Dynamic model for dehydration process of industrial purified terephthalic acid solvent is investigated to understand and characterize the process.A temperature differential expression is presented,which ensures the eq...Dynamic model for dehydration process of industrial purified terephthalic acid solvent is investigated to understand and characterize the process.A temperature differential expression is presented,which ensures the equation to convergence and short computation time.The model is used to study the dynamic behavior of an azeotropic distillation column separating acetic acid and water using n-butyl acetate as the entrainer.Responses of the column to feed flow and aqueous reflux flow are simulated.The movement of temperature front is also simulated.The comparison between simulation and industrial values shows that the model and algorithm are effective.On the basis of simulation and analysis,control strategy,online optimization and so on can be implemented effectively in dehydration process of purified terephthalic acid solvent.展开更多
Multi-objective optimization of a purified terephthalic acid (PTA) oxidation unit is carried out in this paper by using a process modei that has been proved to describe industrial process quite well. The modei is a se...Multi-objective optimization of a purified terephthalic acid (PTA) oxidation unit is carried out in this paper by using a process modei that has been proved to describe industrial process quite well. The modei is a semi-empirical structured into two series ideal continuously stirred tank reactor (CSTR) models. The optimal objectives include maximizing the yield or inlet rate and minimizing the concentration of 4-carboxy-benzaldhyde, which is the main undesirable intermediate product in the reaction process. The multi-objective optimization algorithra applied in this study is non-dominated sorting genetic algorithm Ⅱ (NSGA-Ⅱ). The performance of NSGA-Ⅱ is further illustrated by application to the title process.展开更多
A fuzzy neural network (FNN) model is developed to predict the 4-CBA concentration of the oxidation unit in purified terephthalic acid process. Several technologies are used to deal with the process data before modeli...A fuzzy neural network (FNN) model is developed to predict the 4-CBA concentration of the oxidation unit in purified terephthalic acid process. Several technologies are used to deal with the process data before modeling.First,a set of preliminary input variables is selected according to prior knowledge and experience. Secondly,a method based on the maximum correlation coefficient is proposed to detect the dead time between the process variables and response variables. Finally, the fuzzy curve method is used to reduce the unimportant input variables.The simulation results based on industrial data show that the relative error range of the FNN model is narrower than that of the American Oil Company (AMOCO) model. Furthermore, the FNN model can predict the trend of the 4-CBA concentration more accurately.展开更多
The biodegradation and toxicity of the purified terephthalic acid（PTA） processing wastewater was researched at NJYZ pilot with the fusant strain Fhhh in the carrier activated sludge process（ CASP）. Sludge loading ...The biodegradation and toxicity of the purified terephthalic acid（PTA） processing wastewater was researched at NJYZ pilot with the fusant strain Fhhh in the carrier activated sludge process（ CASP）. Sludge loading rate（SLR） for Fhhh to COD of the wastewater was 1.09 d^-1 and to PTA in the wastewater was 0.29 d^-1. The results of bioassay at the pilot and calculation with software Ebis3 showed that the 48h-LC50 （median lethal concentration） to Daphnia magna for the PTA concentration in the wastewater was only 1/10 of that for the chemical PTA. There were .5 kinds of benzoate pollutants and their toxicities existing in the wastewater at least. The toxicity parameter value of the pure chemical PTA cannot be used to predicate the PTA wastewater toxicity. The toxicity of the NJYZ PTA wastewater will be discussed in detail in this paper.展开更多
Decreasing the acetic acid consumption in purified terephthalic acid （PTA） solvent system has become a hot issue with common concern. In accordance with the technical features, the electrical conductivity is in dire...Decreasing the acetic acid consumption in purified terephthalic acid （PTA） solvent system has become a hot issue with common concern. In accordance with the technical features, the electrical conductivity is in direct proportion to the acetic acid content. General regression neural network （GRNN） is used to establish the model of electrical conductivity on the basis of mechanism analysis, and then particle swarm optimization （PSO） algorithm with the improvement of inertia weight and population diversity is proposed to regulate the operating conditions. Thus, the method of decreasing the acid loss is derived and applied to PTA solvent system in a chemical plant. Cases studies show that the precision of modeling and optimization are higher. The results also provide the optimal operating conditions, which decrease the cost and improve the profit.展开更多
Non-dispersive solvent extraction （NDSE） with p-xylene as extractant was employed as a novel separation methodto recover both ρ-toluic （PT） acid and water from purified terephthalic acid （PTA） wastewater. The m...Non-dispersive solvent extraction （NDSE） with p-xylene as extractant was employed as a novel separation methodto recover both ρ-toluic （PT） acid and water from purified terephthalic acid （PTA） wastewater. The mass transport behavior ofPT acid from aqueous solution to ρ-xylene was investigated by experiments and numerical simulation. Experiments showed thatNDSE is feasible and effective. Residual PT acid in the raffinate can be reduced to lower than the permitted limit of wastewaterre-use （100 g/m^3） with extraction time longer than 60 s in industrial conditions. A mathematical model of PT acid mass transportwas developed to optimize the membrane module performance. The model was validated with the experimental results withrelative errors of less than 6%. Numerical analysis for mass transfer through the lumen side, the porous membrane layer, and theshell side showed that PT acid transport in the aqueous solution is the rate determining step. The effects of the membrane andoperating parameters on membrane module performance were investigated by means of computational simulations. The keyparameters suggested for industrial NDSE design are： fiber inner radius r1=200-250 μm, extraction time tc=50-60 s, aqueous/organic volumetric ratio a/o=9.0, and temperature T-318 K.展开更多
基金Supported by the National Natural Science Foundation of China（61072127） the Outstanding Young Innovative Personnel Project of Guangdong Colleges（LYM08098）
文摘Dynamic model for dehydration process of industrial purified terephthalic acid solvent is investigated to understand and characterize the process.A temperature differential expression is presented,which ensures the equation to convergence and short computation time.The model is used to study the dynamic behavior of an azeotropic distillation column separating acetic acid and water using n-butyl acetate as the entrainer.Responses of the column to feed flow and aqueous reflux flow are simulated.The movement of temperature front is also simulated.The comparison between simulation and industrial values shows that the model and algorithm are effective.On the basis of simulation and analysis,control strategy,online optimization and so on can be implemented effectively in dehydration process of purified terephthalic acid solvent.
基金National Key Technologies Research and Development Program in the 10th Five-year Phan(No.2001BA204B01)National Outstanding Youth Science Foundation of China(No.60025308)
文摘Multi-objective optimization of a purified terephthalic acid (PTA) oxidation unit is carried out in this paper by using a process modei that has been proved to describe industrial process quite well. The modei is a semi-empirical structured into two series ideal continuously stirred tank reactor (CSTR) models. The optimal objectives include maximizing the yield or inlet rate and minimizing the concentration of 4-carboxy-benzaldhyde, which is the main undesirable intermediate product in the reaction process. The multi-objective optimization algorithra applied in this study is non-dominated sorting genetic algorithm Ⅱ (NSGA-Ⅱ). The performance of NSGA-Ⅱ is further illustrated by application to the title process.
基金Supported by the National Outstanding Youth Science Foundation of China (No. 60025308).
文摘A fuzzy neural network (FNN) model is developed to predict the 4-CBA concentration of the oxidation unit in purified terephthalic acid process. Several technologies are used to deal with the process data before modeling.First,a set of preliminary input variables is selected according to prior knowledge and experience. Secondly,a method based on the maximum correlation coefficient is proposed to detect the dead time between the process variables and response variables. Finally, the fuzzy curve method is used to reduce the unimportant input variables.The simulation results based on industrial data show that the relative error range of the FNN model is narrower than that of the American Oil Company (AMOCO) model. Furthermore, the FNN model can predict the trend of the 4-CBA concentration more accurately.
基金Ph.D Fund of the National Education Ministry of China(20030284038) and the Hi-Tech Research and Development Program (863) of China(2001AA216191)
文摘The biodegradation and toxicity of the purified terephthalic acid（PTA） processing wastewater was researched at NJYZ pilot with the fusant strain Fhhh in the carrier activated sludge process（ CASP）. Sludge loading rate（SLR） for Fhhh to COD of the wastewater was 1.09 d^-1 and to PTA in the wastewater was 0.29 d^-1. The results of bioassay at the pilot and calculation with software Ebis3 showed that the 48h-LC50 （median lethal concentration） to Daphnia magna for the PTA concentration in the wastewater was only 1/10 of that for the chemical PTA. There were .5 kinds of benzoate pollutants and their toxicities existing in the wastewater at least. The toxicity parameter value of the pure chemical PTA cannot be used to predicate the PTA wastewater toxicity. The toxicity of the NJYZ PTA wastewater will be discussed in detail in this paper.
基金Supported by the National Natural Science Foundation of China （60774079）, the National High Technology Research and Development Program of China （2006AA04Z184）, and Sinopec Science ＆ Technology Development Project of China （205073）.
文摘Decreasing the acetic acid consumption in purified terephthalic acid （PTA） solvent system has become a hot issue with common concern. In accordance with the technical features, the electrical conductivity is in direct proportion to the acetic acid content. General regression neural network （GRNN） is used to establish the model of electrical conductivity on the basis of mechanism analysis, and then particle swarm optimization （PSO） algorithm with the improvement of inertia weight and population diversity is proposed to regulate the operating conditions. Thus, the method of decreasing the acid loss is derived and applied to PTA solvent system in a chemical plant. Cases studies show that the precision of modeling and optimization are higher. The results also provide the optimal operating conditions, which decrease the cost and improve the profit.
基金supported by the National Natural Science Foundation of China(No.20806072)
文摘Non-dispersive solvent extraction （NDSE） with p-xylene as extractant was employed as a novel separation methodto recover both ρ-toluic （PT） acid and water from purified terephthalic acid （PTA） wastewater. The mass transport behavior ofPT acid from aqueous solution to ρ-xylene was investigated by experiments and numerical simulation. Experiments showed thatNDSE is feasible and effective. Residual PT acid in the raffinate can be reduced to lower than the permitted limit of wastewaterre-use （100 g/m^3） with extraction time longer than 60 s in industrial conditions. A mathematical model of PT acid mass transportwas developed to optimize the membrane module performance. The model was validated with the experimental results withrelative errors of less than 6%. Numerical analysis for mass transfer through the lumen side, the porous membrane layer, and theshell side showed that PT acid transport in the aqueous solution is the rate determining step. The effects of the membrane andoperating parameters on membrane module performance were investigated by means of computational simulations. The keyparameters suggested for industrial NDSE design are： fiber inner radius r1=200-250 μm, extraction time tc=50-60 s, aqueous/organic volumetric ratio a/o=9.0, and temperature T-318 K.
