阅读说明：本技术 一种沸腾床催化剂的级配方法 (Grading method of fluidized bed catalyst ) 是由 吕振辉 朱慧红 金浩 刘璐 杨涛 杨光 于 2019-03-12 设计创作，主要内容包括：本发明公开了一种沸腾床催化剂的级配方法,包括如下内容：重质油原料和氢气从反应器底部进入,与加氢催化剂床层接触进行加氢反应,反应产物由反应器顶部流出；其中所述级配装填至少两级硫化加氢催化剂,各级硫化后的加氢催化剂沿物流方向由下至上,金属活性相片晶平均长度逐级增大、片晶平均层数逐级减少、活性组分含量逐级降低、可几孔径逐级减小,堆积密度逐渐降低,颗粒直径逐渐减小；所述的金属活性相为活性金属硫化物。本发明方法采用特定的催化剂级配能够有效利用催化剂活性中心,提高活性中心结构与反应物分子结构耦合反应性能,大幅提高整个体系加氢反应,如脱金属、脱硫、脱氮等的稳定性,有利于重质油的深度加氢。(The invention discloses a grading method of a boiling bed catalyst, which comprises the following steps: the heavy oil raw material and hydrogen enter from the bottom of the reactor and contact with a hydrogenation catalyst bed layer to carry out hydrogenation reaction, and a reaction product flows out from the top of the reactor; the grading is filled with at least two stages of hydrogenation catalysts for vulcanization, the hydrogenation catalysts after vulcanization at each stage are gradually increased in average crystal length, gradually decreased in average layer number of platelets, gradually decreased in active component content and gradually decreased in pore size from bottom to top along the material flow direction, the bulk density is gradually decreased, and the particle diameter is gradually decreased; the metal active phase is an active metal sulfide. The method of the invention adopts specific catalyst gradation, can effectively utilize the active center of the catalyst, improve the coupling reaction performance of the active center structure and the reactant molecular structure, greatly improve the stability of the hydrogenation reaction of the whole system, such as demetalization, desulfurization, denitrification and the like, and is beneficial to deep hydrogenation of heavy oil.)

1. A method for grading an ebullated-bed catalyst, comprising: the heavy oil raw material and hydrogen enter from the bottom of the reactor and contact with a hydrogenation catalyst bed layer to carry out hydrogenation reaction, and a reaction product flows out from the top of the reactor; the grading is filled with at least two stages of hydrogenation catalysts for vulcanization, the hydrogenation catalysts after vulcanization at each stage are gradually increased in average crystal length, gradually decreased in average layer number of platelets, gradually decreased in active component content and gradually decreased in pore size from bottom to top along the material flow direction, the bulk density is gradually decreased, and the particle diameter is gradually decreased; the metal active phase is an active metal sulfide.

2. The method of claim 1, wherein: the hydrogenation catalyst has the following properties: specific surface area of 100 to 250m²A pore volume of 0.3 to 1.0 mL/g^-1The particle diameter is not less than 5nm, the bulk density is not less than 0.35g/mL, and the particle diameter is 0.1-5.0 mm.

3. The method of claim 1, wherein: the average length of the metal active phase platelets of the sulfidation catalyst at each stage from bottom to top along the material flow direction is increased by 1-5 degrees, preferably 2-4 degrees.

4. The method of claim 1, wherein: the reduction range of the average layer number of the platelets of each stage of the vulcanization catalyst from bottom to top along the material flow direction is 1-5, preferably 2-4.

5. The method of claim 1, wherein: the content of the metal active components of each stage of the vulcanization catalyst is reduced step by step, and the range is 3-15 wt%, preferably 10-15 wt%.

6. The method of claim 1, wherein: the pore diameters of the sulfuration catalysts at all levels can be gradually reduced, and the amplitude is 1-10 nm.

7. The method of claim 1, wherein: the stacking density of each stage of vulcanized catalyst is gradually reduced, and the range is 0.05-0.1 g/mL.

8. The method of claim 1, wherein: the particle diameter of each stage of the vulcanization catalyst is gradually reduced, and the amplitude is 0.1-1.5 mm.

9. The method of claim 1, wherein: the filling proportion of each level of the sulfuration catalyst is at least 10 percent based on the total volume of the catalyst in the reactor.

10. The method of claim 1, wherein: sequentially filling 3-stage vulcanized hydrogenation catalysts, and sequentially filling vulcanized hydrogenation catalysts I, II and III along the material flow direction; wherein the properties of the sulfurized hydrogenation catalyst I are as follows: the aluminum oxide catalyst comprises an aluminum oxide carrier and active metals, wherein the active metals are selected from one or more of VIII group and/or VIB group metal elements; based on the weight of the catalyst, the active metal is calculated by oxide, the VIII group metal is 5.0-9.0 wt%, the VIB group metal is 21-25 wt%, the average number of crystal layers of the active photo is 7.0-9.0, and the average length of the plate crystal is 1.0-3.0 nm; the specific surface area is 50-120 m²(ii)/g, bulk density of 0.55 to 0.85g/mL, particle diameter of 3.5 to 5.0mm, and aperture no less than 15 nm; the properties of the sulfurized hydrogenation catalyst II are as follows: the aluminum oxide catalyst comprises an aluminum oxide carrier and active metals, wherein the active metals are selected from one or more of VIII group and/or VIB group metal elements; based on the weight of the catalyst, the active metal is calculated by oxide, the VIII group metal is 3.0wt% -5.0 wt%, and the VIB group metal is 15wt% -20 wt%; the average number of layers of the active photo is 4.0-6.0, and the average length of the plate crystal is 4.0-6.0 nm; the specific surface area is 150-180 m²(iv)/g, the bulk density is 0.50-0.75 g/mL, the particle diameter is 1.5-3.0 mm, and the diameter of each particle can be 10-15 nm; the properties of the sulfided hydrogenation catalyst III are as follows: the aluminum oxide catalyst comprises an aluminum oxide carrier and active metals, wherein the active metals are selected from one or more of VIII group and/or VIB group metal elements; based on the weight of the catalyst, the active metal is calculated by oxide, and the VIII group metal is 1.0wt% -3.0wt% and VIB group metal is 8wt% -12 wt%; the average number of layers of the active photo is 1.0-3.0, and the average length of the plate crystal is 7.0-9.0 nm; the specific surface area is 190-210 m²(iv)/g, bulk density of 0.40-0.70 g/mL, particle diameter of 0.1-1.0 mm, and optional pore diameter of 5.0-9.0 nm; the hydrogenation catalyst I accounts for 10-90% of the total weight of all the catalysts; the proportion of the hydrogenation catalyst II is 10 to 40 percent; the proportion of the hydrogenation catalyst III is 20-80%.

Technical Field

The invention relates to a grading method of a boiling bed catalyst.

Background

In the heavy oil hydrotreating, the catalyst is generally loaded in a grading way, and the catalyst is generally a protective agent, a demetallization catalyst, a desulfurization catalyst and a denitrification catalyst in sequence. The grading filling of the catalyst can not only increase the scale holding capacity of the catalyst bed layer, but also obviously reduce the pressure drop of the catalyst bed layer. The catalyst grading filling technology can increase the metal capacity of the catalyst system, and because the upstream demetallization catalyst effectively plays a demetallization function, the hydrogenation activity of the downstream high-activity desulfurizer or denitrifier is protected, so the catalyst grading filling technology can increase the hydrogenation capacity of the residual oil hydrotreating catalyst on heavy raw materials.

The reactions in the heavy oil hydrotreating process mainly include hydrodesulfurization, hydrodenitrogenation, hydrodemetallization, aromatics saturation, and hydrocracking of various hydrocarbons. When the heavy raw material enters the reactor, the molecular structure of the reactant is complex, the steric hindrance is large, and impurities are easy to remove; along with hydrogenation and hydrogenolysis reactions, reactant molecules are subjected to ring opening and chain breaking gradually, the molecular structure is simplified gradually, the steric hindrance is small, and impurities are more difficult to remove. The prior heavy oil hydrogenation catalyst grading method is usually researched from the aspect of appearance, namely catalyst particle size, pore channel size, activity transition and the like, and is not considered from the aspect of actual reactant molecular structure, and along with the reaction, the reactant molecular structure and the catalyst structure cannot be well matched, so that the depth of hydrogenation reaction is limited.

CN101942317A discloses a method for grading an ebullated bed catalyst, in which at least two catalysts are used, and under ebullated bed operating conditions, the particle sizes of the catalysts are sequentially reduced along the flow direction of the reaction mass. The method of the invention overcomes the problem that the prior art needs a plurality of fluidized bed reactors or complex internal components are arranged in the fluidized bed reactors to realize different catalyst gradations. The method has the advantages of simple flow, simple reactor structure, high utilization rate of reactor space, stable process operation and high flexibility, and can be used for various heavy oil boiling bed hydrogenation processes.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a grading method of a fluidized bed catalyst, which adopts specific catalyst grading to effectively utilize the active center of the catalyst, improve the coupling reaction performance of the active center structure and the molecular structure of a reactant, greatly improve the stability of hydrogenation reaction of the whole system, such as demetalization, desulfurization, denitrification and the like, and is beneficial to deep hydrogenation of heavy oil.

The grading method of the boiling bed catalyst comprises the following steps: the heavy oil raw material and hydrogen enter from the bottom of the reactor and contact with a hydrogenation catalyst bed layer to carry out hydrogenation reaction, and a reaction product flows out from the top of the reactor; the grading is filled with at least two stages of hydrogenation catalysts for vulcanization, the hydrogenation catalysts after vulcanization at each stage are gradually increased in average crystal length, gradually decreased in average layer number of platelets, gradually decreased in active component content and gradually decreased in pore size from bottom to top along the material flow direction, the bulk density is gradually decreased, and the particle diameter is gradually decreased; the metal active phase is an active metal sulfide.

In the method of the present invention, the heavy oil feedstock is heavy distillate oil such as vacuum wax oil (VGO), coker wax oil (CGO), solvent deasphalted oil (DAO), etc., and Atmospheric Residue (AR), Vacuum Residue (VR), coal tar, coal liquefied oil, etc.

In the method of the present invention, the hydrogenation catalyst (hydrogenation catalyst before sulfidation) is generally a heavy oil hydrogenation catalyst commonly used in the art, such as a hydrogenation protective agent, a hydrodenitrogenation agent, a hydrodemetallization agent, and the like, and generally uses alumina or modified alumina as a carrier, and a group VIII and/or group VIB metal element as an active component, wherein the active metal is calculated by oxide, the group VIII metal is 1wt% to 9wt%, and the group VIB metal is 5wt% to 25wt%, based on the weight of the catalyst.

In the method of the invention, the hydrogenation catalyst has the following properties: specific surface area of 100 to 250m²A pore volume of 0.3 to 1.0 mL/g^-1Has a pore diameter of not less than 5nm and a bulk density of not less than 0.35g/mL, the particle diameter is 0.1-5.0 mm.

In the method, the average length of the metal active phase platelets of each stage of the vulcanization catalyst is 1-9. The average number of layers of metal active phase platelets of each stage of the vulcanization catalyst is 1-9.

In the method, the average length of the metal active phase plate crystals gradually increases by 1-5, preferably 2-4 along the material flow direction from bottom to top.

In the method, the reduction range of the average number of layers of the wafers from bottom to top in the material flow direction is 1-5, preferably 2-4.

In the method, the content of the metal active components of each stage of the vulcanization catalyst is gradually reduced, and the range is 3-15 wt%, preferably 10-15 wt%.

In the method, the pore diameters of the sulfidation catalysts at all levels can be gradually reduced, and the amplitude is 1-10 nm.

In the method, the bulk density of each stage of the vulcanized catalyst is gradually reduced, and the range is 0.05-0.1 g/mL.

In the method, the particle diameter of each stage of the vulcanization catalyst is gradually reduced, and the amplitude is 0.1-1.5 mm.

In the method, the filling proportion of each level of the sulfided catalyst is at least 10 percent based on the total volume of the catalyst in the reactor. Along the material flow direction, when the two-stage filling proportion is: 10% -90%: 10% -90%; the third-level filling proportion is 10% -90%: 10% -40%: 20 to 80 percent; the four-stage filling proportion is as follows: 10% -40%: 10% -40%: 10% -40%: 10 to 40 percent, and the sum of the filling proportions of all levels is 100 percent

In the method, the vulcanization mode can adopt wet vulcanization or dry vulcanization, and the temperature rise speed, the vulcanization temperature and the vulcanization time in the vulcanization process are adjusted according to the required metal active phase platelet structure.

In the method, the hydrogenation catalysts after 3-4 stages of vulcanization are preferably sequentially loaded, and taking the loading of 3 stages as an example, the hydrogenation catalysts I, II and III are sequentially loaded along the material flow direction.

Wherein the properties of the sulfurized hydrogenation catalyst I are as follows: comprises an alumina carrier and an active metal, wherein the active metal is selected from group VIII and/or VIOne or more of B group metal elements; based on the weight of the catalyst, the active metal is calculated by oxide, the VIII group metal is 1wt% -9 wt%, preferably 5.0wt% -9.0 wt%, the VIB group metal is 5wt% -25 wt%, preferably 21wt% -25 wt%, and the balance is an alumina carrier. The average number of layers of the active photo is 7.0-9.0, and the average length of the photo is 1.0-3.0 nm. The specific surface area is 50-120 m²(ii)/g, a bulk density of 0.55 to 0.85g/mL, a particle diameter of 3.5 to 5.0mm, and a pore diameter of not less than 15 nm. The hydrogenation catalyst I can be prepared by using a commercial product or according to the existing method, such as the following method: and supersaturating and dipping the alumina carrier by using a solution containing an active metal component to obtain a catalyst precursor, and drying and roasting to obtain the required hydrogenation catalyst I. The drying temperature is 100-300 ℃, preferably 200-300 ℃, and the drying time is 1-5 h, preferably 4-5 h; the roasting temperature is 700-900 ℃, preferably 750-900 ℃, and the roasting time is 1-5 h, preferably 4-5 h; the heating rate is 2-5 ℃/min.

The preparation method of the vulcanization hydrogenation catalyst I comprises the following steps: filling the catalyst I into a vulcanization reactor, introducing vulcanized oil into the vulcanization reactor, and wetting a catalyst bed layer; then adjusting the temperature of the bed layer to 150-170 ℃, and injecting a vulcanizing agent; after hydrogen sulfide penetrates through the catalyst bed layer, raising the temperature of the catalyst bed layer to 250-270 ℃ at the speed of 2-5 ℃/h, and keeping the temperature for 8-10 hours; and raising the temperature of the catalyst bed to 350-360 ℃ at the speed of 5-10 ℃/h, and keeping the temperature for 8-10 hours.

The sulfuration hydrogenation catalyst II has the following properties: the aluminum oxide catalyst comprises an aluminum oxide carrier and active metals, wherein the active metals are selected from one or more of VIII group and/or VIB group metal elements; based on the weight of the catalyst, the active metal is calculated by oxide, the VIII group metal is 1wt% -9 wt%, preferably 3.0wt% -5.0 wt%, the VIB group metal is 5wt% -25 wt%, preferably 15wt% -20 wt%, and the balance is an alumina carrier. The average number of layers of the active photo is 4.0-6.0, and the average length of the photo is 4.0-6.0 nm. The specific surface area is 150-180 m²(iv) g, bulk density of 0.50-0.75 g/mL, particle diameter of 1.5-3.0 mm, and several pore diameters of 10-15 nm. The hydrogenation catalyst II can be prepared by using a commercial product or according to the existing method, such as the following method: catalyzing the reactionImpregnating the agent carrier with an organic compound solution; heat-treating the obtained organic compound additive-loaded support; and loading the active metal component on the obtained organic matter-loaded carrier to obtain a catalyst precursor, and drying and roasting the catalyst precursor to obtain the required hydrogenation catalyst II. The organic compound may specifically be a compound containing at least two oxygen atom groups and 2 to 5 carbon atoms. In particular compounds containing at least two hydroxyl groups and 2 to 5 carbon atoms. Suitable organic additives include, for example, alcohols, ethers or sugars, for example, suitable alcohols may include ethylene glycol, propylene glycol, glycerol, and the like, suitable ethers may include diethylene glycol, propylene glycol, and the like, and suitable sugars include monosaccharides. One or more of the organic compounds may be selected. The drying temperature is 100-300 ℃, preferably 150-200 ℃, and the drying time is 1-5 h, preferably 2-3 h; the roasting temperature is 400-500 ℃, preferably 450-480 ℃, and the roasting time is 1-5 h, preferably 2-3 h; the temperature rise rate is 5-10 ℃/min. The dosage of the organic compound is 5-10% of the weight of the catalyst carrier.

The preparation method of the vulcanization hydrogenation catalyst II comprises the following steps: filling the hydrogenation catalyst II into a vulcanization reactor, introducing vulcanized oil into the vulcanization reactor, and wetting a catalyst bed layer; then adjusting the temperature of the bed layer to 150-170 ℃, and injecting a vulcanizing agent; after hydrogen sulfide penetrates through the catalyst bed layer, raising the temperature of the catalyst bed layer to 210-230 ℃ at a speed of 5-10 ℃/h, and keeping the temperature for 5-7 hours; and raising the temperature of the catalyst bed to 330-340 ℃ at a speed of 10-15 ℃/h, and keeping the temperature for 5-7 hours.

The sulfuration hydrogenation catalyst III has the following properties: the aluminum oxide catalyst comprises an aluminum oxide carrier and active metals, wherein the active metals are selected from one or more of VIII group and/or VIB group metal elements; based on the weight of the catalyst, the active metal is calculated by oxide, the VIII group metal is 1wt% -9 wt%, preferably 1.0wt% -3.0 wt%, the VIB group metal is 5wt% -25 wt%, preferably 8wt% -12 wt%, and the balance is an alumina carrier. The average number of layers of the active photo is 1.0-3.0, and the average length of the photo is 7.0-9.0 nm. The specific surface area is 190-210 m²(iv)/g, bulk density of 0.40-0.70 g/mL, particle diameter of 0.1-1.0 mm, and optional pore diameter of 5.0-9.0 nm.

The preparation can be carried out by using a commercially available product or according to the existing method, for example, by using the following method: : and (3) saturating and dipping the alumina carrier by using a solution containing an active metal component and an organic compound to obtain a catalyst precursor, and drying to obtain the required hydrogenation catalyst III. The organic compound may specifically be a compound containing at least two oxygen atom groups and 5 to 20 carbon atoms. In particular compounds containing at least two hydroxyl groups and 5 to 20 carbon atoms. Suitable organic additives include, for example, alcohols, ethers or sugars, for example, suitable alcohols may include glycerol and the like, suitable ethers may include triethylene glycol, tributylene glycol or tetraethylene glycol and the like, suitable sugars include polysaccharides, which may include lactose, maltose or sucrose. One or more of the organic compounds may be selected. The drying temperature is 100-300 ℃, preferably 100-150 ℃, and the drying time is 1-5 h, preferably 1-1.5 h; the heating rate is 2-5 ℃/min. The dosage of the organic compound is 15-20% of the weight of the catalyst carrier.

The preparation method of the vulcanization hydrogenation catalyst III comprises the following steps: filling the catalyst into a vulcanization reactor, introducing vulcanized oil into the vulcanization reactor, and wetting a catalyst bed layer; then adjusting the temperature of the bed layer to 150-170 ℃, and injecting a vulcanizing agent; after hydrogen sulfide penetrates through the catalyst bed layer, raising the temperature of the catalyst bed layer to 180-200 ℃ at a speed of 10-15 ℃/h, and keeping the temperature for 2-4 hours; and raising the temperature of the catalyst bed to 310-320 ℃ at a speed of 15-20 ℃/h, and keeping the temperature for 2-4 hours.

The hydrogenation catalyst I accounts for 10-90% of the total weight of all the catalysts; the proportion of the hydrogenation catalyst II is 10 to 40 percent; the proportion of the hydrogenation catalyst III is 20-80%. The filling method of the hydrogenation catalyst grading system generally adopts bag filling or dense phase filling, and is conventional operation in the field.

The catalyst grading process of the present invention can be used under any hydroprocessing conditions suitable in the art. Typical hydrotreating process conditions are: the average reaction temperature is 330-450 ℃, preferably 350-430 ℃; the reaction hydrogen partial pressure is 8.0-20.0 MPa, preferably 10.0-18.0 MPa; liquid hourly volume space velocity of 0.15h^-1～3.0h^-1Preferably 0.2h^-1～2.0h^-1(ii) a The volume ratio of hydrogen to oil is 300-1500, preferably 500-1200.

According to the basic principle of fluidization, the catalyst particles are subjected to mainly gravity, buoyancy and drag forces in the fluidized bed, wherein the density and particle size of the particles determine the stress of the particles, i.e. different particles have different densities and particle sizes, and are subjected to different stresses in the fluidized bed, so that the expansion or suspension height is different. According to the principle, the method uses catalysts with different properties for grading in the fluidized bed reactor, particularly in the heavy oil hydrogenation fluidized bed reactor, realizes an operation method for realizing grading of two or more catalysts in one fluidized bed reactor, and overcomes the problem that the prior art needs to use a plurality of fluidized bed reactors or arrange complex internal components in the fluidized bed reactors to realize grading of different catalysts.

Compared with the prior art, the fluidized bed catalyst grading method provided by the invention has the following advantages:

1. in the method, the catalysts with various active phase structures are graded in sections according to the sizes and the structures of the reactant molecules along the flowing direction of the reactant, so that the coupling reaction of the sizes and the structures of the reactant molecules and the active phase structures is realized, the utilization rate of active metals is improved, and the technical problem that the molecules and the structures of the reactant contradict with the active phase structures is solved.

2. In the method, along the flowing direction of reactants, the reactants which are firstly contacted with the catalyst, such as polycyclic thiophene sulfides, heterocyclic nitrides, polycyclic aromatic hydrocarbon compounds and the like, have more complex structures and larger steric hindrance, and reaction impurities are difficult to remove under the influence of the steric hindrance, so that the metal active photo crystal of the catalyst adopting the method has shorter length and more layers, can obviously reduce the steric hindrance effect, improve the utilization rate of an active phase and ensure that the impurities with larger steric hindrance are easier to remove;

3. in the method, the molecular structure of the reactant is simplified and the steric hindrance is reduced through the preliminary hydrogenation reaction, so that the catalyst adopting the method has moderate metal active photo crystal length and moderate number of layers of the photo crystal, can be coupled with the reaction molecule of the structure more effectively for reaction, and further improves the reaction performance on the reactant molecule;

4. in the method, molecules subjected to final hydrogenation and hydrogenolysis reaction are subjected to ring opening and chain scission to form micromolecular reactants which have simple structures and smaller steric hindrance and are difficult to react, such as thiophene sulfides, monocyclic nitrides and monocyclic, bicyclic or tricyclic aromatic compounds, and finally the catalyst adopting the method has longer metal active photo crystal length and fewer layers of the photo crystal, further performs hydrogenation reaction on the micromolecules with smaller steric hindrance to remove impurities contained in the micromolecules which are difficult to remove, improves the utilization rate of active metals, and realizes effective reaction on reactant molecules;

5. the preparation method and the grading technology of the fluidized bed catalyst adopted in the method can obviously improve the utilization rate of active metal of the catalyst in the fluidized bed reactor, and improve the demetalization, desulfurization and other performances of the system.

Drawings

FIG. 1 is a TEM spectrum of the sulfided state of catalyst I in example 1 of the present invention.

FIG. 2 is a TEM spectrum of the sulfided state of catalyst II in example 1 of the present invention.

FIG. 3 is a TEM spectrum of the sulfided state of catalyst III in example 1 of the present invention.

Detailed Description

The preparation and grading process of the hydrogenation catalyst of the present invention is described in more detail below by way of specific examples. The examples are merely illustrative of specific embodiments of the process of the present invention and do not limit the scope of the invention. In the method, the length and the number of layers of the catalyst are statistically analyzed by a Transmission Electron Microscope (TEM); the pore structure of the catalyst is determined by nitrogen adsorption-desorption. The carrier I used in the examples and comparative examples is an alumina carrier having a specific surface area of 140 to 160m²(iv)/g, the aperture of each particle is 18-21 nm, the bulk density is 0.35-0.40 g/mL, and the particle diameter is 3.5-5.0 mm; the carrier II is an alumina carrier with the specific surface area of 170～190m²(iv) per g, the aperture can be 15-17 nm, the bulk density is 0.41-0.50 g/mL, and the particle diameter is 1.5-3.0 mm; the carrier III is an alumina carrier, and the specific surface area of the carrier III is 200-300 m²The particle diameter of the particles is 5-9 nm, the bulk density is 0.51-0.62 g/mL, and the particle diameter is 0.1-1.0 mm.