Optimization of the Reactive Flash System Kinetics for Steel Pickling Liquid Recycling
| Autor: | Chou, Shang-Hung, 周尚宏 |
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| Rok vydání: | 2016 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 104 Pickling is a necessary process in Metallurgical and Metal Surface Treatment Industries for removing metal surface oxide and other pollutants in order to facilitate processing quality. Hydrochloric acid has been used mostly in picking liquid processes, during this process the acid concentration will decrease and metal (iron and zinc) ion concentration will increase with time; when the residual concentration of hydrochloric acid in pickling liquid solution reduces to about 3%, or acid liquid specific gravity is greater than 1.3 (iron ion concentration greater than 100g /L), the aging acid liquid should be discharged and replaced with a new hydrochloric acid solution. Ferrous chloride is contained in spent pick acid. The objective of this research is to reclaim the spent pick liquid through chemical reactions. Domestic wire rod industries have produced highly corrosive spent pick acid due to pickling processes, although the development of process technologies, so far, offers a variety of treatment techniques resources, including spray roasting, fluidized bed calcination and sulfuric acid addition technology, but it is hindered by considering the processing capacity, preliminary design cost, operating costs, selling prices and purity of subsequent regeneration product and size of the market and many other limiting factors. In this study, we refer to the experimental data in the literature for sulfuric acid addition technology and utilize Simulated Annealing algorithm to optimize the kinetic parameters, which using minimum variance regression by simulating the amount in moles of each substance in the container and the reclamation of hydrochloric acid, which are varying with time. The optimization analysis of this study is divided into two stages. At the first stage, a simple batch reaction model is assumed to estimate the preliminary values of kinetic reaction rate parameters for the second stage. Firstly, Microsoft Office Excel 2013 Chart tools is implemented to produce trend line equation model for the concentration data through time; then the simulated annealing optimization method is utilized to obtain the progression parameters, m and n, of FeCl2 and H2SO4 concentration respectively in the reaction rate formulation, and subsequently to solve the activation energy (Ea) and Arrhenius constant (A) in the Arrhenius equations for 80 ℃ and 85 ℃. At the second stage, a reactive flash three-phase system model has been developed; the kinetic parameters (Ea, A, m, n) are optimized by using simulated annealing algorithm and the range or the upper and lower bounds of the four optimized parameters is based on the values obtained at the first stage. This system thermodynamic model is based on ideal gas and liquid, assuming gas fugacity and liquid activity coefficients are equal to 1, the results show that optimal values of the parameters Ea, A, m, n are respectively: -846080.7, 2.4939E-19, 0.48719, 1.9493 in NRTL enthalpy systems, and -838740, 2.49394E-19, 1.1243, 1.94929 in Electrolyte NRTL (ELECNRTL) enthalpy systems derived from Aspen Plus 8.8. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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