CN113019270B

CN113019270B - Liquid-phase nitrobenzene hydrogenation catalyst circulation process and device thereof

Info

Publication number: CN113019270B
Application number: CN202110316974.0A
Authority: CN
Inventors: 高洪东; 冷丰强
Original assignee: Individual
Current assignee: Anhui Yingteli Industrial Engineering Technology Co ltd
Priority date: 2021-03-25
Filing date: 2021-03-25
Publication date: 2022-10-28
Anticipated expiration: 2041-03-25
Also published as: CN113019270A

Abstract

The invention relates to a liquid-phase nitrobenzene hydrogenation catalyst circulation process and a device thereof, which is characterized in that: the process comprises catalyst circulation at the initial start-up stage, catalyst slurry temperature rise, nitrobenzene feeding, catalyst tar filtering, material recovery of a catalyst feeding tank (104) and automatic control; the device comprises a reactor (101), a catalyst heater (106), a catalyst feeding tank (104) and a condenser (105), and is characterized in that: the system also comprises a catalyst circulation tank (201), a catalyst cooler (202), a catalyst circulation pump (203), a catalyst filtrate pump (204) and a control system. Can realize the catalyst cycle operation in the initial stage of driving to provide big buffering space, both reduced the operating variable in the initial stage of driving, be favorable to the steady operation of reactor again, thereby improved the security of device. The catalyst heating process at the initial stage of starting is provided, and the stable temperature rise of the reactor is facilitated. And a heat recovery process is provided, and in the normal use process, the catalyst is cooled and cooled while heat is recovered.

Description

Liquid-phase nitrobenzene hydrogenation catalyst circulation process and device thereof

Technical Field

The invention relates to chemical equipment, in particular to aniline manufacturing, and discloses a liquid-phase nitrobenzene hydrogenation catalyst circulation process and a device thereof.

Background

The liquid-phase nitrobenzene hydrogenation catalyst circulation process in the prior art is shown in figures 1-3: high-pressure hydrogen enters a reactor 101 through a pipeline 1, nitrobenzene is added through a pipeline 2, a recycled catalyst is added through a pipeline 3, the two are mixed and then enter the reactor 101 through a pipeline 4, the reactor 101 is an extrusion flow reactor, the catalyst flows from the lower part to the upper part of the reactor 101 in an extrusion flow manner, during the flowing process, the nitrobenzene and the hydrogen react on the catalyst to generate aniline, the reaction is an exothermic reaction, and the released heat is taken away by quenching water added into the reactor 101 through a pipeline 5; when the catalyst flows to the first tower plate of the reactor 101, nitrobenzene is completely reacted to generate aniline, a vaporization space is arranged above the first tower plate, and the aniline and water are vaporized and mixed with excessive hydrogen at the vaporization space, discharged from the top of the reactor in a gaseous form through a pipeline 6, and enter subsequent cooling, separation and other processes; above the first tower plate, the solid catalyst and heavy component tar are not vaporized, and are mixed with aniline, water, a small amount of hydrogen and the like, the mixed material enters a degassing tank 102 through an overflow pipeline 7, gas-liquid separation is carried out, gas returns to a reactor 101 through a communicating pipe 8 at the top of the degassing tank 102, and the liquid phase material mixed with the solid catalyst is cooled to 90 ℃ through an air cooler 103 through a lower pipeline 9 and then enters a catalyst feeding tank 104 through a pipeline 10; before the liquid phase material enters the catalyst feeding tank 104, an automatic valve V101 is arranged for regulating the flow rate of the liquid phase material, the flow rate is displayed by a flow meter F101, and the automatic valve V101 and the liquid level L101 of the degassing tank 102 form a regulating loop for controlling the liquid level of the degassing tank 102 so as to control the stability of a vaporization interface of the reactor; a part of the material containing the catalyst in the catalyst feeding tank 104 enters a catalyst filter pump 107 through a pipeline 11, the material at the outlet of the catalyst filter pump 107 is divided into two parts, one part enters a catalyst filter device through a pipeline 12, an automatic valve V104 and a flow meter F104 are arranged to form a regulating loop, the other part returns to the catalyst feeding tank 104 through a pipeline 13, and the reflux of the part has two ways, one way is that the material directly returns to the catalyst feeding tank 104 through a pipeline 14, and the other way is that the material enters a catalyst heater 106 through a pipeline 15, is heated by the catalyst heater 106 and then returns to the catalyst feeding tank 104; the other part of the material containing the catalyst in the catalyst feeding tank 104 enters a catalyst feeding pump 108 through a pipeline 16, the material at the outlet of the catalyst feeding pump 108 is divided into two parts, one part of the material returns to the catalyst feeding tank 104 through a pipeline 17, and an automatic valve V102 is arranged on the pipeline 17 and used for adjusting the total flow F102 at the outlet of the catalyst feeding pump 108; the other part of the material at the outlet of the catalyst feeding pump 108 is mixed with nitrobenzene through a pipeline 3 and then is pumped into the reactor 101 to participate in the reaction, and an automatic valve V103 and a flow meter F103 are arranged on the pipeline 3 to form a regulating loop; aniline feed containing fresh catalyst is added at the inlet of catalyst feed pump 108 via line 18 to replenish the catalyst consumption of the reaction system; the filtered catalyst is returned to the catalyst feed tank 104 through a pipeline 19 after removing heavy components contained in the catalyst, meanwhile, crude aniline is added through a pipeline 20, the pipeline 20 is provided with an automatic valve V105 and a flowmeter F105, the automatic valve V105 and the liquid level L102 of the catalyst feed tank 104 form a regulating loop for controlling the liquid level of the catalyst feed tank 104, and the flowmeter F105 is used for displaying the flow rate of supplemented crude aniline; the catalyst feed tank 104 contains gases such as water vapor, nitrogen, hydrogen, etc., and a small amount of non-condensable gas is discharged from a safe portion through a line 21 after being condensed and recovered by a top condenser 105.

The device structure used in the liquid phase nitrobenzene hydrogenation catalyst circulation process in the prior art is as follows: it includes reactor 101, degassing tank 102, catalyst feed tank 104, air cooler 103, catalyst filter pump 107, catalyst heater 106, catalyst feed pump 108 and condenser 105, reactor 101 sets gradually nitrobenzene import, first quench water import, hydrogen import, second quench water import, first overflow export and the import of being linked together with gas from lower to upper, reactor 101 top sets up the gas phase export, degassing tank 102 bottom sets up the liquid phase export, the top sets up gaseous phase intercommunication export, the centre sets up the overflow import, catalyst feed tank 104 sets gradually catalyst export, first backward flow import, second backward flow import, liquid phase import and first entry from lower to upper, catalyst feed tank 104 top sets up condenser 105 and intercommunication, reactor 101's nitrobenzene inlet connecting line 4 and through pipeline 2 and nitrobenzene system intercommunication, a first quenching water inlet and a second quenching water inlet of the reactor 101 are simultaneously communicated with a quenching water system through a pipeline 5, a hydrogen inlet of the reactor 101 is communicated with the hydrogen system through a pipeline 1, a first overflow outlet of the reactor 101 is communicated with an overflow inlet of the degassing tank 102 through a pipeline 7, a gas-phase communication inlet of the reactor 101 is communicated with a gas-phase communication outlet of the degassing tank 102 through a communicating pipe 8, a gas-phase outlet of the reactor 101 is communicated with a subsequent condensation-separation system through a pipeline 6, a liquid-phase outlet of the degassing tank 102 is connected with an inlet of the air cooler 103 through a pipeline 9, an outlet of the air cooler 103 is connected with a liquid-phase inlet of the catalyst feed tank 104 through a pipeline 10, a catalyst outlet of the catalyst feed tank 104 is connected with an inlet of a catalyst feed pump 108 through a pipeline 16 and is simultaneously connected with an inlet of a catalyst filter pump 107 through a pipeline 11, the outlet of the catalyst feed pump 108 is connected with the nitrobenzene inlet of the reactor 101 through the pipeline 4 after merging with the pipeline 2 through the pipeline 3, the outlet of the catalyst feed pump 108 is also connected with the second reflux inlet of the catalyst feed tank 104 through the pipeline 17, the outlet of the catalyst filter pump 107 is connected with the catalyst filtering device inlet through the pipeline 12, the outlet of the catalyst filter pump 107 is also provided with the pipeline 13, the pipeline 13 is simultaneously communicated with the pipeline 14 and the pipeline 15, the pipeline 14 is connected with the first reflux inlet of the catalyst feed tank 104, the pipeline 15 is connected with the catalyst inlet of the catalyst heater 106, the catalyst outlet of the catalyst heater 106 is connected with the first reflux inlet of the catalyst feed tank 104, the steam channel of the catalyst heater 106 is connected with the steam system, the first inlet of the catalyst feed tank 104 is communicated with the outlet of the catalyst filtering device through the pipeline 19, the gas phase outlet at the top of the condenser 105 is emptied through the pipeline 21, the cooling water pipeline of the condenser 105 is connected with the cooling water system, the new catalyst system is connected with the inlet of the catalyst feed pump 108 through the pipeline 18, and the catalyst inlet of the catalyst feed tank 104 of the crude aniline system is simultaneously connected with the catalyst feed tank 106 and the first reflux inlet of the catalyst tank 104 through the pipeline 20; an automatic valve V101 is arranged on the pipeline 10 and used for adjusting the flow of liquid phase materials, the flow is displayed by a flow meter F101, and the automatic valve V101 and the liquid level L101 of the degassing tank 102 form an adjusting loop and are used for controlling the liquid level of the degassing tank 102; an automatic valve V104 and a flowmeter F104 are arranged on the pipeline 12 to form a regulating loop; an automatic valve V102 is provided on the line 17 for regulating the total outlet flow F102 of the catalyst feed pump 108; an automatic valve V103 and a flow meter F103 are arranged on the pipeline 3 to form a regulating loop; an automatic valve V105 and a flow meter F105 are arranged on the pipeline 20; see fig. 1-3.

There are problems in that: (1) the fluctuation of the vaporization interface in the reactor 101 is large, which results in unstable flow of the liquid material flowing into the degassing tank 102, while the degassing tank 102 has a small volume and limited buffering capacity, and in practical use, the degassing tank 102 is often in a full liquid level state or a liquid level-free state, which does not play a role in monitoring and buffering, and the automatic valve V101 cannot automatically adjust the liquid level. (2) Catalyst circulation cannot be realized at the initial stage of start-up. The catalyst circulation process is reactor 101-degassing vessel 102-air cooler 103-catalyst feed vessel 104-catalyst feed pump 108-reactor 101, and the orifice of the reactor 101 through which the catalyst-containing material enters degassing vessel 102 is located only one position above the first tray. In the operation of starting the reactor, the catalyst circulation should be established first, so that the liquid level in the reactor 101 will be at the pipe orifice where the reactor 101 is connected with the degassing tank 102, i.e. the evaporation interface, when nitrobenzene and hydrogen are added for reaction, because the reaction process is very violent, the liquid material in the reactor 101 is not vaporized timely, and will enter the pipeline 6 from the top gas phase outlet to flush out, which causes the pressure of the reactor 101 to fluctuate violently, which leads to safety accidents, or the catalyst is lost from the top. Therefore, the current process cannot realize the circulation of the catalyst during the driving. (3) The operation variables are more at the initial stage of driving, the operation process is complex and is not easy to control. After the hydrogen is added, the catalyst cannot be circulated, so the catalyst and the nitrobenzene can only be added into the reactor 101 at the same time, and because the initial temperature is low, the reaction rate is low, the temperature rise is slow, and a large amount of nitrobenzene is accumulated in the reactor 101 in the process. The temperature of reactor 101 is controlled through adding quench water, because when just beginning to add nitrobenzene, reactor 101 temperature is low, if the quench water that adds is too early, will lead to reactor 101 to heat up more slowly, and the accumulation nitrobenzene is more, treats that temperature rising, reaction rate increase back, and reactor 101 temperature can rise sharply, reaches uncontrollable degree, easily causes the incident. If the quench water is added too late, it will also cause the temperature of the reactor 101 to rise dramatically, to an uncontrolled extent. Therefore, the key control variables of the process comprise three variables of nitrobenzene flow, catalyst flow and quench water flow, and the process is complex to operate and difficult to control.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the liquid-phase nitrobenzene hydrogenation catalyst circulation process and the device thereof overcome the defects of the prior art, provide a large buffer space, reduce the operation variables at the initial start-up stage and are beneficial to the stable operation of the reactor 101. The catalyst heating process at the initial start-up stage is provided, which is favorable for the stable temperature rise of the reactor 101. And a heat recovery process is provided, and in the normal use process, the catalyst is cooled and cooled, and meanwhile, heat is recovered.

One of the solutions to the technical problem of the present invention is: a liquid-phase nitrobenzene hydrogenation catalyst circulation process is characterized in that: the method comprises the steps of catalyst circulation at the initial startup, catalyst slurry temperature rise, nitrobenzene feeding, catalyst tar filtering, material recovery of a catalyst feeding tank 104 and automatic control, and specifically comprises the following steps:

1) Catalyst circulation at initial start-up

(1) Starting a catalyst circulating pump 203, wherein catalyst slurry in a catalyst circulating tank 201 firstly flows out of the catalyst circulating tank 201 through a catalyst cooler 202 and then enters the catalyst circulating pump 203 through a pipeline 22, a material at the outlet of the catalyst circulating pump 203 is divided into two parts, one part of the material returns to the catalyst circulating tank 201 through a pipeline 23, and an automatic valve V201 arranged on the pipeline 23 controls the total flow F201 at the outlet of the catalyst circulating pump 203 to be 10-30t/h; the other part of the materials are pumped into the reactor 101 through a pipeline 24, an automatic valve V202 and a flowmeter F202 arranged on the pipeline 24 form a regulating loop, and the flow of the pipeline 24 is controlled to be 10-20t/h;

(2) opening an automatic valve V206 arranged on a pipeline 25 in the middle of the reactor 101 to enable the catalyst slurry in the reactor 101 to overflow into the catalyst circulation tank 201 to realize catalyst circulation;

(3) if the catalyst slurry in the catalyst circulation tank 201 is not enough to realize circulation, the original catalyst feed tank 104 is used as a catalyst filtrate tank, and the catalyst slurry in the catalyst feed tank is supplemented to the catalyst circulation tank 201 by a catalyst filtrate pump 204 to realize catalyst circulation;

(4) if the catalyst slurry in the catalyst feed tank 104 is still insufficient to achieve catalyst circulation, the catalyst feed tank 104 is replenished with crude aniline via line 20 provided on the catalyst feed tank 104;

(5) the main control parameters of the process are that the liquid level L201 of the catalyst circulating tank 201 is controlled to be 10-30%, and the liquid level L102 of the catalyst feeding tank 104 is controlled to be 20-80%;

2) Catalyst slurry temperature rise

(1) Adding hydrogen to the reactor through line 1 and controlling the top pressure of reactor 101 to be 1.6-1.8MPa (g); the flow meter F202 and the automatic valve V202 arranged on the outlet pipeline 24 of the catalyst circulating pump 203 control the flow of the inflow pipeline 24 to be 10 to 20t/h;

(2) hot water is introduced into a catalyst cooler 202 arranged in the catalyst circulation tank 201 through a hot water pipeline 33, the temperature of catalyst slurry at the lower part of the catalyst cooler 202 is heated to 50-80 ℃, and the hot water after heat exchange and cooling of the catalyst cooler 202 returns to a hot water system through a pipeline 34;

(3) the adjustment process for introducing hot water into the catalyst cooler 202 is as follows: an automatic valve V205 and a flow meter F205 arranged on the hot water pipeline 33 and the temperature T201 at the lower part of the catalyst cooler 202 form a regulating loop, the flow meter F205 indicates the added hot water amount, the hot water temperature is 80-110 ℃, and the flow rate is 5-20T/h;

(4) gradually raising the temperature of the circulating catalyst slurry to 50-80 ℃ through the circulation of the catalyst circulating pump 203;

3) Nitrobenzene charging

(1) Nitrobenzene is fed into the reactor 101 through the line 2 provided, and mixed with the catalyst slurry from the line 24 through a mixer before the nitrobenzene is fed into the reactor 101, and then fed into the reactor 101 together; simultaneously, the new catalyst slurry is also mixed with the circulating catalyst slurry through a pipeline 18, and then is mixed with nitrobenzene and added into the reactor 101;

(2) as nitrobenzene reacts with hydrogen in reactor 101, the temperature of reactor 101 will gradually increase, and the level of catalyst slurry in reactor 101 will also gradually increase due to the production of aniline and water during the nitrobenzene reaction;

(3) when the temperature of the control point of the reactor 101 exceeds 100 ℃, aniline wastewater is added into the reactor 101 through a pipeline 5 to control the heating rate of the reactor 101;

(4) the temperature of the circulating catalyst slurry rises along with the temperature rise of the reactor 101, when the temperature of the catalyst slurry exceeds 100 ℃, the catalyst slurry heats hot water through a catalyst cooler 202 to achieve the purpose of cooling, the heated hot water returns to a hot water system through a pipeline 34, and the catalyst slurry is cooled to 80-100 ℃;

(5) when the liquid level L201 of the catalyst circulation tank 201 reaches 30-80%, closing the automatic valve V206, and at the moment, the liquid level L201 of the catalyst circulation tank 201 will descend, opening the automatic valve V203 arranged on the outlet pipeline 27 of the catalyst filter liquid pump 204 to replenish the catalyst circulation tank 201 with the catalyst slurry, and maintaining the liquid level stable;

(6) along with the rise of the liquid level in the reactor 101, the catalyst slurry overflows into the catalyst circulation tank 201 through the pipeline 7, the flow rate of the catalyst slurry at the outlet of the catalyst filtrate pump 204 is adjusted in time, the liquid level of the catalyst circulation tank 201 is kept stable, and the temperature distribution of the reactor 101 is normal;

(7) after the feeding is finished, the gas-phase material at the top of the reactor 101 enters a subsequent condensation separation process through a pipeline 6;

4) Catalyst filtering of tar

(1) One part of the catalyst cooled by the catalyst cooler 202 enters a catalyst circulating pump 203 through a pipeline 22, and the other part of the catalyst is decompressed to 0.4-0.6MPa (g) through an automatic valve V208 through a pipeline 12 and then enters a catalyst filtering system, and the flow is controlled to be 10-20t/h through a flow meter F207;

(2) a portion of the heavies species is removed in the catalyst filtration system and the filtered catalyst slurry is returned to the catalyst feed tank 104 via line 19;

5) Catalyst feed tank 104 material recovery

The condenser 105 is arranged at the top of the catalyst feeding tank 104 and is used for condensing gas-phase materials evaporated in the catalyst feeding tank 104, the condenser 105 is cooled by cooling water, the temperature T104 of a condensation outlet is controlled to be 20-40 ℃, and non-condensable gas is discharged at a safe place through a pipeline 21;

6) Automatic control

(1) The pressure of the catalyst circulation tank 201 is kept in equilibrium with the reactor 101 through the communicating tube 8;

(2) the liquid level L201 of the catalyst circulation tank 201 is controlled by adjusting the flow of the catalyst slurry through an automatic valve V203, and the flow of the catalyst slurry is displayed through a flowmeter F203;

(3) the temperature T201 at the lower part of the catalyst cooler 202 is controlled by adjusting the flow of hot water through an automatic valve V205 arranged on the pipeline 33, and forms an adjusting loop with the automatic valve V205, and the flow meter F205 displays the flow;

(4) the total outlet flow F201 of the catalyst circulating pump 203 is regulated by an automatic valve V201 arranged on a pipeline 23, and one end of the pipeline 23 is connected with a spray head for preventing the catalyst from settling at the bottom of the catalyst circulating tank 201;

(5) the flow F202 of the catalyst circulating pump 203 from the outlet to the reactor 101 is controlled by the automatic valve V202, and forms a regulating loop with the automatic valve V202;

(6) the temperature T101 of the catalyst feed tank 104 is controlled by supplying heat through the catalyst heater 106;

(7) a pipeline 28 is arranged at the outlet of the catalyst filtrate pump 204, the refluxed catalyst slurry enters the catalyst feeding tank 104 after being heated by the catalyst heater 106, the flow is regulated by an automatic valve V204, and the tail end of the pipeline is connected with a spray head to prevent the catalyst from accumulating;

(8) the liquid level L102 of the catalyst feeding tank 104 is controlled by crude aniline added through a pipeline 20, the added crude aniline is heated by a catalyst heater 106 and mixed with a pipeline 29 to enter the catalyst feeding tank 104, the flow is displayed by a flowmeter F105 and is regulated by an automatic valve V105, and the automatic valve V105 and the liquid level L102 of the catalyst feeding tank 104 form a regulating loop;

(9) the pressure of the catalyst feed tank 104 is controlled by a line 21 provided at the top, the line 21 is discharged at a safe place, and the pressure of the catalyst feed tank 104 is the same as the pressure at the discharge point;

in case that the liquid level of the catalyst circulation tank 201 rises faster at the initial start-up, the automatic valve V207 provided on the line 35 may be opened to discharge to the catalyst feed tank 104, and the flow rate is shown by the flow meter F206.

Further, the process of replenishing the catalyst slurry of step 1 (3) to the catalyst circulation tank 201 is: catalyst slurry in the catalyst feed tank 104 enters a catalyst filtrate pump 204 through a pipeline 26, a material at the outlet of the catalyst filtrate pump 204 is divided into two parts, one part of the material enters the catalyst circulation tank 201 through a pipeline 27, and an automatic valve V203 and a flow meter F203 which are arranged on the pipeline 27 and the liquid level L201 of the catalyst circulation tank 201 form a regulating loop so as to control the liquid level of the catalyst circulation tank 201; another portion of the feed is returned to the catalyst feed tank 104 via line 28. An automatic valve V204 and flow meter F204 provided in line 28 form a regulating loop for regulating the amount of return.

Further, the reflux of the line 28 is performed in two ways, one is directly reflux to the catalyst feed tank 104 through a line 29, and the other is directly reflux to the catalyst feed tank 104 through a line 30 to the catalyst heater 106, heated by the catalyst heater 106 and then reflux to the catalyst feed tank 104.

Further, the crude aniline in step 1 (4) is supplemented by two ways, namely, directly adding the crude aniline into the catalyst feed tank 104 through a pipeline 31, and feeding the crude aniline into the catalyst heater 106 through a pipeline 32, heating the crude aniline to 50-100 ℃ through the catalyst heater 106, and then feeding the crude aniline into the catalyst feed tank 104, so as to finally realize catalyst circulation.

The second scheme for solving the technical problem of the invention is as follows: the utility model provides a liquid phase nitrobenzene hydrogenation catalyst circulation device for technology, it includes reactor 101, catalyst heater 106, catalyst feed tank 104 and condenser 105, characterized by: the reactor 101 is sequentially provided with a nitrobenzene inlet, a first quenching water inlet, a hydrogen inlet, a second quenching water inlet, a second overflow outlet, a first overflow outlet and a gas communication inlet from bottom to top, and the top of the reactor 101 is provided with a gas phase outlet; a catalyst cooler 202 is arranged in the catalyst circulation tank 201, a hot water inlet of the catalyst cooler 202 is connected with an outlet of a hot water system through a pipeline 33, a hot water outlet of the catalyst cooler 202 is connected with a water return port of the hot water system through a pipeline 34, a liquid phase outlet is arranged at the bottom of the catalyst circulation tank 201, a second backflow inlet is arranged below the catalyst cooler 202 and on the side surface of the catalyst circulation tank 201, a gas phase communication outlet is arranged at the top of the catalyst circulation tank 201, and a second overflow inlet, a second catalyst inlet and a first overflow inlet are sequentially arranged above the catalyst cooler 202 and on the side surface of the catalyst circulation tank 201 from bottom to top; the catalyst feeding tank 104 is used as a catalyst filtrate tank and is sequentially provided with a catalyst outlet, a first reflux inlet, a liquid phase inlet and a first inlet from bottom to top, the top of the catalyst feeding tank 104 is provided with the condenser 105 and is communicated with the condenser, and the bottom of the catalyst feeding tank is provided with a liquid outlet; a nitrobenzene inlet of the reactor 101 is connected with a nitrobenzene system through a pipeline 2, a first quench water inlet and a second quench water inlet of the reactor 101 are simultaneously connected with the quench water system through a pipeline 5, a hydrogen inlet of the reactor 101 is communicated with the hydrogen system through a pipeline 1, a first overflow outlet of the reactor 101 is connected with a first overflow inlet of the catalyst circulation tank 201 through a pipeline 7, a second overflow outlet is connected with a second overflow inlet of the catalyst circulation tank 201 through a pipeline 25, a gas phase communication inlet of the reactor 101 is communicated with a gas phase communication outlet of the catalyst circulation tank 201 through a communicating pipe 8, and a gas phase outlet of the reactor 101 is communicated with a subsequent condensation separation system through a pipeline 6; a liquid phase outlet at the bottom of the catalyst circulation tank 201 is connected with an inlet of a catalyst circulation pump 203 through a pipeline 22, an outlet of the catalyst circulation pump 203 is communicated with a pipeline 2 through a pipeline 24 and is simultaneously connected with a second backflow inlet of the catalyst circulation tank 201 through a pipeline 23; the catalyst outlet of the catalyst feed tank 104 is connected with the inlet of the catalyst filtrate pump 204 through a pipeline 26, the outlet of the catalyst filtrate pump 204 is connected with the second catalyst inlet of the catalyst circulation tank 201 through a pipeline 27 and is simultaneously provided with a pipeline 28, the outlet of the pipeline 28 is simultaneously provided with a pipeline 29 and a pipeline 30, the pipeline 29 is directly connected with the first reflux inlet of the catalyst feed tank 104, the pipeline 30 is connected with the catalyst inlet of the catalyst heater 106, the catalyst outlet of the catalyst heater 106 is connected with the first reflux inlet of the catalyst feed tank 104, and the steam channel of the catalyst heater 106 is connected with a steam system; the gas phase outlet at the top of the condenser 105 is vented via line 21 and the cooling water line of the condenser 105 is connected to a cooling water system.

Further, the liquid phase outlet at the bottom of the catalyst circulation tank 201 is connected with the inlet of the catalyst circulation pump 203 through a pipeline 22, and is also connected with the inlet of the catalyst filtering device through a pipeline 12, and the outlet of the catalyst filtering device is communicated with the first inlet of the catalyst feeding tank 104 through a pipeline 19 for returning the filtered catalyst.

Further, the pipeline (12) is connected with a liquid phase outlet at the bottom of the catalyst circulation tank (201) and is also connected with a liquid phase inlet of the catalyst feeding tank (104) through a pipeline (35).

Further, the liquid-phase nitrobenzene hydrogenation catalyst circulation device is further provided with a crude aniline pipeline, a pipeline 20 is arranged at the outlet of the crude aniline system, a pipeline 31 and a pipeline 32 are simultaneously arranged at the outlet of the pipeline 20, the pipeline 31 is connected with the first reflux inlet of the catalyst feed tank 104, and the pipeline 32 is connected with the catalyst inlet of the catalyst heater 106.

Further, the fresh catalyst system of the liquid phase nitrobenzene hydrogenation catalyst recycle is in communication with line 24 via line 18 and then in communication with line 2.

Further, the liquid-phase nitrobenzene hydrogenation catalyst circulating device is provided with a control system, and the structure is as follows: an automatic valve V206 is arranged on the pipeline 25 and is used for communicating with the catalyst circulating pipeline; an automatic valve V201 is arranged on the pipeline 23, and a spray head for preventing the catalyst from settling is arranged at the tail end of the pipeline 23 so as to control the outlet total flow F201 of the catalyst circulating pump 203; a flow meter F202 and an automatic valve V202 are sequentially arranged behind the connection point of the pipeline 23 and the pipeline 24 and used for regulating the flow of the pipeline 24; a flow meter F203 and an automatic valve V203 are sequentially arranged on the pipeline 27 behind the connection point of the pipeline 27 and the pipeline 28, and the automatic valve V203 and the liquid level L201 of the catalyst circulation tank 201 form a regulating loop for controlling the liquid level of the catalyst circulation tank 201; a thermometer T202, a flowmeter F205 and an automatic valve V205 are sequentially arranged on the pipeline 33 and between the outlet of the hot water system and the hot water inlet of the catalyst cooler 202, and the thermometer T202, the flowmeter F205 and the automatic valve V205 form a regulating loop for regulating the flow rate of the hot water and controlling the lower temperature T201 of the catalyst cooler 202; an automatic valve V208 and a flowmeter F207 are sequentially arranged on the pipeline 12 and in front of the inlet of the catalyst filtering device and are used for controlling the flow entering the catalyst filtering device; a flow meter F206 and an automatic valve V207 are sequentially arranged on the pipeline 35 and before the liquid phase inlet of the catalyst feed tank 104 and are used for regulating and controlling the flow rate of the liquid entering the catalyst feed tank 104; a flow meter F204 and an automatic valve V204 are sequentially arranged on the pipeline 28 from the inlet to the outlet and used for adjusting and controlling the flow entering the catalyst heater 106, a flow meter F105 and an automatic valve 105 are sequentially arranged on the pipeline 20 from the inlet to the outlet, and the flow meter F105, the automatic valve 105 and the liquid level L102 of the catalyst feed tank 104 form an adjusting loop and used for controlling the liquid level of the catalyst feed tank 104; a thermometer T102 was disposed at the outlet of the catalyst heater 106, a thermometer T101 was disposed in the catalyst feed tank 104, and a thermometer T104 was disposed in the line 21.

The invention has the beneficial effects that: the process flow and the device thereof provided by the invention can realize the catalyst circulation operation at the initial start-up stage, and provide a large buffer space, thereby not only reducing the operation variables at the initial start-up stage, but also being beneficial to the stable operation of the reactor, and further improving the safety of the device. The catalyst heating process at the initial start-up stage is provided, and the stable temperature rise of the reactor is facilitated. And a heat recovery process is provided, and in the normal use process, the catalyst is cooled and cooled while heat is recovered.

Drawings

FIG. 1 is a schematic diagram of a liquid phase nitrobenzene hydrogenation catalyst circulation unit of the prior art;

FIG. 2 is an enlarged view of a portion I of FIG. 1;

FIG. 3 is an enlarged partial view of section II of FIG. 1;

FIG. 4 is a structural diagram of a liquid-phase nitrobenzene hydrogenation catalyst circulation unit according to the present invention;

FIG. 5 is an enlarged partial view of FIG. 4;

FIG. 6 is an enlarged partial view of IV in FIG. 4.

In the figure: 1-7 pipelines, 8 communicating pipes, 9-35 pipelines, 101 reactor, 102 degassing tank, 103 air cooler, 104 catalyst feed tank, 105 condenser, 106 catalyst heater, 107 catalyst filter pump, 108 catalyst feed pump, 201 catalyst circulation tank, 202 catalyst cooler, 203 catalyst circulation pump, 204 catalyst filter pump, V101-V105 automatic valve, V201-V208 automatic valve, F105 flowmeter, F201 outlet total flow, F202-F207 flowmeter, L102 liquid level, L201 liquid level, T101 temperature, T104 temperature, T201 temperature.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

Referring to fig. 4 to 6, in example 1, the liquid-phase nitrobenzene hydrogenation catalyst circulation process of this embodiment includes catalyst circulation at the initial startup, catalyst slurry temperature rise, nitrobenzene feeding, tar filtering of the catalyst, material recovery of the catalyst feed tank 104, and automatic control, and includes the following specific steps:

1) Catalyst cycling at initial start-up

(3) the main control parameters of the process are that the liquid level L201 of the catalyst circulating tank 201 is controlled to be 10-30%, and the liquid level L102 of the catalyst feeding tank 104 is controlled to be 20-80%;

2) Catalyst slurry temperature rise

(1) Adding hydrogen to the reactor through line 1 and controlling the top pressure of reactor 101 to be 1.6-1.8MPa (g); the flow of the inflow pipeline 24 is controlled to be 10 to 20t/h through a flow meter F202 and an automatic valve V202 arranged on the outlet pipeline 24 of the catalyst circulating pump 203;

(3) the regulation process for feeding hot water into the catalyst cooler 202 is: an automatic valve V205 and a flow meter F205 arranged on the hot water pipeline 33 and the temperature T201 at the lower part of the catalyst cooler 202 form a regulating loop, the flow meter F205 indicates the added hot water amount, the hot water temperature is 80-110 ℃, and the flow rate is 5-20T/h;

fourthly, gradually raising the temperature of the circulating catalyst slurry to 50-80 ℃ through circulation of a catalyst circulating pump 203;

3) Nitrobenzene charging

(5) when the liquid level L201 of the catalyst circulation tank 201 reaches 30-80%, closing the automatic valve V206, lowering the liquid level L201 of the catalyst circulation tank 201, opening the automatic valve V203 arranged on the outlet pipeline 27 of the catalyst filtrate pump 204 to replenish the catalyst circulation tank 201 with the catalyst slurry, and maintaining the liquid level stable;

4) Catalyst filtering of tar

(1) One part of the catalyst cooled by the catalyst cooler 202 enters a catalyst circulating pump 203 through a pipeline 22, the other part of the catalyst enters a catalyst filtering system after being decompressed to 0.4-0.6MPa (g) through an automatic valve V208 through a pipeline 12, and the flow is controlled to be 10-20t/h through a flow meter F207;

5) Catalyst feed tank 104 material recovery

The condenser 105 is arranged at the top of the catalyst feeding tank 104 and is used for condensing gas-phase materials evaporated in the catalyst feeding tank 104, the condenser 105 is cooled by cooling water, the temperature T104 of a condensation outlet is controlled to be 20-40 ℃, and non-condensable gas is discharged at a safe position through a pipeline 21;

6) Automatic control

(5) the flow F202 of the catalyst circulating pump 203 entering the reactor 101 is controlled by an automatic valve V202 and forms a regulating loop with the automatic valve V202;

(7) the outlet of the catalyst filtrate pump 204 is provided with a pipeline 28, the returned catalyst slurry enters the catalyst feeding tank 104 after being heated by the catalyst heater 106, the flow rate is regulated by an automatic valve V204, and the tail end of the pipeline is connected with a spray head to prevent the catalyst from accumulating;

The device for the liquid-phase nitrobenzene hydrogenation catalyst circulation process comprises a reactor 101, a catalyst heater 106, a catalyst feeding tank 104, a condenser 105, a catalyst circulation tank 201, a catalyst cooler 202, a catalyst circulation pump 203 and a catalyst filtrate pump 204, wherein the reactor 101 is sequentially provided with a nitrobenzene inlet, a first chilled water inlet, a hydrogen inlet, a second chilled water inlet, a second overflow outlet, a first overflow outlet and a gas communication inlet from bottom to top, and the top of the reactor 101 is provided with a gas phase outlet; a catalyst cooler 202 is arranged in the catalyst circulating tank 201, a hot water inlet of the catalyst cooler 202 is connected with a hot water system outlet through a pipeline 33, a hot water outlet of the catalyst cooler 202 is connected with a water return port of the hot water system through a pipeline 34, a liquid phase outlet is arranged at the bottom of the catalyst circulating tank 201, a second backflow inlet is arranged below the catalyst cooler 202 and on the side surface of the catalyst circulating tank 201, a gas phase communication outlet is arranged at the top of the catalyst circulating tank 201, and a second overflow inlet, a second catalyst inlet and a first overflow inlet are sequentially arranged above the catalyst cooler 202 and on the side surface of the catalyst circulating tank 201 from bottom to top; the catalyst feeding tank 104 is used as a catalyst filtrate tank and is sequentially provided with a catalyst outlet, a first reflux inlet, a liquid phase inlet and a first inlet from bottom to top, the top of the catalyst feeding tank 104 is provided with the condenser 105 and is communicated with the condenser, and the bottom of the catalyst feeding tank is provided with a liquid outlet; a nitrobenzene inlet of the reactor 101 is connected with a nitrobenzene system through a pipeline 2, a first quench water inlet and a second quench water inlet of the reactor 101 are simultaneously connected with the quench water system through a pipeline 5, a hydrogen inlet of the reactor 101 is communicated with the hydrogen system through a pipeline 1, a first overflow outlet of the reactor 101 is connected with a first overflow inlet of the catalyst circulation tank 201 through a pipeline 7, a second overflow outlet is connected with a second overflow inlet of the catalyst circulation tank 201 through a pipeline 25, a gas phase communication inlet of the reactor 101 is communicated with a gas phase communication outlet of the catalyst circulation tank 201 through a communicating pipe 8, and a gas phase outlet of the reactor 101 is communicated with a subsequent condensation separation system through a pipeline 6; a liquid phase outlet at the bottom of the catalyst circulation tank 201 is connected with an inlet of a catalyst circulation pump 203 through a pipeline 22, an outlet of the catalyst circulation pump 203 is communicated with a pipeline 2 through a pipeline 24 and is simultaneously connected with a second backflow inlet of the catalyst circulation tank 201 through a pipeline 23; the catalyst outlet of the catalyst feed tank 104 is connected with the inlet of the catalyst filtrate pump 204 through a pipeline 26, the outlet of the catalyst filtrate pump 204 is connected with the second catalyst inlet of the catalyst circulation tank 201 through a pipeline 27 and is simultaneously provided with a pipeline 28, the outlet of the pipeline 28 is simultaneously provided with a pipeline 29 and a pipeline 30, the pipeline 29 is directly connected with the first reflux inlet of the catalyst feed tank 104, the pipeline 30 is connected with the catalyst inlet of the catalyst heater 106, the catalyst outlet of the catalyst heater 106 is connected with the first reflux inlet of the catalyst feed tank 104, and the steam channel of the catalyst heater 106 is connected with a steam system; the gas phase outlet at the top of the condenser 105 is vented via line 21 and the cooling water line of the condenser 105 is connected to a cooling water system.

The liquid phase outlet at the bottom of the catalyst circulation tank 201 is connected with the inlet of the catalyst circulation pump 203 through a pipeline 22, and is also connected with the inlet of the catalyst filtering device through a pipeline 12, and the outlet of the catalyst filtering device is communicated with the first inlet of the catalyst feeding tank 104 through a pipeline 19 and is used for returning the filtered catalyst.

The pipeline (12) is connected with a liquid phase outlet at the bottom of the catalyst circulating tank (201) and is also connected with a liquid phase inlet of the catalyst feeding tank (104) through a pipeline (35).

The liquid-phase nitrobenzene hydrogenation catalyst circulation device is also provided with a crude aniline pipeline, a pipeline 20 is arranged at the outlet of the crude aniline system, a pipeline 31 and a pipeline 32 are simultaneously arranged at the outlet of the pipeline 20, the pipeline 31 is connected with a first reflux inlet of the catalyst feed tank 104, and the pipeline 32 is connected with a catalyst inlet of the catalyst heater 106.

The fresh catalyst system of the liquid phase nitrobenzene hydrogenation catalyst recycle is in communication with line 24 via line 18 and then in communication with line 2.

The liquid-phase nitrobenzene hydrogenation catalyst circulating device is provided with a control system, and the structure is as follows: an automatic valve V206 is arranged on the pipeline 25 and is used for communicating with the catalyst circulating pipeline; an automatic valve V201 is arranged on the pipeline 23, and a spray head for preventing the catalyst from settling is arranged at the tail end of the pipeline 23 so as to control the outlet total flow F201 of the catalyst circulating pump 203; a flow meter F202 and an automatic valve V202 are arranged behind the connection point of the pipeline 23 and the pipeline 24 in sequence and used for regulating the flow of the pipeline 24; a flow meter F203 and an automatic valve V203 are sequentially arranged on the pipeline 27 behind the connection point of the pipeline 27 and the pipeline 28, and the automatic valve V203 and the liquid level L201 of the catalyst circulation tank 201 form a regulating loop for controlling the liquid level of the catalyst circulation tank 201; a thermometer T202, a flowmeter F205 and an automatic valve V205 are sequentially arranged on the pipeline 33, between the outlet of the hot water system and the hot water inlet of the catalyst cooler 202, and the thermometer T202, the flowmeter F205 and the automatic valve V205 form a regulating loop for regulating the flow rate of hot water and controlling the lower temperature T201 of the catalyst cooler 202; an automatic valve V208 and a flow meter F207 are sequentially arranged on the pipeline 12 and in front of the inlet of the catalyst filtering device and are used for controlling the flow entering the catalyst filtering device; a flow meter F206 and an automatic valve V207 are sequentially arranged on the pipeline 35 and before the liquid phase inlet of the catalyst feed tank 104 and are used for adjusting and controlling the flow rate of the liquid entering the catalyst feed tank 104; a flow meter F204 and an automatic valve V204 are sequentially arranged on the pipeline 28 from the inlet to the outlet and used for adjusting and controlling the flow entering the catalyst heater 106, a flow meter F105 and an automatic valve 105 are sequentially arranged on the pipeline 20 from the inlet to the outlet, and the flow meter F105, the automatic valve 105 and the liquid level L102 of the catalyst feed tank 104 form an adjusting loop and used for controlling the liquid level of the catalyst feed tank 104; a thermometer T102 was disposed at the outlet of the catalyst heater 106, a thermometer T101 was disposed at the catalyst feed tank 104, and a thermometer T104 was disposed on the line 21.

Referring to fig. 4 to fig. 6, in example 2, the liquid phase nitrobenzene hydrogenation catalyst cycle process of this example is as follows: the method comprises the steps of catalyst circulation at the initial startup, catalyst slurry temperature rise, nitrobenzene feeding, tar filtering of the catalyst, material recovery of a catalyst feed tank 104 and automatic control, and specifically comprises the following steps:

1) Catalyst cycling at initial start-up

the process of replenishing the catalyst slurry to the catalyst circulation tank 201 is: catalyst slurry in the catalyst feeding tank 104 enters a catalyst filtrate pump 204 through a pipeline 26, the material at the outlet of the catalyst filtrate pump 204 is divided into two parts, one part of the material enters a catalyst circulation tank 201 through a pipeline 27, and an automatic valve V203 and a flowmeter F203 which are arranged on the pipeline 27 and the liquid level L201 of the catalyst circulation tank 201 form a regulating loop so as to control the liquid level of the catalyst circulation tank 201; the other part of the material flows back to the catalyst feed tank 104 through a pipeline 28, and an automatic valve V204 and a flowmeter F204 arranged on the pipeline 28 form a regulating loop for regulating the return flow;

the reflux of line 28 is carried out in two ways, one is directly reflux to the catalyst feed tank 104 through line 29, and the other is directly reflux to the catalyst feed tank 104 through line 30, and the other is fed to the catalyst heater 106 and heated by the catalyst heater 106;

(4) the main control parameters of the process are that the liquid level L201 of the catalyst circulation tank 201 is controlled to be 10-30%, and the liquid level L102 of the catalyst feeding tank 104 is controlled to be 20-80%;

2) Catalyst slurry temperature rise

3) Nitrobenzene feeding material

(2) as nitrobenzene reacts with hydrogen in the reactor 101, the temperature of the reactor 101 will gradually increase, and the level of catalyst slurry in the reactor 101 will gradually increase due to the production of aniline and water during the nitrobenzene reaction;

4) Catalyst filtering of tar

5) Catalyst feed tank 104 material recovery

6) Automatic control

(4) the total flow F201 of the outlet of the catalyst circulating pump 203 is regulated by an automatic valve V201 arranged on a pipeline 23, and one end of the pipeline 23 is connected with a spray head for preventing the catalyst from settling at the bottom of the catalyst circulating tank 201;

The apparatus used in this example was the same as that used in example 1.

Example 3, the process of the liquid phase nitrobenzene hydrogenation catalyst cycle of this example was: the method comprises the steps of catalyst circulation at the initial startup, catalyst slurry temperature rise, nitrobenzene feeding, catalyst tar filtering, material recovery of a catalyst feeding tank 104 and automatic control, and specifically comprises the following steps:

1) Catalyst cycling at initial start-up

the process of replenishing the catalyst slurry to the catalyst circulation tank 201 is: catalyst slurry in the catalyst feed tank 104 enters a catalyst filtrate pump 204 through a pipeline 26, a material at the outlet of the catalyst filtrate pump 204 is divided into two parts, one part of the material enters the catalyst circulation tank 201 through a pipeline 27, and an automatic valve V203 and a flow meter F203 which are arranged on the pipeline 27 and the liquid level L201 of the catalyst circulation tank 201 form a regulating loop so as to control the liquid level of the catalyst circulation tank 201; the other part of the materials flow back to the catalyst feeding tank 104 through a pipeline 28, and an automatic valve V204 and a flow meter F204 arranged on the pipeline 28 form a regulating loop for regulating the flow back;

the reflux of the line 28 is performed in two ways, one way is to directly reflux the catalyst feed tank 104 through a line 29, and the other way is to reflux the catalyst feed tank 104 after entering the catalyst heater 106 through a line 30 and being heated by the catalyst heater 106;

the crude aniline is supplemented by two ways, namely directly adding the crude aniline into a catalyst feeding tank 104 through a pipeline 31, and feeding the crude aniline into a catalyst heater 106 through a pipeline 32, heating the crude aniline to 50-100 ℃ through the catalyst heater 106, and then feeding the crude aniline into the catalyst feeding tank 104 to finally realize catalyst circulation;

(5) the main control parameters of the process are that the liquid level L201 of the catalyst circulation tank 201 is controlled to be 10-30%, and the liquid level L102 of the catalyst feeding tank 104 is controlled to be 20-80%;

2) Catalyst slurry temperature rise

(1) Hydrogen is added to the reactor through line 1 and the pressure at the top of reactor 101 is controlled to be 1.6-1.8MPa (g); the flow of the inflow pipeline 24 is controlled to be 10 to 20t/h through a flow meter F202 and an automatic valve V202 arranged on the outlet pipeline 24 of the catalyst circulating pump 203;

3) Nitrobenzene charging

(1) Nitrobenzene is fed into the reactor 101 through the line 2 provided, and mixed with the catalyst slurry from the line 24 through a mixer before the nitrobenzene is fed into the reactor 101, and then fed into the reactor 101 together; simultaneously, new catalyst slurry is also mixed with the circulating catalyst slurry through a pipeline 18 and then is mixed with nitrobenzene and added into the reactor 101;

4) Catalyst filtering of tar

5) Catalyst feed tank 104 material recovery

6) Automatic control

in case the liquid level in catalyst circulation tank 201 rises faster in the initial period of start-up, automatic valve V207 provided on line 35 may be opened to discharge to catalyst feed tank 104, and the flow rate is shown by flow meter F206.

The apparatus used in this example was the same as that used in example 1.

The present invention is not limited to the present embodiment, and it is possible for those skilled in the art to easily reproduce and modify the present invention without inventive efforts within the scope of the present invention claimed.

Claims

1. A liquid-phase nitrobenzene hydrogenation catalyst circulation process is characterized in that: the method comprises the steps of catalyst circulation at the initial startup, catalyst slurry temperature rise, nitrobenzene feeding, tar filtering of the catalyst, material recovery of a catalyst feeding tank (104) and automatic control, and specifically comprises the following steps:

1) Catalyst cycling at initial start-up

(1) Starting a catalyst circulating pump (203), wherein catalyst slurry in a catalyst circulating tank (201) firstly flows out of the catalyst circulating tank (201) through a catalyst cooler (202), then enters the catalyst circulating pump (203) through an eleventh pipeline (22), the material at the outlet of the catalyst circulating pump (203) is divided into two parts, one part of the material returns to the catalyst circulating tank (201) through a twelfth pipeline (23), and a second automatic valve (V201) arranged on the twelfth pipeline (23) controls the total flow (F201) of the outlet of the catalyst circulating pump (203) to be 10-30t/h; the other part of the materials are pumped into the reactor (101) through a thirteenth pipeline (24), a third automatic valve (V202) arranged on the thirteenth pipeline (24) and a first flow meter (F202) form a regulating loop, and the flow of the thirteenth pipeline (24) is controlled to be 10-20t/h;

(2) opening a seventh automatic valve (V206) arranged on a fourteenth pipeline (25) in the middle of the reactor (101) to enable the catalyst slurry in the reactor (101) to overflow into a catalyst circulation tank (201) to realize catalyst circulation;

(3) if the catalyst slurry in the catalyst circulation tank (201) is not enough to realize circulation, the original catalyst feeding tank (104) is changed into a catalyst filtrate tank, and the catalyst slurry in the catalyst filtrate tank is supplemented to the catalyst circulation tank (201) by a catalyst filtrate pump (204) to realize catalyst circulation;

(4) replenishing the catalyst feed tank (104) with crude aniline through a ninth line (20) provided on the catalyst feed tank (104) if the catalyst slurry in the catalyst feed tank (104) is still insufficient to achieve catalyst circulation;

(5) the main control parameters of the process are that the liquid level (L201) of the catalyst circulation tank (201) is controlled to be 10-30%, and the liquid level (L102) of the catalyst feeding tank (104) is controlled to be 20-80%;

2) Catalyst slurry temperature rise

(1) Adding hydrogen to the reactor through a first line (1) and controlling the top pressure of the reactor (101) to be 1.6-1.8MPa (g); the flow rate of the liquid flowing into the thirteenth pipeline (24) is controlled to be 10-20t/h by a first flow meter (F202) and a third automatic valve (V202) which are arranged on the thirteenth pipeline (24) at the outlet of the catalyst circulating pump (203);

(2) hot water is introduced into a catalyst cooler (202) arranged in the catalyst circulating tank (201) through a hot water pipeline (33), the temperature of catalyst slurry at the lower part of the catalyst cooler (202) is heated to 50-80 ℃, and the hot water after heat exchange and cooling of the catalyst cooler (202) returns to a hot water system through a twenty-second pipeline (34);

(3) the regulation process of introducing hot water into the catalyst cooler (202) is as follows: a sixth automatic valve (V205) and a fourth flowmeter (F205) arranged on the hot water pipeline (33) and the temperature (T201) at the lower part of the catalyst cooler (202) form a regulating loop, the fourth flowmeter (F205) indicates the added hot water, the temperature of the hot water is 80-110 ℃, and the flow is 5-20T/h;

(4) gradually raising the temperature of the circulating catalyst slurry to 50-80 ℃ through the circulation of a catalyst circulating pump (203);

3) Nitrobenzene charging

(1) Nitrobenzene is fed into the reactor (101) through the second line (2) provided, and mixed with the catalyst slurry from the thirteenth line (24) through a mixer before the nitrobenzene is fed into the reactor (101), and then fed into the reactor (101) together; simultaneously, new catalyst slurry is mixed with the circulating catalyst slurry through a seventh pipeline (18) and then is mixed with nitrobenzene and added into the reactor (101);

(2) as nitrobenzene reacts with hydrogen in the reactor (101), the temperature of the reactor (101) gradually increases, and the liquid level of the catalyst slurry in the reactor (101) gradually increases due to the production of aniline and water during the nitrobenzene reaction;

(3) when the temperature of the control point of the reactor (101) exceeds 100 ℃, aniline wastewater is added into the reactor (101) through a third pipeline (5) so as to control the temperature rising rate of the reactor (101);

(4) the temperature of the circulating catalyst slurry rises along with the temperature rise of the reactor (101), when the temperature of the catalyst slurry exceeds 100 ℃, the catalyst slurry heats hot water through a catalyst cooler (202) so as to realize the cooling purpose, the heated hot water returns to a hot water system through a twenty-two pipeline (34), and the catalyst slurry is cooled to 80-100 ℃;

(5) when the liquid level (L201) of the catalyst circulating tank (201) reaches 30-80%, closing the seventh automatic valve (V206), lowering the liquid level (L201) of the catalyst circulating tank (201), opening a fourth automatic valve (V203) arranged on a sixteenth pipeline (27) at the outlet of the catalyst filtrate pump (204) to replenish the catalyst circulating tank (201) with catalyst slurry, and maintaining the liquid level stable;

(6) along with the rise of the liquid level in the reactor (101), catalyst slurry overflows into the catalyst circulation tank (201) through the fifth pipeline (7), the flow rate of the catalyst slurry at the outlet of the catalyst filter pump (204) is adjusted in time, the liquid level of the catalyst circulation tank (201) is kept stable, and the temperature distribution of the reactor (101) is normal;

(7) after the feeding is finished, the gas-phase material at the top of the reactor (101) enters a subsequent condensation separation process through a fourth pipeline (6);

4) Catalyst filtering of tar

(1) One part of the catalyst cooled by the catalyst cooler (202) enters a catalyst circulating pump (203) through an eleventh pipeline (22), the other part of the catalyst enters a catalyst filtering system after being decompressed to 0.4-0.6MPa (g) through a sixth pipeline (12) through a ninth automatic valve (V208), and the flow is controlled to be 10-20t/h through a sixth flowmeter (F207);

(2) removing a portion of the heavies species in the catalyst filtration system and returning the filtered catalyst slurry to the catalyst feed tank (104) via an eighth line (19);

5) Catalyst feed tank (104) material recovery

The condenser (105) is arranged at the top of the catalyst feeding tank (104) and is used for condensing gas-phase materials evaporated in the catalyst feeding tank (104), the condenser (105) is cooled by cooling water, the temperature (T104) of a condensation outlet is controlled to be 20-40 ℃, and non-condensable gas is discharged at a safe position through a tenth pipeline (21);

6) Automatic control

(1) The pressure of the catalyst circulating tank (201) is kept in balance with the reactor (101) through a communicating pipe (8);

(2) the liquid level (L201) of the catalyst circulating tank (201) is controlled by adjusting the flow rate of the catalyst slurry through a fourth automatic valve (V203), and the flow rate of the catalyst slurry is displayed through a second flow meter (F203);

(3) the temperature (T201) at the lower part of the catalyst cooler (202) is controlled by adjusting the flow of hot water through a sixth automatic valve (V205) arranged on a hot water pipeline (33), and forms an adjusting loop with the sixth automatic valve (V205), and a fourth flowmeter (F205) displays the flow;

(4) the total outlet flow (F201) of the catalyst circulating pump (203) is regulated by a second automatic valve (V201) arranged on a twelfth pipeline (23), and one end of the twelfth pipeline (23) is connected with a spray head for preventing the catalyst from settling at the bottom of the catalyst circulating tank (201);

(5) the flow entering the reactor (101) from the outlet of the catalyst circulating pump (203) is controlled by a third automatic valve (V202) and forms a regulating loop with the third automatic valve (V202);

(6) the temperature (T101) of the catalyst feed tank (104) is controlled by supplying heat through a catalyst heater (106);

(7) a seventeenth pipeline (28) is arranged at the outlet of the catalyst filtrate pump (204), the returned catalyst slurry enters the catalyst feeding tank (104) after being heated by the catalyst heater (106), the flow rate is regulated by a fifth automatic valve (V204), and the tail end of the pipeline is connected with a spray head to prevent the catalyst from accumulating;

(8) the liquid level (L102) of the catalyst feeding tank (104) is controlled by crude aniline added through a ninth pipeline (20), the added crude aniline is heated through a catalyst heater (106) and is mixed with an eighteenth pipeline (29) and then enters the catalyst feeding tank (104), the flow is displayed through a seventh flow meter (F105) and is adjusted through a first automatic valve (V105), and the first automatic valve (V105) and the liquid level (L102) of the catalyst feeding tank (104) form an adjusting loop;

(9) the pressure of the catalyst feed tank (104) is controlled by a tenth line (21) provided at the top, the tenth line (21) is discharged at a safe place, and the pressure of the catalyst feed tank (104) is the same as the pressure at the discharge point;

in case that the liquid level of the catalyst circulation tank (201) rises rapidly at the start-up, an eighth automatic valve (V207) provided on a twenty-third line (35) is opened to discharge to the catalyst feed tank (104), and the flow rate is indicated by a fifth flow meter (F206).

2. The liquid phase nitrobenzene hydrogenation catalyst recycle process of claim 1, wherein: the process of replenishing the catalyst slurry (3) of the step 1) into the catalyst circulating tank (201) is as follows: catalyst slurry in the catalyst feeding tank (104) enters a catalyst filtrate pump (204) through a fifteenth pipeline (26), the material at the outlet of the catalyst filtrate pump (204) is divided into two parts, one part of the material enters the catalyst circulating tank (201) through a sixteenth pipeline (27), and a fourth automatic valve (V203) and a second flow meter (F203) which are arranged on the sixteenth pipeline (27) and the liquid level (L201) of the catalyst circulating tank (201) form a regulating loop so as to control the liquid level of the catalyst circulating tank (201); the other part of the materials flow back to the catalyst feeding tank (104) through a seventeenth pipeline (28), and a fifth automatic valve (V204) arranged on the seventeenth pipeline (28) and a third flow meter (F204) form a regulating loop for regulating the back flow.

3. The liquid phase nitrobenzene hydrogenation catalyst recycle process of claim 2, wherein: the seventeenth line (28) is refluxed directly to the catalyst feed tank (104) through an eighteenth line (29), and is refluxed to the catalyst feed tank (104) after being heated by the catalyst heater (106) through a nineteenth line (30).

4. The liquid phase nitrobenzene hydrogenation catalyst recycle process of claim 1, wherein: the crude aniline supplement in the step 1) (4) has two ways, namely, the crude aniline is directly added into the catalyst feeding tank (104) through a twentieth pipeline (31), and the crude aniline enters the catalyst heater (106) through a twenty-first pipeline (32), is heated to 50-100 ℃ by the catalyst heater (106) and then enters the catalyst feeding tank (104), and finally, the catalyst circulation is realized.

5. The utility model provides a device for liquid phase nitrobenzene hydrogenation catalyst circulation technology, it includes reactor (101), catalyst heater (106), catalyst feed jar (104) and condenser (105), characterized by: the reactor is characterized by also comprising a catalyst circulating tank (201), a catalyst cooler (202), a catalyst circulating pump (203) and a catalyst filtrate pump (204), wherein the reactor (101) is sequentially provided with a nitrobenzene inlet, a first chilled water inlet, a hydrogen inlet, a second chilled water inlet, a second overflow outlet, a first overflow outlet and an air-communicated inlet from bottom to top, and the top of the reactor (101) is provided with a gas-phase outlet; a catalyst cooler (202) is arranged in the catalyst circulating tank (201), a hot water inlet of the catalyst cooler (202) is connected with an outlet of a hot water system through a hot water pipeline (33), a hot water outlet of the catalyst cooler (202) is connected with a water return port of the hot water system through a twenty-two pipeline (34), a liquid phase outlet is arranged at the bottom of the catalyst circulating tank (201), a second backflow inlet is arranged below the catalyst cooler (202) and on the side surface of the catalyst circulating tank (201), a gas phase communication outlet is arranged at the top of the catalyst circulating tank (201), and a second overflow inlet, a second catalyst inlet and a first overflow inlet are sequentially arranged above the catalyst cooler (202) and on the side surface of the catalyst circulating tank (201) from bottom to top; the catalyst feeding tank (104) is used as a catalyst filtrate tank and is sequentially provided with a catalyst outlet, a first reflux inlet, a liquid phase inlet and a first inlet from bottom to top, the top of the catalyst feeding tank (104) is provided with the condenser (105) and communicated with the condenser, and the bottom of the catalyst feeding tank (104) is provided with a liquid outlet; a nitrobenzene inlet of the reactor (101) is connected with a nitrobenzene system through a second pipeline (2), a first quenching water inlet and a second quenching water inlet of the reactor (101) are simultaneously connected with the quenching water system through a third pipeline (5), a hydrogen inlet of the reactor (101) is communicated with the hydrogen system through a first pipeline (1), a first overflow outlet of the reactor (101) is connected with a first overflow inlet of the catalyst circulation tank (201) through a fifth pipeline (7), a second overflow outlet is connected with a second overflow inlet of the catalyst circulation tank (201) through a fourteenth pipeline (25), a gas phase communication inlet of the reactor (101) is communicated with a gas phase communication outlet of the catalyst circulation tank (201) through a communicating pipe (8), and a gas phase outlet of the reactor (101) is communicated with a subsequent condensation separation system through a fourth pipeline (6); a liquid phase outlet at the bottom of the catalyst circulating tank (201) is connected with an inlet of a catalyst circulating pump (203) through an eleventh pipeline (22), an outlet of the catalyst circulating pump (203) is communicated with the second pipeline (2) through a thirteenth pipeline (24) and is simultaneously connected with a second backflow inlet of the catalyst circulating tank (201) through a twelfth pipeline (23); a catalyst outlet of the catalyst feeding tank (104) is connected with an inlet of a catalyst filtrate pump (204) through a fifteenth pipeline (26), an outlet of the catalyst filtrate pump (204) is connected with a second catalyst inlet of the catalyst circulation tank (201) through a sixteenth pipeline (27) and is simultaneously provided with a seventeenth pipeline (28), an outlet of the seventeenth pipeline (28) is simultaneously provided with an eighteenth pipeline (29) and a nineteenth pipeline (30), the eighteenth pipeline (29) is directly connected with a first reflux inlet of the catalyst feeding tank (104), the nineteenth pipeline (30) is connected with a catalyst inlet of the catalyst heater (106), a catalyst outlet of the catalyst heater (106) is connected with the first reflux inlet of the catalyst feeding tank (104), and a steam channel of the catalyst heater (106) is connected with a steam system; the gas phase outlet at the top of the condenser (105) is emptied through a tenth pipeline (21), and the cooling water pipeline of the condenser (105) is connected with a cooling water system.

6. The apparatus for liquid phase nitrobenzene hydrogenation catalyst recycle process according to claim 5, wherein: the liquid phase outlet at the bottom of the catalyst circulating tank (201) is connected with the inlet of the catalyst circulating pump (203) through an eleventh pipeline (22), and is also connected with the inlet of the catalyst filtering device through a sixth pipeline (12), and the outlet of the catalyst filtering device is communicated with the first inlet of the catalyst feeding tank (104) through an eighth pipeline (19) and is used for returning the filtered catalyst.

7. The apparatus for liquid phase nitrobenzene hydrogenation catalyst recycle process according to claim 6, wherein: the sixth pipeline (12) is connected with a liquid phase outlet at the bottom of the catalyst circulating tank (201) and is also connected with a liquid phase inlet of the catalyst feeding tank (104) through a twenty-third pipeline (35).

8. The apparatus for liquid phase nitrobenzene hydrogenation catalyst recycle process according to claim 5, wherein: the device for the liquid-phase nitrobenzene hydrogenation catalyst circulation process is also provided with a crude aniline pipeline, a ninth pipeline (20) is arranged at an outlet of a crude aniline system, a twentieth pipeline (31) and a twenty-first pipeline (32) are simultaneously arranged at an outlet of the ninth pipeline (20), the twentieth pipeline (31) is connected with a first backflow inlet of the catalyst feeding tank (104), and the twenty-first pipeline (32) is connected with a catalyst inlet of the catalyst heater (106).

9. The apparatus for liquid phase nitrobenzene hydrogenation catalyst recycle process according to claim 5, wherein: the new catalyst system of the device for the liquid phase nitrobenzene hydrogenation catalyst recycling process is communicated with a thirteenth line (24) through a seventh line (18) and then with a second line (2).

10. The apparatus for liquid phase nitrobenzene hydrogenation catalyst recycle process according to claim 5, wherein: the device for the liquid-phase nitrobenzene hydrogenation catalyst circulation process is provided with a control device, and the structure is as follows: a seventh automatic valve (V206) is arranged on the fourteenth pipeline (25) and is used for being communicated with the catalyst circulating pipeline; a second automatic valve (V201) is arranged on the twelfth pipeline (23), and a spray head for preventing the catalyst from settling is arranged at the tail end of the twelfth pipeline (23) so as to control the total outlet flow (F201) of the catalyst circulating pump (203); a first flow meter (F202) and a third automatic valve (V202) are sequentially arranged behind the connection point of the twelfth pipeline (23) and the thirteenth pipeline (24) and used for adjusting the flow of the thirteenth pipeline (24); a second flow meter (F203) and a fourth automatic valve (V203) are sequentially arranged on the sixteenth pipeline (27) behind the connection point of the sixteenth pipeline (27) and the seventeenth pipeline (28), and the fourth automatic valve (V203) and the liquid level (L201) of the catalyst circulation tank (201) form a regulating loop for controlling the liquid level of the catalyst circulation tank (201); a thermometer (T202), a fourth flow meter (F205) and a sixth automatic valve (V205) are sequentially arranged on the hot water pipeline (33) and between the outlet of the hot water system and the hot water inlet of the catalyst cooler (202), and the thermometer (T202), the fourth flow meter (F205) and the sixth automatic valve (V205) form a regulating loop for regulating the flow of hot water and controlling the lower temperature (T201) of the catalyst cooler (202); a ninth automatic valve (V208) and a sixth flow meter (F207) are sequentially arranged on the sixth pipeline (12) and in front of the inlet of the catalyst filtering device and are used for controlling the flow entering the catalyst filtering device; a fifth flow meter (F206) and an eighth automatic valve (V207) are sequentially arranged on the twenty-third pipeline (35) and before the liquid phase inlet of the catalyst feeding tank (104) and are used for adjusting and controlling the liquid flow entering the catalyst feeding tank (104); a third flow meter (F204) and a fifth automatic valve (V204) are sequentially arranged on the seventeenth pipeline (28) from the inlet to the outlet and are used for adjusting and controlling the flow entering the catalyst heater (106), a seventh flow meter (F105) and a first automatic valve (V105) are sequentially arranged on the ninth pipeline (20) from the inlet to the outlet, and the seventh flow meter (F105) and the first automatic valve (V105) and the liquid level (L102) of the catalyst feeding tank (104) form an adjusting loop and are used for controlling the liquid level of the catalyst feeding tank (104); a thermometer (T102) was disposed at the outlet of the catalyst heater (106), a thermometer (T101) was disposed at the catalyst feed tank (104), and a thermometer (T104) was disposed on the tenth line (21).