阅读说明：本技术 一种重整抽余油制备轻质芳烃的开工方法 (Start-up method for preparing light aromatic hydrocarbon by reforming raffinate oil ) 是由 肖哲 潘罗其 张玉红 余卫勋 彭涛 杜建文 刘洪武 于 2019-10-08 设计创作，主要内容包括：本发明属于催化重整技术领域,具体提供一种重整抽余油制备轻质芳烃的开工方法,将催化剂干燥后在低氢分压条件下进行特殊的梯度控温还原,随后再进行高氢分压下的高温还原。该法能够降低催化剂还原过程中水生成速度,大幅度降低还原生成水的高峰值,减少还原过程中生成的水对催化剂的影响,同时降低催化剂反应初期的活性,降低反应物中重芳烃含量,提高催化剂的稳定性,延长催化剂寿命。(The invention belongs to the technical field of catalytic reforming, and particularly provides a start-up method for preparing light aromatic hydrocarbon by reforming raffinate oil. The method can reduce the water generation speed in the catalyst reduction process, greatly reduce the high peak value of the reduced raw water, reduce the influence of the water generated in the reduction process on the catalyst, simultaneously reduce the activity of the catalyst in the initial reaction stage, reduce the content of heavy aromatic hydrocarbon in reactants, improve the stability of the catalyst and prolong the service life of the catalyst.)

1. A start-up method for preparing light aromatic hydrocarbon by reforming raffinate oil is characterized by comprising the following steps:

step (1): drying the catalyst for preparing light aromatic hydrocarbon by reforming raffinate oil under the condition of oxygen-containing gas;

step (2): after the drying of the catalyst is finished, replacing oxygen-containing gas in the system with protective gas, and then introducing hydrogen-containing gas A to perform low-hydrogen partial pressure gradient reduction; then introducing hydrogen-containing gas B for high-temperature reduction of the catalyst;

the hydrogen-containing atmosphere A is a mixed gas of hydrogen and a protective gas, and H₂5-20V%; the hydrogen content of the hydrogen-containing gas B is not lower than 90 percent;

the low hydrogen partial pressure gradient reduction comprises a first stage reduction, a second stage reduction and a third stage reduction which are sequentially carried out; wherein the temperature of the first stage reduction is 260-300 ℃; the temperature of the second-stage reduction is 400-420 ℃; the temperature of the third stage reduction is 470-500 ℃; the pressure in the low hydrogen partial pressure gradient process is 0.1-0.2 MPa, and the volume ratio of the aerosol is 2000-2500;

the temperature in the high-temperature reduction process is 470-500 ℃, the pressure is 0.1-0.2 MPa, and the volume ratio of the air agent is 1200-2000;

and (3): and (3) applying the catalyst treated in the step (2) to catalytic reforming of raffinate oil to prepare light aromatic hydrocarbon.

2. The start-up method for preparing light aromatic hydrocarbons by reforming raffinate oil according to claim 1, wherein the catalyst is an L molecular sieve catalyst loaded with platinum-tin active components.

3. The start-up method for preparing light aromatic hydrocarbons by reforming raffinate oil according to claim 1, wherein the drying conditions in the step (1) are as follows: the temperature is 470-500 ℃, the pressure is 0.1-0.2 MPa, and the volume ratio of the air agent is 2000-2500.

4. The process of claim 1, wherein the oxygen-containing gas is air.

5. The start-up method for preparing light aromatic hydrocarbons by reforming raffinate oil according to claim 1, wherein after the drying in the step (1) is finished, the temperature is reduced to 190-200 ℃, and protective atmosphere is introduced to replace oxygen-containing gas in the protective atmosphere.

6. The start-up method for preparing light aromatic hydrocarbons by reforming raffinate oil according to claim 1, wherein the protective gas is at least one of nitrogen and inert gas.

7. The start-up method for preparing light aromatic hydrocarbons by reforming raffinate oil according to claim 1, wherein in the step (2), the protective gas is replaced until the oxygen content in the system is lower than 0.2V%, then hydrogen-containing gas A is introduced for low hydrogen partial pressure gradient reduction, and hydrogen-containing gas B (high-purity hydrogen) is introduced for high-temperature catalyst reduction.

8. The start-up method for preparing light aromatic hydrocarbons by reforming raffinate oil according to claim 1, wherein the time for the first stage of reduction is 3-5 hours;

the time of the second stage reduction is 3-5 h;

the third stage reduction time is 1-3 h;

the time of the high-temperature reduction process is 1-3 h.

9. The start-up method for preparing light aromatic hydrocarbons by reforming raffinate oil according to any one of claims 1 to 8, wherein in the step (3), the temperature of the catalyst treated in the step (2) is reduced to 360-370 ℃, the reformed raffinate oil is pre-reacted for a period of time at a certain temperature, and then the temperature is raised to the catalytic reaction temperature to catalytically reform raffinate oil to prepare light aromatic hydrocarbons;

or, cooling the catalyst treated in the step (2), reacting with cyclohexane in advance, and then introducing the reformed raffinate oil for catalytic reaction to prepare the light aromatic hydrocarbon.

10. The startup method for preparing light aromatic hydrocarbons by reforming raffinate oil according to claim 9, wherein in the step (3), the treated catalyst is pre-reacted and then subjected to catalytic reaction;

the pre-reaction conditions are as follows: the temperature is 425-435 ℃, the pressure is 0.6-1.0 MPa, the volume ratio of hydrogen and hydrocarbon is 1000-1500, and the airspeed is 2.5-3.5 h^-1The reaction time is 100-200 h.

11. The process of claim 9, wherein the reaction conditions with cyclohexane are as follows: the temperature is 440-460 ℃, the pressure is 0.3-1.0 MPa, the volume ratio of hydrogen and hydrocarbon is 400-1200, and the airspeed is 1.5-3.5 h^-1The reaction time is 100-200 h.

12. The start-up method for preparing light aromatic hydrocarbons by reforming raffinate oil according to any one of claims 1 to 11, wherein in the step (3), the catalytic reaction conditions are as follows: the temperature is 450-520 ℃, the pressure is 0.3-1.0 MPa, the volume ratio of hydrogen to hydrocarbon is 400-1200, and the airspeed is 1.5-3.5 h^-1。

Technical Field

The invention belongs to the technical field of catalytic reforming, and relates to a start-up method for catalytic reforming, in particular to a start-up method for preparing light aromatic hydrocarbon by reforming raffinate oil.

Background

Along with the rapid growth of economy and the rapid development of polyester industry in China, the demand for aromatic hydrocarbon is increasing day by day, so that the production capacity of a catalytic reforming device in China is greatly increased, and the catalytic reforming is mainly used for producing high-octane gasoline and mainly used for producing aromatic hydrocarbon. Besides most of aromatic hydrocarbon, the reforming device also has a considerable part of non-aromatic components, namely, reforming raffinate oil, wherein the reforming raffinate oil accounts for about 30-40% of the reforming generated oil, and the yield of the reforming raffinate oil is increased along with the extension of the reforming device.

At present, the reformed raffinate oil is mainly used as a gasoline blending component or for producing various solvent oils, and a small amount of the reformed raffinate oil is used as an ethylene cracking raw material. The octane number (RON) of the reformed raffinate oil is only 60-70, so that the reformed raffinate oil is limited in addition amount as a gasoline blending component and low in additional value; on the other hand, along with the stricter requirements on environmental protection in China, the reformed raffinate oil mainly contains C5-C7 hydrocarbon, the boiling range is less than or equal to 90 ℃, and the application range of the reformed raffinate oil as solvent oil is limited; and the reformed raffinate oil has high content of isoparaffin, is used as an ethylene cracking raw material, and has lower ethylene yield compared with the straight-run naphtha.

The main components of the reformed raffinate oil are C5-C7 isomeric and normal alkanes, a small amount of cycloalkanes, olefins and aromatics, the octane number is low, but harmful impurities such as sulfur, nitrogen compounds, heavy metals and the like are not contained, the C6-C7 alkanes of the reformed raffinate oil are converted into corresponding light aromatics, and the reformed raffinate oil has great value-added potential.

The inventor introduces a method for preparing aromatic hydrocarbon by reforming raffinate oil in patents CN201510438398 and CN201510438487, a used catalyst is an L molecular sieve catalyst carrying active components such as platinum, tin and the like, the requirements of the catalyst on sulfur and water are very strict, the catalyst is not vulcanized in the start-up process, chlorine is not supplemented in the production process, the conventional catalytic reforming catalyst reduction start-up method is adopted, the service life of the catalyst is short, and the service life of the catalyst is only 5000-8000 hours.

The conventional catalyst reduction start-up method for catalytic reforming is to dry a catalyst, dry the catalyst by air, dry the catalyst by low-oxygen nitrogen and dry the catalyst by high-temperature oxygen-enriched nitrogen, then use high-purity hydrogen to reduce the catalyst at high temperature, then reduce the catalyst to a certain temperature, feed oil, and raise the temperature to a reaction temperature for reforming reaction.

The technology has the problems that during high-temperature reduction, the reduction speed of the metal oxide is high, the water generated by reduction quickly increases the water content in the reduced hydrogen, so that the high peak value of the water content in the reduced hydrogen is too high, the loss of chlorine in the catalyst is accelerated, and the service life of the catalyst is influenced; when the reaction is carried out by directly heating the reaction materials to the reaction temperature, the catalyst has high activity, the content of heavy aromatics in reactants is high, and the service life of the catalyst is influenced by easy coking.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a start-up method for preparing light aromatic hydrocarbon by reforming raffinate oil, which can reduce the water generation speed in the catalyst reduction process, greatly reduce the high peak value of the reduced raw water, reduce the influence of the water generated in the reduction process on the catalyst, simultaneously reduce the activity of the catalyst in the initial reaction stage, reduce the content of heavy aromatic hydrocarbon in reactants, improve the stability of the catalyst and prolong the service life of the catalyst.

In order to achieve the purpose, the invention provides a start-up method for preparing light aromatic hydrocarbon by reforming raffinate oil, which comprises the following steps:

step (1): drying the catalyst for preparing light aromatic hydrocarbon by reforming raffinate oil under the condition of oxygen-containing gas;

step (2): after the drying of the catalyst is finished, replacing oxygen-containing gas in the system with protective gas, and then introducing hydrogen-containing gas A to perform low-hydrogen partial pressure gradient reduction; then introducing hydrogen-containing gas B for high-temperature reduction of the catalyst;

the hydrogen-containing atmosphere A is a mixed gas of hydrogen and a protective gas, and H₂5-20V%; the hydrogen content of the hydrogen-containing gas B is not lower than 90 percent;

the pressure of the low-hydrogen partial pressure gradient reduction is 0.1-0.2 MPa, and the volume ratio of the gas agent is 2000-2500; the method comprises the steps of sequentially carrying out first-stage reduction, second-stage reduction and third-stage reduction; wherein the temperature of the first stage reduction is 260-300 ℃; the temperature of the second-stage reduction is 400-420 ℃; the temperature of the third stage reduction is 470-500 ℃;

the temperature in the high-temperature reduction process is 470-500 ℃, the pressure is 0.1-0.2 MPa, and the volume ratio of the air agent is 1200-2000;

and (3): and (3) applying the catalyst treated in the step (2) to catalytic reforming of raffinate oil to prepare light aromatic hydrocarbon.

The invention innovatively provides a precise gradient temperature control idea of utilizing low hydrogen partial pressure to solve the problem of water vapor in the reduction start-up process of preparing light aromatic hydrocarbon by reforming raffinate oil. Researches show that by matching the accurate gradient temperature control idea of low hydrogen partial pressure with the temperature control mechanism, the water generation speed of the catalyst in the reduction process can be effectively controlled, the high peak value of the reduced raw water is greatly reduced, the influence of the water generated in the reduction process on the catalyst is reduced, the service life of the catalyst is obviously improved, the activity of the catalyst in the initial reaction stage is reduced, the content of heavy aromatics in reactants is reduced, the stability of the catalyst is improved, and the service life of the catalyst is prolonged.

In the invention, the catalyst is an L molecular sieve catalyst loaded with platinum-tin active components.

More preferably, the catalyst is PL-90 of Zhongpetrochemical ChangLing catalyst company.

The oxygen-containing gas is a gas with oxygen content not higher than 40%, such as air.

In the step (1), the L molecular sieve catalyst carrying the platinum-tin active component in an oxidation state is filled into a reactor, and the catalyst is dried after being sealed in a gas-tight manner in the reactor.

Preferably, the drying conditions in step (1) are as follows: the temperature is 470-500 ℃, the pressure is 0.1-0.2 MPa, and the volume ratio of the air agent is 2000-2500. The preferable drying time is 3-5 h.

Preferably, after the drying in the step (1) is finished, cooling to 190-200 ℃, introducing a protective atmosphere, and replacing the oxygen-containing gas.

Preferably, the protective gas is at least one of nitrogen and inert gas.

Preferably, in step (2), the protective gas is replaced until the oxygen content in the system is lower than 0.2V%, then hydrogen-containing gas A is introduced for low hydrogen partial pressure gradient reduction, and hydrogen-containing gas B (high purity hydrogen) is introduced for high temperature reduction of the catalyst.

The protective gas in the hydrogen-containing gas a is at least one of nitrogen and an inert gas.

Preferably, the hydrogen-containing gas A has a hydrogen content of 8 to 15V%.

Preferably, the time of the first stage reduction is 3-5 h.

Preferably, the time of the second stage reduction is 3-5 h.

Preferably, the time of the third stage reduction is 1-3 h.

The hydrogen-containing gas B is preferably high-purity hydrogen (purity of 99.999%).

Preferably, the time of the high-temperature reduction process is 1-3 h.

Preferably, the gradient reduction in step (2) is: reducing the hydrogen-containing nitrogen for 3-5 h at the temperature of 260-300 ℃ under the pressure of 0.1-0.2 MPa and the gas agent volume ratio of 2000-2500; heating to 400-420 ℃, and reducing for 3-5 h; then heating to 470-500 ℃, and reducing for 1-3 h; introducing high-purity hydrogen, and reducing for 1-3 h at the temperature of 470-500 ℃, the pressure of 0.1-0.2 MPa and the volume ratio of the air agent of 1200-2000.

In the invention, after the treatment by the special reduction mechanism, the treated catalyst is used for preparing light aromatic hydrocarbon by reforming raffinate oil.

In the step (3), the temperature of the catalyst treated in the step (2) is reduced to 360-370 ℃, the raffinate oil is reformed, pre-reacted for a period of time at a certain temperature, and then heated to the reaction temperature for normal working condition reaction (catalytic reaction).

In the step (3), the pre-reaction operating conditions are as follows: the temperature is 425-435 ℃, the pressure is 0.6-1.0 MPa, the volume ratio of hydrogen and hydrocarbon is 1000-1500, and the airspeed is 2.5-3.5 h^-1The reaction time is 100-200 h.

Or, in the step (3), the catalyst treated in the step (2) is cooled, is reacted with cyclohexane in advance, and then is introduced into the reformed raffinate oil for catalytic reaction to prepare the light aromatic hydrocarbon.

The invention innovatively discovers that the special start-up means is matched with the cyclohexane pre-reaction means, so that the activity of the catalyst at the initial reaction stage can be further reduced, and the content of heavy aromatic hydrocarbon in reactants can be reduced.

Preferably, the conditions for the reaction with cyclohexane are: the temperature is 440-460 ℃, the pressure is 0.3-1.0 MPa, the volume ratio of hydrogen and hydrocarbon is 400-1200, and the airspeed is 1.5-3.5 h^-1The reaction time is 100-200 h.

In the step (3), the reforming normal working condition is as follows: the temperature is 450-520 ℃, the pressure is 0.3-1.0 MPa, the volume ratio of hydrogen to hydrocarbon is 400-1200, and the airspeed is 1.5-3.5 h^-1。

Advantageous effects

The combined start-up method of gradient reduction and pre-reaction can reduce the water generation speed in the catalyst reduction process, greatly reduce the high peak value of the generated water, reduce the highest water content in the reduction gas to be lower than 80 mu L/L, reduce the influence of the water generated in the reduction process on the catalyst, reduce the activity of the catalyst in the initial reaction stage, reduce the content of heavy aromatics in the reactants in the initial reaction stage, and reduce the content of C in the reactants in the initial reaction stage₉ ⁺The content of heavy aromatics is lower than 0.5 wt%, the stability of the catalyst is improved, the service life of the catalyst is greatly prolonged, and the service life of the catalyst exceeds 13000 h.

Detailed Description

The present invention will be further described with reference to the following examples, but the present invention is not limited thereto.

Example 1

60ml of platinum-containing tin in the oxidized state are takenThe L molecular sieve catalyst PL-90 (produced by Zhongpetrochemical ChangLing catalyst company, active component content is shown in table 1) is put into a 200ml reactor, air is introduced, the pressure is increased to 0.15MPa, the temperature is increased at the speed of 25 ℃/h under the condition that the tail gas amount is 120NL/h, the temperature is kept for 4h at 480 ℃, the temperature is reduced to 200 ℃ at the speed of 35 ℃/h, nitrogen is introduced for replacement until the oxygen content in the system is 0.1V%, then nitrogen containing 12V% of hydrogen is introduced, the temperature is increased to 280 ℃ at the speed of 20 ℃/h under the conditions that the pressure is 0.15MPa and the tail gas amount is 100NL/h, the reduction is carried out for 4h, the temperature is increased to 400 ℃, the reduction is carried out for 2h, the temperature is continuously increased to 480; reducing with high-purity hydrogen for 2h under the conditions of pressure of 0.15MPa and tail gas amount of 80NL/h, wherein the highest value of water content in the tail gas is shown in Table 2; cooling to 370 deg.C at 35 deg.C/h, adjusting hydrogen flow to 200NL/h and pressure to 0.6MPa, feeding 150ml/h of the raw materials into reactor, heating to 435 deg.C, pre-reacting for 100h, and collecting C in the reaction product₉ ⁺The maximum heavy aromatics content is shown in Table 4; then, adjusting to: the reaction temperature is 460 ℃, the pressure is 0.4MPa, the volume ratio of hydrogen to oil is 600:1, and the volume space velocity of the raw material is 2.0h^-1The reaction results are shown in Table 5, the aromatic hydrocarbon content in the reaction product was maintained, the reaction temperature was gradually increased, and the catalyst life was shown in Table 5.

Example 2

Loading 60ml of oxidation state PL-90 catalyst into a 200ml reactor, introducing air, boosting the pressure to 0.10MPa, heating at the rate of 25 ℃/h under the condition of the tail gas amount of 150NL/h, keeping the temperature at 500 ℃ for 3h, cooling at the rate of 35 ℃/h to 200 ℃, introducing nitrogen to replace the oxygen content in the system to be 0.1V%, introducing nitrogen containing 8V% of hydrogen, heating at the rate of 20 ℃/h to 260 ℃ under the conditions of the pressure of 0.10MPa and the tail gas amount of 120NL/h, reducing for 5h, heating to 420 ℃, reducing for 2h, continuing heating to 500 ℃ and reducing for 1 h; reducing by using high-purity hydrogen for 1h under the conditions that the pressure is 0.10MPa and the tail gas quantity is 120NL/h, wherein the highest value of the water content in the tail gas is shown in a table 2; then cooling to 370 ℃ at the speed of 35 ℃/h, adjusting the hydrogen flow to 150NL/h, adjusting the pressure to 0.8MPa, feeding the reformed raffinate oil into the reactor according to the feed flow of 210ml/h, wherein the composition of the used reaction raw materials is shown in Table 3, heating to 425 ℃, carrying out pre-reaction for 200h,c in the reaction product₉ ⁺The maximum heavy aromatics content is shown in Table 4; then, adjusting to: the reaction temperature is 455 ℃, the pressure is 0.35MPa, the volume ratio of hydrogen to oil is 800:1, and the volume space velocity of the raw material is 1.5h^-1The reaction results are shown in Table 5, the aromatic hydrocarbon content in the reaction product was maintained, the reaction temperature was gradually increased, and the catalyst life was shown in Table 5.

Example 3

Loading 60ml of oxidation state PL-90 catalyst into a 200ml reactor, introducing air, boosting the pressure to 0.20MPa, heating at the rate of 25 ℃/h under the condition of tail gas amount of 140NL/h, keeping the temperature at 470 ℃ for 5h, cooling at the rate of 35 ℃/h to 200 ℃, introducing nitrogen to replace the oxygen content in the system to be 0.1V%, introducing nitrogen containing 15V% of hydrogen, heating at the rate of 20 ℃/h to 300 ℃ under the conditions of pressure of 0.20MPa and tail gas amount of 80NL/h, reducing for 3h, heating to 410 ℃, reducing for 2h, continuing heating to 470 ℃ and reducing for 3 h; reducing by using high-purity hydrogen for 3h under the conditions that the pressure is 0.10MPa and the tail gas quantity is 100NL/h, wherein the highest value of the water content in the tail gas is shown in a table 2; cooling to 370 deg.C at 35 deg.C/h, adjusting hydrogen flow to 150NL/h, pressure to 1.0MPa, feeding the reformed raffinate oil into the reactor at 180ml/h feeding rate, wherein the composition of the raw materials is shown in Table 3, heating to 425 deg.C, pre-reacting for 150h, and reacting to obtain the final product C₉ ⁺The maximum heavy aromatics content is shown in Table 4; then, adjusting to: the reaction temperature is 465 ℃, the pressure is 0.6MPa, the volume ratio of hydrogen to oil is 1000:1, and the volume space velocity of the raw material is 3.0h^-1The reaction results are shown in Table 5, the aromatic hydrocarbon content in the reaction product was maintained, the reaction temperature was gradually increased, and the catalyst life was shown in Table 5.

Example 4

Loading 60ml of oxidation state PL-90 catalyst into a 200ml reactor, introducing air, boosting the pressure to 0.15MPa, heating at the rate of 25 ℃/h under the condition of tail gas amount of 120NL/h, keeping the temperature at 480 ℃ for 4h, cooling at the rate of 35 ℃/h to 200 ℃, introducing nitrogen to replace the oxygen content in the system to be 0.1V%, introducing nitrogen containing 10V% of hydrogen, heating at the rate of 20 ℃/h to 280 ℃ under the conditions of pressure of 0.15MPa and tail gas amount of 120NL/h, reducing for 3h, heating to 410 ℃, reducing for 2h, continuing heating to 480 ℃ and reducing for 3 h; instead of using high-purity hydrogen gasReducing for 3h under the conditions that the pressure is 0.15MPa and the tail gas quantity is 120NL/h, wherein the highest value of the water content in the tail gas is shown in a table 2; cooling to 370 deg.C at 35 deg.C/h, adjusting hydrogen flow to 180NL/h, adjusting pressure to 0.8MPa, feeding 150ml/h of reformed raffinate oil into reactor, heating to 430 deg.C, pre-reacting for 150h, and collecting C in reaction product₉ ⁺The maximum heavy aromatics content is shown in Table 4; then, adjusting to: the reaction temperature is 460 ℃, the pressure is 0.4MPa, the volume ratio of hydrogen to oil is 1200:1, and the volume space velocity of the raw material is 2.0h^-1The reaction results are shown in Table 5, the aromatic hydrocarbon content in the reaction product was maintained, the reaction temperature was gradually increased, and the catalyst life was shown in Table 5.

Example 5

60ml of L molecular sieve catalyst PL-90 (produced by Zhongpetrochemical ChangLing catalyst company, and the content of active components is shown in table 1) containing platinum and tin in an oxidation state is loaded into a 200ml reactor, air is introduced, the pressure is increased to 0.15MPa, the temperature is increased at the speed of 25 ℃/h under the condition that the tail gas amount is 120NL/h, the temperature is kept for 4h at 480 ℃, the temperature is reduced to 200 ℃ at the speed of 35 ℃/h, nitrogen is introduced to replace the oxygen content in the system to be 0.1V%, then nitrogen containing 12V% hydrogen is introduced, the temperature is increased to 280 ℃ at the speed of 20 ℃/h under the conditions that the pressure is 0.15MPa and the tail gas amount is 100NL/h, the reduction is carried out for 4h, the temperature is increased to 400 ℃, the reduction is carried out for 2h, the temperature is; reducing with high-purity hydrogen for 2h under the conditions of pressure of 0.15MPa and tail gas amount of 80NL/h, wherein the highest value of water content in the tail gas is shown in Table 2; cooling to 370 deg.C at 35 deg.C/h, adjusting hydrogen flow to 100NL/h and pressure to 0.4MPa, feeding cyclohexane into the reactor at a feeding rate of 120ml/h, heating to 450 deg.C, reacting for 120h to obtain reaction product C₉ ⁺The maximum heavy aromatics content is shown in Table 4; then the reaction material reforming raffinate oil is adjusted, the composition of the reforming raffinate oil is shown in Table 3, the reaction temperature is 450 ℃, the pressure is 0.4MPa, the volume ratio of hydrogen to oil is 600:1, and the volume space velocity of the raw material is 2.0h^-1The reaction results are shown in Table 5, the aromatic hydrocarbon content in the reaction product was maintained, the reaction temperature was gradually increased, and the catalyst life was shown in Table 5.

Example 6

60ml of an oxidation state PL-90 catalyst was charged into a 200ml reactorIntroducing air, boosting the pressure to 0.10MPa, raising the temperature at a rate of 25 ℃/h under the condition that the tail gas amount is 150NL/h, keeping the temperature at 500 ℃ for 3h, lowering the temperature to 200 ℃ at a rate of 35 ℃/h, introducing nitrogen to replace until the oxygen content in the system is 0.1V%, introducing nitrogen containing 8V% of hydrogen, raising the temperature to 260 ℃ at a rate of 20 ℃/h under the conditions that the pressure is 0.10MPa and the tail gas amount is 120NL/h, reducing for 5h, raising the temperature to 420 ℃ again, reducing for 2h, continuously raising the temperature to 500 ℃ and reducing for 1 h; reducing by using high-purity hydrogen for 1h under the conditions that the pressure is 0.10MPa and the tail gas quantity is 120NL/h, wherein the highest value of the water content in the tail gas is shown in a table 2; cooling to 370 deg.C at 35 deg.C/h, adjusting hydrogen flow to 150NL/h and pressure to 0.35MPa, adding cyclohexane at 90ml/h, heating to 460 deg.C, reacting for 200h to obtain reaction product C₉ ⁺The maximum heavy aromatics content is shown in Table 4; then the reaction material reforming raffinate oil is adjusted, the composition of the reforming raffinate oil is shown in Table 3, the reaction temperature is 460 ℃, the pressure is 0.35MPa, the volume ratio of hydrogen to oil is 800:1, and the volume space velocity of the raw material is 1.5h^-1The reaction results are shown in Table 5, the aromatic hydrocarbon content in the reaction product was maintained, the reaction temperature was gradually increased, and the catalyst life was shown in Table 5.

Example 7

Loading 60ml of oxidation state PL-90 catalyst into a 200ml reactor, introducing air, boosting the pressure to 0.20MPa, heating at the rate of 25 ℃/h under the condition of tail gas amount of 140NL/h, keeping the temperature at 470 ℃ for 5h, cooling at the rate of 35 ℃/h to 200 ℃, introducing nitrogen to replace the oxygen content in the system to be 0.1V%, introducing nitrogen containing 15V% of hydrogen, heating at the rate of 20 ℃/h to 300 ℃ under the conditions of pressure of 0.20MPa and tail gas amount of 80NL/h, reducing for 3h, heating to 410 ℃, reducing for 2h, continuing heating to 470 ℃ and reducing for 3 h; reducing by using high-purity hydrogen for 3h under the conditions that the pressure is 0.10MPa and the tail gas quantity is 100NL/h, wherein the highest value of the water content in the tail gas is shown in a table 2; cooling to 370 deg.C at 35 deg.C/h, adjusting hydrogen flow to 200NL/h and pressure to 0.8MPa, feeding cyclohexane into the reactor at a feeding rate of 180ml/h, heating to 440 deg.C, reacting for 100h, and adding C in the reaction product₉ ⁺The maximum heavy aromatics content is shown in Table 4; then the reaction material is adjusted to be reformed raffinate oil, the composition of the reformed raffinate oil is shown in Table 3, the reaction temperature is 440 ℃, the pressure is 0.8MPa, and hydrogen is addedThe oil volume ratio is 1000:1, and the space velocity of the volume of the raw material is 3.0h^-1The reaction results are shown in Table 5, the aromatic hydrocarbon content in the reaction product was maintained, the reaction temperature was gradually increased, and the catalyst life was shown in Table 5.

Example 8

Loading 60ml of oxidation state PL-90 catalyst into a 200ml reactor, introducing air, boosting the pressure to 0.15MPa, heating at the rate of 25 ℃/h under the condition of tail gas amount of 120NL/h, keeping the temperature at 480 ℃ for 4h, cooling at the rate of 35 ℃/h to 200 ℃, introducing nitrogen to replace the oxygen content in the system to be 0.1V%, introducing nitrogen containing 10V% of hydrogen, heating at the rate of 20 ℃/h to 280 ℃ under the conditions of pressure of 0.15MPa and tail gas amount of 120NL/h, reducing for 3h, heating to 410 ℃, reducing for 2h, continuing heating to 480 ℃ and reducing for 3 h; reducing by using high-purity hydrogen for 3h under the conditions that the pressure is 0.15MPa and the tail gas quantity is 120NL/h, wherein the highest value of the water content in the tail gas is shown in a table 2; cooling to 370 deg.C at 35 deg.C/h, adjusting hydrogen flow to 150NL/h and pressure to 0.4MPa, feeding cyclohexane into the reactor at 1150ml/h, heating to 455 deg.C, reacting for 150h, and adding C in the reaction product₉ ⁺The maximum heavy aromatics content is shown in Table 4; then the reaction material reforming raffinate oil is adjusted, the composition of the reforming raffinate oil is shown in Table 3, the reaction temperature is 455 ℃, the pressure is 0.4MPa, the volume ratio of hydrogen to oil is 1200:1, and the volume space velocity of the raw material is 2.0h^-1The reaction results are shown in Table 5, the aromatic hydrocarbon content in the reaction product was maintained, the reaction temperature was gradually increased, and the catalyst life was shown in Table 5.

Comparative example 1

60ml of oxidation state PL-90 catalyst is loaded into a 200ml reactor, nitrogen is introduced to replace the oxygen content in the system to be 0.1V%, high-purity hydrogen is introduced, the pressure is increased to 0.15MPa, the temperature is increased at the rate of 25 ℃/h under the condition that the tail gas amount is 120NL/h, the temperature is reduced for 2h at 480 ℃, and the highest value of the water content in the tail gas is shown in Table 2; then the temperature is reduced to 370 ℃ at the speed of 35 ℃/h, the reformed raffinate oil is fed into the reactor, the composition of the used reaction raw materials is shown in the table 3, and then the reaction raw materials are adjusted to: the reaction temperature is 460 ℃, the pressure is 0.35MPa, the volume ratio of hydrogen to oil is 800:1, and the volume space velocity of the raw material is 1.5h^-1C in the initial reaction₉ ⁺The maximum content of heavy aromatics is shown in Table 4, the reaction results are shown in Table 5,the aromatic content in the reaction product was maintained and the reaction temperature was gradually increased, the catalyst life of which is shown in Table 5.

Comparative example 2

60ml of oxidation state PL-90 catalyst is loaded into a 200ml reactor, nitrogen is introduced to replace the oxygen content in the system to be 0.1V%, high-purity hydrogen is introduced, the pressure is increased to 0.40MPa, the temperature is increased at the rate of 25 ℃/h under the condition that the tail gas quantity is 150NL/h, the temperature is reduced for 2h at the temperature of 500 ℃, and the highest value of the water content in the tail gas is shown in Table 2; then the temperature is reduced to 370 ℃ at the speed of 35 ℃/h, the reformed raffinate oil is fed into the reactor, the composition of the used reaction raw materials is shown in the table 3, and then the reaction raw materials are adjusted to: the reaction temperature is 455 ℃, the pressure is 0.40MPa, the volume ratio of hydrogen to oil is 600:1, and the volume space velocity of the raw material is 2.0h^-1C in the initial reaction₉ ⁺The maximum content of heavy aromatics is shown in Table 4, the reaction results are shown in Table 5, the aromatic content in the reaction product is maintained, the reaction temperature is gradually increased, and the catalyst life is shown in Table 5.

Comparative example 3

60ml of oxidation state PL-90 catalyst is loaded into a 200ml reactor, air is introduced, the pressure is increased to 0.20MPa, the temperature is increased at the rate of 25 ℃/h under the condition of tail gas amount of 140NL/h, the temperature is kept constant for 5h at 470 ℃, the temperature is reduced to 200 ℃ at the rate of 35 ℃/h, nitrogen is introduced to replace the oxygen content in the system to be 0.1V%, then nitrogen containing 15V% of hydrogen is introduced, the temperature is increased to 300 ℃ at the rate of 20 ℃/h under the conditions of pressure of 0.20MPa and tail gas amount of 150NL/h, the reduction is carried out for 3h, the temperature is increased to 480 ℃, the reduction is carried out for 2h, and the highest value of the water content in the tail gas; then the temperature is reduced to 370 ℃ at the speed of 35 ℃/h, the reformed raffinate oil is fed into the reactor, the composition of the used reaction raw materials is shown in the table 3, and then the reaction raw materials are adjusted to: the reaction temperature is 455 ℃, the pressure is 0.40MPa, the volume ratio of hydrogen to oil is 600:1, and the volume space velocity of the raw material is 2.0h^-1C in the initial reaction₉ ⁺The maximum content of heavy aromatics is shown in Table 4, the reaction results are shown in Table 5, the aromatic content in the reaction product is maintained, the reaction temperature is gradually increased, and the catalyst life is shown in Table 5.

Comparative example 4

60ml of oxidation state PL-90 catalyst is loaded into a 200ml reactor, air is introduced, the pressure is increased to 0.20MPa, the temperature is increased at the speed of 25 ℃/h under the condition that the tail gas quantity is 140NL/h, and the temperature is controlled at the temperature ofKeeping the temperature at 470 ℃ for 5h, reducing the temperature to 200 ℃ at the speed of 35 ℃/h, introducing nitrogen for replacement until the oxygen content in the system is 0.1V%, then introducing nitrogen containing 15V% hydrogen, heating to 220 ℃ at the speed of 20 ℃/h under the conditions that the pressure is 0.20MPa and the tail gas quantity is 150NL/h, reducing for 3h, heating to 450 ℃, reducing for 2h, continuously heating to 500 ℃, and reducing for 2 h; the maximum value of the water content in the tail gas is shown in table 2; then the temperature is reduced to 370 ℃ at the speed of 35 ℃/h, the reformed raffinate oil is fed into the reactor, the composition of the used reaction raw materials is shown in the table 3, and then the reaction raw materials are adjusted to: the reaction temperature is 455 ℃, the pressure is 0.40MPa, the volume ratio of hydrogen to oil is 600:1, and the volume space velocity of the raw material is 2.0h^-1C in the initial reaction₉ ⁺The maximum content of heavy aromatics is shown in Table 4, the reaction results are shown in Table 5, the aromatic content in the reaction product is maintained, the reaction temperature is gradually increased, and the catalyst life is shown in Table 5.

TABLE 1 PL-90 catalysts for each active component content

	Pt	Sn	Cl
				Element content, wt%	0.78	1.12	1.25

TABLE 2 example PL-90 catalyst reduction gas maximum Water content

Note: in Table 2, a indicates the highest water content in the catalyst reducing gas.

The method for testing the water content in the catalyst reducing gas comprises the following steps: and testing the dew point of the discharged tail gas by using an online dew point meter on the discharged tail gas of the device, and checking the water content in the tail gas according to the dew point and a water content comparison table.

TABLE 3 reformate PONA composition

Table 4 example C in the reaction product₉ ⁺Maximum heavy aromatics content

Note: in Table 4, b refers to the highest content of C9+ heavy aromatics.

Table 5 example reaction results

Note: in table 5, c is the benzene yield; d is the average yield of toluene.

e is the catalyst life: the life of the catalyst may be measured using methods known in the industry, for example: keeping the yield of the reaction aromatic hydrocarbon at 65-60% at a reaction temperature in a catalyst aromatization reaction temperature interval, recording the reaction time at the reaction temperature, raising the temperature according to a gradient of 5 ℃ when the yield of the aromatic hydrocarbon is lower than 60%, further recording the time when the yield of the aromatic hydrocarbon is higher than 60% at the temperature after the gradient temperature rise, and continuously calculating the total time when the yield is higher than 60% in the aromatization reaction temperature interval (450-520 ℃) in sequence according to the temperature rise gradient, namely the service life of the catalyst.

The data shown in tables 2, 4 and 5 show that the start-up method of gradient reduction and pre-reaction can reduce the water generation speed in the catalyst reduction process, greatly reduce the high peak value of the reduced raw water, reduce the influence of the water generated in the reduction process on the catalyst, improve the stability of the catalyst and greatly prolong the service life of the catalyst.