System and Method for Controlling the System for the Production of Polycrystalline Silicon
A system and a method for the production of polycrystalline silicon according to the monosilane process are disclosed. At least one reactor ( 10 ), at least one converter ( 20 ), at least one injection tank ( 30 ) and at least one vaporizer ( 40 ) are provided. Each reactor ( 10 ) is provided with an inlet pipe ( 11 a ) for fresh mixtures of gases and an outlet pipe ( 11 b ) for partially used-up mixtures of gases. Likewise, each converter ( 20 ) comprises an outlet pipe ( 21 ) for a mixture of gases and each vaporizer ( 40 ) comprises an outlet pipe ( 41 ) for a mixture of gases. Several sampling elements ( 7 ) for specimens to be measured are provided in the inlet pipe ( 11 a ) and the outlet pipe ( 11 b ) of each reactor ( 10 ) as well as in the outlet pipe ( 21 ) of each converter ( 20 ) and the outlet pipe ( 41 ) of each vaporizer ( 40 ). The withdrawn specimens to be measured are fed by the sampling elements ( 7 ) via a pipe ( 8 ) to at least one gas-phase chromatograph ( 2 ).
1 . A system for the production of polycrystalline silicon comprising:
at least one reactor;
in each case a sampling element for specimens to be measured is provided in an inlet pipe and an outlet pipe of the at least one reactor;
at least one gas-phase chromatograph for analyzing the withdrawn specimens; and
a pipe connects each sampling element and the gas-phase chromatograph.
2 . The system of claim 1 , wherein at least one converter and/or at least one injection tank and/or at least one vaporizer are provided in addition to the at least one reactor, that each reactor is provided with the inlet pipe for fresh mixtures of gases and the outlet pipe for partially used-up mixtures of gases, that each converter is provided with an outlet pipe for a mixture of gases and each vaporizer is provided with an outlet pipe for a mixture of gases, wherein the outlet pipe of the vaporizer is the inlet pipe for the converter and that likewise a sampling element is provided in the outlet pipe of the converter and a sampling element is provided in the outlet pipe for the vaporizer.
3 . The system of claim 2 , wherein in each case a pipe from each of the sampling elements is connected with the gas-phase chromatograph.
4 . The system of claim 3 , wherein the pipes leading from the sampling elements to the at least one gas-phase chromatograph are heated, so that the withdrawn samples are in a gaseous state.
5 . The system of claim 1 , wherein a sample recirculation is connected in the system downstream of the at least one gas-phase chromatograph, wherein the sample recirculation is designed in such a way that the recirculated mixture of gases in the sample recirculation is at a pressure which is in accordance with the pressure in the outlet pipe of the at least one reactor.
6 . The system of claim 5 , wherein a reprocessing system for gas is provided, which is connected with the outlet pipe of the reactor and with an outlet pipe of the vaporizer, wherein the outlet pipe also transports the gas from the outlet pipe of the at least one converter.
7 . The system of claim 1 , wherein a control unit is provided, which receives signals from the analysis of the withdrawn specimens to be measured and generates control signals thereof, which act on at least one actuator, which is related to the at least one reactor ( 10 ) and/or at least one vaporizer and/or at least one converter and/or at least one injection tank and wherein the process parameters are automatically adjusted by means of the actuators.
8 . The system of claim 7 , wherein the actuator in the inlet pipe to the at least one reactor is a valve, with which the supply of reaction gas into the at least one reactor is automatically controllable due to the measuring signals of the gas-phase chromatograph.
9 . A method for controlling a system for the production of polycrystalline silicon, wherein the system has at least one reactor with at least one inlet pipe and an outlet pipe for a mixture of gases, comprising the following steps:
withdrawing specimens to be measured from the inlet pipe and the outlet pipe of each reactor;
feeding the withdrawn specimens to be measured to at least one gas-phase chromatograph via a pipe;
obtaining controlling signals on the basis of the measurements with respect to the composition of the fed specimens to be measured obtained by the gas-phase chromatograph; and
adjusting a plurality of parameters of the at least one reactor on the basis of the obtained controlling signals by means of a control unit via actuators n such a way that the efficiency of the system automatically results in a production optimum.
10 . The method of claim 9 , wherein at least a converter and/or at least an injection tank and/or at least a vaporizer are provided in addition to the at least one reactor, that each reactor comprises the inlet pipe for fresh mixtures of gases and the outlet pipe for partially exhausted mixtures of gases, that each converter comprises an outlet pipe for a mixture of gases and each vaporizer an outlet pipe for a mixture of gases, wherein the outlet pipe of the vaporizer is the inlet pipe for the converter and that likewise a sampling element is provided in the outlet pipe of the converter and a sampling element is provided in the outlet pipe for the vaporizer.
11 . The method of claim 10 , wherein the specimens to be measured are withdrawn by sampling elements and fed via the pipes, which are heated, to the at least one gas-phase chromatograph.
12 . The method of claim 9 , wherein a sample recirculation is connected in the system downstream of the at least one gas-phase chromatograph, wherein the sample recirculation is designed in such a way that the recirculated mixture of gases in the sample recirculation is at a pressure which is in accordance with the pressure in the outlet pipe of the at least one reactor.
13 . The method of claim 9 , wherein the at least one gas-phase chromatograph tests any existence of water in the system when putting the system into operation and that afterwards the parameters of the at least one reactor and/or of the at least one converter and/or of the at least one vaporizer are adjusted and altered in such a way when commissioning the system that an automatic start-up of the system on the process conditions is carried out due to the controlling signals obtained by means of the at least one gas-phase chromatograph.
14 . The method of claim 9 , wherein a control unit is provided, which receives signals from the analysis of the withdrawn specimens to be measured and generates control signals thereof, which impact on at least one actuator, which is related to the at least one reactor and/or the at least one vaporizer and/or the at least one converter and/or the at least one injection tank and wherein the process parameters are automatically adjustable by means of the actuators.
15 . The method of claim 14 , wherein the actuator in the inlet pipe to the at least one reactor is a valve, with which the supply of reaction gas into the at least one reactor is automatically controllable due to the measuring signals of the gas-phase chromatograph.