Effect of process variables on the exothermicity during the production of phenol–formaldehyde resins – modeling by response surface methodology

Different types and grades of phenolic resins are produced under a wide range of operating conditions in the resin producing industries. Different operating conditions employed for the production of such resins result in the evolution of different quantities of exothermic heat. A fuzzy logic control method was employed to control the exothermicity of the above reaction and was found to control the reaction efficiently and to maintain the temperature at any predetermined target value. The control system was also found to function as a suitable reaction calorimeter in which the commercial reaction between phenol and formaldehyde under alkaline conditions can be simulated and the exothermic behavior studied under different industrially used operating conditions. In order to understand the system’s behavior, mathematical relationships between the process variables and the exothermic behavior were established by employing the ‘Response surface methodology’. Geometrical representation of the mathematical models in three-dimensional surface plots served as a good aid in understanding the behavior of the reaction under different operating conditions. These results are reported in this paper.