A pulse feed vertical flow constructed wetland (VFCW) proved to be efficient in the treatment of ... more A pulse feed vertical flow constructed wetland (VFCW) proved to be efficient in the treatment of a textile effluent being able to buffer, dilute and treat an Acid Orange (AO7) accidental discharge. The influence of the flooding level (FL) and pulse feed (PF) duration on the removal efficiencies of a VFCW was examined. Average AO7 removal efficiencies of 70% were achieved for an AO7 Inlet concentration of 700 mg l−1 applied during 15 min cycle−1 (every three hours) at a hydraulic load of 13 l m−2 cycle−1 and an FL of 21%. The VFCW was modelled by analogy with a combination of ideal reactors. The simplest combination that best reproduced the experimental results was an association of 2 reactors in series plus 1 reactor accounting the dead volumes. The model parameters helped to understand the hydrological and kinetic processes occurring in VFCW. Through the model simulation it was shown that 3 VFCW in series were enough to efficiently treat an organic mass load of 76 gAO7 m−2 day−1 in...
Automating the generation of suitable kinetic models could dramatically improve its application t... more Automating the generation of suitable kinetic models could dramatically improve its application to novel reactions. Therefore, a software tool was developed to automatically propose rate equations for a catalytic reaction, purely based on experimental data. The tool screens theoretical initial rate equations by comparing the trends predicted by theoretical equations (from a comprehensive library) with those present in the experimental data, thus eliminating the rate equations that cannot reproduce the trends in the data. Afterwards, the kinetic models associated to the feasible rate equations are ranked based on trend similarity, resulting in an ordered list of models ready for regression. For most of the tested literature datasets, the tool proposed the same rate equation as experienced researchers. This is a key first step into the automation of kinetic modelling that, once generalized, will allow to its widespread use in the understanding of catalytic reactions.
The industrial process complexity of biogas production is often a drawback to optimization. Kinet... more The industrial process complexity of biogas production is often a drawback to optimization. Kinetic models allowed the understanding of current phenomenon in reactors making possible the automation and control. To deepen the knowledge of the process, a bibliographic research of the scientific, technological and monitoring state-of-art of the anaerobic digestion process was made, including performance calculations to find parameters best suited for optimization. A mathematical model that describes the general degradation of organic fraction of municipal solid waste (OFMSW) in full scale reactors was then developed. The current study is based on models developed by several authors, where it was included the microbial growth kinetics, each one with their own parameters, found in the bibliography. The kinetic flux was divided into three processes: hydrolysis, acidogenic/acetogenic and methanogenic. The model simulates the decomposition of low biodegradable matter in high biodegradable m...
Although aniline synthesis via nitrobenzene hydrogenation is well documented, research about simu... more Although aniline synthesis via nitrobenzene hydrogenation is well documented, research about simultaneous by-product formation is still scarce. The understanding of undesired side reactions has significant implications for process design, including both the reactor and separation units, and also for tackling important environmental issues. To achieve optimum aniline selectivity, a kinetic mechanism and model, able to predict by-product formation during nitrobenzene hydrogenation at an industrial scale, are fundamental tools. The formation of by-products in the nitrobenzene hydrogenation to aniline was studied in a CSTR during transient operation, using a Ni/SiO2 catalyst. Introducing different 2 quantities of the detected by-products in the feed stream, and observing their time evolution during the transient operation, the interactions between the different species were determined. The proposed new mechanism that is now presented, considers all detected species, and the experimental results were simultaneously adjusted to a relative error of approx. 10%. The new mechanism is able to explain the formation of cyclohexanone, and its subsequent hydrogenation to cyclohexanol, and also provides new insights on the interconversion between cyclohexanone and N-cyclohexylideneaniline.
Demonstrate the use of a continuous reactor for chemical kinetics analysis of a strong exothermic reaction.
Demonstrate the use of COPASI in semicontinuous flow reactors.
A pulse feed vertical flow constructed wetland (VFCW) proved to be efficient in the treatment of ... more A pulse feed vertical flow constructed wetland (VFCW) proved to be efficient in the treatment of a textile effluent being able to buffer, dilute and treat an Acid Orange (AO7) accidental discharge. The influence of the flooding level (FL) and pulse feed (PF) duration on the removal efficiencies of a VFCW was examined. Average AO7 removal efficiencies of 70% were achieved for an AO7 Inlet concentration of 700 mg l−1 applied during 15 min cycle−1 (every three hours) at a hydraulic load of 13 l m−2 cycle−1 and an FL of 21%. The VFCW was modelled by analogy with a combination of ideal reactors. The simplest combination that best reproduced the experimental results was an association of 2 reactors in series plus 1 reactor accounting the dead volumes. The model parameters helped to understand the hydrological and kinetic processes occurring in VFCW. Through the model simulation it was shown that 3 VFCW in series were enough to efficiently treat an organic mass load of 76 gAO7 m−2 day−1 in...
Automating the generation of suitable kinetic models could dramatically improve its application t... more Automating the generation of suitable kinetic models could dramatically improve its application to novel reactions. Therefore, a software tool was developed to automatically propose rate equations for a catalytic reaction, purely based on experimental data. The tool screens theoretical initial rate equations by comparing the trends predicted by theoretical equations (from a comprehensive library) with those present in the experimental data, thus eliminating the rate equations that cannot reproduce the trends in the data. Afterwards, the kinetic models associated to the feasible rate equations are ranked based on trend similarity, resulting in an ordered list of models ready for regression. For most of the tested literature datasets, the tool proposed the same rate equation as experienced researchers. This is a key first step into the automation of kinetic modelling that, once generalized, will allow to its widespread use in the understanding of catalytic reactions.
The industrial process complexity of biogas production is often a drawback to optimization. Kinet... more The industrial process complexity of biogas production is often a drawback to optimization. Kinetic models allowed the understanding of current phenomenon in reactors making possible the automation and control. To deepen the knowledge of the process, a bibliographic research of the scientific, technological and monitoring state-of-art of the anaerobic digestion process was made, including performance calculations to find parameters best suited for optimization. A mathematical model that describes the general degradation of organic fraction of municipal solid waste (OFMSW) in full scale reactors was then developed. The current study is based on models developed by several authors, where it was included the microbial growth kinetics, each one with their own parameters, found in the bibliography. The kinetic flux was divided into three processes: hydrolysis, acidogenic/acetogenic and methanogenic. The model simulates the decomposition of low biodegradable matter in high biodegradable m...
Although aniline synthesis via nitrobenzene hydrogenation is well documented, research about simu... more Although aniline synthesis via nitrobenzene hydrogenation is well documented, research about simultaneous by-product formation is still scarce. The understanding of undesired side reactions has significant implications for process design, including both the reactor and separation units, and also for tackling important environmental issues. To achieve optimum aniline selectivity, a kinetic mechanism and model, able to predict by-product formation during nitrobenzene hydrogenation at an industrial scale, are fundamental tools. The formation of by-products in the nitrobenzene hydrogenation to aniline was studied in a CSTR during transient operation, using a Ni/SiO2 catalyst. Introducing different 2 quantities of the detected by-products in the feed stream, and observing their time evolution during the transient operation, the interactions between the different species were determined. The proposed new mechanism that is now presented, considers all detected species, and the experimental results were simultaneously adjusted to a relative error of approx. 10%. The new mechanism is able to explain the formation of cyclohexanone, and its subsequent hydrogenation to cyclohexanol, and also provides new insights on the interconversion between cyclohexanone and N-cyclohexylideneaniline.
Demonstrate the use of a continuous reactor for chemical kinetics analysis of a strong exothermic reaction.
Demonstrate the use of COPASI in semicontinuous flow reactors.
Uploads
Demonstrate the use of a continuous reactor for chemical kinetics analysis of a strong exothermic reaction.
Demonstrate the use of COPASI in semicontinuous flow reactors.
Demonstrate the use of a continuous reactor for chemical kinetics analysis of a strong exothermic reaction.
Demonstrate the use of COPASI in semicontinuous flow reactors.