Abstract:

A mathematical model of the countercurrent benzene extraction stage of the spent acid of nitrobenzene production in a steady-state mode was developed. Processes of benzene nitration with nitric acid radicals contained in the spent acid and the transition of nitrobenzene to the organic phase occur during extraction. In the model, the optimal process organization - a two-stage extraction - separation in a countercurrent circuit was revealed. Decomposition of the research object into "nitration" and "extraction" subsystems was carried out, development of models of subsystems in the form of systems of nonlinear algebraic equations of stationary processes of nitration and extraction was conducted, their analysis was performed. Based on the analysis, the optimal process organization - a two-stage extraction - separation in a countercurrent circuit was revealed. The synthesis of the combined model in the form of a system of nonlinear equations describing stationary processes of both nitration and extraction was held. In the model, the effect of input parameters was investigated. It was found that the separation efficiency is strongly influenced by the temperature and the concentration of sulfuric acid in the spent acid and weakly - by the benzene: spent acid ratio. The tabular dependence of the residence time in the system to achieve acceptable residual nitric acid concentration at the outlet (0.05%) on the temperature, concentration of sulfuric and nitric acids in the spent acid was built. Based on this dependence, a process mode was proposed. The results can be used in the design of industrial nitration schemes and improvement of the nitrobenzene production technology. Author Biographies Сергей Алексеевич Кондратов, Institute of Chemical Technology, Volodymyr Dahl’s East Ukrainian National University, Lenina street 31, Rubezhnoye, Luhans'ka oblast, 93010 Dr. Sc. (Chemistry), Professor, Head of the department Department of mathematics and computer technologies  

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