The focus of this paper is to investigate different control structures(single-loop PI control) for a dividing wall(Petlyuk) column for separating ethanol, n-propanol and n-butanol. Four control structures are studied....The focus of this paper is to investigate different control structures(single-loop PI control) for a dividing wall(Petlyuk) column for separating ethanol, n-propanol and n-butanol. Four control structures are studied. All the results are simulations based on Aspen Plus. Control structure 1(CS1) is stabilizing control structure with only temperature controllers. CS2, CS3 and CS4, containing also composition controllers, are introduced to reduce the steady state composition deviations. CS2 adds a distillate composition controller(CCDB) on top of CS1. CS3 is much more complicated with three temperature-composition cascade controllers and in addition a selector to the reboiler duty to control the maximum controller output of light impurity composition control in side stream and bottom impurity control in the prefractionator. CS4 adds another high selector to control the light impurity in the sidestream. Surprisingly, when considering the dynamic and even steady state performance of the proposed control structures, CS1 proves to be the best control structure to handle feed disturbances inserted into the three-product Petlyuk column.展开更多
A recently developed control strategy for the anaerobic digestion process requires secure knowledge about the state of the process.The near infrared reflection spectroscopy(NIRS),provides the possibility to determine ...A recently developed control strategy for the anaerobic digestion process requires secure knowledge about the state of the process.The near infrared reflection spectroscopy(NIRS),provides the possibility to determine process parameters of the anaerobic digestion process online and directly at the digester.To investigate if the NIRS measurements can successfully be used for the characterization of the state of the process within the control strategy the control was operated on two experimental digesters.The NIR spectra were recorded during the experiments.The values of the process parameters(mainly concentrations of organic acids)obtained by NIRS differ from the values of the chemical analyses during the experiment.Nevertheless the state of the process is categorized equally on the basis of both measurement methods.It can consequently be stated that NIRS is expected to meet the requirements of the control strategy.展开更多
Automatic process control (APC) based on design of experiment (DOE) is a cost-efficient approach for variation reduction. The process changes both in mean and variance owing to online parameter adjustment make it hard...Automatic process control (APC) based on design of experiment (DOE) is a cost-efficient approach for variation reduction. The process changes both in mean and variance owing to online parameter adjustment make it hard to apply traditional SPC charts in such DOE-based APC applied process. An adaptive SPC scheme is developed, which can better track the process transitions and achieve the possible SPC run cost reduction when the process is stable. The control law of SPC parameters is designed by fully utilizing the estimation properties of the process model instead of traditionally using the data collected from the production line. An example is provided to illustrate the proposed adaptive SPC design approach.展开更多
基金Supported by the National Basic Research Program of China(973 Program:2012CB720500)the National Supporting Research Program of China(Grant2013BAA03B01)+2 种基金the National Natural Science Foundation of China(21176178)the China Scholarship Council(201506250011)the China Postdoctoral Science Foundation(2017M620587)
文摘The focus of this paper is to investigate different control structures(single-loop PI control) for a dividing wall(Petlyuk) column for separating ethanol, n-propanol and n-butanol. Four control structures are studied. All the results are simulations based on Aspen Plus. Control structure 1(CS1) is stabilizing control structure with only temperature controllers. CS2, CS3 and CS4, containing also composition controllers, are introduced to reduce the steady state composition deviations. CS2 adds a distillate composition controller(CCDB) on top of CS1. CS3 is much more complicated with three temperature-composition cascade controllers and in addition a selector to the reboiler duty to control the maximum controller output of light impurity composition control in side stream and bottom impurity control in the prefractionator. CS4 adds another high selector to control the light impurity in the sidestream. Surprisingly, when considering the dynamic and even steady state performance of the proposed control structures, CS1 proves to be the best control structure to handle feed disturbances inserted into the three-product Petlyuk column.
基金The authors thank the Ministry for Rural Areas and Consumer Protection of the federal state of Baden-Württemberg(Germany)and the Baden-Württemberg Foundation gGmbH for the financial support of the project within the“research platform on bioenergy”.
文摘A recently developed control strategy for the anaerobic digestion process requires secure knowledge about the state of the process.The near infrared reflection spectroscopy(NIRS),provides the possibility to determine process parameters of the anaerobic digestion process online and directly at the digester.To investigate if the NIRS measurements can successfully be used for the characterization of the state of the process within the control strategy the control was operated on two experimental digesters.The NIR spectra were recorded during the experiments.The values of the process parameters(mainly concentrations of organic acids)obtained by NIRS differ from the values of the chemical analyses during the experiment.Nevertheless the state of the process is categorized equally on the basis of both measurement methods.It can consequently be stated that NIRS is expected to meet the requirements of the control strategy.
基金the National Natural Science Foundation of China (50405016 70671065).
文摘Automatic process control (APC) based on design of experiment (DOE) is a cost-efficient approach for variation reduction. The process changes both in mean and variance owing to online parameter adjustment make it hard to apply traditional SPC charts in such DOE-based APC applied process. An adaptive SPC scheme is developed, which can better track the process transitions and achieve the possible SPC run cost reduction when the process is stable. The control law of SPC parameters is designed by fully utilizing the estimation properties of the process model instead of traditionally using the data collected from the production line. An example is provided to illustrate the proposed adaptive SPC design approach.
