Nitro compound hydrogenation reaction process and hydrogenation reaction apparatus

1 . A hydrogenation reaction process, comprising a hydrogenation step, a regeneration step, an activation step, and a recycling step, wherein:

in the hydrogenation step, nitrobenzene as a reaction raw material is contacted with hydrogen gas and a hydrogenation catalyst in a hydrogenation reactor to obtain aniline and a spent catalyst, wherein the hydrogenation reactor is a fluidized bed reactor, the hydrogenation catalyst is a copper-based catalyst comprising copper as a main active component supported on alumina or silica, and a full inventory of the cooper-based catalyst in the hydrogenation reactor is in contact with the reaction raw material;

in the regeneration step, the spent catalyst is regenerated in a fluidized bed regeneration reactor to obtain a regenerated catalyst;

in the activation step, the regenerated catalyst is activated in a fluidized bed activation reactor to obtain an activated catalyst; and

in the recycling step, the activated catalyst is recycled to the hydrogenation step, wherein the process further comprises:

at least one hydrogenation degassing step of degassing the spent catalyst between the hydrogenation step and the regeneration step,

at least one first regeneration degassing step of degassing the regenerated catalyst between the regeneration step and the activation step,

at least one second regeneration degassing step of degassing the regenerated catalyst between the regeneration step and the recycling step,

at least one activation degassing step of degassing the activated catalyst between the activation step and the recycling step,

and

a catalyst supplement step comprising introducing a supplement hydrogenation catalyst to the activation step,

wherein the particle volume fraction in the unit of % in the transportation pipeline of the spent catalyst being transported from the hydrogenation step to the hydrogenation degassing step is C1, the particle volume fraction in the unit of % in the transportation pipeline of the spent catalyst being transported from the hydrogenation degassing step to the regeneration step is D1, the particle volume fraction in the unit of % in the transportation pipeline of the regenerated catalyst being transported from the regeneration step to the first regeneration degassing step is C2, the particle volume fraction in the unit of % in the transportation pipeline of the regenerated catalyst being transported from the first regeneration degassing step to the activation step is D2, the particle volume fraction in the unit of % in the transportation pipeline of the activated catalyst being transported from the activation step to the activation degassing step is C3, the particle volume fraction in the unit of % in the transportation pipeline of the activated catalyst being transported from the activation degassing step to the recycling step is D3, the particle volume fraction in the unit of % in the transportation pipeline of the regenerated catalyst being transported from the regeneration step to the second regeneration degassing step is C4, the particle volume fraction in the unit of % in the transportation pipeline of the regenerated catalyst being transported from the second regeneration degassing step to the recycling step is D4, the particle volume fraction in the unit of % in the transportation pipeline of the regenerated catalyst or the activated catalyst being transported from the recycling step to the hydrogenation step is C6, and wherein C1, C2, C3, C4, and C6 and D1, D2, D3, and D4 are in the range of 0.5-5%,

wherein the hydrogenation reactor comprises a dense phase reaction zone, at least one dynamic pressure measuring point is mounted on the side wall of the dense phase reaction zone to measure an instantaneous pressure fluctuation in the dense phase reaction zone, and

the catalyst supplement step is initiated when the standard deviation of the instantaneous pressure fluctuation is greater than 600 Pa, or when the catalyst particles having a particle diameter of less than 100 μm account for greater than 3 wt % by mass percent of all catalyst particles in the dense phase reaction zone.

2 . The hydrogenation reaction process according to claim 1 , wherein the supplement hydrogenation catalyst is a copper-based loaded catalyst having an average particle diameter of 5-150 μm.

3 . The hydrogenation reaction process according to claim 1 , wherein the hydrogenation catalyst has a bulk density of 300-1200 kg/m 3 , and/or,

the hydrogenation catalyst has an average particle diameter of 30-800 μm, and the catalyst particles having a particle diameter of less than 80 μm is not less than 2 wt % by mass percent of all catalyst particles.

4 . The hydrogenation reaction process according to claim 1 , wherein the catalyst supplement step is initiated when a response frequency of at least one dynamic pressure measuring point is not less than 100 Hz, and/or when the standard deviation of the instantaneous pressure fluctuation is greater than 1500 Pa, and/or when the catalyst particles having a particle diameter of less than 100 μm comprise greater than 5 wt % by mass percent of all catalyst particles in the dense phase reaction zone.

5 . The hydrogenation reaction process according to claim 2 , wherein the supplement hydrogenation catalyst has an average particle diameter of 20-70 μm.

6 . The hydrogenation reaction process according to claim 3 , wherein the hydrogenation catalyst has an average particle diameter of 50-600 μm, and/or the catalyst particles having a particle diameter of less than 80 μm comprise 5-15 wt % by mass percent of all catalyst particles.

7 . The hydrogenation reaction process according to claim 1 , wherein the average mass flowrate, in kg/h, of the spent catalyst being transported from the hydrogenation step to the hydrogenation degassing step is defined as A1, the average mass flowrate, in kg/h, of the spent catalyst being transported from the hydrogenation degassing step to the regeneration step is defined as B1, the average mass flowrate, in kg/h, of the regenerated catalyst being transported from the regeneration step to the first regeneration degassing step is defined as A2, the average mass flowrate, in kg/h, of the regenerated catalyst being transported from the first regeneration degassing step to the activation step is defined as B2, the average mass flowrate, in kg/h, of the activated catalyst being transported from the activation step to the activation degassing step is defined as A3, the average mass flowrate, in kg/h, of the activated catalyst being transported from the activation degassing step to the recycling step is defined as B3, the average mass flowrate, in kg/h, of the regenerated catalyst or the activated catalyst being transported from the recycling step to the hydrogenation step is defined as A6, then all of A1 to A3, A6 and B1 to B3 are 5-100 kg/h.

8 . The hydrogenation reaction process according to claim 1 , wherein the reaction conditions of the hydrogenation step comprise: the superficial gas velocity is 0.2-0.8 m/s, the molar ratio of hydrogen gas to nitrobenzene is 6-21, the reaction temperature is 220-280° C., the reaction pressure is 0.05-1 MPa, gauge pressure, and/or, the reaction conditions of the regeneration step comprise: in the presence of oxygen-containing gas, the superficial gas velocity is 0.1-0.6 m/s, the reaction temperature is 350-450° C., the reaction pressure is 0.05-1 MPa, gauge pressure, and/or, the reaction conditions of the activation step comprise: in the presence of hydrogen gas, the superficial gas velocity is 0.1-0.6 m/s, the reaction temperature is 200-250° C., the reaction pressure is 0.05-1 MPa, gauge pressure.

9 . The hydrogenation reaction process according to claim 1 , wherein the dimensionless particle diameter of the hydrogenation reactor is in the range of 1-60, and/or, the dimensionless particle diameter of the regeneration reactor is in the range of 1-40, and/or, the dimensionless particle diameter of the activation reactor is in the range of 1-30, wherein the dimensionless particle diameter is determined by the following equation:

Dimensionless

⁢

particle

⁢

diameter

=

Average

⁢

particle

⁢

diameter

×

Gas

⁢

density

×

Gas

-

solid

⁢

density

⁢

difference

×

g

Gas

⁢

kinetic

⁢

viscosity

2

3

,

wherein, the average particle diameter is the volume average particle diameter, in m, of solid particles in the reactor, the gas density is the density, in kg/m 3 , of the gas in the reactor, the gas-solid density difference is the difference of the density, in kg/m 3 , of solid particles minus the density, in kg/m 3 , of the gas in the reactor, the gas kinetic viscosity is the kinetic viscosity, in Pa·s, of the gas in the reactor, and g is the absolute value of the gravity acceleration of 9.8 m/s 2 .

10 . The hydrogenation reaction process according to claim 1 , wherein in the catalyst supplement step, the ratio of the average mass flowrate of the supplement hydrogenation catalyst being transported to the hydrogenation catalyst inventory in the hydrogenation reactor, in kg, is less than 10 h −1 .

11 . The hydrogenation reaction process according to claim 1 , wherein in the catalyst supplement step, the ratio of the average mass flowrate of the supplement hydrogenation catalyst being transported to the hydrogenation catalyst inventory in the hydrogenation reactor, in kg, is 0.00002-0.001 h −1 .