Ilchenko M. Substantiation of energy-efficient operation modes for the system of recuperative heat exchangers in the pyrocondensate processing

The research object is the heat exchange processes that occur in the recuperative heat exchanger network during the processing of pyrocondensate on installation of benzene production. The purpose of the work is to analyze the recuperative heat exchanger network and to identify its disadvantages in order to substantiate the energy-efficient modes of the plant operation and to further solving the problem of the energy efficiency increasing of pyrocondensate processing process. Methods of research: pinch-design method was used to determine the value of the external energy sources consumption in the chemical-technological processes and the amount of energy recovery; the principles of reduced costs dependencies constructing was used in the reconstruction of the heat exchange system; the method of network diagrams drawing was used to create a reconstruction project for the heat exchangers system; methods of mathematical modeling were used for detailed analysis of heat exchangers operating modes taking into account the phase state of heat-carrier; for calculations were used free mathematical packages, as well as computer programs for the installation of technological parameters of new plate heat exchangers required specification; "HILECT" software was used to calculate the value of the possible integration and energy and economic dependence curves construction; production modeling was carried out using of specialized software "UniSim Design". Theoretical and practical results: the system of recuperative heat exchange at the pyrocondensate processing plant was analyzed in order to identify its defects for further improvement by introducing the measures of technological streams integration and the substantiation of energy-efficient operating modes of a set of new heat-exchange equipment. Scientific novelty: processes integration methods, namely the pinch-analysis method, were further developed, which has allowed to confirm the high efficiency of such calculation-and-design means for designing of modern heat exchange networks involved into the pyrocondensate processing; the technologies of pinch-design and thermal integration into the active heat-exchange equipment network, involved in the pyrocondensate processing during the continuous production of benzene, were applied for the first time; the low efficiency of the elements of the existing heat exchange system experimentally revealed and some measures to increase a number of production indicators due to the network technical re-equipment by completing the combined heat transfer surface with a set of new plate heat exchangers with high production characteristics were proposed; the optimum value of the minimum temperature pressure, the amount of available heat energy recovery and the amount of energy, required to be brought from the outside, were determined for the first time, that’s ensure the efficiency of the heat exchange system involved in the processing of pyrocondensate at the benzene production plant; the mechanism of processing and use of technological data to create simulation models of petrochemical and processing industries using the software UniSim Design, which allowed to verify the correctness of initial experimental data and to determine the missing thermal and physical characteristics of heat exchange streams were further developed; the variants of energy-efficient integration projects were developed for the first time under conditions of variant-optimization heat exchangers system designing in technological lines of some installation units. The degree of implementation: the results of the work were introduced into the educational process of the Department of Integrated Technologies, Processes and Apparatuses of the National Technical University "Kharkiv Polytechnic Institute". Scope of application: chemical, petrochemical, oil refining, energy and related industries.