The Experts below are selected from a list of 5157 Experts worldwide ranked by ideXlab platform
Guy A Dumont - One of the best experts on this subject based on the ideXlab platform.
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predictive optimal control for thermo Mechanical Pulping processes with multi stage low consistency refining
Journal of Process Control, 2013Co-Authors: Eranda Harinath, Lorenz T Biegler, Guy A DumontAbstract:Abstract In this paper, we present a nonlinear model based dynamic optimization approach for optimal control for thermo-Mechanical Pulping (TMP) processes. The method is based on nonlinear model predictive control (NMPC) technique with an economic objective function. In our previous work [1] , an economically oriented NMPC (econNMPC) was presented for a two-stage TMP process with high consistency (HC) refiners. The two-stage TMP process was simulated up to the secondary refiner. In this study, we extend the previous study to multiple stages that include low consistency (LC) refining. Here we can exploit the complexity of interactions of multiple stage TMP for both performance and optimal operations. The first process is a conventional refining process with two stages of HC refining with a primary and a secondary refiner, followed by a latency chest and a third-stage LC refiner. The second TMP process has only a HC primary refiner, and the secondary stage HC refiner is replaced by multiple stages of LC refiners after the latency chest. Both TMP schemes are dynamically optimized against disturbances to produce the same target final pulp qualities while minimizing specific energy consumption of the processes. The simulation results show the potential economic benefits of the proposed method, through a reduction in total specific energy, about 24%, for the second TMP process.
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control and optimization strategies for thermo Mechanical Pulping processes nonlinear model predictive control
Journal of Process Control, 2011Co-Authors: Eranda Harinath, Lorenz T Biegler, Guy A DumontAbstract:Abstract In this paper, we present nonlinear model predictive control (NMPC) techniques to control and optimize the thermo-Mechanical Pulping (TMP) process. The TMP process considered in this work has two-stages of refining with a primary and a secondary refiners. TMP processes are, inherently, multi-input multi-output (MIMO) processes with complex dynamics and severe interactions among process variables. We formulate a dynamic optimization problem to simultaneously regulate and optimize the TMP process and compare with regulatory control in the presence of disturbances. Potential economical benefits of the proposed method are demonstrated, through a reduction in total specific energy. The computational burden of the resulting nonlinear programming problem (NLP) is handled with the IPOPT (Interior Point OPTimizer) solver. This is further improved with the advanced step NMPC (asNMPC) controller concept, a sensitivity-based approximation to the solution of the resulting NLP problem in NMPC.
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advanced step nonlinear model predictive control for two stage thermo Mechanical Pulping processes
IFAC Proceedings Volumes, 2011Co-Authors: Eranda Harinath, Lorenz T Biegler, Guy A DumontAbstract:Abstract In this work, we use a general nonlinear model predictive control (NMPC) technique for the two-stage (primary and secondary refining) thermo-Mechanical Pulping (TMP) refining process. The NMPC strategy is based on empirical and first-principle models which describe dynamic behavior and interactions among process variables. The computational burden is one of main drawbacks of NMPC controllers when applied to real systems. In this work, we handle the computational burden of the resulting nonlinear programming (NLP) problem using the IPOPT (Interior Point OPTimizer) solver. This is further improved with the advanced step NMPC (asNMPC) controller concept, a sensitivity based approximation to the solution of the resulting NLP. The simulation study compares the performances of the ideal-NMPC and the asNMPC strategies. The asNMPC controller reduces the CPU time and performs well in the presence of disturbances.
Eranda Harinath - One of the best experts on this subject based on the ideXlab platform.
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predictive optimal control for thermo Mechanical Pulping processes with multi stage low consistency refining
Journal of Process Control, 2013Co-Authors: Eranda Harinath, Lorenz T Biegler, Guy A DumontAbstract:Abstract In this paper, we present a nonlinear model based dynamic optimization approach for optimal control for thermo-Mechanical Pulping (TMP) processes. The method is based on nonlinear model predictive control (NMPC) technique with an economic objective function. In our previous work [1] , an economically oriented NMPC (econNMPC) was presented for a two-stage TMP process with high consistency (HC) refiners. The two-stage TMP process was simulated up to the secondary refiner. In this study, we extend the previous study to multiple stages that include low consistency (LC) refining. Here we can exploit the complexity of interactions of multiple stage TMP for both performance and optimal operations. The first process is a conventional refining process with two stages of HC refining with a primary and a secondary refiner, followed by a latency chest and a third-stage LC refiner. The second TMP process has only a HC primary refiner, and the secondary stage HC refiner is replaced by multiple stages of LC refiners after the latency chest. Both TMP schemes are dynamically optimized against disturbances to produce the same target final pulp qualities while minimizing specific energy consumption of the processes. The simulation results show the potential economic benefits of the proposed method, through a reduction in total specific energy, about 24%, for the second TMP process.
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control and optimization strategies for thermo Mechanical Pulping processes nonlinear model predictive control
Journal of Process Control, 2011Co-Authors: Eranda Harinath, Lorenz T Biegler, Guy A DumontAbstract:Abstract In this paper, we present nonlinear model predictive control (NMPC) techniques to control and optimize the thermo-Mechanical Pulping (TMP) process. The TMP process considered in this work has two-stages of refining with a primary and a secondary refiners. TMP processes are, inherently, multi-input multi-output (MIMO) processes with complex dynamics and severe interactions among process variables. We formulate a dynamic optimization problem to simultaneously regulate and optimize the TMP process and compare with regulatory control in the presence of disturbances. Potential economical benefits of the proposed method are demonstrated, through a reduction in total specific energy. The computational burden of the resulting nonlinear programming problem (NLP) is handled with the IPOPT (Interior Point OPTimizer) solver. This is further improved with the advanced step NMPC (asNMPC) controller concept, a sensitivity-based approximation to the solution of the resulting NLP problem in NMPC.
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advanced step nonlinear model predictive control for two stage thermo Mechanical Pulping processes
IFAC Proceedings Volumes, 2011Co-Authors: Eranda Harinath, Lorenz T Biegler, Guy A DumontAbstract:Abstract In this work, we use a general nonlinear model predictive control (NMPC) technique for the two-stage (primary and secondary refining) thermo-Mechanical Pulping (TMP) refining process. The NMPC strategy is based on empirical and first-principle models which describe dynamic behavior and interactions among process variables. The computational burden is one of main drawbacks of NMPC controllers when applied to real systems. In this work, we handle the computational burden of the resulting nonlinear programming (NLP) problem using the IPOPT (Interior Point OPTimizer) solver. This is further improved with the advanced step NMPC (asNMPC) controller concept, a sensitivity based approximation to the solution of the resulting NLP. The simulation study compares the performances of the ideal-NMPC and the asNMPC strategies. The asNMPC controller reduces the CPU time and performs well in the presence of disturbances.
Per Engstrand - One of the best experts on this subject based on the ideXlab platform.
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low consistency refining combined with screen fractionation reduction of Mechanical Pulping process complexity
Bioresources, 2019Co-Authors: Christer Sandberg, Jan-erik Berg, Per EngstrandAbstract:Process intensification is a process development methodology aimed at a considerable reduction in the energy consumption and process complexity. The approach has been applied to Mechanical Pulping process design. A process denoted as HC-LC-S consisting of single stage high consistency (HC) refining, followed by low consistency (LC) refining and screening was evaluated in mill trials at the Holmen Paper Braviken Mill in Sweden. After LC refining, the pulp was screened, and the reject fraction was fed back to LC refining. Two HC primary refiner types were evaluated, namely single disc (SD) and double disc (DD). Double disc chip refining was more suitable than SD refining for the HC-LC-S process because of the higher light scattering and lower shives content of the final pulp. The tensile index and shives content of the pulp produced with the DD-LC-S process was similar to that of the reference process, consisting of single stage DD refining and HC reject refining, but the fibre length and light scattering were somewhat lower. The specific refining energy was approximately 200 kWh/adt lower for the DD-LC-S process compared with the reference. Additionally, the auxiliary specific energy was 100 kWh/adt lower for the HC-LC-S processes, since a number of equipment units were omitted.
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LC refining combined with screen fractionation – Reduction of system complexity for Mechanical Pulping
2018Co-Authors: Christer Sandberg, Jan-erik Berg, Per EngstrandAbstract:Process intensification - a process development method used in the chemical process industry has been appliedto Mechanical Pulping process design. Process intensification is characterized by signif ...
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The Independent State of Fibres in Relation to the Mechanical Pulping World
2018Co-Authors: Olof Ferritsius, Birgitta A. Engberg, Rita Ferritsius, Mats Rundlöf, Per EngstrandAbstract:Paper and wood are highly inhomogeneous materials. When describing the Mechanical pulp itself, we allcommonly ignore that it is an inhomogeneous material. We have realized that just a very small fr ...
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process intensification in Mechanical Pulping
Nordic Pulp & Paper Research Journal, 2017Co-Authors: Christer Sandberg, Jan-erik Berg, Per EngstrandAbstract:Process intensification is a term used in the chemical process industry for major improvements in the process design leading to radical changes in process complexity, equipment size and efficiency. ...
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Low consistency refining of Mechanical pulp - system design
Tappi Journal, 2017Co-Authors: Christer Sandberg, Jan-erik Berg, Per EngstrandAbstract:Many Mechanical Pulping mills use low consistency (LC) refining for energy efficient fiber development. In this study, energy efficiency and pulp quality were evaluated for six processes, of which ...
Yonghao Ni - One of the best experts on this subject based on the ideXlab platform.
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treatment of apmp Pulping effluent based on aerobic fermentation with aspergillus niger and post coagulation flocculation
Bioresource Technology, 2011Co-Authors: Zhibin He, Huiren Hu, Yonghao NiAbstract:A novel two-stage biological/flocculation process was developed for treating the Pulping effluent from the alkaline peroxide Mechanical Pulping (APMP) process. In the first biological stage, the aerobic fermentation by using Aspergillus niger can decrease the chemical oxygen demand (COD) by about 60% while producing about 7 g/l of solid biomass. In the second stage (post-coagulation/flocculation), the residual COD, turbidity and color, can be further decreased by using alum and polyacrylamide (PAM). The overall removal efficiencies of COD, color and turbidity from the APMP Pulping effluent by the above two-stage biological-coagulation/flocculation process were 93%, 92% and 99%, respectively, under the conditions studied.
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Treatment of APMP Pulping effluent based on aerobic fermentation with Aspergillus niger and post-coagulation/flocculation.
Bioresource Technology, 2011Co-Authors: Zhibin He, Huiren Hu, Yonghao NiAbstract:A novel two-stage biological/flocculation process was developed for treating the Pulping effluent from the alkaline peroxide Mechanical Pulping (APMP) process. In the first biological stage, the aerobic fermentation by using Aspergillus niger can decrease the chemical oxygen demand (COD) by about 60% while producing about 7 g/l of solid biomass. In the second stage (post-coagulation/flocculation), the residual COD, turbidity and color, can be further decreased by using alum and polyacrylamide (PAM). The overall removal efficiencies of COD, color and turbidity from the APMP Pulping effluent by the above two-stage biological-coagulation/flocculation process were 93%, 92% and 99%, respectively, under the conditions studied.
John N Saddler - One of the best experts on this subject based on the ideXlab platform.
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the influence of lignin on steam pretreatment and Mechanical Pulping of poplar to achieve high sugar recovery and ease of enzymatic hydrolysis
Bioresource Technology, 2016Co-Authors: Richard P Chandra, Qiulu Chu, Na Zhong, Mandy Lin, Jinsuk Lee, John N SaddlerAbstract:With the goal of enhancing overall carbohydrate recovery and reducing enzyme loading refiner Mechanical Pulping and steam pretreatment (210°C, 5 min) were used to pretreat poplar wood chips. Neutral sulphonation post-treatment indicated that, although the lignin present in the steam pretreated substrate was less reactive, the cellulose-rich, water insoluble component was more accessible to cellulases and Simons stain. This was likely due to lignin relocation as the relative surface lignin measured by X-ray photoelectron spectroscopy increased from 0.4 to 0.8. The integration of sulphite directly into steam pretreatment resulted in the solubilisation of 60% of the lignin while more than 80% of the carbohydrate present in the original substrate was recovered in the water insoluble fraction after Na2CO3 addition. More than 80% of the sugars present in the original cellulose and xylan could be recovered after 48 h using an enzyme loading of 20 mg protein/g cellulose at a 10% substrate concentration.
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fate and influence of western red cedar extractives in Mechanical Pulping
Wood Science and Technology, 2000Co-Authors: C I Johansson, Rodger P Beatson, John N SaddlerAbstract:The methanol extractives from western red cedar Mechanical pulps were found to be radically different in composition to the extractives obtained from the heartwood. The major heartwood extractive components, the tropolones and lignans, were not present in the extractives from the pulps. However, the proportion of a brown polymer doubled. The low and high molecular weight methanol extractives components from the pulps were separated using methyl tert-butyl ether. The low molecular fraction contained mostly guaiacyl-based compounds with dihydroquercetin, thujic acid, 3-hydroxy-1-(4′-hydroxy-3′-methoxyphenyl)-2-oxopropane and 4-ethyl-2-methoxy-6-hydroxyphenol being positively identified. The brown polymeric portion had molecular weights ranging from 1,000 to 10,000. Infrared analysis indicated that the polymers were formed from lignans. Examination of the changes in diffuse reflectance UV-visible and infra red spectra of the pulps on extraction with methanol, suggested that the colour resides in insoluble polymers formed from plicatic acid/plicatin during refining.