Josef Horák

Experimental study of the behaviour of an isothermal continuous stirred tank reactor in the course of an autocatalytic reaction

Abstract The dynamic behaviour of an isothermal continuous stirred tank reactor and of a two-element series of continuous stirred tank reactors in the course of an autocatalytic reaction of bistrichlormethyl-trisulphide with aniline, in methanol at 20°C, was studied. It was shown that the regime of the continuous stirred tank reactor and of the series is unstable ia a certain region of the conversion of the initial reaction component (bis-trichlormethyl-trisulphide) and that in a certain interval of the reaction mixture feed rate the reactor can operate at a single value of the feed rate in two (the series in three) stable states. The values of the bis-trichlormethyl-trisulphide conversion in steady states, as well as the dependence of the conversion on the period of stabilization of the reactor regime, determined experimentally in a continuous stirred tank reactor and in the series are in good agreement with the values computed from the kinetic data, determined in a discontinuous stirred tank reactor.

A simple principle of reaction calorimetry

Abstract A new measuring principle for following a rate of heat evolution in exothermic reactions under isothermal conditions has been proposed and experimentally tested. The reaction is carried but in an insulated vessel equipped with a cooling coil. The reaction heat is removed by stepwise addition of a coolant into the cooling coil. Using the oxidation of ethenol by hydrogen peroxide catalyzed by ferric ions as a model reaction, practically the same precision in estimation of rate data has been achieved with this thermokinetic method as with the chemical analysis of reaction mixture.

Modelling of Steam Cracking. I. Simplified Mathematical Model of Steam Cracking Furnace and Its Identification

A simplified mathematical model of a steam cracking furnace was constructed. The model involves adjustable parameters, values of which are to be evaluated on the basis of measurements available in industrial reactors. The following adjustable parameters are considered: the effective radiative heat transfer coefficient, the convective heat transfer coefficient, the mean relative reactivity of the reaction mixture. The sources of information which can be utilized in the model identification are discussed. A numerical procedure was developed for finding the best set of the adjustable parameters. The procedure is based on the analogy with single-input single-output control loops.

Unisothermal Control of the Cascade of CSTR Using Constant Degree of Thermal Stability

Unisothermal control of a cascade of continuous stirred tank reactors was analyzed. The control strategy is based on keeping the same degree of the thermal stability for all reactors in the cascade. The cooling driving force (the stationary temperature difference between the reaction mixture and the coolant) was used as the measure of the thermal regime stability. The structure of possible steady states was established, the thermal stability and technological properties of steady states were discussed. The most advantageous set of stationary states is recommended and the possibility of practical application of the suggested control strategy was discussed.

The Mathematical Model of Naphtha Steam Cracking

The mathematical model of naphtha steam cracking has been developed to predict products yields. The feedstock composition, feedstock rate, steam-oil ration, inlet temperature, outlet temperature and outlet pressure are introduced as inputs. The reaction model consists of two parts: the radical reactions of higher alkanes, higher alkenes, naphthenes and alkylaromatics and the formal molecular reactions of lower alkanes and lower alkenes. The model was identified using a series of large-scale experiments including four naphtha raw materials. Eight experiments were carried out for each naphtha kind at two levels of the temperature profile, feed rate and steam-oil ratio.

Millisecond pyrolysis ― mathematic model and parametric sensitivity

Ethane-water vapour pyrolysis and the influence of the system parameters on the pyrolysis furnace behaviour were studied using mathematical model describing the reactor constructed from Fields pipes. The parameters under discussion are following: reaction mixture feed rate, inlet pressure, heat transfer temperature (furnace temperature), addition of overheated water vapour, thickness of coke layer on the reactor walls and radiation heat transfer inside the reactor

Analysis of the oscillatory behaviour of an industrial reactor for the oxonation of propene. Evaluation of flow models based on the response to a pulse signal

The response of an industrial reactor for the oxonation of propene to its spiking with a radioactive tracer was compared with simulated responses obtained for models of various structures, viz. a cascade of two perfectly stirred cells of different size, a cascade of two perfectly stirred cells of the same size with recirculation of the reaction mixture, a cascade of two perfectly stirred cells of the same size with inflow into both cells, and a system of two perfectly stirred cells with back-flow involving a plug-flow element. None of the flow models fitted the experiment perfectly; the best fit was obtained for the combination of perfectly stirred cells and back-flow with a plug-flow element.