Technological objects and processes are often characterized by fuzzy initial information necessary for developing their models and optimization. The purpose of the study is to develop a method for synthesizing linguistic models of fuzzy described objects and a heuristic method for solving the multicriteria optimization problem in a fuzzy environment. Based on the expert assessments and logical rules of conditional inference, a method for synthesizing linguistic models was developed for describing processes with fuzzy input and output parameters. To solve the problem of multicriteria optimization, a heuristic method based on the modification and combination of various optimality principles is proposed. Coking reactor models were developed by modifying the successive regression inclusion method and the least squares method. Linguistic models of the delayed coking process were developed in the Fuzzy Logic Toolbox, allowing to evaluate the coke quality depending on the temperature and pressure of coking reactors. Using the proposed heuristic method, the problem of two-criteria optimization of the delayed coking process with fuzzy constraints is solved. The results confirm the advantages of the proposed fuzzy approach compared with the well-known approaches. Unlike them, the proposed method allows making adequate decisions in a fuzzy environment by maximizing the use of available fuzzy information.

The purpose of this study is to develop a method for synthesizing mathematical models of interconnected units of fuzzy chemical-technological systems (CTS) used for system modeling and optimization of their operating modes in a fuzzy environment. Since many CTSs in practice consist of many interconnected units, the development of their mathematical models combined into a single system of models, which allows systematic modeling and optimization of CTS parameters, is an urgent scientific and practical task. To develop a system of models of fuzzy described CTS, consisting of interconnected units, a system of methods is used that combines formal (experimental-statistical) and informal methods (methods of peer review, fuzzy set theory). A method for developing a system of mathematical models of CTS units under conditions of uncertainty due to the random and fuzzy nature of the available information is proposed. In the proposed method, mathematical models of various CTS units, depending on the nature of the initial and available information, are developed by various methods. Accordingly, various types of models are obtained, which are then combined into a single system of models, taking into account the interconnections of the system’s units. These results make it possible to develop more adequate models and determine the optimal CTS operating modes in a fuzzy environment by using the experience, knowledge and intuition of the decision maker, subject matter experts. Based on the proposed method, models of coke chambers and the main rectification column are developed in the form of combined models, including statistical and fuzzy models. The results obtained on the example of delayed coking units can be exported to similar CTS in oil refining, petrochemicals and other industries.

The paper studies the problems of developing fuzzy and linguistic models of poorly formalized production facilities using available fuzzy information and other types of data. Since known methods do not allow us to effectively solve these problems in a fuzzy environment, we propose a systematic method and a heuristic approach to decision making for the effective objects control in a fuzzy environment. The proposed system method makes it possible to develop fuzzy, linguistic models of complex objects, and a heuristic approach to the formulation and solution of the adoption problem - to adequately and effectively solve the problem of fuzzy described objects control. In the proposed heuristic method of fuzzy decision making, effective control of the coking process is ensured through the maximum and effective use of fuzzy information representing the experience, knowledge and intuition of the decision maker, experts. Using the proposed system method, fuzzy and linguistic models of the studied coking reactors of the delayed coking unit of the Atyrau refinery were developed. A computer modeling system has been created that allows, as a result of modeling, to select the optimal operating modes of coking reactors. Based on the developed models using the proposed heuristic decision-making method, modifying and combining the principles of maximin and Pareto optimality, the problem of effective control of the delayed coking process was successfully solved. Comparison of the obtained results with the results of known methods and real data shows the advantages, efficiency and high adequacy of the proposed methods in a fuzzy environment. The practical significance of the results obtained is that they can be adapted and successfully applied in modeling and decision making for the effective complex objects control in a fuzzy environment.