Modeling and optimization of reaction furnace and waste heat boiler of Claus process

The aim of this thesis is to model the thermal section of the Claus Process as a configuration of two reactors, which are reaction furnace and waste heat boiler (WHB), and then optimize the whole section. In the thesis study, two different reduced kinetic schemes were provided for reaction furnace and WHB and validated with the detailed kinetic model on DSMOKE program. Using the validated kinetics, the mathematical models were developed for both units. The waste heat boiler was modeled as a plug flow reactor with heat transfer, instead of a heat exchanger, and the models were simulated in the MATLAB environment. The simulation results were compared with the literature and the models were verified, and then optimization studies were carried out. The temperature of the feed gas mixture, the air molar flow rate, the fuel molar flow rate, and the acidic gas molar flow rate at the inlet of the reaction furnace were chosen as decision variables. Maximizing the amount of elemental sulfur at the end of the thermal section was the main objective, in addition, maximizing the amount of the steam generated in the WHB was considered as a secondary objective, and the multi-objective optimization problem was solved. Optimization studies were performed in MATLAB environment and optimum values for decision variables and objective function results were obtained by using fmincon, ga, particleswarm and gamultiobj solvers nested in the software. In addition, as an alternative, the Taguchi method, which is a method of design of experiment, was also used for optimization studies, analyzes of variance were carried out using Minitab program and optimum values were determined. As a result of the optimization studies, it was determined that the amount of both elemental sulfur at the WHB outlet and the steam produced at the WHB were increased.