Process for preparing chlorosilanes

Patent metadata

Field	Value
Publication number	US-12129177-B2
Application number	US-201817309795-A
Country	US
Kind code	B2
Filing date	Dec 18, 2018
Priority date	Dec 18, 2018
Publication date	Oct 29, 2024
Grant date	Oct 29, 2024

Abstract

The present disclosure relates to a process for producing chlorosilanes in a fluidized bed reactor by reaction of a hydrogen and silicon tetrachloride-containing reaction gas with a particulate contact mass containing silicon and a catalyst. The chlorosilanes have the general formula H n SiCl 4-n and/or H m Cl 6-m Si 2 . The reactor design is described by an index K1, the constitution of the contact mass is described by an index K2 and the reaction conditions are described by an index K3.

First claim

The invention claimed is:

1. A process for producing chlorosilanes in a fluidized bed reactor, comprising: reacting a hydrogen and silicon tetrachloride-containing reaction gas with a particulate contact mass containing silicon and a catalyst, wherein the chlorosilanes have the general formula H n SiCl 4-n and/or H m Cl 6-m Si 2 where n=1-3 and m=0-4, and
wherein the reactor design is described by an index

K
⁢
1

=

φ
·

V

reactor
,
eff

A

tot
,
cooled

·

d
hyd

;

wherein φ is a fill level of the reactor;
wherein V reactor, eff is an effective volume of the reactor [m 3 ];
wherein A tot, cooled is a sum of cooled surface areas in the reactor [m 2 ];
wherein d hyd is a hydraulic reactor diameter [m]; and
wherein V reactor, eff is 1 to 300 m 3 ; and
wherein d hyd is 0.5 to 2.5 m;

wherein the constitution of the contact mass is described by an index

K
⁢
2

=

R

S
⁢
i

·

B

A
⁢
K

·

δ

r
⁢
e
⁢
l

d

3
⁢
2

;

wherein B AK is a breadth of the particle size distribution of the contact mass [μm];
wherein d 32 is a particle Sauter diameter [μm];
wherein R Si is a purity of the silicon;
wherein δ rel is a relative catalyst distribution in the contact mass;
wherein δ rel is 0.001 to 7;
wherein d 32 is 10 to 2000 μm;
wherein B AK is 10 to 1500 μm; and
wherein R Si is 0.75 to 0.99999;

wherein the reaction conditions are described by an index

K
⁢
3

=

u
L

v
F

·

10
6

·

p
diff

g

·

1

ρ
F

;

wherein u L is a superficial gas velocity [m/s];
wherein v F is a kinematic viscosity of a gaseous reaction mixture within an interior of the reactor [m 2 /s];
wherein ρ F is a fluid density [kg/m 3 ];
wherein p diff is a pressure drop over fluidized bed [kg/m*s 2 ];
wherein g is an acceleration due to gravity [m/s 2 ];
wherein p diff is 10 000 to 200 000 kg/m*s 2 ;
wherein u L is 0.05 to 2 m/s;
wherein ρ F is 2 to 20 kg/m 3 ;
wherein v F is 3*10 −7 to 5.4*10 −6 m 2 /s; and
wherein K1 has a value of 2 to 20, wherein K2 has a value of 0.001 to 200 and

wherein K3 has a value of 0.5 to 10 000.

2. The process of claim 1 , wherein K1 has a value of 3 to 18.

3. The process of claim 1 , wherein K2 has a value of 0.005 to 100.

4. The process of claim 1 , wherein K3 has a value of 0.5 to 10,000.

5. The process of claim 1 , wherein the effective reactor volume V reactor, eff is 5 to 200 m 3 .

6. The process of claim 1 , wherein the hydraulic plant diameter d hyd is 0.75 to 2 m.

7. The process of claim 1 , wherein the pressure drop over the fluidized bed p diff is 30,000 to 150,000 kg/m*s 2 .

8. The process of claim 1 , wherein the particle Sauter diameter d 32 is 50 to 1500 μm.

9. The process of claim 1 , wherein the breadth of the particle size distribution of the contact mass B AK is 100 to 1000 μm.

10. The process of claim 1 , wherein the relative catalyst distribution in the contact mass δ rel is 0.005 to 5.

11. The process of claim 1 , wherein the catalyst is selected from the group of Fe, Al, Ca, Ni, Mn, Cu, Zn, Sn, C, V, Ti, Cr, B, P, O, Cl and mixtures thereof.

12. The process of claim 1 , wherein the superficial gas velocity u L is 0.1 to 1 m/s.

13. The process of claim 1 , wherein the fluid density ρ F is 5 to 15 kg/m 3 .

14. The process of claim 1 , wherein the kinematic viscosity v F is 1.5*10 −6 to 5.4*10 −6 m 2 /s.

15. The process of claim 1 , wherein the absolute pressure in the fluidized bed reactor is 0.5 to 5 MPa.

16. The process of claim 1 , wherein the reaction is performed in a temperature range of 350° C. to 800° C.

17. The process of claim 1 , wherein the reaction gas contains, before entering the reactor, at least 10 vol % of hydrogen and silicon tetrachloride.

18. The process of claim 1 , wherein the fluidized bed reactor is integrated into an integrated system for production of polycrystalline silicon.

19. The process of claim 1 , wherein wherein A tot, cooled is a sum of cooled surface areas as determined by laser measurements or 3D scans in the reactor [m 2 ]; or
wherein B AK is d 90 -d 10 ; or
wherein the ca

Assignees

• Wacker Chemie Ag

Inventors

• Rimboeck Karl-Heinz

Classifications

• B01J2208/00796

  Details of the reactor or of the particulate material · CPC title

• B01J2208/00672

  Particle size selection · CPC title

• B01J2208/00584

  Controlling the density · CPC title

• B01J2208/00575

  Controlling the viscosity · CPC title

• B01J2208/00548

  Flow · CPC title