System analysis of the ethylbenzene dehydrogenation reactor as a control object

Abstract

Catalytic dehydrogenation of ethylbenzene charge in a two-stage continuous-action adiabatic reactor is the main stage of the styrene production process. The analysis of this technological process existing automated control systems revealed the following main drawback, that these systems require great efforts from production personnel to ensure a change of the reactor temperature regime in the stages of the reactor in accordance with styrene concentration drop, which is caused by deactivation catalytic layer deactivation. Therefore, the synthesis of the target product concentration at the reactor outlet predictive control system is actual task in the field of technical cybernetics. This article presents the system analysis results of the dehydrogenation reactor as a control object. The main research result is a method choice for controlling of the chemical transformations temperature regime in the reactor, using that, it is possible to increase the energy efficiency and productivity of this device. The general and specific tasks of the control system synthesis are formulated on the basis of the system analysis, the information and functional synthesis of the temperature regime ACS is produced, the information and functional schemes of the reactor unit process equipment control subsystems are developed. As an operating system ACS is selected, which realizes of steam-ethylbenzene mixture temperature change at the reaction zones entrances of the 1st and 2nd reactor sections in accordance with the program control algorithm on the basis of predicting models, describing the heat exchange processes occurring inside the reactor stages as well as the dynamics of changes in such parameters as the concentration of coke deposits, catalyst activity, the basic and by- products concentration of chemical reactions.