Kinetics study and thermal hazard analysis for phenol-formaldehyde polymerization reactions in batch processes

• Main Authors: Lu Kai-Tai, 陸開泰
• Other Authors: Hu Kwan-Hua
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/29295481085748709076

博士 === 中正理工學院 === 應用化學學系研究所 === 86 === The polymerization of phenol-formaldehyde is rather important and complicated productive procedure in the chemical industry. Its exothermic polymeric process can release a huge amount of heat in reaction. This high reaction temperature can lead to the process to a runaway reaction hazard situation owing to the improper temperature management. In this investigation, we use NaOH as alkali-catalyst in polymerization. Various formaldehyde/ phenol ratios ([F]/[P]) were chosen as 1,2, and 3 at three pH values, i.e., 8,9, and 10 in our experiments. In the preliminary study, we use DSC (Differential Scanning Calorimetry) to measure reaction heat of overall exothermic polymerization. Which helps use to understand the thermal hazard runaway reaction in this process. Then, we use HPLC (High Performance Liquid Chromatograph) to estimate the rate constants and activation energy at each step reaction for various monomer reactions. Further more, the RSST (Reaction System Screening Tool) and VSP2 (Vent Sizing Package 2) were used to verify the values of reaction kinetic in monomer''s prepolymeric and polymeric reaction. From the various experimental conditions, the critical reliable condition before runaway reaction can be evaluated. Then, we can design a safety relief valve for the phenol-formaldehyde runaway reaction by means of the technique DIERS(Design Institute for Emergency Relief Systems). These results can increase the safety in process of factory manufacture. Finally, we apply Semenov*s thermal explosion theory to investigate the criticality of thermal explosion and its stable criterion of temperature in an exothermic reaction. These theorems can be used for a storage tank or reactor design in safety operation.