TFE裂解工艺F22汽化节点非稳态本质安全分析

Process safety analysis is important and necessary in the chemical process industries. However, a lack of a systemic methodology for inherent safety studies in an unsteady state, which causes more hazards and accidents. In order to analyze the inherent safety of the F22 vaporization unsteady state process of the steam dilution pyrolysis, the lumped parameter mathematic model for the F22 vaporization was established by using the thermal equilibrium equation. The model was numerically calculated to obtain the unsteady state time course profiles of operating temperature, pressure and F22 gas outlet mass flow rate, which were consistent with the field data. Then, the factors influencing the inherent safety of the TFE production process were systematically analyzed. The inherent safety index system of the TFE production process was established from three aspects of chemical, process, and equipment. The indices were graded according to relevant standards,and literature and membership functions were established. Index values and calculated data were input into the MATLAB Fuzzy logic toolbox. The IF-THEN rules were used to establish the Fuzzy inference rules, and the inherent safety degree of each index was defuzzified by the method of center of area (COA). The initial weight and variable weight of each index were calculated using the combination of analytic hierarchy process and variable weight method. Finally, the inherent safety degree of the F22 vaporization node was calculated. The results showed that the steady state time is nearly 1 000 s. The temperature, pressure, and outlet gas volume in the first 500 s increase rapidly. The steady state values are 268.55 K、432.405 kPa and 1.085 kg/s respectively. The inherent safety degree decreases with time. The initially inherent safety 0.576 4 dropped to 0.574 2 at steady state. The results showed that the unsteady state (a start-up process) appears a higher risk. The method and results provide a theoretical basis for the safe design, monitoring, and management of the F22 vaporization node in the process.