This paper describes the scheme that has been developed for the optimal control of the process of pyrolysis for different types of hydrocarbon feedstock in the four-flow pyrolysis furnace at the Sumgait Ethylene-Polyethylene plant; the scheme is based on the use of a complex parameter of the process, i.e., the pyrolysis intensity function. The algorithm for this control has been constructed. In the paper, the results of optimal control of the process of propane pyrolysis, ethane pyrolysis, and pyrolysis of ethane together with the butane-butylene fraction are presented in accordance with the scheme being developed using the intensity function that corresponds to each process. Optimal values of the intensity function were found from the results of calculations carried out using the mathematical model of each process. The extended expression for the intensity function has been formulated and, with its use, it is possible to control the process both in the case of the change in the flows of feedstock and steam and the change in the inlet temperature, as well as in the case of the change in the feedstock composition.
Представлена разработанная схема оптимального управления процессом пиролиза разных видов углеводородного сырья в четырехпоточной пиролизной печи сумгаитского завода “ЭтиленПолиэтилен”, основанная на использовании комплексного параметра процесса функции жесткости. Составлен алгоритм этого управления. Представлены результаты оптимального управления процессом пиролиза пропана, этана и этана совместно с бутан-бутиленовой фракцией по разработанной схеме с помощью соответствующей каждому процессу функции жесткости. Оптимальные значения функции жесткости находились на основании результатов расчетов, проведенных по математической модели каждого процесса. Составлено обобщенное выражение функции жесткости, с помощью которого возможно управлять процессом как в случае изменения расходов сырья, пара и входной температуры, так и при изменении состава сырья.
A mathematical model of hydrate formation in the Freon R-142B-water system was developed; the problem of process optimization was solved using the throughput of the reactor with respect to gas hydrate as a criterion. The maximum throughput of the reactor, with respect to gas hydrate of 1086 kg/(m3 h), was found to be attained at a temperature of 8°C and pressure of 0.9 atm at the specified charge of 10 m3/h.
Разработана математическая модель процесса гидратообразования в системе фреон R-142Bвода, и решена задача оптимизации процесса с применением в качестве критерия производительности реактора по газовому гидрату. Установлено, что при заданной загрузке 10 м3/ч максимальная производительность реактора по газовому гидрату 1086 кг/(м3 ч) достигается при температуре 8°С и давлении 0.9 атм.
A mathematical model of oligomerization of propane–propylene cut with consideration of deactivation of the catalyst was developed. The optimum process parameters that allow obtaining the components of different brands of oil were determined. A kinetic model of hydrogenation of oligomers was formulated for production of white oils.
A general technique was developed for optimal designing pyrolysis with feedback of hydrocarbons C2-C4 and their mixtures. Based on this technique, we carried out a study of industrial processes of pyrolysis of propane, ethane, and ethane with the butane-butylene fraction, developed their complete mathematical models that reflected the peculiarities of recycling, and on the basis thereof we defined optimal regimes of governing by these processes that differed significantly from those used in industry. We suggested new ways of governing by all three processes. The use of these ways will allow getting a significant profit by “Ethylene-Polyethylene” plant (Sumgayit). We demonstrated advantages of carrying out pyrolysis of various raw materials with recycling of unreacted raw materials compared with its conducting without recycling.
The calculated results from the mathematical simulation of an industrial ethane pyrolysis process carried out at the Ethylene-Polyethylene Works in Sumgait under the average constant thermal stress of radiant coil were compared with the results calculated for the same process but using the suggested method of zoned fuel gas supply. The derived mathematical description of the industrial feedback process is given. The optimum thermal stress values calculated from the mathematical model for each zone were used to calculate the optimum fuel gas supplies to each zone, providing the maximum yields of the target products. The results of the comparison of the suggested method of conducting the process with that accepted in industry are evidence of the advantages of the fuel gas supply by the coil zones. This essentially saves fuel gas and provides a higher yield of the target products and results in a higher profit for the company. An expression is given to calculate the optimum fuel gas supply to each zone, even under variable reactor inlet conditions (loading and inlet temperature), which allows for the effective control of the process.
Based on experimental kinetic data for the reductive amination of monoethanolamine in the presence of the NiCo/BPO4 · γ-Al2O3 catalyst, a mechanism of this process is suggested and the corresponding kinetic model is constructed. A mathematical model of the reactor process is developed, and this model is used to solve three process optimization problems. Optimal values of operating parameters are found, and these values are used in the calculation of basic dimensions of a commercial-scale reactor. The flexible process design suggested allows all of the three process variants corresponding to the three optimization problems to be carried out.
The kinetic mechanisms of hydrogenation of propane-propylene fraction oligomers on a platinum-containing catalyst were investigated at different temperatures and pressures. The kinetic model developed adequately describes the experimental data.
A two–stage optimal design procedure is suggested for alkane pyrolysis processes and is applied to propane pyrolysis. The first stage considers only hydrocarbon decomposition, the primary reaction in the process. A mathematical model consisting of an overall stoichiometric, an empirical rate, and a heat–balance and hydrodynamic equation is constructed. This model is analyzed for a varied tube diameter and a fixed propane conversion to optimize the design parameters of the propane pyrolysis reactor. At the second stage, the main reaction is considered together with secondary and tertiary reactions and a complete model taking into account recycling of the unreacted raw material is constructed. The optimum inlet temperature and recycle ratio are determined as a function of the total feed rate. An economic optimality criterion is suggested, and final process optimization is carried out.
