[0059] Except for the ratio of hydrated iron oxide to coal powder into the drum ball mill was controlled as Fe / dry coal 1.5:100, other solution preparation, production process and control conditions were the same as Example 1, and a high reactivity coal direct liquefaction feedstock was obtained, marked as Feedstock 5#.

[0060] Example 6

[0061] Except for the shear rate in the fast precipitation reactor was adjusted to 5000 r / min, other solution preparation, production process and control conditions were the same as Example 1, and a high reactivity coal direct liquefaction feedstock was obtained, marked as Feedstock 6#.

[0062] Example 7.

[0063] Except for the shear rate in the fast precipitation reactor was adjusted to 500 r / min, other solution preparation, production process and control conditions were the same as Example 1, and a high reactivity coal direct liquefaction feedstock was obtained, marked as Feedstock 6#.

[0064] Example 8

[0065] Except for the reaction temperature in the fast precipitation reactor was controlled to 50°C, other solution preparation, production process and control conditions were the same as Example 1, and a high reactivity coal direct liquefaction feedstock was obtained, marked as Feedstock 8#.

[0066] Example 9

[0067] Except for the reaction temperature in the fast precipitation reactor was controlled to 40°C, other solution preparation, production process and control conditions were the same as Example 1, and a high reactivity coal direct liquefaction feedstock was obtained, marked as Feedstock 9#.

[0068] Example 10

[0069] Except for the gas-liquid ratio of compressed air to iron precipitation slurry into the nozzle was controlled to 60, other solution preparation, production process and control conditions were the same as Example 1, and a high reactivity coal direct liquefaction feedstock was obtained, marked as Feedstock 10#.

[0070] Example 11

[0071] The solution preparation, production process and control conditions are the same as those in Example 1 except that the air-liquid ratio of compressed air to iron precipitate slurry is controlled to be 8 when entering the spray head, and a high-reactivity coal direct liquefaction raw material is obtained, which is marked as raw material 11#.

[0072] Example 12

[0073] The solution preparation, production process and control conditions are the same as those in Example 1 except that the air-liquid ratio of compressed air to iron precipitate slurry is controlled to be 8 when entering the spray head, and a high-reactivity coal direct liquefaction raw material is obtained, which is marked as raw material 11#.

[0074] Comparative Example 1

[0075] First, the coal powder loaded iron catalyst is prepared by liquid phase precipitation oxidation:

[0076] A 8wt% concentration ferrous sulfate solution is prepared, dry coal powder with a particle size of 100 μm or less is added, and the mixture is fully stirred to make Fe / dry coal = 6:100; an ammonia solution with a concentration of 1.8wt% is prepared. The ferrous sulfate and coal powder mixture solution and the ammonia solution are fed in parallel to make ferrous ions precipitate, and then air is introduced for reaction for 1.5h, and the reaction pH value is maintained at 7.5; after the reaction, the mixture slurry is centrifuged to obtain a filter cake, which is washed by adding deionized water, and the washed filter cake is dried in a 110°C nitrogen drying oven for 12h; after drying, the solid is ground to 100 μm or less to obtain a coal powder loaded FeOOH powder catalyst.

[0077] Second, the FeOOH powder catalyst is mixed with a certain amount of coal powder in a V-type mixer to make Fe / dry coal = 1:100. A coal direct liquefaction raw material is prepared, which is marked as comparative raw material 1#.

[0078] Comparative Example 2

[0079] Compared with Example 1, the difference is that the ammonium sulfate is not washed, and the rest is the same as Example 1, and comparative raw material 2# is obtained.

[0080] Catalyst performance evaluation

[0081] A certain amount of coal direct liquefaction raw material prepared in the above examples and comparative examples was weighed and subjected to coal liquefaction autoclave test, and the coal liquefaction reaction performance test conditions were as follows: the coal direct liquefaction raw material in the above examples and comparative examples was accurately weighed and added into a 500 mL autoclave coal liquefaction reaction. The addition amount was 28 g of dry coal; coal liquefaction cycle oil was used as the solvent, the solvent addition amount was 42 g, a certain amount of sulfur powder was added, and the sulfur powder addition ratio was S / Fe atomic ratio. The autoclave reaction cold hydrogen initial pressure was 10 MPa, and the constant temperature was 455°C for 1 h. After the reaction was completed, the reaction system was rapidly cooled, the gas sample was taken for composition test, and the liquid and solid phases after the reaction were collected, which were extracted with n-hexane and tetrahydrofuran for 48 h, and the remaining material was ashed to calculate the coal conversion rate, hydrogen consumption, gas yield, water yield, asphalt yield, and oil yield.

[0082] Table 2 Composition of coal direct liquefaction high reactivity raw material

[0083]

[0084] Table 3 Coal direct liquefaction reaction performance results

[0085]

[0086]

[0087] From the above examples / comparative examples, the coal conversion rate and oil yield of the catalyst prepared by the patent are better than those of the coal powder supported hydrated iron oxide catalyst prepared by the commonly used preparation method in Comparative Example 1, and compared with Example 1, Comparative Example 2 has no washing of ammonium sulfate, and part of the ammonium sulfate covers the active ingredients, causing a decrease in activity; in addition, as compared with Example 1 and Example 7, it can be seen that maintaining the preferred shear rate is beneficial to further improve the conversion rate and oil yield; as compared with Example 1, Example 10, and Example 11, it can be seen that by controlling the preferred volume ratio of compressed air to iron precipitation slurry, the iron precipitation droplet particle size can be controlled, which is beneficial to further improve the conversion rate and oil yield; as compared with Example 1 and Example 12, it can be seen that controlling the preferred hot air drying temperature and controlling the reasonable water content are beneficial to control the iron precipitation droplet particle size, which is beneficial to further improve the oil yield by subsequent combination with coal powder.

Claims

1. A method for preparing a high-reactivity raw material for direct coal liquefaction, the method comprising the following steps: Step (1): feeding a ferrous sulfate-containing solution and ammonia water into a rapid precipitation reactor to obtain a ferrous precipitate slurry; then atomizing and spraying the obtained ferrous precipitate slurry from a nozzle of a drying tower under the impact of compressed air to form ferrous precipitate droplets; wherein the ferrous sulfate-containing solution is a solution of ferrous sulfate and ammonium heptamolybdate, and the molar ratio of iron to molybdenum is 40:1 to 300:1; the nozzle is loaded on the central part of the upper part of the drying tower; the volume ratio of compressed air to ferrous precipitate slurry is 10:1 to 100:1; and the diameter of the ferrous precipitate droplets is less than 2.0 mm; Step (2): drying the ferrous precipitate droplets in the drying tower with hot air, so that the ferrous precipitate is oxidized and the crystal phase is transformed to form hydrated iron oxide solid particles; wherein the inlet temperature of the hot air into the drying tower is not higher than 180℃, and the residence time of the ferrous precipitate droplets in the drying tower is 5 to 30 seconds; Step (3): the hydrated iron oxide solid particles enter a vacuum belt filter at the bottom of the drying tower, and at the same time, water spraying washing is used to remove the byproduct ammonium sulfate enriched on the surface of the hydrated iron oxide solid particles; Step (4): the hydrated iron oxide solid particles washed of ammonium sulfate and washed fine coal particles are mixed and ground together in a drying mill to prepare a high-reactivity raw material for direct coal liquefaction.

2. The production method according to claim 1, characterized by, In step (1), the concentration of ferrous sulfate in the solution is 15 to 30 wt%, and the concentration of ammonia water is 15 to 30 wt%; the temperature in the rapid precipitation reactor is controlled at 50 to 70℃; and the volume ratio of the ferrous sulfate-containing solution to ammonia water is 2:1 to 6:

1.

3. The preparation method according to claim 1, characterized in that, In step (1), the rapid precipitation reactor is a precipitation reactor with a high-speed shearing fixed rotor structure in an internal mixing form, and the ferrous sulfate-containing solution and ammonia water are efficiently dispersed and mixed in the rapid reactor to generate ferrous precipitate.

4. The production method according to claim 3, characterized by, The shearing rate of the rapid precipitation reactor is 1000 to 5000 r / min.

5. The production method according to any one of claims 1 to 4, characterized by, In step (1), the diameter of the ferrous precipitate droplets is less than 1.0 mm.

6. The method of claim 1, wherein, In step (2), the inlet temperature of the hot air into the drying tower is 140 to 170℃.

7. The preparation method according to claim 6, characterized in that, In step (2), the particle size of the dried hydrated iron oxide solid particles is less than 800 um, and the water content is not higher than 25% and not lower than 10%.

8. The production method according to claim 1 or 7, characterized by, In step (3), the amount of water used for water spraying washing is 1 to 3 times the mass of the hydrated iron oxide solid particles, and the temperature of the water is 15 to 60℃.

9. The method of claim 1, wherein, In step (4), the drying mill is a roller-type rod mill or a roller-type ball mill, and the hydrated iron oxide solid particles and washed fine coal are fed in parallel with hot nitrogen gas for ball milling and drying; the particle size of the washed fine coal is less than 3 cm; the inlet temperature of the hot nitrogen gas is less than 200℃, and the outlet temperature is 90 to 105℃.

10. The high-reactivity raw material for direct coal liquefaction prepared by the method according to any one of claims 1 to 9.

11. The coal direct liquefaction high-reactivity feedstock according to claim 10, wherein The coal direct liquefaction high reactivity raw material is composed of a catalyst, dry coal powder, adsorbed water and impurities, wherein the mass percentage of the catalyst is 0.8-1.91%; the mass percentage of the dry coal powder is 94-97%, the content of the impurity ammonium sulfate is less than 0.5%, the rest is adsorbed water, and the content of the adsorbed water is less than 4%; The catalyst comprises a main active component and a secondary active component, the main active component is iron element, which exists in the form of FeOOH, and the mass percentage of the iron element in the high-reactivity raw material for coal direct liquefaction is 0.5-1.2%; the secondary active component is molybdenum element, which exists in the form of Fe2(M O O4)3, and the mass percentage of the molybdenum element in the high-reactivity raw material for coal direct liquefaction is 0.005-0.05%.

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