CN112675907A - In-situ combined regeneration method of deactivated titanium-silicon molecular sieve catalyst - Google Patents
In-situ combined regeneration method of deactivated titanium-silicon molecular sieve catalyst Download PDFInfo
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Abstract
The invention discloses an in-situ combination regeneration method of a deactivated titanium silicalite molecular sieve catalyst, which comprises the steps of sequentially treating the deactivated titanium silicalite molecular sieve catalyst with a solvent, a carbamide peroxide solution and an ionic liquid aqueous solution, and then treating the deactivated titanium silicalite molecular sieve catalyst with the solvent again to realize in-situ regeneration of the deactivated catalyst. The titanium-silicon molecular sieve obtained by the combined regeneration method of the invention basically recovers to the level of a fresh catalyst in the aspects of hydrogen peroxide conversion rate, propylene oxide selectivity and hydrogen peroxide effective utilization rate.
Description
Technical Field
The invention belongs to the field of petrochemical catalyst regeneration methods, and particularly relates to an in-situ combination regeneration method of a titanium silicalite molecular sieve catalyst.
Background
In 1983, Taramasso et al first published a report (US4410501) on the synthesis of a titanium silicalite molecular sieve (TS-1) with MFI structure. TS-1Has excellent selective catalytic oxidation performance, and uses H2O2The catalyst is an oxidant, shows high activity and selectivity in olefin epoxidation, aromatic hydrocarbon hydroxylation, ketone ammoximation, alcohol oxidation, alkane oxidation and other reactions, and a byproduct is only water, belongs to an environment-friendly process, so the catalyst is widely concerned by people. However, due to the limitation of the TS-1 pore channel size (0.56nm multiplied by 0.53nm) on the diffusion of reactants and products, the contact of the reactants and active centers is limited, meanwhile, the products cannot diffuse out of the molecular sieve pore channels in time, byproducts are easy to generate, and macromolecular byproducts are generated, so that the catalyst is inactivated.
CN105413745A discloses a method for removing carbon deposition from a deactivated titanium silicalite molecular sieve catalyst, which comprises soaking a deactivated titanium silicalite molecular sieve catalyst raw powder containing carbon deposition into a hydrogen peroxide solution, and then irradiating with ultraviolet light, and removing the carbon deposition by oxidative degradation under the combined action of ultraviolet light and hydrogen peroxide.
CN109126864A mixes the deactivated titanium-silicon molecular sieve catalyst with the alkaline compound solution, carries out hydrothermal treatment at 110 ℃ and 210 ℃ for 5-48 hours, mixes the titanium-silicon molecular sieve after the hydrothermal treatment of the alkaline solution with the acidic compound solution, then reacts for 0.5-24 hours at room temperature and 100 ℃, and finally carries out post-treatment to obtain the regenerated titanium-silicon molecular sieve.
CN110075914A provides a method for regenerating a deactivated titanium-silicon molecular sieve catalyst in an HPPO process. Through acid treatment, cyclic impregnation of a regeneration liquid and organic solvent treatment, metal impurities and reaction byproducts blocked in a molecular sieve pore channel are removed, lost framework titanium is supplemented, and the deactivated catalyst is regenerated.
CN105665002A mixes the deactivated titanium-silicon molecular sieve catalyst with an acid solution containing a cation trapping agent, stirs the mixture for 1 to 10 hours at the temperature of 20 to 120 ℃, washes the mixture to be neutral, and dries the mixture to obtain the titanium-silicon molecular sieve catalyst after acid treatment. Mixing the titanium silicalite molecular sieve catalyst after acid treatment with an alkaline solution, and reacting for 0.5-5 days at the temperature of 150 ℃ and 190 ℃ under autogenous pressure to obtain the titanium silicalite molecular sieve catalyst after base catalysis. And filtering the titanium silicalite molecular sieve catalyst after alkali treatment, washing until the pH value is 7-10, and drying and roasting to obtain the regenerated titanium silicalite molecular sieve catalyst.
However, the above treatment method has the technical problems of complicated operation, incomplete regeneration of the titanium silicalite molecular sieve, short service life of the catalyst and the like.
The invention provides an in-situ combination regeneration method of a titanium-silicon molecular sieve catalyst, which is characterized in that a deactivated catalyst is sequentially treated by a solvent, a carbamide peroxide solution, an ionic liquid and the solvent to realize in-situ regeneration of the deactivated catalyst. The method can be used without discharging the deactivated titanium silicalite molecular sieve catalyst from the reactor, and has simple and convenient operation. And the complete regeneration of the deactivated catalyst can be realized by adopting a combined regeneration mode.
Disclosure of Invention
The invention provides an in-situ combination regeneration method of a titanium-silicon molecular sieve catalyst, which is characterized in that a deactivated catalyst is sequentially treated by a solvent, a carbamide peroxide solution, an ionic liquid and the solvent to realize in-situ regeneration of the deactivated catalyst. The method can be used without discharging the deactivated titanium silicalite molecular sieve catalyst from the reactor, and has simple and convenient operation. And the complete regeneration of the deactivated catalyst can be realized by adopting a combined regeneration mode.
The invention provides an in-situ combination regeneration method of an inactivated titanium silicalite molecular sieve catalyst, which comprises the following steps:
(1) solvent washing: introducing the solvent into a reactor filled with deactivated titanium-silicon molecular sieve catalyst under the conditions of pressure of 0.5-2.0MPa, temperature of 30-100 ℃ and mass space velocity of 0.5-2h-1Treating for 0.5-12h under the condition of (1), and cleaning residual reactants and products on the catalyst;
(2) washing with a urea peroxide solution: after the step (1) is finished, introducing the carbamide peroxide solution into the reactor, wherein the pressure is 0.5-2.0MPa, the temperature is 60-100 ℃, and the mass space velocity is 0.2-2h-1Treating for 0.5-24h under the condition of (1);
(3) washing with an ionic liquid aqueous solution: after the step (2) is finished, introducing the ionic liquid aqueous solution into the reactor, wherein the pressure is 0.5-2.0MPa, the temperature is 60-100 ℃, and the mass space velocity is 0.5-2h-1Treating for 0.5-12h under the condition of (1);
(4) solvent washing: after the step (3) is finishedIntroducing the solvent into the reactor again under the conditions of pressure of 0.5-2.0MPa, temperature of 30-100 ℃ and mass space velocity of 0.5-2h-1Treating for 0.5-12h under the condition of (1), and cleaning the residual ionic liquid on the catalyst to obtain the regenerated titanium-silicon molecular sieve catalyst.
Preferably, the solvent is one or more of methanol, acetonitrile, and acetone.
Preferably, the mass fraction of the carbamide peroxide solution is 0.01-30%, and the solvent of the carbamide peroxide solution is one or more of water, methanol, acetonitrile and acetone.
Preferably, the ionic liquid is one or more of tetramethylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride and tetrabutylammonium bromide; the mass fraction of the ionic liquid aqueous solution is 0.5-10%.
The deactivated titanium-silicon molecular sieve catalyst is from olefin epoxidation, phenol hydroxylation or ketone ammoxidation.
Advantageous effects
The invention provides an in-situ combination regeneration method of a titanium-silicon molecular sieve catalyst, wherein a carbamide peroxide solution can decompose macromolecular deactivated species covering active sites, an ionic liquid aqueous solution can desorb partial deactivated species, and the combination of the two treatment modes has a synergistic effect, so that the activity of the regenerated catalyst can be completely recovered.
Detailed Description
The regeneration process of the present invention is further illustrated in detail by comparative examples and examples below. And (3) performing liquid phase epoxidation reaction on the inactivated titanium silicalite molecular sieve catalyst.
Comparative example 1:
5g of deactivated catalyst is filled in a constant temperature section of a fixed bed reaction tube, and a methanol solvent is introduced at the temperature of 120 ℃ under the pressure of 0.5MPa for treatment for 24 hours, wherein the feeding amount is 10 g/h. The comparative example A of the regenerated titanium silicalite molecular sieve catalyst is obtained.
Comparative example 2:
5g of deactivated catalyst is filled in a constant temperature section of a fixed bed reaction tube, urea peroxide aqueous solution is introduced at 1.0MPa and 80 ℃ for treatment for 12 hours, the feeding amount is 5g/h, and the mass fraction of the urea peroxide is 5%. The comparative example B of the regenerated titanium silicalite molecular sieve catalyst is obtained.
Comparative example 3:
5g of deactivated catalyst is filled in a constant temperature section of a fixed bed reaction tube, an ionic liquid aqueous solution is introduced at 1.5MPa and 60 ℃ for treatment for 6 hours, the feeding amount is 8g/h, and the used ionic liquid aqueous solution is a tetrapropylammonium chloride aqueous solution with the mass fraction of 5%. The comparative example C of the regenerated titanium silicalite molecular sieve catalyst is obtained.
Comparative example 4:
5g of deactivated catalyst is filled in a constant temperature section of a fixed bed reaction tube, and acetone solvent is introduced at the temperature of 120 ℃ under the pressure of 0.5MPa for treatment for 4 hours, wherein the feeding amount is 10 g/h. Then the urea peroxide aqueous solution is introduced for treatment for 4 hours, and the feeding amount is 5 g/h. The comparative example D of the regenerated titanium silicalite molecular sieve catalyst is obtained.
Example 1:
5g of deactivated catalyst is filled in a constant temperature section of a fixed bed reaction tube, and a methanol solvent is introduced at 0.5MPa and 60 ℃ for treatment for 6 hours, wherein the feeding amount is 10 g/h. Then, the urea peroxide aqueous solution is introduced, the feeding amount is 5g/h, the mass fraction of the urea peroxide is 5 percent, and the treatment time is 12 hours. Then introducing a tetramethylammonium chloride aqueous solution, wherein the feeding amount is 10g/h, and the mass fraction of tetramethylammonium chloride is 2%. The treatment time is 2 h. The methanol solvent was again introduced for 3 hours at a feed rate of 10 g/h. Example a regenerated titanium silicalite catalyst was obtained.
Example 2:
5g of deactivated catalyst is filled in a constant temperature section of a fixed bed reaction tube, and acetone solvent is introduced at 1.0MPa and 80 ℃ for treatment for 12 hours, wherein the feeding amount is 5 g/h. Then the carbamide peroxide methanol solution is introduced, the feeding amount is 5g/h, the carbamide peroxide mass fraction is 10 percent, and the processing time is 6 hours. Then introducing tetraethylammonium chloride aqueous solution, wherein the feeding amount is 5g/h, and the mass fraction of the tetraethylammonium chloride is 5%. The treatment time was 8 h. The acetone solvent was again introduced for 2 hours at a feed rate of 10 g/h. Example B of a regenerated titanium silicalite catalyst was obtained.
Example 3:
5g of deactivated catalyst is filled in a constant temperature section of a fixed bed reaction tube, acetonitrile solvent is introduced at 1.0MPa and 100 ℃ for treatment for 2 hours, and the feeding amount is 8 g/h. Then, the carbamide peroxide acetone solution is introduced, the feeding amount is 10g/h, the carbamide peroxide mass fraction is 12 percent, and the processing time is 2 hours. Then introducing tetrabutylammonium chloride aqueous solution, wherein the feeding amount is 6g/h, and the mass fraction of tetrabutylammonium chloride is 5%. The treatment time is 3 h. The acetonitrile solvent was again introduced for 6 hours at a feed rate of 10 g/h. Example C was obtained as regenerated titanium silicalite catalyst.
Example 4:
5g of deactivated catalyst is filled in a constant temperature section of a fixed bed reaction tube, and a methanol solvent is introduced at 1.0MPa and 80 ℃ for treatment for 2 hours, wherein the feeding amount is 8 g/h. Then, the urea peroxide aqueous solution is introduced, the feeding amount is 5g/h, the mass fraction of the urea peroxide is 15 percent, and the treatment time is 2 hours. Then introducing tetrabutylammonium bromide aqueous solution, wherein the feeding amount is 8g/h, and the mass fraction of tetrabutylammonium bromide is 8%. The treatment time was 6 h. The methanol solvent was again introduced for 12 hours at a feed rate of 5 g/h. Example D of a regenerated titanium silicalite catalyst was obtained.
Example 5:
the propylene epoxidation reaction is adopted as a probe reaction, and the regeneration effect of the deactivated titanium silicalite molecular sieve catalyst provided by the invention is inspected. The catalyst was dried at 80 ℃ before the reaction. 68.8g of hydrogen peroxide methanol solution is added into a stainless steel batch reactor, and the molar concentration of the hydrogen peroxide is 3 mol/L. Adding 0.33g of the regenerated catalyst with the granularity of 100-120 meshes, sealing the kettle, introducing propylene, maintaining the propylene pressure at 0.4MPa, and stirring at 40 ℃ for reaction for 1 h. The conversion rate of hydrogen peroxide is determined by adopting a potentiometric titration method, and the selectivity of the propylene oxide is analyzed by adopting gas chromatography. The reaction results are shown in the following table.
The main index for evaluating the performance of the liquid phase epoxidation reaction of propylene is H2O2Conversion rate of (X (H)2O2) Selectivity of PO (S), (PO)) and H2O2Effective utilization ratio (U (H)2O2) Calculated using the following formulas, respectively:
X(H2O2)＝n0(H2O2)-n(H2O2)/n0(H2O2)×100％
S(PO)＝n(P0)/[n(PO)+n(MME)+n(PG)]×100％
U(H2O2)＝[n(PO)+n(MME)+n(PG)]/[n0(H2O2)×X(H2O2)]×100％
in the formula, n0(H2O2) And n (H)2O2) Represents the initial reaction and the end of the reaction H2O2N (PO), n (MME) and n (PG) represent the quantitative concentrations of the substances PO, MME and PG in the reaction liquid product, respectively.
TABLE 1 Performance of molecular sieve samples for catalyzing epoxidation of propylene
Compared with the comparative example, the titanium silicalite molecular sieve obtained by the combined regeneration method of the invention basically recovers to the level of a fresh catalyst in the aspects of hydrogen peroxide conversion rate, propylene oxide selectivity and hydrogen peroxide effective utilization rate.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be able to cover the technical solutions and the inventive concepts of the present invention within the technical scope of the present invention.
Claims (6)
1. An in-situ combined regeneration method of a deactivated titanium silicalite molecular sieve catalyst is characterized by comprising the following steps: and (3) sequentially treating the deactivated titanium-silicon molecular sieve catalyst with a solvent, a carbamide peroxide solution and an ionic liquid aqueous solution, and then treating with the solvent again to realize in-situ regeneration of the deactivated catalyst.
2. The combined regeneration method according to claim 1, characterized in that it comprises the steps of:
(1) solvent washing: introducing the solvent into a reactor filled with deactivated titanium-silicon molecular sieve catalyst under the conditions of pressure of 0.5-2.0MPa, temperature of 30-100 ℃ and mass space velocity of 0.5-2h-1Treating for 0.5-12h under the condition of (1), and cleaning residual reactants and products on the catalyst;
(2) washing with a urea peroxide solution: after the step (1) is finished, introducing the carbamide peroxide solution into the reactor, wherein the pressure is 0.5-2.0MPa, the temperature is 60-100 ℃, and the mass space velocity is 0.2-2h-1Treating for 0.5-24h under the condition of (1);
(3) washing with an ionic liquid aqueous solution: after the step (2) is finished, introducing the ionic liquid aqueous solution into the reactor, wherein the pressure is 0.5-2.0MPa, the temperature is 60-100 ℃, and the mass space velocity is 0.5-2h-1Treating for 0.5-12h under the condition of (1);
(4) solvent washing: after the step (3) is finished, the solvent is introduced into the reactor again, the pressure is 0.5-2.0MPa, the temperature is 30-100 ℃, and the mass space velocity is 0.5-2h-1Treating for 0.5-12h under the condition of (1), and cleaning the residual ionic liquid on the catalyst to obtain the regenerated titanium-silicon molecular sieve catalyst.
3. The combined regeneration method according to claim 1, wherein the solvent is a combination of one or more of methanol, acetonitrile, and acetone.
4. The combined regeneration method according to claim 1, wherein the mass fraction of the carbamide peroxide solution is 0.01-30%, and the solvent of the carbamide peroxide solution is one or more of water, methanol, acetonitrile and acetone.
5. The combined regeneration method of claim 1, wherein the ionic liquid is one or more of tetramethylammonium chloride, tetraethylammonium chloride, tetrabutylammonium bromide; the mass fraction of the ionic liquid aqueous solution is 0.5-10%.
6. The combined regeneration method of claim 1, wherein the deactivated titanium silicalite catalyst is a catalyst after olefin epoxidation, phenol hydroxylation or ketone ammoxidation.
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| CN113769792A (en) * | 2021-08-25 | 2021-12-10 | 浙江工业大学 | Regeneration method of supported platinum group metal catalyst |
| CN114308118A (en) * | 2022-01-05 | 2022-04-12 | 江苏扬农化工集团有限公司 | In-situ regeneration method of titanium-silicon molecular sieve |
| CN114700108A (en) * | 2022-04-07 | 2022-07-05 | 中建安装集团有限公司 | Method for removing carbon deposition in inactivated propylene epoxy titanium silicalite molecular sieve catalyst |
| CN115805103A (en) * | 2021-09-14 | 2023-03-17 | 万华化学集团股份有限公司 | Regeneration method of deactivated titanium-silicon molecular sieve |
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