CN1277611C - Tungsten carbide catalyst and its preparation method and special retort - Google Patents
Tungsten carbide catalyst and its preparation method and special retort Download PDFInfo
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- CN1277611C CN1277611C CN 200410067120 CN200410067120A CN1277611C CN 1277611 C CN1277611 C CN 1277611C CN 200410067120 CN200410067120 CN 200410067120 CN 200410067120 A CN200410067120 A CN 200410067120A CN 1277611 C CN1277611 C CN 1277611C
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- 239000003054 catalyst Substances 0.000 title claims abstract description 50
- 238000002360 preparation method Methods 0.000 title claims abstract description 20
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- 239000007921 spray Substances 0.000 claims abstract description 10
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- 239000007864 aqueous solution Substances 0.000 claims abstract description 5
- 239000000463 material Substances 0.000 claims description 37
- 238000003763 carbonization Methods 0.000 claims description 36
- 238000000034 method Methods 0.000 claims description 26
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 23
- 238000010791 quenching Methods 0.000 claims description 14
- 230000008569 process Effects 0.000 claims description 13
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 12
- 229910002091 carbon monoxide Inorganic materials 0.000 claims description 12
- 230000000171 quenching effect Effects 0.000 claims description 12
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 11
- 239000001569 carbon dioxide Substances 0.000 claims description 11
- 230000009467 reduction Effects 0.000 claims description 11
- 229910052751 metal Inorganic materials 0.000 claims description 9
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- 229910052799 carbon Inorganic materials 0.000 claims description 4
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- 239000011449 brick Substances 0.000 claims description 3
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 2
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- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 abstract description 6
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- 238000002161 passivation Methods 0.000 description 4
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- 238000001035 drying Methods 0.000 description 3
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- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- -1 ammonium hydroxide ions Chemical class 0.000 description 2
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- OAXLZNWUNMCZSO-UHFFFAOYSA-N methanidylidynetungsten Chemical compound [W]#[C-] OAXLZNWUNMCZSO-UHFFFAOYSA-N 0.000 description 2
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- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical group [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
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- ZOMNIUBKTOKEHS-UHFFFAOYSA-L dimercury dichloride Chemical class Cl[Hg][Hg]Cl ZOMNIUBKTOKEHS-UHFFFAOYSA-L 0.000 description 1
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Abstract
The present invention relates to a wolfram carbide catalyst, a preparation method thereof, and special equipment thereof. The wolfram carbide catalyst of the present invention is a spherical particle with a mesopore structure. The present invention has the preparation process that ammonium metatungstate as raw material is dissolved in water, the mixture is uniformly mixed sufficiently, 10 to 30% of aqueous solution is prepared, the solution is led into a spray dryer to carry out spray drying, and H2WO3 particle precursors are obtained; then, the obtained H2WO3 particle precursors are roasted, reducing and carburizing reaction is carried out on the roasted H2WO3 particle precursors, products are rapidly cooled in the air isolating environment after the reaction finishes, and the spherical wolfram carbide catalyst with a mesopore structure is obtained by separation. The present invention uses feed stock selection, precursor construction and pattern control, preparation process parameter control and construction pattern control of the final products in the process for preparing the wolfram carbide catalyst as a whole. The prepared wolfram carbide catalyst has large specific surface area and high catalytic activity.
Description
(I) technical field
The invention relates to a tungsten carbide catalyst, a preparation method and special equipment thereof, in particular to a hollow spherical tungsten carbide catalyst with a mesoporous structure.
(II) background of the invention
Tungsten carbide generally refers to the generic name of tungsten carbide, and tungsten carbide as a catalyst is mainly tungsten monocarbide (WC) and ditungsten monocarbide (W)2C)。
The existing tungsten carbide preparation methods are various and mainly comprise gas phase reaction, gas-solid reaction, solid phase exchange reaction, liquid phase reaction and the like. The tungsten carbide catalyst prepared by the method is mostly WC and W2The mixture of C has the problems of small specific surface area, poor catalytic activity, complex system, low efficiency, high production cost, difficult control of process conditions and the like, and is difficult to implement in practical application.
The structure and the appearance of a sample prepared by the existing method are both granular or solid spherical, and no report related to the mesoporous structure hollow spherical tungsten carbide and the preparation method thereof exists.
The existing preparation method usually pays much attention to the control of preparation process conditions or the control of the morphology and structure of tungsten carbide catalyst particles or the selection of raw materials, and does not consider the factors in the aspects as an organic whole which is mutually connected, particularly the control of the structure and the morphology of a tungsten carbide catalyst intermediate. For example, chinese patent CN86106868A discloses a method for producing a tungsten carbide catalyst and a special device thereof, which only relates to the control of preparation process parameters and the control of the structure and morphology of the final product, so that the tungsten carbide catalyst with a mesoporous structure cannot be prepared.
The key point of further improving the catalytic activity of the tungsten carbide is to increase the specific surface area of the tungsten carbide; the tungsten carbide catalytic performance mainly depends on the morphology and structural characteristics of particles, and the morphology and structural characteristics of tungsten carbide catalyst particles are closely related to those of a precursor; the preparation process conditions have certain influence and restriction on the specific surface area ofthe tungsten carbide, but the problem of improvement of the catalytic performance of the tungsten carbide cannot be fundamentally solved; in order to improve the catalytic performance of the tungsten carbide catalyst, attention is paid not only to the preparation process conditions, but also to the control and treatment of the structure and morphological characteristics of the precursor.
Disclosure of the invention
Aiming at the defects of the prior art, the invention considers the four main steps of raw material selection, intermediate structure and appearance control, preparation process parameter control and final product structure and appearance control in the tungsten carbide catalyst preparation process as an organic whole body which is mutually influenced, and provides the hollow spherical tungsten carbide catalyst with the mesoporous structure, which has large specific surface area and high catalytic activity.
The invention also aims to provide a preparation method and special equipment for preparing the tungsten carbide catalyst.
The tungsten carbide catalyst of the invention is in the shape of mesoporous structure hollow spherical particles, and the preparation method comprises the following steps: firstly dissolving an ammonium metatungstate raw material in water, fully and uniformly mixing to prepare a solution with the weight concentration of 10-30%, and then introducing the solution into a spray dryer for spray drying to obtain H2WO3A particulate precursor; then the obtained H is2WO3Baking decomposition, reduction carbonization reaction of the particle precursor, and air-isolated ring after the reactionAnd (3) quenching the product, and separating to obtain the mesoporous-structure hollow spherical tungsten carbide catalyst.
Specifically, the mesoporous structure hollow spherical tungsten carbide catalyst is prepared by the following steps:
(A) dissolving an ammonium metatungstate raw material in water, and fully and uniformly mixing to prepare an aqueous solution with the weight concentration of 10-30%;
(B) introducing the solution prepared in the step (A) into a spray dryer for spray drying to obtain H2WO3GranuleA pellet precursor;
(C) subjecting H obtained in step (B) to2WO3The particle precursor is roasted and then subjected to reduction carbonization reaction, and after the reaction is finished, the product is quenched in an air-isolated environment to prepare the mesoporous-structure hollow spherical tungsten carbide catalyst.
The quenching treatment is to rapidly reduce the temperature of the generated tungsten carbide product from hundreds of degrees to below room temperature, so that the shape of the mesoporous hollow spherical particles is preserved.
The mesoporous-structure hollow spherical tungsten carbide catalyst is preferably prepared by the following steps:
(A) dissolving ammonium metatungstate in water to prepare a solution with the weight concentration of 15-20%, and oscillating for 20-60 minutes by using ultrasonic waves at room temperature;
(B) introducing the solution into a spray dryer for spray drying while stirring with a magnetic stirrer to obtain H2WO3A particulate precursor;
(C) taking a mixed gas of carbon monoxide and carbon dioxide as a reducing gas and a carbon source, and obtaining H in the step (B)2WO3Roasting and reducing carbonization reaction of the particle precursor, introducing the product into an ice water bath under the condition of air isolation for quenching treatment after the reaction is finished, and separating to obtain dark gray slurry, namely the tungsten carbide catalyst;
the volume ratio of the carbon monoxide to the carbon dioxide is 7-15: 1, the preferred ratio is 8-12: 1, the most preferred ratio is 10: 1, and the flow speed of the mixed gas is 0.25-0.55 m.s-1；
The roasting temperature is 450-550 ℃, preferably 500 ℃, and the roasting time is 0.5-5 hours, preferably 2.5-3.5 hours, and most preferably 3 hours.
The reduction carbonization reaction temperature is 550-800 ℃, preferably 700-800 ℃, most preferably 750 ℃, and the time is 10-15 hours, preferably 12-13 hours.
During the dissolution process, ammonium metatungstate dissolves in water to form ammonium hydroxide ions and metatungstic acid:
the purpose of the spray drying is to dry the aqueous ammonium metatungstate solution to form H2WO3A particulate precursor, and a precursor H is completed2WO3Granulation, structure and morphology control. Spray dried precursor H2WO3The particle size, structure and morphology of (a) are shown in fig. 3. FIG. 3a is the overall morphology of the sample after spray drying, from which precursor H can be seen2WO3Spherical particles with different sizes are adopted; spherical particles have a hollow structure as shown in fig. 3 b.
The preferable technological conditions of the spray drying process are as follows: the inlet flow rate of the ammonium metatungstate solution is 15ml/min, and the air inlet flow rate is 35m3The inlet temperature of the hot air nozzle was 165 ℃ and the temperature of the offgas outlet was 105 ℃.
In the spray drying process, the ammonium hydrate ions are decomposed to generate water vapor and ammonia gas, the water vapor and the ammonia gas flow out of the spray dryer along with hot air in a solvent, and the spray-dried powder is a metatungstic acid precursor containing certain moisture.
In the roasting process, the precursor H is mainly2WO3And (4) dehydrating. Firstly removing the adsorbed water, then removing the crystal water, and then removing the structural water to finally generate the WO3。
During the reduction and carbonization reaction, WO3The reduction reaction is carried out under the action of CO to gradually reduce the product into WO2And W; at the same time, CO undergoes self-reduction reaction to generate C and CO2: c generated by CO self-reduction reaction is adsorbed to the surface of metal W reduced by CO, and C is expanded under high temperatureThe dispersion effect enters the interior of metal W, and forms a mesoporous structure hollow spherical WC with tungsten atoms, and the reaction processes are respectively as follows:
once the mesoporous spherical structure is formed, if a certain technology and method are not adopted for protection, the structure is easy to be damaged, and therefore, the mesoporous spherical structure is protected and stored by adopting a quenching technology and oxygen in water.Quenching usually refers to rapid cooling at room temperature or below, and the specific method is that after reduction and carbonization are completed, the generated product is rapidly put into ice water, so that the temperature of the product is rapidly reduced from hundreds of degrees to below room temperature (20 ℃), thereby avoiding the damage of diffusion effect of the product in the slow temperature reduction process to the mesoporous structure, and effectively preserving the structure and the appearance of the tungsten carbide particles. The tungsten carbide catalyst has high activity and is easy to generate spontaneous combustion and oxidation in air. It is therefore necessary to passivate the surface by a certain technique. During the quenching process, trace oxygen contained in the ice water can be adsorbed to the surface of the tungsten carbide, so that the activity of the tungsten carbide is reduced, and the purpose of passivation is achieved.
The T-shaped carbonization furnace used for preparing the tungsten carbide catalyst comprises a shell, a T-shaped reaction tube, a receiving water tank and a material boat for placing reactants, wherein the T-shaped reaction tube comprises a gas pretreatment section, a reaction section and a discharging tube, and a metal filler is filled in the gas pretreatment section and is externally connected with a gas inlet; the blanking pipe is connected with the expanding pipe in a downward connection mode, the expanding pipe is inserted into the material receiving water tank, the bottom of the material receiving water tank is connected with the tungsten carbide outlet, the shell is composed of a low-temperature section and a high-temperature section, and the length of the low-temperature section is 1-5 times that of the material boat, preferably 3 times that of the material boat; the length of the high-temperature section is 10-15 times of the length of the material boat, and preferably 12 times of the length of the material boat.
The shell is lined with refractory bricks and heat insulation materials, a heating element is laid, and a temperature measuring thermocouple and a temperature control system are arranged; the T-shaped reaction tube is welded by heat-resistant steel, the blanking tube is positioned between the gas pretreatment section and the reaction section and is in an asymmetric inverted cone shape, the lower end of the blanking tube is connected with an expanding tube through a detachable flange, the expanding tube is inserted into the blanking tube to ensure that the blanking tube is kept in a liquid seal, the blanking tube is welded by a polyvinyl chloride plate and is in a funnel shape, and the lower part of the blanking tube is connected with a glass fiber reinforced plastic discharge valve.
After entering the carbonization furnace from the inlet of the material boat, the sample is firstly roasted and decomposed in the low-temperature section of the carbonization furnace and then enters the high-temperature section of the carbonization furnace for reduction carburization reaction. In the gas pretreatment stage, the carbon monoxide and carbon dioxide are preheated by contact with the metal packing and impurities are removed therefrom. The metal filler is copper scraps or iron scraps.
The tungsten carbide catalyst provided by the invention can work according to the following process:
3 material boats are placed in the low temperature section of the T-shaped carbonization furnace, 12 material boats are placed in the high temperature section, and one material boat is pushed in from an inlet every 1 hour to ensure that the material boats stay for 2 hours in the low temperature section of the T-shaped carbonization furnace and stay for more than 12 hours in the high temperature section, but not more than 13 hours. With the pushing of a material boat from the inlet 11 every 1 hour, at the other end of the T-shaped reaction tube, a material boat which stays for 12 hours in the high-temperature section of the carbonization furnace is necessarily slid into the material quenching tank, so that the reaction product is rapidly quenched to keep the original structure and appearance. The temperature of the quench liquid in the quench tank is below room temperature.
The preparation technology of the tungsten carbide catalyst has the following advantages:
1. drying, granulating, and controlling the shape and structure of the precursor. The advantages of the ultrasonic technology and the spray drying technology are fully utilized, the ultrasonic technology and the spray drying technology are organically combined, and the method is applied to drying and granulating of precursors and controlling of shapes and structures.
2. And forming and controlling a mesoporous spherical structure. Due to the precursor H2WO3Contains a certain amount of water, and part of water molecules and WO are mixed in the process of roasting, decomposing and dewatering3Combined to form WO2(OH)2And volatilizing. With W in WO2(OH)2The form of the mesoporous structure is lost, and the morphology and the structure of the intermediate are changed, so that the mesoporous structure is formed.
3. And (4) protecting and preserving the mesoporous spherical structure. Once the mesoporous spherical structure is formed, it is easily damaged if it is not protected by a certain technique and stored. Therefore, the tungsten carbide particles are protected and stored by adopting a quenching technology, so that the damage of the diffusion effect of the product in the slow cooling process to the mesoporous structure is avoided, and the structure and the appearance of the tungsten carbide particlesformed in the reduction carbonization process are stored.
4. The technology of precursor drying, granulation, morphology and structure control and the technology of mesoporous spherical structure formation, control, protection and preservation are organically combined.
5. Passivation of tungsten carbide catalyst. The passivation technology of the tungsten carbide and the protection and preservation technology of the structure and the appearance of the tungsten carbide are organically combined, and the surface of the tungsten carbide is passivated while quenching is carried out. This is because trace oxygen contained in the ice water is adsorbed to the surface of the tungsten carbide during the quenching process, thereby reducing the activity thereof and achieving the purpose of passivation.
(IV) description of the drawings
FIG. 1 is a process flow diagram for preparing a tungsten carbide catalyst according to the present invention.
FIG. 2 is a schematic structural view of a T-shaped carbonization furnace according to the present invention.
FIG. 3 is H according to the present invention2WO3Scanning electron micrographs of the particulate precursor, where a is magnified 1,000 times and b is magnified 10,000 times.
FIG. 4 is a scanning electron micrograph of a tungsten carbide catalyst prepared in example 1, wherein a is magnified 1,500 times, b is magnified 7,000 times as much as the portion shown in the box of a, and c and d are magnified 50,000 times as much as each of the different positions of the catalyst.
Fig. 5 is a steady state polarization plot for the gas diffusion electrodes prepared in examples 2 and 3.
(V) detailed description of the preferred embodiments
The present invention is further illustrated by the following examples, which should not be construed as limiting the scope of the invention.
Example 1
Referring to fig. 2, the T-shaped carbonization furnace comprises a shell, a T-shaped reaction tube, a receiving water tank 1 and a material boat 2 for placing reactants. The T-shaped reaction tube is welded by heat-resistant steel and comprises a gas pretreatment section 3, a reaction section 4 and a blanking tube 5, wherein the gas pretreatment section 3 is filled with a metal filler 6 and is externally connected with a gas inlet 7; the blanking pipe 5 is positioned between the gas pretreatment section 3 and the reaction section 4, the blanking pipe 5 is connected with the expanding pipe 8 in a downward mode, and the expanding pipe 8 is inserted into the material receiving water tank 1; the receiving water tank 1 is welded by a polyvinyl chloride plate and is funnel-shaped, and the bottom of the receiving water tank is connected with a tungsten carbide outlet 9; the reaction section 4 is connected with a gas outlet 10 after reaction and a material boat inlet cock 11. The shell consists of a low-temperature section 12 and a high-temperature section 13, wherein the length of the low-temperature section 12 is 3 times that of the material boat 3, and the length of the high-temperature section 13 is 12 times that of the material boat 3. The low temperature section, the high temperature section and the gas pretreatment section are all independently connected with a temperature controller 14. The shell is lined with refractory bricks and insulation and houses the heating elements.
Dissolving ammonium metatungstate in water to prepare a 20% solution, andoscillating for 30 minutes by ultrasonic waves at room temperature; introducing the solution into a spray drier while stirring with a magnetic stirrer for spray drying to obtain H2WO3Particles; the dried intermediate is loaded into a material boat 2, and simultaneously, the switches of the carbon monoxide and carbon dioxide gas cylinders are opened, the mass flow of the carbon monoxide and carbon dioxide gas cylinders is controlled by a gas mass flowmeter, the mass ratio of the carbon monoxide and the carbon dioxide gas entering a gas mixing device is 10: 1, and the gas flow rate is 0.45mS-1And then enters a T-shaped carbonization furnace through a gas mixing device. After the mixed gas enters the T-shaped carbonization furnace, the mixed gas is preheated by the iron filings and metal fillers 6 filled in the pretreatment section 3 and harmful impurities are removed, then the mixed gas enters the high-temperature section 13 to react with the intermediate reversely pushed by the intermediate inlet cock, then the mixed gas passes the low-temperature section 12, and finally the gas is discharged from the gas outlet 10 after the reaction. The temperature of the high temperature section 13 of the T-shaped carbonization furnace is raised to 800 ℃ and stabilizedThe temperature of the low temperature section 12 of the T-shaped carbonization furnace was set at 800 ℃ and at the same time, the temperature was raised to 500 ℃ and stabilized at 500 ℃. The above state was maintained for 30 minutes to remove air from the inside of the production apparatus. After the temperature in the carbonization furnace is stabilized, under the condition that the gas flow rate and the flow are kept unchanged, the material boat 2 filled with the intermediate is pushed into the low-temperature section 12 of the carbonization furnace from the material boat inlet 15 and the intermediate inlet cock 11 of the T-shaped carbonization furnace to be roasted, one material boat is pushed in every 1 hour, so that the intermediate enters the high-temperature section 13 from the low-temperature section 12 after being roasted for 3 hours to be reduced and carbonized, the number of the material boats filled with the intermediate entering the high-temperature section 13 of the carbonization furnace is continuously increased along with the continuous pushing of the material boats filled with the intermediate, and after 15 hours, the number of the material boats filled with the intermediate in the high-temperature section 13 of the carbonization furnace reaches saturation, namely 12. After that, while pushing in one boat containing the intermediate every hour, there is necessarily another boat containing the intermediate which has been reduced and carbonized in the high temperature stage for more than 12 hoursAt the same time of the boat, another material boat which is reduced and carbonized for more than 12 hours in the high-temperature section and is filled with reaction products is necessarily slid into the material receiving water tank 1 from the discharging pipe 5 of the carbonization furnace, the temperature is rapidly reduced under the action of ice water, and the dark gray slurry is obtained through separation, namely the mesoporous structure hollow spherical tungsten carbide catalyst. The prepared tungsten carbide catalyst is analyzed by a scanning electron microscope, and as can be seen from figure 4, the obtained tungsten carbide catalyst is in a mesoporous structure hollow sphere shape.
Example 2
The mesoporous tungsten carbide catalyst prepared in example 1 was used to prepare a gas diffusion electrode, and the catalytic activity of the gas diffusion electrode was tested by a polarization curve method, and the results are shown in fig. 5 b. The instrument is a microcomputer-controlled CHI620B electrochemical analyzer, a three-electrode testing system is adopted in the experiment, and the electrolyte is H2SO4(2mol/dm3) The reference electrode is a saturated calomel electrode, the counter electrode is a Pt sheet, the experimental temperature is 25 +/-1 ℃, the hydrogen flow rate is 100ml/min, and the scanning speed is 0.5 mv/min.
Comparative example 1
The test procedure described in example 2 was repeated using a gas diffusion electrode made from plain particulate tungsten carbide, and the results are shown in the graph of figure 5 a.
From fig. 5, it can be found that the electrode using the mesoporous hollow spherical tungsten carbide as the catalyst has a high absolute value of current. This shows that the electrode body using the mesoporous hollow spherical tungsten carbide as the electrocatalyst has higher electrocatalytic activity under the same reaction conditions.
Claims (10)
1. A tungsten carbide catalyst is characterized in that the morphology of the catalyst is mesoporous structure hollow spherical particles, and the preparation method comprises the following steps: dissolving an ammonium metatungstate raw material in water, fully and uniformly mixing to prepare a solution with the weight concentration of 10-30%, and then introducing the solution into a spray dryer for spray drying to obtain H2WO3A particulate precursor; then the obtained H is2WO3Roasting and reducing carbonization of the particle precursor, quenching the product in air isolating environment after the reaction, and separating to obtain the mesoporous hollow spherical tungsten carbide catalyst.
2. A method of preparing the tungsten carbide catalyst according to claim 1, comprising the steps of:
(A) dissolving an ammonium metatungstate rawmaterial in water, and fully and uniformly mixing to prepare an aqueous solution with the weight concentration of 10-30%;
(B) introducing the solution prepared in the step (A) into a spray dryer for spray drying to obtain H2WO3A particulate precursor;
(C) subjecting H obtained in step (B) to2WO3The particles are roasted and then subjected to reduction carbonization reaction, and after the reaction is finished, the product is quenched in an air-isolated environment to prepare the mesoporous-structure hollow spherical tungsten carbide catalyst.
3. The method for preparing a tungsten carbide catalyst according to claim 2, characterized by comprising the steps of:
(A) dissolving an ammonium metatungstate raw material in water to prepare an aqueous solution with the weight concentration of 15-20%, and oscillating for 20-60 minutes by using ultrasonic waves at room temperature;
(B) introducing the solution into a spray dryer for spray drying while stirring with a magnetic stirrer to obtain H2WO3A particulate precursor;
(C) using the mixed gas of carbon monoxide and carbon dioxide as reducing gas and carbon source, and carrying out the step (B)Obtained H2WO3Roasting and reducing carbonization reaction of the particle precursor, introducing the product into an ice water bath under the condition of air isolation for quenching treatment after the reaction is finished, and separating to obtain dark gray slurry, namely the tungsten carbide catalyst;
the volume ratio of the carbon monoxide to the carbon dioxide is 7-15: 1, and the flow speed of the mixed gas is 0.25-0.55 m.s-1；
The roasting temperature is 450-550 ℃, and the time is 0.5-5 hours;
the reduction carbonization reaction temperature is 550-800 ℃, and the time is 10-15 hours.
4. The preparation method of the tungsten carbide catalyst according to claim 3, wherein the volume ratio of carbon monoxide to carbon dioxide is 8-12: 1, the roasting time is 2.5-3.5 hours, and the reduction carbonization reaction time is 12-13 hours.
5. The method of claim 3, wherein the carbon monoxide and carbon dioxide are preheated by contacting with the metal filler and removing impurities therefrom.
6. The method for preparing a tungsten carbide catalyst according to any one of claims 2 to 5, wherein the inlet flow rate of the aqueous solution of ammonium metatungstate is 15ml/min and the inlet flow rate of air is 35m during the spray drying process3The inlet temperature of the hot air nozzle was 165 ℃ and the temperature of the offgas outlet was 105 ℃.
7. The method for preparing a tungsten carbide catalyst according to claim 5, wherein the volume ratio of carbon monoxide to carbon dioxide is 10: 1; the roasting temperature is 500 ℃, and the time is 3 hours; the reduction carbonization reaction temperature is 750 ℃, and the time is 12-13 hours.
8. The T-shaped carbonization furnace used for preparing the tungsten carbide catalyst of claim 1, which comprises a shell, a T-shaped reaction tube, a material receiving water tank and a material boat for placing reactants, wherein the T-shaped reaction tube comprises a gas pretreatment section, a reaction section and a discharging tube, the gas pretreatment section is filled with metal filler and is externally connected with a gas inlet; the unloading pipe connects down and expands the venturi tube, expands the venturi tube and inserts the material water lees, and tungsten carbide export, its characterized in that are connected to the material water lees bottom: the shell consists of a low-temperature section and a high-temperature section, wherein the length of the low-temperature section is 1-5 times that of the material boat, and the length of the high-temperature section is 10-15 times that of the material boat.
9. A T-shaped carbonization furnace as claimed in claim 8, characterized in that the casing is lined with refractory bricks and insulation and is provided with heating elements; the T-shaped reaction tube is welded by heat-resistant steel, the blanking tube is positioned between the gas pretreatment section and the reaction section and is in an asymmetric inverted cone shape, the lower end of the blanking tube is connected with the expanding tube through a detachable flange, the receiving water tank is welded by a polyvinyl chloride plate and is in a funnel shape, and the lower part of the receiving water tank is connected with a glass fiber reinforced plastic discharge valve.
10. The T-shaped carbonization furnace as claimed in claim 8 or 9, characterized in that the length of the low-temperature section is 3 times the length of the material boat, and the length of the high-temperature section is 12 times the length of the material boat.
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| CN100547114C (en) * | 2007-05-25 | 2009-10-07 | 浙江工业大学 | A kind of on the metallic surface method of fusing and coating high-hardness tungsten carbide coat |
| CN100493709C (en) * | 2007-09-30 | 2009-06-03 | 浙江工业大学 | Carbon tube carried nano-tungsten carbide catalyzer and method of preparing the same |
| CN101576345B (en) * | 2009-06-15 | 2011-06-29 | 株洲硬质合金集团有限公司 | Parallel connection buffer type hydrogen-free carbonized carbon tube furnace system and production process thereof |
| CN101671019B (en) * | 2009-09-29 | 2011-06-29 | 浙江工业大学 | Method for preparing mesoporous needle-shaped tungsten carbide |
| CN103357408B (en) | 2012-03-31 | 2015-06-17 | 浙江工业大学 | WC/CNT (wolfram carbide/carbon nano-tube), WC/CNT/Pt (wolfram carbide/carbon nano-tube/platinum) composite materials and preparation method and application thereof |
| CN106430209B (en) * | 2016-09-19 | 2019-02-12 | 中冶东方工程技术有限公司 | The preparation method and product of meso-porous nano tungsten carbide |
| CN110512108A (en) * | 2019-09-12 | 2019-11-29 | 骆佳晨 | It is a kind of based on penetrate inhale principle novel molybdenum wire carbonized furnace |
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