Chemical reactor with knitted wire mesh fabric as a holding device for particles

1. A chemical reactor for heterogeneously catalysed reaction of a fluid, comprising a holding device for particles through which the fluid flows, wherein a side of the holding device lying upstream when viewed in a direction of flow of the fluid comprises a first knitted wire mesh fabric, and an average clear mesh width of the first knitted wire fabric is smaller than an average particle size x 50.3 of the particles,

wherein said first knitted wire mesh fabric is arranged on a support and the support comprises continuous openings in a direction of flow of the fluid, and

wherein a second knitted wire mesh fabric is additionally arranged between the support and a wall of the reactor.

2. The reactor according to claim 1 , wherein the average clear mesh width of said first knitted wire is from ≧20% to ≦80% of the average particle size x 50.3 of the particles.

3. The reactor according to claim 1 , wherein extensibility of said first knitted wire mesh fabric under exposure to mechanical and/or thermal stress in a planar direction is ≧1%.

4. The reactor according to claim 1 , wherein a wire diameter of said first knitted wire mesh fabric is from ≧0.03 mm to ≦1 mm.

5. The reactor according to claim 1 , wherein a height of said first knitted wire mesh fabric in the holding device for particles is from ≧3 mm to ≦100 mm.

6. The reactor according to claim 1 , wherein said first knitted wire mesh fabric is a knitted wire mesh fabric deformed by mechanical action.

7. The reactor according to claim 1 , wherein said particles comprise catalyst particles that are arranged on the first knitted wire mesh fabric in the holding device.

8. The reactor according to claim 1 , wherein a layer of particles which are inert towards the fluid is arranged on the first knitted wire mesh fabric in the holding device and catalyst particles are arranged on said layer of particles which are inert towards the fluid.

9. A process for reaction of a fluid, comprising carrying out a reaction in a reactor according to claim 1 , in the presence of heterogeneous catalyst particles wherein the catalyst particles are arranged in the holding device, and wherein the fluid comprises aromatic nitro compounds and hydrogen.

10. The process according to claim 9 , wherein when the reaction has ended, the reactor continues to be heated at a temperature of from ≧200° C. to ≦400° C. in the presence of oxygen.

11. The process according to claim 9 , wherein the reaction is carried out adiabatically.

12. The reactor according to claim 1 , further comprising a metallic gasket of mesh fabric.

13. The reactor according to claim 1 , wherein the second knitted wire mesh fabric additionally arranged between a support and a wall of the reactor is arranged in a U-shaped form and an elastically pretensioned further knitted wire mesh fabric is incorporated in a depression thereby formed.

14. The reactor according to claim 1 , wherein the first knitted fabric of said knitted wire is steel, high-grade steel, copper, monel, or aluminum.

15. The reactor according to claim 1 , wherein the ratio between the mesh length and mesh width of said first knitted wire is between 4:1 and 0.5:1.

16. The reactor according to claim 1 , wherein said support is a simple slotted screen or a simple grating.

17. A chemical reactor for heterogeneously catalysed reaction of a fluid, comprising a holding device for particles through which the fluid flows, wherein a side of the holding device lying upstream when viewed in a direction of flow of the fluid comprises knitted wire mesh fabric, and an average clear mesh width of the knitted wire fabric is smaller than an average particle size x 50.3 of the particles,

wherein a layer of particles which are inert towards the fluid is arranged on the knitted wire mesh fabric in the holding device and catalyst particles are arranged on said layer of particles which are inert towards the fluid.

18. The reactor according to claim 17 , wherein the average clear mesh width of said knitted wire is from ≧20% to ≦80% of the average particle size x 50.3 of the particles.

19. The reactor according to claim 17 , wherein extensibility of said knitted wire mesh fabric under exposure to mechanical and/or thermal stress in a planar direction is ≧1%.

20. The reactor according to claim 17 , wherein a wire diameter of said knitted wire mesh fabric is from ≧0.03 mm to ≦1 mm.

21. The reactor according to claim 17 , wherein a height of said knitted wire mesh fabric in the holding device for particles is from ≧3 mm to ≦100 mm.

22. The reactor according to claim 17 , wherein said knitted wire mesh fabric is a knitted wire mesh fabric deformed by mechanical action.

23. The reactor according to claim 17 , wherein said knitted wire mesh fabric is arranged on a support and the support comprises continuous openings in a direction of flow of the fluid.

24. A process for reaction of a fluid, comprising carrying out a reaction in a reactor according to claim 17 , in the presence of heterogeneous catalyst particles wherein the catalyst particles are arranged in the holding device, and wherein the fluid comprises aromatic nitro compounds and hydrogen.

25. The process according to claim 24 , wherein when the reaction has ended, the reactor continues to be heated at a temperature of from ≧200° C. to ≦400° C. in the presence of oxygen.

26. The process according to claim 24 , wherein the reaction is carried out adiabatically.