CN113798301B

CN113798301B - Demetallization treatment method for FCC spent catalyst

Info

Publication number: CN113798301B
Application number: CN202010531401.5A
Authority: CN
Inventors: 任靖; 于金海; 吕岩; 祝平; 张南
Original assignee: China Petroleum and Chemical Corp; Sinopec Catalyst Co
Current assignee: China Petroleum and Chemical Corp; Sinopec Catalyst Co
Priority date: 2020-06-11
Filing date: 2020-06-11
Publication date: 2023-04-18
Anticipated expiration: 2040-06-11
Also published as: CN113798301A

Abstract

The invention relates to the field of catalyst recycling, and discloses a demetallization treatment method of FCC (fluid catalytic cracking) waste catalyst, which comprises the following steps of 1) crushing the FCC waste catalyst to obtain crushed FCC waste catalyst; 2) Mixing the crushed FCC dead catalyst with water to obtain a suspension; 3) Magnetically separating the suspension obtained in the step 2), wherein the crushing treatment enables the Dv (90) value of the crushed FCC waste catalyst to be below 25 mu m. The method can obtain low-magnetism materials with low pollution metal content, realizes the aim of demetallizing the FCC spent catalyst, and has the advantages of simple process, low production cost, strong geographical adaptability, safety and environmental protection.

Description

Demetallization treatment method for FCC spent catalyst

Technical Field

The invention relates to the field of catalyst recycling, in particular to a demetallization treatment method for FCC (fluid catalytic cracking) waste catalyst.

Background

The FCC catalyst is the catalyst with the largest use amount in the petroleum processing process, and metal elements in crude oil are continuously deposited on the surface of the catalyst along with the continuous recycling of the catalyst, so that the metal poisoning of the catalyst is caused, and the catalytic cracking activity and selectivity of the catalyst are greatly reduced. Therefore, such catalyst with high metal content and reduced activity and selectivity must be periodically discharged to form FCC spent catalyst. The pollution metals in the FCC spent catalyst are V, fe, ni, cu, etc., wherein V and Ni are elements with larger harm. The waste FCC catalyst is HW50 type hazardous waste specified in national hazardous waste records (2016 edition), and the waste FCC catalyst is produced in large quantity every year, and the harmless treatment of the waste FCC catalyst is important day by day.

Currently, the common treatment methods for the FCC spent catalyst are sorting and landfill treatment. After the FCC spent catalyst is discharged from the refinery unit, the part with lower metal content can be recovered for reuse by adopting a specific sorting mode. The separated residual waste FCC catalyst is subjected to landfill treatment by a professional hazardous waste treatment factory. The sorting and recycling mode does not reduce the waste FCC catalyst fundamentally, only prolongs the service life of the FCC catalyst properly, and finally forms the waste FCC catalyst to be treated. The landfill treatment mode not only occupies a large amount of land resources, but also can cause soil pollution and seriously harm the living environment of human beings. The pollution metal in the FCC waste catalyst is a main cause of causing the waste catalyst to become dangerous waste, and in order to reduce the harm of the FCC waste catalyst and perform resource utilization of the FCC waste catalyst, the content of the pollution metal in the FCC waste catalyst must be reduced. CN1078100C discloses a method for removing Ni from FCC waste catalyst by carbonylation, which uses carbon monoxide and Ni to generate gaseous nickel carbonyl material under specific reaction conditions to remove Ni from FCC waste catalyst. CN108190910A uses acid solution and alkali solution to leach FCC spent catalyst to remove the metal element contamination in the spent FCC catalyst, the acid solution is hydrochloric acid, sulfuric acid, nitric acid or oxalic acid solution, and the alkali solution is ammonia, sodium hydroxide or sodium carbonate solution. CN106480318A discloses a method for recovering Ni and V from FCC waste catalyst by using reduction smelting method, after FCC waste catalyst is uniformly mixed with reducing agent, trapping agent and fluxing agent, smelting is carried out for a certain time under high temperature condition, nickel-vanadium-iron melt and slag melt are obtained, and nickel-vanadium-iron ingot and slag can be finally obtained through further treatment. However, the above method has the following problems: (1) the process flow is complex and requires operating conditions such as high temperature and the like; (2) Partial methods have unsatisfactory demetallization effect, and the removal rate of the polluted metal is low; (3) Toxic and harmful substances or corrosive substances are used in the treatment process, and new three-waste pollution is easily generated to damage the environment and harm the human health; and (4) the economic cost is high, and the industrial application is difficult to put into practice.

Therefore, there is a need for a more feasible method for the demetallization of FCC spent catalyst.

Disclosure of Invention

The invention aims to solve the problems of complex demetallization treatment process, low metal removal rate, great environmental pollution and high economic cost of the waste FCC catalyst in the prior art, and provides a demetallization treatment method of the waste FCC catalyst.

The inventor of the present invention found through intensive research that heavy metals are mainly deposited on the surface of the FCC waste catalyst and have obvious magnetic difference with the internal framework structure in the use process of the FCC catalyst, and the surface layer of the FCC catalyst particle contaminated by more metal impurities is peeled from the silicon-aluminum framework contaminated by less metals by crushing the FCC waste catalyst particle to a specific particle size, and then the two are separated by a wet magnetic separation technology to form a low magnetic material with low heavy metal content and a high magnetic material enriched with heavy metals, thereby completing the present invention.

Accordingly, the present invention provides a method for demetallizing an FCC spent catalyst, comprising the steps of,

1) Crushing the FCC waste catalyst to obtain a crushed FCC waste catalyst;

2) Mixing the crushed FCC dead catalyst with water to obtain a suspension;

3) Magnetically separating the suspension obtained in the step 2),

wherein the pulverization treatment is performed so that the Dv (90) value of the pulverized spent FCC catalyst is 25 μm or less.

Preferably, in step 1), the pulverization treatment includes one or more of ball mill grinding, rod mill grinding, impact mill pulverization, and jet milling.

Preferably, the pulverization treatment is carried out such that the Dv (90) value of the pulverized FCC waste catalyst is 5 to 20 μm.

Preferably, in the step 2), the content of the crushed FCC waste catalyst in the suspension is 1 to 50 wt%; more preferably, in the step 2), the content of the crushed FCC waste catalyst in the suspension is 20 to 40 wt%.

Preferably, the suspension obtained in the step 2) is sent to a wet magnetic separator for magnetic separation.

Preferably, the wet magnetic separator is selected from a permanent magnet drum magnetic separator, a wet strong magnetic plate type magnetic separator or an electromagnetic vertical ring type magnetic separator.

Preferably, the magnetic field strength of the wet magnetic separator is 0.3-3T, and the magnetic field gradient has a magnitude greater than 1T/m.

Preferably, in the wet magnetic separator, the high magnetic material in the suspension is adsorbed on a moving member of the wet magnetic separator and moves along with the moving member, and the suspension is separated by a method of flushing the high pressure medium after the magnetic field is separated to obtain a high magnetic material suspension and obtain a low magnetic material suspension without the high magnetic material.

Preferably, the method further comprises the step of filtering and drying the high-magnetic material suspension and the low-magnetic material suspension respectively to obtain a high-magnetic material and a low-magnetic material.

Preferably, the filtration is one or more of vacuum filtration, centrifugal filtration and pressure filtration.

Preferably, the drying temperature is 80-500 ℃, and the drying time can be 1-30h.

According to the method, by crushing the FCC waste catalyst particles to a specific particle size, the surface layer of the FCC catalyst particles polluted by more metal impurities is peeled from the silicon-aluminum framework with less polluted metal, and then the FCC catalyst particles and the silicon-aluminum framework are separated by a wet magnetic separation technology to form a low-magnetic material with low heavy metal content and a high-magnetic material rich in heavy metal. After the low-magnetism material and the high-magnetism material are formed, the two materials can be respectively treated and applied according to the heavy metal content characteristics of the two materials, so that the treatment efficiency of the FCC spent catalyst is improved, and the method has important significance for environmental protection and economic sustainable development.

Detailed Description

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

The invention provides a demetallization treatment method of FCC dead catalyst, wherein the method comprises the following steps,

1) Crushing the FCC waste catalyst to obtain crushed FCC waste catalyst;

2) Mixing the crushed FCC dead catalyst with water to obtain a suspension;

3) Magnetically separating the suspension obtained in the step 2),

According to the present invention, in the step 1), the FCC waste catalyst is pulverized to have a Dv (90) value of 25 μm or less, and from the viewpoint of further separating the magnetic substance from the suspension, it is preferable that in the step 1), the pulverization treatment is performed so that the Dv (90) value of the pulverized FCC waste catalyst is 5 to 20 μm.

In addition, when the particle size of the crushed FCC spent catalyst is below 5 μm, on one hand, the crushing process is long in time and high in energy consumption, and is not suitable for the model selection of industrial equipment and the operation cost; on the other hand, the negative influence of the hydrodynamic resistance of the particles on the magnetic separation process is enhanced, and the magnetic separation effect is deteriorated. When the particle size of the pulverized FCC waste catalyst is more than 25 μm, the separation of high magnetic materials becomes significantly insufficient.

According to the present invention, preferably, in the step 2), the content of the crushed FCC waste catalyst in the suspension is 1 to 50 wt%; more preferably, in the step 2), the content of the crushed FCC waste catalyst in the suspension is 20 to 40 wt%. When the content of the FCC waste catalyst in the suspension is less than 1 wt%, there are problems of excessively low concentration, small treatment amount, and increased running cost. When the content of the FCC spent catalyst in the suspension is higher than 50 wt%, the problems of poor slurry fluidity, poor material dispersion effect and easy agglomeration exist.

According to the invention, the suspension obtained in step 2) is preferably fed to a wet magnetic separator for magnetic separation. The wet magnetic separator is selected from a permanent magnetic drum magnetic separator, a wet strong magnetic plate type magnetic separator or an electromagnetic vertical ring type magnetic separator. As the wet magnetic separator, for example, a magnetic separator of the SLon series type of Ganzhou golden ring magnetic separation, a magnetic separator of the CTB/N/S series type of Ganzhou golden ring magnetic separation, a magnetic separator of the LJDC series type of Shenyang Longji electromagnetic science, ltd, a magnetic separator of the CTN series type of Shenyang Longji electromagnetic science, ltd, or the like can be used.

Preferably, the magnetic field strength of the wet magnetic separator is 0.3-3T, the magnetic field gradient has a magnitude greater than 1T/m; more preferably, the magnetic field strength of the wet magnetic separator is 0.8-2.0T, the magnetic field gradient has a magnitude of 10-150000T/m, more preferably the magnetic field gradient has a magnitude of 100-100000T/m, even more preferably the magnetic field gradient has a magnitude of 1000-100000T/m.

According to the invention, in the wet magnetic separator, the high-magnetic material in the suspension is adsorbed on the moving member of the wet magnetic separator and moves along with the moving member, and the suspension is separated by a method of flushing the high-pressure medium after the magnetic field is separated to obtain the high-magnetic material suspension and obtain the low-magnetic material suspension without the high-magnetic material.

According to the invention, preferably, the method further comprises filtering and drying the high-magnetic material suspension and the low-magnetic material suspension respectively to obtain a high-magnetic material and a low-magnetic material.

According to the present invention, the filtration may be various methods generally used in the art for solid-liquid separation, and preferably, the filtration is one or more of vacuum filtration, centrifugal filtration and pressure filtration.

In addition, the drying may be performed by various methods generally used in the art, for example, the drying temperature may be 80 to 500 ℃, and the drying time may be 1 to 30 hours; preferably, the drying temperature can be 90-300 ℃, and the drying time can be 5-24h.

Examples

The present invention will be described in detail below by way of examples, but the present invention is not limited to the following examples.

In the following examples, the wet magnetic separator used was an SLon series magnetic separator of the Ganzhou golden ring magnetic separation facility, inc., which was an electromagnetic vertical ring magnetic separator. The magnetic separator of the type finishes the adsorption of magnetic particles by utilizing a high-gradient magnetic field generated by a magnetic medium under the condition of an electromagnetic field, and can adjust the magnetic field intensity and the magnetic field gradient by changing the current intensity and the radius of a filamentous medium in a magnetic medium box.

In the following examples, the V content was measured by inductively coupled plasma atomic emission spectrometry (ICP-AES), and the Ni content was measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). Dv (90) was measured using a laser diffraction particle size analyzer.

Example 1

1) 10kg of FCC spent catalyst was ground to a Dv (90) of 10 μm using a ball mill.

2) The ground material was added to 40kg of water to prepare a suspension having a concentration of 20% by weight.

3) The wet magnetic separation is carried out under the conditions that the magnetic field intensity is 2T and the magnetic field gradient of the surface of the magnetic medium is about 100000T/m. And (3) injecting the turbid liquid into a magnetic separator for magnetic separation, adsorbing high-magnetism particles in the slurry on the surface of a magnetic medium, bringing the particles to a top non-magnetic field area by a rotating ring, flushing the particles into a collecting tank for high-magnetism materials by flushing water, and allowing the low-magnetism particles and the non-magnetic particles to pass through the magnetic medium under the action of gravity and fluid force and enter the collecting tank for low-magnetism materials.

4) And respectively carrying out vacuum filtration (the pressure is-0.05 MPa) on the obtained high-magnetism slurry and low-magnetism slurry, and drying for 5 hours at the temperature of 300 ℃ to obtain high-magnetism materials and low-magnetism materials.

Wherein, the yield of the high magnetic material and the low magnetic material and the V, ni content in each material are shown in table 1.

TABLE 1

Name of material	Yield/%	V content/ppm	Ni content/ppm
				Raw materials	100	7200	7500
High magnetic material	17	32100	34500
				Low magnetic material	80	1500	1800

Example 2

1) 50kg of spent FCC catalyst was crushed by impact milling to a Dv (90) of 20 μm.

2) The ground material was added to 75kg of water to prepare a suspension having a concentration of 40% by weight.

3) The wet magnetic separation is carried out under the conditions that the magnetic field intensity is 0.8T and the magnetic field gradient of the surface of the magnetic medium is about 100T/m. Injecting the turbid liquid into a magnetic separator for magnetic separation, adsorbing high-magnetism particles in the slurry on the surface of a magnetic medium, bringing the particles to a top nonmagnetic field region by a rotating ring, flushing the particles into a collecting tank of the high-magnetism material by flushing water, and allowing low-magnetism particles and nonmagnetic particles to pass through the magnetic medium under the action of gravity and fluid force and enter the collecting tank of the low-magnetism material.

4) And respectively carrying out centrifugal sedimentation treatment on the obtained high-magnetism slurry and low-magnetism slurry, then removing clear liquid, and drying the settled layer material formed by centrifugal treatment at 90 ℃ for 24 hours to obtain a high-magnetism material and a low-magnetism material.

Wherein, the yield of the high magnetic material and the low magnetic material and the V, ni content in each material are shown in table 2.

TABLE 2

Name of material	Yield/%	V content/ppm	Ni content/ppm
				Raw materials	100	7200	7500
High magnetic material	33	15000	18000
				Low magnetic material	64	2700	2200

Example 3

The procedure is as in example 1, except that in step 1) the particles of spent catalyst are ball-milled to a Dv (90) of 5 μm; preparing suspension liquid with the concentration of 30 weight percent in the step 2), and obtaining high-magnetic materials and low-magnetic materials in the same way.

Wherein, the yield of the high magnetic material and the low magnetic material and the V, ni content in each material are shown in table 3.

TABLE 3

Name of material	Yield/%	V content/ppm	Ni content/ppm
				Raw materials	100	7200	7500
High magnetic material	14	41300	48500
				Low magnetic material	82	750	550

Example 4

The process is carried out as in example 1, except that in step 3), the wet magnetic separation is carried out under conditions of a magnetic field strength of 1.5T and a magnetic field gradient at the surface of the magnetic medium of 1000T/m. High magnetic material and low magnetic material are obtained identically.

Wherein, the yield of the high magnetic material and the low magnetic material and the V, ni content in each material are shown in table 4.

TABLE 4

Name of material	Yield/%	V content/ppm	Ni content/ppm
				Starting materials	100	7200	7500
High magnetic material	12	32400	35100
				Low magnetic material	84	3320	3410

Comparative example 1

The procedure of example 1 was followed except that 2kg of the FCC spent catalyst in step 1) was ground to a particle size of 30 μm using a ball mill to obtain high magnetic materials and low magnetic materials in the same manner.

Wherein, the yield of the high magnetic material and the low magnetic material and the V, ni content in each material are shown in table 5.

TABLE 5

Name of material	Yield/%	V content/ppm	Ni content/ppm
				Raw materials	100	7200	7500
High magnetic material	24	10500	14500
				Low magnetic material	70	5500	5300

Comparative example 2

The procedure of example 1 was followed except that the FCC waste catalyst in step 1) was ground to a Dv (90) of 40 μm using a ball mill, and high magnetic material and low magnetic material were obtained identically.

The yields of the high magnetic material and the low magnetic material and the V, ni contents in the respective materials are shown in table 6.

TABLE 6

Name of material	Yield/%	V content/ppm	Ni content/ppm
				Starting materials	100	7200	7500
High magnetic material	29	8500	8800
				Low magnetic material	67	6500	6800

Comparative example 3

The procedure of example 1 was followed except that the FCC spent catalyst in step 1) was ground to a Dv (90) of 2 μm using a ball mill, and high magnetic material and low magnetic material were obtained in the same manner.

Wherein, the yields of the high magnetic material and the low magnetic material and the V, ni content in each material are shown in table 7. In the group of experiments, as the particle size of the particles is too small, the hydrodynamic resistance of the particles in the slurry is obviously greater than the magnetic force of the particles, so that the particles with high heavy metal content cannot be effectively adsorbed by the magnetic medium, the yield of the high-magnetic material is obviously reduced, and part of the particles with high heavy metal content enter the low-magnetic material.

TABLE 7

Name of material	Yield/%	V content/ppm	Ni content/ppm
				Raw materials	100	7200	7500
High magnetic material	5	32500	35050
				Low magnetic material	90	5830	6050

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims

1. A demetallization treatment method of FCC dead catalyst is characterized in that the method comprises the following steps,

1) Crushing the FCC waste catalyst to obtain crushed FCC waste catalyst;

2) Mixing the crushed FCC dead catalyst with water to obtain a suspension;

3) Magnetically separating the suspension obtained in the step 2),

wherein the crushing treatment ensures that the Dv (90) value of the crushed waste FCC catalyst is 5-10 mu m, and the crushing treatment ensures that the surface layer of the waste FCC catalyst particles is peeled from a silicon-aluminum framework,

the content of the crushed FCC dead catalyst in the suspension is 1 to 50 weight percent,

sending the suspension obtained in the step 2) into a wet magnetic separator for magnetic separation.

2. The treatment method according to claim 1, wherein in step 1), the pulverization treatment comprises one or more of ball mill grinding, rod mill grinding, impact mill grinding, and jet milling.

3. The process of claim 1, wherein the suspension of the crushed FCC spent catalyst in step 2) has a content of 20 to 40 wt%.

4. The process of any one of claims 1 to 3 wherein the wet magnetic separator is selected from a permanent magnet drum separator, a wet strong magnetic plate separator or an electromagnetic vertical ring separator.

5. The process of any one of claims 1 to 3, wherein the magnetic field strength of the wet magnetic separator is between 0.3 and 3T and the magnetic field gradient has a magnitude greater than 1T/m.

6. The process of any one of claims 1 to 3, wherein in the wet magnetic separator, the high magnetic material in the suspension is adsorbed on a moving member of the wet magnetic separator and moves along with the moving member, and the high magnetic material suspension is separated by a method of high pressure medium showering after the magnetic field is separated, and the low magnetic material suspension with the high magnetic material removed is obtained.

7. The process of claim 6, further comprising filtering and drying the high magnetic material suspension and the low magnetic material suspension to obtain a high magnetic material and a low magnetic material.

8. The process of claim 7, wherein the filtration is one or more of vacuum filtration, centrifugal filtration and pressure filtration.

9. The process according to claim 7, wherein the drying temperature is 80-500 ℃ and the drying time is 1-30h.