회분식 스티렌 현탁중합 반응공정에서 단량체(스티렌, M)와 분산매(물, W)의 질량비를 1~3으로, 개시제(BPO, I) 농도를 1~3 wt%으로, 그리고 단량체 질량을 125~165 g으로 각각 변화시키면서 시간에 따른 반응온도를 측정하고, 최대 발열온도, 최대 발열시간 및 최대 발열속도를 산출하여 반응폭주에 미치는 조업조건의 영향을 해석하였다. 실험결과, 일정한 단량체 질량에서 M/W의 질량비가 감소할수록 물의 높은 ...
회분식 스티렌 현탁중합 반응공정에서 단량체(스티렌, M)와 분산매(물, W)의 질량비를 1~3으로, 개시제(BPO, I) 농도를 1~3 wt%으로, 그리고 단량체 질량을 125~165 g으로 각각 변화시키면서 시간에 따른 반응온도를 측정하고, 최대 발열온도, 최대 발열시간 및 최대 발열속도를 산출하여 반응폭주에 미치는 조업조건의 영향을 해석하였다. 실험결과, 일정한 단량체 질량에서 M/W의 질량비가 감소할수록 물의 높은 열적 안정성에 의해 최대 발열시간은 지연되었고 최대 발열온도와 최대 발열속도는 감소하였다. 또한 개시제 농도가 증가할수록 최대 발열시간은 감소하고 최대 발열온도와 최대 발열속도는 증가하여 반응폭주의 위험성이 증가하였다. 그리고 일정한 M/W 비와 개시제 농도에서는 단량체의 질량이 증가할수록 발열개시시간은 다소 감소하였으나 최대 발열속도는 크게 변화하지 않았다. 자유라디칼중합반응 속도론에 의한 물질 수지식 및 에너지 수지식으로 부터 산출한 이론값은 최대 발열온도에서 실험값과 다소 차이가 있었으나 발열개시시간은 거의 일치하였다. 이때 반응폭주는 온도곡선과 유사한 형태를 갖는 성장단계의 반응속도상수에 크게 영향을 받으며 약 70%의 반응 전화율에서 발생하여 단량체 농도와 개시제 농도가 각각 급격하게 감소 또는 증가함을 알 수 있었다. 또한 제시된 모델식을 사용하여 모사한 결과, 본 실험조건에서는 약 M/W 비가 약 0.5이하, 개시제 농도가 약 3 wt%, 그리고 냉각온도가 75℃이하에서 반응폭주의 발생을 억제할 수 있었다.
회분식 스티렌 현탁중합 반응공정에서 단량체(스티렌, M)와 분산매(물, W)의 질량비를 1~3으로, 개시제(BPO, I) 농도를 1~3 wt%으로, 그리고 단량체 질량을 125~165 g으로 각각 변화시키면서 시간에 따른 반응온도를 측정하고, 최대 발열온도, 최대 발열시간 및 최대 발열속도를 산출하여 반응폭주에 미치는 조업조건의 영향을 해석하였다. 실험결과, 일정한 단량체 질량에서 M/W의 질량비가 감소할수록 물의 높은 열적 안정성에 의해 최대 발열시간은 지연되었고 최대 발열온도와 최대 발열속도는 감소하였다. 또한 개시제 농도가 증가할수록 최대 발열시간은 감소하고 최대 발열온도와 최대 발열속도는 증가하여 반응폭주의 위험성이 증가하였다. 그리고 일정한 M/W 비와 개시제 농도에서는 단량체의 질량이 증가할수록 발열개시시간은 다소 감소하였으나 최대 발열속도는 크게 변화하지 않았다. 자유라디칼 중합반응 속도론에 의한 물질 수지식 및 에너지 수지식으로 부터 산출한 이론값은 최대 발열온도에서 실험값과 다소 차이가 있었으나 발열개시시간은 거의 일치하였다. 이때 반응폭주는 온도곡선과 유사한 형태를 갖는 성장단계의 반응속도상수에 크게 영향을 받으며 약 70%의 반응 전화율에서 발생하여 단량체 농도와 개시제 농도가 각각 급격하게 감소 또는 증가함을 알 수 있었다. 또한 제시된 모델식을 사용하여 모사한 결과, 본 실험조건에서는 약 M/W 비가 약 0.5이하, 개시제 농도가 약 3 wt%, 그리고 냉각온도가 75℃이하에서 반응폭주의 발생을 억제할 수 있었다.
The present study analyzed the effect of operation condition on the runaway reaction at styrene suspension polymerization and proposed how to determine the operation condition. In the experiment for this study, the reaction temperature with time was measured in varying the ratio of the monomer(styre...
The present study analyzed the effect of operation condition on the runaway reaction at styrene suspension polymerization and proposed how to determine the operation condition. In the experiment for this study, the reaction temperature with time was measured in varying the ratio of the monomer(styrene, M) to the dispersion medium(water, W), the concentration of the initiator(BPO), and the monormer mass which was 1∼3, 1∼3 wt%, and 125∼165 g, respectively. In addition, the maximum exothermic temperature, the maximum exothermic time, and the maximum exothermic rate were estimated from the reaction temperature curve. According to the experimental results, the maximum exothermic time was delayed with decreasing the ratio of M to W for the constant monomer mass because of the excellent thermal stability of water, while the maximum exothermic temperature and the maximum exothermic rate were decreased. As the concentration of the initiator was increased, the maximum exothermic time was decreased. However, the maximum exothermic temperature and the maximum exothermic rate were increased, which implies the increase in the runaway reaction. In addition, the exothermic initiation time was decreased to some degree with increasing the monomer mass at the constant the ratio of M to W and the concentration of the initiator, while the maximum exothermic rate was not changed significantly. While the theoretical value that was estimated from the equations of the mass and the energy balances based on the kinetic model of the free radical polymerization was varied from the experimental value to some extent for the maximum exothermic temperature, it was almost consistent with the experimental value for the time of the exothermic initiation. The runaway reaction was significantly affected by the reaction rate constant of the propagation which was similar to the temperature curve. The phenomena of the runaway reaction occurred at 70% reaction conversion. At the moment of the occurrence, the concentration of the monomer was rapidly decreased, while the concentration of the initiator was rapidly increased. The result of computer simulation using equations of the mass and the energy balances in this experiment showed that the runaway reaction did not occur under the condition of 0.5 below for the ratio of M to W, approximate 3 wt% for the ratio of I to M, and below 75˚C for the cooling temperature.
The present study analyzed the effect of operation condition on the runaway reaction at styrene suspension polymerization and proposed how to determine the operation condition. In the experiment for this study, the reaction temperature with time was measured in varying the ratio of the monomer(styrene, M) to the dispersion medium(water, W), the concentration of the initiator(BPO), and the monormer mass which was 1∼3, 1∼3 wt%, and 125∼165 g, respectively. In addition, the maximum exothermic temperature, the maximum exothermic time, and the maximum exothermic rate were estimated from the reaction temperature curve. According to the experimental results, the maximum exothermic time was delayed with decreasing the ratio of M to W for the constant monomer mass because of the excellent thermal stability of water, while the maximum exothermic temperature and the maximum exothermic rate were decreased. As the concentration of the initiator was increased, the maximum exothermic time was decreased. However, the maximum exothermic temperature and the maximum exothermic rate were increased, which implies the increase in the runaway reaction. In addition, the exothermic initiation time was decreased to some degree with increasing the monomer mass at the constant the ratio of M to W and the concentration of the initiator, while the maximum exothermic rate was not changed significantly. While the theoretical value that was estimated from the equations of the mass and the energy balances based on the kinetic model of the free radical polymerization was varied from the experimental value to some extent for the maximum exothermic temperature, it was almost consistent with the experimental value for the time of the exothermic initiation. The runaway reaction was significantly affected by the reaction rate constant of the propagation which was similar to the temperature curve. The phenomena of the runaway reaction occurred at 70% reaction conversion. At the moment of the occurrence, the concentration of the monomer was rapidly decreased, while the concentration of the initiator was rapidly increased. The result of computer simulation using equations of the mass and the energy balances in this experiment showed that the runaway reaction did not occur under the condition of 0.5 below for the ratio of M to W, approximate 3 wt% for the ratio of I to M, and below 75˚C for the cooling temperature.
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