Hydrogenation catalyst online washing regeneration method

Abstract

The invention relates to an online washing regeneration method for a hydrogenation catalyst, and belongs to the technical field of catalyst regeneration. The method comprises the following steps: soaking a catalyst bed layer in water, and dissolving impurities such as sulfide capable of being dissolved in water in a catalyst pore channel; then leaching a catalyst bed layer through water to wash out impurities, thereby dredging catalyst pore channels; then, the catalyst bed layer in the hydrogenation reactor is purged by using the activated gas, so that residual water and other volatile components of the catalyst bed layer can be taken away from the hydrogenation reactor, the catalyst bed layer is dried, and oxidized metal on the surface of the catalyst and in pore channels can be reduced into an elemental metal catalyst; therefore, the catalyst in the hydrogenation reactor is regenerated; the whole process does not need to load and unload the catalyst, and is simple to operate, quick to take effect and low in cost.

Description

Technical Field

[0001] The invention relates to the technical field of catalyst regeneration, and in particular to an online water-washing regeneration method for a hydrogenation catalyst. Background Art

[0002] The existing MTBE / butene-1 system includes a hydrogenation unit, an etherification reaction unit and a butene-1 separation unit. The hydrogenation unit uses C4 as a raw material and mixes it with a certain proportion of hydrogen for a selective hydrogenation reaction to remove the 1,3-butadiene inside it.

[0003] In recent years, due to the obvious trend of heavy and inferior raw materials, the raw materials have high sulfur content and many impurities. For example, methyl mercaptan can be adsorbed on the surface of 1,3-butadiene selective hydrogenation catalyst, causing catalyst poisoning and deactivation, resulting in excessive 1,3-butadiene content in the hydrogenated material, resulting in unqualified butene-1 products.

[0004] In the hydrogenation unit of the MTBE / butene-1 system, the 1,3-butadiene selective hydrogenation reactor is a fixed bed without a catalyst regeneration function. Once the catalyst in the hydrogenation reactor is deactivated, even if it is not permanent deactivation, the MTBE / butene-1 system can only be shut down to replace the catalyst in the hydrogenation reactor, which is cumbersome and causes great economic losses. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an online water washing regeneration method for hydrogenation catalysts. The method regenerates the catalyst in the hydrogenation reactor by soaking, leaching and activating. The method has the advantages of low cost, simple operation, quick effect and no need to unload the catalyst.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for online water washing and regeneration of a hydrogenation catalyst comprises the following steps:

[0008] S1, injecting water into the hydrogenation reactor until the water covers the catalyst bed in the hydrogenation reactor, and draining the water after soaking;

[0009] S2, using water to rinse the catalyst bed in the hydrogenation reactor;

[0010] S3, heating the activated gas and passing it into the hydrogenation reactor to purge the catalyst bed.

[0011] In the present invention, the catalyst bed is loaded with a metal catalyst, and the metal catalyst includes at least one of palladium, platinum, nickel, rhodium and ruthenium.

[0012] The present invention first soaks the catalyst bed with water to dissolve the water-soluble impurities such as sulfide in the catalyst pores; then rinses the catalyst bed with water to flush out the impurities, thereby unblocking the catalyst pores; then, the catalyst bed in the hydrogenation reactor is purged with activated gas, which can not only take the residual water and other volatilized components of the catalyst bed away from the hydrogenation reactor, thereby drying the catalyst bed, but also reduce the oxidized metals on the catalyst surface and in the pores to elemental metal catalysts, thereby regenerating the catalyst in the hydrogenation reactor.

[0013] The whole process does not require unloading of the catalyst, is simple to operate, has quick results and is low cost.

[0014] As a preferred embodiment of the present invention, in step S1, the soaking time is 6 to 24 hours, more preferably 12 to 24 hours, and even more preferably 12 to 14 hours.

[0015] The inventors have found that the catalyst bed is soaked before eluting, and the soaking time is preferably 12 to 14 hours. The shorter the soaking time, the higher the economic benefit, and the more soluble impurities in the catalyst bed can be dissolved, effectively improving the activity of the catalyst.

[0016] As a preferred embodiment of the present invention, step S2 specifically includes:

[0017] After the hydrogenation reactor is filled with water, water is injected from the top of the hydrogenation reactor to perform elution treatment on the catalyst bed in the hydrogenation reactor, and water is discharged from the bottom of the hydrogenation reactor;

[0018] When performing the elution treatment in step S2, the inlet and outlet water flow rates are controlled so that the liquid level in the hydrogenation reactor submerges the catalyst bed.

[0019] Furthermore, in step S2, the elution treatment time is 6 to 24 hours, and the water flow rate of the elution treatment is 2 to 3 t / h.

[0020] The inventors have found that during the elution process, the water flow rate of the elution treatment is controlled to be 2-3 t / h, and the elution treatment time is preferably 12-14 hours. The elution time is short, the economic benefit is high, and the impurities in the catalyst bed can be fully washed out, effectively improving the activity of the catalyst.

[0021] As a preferred embodiment of the present invention, in step S1 to step S2, the conductivity of water is not greater than 1 μs / cm.

[0022] Steps S1 to S2 use softened water without ammonia injection.

[0023] As a preferred embodiment of the present invention, step S3 specifically includes:

[0024] S31, heating nitrogen and introducing it from the bottom of the hydrogenation reactor to purge the catalyst bed upwards, and exhausting the tail gas from the top of the reactor;

[0025] S32, nitrogen and hydrogen are mixed and heated, and then introduced into the bottom of the hydrogenation reactor to purge the catalyst bed upwards, and the tail gas is discharged from the top of the reactor.

[0026] The present invention first uses preheated nitrogen to purge the catalyst bed to take away the continuously evaporating water vapor, thereby drying the catalyst bed; then purges with a mixed gas of nitrogen and hydrogen, and the hydrogen reacts with the oxidized metal to generate water and a single metal catalyst, and the water evaporates into water vapor during the purge process and is carried out of the reactor with the purge gas. Optimizing the purge air intake flow rate, the temperature of the catalyst bed and the purge time can effectively improve the activation effect of the catalyst.

[0027] Furthermore, in step S31, the catalyst bed is purged to a temperature of 100 to 250° C. (preferably 150 to 180° C.), and the heated nitrogen is continuously introduced, and the purging is carried out for 8 to 14 hours (preferably 10 to 12 hours).

[0028] In step S31, the flow rate of nitrogen is 100-300 Nm 3 / h, more preferably 150 to 200 Nm 3 / h.

[0029] Furthermore, in step S32, the flow rate of nitrogen is 100-300 Nm 3 / h, the flow rate of hydrogen is 30~100Nm 3 / h, the temperature of the catalyst bed is 100-250°C, and the purge treatment time is 10-18h.

[0030] Furthermore, in step S32, the flow rate of nitrogen is 150-200 Nm 3 / h, the flow rate of hydrogen is 50~80Nm 3 / h, the temperature of the catalyst bed is 150-180°C, and the purge treatment time is 12-14h.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The present invention first soaks the catalyst bed with water to dissolve the water-soluble impurities such as sulfide in the catalyst pores; then rinses the catalyst bed with water to flush out the impurities, thereby unblocking the catalyst pores; then uses activated gas to purge the catalyst bed in the hydrogenation reactor, which can not only take away the residual water and other volatile components in the catalyst bed from the hydrogenation reactor, thereby drying the catalyst bed, but also reduce the oxidized metals on the catalyst surface and in the pores into elemental metal catalysts, thereby regenerating the catalyst in the hydrogenation reactor; the whole process does not require unloading of the catalyst, is simple to operate, has a quick effect, and is low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The present invention provides a process flow chart of the on-line water washing regeneration method for the hydrogenation catalyst. DETAILED DESCRIPTION

[0034] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0035] Unless otherwise specified, the materials and reagents used in the examples can be obtained from commercial sources.

[0036] The softened water used in the following examples and comparative examples has the same source, and the softened water is softened water with a conductivity of less than 1 μs / cm and without ammonia injection.

[0037] Since the better the activity and selectivity of the catalyst, the more butene-1 is produced when the MTBE / butene-1 system is started up, the lower the butene-1 loss rate is, and the content of 1,3-butadiene in the product after the hydrogenation reaction will be reduced, therefore, the present invention uses the butene-1 loss rate and the 1,3-butadiene content in the product to evaluate the activity and selectivity of the catalyst after regeneration.

[0038] The feed and hydrogenation product of the hydrogenation reactor in the system were used as test samples, and the content of butene-1 and the content of 1,3-butadiene were tested in accordance with standard Q / SH 016.03.106-1992.

[0039] The calculation formula for the butene-1 loss rate is as follows: Butene-1 loss rate = w1-w2, where w1 is the butene-1 content in the feed before the hydrogenation reaction, and w2 is the butene-1 content in the product after the hydrogenation reaction.

[0040] Example 1

[0041] The catalyst in the hydrogenation reactor of the hydrogenation unit of the existing MTBE / butene-1 system has been deactivated. The system startup status is as follows:

[0042] The catalyst loaded on the catalyst bed is palladium, and the loading amount of the catalyst in the catalyst bed is 2.3 t. The C4 fraction and hydrogen are simultaneously introduced into the hydrogenation reactor, and the hydrogenation reactor is divided into an upper and lower layer. The hydrogen flow rate of the upper layer of the hydrogenation reactor is 3.78 Kg / h, and the hydrogen flow rate of the lower layer of the hydrogenation reactor is 1.24 Kg / h. The feed flow rate of the C4 fraction is 11 t / h, the inlet temperature of the C4 fraction of the hydrogenation reactor is 57.5°C, the reaction temperature rise is 5.3°C, and the reaction pressure is 1.9 MPa, to obtain a crude hydrogenation product.

[0043] Before feeding, the content of butene-1 in the raw material C4 fraction was sampled and tested, the content of butene-1 and the content of 1,3-butadiene in the product were sampled and tested, and the butene-1 loss rate was calculated. The test results are shown in Table 1.

[0044] This embodiment provides a method for online water washing and regeneration of a hydrogenation catalyst, and its process flow is as follows: Figure 1 The method provided in this embodiment is used to perform water washing and regeneration treatment on the catalyst bed in the above hydrogenation reactor; the online water washing and regeneration method for hydrogenation catalyst comprises the following steps:

[0045] (1) Connect a soft water pump to the top of the hydrogenation reactor 1 through a pipeline, and use the softened water pump to fill the hydrogenation reactor 1 with softened water, so that the catalyst bed in the hydrogenation reactor 1 is immersed in the softened water for 14 hours;

[0046] (2) Open the drain valve at the bottom of the hydrogenation reactor 1, and use a softened water pump to inject softened water at a flow rate of 2.5 t / h to rinse the catalyst bed in the hydrogenation reactor 1. The rinsing water is discharged from the bottom of the hydrogenation reactor 1. The opening of the drain valve is adjusted so that the liquid level in the hydrogenation reactor 1 is above the hydrogenation catalyst bed. After eluting for 12 hours, stop injecting softened water, and close the drain valve after the rinsing water is discharged;

[0047] (3) Connect the pipeline at the outlet of the air pump 2 to the nitrogen delivery pipe and hydrogen delivery pipe of the pipeline network;

[0048] (4) nitrogen is transported to the heater 3 by the air pump 2 for heating. The heated nitrogen is introduced from the bottom of the hydrogenation reactor 1 to purge the catalyst bed, so that the temperature of the catalyst bed is continuously increased. After the temperature of the catalyst bed reaches 180° C., the purge is continued for 10 hours;

[0049] (5) The nitrogen and hydrogen are transported to the heater 3 by the air pump 2 for mixed heating. The heated mixed gas is introduced from the bottom of the hydrogenation reactor 1, the temperature of the catalyst bed is maintained at 180° C., and the catalyst bed is purged for 14 hours.

[0050] In step (4), the flow rate of nitrogen is 150 Nm 3 / h;

[0051] In step (5), the flow rate of nitrogen is 150 Nm 3 / h, the flow rate of hydrogen is 50Nm 3 / h;

[0052] In step (4) and step (5), the purge tail gas is discharged from the top safety valve by-line of the hydrogenation catalyst 1 to the low-pressure gas system.

[0053] After the regeneration treatment, the system was restarted, and the process parameters were the same as before the regeneration. Before feeding, the content of butene-1 in the raw material C4 fraction was sampled and tested, and the content of butene-1 and 1,3-butadiene in the product was sampled and tested, and the butene-1 loss rate was calculated. The test results are shown in Table 1.

[0054] Example 2

[0055] This embodiment provides an online water washing regeneration method for a hydrogenation catalyst. The difference between this embodiment and embodiment 1 is that step (1) of this embodiment is soaking for 6 hours;

[0056] In this example, the butene-1 loss rate and the content of 1,3-butadiene in the product measured before water washing regeneration and after regeneration and restarting are shown in Table 1.

[0057] Example 3

[0058] This embodiment provides an online water washing regeneration method for a hydrogenation catalyst. The difference between this embodiment and embodiment 1 is that step (1) of this embodiment is soaking for 12 hours;

[0059] In this example, the butene-1 loss rate and the content of 1,3-butadiene in the product measured before water washing regeneration and after regeneration and restarting are shown in Table 1.

[0060] Example 4

[0061] This embodiment provides an online water washing regeneration method for a hydrogenation catalyst. The difference between this embodiment and embodiment 1 is that step (1) of this embodiment is soaking for 18 hours;

[0062] In this example, the butene-1 loss rate and the content of 1,3-butadiene in the product measured before water washing regeneration and after regeneration and restarting are shown in Table 1.

[0063] Example 5

[0064] This embodiment provides an online water washing regeneration method for a hydrogenation catalyst. The difference between this embodiment and embodiment 1 is that step (1) of this embodiment is soaking for 24 hours;

[0065] In this example, the butene-1 loss rate and the content of 1,3-butadiene in the product measured before water washing regeneration and after regeneration and restarting are shown in Table 1.

[0066] Example 6

[0067] This embodiment provides an online water washing regeneration method for a hydrogenation catalyst. The difference between this embodiment and embodiment 1 is that step (2) of this embodiment is eluted for 6 hours;

[0068] In this example, the butene-1 loss rate and the content of 1,3-butadiene in the product measured before water washing regeneration and after regeneration and restarting are shown in Table 1.

[0069] Example 7

[0070] This embodiment provides an online water washing regeneration method for a hydrogenation catalyst. The difference between this embodiment and embodiment 1 is that step (2) of this embodiment is eluted for 14 hours;

[0071] In this example, the butene-1 loss rate and the content of 1,3-butadiene in the product measured before water washing regeneration and after regeneration and restarting are shown in Table 1.

[0072] Example 8

[0073] This embodiment provides an online water washing regeneration method for a hydrogenation catalyst. The difference between this embodiment and embodiment 1 is that step (2) of this embodiment is eluted for 18 hours;

[0074] In this example, the butene-1 loss rate and the content of 1,3-butadiene in the product measured before water washing regeneration and after regeneration and restarting are shown in Table 1.

[0075] Example 9

[0076] The present embodiment provides an online water washing regeneration method for a hydrogenation catalyst. The difference between the present embodiment and the embodiment 1 is that the step (2) of the present embodiment is eluted for 24 hours. In the present embodiment, the butene-1 loss rate and the content of 1,3-butadiene in the product measured before water washing regeneration and after regeneration are shown in Table 1.

[0077] Example 10

[0078] This embodiment provides an online water washing regeneration method for a hydrogenation catalyst. The difference between this embodiment and embodiment 1 is that the nitrogen flow rate in step (4) of this embodiment is 200 Nm 3 / h, keep warm and purge at 150°C for 12h; the flow rate of nitrogen in step (5) is 200Nm 3 / h, the flow rate of hydrogen is 80Nm3 / h, maintaining the temperature of the catalyst bed at 150°C, and purging the catalyst bed for 12h;

[0079] In this example, the butene-1 loss rate and the content of 1,3-butadiene in the product measured before water washing regeneration and after regeneration and restarting are shown in Table 1.

[0080] Embodiment 11

[0081] This embodiment provides an online water washing regeneration method for a hydrogenation catalyst. The difference between this embodiment and embodiment 1 is that the nitrogen flow rate in step (4) of this embodiment is 100 Nm 3 / h, keep warm and purge at 100°C for 14h; the flow rate of nitrogen in step (5) is 100Nm 3 / h, the flow rate of hydrogen is 100Nm 3 / h, maintaining the temperature of the catalyst bed at 100°C, and purging the catalyst bed for 10 hours;

[0082] In this example, the butene-1 loss rate and the content of 1,3-butadiene in the product measured before water washing regeneration and after regeneration and restarting are shown in Table 1.

[0083] Example 12

[0084] This embodiment provides an online water washing regeneration method for a hydrogenation catalyst. The difference between this embodiment and embodiment 1 is that the nitrogen flow rate in step (4) of this embodiment is 250 Nm 3 / h, keep warm and purge at 200°C for 10h; the flow rate of nitrogen in step (5) is 150Nm 3 / h, the flow rate of hydrogen is 50Nm 3 / h, maintaining the temperature of the catalyst bed at 200°C, and purging the catalyst bed for 14h;

[0085] In this example, the butene-1 loss rate and the content of 1,3-butadiene in the product measured before water washing regeneration and after regeneration and restarting are shown in Table 1.

[0086] Embodiment 13

[0087] This embodiment provides an online water washing regeneration method for a hydrogenation catalyst. The difference between this embodiment and embodiment 1 is that the nitrogen flow rate in step (4) of this embodiment is 300 Nm 3 / h, keep warm and purge at 250°C for 8h; the flow rate of nitrogen in step (5) is 300Nm 3 / h, the flow rate of hydrogen is 30Nm 3 / h, maintaining the temperature of the catalyst bed at 250°C, and purging the catalyst bed for 16h;

[0088] In this example, the butene-1 loss rate and the content of 1,3-butadiene in the product measured before water washing regeneration and after regeneration and restarting are shown in Table 1.

[0089] Table 1

[0090]

[0091] As can be seen from Table 1, in the embodiment of the present invention, the catalyst bed is first soaked in water, then the catalyst bed is rinsed with water, and the catalyst bed in the hydrogenation reactor is purged with an activated gas, so that the catalyst in the hydrogenation reactor is regenerated, and the activity and selectivity of the catalyst are significantly improved after the regeneration.

[0092] It can be seen from Examples 1 to 5 that the butene-1 loss rate in Example 1 and Example 3 decreased more significantly, and the content of 1,3-butadiene in the hydrogenation product decreased significantly more, which means that after soaking for 12 to 14 hours, the catalyst regeneration effect is better, and the activity and selectivity of the catalyst are improved more significantly.

[0093] The decrease in the butene-1 loss rate and the decrease in the content of 1,3-butadiene in the hydrogenation product in Example 1 and Example 7 are significantly greater than the corresponding decreases in Example 6, but are not much different from the corresponding decreases in Examples 8 to 9. This shows that after eluting for 12 to 14 hours, the catalyst regeneration effect is good, and the activity and selectivity of the catalyst are significantly improved. However, continuing to extend the elution time does not significantly improve the catalyst regeneration effect, but significantly increases the cost.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for online water washing and regeneration of a hydrogenation catalyst, characterized in that: The steps include: S1, injecting water into the hydrogenation reactor until the water covers the catalyst bed in the hydrogenation reactor, and draining the water after soaking; S2, using water to rinse the catalyst bed in the hydrogenation reactor; S3, heating the activated gas and passing it into the hydrogenation reactor to purge the catalyst bed.

2. The on-line water washing regeneration method for hydrogenation catalyst according to claim 1, characterized in that: In step S1, the soaking time is 6 to 24 hours.

3. The on-line water washing regeneration method for hydrogenation catalyst according to claim 1, characterized in that: Step S2 specifically includes: After the hydrogenation reactor is filled with water, the catalyst bed in the hydrogenation reactor is subjected to elution treatment; When performing the elution treatment in step S2, the inlet and outlet water flow rates are controlled so that the liquid level in the hydrogenation reactor submerges the catalyst bed.

4. The on-line water washing regeneration method for hydrogenation catalyst according to claim 3, characterized in that: In step S2, the elution treatment time is 6 to 24 hours, and the water flow rate of the elution treatment is 2 to 3 t / h.

5. The on-line water washing regeneration method for hydrogenation catalyst according to claim 1, characterized in that: In step S1 to step S2, the conductivity of water is not greater than 1 μs / cm.

6. The on-line water washing regeneration method for hydrogenation catalyst according to claim 1, characterized in that: Step S3 specifically includes: S31, heating nitrogen and introducing it from the bottom of the hydrogenation reactor to purge the catalyst bed upwards, and exhausting the tail gas from the top of the reactor; S32, nitrogen and hydrogen are mixed and heated, and then introduced into the bottom of the hydrogenation reactor to purge the catalyst bed upwards, and the tail gas is discharged from the top of the reactor.

7. The on-line water washing regeneration method for hydrogenation catalyst according to claim 6, characterized in that: Step S31: Purge until the temperature of the catalyst bed is 100-250° C., continue to introduce heated nitrogen, and maintain the temperature for 8-14 hours.

8. The on-line water washing regeneration method for hydrogenation catalyst according to claim 6, characterized in that: In step S31, the flow rate of nitrogen is 100-300 Nm 3 / h.

9. The on-line water washing regeneration method for hydrogenation catalyst according to claim 6, characterized in that: In step S32, the flow rate of nitrogen is 100-300 Nm 3 / h, the flow rate of hydrogen is 50~100Nm 3 / h.

10. The method for online water washing and regeneration of hydrogenation catalyst according to claim 6, characterized in that: In step S32, the temperature of the catalyst bed is 100-200°C, and the purge time is 10-18 hours.

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