Simulação de temperatura e pressão máximas para análise de risco em reações de polimerização

Abstract

The production of chemicals involves handling hazardous products, thus requiring the adoption of prevention and control measures to reduce the risk of accidents with workers, the public and the environment. In this context, the role of the chemical engineer is to identify these risks and minimize them in line with the economic limitations of the process. Risk can be defined as the relationship between the consequence and the probability of an event. These events must be studied even before they happen, in order to avoid their consequences, through the risk analysis of the process. The most used method for risk analysis is HAZOP, which aims to identify and reduce risks. This method consists of combining guide words with parameters in each part of the process, obtaining risks and identifying existing constraints. If the restraints are not enough, actions must be taken to reduce the risks. In the risk analysis of polymerization reactions, the exothermic character and the possibility of loss of control should be taken into account in case of any deviation in the process, and measures should be taken to avoid this. The most consequential scenarios were the increase in feed flow, the lack of reactor cooling and the increase in monomer concentration. To reduce risks, actions were taken, such as automating the feed flow, temperature control and monomer dosage. Simulations were performed to study these scenarios and evaluate the restraints and actions taken. A deviation of four times the supply flow could lead to a temperature of 138°C and pressure of 3.43 bar with bursting of the rupture disk to relieve the pressure. Failure to cool the reactor would lead to the most critical scenario with the temperature reaching 164°C and the pressure reaching almost 7.0 bar with the possibility of the reactor exploding. Increasing monomer concentration can lead to maximum temperature and pressure of 131°C and 2.75 bar, respectively. Finally, these results confirm the high severity of the scenarios and justify the existing containments and actions taken to control the polymerization reactions.