Process Simulation and Control Optimization of a Blast Furnace Using Classical Thermodynamics Combined to a Direct Search Algorithm

Several numerical approaches have been proposed in the literature to simulate the behavior of modern blast furnaces: finite volume methods, data-mining models, heat and mass balance models, and classical thermodynamic simulations. Despite this, there is actually no efficient method for evaluating quickly optimal operating parameters of a blast furnace as a function of the iron ore composition, which takes into account all potential chemical reactions that could occur in the system. In the current study, we propose a global simulation strategy of a blast furnace, the 5-unit process simulation. It is based on classical thermodynamic calculations coupled to a direct search algorithm to optimize process parameters. These parameters include the minimum required metallurgical coke consumption as well as the optimal blast chemical composition and the total charge that simultaneously satisfy the overall heat and mass balances of the system. Moreover, a Gibbs free energy function for metallurgical coke is parameterized in the current study and used to fine-tune the simulation of the blast furnace. Optimal operating conditions and predicted output stream properties calculated by the proposed thermodynamic simulation strategy are compared with reference data found in the literature and have proven the validity and high precision of this simulation

ÉTUDE DE LA DISTRIBUTION SPATIALE DES OVOGONIES DANS L'OVAIRE D'EMBRYON DE RATTE A L'AIDE DE L'ANALYSEUR DE TEXTURES

International audienc

ÉTUDE DE LA DISTRIBUTION SPATIALE DES OVOGONIES DANS L'OVAIRE D'EMBRYON DE RATTE A L'AIDE DE L'ANALYSEUR DE TEXTURES

International audienc

Evaluate Sulfone-Based Reduction Sensitive Electrolytes with Lithium Li4Ti5O12/Li and Symmetric Li4+XTi5O12/Li4Ti5O12 Cells

International audienceBinary mixtures of cyclic or acyclic sulfones with EMC or DMC are used in electrolytes containing LiPF6 (1M) in both Li4Ti5O12/Li half-cells and Li4+xTi5O12/Li4Ti5O12 symmetrical cells and compared with standard EC/EMC or EC/DMC mixtures. In half-cells, sulfone-based electrolytes cannot be satisfactorily cycled owing to the formation of a resistive layer at the lithium interface, which is not stable and generates species (RSO2-, RSO3-) able to migrate toward the titanate electrode interface. Potentiostatic and galvanostatic tests in Li4Ti5O12/Li half-cells show that charge transfer resistance increases drastically when sulfones are used in the electrolyte composition. Moreover, cycling ability and coulombic efficiency are low. At the opposite, when symmetrical Li4+xTi5O12/Li4Ti5O12 cells are used, it is demonstrated that MIS- (methyl isopropyl sulfone) and TMS- (tetra methyl sulfone) based electrolytes exhibit reasonable electrochemical performances compared to the EC/DMC or EC/EMC standard mixtures. Surface analysis by XPS of both the Li4+xTi5O12 (partially oxidized) and Li7Ti5O12 (reduced) electrodes taken from symmetrical cells reveals that sulfones do not participate in the formation of surface layers. Alkylcarbonates (EMC or DMC), used as co-solvents in sulfone-based binary electrolytes, ensure the formation of surface layers at the titanate interfaces