A Study of Method for Estimating Induction Time until Polymerization Runaway of Polymerization Monomer

Generally, when a polymerizable monomer is stored in a tank, a polymerization inhibitor is added to suppress the polymerization reaction, but in the unlikely case that the contained polymerization inhibitor is consumed, the temperature of the tank rises due to the polymerization reaction, which leads to a polymerization reaction, In the worst case, this can lead to serious accidents. Therefore, in the plant, thermometers are installed in the tank to monitor the temperature of the polymerizable monomer, and if the temperature of the polymerizable monomer rise, the polymerization inhibitor is added to the tank as an emergency response to suppress polymerization runaway. To prepare for emergency response like this, it is important to know in advance the period from the temperature rise to the polymerization runaway, it called induction period. Originally, it is preferable to do storage test on all the polymerizable monomers handled in the plant and measure the induction period. However, it is known that the induction time changes depending on the kind of polymerizable monomer and the kind and the concentration of polymerization inhibitor contained, so it is not realistic to do storage test on all samples because it too much time. Therefore, it is necessary to construct a method for estimating the induction period in a short period of time.

In this Study, we constructed a method to estimate the induction period in a short time. we measured the exothermic behavior of the polymerized monomer after consuming the polymerization inhibitor using Acceleration Rate Calorimeter and Calvet Calorimeter, and based on this data, estimated the state of Polymerization reaction in the low temperature range close to the storage temperature. As a result, the method makes it possible to grasp the time available for emergency response in a short period of time and to install appropriate emergency response equipment to each tank of polymerizable monomer.