Development of Volterra-Hybrid and Laguerre models for phenolic resin formation, resol-type, in batch reactors

Abstract

The phenolic resin formation process it can improve if phenol-formaldehyde reaction can be expressed by novel models in which its exothermicity, as well as its chemistry kinetics, is involve. For obtain such objective, the identification process is performed by using the formalisms, Volterra-Hybrid (VL) and Laguerre (LM), as proposed. Nevertheless, is noteworthy that this work is focused in identification the behavior of this reaction in resol-type resin synthesis, under conditions of molar excess and alkaline conditions in industrial batch reactors. In this study, all behavior patterns of the process are mathematically described. The process is started up by heating the reactants, up to reach 62°C in which is reached the activation energy, whereby is must stop the heating action due to manifesting exothermicity of the reaction. Then with this temperature within the reactor, the second stage starts up by applying water in the cooling jacket for smoothing the exothermicity degree, and minimize the risk at the system, in this stage the reactants should reach 102°C. Then the third phase is started up, such that the steam that not yet is part of the resin, it refluxes between a heat exchanger and the reactor. The goal of this activity is reach to compensate the exothermicity. Nevertheless this reflux action has an average duration of 45 min, and when reactor is cooled 101°C only the phenolic resin should be keep inside reactor, thereby the remainder of water must be excluded. Finally, around 100°C start the fourth phase, it which finishes when the reactor is cooling at the temperature of 50°C, and then all process is closed by adding around 1.5% of ethanol. The methodology applied has shown an acceptable fitting between model and data, which it means the model, presents important prospects as a tool to automate the exothermic batch reactors with strong challenges by using mathematical models, without the complexity of the chemical equations.