Purification method and purification apparatus for off-gas

Abstract

The present invention relates to a purification method and a purification apparatus for off-gas. More specifically, the present invention relates to a purification method and a purification apparatus for off-gas, capable of lowering the concentration of hydrogen chloride and separating high-purity hydrogen from the off-gas, which is discharged after performing a polysilicon deposition process by a chemical vapor deposition reaction.

1 . A purification method for off-gas which comprises the steps of:
 passing the off-gas, which is discharged after performing a polysilicon deposition process by a chemical vapor deposition (CVD) reaction, through a catalytic reactor containing an ion exchange resin catalyst to lower the concentration of hydrogen chloride; and   passing the off-gas through the catalytic reactor and then separating hydrogen and chlorosilane-based compounds contained in the passed off-gas.   
     
     
         2 . The purification method for off-gas according to  claim 1 , wherein the ion exchange resin catalyst includes a cyclic amine compound, a styrene-based polymer containing an amine group, a styrene-divinyl benzene-based polymer containing an amine group, an acrylic polymer containing an amine group, or mixtures thereof. 
     
     
         3 . The purification method for off-gas according to  claim 1 , wherein the off-gas includes hydrogen chloride (HCl), hydrogen (H 2 ) and chlorosilane-based compounds. 
     
     
         4 . The purification method for off-gas according to  claim 1 , wherein the content of hydrogen chloride occupied in the off-gas which has been passed through the catalytic reactor is reduced to about 80 mol % or more, with respect to the content before passing through the catalytic reactor. 
     
     
         5 . The purification method for off-gas according to  claim 1 , wherein the off-gas is converted into trichlorosilane and silicon tetrachloride by passing through the catalytic reactor. 
     
     
         6 . A purification apparatus for off-gas which comprises:
 a catalytic reactor that contains an ion exchange resin catalyst, and lowers the concentration of hydrogen chloride by passing the off-gas, which is discharged after performing a polysilicon deposition process by a chemical vapor deposition (CVD) reaction; and   a separation device that separates hydrogen and a chlorosilane-based compound from the off-gas passed through the catalytic reactor.   
     
     
         7 . The purification apparatus for off-gas according to  claim 6 , wherein the ion exchange resin catalyst includes a cyclic amine compound, a styrene-based polymer containing an amine group, a styrene-divinyl benzene-based polymer containing an amine group, an acrylic polymer containing an amine group, or mixtures thereof. 
     
     
         8 . The purification apparatus for off-gas according to  claim 6 , wherein the separation device includes one or more selected from the group consisting of a knock-out drum, a distillation device, a separation membrane device, and a gas-liquid separation device. 
     
     
         9 . A purification method for off-gas which comprises the steps of:
 separating the off-gas, which is discharged after performing a polysilicon deposition process by a chemical vapor deposition (CVD) reaction, into a non-condensed phase stream and a condensed phase stream; and   passing the condensed phase stream through a catalytic reactor including an ion exchange resin catalyst to lower the concentration of hydrogen chloride.   
     
     
         10 . The purification method for off-gas according to  claim 9 , wherein the ion exchange resin catalyst includes a cyclic amine compound, a styrene-based polymer containing an amine group, a styrene-divinyl benzene-based polymer containing an amine group, an acrylic polymer containing an amine group, or mixtures thereof. 
     
     
         11 . The purification method for off-gas according to  claim 9 , wherein the off-gas includes hydrogen chloride (HCl), hydrogen (H 2 ), and chlorosilane-based compounds. 
     
     
         12 . The purification method for off-gas according to  claim 9 , wherein the content of hydrogen chloride occupied in the condensed phase stream which has been passed through the catalytic reactor is reduced to about 80 mol % or more, with respect to the content before passing through the catalytic reactor. 
     
     
         13 . The purification method for off-gas according to  claim 9 , wherein the condensed phase stream is converted into trichlorosilane and silicon tetrachloride by passing through the catalytic reactor. 
     
     
         14 . The purification method for off-gas according to  claim 9 , wherein, after passing the condensed phase stream through the catalytic reactor, a step of separating the chlorosilane-based compound contained in the passed condensed phase stream is further included. 
     
     
         15 . A purification apparatus for off-gas which comprises:
 a separation device that separates the off-gas, which is discharged after performing a polysilicon deposition process by a chemical vapor deposition (CVD) reaction, into a non-condensed phase stream and a condensed phase stream; and   a catalytic reactor that contains an ion exchange resin catalyst and lowers the concentration of hydrogen chloride from the condensed phase stream.   
     
     
         16 . The purification apparatus for off-gas according to  claim 15 , wherein the ion exchange resin catalyst includes a cyclic amine compound, a styrene-based polymer containing an amine group, a styrene-divinyl benzene-based polymer containing an amine group, an acrylic polymer containing an amine group, or mixtures thereof. 
     
     
         17 . The purification method for off-gas according to  claim 15 , wherein the separation device includes one or more selected from the group consisting of a knock-out drum, a distillation device, a separation membrane device, a gas-liquid separation device, an absorption column and an adsorption column. 
     
     
         18 . The purification method for off-gas according to  claim 15 , further comprising a first cooler which is located at the front end of the separation device and cools the off-gas.