Wacker Chemie Ag

Robert Ring

Norbert Ellinger

Josef Wiesbauer

Uwe Paetzold

Walter Haeckl

Barbara Mueller

Uwe Pätzold

Andreas Hirschmann

Martin Zettl

Bernhard Pfluegler

Bernhard Pflügler

Noemi Banos

The invention relates to a process for hydrogenating silicon tetrachloride in a reactor, wherein a reactant gas containing hydrogen and silicon tetrachloride is heated to a temperature between 850&#xb0; C. and 1600&#xb0; C. by means of at least one heating element, which comprises a graphite surface, wherein the temperature of the heating element is between 850&#xb0; C. and 1600&#xb0; C. The process is characterized in that a nitrogen compound is added to the reactant gas in a substance amount fraction of 0.1 to 10% based on hydrogen.

Process for hydrogenating silicon tetrachloride

A process for producing polysilicon, includes a) depositing polycrystalline silicon on filaments using reaction gas containing silicon-containing component (SCC) containing trichlorosilane, and hydrogen, wherein molar saturation of SCC based on hydrogen is at least 25%; b) feeding offgas from the deposition into a cooling apparatus, i) wherein condensed offgas components containing SiClare conducted to an apparatus which enables distillative purification of the condensate, and ii) non-condensing components are conducted to an adsorption or desorption unit; c) obtaining a first stream of non-condensing components purified by adsorption and containing hydrogen; and d) obtaining, during adsorption unit regeneration, a second stream of non-condensing components, containing SiClwhich is then preferably supplied to a converter for conversion of SiClto trichlorosilane. A process for depositing polysilicon on filaments with a reaction gas includes a SCC and hydrogen, wherein molar saturation of SCC based on hydrogen is at least 25%.

Process for producing polysilicon

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&#xb0; C. and 1300&#xb0; 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.

Process and apparatus for conversion of silicon tetrachloride to trichlorosilane

Disclosed is a method for supplying current to a reactor, wherein electrode(s) of an electrical energy network (EEN), which is DC-isolated from ground potential, is/are fed through a reactor wall and connected to an electrically conductive element (ECE) so that an operating voltage is applied to the ECE and electrical current flows through it. A seal of electrically insulating material is provided between the wall and the electrode. The EEN is monitored for insulation faults. A fall below a particular insulation resistance triggers shutdown of the electrical energy supply. The switching threshold is determined by taking into account at least one of the following parameters: seal geometry, seal material, supply voltage and maximum possible electrical energy input into the seal immediately before shutdown, triggered by the maximum theoretically possible leakage current through the seal. A device and an electrode having respective seals are also disclosed.

Electrode and method for supplying current to a reactor

A device for thermal treatment of corrosive gases includes a chamber for heating gases in which there are at least four heating elements or four groups of heating elements including an electrically conductive material, wherein each heating element or group is connected to a separately regulatable and/or controllable subsystem of an electrical energy network and can thereby be heated by direct current flow, wherein each heating element or group can be controlled or regulated with respect to at least one either identical or different value of a parameter selected from the group consisting of temperature, heating power, current, voltage and resistance, or with respect to another heating element process variable, which can be influenced by the device, and wherein at least four regulatable and/or controllable subsystems are DC-isolated from ground potential. The invention also relates to a corresponding method for the thermal treatment of corrosive gases.

Device and method for the thermal treatment of corrosive gases

High yields of trichlorosilane are achieved in the reaction of tetrachlorosilane and hydrogen at a temperature in the range of 900&#xb0; C. to 1300&#xb0; C. and a pressure above the critical pressure of the reactants.

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Haiming, Germany

Robert Ring