Process and apparatus for conversion of silicon tetrachloride to trichlorosilane

Patent metadata

Field	Value
Publication number	US-9480959-B2
Application number	US-201213979268-A
Country	US
Kind code	B2
Filing date	Jan 16, 2012
Priority date	Jan 17, 2011
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

Abstract

A process for hydrogenating chlorosilanes in a reactor, wherein at least two reactant gas streams are introduced separately from one another into a reaction zone, wherein the first reactant gas stream comprising silicon tetrachloride is conducted via a first heat exchanger unit in which it is heated and is then conducted through a heating unit which heats it to a first temperature before the first reactant gas stream reaches the reaction zone, and wherein the second reactant gas stream comprising hydrogen is heated by a second heat exchanger unit to a second temperature, wherein the first temperature is greater than the second temperature, and then introduced into the reaction zone, such that the mixing temperature of the two reactant gas streams in the reaction zone is between 850° C. and 1300° C., and said reactant gas streams react to give product gases comprising trichlorosilane and hydrogen chloride, wherein the product gases obtained in the reaction are conducted through said at least two heat exchanger units and preheat the reactant gas streams of the reaction by the countercurrent principle, wherein the flow passes first through the first heat exchanger unit and then through the second heat exchanger unit. A reactor for hydrogenating chlorosilanes, comprising two gas inlet devices through which reactant gases can be introduced separately from one another into the reactor, and at least one gas outlet device through which a product gas stream can be conducted, at least two heat exchanger units which are connected to one another and which are suitable for heating reactant gases separately from one another by means of the product gases conducted through the heat exchanger units, and a heating zone which is arranged between a first heat exchanger unit and a reaction zone and in which there is at least one heating element.

First claim

The invention claimed is:

1. A process for hydrogenating chlorosilanes in a reactor, wherein at least two reactant gas streams are introduced separately from one another into a reaction zone, wherein a first reactant gas stream comprising silicon tetrachloride is conducted through a first heat exchanger unit in which it is heated and is then conducted through a heating unit which heats the first reactant gas stream to a first temperature before the first reactant gas stream reaches the reaction zone, and wherein a second reactant gas stream comprising hydrogen is heated by a second heat exchanger unit to a second temperature, wherein the first temperature is greater than the second temperature, and then introduced into the reaction zone, such that a mean gas temperature in the reaction zone is from 850° C. to 1300° C., and said at least two reactant gas streams react to give product gases comprising trichlorosilane and hydrogen chloride, wherein the product gases obtained in the reaction are conducted in a product gas stream through said at least two heat exchanger units and preheat the at least two reactant gas streams of the reaction by a countercurrent principle, wherein the product gas stream passes first through the first heat exchanger unit and then through the second heat exchanger unit.

2. The process as claimed in claim 1 , wherein dichlorosilane is additionally introduced into a reaction space with a molar ratio based on silicon tetrachloride of 0.5% to 20%.

3. The process as claimed in claim 1 , wherein the first heat exchanger unit comprises graphite, silicon carbide, silicon carbide-coated graphite, silicon nitride, CFC or silicon carbide-coated CFC, and the second heat exchanger unit comprises steel or stainless steel.

4. The process as claimed in claim 1 , wherein a pressure of the first reactant gas stream in the first heat exchanger unit is 10 to 1000 mbar higher than the pressure of the product gas stream as it flows through the first heat exchanger unit.

5. The process as claimed in claim 2 , wherein the first heat exchanger unit comprises graphite, silicon carbide, silicon carbide-coated graphite, silicon nitride, CFC or silicon carbide-coated CFC, and the second heat exchanger unit comprises steel or stainless steel.

6. The process as claimed in claim 5 , wherein a pressure of the first reactant gas stream in the first heat exchanger unit is 10 to 1000 mbar higher than the pressure of the product gas stream as it flows through the first heat exchanger unit.

Assignees

• Ring Robert
• Banos Noemi
• Paetzold Uwe
• Wacker Chemie Ag

Inventors

• Ring Robert
• Banos Noemi
• Paetzold Uwe

Classifications

• Y02P20/129

  Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines · CPC title

• C01B33/1071 Primary

  Tetrachloride, trichlorosilane or silicochloroform, dichlorosilane, monochlorosilane or mixtures thereof · CPC title

• C01B33/04

  Hydrides of silicon · CPC title

• B01J12/00 Primary

  Chemical processes in general for reacting gaseous media with gaseous media; Apparatus specially adapted therefor (B01J3/08, B01J8/00, B01J19/08 take precedence) · CPC title

• C01B33/107 Primary

  Halogenated silanes · CPC title