Temperature diagrams for preventing decomposition or side reactions in liquid–liquid semibatch reactors

Temperature oscillation in a catalytic particle of Fischer–Tropsch synthesis

“…Example of stable initial distributions with almost monotonic degeneration of disturbances present in Figs. [15][16][17]. Agreement between distributions of temperature and synthesis gas concentrations obtained by two principally different methods is quite reasonable (see Fig.…”

“…9, that simple approximation for stationary temperature distribution, obtained without mass transfer effects G p FT G 1 FT ¼ 1 reasonable agrees with data of numerical experiment carried by direct integration of Eqs. (15) and (16). Fig.…”

“…Temperature distribution along a particle radius calculated without mass transfer effects. Solid lines are numerical integration equations (15) and (16). Dashed lines are approximations (38a) and (39).…”

“…Note that no single algorithm exists for constructing Lyapunov functions, and heuristic reasoning is used in the case of each concrete problem for estimating the criterion of stability. In the case of well-studied chemical kinetics and adequate mathematical model of processes of heat and mass transfer, the processing of the results of numerical simulation may be used for identifying ranges of parameters which provide for the stability of reactor operation (see, for example [15][16][17]). …”

Emulsion polymerization of vinyl acetate: Safe optimization of a hazardous complex process

“…Polymerizations are known to be one of the most frequent causes of thermal runaway (that is, loss of the reactor temperature control occurring whenever the rate of heat removal through the cooling system becomes lower than the rate at which the heat is evolved by the synthesis reactions) in fine chemical industries [1,2] because of three main aspects: (1) the high exothermicity involved [3] (up to 110 [kJ/mol]); (2) the hazard of free radical accumulation that causes sudden propagation reaction rate acceleration (Trommsdorff or gel effect [4,5]); (3) under atmospheric pressure, the occurrence of boiling phenomena followed by stable foam formation above a threshold temperature (in the following referred to as MAT, "Maximum Allowable Temperature" [6]). For all these reasons, a safe optimization of such processes (namely, the search for a dosing time able to maximize both safety and productivity), at both laboratory and industrial scale, is difficult to perform.…”