PURPOSE: To obtain graphitized carbon fiber by reducing the amount of produced hydrogen cyanide, etc., even if produced, enabling the discharge thereof to the outside of a furnace at a low concentration and carrying out the operation of a graphitizing furnace with nitrogen gas as an inert gas for the graphitizing furnace.
CONSTITUTION: The feed rate (Qa+Qb) of nitrogen gas in gas curtain sealing parts (1A) and (1B) at the inlet and the outlet of a graphitizing furnace 1 is increased to feed the nitrogen gas under conditions of a reduced feed rate (Qc) in a graphite heating element part (1C). Thereby, the interior of the furnace is an inert gas atmosphere to heat the carbonized fiber (F). As a result, the fiber is graphitized. Nitrogen in the furnace 1 is made to react with carbon in the heating element part (1C) and hydrocarbons, hydrogen, etc., from the fiber by heating with the graphite heating element part (1C) to produce cyanogen or hydrogen cyanide. The feed rate (Qc) of the nitrogen gas to the heating element part (1C) is reduced to reduce the amount of hydrogen cyanide, etc., produced in the heating element part (1C) and the concentration in the waste gas can be reduced.
CHIBA YOSHIMASA
OMAE HIROYUKI
HINO TAKASHI
YAMAMOTO MASAHARU
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