Anthraquinone process hydrogen peroxide palladium catalyst regeneration method

Abstract

The invention discloses an anthraquinone process hydrogen peroxide palladium catalyst regeneration method, and belongs to the field of catalyst regeneration. The regeneration method comprises the following steps: arranging a purging pipeline on a catalyst bed layer for feeding bubbling gas; the method comprises the following steps: soaking a catalyst bed layer in hot ionized water, dilute acetic acid, an ethanol solution and soft water in sequence, vacuumizing in the soaking process, and continuously bubbling by taking superheated saturated steam or N2 as bubbling gas; the method comprises the following steps: washing a catalyst bed layer with soft water, then purging the catalyst bed layer with purging gas, and gradually reducing the proportion of N2 in the purging gas and increasing the proportion of H2 in the purging process. Compared with the prior art, the regeneration method can thoroughly remove all inorganic and organic impurities on the palladium catalyst, is high in regeneration efficiency and low in cost, and has very good popularization and application values.

Description

Technical Field

[0001] The present invention relates to the field of catalyst regeneration, and particularly provides a method for regenerating a palladium catalyst for hydrogen peroxide by the anthraquinone method. Background Art

[0002] The mainstream process for domestic production of H 2 O 2 is the technology for producing hydrogen peroxide by the anthraquinone method using a fixed bed of palladium catalyst. This catalyst has the advantages of high hydrogenation activity, low dosage, easy regeneration, long service life, etc. In industrial production, the primary hydrogenation activity release period of the palladium catalyst is 6 - 12 months. As time goes by, the hydrogenation activity of the palladium catalyst will gradually decrease. When the hydrogenation activity of the palladium catalyst cannot meet the production requirements, it is called that the palladium catalyst "becomes deactivated".

[0003] Currently, for the "deactivated" palladium catalyst, methods such as steam purge regeneration method, solvent washing regeneration method, high - temperature regeneration method, oxidation liquid regeneration method, etc. are mainly used. These methods cannot effectively and thoroughly remove the harmful substances adhering to the active pores of the catalyst in actual application. After regeneration, the service cycle is generally 3 - 6 months, and moreover, the regeneration time is relatively long, greatly reducing the production efficiency. Summary of the Invention

[0004] The present invention aims at the above - mentioned deficiencies of the prior art and provides a green, environmentally friendly and efficient method for regenerating a palladium catalyst for hydrogen peroxide by the anthraquinone method.

[0005] The technical solution adopted by the present invention to solve its technical problems is: A method for regenerating a palladium catalyst for hydrogen peroxide by the anthraquinone method, which is characterized by including:

[0006] A purge pipeline is arranged in the catalyst bed layer for feeding bubbling gas.

[0007] The catalyst bed layer is soaked successively with hot deionized water, dilute acetic acid, ethanol solution and soft water. During the soaking process, vacuum is pumped, and superheated saturated steam or N 2 is used as the bubbling gas for continuous bubbling.

[0008] The catalyst bed layer is rinsed with soft water, and then the catalyst bed layer is purged with purge gas. During the purging process, the proportion of N 2 in the purge gas is gradually reduced and the proportion of H 2 is increased.

[0009] The catalyst bed layer refers to the palladium catalyst bed layer in the hydrogen peroxide reactor prepared by the anthraquinone method.

[0010] Preferably, 4 - 20 purge pipelines can be arranged in the catalyst bed layer. The purge height of the purge pipelines is the same as the height of the catalyst bed layer, and the pipe diameter The pipe wall is processed with a number of diameters The small holes have a spacing of 1.5 - 3 cm (along the axial direction of the purge pipeline) between adjacent small holes.

[0011] The diameter of the pipe is particularly preferably The diameter of the small holes is particularly preferably The spacing between adjacent small holes is particularly preferably 1.8 - 2.5 cm (along the axial direction of the purge pipeline).

[0012] Preferably, the purge pipeline is composed of a central pipe and a peripheral pipe, and the aperture of the small holes on the central pipe is larger than the aperture of the small holes on the peripheral pipe.

[0013] Preferably, each purge pipeline vertically or horizontally penetrates the catalyst bed, and the purging height can be the same as the height of the catalyst bed.

[0014] Preferably, a stainless steel wire mesh is wrapped outside the purge pipeline, and the aperture of the stainless steel wire mesh is 80 - 150 μm.

[0015] Preferably, the catalyst bed is soaked with hot ionic water 1 - 3 times, 30 - 60 minutes each time, the vacuum degree is -100 - -50 KPa (particularly preferably -80 - -50 KPa), the pressure of the superheated saturated steam is 0.3 - 0.6 MPa (particularly preferably 0.4 - 0.5 MPa), and the flow rate is 10 - 50 m 3 / h (particularly preferably 20 - 40 m 3 / h).

[0016] Preferably, the catalyst bed is soaked with dilute acetic acid 1 - 2 times, 45 - 90 minutes each time, the concentration of the dilute acetic acid is 30% - 60% (particularly preferably 30 - 50%), the vacuum degree is -70 - -30 KPa (particularly preferably -60 - -30 KPa), N 2 The flow rate of is 10 - 30 m 3 / h (particularly preferably 15 - 30 m 3 / h).

[0017] Preferably, the catalyst bed is soaked with an ethanol solution 1 - 2 times, 30 - 70 minutes each time, the concentration of the ethanol solution is 70% - 90% (particularly preferably 75% - 88%), the vacuum degree is 30 - 80 KPa (particularly preferably 30 - 60 KPa), N 2 The flow rate of is 10 - 40 m 3 / h (particularly preferably 20 - 30 m 3 / h).

[0018] Preferably, the catalyst bed is soaked with soft water 1 - 2 times, 10 - 50 minutes each time (particularly preferably 20 - 45 minutes), the vacuum degree is -100 - -50 KPa (particularly preferably -80 - -50 KPa), N2 The flow rate is 10 - 50 m 3 / h (particularly preferably 10 - 30 m 3 / h).

[0019] Preferably, the catalyst bed is rinsed with soft water until there are no impurities in the soft water, and the rinsing time is usually 30 - 90 min (particularly preferably 30 - 60 min).

[0020] Preferably, during the process of rinsing the catalyst bed with soft water, N is bubbled at a flow rate of 10 - 50 m 3 / h (particularly preferably 30 - 50 m 3 / h). 2 Bubble.

[0021] Preferably, the flow rate of the purge gas is 40 - 60 m 3 / h.

[0022] Preferably, first purge with pure N 2 for 0.5 - 1.5 h, then gradually increase the proportion of H in the purge gas. After the proportion of N 2 and H 2 reaches 1:1, purge for 0.5 - 1.5 h. Then gradually reduce the proportion of N in the purge gas 2 , and finally purge with pure H 2 for 0.5 - 1.5 h. 2 Bubble.

[0023] Preferably, before the proportion of N 2 and H 2 reaches 1:1, the proportion of H can be increased by reducing the flow rate of N in the purge gas and increasing the flow rate of H 2 , or by keeping the flow rate of N 2 different and only increasing the flow rate of H 2 . 2 2 2 2 2 2

[0024] Preferably, after the proportion of N 2 and H 2 reaches 1:1, the proportion of H can be increased by gradually reducing the flow rate of N in the purge gas 2 . 2 Bubble.

[0025] Preferably, the process of the method for regenerating the palladium catalyst for hydrogen peroxide by the anthraquinone method of the present invention is as follows:

[0026] 1) Fill the entire catalyst bed with thermionic water, soak it 1 - 3 times, 30 - 60 minutes each time. During the soaking process, evacuate the air and continuously bubble with superheated saturated steam. The vacuum degree is -100 to -50 KPa, the pressure of the superheated saturated steam is 0.3 - 0.6 MPa, and the flow rate is 10 - 50 m 3 / h;

[0027] 2) Soak the catalyst bed with dilute acetic acid 1 - 2 times, and continuously bubble with N 2 as the bubbling gas, 45 - 90 minutes each time. The concentration of the dilute acetic acid is 30% - 60%, the vacuum degree is -70 to -30 KPa, and the flow rate of N 2 is 10 - 30 m 3 / h;

[0028] 3) Soak the catalyst bed with ethanol solution 1 - 2 times, and continuously bubble with N 2 as the bubbling gas, 30 - 70 minutes each time. The concentration of the ethanol solution is 70% - 90%, the vacuum degree is 30 - 80 KPa, and the flow rate of N 2 is 10 - 40 m 3 / h;

[0029] 4) Soak the catalyst bed with soft water 1 - 2 times, and continuously bubble with N 2 as the bubbling gas, 10 - 50 minutes each time. The vacuum degree is -100 to -50 KPa, and the flow rate of N 2 is 10 - 50 m 3 / h;

[0030] After draining the soft water, rinse the bed with flowing soft water until there is no impurity in the soft water. The rinsing time is usually 30 - 90 minutes;

[0031] 5) Purge the catalyst bed with a purge gas at a flow rate of 40 - 60 m 3 / h. During the purging process, gradually reduce the proportion of N 2 in the purge gas and increase the proportion of H 2 until the proportion of N 2 is zero, and purge with pure H 2 to create a dry reduction atmosphere and complete the regeneration of the catalyst.

[0032] Compared with the prior art, the regeneration method of the palladium catalyst for hydrogen peroxide by the anthraquinone method of the present invention has the following outstanding beneficial effects:

[0033] (1) Thermionic water can activate and clean the soluble substances such as carbonates and phosphates on the catalyst surface; dilute acetic acid can acidify the insoluble aluminum molecules attached to the active center of the catalyst to restore the active channels of the catalyst molecular sieve; ethanol solution can dissolve the organic solvents such as acetic acid, octyl phosphate, anthraquinone, and hydroanthraquinone adhering to the active center of the catalyst; after soaking and rinsing with soft water, all inorganic and organic impurities on the palladium catalyst can be completely removed;

[0034] (2) Under the action of negative pressure and bubbling, the efficiency of solvent soaking and rinsing can be significantly improved, the solvent usage and soaking time can be reduced, thus greatly shortening the regeneration time;

[0035] (3) By adopting in-situ regeneration, the catalyst does not need to be removed from the reactor, which can further shorten the regeneration time and improve the production efficiency of hydrogen peroxide;

[0036] (4) The acetic acid used can effectively dissolve alumina molecules, and acetic acid is a component of the reaction solution in the hydrogen peroxide catalytic reaction, which can avoid introducing other impurities and will not have any impact on the production of hydrogen peroxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Attached Figure 1 is a schematic structural diagram of the reactor in Example 1;

[0038] Attached Figure 2 is Figure 1 the A-A sectional structural diagram of the reactor shown;

[0039] Attached Figure 3 is Figure 1 the B-B sectional structural diagram of the reactor shown;

[0040] Attached Figure 4 is Figure 1 the schematic structural diagram of the purge management of the reactor shown;

[0041] 1. Reactor shell, 2. Purge pipeline, 3. Small holes, 4. Wire mesh. DETAILED DESCRIPTION OF THE INVENTION

[0042] The present invention will be further described below in conjunction with specific embodiments, but it is not intended to limit the present invention.

[0043] Unless otherwise specified, the weighing parts of the raw materials in the following examples are all by volume ratio.

[0044] Example 1

[0045] Regeneration of the catalyst in a 60,000-ton / year hydrogen peroxide production plant.

[0046] As shown in the attached Figures 1-4 figure, 8 The purging pipeline 2 with a length of 8 m. There are small holes 3 opened on the purging pipeline 2 at the axial center position, and there are small holes 3 opened on other purging pipelines 2, and each small hole is arranged at equal intervals along the axial direction of the purging pipeline with a spacing of 2 cm. The purging pipeline 2 is wrapped with a 316 steel wire mesh 4 with a diameter of 100 μm and penetrates through the catalyst bed. During normal production, the inlet and outlet valves of the entire purging pipeline are isolated from the system with blind plates. When the catalyst is reduced, the blind plates are removed and the system is cut in. On the other purging pipelines 2, there are small holes 3 opened, and on each small hole, the purging pipelines are arranged at equal intervals along the axial direction with a spacing of 2 cm. The purging pipeline 2 is wrapped with a 316 steel wire mesh 4 with a diameter of 100 μm and penetrates through the catalyst bed. During normal production, the inlet and outlet valves of the entire purging pipeline are isolated from the system with blind plates. When the catalyst is reduced, the blind plates are removed and the system is cut in.

[0047] Reduction and regeneration process:

[0048] 1) Fill the entire catalyst bed with hot deionized water, soak it, and continuously bubble under the action of 0.5 MPa of superheated saturated steam to activate and clean the soluble substances such as carbonates and phosphates on the catalyst surface. The flow rate of the superheated saturated steam is 30 m 3 / h, the bubbling and soaking time is 45 min, the vacuum degree is -65 KPa. After the steam bubbling is completed, drain the hot deionized water. Repeat this process 1 more time.

[0049] 2) After the hot deionized water soaking is completed and drained, soak the entire catalyst bed with a 30% dilute acetic acid solution, set the N 2 flow rate to 35 m 3 / h, carry out vacuum bubbling, control the vacuum degree at -53 KPa, and soak for 60 min.

[0050] 3) Under the purging action of N 2 drain the liquid in the catalyst bed. Add an 80% ethanol solution to the catalyst bed, adjust the N 2 flow rate to 25 m 3 / h, control the vacuum degree at 37 KPa, soak for 50 min, and completely dissolve the organic solvents such as acetic acid, phosphoric acid octyl ester, anthraquinone, and hydroanthraquinone adhering to the active center of the catalyst.

[0051] 4) Drain the ethanol solution, and under the continuous bubbling of N 2 at a flow rate of 50 m 3 / h and the vacuum pumping at -50 KPa, soak the catalyst bed with hot soft water for 30 min. After draining, rinse the bed with flowing soft water until there are no impurities in the soft water.

[0052] 5) First, purge the bed with N 2 at a flow rate of 50 m 3 / h. After 1 h, purge the catalyst bed with a mixture of N 2 at a flow rate of 40 m 3 / h and H 2 at a flow rate of 10 m 3 / h. Every 30 min, increase the H 2 flow rate by 10 m 3 / h. Wait until N2 After reaching a 1:1 ratio with H 2 purge for 1 h, then every 30 min, N 2 flow rate is reduced by 20 m 3 / h. After 1 h, nitrogen is stopped and hydrogen is used to purge for 1 hour to create a dry reduction atmosphere and complete the catalyst regeneration.

[0053] The maximum regeneration time of this regeneration method is 10 h. The amounts of steam, hot soft water, acetic acid, and ethanol are each about 1 t, which are all less. After regeneration, the effective operation time of the catalyst can reach 13 months, which is basically the same as that of a new catalyst.

[0054] Comparative Example 1:

[0055] Regeneration of the catalyst in a 60,000-ton / year hydrogen peroxide production unit.

[0056] After the catalyst is deactivated, it is soaked in hot soft water, purged with 0.5 MPa steam for 12 h, soaked in aromatic hydrocarbons for 1 hour, and the cycle is repeated 3 times. Then it is hot-washed with steam for 12 h, and N 2 is purged for 8 h. The amount of aromatic hydrocarbons used is about 3 t, and the amount of steam used is large. After regeneration, the effective operation time is 8 - 10 months.

[0057] Example 2:

[0058] Regeneration of the catalyst in a 90,000-ton / year hydrogen peroxide production unit.

[0059] The reactor structure is basically the same as that in Example 1, with the difference that there are 10 purge pipelines with a length of 8 m filled in the catalyst bed.

[0060] Reduction and regeneration process:

[0061] 1) Fill the entire catalyst bed with hot ionized water, soak it, and continuously bubble under the action of 0.5 MPa superheated saturated steam to activate and clean the soluble substances such as carbonates and phosphates on the catalyst surface. The flow rate of the superheated saturated steam is 30 m 3 / h, the bubbling and soaking time is 45 min, the vacuum degree is -78 KPa. After the steam bubbling is completed, the hot ionized water is discharged. Repeat this process 1 more time.

[0062] 2) After the hot ionized water soaking is completed and drained, soak the entire catalyst bed with a 35% dilute acetic acid solution, set the N 2 flow rate to 35 m 3 / h, evacuate and bubble, control the evacuation degree at -55 KPa, and soak for 90 min.

[0063] 3) Under the purging action of N 2 drain the liquid in the catalyst bed. Add an 85% ethanol solution to the catalyst bed and adjust N2 Flow rate: 25 m 3 / h, the vacuum degree is controlled at 33 KPa, soak for 60 min, and completely dissolve organic solvents such as acetic acid, octyl phosphate, anthraquinone, and hydroanthraquinone adhering to the active centers of the catalyst.

[0064] 4) Drain the ethanol solution. Under the continuous bubbling with N 2 50 m 3 / h and the vacuum of -75 KPa, soak the catalyst bed with hot soft water for 45 min. After draining, rinse the bed with flowing soft water until there are no impurities in the soft water.

[0065] 5) Use N 2 Flow rate: 50 m 3 / h to purge the bed. After 1 h, use N 2 Flow rate: 40 m 3 / h and H 2 Flow rate: 10 m 3 / h to mix and purge the catalyst bed. Every 30 min, increase the H 2 Flow rate by 10 m 3 / h. When the ratio of N 2 to H 2 reaches 1:1, purge for 1 h. Then every 30 min, decrease the N 2 Flow rate by 20 m 3 / h. After 1 h, stop the nitrogen and purge with hydrogen for 1 hour to create a dry reduction atmosphere and complete the catalyst regeneration.

[0066] The maximum regeneration time of this regeneration method is 12 h. The amounts of steam, hot soft water, acetic acid, and ethanol are each about 1.5 t, and the amounts used are all small. After regeneration, the effective operation time of the catalyst can reach 12 months, which is basically the same as that of a new catalyst.

[0067] Comparative Example 2:

[0068] Regeneration of the catalyst in a 90,000-ton / year hydrogen peroxide production plant.

[0069] After the catalyst is deactivated, soak it with hot soft water, purge it with 0.5 MPa steam for 12 h, soak it with aromatic hydrocarbons for 1 h, repeat the cycle 3 times, then wash it with steam for 12 h, and purge it with N 2 for 8 h. The amount of aromatic hydrocarbons used is about 4 t, and the amount of steam used is large. After regeneration, the effective operation time is 8 - 10 months.

[0070] Comparative Example 3:

[0071] Regeneration of the catalyst in a 60,000-ton / year hydrogen peroxide production plant.

[0072] The difference from Example 1 is only that:

[0073] In step 2), the entire catalyst bed is soaked in a 90% dilute acetic acid solution.

[0074] The maximum regeneration time of this regeneration method is 10 hours, and the amounts of steam, hot soft water, 90% acetic acid, and ethanol are all about 1 ton each, which are all in small amounts. After regeneration, due to the too high acetic acid concentration, the catalyst skeleton is damaged, and the effective operation time is only 5 months. This comparative example also shows that high-concentration acetic acid has damaged the catalyst skeleton, and highly acidic acids such as nicotinic acid and sulfuric acid will all affect the catalyst skeleton, thus affecting the catalyst activity.

[0075] Comparative Example Four:

[0076] Regeneration of the catalyst for a 90,000-ton / year hydrogen peroxide production unit.

[0077] The difference from Example Two is only that:

[0078] In step 3), a 95% ethanol solution is used.

[0079] The maximum regeneration time of this regeneration method is 12 hours, and the amounts of steam, hot soft water, acetic acid, and 95% ethanol are all about 1.5 tons each, which are all in small amounts. After regeneration, the effective operation time of the catalyst is only 8 months. Due to the corrosion of the catalyst skeleton by high-purity ethanol, pore blockage occurs, affecting the catalytic activity of the catalyst. Other strong organic solvents such as methanol will cause more serious erosion of the catalyst skeleton and are not suitable for cleaning the catalyst.

[0080] Comparative Example Five:

[0081] Regeneration of the catalyst for a 60,000-ton / year hydrogen peroxide production unit.

[0082] The difference from Example One is only that:

[0083] Using N 2 Flow rate 50 m 3 / h to purge the bed. After 3 hours, with N 2 Flow rate 20 m 3 / h and H 2 Flow rate 30 m 3 / h to mix and purge the catalyst bed. After 2 hours, the nitrogen stops, and hydrogen 50 m 3 / h is used to purge for 3 hours to create a dry reduction atmosphere and complete the catalyst regeneration.

[0084] This method first uses nitrogen to purge to create a dry reduction atmosphere, and then uses a large flow rate of hydrogen to purge to create a hydrogen reduction atmosphere. The hydrogen consumption is large. After regeneration, the effective operation time of the catalyst is 9 - 11 months. Compared with Example One and Example Two, the gas consumption is large and the regeneration effect is poor.

[0085] The above embodiments and comparative examples are only compared with the optimal cases selected from all conditions and do not represent all. All research and exploration conducted on the basis of the parallel variation of all data and conditions of the present invention are within the scope of protection.

Claims

1. An anthraquinone process palladium hydrogen peroxide catalyst regeneration method, characterized in that: A purge pipeline is provided on the catalyst bed layer for feeding bubbling gas; The catalyst bed is soaked in hot ionized water, dilute acetic acid, ethanol solution and soft water in turn, and vacuum is drawn during the soaking process, and superheated saturated steam or N2 is used as the bubbling gas for continuous bubbling; The catalyst bed is flushed with soft water and then purged with a purge gas. The purge process gradually reduces the proportion of N2 in the purge gas and increases the proportion of H2.

2. The anthraquinone method for regenerating palladium hydrogen peroxide catalyst according to claim 1, characterized in that: 4 to 20 purge pipelines are arranged on the catalyst bed. The purge height of the purge pipelines is consistent with the catalyst bed height. The tube diameter is φ1=20 to 50 cm. The tube wall is processed with a number of small holes with a diameter of φ2=0.5 to 1.5 cm. The spacing between adjacent small holes is 1.5 to 3 cm.

3. The anthraquinone method for regenerating palladium hydrogen peroxide catalyst according to claim 2, characterized in that: The outside of the purge pipeline is wrapped with a stainless steel wire mesh, and the pore size of the stainless steel wire mesh is 80 to 150 μm.

4. The anthraquinone method for regenerating palladium hydrogen peroxide catalyst according to claim 1, characterized in that: Soak the catalyst bed with hot ionized water for 1 to 3 times, 30 to 60 minutes each time, with a vacuum degree of -100 to -50 KPa, a superheated saturated steam pressure of 0.3 to 0.6 MPa, and a flow rate of 10 to 50 m 3 / h.

5. The anthraquinone method for regenerating palladium hydrogen peroxide catalyst according to claim 1, characterized in that: Soak the catalyst bed with dilute acetic acid 1 to 2 times, each time for 45 to 90 minutes, the concentration of dilute acetic acid is 30% to 60%, the vacuum degree is -70 to -30KPa, and the N2 flow rate is 10 to 30m 3 / h.

6. The anthraquinone method for regenerating palladium hydrogen peroxide catalyst according to claim 1, characterized in that: Soak the catalyst bed with ethanol solution 1-2 times, each time for 30-70 minutes, the concentration of ethanol solution is 70-90%, the vacuum degree is 30-80KPa, and the N2 flow rate is 10-40m 3 / h.

7. The anthraquinone method for regenerating palladium hydrogen peroxide catalyst according to claim 1, characterized in that: Soak the catalyst bed with soft water 1 to 2 times, each time for 10 to 50 minutes, with a vacuum degree of -100 to -50 KPa and a N2 flow rate of 10 to 50 m 3 / h.

8. The anthraquinone method for regenerating palladium hydrogen peroxide catalyst according to claim 1, characterized in that: Rinse the catalyst bed with soft water for 30 to 90 minutes at a flow rate of 10 to 50 m 3 / h of N2 bubbling.

9. The anthraquinone method for regenerating palladium hydrogen peroxide catalyst according to claim 1, characterized in that: The flow rate of the purge gas is 40~60m 3 / h, the mixing ratio of nitrogen and hydrogen in the purge gas is 4:0~0:

4.

10. The anthraquinone method for regenerating palladium hydrogen peroxide catalyst according to claim 9, characterized in that: First, purge with pure N2 for 0.5 to 1.5 hours, then gradually increase the proportion of H2 in the purge gas, and after the ratio of N2 to H2 reaches 1:1, purge for 0.5 to 1.5 hours, then gradually reduce the proportion of N2 in the purge gas, and finally purge with pure H2 for 0.5 to 1.5 hours.

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