CN109225353B

CN109225353B - Method for reactivating waste FCC catalyst by controlled leaching, metal passivation and effective component compensation

Info

Publication number: CN109225353B
Application number: CN201710572731.7A
Authority: CN
Inventors: 卢国俭; 朱英杰; 邹翔
Original assignee: Lianyungang Normal College
Current assignee: Lianyungang Normal College
Priority date: 2017-07-11
Filing date: 2017-07-11
Publication date: 2021-09-21
Anticipated expiration: 2037-07-11
Also published as: CN109225353A

Abstract

The invention discloses a method for reactivating a waste FCC catalyst by controlled leaching, metal nickel passivation and active ingredient compensation reaction, and relates to the technical field of solid waste recycling. The specific revival method comprises the following steps: the controlled leaching impurity removal and hole expansion are carried out by using the controlled impurity removal reactivator, so that the corrosion of aluminum oxide can be effectively prevented in the heavy metal removal process; boric acid is used as a passivator of nickel, so that the catalytic activity of the residual nickel is inerted, meanwhile, the passivator can further inertize the deposited new metal nickel in the petroleum cracking process, and the loss of rare earth lanthanum oxide in the impurity removal process is compensated, so that the high-efficiency reactivation of the waste FCC catalyst is realized, and the micro-repetitive activity of the reactivated catalyst is improved by 8.68 percent compared with that of a fresh catalyst. The light oil yield of the reactivated catalyst is close to that of a fresh catalyst. Therefore, the technology of the invention has obvious catalyst reactivation effect, does not generate secondary pollution to the environment, is cleaner and is easier to implement.

Description

Method for reactivating waste FCC catalyst by controlled leaching, metal passivation and effective component compensation

Technical Field

The invention relates to a method for reactivating waste FCC spent catalysts through boric acid controlled leaching, metal nickel passivation and active ingredient compensation reaction, belonging to the technical field of solid waste treatment and comprehensive utilization.

Background

The FCC catalyst is prepared by pulping aluminum sol, pseudo-boehmite, silica sol and adhesive acid to obtain slurry, spray drying, exchanging ions by jin, and loading rare earth RE₂O₃And (4) ionizing and roasting to prepare the petroleum cracking catalyst. The FCC catalyst has become one of the most used catalysts in the petroleum industry due to its good selectivity, high activity, good stability and heat resistance, and good effects of inhibiting, reducing dehydrogenation, desulfurizing and preventing carbon deposition. However, when the FCC catalyst is used for a period of time, the FCC catalyst is poisoned and inactivated and discarded due to the effects of pollution of heavy metals (nickel, vanadium and iron), carbon deposition, granularity refinement, sintering, non-crystallization in the regeneration process and the like.

At present, the quantity of FCC catalysts which are scrapped in China every year is more than 21 million tons, and although the research on the reactivation utilization of the waste catalysts and the recovery of valuable metals is carried out for many years, the key technologies of deactivation, reactivation mechanism and reactivation are not broken through. Leading to the ever greater storage of spent FCC catalyst, the co-collection of these spent FCC catalysts is one of the most serious problems currently facing petroleum refiners, and the disposal of spent catalyst has become an important environmental issue since landfill disposal is no longer considered the best choice. Spent FCC catalyst is considered a hazardous waste and subject to strict environmental regulations. The only option is the environmental friendly revival recycling and valuable metal recovery, which can avoid the increase of the toxic and harmful threats to the environment, and compared with the prior landfill treatment technology, the method has more operability and is feasible in both economy and environment. Therefore, researchers at home and abroad have conducted a great deal of research on the reactivation and reuse of the waste FCC catalyst. The chemical reactivation method is to react the waste FCC catalyst with various acids to make the heavy metal deposited on the catalyst and the acids react chemically, to clean the heavy metal or reduce the toxicity of the heavy metal, and to clean the blocked channel, so as to recover the specific surface area, pores and the like of the catalyst. However, the activation effect of acid to remove nickel is not ideal.

For example, the Demet technology adopted by ChemCat corporation in America abroad is an oxidation-vulcanization-chlorination-washing-activation process, the method has a good effect of removing heavy metal nickel, the activity of the reactivated catalyst is good, the oxidation-vulcanization requirement is met, when the temperature is increased from 538 ℃ to 760 ℃, the removal rate of alum is in positive correlation with the temperature, the removal rate of alum can reach 50%, and the removal rate of nickel in a vulcanizer can reach 90% at most. However, the technology has not been applied because the process is complex, the reaction conditions are harsh, the environment is polluted, and one-time operation is very large. The domestic Zhengjieyi and the like adopt FCC reactivated catalysts obtained by oxidation, acid leaching, water washing, drying and activation, micropores of the catalysts obtained by treatment are recovered, but the removal rate of heavy metals of nickel and alum is lower, and cut parts of aluminum are dissolved in strong acid solution, so that the acidity of the catalysts is reduced. The Lichunyi and the like adopt inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid, perchloric acid and the like to carry out demetallization reactivation research on the waste FCC catalyst, and the results show that the nickel removal effect of the inorganic acid is very poor, so that the activity of the reactivated catalyst is poor. The applicant adopts a method of controllably leaching out and removing nickel and iron by using mixed acid, reserving catalyst acid component aluminum oxide, and activating by loading rare earth metal again to carry out reactivation and regeneration research on the waste FCC catalyst, and the result shows that the removal rate of Ni reaches 45%, but alumina and rare earth lanthanum oxide are lost in the reaction process, and the removal of nickel is not thorough, so that the reactivation catalyst activity is increased, but the use time is short. The domestic patent 'a method for reactivating FCC spent catalyst' (patent number: 200810014209.8) discloses a method for reactivating spent FCC catalyst, which is characterized in that the blocked catalyst micropores are unblocked by the synergistic action of inorganic acid and organic acid, the catalyst skeleton is reconstructed, but the effect of leaching heavy metal nickel by hydrochloric acid is only about 30%, the activity of heavy metal nickel and nickel oxide deposited on the catalyst is higher, the dehydrogenation or coking effect is more obvious, and the catalyst is deactivated more quickly after activation. The domestic patent application number (201510178636. X) discloses a method for reactivating a waste catalyst by carrying out gas-solid phase reaction on gas-phase silicon tetrachloride and a waste FCC catalyst.

Most of the existing methods for reactivating the waste FCC catalyst adopt hydrochloric acid, sulfuric acid or sulfuration or chlorination to remove heavy metal nickel, not only has low removal efficiency and complex process, but also often removes most of effective components, thereby causing acidity reduction of the reactivated catalyst and catalyst framework collapse, and simultaneously generating a large amount of waste acid liquor to cause secondary pollution to the environment. Therefore, the invention is a new method with simple process, environmental protection and high activity of the reactivated FCC catalyst, and has important significance for improving the light oil rate and the environment in petroleum cracking.

Disclosure of Invention

The invention aims to overcome the defects of the prior art for reactivating the waste FCC catalyst and provides a method which has high activity of the reactivated catalyst, mild process conditions, environmental protection and capability of replacing a fresh catalyst with the reactivated product. The inventor of the patent carries out deep research on the technology for reactivating the waste FCC catalyst at home and abroad and aims to find a new method for solving the defects of the prior art. Compared with the prior art, research shows that the boric acid controlled leaching is adopted, so that heavy metals can be removed, metal nickel can be passivated, and effective components are adopted to compensate the reaction method, so that the reactivation of the waste FCC catalyst is realized, and the invention is completed.

The purpose of the invention is realized as follows: a method for reactivating a spent FCC catalyst for controlled leaching, metallic nickel passivation and active ingredient compensation reactions, which is mainly realized by the following steps:

(1) physically sieving and sorting the waste FCC catalyst to obtain the waste catalyst with the granularity of more than 30 mu m and light pollution degree, and reactivating by adopting boric acid controlled leaching, metal nickel passivation and effective component compensation technologies. The material granularity of the catalytic cracking waste catalyst is 30-120 mu m;

(2) preparing a controlled impurity removal reactivator, namely mixing and stirring boric acid, glycerol and hydrochloric acid with different mass fractions to prepare boric acid aqueous solutions with different mass fractions and strong acidity.

(3) Adding 500g of the catalyst (particles are larger than 30 mu m, the same below) obtained in the step (1) into a glass beaker, adding a controlled impurity removal reactivator aqueous solution for reaction, mechanically stirring and heating, controlling the pH value in the reaction process within the range of 1.0-3.0 and controlling the reaction time within 3-5 hours, wherein the liquid-solid ratio of the reaction system is 6: 1. Washing the reaction product with deionized water, leaching the catalyst filter cake, and removing toxic components such as nickel, alum, iron, sodium and the like.

(4) And (3) adding the product obtained in the step (3) into a three-mouth conical flask, respectively adding a lanthanum nitrate (1.2 times of the actual loss of the waste catalyst in the reaction process) solution and boric acid aqueous solutions with different concentrations, simultaneously carrying out impregnation loading, carrying out impregnation at the temperature of 45 ℃ for 6-8 hours, and carrying out vacuum filtration.

(5) Drying and dehydrating the product obtained in the step (4), wherein the treatment temperature is 120 ℃. And roasting the dehydrated catalyst in a muffle furnace for 3-4 hours to load cerium oxide and boron oxide, and removing carbon deposition and oil stain to obtain the reactivated catalyst.

Preferably, the mass percent concentration of the boric acid used as the impurity removal reactivation agent in the step (2) is set to be in the range of 1-6%, the addition amount of the glycerol is 0.02%, and the addition amount of the hydrochloric acid enables the pH value of the aqueous solution of the boric acid to be not less than 1, so that heavy metals deposited on the catalyst can be effectively removed, and the corrosion of the acidic alumina can be inhibited.

Preferably, the mass fraction of the passivating agent boric acid aqueous solution in the step (3) is 0.03-0.06%.

Preferably, the calcination temperature in the step (4) is 740-760 ℃.

The method of the invention has the following principle:

through research and comparison of reaction characteristics of aluminum oxide, silicon dioxide, rare earth oxide and heavy metals of nickel, vanadium, iron elements or compounds in the waste FCC catalyst and the fresh catalyst, the waste FCC catalyst is found to be ineffective mainly due to blockage of heavy metals and micropores deposited on the surface of the catalyst. Through the controlled leaching of boric acid, partial deposited heavy metal and sodium ions in catalyst micro cages and pore canals are removed by utilizing the weak acidity of boric acid, the specific surface area of the catalyst is increased, the poison of the heavy metal and the sodium ions to the catalyst is reduced, meanwhile, because the controlled leaching is adopted, the waste catalyst alumina is not lost, and the acidity of the catalyst is not weakened. The heavy metal nickel which is not removed and the lanthanum oxide which is lost by controlled leaching are passivated and compensated by adopting an impregnation method to increase the heavy metal resistance and the desulfurization capability of the catalyst.

Compared with the prior art, the invention has the advantages that:

it can overcome the loss of alumina in the course of reactivation in the existent technology, and can make the acidity of reactivation catalyst retain stable, and the stripping rate of heavy metal nickel can be up to above 35%. It can make the unremoved metal nickel be passivated mostly in the petroleum cracking process or the regeneration process, thereby improving the catalytic performance of the catalyst. Compared with the prior art, the reactivation method is simpler, has strong operability, and the reactivated catalyst has low metallic nickel content, high specific surface area, good activity and performance close to that of a fresh catalyst.

Drawings

For ease of illustration, the invention is described in detail by the following detailed description and the accompanying drawings.

FIG. 1 is a graph of analytical data for a sample of spent catalytic FCC catalyst used in various embodiments of the invention

FIG. 2 is a phase analysis diagram of a sample of spent catalytic FCC catalyst used in various embodiments of the invention

FIG. 3 is a flow diagram of a spent FCC catalyst rejuvenation process according to various embodiments of the invention

FIG. 4 chemical composition analysis data plot of reactivated catalyst

FIG. 5 quality index plot for rejuvenating FCC catalyst

FIG. 6 test chart for rejuvenating FCC catalyst performance

Evaluation of catalyst: evaluation of the catalyst was carried out on a fixed-bed FFB fluidized bed. Raw material oil of a Ruqing petrochemical compound is selected as raw material, the reaction temperature is 520 ℃, and the agent-oil ratio is 3.95.

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

Example 1: the waste catalyst with the particle size larger than 30 mu m is selected by screening (the same below), the waste FCC catalyst is reacted with an impurity removal reactivator, (the waste FCC catalyst in the embodiment is taken as an original agent, the analysis data of a test sample is shown in figure 1, the analysis data of the phase is shown in figure 2, the same examples are given below), 1% of the impurity removal reactivator and the waste catalyst are selected to carry out impurity removal reaction under the control that the liquid-solid ratio is 6: 1, the reaction time is 3 hours, the pH value in the process is controlled to be not less than 1, the filter residue is deionized and washed for 2 times, after 2 times of leaching, the filter residue is soaked in 0.03% of boric acid and lanthanum nitrate (the adding amount of the lanthanum nitrate is calculated according to the mass fraction of the lanthanum oxide lost by impurity removal under the control that the lanthanum nitrate is added under the conditions that the immersion temperature is 45 ℃, the immersion time is 6 hours, vacuum filtration is carried out, the drying and dehydration are carried out at 120 ℃, the roasting is carried out at the temperature of 740 ℃, and the roasting time is carried out for 3 hours, and the sample of the reactivated is taken as a sample 1. And (3) analyzing chemical elements of the obtained reactivated catalyst, and measuring the specific surface area and the pore volume. See fig. 4, 5. The chemical element analysis in fig. 1 and 4 was carried out by plasma spectrophotometry, and the specific surface area and pore volume were measured by BET method (the same in the following examples).

Example 2: selecting 2% of impurity-removing reactivator and waste catalyst to carry out impurity-removing reaction under control, wherein the liquid-solid ratio is 6: 1, the reaction time is 4 hours, the pH value in the process is controlled to be not less than 1, the filter residue is deionized and washed for 2 times, the filter residue is leached for 2 times, is soaked in 0.04% boric acid and lanthanum nitrate solution, the soaking temperature is 45 ℃, the soaking time is 7 hours, the filter residue is vacuumized and filtered, dried and dehydrated at 120 ℃, roasted at 750 ℃, and roasted for 3.5 hours, so that a reactivated catalyst sample is obtained, and the sample is recorded as a sample 2. And (3) analyzing chemical elements of the obtained reactivated catalyst, and measuring the specific surface area and the pore volume. See fig. 4, 5.

Example 3: selecting 3% of impurity-removing reactivator and waste catalyst to carry out impurity-removing reaction under control, wherein the liquid-solid ratio is 6: 1, the reaction time is 5 hours, the pH value in the process is controlled to be not less than 1, the filter residue is deionized and washed for 2 times, after the filter residue is washed for 2 times, the filter residue is soaked in 0.05% boric acid and lanthanum nitrate solution, the soaking temperature is 45 ℃, the soaking time is 8 hours, the filter residue is vacuumized and filtered, dried and dehydrated at 120 ℃, roasted at 760 ℃, and roasted for 4 hours, so that a reactivated catalyst sample is obtained, and the sample is marked as a sample 3. And (3) analyzing chemical elements of the obtained reactivated catalyst, and measuring the specific surface area and the pore volume. See fig. 4, 5.

Example 4: selecting 4% of impurity-removing reactivator and waste catalyst to carry out impurity-removing reaction under control, wherein the liquid-solid ratio is 6: 1, the reaction time is 5 hours, the pH value in the process is controlled to be not less than 1, the filter residue is deionized and washed for 3 times, after washing for 3 times, the filter residue is soaked in 0.03% boric acid and lanthanum nitrate solution, the soaking temperature is 45 ℃, the soaking time is 8 hours, vacuumizing and filtering are carried out, drying and dehydrating are carried out at 120 ℃, roasting is carried out at 760 ℃, and the roasting time is 3 hours, so that a reactivated catalyst sample is obtained and is marked as sample 4. And (3) analyzing chemical elements of the obtained reactivated catalyst, and measuring the specific surface area and the pore volume. See fig. 4, 5.

Example 5: selecting 5% of impurity-removing reactivator and waste catalyst to carry out impurity-removing reaction under control, wherein the liquid-solid ratio is 6: 1, the reaction time is 4 hours, the pH value in the process is controlled to be not less than 1, the filter residue is deionized and washed for 3 times, the filter residue is leached for 3 times, is soaked in 0.04% boric acid and lanthanum nitrate solution, the soaking temperature is 45 ℃, the soaking time is 7 hours, the filter residue is vacuumized and filtered, dried and dehydrated at 120 ℃, roasted at 750 ℃ and roasted for 3 hours, and a reactivated catalyst sample is obtained and is marked as sample 5. And (3) analyzing chemical elements of the obtained reactivated catalyst, and measuring the specific surface area and the pore volume. See fig. 4, 5.

Example 6: selecting 6% of impurity-removing reactivator and waste catalyst to carry out impurity-removing reaction under control, wherein the liquid-solid ratio is 6: 1, the reaction time is 3 hours, the pH value in the process is controlled to be not less than 1, the filter residue is deionized and washed for 3 times, after washing for 3 times, the filter residue is soaked in 0.05% boric acid and lanthanum nitrate solution, the soaking temperature is 45 ℃, the soaking time is 6 hours, vacuumizing and filtering are carried out, drying and dehydrating are carried out at 120 ℃, roasting is carried out at 740 ℃, and the roasting time is 3 hours, so that a reactivated catalyst sample is obtained and is marked as a sample 6. And (3) analyzing chemical elements of the obtained reactivated catalyst, and measuring the specific surface area and the pore volume. See fig. 4, 5.

As can be seen from fig. 4 and 5, the contents of heavy metals such as Ni, V, Ca Fe, and Na in the reactivated catalyst are low, and the specific surface area and the microreflective activity index are significantly improved.

The reactivated catalysts obtained in the above examples were evaluated for catalytic cracking performance on a small fixed fluidized bed reactor. The catalytic performance of the spent FCC catalyst and the rejuvenated catalyst were evaluated. The reaction conditions were as follows: the reaction temperature is 500 ℃, the catalyst-oil ratio is 4.0, and the mass space velocity is 20h^-1(ii) a The raw oil used was heavy oil from Jiangsu New sea fossil Co., Ltd, and the evaluation result of cracking reaction performance is shown in FIG. 6. From the experimental results of fig. 6, it can be concluded that: the application of the reactivated catalyst to a catalytic cracking device can reduce the coke yield of the device and simultaneously improve the yield of gasoline and liquefied gas.

Claims

1. A method for rejuvenating a spent FCC catalyst with controlled leaching, metallic nickel passivation and active ingredient compensation, said rejuvenation method comprising the steps of:

(1) mixing and stirring boric acid, glycerol and hydrochloric acid with different mass fractions to prepare boric acid aqueous solutions with different mass fractions and strong acidity, wherein the mass fraction of the boric acid in the controlled impurity removal reactivator is 1-6%, the addition of the glycerol is 0.02%, the addition of the hydrochloric acid enables the pH of the controlled impurity removal reactivator solution to be not less than 1, and the characteristics of the controlled impurity removal reactivator can effectively leach heavy metals and sodium ions in the waste catalyst and protect aluminum oxide in the catalyst; (2) reacting the waste catalyst with the sieving granularity of more than 30 mu m with a controlled impurity removal reactivator, and washing and leaching the reaction product with deionized water to obtain a catalyst filter cake; (3) and (3) simultaneously soaking the loaded lanthanum oxide and the boron oxide in boric acid aqueous solution and lanthanum nitrate solution with different concentrations, roasting for 3-4 hours, and simultaneously removing carbon deposit and oil stain to obtain the reactivated catalyst.

2. The process of claim 1, wherein the spent FCC catalyst is subjected to controlled leaching, passivation by metallic nickel and active ingredient compensation, and the spent FCC catalyst is rejuvenated by the steps of: the liquid-solid ratio of the controlled leaching reaction system in the step (2) is 6: 1, the pH value in the reaction process is controlled within the range of 1.0-3.0, and the reaction time is 3-6 hours.

3. The process of claim 1, wherein the spent FCC catalyst is subjected to controlled leaching, passivation by metallic nickel and active ingredient compensation, and the spent FCC catalyst is rejuvenated by the steps of: the mass fraction of the passivating agent boric acid aqueous solution for the impregnation reaction in the step (3) is 0.03-0.06%, the temperature is 45-50 ℃, the impregnation time is 6-10 hours, the roasting time is 3-4 hours, and the roasting temperature is 740-760 ℃.