Multi-criteria optimisation problems for chemical engineering systems and algorithms for their solution based on fuzzy mathematical methods

Mathematical equations for the multi-criteria task of the optimisation of chemical engineering systems, for example for the optimisation of working regimes for industrial installations for benzene production, have been formulated and developed, and based on fuzzy mathematical methods, algorithms for their solution have been developed. Since the chemical engineering system, which is being researched, is characterised by multiple criteria and often functions in conditions of uncertainty, the presenting problem is formulated in the form of multicriteria equations for fuzzy mathematical programming. New mathematical formulations for the problems being solved in a fuzzy environment and heuristic algorithms for their solution have been developed by the modification of various optimisation principles based on fuzzy mathematical methods

Systematic Approach to the Elaboration of a Structured Model of a Sulfur Production Unit under Uncertainty

The paper proposes a systematic approach to the elaboration of a structured mathematical model and modeling of chemical and technological systems under uncertainty exemplified by a sulfur production unit. The novelty of the suggested method lies in the choice of a suitable model type for each element of the system based on the systematic analysis, development of the selected model type and their merger into a unified system of models. The method was successfully implemented to construct a system of models for major units of the catalytic reforming plant at the Atyrau Oil Refinery (Republic of Kazakhstan). The study compares existing results, modeling results based on the suggested method and experimental results obtained using an LG-setup of the Atyrau Oil Refinery. The deliverables demonstrate high efficacy and excellence of the approach to the modeling of interconnected equipment (chemical and technological systems)

Development of Mathematical Models and Modelling of Chemical Technological Systems using Fuzzy-Output Systems

The paper proposes a systematic approach to the development of structured mathematical model and modelling of Chemical-Technological Systems (CTSs) of refinery under fuzzy conditions. Idea and novelty of the proposed method are based on the study of each unit of chemical-technological systems, and based on obtained results, the model of separate element of chemical-technological systems unit is designed. At the next stage, separately-developed models are combined into a single system to fully model the process. The developed method has been successfully implemented during the construction of models system of the basic reforming units of catalytic reforming at Atyrau oil refinery. Comparison of the known results and modelling results based on the proposed method demonstrates the effective realization for constructing a system of models for main units of sulfur production in Atyrau oil refinery

Methods of Constructing Models and Optimizing the Operating Modes of A Chemical Engineering System for the Production of Benzene in A Fuzzy Environment

The study object: the chemical engineering system for production of benzene and optimization of the system operation modes based on modeling. An approach to the effective solution of problems of optimization of operating modes of real chemical engineering systems was proposed. Since such systems are usually multicriterial and characterized by the fuzziness of initial information, an approach to the development of their models and optimization of their operating modes in a fuzzy environment was proposed. The essence of this approach lies in the construction of mathematical models and optimization of system operation modes based on the system analysis methodology using available information of deterministic, statistical, and fuzzy nature. Statements of the problems of optimization by means of chemical engineering systems in a fuzzy environment have been obtained by modifying various principles of optimality for working in a fuzzy environment. Based on a modification of the principles of maximin and Pareto optimality, a heuristic algorithm for solving the formulated optimization problem was proposed based on the use of knowledge and experience of decision-makers. The proposed method of model construction and an optimization algorithm were implemented in practice when constructing models of benzene and rectification columns of a chemical engineering system of production of benzene when formulating and solving the problem of optimizing their operation modes in a fuzzy environment. Analysis and comparison of optimization results allow us to conclude about the effectiveness of the proposed fuzzy approach to solving optimization problems in a fuzzy environment. As a result of optimization of the benzene production process, the benzene yield increased by 1.45 thousand t or by 1.1 %, the raffinate output volume increased by 0.4 thousand t in conditions of upholding constraints on benzene quality. The proposed approach makes it possible to assess the degree of upholding of fuzzy constraint