Methods and systems for hcn removal

Abstract

Hydrogen cyanide removal during transformation of a carbon fiber precursor into carbon fiber is provided. The method may comprise heating a carbon fiber body precursor at a substantially atmospheric pressure to above about 1200° C. in a furnace in a first stage, expelling a stream of effluent gas outside the furnace, wherein the stream of effluent gas comprises a cyanide, thermally oxidizing the cyanide during the first stage, and heating the carbon fiber body precursor to a temperature of between about 1600° C. and about 2200° C. in a second stage.

1 . A method of transforming a carbon fiber body precursor into a carbon fiber body, comprising:
 heating a carbon fiber body precursor to a temperature of above about 1200° C. and a pressure of about 1 atm to about 1.5 atm in a furnace in a first stage;   expelling a stream of effluent gas outside the furnace, wherein the stream of effluent gas comprises a cyanide;   thermally oxidizing the cyanide during the first stage; and   heating the carbon fiber body precursor to a temperature of between about 1600° C. and about 2400° C. in a second stage.   
     
     
         2 . The method of  claim 1 , further comprising drawing a vacuum using a steam vacuum prior to entering the second stage. 
     
     
         3 . The method of  claim 1 , wherein the first stage temperature does not exceed about 1600° C. 
     
     
         4 . The method of  claim 1 , wherein the thermal oxidation occurs in an incinerator. 
     
     
         5 . The method of  claim 1 , wherein a secondary gas is pumped into the furnace during the expelling of the stream of effluent gas. 
     
     
         6 . The method of  claim 1 , wherein the secondary gas is at least one of nitrogen and argon. 
     
     
         7 . The method of  claim 1 , wherein the first stage temperature is between about 1200° C. to about 1300° C. 
     
     
         8 . The method of  claim 1 , wherein the cyanide is hydrogen cyanide. 
     
     
         9 . A system comprising for transforming a carbon fiber body precursor into a carbon fiber body, comprising:
 a furnace having a gas inlet;   a thermal oxidizer in fluid communication with the furnace;   wherein the furnace is capable of heating a carbon fiber body precursor to above about 1200° C. in a first stage at a pressure of about 1 atm to about 1.5 atm;   wherein a stream of effluent gas is expelled outside the furnace in response to the furnace reaching a temperature of above about 1200° C.;   wherein the stream of effluent gas comprises a cyanide; and   wherein the thermal oxidizer oxidizes the cyanide during the first stage.   
     
     
         10 . The system of  claim 9 , further comprising a steam vacuum. 
     
     
         11 . The system of  claim 9 , wherein the first stage temperature does not exceed about 1600° C. 
     
     
         12 . The system of  claim 9 , wherein the thermal oxidizer comprises an incinerator. 
     
     
         13 . The system of  claim 9 , wherein secondary a gas is pumped into the inlet. 
     
     
         14 . The system of  claim 13 , wherein the secondary gas is at least one of nitrogen and argon. 
     
     
         15 . The system of  claim 9 , wherein the first stage temperature is between about 1200° C. to about 1300° C. 
     
     
         16 . The system of  claim 1 , wherein the cyanide is hydrogen cyanide. 
     
     
         17 . A method of transforming a carbon fiber body precursor into a carbon fiber body, comprising:
 heating the carbon fiber body precursor at a substantially atmospheric pressure to above about 1200° C. in a furnace in a first stage;   introducing a secondary gas into the furnace at a positive pressure;   expelling a stream of effluent gas outside the furnace, wherein the stream of effluent gas comprises a cyanide;   thermally oxidizing the cyanide during the first stage using a thermal oxidizer;   closing a first valve so that the thermal oxidizer is no longer in fluid communication with the furnace;   opening a second valve in fluid communication with a steam vacuum so that the steam vacuum becomes in fluid communication with the furnace; and   heating the carbon fiber body precursor to a temperature of between about 1600° C. and about 2200° C. in a second stage.   
     
     
         18 . The method of  claim 17 , wherein the thermal oxidizer is an incinerator. 
     
     
         19 . The method of  claim 17 , wherein the secondary gas is nitrogen gas. 
     
     
         20 . The method of  claim 17 , further comprising using the steam vacuum to form a vacuum in the furnace.