Iron corrosion in acidic media is a natural phenomenon that converts elemental iron to a more chemically-stable form,i.e.its oxide and hydroxide.In this study,the iron corrosion process is modeled as a completely impl...Iron corrosion in acidic media is a natural phenomenon that converts elemental iron to a more chemically-stable form,i.e.its oxide and hydroxide.In this study,the iron corrosion process is modeled as a completely implicit problem,solved by a novel finite difference model to provide insight into the ionic aspects of corrosion behavior.This new mathematical model eliminates the chemical potential parameters from the corrosion process equations,thereby reducing the need for experimental determination of chemical potentials.The eliminatedchemical-potential-parameters model predicts and quantifies key parameters(concentrations of conjugate base ion,iron(Ⅱ)ion,hydrogen ion,anodic and cathodic potentials,and the electrical current density)associated with the iron corrosion process in acidic solutions.The rigorous derivation and novel application of the eliminated-chemical-potential-parameters model and its results provide new insights into the iron corrosion process.The present model is also applicable in any industrial process which is associated with metal corrosion.The model helps to guide the design of future corrosion resistant systems,and various experimental studies pertaining to corrosion inhibition techniques.展开更多
Efficient tuning of the coefficients used by proportional-integral-derivative(PID)controllers enhances their performance.For highly non-linear systems,optimization algorithms are required to make the PID controllers m...Efficient tuning of the coefficients used by proportional-integral-derivative(PID)controllers enhances their performance.For highly non-linear systems,optimization algorithms are required to make the PID controllers more responsive to disturbances.The production of tert-amyl-methyl-ether(TAME),an essential additive for gasoline,in reactive distillation columns integrates highly non-linear reaction and separation processes.On the other hand,TAME distillation is an azeotrope distillation process,therefore non-linearity of this process is more complex than that of conventional distillation.PID-controller tuning methods applying a genetic algorithm(GA)and a particle swarm optimization(PSO)algorithm are compared using a dynamic simulation that integrates the optimization algorithms with the HYSYS process simulator.The PID controller response trends are analyzed following the introduction of a significant disturbance to the TAME reactive distillation column(i.e.,a ten percent change in the methanol feed temperature).The PSO PID controller tuning method that minimizes the integral of the absolute error(IAE)as its objective function significantly outperforms the GA tuning method.The novel PID-tuning methodology developed has more extensive application potential.展开更多
文摘Iron corrosion in acidic media is a natural phenomenon that converts elemental iron to a more chemically-stable form,i.e.its oxide and hydroxide.In this study,the iron corrosion process is modeled as a completely implicit problem,solved by a novel finite difference model to provide insight into the ionic aspects of corrosion behavior.This new mathematical model eliminates the chemical potential parameters from the corrosion process equations,thereby reducing the need for experimental determination of chemical potentials.The eliminatedchemical-potential-parameters model predicts and quantifies key parameters(concentrations of conjugate base ion,iron(Ⅱ)ion,hydrogen ion,anodic and cathodic potentials,and the electrical current density)associated with the iron corrosion process in acidic solutions.The rigorous derivation and novel application of the eliminated-chemical-potential-parameters model and its results provide new insights into the iron corrosion process.The present model is also applicable in any industrial process which is associated with metal corrosion.The model helps to guide the design of future corrosion resistant systems,and various experimental studies pertaining to corrosion inhibition techniques.
文摘Efficient tuning of the coefficients used by proportional-integral-derivative(PID)controllers enhances their performance.For highly non-linear systems,optimization algorithms are required to make the PID controllers more responsive to disturbances.The production of tert-amyl-methyl-ether(TAME),an essential additive for gasoline,in reactive distillation columns integrates highly non-linear reaction and separation processes.On the other hand,TAME distillation is an azeotrope distillation process,therefore non-linearity of this process is more complex than that of conventional distillation.PID-controller tuning methods applying a genetic algorithm(GA)and a particle swarm optimization(PSO)algorithm are compared using a dynamic simulation that integrates the optimization algorithms with the HYSYS process simulator.The PID controller response trends are analyzed following the introduction of a significant disturbance to the TAME reactive distillation column(i.e.,a ten percent change in the methanol feed temperature).The PSO PID controller tuning method that minimizes the integral of the absolute error(IAE)as its objective function significantly outperforms the GA tuning method.The novel PID-tuning methodology developed has more extensive application potential.
