| 초록 |
Carbon fibers (CF) are often produced from polyacryonitrile (PAN) fiber precursors through a series of thermal processing steps, including stabilization, low temperature carbonization, and high temperature carbonization. In order to avoid thermal shock of fibers, low temperature heat treatment, usually at 300–800◦C, is applied prior to high temperature carbonization, which is very conducive to improvement in tensile strength or in Young’s modulus of the final carbon fiber. The low temperature furnace (LTF) as a tar removal furnace comprises electrically heated multi-zone slots, purged with N2 to prevent ingress of air and providing sufficient N2 flow to remove off-gas (HCN, NH3, N2, H2O, CO2, CO, CH4, and H2). The ventilation of off-gas and uniform temperature over the CF tows play an important role in the low temperature carbonization process. This study aims to develop a three dimensional (3D) CFD model of the LTF with off-gas emission rates as a function of temperature. The residence time of off-gas, the dead-zone ratio of gas velocity, and the uniformity of temperature are proposed as the performance criteria of the LTF to find optimal duct position. |
